Study Design. Single institution, prospective cohort study of 21 patients who underwent single- or bilevel cervical disc arthroplasty for radiculopathy.
Objective. To evaluate the long-term outcome of cervical disc arthroplasty.
Summary of Background Data. There is an increasing trend in the use of cervical arthroplasty; however, no long-term outcome studies exist to verify their safety, functionality, and durability.
Methods. A total of 21 patients underwent 27 total disc arthroplasties using the Bryan cervical disc (Medtronic Sofamor Danek Inc, Memphis, TN) after anterior cervical discectomy. Clinical and radiological data were obtained from the 8-year postoperative review.
Results. Nineteen of twenty-one patients were able to perform daily activities without limitation. Twenty of twenty-one patients reported fair to excellent outcome according to Odom criteria and 21 of 27 (78%) operated segments were mobile. Functional prostheses moved an average of 10.6°, which was similar to the range of movement of the adjacent nonoperated segments of the cervical spine. Heterotopic ossification was evident in 13 of the 27 (48%) operated segments and restricted movement of the prosthesis in nine cases. Five of the six patients who received bilevel arthroplasties developed heterotopic ossification. There was one case of posterior migration of the prosthesis, which did not have any clinical repercussion. No other case showed evidence of migration, subsidence, loosening, or wear. Radiological evidence of adjacent segment degeneration was observed in four patients (19%); however, each of these patients had pre-existing degenerative disc disease at these levels on preoperative imaging.
Conclusion. At 8-year follow-up, the Bryan cervical disc arthroplasty maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome in the majority of cases. However, the incidence of heterotopic ossification causing restricted range of movement of the prosthesis appears to increase with time, especially in bilevel procedures.