iCT Navigation for Transpedicular Screw Fixation in the Thoracolumbar Spine: Experience in 100 Consecutive Cases

Background: Various guidance techniques have been developed for optimal pedicle screw placement. We present our initial experience with intraoperative CT (iCT) navigation for transpedicular screw fixation in the thoracolumbar spine. Objective: This study aimed to describe the accuracy and reliability of iCT navigation for transpedicular screw fixation. Material and Methods: One hundred consecutive patients underwent thoracolumbar pedicle screw fixation under iCT navigation. After iCT registration of the local bony anatomy with a firmly attached spinous process tracker, pedicle screw placement was performed under navigation with an infrared camera and infrared reflectors on insertion instruments. Screw trajectories of the intraoperative verification CT were matched against the navigation paths. Radiological and clinical follow-up was prospectively documented and retrospectively analyzed. The study included 47 women and 53 men with a mean age of 66 years. Indications for thoracolumbar pedicle fixation were degenerative instability with stenosis, cyst or disc herniation (82), spondylolytic instability (9), scoliosis with stenosis (6), and traumatic fractures (3). A total of 443 pedicle screws were inserted: 22 in the thoracic spine, 371 in the lumbar spine, and 50 in S1. Results and Conclusions: Four hundred thirty-five out of 443 screws (98%) were correctly placed. Misplacement was explained by loosened infrared reflectors on pedicle awl or probe, or by the displacement of the spinous process tracker; misplaced screws were re-inserted intraoperatively and showed correct placement on the second verification CT. Based on our first 100 cases, iCT navigation for transpedicular screw fixation in the thoracolumbar spine seems to be very accurate and reliable.