Rick C Sasso

Toronto Western Hospital, Toronto, Ontario, Canada

Are you Rick C Sasso?

Claim your profile

Publications (117)199.97 Total impact

  • Spine 07/2014; 39(15):1265. · 2.45 Impact Factor
  • Journal of neurosurgery. Spine 03/2014; DOI:10.3171/2013.11.SPINE13850 · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Study Design Post hoc analysis of prospective, randomized trial. Objective To investigate the disability associated with driving and single-level degenerative, cervical disc disease and to investigate the effect of surgery on driving disability. Methods Post hoc analysis of data obtained from three sites participating in a multicenter, randomized, controlled trial comparing cervical disc arthroplasty (TDA) with anterior cervical discectomy and fusion (ACDF). The driving subscale of the Neck Disability Index (NDI) was analyzed for all patients. A dichotomous severity score was created from the NDI. Statistical comparisons were made within and between groups. Results Two-year follow-up was available for 118/135 (87%) patients. One half of the study population (49.6%) reported moderate or severe preoperative driving difficulty. This disability associated with driving was similar among the two groups (ACDF: 2.5 ± 1.1, TDA: 2.6 ± 1.0, p = 0.646). The majority of patients showed improvement, with no or little driving disability, at the sixth postoperative week (ACDF: 75%, TDA: 90%, p = 0.073). At no follow-up point did a difference exist between groups according to the severity index. Conclusions Many patients suffering from radiculopathy or myelopathy from cervical disc disease are limited in their ability to operate an automobile. Following anterior cervical spine surgery, most patients are able to return to comfortable driving at 6 weeks.
    12/2013; 3(4):237-42. DOI:10.1055/s-0033-1354250
  • [Show abstract] [Hide abstract]
    ABSTRACT: Retrospective, multicenter review of 96 patients who underwent L5-S1 interbody fusions through either a standard anterior retroperitoneal approach or using a novel device inserted through the presacral space (AxiaLIF) in conjunction with supplemental posterior fixation between 2002 and 2010. To compare the radiographic fusion rates and adverse events associated with anterior lumbar interbody fusion (ALIF) and AxiaLIF techniques. Interbody fusions of the lumbosacral spine are frequently performed to provide anterior column support, increase the amount of surface area for bone formation, and facilitate deformity reduction. A number of different surgical approaches have been developed for this purpose including minimally invasive techniques. Patient information and procedural data were obtained from hospital charts. Multiplanar CT images were evaluated by 2 independent observers to assess fusion success at 24 months using a 4-point grading scale. In addition to reviewing the medical records to identify any complications, all of the sites were queried regarding any device-related adverse events that may have occurred. According to the radiographic analysis, the arthrodesis rates recorded for the ALIF and AxiaLIF cohorts were 79% and 85%, respectively (P>0.05). The numbers and types of adverse events recorded for these procedures appeared to be similar although there was one serious intraoperative complication (iliac artery laceration) noted in the ALIF group. The radiographic success and adverse events associated with AxiaLIF appear to be similar to that observed for ALIF, suggesting that this technique represents a safe and effective method for achieving an interbody fusion across the L5-S1 disc space when utilized in conjunction with posterior fixation.
    Journal of spinal disorders & techniques 11/2013; DOI:10.1097/BSD.0b013e318292aad7 · 1.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Study Design. A prospective observational multicenter study.Objective. To help solve the debate regarding whether the anterior or posterior surgical approach is optimal for patients with cervical spondylotic myelopathy (CSM)Summary of Background Data. The optimal surgical approach to treat CSM remains debated with varying opinions favoring anterior vs posterior surgical approaches. We present an analysis of a prospective observational multicenter study examining outcomes of surgical treatment for CSM.Methods. 278 subjects from 12 sites in NA received anterior/posterior or combined surgery at the discretion of the surgeon. This study focused on subjects who had either anterior or posterior surgery (n = 264, 87% follow-up rate). Outcome measures included the Modified Japanese Orthopedic Assessment Scale (mJOA), the Nurick scale, the Neck Disability Index (NDI) and the SF36v2 Physical (PCS) and Mental (MCS) Component Scores.Results. 169 patients were treated anteriorly while 95 received posterior surgery. Anterior surgical cases were younger and had less severe myelopathy as assessed by mJOA and Nurick scores. There were no baseline differences in NDI or SF36 between the anterior and posterior cases. Improvement in the mJOA was significantly lower in the anterior group when compared to posterior group (2.47 vs. 3.62, respectively, P < .01), although the groups started at different levels of baseline impairment. The extent of improvement in the Nurick, NDI, SF36v2 PCS, SF36v2 MCS scores did not differ between groups.Conclusion. Patients with CSM show significant improvements in several health related outcome measures with either anterior or posterior surgery. Importantly, patients treated with anterior techniques were younger, with less severe impairment and more focal pathology. We demonstrate for the first time that, when patient and disease factors are controlled for, anterior and posterior surgical techniques have equivalent efficacy in the treatment of CSM.
