Background. The controversy concerning the benefits of unisegmental cervical disc arthroplasty (CDA) over anterior cervical discectomy and fusion (ACDF) is still open because some randomised clinical trial (RTC) comparing ACDF with CDA have been highly inconclusive. Most of these studies mixed disc prosthesis with dissimilar kinematic characteristics. To date, a compilation of the clinical and radiologic outcomes and adverse events of anterior cervical discectomy and fusion (ACDF) compared with a single cervical disc arthroplasty (CDA) design, the Bryan disc has partially accomplished. Methods. This is a systematic review of RCTs with level I-II evidence. Only RCTs reporting clinical outcomes were included in this review. After a search on different databases including PubMed, Cochrane Central Register of Controlled Trials, and Ovid MEDLINE, a total of 10 RCTs out of total 51 studies were entered in the study. RTC's were searched from the earliest available records in 2005 to December 2014. Results. Five studies were Level I, and five were Level II. Out of a total of 1101 patients, 562 patients were randomly assigned into the Bryan arthroplasty group and the remaining 539 patients into the ACDF group. The mean follow-up was 30.9 months. Patients undergoing CDA had lower Neck Disability Index, and better SF-36 Physical component scores than ACDF patients. Patients with Bryan CDA had also less radiological degenerative changes at the upper adjacent level. Overall adverse events were twice more frequent in patients with ACDF. The rate of revision surgery including both adjacent and index level were slightly higher in patients with ACDF, showing no statistically significant difference. Conclusions. This review of evidence level I-II RCTs comparing clinical and radiological outcomes of patient undergoing Bryan arthroplasty or ACDF indicated a global superiority of the Bryan disc. The impact of both surgical techniques on the cervical spine (radiological spine deterioration and/or complications) was more severe in patients undergoing ACDF. However, the rate of revision surgeries at any cervical level was equivalent for ACDF and Bryan arthroplasty. These data suggest that even though the loss of motion has a determinant influence in the development of degenerative changes in ACDF cases, these kinematic factors do not imply a higher rate of symptomatic adjacent segment degeneration requiring surgery. Level of Evidence. Level I