Study design: This is a meta-analysis of controlled trials.
Objective: To assess the overall condition of adjacent segment of cervical disk arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF).
Summary of background data: With the increase in CDA and ACDF, surgeons are taking more attention to adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis). There are more and more meta-analyses comparing the efficacy of CDA with ACDF, however, there are few meta-analyses referring to adjacent segment parameters, and investigators are still unable to arrive at the same conclusion.
Methods: Several important databases were searched for controlled trials comparing CDA and ACDF before February 2016 according to PRISMA guidelines. The analysis parameters included follow-up time, operative segments, cervical range of motion (ROM), adjacent segment motion, ASDeg, ASDis and adjacent segment reoperation. The risk of bias scale and Newcastle-Ottawa Scale were used to assess the papers. Subgroup analysis and sensitivity analysis were used to analyze the reason for high heterogeneity.
Results: Forty-one controlled trials fulfilled the inclusion criteria, including 36 English papers and 5 Chinese. The average follow-up time of all included patients was 39 months. Compared with ACDF, the rate of adjacent segment reoperation in the CDA group was significantly lower (P<0.01), and the advantage of CDA group increased with the increasing of follow-up time according to subgroup analysis. The rate of ASDeg in CDA was significantly lower than that of ACDF (P<0.01). There was no statistical difference between upper and lower ASDeg using the same surgical method (P>0.05). CDA provided a greater cervical ROM than did ACDF (P<0.01). There was a lower adjacent segment ROM and the rate of ASDis in CDA compared with ACDF (P<0.05).
Conclusions: Compared with ACDF, the advantages of CDA were lower ASDeg, ASDis, adjacent segment reoperation and adjacent segment motion; and higher cervical ROM. However, there was no statistical difference between upper and lower adjacent segment ROM/ASDeg using the same surgery.