Anterior and Lateral Lumbar Interbody Fusion With Supplemental Interspinous Process Fixation: Outcomes from a Multicenter, Prospective, Randomized, Controlled Study.

BACKGROUND: Rigid interspinous process fixation (ISPF) has received consideration as an efficient, minimally disruptive technique in supporting lumbar interbody fusion. However, despite advantageous intraoperative utility, limited evidence exists characterizing midterm to long-term clinical outcomes with ISPF. The objective of this multicenter study was to prospectively assess patients receiving single-level anterior (ALIF) or lateral (LLIF) lumbar interbody fusion with adjunctive ISPF. METHODS: This was a prospective, randomized, multicenter (11 investigators), noninferiority trial. All patients received single-level ALIF or LLIF with supplemental ISPF (n = 66) or pedicle screw fixation (PSF; n = 37) for degenerative disc disease and/or spondylolisthesis (grade ≤2). The randomization patient ratio was 2:1, ISPF/PSF. Perioperative and follow-up outcomes were collected (6 weeks, 3 months, 6 months, and 12 months). RESULTS: For ISPF patients, mean posterior intraoperative outcomes were: blood loss, 70.9 mL; operating time, 52.2 minutes; incision length, 5.5 cm; and fluoroscopic imaging time, 10.4 seconds. Statistically significant improvement in patient Oswestry Disability Index scores were achieved by just 6 weeks after operation (P < .01) and improved out to 12 months for the ISPF cohort. Patient-reported 36-Item Short Form Health Survey and Zurich Claudication Questionnaire scores were also significantly improved from baseline to 12 months in the ISPF cohort (P < .01). A total of 92.7% of ISPF patients exhibited interspinous fusion at 12 months. One ISPF patient (1.5%) required a secondary surgical intervention of possible relation to the posterior instrumentation/procedure. CONCLUSION: ISPF can be achieved quickly, with minimal tissue disruption and complication. In supplementing ALIF and LLIF, ISPF supported significant improvement in early postoperative (≤12 months) patient-reported outcomes, while facilitating robust posterior fusion.

Systemic Hypothermia as Treatment for an Acute Cervical Spinal Cord Injury in a Professional Football Player: 9-Year Follow-Up.

The following report provides clinical follow-up on a National Football League player who sustained a complete cervical spinal cord injury (SCI) while tackling an opposing player in 2007. He received prompt medical and surgical care based on then-current recommendations, but was also treated with systemic hypothermia soon after his injury, which was controversial at the time. Since then, smaller randomized human studies have described the tolerable safety profile, efficacy, and potential benefits of this intervention in acute SCI in humans. Now, modest systemic hypothermia can be one of many tools considered in the treatment of acute SCI. Before it can become the standard of care, however, additional larger prospective randomized studies need to be completed. The patient described in this article had long-term excellent clinical results, with residual deficits of occasional tingling in fingertips and toe tips, although the patient continues to slowly improve.

A prospective, randomized, controlled clinical investigation comparing PCM cervical disc arthroplasty with anterior cervical discectomy and fusion. 2-year results from the US FDA IDE clinical trial.

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.

Systemic hypothermia for the treatment of acute cervical spinal cord injury in sports.

Spinal cord injury is a devastating condition that affects approximately 12,000 patients each year in the United States. Major causes for spinal cord injury include motor vehicle accidents, sports-related injuries, and direct trauma. Moderate hypothermia has gained attention as a potential therapy due to recent experimental and clinical studies and the use of modest systemic hypothermia (MSH) in high profile case of spinal cord injury in a National Football League (NFL) player. In experimental models of spinal cord injury, moderate hypothermia has been shown to improve functional recovery and reduce overall structural damage. In a recent Phase I clinical trial, systemic hypothermia has been shown to be safe and provide some encouraging results in terms of functional recovery. This review will summarize recent preclinical data, as well as clinical findings that support the continued investigations for the use of hypothermia in severe cervical spinal cord injury.

Biomechanical analysis and review of lateral lumbar fusion constructs.

