Clinical Outcomes of Treating Cervical Adjacent Segment Disease by Anterior Cervical Discectomy and Fusion Versus Total Disc Replacement: A Systematic Review and Meta-Analysis

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To compare clinical outcomes of all available adjacent segment disease (ASD) cohorts being treated by either anterior cervical discectomy and fusion (ACDF) or total disc replacement (TDR). METHODS: We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. Searches of electronic databases from inception to August 2017 identified 349 articles for screening. Data was extracted and analyzed using meta-analysis of proportions. RESULTS: The search identified 1 double-armed study and 8 single-armed studies from which data of 5 TDR and 5 ACDF cohorts treating ASD were extracted. Between the 2 pooled TDR (n = 103) and ACDF (n = 258) groups, baseline characteristics were predominantly similar. Compared with ACDF, TDR demonstrated superior operation duration (107 vs 188 minutes, P = .011) and range of motion of C2-C7 at final follow-up at least 1 year after surgery (40.2° vs 35.1°, P = .001). Other surgical and performance parameters including estimated blood loss, complications, and Japanese Orthopedic Association score, Neck Disability Index, Visual Analog Scale neck, and Visual Analog Scale upper limb measures were comparable between cohorts. CONCLUSION: TDR confers similar surgical and postoperative outcomes to the treatment of ASD as ACDF. Both procedures lead to improvement in all performance outcomes. Larger, prospective, randomized studies will validate the findings of this meta-analysis. Longer term studies are required to ascertain the recurrence rates of ASD following either surgical treatment of primary ASD.