Theoretical background and conceptual solution for depth perception and eye-hand coordination problems in laparoscopic surgery

The indirect method of observation and manipulation in laparoscopic surgery complicates the surgeon's depth perception and impairs his/her eye-hand coordination. Depth perception problems are due to misfits in accommodation and convergence, absence of shadows in endoscopic camera pictures and absence of stereo-vision and movement parallax. Eye-hand coordination problems are caused by the distant location of the monitor and by the fact that the surgeon's hand movements are rotated, mirrored and amplified when they appear on the monitor These effects are very confusing, especially for trainee laparoscopic surgeons and require a long and intensive training period to overcome. This paper gives a theoretical background of the depth perception and eye-hand coordination problems. A technical concept of an endoscope positioning system is described that compensates misorientations by using a flexible 90 degrees endoscope. Movement parallax is achieved using a motorised endoscope positioner controlled by the surgeon's head movements.