Background context: 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).
Purpose: 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.
Study design/setting: The study was conducted at 13 sites. A noninferiority design with a 1:1 randomization was used.
Patient sample: Two hundred nine patients were randomized and treated (106 ACDF; 103 ProDisc-C).
Outcome measures: 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.
Methods: 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.
Results: 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.
Conclusions: 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.