Anterior Cervical Discectomy And Fusion (ACDF) Versus Cervical Disc Arthroplasty (CDA) For Two Contiguous Levels Cervical Disc Degenerative Disease: A Meta-analysis Of Randomized Controlled Trials

Background Anterior cervical discectomy and fusion(ACDF)has been considered as a gold standard for symptomatic cervical disc degenerative disease, which may lresult in progressive degeneration or disease of the adjacent segments.the artificial cervical disc was designed to reduce the number of lesions in the adjacent segment.Many clinical studies have demonstrated the superiority of cervical disc arthroplasty(CDA) for anterior cervical discectomy and fusion in single segment cervical disc degeneration disease.But fot two contiguous levles cervical disc degenerate disease,which kind of treatment method is better,is controversial.Purpose To evaluate the clinical effects requiring surgical intervention between anterior cervical discectomy and fusion(ACDF) and cervical disc arthroplasty(CDA) at two contiguous levels cervical disc degenerative disease.Methods We conducted a comprehensive search in multiple databases,including Pub Med, Cochrane Central Register of Controlled Trials, EBSCO and Embase.we identified 6 reports meet inclusion criteria. Two independent reviewers performed the data extraction from archives.Data analysis was conducted with Rev Man 5.3.Results After applying inclusion and exclusion criteria,six papers were included in meta-analyses.the overall sample size at baseline was 650 patients(317 in the TDR group and 333 in the ACDF group).The results of the meta-analysis indicated that the CDA patients was had significantly superiorities in Mean blood loss(P<0.00001,standard mean differences(SMD)=-0.85;95%confidence interval(CI) =-1.22 to-0.48);Reoperation(P=0.0009,risk ratio(RR)=0.28, 95%confidence interval(CI) = 0.13 to 0.59), Adjacent segment disease(P<0.00001,risk ratio(RR)=0.48, 95% confidence interval(CI) = 0.40–0.58)and Improvement in neck disability index(P=0.002,SMD=0.31, 95%CI=0.12 to 0.50).No significant difference was identified between the two groups regarding mean surgical time(P=0.84,SMD=-0.04, 95%CI=-0.40 to 0.32),neck and arm pain scores(P=0.52,SMD=0.06, 95%CI=-0.13 to 0.25) reported on a visual analog scale and rate of postoperate complications[risk ratio(RR)=0.79; 95%CI=0.50 to 1.25; p=0.31].The CDA group of sagittal range of motion(ROM) of the operated and adjacent levels, functional segment units(FSU) and C2-7 is superior than ACDF group by radiographic data of peroperation, postoperation and follow-up.Conclusion This meta-analysis revealed that the clinical safety and efficacy of CDA are equivalent or superior to ACDF at two contiguous levels cervical disc degenerative disease.