Mid- to long-term outcomes after cervical disc arthroplasty compared with anterior discectomy and fusion: a systematic review and meta-analysis of randomized controlled trials

To evaluate the mid- to long-term clinical outcomes after cervical disc arthroplasty (CDA) as compared with anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic cervical disc disease. A systematic review and a meta-analysis were performed for articles published up to March 2013. Randomized controlled trials that reported mid- to long-term outcomes (a parts per thousand yen48 months) after CDA as compared with ACDF were included. Two authors independently extracted the articles and the predefined data. Five US Food and Drug Administration randomized controlled trials that reported 4-6 years of follow-up data were retrieved. Patients who underwent CDA had a lower mid- to long-term rate of reoperation and had greater mid- to long-term improvements in the Neck Disability Index, neck and arm pain scores, and Short Form 36 Health Survey physical component score than did those who underwent ACDF. Segmental motion was maintained in patients who underwent CDA. The mid- to long-term rates of adjacent segment disease and neurological success were not significantly different between the two groups. CDA may result in better mid- to long-term functional recovery and a lower rate of subsequent surgical procedures than ACDF would. A review of the literature showed that only an insufficient number of studies had investigated adjacent segment disease; therefore, it is mandatory that adequate future research should focus in this direction.