Clinical Correlation with Postoperative Computed Tomography Assessment of the Accuracy of Lumbar Pedicular Screws Insertion

Abstract

Background: Pedicle screw instrumentation is widely used in the lumbar spine as a means of stabilization to enhance arthrodesis. For accuracy, pedicle screw instrumentation may be guided by anatomic landmarks, preoperative imaging, and intraoperative imaging tools such as plain radiography, fluoroscopy, and, more recently, image-guided technology. Objective: Improving accuracy of lumbar pedicular screws insertion and clinical outcome of patients undergoing lumbar pedicular fixation. Patients and Methods: This cohort study was done at Neurosurgery Department at Alexandria Armed Forces Hospital and Neurosurgery Department in Zagazig University. Assuming that attendance rate of patients for lumbar pedicular fixation is 3 patients per month, the sample size was 36. All patients were taken as a comprehensive sample. Patients confirmed to have been underwent transpedicular lumbar fixation. Results: In assessing 153 pedicle screws inserted in 36 patients. Out of 51 misplaced screws; lateral screw misplacement was observed in 28 screws (54.9 %) and medial pedicle wall violation in 22 screws (43.1 %) and inferior misplacement in one patient. The remaining 102 screws (67.55 %) were judged as correctly inserted. Of the 51 misplaced screws, 34 misplaced screws were classified as minor (cortical perforation ≤ 2 mm), 15 screws moderate (2–4 mm), and 2 screws severe penetration (> 4 mm). Conclusion: Pedicle screw insertion carries risk of pedicular wall violation even in experienced hands even though intraoperative fluoroscopy is used. However; most violations are minimal with no clinical consequences and can be evaluated best by CT scan not plain X-ray.