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One-Level Versus 2-Level Treatment With Cervical Disc Arthroplasty or Fusion: Outcomes Up to 7 Years
Abstract
Background:
Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) have been used to treat degenerative disc disease at single as well as multiple cervical levels. This study compares the safety and efficacy of 1-level versus 2-level CDA and ACDF.
Methods:
In total, 545 and 397 patients with degenerative disc disease were studied in 1-level and 2-level Food and Drug Administration (FDA)-approved clinical trials, respectively: CDA (n = 280 and 209), ACDF (n = 265 and 188). Data from these studies were used to compare 1- versus 2-level procedures: the propensity score method was used to adjust for potential confounding effects, and adjusted mean outcome safety and efficacy scores at 2 and 7 years postsurgery were compared between 1-level and 2-level procedures within treatment type.
Results:
One-level and 2-level procedures had similar rates of improvement in overall success and patient-reported outcomes scores for both CDA and ACDF. There were no statistical differences in rates of implant-related adverse events (AEs) or serious implant-related AEs between 1-level and 2-level CDA. The 7-year rate of implant-related AEs was higher for 2-level than 1-level ACDF (27.7% vs 18.9%, P ≤ .036), though the rates of serious implant-related AEs between ACDF groups did not differ significantly. Secondary surgery rates were not statistically different between 1-level and 2-level procedures (CDA or ACDF) at the index or adjacent levels at 2 or 7 years. Grade IV heterotopic ossification at 7 years was reported in 4.6% of 1-level CDA patients and 8.6%/7.3% at the superior/inferior levels, respectively, of 2-level CDA patients.
Conclusions:
One- and 2-level CDA appear equally safe and effective in the treatment of cervical degenerative disc disease. Two-level ACDF appears to be as effective as 1-level ACDF but with a higher rate of some AEs at long-term follow-up.
Level of evidence:
2.
Clinical trials:
clinicaltrials.gov: NCT00667459, NCT00642876, and NCT00637156.
... Among retrospective studies, the rate of pseudarthrosis ranged from 0.45% to 31% with a pooled incidence of 3.8% (n = 2048). Among studies reporting rates of pseudarthrosis requiring reoperation, [1][2][3][6][7][8][9][10]13,16,17,24,28,29,34,35,37,44,45] the incidence was Contd... [13] Retrospective study 321 ...
... [33] Adjacent segment disease We identified seven prospective studies [14,[16][17][18]37,38,46] and 11 retrospective studies. [9,15,24,27,30,31,34,39,42,44,47] Overall, the rates of adjacent segment disease (ASD), inclusive of radiographic cases, symptomatic cases, and those requiring [16] Prospective study 90 Cage with integrated fixation ...
... Among retrospective studies (n = 3595), the rate of graft of hardware failure ranged from 0% to 24.6% with a pooled incidence of 1.5%. Among studies reporting rates of reoperation, [6,13,14,16,17,24,29,38,44,51] (n = 1117), the incidence of hardware failure leading to surgical revision ranged from 0.3% to 10.7% with a pooled incidence of 2.2%. ...
Background
Anterior cervical discectomy and fusion (ACDF) is one of the most frequently performed cervical surgeries in the world, yet there have been several reported complications.
Objective
To determine the actual incidence of complications related to ACDF as well as any risk variables that may have been identified in earlier research.
Methods
To evaluate the origin, presentation, natural history, and management of the risks and the complications, we conducted a thorough assessment of the pertinent literature. An evaluation of clinical trials and case studies of patients who experienced one or more complications following ACDF surgery was done using a PubMed, Cochrane Library, and Google Scholar search. Studies involving adult human subjects that were written in the English language and published between 2012 and 2022 were included in the search. The search yielded 79 studies meeting our criteria.
Results
The overall rates of complications were as follows: Dysphagia 7.9%, psudarthrosis 5.8%, adjacent segment disease (ASD) 8.8%, esophageal perforations (EPs) 0.5%, graft or hardware failure 2.2%, infection 0.3%, recurrent laryngeal nerve palsy 1.7%, cerebrospinal fluid leak 0.8%, Horner syndrome 0.5%, hematoma 0.8%, and C5 palsy 1.9%.
Conclusion
Results showed that dysphagia was a common postoperative sequelae with bone morphogenetic protein use and a higher number of surgical levels being the major risk factors. Pseudarthrosis rates varied depending on the factors such as asymptomatic radiographic graft sinking, neck pain, or radiculopathy necessitating revision surgery. The incidence of ASD indicated no data to support anterior cervical plating as more effective than standalone ACDF. EP was rare but frequently fatal, with no correlation found between patient age, sex, body mass index, operation time, or number of levels.
... Cervical disc arthroplasty (CDA)/total disc replacement (TDR) were primarily devised to preserve range of motion (ROM) and, thus, lower the incidence of adjacent segment Table 1]. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Further, for carefully selected patients (i.e. without direct contraindications for placing these devices), our literature review focused on whether CDA/ TDR showed a "lack of inferiority"/occasional superiority, comparable safety/efficacy, and outcomes vs. anterior cervical diskectomy/fusion (ACDF) [ Table 1]. ...
... without direct contraindications for placing these devices), our literature review focused on whether CDA/ TDR showed a "lack of inferiority"/occasional superiority, comparable safety/efficacy, and outcomes vs. anterior cervical diskectomy/fusion (ACDF) [ Table 1]. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Multiple Direct Indications and Contraindications to Performing Cervical CDA/TDR e indications for performing cervical CDA/TDR taken from the North American Spine Society (NASS) Coverage Policy Recommendations: Artificial Cervical Disc Replacement (i.e. revised 11/2015) included; "Radiculopathy related to nerve root compression from 1-2 level degenerative disease (either herniated disc or spondylotic osteophyte) from C3-C4 to C6-C7 refractory to…non-operative management", or "Myelopathy or myeloradiculopathy related to central spinal stenosis from 1-2 level degenerative disease (either herniated disc or spondylotic osteophyte) from C3-C4-C6-C7 with or without neck pain" [ Table 1]. ...
... [9] Additonal studies included stenosis and scoliosis amongst other factors [ Table 1]. [1][2][3][4][5][6][7][8][10][11][12][13][14] Postoperative Dynamic X-rays Confirm Increased Postoperative ROM Following CDA/TDR v ACDF Several studies documented an increased ROM following CDA/TDR vs. ACDF [ Table 1]. [ 1]. [6] CDA/TDR patients exhibited greater improvement in their range of motion (ROM) and sagittal alignment, and better maintained postoperative disc height, and overall improvement in their functional spinal units (FSU). ...
Background
We performed a focused review to determine the “non-inferiority”, potential superiority, and relative safety/efficacy for performing cervical disc arthroplasty (CDA)/total disc replacement (TDR) in carefully selected patients vs. anterior cervical diskectomy/fusion (ACDF). Notably, CDA/TDR were devised to preserve adjacent level range of motion (ROM), reduce the incidence of adjacent segment degeneration (ASD), and the need for secondary ASD surgery.
Methods
We compared the incidence of ASD, reoperations for ASD, safety/efficacy, and outcomes for cervical CDA/TDR vs. ACDF. Indications, based upon the North American Spine Society (NASS) Coverage Policy Recommendations (Cervical Artificial Disc Replacement Revised 11/2015 and other studies) included the presence of radiculopathy or myelopathy/myeloradiculopathy at 1-2 levels between C3-C7 with/without neck pain. Contraindications for CDA/TDR procedures as quoted from the NASS Recommendations (i.e. cited above) included the presence of; “Infection…”, “Osteoporosis and Osteopenia”, “Instability…”, “Sensitivity or Allergy to Implant Materials”, “Severe Spondylosis…”, “Severe Facet Joint Arthropathy…”, “Ankylosing Spondylitis” (AS), “Rheumatoid Arthritis (RA), Previous Fracture…”, “Ossification of the Posterior Longitudinal Ligament (OPLL)”, and “Malignancy…”. Other sources also included spinal stenosis and scoliosis.
Results
Cervical CDA/TDR studies in the appropriately selected patient population showed no inferiority/ occasionally superiority, reduced the incidence of ASD/need for secondary ASD surgery, and demonstrated comparable safety/efficacy vs. ACDF.
Conclusion
Cervical CDA/TDR studies performed in appropriately selected patients showed a “lack of inferiority”, occasional superiority, a reduction in the incidence of ASD, and ASD reoperation rates, plus comparable safety/efficacy vs. ACDF.
... Due to fusion, the incidence of adjacent segment degeneration is reported to be 2.9%, but it can increase to as high as 25.6% after a ten-year follow-up (Hilibrand et al., 1999). Therefore, in order to maintain the range of motion of the operated segment, CDA surgery was first reported in 1990, and a certain range of motion was preserved by inserting an artificial intervertebral disc while decompressing, but the high ossification rate of CDA is also one of its unique disadvantages, and the incidence of heterotopic ossification in two segments undergoing CDA can be as high as 15.9% at 7 years of follow-up (Gornet et al., 2019). MI-PCF has advantages compared with anterior approaches (ACDF and CDA), such as eliminating the need for internal fixation devices, reducing adjacent segment degeneration, and avoiding pseudoarthrosis formation and heterotopic ossification formation. ...
Introduction
This study is a systematic review and meta-analysis that investigates the efficacy of different surgical methods for treating cervical disc herniation or cervical foraminal stenosis.
Research question
The research aimed to compare the efficacy of Minimally Invasive Posterior Cervical Foraminotomy (MI-PCF) with anterior approaches, namely Anterior Cervical Discectomy and Fusion (ACDF) and Cervical Disc Arthroplasty (CDA).
Material and methods
The study included a comprehensive review of eight articles that compared ACDF and MI-PCF, and four articles that compared CDA to MI-PCF.
Results
The results indicated no significant difference in surgical duration, hospital stay, complication rates, and reoperation rates between MI-PCF and ACDF. However, when comparing CDA with MI-PCF, it was found that CDA had a higher complication rate, while MI-PCF had a higher reoperation rate.
Discussion and conclusion
Despite these findings, the study recommends MI-PCF as the preferred surgical method for cervical radiculopathy, owing to the advancements in minimally invasive techniques. However, these findings are preliminary, and further research with longer follow-up periods and larger sample sizes is necessary to confirm these findings and to further explore the potential advantages and disadvantages of these surgical methods.
... ACDF provides high recovery rate, pain reduction and improvement in neurological status. In the literature there is substantial data from randomized control trials on cervical disc arthroplasty with patients undergoing 1 and 2 level ACDFs which evaluated neck-related physical function and quality of life outcomes [3,4,5]. The results of procedure are overall good but the biomechanical effects on the discs and vertebra after the procedure remain largely unclear. ...
