Mesenteric Surgical Margin for Crohn's Disease Endoscopic Recurrence

Inclusion criteria: 1. Patients with a clear diagnosis of CD who meet the surgical indications and will undergo one-stage ileocecal resection, 2. Ileocecal CD with localized lesions involving the terminal ileum and cecum, with a total lesion length of \<80 cm, 3. No residual lesions within 50 cm proximal to the ileocecal anastomosis, 4. Patients or their legal guardians who can understand and are willing to participate in this study, provide written informed consent, and have the ability to comply with the protocol. Exclusion criteria: 1. Patients with a history of ileocecal resection, 2. Patients with primary lesions in other locations (e.g., proximal small bowel) that require surgical resection of inflamed intestinal segments other than the ileocecal region (excluding cases with affected other segments of the bowel), 3. Patients with a risk of short bowel syndrome, 4. Patients who require ileostomy formation, 5. Patients with severe anorectal lession, 6. Patients predicted to be unable to receive postoperative drug therapy, 7. Patients unable to return to the hospital for re-examination in a timely manner 8. Patients who have suffered from serious illnesses within the six months before surgery, such as myocardial infarction, active angina pectoris, congestive heart failure, or other diseases believed by the investigator to pose a risk to the patient's safety, 9. Patients with a history of malignant tumors, including melanoma (excluding localized skin cancer), 10. Patients clinically diagnosed with autoimmune diseases other than CD or with evidence of other autoimmune diseases. 11. Pregnant or lactating patients. 12. Patients who cannot be tracked at various study time points for the primary outcome measure. Withdrawal criteria: 1. Subjects lost to follow-up or voluntarily requesting withdrawal. 2. The occurrence of anastomotic fistula after surgery that affects subsequent endoscopic evaluation. 3. Subjects considered unsuitable for further participation in the study by the investigator.