Evaluation of efficacy of an ultrasonic scalpel for pulmonary vascular ligation in an animal model

Objective: Dissection to accommodate bulky stapling devices may cause injury to pulmonary arteries in thoracoscopic lobectomies. The Harmonic Ace (Ethicon Endo-Surgery, Inc; Cincinnati, Ohio), a small ultrasonic scalpel used in systemic vessels, was tested on pulmonary vessels in pigs. Methods: Nine pigs were assigned 1- or 6-week survival. Lobectomies were performed using the device to divide and ligate pulmonary vessels. Vessel diameter was measured, and ligation outcome was recorded. Necropsies were then performed. Results: Permanent ligation occurred in 76% of arteries and 92% of veins. At the highest power setting, the instrument showed no failure in arteries 5 mm or less and veins 7 mm or less. Necropsies revealed no evidence of postoperative bleeding. Histopathologic analysis revealed acute coagulation necrosis at 1 week. By 6 weeks, the vessel stumps displayed features consistent with normal wound healing. Conclusions: This device reliably divides pulmonary vessels 4 mm and smaller, typically encountered in pig lobectomies. Higher power settings and operator experience may increase effectiveness. Further testing is necessary to delineate the device's limitations before potential use in human pulmonary vasculature.