Soft tissue navigation for laparoscopic partial nephrectomy

Purpose Minimally invasive surgery of kidney cancer has become a standard therapy method for renal carcinomas. Due to improvements in diagnosis, carcinomas tend to be detected with a smaller size, which often allows for a tissue sparing, laparoscopic partial nephrectomy (LPN). Successful LPN requires a safe resection line inside the kidney, which spares most of healthy tissue, while assuring the complete tumor removal. This paper proposes an approach for a real-time visualization aid during LPN. Methods A surgical soft tissue navigation system for laparoscopic was designed, implemented and tested in vitro. The system enhances the surgeon's perception to provide decision guidance directly before initiation of kidney resection. Preoperative planning, intraoperative imaging, and real-time image processing are incorporated in a system that can enhance an endoscope's image by superimposing relevant medical information like tumor infiltrated tissue and risk structures. This system has a flexible design to facilitate its integration into surgical work flows. The system evaluation was divided into two parts: (1) a virtual evaluation environment, which allows for simulation of all involved system parameters; (2) in vitro surgeries were performed using a laparoscopic training unit to evaluate the overall robustness and accuracy of the navigation system with real data. Results The system was implemented and tested in vitro with favorable results. Real-time video recording of its operation was done to demonstrate the ability to simultaneously visualize the renal collecting system, major blood vessels, and abnormal lesion. Conclusion Laparoscopic partial nephrectomy can benefit from surgical computer assistance with preoperative planning, intraoperative imaging, and real time guidance integrated in a single system. The presented surgical navigation approach is suitable for testing in an intraoperative environment with human patients undergoing LPN.