Cervical discopathy is commonly associated with pain in the cervical spine which may affect patients’ quality of life. If conservative treatment fails to relieve the pain for at least 6 months and/or if neurological deficit progresses, the surgical treatment is taken under consideration. The aim of this study was to evaluate health-related quality of life (HRQOL) and disability of patients after single- and multi-level anterior cervical discectomy and fusion (ACDF) with standalone polyetheretherketone (PEEK) cages. The study evaluated how ACDF influenced particular aspects of patients’ quality of life in the context of radiological outcome. The study included 30 consecutive patients with single- or multi-level cervical disc herniation. Patients underwent clinical and radiological evaluation before and one year after the ACDF procedure. For each patient, we assessed the severity of cervical pain with a numerical rating scale (NRS) and filled the neck disability index questionnaire (NDI). The health-related quality of life was assessed with the Polish version of 36-Item Short Form Survey (SF-36). A significant decrease in all NDI aspects indicates a significant improvement after surgery. The quality of life in all aspects assessed with SF-36 scale was also improved. A moderate decrease in cervical spine mobility coexisted with a good outcome of the neurosurgical procedure. In the opinion of patients, the most important aspect after the cervical spine surgery is the reduction of pain severity. ACDF surgery is an effective method to reduce the severity of pain in patients with degenerative disc disease. ACDF improves the quality of patient’s life. According to the study results the physical role improved most significantly; the least improvement was noted in role-emotional aspect. Up to 83% of patients achieved a reduction of the NDI index by 5 or more points after surgical treatment which proves the high effectiveness of the surgical treatment. No statistically significant difference was noted between patients with single and multi – level discopathy. Up to 97% of patients who underwent ACDF reported a significant decrease in pain severity measured with NRS.
... However, the complications of ACDF, such as pseudarthrosis, C5 palsy, and hematoma, are troublesome for spinal surgeons [10][11][12][13][14]. A growing number of studies have reported comparable clinical improvement and a low rate of complications in single-and two-level ACDF [15,16]. Nevertheless, a few articles studied 3-level or even 4-level ACDF due to the relatively lower rate of multilevel cervical spondylotic myelopathy [17][18][19][20][21][22][23][24]. ...
Objective
Our objective is to estimate the clinical effectiveness of 3-level and 4-level anterior cervical discectomy and fusion (ACDF) in the management of cervical spondylotic myelopathy (CSM).
Methods
We conducted a thorough search in English databases. We gathered the data on surgical variables and complications to contrast the clinical effectiveness between 3-level and 4-level. We utilized RevMan 5.3 and STATA 12.0 to analyze the data.
Results
Finally, eight studies met inclusion criteria of this study. Our findings indicated that operation time [p for heterogeneity = 0.23, I² = 32 %, p＜0.00001, OR = −24.93, 95%CI (−32.39,-17.49)], blood loss [p for heterogeneity = 0.33, I² = 10 %, p＜0.00001, OR = −60.87, 95%CI (−85.43,-36.32)] and the total number of complications [p for heterogeneity = 0.36, I² = 0 %, p = 0.004, OR = 0.37, 95%CI (0.18,0.72)] in 3-level ACDF were significantly less than in 4-level ACDF. No marked difference was found in hospital stay, revision rate, fusion rate, the number of readmissions, infection, hematoma, or pseudarthrosis between 3-level and 4-level ACDF.
Conclusions
It is easy to understand that performing 4-level needs more operation time and blood loss. No obvious discrepancy was found with regard to the subgroups of complications between the two procedures, yet 4-level procedures had a more number of complications.
... The improvement of arm pain after 12 months was 5.5 points (from 6.4 to 0.9) and for neck pain 4.5 points (from 5.8 to 1.3) in our study. This also corresponds well with the scientific literature published hitherto [16,[42][43][44]. ...
Objectives:
To assess the clinical and radiological outcomes after ACDF with 3D printed cellular titanium cages filled with bone marrow and to compare the clinical and radiological results with the current scientific literature.
Methods:
ACDF was performed monosegmentally under standardized conditions. X-rays were analyzed to determine the range of motion, fusion rates, and subsidence preoperatively and 3 and 12 months postoperatively. Clinical outcome measurements included neck disability index (NDI), visual analogue scale (VAS) for brachialgia and cervicalgia, and patient satisfaction.
Results:
18 patients were included in the study. The mean RoM decreased from 7.7° ± 2.6 preoperatively to 1.7° ± 1.1° after 3 months and 1.8° ± 1.2° 12 months after surgery. The fusion rates were at 94.4% after 3 and 12 months. The mean subsidence was 0.9 mm ± 0.5 mm 3 months postoperatively and 1.1 mm ± 0.5 mm 12 months after surgery. The mean NDI improved significantly from preoperatively to 12 months postoperatively (34.6 ± 6.2 and 3.4 ± 4.1, respectively). The VAS-neck also showed a large improvement from 5.8 ± 2.2 before and 1.3 ± 1.4 12 months after surgery, as did the VAS-arm (6.4 ± 1.5 and 0.9 ± 1.6, respectively). Patient satisfaction was high throughout the follow-up period.
Conclusion:
ACDF with a 3D printed titanium cage resulted in fast fusion without pathological subsidence. In comparison to other cage materials such as PEEK, the 3D printed titanium cage was noninferior in regard to its fusion rate and clinical results.
... [6][7][8][9] The potential to alleviate adjacent segment degeneration (ASD) with CDA has also been suggested but still needs long-term data for corroboration. 6,[10][11][12][13] However, the emerging popularity of CDA has raised the concern of heterotopic ossification (HO), with variable incidence rates ranging from 2.9% to more than half of the patients over time among many series. [14][15][16][17][18] Radiographically highgrade HO after CDA could certainly limit segmental mobility at the indexed level, but it rarely alters neurological improvement or clinical outcomes. ...
BACKGROUND
Heterotopic ossification (HO) is a well-documented complication of cervical disc arthroplasty (CDA), although it rarely causes adverse clinical effects. Despite high-grade HO possibly limiting segmental mobility, it is reportedly seldom associated with symptoms.
OBSERVATIONS
The authors report a case of a 46-year-old male patient who underwent hybrid CDA and anterior cervical discectomy and fusion for 3-level cervical disc herniation that caused myeloradiculopathy. The surgery was successful; the patient experienced nearly complete recovery postoperatively. The follow-up images, including computed tomography and magnetic resonance imaging scans, showed satisfactory decompression at the indexed levels without residual osteophytes or ossification of the posterior longitudinal ligament. However, 10 years later, the patient presented with symptomatic compressive myelopathy caused by severe HO that prompted a secondary surgery.
LESSONS
Although it is generally reported in the literature that HO is clinically innocuous, in this patient, it gradually and progressively developed and caused myelopathy, requiring a secondary surgery. Symptomatic HO can be expected over time, and patients with a high risk of HO deserve long-term follow-up after CDA. Further investigations are warranted to corroborate these risk factors, including multilevel calcified disc herniation, severe spondylosis, and suboptimal placement of the device during primary CDA surgery.
BACKGROUND AND PURPOSE
Cervical total disc replacement (CTDR) was developed to decompress nervous structures, preserve spinal biomechanics, and reduce postoperative complications such as nonunion or fracture. There is no published literature regarding the optimal content, timing and duration of postoperative physical therapy (PT) for CTDR. Therefore, the purpose of this case report is to describe the postoperative PT management and one-year outcomes of a subject with CTDR as it relates to pain, function and quality of life.
CASE DESCRIPTION
A 37-year-old male and Brazilian Jiu Jitsu athlete with cervical radiculopathy underwent a C5-C6 and C6-C7 discectomy with CTDR. The subject attended PT for 14 sessions across 16 weeks. Interventions included manual therapy (soft tissue and joint mobilization), therapeutic exercise targeting cervical spine, thoracic spine and upper extremity mobility and strength, and weightlifting body mechanics education. Radiographic confirmation of prosthesis placement and healing was monitored at postoperative weeks six and 12. The PT program was designed and progressed according to tissue healing timelines, subject response, clinical reasoning, and sport-specific demands.
OUTCOMES
Improvements were noted with Neck Disability Index (14% to 0%), Patient Specific Functional Scale (3.4/10 to 10/10), Short Form-12 Physical Score (+5.4) and Mental Score (+25.7), and Numeric Pain Rating Scale (2/10 to 0/10). Cervical active range of motion (in degrees) improved in all motions, and deep neck flexor endurance from 5-35 seconds.
DISCUSSION
A multimodal PT program following CTDR based on tissue healing timelines and clinical reasoning improved pain, function and quality of life up to one year postoperatively without adverse effects in this athlete.
LEVEL OF EVIDENCE
4
Study Design
A retrospective cohort utilizing the PearlDiver Patient Claims Database.
Objective
Cervical disc arthroplasty (CDA) is accepted treatment for cervical radiculopathy; however, it may also be safe and effective in myelopathy. Thus, we compared clinical characteristics and outcomes in patients undergoing CDA and anterior cervical discectomy and fusion (ACDF) for degenerative cervical myelopathy (DCM) specifically.
Methods
Patients undergoing CDA or ACDF between 2015-2019 were identified with follow-up through 2021. Univariate and multivariable analyses were performed to identify factors associated with either procedure. Reoperation rates were compared using propensity-matched analysis.
Results
We identified n = 2391 CDA and n = 50 845 ACDF procedures for DCM. Factors favoring CDA included: female sex, younger age, lower CCI, lower incidence of obesity, osteoporosis, diabetes, or smoking ( P ≤ .001); remaining significant after multivariable logistic regression except for sex ( P = .06). Single-level surgery was more predictive for undergoing CDA. CDA patients had lower 90-day readmissions, complications, and lower opioid utilization. The overall reoperation rate was 5%. Predictors of reoperation included: male sex, younger age, greater CCI, obesity, osteoporosis, diabetes, smoking, and multi-level surgery; all remaining significant after multivariable analysis except for diabetes ( P = .23) and CCI ( P = .05). After propensity-matching CDA and ACDF patients (n = 2391), there was no difference in re-operation rates ( P = .47).
Conclusions
CDA patients were healthier (less obesity, smoking, diabetes, better CCI) and represented 4.5% of anterior procedures for DCM. In univariate analysis, readmission rates, medical complications, and opioid use were lower in CDA patients, despite a similar reoperation rate. Considering these findings, CDA might be used very selectively for DCM.
Background
Cervical disc arthroplasty is a well-established alternative to anterior cervical fusion but requires precise placement for optimal outcomes. We present the case of a 2-level cervical disc arthroplasty with suboptimal implantation of the interbody devices, requiring revision corpectomy. Supplemental video, Supplemental Digital Content 1 (http://links.lww.com/CLINSPINE/A358) content of the revision surgery is also provided. This report highlights the importance of proper implant sizing and position and reviews the nuances of surgical revision.