    Spine 10/2013; 38(26). DOI:10.1097/BRS.0000000000000047 · 2.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cervical spondylotic myelopathy is the leading cause of spinal cord dysfunction worldwide. The objective of this study was to evaluate the impact of surgical decompression on functional, quality-of-life, and disability outcomes at one year after surgery in a large cohort of patients with this condition. Adult patients with symptomatic cervical spondylotic myelopathy and magnetic resonance imaging evidence of spinal cord compression were enrolled at twelve North American centers from 2005 to 2007. At enrollment, the myelopathy was categorized as mild (modified Japanese Orthopaedic Association [mJOA] score ≥ 15), moderate (mJOA = 12 to 14), or severe (mJOA < 12). Patients were followed prospectively for one year, at which point the outcomes of interest included the mJOA score, Nurick grade, Neck Disability Index (NDI), and Short Form-36 version 2 (SF-36v2). All outcomes at one year were compared with the preoperative values with use of univariate paired statistics. Outcomes were also compared among the severity classes with use of one-way analysis of variance. Finally, a multivariate analysis that adjusted for baseline differences among the severity groups was performed. Treatment-related complication data were collected and the overall complication rate was calculated. Eighty-five (30.6%) of the 278 enrolled patients had mild cervical spondylotic myelopathy, 110 (39.6%) had moderate disease, and 83 (29.9%) had severe disease preoperatively. One-year follow-up data were available for 222 (85.4%) of 260 patients. There was a significant improvement from baseline to one year postoperatively (p < 0.05) in the mJOA score, Nurick grade, NDI score, and all SF-36v2 health dimensions (including the mental and physical health composite scores) except general health. With the exception of the change in the mJOA, the degree of improvement did not depend on the severity of the preoperative symptoms. These results remained unchanged after adjusting for relevant confounders in the multivariate analysis. Fifty-two patients experienced complications (prevalence, 18.7%), with no significant differences among the severity groups. Surgical decompression for the treatment of cervical spondylotic myelopathy was associated with improvement in functional, disability-related, and quality-of-life outcomes at one year of follow-up for all disease severity categories. Furthermore, complication rates observed in the study were commensurate with those in previously reported cervical spondylotic myelopathy series. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 09/2013; 95(18):1651-8. DOI:10.2106/JBJS.L.00589 · 4.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Object Although smoking has been shown to negatively affect fusion rates in patients undergoing multilevel fusions of the cervical and lumbar spine, the effect of smoking on fusion rates in patients undergoing single-level anterior cervical discectomy and fusion (ACDF) with allograft and plate fixation has yet to be thoroughly investigated. The objective of the present study was to address the effect of smoking on fusion rates in patients undergoing a 1-level ACDF with allograft and a locked anterior cervical plate. Methods This study is composed of patients from the control groups of 5 separate studies evaluating the use of an anterior cervical disc replacement to treat cervical radiculopathy. For each of the 5 studies the control group consisted of patients who underwent a 1-level ACDF with allograft and a locked cervical plate. The authors of the present study reviewed data obtained in a total of 573 patients; 156 patients were smokers and 417 were nonsmokers. A minimum follow-up period of 24 months was required for inclusion in this study. Fusion status was assessed by independent observers using lateral, neutral, and flexion/extension radiographs. Results An overall fusion rate of 91.4% was achieved in all 573 patients. A solid fusion was shown in 382 patients (91.6%) who were nonsmokers. Among patients who were smokers, 142 (91.0%) had radiographic evidence of a solid fusion. A 2-tailed Fisher exact test revealed a p value of 0.867, indicating no difference in the union rates between smokers and nonsmokers. Conclusions The authors found no statistically significant difference in fusion status between smokers and nonsmokers who underwent a single-level ACDF with allograft and a locked anterior cervical plate. Although the authors do not promote tobacco use, it appears that the use of allograft with a locked cervical plate in single-level ACDF among smokers produces similar fusion rates as it does in their nonsmoking counterparts.
