Histopathological Changes of the Renal Arterial Wall After Bipolar Coagulation in Experimental Rat Models

ABSTRACT

The bipolar coagulator has been frequently used in reducing the size of aneurismal neck or dissecting the aneurismal sac. However the effects of bipolar current on the wall of vessels have not been adequately documented. The author studied the histopathological changes of the renal arterial wall after bipolar coagulation. Thirty one Sprague-Dawley strain rats of both sexes and of various age were used. Under penthobarbital anesthesia, the left renal artery was coagulated with bipolar forcep just distal to it's origin from the aorta. The rats were divided into two groupsGroup A was coagulated for two secondsGroup B for one second. The coagulation sites of vessels were examined grossly and microscopically in three and six months, respectively. The results were summarized as followings 1) In both three and six months groupsthe internal elastic membrane and elastic fibers were destructed, fragmented and thinned;the medial smooth muscle cells were damaged and decreased in number. 2) While the endothelial cells were severely desquamated and scattered in three months group, but there was an evidence of partial regeneration of endothelium and reduction of inflammatory reaction in six months group. Fibrosis was more augmented in six month group than three month group. 3) Between group A and B, There weemed to be no definite discrepancy in histopathological findings. 4) Pseudoaneurysms were developed in 72.2% of three months group and in 61.5% of six months group, but there was no significant statistical difference in the rate of pseudoaneurysm formation between the two groups(p>0.05, chi2=0.393). 5) Above findings suggest that the pseudoaneurysm which might be produced by bipolar coagulation of vessels in the neurosurgical operation, would be progressed to the true aneurysm if continuous hemodynamic factors are exerted upon the pseudoaneurysm. Therefore, it is desirable that the bipolar current should be used very catiously during the surgery of cerebrovascular disease.