Methods
A retrospective review of the clinical and radiographic data was performed from prior to the index operation through the 3-month postoperative period after the surgical revision.
Results
The patient presented approximately 2 years post-cervical arthroplasty with increasing neck pain and early cervical myelopathy. An imaging workup revealed severe cervical stenosis at the caudal level with cord compression and concern for device failure. Intraoperatively, the core of the caudal device was found to have ejected into the spinal canal. A cervical corpectomy of the intervening vertebra with the removal of both devices was performed. The patient had a complete neurologic recovery.
Conclusion
Although failure of a cervical disc arthroplasty device is rare, the likelihood can be significantly increased with poor sizing (over or under sizing), asymmetric placement, endplate violation, or poor patient selection. In the case presented herein, early device failure was unrecognized, and the patient went on to develop progressive cervical myelopathy requiring revision corpectomy.
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.
Purpose
No clear consensus exists on which anterior surgical technique is most cost-effective for treating cervical degenerative disk disease (CDDD). One of the most common treatment options is anterior cervical discectomy with fusion (ACDF). Anterior cervical discectomy with arthroplasty (ACDA) was developed in an effort to reduce the incidence of clinical adjacent segment pathology and associated additional surgeries by preserving motion. This systematic review aims to evaluate the evidence regarding the cost-effectiveness of anterior surgical decompression techniques used to treat radiculopathy and/or myelopathy caused by CDDD.
Methods
The search was conducted in PubMed, EMBASE, Web of Science, CINAHL, EconLit, NHS-EED and the Cochrane Library. Studies were included if healthcare costs and utility or effectivity measurements were mentioned.
Results
A total of 23 studies were included out of the 1327 identified studies. In 9 of the 13 studies directly comparing ACDA and ACDF, ACDA was the most cost-effective technique, with an incremental cost effectiveness ratio ranging from 98.475/QALY. There was great heterogeneity between the costs of due to different in- and exclusion criteria of costs and charges, cost perspective, baseline characteristics, and calculation methods. The methodological quality of the included studies was moderate.
Conclusion
The majority of studies report ACDA to be a more cost-effective technique in comparison with ACDF. The lack of uniform literature impedes any solid conclusions to be drawn. There is a need for high-quality cost-effectiveness research and uniformity in the conduct, design and reporting of economic evaluations concerning the treatment of CDDD.
Trial registration
PROSPERO Registration: CRD42020207553 (04.10.2020).
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 remain 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 six months until four 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 ageing of the population and the rising healthcare costs, there is an urgent need for a solid clinical cost-effectiveness trial addressing this question.
Objective
The objective of this study was to compare outcomes and patient satisfaction, and secondly to compare complication rates between one- and two-level anterior cervical discectomy and fusion (ACDF) for cervical radiculopathy.
Methods
Data from patients receiving one- or two-level ACDF for cervical radiculopathy at two institutions were prospectively collected and retrospectively analysed. Patients were separated into one-level ACDF and two-level ACDF. Comparison analyses of patient-reported outcome measures (PROMs) comprising Visual Analogue Scale for neck pain (VAS-NP) and arm pain (VAS-AP), Neck Disability Index (NDI), and EQ-5D 3-level version (EQ-5D-3L) were performed between baseline and 1-year follow-up and between groups as well as achievement of minimal clinically important differences (MCID) in PROMs and satisfaction. Additionally, complications were compared between groups.
Results
A total of 410 patients (270 one-level and 140 two-level) were included. PROMs improved significantly from baseline to 1-year follow-up (p < 0.001) in both groups. When comparing PROMs between one- and two-level ACDF, a trend towards greater improvement was observed in patients undergoing one-level ACDF, notably in EQ-5D-3L (p = 0.073). Significantly more patients in the one-level group achieved MCID in VAS-NP compared to patients in the two-level group (56% vs 44%, p = 0.025). Two hundred and ninety-six (67%) patients reported to be satisfied, but the one-level group trended to be more satisfied (70% vs. 62%). One-level ACDF further demonstrated a trend of more favourable complication profiles; however, complication rates were low in both groups. The risk of intraoperative complications was 2.4%, postoperative complications in-hospital were 1.2%, and patient-reported postoperative events post-discharge 42%.
Conclusions
One- and two-level ACDF are effective procedures for degenerative cervical nerve root compression. Yet, significantly more patients in the one-level group achieved MCID in neck pain compared to patients in the two-level group.
Background Context
Anterior cervical discectomy and fusion (ACDF) is a common surgical procedure. There is markedly less data on outcomes after three- and four-level cases than one- and two-level cases.
Purpose
To compare perioperative 90-day adverse events and five-year reoperation rates between isolated one-, two-, three-, and four-level ACDF cases.
Study Design/Setting
Retrospective review of a large national database
Patient Sample
Overall, 97,081 patients undergoing ACDF were identified, of which one-level cases were 42,382 (43.7%), two-level cases were 24,055 (24.8%), three-level cases were 28,293 (29.1%), and four-level cases were 2,361 (2.4%).
Outcome Measures
Ninety-day adverse events and five-year reoperation rates.
Methods
The 2010 to Q1 2020 PearlDiver database was queried to identify patients who underwent elective ACDF for degenerative pathology without corpectomy or concomitant posterior procedures. Univariate and multivariate analyses were performed to compare outcomes of sub-cohorts with varying number of levels addressed by ACDF.
Results
Of the 97,081 cases identified, patient characteristics and complication rates differed between the cohorts defined by levels treated. Univariate analyses revealed statistically different rates of 90-day any, serious, and minor adverse event rates between the groups, but the differences were all less than 2.5%. Readmission rates were statistically different by 2.9%, dysphagia by 3.2%, and prolonged length of stay (LOS) by 6.3%.By multivariate analyses, three-level ACDF cases were not found to have greater 90-day adverse outcomes than two-level cases. Four-level ACDF cases were found to have significantly greater odds ratios (OR) of readmission, dysphagia, and prolonged LOS (relative to one-level cases, OR 1.28, 1.63, and 1.97, respectively) but not other 90-day adverse events.Reoperation rates at five years for one-, two-, three-, and four-level cases were 13.0%, 13.5%, 15.0%, and 22.1%, respectively (log-rank p < 0.001).
Conclusion
The current study represents one of the largest comparative studies of patients undergoing one-, two-, three-, and four-level ACDF. While odds of 90-day adverse events were not greater for three- vs two-level cases, four-level cases had several that were higher odds than one-level cases. Reoperation and dysphagia rates were higher for four-level cases than lesser levels. While these outcomes were found to be acceptable, they should help guide hospital planning and patient counselling.
Background
Operating room (OR) utilization is the ratio of total hours of elective cases divided by the number of hours the OR is staffed. Suboptimal OR utilization wastes medical resources, increases overall cost to healthcare organizations and ultimately insurance carriers. Accurate OR case length estimates are an essential component of optimizing OR utilization. The objective of the study is to evaluate the accuracy of spine surgeons, anesthesiologists, and OR nurse managers as compared to a computerized scheduling system when estimating the time needed to perform three common spine procedures. A secondary goal is to evaluate if there is a difference in how providers interpret “OR time needed” when making their estimations. We hypothesize that surgeons are less accurate than OR nurse managers and anesthesiologists when estimating OR time.
Methods
Spine surgeons, anesthesiologists, and OR nurse managers at a single, tertiary academic institution were provided a survey to estimate the OR time needed to perform three common spine procedures. OR nurse managers and anesthesiologists were further asked to provide estimates based on the surgeon performing the procedure. Their predictions were then compared to the actual recorded times (averaged for the last 20 consecutive cases of each procedure done by each surgeon) and to the time predicted by the computerized scheduling system at our institution. The estimations provided by the surgeons were compared against their own recorded times. Patient and surgery data were collected to perform a secondary analysis to determine factors that may have significantly affected the prediction. Predictions within 30 minutes of the actual recorded time were defined as accurate.
Results
Fourteen providers completed the survey. The group was composed of 5 orthopaedic surgeons, 3 neurosurgeons, 3 anesthesiologists, and 3 OR nurse managers. The estimates provided by anesthesiologists and surgeons were closer to the surgical control time (SCT) while the estimate provided by OR nurse managers was closer to the total OR time (TORT) for the three procedures evaluated. Although the computer system estimations were closer to both, mean SCT and mean TORT, it was not able to accurately schedule most cases (<50% of cases were scheduled within 30 minutes of the actual recorded times
Conclusions
Surgeon's and Anesthesiologists estimates were closer to the SCT while the estimate of the OR nurse managers was closer to TORT. Although the computer scheduling system's average scheduling time was close to the actual OR time, its ability to accurately individual cases could be improved.
Study design:
Retrospective Cohort Study OBJECTIVE: To compare long-term clinical and radiographic outcomes following 3- and 4-level anterior cervical discectomy and fusion (ACDF).
Methods:
Patients who underwent primary 3- or 4- level ACDF were retrospectively identified. Demographic data and patient-reported outcome measures (PROMs) were collected through chart review. PROM surveys were administered preoperatively as baseline measurements and at one-year postoperatively. Outcomes included the Neck Disability Index (NDI), Short-Form 12 Physical (PCS-12) and Mental (MCS-12) Components, and Visual Analog Scale (VAS) Neck and Arm pain scores. Cervical sagittal alignment parameters included C2-C7 Lordosis, Segmental Lordosis, Sagittal Vertical Axis, and T1 Slope. Multivariate regression models were used to compare changes in PROMs and radiographic measurements over time between 3- and 4-level ACDF. Correlation coefficients were calculated to compare delta scores of PROMs and radiographic measurements.
Results:
VAS Neck and Arm scores significantly improved from baseline in both cohorts. Only the 3-level group showed significant improvements perioperatively for NDI and PCS-12. No significant differences were found in improvement of clinical outcomes between groups. Pooled results demonstrated a significant negative correlation between perioperative change in segmental lordosis and VAS Arm scores. A significant negative correlation was also seen between perioperative change in SVA and MCS-12 and VAS Neck scores. C2-C7 lordosis significantly increased postoperatively in only the 3-level ACDF group.
Conclusions:
Patients undergoing both 3- and 4-level ACDF experienced significant clinical improvements without significant differences between groups. Radiographic measures of segmental lordosis and SVA were also found to correlate with changes in clinical outcomes.
Study design:
Retrospective.
Objective:
The purpose of this study is to evaluate depressive symptoms as measured by the PHQ-9 survey and correlated them with scores from the SF-12 and VR-12 Mental Component Summary (MCS).
