Microwave energy as a precoagulative device to assist in hepatic resection

Microwave energy is another energy source than can be used to precoagulate hepatic tissue during hepatic resection. The aim of this study was to develop an optimal microwave precoagulation technique in a porcine model and then validate the technique during hepatic resection in patients.

Institutional Animal Care and Use and Institutional Review Board (IRB)-approved protocols were utilized for hepatic resection in a porcine model and validation in patients using microwave energy for precoagulation. Different numbers of antennas (one, two or three; spaced 5 mm apart) and ablation times (20, 30, 40, and 60 s) were evaluated to identify an optimal technique that effectively provided precoagulation.

Animal studies: Two antennas for 30 s provided the optimal ablation time, ablation width, mean size of largest vessel coagulated, and minimal bleeding when compared with other techniques. However, given that this is not an optimal technique for laparoscopic precoagulation, one antenna for 60 s was found to provide similar precoagulation success. Patient validation: To validate these techniques, three patients underwent open hepatectomy using two antennas with 5 mm spacing for 30 s, demonstrating successful precoagulation up to inflow/outflow vessels of 10 mm size or greater, which were controlled with a vascular stapler. In addition three patients underwent laparoscopic hepatectomy using one antenna for 60 s and demonstrated successful precoagulation up to inflow/outflow vessels of 8 mm or greater, which were controlled with a vascular stapler.

Microwave energy is a safe and effective precoagulation device to achieve good hemostasis during hepatic resection with both open and laparoscopic technique.