Methodology for Haptic Modeling of Trocar Insertion Procedure

Abstract

Trocar insertion is the first step in laparoscopic surgery procedures. It is a difficult procedure to learn and practice because it is carried out almost entirely without any visual feedback of the organs underlying the tissues being punctured. A majority of injuries are attributed to excessive use of force by surgeons. So there is a need for a haptic based computer simulator to train and improve the trocar insertion skills. In this paper, a new methodology for the modeling of trocar insertion is proposed. First, trocar insertion data (force/torque, displacement, etc.) are collected from animal models. Based on this data, a material model is computed using a hyper-elastic finite element computation (FEM). Using the FEM model, tissue deformation of the abdominal wall is calculated off-line for various conditions of tissue puncture. Deformation data are used to train a neural network which is, in turn, used to compute a real time virtual trocar insertion simulation. Force feedback is also modeled based on clinical data and is integrated into the simulator. This novel method allows for precise trocar insertion simulation based on prior FEM offline computation. The proposed system was implemented in a laboratory environment.