The Angiographic Anatomy of the Small Arteries and Their Collaterals in Colorectal Resections Some Insights Into Anastomotic Perfusion

Objective: The aim of this study was to examine by screening angiography the anatomy of the small arteries and their collaterals in colorectal resections in order to identify factors that might be implicated in anastomotic leak. Summary Background Data: Anastomotic leak is more frequent following low anterior resection. Vascular compromise is frequently implicated but poorly understood as a mechanism. Methods: High definition screening angiography was performed on 17 colorectal resection specimens. Results: (1) The small arteries of the colon (the vasa recta that arise from the marginal artery) show variability in their spacing and in their collaterals based on their anatomical positions. At the splenic flexure and the proximal and mid descending colons, the vasa recta are spaced 2-cm apart and have few collaterals. At the right, transverse, distal descending and sigmoid colons, the vasa recta are spaced <1 cm apart and have more extensive collaterals. (2) The small arteries of the rectum are spaced <1 cm apart and also show variability in their collaterals based on their anatomical level. In the mid-to-upper rectum there are good collaterals between the small arteries within the mesorectum based upon the bifurcation of the superior rectal artery and its main branches. In the lower rectum, however, there are only a few and very variable intramural collaterals between the small arteries. Conclusions: Based on these findings, unrecognized disruption of small artery collaterals during colorectal resection might be implicated in anastomotic leak and in particular might explain the higher leak rate in low anterior resection.