Real-Time Optimization-Based Tracking Method for Active Optical Navigation in Orthopedic Surgeries: An Experimental Study

Optical tracking system (OTS) plays a significant role in orthopedic surgeries to track the relative position and orientation between the surgical tool and the patient's lesion via markers. Typically, OTS is placed in a fixed pose and remains static throughout the surgery. However, the measurement volume (MV) of OTS is limited. With the movements of the surgical tool or the patient, the markers might move beyond the MV, causing navigation failure. To address this challenge, this paper proposes a real-time optimization-based tracking method to actively adjust the observation view of the OTS and guarantee the consistency of intraoperative navigation. Specifically, the continuously tracking of markers is formulated into an optimization problem, where minimum and maximum angle optimization functions are designed to ensure surgical safety. The dynamic accuracy of the OTS is also evaluated to be reliable during the adjusting process. Ultimately, simulations and phantom experiments are performed on an active navigation system to verify the effectiveness of the proposed optimization tracking method. Experimental results show that the OTS can always track all markers when confronted with moving markers. The navigation robot successfully keeps the markers within the MV of the OTS.