Article

Two-level cervical disc arthroplasty versus anterior cervical discectomy and fusion: 10-year outcomes of a prospective, randomized investigational device exemption clinical trial

June 2019
Journal of neurosurgery. Spine 31(4):1-11

DOI:10.3171/2019.4.SPINE19157

Authors:

Matthew F Gornet

The Orthopedic Center of St. Louis

John Kenneth Burkus

Hughston Clinic

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Objective: The authors assessed the 10-year clinical safety and effectiveness of cervical disc arthroplasty (CDA) to treat degenerative cervical spine disease at 2 adjacent levels compared to anterior cervical discectomy and fusion (ACDF). Methods: A prospective, randomized, controlled, multicenter FDA-approved clinical trial was conducted comparing the low-profile titanium ceramic composite-based Prestige LP Cervical Disc (n = 209) at two levels with ACDF (n = 188). Ten-year follow-up data from a postapproval study were available on 148 CDA and 118 ACDF patients and are reported here. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at regular postoperative follow-up intervals for up to 10 years. The primary endpoint was overall success, a composite variable that included key safety and efficacy considerations. Ten-year follow-up rates were 86.0% for CDA and 84.9% for ACDF. Results: From 2 to 10 years, CDA demonstrated statistical superiority over ACDF for overall success, with rates at 10 years of 80.4% versus 62.2%, respectively (posterior probability of superiority [PPS] = 99.9%). Neck Disability Index (NDI) success was also superior, with rates at 10 years of 88.4% versus 76.5% (PPS = 99.5%), as was neurological success (92.6% vs 86.1%; PPS = 95.6%). Improvements from preoperative results in NDI and neck pain scores were consistently statistically superior for CDA compared to ACDF. All other study effectiveness measures were at least noninferior for CDA compared to ACDF through the 10-year follow-up period, including disc height. Mean angular ranges of motion at treated levels were maintained in the CDA group for up to 10 years. The rates of grade IV heterotopic ossification (HO) at the superior and inferior levels were 8.2% and 10.3%, respectively. The rate of severe HO (grade III or IV) did not increase significantly from 7 years (42.4%) to 10 years (39.0%). The CDA group had fewer serious (grade 3-4) implant-related or implant/surgical procedure-related adverse events (3.8% vs 8.1%; posterior mean 95% Bayesian credible interval [BCI] of the log hazard ratio [LHR] -0.92 [-1.88, -0.01]). The CDA group also had statistically fewer secondary surgical procedures at the index levels (4.7%) than the ACDF group (17.6%) (LHR [95% BCI] -1.39 [-2.15, -0.61]) as well as at adjacent levels (9.0% vs 17.9%). Conclusions: The Prestige LP Cervical Disc, implanted at two adjacent levels, maintains improved clinical outcomes and segmental motion 10 years after surgery and is a safe and effective alternative to fusion.Clinical trial registration no.: NCT00637156 (clinicaltrials.gov).

Efficacy of Anterior Cervical Discectomy and Fusion Versus Cervical Disc Arthroplasty in the Treatment of Cervical Degenerative Disc Disease, Radiculopathy, and Myelopathy: A Systematic Review

Article

Full-text available

Nov 2024

Cervical degenerative disc disease (DDD) is a condition in which the discs in the neck deteriorate, causing symptoms including neck and arm pain, muscle weakness, and incoordination. In severe cases, it can lead to nerve and spinal cord compression, resulting in radiculopathy and myelopathy. This review aimed to assess the effectiveness of two surgical treatments, anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA), for addressing cervical DDD, radiculopathy, and myelopathy. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a literature search was conducted in the PubMed and BioMed Central databases from January to March 2024. Thirty-one studies were included, comparing the outcomes of ACDF and CDA in patients with cervical DDD, radiculopathy, and myelopathy. Data were analyzed to evaluate outcomes such as the Neck Disability Index (NDI), pain levels, neurological status, incidence of secondary surgeries, range of motion (ROM) maintenance, and occurrence of adjacent segment disease. CDA demonstrated comparable or superior clinical success to ACDF. Both the techniques showed similar improvements in NDI, pain levels, and neurological status during medium- and long-term follow-ups. CDA had lower rates of secondary surgeries and adverse events related to surgery or implants compared to ACDF. It also demonstrated a lower incidence of adjacent segment disease and better ROM preservation. The evidence supports CDA as a safe and effective alternative to ACDF for patients with cervical DDD, particularly those who may benefit from motion preservation. However, further long-term, multicenter randomized controlled trials are needed to provide more definitive guidance for clinical practice.

Cervical Disc Arthroplasty (CDA) versus Anterior Cervical Discectomy and Fusion (ACDF) for Two-Level Cervical Disc Degenerative Disease: An Updated Systematic Review and Meta-Analysis

Article

Full-text available

May 2024

Background: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are both considered to be efficacious surgical procedures for treating cervical spondylosis in patients with or without compression myelopathy. This updated systematic review and meta-analysis aimed to compare the outcomes of these procedures for the treatment of cervical degenerative disc disease (DDD) at two contiguous levels. Methods: The PubMed, EMBASE, and Cochrane CENTRAL databases were searched up to 1 May 2023. Studies comparing the outcomes between CDA and ACDF in patients with two-level cervical DDD were eligible for inclusion. Primary outcomes were surgical success rates and secondary surgery rates. Secondary outcomes were scores on the Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for neck and arm pain, as well as the Japanese Orthopaedic Association (JOA) score for the severity of cervical compression myelopathy and complication rates. Results: In total, eight studies (two RCTs, four retrospective studies, and two prospective studies) with a total of 1155 patients (CDA: 598; ACDF: 557) were included. Pooled results revealed that CDA was associated with a significantly higher overall success rate (OR, 2.710, 95% CI: 1.949–3.770) and lower secondary surgery rate (OR, 0.254, 95% CI: 0.169–0.382) compared to ACDF. In addition, complication rates were significantly lower in the CDA group than in the ACDF group (OR, 0.548, 95% CI: 0.326 to 0.919). CDA was also associated with significantly greater improvements in neck pain VAS than ACDF. No significant differences were found in improvements in the arm VAS, NDI, and JOA scores between the two procedures. Conclusions: CDA may provide better postoperative outcomes for surgical success, secondary surgery, pain reduction, and postoperative complications than ACDF for treating patients with two-level cervical DDD.

Up to 10-year surveillance comparison of survivability in single-level cervical disc replacement versus anterior cervical discectomy and fusion in New York

Article

Apr 2023
J NEUROSURG-SPINE

Objective: Cervical disc replacement (CDR) is an alternative treatment to anterior cervical discectomy and fusion (ACDF), which is the current gold standard, for degenerative cervical diseases such as cervical spondylotic myelopathy and cervical radiculopathy. CDR has several theoretical benefits over ACDF, including preservation of motion, earlier return to unrestricted activity, and potentially a lower risk of adjacent-segment disease. Recent literature has reported positive clinical results for CDR, but few studies have investigated the long-term risk of revision surgery of CDR versus ACDF. The purpose of this study was to identify and analyze the epidemiological, clinical, and operative risk factors that affect revision rates following single-level CDR and ACDF procedures. Methods: A retrospective cohort was extracted from the Statewide Planning and Research Cooperative System using ICD-9 and CPT codes. Inclusion criteria were adult patients undergoing primary, subaxial (C3-7), single-level ACDF or CDR for cervical radiculopathy and/or cervical spondylotic myelopathy between 2005 and 2013. Survivability was defined as the time between the index procedure and the presence of a subsequent discharge record for cervical spinal fusion or disc replacement. Statistical analyses were performed using chi-square tests, t-tests, Cox proportional hazards models, and a Kaplan-Meier plot. Results: A total of 7450 patients were included in this study (6615 ACDF and 835 CDR). When adjusted for patient demographics, the hazard ratios showed no significant differences in the incidence of revision risk between the two cohorts. The CDR cohort had a higher incidence of postoperative dysphagia (p < 0.05). Patients undergoing ACDF had a longer average hospital stay (2.8 vs 1.9 days, p < 0.001). There was no significant difference in time to revision surgery (p = 0.486). Conclusions: CDR and ACDF have both been shown to be effective treatments for cervical spine disease. CDR patients had a shorter average inpatient hospital stay compared with ACDF patients but tended to experience dysphagia more frequently. There was a tendency toward increased survivability of CDR; however, this was not found to be statistically significant at any time point. The large size and heterogeneity of each cohort and the availability of > 10 years of surveillance data differentiate this study from other published literature. This investigation has limitations inherent to large data analysis studies, including the implementation and inaccuracy of diagnosis and procedural coding; however, this reflects real-world use of coding by practitioners.

Ceramics in total disc replacements: A scoping review

Article

Full-text available

Oct 2022
CLIN BIOMECH

Background Ceramics are used in Total Disc Replacements (1) in articulating surfaces for their wear resistance and biocompatibility and (2) on endplates to promote osseointegration. They furthermore exhibit MRI and CT compatibility. These properties address main challenges associated with non-ceramic Total Disc Replacements i.e. wear, migration and postoperative imaging. While brittleness of ceramics caused fear of fracture in the past, improvements of ceramic materials were made and considerable clinical experience with ceramic Total Disc Replacements was gained. This review aims to assess the evidence on the use of ceramics in Total Disc Replacements and compare safety and effectiveness of ceramic Total Disc Replacements to spinal fusion and Total Disc Replacements in general. Methods We conducted a scoping review on the use of ceramics in Total Disc Replacements using Scopus, Web of Science and PubMed. The review includes 36 clinical, ex vivo and nonhuman in vivo, tribological and mechanical studies and case reports. Findings Ceramics are used in cervical Total Disc Replacements, with safety and efficacy comparable to non-ceramic Total Disc Replacements confirmed in clinical studies, with up to 10 and 3.3 years follow-up, for articulation and osseointegration applications, respectively. Clinical evidence shows that ceramic Total Disc Replacements (alike non-ceramic ones) restore segmental motion and result in non-inferior and possibly superior outcomes to spinal fusion. In vivo studies show osseointegration comparable to non-ceramic devices. Tribological studies suggest appropriate wear properties. Interpretation We found no indications of systematic problems with ceramic Total Disc Replacements. Ceramics are suitable materials for Total Disc Replacements.

Long-Term Survivorship of Cervical Spine Procedures; A Survivorship Meta-Analysis and Meta-Regression

Article

Full-text available

Sep 2022

Study Design Systematic Review Objectives To conduct a meta-analysis on the survivorship of commonly performed cervical spine procedures to develop survival function curves for (i) second surgery at any cervical level, and (ii) adjacent level surgery. Methods A systematic review of was conducted following PRISMA guidelines. Articles with cohorts of greater than 20 patients followed for a minimum of 36 months and with available survival data were included. Procedures included were anterior cervical discectomy and fusion (ACDF), cervical disc arthroplasty (ADR), laminoplasty (LAMP), and posterior laminectomy and fusion (PDIF). Reconstructed individual patient data were pooled across studies using parametric Bayesian survival meta-regression. Results Of 1829 initial titles, 16 citations were included for analysis. 73 811 patients were included in the second surgery analysis and 2858 patients in the adjacent level surgery analysis. We fit a Log normal accelerated failure time model to the second surgery data and a Gompertz proportional hazards model to the adjacent level surgery data. Relative to ACDF, the risk of second surgery was higher with ADR and PDIF with acceleration factors 1.73 (95% CrI: 1.04, 2.80) and 1.35 (95% CrI: 1.25, 1.46) respectively. Relative to ACDF, the risk of second surgery was lower with LAMP with deceleration factor .06 (95% CrI: .05, .07). ADR decreased the risk of adjacent level surgery with hazard ratio .43 (95% CrI: .33, .55). Conclusions In cases of clinical equipoise between fusion procedures, our analysis suggests superior survivorship with anterior procedures. For all procedures, laminoplasty demonstrated superior survivorship.

Combining All Available Clinical Outcomes on Cervical Disc Arthroplasty: A Systematic Review and Meta-Analysis

Article

May 2022

Background: Reviews of total disc arthroplasty (TDA) performance have focused on prospective randomized controlled trials (RCTs), excluding potentially important clinical information reported by others. The goal of the present study was to perform a comprehensive review, including both RCTs and non-randomized cohorts with more than five years of clinical outcome. We further explored the differences in outcome between prospective RCT and non-randomized, including retrospective studies. Methods: A systematic literature review was performed following PRISMA guidelines. Inclusion criteria were: clinical follow-up ≥ 5 years with quantitative clinical and radiographic outcome. All studies that met these criteria, including retrospective and non-randomized studies, were included, for a total of 62 studies. As anterior cervical discectomies and fusion (ACDF) was included as a control group in the majority of the studies, comparisons between TDA and ACDF were conducted. Results: Overall, there was a statistically significant difference between the rates of secondary surgeries reported for prospective RCTs and all other studies, with reoperation rates of 5.4% for prospective RCT studies v. 7.5% in all others (P<0.01). Including all studies, the reoperation rate for TDA patients was 5.6% and for fusion patients (included as control groups), 7.8%, (P=0.06). Overall, the reported incidence of adjacent segment degeneration was 26.2% in TDA patients and 43.9% in fusion patients (P<0.001). Conclusions: These findings demonstrated the need for including all available data to assess the current outcomes of cervical disc arthroplasty and account for potential biases.

Combined effect of artificial cervical disc replacement and facet tropism on the index-level facet joints: a finite element study

Article

Full-text available

Oct 2024
BMC MUSCULOSKEL DIS

Background Artificial Cervical Disc Replacement (ACDR) is an effective treatment for cervical degenerative disc diseases. However, clinical information regarding the facet joint alterations after ACDR was limited. Facet tropism is common in the sub-axial cervical spine. Our previous research indicated that facet tropism could lead to increased pressure on the cervical facet joints. This study aimed to assess the impact of facet tropism on the facet contact force and facet capsule stress after ACDR. Methods A C2–T1 cervical finite element model was constructed from computed tomography (CT) scans of a 28-year-old male volunteer. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level by altering the facet orientation at the C5-C6 level. The C5/C6 ACDR was simulated in the intact, moderate asymmetrical and severe asymmetrical models. A 75-N follower load with 1.0-Nm moments was applied to the top of C2 vertebra in the models to simulate flexion, extension, lateral bending, and axial rotation with the T1 vertebra fixed. The range of motions (ROMs) under all moments, facet contact forces (FCFs) and facet capsule strains were tested. Results In the asymmetrical model, the right FCFs considerably increased under flexion, extension, right bending, left rotation, especially under right bending the right sided FCF of the severe asymmetrical model was about 5.44 times of the neutral position, and 3.14 times of the symmetrical model. and concentrated on the cephalad part of the facets. The facet capsule stresses on both sides remarkably increased under extension, lateral bending and right rotation. In the moderate and severe asymmetrical models, the capsule strain was greater on both sides of each position than in the symmetric model. Conclusions The face tropism increased facet contact force and facet capsule strain after ACDR, especially under extension, lateral bending, and rotation, and also could result in abnormal stress distribution on the facet joint surface and facet joint capsule. The results suggest that face tropism might be a risk factor for post-operative facet joint degeneration progression after ACDR. Facet tropism may be noteworthy when ACDR is considered as a surgical option.

Comparing posterior cervical foraminotomy with anterior cervical discectomy and fusion in radiculopathic patients: an analysis from the Quality Outcomes Database

Article

Apr 2024
J NEUROSURG-SPINE

OBJECTIVE The objective of this study was to compare clinical and patient-reported outcomes (PROs) between posterior foraminotomy and anterior cervical discectomy and fusion (ACDF) in patients presenting with cervical radiculopathy. METHODS The Quality Outcomes Database was queried for patients who had undergone ACDF or posterior foraminotomy for radiculopathy. To create two highly homogeneous groups, optimal individual matching was performed at a 5:1 ratio between the two groups on 29 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, underlying pathologies, and levels treated). Outcomes of interest were length of stay, reoperations, patient-reported satisfaction, increase in EQ-5D score, and decrease in Neck Disability Index (NDI) scores for arm and neck pain as long as 1 year after surgery. Noninferiority analysis of achieving patient satisfaction and minimal clinically important difference (MCID) in PROs was performed with an accepted risk difference of 5%. RESULTS A total of 7805 eligible patients were identified: 216 of these underwent posterior foraminotomy and were matched to 1080 patients who underwent ACDF. The patients who underwent ACDF had more underlying pathologies, lower EQ-5D scores, and higher NDI and neck pain scores at baseline. Posterior foraminotomy was associated with shorter hospitalization (0.5 vs 0.9 days, p < 0.001). Reoperations within 12 months were significantly more common among the posterior foraminotomy group (4.2% vs 1.9%, p = 0.04). The two groups performed similarly in PROs, with posterior foraminotomy being noninferior to ACDF in achieving MCID in EQ-5D and neck pain scores but also having lower rates of maximal satisfaction at 12 months (North American Spine Society score of 1 achieved by 65.2% posterior foraminotomy patients vs 74.6% of ACDF patients, p = 0.02). CONCLUSIONS The two procedures were found to be offered to different populations, with ACDF being selected for patients with more complicated pathologies and symptoms. After individual matching, posterior foraminotomy was associated with a higher reoperation risk within 1 year after surgery compared to ACDF (4.2% vs 1.9%). In terms of 12-month PROs, posterior foraminotomy was noninferior to ACDF in improving quality of life and neck pain. The two procedures also performed similarly in improving NDI scores and arm pain, but ACDF patients had higher maximal satisfaction rates.

Cervical Disc Arthroplasty for the Treatment of Noncontiguous Cervical Degenerative Disc Disease: Results of Mid‐ to Long‐Term Follow‐up

Article

Full-text available

Sep 2023

Objective The long‐term results of cervical disc arthroplasty (CDA) for noncontiguous cervical degenerative disc disease (CDDD) are still uncertain. Moreover, it is unclear whether CDA delays or avoids the degeneration of the intermediate segment (IS), leading to controversy in the field. Therefore, this study aimed to investigate the mid‐ to long‐term clinical and radiographic outcomes of CDA in treating noncontiguous CDDD and to explore whether the IS degenerated faster after CDA than other non‐surgically treated adjacent segments. Methods We retrospectively analyzed patients with noncontiguous CDDD who underwent CDA in our department between January 2008 and July 2018. The patients were divided into the CDA and hybrid surgery (HS) groups, and clinical and radiographic outcomes were evaluated at routine postoperative intervals. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA), neck disability index (NDI), and visual analogue scale (VAS), while radiographic outcomes included cervical lordosis (CL), C2‐C7 range of motion (ROM), segmental ROM, and disc angle (DA) at the arthroplasty level. Complications were also evaluated.Pre‐ and postoperative values were compared using paired t ‐tests or Wilcoxon rank‐sum tests. Independent Student t ‐tests or Mann–Whitney U tests analyzed continuous data between CDA and HS groups, while chi‐square or Fisher exact tests assessed categorical data. Results Sixty‐four patients with noncontiguous CDDD, with 31 in the CDA group and 33 in the HS group, were evaluated. The mean follow‐up time was over 70 months. The most frequently involved levels were C4/5 and C5/6. Both groups showed significant improvements in JOA, NDI, and VAS values after surgery. Although CL was maintained, the CL in the CDA group was consistently lower than that in the HS group ( p < 0.05). There was a significant decrease in C2‐C7 ROM ( p < 0.05), but at the last follow‐up, the C2‐C7 ROM in the CDA group was greater than that in the HS group ( p < 0.05). At the last follow‐up, 44.3% of arthroplasty levels had developed heterotopic ossification (HO), and 48.45% had developed anterior bone loss (ABL). In addition, adjacent segment degeneration (ASDeg) was observed in the IS (22.7%), superior adjacent segment (20.6%)and inferior adjacent segment (21.9%). Conclusion CDA or CDA combined with fusion are viable treatments for noncontiguous CDDD, with satisfactory outcomes after mid‐to‐long‐term follow‐up. ASDeg is similar in non‐surgical segments after 70 months of follow‐up. ROM of the IS issimilar to preoperative levels, indicating CDA does not increase the risk of IS degeneration.