    Journal of neurosurgery. Spine 08/2013; DOI:10.3171/2013.7.SPINE13208 · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cervical spondylotic myelopathy (CSM) is a chronic spinal cord disease and can lead to progressive or stepwise neurologic decline. Several factors may influence this process, including extent of spinal cord compression, duration of symptoms, and medical comorbidities. Diabetes is a systemic disease that can impact multiple organ systems, including the central and peripheral nervous systems. There has been little information regarding the effect of diabetes on patients with coexistent CSM. To provide empirical data regarding the effect of diabetes on treatment outcomes in patients who underwent surgical decompression for coexistent CSM. Large prospective multicenter cohort study of patients with and without diabetes who underwent decompressive surgery for CSM. Two hundred thirty-six patients without and 42 patients with diabetes were enrolled. Of these, 37 were mild cases and five were moderate cases. Four required insulin. There were no severe cases associated with end-organ damage. Self-report measures include Neck Disability Index and version 2 of 36-Item Short Form Health Survey (SF-36v2), and functional measures include modified Japanese Orthopedic Association (mJOA) score and Nurick grade. We compared presurgery symptoms and treatment outcomes between patients with and without diabetes using univariate and multivariate models, adjusting for demographics and comorbidities. Diabetic patients were older, less likely to smoke, and more likely to be on social security disability insurance. Patients with diabetes presented with a worse Nurick grade, but there were no differences in mJOA and SF-36v2 at presentation. Overall, there was a significant improvement in all outcome parameters at 12 and 24 months. There was no difference in the level of improvement between the patients with and without diabetes, except in the SF-36v2 Physical Functioning, in which diabetic patients experienced significantly less improvement. There were no differences in surgical complication rates between diabetic patients and nondiabetic patients. Except for a worse Nurick grade, diabetes does not seem to affect severity of symptoms at presentation for surgery. More importantly, with the exception of the SF-36v2 Physical Functioning scores, outcomes of surgical treatment are similar in patients with diabetes and without diabetes. Surgical decompression is effective and should be offered to patients with diabetes who have symptomatic CSM and are appropriate surgical candidates.
    The spine journal: official journal of the North American Spine Society 08/2013; 14(1). DOI:10.1016/j.spinee.2013.06.016 · 2.90 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dens fractures are relatively common in the elderly. The treatment of Type-II dens fractures remains controversial. The aim of this multicenter prospective cohort study was to compare outcomes (assessed with use of validated clinical measures) and complications of nonsurgical and surgical treatment of Type-II dens fractures in patients sixty-five years of age or older. One hundred and fifty-nine patients with a Type-II dens fracture were enrolled in a multicenter prospective study. Subjects were treated either surgically (n = 101) or nonsurgically (n = 58) as determined by the treatment preferences of the treating physicians and the patients. The subjects were followed at six and twelve months with validated outcome measures, including the Neck Disability Index (NDI) and Short Form-36v2 (SF-36v2). Treatment complications were prospectively recorded. Statistical analysis was performed to compare outcome measures before and after adjustment for confounding variables. The two groups were similar with regard to baseline characteristics. The most common surgical treatment was posterior C1-C2 arthrodesis (eighty of 101, or 79%) while the most common nonsurgical treatment was immobilization with use of a hard collar (forty-seven of fifty-eight, or 81%). The overall mortality rate was 18% over the twelve-month follow-up period. At twelve months, the NDI had increased (worsened) by 14.7 points in the nonsurgical cohort (p < 0.0001) compared with a nonsignificant increase (worsening) of 5.7 points in the surgical group (p = 0.0555). The surgical group had significantly better outcomes as measured by the NDI and SF-36v2 Bodily Pain dimension compared with the nonsurgical group, and these differences persisted after adjustment. There was no difference in the overall rate of complications, but the surgical group had a significantly lower rate of nonunion (5% versus 21% in the nonsurgical group; p = 0.0033). Mortality was higher in the nonsurgical group compared with the surgical group (annual mortality rates of 26% and 14%, respectively; p = 0.059). We demonstrated a significant benefit with surgical treatment of dens fractures as measured by the NDI, a disease-specific functional outcome measure. As a result of the nonrandomized nature of the study, the results are vulnerable to the effects of possible residual confounding. We recommend that elderly patients with a Type-II dens fracture who are healthy enough for general anesthesia be considered for surgical stabilization to improve functional outcome as well as the union and fusion rates. