Clinical and radiographic results after treatment of cervical degenerative disc disease with the bryan disc prosthesis: a prospective study with 2-year follow-up.

The purpose of this study was to prospectively evaluate the clinical and radiographic results obtained with the Bryan disc prosthesis (Medtronic Sofamor Danek, Memphis, TN) in 20 consecutive patients with single-level or two-level cervical degenerative disc disease. All patients were followed up for at least two years. The mean Neck Disability Index and the visual analogue scale for neck and arm pain scores were significantly reduced for all postoperative periods compared with the mean preoperative values. SF-36 outcome measures, including the physical and mental component scores, significantly improved after surgery and remained unchanged or improved at two years postoperatively. According to Odom's scale, 18 patients (90%) had good to excellent outcomes. The range of movement of the cervical spine, of the functional spinal unit, the treated segment and the adjacent segment temporarily decreased at the early assessment, but all recovered to preoperative levels over a 6-24 months time period. There was no heterotopic ossification at the implanted levels, no adjacent level degeneration and no prosthesis subsidence or excursion. Cervical disc replacement using the Bryan disc prosthesis appeared to be safe and demonstrated encouraging clinical and radiological outcomes. However, further studies are required to assess the long-term efficacy of this prosthesis and its protective influence on adjacent levels.