Mid-Term to Long-Term Outcomes After Total Cervical Disk Arthroplasty Compared With Anterior Diskectomy and Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

STUDY DESIGN: This study was a meta-analysis of published randomized controlled trials (RCTs). OBJECTIVE: We investigated the mid-term to long-term outcomes of cervical disk arthroplasty (CDA) versus anterior cervical diskectomy and fusion (ACDF) for the surgical treatment of symptomatic cervical disk degenerative disease. SUMMARY OF BACKGROUND DATA: ACDF has been widely performed for the surgical treatment of symptomatic cervical disk degenerative disease. However, the loss of motion at the operated level has been hypothesized to accelerate adjacent-level disk degeneration. CDA was designed to preserve motion segments and decrease the risk/rate of adjacent segment degeneration. However, it is still uncertain whether mid-term to long-term outcomes after CDA is more effective and safer than those observed after ACDF. METHODS: Two independent reviewers conducted a search of PubMed, Embase, and the Cochrane Library databases for RCTs with a minimum of 48 months of follow-up. For dichotomous variables, the risk ratio and 95% confidence intervals were calculated. For continuous variables, the standardized mean difference and 95% confidence intervals were calculated. RESULTS: Eleven RCTs, finally, were included. The rate of neurological success in the CDA group was not significantly different from that in the ACDF group. The pooled results show that patients who underwent CDA had a significantly greater improvement in Neck Disability Index (NDI) and Short Form 36 Health Survey physical component (SF-36 HSPC) than did those who underwent ACDF. No significant difference was found when comparing the neck and arm pain scores between the CDA and ACDF groups. The overall rate of secondary surgical procedures was significantly lower in patients who underwent CDA than in those who underwent ACDF. We observed similar overall rates of adverse events and adjacent segment degeneration when comparing the CDA group with the ACDF group. CONCLUSIONS: This meta-analysis provides evidence suggesting that CDA was superior to ACDF in terms of NDI score, SF-36 HSPC score, and low rate of secondary surgical procedures. Furthermore, no significant differences existed between the CDA group and the ACDF group in the neck pain visual analog scale score, arm pain visual analog scale score, the rate of neurological success, adjacent segment degeneration, and adverse events. LEVEL OF EVIDENCE: Level 1.