Summary of background data:
With the rising incidence of depression and the need to identify modifiable risk factors before surgery, it is increasingly important to screen for preoperative depressive symptoms in spine surgery. While the Patient Health Questionnaire-9 (PHQ-9) has favorable characteristics as a depressive symptom screening instrument, it has not been evaluated within cervical spine surgery.
Methods:
A prospectively maintained surgical registry was reviewed for patients undergoing single or multilevel anterior cervical discectomy and fusion (ACDF) or cervical disc replacement (CDR) from March 2016 until May 2019. Included patients underwent a procedure for degenerative spinal pathology. We collected demographic, baseline, and perioperative variables. The mean scores for postoperative PHQ-9, Short Form-12 (SF-12), and Veterans RAND-12 (VR-12) surveys were calculated, and an average change between preoperative and postoperative scores. Scatterplots depicted the association of SF-12 MCS and VR-12 MCS with PHQ-9. We evaluated the relationship of PHQ-9 with SF-12 MCS and VR-12 MCS scores by calculating a Pearson's correlation coefficient and time-independent partial correlation coefficient.
Results:
152 patients underwent single or multilevel level cervical spine surgery (ACDF: 73% and CDR: 27%). The average age was 42.4 and 39% were female. Compared to preoperative scores, significant increases were observed among postoperative PHQ-9, SF-12, and VR-12 MCS surveys (p≤0.001). We observed strong correlations between SF-12 and VR-12 MCS with PHQ-9 scores for both assessed correlations.
Conclusion:
Patients undergoing ACDF or CDR demonstrated significant improvement with PHQ-9, SF-12 MCS and VR-12 MCS instruments. PHQ-9 scores strongly correlated with SF-12 MCS and VR-12 MCS. Our findings indicate PHQ-9 is a valid tool to evaluate pre and postsurgical depressive symptoms.
Level of evidence:
4.
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.
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.
Anterior cervical discectomy and fusion (ACDF) is the gold standard for treating symptomatic cervical disc degeneration. Cervical total disc replacements (TDRs) have emerged as an alternative for some patients. The purpose of this study was to evaluate the safety and effectiveness of a new TDR device compared with ACDF for treating single-level cervical disc degeneration.
This was a prospective, randomized, controlled, multicenter Food and Drug Administration (FDA) regulated Investigational Device Exemption (IDE) study. A total of 245 patients were treated (164 TDR: 81 ACDF). The primary outcome measure was overall success based on improvement in Neck Disability Index (NDI), no subsequent surgical interventions, and no adverse events (AEs) classified as major complications. Secondary outcome measures included SF-12, visual analog scale (VAS) assessing neck and arm pain, patient satisfaction, radiographic range of motion, and adjacent level degeneration. Patients were evaluated preoperatively and postoperatively at 6 weeks, 3, 6, 12, 18, and 24 months. The hypothesis was that the TDR success rate was non-inferior to ACDF at 24 months.
Overall success rates were 73.6% for TDR and 65.3% for ACDF, confirming non-inferiority (p < 0.0025). TDR demonstrated earlier improvements with significant differences in NDI scores at 6 weeks and 3 months, and VAS neck pain and SF-12 PCS scores at 6 weeks (p<0.05). Operative level range of motion in the TDR group was maintained throughout follow-up. Radiographic evidence of inferior adjacent segment degeneration was significantly greater with ACDF at 12 and 24 months (p < 0.05). AE rates were similar.
Mobi-C TDR is a safe and effective treatment for single-level disc degeneration, producing outcomes similar to ACDF with less adjacent segment degeneration.
Level I.
This study adds to the literature supporting cervical TDR as a viable option to ACDF in appropriately selected patients with disc degeneration.
Object:
The purpose of this study was to evaluate the safety and effectiveness of 2-level total disc replacement (TDR) using a Mobi-C cervical artificial disc at 48 months' follow-up.
Methods:
A prospective randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc was conducted at 24 centers in the U.S. Three hundred thirty patients with degenerative disc disease were randomized and treated with cervical total disc replacement (225 patients) or the control treatment, anterior cervical discectomy and fusion (ACDF) (105 patients). Patients were followed up at regular intervals for 4 years after surgery.
Results:
At 48 months, both groups demonstrated improvement in clinical outcome measures and a comparable safety profile. Data were available for 202 TDR patients and 89 ACDF patients in calculation of the primary endpoint. TDR patients had statistically significantly greater improvement than ACDF patients for the following outcome measures compared with baseline: Neck Disability Index scores, 12-Item Short Form Health Survey Physical Component Summary scores, patient satisfaction, and overall success. ACDF patients experienced higher subsequent surgery rates and displayed a higher rate of adjacent-segment degeneration as seen on radiographs. Overall, TDR patients maintained segmental range of motion through 48 months with no device failure.
Conclusions:
Four-year results from this study continue to support TDR as a safe, effective, and statistically superior alternative to ACDF for the treatment of degenerative disc disease at 2 contiguous cervical levels. Clinical trial registration no.: NCT00389597 ( clinicaltrials.gov ).
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).
The object of this study is to compare radiographic outcomes of anterior cervical decompression and fusion (ACDF) versus cervical disc replacement using the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN) in terms of range of motion (ROM), Functional spinal unit (FSU), overall sagittal alignment (C2–C7), anterior intervertebral height (AIH), posterior intervertebral height (PIH) and radiographic changes at the implanted and adjacent levels. The study consisted of 105 patients. A total of 63 Bryan disc were placed in 51 patients. A single level procedure was performed in 39 patients and a two-level procedure in the other 12. Fifty-four patients underwent ACDF, 26 single level cases and 28 double level cases. The Bryan group had a mean follow-up 19 months (12–38). Mean follow-up for the ACDF group was 20 months (12–40 months). All patients were evaluated using static and dynamic cervical spine radiographs as well as MR imaging. All patients underwent anterior cervical discectomy followed by autogenous bone graft with plate (or implantation of a cage) or the Bryan artificial disc prosthesis. Clinical evaluation included the visual analogue scale (VAS), and neck disability index (NDI). Radiographic evaluation included static and dynamic flexion-extension radiographs using the computer software (Infinitt PiviewSTAR 5051) program. ROM, disc space angle, intervertebral height were measured at the operative site and adjacent levels. FSU and overall sagittal alignment (C2–C7) were also measured pre-operatively, postoperatively and at final follow-up. Radiological change was analyzed using χ
2 test (95% confidence interval). Other data were analyzed using the mixed model (SAS enterprises guide 4.1 versions). There was clinical improvement within each group in terms of VAS and NDI scores from pre-op to final follow-up but not significantly between the two groups for both single (VAS p = 0.8371, NDI p = 0.2872) and double (VAS p = 0.2938, NDI p = 0.6753) level surgeries. Overall, ROM and intervertebral height was relatively well maintained during the follow-up in the Bryan group compared to ACDF. Regardless of the number of levels operated on, significant differences were noted for overall ROM of the cervical spine (p < 0.0001) and all other levels except at the upper adjacent level for single level surgeries (p = 0.2872). Statistically significant (p < 0.0001 and p = 0.0172) differences in the trend of intervertebral height measurements between the two groups were noted at all levels except for the AIH of single level surgeries at the upper (p = 0.1264) and lower (p = 0.7598) adjacent levels as well as PIH for double level surgeries at the upper (p = 0.8363) adjacent level. Radiological change was 3.5 times more observed for the ACDF group. Clinical status of both groups, regardless of the number of levels, showed improvement. Although clinical outcomes between the two groups were not significantly different at final follow-up, radiographic parameters, namely ROM and intervertebral heights at the operated site, some adjacent levels as well as FSU and overall sagittal alignment of the cervical spine were relatively well maintained in Bryan group compared to ACDF group. We surmise that to a certain degree, the maintenance of these parameters could contribute to reduce development of adjacent level change. Noteworthy is that radiographic change was 3.5 times more observed for ACDF surgeries. A longer period of evaluation is needed, to see if all these radiographic changes will translate to symptomatic adjacent level disease.
In cervical multi-level degenerative pathology, considering the morbidity of the extensive fusion techniques, some authors advocate for the multilevel disc replacement. This study compared the safety and efficacy of disc replacement with an unconstrained prosthesis in multi- versus single-level patients. A total of 231 patients with cervical degenerative disc disease (DDD) who were treated with cervical disc replacement and completed their 24 months follow-up were analyzed prospectively: 175 were treated at one level, 56 at 2 levels or more. Comparison between both groups was based on usual clinical and radiological outcomes [Neck Disability Index (NDI), Visual Analog Scale (VAS), Range of Motion, satisfaction]. Safety assessments, including complication and subsequent surgeries, were also documented and compared. Mean NDI and VAS scores for neck and arm pain were improved in both groups similarly. Improvement of mobility at treated segments was also similar. Nevertheless, in the multi-level group, analgesic use was significantly higher and occurrence of Heterotopic Ossification significantly lower than in the single-level group. Subject satisfaction was nearly equal, as 94.2% of single-level group patients would undergo the surgery again versus 94.5% in the multi-level group. The overall success rate did not differ significantly. Multi-level DDD is a challenging indication in the cervical spine. This study showed no major significant clinical difference between the two groups. We need further studies to know more about the impact of multi-level arthroplasty, especially on the adjacent segments, but these results demonstrate initial safety and effectiveness in this patient sample.
Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of Bryan(R) cervical disc prosthesis.
The authors retrospectively reviewed radiographic and clinical outcomes in 52 patients who received the Bryan(R) Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of functional spine unit (FSU), and the C2-7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria, visual analogue pain scale (VAS) and neck disability index (NDI).
A total of 71 Bryan(R) disc were placed in 52 patients. A single-level procedure was performed in 36 patients, a two-level procedure in 13 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria, and showed significant improvement by VAS and NDI score (p < 0.05). The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level (p < 0.05). 97% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 88.5% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 70% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 66.6% of the patients postoperatively.
Arthroplasty using the Bryan(R) disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although the early results are promising, this is a relatively new approach, therefore long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.
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)
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 )
OBJECTIVE
Cervical disc arthroplasty (CDA) has been demonstrated to be an effective treatment modality for single-level cervical radiculopathy or myelopathy. Its advantages over an anterior cervical discectomy and fusion (ACDF) include motion preservation and decreased reoperations at the index and adjacent segments up to 7 years postoperatively. Considering the fact that many patients have multilevel cervical disc degeneration (CDD), the authors performed a systematic review of the clinical studies evaluating patients who underwent multilevel CDA (2 or more levels).
