Vertebral Lateral Notch as Optimal Entry Point for Lateral Mass Screwing Using Modified Roy-Camille Technique.

ABSTRACT

STUDY DESIGN: Retrospective study of 37 consecutive female patients with cervical spondylotic myelopathy who underwent reconstructed computed tomography (CT) scanning of the cervical spine. PURPOSE: The purpose of this study was to investigate whether the vertebral lateral notch of the cervical spine is an effective landmark to determine the entry point for lateral mass screwing. A modified Roy-Camille technique was used to determine the entry point associated with the lateral notch of the cervical spine. OVERVIEW OF LITERATURE The Roy-Camille technique has been a popular technique for the posterior fixation of the cervical spine. A problem with this technique is determining the entry point on the lateral mass via visual inspection, such as in cases with degenerative or destructive cervical facet joints. METHODS: Thirty-three female patients with cervical spondylotic myelopathy underwent reconstructed CT scanning of the cervical spine. Overall, 132 vertebrae from C3 to C6 were reviewed using reconstructed CT. The probable trajectory using a modified Roy-Camille technique was determined using reconstructed CT scans, and the optimal entry point was identified. Horizontal and vertical distances from the vertebral lateral notch were measured. RESULTS: The entry point determined using the modified Roy-Camille technique was significantly superior and medial compared with that determined using the conventional Roy-Camille technique. At C3 and C4 levels, the entry point using the modified technique was 1.4 mm below and 4.4 mm medial to the lateral notch, and at C5 and C6 levels, it was 2.3 mm below and 4.9 mm medial to the lateral notch. CONCLUSIONS: The vertebral lateral notch of the cervical spine was an effective landmark to determine the entry point for lateral mass screwing. The modified Roy-Camille technique proposed here may prevent surgical complications and poor outcomes.