Eye-hand coordination during robotic prostate cancer surgery - how surgical vision reflects on instrument kinematics and vice versa.

During robot-assisted radical prostatectomy (RARP), vision drives the (tele)surgical actions. As such, endoscope movements can be considered a performance-defining parameter during robotic surgery. While instrument kinematics have been the subject of research, it remains unclear how steps in the surgical procedure are reflected in endoscope kinematics, and vice versa. Using the AP4000 mechanical instrument movement recorder, we digitized the x-, y-, and z-trajectories of the endoscope and the 3 robotic arms holding the dissecting instruments and synchronized these data with the endoscopic video feed. To obtain a real-life representation, these evaluations were performed in a clinical pilot setting with one expert surgeon; 4 RARP procedures of which 2 were accompanied by an ICG-fluorescence-guided pelvic lymph node dissection. Perhaps the most obvious endoscope movement observed was related to cleaning. Overall, we found that the step-averaged endoscope kinematic vectors, computed across all standardized features, differed between surgical steps. Hereby endoscope movements coordinated tightly with the activity of the dissecting instruments. The use of fluorescence impacted both endoscope and instrument kinematics. These new insights suggest that endoscopic camera control reflects the dynamics of the surgeon's perceptual demands. In terms of clinical impact, an enhanced understanding of (expert) endoscope use could not only help surgeons better interpret their own actions, but also help optimize training programs aimed at improving surgical proficiency.