METHODS
A systematic review in the MEDLINE database was performed. Clinical studies including patients who had multilevel CDA were selected and included. Case reports and literature reviews were excluded. Articles were then grouped according to their main study objective: 1) studies comparing multilevel CDA versus ACDF; 2) studies comparing single-level CDA versus multilevel CDA; and 3) multilevel CDA after a previous cervical spine surgery.
RESULTS
Fourteen articles met all inclusion criteria. The general conclusions were that multilevel CDA was at least as safe and effective as ACDF, with preservation of cervical motion when compared with ACDF and potentially with fewer reoperations expected in most of the studies. Multilevel CDAs are clinically effective as single-level surgeries, with good clinical and radiological outcomes. Some studies reported a higher incidence of heterotopic ossification in multilevel CDA when compared with single-level procedures, but without clinical relevance during the follow-up period. A CDA may be indicated even after a previous cervical surgery in selected cases.
CONCLUSIONS
The current literature supports the use of multilevel CDA. Caution is necessary regarding the more restrictive indications for CDA when compared with ACDF. Further prospective, controlled, multicenter, and randomized studies not sponsored by the device manufactures are desirable to prove the superiority of CDA surgery over ACDF as the treatment of choice for CDD in selected cases.
Background:
Cervical disc arthroplasty (CDA) has emerged as an alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of cervical pathologies. Studies are on-going to assess the long term outcomes of CDA. This study assessed the safety and efficacy of the Prestige(®) LP Disc at 84-months follow up.
Methods:
Prospective data from 280 CDA patients with single-level cervical disc disease with radiculopathy or myelopathy were compared with 265 historical control ACDF patients. Clinical and radiographic follow up was completed pre-operatively, intraoperatively, and at intervals up to 84 months.
Results:
Follow-up rate was 75.9% for CDA and 70.0% for ACDF patients. Statistical improvements (p < 0.001) in Neck Disability Index (NDI), neck/arm pain, and SF-36 were achieved by 1.5 months in both groups and maintained through 84 months. At 84 months, 86.1% of CDA versus 80.1% of ACDF patients achieved NDI success, (≥15-point improvement over baseline). Mean NDI score improvements exceeded 30 points in both groups. SF-36 PCS/MCS mean improvements were 13.1±11.9/8.2±12.3 points for CDA and 10.7±11.8/8.3±13.6 points for ACDF. Neurological success was 92.8% for CDA and 79.7% for ACDF patients. The rate of Overall Success was 74.9% for CDA and 63.2% for ACDF. At 84 months, 17.5% of CDA and 16.6% of ACDF patients had a possibly implant- or implant-surgical procedure-related adverse event. Eighteen (6.4%) CDA and 29 (10.9%) ACDF patients had a second surgery at the index level. In CDA patients, mean angular motion at the target level was maintained at 24 (7.5°) and 84 (6.9°) months. Bridging bone was reported in 5.9%/9.5%/10.2%/13.0% of CDA patients at 24/36/60/84 months. Change in mean preoperative angulation of the adjacent segment above/below the index level was1.06±4.39/1.25±4.06 for CDA and (-0.23)±5.37/1.25±5.07 for ACDF patients. At 84 months, 90.9% of CDA and 85.6% of ACDF patients were satisfied with the results of their treatment.
Conclusions:
Prestige LP maintained significantly improved clinical outcomes and segmental motion; statistical superiority of CDA was concluded for overall success. This investigational device exemption study was sponsored by Medtronic Spinal and Biologics, Memphis, TN. Study approved by the Hughston Sports Medicine Center Institutional Review Board on January 7, 2005. Clinical trial registered at clinicaltrials.gov: NCT00667459. All participants signed an informed consent.
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 )
Study design:
A retrospective study OBJECTIVE.: To analyze the influence of the number of cervical fusion levels on total cervical motion and Health related quality of life (HRQoL) in patients with solid anterior cervical fusions (ACF).
Summary of bakground data:
Few studies have analyzed the degree to which cervical range of motion (ROM) and HRQoLs are affected by the number of cervical fusion segments.
Methods:
We analyzed a cohort of patients who underwent ACF for degenerative disc disease. To assess the clinical outcomes and HRQoL, pre-operative, 1 and 2-year post-operative neck and arm pain, visual analogue scale (VAS), neck disability index (NDI), and short form-36 (SF-36) were analyzed. Radiographically, C2-7 and C0-2 ROM, C2-7 sagittal vertical axis (SVA), and Kellgren grade of radiographic adjacent segment pathology (RASP) were evaluated.
Results:
A total of 105 patients (M:F = 46:59, mean age of 51.4 years) were enrolled. There were 36 patients who underwent single-level ACF (group 1), 41 patients who had a double level ACF (group 2), and 28 patients who underwent ACF involving three or more levels (group 3). There was no decrease of C2-7 motion in group 1, a mean 7° decrease in group 2, a mean 18° decrease in those who underwent a three level ACF and a mean 22° decrease after four levels ACF. The grade of RASP was not influenced by the number of fusion levels. All HRQoL parameters showed no significant correlation between number of fusion levels, cervical ROM, and SVA.
Conclusions:
Single level ACF showed no decrease in total cervical motion; multilevel ACF decreased cervical motion by a mean of 7.8° per segment of fusion. Progression of RASP showed no correlation with the number of fusion levels. HRQoLs were not influenced by the number of fusion levels, cervical ROM or SVA after solid ACF.
Level of evidence:
3.
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.
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.
Although arthroplasty is an accepted option for two-level disease, there is a paucity of data regarding outcomes of two-level cervical arthroplasty. The current study was designed to determine differences between two-level cervical arthroplasty and anterior fusion.
Seventy-seven consecutive patients who underwent two-level anterior cervical operations for degenerative disc disease were divided into the arthroplasty (37 patients) and fusion (40 patients) groups. Clinical outcomes were measured by Visual Analogue Scale (VAS) of neck and arm pain, Japanese Orthopedic Association (JOA) scores, and Neck Disability Index (NDI). Every patient was evaluated by radiography and computed tomography for fusion or detection of heterotopic ossification.
Thirty-seven patients (with 74 levels of Bryan discs) were compared with 40 patients who had two-level anterior fusion (mean follow-up of 39.6 ± 6.7 months). There was no difference in sex, but the mean age of the arthroplasty group was significantly younger (52.1 ± 9.1 vs. 63.0 ± 10.6 years, p < 0.001). The mean estimated blood loss was similar (p = 0.135), but the mean operation time was longer in the arthroplasty group (315.5 ± 82.0 versus 224.9 ± 61.8 min, p < 0.001). At 24 months post-operation, the arthroplasty group had increased their range of motion than pre-operation (23.5° versus 20.1°, p = 0.018). There were significant improvements in neck or arm VAS, JOA scores, and NDI in both groups. However, there were no differences in clinical outcomes or adverse events between the two groups.
Clinical outcomes of two-level arthroplasty and anterior cervical fusion are similar 39.6 months after surgery. Cervical arthroplasty preserves mobility at the index levels without increased adverse effects.
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.
Study design:
Prospective, multicenter, randomized Food and Drug Administration approved investigational device exemption clinical trial.
Objective:
To evaluate the safety and effectiveness of the PCM Cervical Disc compared with anterior cervical discectomy and fusion (ACDF) in the treatment of patients with degenerative spondylosis and neurological symptoms at 1 level between C3-C4 and C7-T1.
Summary of background data:
Cervical disc arthroplasty in the treatment of symptomatic cervical spondylosis has been studied in other series. The PCM Cervical Disc is a nonconstrained motion-sparing alternative to ACDF.
Methods:
Patients 18 to 65 years of age with single-level symptomatic cervical spondylosis with radiculopathy and/or myelopathy unresponsive to nonoperative treatment were enrolled, including patients with prior nonadjacent or adjacent single-level fusions. The per-protocol patient sample at 2 years included 342 patients (189 PCM, 153 ACDF). Longitudinal outcomes were comparatively evaluated.
Results:
At 2 years postoperatively, clinical measures-neck and arm pain visual analogue scale, Neck Disability Index (NDI), SF-36, and neurological status-were significantly improved from preoperative baselines in both groups. Mean NDI score at 2 years was significantly lower in PCM group (P = 0.029). There were no statistical differences between groups in rates of surgery-related serious adverse events (5.6% PCM, 7.4% ACDF) or secondary surgical procedures (5.2% PCM, 5.4% ACDF). Patients with PCM reported lower dysphagia scores (8.8/100 vs. 12.1/100; P = 0.045) and higher patient satisfaction (82.8/100 vs. 81.4/100). Overall success, a composite endpoint including minimum 20% NDI improvement, no major complications, no neurological worsening, no secondary surgical procedures, and meeting radiographical criteria of motion for PCM and fusion for ACDF, was significantly greater in the PCM group (75.1% vs. 64.9%; P = 0.020).
Conclusion:
The treatment of symptomatic single-level cervical spondylosis with PCM achieves clinical outcomes that are at least equivalent to ACDF while maintaining motion. At 2 years, patients with PCM had lower NDI scores, statistically lower rate of prolonged dysphagia, greater patient satisfaction, and superior overall success.
Object:
The goal of this study was to compare the rates of solid arthrodesis and complications following multilevel, instrumented anterior cervical fusion in patients treated with and without bone morphogenetic protein (BMP).
Methods:
The authors conducted a retrospective cohort study of patients who underwent multilevel (2+ level) anterior cervical fusions performed for degenerative disc disease with or without the concurrent use of BMP-2 from 1997 to 2012. The dosage throughout the study ranged from 2.1 to 0.26 mg/level (mean 1.0 mg/level). All patients were evaluated postoperatively by means of radiographs and CT scans to determine fusion status.
Results:
The overall fusion rate for the patients treated without BMP (n = 23) was 82.6% compared with a 100% fusion rate in the group treated with BMP (n = 22) (p = 0.04). The pseudarthrosis rates increased with number of fusion levels in patients who did not receive BMP, whereas all patients in the group treated with BMP had solid arthrodesis. Furthermore, there were 2 instrumentation failures in the non-BMP group. There was a direct correlation between the incidence of complications and the dosage of BMP used per level, with no complications reported at doses equal to or less than 1.1 mg/level.
Conclusions:
The overall rate of bony arthrodesis was increased following the use of BMP in multilevel anterior cervical fusion. Traditional methods without BMP had a high rate of pseudarthrosis. The complications associated with the use of BMP appeared to be dose related and of low incidence when BMP is used in doses equal to or less than 1.1 mg/level.
Study design:
Systematic review.Clinical questions: What is the effectiveness of multilevel cervical artificial disc replacement (C-ADR) compared with multilevel fusion with respect to pain and functional outcomes, and are the two procedures comparable in terms of safety? What is the effectiveness of multilevel C-ADR compared with single-level C-ADR with respect to pain and functional outcomes, and are the two procedures comparable in terms of safety?
