Evaluation of Virtual Shadow's Direction in Laparoscopic Surgery

Laparoscopic surgery can realize minimal invasive surgery. However, it's difficult for surgeon to recognize the depth during suturing. Binocular endoscope helps surgeons to recognize the depth, but surgeons do not understand the circumstance by equipping with head mounted display. Since shadow helps surgeon to recognize the depth, in this paper, we developed the virtual shadow drawing system. The system shows shadow like actual by the estimation of the forceps position, surface shape and shadow's position. We tested the accuracy of the system by evaluating the estimated distance and angle between the forceps and the surface. The error and delay were enough small to draw shadow like actual. Furthermore, participants performed the suturing task while looking at the shadow. The experiment was carried out in a variety of the shadow's direction. As result, the suturing error's mean and variance value was the least at the 270 deg. In conclusion, the appropriate shadow would be vertical to the wounds.