Redefining the collateral system between the superior mesenteric artery and inferior mesenteric artery: a novel classification

Total mesorectal excision (TME) as proposed by R.J. Heald more than 20 years ago, is nowadays accepted worldwide for optimal rectal cancer surgery. This technique is focused on an intact package of the tumour and its main lymphatic drainage. This concept can be translated into colon cancer surgery, as the mesorectum is only part of the mesenteric planes which cover the colon and its lymphatic drainage like envelopes. According to the concept of TME for rectal cancer, we perform a concept of complete mesocolic excision (CME) for colonic cancer. This technique aims at the separation of the mesocolic from the parietal plane and true central ligation of the supplying arteries and draining veins right at their roots. Prospectively obtained data from 1329 consecutive patients of our department with RO-resection of colon cancer between 1978 and 2002 were analysed. Patient data of three subdivided time periods were compared. By consequent application of the procedure of CME, we were able to reduce local 5-year recurrence rates in colon cancer from 6.5% in the period from 1978 to 1984 to 3.6% in 1995 to 2002. In the same period, the cancer related 5-year survival rates in patients resected for cure increased from 82.1% to 89.1%. The technique of CME in colon cancer surgery aims at a specimen with intact layers and a maximum of lymphnode harvest. This is translated into lower local recurrence rates and better overall survival.

The aim of this study is to evaluate the influence of dividing the inferior mesenteric artery (IMA) and preserving the left colic artery (LCA) on rectosigmoid cancer surgery. Colonic blood flow at the proximal site of the anastomosis was measured by laser Doppler flowmetry in 96 patients with cancer of the rectum and sigmoid colon while clamping IMA or LCA. Results were analyzed with patient characteristics and postoperative complications. Blood flow was significantly decreased by either IMA or LCA clamping, and its reduction rate was 38.5 +/- 1.8%, ranged from 0 to 82.8%, or 16.4 +/- 1.8%, ranged from 0 to 66.2%, respectively. For multivariate analyses, aging and male gender were predictive factors of high blood flow reduction by IMA clamping. The reduction rate was significantly correlated with aging in male patients, while no such correlation was observed in women. Aging correlation in men was more significant in ultralow anterior resection cases. Three elderly male patients received IMA high ligation among 19 patients who demonstrated more than 50% blood flow reduction by IMA clamping. Among these, two patients, those who underwent ultralow anterior resection, suffered severe anastomotic ischemia. Colonic blood flow at the proximal site of the anastomosis was significantly decreased by either IMA or LCA clamping. Patients with high reduction by IMA clamping need intraoperative efforts to prevent anastomotic ischemia, particularly in elderly male patients who undergo ultralow anterior resection.