Preliminary Radiological Outcomes of Cervical Arthroplasty with Bryan and Prestige LP Cervical Disc Prosthesis

ABSTRACT

OBJECTIVE: Postoperative motion preservation and prevention of adjacent segment degeneration is well recognized after placing artificial cervical disc prosthesis in patients with degenerative cervical disc disease. The authors investigated postoperative changes in motion dynamics in two different types of artificial cervical disc prosthesis, Bryan and Prestige LP cervical disc prosthesis, and compared them. METHODS: Twenty five patients underwent anterior cervical discectomy and implantation of artificial cervical disc prosthesis 10 with Bryan and 15 with Prestige LP. Radiological assessments, including overall sagittal alignment angle, range of motion (ROM) of overall sagittal, functional spine unit (FSU) angle, segmental ROM of FSU and ROM of adjacent segment (Upper and Lower level) using static and dynamic lateral radiographs, were performed preoperatively and postoperatively. The mean postoperative follow up period was 18.6 months (range 10.4~28.5) in Bryan and 9.2 months (range 6.5~12.6) in Prestige LP. RESULTS: The overall sagittal alignment angle was decreased 2.9degrees in Bryan group (p=0.033) and increased 5.7degrees in Prestige LP group (p=0.017). The FSU angle at treated level was decreased 0.4degrees in Bryan group (p=0.929) and increased 2.9degrees in Prestige LP group (p=0.008). The ROM of overall sagittal was decreased in both groups (Bryan 8.6degrees p=0.075, Prestige LP 2.9degrees p=0.182). The segmental ROM of FSU was increased 1.0degrees in Prestige LP group (p=0.191) but, decreased 0.6degrees in Bryan group (p=0.929). The ROM of adjacent segment was decreased in both groups (Bryan upper p=0.023 lower p=0.050, Prestige LP upper p=0.570 lower p=0.132). The postoperative radiological results of comparison between two different artificial disc showed that overall sagittal alignment angle and FSU angle were more increased in Prestige LP (p=0.005, p=0.026, respectively). CONCLUSION: The segmental ROM of FSU was preserved and ROM of adjacent segment was decreased in both groups. This means that postoperative adjacent segment disease may be prevented regardless of types of implants. On comparison study, postoperative cervical curvature was more lordotic in Prestige LP. Therefore, Prestige LP is more suitable to maintain postoperative cervical lordosis. The limitation of our study is small number of case and short and unequal follow up period between two types of implants. Further long term study will be needed.