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 04/2013; 95(8):729-35. DOI:10.2106/JBJS.K.01636 · 4.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: STUDY DESIGN.: Systematic review and meta-analysis. OBJECTIVE.: To determine the kinematics of the adjacent segments and global cervical spine after cervical arthroplasty compared with anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA.: Adjacent segment pathology after ACDF is a significant concern. Arthroplasty may decrease the risk of adjacent segment degeneration by maintaining normal spinal kinematics compared with fusion. However, the differences in the in vivo kinematics of the adjacent segments after cervical fusion versus arthroplasty have not been clearly established. METHODS.: A systematic literature review of studies comparing adjacent segment kinematic changes between fusion and arthroplasty was performed. We included randomized controlled trials and cohort studies that compared cervical arthroplasty with ACDF in adults with degenerative disease and reported on at least 1 outcome of interest. Meta-analysis was performed using a random-effects model where appropriate. The standardized mean difference of changes from baseline to follow-up between treatment groups was determined. Recommendations were made using Grades of Recommendation Assessment, Development, and Evaluation criteria. RESULTS.: We identified 12 studies, including 7 randomized controlled trials, 4 cohort studies, and 1 case-control study that evaluated kinematic measurements at the adjacent segments or the global cervical spine (C2-C7) after cervical arthroplasty compared with ACDF. We found no statistically significant differences between treatment groups in the change in range of motion (ROM) at the cranial or caudal adjacent segments from baseline to 2 years of follow-up. However, there was low evidence that the global cervical spine (C2-C7) had significantly greater change in ROM after arthroplasty compared with ACDF: patients had a greater angular ROM as measured up to 2 years after arthroplasty. We found no statistically significant differences between treatment groups in the change in the horizontal or vertical centers of rotation at the adjacent segments as measured up to 2 years after surgery. Regarding sagittal alignment, the cranial and caudal adjacent segments both became significantly more lordotic after arthroplasty compared with fusion at 1 to 2 years after surgery. However, there was no statistically significant difference between treatment groups in the change in global cervical sagittal alignment from baseline to 2 years. CONCLUSION.: There is no statistically or clinically significant difference in the adjacent segment ROM or centers of rotation after cervical arthroplasty compared with ACDF. However, the change in sagittal alignment at the cranial and caudal adjacent segments was significantly more lordotic after arthroplasty compared with fusion. In addition, although we found that there was no statistically significant difference between treatment groups in the change in global cervical (C2-C7) sagittal alignment, there was a significantly greater change in the angular ROM of the cervical spine at up to 2 years after arthroplasty than occurred after fusion. CONSENSUS STATEMENT: Patients can be advised that single-level arthroplasty and ACDF result in clinically similar kinematic changes at short-term follow-up.Strength of Statement: Strong.
    Spine 08/2012; 37(22 Suppl):S85-95. DOI:10.1097/BRS.0b013e31826d6628 · 2.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM. Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors. The study enrolled 302 patients (mean age 57 years, range 29-86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002-1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002-1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015-1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626-17.256, p = 0.006). For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.
