Vesicular blood flow after ligation of the internal iliac arteries in low anterior resection or abdominoperineal resection

Abstract

PURPOSE: Bilateral ligation of the internal iliac arteries has been reported to be a safe procedure in pelvic surgery because there are five collateral pathways. Some of the five pathways are surgically interrupted after resection of the rectum and two cases in which necrosis developed in the perineum were reported. The aim of the study was to assess the degree of safety and blood flow reducing efficacy of internal iliac artery ligation in rectal cancer surgery. METHODS: The subjects were 23 patients with advanced rectal cancer. Tissue blood flow on the surface of the bladder was measured using a laser Doppler flow meter when unilateral or bilateral internal iliac artery were clamped at a central site or at a peripheral site. RESULTS: Tissue blood flow of the bladder before clamping the internal iliac artery was 6 to 74 ml/min/100 g. Blood flow in the right half of the bladder decreased significantly when the right and both internal iliac arteries were clamped (both,P<0.01), but it did not decrease significantly when only the left internal iliac artery was clamped. The results were the same whether the central site or peripheral site was clamped. When the central site was clamped, there was no difference between the decrease in blood flow in the right half of the bladder whether the right internal iliac artery was clamped or both internal iliac arteries were clamped. By contrast, when the peripheral site was clamped, the decrease in blood flow in the right half of the bladder was much greater when both internal iliac arteries were clamped than when the right internal iliac artery alone was clamped (P<0.01). The results in the left half were the same as in the right half. Blood flow became 33 to 110 (mean, 73; median, 75) percent of the value before clamping when both internal iliac arteries were clamped at the central site, and 18 to 114 (mean, 52; median, 47) percent when both internal iliac arteries were clamped at the peripheral site. No changes in the color of the bladder or other pelvic organs were observed while the internal iliac arteries were clamped. CONCLUSION: Our study suggests that bilateral internal iliac artery ligation causes a temporary decrease in blood flow to the pelvic organs, but the reduction is not great enough to induce necrosis histologically. We recommend the ligation of the internal iliac arteries at the point below the takeoff of the superior gluteal artery to gain a considerable blood flow reducing effect on the pelvic organs.