Automatic Surgical Field of View Control in Robot-Assisted Nasal Surgery

In endoscopic nasal surgery, robots, rather than surgical assistants, can be introduced to hold endoscopes and act as the surgeon's third hand, which helps to reduce their operation burden. To address the problem of robot-assisted surgical field of view (FOV) acquisition in endoscopic nasal surgery, this letter proposes an automatic surgical FOV control method based on tracking motion for the entire surgical process to achieve efficient and safe surgical FOV acquisition. First, through the analysis of the spatial pose relationship between the nasal endoscope and the surgical instrument, the desired endoscope pose corresponding to the optimal surgical FOV during surgery is obtained. Then, an automatic surgical FOV control method based on tracking motion is proposed. For automatic FOV acquisition outside the nasal cavity, an unconstrained tracking motion control strategy is proposed. For automatic FOV acquisition inside the nasal cavity, a remote center of motion (RCM) constrained control strategy is proposed. Combined with the entire surgical process, the overall control framework of the surgical FOV during nasal surgery is established. After that, a virtual fixtures (VFs) model based on the CT data of the nasal cavity and a safety contact force threshold control method are proposed to improve the safety of robot motion. Finally, the robot-assisted maxillary sinus surgery experiment is carried out. The results show that the proposed automatic FOV control method can realize clear and safe automatic FOV acquisition during the entire surgical process so that the surgeon can realize the "one surgeon three hands" operation, which reduces the surgeon's operation burden.