Development of the Endo-Periscope for Improvement of Depth Perception in Laparoscopic Surgery

Abstract

Abstract 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 light source of the endoscope forms a ring around the camera lens, and the endoscope movements are limited by the incision point. The absence of shadows in the camera picture and the restricted ability to observe organs from aside complicate the surgeon’s depth perception. This paper describes the development of a new steerable endoscope that is 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. The endoscope, which is called Endo-Periscope, uses a new spatial parallelogram-mechanism to transform the movements of the handgrip into movements of the steerable tip. The handgrip contains an arrow that points always in the direction of the line-of-sight of the tip-camera. This provides intuitive control of the tip and it shows the surgeon how the camera is oriented in the abdominal cavity. The light source is located on the shaft and the tip-camera can be moved in six degrees of freedom. This enables the surgeon to observe organs from different sides and to use shadows as a depth information source. Part of the parallelogram-mechanism is a new kind of spring which combines a very high torsional stiffness with a low, asymmetric bending stiffness. The spring and the working principle of the Endo-Periscope have been applied for two patents.