STUDY DESIGN: Biomechanical study and the review of literature on lumbar interbody fusion constructs. OBJECTIVE: To demonstrate the comparative stabilizing effects of lateral interbody fusion with various supplemental internal fixation options. SUMMARY OF BACKGROUND DATA: Lumbar interbody fusion procedures are regularly performed using anterior, posterior, and more recently, lateral approaches. The biomechanical profile of each is determined by the extent of resection of local supportive structures, implant size and orientation, and the type of supplemental internal fixation used. METHODS: Pure moment flexibility testing was performed using a custom-built 6 degree-of-freedom system to apply a moment of ±7.5 Nm in each motion plane, while motion segment kinematics were evaluated using an optoelectronic motion system. Constructs tested included the intact spine, stand-alone extreme lateral interbody implant, interbody implant with lateral plate, unilateral and bilateral pedicle screw fixation. These results were evaluated against those from literature-reported biomechanical studies of other lumbar interbody constructs. RESULTS: All conditions demonstrated a statistically significant reduction in range of motion (ROM) as a percentage of intact. In flexion-extension, ROM was 31.6% stand-alone, 32.5% lateral fixation, and 20.4% and 13.0% unilateral and bilateral pedicle screw fixation, respectively. In lateral bending, the trend was similar with greater reduction with lateral fixation than in flexion-extension; ROM was 32.5% stand-alone, 15.9% lateral fixation, and 21.6% and 14.4% unilateral and bilateral pedicle screw fixation. ROM was greatest in axial rotation; 69.4% stand-alone, 53.4% lateral fixation, and 51.3% and 41.7% unilateral and bilateral pedicle screw fixation, respectively. CONCLUSION: The extreme lateral interbody construct provided the largest stand-alone reduction in ROM compared with literature-reported ALIF and TLIF constructs. Supplemental bilateral pedicle screw-based fixation provided the overall greatest reduction in ROM, similar among all interbody approach techniques. Lateral fixation and unilateral pedicle screw fixation provided intermediate reductions in ROM. Clinically, surgeons may evaluate these comparative results to choose fixation options commensurate with the stability requirements of individual patients.

The use of systemic hypothermia for the treatment of an acute cervical spinal cord injury in a professional football player.

STUDY DESIGN: Case Report. OBJECTIVE: We will describe the injury and clinical course of an NFL Football player who sustained a complete spinal cord injury and was treated with conventional care in addition to modest systemic hypothermia. SUMMARY OF BACKGROUND DATA: Systemically induced moderate hypothermia is a potentially neuroprotective intervention in acute spinal cord injury. However, case descriptions of human patients receiving systemic hypothermia after spinal cord injuries are lacking in the literature. METHODS: Here, we present the case of a National Football League player who sustained a complete (ASIA A) spinal cord injury from a C3/4 fracture dislocation. Moderate systemic hypothermia was instituted immediately after his injury, in addition to standard medical/surgical treatment, including, surgical decompression and intravenous methylprednisolone. RESULTS: The patient experienced significant and rapid neurologic improvement, and within weeks of his injury was walking with harness assistance. Since that time, the patient has continued to make significant progress in his rehabilitation (now ASIA D). CONCLUSION: The extent to which this hypothermia contributed to his neurologic recovery is difficult to determine. It is hoped that this case will draw attention to the need for further preclinical and clinical studies to elucidate the role of hypothermia in acute spinal cord injury. Until these studies are completed, it is impossible to advocate for systemic hypothermia as a standard of care.

Lower incidence of dysphagia with cervical arthroplasty compared with ACDF in a prospective randomized clinical trial.

