PATIENT LEVEL CT CLASSIFICATION AFTER NAVIGATION GUIDED VERSUS FLUOROSCOPY GUIDED PERCUTANEOUS PEDICLE SCREW FIXATION FOR THORACOLUMBAR FRACTURES

Abstract

Thoracolumbar fractures often require posterior stabilization, and the limited exposure in percutaneous fixation makes accurate pedicle screw placement especially important. We compared navigation guided and fluoroscopy guided percutaneous transpedicular fixation in 50 patients with T11-L2 fractures treated at Nishtar Hospital Multan. Adults aged 18-60 years with intact neurology, an AO Spine thoracolumbar injury score above 5, and presentation within 72 hours of injury were included; 25 patients received each approach. The navigation group underwent CT-based trajectory planning with Brainlab, whereas the comparison group underwent placement under anteroposterior and lateral fluoroscopy. Postoperative CT with three dimensional reconstruction was obtained within 24 hours. Our postoperative outcome table recorded an accurate or inaccurate classification for each patient, rather than a grade for every implanted screw. We compared these patient level proportions and examined the baseline and exploratory subgroup counts. The groups had similar mean ages (47.20 ± 9.30 versus 48.76 ± 9.72 years) and body mass indices (28.40 ± 2.61 versus 29.32 ± 2.50 kg/m²). Twenty-four of 25 navigation patients (96%) and 19 of 25 fluoroscopy patients (76%) were classified accurate, an absolute difference of 20.0 percentage points (95% Agresti-Caffo confidence interval, -0.7 to 37.8). The risk ratio was 1.26 (approximate 95% confidence interval, 0.999 to 1.597). Pearson chi-square gave p=0.042; a two-sided Fisher exact test, used because there were only seven inaccurate classifications, gave p=0.098. Navigation was associated with a higher observed patient level classification rate, although the interval was wide and the exact test did not establish a clear difference. Because individual screw counts and CT grades were unavailable, these results do not estimate screw level placement accuracy or clinical safety.