Bipolar coagulation at different energy levels: effect on patency

Determining the extent of damage caused by bipolar coagulation at different levels is critical in microsurgery. If no significant damage occurs at known levels, this technique can be used instead of ligation, saving considerable time. One hundred eighty Sprague-Dawley rats were divided into six groups of 30 each. The effects of bipolar coagulation were assessed at either 2 or 10.4 watts at the junction between the common femoral artery and a branch vessel. Three common clinical settings were used: branch coagulation without interruption of blood flow in the common femoral artery; branch coagulation with interruption of blood flow for 30 minutes; and branch coagulation with arterial anastomosis 3-5 mm distal to the branch. Control procedures without coagulation were performed on the contralateral vessels. The animals were re-explored at 5-7 days. No differences occurred in patency of the coagulated vessels at 2 or 10.4 watts of delivered energy as compared with controls. Recanalization of the side branch occurred in approximately 80% (144/180) of specimens. Extensive damage to endothelium, tunica intima, and tunica media occurred for 1-2 mm around the site of the coagulated branch. The forceps pick-up test demonstrated little difference in flow of the cauterized vessel compared with controls. However, the cauterized vessel had a clinically weaker pulse stream of the transected common femoral artery. Recanalization of the coagulated side branch commonly occurred with a fibrin cap at the end of the vessel. Manipulation of the branch vessel frequently caused rebleeding. Our study shows that bipolar coagulation can be used effectively if coagulation is located at least 2 mm from the main vessel.