Development of Steerable Endoscopes to Improve Depth Perception During Laparoscopic Surgery

Laparoscopic surgery is carried out by using an endoscope with a camera that is inserted through a small incision in the abdominal wall. The camera pictures are presented on a monitor. The movements of the endoscope are limited by the incision point. This results in a restricted ability to observe organs from different sides, which complicates the surgeon’s depth perception. This paper describes the development of two new steerable endoscopes that are the product of a close co-operation between the Man-Machine Systems Group of the Delft University of Technology and the Hirose & Yoneda Laboratory of the Tokyo Institute of Technology. Both endoscopes contain a new spatial parallelogram-mechanism to transform the handgrip movements into movements of the steerable tip. The handgrips contain an arrow that points always in the direction of the line-of-sight of the tip-camera. This provides intuitive control of the tip, showing how the camera is oriented in the abdominal cavity. The tip-cameras can be moved in six degrees of freedom, thus enabling the surgeon to observe organs from different sides. Part of the parallelogram-mechanism is a new kind of spring that combines high torsion stiffness with a low, asymmetric bending stiffness. The endoscopes and the spring have been applied for two international patents.