Clinical decision support

Practice guidelines and risk calculators

Third-party guidelines and prediction tools relevant to IBD surgery, each independently verified against PubMed. These are external documents and tools, linked, not reproduced, and not evidence-gated by this site.

Practice guidelines

• Clinical Practice Guideline for the Surgical Management of Ulcerative Colitis ASCRS · 2026 · PMID 42165399 · Dis Colon Rectum
  When and how to operate in UC, indications in medically refractory and acute severe disease, operative choice for dysplasia/cancer, IPAA staging and reconstruction technique.
• ECCO Guidelines on Therapeutics in Ulcerative Colitis: Surgical Treatment ECCO · 2026 · PMID 42381162 · J Crohns Colitis
  European counterpart on surgery for medically refractory UC, perioperative optimisation, surgical strategy and technique, and centre-expertise requirements.
• The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Surgical Management of Crohn's Disease ASCRS · 2020 · PMID 32692069 · Dis Colon Rectum
  Operative indications and technique across ileocolic, small-bowel, colonic and perianal Crohn's, including anastomotic configuration and strictureplasty.
• ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment ECCO · 2024 · PMID 38878002 · J Crohns Colitis
  Preoperative optimisation, management of immunosuppression before surgery, and technical guidance for common Crohn's operative scenarios.
• ACG Clinical Guideline Update: Ulcerative Colitis in Adults ACG · 2025 · PMID 40701556 · Am J Gastroenterol
  Defines the medical ceiling a surgeon is operating against, treatment targets, advanced-therapy positioning, and the medical management of acute severe UC before colectomy.
• ACG Clinical Guideline: Management of Crohn's Disease in Adults ACG · 2025 · PMID 40701562 · Am J Gastroenterol
  Medical management of luminal, stricturing and fistulising Crohn's, plus CRC surveillance in Crohn's colitis, the context for operative timing.
• AGA Clinical Practice Guideline on the Management of Pouchitis and Inflammatory Pouch Disorders AGA · 2024 · PMID 38128971 · Gastroenterology
  GRADE-based medical management of pouchitis, Crohn's-like disease of the pouch and cuffitis, what to exhaust before considering pouch revision or excision.
• ECCO Topical Review on Pouch Disorders ECCO · 2025 · PMID 40574702 · J Crohns Colitis
  Diagnosis and management of inflammatory, functional, structural and neoplastic pouch disorders, the structural/surgical complement to the AGA pouchitis guideline.
• British Society of Gastroenterology guidelines on colorectal surveillance in inflammatory bowel disease BSG · 2025 · PMID 40306978 · Gut
  Risk-stratified surveillance intervals and the endoscopic-versus-surgical management of dysplasia, including the MDT decision to proceed to colectomy.
• British Society of Gastroenterology guidelines on inflammatory bowel disease in adults: 2025 BSG · 2025 · PMID 40550582 · Gut
  Comprehensive UK reference for IBD in adults, updating the 2019 consensus; includes surgical sections and service-organisation standards.
• The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula ASCRS · 2022 · PMID 35732009 · Dis Colon Rectum
  Explicitly covers anorectal fistula and rectovaginal fistula in the setting of Crohn's disease, drainage, seton, flap, LIFT and diversion decisions.
• The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Reduction of Venous Thromboembolic Disease in Colorectal Surgery ASCRS · 2023 · PMID 37318130 · Dis Colon Rectum
  VTE risk stratification and inpatient/extended prophylaxis for colorectal surgery, the highest-yield perioperative guideline for an IBD-surgical population.
• ESPEN guideline on Clinical Nutrition in inflammatory bowel disease ESPEN · 2023 · PMID 36739756 · Clin Nutr
  Malnutrition screening, preoperative nutritional optimisation and prehabilitation in IBD, 71 recommendations, developed with surgeons on the panel.

