Ultrasonic scalpel for sealing of the thoracic duct: evaluation of effectiveness in an animal model.

To verify the usefulness of an ultrasonic scalpel for the sealing of lymphatic ducts, a Harmonic Ace scalpel (Ethicon Endo-Surgery, Inc, Cincinnati, OH) was tested, using the thoracic ducts in pigs. Indocyanine green was injected into the abdominal lymphatic ducts in two pigs, and the stained thoracic ducts were identified. The thoracic ducts were then divided and sealed into seven sections with a Harmonic Ace scalpel, used at a power setting of level 3. The cut ends of the thoracic ducts were evaluated macroscopically, histologically, and by measuring bursting pressure. The whole length of thoracic duct of each pig was clearly imaged by pigment. Each stump divided by the ultrasonic scalpel was completely sealed, and there was no pigment leakage from the cut end macroscopically. Histologic examination revealed that the cut end was sealed by homogenous degenerative coagulation. Bursting pressures could be determined at three cut ends of thoracic ducts and were 195 mmHg, 188 mmHg, and 203 mmHg, respectively. The thoracic ducts were reliably divided and sealed by an ultrasonic scalpel in pigs. This device is expected to be a useful tool for the surgical treatment of chylothorax.