Marginal artery stump pressure in left colic artery‐preserving rectal cancer surgery: a clinical trial
Excision of the apical lymph node at the root of the inferior mesenteric artery (IMA) is thought to be necessary for radical resection of rectal cancer because apical lymph node resection contributes to improve lymph node retrieval rates and the accuracy of tumour staging.1 Currently, most surgeons perform a high ligation of the IMA in rectal cancer patients to achieve apical lymph node resection, a procedure in which the IMA is ligated at its origin and the blood supply to the distal colon depends completely on the marginal artery that arises from the middle colic artery. Although it is thought that the marginal artery is adequate for sustaining the viability of the remaining colon,2 some studies have shown that a high tie of the IMA significantly reduces perfusion of the proximal limb.4 Furthermore, the resulting inadequate collateral circulation may also lead to severe colonic ischaemia in some patients.8 It has been proposed that low ligation, which is defined as ligation below the origin of the left colic artery (LCA) might solve this problem.7 However, this alternative procedure may result in decreasing the number of harvested lymph nodes and influencing lymph node staging, thereby affecting post‐operative treatment. In addition, skip metastases may also occur in some patients. In view of these concerns, it was recently proposed that lymph node dissection around the IMA with preservation of the LCA would yield superior results.9 Theoretically, this surgical method would offer a better anastomotic blood supply and ensure adequate lymph node retrieval rates. Studies testing this hypothesis in practice are conspicuously lacking but are urgently needed to advance the field.
The mean inferior mesenteric artery stump pressure has been used to evaluate the viability of the colon after aortic reconstruction in some studies,11 but marginal artery stump pressure (MASP) measured after colon and artery reconstruction in colorectal surgery can provide a more accurate measure of the blood supply to the distal colon. The purpose of this study was to identify predictive factors that may influence vascular perfusion of the anastomosis and to simultaneously evaluate the effects of high or low ligation of the IMA on the anastomotic blood supply, lymph node retrieval rate and operation time.