Early follow-up outcomes after treatment of degenerative disc disease with the discover cervical disc prosthesis

BACKGROUND CONTEXT: Although anterior cervical decompression and fusion has been used successfully in the treatment of symptomatic radiculopathy and/or myelopathy, biomechanical studies have suggested possible deleterious effects of cervical fusion on adjacent level kinematics. The emergence of cervical arthroplasty as an alternative to arthrodesis may restore a more normal spinal movement and reduces a kinematic strain on adjacent segments. To date, with existing prostheses, the risk adjacent segment disease has not been proven to be reduced using artificial disc replacement. PURPOSE: The study was designed to investigate the surgical techniques and clinical effects of the Discover artificial cervical disc prosthesis in a Chinese population and observe the stability and range of movement in the early and immediate postoperative period. STUDY DESIGN/SETTING: Our clinical study design was prospective, concurrently enrolled, and single-center trial of the artificial cervical disc prosthesis (DePuy Spine, Raynham, MA, USA) in the treatment of patients with single-and two-level degenerative disc disease of the cervical spine. PATIENT SAMPLE: Procedure was performed in 25 patients. OUTCOME MEASURES: The functional spinal unit (FSU) and global angles, segmental and overall range of motion, FSU heights, and clinical parameters checked with Neck Disability Index (NDI), Japanese Orthopedic Association (JOA), Odom's scale, and visual analog scale (VAS) pain score were assessed. METHODS: Twenty-five patients (26 discs) consecutively underwent cervical arthroplasty using the Discover artificial cervical disc in our hospital. Clinical and radiologic follow-up was performed. The radiographic parameters evaluated included the treated segments and the overall curvature of the cervical spine. RESULTS: All the patients were assessed between 12 months and 18 months after surgery (average 15.3 months). According to Odom's scale, all 25 patients (26 levels) had good to excellent outcomes by independent assessment. Mean NDI, JOA, and VAS scores showed statistical improvements in the early and immediate postoperative period. The range of movement recovered to the preoperative value during the follow-up. The treated segment ultimately showed preservation of movement when compared with preoperative levels. No prosthesis subsidence or excursion was identified, and no heterotopic ossification was found in the replaced levels. CONCLUSION: These early results from a small cohort demonstrate that cervical arthroplasty with the Discover artificial cervical disc for the treatment of degenerative cervical disc disease may provide a good clinical outcome and preserves some motion postoperatively. Although early outcomes are promising, this is also a relatively new technology and prosthesis, long-term follow-up studies with larger patient numbers are required to assess safety and efficacy compared with alternative treatments. (C) 2011 Elsevier Inc. All rights reserved.