Augmented Reality Navigation for Spinal Pedicle Screw Instrumentation using Intraoperative 3D Imaging

Background context

Due to recent developments in augmented reality with head-mounted devices, holograms of a surgical plan can be displayed directly in the surgeon’s field of view. To the best of our knowledge, 3D intraoperative fluoroscopy has not been explored for the use with holographic navigation by head-mounted devices in spine surgery.

Purpose

To evaluate the surgical accuracy of holographic pedicle screw navigation by head-mounted device using 3D intraoperative fluoroscopy.

Study design

In this experimental cadaver study, the accuracy of surgical navigation using a head-mounted device was compared to navigation with a state-of-the-art pose-tracking system.

Methods

Three lumbar cadaver spines were embedded in non-transparent agar gel, leaving only commonly visible anatomy in sight. Intraoperative registration of preoperative planning was achieved by 3D fluoroscopy and fiducial markers attached to lumbar vertebrae. Trackable custom-made drill sleeve guides enabled real-time navigation. In total, 20 K-wires were navigated into lumbar pedicles using AR-navigation, 10 K-wires by the state-of-the-art pose-tracking system. 3D models obtained from post-experimental CT scans were used to measure surgical accuracy. MF is founder and shareholder of Incremed AG, a Balgrist University Hospital start-up focusing on the development of innovative techniques for surgical executions. The other authors declare no conflict of interest concerning the contents of this study. No external funding was received for this study.

Results

No significant difference in accuracy was measured between AR-navigated drillings and the gold standard with pose-tracking system with mean translational errors between entry points (3D vector distance; p = 0.85) of 3.4 ± 1.6 mm compared to 3.2 ± 2.0 mm, and mean angular errors between trajectories (3D angle; p = 0.30) of 4.3 ± 2.3° compared to 3.5 ± 1.4°.

Conclusion

In conclusion, holographic navigation by use of a head-mounted device achieves an accuracy comparable to the gold standard of high-end pose-tracking systems.

Clinical significance

These promising results could result in a new way of surgical navigation with minimal infrastructural requirements but now have to be confirmed in clinical studies.