Five-Year Follow-Up of a Prospective, Randomized FDA IDE Trial Comparing Two Lumbar Total Disc Replacements: Clinical Outcome and Serum Ion Level Analysis for a Metal-on-Metal Device (original) (raw)

BACKGROUND CONTEXT: Recently, results have been reported following the use of several cervical disc arthroplasty devices as an alternative to fusion after anterior cervical discectomy in the treatment of symptomatic cervical spondylosis. The PCM Cervical DiscÒ is a newly FDA-approved non-constrained device. PURPOSE: This is the first presentation of long-term (5-year) results from the US FDA IDE clinical trial of the PCM Cervical Disc versus anterior cervical discectomy and fusion (ACDF) with allograft and plate. STUDY DESIGN/SETTING: Prospective, randomized, multicenter, IRBapproved IDE clinical trial evaluating longitudinal outcomes over 5 years comparatively between arthroplasty and fusion groups. PATIENT SAMPLE: Patients 18-65 years of age with degenerative disc disease at one level between C3 and T1 with neurologic symptoms unresponsive to conservative care were included. A total of 404 patients were treated (214 PCM, 190 ACDF). The patient sample at 5 years included 160 patient in the PCM group and 124 in the ACDF group. OUTCOME MEASURES: Outcomes measures included neck disability index (NDI), neurological success (a motor, sensory, reflex composite), overall success (composite primary endpoint), flexion-extension range of motion (ROM), and rate of secondary surgeries at the operative level (revisions, reoperations, removals, and supplemental fixation). METHODS: NDI success defined as a minimum 20% improvement over baseline. Neurological success defined as maintenance or improvement in neurological status over baseline. Where appropriate, measures were tested for significant change from baseline to the 5-year postoperative follow-up visit, as well as differences between arthroplasty and fusion groups. RESULTS: At 5 years, the mean NDI score was 20.4 in the PCM group compared to 28.5 in the ACDF group (p50.001). Mean reduction in NDI score from baseline was 34.4 in the PCM group compared to 26.8 in the ACD group (p50.003). NDI success was achieved in 84.7% (133/ 157) of the PCM patients compared to 73.6% (92/125) in the ACDF patients (p50.025). Neurological success was achieved in 92.1% (140/152) of the PCM group and 88.2% (105/119) of the ACDF group (p50.305). ROM at the index level averaged 5.3 (range 0-16.1) for the PCM group and 0.5 (range 0-4.1) for the controls. In both groups, adjacent level ROM was generally consistent with the 2-, 3-and 4-year results. Overall success was achieved in 66.9% (107/160) of the PCM patients and 57.3% (71/124) of the ACDF patients (p50.108). Of the treated patients, secondary surgeries at the operative level (only reoperations and removals were observed) have been performed on 7.9% (17/214) of the PCM patients and on 7.4% (14/190) of the control patients (p50.854). CONCLUSIONS: This randomized, prospective FDA IDE study found that the treatment of symptomatic single-level cervical spondylosis with the PCM device maintained motion and continued to achieve clinical