What is the superior surgical strategy for bi-level cervical spondylosis-anterior cervical disc replacement or anterior cervical decompression and fusion?: A meta-analysis from 11 studies

BACKGROUND: Nowadays, anterior cervical artificial disc replacement (ACDR) has achieved favorable outcomes in treatment for patients with single-level cervical spondylosis. However, It is still controversial that whether or not it will become a potent therapeutic alternation in treating 2 contiguous levels cervical spondylosis compared with anterior cervical decompression and fusion (ACDF). Therefore, we conducted a systematic review and meta-analysis to compare the efficacy and safety of ACDR and ACDF in patients with 2 contiguous levels cervical spondylosis. METHODS: According to the computer-based online search, PubMed, Embase, Web of Science, and Cochrane Library for articles published before July 1, 2017 were searched. The following outcome measures were extracted: neck disability index (NDI), visual analog scale (VAS) neck, VAS arm, Short Form (SF)-12 mental component summary (MCS), SF-12 physical component summary (PCS), overall clinical success (OCS), patient satisfaction (PS), device-related adverse event (DRAE), subsequent surgical intervention (SSI), neurological deterioration (ND), and adjacent segment degeneration (ASD). Methodological quality was evaluated independently by 2 reviewers using the Furlan for randomized controlled trial (RCT) and MINORS scale for clinical controlled trials (CCT). The chi-squared test and Higgin I(2) test were used to evaluate the heterogeneity. A P < .10 for the chi-squared test or I(2) values exceeding 50% indicated substantial heterogeneity and a random-effect model was applied; otherwise, a fixed-effect model was used. All quantitative data were analyzed by the Review Manager 5.2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). RESULTS: Nine RCTs and 2 CCT studies containing 2715 patients were included for this meta-analysis. The pooled analysis indicated that the ACDR group is superior to ACDF in NDI, VAS neck, PCS score, OCS, PS, DRAE, ASD, and SSI. However, the pooled results indicate that there was no significant difference in the ND, VAS arm and in MCS score. CONCLUSIONS: The present meta-analysis suggests that for bi-level cervical spondylosis, ACDR appears to provide superior clinical effectiveness and safety effects than ACDF. In the future, more high-quality RCTs are warranted to enhance this conclusion.