STUDY DESIGN: The current study of 251 consecutive 1-level anterior cervical reconstructions was undertaken to compare the incidence of dysphagia between cervical disk replacement and conventional anterior cervical fusion and instrumentation. OBJECTIVES: This is a report of 251 patients from 5 investigational centers in the Food and drug Administration's prospective, randomized porous-coated motion (PCM) trial using a validated dysphagia outcomes instrument. The dysphagia data for both PCM and anterior cervical diskectomy and fusion (ACDF) patients were reviewed from 5 centers to (1) compare the severity of dysphagia, (2) compare the postoperative incidence of dysphagia, and (3) to compare the resolution of perioperative dysphagia. SUMMARY OF BACKGROUND DATA: Dysphagia and dysphonia after anterior surgical approaches to the cervical spine have been previously reported. The current prospective, randomized investigation quantifies clinical dysphagia based on 3 criteria-severity, incidence, and resolution-in a time-course evaluation. METHODS: Patients between 18 and 65 years with 1-level symptomatic cervical radiculopathy and/or myelopathy for progressive neurologic symptoms, were randomized to undergo anterior decompression and PCM arthroplasty (N=151) or ACDF (control) (N=100). Patients self-reported dysphagia severity using the Bazaz scale preoperatively and at follow-up. The Bazaz scale has 4 classes of severity based upon the problems with swallowing that the patient has with both liquids and solids. RESULTS: The Bazaz results demonstrate that although both the PCM and ACDF groups exhibited an initial postoperative problem with swallowing, the PCM group continued to improve with increasing time after implantation, whereas the ACDF only improved minimally. The PCM treatments indicated significantly lower incidence of dysphagia at 3 and 12 months postoperatively compared with ACDF controls (P<0.05). An increase in dysphagia severity at either the 6-week or 3-month follow-up visit was reported in 35 (42%) PCM and 29 (64%) ACDF subjects. Long-term resolution of these symptoms was noted in 74% (26/35) of the PCM subjects as compared with 41.4% (12/29) of the ACDF subjects (P=0.015). CONCLUSIONS: In a prospective randomized clinical study the incidence of postoperative dysphagia and the long-term resolution of the dysphagia was greatly improved in the PCM group compared with the instrumented ACDF control group.

Cervical disc replacement in patients with and without previous adjacent level fusion surgery: a prospective study.

STUDY DESIGN: Prospective 6-center study. OBJECTIVE.: To evaluate outcomes of cervical disc replacement performed adjacent to a prior cervical fusion. SUMMARY OF BACKGROUND DATA: The use of disc replacement adjacent to a prior anterior cervical decompression and fusion (ACDF) is an attractive reconstructive option, obviating the need for a multilevel fusion. This study reports outcomes from patients with and without previous ACDF receiving the porous coated motion (PCM) artificial cervical disc in a United States Federal Drug Administration Investigational Device Exemption trials. METHODS: Patients between ages of 18 and 65 with single-level cervical radiculopathy and/or myelopathy, unresponsive to at least 6 weeks of nonsurgical therapy, or experiencing progressive neurologic symptoms were enrolled. Clinical outcomes are compared for patients receiving a PCM disc at a level adjacent to a prior ACDF ("adjacent") and those without having previously had fusion ("primary"). RESULTS: 126 PCM patients were primary (mean age: 44.4 years.) and 26 patients had previous "adjacent level" fusion surgery (mean age: 46.4 years). Surgery time was similar in both groups (96 minutes and 98 minutes, respectively; P = 0.761), and mean blood loss was 76 mL and 66 mL in the 2 groups, respectively (P = 0.491). Clinical outcomes using Neck Disability Index and Visual Analog Scores neck and arm scores showed significant improvement after surgery and were similar between groups at all time points. Revision surgery occurred in 2 of 126 primary patients, and in 2 of 26 patients in the adjacent-to-fusion group. CONCLUSION: Although the level adjacent to a prior cervical fusion is subject to increased biomechanical forces, potentially leading to a higher risk of failure, the PCM disc was well tolerated in the short term. The early clinical results of disc replacement adjacent to a prior fusion are good and comparable to the outcomes after primary disc replacement surgery. However, in view of the small study population and short-term follow-up, continued study is mandatory.

Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: five-year follow-up.