Methods:
A systematic review was undertaken for articles published up to October 2011. Electronic databases and reference lists of key articles were searched to identify studies comparing multilevel C-ADR with multilevel anterior cervical discectomy and fusion (ACDF) or comparing multilevel C-ADR with single-level C-ADR. Studies which compared these procedures in the lumbar or thoracic spine or that reported alignment outcomes only were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus.
Results:
Two studies compared multilevel C-ADR with multilevel ACDF. While both reported improved Neck Disability Index (NDI) and Short-Form 36 (SF-36) scores after C-ADR compared with ACDF, only one study reported statistically significant results. Seven studies compared single-level C-ADR with multilevel C-ADR. RESULTS were similar in terms of overall success, NDI and SF-36 scores, and patient satisfaction. There is discrepant information regarding rates of heterotopic ossification; dysphagia rate may be higher in multilevel C-ADR.
Conclusions:
The literature suggests that outcomes are at least similar for multilevel C-ADR and ACDF and may favor C-ADR. Future studies are necessary before firm recommendations can be made favoring one treatment strategy. Multilevel C-ADR seems to have similar results to single-level C-ADR but may have higher rates of heterotopic ossification and dysphagia.
Purpose
Cervical disc arthroplasty has become a commonplace surgery for the treatment of cervical radiculopathy and myelopathy. Most manufacturers derive their implant dimensions from early published cadaver studies. Ideal footprint match of the prosthesis is essential for good surgical outcome.
Methods
We measured the dimensions of cervical vertebrae from computed tomography (CT) scans and to assess the accuracy of match achieved with the most common cervical disc prostheses [Bryan (Medtronic), Prestige LP (Medtronic), Discover (DePuy) Prodisc-C (Synthes)]. A total of 192 endplates in 24 patients (56.3 years) were assessed. The anterior–posterior and mediolateral diameters of the superior and inferior endplates were measured with a digital measuring system.
Results
Overall, 53.5 % of the largest device footprints were smaller in the anterior–posterior diameter and 51.1 % in the mediolateral diameter were smaller than cervical endplate diameters. For levels C5/C6 and C6/C7 an inappropriate size match was noted in 61.9 % as calculated from the anteroposterior diameter. Mismatch at the center mediolateral diameter was noted in 56.8 %. Of the endplates in the current study up to 58.1 % of C5/C6 and C6/C7, and up to 45.3 % of C3/C4 and C4/C5 were larger than the most frequently implanted cervical disc devices.
Conclusion
Surgeons and manufacturers should be aware of the size mismatch in currently available cervical disc prostheses, which may endanger the safety and efficacy of the procedure. Undersizing the prosthetic device may lead to subsidence, loosening, heterotopic ossification and biomechanical failure caused by an incorrect center of rotation and load distribution, affecting the facet joints.
Cervical arthroplasty is indicated to preserve cervical motion and prevent accelerated adjacent segment degeneration. Whether accelerated adjacent segment degeneration is prevented in the long term is unclear. This trial compared adjacent segment degeneration in Bryan disc arthroplasty with that in anterior cervical decompression and fusion five years after the surgery.
We studied patients with single level degenerative cervical disc disease. The extent of adjacent segment degeneration was estimated from lateral X-rays.
Twenty-six patients underwent single level Bryan disc arthroplasty and twenty-four patients underwent single level anterior cervical decompression and fusion. All patients were followed up for an average of sixty months. In the Bryan arthroplasty group, nine (17.6%) segments developed adjacent segment degeneration, which was significantly lower than that (60.4%) in the anterior cervical decompression and fusion group. Eleven segments in the Bryan arthroplasty group developed heterotopic ossification according to McAfee's classification and two segments had range of motion less than 2°. In the heterotopic ossification group, four (19.5%) segments developed adjacent segment degeneration, similar to the number in the non-heterotopic ossification group (16.7%). Adjacent segment degeneration rate was 50% in grade IV group but 11.8% in grade II to III.
Adjacent segment degeneration was accelerated after anterior cervical decompression and fusion. However, Bryan disc arthroplasty avoided accelerated adjacent segment degeneration by preserving motion. Patients with grade IV heterotopic ossification lost motion, and the rate of adjacent segment degeneration was higher than that in patients without heterotopic ossification.
Study design:
Systematic review.
Objective:
We performed a systematic review to determine the risk and to define potential identifiable risk factors for the development of adjacent segment pathology (ASP) after cervical fusion surgery.
Summary of background data:
During the past several decades, the indications for spinal arthrodesis have expanded, with a dramatic increase in the rate of cervical spine fusion in the United States during the past decade. However, as more of these procedures are performed over time, there have been concerns regarding the potential for these patients to develop changes at levels adjacent to the index procedure. Questions remain whether the development of clinical ASP (CASP) are iatrogenic in nature or part of natural history.
Methods:
A systematic review of the literature was undertaken for articles published in English language between 1990 and March 15, 2012. Electronic databases and reference lists of key articles were searched to identify articles reporting risk factors for CASP after cervical fusion. Two independent reviewers assessed the level of evidence and the overall quality of the literature using the Grades of Recommendation Assessment, Development, and Evaluation criteria. Disagreements were resolved by consensus.
Results:
We identified 5 studies (4 retrospective cohorts, 1 database study) from our search strategy that met the inclusion criteria from a total of 176 possible studies for review. The prevalence of CASP ranged from 11% to 12% at 5 years, 16% to 38% at 10 years, and 33% at 17 years. Factors that may contribute to the development of CASP include age less than 60 years, fusing adjacent to the C5-C6 and/or C6-C7 levels, a pre-existing disc herniation, and/or dural compression secondary to spinal stenosis with a mean anteroposterior diameter spinal canal of 13 mm or smaller.
Conclusion:
CASP remains a controversial topic despite multiple attempts of elucidating an iatrogenic effect of spinal fusion versus the natural history of spinal degeneration. The mean rate of the development of symptomatic degeneration in the cervical spine after arthrodesis is estimated between 1.6% and 4.2% per year. The mean rate of reoperation for CASP is estimated at 0.8% per year. In addition, fusing adjacent to but not including the C5-C6 and/or C6-C7 disc spaces seems to consistently increase the risk of developing CASP.
Consensus statement:
1. The risk of developing new symptoms secondary to adjacent segment pathology causing radiculopathy and/or myelopathy after cervical fusion surgery ranges from a cumulative rate of 1.6% to 4.2% per year. Strength of Statement: Strong. 2. The risk of developing adjacent-level symptoms may be increased if disc protrusion, disc degeneration, or cord effacement is present at C5–C6 and/or C6–C7 and if those levels are adjacent to the planned surgical level. Strength of Statement: Strong.
Study design:
Retrospective cohort study.
Objective:
To investigate the differences between single- and multilevel degenerative disc diseases (DDDs) treated with cervical arthroplasty.
Summary of background data:
The US Food and Drug Administration clinical trials compared arthroplasty with anterior cervical discectomy and fusion for single-level DDD. However, cervical arthroplasty for multilevel DDD is rarely addressed in the literature.
Methods:
A total of 102 consecutive patients who underwent Bryan arthroplasty were divided into either a single- or multilevel group. Clinical outcomes were measured by the visual analogue scale (VAS) of neck and arm, and by the neck disability index with a minimum follow-up of 25 months. Every patient had radiographical evaluations, and computed tomography.
Results:
Eighty-six patients (84.3%) completed the follow-up with a mean time of 38.3 ± 8.7 months. Postoperatively, there were significant improvements in clinical outcomes (i.e., VAS neck, VAS arm, and neck disability index) at each time point of evaluation (i.e., 3-, 6-, 12-, and 24 mo postoperation). The sex composition and clinical outcome improvements between the single- and multilevel groups were not significantly different. The multilevel group was older (51.3 ± 8.6 vs. 46.3 ± 11.2 yr; P = 0.02), had more intraoperative blood loss (218.0 ± 182.4 vs. 102.8 ± 79.2 mL; P = 0.001), and demonstrated a higher rate of heterotopic ossification (HO) than the single-level group (66.0% vs. 25.0%; P < 0.001). The majority (97.7%) of the artificial discs in this series remained mobile despite HO.
Conclusion:
Clinical outcomes of cervical arthroplasty in multilevel spondylosis are similar to single-level outcomes. However, the significantly higher rate of HO found in multilevel arthroplasty and its long-term effect warrant further investigation.
The most currently accepted indication for cervical arthroplasty is 1- or 2-level degenerative disc disease (DDD) refractory to medical treatment. However, the randomized and controlled clinical trials by the US FDA investigational device exemption studies only compared cervical arthroplasty with anterior cervical discectomy and fusion for 1-level disease. Theoretically, 2-level cervical spondylosis usually implicates more advanced degeneration, whereas the 1-level DDD can be caused by merely a soft-disc herniation. This study aimed to investigate the differences between 1- and 2-level cervical arthroplasty.
The authors analyzed data obtained in 87 consecutive patients who underwent 1- or 2-level cervical arthroplasty with Bryan disc. The patients were divided into the 1-level and the 2-level treatment groups. Clinical outcomes were measured using the visual analog scale (VAS) for the neck and arm pain and the Neck Disability Index (NDI), with a minimum follow-up of 30 months. Radiographic outcomes were evaluated on both radiographs and CT scans.
The study analyzed 98 levels of Bryan cervical arthroplasty in 70 patients (80.5%) who completed the evaluations in a mean follow-up period of 46.21 ± 9.85 months. There were 22 females (31.4%) and 48 males (68.6%), whose mean age was 46.57 ± 10.07 years at the time of surgery. The 1-level group had 42 patients (60.0%), while the 2-level group had 28 patients (40.0%). Patients in the 1-level group were younger than those in the 2-level group (mean 45.00 vs 48.93 years, p = 0.111 [not significant]). Proportional sex compositions and perioperative prescription of nonsteroidal antiinflammatory drugs were also similar in both groups (p = 0.227 and p = 1.000). The 2-level group had significantly greater EBL during surgery than the 1-level group (220.80 vs 111.89 ml, p = 0.024). Heterotopic ossification was identified more frequently in the 2-level group than the 1-level group (75.0% vs 40.5%, p = 0.009). Although most of the artificial discs remained mobile during the follow up, the 2-level group had fewer mobile discs (100% and 85.7%, p = 0.022) than the 1-level group. However, in both groups, the clinical outcomes measured by VAS for neck pain, VAS for arm pain, and NDI all significantly improved after surgery compared with that preoperatively, and there were no significant differences between the groups at any point of evaluation (that is, at 3, 6, 12, and 24 months after surgery).
