ABSTRACT
OBJECTIVE: Since the 1990s, due to postoperative loss of mobility and adjacent segmental disease after anterior cervical fusion, many different types of cervical artificial discs have been developed as alternative implants. The purposes of this study are investigation and comparison of radiographic and clinical outcomes between two different types of prostheses, Bryan(R) and Mobi-C(R). METHODS: We retrospectively evaluated 33 patients who were treated for cervical degenerative disc disease that resulted in radiculopathy and/or myelopathy between May 2004 and April 2009. Seventeen patients underwent Bryan(R) cervical disc arthroplasty and sixteen patients underwent Mobi-C(R) arthroplasty. The radiographic outcomes were assessed by measuring the cervical lordosis, segmental lordosis, range-of-motion (ROM) of the cervical spine (C2-7), functional segmental unit (FSU), prosthesis' shell and the upper adjacent segment. The clinical results were evaluated according to the Visual Analogue Scale (VAS) for axial pain and radiculopathy, Odom's criteria, and the modified Prolo's economic and functional outcome rating scale. RESULTS: The age of the study population ranged from 24 to 69 years with a mean age of 48 years vs. 46 years in the Bryan(R) and Mobi-C(R) groups, respectively. The mean duration of follow-up was 23.7 months in the Bryan(R) group and 11.3 months in the Mobi-C(R) group. The changes of overall cervical sagittal angle were not significantly different between two groups, but the increase of segmental sagittal angle (0.85degrees in Bryan(R), 8.04degrees in Mobi-C(R)), ROM of the FSU(-0.51degrees in Bryan(R), 2.47degrees in Mobi-C(R)) and ROM of the shell (1.77degrees in Bryan(R), 5.28degrees in Mobi-C(R)) were significantly higher in Mobi-C(R) group than in Bryan(R) group (p<0.05). The clinical results were not significantly different between two groups. CONCLUSION: The Mobi-C(R) prosthesis showed more favorable radiographic results than that of the Bryan(R) prosthesis, however, the clinical outcomes were similar in both groups. Large-scale and long-term follow-up studies are needed to confirm our results.