    Journal of neurosurgery. Spine 02/2012; 16(5):425-32. DOI:10.3171/2012.1.SPINE11467 · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Study design: Systematic review.Clinical question: Does single-level unconstrained, semiconstrained, or fully constrained cervical artificial disc replacement (C-ADR) improve health outcomes compared with single-level anterior cervical discectomy and fusion (ACDF) in the long-term?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 US Food and Drug Administration (FDA) studies reporting long-term (≥ 48 months) follow-up results of C-ADR compared with ACDF. Non-FDA trials and FDA trials reporting outcomes at short-term or mid-term follow-up periods were excluded. Two independent reviewers assessed the strength of evidence using the GRADE criteria and disagreements were resolved by consensus.Results: Two FDA trials reporting outcomes following C-ADR (Bryan disc, Prestige disc) versus ACDF at follow-up periods of 48 months and 60 months were found (follow-up rates are 68.7% [318/463] and 50.1% [271/541], respectively). Patients in the C-ADR group showed a higher rate of overall success, greater improvements in Neck Disability Index, neck and arm pain scores, and SF-36 PhysicalComponent Scores at long-term follow-up compared with those in the ACDF group. The rate of adjacent segment disease was less in the C-ADR group versus the ACDF group at 60 months (2.9% vs 4.9%). Normal segmental motion was maintained in the C-ADR group. Furthermore, rates of revision and supplemental fixation surgical procedures were lower in the arthroplasty group.Conclusions: C-ADR is a viable treatment option for cervical herniated disc/spondylosis with radiculopathy resulting in improved clinical outcomes, maintenance of normal segmental motion, and low rates of subsequent surgical procedures at 4 to 5 years follow-up. More studies with long-term follow-up are warranted.
    02/2012; 3(S1):59-66. DOI:10.1055/s-0031-1298610
  • Ben J Garrido, Rick C Sasso
    [Show abstract] [Hide abstract]
    ABSTRACT: The evolution of occipitocervical fixation and new rigid universal screw-rod construct technology has allowed secure anchorage at each level of the occipitocervical junction with the elimination of rigid external orthoses. Rigid occipitocervical instrumentation constructs have achieved higher fusion rates and less postoperative immobilization-associated complications. Outcomes have improved compared with former nonrigid instrumentation techniques; however, with advances of rigid occipitocervical stabilization capability have come new challenges, risks, and operative techniques. A thorough understanding of the relevant cervical bony and soft tissue anatomy is essential for safe implantation and a successful outcome.
    Orthopedic Clinics of North America 01/2012; 43(1):1-9, vii. DOI:10.1016/j.ocl.2011.08.009 · 1.70 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intraoperative imaging often does not provide adequate visualization to ensure safe placement of screws. Therefore, the authors investigated the accuracy of a freehand technique for placement of pars, pedicle, and intralaminar screws in C-2. Sixteen cadaveric specimens were instrumented freehand by 2 experienced cervical spine surgeons with either a pars or pedicle screw, and bilateral intralaminar screws. The technique was based on anatomical starting points and published screw trajectories. A pedicle finder was used to establish the trajectory, followed by tapping, palpation, and screw placement. After placement of all screws (16 pars screws, 16 pedicle screws, and 32 intralaminar screws), the C-2 segments were disarticulated, radiographed in anteroposterior, lateral, and axial planes, and meticulously inspected by another spine surgeon to determine the nature and presence of any defects. A total of 64 screws were evaluated in this study. Pars screws exhibited 2 critical defects (1 in the foramen transversarium and 1 in the C2-3 facet) and an insignificant dorsal cortex breech, for an overall accuracy rate of 81.3%. Pedicle screws demonstrated only 1 insignificant violation (inferior facet/medial cortex intrusion of 1 mm) with an accuracy rate of 93.8%, and intralaminar screws demonstrated 3 insignificant violations (2 in the ventral canal, 1 in the caudad lamina breech) for an accuracy rate of 90.6%. Pars screws had significantly more critical violations than intralaminar screws (p = 0.041). Instrumentation of the C-2 vertebrae using the freehand technique for insertion of pedicle and intralaminar screws showed a high success rate with no critical violations. Pars screw insertion was not as reliable, with 2 critical violations from a total of 16 placements. The freehand technique appears to be a safe and reliable method for insertion of C-2 pedicle and intralaminar screws.
