Optimization-Based Tracking Method for Active Navigation in Orthopedic Surgeries

Intraoperative optical tracking system (OTS) plays an essential role to measure the position and orientation of the surgical tools via passive tools during surgery operations. Due to the limited measurement volume (MV), the tracked tools might probably move out of the MV during the surgery, causing navigation failure. In addition, the accuracy of the OTS is influenced by several factors, i.e., working distance and the relative orientation of the tracked tool. If the surgical tool is near the border of the MV, the tracking accuracy may degrade and the risk of a missing tool also increases. To address this challenge, this paper proposes an active navigation system where a navigation robot is utilized to adjust the pose of the OTS such that the tracked tools are kept near the center of the MV, maintaining the tracking accuracy. A distance margin is proposed to quantify the degree of danger of losing the tracked tools. Subsequently, a real-time optimization tracking method is formulated to plan the next pose of the OTS until the distance margin is lower than the threshold. Ultimately, abundant simulations are performed on an active navigation system to demonstrate the effectiveness of the proposed optimization tracking method.