Evaluation of clinicoradiological outcomes of lateral vertebral notch referred pedicular screws entry point in subaxial cervical spine by freehand technique

Abstract

Purpose: Cervical pedicle screws (CPSs), though associated with complications and steep learning curve, have significantly increased strength and stability as compared to any other posterior instrumentation methods. Using anatomical referral techniques, pedicle screws can be inserted safely with a high accuracy rate obviating the need for anterior stabilization. Our present study aims to investigate the safety and outcomes of lateral vertebral notch (LVN) referred entry point for subaxial CPSs by freehand technique. Materials and Methods: We retrospectively studied 22 patients who underwent CPS fixation. Computed tomography (CT) scan with angiography was done in each case to know the anatomy, characteristics, and anomalies of each pedicle. Postoperative CT scan was done to look for any breach in cervical pedicles. We used free hand technique for insertion of subaxial cervical pedicles taking LVN as a reference point. The authors used the medial wall of the cervical pedicles as a safe guide for the probes that walked along it. Results: Eighty screws were inserted in total in the study group. Mean angle of screw with sagittal axis of vertebrae was 23.43° ± 9.279°. Range of angle used was 6°–40°. Perforation occurred in 11 pedicle screws: C3 (2 out of 8, 25%), c5 (3 out of 20, 15%), and c4 (4 of 22, 18%). Out of 11 perforations, four were complete and seven were partial perforations. One complete medial perforation was associated with radiculopathy that required revision. Conclusion: The technique described in the study can be considered relatively safe, easy, and reliable method of inserting cervical pedicle screws with high accuracy (86.25%) and low complication rates (1.25%). However, meticulous preoperative planning is required.

Keywords

• cervical pedicle
• freehand technique
• lateral vertebral notch
• perforation
• subaxial cervical spine