Treatment of Cervical Myelopathy: Long-term Outcomes of Arthroplasty for Myelopathy Versus Radiculopathy, And Arthroplasty Versus Arthrodesis for Myelopathy.

STUDY DESIGN: Analysis of 2- and 7-year outcomes from a clinical trial comparing 2-level cervical disk arthroplasty (CDA) to anterior cervical discectomy and fusion (ACDF) in 287 patients with radiculopathy alone, and 110 patients with myelopathy alone or myelopathy with radiculopathy. OBJECTIVE: To compare the long-term safety and effectiveness of CDA for myelopathy versus radiculopathy. SUMMARY OF BACKGROUND DATA: CDA for myelopathy is safe and effective in short term. MATERIALS AND METHODS: We analyzed Neck Disability Index (NDI), neck/arm pain, SF-36, neurological status, adverse events (AEs), and secondary surgeries at index and adjacent levels. RESULTS: All groups improved significantly for NDI, neck/arm pain, and physical component summary (PCS) scores from preoperative to postoperative. CDA Myelopathy versus CDA Radiculopathy: 2- and 7-year improvements were not significantly different. The 7-year score improvements for CDA Myelopathy and CDA Radiculopathy were: NDI (37.8 vs. 35.8, P=0.352), neck pain (12.0 vs. 12.1, P=0.477), arm pain (11.6 vs. 9.6, P=0.480), and PCS (14.1 vs. 13.7, P=0.863). The 2 groups had similar proportions of patients who maintained or improved their neurological status (87.2% vs. 93.5%, P=0.218), similar rates of serious AEs (54.5% vs. 57.5%, P=0.291) and similar rates of secondary surgeries at index (3.7% vs. 4.4%, P=0.839) and adjacent levels (3.7% vs. 7.6%, P=0.367). CDA Myelopathy versus ACDF myelopathy: 2 and 7-year improvements were not significantly different. The 7-year CDA and ACDF score improvements were: NDI (37.8 vs. 31.1, P=0.147), neck pain (12.0 vs. 10.4, P=0.337), arm pain (11.6 vs. 11.4, P=0.791), and PCS (14.1 vs. 11.2, P=0.363). The 2 groups had statistically similar proportions who maintained or improved their neurological status (87.2% vs. 96.2%, P=0.409), statistically similar overall rates of secondary surgeries at the index levels (3.7% vs. 9.4%, P=0.374), and statistically similar rates of secondary surgeries at adjacent levels (3.7% vs. 15.4%, P=0.088). CDA group demonstrated lower rates of serious AEs than ACDF (54.5% vs. 65.9%, P=0.019). CONCLUSIONS: CDA for myelopathy is a safe and effective long-term treatment