Risk calculators and prediction tools

• ACS NSQIP Surgical Risk Calculator (v4.0.4) live calculatorexternally validated30-day risk of death and ~15 postoperative complications for a specified CPT procedure · PMID 24055383 Note: It has been formally externally validated in IBD surgery and it FAILED. Lin et al. (J Crohns Colitis 2023;17(1):73-82; PMID 35973971) found c-statistics of 0.605 any complication, 0.623 serious complication, 0.590 reoperation, 0.621 readmission, 0.574 anastomotic leak, with systematic UNDERESTIMATION of risk. Discrimination is barely above chance in IBD. Do not quote its absolute percentages to an IBD patient; the authors call for recalibration or added variables. This is the only free web tool covering IBD operations, which is exactly why the failure needs to be stated on the page.
• Travis (Oxford) criteria, day 3 of acute severe ulcerative colitis live calculatorexternally validatedPredicts failure of intravenous corticosteroids at day 3 of an ASUC admission, triggering rescue therapy or colectomy discussion Note: Derived 1996 from 48 patients. Its original 85% same-admission colectomy PPV is OBSOLETE. In the biologic era, observed in-hospital colectomy among Oxford-positive patients is roughly 20–36%. It remains a valid discriminator of steroid non-response (independent predictor, and meta-analytic OR ~4.4 for colectomy), so use it to trigger a rescue-therapy decision, never to quote a colectomy probability to a patient. Derivation PMID left blank. The original 1996 Gut record was not independently verified and was not guessed.
• ASUC 1-year colectomy score (Le Baut / Saint-Antoine IBD Network) formula only, no calculatorexternally validatedRisk of colectomy within 1 year of admission for acute severe ulcerative colitis, from four variables available at admission · PMID 31927106 Note: Genuinely validated in a separate 185-patient cohort at two other French centres, but there is NO web implementation, it must be scored by hand. Both cohorts are retrospective, French, and from 2002–2017, i.e. before JAK inhibitors and S1P modulators changed rescue therapy. The extreme strata rest on very small numbers (score 4 = 100% colectomy), so the upper end is imprecise; its real strength is as a negative predictor (NPV 87–92% for score 0).
• Postdischarge VTE risk calculator for IBD surgery (Schlick et al.) formula only, no calculatorderivation cohort only30-day post-discharge venous thromboembolism risk after surgery for IBD · PMID 33077197 Note: DERIVATION ONLY, no external validation and no published web implementation. Built on ACS NSQIP colectomy/proctectomy targeted modules 2012–2018 (n=18,990) with a very rare outcome: 199 events (1.1%), so estimates are unstable in the tails. Do not use it as the sole justification for or against extended prophylaxis; pair it with the ASCRS 2023 VTE guideline, which is the graded recommendation.
• Postoperative Crohn's disease recurrence nomogram (biologic era) formula only, no calculatorexternally validated1-year endoscopic recurrence (modified Rutgeerts score ≥i2b) after ileocolonic resection for Crohn's disease Note: Externally validated in two independent international cohorts, but AUC is only 0.72, adequate for group-level stratification, weak for individual prediction. No web implementation; nomogram lives in the paper. PMID was not retrievable at time of search (published online ~March 2026), cite by DOI and re-check before publishing. Note the paper's own headline result is that biologic prophylaxis reduced recurrence (OR 0.31) irrespective of risk factors, which argues against using the score to withhold prophylaxis from low-risk patients.

Also on MDCalc

These are established instruments already hosted as free, working calculators by MDCalc. We link them rather than rebuild them. Our own decision-support tools above cover what MDCalc does not, and every link below was verified against MDCalc directly.