A comparative study of the effect of facet tropism on the index-level kinematics and biomechanics after artificial cervical disc replacement (ACDR) with Prestige LP, Prodisc-C vivo, and Mobi-C: a finite element study

Article

Full-text available

Oct 2024
J Orthop Surg Res

Introduction Artificial cervical disc replacement (ACDR) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. However, some research suggests that ACDR may redistribute more load onto the facet joints, potentially leading to postoperative axial pain in certain patients. Earlier studies have indicated that facet tropism is prevalent in the lower cervical spine and can significantly increase facet joint pressure. The present study aims to investigate the changes in the biomechanical environment of the cervical spine after ACDR using different prosthese when facet tropism is present. Methods A C2-C7 cervical spine finite element model was created. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level by adjusting the left-side facet. C5/C6 ACDR with Prestige LP, Prodisc-C vivo, and Mobi-C were simulated in all models. A 75 N follower load and 1 N⋅m moment was applied to initiate flexion, extension, lateral bending, and axial rotation, and the range of motions (ROMs), facet contact forces(FCFs), and facet capsule stress were recorded. Results In the presence of facet tropism, all ACDR models exhibited significantly higher FCFs and facet capsule stress compared to the intact model. In the asymmetric model, FCFs on the right side were significantly increased in neutral position, extension, left bending and right rotation, and on both sides in right bending and left rotation compared to the symmetric model. All ACDR model in the presence of facet tropism, exhibited significantly higher facet capsule stresses at all positions compared to the symmetric model. The stress distribution on the facet surface and the capsule ligament in the asymmetrical models was different from that in the symmetrical model. Conclusions The existence of facet tropism could considerably increase FCFs and facet capsule stress after ACDR with Prestige-LP, Prodisc-C Vivo, and Mobi-C. None of the three different designs of implants were able to effectively protect the facet joints in the presence of facet tropism. Research into designing new implants may be needed to improve this situation. Clinical trials are needed to validate the impact of facet tropism.

Optimal Implant Sizing Using Machine Learning Is Associated With Increased Range of Motion After Cervical Disk Arthroplasty

Article

Mar 2024
NEUROSURGERY

Background and objectives: Cervical disk arthroplasty (CDA) offers the advantage of motion preservation in the treatment of focal cervical pathology. At present, implant sizing is performed using subjective tactile feedback and imaging of trial cages. This study aims to construct interpretable machine learning (IML) models to accurately predict postoperative range of motion (ROM) and identify the optimal implant sizes that maximize ROM in patients undergoing CDA. Methods: Adult patients who underwent CDA for single-level disease from 2012 to 2020 were identified. Patient demographics, comorbidities, and outcomes were collected, including symptoms, examination findings, subsidence, and reoperation. Affected disk height, healthy rostral disk height, and implant height were collected at sequential time points. Linear regression and IML models, including bagged regression tree, bagged multivariate adaptive regression spline, and k-nearest neighbors, were used to predict ROM change. Model performance was assessed by calculating the root mean square error (RMSE) between predicted and actual changes in ROM in the validation cohort. Variable importance was assessed using RMSE loss. Area under the curve analyses were performed to identify the ideal implant size cutoffs in predicting improved ROM. Results: Forty-seven patients were included. The average RMSE between predicted and actual ROM was 7.6° (range: 5.8-10.1) in the k-nearest neighbors model, 7.8° (range: 6.5-10.0) in the bagged regression tree model, 7.8° (range: 6.2-10.0) in the bagged multivariate adaptive regression spline model, and 15.8° (range: 14.3-17.5°) in a linear regression model. In the highest-performing IML model, graft size was the most important predictor with RMSE loss of 6.2, followed by age (RMSE loss = 5.9) and preoperative caudal disk height (RMSE loss = 5.8). Implant size at 110% of the normal adjacent disk height was the optimal cutoff associated with improved ROM. Conclusion: IML models can reliably predict change in ROM after CDA within an average of 7.6 degrees of error. Implants sized comparably with the healthy adjacent disk may maximize ROM.

The association of cervical sagittal alignment with anterior bone loss following single-level anterior cervical surgery

Article

Full-text available

Mar 2024

Background Anterior bone loss (ABL) is a common phenomenon after cervical disc replacement (CDR), which can also be observed after anterior cervical discectomy and fusion (ACDF). This study aimed to investigate the incidence and severity of ABL in single-level CDR and ACDF and explore the association of cervical sagittal alignment with ABL. Methods This is a single-center retrospective cohort study. A total of 113 patients treated with CDR and 99 patients treated with ACDF were retrospectively reviewed from January 2014 to December 2018 in West China Hospital. Radiological data were collected at pre-operation, 1 week, 3 months postoperatively, and the last follow-up. The incidence and severity of ABL after both CDR and ACDF were evaluated. Cervical sagittal alignment parameters, including C0–C2 angle, cervical lordosis (CL), C2–C7 sagittal vertical axis (cSVA), T1 slope, functional spinal unit angle, disc angle, and surgical level slope, were evaluated. Results ABL was identified in 75 (66.4%) patients in the CDR group and 57 (57.6%) patients in the ACDF group. There were no significant differences in the incidence, severity, and location of ABL between the ACDF and CDR groups. For patients who underwent ACDF, the proportion of females was significantly higher in the ABL group (64.9% vs. 33.3%, P=0.002), whereas the body mass index (BMI) was significantly lower in the ABL group compared to the non-ABL group (22.72±3.09 vs. 24.60±3.04, P=0.002). No effect of ABL on the short-term clinical outcomes of ACDF and CDR was observed. In the ACDF group, patients with ABL had significantly smaller postoperative CL (11.83°±8.24° vs. 15.25°±8.32°, P=0.04) and cSVA (17.77±10.08 vs. 23.35±9.86 mm, P=0.007). In the CDR group, no significant differences were found in the cervical sagittal parameters between patients with and without ABL (CL: 12.58±8.70 vs. 15.46±8.50, P=0.10; cSVA: 20.95±8.54 vs. 19.40±9.43, P=0.38). Conclusions ABL is common after both CDR and ACDF with comparable incidence and severity. Cervical sagittal alignment was closely related to ABL after ACDF yet had less influence on ABL after CDR.

Predictive Value of Cervical Degenerative Quantitative Scoring System on Postoperative Disc Height Loss After Cervical Disc Replacement

Article

Dec 2023

Study design A retrospective study. Objective In this study, a cervical degenerative quantitative scoring system was used to identify the risk factors for disc height loss after cervical disc replacement (CDR) and to verify their accuracy. Background Disc height loss after CDR is drawing much attention. Preoperative cervical degeneration has been proven related to postoperative disc height loss but lacked quantitative verification. Patients and Methods A total of 160 patients who underwent CDR with the Prestige-LP disc at our hospital between January 2011 and December 2016 were retrospectively reviewed. Disc height loss was defined as a reduction of more than 2 mm from postoperative to the final follow-up. A quantitative scoring system was used to evaluate preoperative degeneration on radiographs. Multivariate logistic regression was applied to determine predictive factors and calculate the logistic regression formula. Moreover, receiver operating characteristic curve analysis was conducted to obtain the optimal cutoff value and the area under the receiver operating characteristic curve [areas under the curve (AUC)]. Results Study subjects had a mean age of 43.51 ± 8.51 years, with a mean follow-up time of 60.14 ± 12.75 months. The overall incidence rate of disc height loss was 65.62%. Multivariate logistic regression analysis showed that endplate sclerosis ( P = 0.000) and low preoperative disc height ( P = 0.000) were independent risk factors for postoperative disc height loss. In addition, the calculated optimal cutoff point was 1 point of endplate sclerosis (AUC = 0.768) and 4.5 mm of preoperative disc height (AUC = 0.795). The regression formula established by multivariate logistic regression analysis was composed of preoperative disc height (odds ratio: 2.995, P = 0.000) and endplate sclerosis (odds ratio: 18.131, P = 0.000), with an AUC of 0.879. Conclusions Our findings suggest that a comprehensive preoperative assessment is essential when patients with apparent endplate sclerosis and low preoperative disc height are being considered for CDR.

Range of Motion After 1, 2 and 3Level Cervical Disc Arthroplasty

Article

Full-text available

Nov 2023

Background Motion of a solid body involves translation and rotation. Few investigations examine the isolated translational and rotational components associated with disc arthroplasty devices. This study investigates single- and multi-level cervical disc arthroplasty with respect to index and adjacent level range of motion. The investigators hypothesized that single- and multilevel cervical disc replacement will lead to comparable or improved motion at implanted and adjacent levels. Methods Seven human cervical spines from C2 to C7 were subjected to displacement-controlled loading in flexion, extension, and lateral bending under intact, 1-Level (C5–C6), 2-Level (C5–C6, C6–C7) and 3-Level (C5–C6, C6–C7, C4–C5) conditions. 3D motions sensors were mounted at C4, C5, and C6. Motion data for translations and rotations at each level for each surgical condition and loading mode were compared to intact conditions. Results 1-Level: The index surgery resulted in statistically increased translations in extension and lateral bending at all levels with statistically increased translation observed in flexion in the superior and inferior levels. In rotation, the index surgeries decreased rotation under flexion, with remaining levels not statistically different to intact conditions. 2-Level A device placed inferiorly resulted in statistically increased translations at all levels in extension with statistically increased translations superior and inferior to the index level in flexion. Lateral bending resulted in increased nonsignificant translations. Rotations were elevated or comparable to the intact level for all loading. 3-Level Translations were statistically increased for all levels in all loading modes while rotations were elevated or were comparable to the intact level for all loading modes and levels. Conclusions Micromotion sensors permitted monitoring and recording of small magnitude angulations and translations using a loading mechanism that did not over constrain cervical segmental motion. Multilevel cervical disc arthroplasty yielded comparable or increased overall motion at the index and adjacent levels compared to intact conditions.

An additively manufactured model for preclinical testing of cervical devices

Article

Full-text available

Oct 2023

Purpose Composite models have become commonplace for the assessment of fixation and stability of total joint replacements; however, there are no comparable models for the cervical spine to evaluate fixation. The goal of this study was to create the framework for a tunable non‐homogeneous model of cervical vertebral body by identifying the relationships between strength, in‐fill density, and lattice structure and creating a final architectural framework for specific strengths to be applied to the model. Methods The range of material properties for cervical spine were identified from literature. Using additive manufacturing software, rectangular prints with three lattice structures, gyroid, triangle, zig‐zag, and a range of in‐fill densities were 3D‐printed. The compressive and shear strengths for all combinations were calculated in the axial and coronal planes. Eleven unique vertebral regions were selected to represent the distribution of density. Each bone density was converted to strength and subsequently correlated to the lattice structure and in‐fill density with the desired material properties. Finally, a complete cervical vertebra model was 3D‐printed to ensure sufficient print quality. Results Materials testing identified a relationship between in‐fill densities and strength for all lattice structures. The axial compressive strength of the gyroid specimens ranged from 1.5 MPa at 10% infill to 31.3 MPa at 100% infill and the triangle structure ranged from 2.7 MPa at 10% infill to 58.4 MPa at 100% infill. Based on these results, a cervical vertebra model was created utilizing cervical cancellous strength values and the corresponding in‐fill density and lattice structure combination. This model was then printed with 11 different in‐fill densities ranging from 33% gyroid to 84% triangle to ensure successful integration of the non‐homogeneous in‐fill densities and lattice structures. Conclusions The findings from this study introduced a framework for using additive manufacturing to create a tunable, customizable biomimetic model of a cervical vertebra.

Treatment of the two‑level degenerative cervical disk diseases based on algorithmic anterior approach: a multicenter prospective study

Article

Full-text available

Sep 2023
NEUROSURG REV

Abstract To analyze the efectiveness of an algorithmic anterior approach to the surgical treatment of patients with two-level cervical degenerative disk disease based on the preoperative clinical and imaging parameters. The study included 244 patients with two-level cervical degenerative disk disease. Three groups of patients were evaluated at 3 neurosurgical centers between 2016–2019. The prospective group (Group I, n=126) consisted of patients who were treated using an algorithm to decide whether they should be treated with a two-level Total Disk replacement (TDR), Anterior Cervical Discectomy and Fusion (ACDF) and hybrid technique. The control group (Group II, n=118) consisted of patients who underwent two-level anterior decompression with TDR, ACDF and hybrid stabilization between 2005–2015. Visual Analogue Scale (VAS) neck pain, VAS upper limbs pain, Neck Disability Index (NDI), SF-36, Macnab and Nurick scales were collected. Perioperative com�plications were identifed. At 2 years of follow up Group I had signifcantly better clinical outcomes based on VAS neck pain score (p=0.02), VAS upper limbs pain (p=0.04), NDI score (p=0.02), SF-36 score (p=0.01), satisfaction with surgery on the Macnab scale (p<0.001) and outcome of surgery based on Nurick scale (p<0.001). Complication rate was lower in Group I, 6.3% compared to 24.6% in Group II, p=0.0001. The algorithmic anterior approach to the surgical treatment of patients with two-level cervical degenerative disk disease resulted in signifcant improvement of functional outcomes and a decrease in complications at a minimum 2 years of follow-up. Keywords Cervical spine · Two-level degenerative disk disease · Total disk replacement · Anterior cervical discectomy and fusion · Hybrid stabilization · Surgical algorithm

Cervical disc arthroplasty for magnetic resonance-evident cervical spondylotic myelopathy: comparison with anterior cervical discectomy and fusion

Article

Sep 2023
Neurosurg Focus

Objective: Anterior cervical discectomy and fusion (ACDF) is a standard surgical approach for cervical spondylotic myelopathy (CSM) caused by disc herniations. Although cervical disc arthroplasty (CDA) has become, in the past decade, a viable alternative to ACDF in selected patients, the differences among patients with CSM treated with CDA and ACDF remain elusive. The effectiveness of motion preservation devices in CSM is also unclear. Methods: Adult patients who underwent 1- or 2-level CDA or ACDF between 2007 and 2021 were retrospectively reviewed. Patients whose preoperative T2-weighted MRI demonstrated increased intramedullary signal intensity (IISI) were included and analyzed for the following: comparison of the length of IISI on pre- and postoperative MR images as well as range of motion (ROM) at the indexed levels between the CDA and ACDF groups. Measurement for clinical outcomes included the visual analog scale (VAS) of the arm and neck, the Neck Disability Index, and modified Japanese Orthopaedic Association scores. Perioperative clinical data were also compared between the two groups. Results: A total of 122 patients were allocated to the CDA group and 108 to the ACDF group, with mean follow-ups of 46.6 and 39.0 months, respectively. Patients in the CDA group were younger than those in the ACDF group (47.64 ± 12.40 vs 61.73 ± 12.25 years, p < 0.001) (mean ± SD). The ACDF group had more 2-level surgery compared to the CDA group (p = 0.002). Both groups had significant regression of IISI on postoperative MRI compared to that of preoperative imaging (CDA: 1.23 ± 0.84 to 0.28 ± 0.39 cm; ACDF: 1.07 ± 0.60 to 0.37 ± 0.42 cm; both p < 0.001). The decrease in the length of IISI was similar between the two groups (p = 0.058). The postoperative ROM was well preserved in the CDA group (superior to ACDF, which yielded minimal ROM postoperatively). Both the CDA and ACDF groups demonstrated improvement in Neck Disability Index and modified Japanese Orthopaedic Association scores at 24 months postoperatively. The CDA group had significant improvements on VAS scores, whereas the improvement did not reach significance for the ACDF group at 24 months postoperatively. Conclusions: Significant shortening of IISI on T2-weighted MRI was demonstrated after both CDA and ACDF. At 24 months postoperatively, all clinical outcomes demonstrated improvement after both strategies, except that the VAS score was not significantly improved for ACDF. Therefore, CDA is a safe and effective option for patients with MR-evident CSM.

Cervical disc arthroplasty with the Baguera C prosthesis: clinical and radiological results of a 10-year follow-up study

Article

Full-text available

Jul 2023
EUR SPINE J

Purpose We evaluated the long-term safety, mobility and complications of cervical total disc arthroplasty with the Baguera ® C prosthesis over 10 years. Methods We included 91 patients treated by arthroplasty for cervical degenerative disc disease. A total of 113 prostheses were implanted (50 one-level, 44 two-level and 19 hybrid constructs). They were assessed for complications, clinically, with NDI and SF-12 questionnaires and by independent radiologists for ROM, HO, disc height and adjacent level degeneration. Results No spontaneous migration, loss of fixation, subsidence, vascular complication or dislocation were observed. The reoperation rate was 1%. About 82.7% of the patients were pain free. About 9.9% were taking occasional grade I painkillers. Motricity and sensitivity were preserved in 98.8% and 96.3%. The NDI showed an average functional disability of 17.58%, 26% lower than preoperatively. The SF-12 scores were close to normal health. The average ROM at the treated level was 7.4°. Motion was preserved in 86.6%. Lack of motion was observed in 13.4%. Grades II and III H0 were present in 53.7% and 31.7%, respectively, Grade IV was present in 13.4%. Motion was preserved in 100% of the grades 0–III. The preoperative adjacent level disc height of 4.3 mm remained stable during all the follow-ups at 4.4 mm and 4.2 mm, respectively, at 5 and 10 years. Conclusions After 10 years, cervical arthroplasty with the Baguera ® C prosthesis presents excellent safety and functional results and low complications. Motion was preserved in 86.6%, with a 7.4° ROM. Although common, HO did not hinder motion. Adjacent disc height preservation confirms some adjacent level degeneration protection.

A Retrospective Evaluation and Review of Radiographic Outcomes for Anterior Cervical Discectomy and Fusion (ACDF) Procedures: Northern Ireland's Experience

Article

Full-text available

May 2023

Introduction Anterior Cervical Discectomy and Fusion (ACDF) is the gold standard treatment for symptomatic cervical spondylosis refractory to analgesic medical management. Currently, there are numerous approaches and devices used; however, there is no single implant that is preferred for this procedure. The aim of this study is to evaluate the radiological outcomes of ACDF procedures performed in the regional spinal surgery centre in Northern Ireland. The results of this study will aid surgical decision-making, specifically with regard to the choice of implant. The implants that will be assessed in this study are the stand-alone polyetheretherketone (PEEK) cage (Cage) and the Zero-profile augmented screw implant (Z-P). Methods A total of 420 ACDF cases were reviewed retrospectively. Following exclusion and inclusion criteria, 233 cases were reviewed. In the Z-P group, there were 117 patients, with 116 in the Cage group. Radiographic assessment was carried out at the pre-operative stage, day one post-operation, and follow-up (> three months). Measured parameters included segmental disc height, segmental Cobb angle, and spondylolisthesis displacement distance. Results Patient characteristic features showed no significant difference between the two groups (p>0.05) and no significant difference in mean follow-up time (p=0.146). The Z-P implant was superior in increasing and maintaining disc height post-operatively (+0.4±0.94mm, 5.20±0.66mm) compared to the Cage (+0.1±1.00mm, 4.40±0.95mm) (p<0.001). Z-P was also more successful in restoring and maintaining cervical lordosis in comparison to the Cage group, as it had a significantly smaller kyphosis incidence (0.85% vs. 34.5%) at follow-up (p<0.001). Conclusions Results of this study show a more advantageous outcome in the Zero-profile group as it restores and maintains both disc height and cervical lordosis; it is also more successful in treating spondylolisthesis. This study advocates cautious endorsement of the use of the Zero-profile implant in ACDF procedures for symptomatic cervical disc disease.

