THE UTILITY OF 3-DIMENSIONAL-NAVIGATION IN THE SURGICAL TREATMENT OF CHILDREN WITH IDIOPATHIC SCOLIOSIS

Abstract

Objective. To evaluate the accuracy of screw placement using preoperative 3D CT-based navigation with intraoperative fluoroscopic guidance compared with freehand placement. Material and Methods . Intraoperative registration of patient anatomy to preoperative 3D-CT using anatomic landmarks was performed in 62 patients aged 12-18 years with mean deformity 67° (range, 52° to 80°). When registration accuracy was high, screw tracts were drilled under navigation guidance. When the error was >1.0 mm, registration was performed using posterior vertebral bone structures. The times required for tracker placement, registration, and screw track formation, as well as the number of passes were documented. Results were compared with outcomes in cases operated on with freehand screw placement. Results . In the navigation group, 710 pedicle screws were placed. Mean times were 55 seconds for tracker placement, 94.5 seconds per vertebra for patient registration, 131.1 seconds for screw tract formation on the concave side of the deformity, and 129.5 seconds on the convex side. In the freehand group, 470 pedicle screws were placed. Average time for screw placement was 135.2 seconds, pedicle integrity was breached in 5.1 % of trajectories. Conclusion . Intraoperative optic fluoroscopic navigation based on anatomic landmark registration to preoperative 3D-CT spine images enables precise pedicle screw placement.