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.
Competing Interests: J.Y.,—education grant: Medtronic. R.C.S.—Research support-Medtronic, Stryker, AO, Cerapedics, Smith & Nephew, Lilly, Simplify Medical, OrthoFix, Empirical Spine, Royalties-Medtronic, Nuvasive, Saunders Elsevier. The remaining authors report no conflicts of interest.
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