Experimental study of survival of arterialized venous flap

ABSTRACT

To increase the survival area of the venous flap, we studied the arterialized venous flap in a rabbit ear model. The ears of 12 New Zealand white rabbits(n=24) were randomized into three groups, group A receiving arterio-venous anastomosis 14 days before the arterialized venous flap elevation; group B receiving bipedicled flap elevation 14 days before arterialized venous flap elevation; group C receiving no pretreatment before the arterialized venous flap elevation. Tc -pertechnetate scan was performed on all groups immediately after the arterialized venous flap elevation to evaluate the blood flow of the flap. The survival area of the flap was measured 14 days after the arterialized venous flap elevation. Average ratio of survival area was 92% in Group A, 88% in group B, which were comparatively higher than the 12% in group C. The entire flap was visualized in groups A and B on scan images, however, only the proximal area of the anterior and posterior marginal vein was visualized in group C. Flap survival pattern was similar to that of the scan image and the slope of time-activity curve of groups A and B was much steeper than that of group C. High survival rate of group A, which received the arterio-venous anastomosis as a pretreatment, may be due to the decrease of resistance of outflow during the 14 days. Anticipated mechanisms involved are, valve insufficiency due to high pressure arterial inflow, development of vascular collaterals in the flap, and opening of arteriovenous(A-V) shunt. Bipedicled flap elevation as a pretreatment may not effect on valves, however, may impair the sympathetic nerve and cause ischmic stimuli which in turn may develop vascular collaterals and make an opening of the A-V shunt.