Experimental comparison of kinematics and control interfaces for laparoscope positioners

Ergonomics is known to be poor during laparoscopic surgery because of the minimal access and the manual handling of the laparoscope, which is required to display intra-abdominal images on monitors in the absence of direct vision. Several robots were developed over the last two decades to hold and move the laparoscope, so as to offer better image stability and free the assistant’s hands and mind. The purpose of this study is to compare the motion performance of these devices, including the EVOLAP robot designed at UCL, and to assess the influence of two main factors on motion duration: the kinematic architecture and the control capabilities of the human-robot interface (i.e. the number of directions). An experimental bench was set up using a modified version of the EVOLAP robot, capable of generating laparoscope motions identical to the ones induced by the three most common kinematics among existing laparoscope positioners. Results show that the kinematics has a large influence on motion duration. It also appears that performance is increased significantly with a control interface that provides more motion directions that the commercially available ones.