BACKGROUND CONTEXT: The CHARITE artificial disc, a lumbar spinal arthroplasty device, was approved by the United States Food and Drug Administration in 2004 based on two-year safety and effectiveness data from a multicenter, prospective, randomized investigational device exemption (IDE) study. No long-term, randomized, prospective study on the CHARITE disc or any other artificial disc has been published to date. PURPOSE: The purpose of this study was to compare the safety and effectiveness at the five-year follow-up time point of lumbar total disc replacement using the CHARITE artificial disc (DePuy Spine, Raynham, MA) with that of anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest autograft, for the treatment of single-level degenerative disc disease from L4 to S1, unresponsive to nonoperative treatment. STUDY DESIGN/SETTING: Randomized controlled trial-five-year follow-up. PATIENT SAMPLE: Ninety CHARITE patients and 43 BAK patients. OUTCOME MEASURES: Self-reported measures: visual analog scale (VAS); validated Oswestry disability index (ODI version 1.0); Short-Form 36 Questionnaire, and patient satisfaction. Physiologic measures: radiographic range of motion, disc height, and segmental translation. Functional measures: work status. METHODS: Of the 375 subjects enrolled in the CHARITE IDE trial, 277 were eligible for the five-year study and 160 patients thereof completed the five-year follow-up. The completers included 133 randomized patients. Overall success was defined as improvement> or =15 pts in ODI vs. baseline, no device failure, absence of major complications, and maintenance or improvement of neurological status. Additional clinical outcomes included an ODI questionnaire as well as VAS, SF-36, and patient satisfaction surveys. Work status was tracked for all patients. Safety assessments included occurrence and severity of adverse events and device failures. Radiographic analyses such as index- and adjacent-level range of motion, segmental translation, disc height, and longitudinal ossification were also carried out. RESULTS: Overall success was 57.8% in the CHARITE group vs. 51.2% in the BAK group (Blackwelder's test: p=0.0359, Delta=0.10). In addition, mean changes from baseline for ODI (CHARITE: -24.0 pts vs. BAK: -27.5 pts), VAS pain scores (CHARITE: -38.7 vs. BAK: -40.0), and SF-36 questionnaires (SF-36 Physical Component Scores [PCS]: CHARITE: 12.6 pts vs. BAK: 12.3 pts) were similar across groups. In patient satisfaction surveys, 78% of CHARITE patients were satisfied vs. 72% of BAK patients. A total of 65.6% patients in the CHARITE group vs. 46.5% patients in the BAK group were employed full-time. This difference was statistically significant (p=0.0403). Long-term disability was recorded for 8.0% of CHARITE patients and 20.9% of BAK patients, a difference that was also statistically significant (p=0.0441). Additional index-level surgery was performed in 7.7% of CHARITE patients and 16.3% of BAK patients. Radiographic findings included operative and adjacent-level range of motion (ROM), intervertebral disc height and segmental translation. At the five-year follow-up, the mean ROM at the index level was 6.0 degrees for CHARITE patients and 1.0 degrees for BAK patients. Changes in disc height were also similar for both CHARITE and BAK patients (0.7 mm for both groups, p=0.9827). Segmental translation was 0.4 and 0.8mm in patients implanted with CHARITE at L4-L5 vs. L5-S1, respectively, and 0.1mm in BAK patients. CONCLUSIONS: The results of this five-year, prospective, randomized multicenter study are consistent with the two-year reports of noninferiority of CHARITE artificial disc vs. ALIF with BAK and iliac crest autograft. No statistical differences were found in clinical outcomes between groups. In addition, CHARITE patients reached a statistically greater rate of part- and full-time employment and a statistically lower rate of long-term disability, compared with BAK patients. Radiographically, the ROMs at index- and adjacent levels were not statistically different from those observed at two-years postsurgery.

Effect of previous surgery on clinical outcome following 1-level lumbar arthroplasty.

OBJECT: A secondary lumbar surgery at a previously surgically treated level is believed to result in minimal clinical improvement. The clinical results of the CHARITE Investigational Device Exemption (IDE) study were analyzed to assess the effect of previous surgery on clinical outcomes following either total disc replacement with the CHARITE device or anterior lumbar interbody fusion with a BAK cage and iliac crest autograft. METHODS: Patients with prior microdiscectomy, laminectomy, or minimal medial facetectomy were not excluded from enrollment in the CHARITE IDE study. Thus, the following 3 groups were analyzed: all patients treated with the CHARITE Artificial Disc, whether randomized or nonrandomized; only patients treated with CHARITE devices randomized against patients with BAK devices; and control patients with BAK devices. Each group was further subdivided based on the patients' medical history, whether they had undergone prior surgery (prior surgery group) or had not (no prior surgery group). For all groups, baseline demographics were collected and compared for any potential recruitment bias. Postoperative improvements based on Oswestry Disability Index (ODI), visual analog scale (VAS), and patient satisfaction scores were further collected and statistically analyzed. RESULTS: For all 3 groups, there were no statistical differences in clinical improvement from 3 months to 2 years postoperatively as measured using ODI and VAS scores between the subgroups (those who had prior surgery and those who did not). CONCLUSIONS: Patients indicated for 1-level lumbar arthroplasty with previous lumbar decompressive surgery can be expected to have similar clinical outcomes to patients undergoing arthroplasty without prior lumbar decompressive surgery. Similarly, candidates for anterior lumbar fusion with prior decompressive surgery may experience similar benefits from the surgical procedure as those without.

Patient selection for lumbar arthroplasty and arthrodesis: the effect of revision surgery in a controlled, multicenter, randomized study.

