CLINICAL ARTICLE pISSN 1738-2262/eISSN 2093-6729 Korean J Spine 9(3):137-141, 2012 www.e-kjs.org Copyright © 2012 The Korean Spinal Neurosurgery Society 137 Radiological Efficacy of Cervical Lateral Mass Screw Insertion and Rod Fixation by Modified Magerl

Objective: Cervical lateral mass screw insertion and rod fixation is a useful method for stabilizing the cervical disease, so various modified techniques were present. Many surgeons had reported the biomechanical safety according to the screw positioning method in the cervical spine, but the modified Magerl’s method (Yoon’s method) was not well studied. So, this study assessed the radiological efficacy of the modified Magerl’s method with long-term follow-up. Methods: This study retrospectively reviewed 323 lateral mass screws of 50 patients who had followed-up at least 2 years. Radiologic data were analyzed as parameters of complications after operation, including kyphotic or lordotic change, bone fusion, pull-out or malposition of screw, foraminal stenosis, adjacent disc degeneration or aggravation, pseudoarthrosis, and vertebral artery injury. Results: The mean follow-up period was 32 (24 to 52) months. There were kyphotic changes in 4.0 % (2 of 50 cases). Unsuccessful bone fusion occurred in 4.0%(2 of 50 cases). Among the 323 screws, screw pull-out (4.0%. 2 of 50cases, 3 of 323 screws), foraminal invasion (1.2 % of total screws), and facet injury (0.6 % of total screws) occurred. Conclusion: The lateral mass screw insertion and rod fixation by the modified Magerl’s method (Yoon’s method) is a safe and reliable technique with low rate of complication related to instruments in minimum 2 years follow-up. Key Words: Spinal fusionㆍRadiological assessmentㆍModified Magerl’s methodㆍYoon’s methodㆍLong-term follow-u