A Circular Needle Path Planning Method for Suturing in Laparoscopic Surgery

The work presented in this paper addresses the problem of the stitching task in laparoscopic surgery using a circular needle and a conventional 4 DOFs needle-holder. This task is particularly difficult for the surgeons because of the kinematics constraints introduced by the trocar. So as to assist the surgeons, we propose to compute possible pathes for the needle through the tissues, which limits as much as possible tissues deformations while driving the needle towards the desired target. The article proposes a kinematic analysis and a geometric modeling of the stitching task. Based on this, some simple but useful information can be obtained to help the surgeon. The description of the task with well-chosen state variables allows to simply express the path planning problem. Conditions for the existence of acceptable pathes are given and a method to compute possible pathes is presented. Resulting pathes are shown to be satisfactory even under awkward configurations.