Clinical and Computed Tomography Evaluation of Plate and Screw on the Cervical Lateral Mass: A Modified Magerl's Technique

Lee, Dong Chan; Yoon, Seung Hwan; Park, Hyung Chun; Park, Jong Oon; Hyun, Dong Keun; Park, Heon Seon

Abstract

OBJECTIVE
To determine the clinical and radiological safety of 15 consecutive patients managed with plate and screw fixation systems applied to the cervical lateral mass.
METHODS
15 patients who underwent posterior cervical and T1 arthrodesis were reviewed from Jan 2002 to Dec 2004. Posterior cervical screw and plate fixation was applied on the lateral mass of the cervical spine. The authors have tried lateral mass screw fixation using a modified Magerl's technique (20 degrees lateral and 20~30 degrees rostral screw trajectory) under preliminary radiological study. The average patient age was 39.73 degrees+/-11.00 years, and the average follow-up period was 9.73 degrees+/-6.77 months. Computed tomography scans taken after surgery were reviewed to confirm the attempted screw trajectory correct and safety.
RESULTS
Three of 93 lateral mass screws were malpositioned but clinical damage was not noted. Two of 8 pedicle screws on the T1 vertebrae were not placed on the correct pedicle area. Screw and plate loosening was observed in one case but was not subjected to an additional procedure because of maintained screw position observed during follow-up periods.
CONCLUSION
The results of this study indicate that lateral mass screw fixation using the Modified Magerl's technique on the cervical lateral mass may provide safe and effective application on the patients. In addition, the chance of incorrectly placed screws was higher in T1 pedicle screw fixation than in lateral mass screw fixation of the cervical area.