    Neurosurgical FOCUS 10/2011; 31(4):E11. DOI:10.3171/2011.6.FOCUS1167 · 2.14 Impact Factor
  • The Spine Journal 10/2011; 11(10):S1. DOI:10.1016/j.spinee.2011.08.016 · 2.80 Impact Factor
  • The Spine Journal 10/2011; 11(10):S47. DOI:10.1016/j.spinee.2011.08.123 · 2.80 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The published two-year results of the pivotal U.S. Food and Drug Administration investigational device exemption trial with the use of the Bryan cervical disc arthroplasty compared with anterior cervical discectomy with fusion for treating single-level degenerative cervical disc disease revealed a significantly superior overall success rate in the arthroplasty group. The purpose of this study was to evaluate the midterm safety and effectiveness of the Bryan disc as an alternative to arthrodesis following anterior cervical discectomy. A prospective, multicenter randomized clinical trial was undertaken for the treatment of persistent radiculopathy or myelopathy due to single-level cervical disc herniations or spondylosis. Patients were randomized to treatment with either the Bryan disc (the arthroplasty group; 242 patients) or anterior cervical discectomy and fusion (the fusion group; 221 patients). Patients completed preoperative and postoperative self-assessment forms at specified intervals and had radiographs made preoperatively, at six weeks, and at three, six, twelve, twenty-four, and forty-eight months after surgery. The primary outcome measure was overall success, a composite variable of safety and efficacy measures. Numerous secondary measures were assessed. The follow-up data for up to twenty-four months have been previously published. We report in the present study the forty-eight-month data collected on 181 patients who received the Bryan disc and 138 patients who underwent anterior cervical discectomy and fusion. The study groups were demographically similar. Substantial reduction in Neck Disability Index scores occurred in both groups compared with preoperative values. The greater improvement in the Neck Disability Index score in the Bryan disc cohort persisted through the four-year follow-up period (p < 0.001). The four-year overall success rates were 85.1% and 72.5% for the arthroplasty and fusion groups, respectively (p = 0.004). The improvement in the arm pain score was substantial for both groups and significantly greater in the Bryan disc cohort (p = 0.028), and the neck pain scores showed persistently greater improvement in the Bryan disc group at forty-eight months of follow-up (p = 0.001). Short Form-36 physical component score improvement remained greater among the Bryan disc cohort (p = 0.007). The mean range of motion for the Bryan disc was 8.08° and 8.48° at twenty-four and forty-eight months, respectively. Total and serious adverse event rates were similar between the groups. The forty-eight-month follow-up data in the present report showed consistent, sustained significantly superior outcomes for cervical spine arthroplasty compared with cervical spine fusion. The arthroplasty cohort continued to show significantly greater improvements in Neck Disability Index, neck pain score, arm pain score, and Short Form-36 physical component score, as well as the primary outcome measure, overall success, at forty-eight months following surgery.
    The Journal of Bone and Joint Surgery 09/2011; 93(18):1684-92. DOI:10.2106/JBJS.J.00476 · 4.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the routine performance of minimally invasive surgery, computer-assisted spinal navigation technologies blend anatomic information with real-time visual feedback. Over time, navigation systems have been adapted to multiple imaging modalities. These systems have been shown to be at least comparable with conventional techniques when accuracy of hardware placement, size of incision, and procedural speed are compared. Computer-assisted spinal navigation can be an invaluable tool when paired with complex revision anatomy or in situations where traditional direct visualization of anatomy is impaired. Modern spinal navigation systems are available from most of the major medical device manufacturers, and are being adopted in many tertiary care centers and spine specialty practices. Herein, we discuss the basics of spinal navigation technology as they relate to minimally invasive surgery and review the literature regarding navigation efficacy.
    Techniques in Orthopaedics 08/2011; 26(3):194–201. DOI:10.1097/BTO.0b013e3182308ed5
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ossification of the anterior longitudinal ligament and the anulus adjacent to an anterior cervical arthrodesis has been termed adjacent-level ossification development. Initial studies suggested an association with the placement of plates <5 mm from an adjacent disc space. A follow-up study demonstrated that this ossification rarely occurs in association with arthrodeses without plate fixation. In the present study, our goal was to determine the incidence of adjacent-level ossification in patients who underwent cervical arthrodesis with plate fixation as compared with that in patients who underwent cervical arthroplasty. We performed a post hoc analysis of prospectively collected data. Radiographic data for all patients from a single site were used. All postoperative, two-year, and four-year follow-up lateral cervical spine radiographs were collected and formatted to occlude the surgical level, blinding the readers as to the procedure performed. Three independent blinded surgeons graded the cephalad adjacent level for the degree of ossification at each time point. The data were statistically analyzed for significant ossification grade differences between arthrodesis and arthroplasty. A total of forty-six patients (twenty-one with a Bryan total disc arthroplasty and twenty-five with an arthrodesis) were included. Both cohorts were derived from previous participation in a Level-I multicenter prospective randomized controlled trial stratified by site. Ossification scores based on independent assessment by three readers at multiple follow-up times were used. The arthrodesis group had significantly higher ossification scores than the arthroplasty group at both the two-year (p = 0.003) and the four-year follow-up interval (p = 0.004). Both cohorts showed significant increases in ossification from the two-year follow-up to the latest follow-up (p = 0.001 for the anterior cervical arthrodesis group and p = 0.008 for the arthroplasty group). Our data conclusively demonstrate that cervical intervertebral arthroplasty is associated with a significantly lower incidence of adjacent-level ossification than arthrodesis with plate fixation at both the two-year and the four-year follow-up. Arthroplasty has the advantage of not being associated with adjacent-level ossification, which may decrease cervical spine motion above and below the surgical level.
