A multi-view interactive virtual-physical registration method for mixed reality based surgical navigation in pelvic and acetabular fracture fixation

Purpose: The treatment of pelvic and acetabular fractures remains technically demanding, and traditional surgical navigation systems suffer from the hand–eye mis-coordination. This paper describes a multi-view interactive virtual-physical registration method to enhance the surgeon’s depth perception and a mixed reality (MR)-based surgical navigation system for pelvic and acetabular fracture fixation. Methods: First, the pelvic structure is reconstructed by segmentation in a preoperative CT scan, and an insertion path for the percutaneous LC-II screw is computed. A custom hand-held registration cube is used for virtual-physical registration. Three strategies are proposed to improve the surgeon’s depth perception: vertices alignment, tremble compensation and multi-view averaging. During navigation, distance and angular deviation visual cues are updated to help the surgeon with the guide wire insertion. The methods have been integrated into an MR module in a surgical navigation system. Results: Phantom experiments were conducted. Ablation experimental results demonstrated the effectiveness of each strategy in the virtual-physical registration method. The proposed method achieved the best accuracy in comparison with related works. For percutaneous guide wire placement, our system achieved a mean bony entry point error of 2.76 ± 1.31 mm, a mean bony exit point error of 4.13 ± 1.74 mm, and a mean angular deviation of 3.04 ± 1.22°. Conclusions: The proposed method can improve the virtual-physical fusion accuracy. The developed MR-based surgical navigation system has clinical application potential. Cadaver and clinical experiments will be conducted in future.