Incidence of Heterotopic Ossification at 10 years After Cervical Disk Replacement: A Systematic Review and Meta-analysis

Article

Full-text available

Apr 2023
SPINE

Study design: Systematic review and meta-analysis. Objective: This study aimed to assess the incidence of heterotopic ossification (HO) 10 years after cervical disc replacement (CDR). Summary of background data: HO is a common complication after CDR and may limit the range of motion (ROM) of the artificial disc. As HO usually progresses slowly, long-term follow-up is required to better understand its incidence. In recent years, the increasing number of original articles reporting 10 year outcomes give us the opportunity to better understand the long-term incidence of HO. Methods: We searched PubMed, Medline, Embase, and Cochrane Library databases to identify eligible studies. The incidence of HO was pooled and subgroup analysis was performed. Meta-regression analyses were conducted to identify factors contributing to heterogeneity. Results: Eleven studies with at least 10 years of follow-up comprising 1,140 patients who underwent CDR were included. The pooled incidence of overall HO was 70% (95% CI: 60-81%) at 10 years postoperatively, 60% (95% CI: 44-75%) at 5 or 6 years postoperatively, and 50% (95% CI: 27-72%) at 1 or 2 years postoperatively. The pooled incidence of severe HO (grade 3 or 4) was 37% (95% CI: 29-45%), and mild HO (grade 1 to 2) was 30% (95% CI: 17-44%) at 10 years of follow-up. Pooled ROM decreased from 8.59° before surgery to 7.40° 10 years after surgery. Subgroup analysis showed that HO incidence differed according to the prosthesis type. Earlier publication was associated with a higher pooled incidence of severe HO in the meta-regression analysis. Conclusion: This is the first meta-analysis providing detailed information on the pooled 10-year incidence of HO after CDR. The incidence ofHO appears to increase with the length of follow-up. Level of evidence: III.

Multilevel cervical disc arthroplasty: a review of optimal surgical management and future directions

Article

Full-text available

Dec 2022

OBJECTIVE Cervical disc arthroplasty (CDA) has been recognized as a popular option for cervical radiculopathy or myelopathy caused by disc problems that require surgery. There have been prospective randomized controlled trials comparing CDA to anterior cervical discectomy and fusion (ACDF) for 1- and 2-level disc herniations. However, the indications for CDA have been extended beyond the strict criteria of these clinical trials after widespread real-world experiences in the past decade. This article provides a bibliometric analysis with a review of the literature to understand the current trends of clinical practice and research on CDA. METHODS The PubMed database was searched using the keywords pertaining to CDA in human studies that were published before August 2022. Analyses of the bibliometrics, including the types of papers, levels of evidence, countries, and the number of disc levels involved were conducted. Moreover, a systematic review of the contents with the emphasis on the current practice of multilevel CDA and complex cervical disc problems was performed. RESULTS A total of 957 articles published during the span of 22 years were analyzed. Nearly one-quarter of the articles (232, 24.2%) were categorized as level I evidence, and 33.0% were categorized as levels I or II. These studies clearly demonstrated the viability and effectiveness of CDA regarding clinical and radiological outcomes, including neurological improvement, maintenance, and preservation of segmental mobility with relatively low risks for several years postoperation. Also, there have been more papers published during the last decade focusing on multilevel CDA and fewer involving the comparison of ACDF. Overall, there was a clustering of CDA papers published from the US and East Asian countries. Based on substantial clinical data of CDA for 1- and 2-level disc diseases, the practice and research of CDA show a trend toward multilevel and complex disease conditions. CONCLUSIONS CDA is an established surgical management procedure for 1- and 2-level cervical disc herniation and spondylosis. The success of motion preservation by CDA—with low rates of complications—has outscored ACDF in patients without deformity. For more than 2-level disc diseases, the surgery shows a trend toward multiple CDA or hybrid ACDF–CDA according to individual evaluation for each level of degeneration.

Anterior surgical treatment for cervical degenerative radiculopathy: a prediction model for non-success

Article

Full-text available

Dec 2022
ACTA NEUROCHIR

Purpose By using data from the Norwegian Registry for Spine Surgery, we wanted to develop and validate prediction models for non-success in patients operated with anterior surgical techniques for cervical degenerative radiculopathy (CDR). Methods This is a multicentre longitudinal study of 2022 patients undergoing CDR surgery and followed for 12 months to find prognostic models for non-success in neck disability and arm pain using multivariable logistic regression analysis. Model performance was evaluated by area under the receiver operating characteristic curve (AUC) and a calibration test. Internal validation by bootstrapping re-sampling with 1000 repetitions was applied to correct for over-optimism. The clinical usefulness of the neck disability model was explored by developing a risk matrix for individual case examples. Results Thirty-eight percent of patients experienced non-success in neck disability and 35% in arm pain. Loss to follow-up was 35% for both groups. Predictors for non-success in neck disability were high physical demands in work, low level of education, pending litigation, previous neck surgery, long duration of arm pain, medium-to-high baseline disability score and presence of anxiety/depression. AUC was 0.78 (95% CI, 0.75, 0.82). For the arm pain model, all predictors for non-success in neck disability, except for anxiety/depression, were found to be significant in addition to foreign mother tongue, smoking and medium-to-high baseline arm pain. AUC was 0.68 (95% CI, 0.64, 0.72). Conclusion The neck disability model showed high discriminative performance, whereas the arm pain model was shown to be acceptable. Based upon the models, individualized risk estimates can be made and applied in shared decision-making with patients referred for surgical assessment.

Prediction of 2-year clinical outcome trajectories in patients undergoing anterior cervical discectomy and fusion for spondylotic radiculopathy

Article

Full-text available

Sep 2022

OBJECTIVE Anterior cervical discectomy and fusion (ACDF) is often described as the gold standard surgical technique for cervical spondylotic radiculopathy. Although outcomes are considered favorable, there is little prognostic evidence to guide patient selection for ACDF. This study aimed to 1) describe the 24-month postoperative trajectories of arm pain, neck pain, and pain-related disability; and 2) identify perioperative prognostic factors that predict trajectories representing poor clinical outcomes. METHODS In this retrospective cohort study, patients with cervical spondylotic radiculopathy who underwent ACDF at 1 of 12 orthopedic or neurological surgery centers were recruited. Potential outcome predictors included demographic, health, clinical, and surgery-related prognostic factors. Surgical outcomes were classified by trajectories of arm pain intensity, neck pain intensity (numeric pain rating scales), and pain-related disability (Neck Disability Index) from before surgery to 24 months postsurgery. Trajectories of postoperative pain and disability were estimated with latent class growth analysis, and prognostic factors associated with poor outcome trajectory were identified with robust Poisson models. RESULTS The authors included data from 352 patients (mean age 50.9 [SD 9.5] years; 43.8% female). The models estimated that 15.5%–23.5% of patients followed a trajectory consistent with a poor clinical outcome. Lower physical and mental health–related quality of life, moderate to severe risk of depression, and longer surgical wait time and procedure time predicted poor postoperative trajectories for all outcomes. Receiving compensation and smoking additionally predicted a poor neck pain outcome. Regular exercise, physiotherapy, and spinal injections before surgery were associated with a lower risk of poor disability outcome. Patients who used daily opioids, those with worse general health, or those who reported predominant neck pain or a history of depression were at greater risk of poor disability outcome. CONCLUSIONS Patients who undergo ACDF for cervical spondylotic radiculopathy experience heterogeneous postoperative trajectories of pain and disability, with 15.5%–23.5% of patients experiencing poor outcomes. Demographic, health, clinical, and surgery-related prognostic factors can predict ACDF outcomes. This information may further assist surgeons with patient selection and with setting realistic expectations. Future studies are needed to replicate and validate these findings prior to confident clinical implementation.

Research protocol: Cervical Arthroplasty Cost Effectiveness Study (CACES): economic evaluation of anterior cervical discectomy with arthroplasty (ACDA) versus anterior cervical discectomy with fusion (ACDF) in the surgical treatment of cervical degenerative disc disease — a randomized controlled trial

Article

Full-text available

Aug 2022
TRIALS

Introduction To date, there is no consensus on which anterior surgical technique is more cost-effective in treating cervical degenerative disc disease (CDDD). The most commonly used surgical treatment for patients with single- or multi-level symptomatic CDDD is anterior cervical discectomy with fusion (ACDF). However, new complaints of radiculopathy and/or myelopathy commonly develop at adjacent levels, also known as clinical adjacent segment pathology (CASP). The extent to which kinematics, surgery-induced fusion, natural history, and progression of disease play a role in the development of CASP remains unclear. Anterior cervical discectomy with arthroplasty (ACDA) is another treatment option that is thought to reduce the incidence of CASP by preserving motion in the operated segment. While ACDA is often discouraged, as the implant costs are higher while the clinical outcomes are similar to ACDF, preventing CASP might be a reason for ACDA to be a more cost-effective technique in the long term. Methods and analysis In this randomized controlled trial, patients will be randomized to receive ACDF or ACDA in a 1:1 ratio. Adult patients with single- or multi-level CDDD and symptoms of radiculopathy and/or myelopathy will be included. The primary outcome is cost-effectiveness and cost-utility of both techniques from a healthcare and societal perspective. Secondary objectives are the differences in clinical and radiological outcomes between the two techniques, as well as the qualitative process surrounding anterior decompression surgery. All outcomes will be measured at baseline and every 6 months until 4 years post-surgery. Discussion High-quality evidence regarding the cost-effectiveness of both ACDA and ACDF is lacking; to date, there are no prospective trials from a societal perspective. Considering the aging of the population and the rising healthcare costs, there is an urgent need for a solid clinical cost-effectiveness trial addressing this question. Trial registration ClinicalTrials.gov NCT04623593. Registered on 29 September 2020.

Is C7-T1 cervical disc replacement a viable technique: A case series

Article

Full-text available

Jul 2022

Introduction Cervical disc replacement (CDR) surgery is well established for the treatment of disc degeneration from C3-C7, but there is little data regarding the safety and efficacy of CDR at the cervicothoracic junction, C7-T1. CDR is an appealing option, in terms of range of motion preservation, symptom relief, and absence of risk for nonunion. Currently, C7-T1 CDR is not approved by the Food and Drug Administration, and the existing literature is limited to two case reports that describe the results of a combined two patients. This series explores whether C7-T1 CDR is a reasonable treatment and alternative to fusion. Methods We present a case series of seven consecutive patients who underwent CDR at C7-T1 by a single surgeon from January to December of 2019. There were five females and two males with an average age of 61.3 ± 6.4 years. Results Average follow up was 18.9 ± 2.5 months. The average postoperative NDI score was 22.6 % ± 14.0. We also recorded qualitative data regarding patient satisfaction and revision surgery status. There was one complication of disc subsidence following three months of complete pain resolution. The six other patients reported being very satisfied with their surgical outcome. Conclusion These seven cases dramatically increase the volume of data in the literature on clinical outcomes and patient satisfaction following CDR at the cervicothoracic junction. Additionally, the heterogeneity of cases shows the effectiveness of this treatment in many real-world cases. A greater volume of cases with longer follow up will be necessary to better establish long-term clinical success.

Classification of three-level hybrid surgery for the treatment of cervical degenerative disc disease: a retrospective study of 108 patients

Article

Full-text available

May 2022
BMC Surg

Abstract Introduction According to the different numbers and locations of cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF), three-level hybrid surgery (HS) has many constructs. The purpose of the present study was to introduce a classification system for three-level HS and compare the two types with each other and with ACDF. Methods A retrospective study was conducted involving patients with three-level cervical degenerative disc disease (CDDD) who underwent ACDF or HS in our hospital between June 2012 and May 2019. According to the different numbers and locations of ACDFs and CDAs, we classified the three-level HS into two types (type I: one-level CDA and two-level ACDF, and type II: two-level CDA and one-level ACDF). The differences of clinical and radiological outcomes were compared with each other and with three-level ACDF. Results A total of 108 patients were analyzed. The Neck Disability Index (NDI) of the ACDF group at 3 months postoperatively was significantly higher than that in the type I and type II groups (p

Biomechanical Analysis of 3-Level Anterior Cervical Discectomy and Fusion Under Physiologic Loads Using a Finite Element Model

Article

Full-text available

May 2022

Objective: Pseudarthrosis and adjacent segment degeneration (ASD) are two common complications after multi-level anterior cervical discectomy and fusion (ACDF). We aim to identify the potential biomechanical factors contributing to pseudarthrosis and ASD following three-level ACDF using a cervical spine finite-element model (FEM). Methods: A validated cervical spine FEM from C2 to C7 was used to study the biomechanical factors in cervical spine intervention. The FEM model was used to simulate a three-level ACDF with intervertebral spacers and anterior cervical plating with screw fixation from C4 to C7. The model was then constrained at the inferior nodes of the T1 vertebra, and physiological loads were applied at the top vertebra. The pure moment load of 2 Nm was applied in flexion, extension, and lateral bending. A follower axial force of 75 N was applied to reproduce the weight of the cranium and muscle force, was applied using standard procedures. The motion-controlled hybrid protocol was utilized to comprehend the adjustments in the spinal biomechanics. Results: Our cervical spine FEM demonstrated that the cranial adjacent level (C3-4) had significantly more increase in range of motion (+90.38%) compared to the caudal adjacent level at C7-T1 (+70.18%) after C4-7 ACDF, indicating that the cranial adjacent level has more compensatory increase in ROM than the caudal adjacent level, potentially predisposing it to earlier ASD. Within the C4-7 ACDF construct, the C6-7 level had the least robust fixation during fixation compared to C4-5 and C5-6, as reflected by the smallest reduction in ROM compared to intact spine (-71.30% vs -76.36% and -77.05%, respectively), which potentially predisposes the C6-7 level to higher risk of pseudarthrosis. Conclusion: Biomechanical analysis of C4-7 ACDF construct using a validated cervical spine FEM indicated that the C3-4 has more compensatory increase in ROM compared to C7-T1, and C6-7 has the least robust fixation under physiological loads. These findings can help spine surgeons to predicate the areas with higher risks of pseudarthrosis and ASD, and thus developing corresponding strategies to mitigate these risks and provide appropriate pre-operative counseling to patients.

Influence of 1-Level Versus 2-Level Cervical Disc Replacements and Disc Prosthesis Design on Motion Outcomes 2-Year Postdisc Arthroplasty in 835 Patients From 4 US IDE Clinical Trials

Article

Mar 2025

Study Design/Setting Analysis of 24-month postoperative flexion-extension range of motion (ROM) data from 1-level and 2-level clinical trials of cervical disc arthroplasty (CDA). Objective To investigate the influence of (a) 1-level versus 2-level implantations, and (b) prosthesis design, on the proportions of reconstructed segments that achieved physiological mobility (5–16 degrees). Summary of Background Data The functional goals of CDA are to restore enough ROM to reduce the risk of accelerated adjacent segment degeneration but also limit excessive motion to obtain a biomechanically stable segment. This motion range is termed “physiological” and is defined as 5–16 degrees based on scientific evidence. Methods We analyzed 24-month post-CDA flexion-extension (FE) ROM data from investigational device exemption studies of artificial disc prostheses approved for both 1-level and 2-level use (Mobi-C, Prestige LP, and Simplify). Only the Prestige LP and Mobi-C trials had data presenting how many implanted levels yielded postoperative ROM of a given degree, and only these 2 discs are included in this analysis. Eight hundred thirty-five patients participated in the 1-level and 2-level clinical trials. We calculated the proportion of implanted levels with postoperative FE-ROM in the following motion ranges: hypomobile (0–4 degrees), physiological (5–16 degrees), and hypermobile (≥17 degrees). Results On average, two-thirds of implanted levels in these clinical trials yielded FE-ROM of 9.5±3.1 degrees (physiological mobility). Twenty-five percent of the levels moved 2.4±1.2 degrees (hypomobility), and 9% had ROM of 19.8±2.9 degrees (hypermobility). Prestige LP disc had significantly fewer patients exhibiting hypermobility at 24 months in both single-level and 2-level cases than the Mobi-C disc ( P <0.01). In 2-level Mobi-C constructs, the superior level was where most of that hypermobility occurred. Conclusions Two-level arthroplasty did not significantly influence the likelihood of achieving post-CDA motion in the physiological range when compared with 1-level CDA ( P =0.58). Prosthesis design did influence segmental mobility in both 1-level and 2-level constructs. Surgeons may choose to use a specific implant depending on whether a more- or less-constrained design would be best in a specific clinical situation.

Disparity in Resource Utilization of motion-sparing Anterior Cervical Spine Surgery: An analysis of NSQIP® and PearlDiver® Database

Article

Feb 2025
SPINE J

Cervical Total Disc Arthroplasty

Chapter

Jan 2022

Biomechanics of Motion Preservation Techniques

Chapter

Jan 2022

History of Spinal Instrumentation

Chapter

Jan 2022

The Impact of Disc Height on Outcomes Following Cervical Disc Replacement: A Systematic Review

Article

Nov 2024

Study Design Systematic review Objective Describe the impact of disc height on outcomes following cervical disc replacement (CDR). Summary of Background Data Implant sizing and positioning may impact outcomes following CDR. Methods A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the EMBASE and PubMed databases. The goal of this review was to assess the impact of postoperative “disc height” on clinical and radiologic outcomes following CDR. Results A total of 12 studies were included in the systematic review. In the literature. “disc height” was assessed using multiple different measures: postoperative disc height (DH; n=4), disc height change (DHC; n=4), degree of disc distraction (DDD; n=2), prosthesis height (PH; n=2), functional spinal unit height (FSUH; n=2), and facet distraction (FD; n=1). DH and DHC were the most common measures studied. DHC was associated with statistically and clinically significant differences in several patient-reported outcomes measures (PROMs). However, DH was not associated with any statistically or clinically significant differences in PROMs. With respect to cervical range of motion (ROM), DHC appeared to demonstrate statistically and clinically relevant differences in some of the studies included in this review, while DH was associated with statistically, but not clinically, significant differences. The majority of studies identified DHC <2 mm as an important cutoff to optimize outcomes. Conclusions “Disc height,” especially as measured by DHC, may be an important intraoperative consideration when selecting implant size during CDR. Maintaining DHC <2 mm may optimize PROMs and ROM. Improving technique and implant sizing may aid in translating ex vivo advantages in implant mobility to in vivo improvements in ROM and PROMs.