OBJECT: Patient selection is perhaps the most important factor in successful lumbar surgery. In this study, the authors analyzed the clinical outcomes of patients enrolled in the CHARITE investigational device exemption (IDE) trial who underwent revision surgery after primary total disc replacement with CHARITE or an anterior lumbar interbody fusion (ALIF) with placement of a BAK cage and iliac crest autograft. This revision surgery was either a supplemental posterior lumbar fixation or a 360 degrees fusion. Statistical analysis was conducted to compare clinical success in patients who underwent revision surgery with those who did not. METHODS: The patients enrolled in the CHARITE IDE study were divided into 6 groups according to treatment and repeated operation status, and their Oswestry Disability Index (ODI) and visual analog scale (VAS) scores at the 2-year follow-up and at baseline were compared. The patients had received the following treatments by group: A) ALIF without reoperation; B) ALIF with conversion to 360 degrees fusion; C) arthroplasty (randomized) without repeated operation; D) arthroplasty with supplemental posterior lumbar fixation; E) arthroplasty (nonrandomized) without repeated operation; and F) arthroplasty (nonrandomized) with supplemental posterior lumbar fixation. Outcome scores in the groups of patients who required revision surgeries (Groups B, D, and F; 23 patients) were compared with the groups that did not require revision surgery (Groups A, C, and E; 299 patients). RESULTS: Patients who required revision surgery had a significantly lower level of clinical improvement than those who did not. The mean change in ODI score was -53.0% in Groups A, C, and E, but just -12.7% in Groups B, D, and F (p < 0.0001). The mean change in VAS score was -59.1% in Groups A, C, and E, compared to -23.4% in Groups B, D, and F (p < 0.0001). No significant differences were identified in analyzing absolute change in scores and the percentage change. A comparison of outcomes in patients who had undergone arthroplasty without reoperation (Groups C and E) with all patients who had undergone revision surgery (Groups B, D, and F) demonstrated similar results (p < 0.0001). CONCLUSIONS: The 7.1% of patients who underwent a secondary stabilization procedure had poor clinical improvement. This finding may indicate that if the alternative treatment had been the initial treatment, these patients would not have benefited, and further implies a 7.1% rate of imprecision in preoperative evaluation.

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITE artificial disc compared with fusion.

OBJECT: One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations. METHODS: Radiographs of patients enrolled in the CHARITE investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations. RESULTS: Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4-5 level was as follows: 28% motion was observed at L3-4, 35% at L4-5 and 37% at L5-S1. Following a one-level arthroplasty at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3-4, 30% at L4-5 and 35% at L5-S1. Following a one-level fusion with BAK and pedicle screws at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3-4, 9% at L4-5 and 46% at L5-S1. CONCLUSIONS: The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.

Porous coated motion cervical disc replacement: a biomechanical, histomorphometric, and biologic wear analysis in a caprine model.

STUDY DESIGN: The biomechanical, histopathologic, and histomorphometric characteristics of cervical disc replacement were assessed in a caprine animal model. OBJECTIVE: To investigate the biomechanical, porous ingrowth, and histopathologic characteristics of the Porous Coated Motion (PCM) Cervical Disc replacement (Cervitech, Inc., Rockaway, NJ). SUMMARY OF BACKGROUND DATA: As an alternative to anterior cervical interbody arthrodesis, an artificial cervical disc serves to replace the symptomatic degenerated disc, restore the functional biomechanical properties of the motion segment, and preserve neurologic function. METHODS: There were 12 mature Nubian goats divided into 2 groups based on postoperative survival periods of 6 (n = 6) and 12 months (n = 6). Using an anterior surgical approach, a complete discectomy was performed at the C3-C4, followed by implantation of the PCM device. Functional outcomes of the disc prosthesis were based on computerized tomography (CT), multidirectional flexibility testing, undecalcified histology, histomorphometric, and immunocytochemical analyses. RESULTS: There was no evidence of prosthesis loosening, or neurologic or vascular complications. CT showed the ability to image and assess the cervical spinal canal for the presence of compressive pathology in the area of the CoCrMo prosthesis. Multidirectional flexibility testing under axial rotation and lateral bending indicated no differences in the full range of intervertebral motion between the disc prosthesis and nonoperative controls (P > 0.05). Based on immunohistochemical and histologic analysis, there was no evidence of particulate debris, cytokines, or cellular apoptosis within the local or systemic tissues. Moreover, review of the spinal cord at the operative levels indicated no evidence of cord lesions, inflammatory reaction, wear particles, or significant pathologic changes in any treatment. Histomorphometric analysis at the metal-bone interface indicated the mean trabecular ingrowth of 40.5% +/- 24.4% and 58.65% +/- 28.04% for the 6 and 12-month treatments, respectively. CONCLUSION: To our knowledge, this serves as the first in vivo time-course study investigating the use of the PCM device for cervical arthroplasty. All 12 animals undergoing cervical disc replacement had no evidence of implant loosening, subluxation, or inflammatory reactions. PCM cervical arthroplasty permits unobstructed visualization of the spinal canal based on CT imaging. Segmental intervertebral motion was preserved under axial rotation and lateral bending loading conditions, while at the same time permitting porous osseointegration at the prosthesis-bone interface. Based on histopathologic review of all local and systemic tissues, there was no evidence of particulate wear debris, cytokines, cellular apoptosis, or significant pathologic changes in any treatment.

