Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) currently affecting one person in a thousand in France. It can lead to numerous digestive complications such as fistulas, abscesses or stenosis. Despite numerous therapeutic advances, the rate of patients requiring surgery remains very high, with approximately 50% requiring at least one surgical intervention at 10 years after disease diagnosis. However, surgical treatment is not curative, the postoperative recurrence rate being very high, from 65 to-90% endoscopic recurrence at 1 year. The ileocolonic anastomosis is the main site of postoperative recurrence currently defined by a Rutgeerts score (≥i2) 6 months after surgery. In 2003, Kono et al. described a new operative technique that could reduce the rate of post-operative recurrence: a termino-terminal ileocolonic anastomosis, anti-mesenteric, with a supporting column to prevent distortion and anastomotic stenosis (Kono-S anastomosis). The study showed no decrease in endoscopic recurrence rate at 1 year (83% vs 79%), but a significant decrease in surgical recurrence rate at 5 years (15% vs 0%). Recently, a randomized Italian monocenter study showed a significant decrease in endoscopic recurrence rate at 6 and 18 months (22.2% versus 62.8% and 25% versus 67.4%), as well as a decrease in clinical recurrence. The limitations of this study are its monocentric nature and the lack of centralization of the endoscopic analysis to assess the primary endpoint. This surgical technique has been performed in some centers for ileocolonic Crohn's surgery since 2020. Nevertheless, the level of evidence remains too low to establish practice recommendations. The KOALA study will be the first prospective, multicenter, randomized study comparing KONO-S anastomosis and conventional anastomosis for ileocolonicresection of Crohn's disease, with blinded and centralized evaluation of recurrence.

Inclusion Criteria:

• Adult patient ≥ 18 years and ≤75 years
• With Crohn's disease.
• Requiring a first ileocolonic resection: fistulizing, abscessed, or stenosing disease or disease refractory to medical treatment.
• Affiliated to the French social security system.

Exclusion Criteria:

• Previous ileocolonic resection
• Contraindication to postoperative endoscopy.
• Anastomosis with a planned defunctioning protective stoma.
• Emergency surgery (peritonitis).
• Lack of consent to the study.
• Pregnant patients.
• Refusal to participate or inability to provide informed consent.
• Patient under legal protection (individuals under guardianship by court order)