Intriguing Role of the Mesentery in Ileocolic Crohn's Disease

Abstract

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease with unknown etiology. Up to 80% of patients will eventually require surgery throughout their lifetime, and often repeated resections are required for disease recurrence. Observations of "creeping fat" surrounding the diseased intestine renewed interest in the mesentery, recently defined as an organ with endocrine and immune functions. According to the inside-out model, the mesentery may be primarily affected in CD and subsequent cause alterations in the mucosa. Recently, lower surgical recurrence rates have been reported with en-bloc excision of the mesentery adjoining the diseased intestine. Results of ongoing randomized controlled trials may clarify the role of the mesentery in CD and possibly lead to its adoption as standard during surgery for Crohn's disease.

Keywords: Crohn's disease; inflammatory bowel disease; mesentery; surgery.

Fig. 1

According to the classical model of CD (the outside-in model, on the right), mucosal damage is a primary pathogenic event, which provokes submucosal and mesenteric inflammation. In the alternative model (inside-out model, on the left) the inflammatory process arises in the mesentery and in mesenteric nodes. In this model mucosal ulceration is a terminal event. (Reprinted with permission from Berh, Inflamm Bowel Dis, Volume 16, Issue 5, 1 May 2010, Pages 896–902, https://doi.org/10.1002/ibd.21171 by permission of Oxford University Press).

Fig. 2

Photograph of a surgical specimen following an ileocolic resection for CD. On the left, the ascending colon and terminal ileum have been excised together with adjoining mesentery. The image on the right demonstrates a conventional ileocolic resection for CD which involved a division of the mesentery flush with the intestine.

Fig. 3

Visual depiction of the Kono-S anastomosis technique. The supporting column is placed immediately behind the posterior wall of the anastomosis. It provides mechanical support preventing deformation and it may function as an isolating structure between the mesentery and the mucosa of the gastrointestinal tract. (Reproduced with permission from Horisberger, et al. Langenbecks Arch Surg (2020). https://doi.org/10.1007/s00423-020-01998-6 ).