Abstract

Objectives: The purpose of this study is to describe a surgical technique and the accuracy of pedicle screw fixation under navigation guidance based on O-arm. Design: Prospective study Methods: Instrumentation using transpedicular screw fixation was performed using navigation guidance based on O-arm with 19 patients (78 screws). Evaluation of screw placement in every case was done on each instrumented vertebra by using intraoperative O -arm and plain X-ray. Screw placements were graded as good if the screws were placed in the central core of the pedicle and the cancellous portion of the body. Screw placements were graded as fair if the screws were placed slightly eccentrically, causing erosion of the pedicle cortex, and with less than a 2-mm perforation of the pedicular cortex. Screw placements were graded as poor if the screws were placed eccentrically with large portion of the screw extending outside the cortical margin of the pedicle and with more than a 2-mm perforation of the pedicular cortex, causing erosion of the pedicle cortex, and with less than a 2-mm perforation of the pedicular cortex. Results: 1 patient was excluded due to connection error between O-arm and navigation. A total 72 pedicle screws were placed in 18 patients. 94.4% (68/72) were categorized as good; 5.6% (4/72), fair; and 0% were poor. All 4 fair screws were placed extending lateral margin of the pedicle without any neurologic complications. Conclusions: Aided by navigation guidance based on O-arm, surgeons can more safely navigate complex anatomy, and more accurately complete the procedure making this technology particularly helpful for pedicle screw fixation. This technique also makes complete avoidance of radiation exposure to surgeons while increasing accuracy and reliability of the surgical procedure for pedicle screw fixation.