The new Frenchay artificial cervical joint: results from a two-year pilot study.

Study Design: A clinical prospective observational cohort study of 15 patients undergoing cervical intervertebral disc replacement.

Objective: To assess the safety, clinical stability, and capacity of a newly designed cervical intervertebral disc replacement for preserving motion in the cervical spine of patients with degenerative disc disease.

Summary Of Background Data: Anterior cervical discectomy and interbody fusion results in loss of motion segments and there is evidence of accelerated degenerative changes occurring at adjacent levels. Intervertebral disc replacement may be a valid alternative to fusion. There is a need for cervical disc replacement to be evaluated in prospective studies before it can be adopted as an acceptable surgical technique.

Methods: The study enrolled 15 patients with cervical radiculopathy or myelopathy and radiologically confirmed cervical disc herniation or posterior vertebral body osteophytes. Eligibility for the study required that patients have either a previous adjacent-level surgical or congenital spinal fusion or radiologic evidence of adjacent-level degenerative disc disease. After decompressive surgery via an anterior approach, all 15 patients received the artificial joint. Follow-up visits were at set intervals and included clinical examination, radiologic assessment, and evaluation by patient-completed questionnaires.

Results: In all cases, the artificial joint maintained motion at the operative levels while reestablishing intervertebral height. The procedure was considered safe for experienced spine surgeons to perform, and the device was stable, with no dislocation of components or backing out of screws. Two screws broke, but without any consequence. Improvements in assessment scores were noted.

Conclusions: Cervical intervertebral motion can be maintained with the new device, which is clinically stable. Meticulous attention must be paid to the surgical technique to maximize the chances of a good result. The pilot study was successful, although it has yet to be determined what conditions will benefit most from this technology.