Computer Navigated Spinal Surgery Using Magnetic Resonance Imaging and Augmented Reality

Abstract Current spinal pain management procedures, such as radio frequency ablation (RFA) and epidural steroid injection (ESI), rely on fluoroscopy for needle placement which exposes patients and physicians to ionizing radiation. In this paper, we investigate a radiation-free surgical navigation system for spinal pain management procedures that combines magnetic resonance imaging (MRI) with fiducial ArUco marker-based augmented reality (AR) to serve as a radiation-free alternative. High-resolution MRI scans of a lumbar spinal phantom were obtained and assembled as a surface mesh. Laplacian smoothing algorithms were then applied to smoothen the surface and improve the model fidelity. A commercially available stereo camera (ZED2) was used to track single or dual fiducial ArUco markers on the patient to determine the patient's real-time pose. Custom AR software was applied to overlay the MRI image onto the patient, allowing the physician to see not only the outer surface of the patient but also the complete anatomy of the patient below the surface. Needle-insertion trials on a 3D-printed three-vertebra phantom showed that dual ArUco marker tracking increased the accuracy of needle insertions and reduced the average needle misplacement distance compared to single ArUco marker procedures. The average needle misplacement is comparable to the average deviation of 2 mm for conventional epidural techniques using fluoroscopy. Our radiation-free system demonstrates promise to serve as an alternative to fluoroscopy by improving image-guided spinal navigation.