The study is looking at the role of the mesentery in disease recurrence for ileocolic Crohn's disease. It is a prospective study that has been designed to perform extended mesenteric excision on patients undergoing their first ileocolic resection for Crohn's disease. Endoscopic recurrence will be monitored with the hypothesis that patients receiving extended mesenteric ileocolic resection will have reduced endoscopic recurrence at 6 months after resection.

The current standard of care for ileocolic Crohn's disease (CD) is a limited mesenteric resection. There is growing, but still limited, evidence that extended mesenteric excision during ileocolic resection is beneficial in decreasing disease recurrence. We propose a prospective multicenter cohort study to better understand the role of extended mesenteric excision in ileocolic CD and how it affects disease recurrence. The primary outcome of this study will be the rate of endoscopic recurrence at 6 months in patients undergoing first-time resection for ileocolic CD. Secondary outcomes will include endoscopic recurrence at 18 months and rates of recurrence requiring surgery by 2 years. These outcomes will be compared to historical controls (limited mesenteric resection). Our hypothesis is that patients receiving extended mesenteric ileocolic resection will have reduced endoscopic recurrence at 6 months after resection. As seen in previous studies, advanced mesenteric and mucosal disease predicts increased surgical recurrence.

Inclusion Criteria:

• adults >18 years old
• diagnosis of CD limited to the distal ileum/ileocolic region
• no previous ileocolic resection
• all forms of CD presentation will be included - stricturing, fistulizing, perforating etc.

Exclusion Criteria:

• previous ileocolic resection
• other sites of CD
• intraabdominal sepsis