Three dimensional-printed artificial disc replacement for single-level cervical spondylosis: a cohort study

Article

Oct 2024

To compare the clinical efficacy of 3D-printed artificial discs with that of ACDF for treating cervical spondylosis. This was a retrospective analysis of 73 patients with single-level cervical spondylosis who met the inclusion criteria between January 2020 and December 2022 at XX Hospital. The patients were divided: 38 patients in the ACDF group and 35 patients in the CADR group. Patient general information, including operation time and intraoperative blood loss, was collected. The clinical effect of the combination therapy was evaluated by the VAS, JOA, and NDI. The radiological effect was evaluated using the ROM test. Ethics No. 201,606,009. The average follow-up times in the ACDF and CADR groups were 28.24 ± 4.65 and 29.11 ± 5.06 months, respectively (P = 0.443). Clinical symptoms (evaluated by VAS, NDI, and JOA) are significantly improved in both the ACDF and CADR groups with similar efficacy. The preoperative ROM of the ACDF group was 40.03 ± 8.79, while that of the CADR group was 42.11 ± 7.98 (P = 0.293). However, the postoperative ROM in the ACDF group was 35.29 ± 7.23, which was lower than that in the CADR group (40.43 ± 6.98) (P = 0.003). Furthermore, only one patient in the ACDF group experienced mild dysphagia after surgery, and the patient recovered within three days. ASD occurred in nine patients in the ACDF group and in two patients in the CADR group (Χ²=4.597, P = 0.032). Compared with ACDF, 3D-printed artificial discs for treating single-level cervical spondylosis have proven to be clinically effective; it associated with less blood loss and a lower incidence of ASD, and maintain a better cervical ROM.

The Impact of Endplate Coverage on Heterotopic Ossification Following Cervical Disc Replacement: A Systematic Review and Meta Analysis

Article

Aug 2024
SPINE

Study Design Systematic review and meta-analysis. Objective Describe the impact of endplate coverage on HO in Cervical disc replacement (CDR). Summary of Background Data CDR is a motion-sparing alternative to anterior cervical discectomy and fusion. However, the high prevalence of heterotopic ossification threatens to diminish range of motion and limit this benefit associated with CDR. Methods A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. EMBASE and PubMed databases were queried. Results were deduplicated and screened. Relevant studies were included. All metrics that were reported in ≥3 studies were aggregated for analysis. SPSS was used to perform the meta-analysis. Results A total of 10 studies were included in the systematic review. Endplate coverage was assessed using a wide variety of measurements, including anteroposterior implant depth (ID), endplate depth (ED), exposed endplate depth (EED), implant depth to endplate depth ratio (ID:ED), EED to ED ratio (EED:ED), implant width (IW) to endplate width (EW) ratio (IW:EW), and the implant area (IA) to endplate area (EA) ratio (IA:EA). No evidence has linked ID (3 studies) to HO. Mixed evidence has linked ID:ED (3/5) and IW:ED (1/2) to HO. All available evidence has linked ED (2), EED (4), EED:ED (2), and IA:EA (1) to HO. In our meta-analysis, ID was not found to be a significant risk factor for HO. However, EED and ID:ED were found to be significant risk factors for HO formation. Conclusions Exposed endplate, especially as assessed by EED and ID:ED, is a significant risk factor for HO. Surgeons should focus on preoperative planning and intraoperative implant selection to maximize endplate coverage. While optimizing technique and implant selection is crucial, improved implant design may also be necessary to ensure that appropriate implant-endplate footprint matching is possible across the anatomic spectrum.

Total disc replacements

Chapter

Jan 2024

Thomas J Joyce

The fragility index and reverse fragility index of FDA investigational device exemption trials in spinal fusion surgery: a systematic review

Article

Full-text available

May 2024
EUR SPINE J

Purpose FDA investigational device exemption (IDE) studies are considered a gold standard of assessing safety and efficacy of novel devices through RCTs. The fragility index (FI) has emerged as a means to assess robustness of statistically significant study results and inversely, the reverse fragility index (RFI) for non-significant differences. Previous authors have defined results as fragile if loss to follow up is greater than the FI or RFI. The aim of this study was to assess the FI, RFI, and robustness of data supplied by IDE studies in spinal surgery. Methods This was a systematic review of the literature. Inclusion criteria included randomized controlled trials with dichotomous outcome measures conducted under IDE guidelines between 2000 and 2023. FI and RFI were calculated through successively changing events to non-events until the outcome changed to non-significance or significance, respectively. The fragility quotient (FQ) and reverse fragility quotient (RFQ) were calculated by dividing the FI and RFI, respectively, by the sample size. Results Thirty-two studies met inclusion criteria with a total of 40 unique outcome measures; 240 outcomes were analyzed. Twenty-six studies reported 96 statistically significant results. The median FI was 6 (IQR: 3-9.25), and patients lost to follow up was greater than the FI in 99.0% (95/96) of results. The average FQ was 0.027. Thirty studies reported 144 statistically insignificant results and a median RFI of 6 (IQR: 4-8). The average RFQ extrapolated was 0.021, and loss to follow up was greater than the RFI in 98.6% (142/144) of results. Conclusions IDE studies in spine surgery are surprisingly fragile given their reputations, large sample sizes, and intent to establish safety in investigational devices. This study found a median FI and RFI of 6. The number of patients lost to follow-up was greater than FIand RFI in 98.8% (237/240) of reported outcomes. FQ and RFQ tell us that changes of two to three patients per hundred can flip the significance of reported outcomes. This is an important reminder of the limitations of RCTs. Analysis of fragility in future studies may help clarify the strength of the relationship between reported data and their conclusions.

‘Armed kyphoplasty’ with posterior stabilization avoids corpectomy in complex thoracolumbar spine fractures: a case series

Article

Full-text available

Jan 2024

Background Complex thoracolumbar fractures require reduction and stabilization. Posterior instrumentation alone and standard cement augmentation may represent undertreatment, while corpectomy has significant morbidity. In a series of unstable thoracolumbar fractures, we assessed the feasibility, safety, and results of ‘armed kyphoplasty’ (AKP) and surgical posterior stabilization (PS). Methods A total of 24 consecutive patients were treated with combined AKP and PS. Minimally invasive and open surgery techniques were used for PS. AKP was performed with C-arm or biplane fluoroscopic guidance, and screws were placed under navigation or fluoroscopic guidance. A postoperative CT scan and standing plain films were obtained. Patients were followed up according to clinical standards. Kyphosis correction (measured with regional Cobb angle), pain (measured with the Numeric Rating Scale), neurological status (measured with Frankel grade) were assessed. Results A total of 25 fractures of neoplastic (40%), traumatic (32%), and osteoporotic (28%) nature were treated. Open surgery and minimally invasive techniques were applied in 16/24 and 8/24 patients, respectively. Decompressive laminectomy was performed in 13 cases. No intraprocedural complications occurred. Two patients (8%) died due to underlying disease complications and three complications (12%) required re-intervention (one surgical site infection, one adjacent fracture, and one screw pull-out) in the first month. The mean Cobb angle was 20.14±6.19° before treatment and 11.66±5.24° after treatment (P<0.0001). No re-fractures occurred at the treated levels. Conclusions Combined AKP and PS is feasible and effective in the treatment of complex thoracolumbar fractures of all etiologies. AKP avoided highly invasive corpectomy. Anterior and posterior support ensured stability, preventing implant failure and re-fracture. The complication rate was low compared with more invasive traditional 360° open surgical approaches.

Ten-Year Outcomes of Cervical Disc Arthroplasty Versus Anterior Cervical Discectomy and Fusion: A Systematic Review With Meta-Analysis

Article

Nov 2023

Study Design A systematic review with meta-analysis of randomized controlled trials and comparative retrospective cohort studies. Objective The purpose of this study is to compare 10-year outcomes of cervical disc arthroplasty with that of anterior cervical discectomy and fusion for the treatment of cervical degenerative disc disease (CDDD). Summary of Background Data ACDF is a gold standard for the treatment of CDDD. However, the loss of motion at the operated level may accelerate adjacent segment disease. The preservation of motion with CDA attempts to prevent this complication of cervical fusion. Short and midterm data reveal comparable results for CDA versus ACDF, however, long-term results are unknown. Methods A systematic review with meta-analysis was performed to determine if CDA had improved outcomes compared to ACDF at 10-year follow-up. PubMed and Web of Science database searches through 2023 were performed to identify randomized controlled trials and comparative retrospective cohort studies involving treatment of one or two-level CDDD. Results Six studies were eligible for analysis. CDA had significantly improved NDI scores, VAS scores for pain, and JOA scores ( P < 0.05), however, none of these met minimal clinically important differences (MCID). CDA had significantly fewer secondary surgeries and adverse events ( P < 0.05), however, these did not meet MCID. There were no significant differences in neurological success. Conclusions We found that significantly fewer secondary surgeries and adverse events were seen after CDA than after ACDF at 10-year follow-up. CDA had statistically, but not clinically, improved NDI, VAS, and JOA scores in comparison to ACDF. CDA was not statistically different from ACDF in terms of successful neurologic outcome.

Mid-term and Long-term Outcomes After Total Cervical Disk Arthroplasty Compared With Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Article

Sep 2023

Study design: A meta-analysis of randomized controlled trials (RCTs). Objective: The aim of this study was to compare mid-term to long-term outcomes of cervical disk arthroplasty (CDA) with those of anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic cervical degenerative disk disease. Summary of background data: After ACDF to treat symptomatic cervical degenerative disk disease, the loss of motion at the index level due to fusion may accelerate adjacent-level disk degeneration. CDA was developed to preserve motion and reduce the risk of adjacent segment degeneration. Early-term to mid-term clinical outcomes from RCTs suggest noninferiority of CDA compared with ACDF, but it remains unclear whether CDA yields better mid-term to long-term outcomes than ACDF. Materials and methods: Two independent reviewers searched PubMed, Embase, and the Cochrane Library for RCTs with at least 60 months of follow-up. The risk ratio or standardized mean difference (and 95% CIs) were calculated for dichotomous or continuous variables, respectively. Results: Eighteen reports of 14 RCTs published in 2014-2023 were included. The pooled analysis demonstrated that the CDA group had a significantly greater improvement in neurological success and Neck Disability Index than the ACDF group. The ACDF group exhibited a significantly better improvement in the Short Form-36 Health Survey Physical Component Summary than the CDA group. Radiographic adjacent segment degeneration was significantly lower in the CDA group at 60- and 84-month follow-ups; at 120-month follow-up, there was no significant difference between the 2 groups. Although the overall rate of secondary surgical procedures was significantly lower in the CDA group, we did not observe any significant difference at 60-month follow-up between the CDA and ACDF group and appreciated statistically significant lower rates of radiographic adjacent segment degeneration, and symptomatic adjacent-level disease requiring surgery at 84-month and 108- to 120-month follow-up. The rate of adverse events and the neck and arm pain scores in the CDA group were not significantly different from those of the ACDF group. Conclusions: In this meta-analysis of 14 RCTs with 5- to 10-year follow-up data, CDA resulted in significantly better neurological success and Neck Disability Index scores and lower rates of radiographic adjacent segment degeneration, secondary surgical procedures, and symptomatic adjacent-level disease requiring surgery than ACDF. ACDF resulted in improved Short Form-36 Health Survey Physical Component Summary scores. However, the CDA and ACDF groups did not exhibit significant differences in overall changes in neck and arm pain scores or rates of adverse events.

Preprint

Full-text available

Oct 2023

Introduction Artificial cervical disc replacement (ACDR) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. However, some research suggests that ACDR may redistribute more load onto the facet joints, potentially leading to postoperative axial pain in certain patients. Earlier studies have indicated that facet tropism is prevalent in the lower cervical spine and can significantly increase facet joint pressure. The present study aims to investigate the changes in the biomechanical environment of the cervical spine after ACDR using different prosthese when facet tropism is present. Methods A C2-C7 cervical spine finite element model was created. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level. C5/C6 ACDR with Prestige LP, Prodisc-C vivo, and Mobi-C were simulated in all models. A 75 N follower load and 1 N⋅m moment was applied to initiate flexion, extension, lateral bending, and axial rotation, and the range of motions (ROMs), facet contact forces(FCFs), and facet capsule stress were recorded. Results In the presence of facet tropism, all ACDR models exhibited significantly higher FCFs and facet capsule stress compared to the intact model. In the asymmetric model, FCFs on the right side were significantly increased in neutral position, extension, left bending and right rotation, and on both sides in right bending and left rotation compared to the symmetric model. All ACDR model in the presence of facet tropism, exhibited significantly higher facet capsule stresses at all positions compared to the symmetric model. The stress distribution on the facet surface and the capsule ligament in the asymmetrical models was different from that in the symmetrical model. Conclusions The existence of facet tropism could considerably increase FCFs and facet capsule stress after ACDR with Prestige-LP, Prodisc-C Vivo, and Mobi-C. None of the three different designs of implants were able to effectively protect the facet joints in the presence of facet tropism. Research into designing new implants may be needed to improve this situation. More attention should be paid to facet tropism when planning surgery and selecting implants.

Emerging Technologies within Spine Surgery

Article

Full-text available

Oct 2023

New innovations within spine surgery continue to propel the field forward. These technologies improve surgeons’ understanding of their patients and allow them to optimize treatment planning both in the operating room and clinic. Additionally, changes in the implants and surgeon practice habits continue to evolve secondary to emerging biomaterials and device design. With ongoing advancements, patients can expect enhanced preoperative decision-making, improved patient outcomes, and better intraoperative execution. Additionally, these changes may decrease many of the most common complications following spine surgery in order to reduce morbidity, mortality, and the need for reoperation. This article reviews some of these technological advancements and how they are projected to impact the field. As the field continues to advance, it is vital that practitioners remain knowledgeable of these changes in order to provide the most effective treatment possible.

Multilevel Cervical Disk Arthroplasty: Moving Beyond Two Levels

Article

Sep 2023

Cervical disk arthroplasty (CDA) is well-studied for 1-level and 2-level cervical pathology. There is an increasing trend towards its utilization for greater than 2-level disease as an alternative to the gold standard, anterior cervical discectomy and fusion (ACDF). The number of high-level, prospective studies or randomized trials regarding multilevel CDA is limited but continues to grow as the procedure gains popularity. In appropriately indicated patients with multilevel disease caused by disk herniations or spondylosis without extensive facet arthropathy, CDA shows promising results. Multilevel CDA should be avoided in patients with prior spinal trauma, significant degenerative spondylolisthesis with translation, arthrodesis without mobility, severely incompetent facet joints, ossification of the posterior longitudinal ligament, or kyphotic deformity. With overall similar risk profiles to ACDF but lower theoretical rates of pseudarthrosis and adjacent segment disease, multilevel CDA has been shown to preserve, or perhaps even increase, preoperative cervical range of motion. There are negligible differences in postoperative neck and arm pain, VAS scores, modified Japanese Orthopaedic Association scores, and Neck Disability Index scores when comparing multilevel CDA and ACDF. Despite current indications for multilevel CDA largely being based on single and 2-level data, careful patient selection is critical. Expansion of indications can be expected as literature continues to emerge regarding outcomes and complications in multilevel CDA, as well as with improvements in prosthesis design.

Combined effect of artificial cervical disc replacement and facet tropism on the index-level facet joints: a finite element study

Preprint

Full-text available

Jun 2023

Objective The purpose of this study was to assess the impact of facet tropism on the facet contact force and facet capsule strain after artificial cervical disc replacement (ACDR). Methods A finite element model was constructed from computed tomography (CT) scans of a 28-year-old male volunteer. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level. C5/C6 ACDR was simulated in all models. A 75 N follower load and 1 N⋅m moment was applied to the odontoid process to initiate flexion, extension, lateral bending, and axial rotation, and the range of motions, facet contact forces, and facet capsule strains were recorded. Results In the severe asymmetrical model, the right-side FCF increased considerably under extension, right bending, and left rotation compared with the symmetrical model after C5/C6 ACDR. The ride-side FCFs of the severe asymmetrical model under extension, right bending, and left rotation were about 1.7, 3.1, and 1.8 times of those of the symmetrical model, respectively. The facet capsule strains of both the moderate and severe asymmetrical models increased significantly compared with those of the symmetrical model after C5/C6 ACDR. The left-side capsule strains of the severe asymmetrical model were 2.1, 2.4, 1.6, and 8.5 times of those of the symmetrical model under left bending, right bending, left rotation, and right rotation, respectively. The right-side capsule strains of the severe asymmetrical model were 6.3, 1.6, 3.7, and 2.2 times of those of the symmetrical model under left bending, right bending, left rotation, and right rotation, respectively. The stress distribution on the facet surface in the asymmetrical models was different from that in the symmetrical model. Conclusions The existence of facet tropism could considerably increase facet contact force and facet capsule strain after ACDR, especially under extension, lateral bending, and rotation. Facet tropism also could result in abnormal stress distribution on the facet joint surface and facet joint capsule. Such abnormality might be a risk factor for post-operative facet joint degeneration progression after ACDR, making facet tropism noteworthy when ACDR was considered as the surgical option.

Observational, Multicenter Study of the Efficacy and Safety of Cervical Disk Arthroplasty With Mobi-C in the Treatment of Cervical Degenerative Disk Disease. Results at 10 years Follow-Up

Article

Nov 2022
SPINE

Background: Cervical disc arthroplasty replacement (CDA) was developed to avoid specific disadvantages of cervical fusion. The purpose of this paper is to provide 10-year follow-up results of an ongoing prospective study after CDA. Methods: 384 patients treated using the Mobi-C (ZimVie, Troyes, France) were included in a prospective multicenter study. Routine clinical and radiological examinations were reported pre and postoperatively with up to 10-year follow-up. Complications and revision surgeries were also documented. Results: at 10 years showed significant improvement in all clinical outcomes (NDI, VAS for arm and neck pain, SF-36 PCS and MCS). Motion at the index level increased significantly over baseline (mean ROM=7.6° vs. 8° at 5 years and 6.0° preoperatively; P<0.001) and 71.3% of the implanted segments remained mobile (ROM>3°). Adjacent discs were also mobile at 10 years with the same mobility as preoperatively. At 10 years, 20.9% of the implanted segments demonstrated no heterotopic ossification (HO). Thirty-four patients (8.9%) experienced 41 adverse events, with or without reoperation during the 5 first years. We found only two additional surgeries after 5 years. We observed an increased percentage of working patients and a decrease in medication consumption. Regarding the overall outcome, 94% of patients were satisfied. Conclusions: Our 10-year results showed significant improvement in all clinical outcomes, with low rates of revision or failure. This experience in patients with long-term follow-up after CDA endorses durable, favorable outcomes in properly selected patients.

