Early Radiologic Outcome of Cervical Artificial Disc Surgery

Kim, Myung Hyun; Cho, Do Sang

Abstract

OBJECT: Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of Bryan cervical disc prosthesis. METHOD: The authors retrospectively reviewed radiographic and clinical outcomes in 49 patients who received the Bryan Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of the FSU, and the C2-7 Cobb angle. The range of motion(ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria. RESULT: A total of 66 Bryan disc were placed in 49 patients. A single-level procedure was performed in 35 patients, a two-level procedure in 14 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria. The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level. 90% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 89.4% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 57.7% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 62.5% of the patients postoperatively.
CONCLUSION
Arthroplasty using the Bryan disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although early and intermediate results are promising, this is also a relatively new approach, long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.