The rates of post-operative recurrence (endoscopic) in population based-studies arevariable and occur in around 50-60% of patients (1). Therefore, while common, post-operative recurrence does not occur universally, and not all patients have the same risk of POR.Identifying patients at higher risk for POR is important because those patients may benefitof therapeutic prophylaxis immediately after surgery. Some of the most consistent risk factors that increased the risk of POR are smoking, prior history of surgery, and male gender. Penetrating disease, identified in older studies, had not been identified as risk factors inmost modern cohorts2. Starting prophylaxis with Anti-TNF after surgery has been identified consistently to be a protective risk factor for POR

Following surgery some patients may experience worsening diarrhea for different reasons. Conditions such as bile acid malabsorption, small intestinal bacterial overgrowth (SIBO), or infections can all cause diarrhea that may mimic Crohn’s disease recurrence. Failing to consider these alternative causes may result in over- or inappropriate treatment. Relying solely on symptoms to establish recurrence in Crohn’s disease is problematic due to the poor correlation between clinical symptoms and actual endoscopic recurrence. Endoscopic recurrence can occur in the absence of clinical symptoms, and therefore, to accurately assess recurrence endoscopic evaluation should be performed.

Ileocolonoscopy should be conducted 6-12 months post-surgery, even in asymptomatic patients. The POCER trial demonstrated that treatment adjustments based on endoscopic findings led to better outcomes, highlighting the importance of objective measures in managing postoperative Crohn’s disease.3 An adequate monitoring plan should be put in place after surgery, with regular assessement of clinical symptons and biomarkers (CRP and fecal calprotecin). Ileocolonoscopy should be planed and assessment of post-operative recurrence by assessing the lesions at the anastomosis should be performed. There is no validate scoring system, but the most widely used is the Rutgeerts score. It is important to highlight that the Rutgeerts score was developed to assess end-to-end anastomosis, no longer performed in the moderns days of surgery, where side-to-side anastomosis is the norm. Therefore, besides applying a score, it is also important to be descriptive in terms of describing the location of the different lesions.

Smoking has been shown to significantly increase the risk of both clinical and surgical recurrence in CD patients after surgery. Patients who smoke have a 2.5-fold increased risk of surgical recurrence and a twofold risk of clinical recurrence compared to non-smokers.4 The odds ratio for clinical recurrence for current smokers is between 2 and 3. Importantly, smoking is the only modifiable risk factor identified, and smoking cessation appears to decrease the risk of recurrence to that of a non-smoker .Given the strong evidence linking smoking to post-operative recurrence, failure to address smoking cessation represents a missed opportunity for improving patient outcomes.

Patients with ileal resection are at significantly increased risk for vitamin B12 deficiency due to the role the terminal ileum plays in vitamin B12 absorption. The terminal ileum is the primary site where vitamin B12, bound to intrinsic factor produced in the stomach, is absorbed into the bloodstream, and therefore ileal resection may impact the body’s ability to absorb vitamin B12. The extent of malabsorption is directly related to the length of ileum resected. The impact of ileal resection on vitamin B12 absorption may not always be immediately apparent, which can lead to delayed diagnosis if not properly monitored. Following surgery, serum vitamin B12 levels may remain within the normal range due to hepatic storage. Factors such as bacterial overgrowth, which can occur after ileal resection, may further interfere with vitamin B12 absorption. Given these mechanisms, regular monitoring (at least yearly) and potential supplementation of vitamin B12 are essential for patients who have undergone ileal resection.