Multilevel Cervical Disc Arthroplasty. Safety profile and outcomes of 2 or more levels

Article

Mar 2023
Semin Spine Surg

cTDR and ACDF: Comparison of 30-day Population Comorbidities and Perioperative Complications Using Six Years of ACS NSQIP PUF Data

Article

Oct 2022

Objective ACS-NSQIP PUF data from 2014 through 2019 were used to compare one- and two-level ACDF and cTDR with respect to: patient demographics, comorbidities, adverse events, and 30-day morbidity rates. Methods One- and two-level ACDF and cTDR patients were identified by CPT codes. Demographics, comorbidities, and adverse events were summarized. Unmatched cohorts were compared using Wilcoxon Rank Sum test for continuous variables, Pearson’s Chi Square test for categorical variables, and 30-day morbidity using inverse probability of treatment weighted (IPTW) log-binomial regression. Results ACS-NSQIP 2014 through 2019 PUF datasets represent 4,862,497 unique patients, identifying 13347 one-level, 6933 two-level ACDF, 3114 one-level, and 862 two-level cTDR patient cohorts. Statistically significant differences between cohorts are extensive: age, sex, race, admission status, patient origin, discharge disposition, emergent surgery, surgical specialty, ASA classification, wound class, operative time, hospital LOS, BMI, functional status, smoking, diabetes, dyspnea, COPD, CHF, HTN, renal failure, dialysis, cancer, steroid use, anemia, bleeding disorders, systemic sepsis, and number of concurrent comorbid conditions. IPTW log-binomial models, demonstrated increased risk of DVT/thrombophlebitis, pulmonary embolism, deep incisional SSI, pneumonia, and unplanned return to OR associated with ACDF while increased risk of CVA/stroke with neurological deficit and myocardial infarction associated with cTDR. The composite complications outcome favors cTDR over ACDF for 30-day morbidity. No mortalities occurred within the cTDR cohort. Conclusions Adjusting for demographics and comorbidities; ACDF has a higher average risk of adverse event. When ACDF and cTDR are equipoise, consideration for cTDR may be indicated in populations with higher rates of comorbid conditions.

Safety and Validity of Anterior Cervical Disc Replacement for Single-level Cervical Disc Disease: Initial Two-year Follow-up of the Prospective Observational Post-marketing Surveillance Study for Japanese Patients

Article

Full-text available

Oct 2022
NEUROL MED-CHIR

Anterior cervical disc replacement (ACDR) using cervical artificial disc (CAD) has the advantage of maintaining the range of motion (ROM) at the surgical level, subsequently reducing the postoperative risk of adjacent disc disease. Following the approval for the clinical use in Japan, a post-marketing surveillance (PMS) study was conducted for two different types of CAD, namely, Mobi-C (metal-on-plastic design) and Prestige LP (metal-on-metal design). The objective of this prospective observational multicenter study was to analyze the first 2-year surgical results of the PMS study of 1-level ACDR in Japan. A total of 54 patients were registered (Mobi-C, n = 24, MC group; Prestige LP, n = 30, PLP group). Preoperative neurological assessment revealed radiculopathy in 31 patients (57.4%) and myelopathy in 15 patients (27.8%). Preoperative radiological assessment classified the disease category as disc herniation in 15 patients (27.8%), osteophyte in 6 patients (11.1%), and both in 33 patients (61.1%). The postoperative follow-up rates at 6 weeks, 6 months, 1 year, and 2 years after ACDR were 92.6%, 87.0%, 83.3%, and 79.6%, respectively. In both groups, patients' neurological condition improved significantly after surgery. Radiographic assessment revealed loss of mobility at the surgical level in 9.5% of patients in the MC group and in 9.1% of patients in the PLP group. No secondary surgeries at the initial surgical level and no serious adverse events were observed in either group. The present results suggest that 1-level ACDR is safe, although medium- to long-term follow-up is mandatory to further verify the validity of ACDR for Japanese patients. Fullsize Image

Letter to the Editor Regarding “The Incidence of Adjacent Segment Pathology After Cervical Disc Arthroplasty Compared with Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis of Randomized Clinical Trials”

Article

Aug 2022

Cervical Laminoplasty Versus Posterior Laminectomy and Fusion: Trends in Utilization and Evaluation of Complication and Revision Surgery Rates

Article

May 2022

Introduction: Cervical laminoplasty (LP) and laminectomy with fusion (LF) are common operations used to treat cervical spondylotic myelopathy. Conflicting data exist regarding which operation provides superior patient outcomes while minimizing the risk of complications. This study evaluates the trends of LP compared with LF over the past decade in patients with cervical myelopathy and examines long-term revision rates and complications between the two procedures. Methods: Patients aged 18 years or older who underwent LP or LF for cervical myelopathy from 2010 to 2019 were identified in the PearlDiver Mariner Database. Patients were grouped independently (LP versus fusion) and assessed for association with common medical and surgical complications. The primary outcome was the incidence of LP versus LF for cervical myelopathy over time. Secondary outcomes were revision rates up to 5 years postoperatively and the development of complications attributable to either surgery. Results: In total, 1,420 patients underwent LP and 10,440 patients underwent LF. Rates of LP (10.5% to 13.7%) and LF (86.3% to 89.5%) remained stable, although the number of procedures nearly doubled from 865 in 2010 to 1,525 in 2019. On matched analysis, LP exhibited lower rates of wound complications, surgical site infections, spinal cord injury, dysphagia, cervical kyphosis, limb paralysis, incision and drainage/exploration, implant removal, respiratory failure, renal failure, and sepsis. Revision rates for both procedures at were not different at any time point. Conclusion: From 2010 to 2019, rates of LP have not increased and represent less than 15% of posterior-based myelopathy operations. Up to 5 years of follow-up, there were no differences in revision rates for LP compared with LF; however, LP was associated with fewer postoperative complications than LF. Level of evidence: Level III retrospective cohort study.

Adjacent segment degeneration or disease after cervical total disc replacement: A meta-analysis of randomized controlled trials

Article

Full-text available

Oct 2018
J Orthop Surg Res

Abstract Background Anterior cervical discectomy and fusion (ACDF) has been widely used in cervical spondylosis, but adjacent segment degeneration/disease (ASD) was inevitable. Cervical total disc replacement (TDR) could reduce the stress of adjacent segments and retard ASD in theory, but the superiority has not been determined yet. This analysis aimed that whether TDR was superior to ACDF for decreasing adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis). Methods A meta-analysis was performed according to the guidelines of the Cochrane Collaboration with PubMed, EMBASE, Cochrane Library and CBM (China Biological Medicine) databases. It included randomized controlled trials (RCTs) that reported ASDeg, ASDis, and reoperation on adjacent segments after TDR and ACDF. Two investigators independently selected trials, assessed methodological quality, and evaluated the quality of this meta-analysis using the grades of recommendation, assessment, development, and evaluation (GRADE) approach. Results Eleven studies with 2632 patients were included in the meta-analysis. The overall rate of ASD in TDR group was lower than ACDF group (OR = 0.6; 95% CI [0.38, 0.73]; P

Heterotopic Ossification After Cervical Total Disc Replacement at 7 Years—Prevalence, Progression, Clinical Implications, and Risk Factors

Article

Full-text available

Jun 2018

Background: Heterotopic ossification (HO) is a known risk following cervical total disc replacement (CTDR) surgery, but the cause and effect of HO are not well understood. Reported HO rates vary, and few studies are specifically designed to report HO. The effects on outcomes, and the risk factors for the development of HO have been hypothesized and reported in small-population, retrospective analyses, using univariate statistics. Methods: Posthoc, multiple-phase analysis of radiographic, clinical, and demographic data for CTDR as it relates to HO was performed. HO was radiographically graded for 164 one-level and 225 two-level CTDR patients using the McAfee and Mehren system. Analysis was performed to correlate HO grades to clinical outcomes and to evaluate potential risk factors for the development of HO using demographics and baseline clinical measures. Results: At 7 years, 1-level clinically relevant HO grades were 17.6% grade 3 and 11.1% grade 4. Two-level clinically relevant HO grades, evaluated using the highest patient grade, were 26.6% grade 3 and 10.8% grade 4. Interaction between HO and time revealed significance for neck disability index (NDI; P = .04) and Visual Analog Scale (VAS) neck pain (P = .02). When analyzed at each time point NDI was significant at 48-84 months and VAS neck at 60 months. For predictors 2 analyses were run; odds ratios indicated follow-up visit, male sex, and preoperative VAS neck pain are related to HO development, whereas hazard ratios indicated male sex, obesity, endplate coverage, levels treated, and preoperative VAS neck pain. Conclusions: This is the largest study to report HO rates, and related outcomes and risk factors. To develop an accurate predictive model, further large-scale analyses need to be performed. Based on the results reported here, clinically relevant HO should be more accurately described as motion-restricting HO until a definitive link to outcomes has been established.

Review of long-term outcomes of disc arthroplasty for symptomatic single level cervical degenerative disc disease

Article

Full-text available

Jan 2018

Introduction: Cervical disc arthroplasty (CDA) was developed as an alternative for anterior cervical discectomy and fusion (ACDF) for nerve root decompression. The rationale behind CDA was to help prevent adjacent segment degeneration which potentially may lead to additional surgery. Multiple randomized controlled trials have evaluated a myriad of disc arthroplasty devices over the past 10 years and provided data regarding clinical benefits and safety. Their long-term data, reporting results at 5-10 years, presents the opportunity to comment on the overall efficacy, safety and reported complications of these devices. This report reviews results of the Prestige, proDisc-C, Mobi-C Disc and various other arthroplasty devices and provides an overall report of the longest term available data and comparisons between devices. Areas Covered: This review summarizes previously published articles in a literature search using keywords: ‘cervical disc arthroplasty’, ‘cervical total disc replacement’, ‘anterior cervical decompression and fusion’, ‘anterior cervical arthrodesis’, ‘symptomatic degenerative disc disease’ and commercial names of devices. Expert Commentary: CDA, with the devices reviewed, resulted in favorable outcomes in comparison to ACDF for the treatment of symptomatic cervical degenerative disc disease (DDD) taking in to account the long-term functional recovery, adverse events, development of adjacent segment degeneration and subsequent surgical interventions.

Cervical Disc Arthroplasty: Current Evidence and Real-World Application

Article

Full-text available

Jan 2018
NEUROSURGERY

Cervical total disc replacement (cTDR) is still considered a developing technology, with widespread clinical use beginning in the early 2000s. Despite being relatively new to the marketplace, the literature surrounding cTDR is abundant. We conducted a thorough review of literature published in the United States (US) and outside the US to report the current global state of cTDR research and clinical use. Search criteria were restricted to publications with a clinical patient population, excluding finite element analyses, biomechanical studies, cadaver studies, surgical technique-specific papers, and case studies. US publications mostly encompass the results of the highly controlled Food and Drug Administration Investigational Device Exemption trials. The predominantly level I evidence in the US literature supports the use of cTDR at 1 and 2 surgical levels when compared to anterior cervical discectomy and fusion. In general, the outside the US studies typically have smaller patient populations, are rarely controlled, and include broader surgical indications. Though these studies are of lower levels of evidence, they serve to advance patient indications in the use of cTDR. Complications such as secondary surgery, heterotopic ossification, and adjacent segment degeneration also remain a focus of studies. Other external challenges facing cTDR technology include regulatory restrictions and health economics, both of which are beginning to be addressed. Combined, the evidence for cTDR is robust supporting a variety of clinical indications.

Prospective, randomized multicenter study of cervical arthroplasty versus anterior cervical discectomy and fusion: 5-year results with a metal-on-metal artificial disc

Article

Full-text available

Jan 2018

OBJECTIVE Seven cervical total disc replacement (TDR) devices have received FDA approval since 2006. These devices represent a heterogeneous assortment of implants made from various biomaterials with different biomechanical properties. The majority of these devices are composed of metallic endplates with a polymer core. In this prospective, randomized multicenter study, the authors evaluate the safety and efficacy of a metal-on-metal (MoM) TDR (Kineflex|C) versus anterior cervical discectomy and fusion (ACDF) in the treatment of single-level spondylosis with radiculopathy through a long-term (5-year) follow-up. METHODS An FDA-regulated investigational device exemption (IDE) pivotal trial was conducted at 21 centers across the United States. Standard validated outcome measures including the Neck Disability Index (NDI) and visual analog scale (VAS) for assessing pain were used. Patients were randomized to undergo TDR using the Kineflex|C cervical artificial disc or anterior cervical fusion using structural allograft and an anterior plate. Patients were evaluated preoperatively and at 6 weeks and 3, 6, 12, 24, 36, 48, and 60 months after surgery. Serum ion analysis was performed on a subset of patients randomized to receive the MoM TDR. RESULTS A total of 269 patients were enrolled and randomly assigned to undergo either TDR (136 patients) or ACDF (133 patients). There were no significant differences between the TDR and ACDF groups in terms of operative time, blood loss, or length of hospital stay. In both groups, the mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the 60-month follow-up (both p < 0.01). Similarly, VAS pain scores improved significantly by 6 weeks and remained significantly improved through the 60-month follow-up (both p < 0.01). There were no significant changes in outcomes between the 24- and 60-month follow-ups in either group. Range of motion in the TDR group decreased at 3 months but was significantly greater than the preoperative mean value at the 12- and 24-month follow-ups and remained significantly improved through the 60-month period. There were no significant differences between the 2 groups in terms of reoperation/revision surgery or device-/surgery-related adverse events. The serum ion analysis revealed cobalt and chromium levels significantly lower than the levels that merit monitoring. CONCLUSIONS Cervical TDR with an MoM device is safe and efficacious at the 5-year follow-up. These results from a prospective randomized study support that Kineflex|C TDR as a viable alternative to ACDF in appropriately selected patients with cervical radiculopathy. Clinical trial registration no.: NCT00374413 (clinicaltrials.gov)

Long-term Evaluation of Cervical Disc Arthroplasty with the Mobi-C© Cervical Disc: A Randomized, Prospective, Multicenter Clinical Trial with Seven-Year Follow-up

Article

Full-text available

Nov 2017

Background: Cervical total disc replacement (TDR) is an increasingly accepted procedure for the treatment of symptomatic cervical degenerative disc disease. Multiple Level I evidence clinical trials have established cervical TDR to be a safe and effective procedure in the short-term. The objective of this study is to provide a long-term assessment of TDR versus anterior discectomy and fusion for the treatment of one- and two-level disc disease. Methods: This study was a continuation of a prospective, multicenter, randomized, US FDA IDE clinical trial comparing cervical TDR with the Mobi-C© Cervical Disc versus ACDF through 7 years follow-up. Inclusion criteria included a diagnosis of symptomatic cervical degenerative disc disease at one or two cervical levels. TDR patients were treated using a Mobi-C© artificial disc (Zimmer Biomet, Austin TX, USA). ACDF with allograft and anterior plate was used as a control treatment. Outcome measures were collected preoperatively and postoperatively at 6 weeks, at 3, 6, 12, 18 months, annually through 60 months, and at 84 months. Measured outcomes included Overall success, Neck Disability Index (NDI), VAS neck and arm pain, segmental range of motion (ROM), patient satisfaction, SF-12 MCS/PCS, major complications, and subsequent surgery rate. The primary endpoint was an FDA composite definition of success comprising clinical improvement and an absence of major complications and secondary surgery events. Results: A total of 599 patients were enrolled and treated, with 164 treated with one-level TDR, 225 treated with two-level TDR, 81 treated with one-level ACDF, and 105 treated with two-level ACDF. At seven years, follow-up rates ranged from 73.5% to 84.4% (overall 80.2%).The overall success rates of two level TDR and ACDF patients were 60.8% and 34.2%, respectively (p<0.0001). The overall success rates of one level TDR and ACDF patients were 55.2% and 50%, respectively (p>0.05). Both the single and two level TDR and ACDF groups showed significant improvement from baseline NDI scores, VAS neck and arm pain scores, and SF-12 MCS/PCS scores (p<0.0001). In the single level cohort, there was an increased percentage of TDR patients who reported themselves as "very satisfied" (TDR 90.9% vs ACDF 77.8%; p= 0.028). There was a lower rate of adjacent level secondary surgery in the single level TDR patients (3.7%) versus the ACDF patients (13.6%; p = 0.007).In the two level TDR group, the NDI success rate was significantly greater in the TDR group (TDR: 79.0% vs. ACDF: 58.0%; p=0.001). There was significantly more improvement in NDI change score at 7 years in the TDR patients versus ACDF. The TDR group had a significantly higher rate of patients who were "very satisfied" with their treatment compared to the ACDF group (TDR: 85.9% vs. ACDF: 73.9%). The rate of subsequent surgery at the index level was significantly lower in the TDR group compared to the ACDF group (TDR: 4.4% vs. ACDF: 16.2%; p=0.001). The rate of adjacent level secondary surgery was significantly lower in the two level TDR (4.4%) patients compared to the ACDF (11.3%; p=0.03) patients. In both single and two level cohorts, the percentage of patients with worse NDI (2.5%-3.8% of two level surgeries and 1.2%-2.5% of single level surgeries) or worse neck pain (5%-6.8% of the two level surgeries and 1.3% - 3.8% of the single level surgeries) was strikingly low in both groups but trended lower in the TDR patients. Conclusions: At seven years, the composite success analysis demonstrated clinical superiority of two level TDR over ACDF and non-inferiority of single level TDR versus ACDF. There were lower rates of secondary surgery and higher adjacent level disc survivorship in both groups. Both surgeries were remarkably effective in alleviating pain relative to baseline and the rate of patients with worse disability or neck pain was surprisingly low. Overall, greater than 95% of patients (from both groups) who underwent TDR and 88% of patients who underwent ACDF were "very satisfied" at seven years. The differences in clinical effectiveness of TDR versus ACDF becomes more apparent as treatment increases from one to two levels, indicating a significant benefit for TDR over ACDF for two-level procedures. Ethical standards: The Mobi-C Clinical Trial (ClinicalTrials.gov registration number: NCT00389597) was conducted at 24 sites in the US and was approved by the Institutional Review Board, Research Ethics Committee, or local equivalent of each participating site. Level of evidence: 1.

Indirect meta-analysis comparing clinical outcomes of total cervical disc replacements with fusions for cervical degenerative disc disease

Article

Full-text available

Dec 2017

Anterior cervical discectomy and fusion (ACDF) and total cervical disc replacement (TDR) are considered effective treatments for patients with cervical degenerative disc disease (CDDD). An indirect meta-analysis including 19 randomized controlled trials (5343 patients) was conducted to compare the clinical outcomes of ACDF with TDR. Primary outcomes including functional indicators (NDI [neck disability index] score, neurological success and patient satisfaction), secondary outcomes including surgical outcomes (operation time, blood loss and length of stay) and secondary surgical procedures (secondary surgery at an adjacent level, secondary surgery at the index level, secondary surgery at both levels, removal, reoperation, revision and supplemental fixation) were included in the study. TDR using the Bryan disc was associated with a greater improvement in NDI score than ACDF (MD = −5.574, 95% CrIs [credible intervals] −11.73–−0.219). For neurological success, the Bryan (odds ratio [OR] = 0.559, 95% CrIs 0.323–0.955) and Prestige (OR = 0.474, 95% CrIs 0.319–0.700) discs were superior to ACDF. However, no differences in the patient satisfaction rate were shown between TDR and ACDF. For patients with CDDD, ACDF using allograft and a plate is most effective for determining the surgical parameters. Moreover, TDR using the ProDisc-C, Mobi-C, Prestige and Bryan discs are good choices for improving functional outcomes and reducing secondary surgeries.

