Neuronavigation in the minimally invasive presacral approach for lumbosacral fusion.

Introduction: Intraoperative 3D navigation (3D NAV) is gaining importance in spinal surgery, especially with the advancement of minimally invasive techniques in this field. We hypothesized that 3D NAV may be of benefit in the recently described minimally invasive presacral approach for L4-S1 fusion (AxiaLIF).

Methods: Five patients with refractory low back pain and L5-S1 degenerative disease underwent 3D NAV-assisted placement of a presacral L5-S1 screw. Additionally, a patient recently underwent a two-level AxiaLIF procedure (L4-S1) which was also performed with 3D NAV. Navigation was performed by acquiring intraoperative images via isocentric fluoroscopy and utilizing frameless stereotaxy. Accuracy of 3D NAV was confirmed by overlapping intraoperative images, navigation screenshots, and postoperative CT scans. Outcome was determined by pre- and postoperative VAS (back and leg pain) and ODI.

Results: Operative results were reviewed for all six patients and clinical outcomes were retrospectively reviewed for the five L5-S1 procedure patients. Postoperative imaging demonstrated accurate screw placement in comparison to intraoperative C-arm imaging and navigation imaging in all patients. No perioperative complications were encountered. In the five one-level patients, mean VAS (for back and leg pain) and ODI improved significantly at most recent follow-up.

Conclusion: The minimally invasive presacral approach to L4-L5-S1 fusion can be performed safely and accurately with intraoperative 3D NAV. This is especially the case in two-level AxiaLIF procedures, where computer guidance can provide better planning possibilities for optimal screw trajectory.