Clinical outcomes of 1- and 2-level cervical arthroplasty were similar at 46 months after surgery, and patients in both groups had significantly improved compared with preoperative status. However, there was a significantly higher rate of heterotopic ossification formation and less mobility of the Bryan disc in patients who underwent 2-level arthroplasty. Although mobility to date has been maintained in the vast majority (94.3%) of patients, the long-term effects of heterotopic ossification warrant further investigation.
Cervical total disc replacement (CTDR) represents a relatively novel procedure intended to address some of the shortcomings associated with anterior cervical discectomy and fusion (ACDF) by preserving motion at the treated level. This prospective, randomized, multicenter study evaluates the safety and efficacy of a new metal-on-metal CTDR implant (Kineflex|C) by comparing it with ACDF in the treatment of single-level spondylosis with radiculopathy.
The study was a prospective, randomized US FDA Investigational Device Exemption (IDE) pivotal trial conducted at 21 centers across the US. The primary clinical outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS) scores, and a composite measure of clinical success. Patients were randomized to CTDR using the Kineflex|C (SpinalMotion, Inc.) cervical artificial disc or ACDF using structural allograft and an anterior plate.
A total of 269 patients were enrolled and randomly assigned to either CTDR (136 patients) or to ACDF (133 patients). There were no significant differences between the CTDR and ACDF groups when comparing operative time, blood loss, length of hospital stay, or the reoperation rate at the index level. The overall success rate was significantly greater in the CTDR group (85%) compared with the ACDF group (71%) (p = 0.05). In both groups, the mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the 24-month follow-up (p < 0.0001). Similarly, the VAS pain scores improved significantly by 6 weeks and remained significantly improved through the 24-month follow-up (p < 0.0001). The range of motion (ROM) in the CTDR group decreased at 3 months but was significantly greater than the preoperative mean at 12- and 24-month follow-up. The ROM in the ACDF group was significantly reduced by 3 months and remained so throughout the follow-up. Adjacent-level degeneration was also evaluated in both groups from preoperatively to 2-year follow-up and was classified as none, mild, moderate, or severe. Preoperatively, there were no significant differences between groups when evaluating the different levels of adjacent-level degeneration. At the 2-year follow-up, there were significantly more patients in the ACDF group with severe adjacent-level radiographic changes (p < 0.0001). However, there were no significant differences between groups in adjacent-level reoperation rate (7.6% for the Kineflex|C group and 6.1% for the ACDF group).
Cervical total disc replacement allows for neural decompression and clinical results comparable to ACDF. Kineflex|C was associated with a significantly greater overall success rate than fusion while maintaining motion at the index level. Furthermore, there were significantly fewer Kineflex|C patients showing severe adjacent-level radiographic changes at the 2-year follow-up. These results from a prospective, randomized study support that Kineflex|C CTDR is a viable alternative to ACDF in select patients with cervical radiculopathy.
Heterotopic ossification (HO) after cervical total disc replacement (TDR) has been reported to impede artificial disc motion. In all previously reported cases of HO, assessment was based on plain radiographs. The authors hypothesized that CT scan is a more sensitive and accurate detector. The aims of this study were to assess the actual incidence of HO and its effect on outcome in a cohort of patients undergoing cervical TDR with the Bryan disc and to compare HO detection by means of plain radiographs and CT.
The authors retrospectively assessed data from medical records, radiological studies, and clinical evaluations of patients who underwent 1- or 2-level cervical TDR with the Bryan disc and were followed up for more than 12 months. The presence and grading of HO according to the McAfee classification were assessed by CT scan, and these findings were compared with findings on plain radiographs. Thirty-six patients (mean age 46.61 ± 7.24 years; range 29-60 years; 21 men and 15 women) who underwent Bryan TDR at 52 levels were included in the study. The mean duration of CT follow-up was 19.03 ± 4.64 months; the mean duration of clinical follow-up was 26.78 ± 7.20 months.
On the basis of CT, HO was identified in 18 (50%) of 36 patients and 25 (48.1%) of 52 levels treated. Grade 1 HO was present in 9 of the levels treated (17.3%), Grade 2 in 13 levels (25.0%), Grade 3 in 2 levels (3.8%), and Grade 4 in 1 level (1.9%). Nineteen (76%) of the 25 affected levels were in patients who had undergone 2-level TDR. There was no significant association with patient sex or disc pathology. There was a tendency for HO development among older patients, but this finding was not statistically significant (mean age 48.8 ± 6.8 in patients with HO vs 44.4 ± 7.2 in those without HO, p = 0.065). Although HO was found in 25 levels, 96.2% of the treated levels (50 of 52) had segmental range of motion on dynamic (flexion and extension) radiographs. The concordance between HO grading by CT and radiography was high, with an intraclass correlation coefficient of 0.822 (lower limit of 95% CI: 0.710, p < 0.001). Patients who had HO had the same clinical success rate as those who did not (94.4% vs 94.4%, p = 1.00). The visual analog scale scores for neck and arm pain were significantly improved in both the HO and the non-HO group.
The rate of HO detected by CT scan in this cohort of patients undergoing cervical TDR with a Bryan disc was 48.1% per level treated and 50% per patient with minimal limitation of segmental motion (96.2% of levels remained mobile), but plain radiograph is an acceptable detection tool. Two-level surgery has a higher risk of HO, although development of HO does not affect clinical outcome.
In this study, the authors review the technique for inserting the Prestige ST in a contiguous multilevel cervical disc arthroplasty in patients with radiculopathy and myelopathy. They describe the preoperative planning, surgical technique, and their experience with 10 patients receiving a contiguous Prestige ST implant. They present contiguous multilevel cervical arthroplasty as an alternative to multilevel arthrodesis.
After institutional board review approval was obtained, the authors performed a retrospective review of all contiguous multilevel cervical disc arthroplasties with the Prestige ST artificial disc between August 2007 and November 2009 at a single institution by a single surgeon. Clinical criteria included patients who had undergone a multilevel cervical disc arthroplasty performed for radiculopathy and myelopathy without the presence of a previous cervical fusion. Between August 2007 and November 2009, 119 patients underwent cervical arthroplasty. Of the 119 patients, 31 received a Hybrid construct (total disc resection [TDR]-anterior cervical decompression and fusion [ACDF] or TDR-ACDF-TDR) and 24 received a multilevel cervical arthroplasty. The multilevel cervical arthroplasty group consisted of 14 noncontiguous and 10 contiguous implants. This paper examines patients who received contiguous Prestige ST implants.
Ten men with an average age of 45 years (range 25-61 years) were treated. Five patients presented with myelopathy, 3 presented with radiculopathy, and 2 presented with myeloradiculopathy. Twenty-two 6 x 16-mm Prestige ST TDRs were implanted. Six patients received 2-level Prestige ST implants. Five patients received TDRs at C5-6 and C6-7, and 1 patient received TDRs at C3-4 and C4-5. One patient received a TDR at C3-4, C5-6, and C6-7 where C4-5 was a congenital block vertebra. Three patients (2 with 3-level disease and 1 with 4-level disease) received contiguous Prestige ST implants as well as a Prevail ACDF as part of their constructs. The mean clinical and radiographic follow-up was 12 months. There has been no case of screw backout, implant dislodgment, progressive kyphosis, formation of heterotopic bone, evidence of pseudarthrosis at the Prevail levels, or development of symptomatic adjacent level disease.
Multilevel cervical arthroplasty with the Prestige ST is a safe and effective alternative to fusion for the management of cervical radiculopathy and myelopathy.
In this study, long-term results are presented from clinical studies of the Bryan Cervical Disc Prosthesis at University Hospital Gasthuisberg in Leuven, Belgium. A total of 98 patients (89 with 1-level and 9 with 2-level implantations) agreed to participate in follow-up studies for up to 10 years postoperatively. This article focuses on the 4- and 6-year results. Patients in one of the clinical studies had either radiculopathy or myelopathy associated with spondylosis and/or disc herniations that did not respond to conservative treatment. Patients from the other clinical study received commercially available Bryan devices and the study protocol did not have specific inclusion/exclusion criteria. More than 90% of the patients were considered to have radiculopathy.
Clinical measurements discussed in the article include the 36-Item Short Form Health Survey, Neck Disability Index, numerical ratings of neck and arm pain, neurological outcomes, and Odom classification. Angular motion findings from lateral flexion-extension radiographs are also presented. The occurrence of adverse events and second surgeries are examined as an indicator of device safety.
The clinical outcomes at 4 and 6 years postoperatively appear consistent with the previously reported results at 1 and 2 years postoperatively. The mean angular motion results at 4 and 6 years postoperatively for 1-level patients were 7.3 and 7.7 degrees, respectively. Two-level patients had slightly less motion at 4 and 6 years postoperatively with mean caudad values of 5.7 and 6.0 degrees, respectively, and cephalad values of 4.2 and 6.2 degrees, respectively. Efforts were made to capture adverse events, regardless of their nature and relatedness to the study surgery. This effort resulted in a relatively high number of recorded events. However, only 6 patients experienced events that were judged by the investigator to be related, either possibly or definitely, to the Bryan device. These events included device migration, device removal, and hoarseness and vocal cord paralysis, as well as 3 cases involving pain and neurological symptoms. Eight patients underwent further neck surgery to treat symptoms.
The favorable clinical and angular motion outcomes that were previously noted at 1- and 2-years' follow-up after cervical disc replacement with the Bryan Cervical Disc Prosthesis appear to persist after 4 and 6 years of follow-up.
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.
In this prospective study, our aim was to compare the functional results and radiographic outcomes of fusion and Bryan Cervical Disc replacement in the treatment of two-level cervical disc disease. A total of 65 patients with two-level cervical disc disease were randomly assigned to two groups, those operated on with Bryan Cervical Disc replacement (31) and those operated on with anterior cervical fusion with an iliac crest autograft and plate (34). Clinical evaluation was carried out using the visual analogue scale (VAS), the Short Form 36 (SF-36) and the neck disability index (NDI) during a two year follow-up. Radiological evaluation sought evidence of range of motion, stability and subsidence of the prosthesis. Substantial reduction in NDI scores occurred in both groups, with greater percent improvement in the Bryan group (P = 0.023). The arm pain VAS score improvement was substantial in both groups. Bryan artificial cervical disc replacement seems reliable and safe in the treatment of patients with two-level cervical disc disease.
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.
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)
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.
A prospective study of 15 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at three or four operative levels stabilized with an unicortical anterior plate.
To provide medium-term follow-up data on the surgical success and patient outcome of three- and four-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on the results.
