Mid-term efficacy and safety of cervical disc arthroplasty versus fusion in cervical spondylosis: A systematic review and meta-analysis

Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are the most commonly used procedures in cervical spondylosis. However, only a few published studies exist in the literature comparing these two operation types, particularly its mid-term efficacy and safety. Furthermore, in those studies, even large sample trials, when compared, have elicited controversial results, making it inconvenient for clinicians to refer to them. The aim of the present study was to clarify the advantages and shortcomings of the two procedures. Articles indexed in the PubMed, Web of Science, Cochrane Library, EMBASE, China Biological Medicine and China National Knowledge Infrastructure (CNKI) databases, as of March 2016, that met our criteria were searched. A total of 18 trials involving 3,040 patients were included in our final analysis. The most important results drawn from the present analysis were as follows: Insignificant differences were identified in the blood loss [weighted mean difference (WMD)=6.23; 95% confidence intervals (CI), −0.85 to 13.32; P=0.08], surgical time [standardized mean difference (SMD)=0.40; 95% CI, −0.01 to 0.82; P=0.06], the time of hospital stay (SMD=0.05; 95% CI, −0.28 to 0.37; P=0.77) and the total complications rate [odds ratio (OR)=0.86; 95% CI, 0.66 to 1.131; P=0.28] on a comparison of the two operation methods. By contrast, comparing CDA with ACDF, the CDA had higher Short Form survey (SF-36) scores (WMD=1.65; 95% CI, 0.61 to 2.69; P=0.002), a larger range of motion in the operation level (SMD=6.53; 95% CI, 3.89 to 9.17; P<0.0001), a higher rate of neurological improvement following the operation (OR=1.80; 95% CI, 1.29 to 2.52; P=0.0006), a lower Visual Analog Scale (VAS) score of neck pain (WMD= 0.16; 95% CI, −0.28 to 0.05; P=0.006) and arm pain (WMD= 0.12; 95% CI, −0.24 to −0.01; P=0.04). In addition, in the mid-term following the surgery, CDA had a lower Neck Disability Index (NDI; SMD=0.18; 95% CI, −0.28 to −0.07; P=0.001) and a lower reoperation rate of adjacent levels (OR=0.54; 95% CI, 0.35 to 0.85; P=0.007) compared with ACDF. Taken together, these results suggested that CDA and ACDF are efficient and safe methods for dealing with cervical spondylosis. However, with respect to certain specific indicators, such as the reoperation rate of adjacent levels following surgery, the former has several advantages.