Bryan cervical disc prostheses: preservation of function over time.

摘要

Preserving the function of cervical disc prostheses, even over the short term, is a matter of concern among surgeons. Our case series highlights our results and protocol for increasing the probability of continued device function. Twenty-five consecutive patients with a mean (+/-SEM) age of 44.3+/-8.3 years underwent 29 cervical total disc arthroplasties for disc herniations. Three patients underwent primary bilevel arthroplasty, and one patient underwent a second arthroplasty for another herniation 2 years after the first. Prosthesis ranges of motion were measured using dynamic plain X-ray studies and compared to the ranges of motion of adjacent segments. At follow-up, all prostheses were in the correct location and without subsidence. All displayed firm secondary stability. One segment had fused. Twenty-eight of 29 devices were mobile an average of 9.5 degrees +/-4.7 degrees (range 3 degrees to 20 degrees ) (for all 29 devices the average movement angle was 9.2 degrees +/-5 degrees ; range 0 degrees to 20 degrees ), 25 upper adjacent segments were mobile an average of 10.9 degrees +/-4.5 degrees (range 2 degrees to 20 degrees ) (excluding the fused prosthesis: 11 degrees +/-4.6 degrees ) and 15 lower adjacent segments were mobile an average of 9.8 degrees +/-6 degrees (range 1 degrees to 21 degrees ). With our protocol, 28 of 29 cervical disc prostheses in 25 consecutive patients were mobile after an average of 22.3+/-9.4 months. Prosthesis motion was physiological and very similar to that of the healthy adjacent segments. Long-term studies including larger numbers of patients are required to validate our initial observations.