The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. The arthrodesis rate and outcome for patients having three- and four-level discectomy and fusion procedures is disappointing. Internal fixation putatively improves these parameters.
Fifteen patients (average age, 51 years; range, 35-77), were observed for an average of 42 months (range, 25-73) All had an anterior discectomy, burring of the endplates, placement of an autogenous tricortical iliac crest graft at three (12 patients) or four (3 patients) levels, and application of a Cervical Spine Locking Plate. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief, and neurologic recovery were evaluated.
Solid arthrodesis was achieved at all levels in only 7 (47%) of the 15 patients after a single procedure. Of the 8 patients with pseudarthrosis, 3 had sufficient pain to necessitate revision surgery (with pain relief in two), 1 had pain without further surgery, and 4 no pain. Of the 7 with solid fusion, 3 had persistent pain, and 4 had none. Two in this group had a second procedure. All 4 patients with preoperative myelopathy improved, and 10 of the 11 with radiculopathy had resolution of arm symptoms.
Three- and four-level modified Robinson cervical discectomy and fusion results in an unacceptably high rate of pseudarthrosis. The Cervical Spine Locking Plate alone does not appear to improve the arthrodesis rate.
A biomechanical study was performed using cadaveric cervical spine specimens.
To determine the effect of cervical spine fusion on adjacent-level intradiscal pressure.
Clinical studies have reported that patients with spinal fusion are at greater risk of pathology and early disc degeneration at adjacent levels. It is hypothesized that eliminating motion at one level leads to hypermobility and increased forces at adjacent levels, thus increasing the rate of disc degeneration.
Six cadaveric cervical spine specimens were tested. Specimens were stabilized at T1 and loaded at C3 to 20 degrees of flexion and 15 degrees of extension. Intradiscal pressures and segmental motion at C4-C5 and C6-C7 were recorded first on intact specimens, and then after anterior cervical plating at C5-C6. Changes in intradiscal pressure and segmental motion were calculated and statistically analyzed using a paired Student t test.
Intradiscal pressures were significantly increased during flexion at both adjacent levels. The pressure increased by 73.2% at C4-C5 (P = 0.002), and by 45.3% at C6-C7 (P = 0.006). Intradiscal pressures increased at both adjacent levels during extension, but not significantly. During flexion, segmental motion increased at both adjacent levels, with greater increases at C4-C5. During extension, segmental motion increased at both adjacent levels, with greater increases at C6-C7.
Clinical studies have reported increased rates of disc degeneration at levels adjacent to fusion. It is believed that eliminating motion through fusion shifts the load to the adjacent levels, causing earlier disc degeneration. This study has shown that significant increases in intradiscal pressure and segmental motion occur at levels adjacent to fusion during normal range of motion. These results may partially explain the mechanism of early disc degeneration at levels adjacent to cervical spine fusion.
The aim of this work was to add to the body of data on the frequency and severity of degenerative radiographic findings at adjacent levels after anterior cervical interbody fusion and on their clinical impact and to contribute to the insights about their pathogenesis. One hundred eighty patients who were treated by anterior cervical interbody fusion and who had a follow-up of >60 months were clinically and radiologically examined by independent investigators. For all patients, the long-term Odom score was compared with the score as obtained 6 weeks after surgery. For myelopathic cases, both the late Nurick and the Odom score were compared with the initial postoperative situation. For the adjacent disc levels, a radiologic "degeneration score" was defined and assessed both initially and at long-term follow-up. At late follow-up after anterior cervical interbody fusion, additional radiologic degeneration at the adjacent disc levels was found in 92% of the cases, often reflecting a clinical deterioration. The severity of this additional degeneration correlated with the time interval since surgery. The similarity of progression to degeneration between younger trauma patients and older nontrauma patients suggests that both the biomechanical impact of the interbody fusion and the natural progression of pre-existing degenerative disease act as triggering factors for adjacent level degeneration.
Given the number of spinal fusions performed annually, concerns have mounted over the potential for adjacent segment degeneration (radiographic changes of degeneration at levels adjacent to a spinal fusion) and adjacent segment disease (development of new symptoms correlating with adjacent segment degeneration). This article reviews documented evidence on adjacent segment degeneration and disease as it relates to cervical and lumbar arthrodesis. There appears to be an incidence of adjacent segment degeneration and disease after arthrodesis that may be related to natural degeneration or the adjacent fusion. It remains to be seen whether restoration of motion with disc arthroplasty will alter the rate of adjacent segment degeneration or disease.
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.
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.
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.
Review of clinical file information and postoperative imaging, collected prospectively over a period of 14 years, in anticipation of study.
1) Assessment of technical success in achieving anterior cervical fusion without internal fixation; 2) assessment of postoperative neck pain relevant to technical success or failure of fusion; and 3) assessment of morbidity arising from iliac crest bone graft donor site.
After anterior cervical discectomy and bone grafting for cervical radiculopathy or the intractable pain of cervical spondylosis, common clinical practice varies widely between the extremes of internal fixation in all cases, and never applying fixation. The clinical information and relevant imaging of 97 consecutive patients, 46 male, was reviewed at 12 months after surgery.
All surgery was performed at no more than 2 contiguous levels, by one surgeon (S.M.E.). After anterior discectomy alone, or combined with posterior vertebral body margin osteophytectomy, anterior bone grafting (Smith-Robinson) was performed at each level using a tricortical autogenous iliac crest bone block inserted under compression. In the interests of maximizing resource allocation and minimizing potential complications, all surgery was completed without internal fixation. A postoperative semirigid cervical collar was prescribed for 2 months.
In 54 patients having 1-level fusion, there were 6 pseudarthroses (11%). In 43 patients having 2-level fusion, 12 patients demonstrated pseudarthroses (28% of patients) at a total of 18 levels (21% of levels). Only 2 of the 97 patients had pain related to the donor site.
These results tend to confirm published reports of high pseudarthrosis rates in anterior cervical fusions carried out at 2 or more levels without fixation, as against improved fusion rates when internal fixation is applied. The authors are inclined to change their practice to include internal fixation in the form of anterior plating for fusions carried out at more than one level. Patients with technically successful fusions were less likely to have postoperative neck pain. Donor site pain was not a significant postoperative complication.
Class 2 level of evidence: This is a prospective, consecutive series of 229 prosthetic implantations that were concurrently enrolled between single-level versus multilevel cervical arthroplasty comprising an FDA Pilot Study.
This study investigated multilevel cervical disc replacement in relation to single-level cervical arthroplasty to find if the same reduction in clinical success would occur with this alternative treatment.
Usually, the clinical outcomes of instrumented cervical fusions deteriorate as the number of vertebral levels of involvement increases.
A total of 229 patients presented with cervical herniated nucleus pulposus, cervical spondylosis, and/or adjacent segment disease with cervical radiculopathy or myelopathy. Following anterior cervical neurologic decompression seventy-one patients required porous coated motion (PCM) cervical arthroplasties from C3-C4 to C7-T1 (Group S, single level). Sixty-nine patients underwent 158 multilevel PCM cervical arthroplasties (Group M, multilevel) during the same time interval, for the same indications, performed by the same surgeons under the same clinical protocol: double level, 53 cases; three levels, 12 cases: and 4 levels, 4 cases.
The self-assessment outcomes instruments showed significantly more improvement for the multilevel cases. The mean improvement in the NDI for the single cases was 37.6% versus the multilevel cases mean improvement in NDI was 52.6% (P = 0.021). The difference between the two was statistically significant. The mean improvement in the VAS showed the same association: single-level mean improvement 58.4% versus the multilevel cases mean VAS improvement was 65.9%. The Odom's were also more improved for the multilevel versus the single-level group: 93.9% versus 90.5% in the excellent, good, and fair categories. The reoperation rates and serious adverse events were similar between the single-level (S = 3) to the multilevel arthroplasty (M = 2) groups. Kaplan-Meier implant survivorship analysis at 3 years for the cohort of 229 prostheses was 94.5% (confidence interval, 1.00-0.820).
This prospective study of cervical arthroplasty is the first report to date showing significantly improved clinical outcomes for multilevel cervical arthroplasty compared with single-level cervical disc replacement using an FDA validated outcome instrument.
Symptomatic multisegment disease is most common at the C5-6 and C6-7 levels, and two-level anterior cervical discectomy and fusion (ACDF) is performed most often at these levels. Therefore, it may be clinically important to know whether a C5-7 fusion affects the superior C4-5 segment. A biomechanical study was carried out using cadaveric cervical spine specimens to determine the effect of lower two-level anterior cervical fusion on intradiscal pressure and segmental motion at the superior adjacent vertebral level.
Five cadaveric cervical spine specimens were used in this study. The specimens were stabilized at T-1 and loaded at C-3 to 15 degrees flexion, 10 degrees extension, and 10 degrees lateral bending before and after simulated two-level ACDF with plate placement at C5-7. Intradiscal pressure was recorded at the C4-5 level, and segmental motion was recorded from C-4 through C-7. Differences in mean intradiscal pressures were calculated and analyzed using a paired Student t-test. When the maximum calibrated intradiscal pressures were exceeded ("overshot") during measurements, data from the specimens involved were analyzed using the motion data with a Student t-test. Values for pressure and motion obtained before and after simulated ACDF were compared.
During flexion, the mean intradiscal pressure changes (+/- standard deviations) in the pre- and post-ACDF measurements were 1275 (+/- 225) mm Hg and 2475 (+/- 75) mm Hg, respectively (p < 0.05). When the results of pre-ACDF testing were compared with post-ACDF results, no significant difference was found in the mean changes in the intradiscal pressure during extension and lateral bending. The maximum calibrated intradiscal pressures were exceeded during the post-ACDF testing in four specimens in extension, three in flexion, and two in lateral bending. Comparison of pre- and post-ACDF data for all five specimens revealed significant differences in motion and intradiscal pressure (p < 0.05) during flexion, significant differences in motion (p < 0.05) but not in intradiscal pressure during extension, and significant differences in intradiscal pressure changes (p < 0.05) but not in motion during lateral bending.
Simulated C5-7 ACDF caused a significant increase in intradiscal pressure and segmental motion in the superior adjacent C4-5 level during physiological motion. The increased pressure and hypermobility might accelerate normal degenerative changes in the vertebral levels adjacent to the anterior cervical fusion.
Abbreviation: CDA, cervical disc arthroplasty. 1-Level Versus 2-Level Treatment With Cervical Disc Arthroplasty or Fusion cervical allograft arthrodesis and instrumentation: multilevel interbody grafting or strut graft reconstruction
Abbreviation: CDA, cervical disc arthroplasty.
1-Level Versus 2-Level Treatment With Cervical Disc Arthroplasty or Fusion
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