High-Fidelity Haptic Rendering for Virtual Drilling on Gradient Porous Bone in Surgery Training

Drilling is an essential procedure in many orthopedic surgeries. Especially in femoral neck fracture surgery, any loss of control can lead to secondary injury to the patient. Consequently, it is imperative for orthopaedists to undergo extensive training to master the appropriate haptic interaction. In this work, a virtual drilling surgery training system with high-fidelity haptic feedback is developed for femoral neck fracture. First, to achieve realistic visual rendering, the external boundary of femur is reconstructed using Triple dexel, allowing for fast and realistic surface reconstruction. Next, the heterogeneous and hierarchical structure of femur is reconstructed using multi-morphology with three periodic minimal surface (TPMS) design approaches. Then, a haptic interaction algorithm based on Triple dexel and TPMS is proposed. This algorithm uses the TPMS equations to quickly compute the densities of the bone chips produced by Triple dexel Boolean operations, thus simulating the variation in porosity at different positions of the bone and providing precise haptic feedback during the drilling process. Finally, a robotic experimental platform is established, and the proposed force model is verified using bovine bones. The results show that the measured values are consistent with the experimental values. Furthermore, evaluation of the training system with medical students as participants shows that a fine haptic rendering improves users' hand-eye coordination skills.