Multilevel cervical disc replacement versus multilevel anterior discectomy and fusion: A meta-analysis

Article

Full-text available

Apr 2017

Background Cervical disc replacement (CDR) has been developed as an alternative surgical procedure to anterior cervical discectomy and fusion (ACDF) for the treatment of single-level cervical degenerative disc disease. However, patients with multilevel cervical degenerative disc disease (MCDDD) are common in our clinic. Multilevel CDR is less established compared with multilevel ACDF. This study aims to compare the outcomes and evaluate safety and efficacy of CDR versus ACDF for the treatment of MCDDD. Methods A meta-analysis was performed for articles published up until August 2016. Randomized controlled trials (RCTs) and prospective comparative studies associated with the use of CDR versus ACDF for the treatment of MCDDD were included in the current study. Two reviewers independently screened the articles and data following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Results Seven studies with 702 enrolled patients suffering from MCDDD were retrieved. Patients who underwent CDR had similar operative times, blood loss, Neck Disability Index (NDI) scores, and Visual Analog Scale (VAS) scores compared to patients who underwent ACDF. Patients who underwent CDR had greater overall motion of the cervical spine and the operated levels than patients who underwent ACDF. Patients who underwent CDR also had lower rates of adjacent segment degeneration (ASD). The rate of adverse events was significantly lower in the CDR group. Conclusion CDR may be a safe and effective surgical strategy for the treatment of MCDDD. However, there is insufficient evidence to draw a strong conclusion due to relatively low-quality evidence. Future long-term, multicenter, randomized, and controlled studies are needed to validate the safety and efficacy of multilevel CDR.

SF-36 Physical and Mental Health Summary Scales: a User's Manual

Article

Full-text available

Jan 1993

Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion: A prospective, multicenter investigational device exemption study

Article

Full-text available

Jul 2015
J NEUROSURG-SPINE

OBJECT This study compared the safety and efficacy of treatment with the PRESTIGE LP cervical disc versus a historical control anterior cervical discectomy and fusion (ACDF). METHODS Prospectively collected PRESTIGE LP data from 20 investigational sites were compared with data from 265 historical control ACDF patients in the initial PRESTIGE Cervical Disc IDE study. The 280 investigational patients with single-level cervical disc disease with radiculopathy and/or myelopathy underwent arthroplasty with a low-profile artificial disc. Key safety/efficacy outcomes included Neck Disability Index (NDI), Neck and Arm Pain Numerical Rating Scale scores, 36-Item Short Form Health Survey (SF-36) score, work status, disc height, range of motion, adverse events (AEs), additional surgeries, and neurological status. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at 1.5, 3, 6, 12, and 24 months postoperatively. Predefined Bayesian statistical methods with noninformative priors were used, along with the propensity score technique for controlling confounding factors. Analysis by independent statisticians confirmed initial statistical findings. RESULTS The investigational and control groups were mostly similar demographically. There was no significant difference in blood loss (51.0 ml [investigational] vs 57.1 ml [control]) or hospital stay (0.98 days [investigational] vs 0.95 days [control]). The investigational group had a significantly longer operative time (1.49 hours vs 1.38 hours); 95% Bayesian credible interval of the difference was 0.01–0.21 hours. Significant improvements versus preoperative in NDI, neck/arm pain, SF-36, and neurological status were achieved by 1.5 months in both groups and were sustained at 24 months. Patient follow-up at 24 months was 97.1% for the investigational group and 84.0% for the control group. The mean NDI score improvements versus preoperative exceeded 30 points in both groups at 12 and 24 months. SF-36 Mental Component Summary superiority was established (Bayesian probability 0.993). The mean SF-36 PCS scores improved by 14.3 points in the investigational group and by 11.9 points in the control group from baseline to 24 months postoperatively. Neurological success at 24 months was 93.5% in the investigational group and 83.5% in the control group (probability of superiority ~ 1.00). At 24 months, 12.1% of investigational and 15.5% of control patients had an AE classified as device or device/surgical procedure related; 14 (5.0%) investigational and 21 (7.9%) control patients had a second surgery at the index level. The median return-to-work time for the investigational group was 40 days compared with 60 days for the control group (p = 0.020 after adjusting for preoperative work status and propensity score). Following implantation of the PRESTIGE LP device, the mean angular motion was maintained at 12 months (7.9°) and 24 months (7.5°). At 24 months, 90.0% of investigational and 87.7% of control patients were satisfied with the results of surgery. PRESTIGE LP superiority on overall success (without disc height success), a composite safety/efficacy end point, was strongly supported with 0.994 Bayesian probability. CONCLUSIONS This device maintains mean postoperative segmental motion while providing the potential for biomechanical stability. Investigational patients reported significantly improved clinical outcomes compared with baseline, at least noninferior to ACDF, up to 24 months after surgery.

Cervical Total Disc Replacement is Superior to Anterior Cervical Decompression and Fusion: A Meta-Analysis of Prospective Randomized Controlled Trials

Article

Full-text available

Mar 2015
PLOS ONE

Background: Despite being considered the standard surgical procedure for symptomatic cervical disc disease, anterior cervical decompression and fusion invariably accelerates adjacent segment degeneration. Cervical total disc replacement is a motion-preserving procedure developed as a substitute to fusion. Whether cervical total disc replacement is superior to fusion remains unclear. Methods: We comprehensively searched PubMed, EMBASE, Medline, and the Cochrane Library in accordance with the inclusion criteria to identify possible studies. The retrieved results were last updated on December 12, 2014. We classified the studies as short-term and midterm follow-up. Results: Nineteen randomized controlled trials involving 4516 cases were identified. Compared with anterior cervical decompression and fusion, cervical total disc replacement had better functional outcomes (neck disability index [NDI], NDI success, neurological success, neck pain scores reported on a numerical rating scale [NRS], visual analog scales scores and overall success), greater segmental motion at the index level, fewer adverse events and fewer secondary surgical procedures at the index and adjacent levels in short-term follow-up (P < 0.05). With midterm follow-up, the cervical total disc replacement group indicated superiority in the NDI, neurological success, pain assessment (NRS), and secondary surgical procedures at the index level (P < 0.05). The Short Form 36 (SF-36) and segmental motion at the adjacent level in the short-term follow-up showed no significant difference between the two procedures, as did the secondary surgical procedure rates at the adjacent level with midterm follow-up (P > 0.05). Conclusions: Cervical total disc replacement presented favorable functional outcomes, fewer adverse events, and fewer secondary surgical procedures. The efficacy and safety of cervical total disc replacement are superior to those of fusion. Longer-term, multicenter studies are required for a better evaluation of the long-term efficacy and safety of the two procedures.

Multi-level cervical disc arthroplasty (CDA) versus single-level CDA for the treatment of cervical disc diseases: a meta-analysis

Article

Full-text available

Jun 2014

Purpose: Cervical disc arthroplasty (CDA) was developed to treat cervical degenerated disc diseases with the advantages of preserving the kinematics of the functional spinal unit. However, the safety and reliability of multi-level CDA are still controverted when comparing to the single-level CDA. It has shown unclear benefits in terms of clinical results, functional recovery, heterotopic ossification, and the need for secondary surgical procedures. The purpose of this study is to estimate the effectiveness of multi-level cervical arthroplasty over single-level CDA for the treatment of cervical spondylosis and disc diseases. Methods: To compare the studies of multi-level CDA versus single-level CDA in patients with cervical spondylosis that reported at least one of the following outcomes: functionality, neck pain, arm pain, quality of life, reoperation and incidence of heterotopic ossification, electronic databases (Medline, Embase, Pubmed, Cochrane library, and Cochrane Central Register of Controlled Trials) were searched. No language restrictions were used. Two authors independently assessed the methodological quality of included studies and extracted the relevant data. Results: Out of Eight cohorts that were included in the study, four were prospective cohorts and the other four were retrospective. The results of the meta-analysis indicated that there was no significant difference in neck disability index scores, neck visual analog scale (VAS), arm VAS, morbidity of reoperation, heterotopic ossification, and parameters of living quality when comparing multi-level CDA with single-level CDA at 1 and 2 years follow-up postoperatively (p > 0.05). Conclusions: The meta-analysis revealed that the outcomes and functional recovery of patients performed with multi-level CDA are equivalent to those with single-level CDA, which suggests the multi-level CDA is as effective and safe as single-level invention for the treatment of cervical spondylosis. Nonetheless, more well-designed studies with large groups of patients are needed to provide further evidence for the benefit and reliability of multi-level CDA in the treatment of cervical disc diseases.

Disc prosthesis replacement and interbody fusion in the treatment of degenerative cervical disc disease: Comparative analysis of 176 consecutive cases

Article

Full-text available

Sep 2013
EUR SPINE J

The purpose of this retrospective analysis is to determine whether disc prosthesis replacement can be equivalent or superior compared with the disc interbody fusion. Between January, 2005 and June, 2011 we performed microdiscetomy by the anterior approach in 176 patients. We subdivided the total set of patients into two groups. Group A is made up of 84 patients in whom the prosthetic disc was implanted; Group B is made up of 92 patients in whom disc fusion was performed. In both groups, the radicular pain disappeared and the signs of spinal cord compression improved or remained stable. Patients of Group A required significantly fewer days of hospitalization and shorter absence from work, and had significant lower scores in the Neck Disability Index (NDI) at 12 months. Our experience demonstrates that the use of disc prosthesis is a safe and effective alternative to interbody fusion.

Cervical total disc replacement with the mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: A prospective, randomized, controlled multicenter clinical trial: Clinical article

Article

Full-text available

Sep 2013
J NEUROSURG-SPINE

Object: Cervical total disc replacement (TDR) is intended to treat neurological symptoms and neck pain associated with degeneration of intervertebral discs in the cervical spine. Anterior cervical discectomy and fusion (ACDF) has been the standard treatment for these indications since the procedure was first developed in the 1950s. While TDR has been shown to be a safe and effective alternative to ACDF for treatment of patients with degenerative disc disease (DDD) at a single level of the cervical spine, few studies have focused on the safety and efficacy of TDR for treatment of 2 levels of the cervical spine. The primary objective of this study was to rigorously compare the Mobi-C cervical artificial disc to ACDF for treatment of cervical DDD at 2 contiguous levels of the cervical spine. Methods: This study was a prospective, randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc conducted at 24 centers in the US. The primary clinical outcome was a composite measure of study success at 24 months. The comparative control treatment was ACDF using allograft bone and an anterior plate. A total of 330 patients were enrolled, randomized, and received study surgery. All patients were diagnosed with intractable symptomatic cervical DDD at 2 contiguous levels of the cervical spine between C-3 and C-7. Patients were randomized in a 2:1 ratio (TDR patients to ACDF patients). Results: A total of 225 patients received the Mobi-C TDR device and 105 patients received ACDF. At 24 months only 3.0% of patients were lost to follow-up. On average, patients in both groups showed significant improvements in Neck Disability Index (NDI) score, visual analog scale (VAS) neck pain score, and VAS arm pain score from preoperative baseline to each time point. However, the TDR patients experienced significantly greater improvement than ACDF patients in NDI score at all time points and significantly greater improvement in VAS neck pain score at 6 weeks, and at 3, 6, and 12 months postoperatively. On average, patients in the TDR group also maintained preoperative segmental range of motion at both treated segments immediately postoperatively and throughout the study period of 24 months. The reoperation rate was significantly higher in the ACDF group at 11.4% compared with 3.1% for the TDR group. Furthermore, at 24 months TDR demonstrated statistical superiority over ACDF based on overall study success rates. Conclusions: The results of this study represent the first available Level I clinical evidence in support of cervical arthroplasty at 2 contiguous levels of the cervical spine using the Mobi-C cervical artificial disc. These results continue to support the use of cervical arthroplasty in general, but specifically demonstrate the advantages of 2-level arthroplasty over 2-level ACDF. Clinical trial registration no.: NCT00389597 (ClinicalTrials.gov).

Loading effects of anterior cervical spine fusion on adjacent segments

Article

Full-text available

Nov 2012

Adjacent segment degeneration typically follows anterior cervical spine fusion. However, the primary cause of adjacent segment degeneration remains unknown. Therefore, in order to identify the loading effects that cause adjacent segment degeneration, this study examined the loading effects to superior segments adjacent to fused bone following anterior cervical spine fusion. The C3-C6 cervical spine segments of 12 sheep were examined. Specimens were divided into the following groups: intact spine (group 1); and C5-C6 segments that were fused via cage-instrumented plate fixation (group 2). Specimens were cycled between 20° flexion and 15° extension with a displacement control of 1°/second. The tested parameters included the range of motion (ROM) of each segment, torque and strain on both the body and inferior articular process at the superior segments (C3-C4) adjacent to the fused bone, and the position of the neutral axis of stress at under 20° flexion and 15° extension. Under flexion and Group 2, torque, ROM, and strain on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. Under extension and Group 2, ROM for the fused segment was less than that of Group 1; torque, ROM, and stress on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. These analytical results indicate that the muscles and ligaments require greater force to achieve cervical motion than the intact spine following anterior cervical spine fusion. In addition, ROM and stress on the bodies and facets of the joint segments adjacent to the fused bone were significantly increased. Under flexion, the neutral axis of the stress on the adjacent segment moved backward, and the stress on the bodies of the segments adjacent to the fused bone increased. These comparative results indicate that increased stress on the adjacent segments is caused by stress-shielding effects. Furthermore, increased stress and ROM of the adjacent segments after long-term bone fusion may accelerate degeneration in adjacent segment.

Changes in adjacent-level disc pressure and facet joint force after cervical arthroplasty compared with cervical discectomy and fusion

Article

Full-text available

Aug 2007

The authors of previous in vitro investigations have reported an increase in adjacent-level intradiscal pressures (IDPs) and facet joint stresses following cervical spine fusion. This study was performed to compare adjacent-level IDPs and facet force following arthroplasty with the fusion model. Eighteen human cadaveric cervical spines were tested in the intact state for different modes of motion (extension, flexion, bending, and rotation) up to 2 Nm. The specimens were then divided into three groups: those involving the ProDisc-C cervical artificial disc, Prestige cervical artificial disc, and cervical fusion. They were load tested after application of instrumentation or surgery at the C6-7 level. During the test, IDPs and facet forces were measured at adjacent levels. In arthroplasty-treated specimens, the IDP showed little difference from that of the intact spine at both proximal and distal levels. In fusion-treated specimens, the IDP increased at the posterior anulus fibrosus on extension and at the anterior anulus fibrosus on flexion at the proximal level. At the distal level, the IDP change was not significant. The facet force changes were minimal in flexion, bending, and rotation modes in both arthroplasty- and fusion-treated spines. Significant changes were noted in the extension mode only. In extension, arthroplasty models exhibited significant increases of facet force at the treated level. In the fusion model the facet forces decreased at the treated segment and increased at the adjacent segment. The two artificial discs of the semiconstrained systems maintain adjacent-level IDPs near the preoperative values in all modes of motion, but with respect to facet force pressure tended to increase after arthroplasty.

Ten-year Outcomes of Cervical Disc Replacement With the BRYAN Cervical Disc: Results From a Prospective, Randomized, Controlled Clinical Trial

Article

Oct 2018

Study design: Prospective, randomized multicenter IDE Trial between May 2002 and October 2004. Objective: Report on the 10-year safety and efficacy of BRYAN® cervical disc (CDA). Summary of background data: Cervical disc arthroplasty (CDA) is a potential alternative for anterior cervical decompression and fusion (ACDF) with the hope that maintenance of motion may decrease the likelihood of adjacent segment disease. Methods: This is an analysis of a FDA investigation comparing CDA with ACDF for single level patients. Eligible patients were ≥ 21 years of age with symptomatic cervical disc disease who had failed conservative care. Patients were followed at regular intervals with the current data set at > 10 years. Protocol for overall success: ≥ 15- point improvement in NDI scores, maintenance or improvement in neurologic status, no serious adverse events related to implant or implant/surgical procedure, and no subsequent surgery or intervention classified as "failure." Results: At 10 year follow-up, 128 (CDA) and 104 (ACDF) patients were available for evaluation. Overall success rate was significantly higher for CDA group (81.3% vs. 66.3%; p = 0.005). The rate of second surgeries at adjacent levels was lower for CDA group (9.7% vs. 15.8%; p = 0.146). NDI scores improved significantly in CDA group (Δ38.3 vs. Δ31.1; p = 0.010). VAS neck and arm improved in the CDA group (Δ54.3 vs.Δ49.2; p = 0.119), (Δ58.1 vs. Δ51.6; p = 0.0.60) respectively. 4.1% of CDA patients and 4.9% of ACDF patients had serious adverse events related to study device. Mean angular motions at index level for BRYAN® disc and ACDF were 8.69° and 0.60° respectively. Conclusion: The CDA can preserve and maintain motion in long term compared to ACDF. There was a trend toward fewer adjacent segment surgeries for BRYAN® disc that did not reach significance. Significant improvement in CDA NDI scores may suggest better long-term success for CDA as compared to fusion. Level of evidence: 2.

Long-Term Clinical Experience with Selectively Constrained SECURE-C Cervical Artificial Disc for 1-Level Cervical Disc Disease: Results from Seven-Year Follow-Up of a Prospective, Randomized, Controlled Investigational Device Exemption Clinical Trial

Article

Jun 2018

Background: This research was initiated to compare the long-term clinical safety and effectiveness of the selectively constrained SECURE-C (Globus Medical, Audubon, Pennsylvania) Cervical Artificial Disc to anterior cervical discectomy and fusion (ACDF). To preserve segmental motion, cervical total disc replacement (CTDR) was developed as an alternative to ACDF. Current CTDR designs incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulation with various means of fixation. Methods: Eighteen investigational sites participated in this prospective clinical trial; 380 patients were enrolled and treated in the investigational device exemption study. The first 5 patients treated at each site were nonrandomized and received the investigational SECURE-C device. Patients were randomized, treated surgically, and evaluated postoperatively at 6 weeks, 3 months, 6 months, 12 months, 24 months, and annually thereafter through 84 months postoperative. Results: Overall results for the randomized cohorts demonstrated statistical superiority of the investigational SECURE-C group over the control ACDF group at 84 months postoperative. SECURE-C showed clinically significant improvement in pain and function in terms of neck disability index and visual analog scale scores, and superiority in patient satisfaction was also achieved for patients treated with SECURE-C. Conclusion: Clinical study results indicated that the selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as ACDF. Long-term results from the Post Approval Study demonstrated that SECURE-C is statistically superior to ACDF in terms of overall success and patient satisfaction. Lower rates of subsequent index-level surgeries and device-related adverse events were observed in the SECURE-C group than in the ACDF group. The long-term, level 1 clinical evidence presented here is consistent with other reports supporting the safety and efficacy of cervical arthroplasty, and furthers advocacy for motion preservation as a viable alternative to fusion.

