Comparing the Safety and Efficacy of 3D Navigation vs. Fluoroscopy in Endoscopic Transforaminal Discectomy

Introduction: Endoscopic spine surgery traditionally uses fluoroscopic guidance for targeting and initial docking. In endoscopic transforaminal approaches, fluoroscopic targeting of small areas is limited by coarse anatomic detail in cases with complex anatomy and a small margin-of-safety due to the exiting nerve root. To address this, 3D-navigation provides real-time guidance with accurate image registration. In this study, we compare the safety and efficacy of fluoroscopic vs. navigated transforaminal discectomies.

Methods: A retrospective review was conducted of 27 patients who underwent thoracic or lumbar transforaminal discectomy at a tertiary academic hospital from 2021-2023. Seven navigated cases were done, all with the Medtronic O-arm. Patient radiation exposure was measured via cumulative air kerma (CAK), dose area product (DAP), and effective dose. Changes in validated pain metrics (VAS and ODI) were recorded at 1-month and > 3-month postop.

Results: Total effective-radiation dose (14.2 +/- 8.8 vs. 2.0 +/- 2.7 mSV; p< 0.001) was higher with navigation. Localized radiation was expectedly reduced with lower CAK (8.4 +/- 10.2 vs. 39.0 +/- 30.2 mGy; p=0.02) and DAP (1.9 +/- 2.3 vs. 8.7 +/- 6.4 Gy*cm2; p=0.02). Efficient targeting with navigation was displayed with similar operative time (215.6 +/- 62.5 vs. 206.2 +/- 76.7 minutes, p=0.77) despite initial time to register. Clinically, patients experienced significantly greater pain relief 1-month after navigation vs. fluoroscopy with improved VAS (-5.8 +/- 1.0 vs. -2.3 +/- 2.9; p=0.04) and ODI (- 15.3 +/- 3.1 vs. - 14.4 +/- 17.7; p=0.93). Although nonsignificant, relief was sustained at > 3 months (VAS - 4.5 +/- 3.5 vs. - 2.0 +/- 2.0; p=0.37).

Conclusion : While global radiation exposure is higher with navigation, this is balanced with expedited targeting which offsets the upfront time needed to acquire the intraoperative CT and register. Furthermore, navigation guides complete decompression and helps increase the chance of significant improvements in clinical outcomes.