How to use it
Score the first ileocolonoscopy after an ileocolonic resection, ideally 6–12 months after surgery. Then answer three context questions so the plan fits the patient: risk factors at surgery, current postoperative therapy, and whether an anti-TNF failed before surgery.
The score
| Grade | Endoscopic findings |
|---|---|
| i0 | No lesions in the neoterminal ileum |
| i1 | 5 or fewer aphthous lesions |
| i2 | More than 5 aphthous lesions with normal mucosa between, skip areas of larger lesions, or lesions confined to the ileocolonic anastomosis |
| i2a (modified) | Lesions confined to the anastomosis, with or without 5 or fewer aphthous lesions in the ileum |
| i2b (modified) | More than 5 aphthous ulcers or larger lesions with normal mucosa between, in the neoterminal ileum, with or without anastomotic lesions |
| i3 | Diffuse aphthous ileitis with diffusely inflamed mucosa |
| i4 | Diffuse inflammation with large ulcers, nodules or narrowing |
Endoscopic recurrence is i2 or worse. That threshold drove step-up in POCER and is the end point in PREVENT and in the AGA guideline. In the original cohort, 73% of patients had lesions within a year of surgery, but only 20% had symptoms (Rutgeerts 1990).
i2a or i2b: does it matter?
The modified score splits i2 because anastomotic ulcers may be ischaemic rather than Crohn’s disease (Rivière 2019). The evidence is mixed:
- Same risk: an individual patient data meta-analysis of 400 patients found no difference in clinical or surgical recurrence between i2a and i2b (Rivière 2023), and suggested treating all i2 alike.
- Lower risk for i2a: in cohorts, i2a did not progress more than i0–i1, while i2b did (Ollech 2019; Bachour 2022). In 652 patients, surgery followed in 12.9% with i2a vs 19.1% with i2b (Bak 2024).
The tool therefore counts i2a as recurrence but offers two options: escalate as for i2b, or monitor closely and escalate if ileal lesions appear. Anastomotic lesions are also the least reliably scored part (kappa 0.46; Bak 2024).
Management pathway
- At surgery, stratify risk. ECCO 2024 suggests prophylaxis after ileocolic resection for high-risk patients: smoking, penetrating disease, or an intra-abdominal septic complication or fistula. Other reported risk factors include a previous resection, perianal disease, age 30 or younger and 50 cm or more of small-bowel disease (Hanzel 2022). AGA 2017 suggests early drug prophylaxis over waiting for endoscopic recurrence, but lower-risk patients may reasonably choose endoscopy-guided care.
- Prophylaxis: anti-TNF and/or a thiopurine (AGA 2017). Infliximab halved endoscopic recurrence (PREVENT); vedolizumab reduced it too (REPREVIO). AGA suggests against 5-ASA, budesonide and probiotics.
- Ileocolonoscopy at 6–12 months for everyone, on prophylaxis or not (AGA 2017; ECCO 2024 statement 4.22; ECCO-ESGAR-ESP-IBUS 2025).
- Step up for i2 or worse. AGA suggests initiating or optimising anti-TNF and/or thiopurine. POCER stepped up from a thiopurine to adalimumab with a thiopurine, then to weekly adalimumab, and cut recurrence at 18 months from 67% to 49%.
- Keep monitoring. In POCER, 41% of patients in remission at 6 months had recurred 12 months later.
If an anti-TNF failed before surgery, the tool suggests another class. Vedolizumab has randomised data for prevention (REPREVIO); ustekinumab has observational data (ECCO 2024). Evidence for treating established recurrence with these drugs is limited.
Monitoring between colonoscopies
| Test | Performance for endoscopic recurrence | Source |
|---|---|---|
| Calprotectin 50 µg/g | Sensitivity 76%, specificity 66% | Samnani 2025 |
| Calprotectin 150 µg/g | Sensitivity 70%, specificity 69% (best overall) | Tham 2018 |
| CRP 5 mg/L | Sensitivity 45% (too insensitive) | Samnani 2025 |
| Intestinal ultrasound | Sensitivity 92%, specificity 76% (85% with optimised criteria) | Samnani 2025 |
| BWT ≥5.5 mm on ultrasound | Severe recurrence (≥i3), specificity 98% | Rispo 2018 |
ECCO-ESGAR-ESP-IBUS 2025 says intestinal ultrasound or MR enterography with calprotectin 3–6 months after surgery could detect early recurrence, but still recommends endoscopy at 6–12 months. For ultrasound, wait at least 4 weeks after surgery, do the first scan 3–12 months after it, and focus on the neoterminal ileum and its inlet (Ma 2026). Use IBUS-SAS to record the segment.
Pitfalls
- Score only the neoterminal ileum and anastomosis. The Rutgeerts score does not capture colonic recurrence (ECCO-ESGAR-ESP-IBUS 2025); use SES-CD for the colon.
- Anastomosis type. The modified score was developed for end-to-end anastomoses (ECCO-ESGAR-ESP-IBUS 2025). Side-to-side anastomoses add an ileal inlet and blind loops, which newer scores assess separately (Bak 2024).
- Reliability is moderate, especially around the i1/i2 line that drives treatment (ECCO-ESGAR-ESP-IBUS 2025). Photograph the anastomosis and the ileum.
- Before a new biologic or thiopurine, complete pre-treatment screening. On an anti-TNF, check drug levels before calling it a failure.
The plan follows AGA 2017 and ECCO 2024, with monitoring from the 2025 ECCO-ESGAR-ESP-IBUS guideline.