    The Journal of Bone and Joint Surgery 07/2011; 93(13):1185-9. DOI:10.2106/JBJS.J.00029 · 4.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cervical arthroplasty offers theoretical advantages over traditional spinal fusion, including elimination of adjacent segment disease and elimination of the risk of pseudoarthrosis formation. Initial studies of cervical arthroplasty have shown promising results, however, the ideal design characteristics for disc replacement constructs have not been determined. The current study seeks to quantify the differences in the shock absorption characteristics of three commonly used materials in cervical disc arthroplasty. Three different nucleus materials, polyurethane (PU), polyethylene (PE) and a titanium-alloy (Ti) were tested in a humidity- and temperature-controlled chamber. Ten of each nucleus type underwent three separate mechanical testing protocols to measure 1) dynamic stiffness, 2) quasi-static stiffness, 3) energy absorption, and 4) energy dissipation. The results were compared using analysis of variance. PU had the lowest mean dynamic stiffness (435 ± 13 N/mm, P < .0001) and highest energy absorption (19.4 ± 0.1 N/mm, P < .0001) of all three nucleus materials tested. PU was found to have significantly higher energy dissipation (viscous damping ratio 0.017 ± 0,001, P < .0001) than the PE or TI nuclei. PU had the lowest quasi-static stiffness (598 ± 23 N/mm, P < .0001) of the nucleus materials tested. A biphasic response curve was observed for all of the PU nuclei tests. Polyurethane absorbs and dissipates more energy and is less stiff than either polyethylene or titanium. Basic Science/Biomechanical Study. This study characterizes important differences in biomechanical properties of materials that are currently being used for different cervical disc prostheses.
    SAS Journal 06/2011; 5(2):48-54. DOI:10.1016/j.esas.2011.01.002

Publication Stats

2k Citations
199.97 Total Impact Points


  • 2013
    • Toronto Western Hospital
      Toronto, Ontario, Canada
  • 2012
    • University of California, San Francisco
      • Department of Neurological Surgery
      San Francisco, CA, United States
  • 2003–2012
    • Indiana University-Purdue University School of Medicine
      • Orthopaedic Surgery
      Indianapolis, Indiana, United States
  • 2005–2011
    • Indiana University-Purdue University Indianapolis
      • Department of Orthopaedic Surgery
      Indianapolis, Indiana, United States
  • 2009
    • Harvard Medical School
      • Department of Orthopaedic Surgery
      Boston, Massachusetts, United States
  • 2007–2009
    • Indianapolis Zoo
      Indianapolis, Indiana, United States
  • 2006–2009
    • University of Wisconsin, Madison
      • • Department of Orthopedics and Rehabilitation
      • • Department of Neurological Surgery
      Madison, MS, United States
  • 2004–2009
    • Rothman Institute
      Philadelphia, Pennsylvania, United States
  • 2008
    • St. Vincent Hospital
      Green Bay, Wisconsin, United States
  • 2007–2008
    • Walter Reed National Military Medical Center
      • Department of Orthopaedics and Rehabilitation
      Washington, Washington, D.C., United States
  • 2006–2008
    • Thomas Jefferson University
      • Department of Orthopaedic Surgery
      Philadelphia, Pennsylvania, United States
  • 2003–2005
    • Emory University
      • Department of Neurosurgery
      Atlanta, GA, United States