O2085: For an Experienced Surgeon, Using Intraoperative Ct-based Pedicle Screw Navigation in Pediatric Spine Deformity Has Minimal Impact on Screw Accuracy, but Is Associated with Increased Operative Time and Radiation Exposure

Background: Intraoperative CT guided navigation provides a dual benefit of enabling navigation-guided screw insertion and post-insertion accuracy assessment. Implementing this technique requires alterations to the surgical workflow, which may lead to longer surgery time, increased blood loss, and radiation.

Methods: This study compared pediatric spine deformity patients who underwent surgery using intraoperative CT navigation to those who underwent deformity surgery using the free hand technique. In the navigation group, a reference frame was applied to the caudad spinous process after exposure, and a CT spine was performed at a dose of 50-70% of the recommended pediatric dose per the manufacturer. A scan was carried out after all screw insertions to confirm screw accuracy at a lower dose than the first, and a repeat scan was performed if there were concerns about reference frame displacement or navigation accuracy. In the free hand technique, fluoroscopy was used to confirm levels, shoulder balance post-correction, and sometimes to assist with screw insertion. Demographic, radiographic, radiation exposure, and perioperative data were collected and analyzed using Kruskal-Wallis and Fisher’s exact tests.

Results: 112 AIRO navigation patients were compared to 421 AIS patients with pedicle screws placed freehand and confirmed on fluoroscopy. The patients in both groups were similar in terms of age, BMI, preoperative Cobb, and preoperative kyphosis (p > 0.05). Postoperative Cobb, kyphosis, and overall Cobb correction were similar. Blood loss was similar between the groups. Patients in the navigation group had significantly longer surgical and anesthesia times despite having a similar number of fixation points and fused levels. Additionally, radiation exposure was higher in the navigation group. The length of stay was similar between the patients (p > 0.05), and there were no significant differences in postoperative complications, infection rate, or 30-day return to the emergency department. In 20 patients, more than two scans had to be performed as the accuracy was lost during surgery. In 153 navigation patients, most screws were initially inserted freehand and then checked for placement with an intraoperative CT scan. 3 screws required slight backing off, as the tip was protruding anteriorly by less than 4mm. In the free hand group, screw accuracy was confirmed on postoperative radiographs. No screws in either group required revision. The use of navigation equipment, prolonged operating room time, and need for a CT technician contributed to the increased cost in the navigation group.

Conclusion: The study suggests that there is no significant increase in safety or screw precision when using navigation for pedicle screw placement in pediatric spine deformity surgery. On the other hand, there is a drawback of significantly longer anesthesia and surgery times, as well as increased radiation exposure. However, the availability of navigation presents a potential benefit of "peace of mind" in surgical practice.