Development and Improvement of Real-Time Navigation System for Laparoscopic Hepatectomy

Abstract

Introduction: We are going to try development of real-time navigation system for laparoscopic hepatectomy, which resembles a car navigation system. We report our real-time navigation system and surgical procedure. Methods: Virtual images are reconstructed using “New-VES” system developed by Nagoya University Graduate School of Information Science. These images correspond to maps of car navigation system. Some of patient's body parts are registered in virtual images using a magnetic position sensor. Patient's body after registration corresponds to The Earth. A transmitter for magnetic position sensor, which corresponds to an artificial satellite, is placed about 30cm above patient's body. A micro magnetic sensor, which corresponds to GPS antenna, fixes on the handling part of laparoscope.Fiducial registration error (FRE) is utilized to evaluate accuracy of real-time navigation system. Results: We performed laparoscopic hepatectomy using this system in 21 patients. Mean FRE of initial 5 patients was 17.7mm. First improvement was that MDCT were taken using radiological markers for registration of body parts. Mean FRE of the 8 patients who utilized first improvement was 10.2mm and decreased (p = 0.014). Second improvement was that a micro magnetic sensor as an intraoperative body position sensor was fixed on the right-sided chest wall and meant that pre- and post- operative FRE was similar due to an intraoperatively automatic correction of gap of body position. Preoperative and postoperative mean FRE of the 8 patients who utilized second improvement were 11.1mm and 10.1mm (p = 0.250). Conclusions: Our real-time navigation system can assist laparoscopic hepatectomy.