ULCERATION OF THE ILEUM IN CROHNS-DISEASE - CORRELATION WITH VASCULARANATOMY

Background - Ileal ulcers in Crohn's disease tend to lie along the sam e side of the bowel wall as the mesenteric attachment; the mesenteric and antimesenteric borders are supplied by short and long arteries,res pectively. Aim - To examine the localisation of ileal Crohn's ulcers a nd to test the hypothesis that predilection of Crohn's ulcers for the heal mesenteric margin is explained by the existence of end arteries t hat supply the mesenteric margin. Methods The localisation of ulcers i n the bowel wall was examined in eight resection specimens of Crohn's disease of the terminal ileum. The vascular anatomy of normal terminal ileum (n = 8) and proximal jejunum (n = 8) postmortem specimens was s tudied; isolated long and short vessels were Ligated before perfusion in four of these specimens. Results - All eight specimens of Crohn's d isease of the terminal ileum showed longitudinal ulceration along the mesenteric margin. In the postmortem study, the submucosal vascular pl exus derived from heal, but not jejunal short vessels, comprised end a rteries with little or no communication with the submucosal plexus ari sing from long vessels. Prior ligation of ileal, but not jejunal, shor t vessels resulted in a filling defect of the submucosal plexus along the mesenteric margin in three of the four specimens. Ligation of heal and jejunal long vessels did not affect carbon ink perfusion of the b owel wall. Conclusions - In the human terminal ileum, the short vessel s supplying the mesenteric margin are end arteries, and their patholog ical occlusion might cause ischaemia of this region. These findings su pport a vascular hypothesis for Crohn's disease and may explain, in pa rt, both the ileal and mesenteric distribution of Crohn's disease ulce rs.