Five-year Follow-up of a Prospective Food and Drug Administration Investigational Device Exemption Trial Evaluating a PEEK-on-Ceramic Cervical Disc Replacement.

STUDY DESIGN: Prospective trial comparing the investigation group to propensity matched historic control group. OBJECTIVE: To evaluate 5-year results of single-level PEEK-on-ceramic cervical total disc replacement (TDR) compared to a propensity matched anterior cervical discectomy and fusion (ACDF) control group. SUMMARY OF BACKGROUND DATA: Cervical TDR has gained acceptance as treatment for symptomatic disc degeneration. The design and materials used in these devices continue to evolve. METHODS: Data were collected in the Food and Drug Administration Investigational Device Exemption trial for the PEEK-on-ceramic Simplify(®) Cervical Artificial Disc (n=150) with comparison to a propensity matched ACDF control group (n=117). All patients were treated for single-level cervical disc degeneration with radiculopathy and/or myelopathy. Clinical outcome was based on composite clinical success (CCS), Neck Disability Index (NDI), visual analog scales (VAS) assessing pain, re-operations, and satisfaction. Radiographic measures included segmental range of motion (ROM), disc space height, and heterotopic ossification (HO). Evaluations were performed pre-operatively and post-operatively within 2 and 6 weeks, and 3, 6, 12 months, and annually thereafter. RESULTS: At 5-year follow-up, CCS was significantly greater with TDR than ACDF (91.1% vs. 74.6%; P<0.01). In the TDR group, the mean NDI score was 63.3 pre-operatively, reduced significantly to 23.1 at 6 weeks and remained below 20 throughout 5-year follow-up. In the ACDF group, the mean pre-operative NDI score was 62.4, decreasing to 33.7 at 6 weeks, and ranged from 25.9 to 21.5 throughout follow-up. Mean NDI scores were significantly lower in TDR group at all post-operative points (P<0.05). Mean TDR ROM was 7.3o pre-operatively and 10.1o at 5 years. Bridging HO occurred in 9%. With TDR, there were 6 re-operations (4.0%) vs. 11 (9.4%) with ACDF (P>0.40). CONCLUSION: PEEK-on-ceramic TDR produced significantly improved outcomes maintained throughout 5-year follow-up, were similar or superior to ACDF, supporting TDR in appropriately selected patients.

A Subdural Dissection of Cerebrospinal Fluid Causing Cauda Equina Centralization After Durotomy: A Case Report.

CASE: A 61-year-old woman with recurrent left L5 radiculopathy underwent revision L4-5 decompression complicated by incidental durotomy requiring primary repair. Postoperative course was complicated by wound drainage and headache. Repeat magnetic resonance imaging demonstrated cerebrospinal fluid dissecting a plane deep to the dura mater but superficial to the arachnoid, with the collection compressing the cauda equina in an atypical horizontal and linear fashion. Nonoperative treatment was ineffective, and she required revision decompression and dural repair. CONCLUSION: Spine surgeons should recognize this finding on postoperative imaging as a potential sign of an incomplete dural repair necessitating return to the operating room.

20-year Clinical Outcomes of Cervical Disk Arthroplasty: A Prospective, Randomized, Controlled Trial.

STUDY DESIGN: Prospective, randomized, controlled trial. OBJECTIVE: To compare clinical outcomes of anterior cervical discectomy and fusion (ACDF) and cervical disk arthroplasty (CDA) at 20 years. SUMMARY OF BACKGROUND DATA: Concern for adjacent-level disease after ACDF prompted the development of CDA. MATERIALS AND METHODS: Forty-seven patients with single-level cervical radiculopathy were randomized to either BRYAN CDA or ACDF for a Food and Drug Administration Investigational Device Exemption trial. At 20 years, patient-reported outcomes, including visual analog scales (VAS) for neck and arm pain, neck disability index (NDI), and reoperation rates, were analyzed. RESULTS: Follow-up rate was 91.3%. Both groups showed significantly better NDI, VAS arm pain, and VAS neck pain scores at 20 years versus preoperative scores. Comparing CDA versus ACDF, there was no difference at 20 years in mean scores for NDI [11.1 (SD 14.1) vs. 19.9 (SD 17.2), P =0.087], mean VAS arm pain [0.9 (SD 2.4) vs. 2.3 (SD 2.8), P =0.095], or mean VAS neck pain [1.2 (SD 2.5) vs. 2.9 (3.3), P =0.073]. There was a significant difference between CDA versus ACDF groups in the change in VAS neck pain score between 10 and 20 years [respectively, -0.4 (SD 2.5) vs. 1.5 (SD 2.5), P =0.030]. Reoperations were reported in 41.7% of ACDF patients and 10.0% of CDA patients ( P =0.039). CONCLUSIONS: Both CDA and ACDF are effective in treating cervical radiculopathy with sustained improvement in NDI, VAS neck and VAS arm pain at 20 years. CDA demonstrates lower reoperation rates than ACDF. There were no failures of the arthroplasty device requiring reoperation at the index level. The symptomatic nonunion rate of ACDF was 4.2% at 20 years. Despite a higher reoperation rate in the CDA group versus ACDF group, there was no difference in the 20-year NDI, VAS Neck, and VAS arm pain scores.