Anterior cervical discectomy and fusion with implantable titanium cage: initial impressions, patient outcomes and comparison to fusion with allograft.

BACKGROUND CONTEXT: The use of metal cage prosthetic devices in anterior cervical discectomy with fusion (ACDF) has increased rapidly. One of these devices is the titanium Rabea cage (Signus, Alzenau, Germany) [correction]. There are no peer-reviewed objective reports on the use of these cages in cervical discectomy. PURPOSE: The authors present preliminary outcomes data on the Rabea cage. This study is intended to provide adjunct data for surgeons who are using or are considering the use of these devices. STUDY DESIGN/SETTING: Patients in a private practice were studied prospectively as part of a long-term assessment of outcomes using several surgical procedures. Data were collated and analyzed by an independent researcher. PATIENT SAMPLE: Rabea cages were used in consecutive candidates (n=37) for ACDF. The results using Rabea cages were compared with two prospectively studied control groups, one historical (n=66) and one concurrent (n=28), both groups using ACDF with bone allograft and no instrumentation. OUTCOME MEASURES: Success at 6 months after surgery was determined using six major patient-reported outcome measures, including visual analog scales (VAS) for arm and neck pain, the Oswestry pain and disability scale, four-part (excellent-through-poor) scales for measurement of return to activities of daily living or to work and satisfaction with the results of surgery. Perioperative complications, number of vertebral levels fused, and worker's compensation and smoking status were also compared among the study groups. Fusion and subsidence were evaluated for the Rabea cage group. METHODS: Criteria for inclusion consisted of consecutive patients who presented with unremitting radicular arm pain, with or without neck pain, and/or a neurological deficit that correlated with appropriate level and side neural compression on magnetic resonance imaging or computed tomography. Questionnaire follow-up was at 6 months after surgery with 100% compliance. RESULTS: A total of 50 cages were implanted in the 37 patients. At 6-month follow-up, 78% of patients reported successful arm pain relief (VAS scores below 5). Patient satisfaction was successful in 78% of the cases. Other success rates included neck pain relief in 73% and Oswestry pain and disability scale in 70%. There was a median improvement in the Oswestry scores of 28 points (61% change). Worker's compensation patients fared dramatically worse than did the noncompensation patients in all outcome measurements. Combining all three study groups resulted in significantly worse outcomes for multilevel than for single-level procedures and for smokers compared with nonsmokers, but low case numbers precluded conclusive analysis for the Rabea group alone. In the Rabea group there were two complications, neither cage related, whereas none were reported for the ACDF controls. Rabea group fusion rates were 84% at 3 months and 95% at 6 months, but the clinical relevance of this radiological evidence when metal prostheses are used is questionable. The outcomes results were clinically and statistically indistinguishable from those of our control groups and were similar to published studies using other titanium cages. CONCLUSIONS: This is the first prospective, independently conducted report on Rabea cages. Results of the short-term (6 months) follow-up did not differ from outcomes results in our patients who have undergone ACDF with bone allograft. Although this is a preliminary assessment, the Rabea cage may represent an alternative to bone dowels and hip graft. As is the case for other allografts, artificial or bone, the main advantage is elimination of donor site complications, and the disadvantages include difficulty in radiographic assessment of fusion and potential for cage subsidence.