Clinical and radiographic results of Bryan cervical total disc replacement: 4-year outcomes in a prospective study.

ABSTRACT

INTRODUCTION: Early results have indicated that the Bryan cervical total disc replacement (TDR) favorably compares to anterior cervical decompression and fusion, while it is associated with fewer complications and higher levels of satisfaction. In this study, we sought to prospectively report the midterm outcomes of the Bryan TDR. PATIENTS AND METHODS: A total of 20 patients had performed their 4-year follow-up visit and had been assessed clinically and radiologically. Clinical outcomes (JOA, VAS, NDI, SF-36) and ROM measurements were investigated preoperatively and at 1 and 6 months, and 1, 2 and 4 years after operation. Complications were also investigated. Occurrences of heterotopic ossifications (HOs) and adjacent-level degeneration (ALD) radiographic changes were detected from 4-year follow-up X-rays. RESULTS: The mean JOA score, VAS score for arm and neck, NDI score and SF-36 score for PCS and MCS were reduced significantly at each postoperative time point when compared with the preoperative condition. The range of movement of the cervical spine, functional spinal unit, treated segment and the adjacent segment temporarily decreased at the early assessment, but all recovered to preoperative levels over a 6-month to 4-year time period. HO was evident in 6 of the 23 operated segments, which did not restrict the movement of the prosthesis. No obvious ALD was found on MRI. There were no cases of prosthesis migration, subsidence, loosening or wear. CONCLUSION: The midterm outcomes demonstrated that the Bryan TDR maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome. There were no serious complications or cases of prosthetic wear or failure. The long-term benefits are yet to be examined.