Experience of the Bryan Artificial Disc Replacement for Cervical Disc Disease

Abstract

Objective: The anterior cervical interbody fusion(ACIF) with autologous bone block or interbody cages with bone graft is one of the most popular treatments for cervical disc disease. However, it was reported that ACIF could cause the symptomatic adjacent segment degeneration, which required the surgical treatment up to 2.5節 3% a year. The cervical artificial disc was introduced to overcome this drawback of ACIF, and this study is to design to share the early experiences with Bryan, as well as its problems based on the clinical outcomes. Methods: We conducted the Bryan cervical artificial disc replacement for the treatment of 10 patients for 11 months, from June, 2004 to May, 2005. The mean age was 42.1 years old. Main symptoms were 6 cases of radiculopathy, 3 cases of myelopathy and 1 case of radiculomyelopathy. The lesions included 5 cases of 1 level treated with Bryan cervical artificial disc alone, 5 cases of 2 levels treated by the mixture of the Solis interbody cage and Bryan. The follow-up period varied from 4 months to 11 months. We examined symptomatic change using visual analogue scale, change of sagittal curvature, preservation of ROM at treated segment by Bryan artificial disc, change of overall curvature at C2-7 in preoperative and immediate(1節 7 days), early(1節 3 months), late(5節 11 months) postoperative periods and measured axis deviation of at arthroplasty level in immediate postoperation. Results: At discharge, the symptoms were improved in all 10 cases. Motion was preserved in the treated arthroplasty segment(mean range of motion 8.84 and 7.18 in early and late postoperative periods) for up to 11months of postoperation. In sagittal curvature at arthroplastic segment, kyphotic angle significantly increased 4.67 degree in immediate postoperation and more increased for follow up periods(11months) but statistically was not significant. Overall curvature(C2-7) was significantly not changed for 11months postoperation. By comparing preoperative and postoperative flexion and extension on lateral X-ray view, the arrangement of Bryan disc was not related to the changes of movement. Postoperative radiographic evaluations showed that the disc prosthesis were tilted to the right in A-P view in the first 2 cases, and that the shell flanges of the disc were slightly above the anterior surface of the vertebral body in 1 case. During the follow up period, neither dislocation nor subsidence into the vertebral body of Bryan artificial disc was observed. Conclusion: Although it is not yet known whether the alignment of the artificial disc can limit the ROM of the cervical spine after surgery, it can be somewhat overcome by modifying the surgical procedures and the instruments. Further studies may deal with the relationship between the alignment of artificial disc and the ROM of the involved and adjacent level, as well as the safety and efficacy of the long-term changes.