Special Surgery 20. Surgical Aspects of Crohn Disease

I. Crohn Disease Overview Relevant to Surgery

Definition

• Chronic, relapsing inflammatory bowel disease
• Transmural inflammation of GI tract
• Can affect any part from mouth to anus
• Most common location: terminal ileum and right colon
• Surgery treats complications, not the underlying disease
• Recurrence after surgery is common, often at anastomosis/neoterminal ileum

Morphology

• Location: any GI segment
• Pattern: skip lesions
• Macroscopic:

• Aphthous ulcers
• Longitudinal ulcers
• Cobblestone mucosa
• Fat wrapping / creeping fat
• Thickened bowel wall
• Strictures and fistulas

• Microscopic:

• Transmural inflammation
• Fissuring ulcers
• Non-caseating granulomas in a minority; classical but not always present

Clinical Features

Intestinal Manifestations

• Onset often teenage/young adult
• Chronic diarrhea
• Right lower quadrant abdominal pain
• Weight loss, fever, fatigue
• Malabsorption and steatorrhea
• Occult bleeding
• Perianal pain/discharge if fistula/abscess

Extraintestinal Manifestations

• Joints: peripheral arthritis, ankylosing spondylitis, sacroiliitis
• Skin: erythema nodosum, pyoderma gangrenosum
• Eyes: uveitis, episcleritis
• Hepatobiliary: primary sclerosing cholangitis, less common than in ulcerative colitis
• VTE risk increased during active inflammation/hospitalization

Complications Relevant to Surgery

• Fibrotic intestinal strictures → obstruction
• Penetrating disease:

• Entero-enteric fistula
• Enterocutaneous fistula
• Enterovesical fistula
• Rectovaginal fistula
• Intra-abdominal abscess

• Perianal fistula and abscess
• Free perforation, rare but life-threatening
• Bleeding, rare surgical indication
• Vitamin B12 deficiency, iron-deficiency anemia
• Malnutrition and sarcopenia
• Increased colorectal cancer risk in long-standing colonic Crohn disease
• Short bowel syndrome risk after repeated resections

Montreal Classification

Age at Diagnosis

• A1: <17 years
• A2: 17-40 years
• A3: >40 years

Location

• L1: ileum
• L2: colon
• L3: ileocolon
• L4: upper GI involvement; modifier added to L1-L3 if present

Behavior

• B1: inflammatory, non-stricturing, non-penetrating
• B2: stricturing
• B3: penetrating
• p: perianal disease modifier

II. Diagnosis and Preoperative Optimization

Laboratory Tests

• Inflammation:

• CRP, ESR
• WBC/leukocytosis
• Fecal calprotectin increased in intestinal inflammation

• Anemia and nutrition:

• Hb/Hct
• Iron studies
• Vitamin B12, especially terminal ileal disease/resection
• Folate, vitamin D
• Albumin/prealbumin as surgical risk markers

• Before biologics/immunosuppression: infection screening according to protocol, e.g. TB, hepatitis

Endoscopy and Histology

• Ileocolonoscopy with segmental biopsies:

• Aphthous ulcers
• Cobblestone appearance
• Skip inflammation
• Strictures
• Terminal ileum involvement

• Biopsy:

• Chronic active inflammation
• Granuloma can support diagnosis but absence does not exclude Crohn disease
• Biopsy is mucosal/submucosal; it does not reliably show full transmural disease

• Colonoscopy also used for dysplasia/CRC surveillance in colonic Crohn disease

Small Bowel and Cross-Sectional Imaging

• MR enterography or CT enterography:

• Small bowel disease extent
• Inflammatory vs fibrotic stricture features
• Fistulas
• Abscesses
• Prestenotic dilatation

• MRI pelvis:

• Perianal fistula anatomy
• Abscess
• Relation to sphincters

• Capsule endoscopy:

• Small bowel Crohn disease when ileocolonoscopy/imaging inconclusive
• Avoid if suspected stricture unless patency capsule or imaging excludes obstruction

• Intestinal ultrasound can monitor disease in experienced centers

Medical Therapy Overview

Induction

• Corticosteroids:

• Prednisolone/systemic steroids for moderate-severe flare
• Budesonide for mild-moderate ileocecal disease

• Biologics:

• Anti-TNF: infliximab, adalimumab
• Ustekinumab
• Vedolizumab
• Other newer agents depending on local availability/protocol

• Small molecules:

• Upadacitinib is a JAK inhibitor used in Crohn disease in current practice
• Tofacitinib is mainly ulcerative colitis, not standard Crohn disease therapy

• Antibiotics:

• Abscess, perianal sepsis or selected fistulizing disease
• Metronidazole/ciprofloxacin can reduce fistula drainage but are not definitive alone

Maintenance

• Immunomodulators:

• Azathioprine / 6-mercaptopurine
• Methotrexate in selected patients

• Biologics/small molecules continued according to response/risk
• Steroids are not maintenance treatment

Preoperative Optimization

• Prefer elective surgery after optimization rather than emergency surgery when possible
• Control sepsis:

• Antibiotics
• Percutaneous drainage of abscess if feasible

• Correct malnutrition:

• Enteral nutrition preferred if possible
• Parenteral nutrition if severe malnutrition/obstruction/fistula prevents adequate enteral intake