Long-term clinical and radiographic outcomes of the Prestige LP artificial cervical disc replacement at 2 levels: Results from a prospective randomized controlled clinical trial

Article

Apr 2017
J NEUROSURG-SPINE

OBJECTIVE The aim of this study was to assess long-term clinical safety and effectiveness in patients undergoing anterior cervical surgery using the Prestige LP artificial disc replacement (ADR) prosthesis to treat degenerative cervical spine disease at 2 adjacent levels compared with anterior cervical discectomy and fusion (ACDF). METHODS A prospective, randomized, controlled, multicenter FDA-approved clinical trial was conducted at 30 US centers, comparing the low-profile titanium ceramic composite-based Prestige LP ADR (n = 209) at 2 levels with ACDF (n = 188). Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at regular postoperative intervals to 84 months. The primary end point was overall success, a composite variable that included key safety and efficacy considerations. RESULTS At 84 months, the Prestige LP ADR demonstrated statistical superiority over fusion for overall success (observed rate 78.6% vs 62.7%; posterior probability of superiority [PPS] = 99.8%), Neck Disability Index success (87.0% vs 75.6%; PPS = 99.3%), and neurological success (91.6% vs 82.1%; PPS = 99.0%). All other study effectiveness measures were at least noninferior for ADR compared with ACDF. There was no statistically significant difference in the overall rate of implant-related or implant/surgical procedure–related adverse events up to 84 months (26.6% and 27.7%, respectively). However, the Prestige LP group had fewer serious (Grade 3 or 4) implant- or implant/surgical procedure–related adverse events (3.2% vs 7.2%, log hazard ratio [LHR] and 95% Bayesian credible interval [95% BCI] −1.19 [−2.29 to −0.15]). Patients in the Prestige LP group also underwent statistically significantly fewer second surgical procedures at the index levels (4.2%) than the fusion group (14.7%) (LHR −1.29 [95% BCI −2.12 to −0.46]). Angular range of motion at superior- and inferior-treated levels on average was maintained in the Prestige LP ADR group to 84 months. CONCLUSIONS The low-profile artificial cervical disc in this study, Prestige LP, implanted at 2 adjacent levels, maintains improved clinical outcomes and segmental motion 84 months after surgery and is a safe and effective alternative to fusion. Clinical trial registration no.: NCT00637156 (clinicaltrials.gov)

Cervical disc arthroplasty with the Prestige LP disc versus anterior cervical discectomy and fusion, at 2 levels: Results of a prospective, multicenter randomized controlled clinical trial at 24 months

Article

Mar 2017

OBJECTIVE The authors compared the efficacy and safety of arthroplasty using the Prestige LP cervical disc with those of anterior cervical discectomy and fusion (ACDF) for the treatment of degenerative disc disease (DDD) at 2 adjacent levels. METHODS Patients from 30 investigational sites were randomized to 1 of 2 groups: investigational patients (209) underwent arthroplasty using a Prestige LP artificial disc, and control patients (188) underwent ACDF with a cortical ring allograft and anterior cervical plate. Patients were evaluated preoperatively, intraoperatively, and at 1.5, 3, 6, 12, and 24 months postoperatively. Efficacy and safety outcomes were measured according to the Neck Disability Index (NDI), Numeric Rating Scales for neck and arm pain, 36-Item Short-Form Health Survey (SF-36), gait abnormality, disc height, range of motion (investigational) or fusion (control), adverse events (AEs), additional surgeries, and neurological status. Treatment was considered an overall success when all 4 of the following criteria were met: 1) NDI score improvement of ≥ 15 points over the preoperative score, 2) maintenance or improvement in neurological status compared with preoperatively, 3) no serious AE caused by the implant or by the implant and surgical procedure, and 4) no additional surgery (supplemental fixation, revision, or nonelective implant removal). Independent statisticians performed Bayesian statistical analyses. RESULTS The 24-month rates of overall success were 81.4% for the investigational group and 69.4% for the control group. The posterior mean for overall success in the investigational group exceeded that in the control group by 0.112 (95% highest posterior density interval = 0.023 to 0.201) with a posterior probability of 1 for noninferiority and 0.993 for superiority, demonstrating the superiority of the investigational group for overall success. Noninferiority of the investigational group was demonstrated for all individual components of overall success and individual effectiveness end points, except for the SF-36 Mental Component Summary. The investigational group was superior to the control group for NDI success. The proportion of patients experiencing any AE was 93.3% (195/209) in the investigational group and 92.0% (173/188) in the control group, which were not statistically different. The rate of patients who reported any serious AE (Grade 3 or 4) was significantly higher in the control group (90 [47.9%] of 188) than in the investigational group (72 [34.4%] of 209) with a posterior probability of superiority of 0.996. Radiographic success was achieved in 51.0% (100/196) of the investigational patients (maintenance of motion without evidence of bridging bone) and 82.1% (119/145) of the control patients (fusion). At 24 months, heterotopic ossification was identified in 27.8% (55/198) of the superior levels and 36.4% (72/198) of the inferior levels of investigational patients. CONCLUSIONS Arthroplasty with the Prestige LP cervical disc is as effective and safe as ACDF for the treatment of cervical DDD at 2 contiguous levels and is an alternative treatment for intractable radiculopathy or myelopathy at 2 adjacent levels. Clinical trial registration no.: NCT00637156 ( clinicaltrials.gov )

Clinical Outcome of Anterior Cervical Discectomy and Fusion versus Total Disc Replacement – A Meta-Analysis of 2532 Cases

Article

Jan 2016

Purpose: Cervical total disc replacement (TDR) has become an alternative to fusion (ACDF) in the surgical treatment of cervical radiculopathy with the promise of preserving motion in the affected segment and of avoiding accelerated degeneration of the adjacent levels. Nowadays there are numerous prospective, randomised and controlled studies comparing the clinical outcome of patients with both therapeutical options. Since cervical prostheses are much more expensive than cages it is crucial to compare the clinical benefit of both implants on the basis of a larger amount of patient data. Methods: A systematic data base search and study review identified 11 prospective, randomized and controlled studies that compared the clinical outcome after ACDF or TDR using at least the scores of NDI, VAS for neck pain and VAS for arm pain after a follow-up of at least 2 years. 2532 cases were included in the statistical analysis that compared the mean values of the clinical scores. Results: There were no statistically significant difference between the ACDF group and the TDR group in the clinical outcome scores (NDI, VAS neck, VAS arm) 2 years after surgery although some of the included studies found differences. Conclusion: ACDF and cervical TDR generate the same clinical results 2 years after surgery in regard to pain relief. Some of the included studies give proof of a better range of motion and less adjacent level degeneration in the TDR group. Thus, this more expensive option is only indicated in younger patients with soft-disc herniation.

Replacement compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled, multicenter investigational device exemption clinical trial

Article

Mar 2016
J NEUROSURG-SPINE

OBJECTIVE The purpose of this study was to report the outcome of a study of 2-level cervical total disc replacement (Mobi-C) versus anterior cervical discectomy and fusion (ACDF). Although the long-term outcome of single-level disc replacement has been extensively described, there have not been previous reports of the 5-year outcome of 2-level cervical disc replacement. METHODS This study reports the 5-year results of a prospective, randomized US FDA investigational device exemption (IDE) study conducted at 24 centers in patients with 2-level, contiguous, cervical spondylosis. Clinical outcomes at up to 60 months were evaluated, including validated outcome measures, incidence of reoperation, and adverse events. The complete study data and methodology were critically reviewed by 3 independent surgeon authors without affiliation with the IDE study or financial or institutional bias toward the study sponsor. RESULTS A total of 225 patients received the Mobi-C cervical total disc replacement device and 105 patients received ACDF. The Mobi-C and ACDF follow-up rates were 90.7% and 86.7%, respectively (p = 0.39), at 60 months. There was significant improvement in all outcome scores relative to baseline at all time points. The Mobi-C patients had significantly more improvement than ACDF patients in terms of Neck Disability Index score, SF-12 Physical Component Summary, and overall satisfaction with treatment at 60 months. The reoperation rate was significantly lower with Mobi-C (4%) versus ACDF (16%). There were no significant differences in the adverse event rate between groups. CONCLUSIONS Both cervical total disc replacement and ACDF significantly improved general and disease-specific measures compared with baseline. However, there was significantly greater improvement in general and disease-specific outcome measures and a lower rate of reoperation in the 2-level disc replacement patients versus ACDF control patients. Clinical trial registration no. NCT00389597 ( clinicaltrials.gov )

Subsequent surgery rates after cervical total disc replacement using a Mobi-C Cervical Disc Prosthesis versus anterior cervical discectomy and fusion: A prospective randomized clinical trial with 5-year follow-up

Article

Jan 2016
J NEUROSURG-SPINE

OBJECTIVE Cervical total disc replacement (TDR) has been shown in a number of prospective clinical studies to be a viable treatment alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic degenerative disc disease. In addition to preserving motion, evidence suggests that cervical TDR may result in a lower incidence of subsequent surgical intervention than treatment with fusion. The goal of this study was to evaluate subsequent surgery rates up to 5 years in patients treated with TDR or ACDF at 1 or 2 contiguous levels between C-3 and C-7. METHODS This was a prospective, multicenter, randomized, unblinded clinical trial. Patients with symptomatic degenerative disc disease were enrolled to receive 1- or 2-level treatment with either TDR as the investigational device or ACDF as the control treatment. There were 260 patients in the 1-level study (179 TDR and 81 ACDF patients) and 339 patients in the 2-level study (234 TDR and 105 ACDF patients). RESULTS At 5 years, the occurrence of subsequent surgical intervention was significantly higher among ACDF patients for 1-level (TDR, 4.5% [8/179]; ACDF, 17.3% [14/81]; p = 0.0012) and 2-level (TDR, 7.3% [17/234]; ACDF, 21.0% [22/105], p = 0.0007) treatment. The TDR group demonstrated significantly fewer index- and adjacent-level subsequent surgeries in both the 1- and 2-level cohorts. CONCLUSIONS Five-year results showed treatment with cervical TDR to result in a significantly lower rate of subsequent surgical intervention than treatment with ACDF for both 1 and 2 levels of treatment. Clinical trial registration no.: NCT00389597 ( clinicaltrials.gov )

A Guide to Rating Scales and Questionnaires

Article

Jan 2009

Ian Mcdowell

One effect of rising health care costs has been to raise the profile of studies that evaluate care and create a systematic evidence base for therapies and, by extension, for health policies. All clinical trials and evaluative studies require instruments to monitor the outcomes of care in terms of quality of life, disability, pain, mental health, or general well-being. Many measurement tools have been developed, and choosing among them is difficult. This book provides comparative reviews of the quality of leading health measurement instruments and a technical and historical introduction to the field of health measurement, and discusses future directions in the field. This edition reviews over 100 scales, presented in chapters covering physical disability, psychological well-being, anxiety, depression, mental status testing, social health, pain measurement, and quality of life. An introductory chapter describes the theoretical and methodological development of health measures, while a final chapter reviews the current status of the field, indicating areas in which further development is required. Each chapter includes a tabular comparison of the quality of the instruments reviewed, followed by a detailed description of each instrument, covering its purpose and conceptual basis, its reliability and validity, alternative versions and, where possible, a copy of the scale itself. To ensure accuracy, each review has been approved by the original author of each instrument or by an acknowledged expert.

Comparison of Clinical Outcomes of 1- and 2-Level Total Disc Replacement: Four-Year Results From a Prospective, Randomized, Controlled, Multicenter IDE Clinical Trial

Article

Mar 2015
SPINE

A prospective, randomized, multicenter FDA IDE study using total disc replacement as surgical treatment of degenerative disc disease at one or two contiguous levels of the cervical spine. To evaluate the safety and effectiveness of total disc replacement at single or two contiguous levels through 48 months follow-up. Cervical total disc replacement has been shown to be a safe and effective alternative to anterior cervical discectomy and fusion at 24 months. Its motion preserving capabilities may avoid accelerating adjacent segment pathology and thereby lower the rate of associated complications. Patients were randomized in a 2:1 ratio (TDR:ACDF) at 24 sites. Ultimately, 164 patients received TDR at one level and 225 patients received TDR at two contiguous levels. An additional 24 patients (15 one-level, 9 two-level) were treated with TDR as training cases.Outcome measures included NDI, VAS neck and arm pain, SF-12 MCS/PCS, ROM, major complication rates, and secondary surgery rates. Patients received follow-up examinations at regular intervals through 4 years after surgery. Pre-operative characteristics were statistically similar for the one and two-level patient groups. Four year follow up rates were 83.1% (one-level) and 89.0% (two-level). There was no statistically significant difference between one and two-level TDR groups for all clinical outcome measures. Both TDR groups experienced significant improvement at each follow-up when compared to pre-operative scores. One case of migration was reported in the two-level TDR group. A four year post hoc comparison of one and two-level TDR patients concurrently enrolled in a 24 center, FDA IDE clinical trial indicated no statistical differences between groups in clinical outcomes, overall complication rates, and subsequent surgery rates.

Clinical and radiographic analysis of an artificial cervical disc: 7-year follow-up from the Prestige prospective randomized controlled clinical trial

Article

Jul 2014

Object: The authors assess the long-term safety and efficacy of cervical disc replacement with the Prestige Cervical Disc in a prospective, randomized, multicenter trial at 7 years of follow-up. Methods: At 31 investigational sites, 541 patients with single-level cervical disc disease with radiculopathy were randomized to 1 of 2 treatment groups: 276 investigational group patients underwent anterior cervical discectomy and arthroplasty with the Prestige disc, and 265 control group patients underwent anterior cervical discectomy and fusion. Clinical outcomes included Neck Disability Index, the 36-Item Short-Form Health Survey, and neck and arm pain scores. Radiographs were assessed for angle of motion and fusion. Clinical and radiographic outcomes were evaluated preoperatively, intraoperatively, and at 1.5, 3, 6, 12, 24, 36, 60, and 84 months. Results: Of the 541 patients treated, 395 patients (73%; 212 investigational and 183 control patients) completed 7 years of clinical follow-up. Significant improvements achieved by 1.5 months in both groups were sustained at 7 years. In the investigational group, mean Neck Disability Index improvements from preoperative scores were 38.2 and 37.5 at 60 and 84 months, respectively. In the control group, the corresponding means were 33.8 and 31.9. The differences between the investigational and control groups at the 60-month and 84-month periods were significant (p = 0.014 and 0.002, respectively). The overall rates of maintenance or improvement in neurological status in the investigational group were significantly higher: 92.2% and 88.2% at 60 months and 84 months, respectively, compared with 85.7% and 79.7% in the control group (p = 0.017 and 0.011, respectively). At 84 months, the percentage of working patients in the investigational group was 73.9%, and in the control group, 73.1%. Postoperatively, the implant effectively maintained average angular motion of 6.67° at 60 months and 6.75° at 84 months. Cumulative rates for surgery at the index level were lower (p < 0.001) in the investigational group (11 [4.8%] of 276) when compared with the control group (29 [13.7%] of 265) (based on life-table method), and there were statistical differences between the investigational and control groups with specific regard to the rate of subsequent revision and supplemental fixation surgical procedures. Rates for additional surgical procedures that involved adjacent levels were lower in the investigational group than in the control group (11 [4.6%] of 276 vs. 24 [11.9%] of 265, respectively). Conclusions: Cervical disc arthroplasty has the potential for preserving motion at the operated level while providing biomechanical stability and global neck mobility and may result in a reduction in adjacent-segment degeneration. The Prestige Cervical Disc maintains improved clinical outcomes and segmental motion after implantation at 7-year follow-up. Clinical trial registration no. NCT00642876 ( ClinicalTrials.gov ).

Clinical Comparison of 2 Implantation Systems for Single-level Cervical Disk Replacement

Article

Feb 2014
ORTHOPEDICS

The safety and effectiveness of 2 implantation systems for single-segment cervical disk replacement-the Bryan Cervical Disc System (Medtronic Inc, Minneapolis, Minnesota) and the ACCEL system (Medtronic Inc)-have not been clinically compared. A prospective, nonrandomized controlled study in consecutive patients with a minimum 2-year follow-up was performed. Fifty patients with single-level cervical disk degeneration who responded poorly to conservative treatment and underwent Bryan Cervical Disc replacement were involved. Fifty patients were included (24 in group A [Bryan Cervical Disc System] and 26 in group B [ACCEL system]).The patients' visual analog scale scores, Neck Disability Index (NDI) scores, Short Form 36 (SF-36) scores, Odom scores, operative time, blood loss, and complications were compared. Patients' baseline statuses were similar (P>.05). Visual analog scale for neck and arm pain, NDI, and SF-36 were significantly improved postoperatively (P<.05) in both groups, and no clinical differences were found between the groups (P>.05). All Odom scores were better than good. Mean operative time and average blood loss in group A (173±42.5 minutes and 250±159.8 mL, respectively), were both significantly higher than the values in group B (137.5±19.3 minutes and 138.1±86.7 mL, respectively) (P<.05). Complications included intraoperative bleeding, temporary throat discomfort, and slight migration of the prosthesis; there was no significant difference in the total complication rates between the 2 groups (P>.05). The 2 implantation systems displayed equal clinical effectiveness and safety, but the ACCEL system appears to have the advantages of shorter operative time and less blood loss.

Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: An administrative database study

Article

Oct 2013

The natural history of cervical degenerative disease with operative management has not been well described. Even with symptomatic and radiographic evidence of multilevel cervical disease, it is unclear whether single- or multilevel anterior cervical discectomy and fusion (ACDF) procedures produce superior long-term outcomes. To describe national trends in revision rates, complications, and readmission for patients undergoing single and multilevel ACDF. Administrative database study. Between 2006 and 2010, 92,867 patients were recorded for ACDF procedures in the Thomson Reuters MarketScan database. Restricting to patients with >24 months follow-up, 28,777 patients fulfilled our inclusion criteria, of which 12,744 (44%) underwent single-level and 16,033 (56%) underwent multilevel ACDFs. Revision rates and postoperative complications. We used the MarketScan database from 2006 to 2010 to select ACDF procedures based on Current Procedural Terminology coding at inpatient visit. Outcome measures were ascertained using either International Classification of Disease version 9 or Current Procedural Terminology coding. Perioperative complications were more common in multilevel procedures (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.6; p<.0001). Single-level ACDF patients had higher rates of postoperative cervical epidural steroid injections (OR, 0.88; 95% CI, 0.8-1.0; p=.01). Within 30 days after index procedure, the multilevel ACDF cohort was 1.6 times more likely to have undergone revision (OR, 1.6; 95% CI, 1.1-2.4; p=.02). At 2 years follow-up, revision rates were 9.13% in the single-level ACDF cohort and 10.7% for multilevel ACDFs (OR, 1.2; 95% CI, 1.1-1.3; p<.0001). In a multivariate analysis at 2 years follow-up, patients from the multilevel cohort were more likely to have received a surgical revision (OR, 1.1; 95% CI, 1.0-1.2; p=.001), to be readmitted into the hospital for any cause (OR, 1.2; 95% CI, 1.1-1.4; p=.007), and to have suffered complications (OR, 1.3; 95% CI, 1.1-1.5; p=.0003). In this study, we report rates of adverse events and the need for revision surgery in patients undergoing single versus multilevel ACDFs. Increasing number of levels fused at the time of index surgery correlated with increased rate of reoperations. Multilevel ACDF patients requiring additional surgery more often underwent more extensive revision surgeries.

