Modeling patients for optimized port placement in robot-assisted surgery

Robot-assisted laparoscopic surgery is gaining popularity because it has been shown to improve accuracy, reduce errors, and assists surgeons in performing more difficult procedures. However, positioning the ports and posing the robot arms to be able to perform the intervention while avoiding tool or arm collisions can be a lengthy and difficult process. The aim of this project was to design a decision aid for patient-specific, optimal port placement in pre-operative planning. This paper presents the analysis and design methods, including the building of separate patient and robot models. Based on a requirements analysis, a symbolic model of the robot was created based on the da Vinci Si Surgical System using the modified Denavit-Hartenberg (DH) parameters to define its work volume. Data from anthropometric tables and patients undergoing laparoscopic procedures were collected to create a library of realistic patient models. These two models, combined in a 3D interactive virtual environment, allow selection of suitable port locations, and a pose and position plan for the robotic arms with unrestricted access to the target area while avoiding collisions between instruments and other objects in the operating room. A simple and elegant protocol was then designed to collect actual patient data for validation of the models. Once validated, this model can be used for any robotic procedure within the abdomen.