The effects of real-time image navigation in operative liver surgery

Purpose: In liver surgery, preoperative planning is usually performed by using CT scans. Ultrasonic probes are frequently used operatively to verify tissue deformations, for example when resecting a liver tumor with an ultrasonic dissector. Avoidance of dissecting vitally important hepatic vessels and the recrudescence of tumors are of crucial importance. The potential benefits of real-time image navigation in operative liver surgery were investigated experimentally. Methods: Four model tumors with realistic ultrasonic features have been embedded into a bowl filled with candle gel. The aim was to locate these tumors with the ultrasonic probe and to puncture them safely with the ultrasonic dissector. The experiment was performed four times, once completely without navigation and three times with ultrasonic-based navigation but under different preconditions. Results: Less attempts are needed to puncture a certain tumor with real-time image navigation than without navigation (P<0.02%). The effectiveness of ultrasonic-based navigation varied with the surgical preconditions. Conclusions: The use of a suitable navigation system improves safety and effectiveness in liver surgery for intraoperative localization of key structures such as tumors. However, resecting hepatic tumors with appropriate safety margin demands for further enhancements concerning the proposed methods.