• Montreal Classification for IBD live calculatorclassificationAssigns Montreal extent (E1-E3) and severity (S0-S3) for UC, and age / location / behaviour (A, L, B) for Crohn's. Note: A PHENOTYPE classification, not a prediction model. Extent should be recorded as the maximum ever documented, not the most recent endoscopic appearance, which underestimates true extent in quiescent disease.
• Truelove and Witts Severity Index for Ulcerative Colitis live calculatorclassificationClassifies a UC flare as mild / moderate / severe. The 'severe' band is the operational definition of acute severe UC (ASUC). Note: A 1955 classification, not a prediction model, never validated to predict steroid failure or colectomy. Deliberately sensitive rather than specific: only ONE systemic criterion beyond the stool count is needed.
• Mayo Score / Disease Activity Index (DAI) for Ulcerative Colitis live calculatoractivity indexThe standard UC trial activity index: stool frequency, rectal bleeding, endoscopy subscore and physician global assessment. Note: An ACTIVITY index, not a risk model. The endoscopic subscore requires a scope, so the 'partial Mayo' seen in clinic is a different instrument with different thresholds, say which one you mean.
• Ulcerative Colitis Endoscopic Index of Severity (UCEIS) live calculatorendoscopicScores endoscopic severity from vascular pattern, bleeding and erosions/ulcers. Note: NOTE the published scoring was CORRECTED: BSG 2019's table 3 printed the original scale where normal = 1 (range 3-11); the corrected scale is normal = 0 (range 0-8). Confirm which scale a given source is using before comparing scores.
• Ho Index for Ulcerative Colitis live calculatorpredictionPredicts failure of intravenous corticosteroids in acute severe UC, from day-3 stool frequency, colonic dilatation and albumin. Note: A rescue-therapy timing aid, not an admission trigger. Derived in a single centre; use alongside, not instead of, the Travis criteria and daily surgical review.
• Pediatric Ulcerative Colitis Activity Index (PUCAI) live calculatorpaediatricNon-invasive paediatric UC activity score; PUCAI >=65 is the paediatric equivalent trigger for admission in acute severe colitis. Note: PAEDIATRIC ONLY. Do not apply adult Truelove-Witts thresholds to children, or PUCAI to adults.
• Crohn's Disease Activity Index (CDAI) live calculatoractivity indexThe historical primary endpoint in Crohn's trials; requires a 7-day patient diary plus labs. Note: Correlates POORLY with endoscopic inflammation. A normal CDAI does not exclude active disease. Explicitly invalid in stricturing/fistulising disease, after extensive resection, and in patients with a stoma. Pair with CRP/faecal calprotectin and imaging.
• Harvey-Bradshaw Index (HBI) for Crohn's Disease live calculatoractivity indexThe single-day simplified CDAI used in clinic; remission conventionally <5. Note: Symptom-driven, so it shares CDAI's blindness to endoscopic activity. The severity bands are from the literature, not from MDCalc's page.
• Simplified Endoscopic Activity Score for Crohn's Disease (SES-CD) live calculatorendoscopicEndoscopic activity in Crohn's: ulcer size, ulcerated and affected surface, and stenosis across five segments. Note: Requires full ileocolonoscopy with all five segments assessed; a partial exam is not scoreable. Objective counterpart to the symptom-based CDAI/HBI.
• Pediatric Crohn's Disease Activity Index (PCDAI) live calculatorpaediatricPaediatric Crohn's activity, adding growth and pubertal parameters absent from the adult indices. Note: PAEDIATRIC ONLY. The growth items are the reason it exists. Do not substitute an adult index in children.
• Wexner Continence Grading Scale (Cleveland Clinic Incontinence Score) live calculatorfunctional outcomeGrades faecal incontinence 0-20 across solid, liquid and gas leakage, pad use and lifestyle alteration. Note: The single most-used continence instrument after ileal pouch surgery and the one reported in most IPAA functional-outcome series. Note MDCalc's URL slug says 'obstructed defecation syndrome' but the tool served is the Wexner continence scale.
• Surgical Apgar Score (SAS) live calculatorperioperativePost-hoc intraoperative risk score from estimated blood loss, lowest mean arterial pressure and lowest heart rate. Note: Calculated AFTER the operation, so it informs postoperative disposition, never the decision to operate. Not validated specifically in IBD surgery.

Guideline summaries hosted by MDCalc:

• ACG Clinical Guideline: Ulcerative Colitis in Adults (via MDCalc) guidelineMDCalc's structured rendering of the ACG UC guideline. Note: The underlying ACG 2019 full text stores its comparison operators corrupted in our corpus (the published PDF encodes '>' as '.' and '<' as ','), so quote thresholds from MDCalc's rendering or the journal, never from our stored text.
• ACG Clinical Guideline: Management of Crohn's Disease in Adults (via MDCalc) guidelineMDCalc's structured rendering of the ACG Crohn's guideline. Note: Check the publication date against the current ACG listing before presenting it as current.
• ACG: Preventive Care in Inflammatory Bowel Disease (via MDCalc) guidelineVaccination, bone health, skin-cancer and cervical-screening recommendations for immunosuppressed IBD patients. Note: Directly relevant before starting biologics or immunomodulators, and a frequent gap in surgical clinics.
• AGA: Pharmacological Management of Ulcerative Colitis (via MDCalc) guidelineAGA medical-therapy recommendations for UC. Note: Medical therapy only. It does not address surgical indications or timing.