Long-term clinical and radiographic outcomes of cervical disc replacement with the Prestige disc: Results from a prospective randomized controlled clinical trial

Article

Sep 2010
J NEUROSURG-SPINE

The purpose of this study was to determine long-term clinical outcomes in patients undergoing anterior cervical surgery in which a cervical disc prosthesis was used to treat single-level degenerative cervical disc disease. In this prospective, nonblinded study, 541 patients at 32 investigational sites were randomly assigned to 1 of 2 treatment groups. The results of the investigational group, in which patients received the Prestige disc prosthesis, were compared with those of the control group, in which patients underwent an instrumented interbody fusion. Data were collected preoperatively, intraoperatively, and at 1.5, 3, 6, 12, 24, 36, and 60 months postoperatively. To date, 271 patients have completed 5 years of clinical follow-up (144 investigational and 127 control patients). Significant improvements in Neck Disability Index (NDI) scores, Physical Component Summary scores of the 36-Item Short-Form Health Survey, and neck and arm pain scores were achieved by 1.5 months in both groups and sustained at 5 years. The mean NDI improvements from preoperative scores were 35.4, 36.3, and 38.4 at 24, 36, and 60 months, respectively, in the investigational group. The corresponding mean NDI improvements were 33.9, 31.3, and 34.1 in the control group. The intergroup differences at both 36 and 60 months were significant (p = 0.008 and 0.022, respectively). The overall rates of maintenance or improvement in neurological status in the investigational group were 91.6%, 92.8%, and 95.0%, respectively, at 24, 36, and 60 months compared with 83.6%, 83.2%, and 88.9% in the control group (p = 0.006, 0.004, and 0.051, respectively). The implant effectively maintained angular motion, averaging more than 7.3 degrees at 36 months and 6.5 degrees at 60 months after surgery. No implant migration was observed up to 60 months. There were statistically significant differences between the investigational and control groups with regard to the rate of revision and supplemental fixation surgical procedures performed subsequent to the index procedure. Additional surgical procedures for adjacent-segment disease were observed in both treatment groups. Rates for surgery at adjacent levels trended lower in the investigational group (8 patients [11 surgeries]) compared with those in the control group (13 patients [16 surgeries]), but the differences were not statistically significant (p = 0.376). Some of the second surgeries involved both index and adjacent levels. The Prestige disc maintains improved clinical outcomes and segmental motion after implantation at 5-year follow-up.

Comparison of BRYAN Cervical Disc Arthroplasty With Anterior Cervical Decompression and Fusion

Article

Jan 2009
SPINE

A prospective, randomized, multicenter study of surgical treatment of cervical disc disease. To assess the safety and efficacy of cervical disc arthroplasty using a new arthroplasty device at 24-months follow-up. Cervical disc arthroplasty preserves motion in the cervical spine. It is an alternative to fusion after neurologic decompression, whereas anterior decompression and fusion provides a rigorous comparative benchmark of success. We conducted a randomized controlled multicenter clinical trial enrolling patients with cervical disc disease. Ultimately 242 received the investigational device (Bryan Cervical Disc), and 221 patients underwent a single-level anterior cervical discectomy and decompression and fusion as a control group. Patients completed clinical and radiographic follow-up examinations at regular intervals for 2 years after surgery. Analysis of 12- and 24-month postoperative data showed improvement in all clinical outcome measures for both groups; however, 24 months after surgery, the investigational group patients treated with the artificial disc had a statistically greater improvement in the primary outcome variables: Neck disability index score (P = 0.025) and overall success (P = 0.010). With regard to implant- or implant/surgical-procedure-associated serious adverse events, the investigational group had a rate of 1.7% and the control group, 3.2%. There was no statistical difference between the 2 groups with regard to the rate of secondary surgical procedures performed subsequent to the index procedure. Patients who received the artificial cervical disc returned to work nearly 2 weeks earlier than the fusion patients (P = 0.015). Two-year follow-up results indicate that cervical disc arthroplasty is a viable alternative to anterior cervical discectomy and fusion in patients with persistently symptomatic, single-level cervical disc disease.

Results of the prospective, randomized, controlled multicenter Food and Drug Administration investigational device exemption study of the ProDisc-C total disc replacement versus anterior discectomy and fusion for the treatment of 1-level symptomatic cervical disc disease

Article

Sep 2008

Cervical total disc replacement (TDR) is intended to address radicular pain and preserve functional motion between two vertebral bodies in patients with symptomatic cervical disc disease (SCDD). The purpose of this trial is to compare the safety and efficacy of cervical TDR, ProDisc-C (Synthes Spine Company, L.P., West Chester, PA), to anterior cervical discectomy and fusion (ACDF) surgery for the treatment of one-level SCDD between C3 and C7. The study was conducted at 13 sites. A noninferiority design with a 1:1 randomization was used. Two hundred nine patients were randomized and treated (106 ACDF; 103 ProDisc-C). Visual analog scale (VAS) pain and intensity (neck and arm), VAS satisfaction, neck disability index (NDI), neurological exam, device success, adverse event occurrence, and short form-36 (SF-36) standardized questionnaires. A prospective, randomized, controlled clinical trial was performed. Patients were enrolled and treated in accordance with the US Food and Drug Administration (FDA)-approved protocol. Patients were assessed pre- and postoperatively at six weeks, 3, 6, 12, 18, and 24 months. Demographics were similar between the two patient groups (ProDisc-C: 42.1+/-8.4 years, 44.7% males; Fusion: 43.5 +/- 7.1 years, 46.2% males). The most commonly treated level was C5-C6 (ProDisc-C: 56.3%; Fusion=57.5%). NDI and SF-36 scores were significantly less compared with presurgery scores at all follow-up visits for both the treatment groups (p<.0001). VAS neck pain intensity and frequency as well as VAS arm pain intensity and frequency were statistically lower at all follow-up timepoints compared with preoperative levels (p<.0001) but were not different between treatments. Neurologic success (improvement or maintenance) was achieved at 24 months in 90.9% of ProDisc-C and 88.0% of Fusion patients (p=.638). Results show that at 24 months postoperatively, 84.4% of ProDisc-C patients achieved a more than or equal to 4 degrees of motion or maintained motion relative to preoperative baseline at the operated level. There was a statistically significant difference in the number of secondary surgeries with 8.5% of Fusion patients needing a re-operation, revision, or supplemental fixation within the 24 month postoperative period compared with 1.8% of ProDisc-C patients (p=.033). At 24 months, there was a statistically significant difference in medication usage with 89.9% of ProDisc-C patients not on strong narcotics or muscle relaxants, compared with 81.5% of Fusion patients. The results of this clinical trial demonstrate that ProDisc-C is a safe and effective surgical treatment for patients with disabling cervical radiculopathy because of single-level disease. By all primary and secondary measures evaluated, clinical outcomes after ProDisc-C implantation were either equivalent or superior to those same clinical outcomes after Fusion.

The Neck Disability Index: A Study of Reliability and Validity

Article

Oct 1991
J MANIP PHYSIOL THER

Injuries to the cervical spine, especially those involving the soft tissues, represent a significant source of chronic disability. Methods of assessment for such disability, especially those targeted at activities of daily living which are most affected by neck pain, are few in number. A modification of the Oswestry Low Back Pain Index was conducted producing a 10-item scaled questionnaire entitled the Neck Disability Index (NDI). Face validity was ensured through peer-review and patient feedback sessions. Test-retest reliability was conducted on an initial sample of 17 consecutive "whiplash"-injured patients in an outpatient clinic, resulting in good statistical significance (Pearson's r = 0.89, p less than or equal to .05). The alpha coefficients were calculated from a pool of questionnaires completed by 52 such subjects resulting in a total index alpha of 0.80, with all items having individual alpha scores above 0.75. Concurrent validity was assessed in two ways. First, on a smaller subset of 10 patients who completed a course of conservative care, the percentage of change on NDI scores before and after treatment was compared to visual analogue scale scores of percent of perceived improvement in activity levels. These scores correlated at 0.60. Secondly, in a larger subset of 30 subjects, NDI scores were compared to scores on the McGill Pain Questionnaire, with similar moderately high correlations (0.69-0.70). While the sample size of some of the analyses is somewhat small, this study demonstrated that the NDI achieved a high degree of reliability and internal consistency.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior cervical allograft arthrodesis and instrumentation: Multilevel interbody grafting or strut graft reconstruction

Article

Feb 1997

This retrospective study evaluated a single surgeon's series of patients treated by multilevel cervical disc excision (two or three levels), allograft tricortical iliac crest arthrodesis, and anterior instrumentation. The objective of this retrospective study was to compare fusion success and clinical outcome between multilevel Smith-Robinson interbody grafting and tricortical iliac strut graft reconstruction, both supplemented with anterior instrumentation in the cervical spine. The incidence of nonunion for cervical discectomy and fusion varies widely depending on the number of disc levels involved, type of bone graft used, and whether the anterior grafting is supplemented with instrumentation. An alternative to multilevel interbody fusion is corpectomy and strut grafting, in which the incidence of nonunion has been reported to be 27% with autograft and 41% with allograft. Sixty-four consecutive patients who underwent allograft tricortical iliac crest reconstruction and anterior cervical plating were studied. The average follow-up was 39 months. There were 38 patients in the discectomy and interbody grafting group and 26 patients in the corpectomy and strut graft reconstruction group. Pseudoarthrosis occurred in 42% of the anterior cervical interbody fusion patients and 31% of the corpectomy patients. Nonunion in two-level interbody fusions occurred in 36% of the patients as compared to 10% for patients with one-level corpectomies; while 54% of patients with three-level interbody fusions and 44% of patients with two-level corpectomies were noted to have pseudoarthrosis. Higher percentages of nonunion were noted in multilevel interbody grafting than in corpectomy with strut grafting and when more vertebral levels were involved. These radiographic and clinical findings underscore the shortcomings of multilevel anterior cervical allograft reconstruction with plating. Corpectomy may be the preferred method when multiple disc levels are fused. In addition, anterior corpectomy affords decompression of significant osteophytes in a safer and quicker manner. In retrospective studies, there is a need for long-term follow-up before accurate statements can be made about the study population.

Adjacent Level Intradiscal Pressure and Segmental Kinematics Following A Cervical Total Disc Arthroplasty

Article

May 2005
SPINE

In vitro investigation of cervical adjacent level intradiscal pressures (IDPs) following a total disc replacement arthroplasty. The current in vitro study was undertaken to compare adjacent level IDPs and operative level kinematics following a cervical arthroplasty versus an arthrodesis procedure. Clinical data indicate the incidence of symptomatic transition syndrome to be as high as 3% annually following a cervical interbody arthrodesis. Recent developments in the motion preservation technology should, in theory, minimize transition syndrome at the adjacent levels. A total of 10 human cadaveric cervical spines were used in this investigation. Following intact analysis, all specimens were sequentially reconstructed at C5-C6 with 1) total disc replacement (TDR), 2) allograft dowel, and 3) allograft dowel + anterior cervical plate. Testing was performed in displacement control under axial rotation, flexion/extension, and lateral bending loading modes. IDPs were recorded at C4-C5 and C6-C7 whereas peak range of motion (ROM) and NZ were monitored at C5-C6 level. Similar IDPs were recorded between the intact condition and a TDR reconstruction at both adjacent levels under all loading modes (P > 0.05). However, the C4-C5 IDP values produced under flexion/extension testing for both arthrodesis treatments were significantly higher than the means obtained for the intact and disc replacement groups (P < 0.05). Similar intergroup differences were observed at the C6-C7 level; however, statistical significance was achieved during all three loading methods (P < 0.05). C5-C6 ROM analysis indicated a significantly lower ROM for both arthrodesis constructs compared with intact and TDR groups during flexion/extension testing (P < 0.05). No differences were recorded between the intact and the total disc replacement group under any loading conditions (P > 0.05). This is a first study to document that a cervical disc replacement arthroplasty procedure maintains adjacent level IDPs and reconstruction level kinematics near the preoperative values. Consequently, total disc replacement may provide an alternative to conventional surgical management of cervical discogenic pathology decreasing the incidence of symptomatic transition syndrome.

Assessment of adjacent-segment disease in patients treated with cervical fusion or arthroplasty: A prospective 2-year study

Article

Jan 2006

The authors compared the incidence of radiologically documented changes and symptomatic adjacent-level cervical disc disease after single-level discectomy and subsequent cervical fusion or arthroplasty in two independent prospective clinical studies. The patients were treated with the Affinity Anterior Cervical Cage System or the Bryan Artificial Cervical Disc. In each study the patients were required to undergo serial cervical radiography preoperatively and 24 months postoperatively, as well as serial clinical evaluations including documentation of adverse events, neurological status, and results of the 36-item Short Form Health Survey. All serial radiographs were reviewed prior to evaluating the clinical symptoms for development of increasing or new adjacent degenerative disc disease (DDD). Subsequently, the clinical data were analyzed. For various reasons of exclusion, the cases analyzed in the Bryan disc-treated cohort consisted of 74 patients and in the Affinity system-treated cohort there were 158 patients. New anterior osteophyte formation or enlargement, increased narrowing of an interspace, new DDD, and calcification of the anterior longitudinal ligament were the radiological findings indicative of adjacent-level disease. Fusion was associated with a significant increase in x-ray film-based changes of adjacent-disc disease (p = 0.009, odds ratio [OR] 2.44). In the cage fusion series, the incidence of symptomatic adjacent-level DDD was statistically greater than that in the group treated with the artificial disc (p = 0.018), and the patients required a statistically greater number of medical treatments related to episodic symptoms of neck, shoulder, and arm pain attributed to new disc disease (p = 0.001, OR 35.8). In comparing these prospective studies the authors demonstrated that maintaining motion rather than fusion will prevent symptomatic adjacent-disc disease and will decrease adjacent-level radiological indicators of disease at a 24-month postoperative interval.

Multilevel Cervical Fusion and Its Effect on Disc Degeneration and Osteophyte Formation

Article

May 2006
SPINE

The effect of single and double cervical fusion on adjacent segments was investigated using a finite element model of the cervical spine. A healthy spine and a cervical spine with a single and double fusion at different levels were analyzed and evaluated. Disc degeneration and osteophyte formation at the endplates and joints can then be addressed. To evaluate the biomechanical effects of cervical fusion on the cervical spine from C3-C7. The goal was to asses the increase of intervertebral disc and bone stress induced by cervical fusion, the effects of single versus double level fusion, and whether the level in which the fusion is performed, might affect the biomechanics of the spine. Clinical studies have reported that 25% of fusion patients report further degenerative problems within 10 years of fusion. METHODS.: Four finite element models of single fusion at different levels were generated, as well as three additional models for the case of double fusion. The maximum von Mises stresses for anulus, nucleus, and endplates and the motion of the nonfused segments were obtained during lateral bending, flexion, axial torsion, and extension. Each case was compared with the normal cervical spine. Results showed stress increases of up to 96% in the anulus, nucleus, and endplates after fusion. Facet constraining prevents increases in stress during extension. The stresses at all levels tend to be larger for double than for single fusion. The results of this study quantify the significant increase in the level of stresses below and above the fused segments in the cervical spine. A sustained level of this stress can lead to further discs degeneration and osteophytes.

Heterotopic Ossification in Total Cervical Artificial Disc Replacement

Article

Dec 2006
SPINE

Prospective clinical study enrolled in 2 centers (Munich and Liberec) as part of a prospective European multicenter study with ProDisc C (Synthes Inc., Paoli, PA). The first goal of the study was to evaluate the rate of heterotopic ossifications identified with plain radiograph following total cervical disc replacement (TCDR). The second goal was to show whether segmental motion can be preserved, and whether TCDR can provide improvement of the patient's ability to perform activities of daily living as well as a decrease of pain. Only a few reports about the radiologic outcome after TCDR are published so far. Heterotopic ossification is a well-known phenomenon after total hip arthroplasty. The rate of heterotopic ossification following TCDR is unclear. The radiographs of 54 patients (in total, 77 implanted prostheses) were analyzed 1 year after TCDR with a ProDisc C prosthesis. We classified the heterotopic ossification in 5 grades according to a recently published classification system for lumbar total disc replacement. For clinical parameters, the visual analog scale and the Neck Disability Index were evaluated preoperatively and 1 year postoperatively. The Student t test and Wilcoxon test were used for statistical analysis. In 26 treated segments (33.8%), no heterotopic ossification was detectable. Grade 1 ossifications were present in 6 levels (7.8%). A total of 30 segments (39.0%) showed grade 2 ossifications. Heterotopic ossifications that led to restrictions of the range of motion were present in 8 cases (10.4%). One year postoperatively, 7 cases (9.1%) had a spontaneous fusion of the treated segment. The clinical parameters improved significantly and were similar to previous reports about TCDR. Only 33.8% of the patients did not show any signs of heterotopic ossification, and the rate of spontaneous fusion after TCDR 1 year after surgery was unexpectedly high. There were 49.4% of the patients with grade 2-3 ossification, which lets us suspect an even higher rate of spontaneous fusion after long-term follow-ups. Motion preservation after TCDR is only guaranteed if spontaneous fusion can be prevented. Thus, mobility of the implanted segments needs to be further studied.

Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: A randomized controlled clinical trial

Article

Apr 2007

The authors report the results of a prospective randomized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion (ACDF) in patients treated for symptomatic single-level cervical degenerative disc disease (DDD). Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly assigned to one of two treatment groups: 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System (Medtronic Sofamor Danek); 265 patients in the control group underwent decompressive ACDF. Eighty percent of the arthroplasty-treated patients (223 of 276) and 75% of the control patients (198 of 265) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery. Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group. The arthroplasty group also had a statistically significant higher rate of neurological success (p = 0.005) as well as a lower rate of secondary revision surgeries (p = 0.0277) and supplemental fixation (p = 0.0031). The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months, as was relief of neck pain. The patients in the investigational group returned to work 16 days sooner than those in the control group, and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well (p = 0.0492, log-rank test). The cervical disc implant maintained segmental sagittal angular motion averaging more than 7 degrees. In the investigational group, there were no cases of implant failure or migration. The PRESTIGE ST Cervical Disc System maintained physiological segmental motion at 24 months after implantation and was associated with improved neurological success, improved clinical outcomes, and a reduced rate of secondary surgeries compared with ACDF.

Clinical outcome of anterior cervical discectomy and fusion versus total disc replacement—a meta-analysis of 2532 cases

Jan 2016
14

Koenig

The effect of Mobi-C cervical total disc replacement versus ACDF in symptomatic degenerative disc disease: a meta-analysis of randomized controlled trials

Jan 2018
2932

W Xiang
L Shi
C Jiang
Y Tang
L Jiang
Xiang W

Xiang W, Shi L, Jiang C, Tang Y, Jiang L: The effect of Mobi-C cervical total disc replacement versus ACDF in symptomatic degenerative disc disease: a meta-analysis of randomized controlled trials. Int J Clin Exp Med 11:2932-2939, 2018

Heterotopic ossification after cervical total disc replacement at 7 years-prevalence, progression, clinical implications, and risk factors

Jan 2018
352-361

P D Nunley
D A Cavanaugh
E J Kerr
Iii
P A Utter
P G Campbell
K A Frank

Nunley PD, Cavanaugh DA, Kerr EJ III, Utter PA, Campbell PG, Frank KA, et al: Heterotopic ossification after cervical total disc replacement at 7 years-prevalence, progression, clinical implications, and risk factors. Int J Spine Surg 12:352-361, 2018

Jan 2009
275

D Murrey
M Janssen
R Delamarter
J Goldstein
J Zigler
B Tay
Murrey D

Multi-level cervical disc arthroplasty (CDA) versus single-level CDA for the treatment of cervical disc diseases: a meta-analysis

Jan 2015
101

H Zhao
L Cheng
Y Hou
Y Liu
B Liu
J J Mundra
Zhao H

Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial: clinical article

Jan 2013
532

R J Davis
K D Kim
M S Hisey
G A Hoffman
H W Bae
S E Gaede
Davis RJ

Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial

Jan 2009
101

J G Heller
R C Sasso
S M Papadopoulos
P A Anderson
R G Fessler
R J Hacker
Heller JG

Two-level cervical disc arthroplasty versus anterior cervical discectomy and fusion: 10-year outcomes of a prospective, randomized investigational device exemption clinical trial

Abstract

No full-text available

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