• Correct anemia and vitamin deficiency
• Stop smoking
• Taper steroids if possible; high-dose steroids increase septic/anastomotic risk
• Plan biologic timing individually with gastroenterology; active sepsis is a contraindication
• Mark stoma site preoperatively if stoma possible

III. Surgical Indications and Procedures

General Surgical Principles

• Surgery is not curative
• Operate for complications or refractory disease
• Minimize bowel resection to avoid short bowel syndrome
• Prefer limited resection or stricturoplasty when appropriate
• Laparoscopic approach preferred when feasible
• Multidisciplinary decision: colorectal surgeon, gastroenterologist, radiologist, dietitian, stoma nurse

Indications for Surgery

1. Obstruction from fibrotic stricture
2. Perforation
3. Abscess not controlled by drainage/antibiotics or associated with diseased segment requiring resection
4. Fistulas causing symptoms/complications
5. Perianal abscess/fistula requiring drainage/seton or definitive procedure
6. Massive hemorrhage, rare
7. Refractory disease despite optimized medical therapy
8. Suspicion of malignancy or dysplasia/cancer
9. Growth failure/delayed puberty in pediatric Crohn disease, selected cases

Obstruction / Stricturing Disease

• Differentiate inflammatory stricture from fibrotic stricture:

• Inflammatory component can improve with medical therapy
• Fixed fibrotic stricture usually needs endoscopic or surgical treatment

• Symptoms:

• Crampy abdominal pain
• Vomiting
• Distension
• Weight loss / food avoidance

• Endoscopic balloon dilation:

• Short, accessible, non-angulated stricture
• Commonly anastomotic or short primary stricture
• No abscess/fistula/cancer suspicion

• Surgical options:

• Limited segmental resection
• Stricturoplasty if bowel preservation important

Limited Resection

• Ileocecal resection is the most common Crohn operation
• Indications:

• Localized terminal ileal/ileocecal stricture
• Localized penetrating complication
• Inflammatory mass refractory to medical therapy

• Principles:

• Resect only macroscopic diseased segment causing complication
• Do not chase microscopic inflammation with wide margins
• Side-to-side stapled anastomosis commonly used
• Consider temporary stoma if sepsis, malnutrition, high-dose steroids or poor tissue quality

Stricturoplasty

• Bowel-sparing procedure for fibrotic strictures
• Indications:

• Multiple small bowel strictures
• Previous resections / short bowel risk
• Long segment disease where resection would remove too much bowel
• No active cancer suspicion

• Contraindications/avoid:

• Perforation at stricture
• Uncontrolled abscess/sepsis
• Suspicion of malignancy
• Severe phlegmon or very poor tissue

• Techniques:

• Heineke-Mikulicz: short stricture
• Finney: intermediate/longer stricture
• Michelassi side-to-side isoperistaltic stricturoplasty: long segment, specialist centers

Abscess and Penetrating Disease

• Intra-abdominal abscess:

• Antibiotics
• Image-guided percutaneous drainage if well-defined and accessible
• Optimize nutrition and reduce steroids if possible
• Delayed elective resection if persistent/recurrent abscess, stricture, fistula or refractory diseased segment

• Emergency surgery if:

• Free perforation
• Diffuse peritonitis
• Uncontrolled sepsis
• Drainage impossible and deterioration

Fistula Surgery

• Entero-enteric fistula:

• Observe if asymptomatic and no abscess/obstruction/malabsorption
• Resect diseased segment if symptomatic, associated with abscess/stricture, or causing diarrhea/malnutrition

• Enterovesical fistula:

• Symptoms: pneumaturia, fecaluria, recurrent UTI
• Usually needs resection of diseased bowel and bladder repair/drainage if required

• Enterocutaneous fistula:

• Control sepsis, protect skin, optimize nutrition
• Delay definitive surgery until inflammation controlled and patient optimized when possible

• Rectovaginal fistula:

• Treat active rectal Crohn disease medically first
• Often needs surgical repair; diverting stoma may be required in complex cases

Perianal Crohn Disease

• Always exclude abscess before biologic escalation
• Drain perianal abscess urgently
• MRI pelvis and examination under anesthesia define fistula anatomy
• Seton placement:

• Maintains drainage
• Prevents recurrent abscess
• Often combined with anti-TNF therapy

• Simple low fistula without proctitis:

• Fistulotomy can be considered carefully
• Protect continence

• Complex fistula:

• Long-term loose seton + biologic therapy
• Advancement flap or LIFT in selected controlled disease without active proctitis
• Stem-cell therapy in selected refractory complex perianal Crohn disease where available
• Diverting stoma for severe refractory perianal disease
• Proctectomy is last resort for uncontrolled refractory proctitis/perianal sepsis

IV. Postoperative Management and Recurrence

Postoperative Recurrence

• Surgery is not curative
• Endoscopic recurrence often precedes symptoms
• Typical site: neoterminal ileum/anastomosis after ileocolic resection
• Clinical recurrence risk is high over years; repeated operations increase short bowel risk

Risk Factors for Recurrence

• Smoking
• Penetrating disease
• Perianal disease
• Previous intestinal resection
• Extensive small bowel disease
• Young age at diagnosis
• Positive margins/myenteric plexitis in some pathology risk models

Prevention of Recurrence

• Smoking cessation is essential
• High-risk patients often receive early postoperative prophylaxis:

• Anti-TNF therapy
• Thiopurine such as azathioprine/6-MP
• Other biologics depending on previous exposure and local protocol

• Mesalamine, budesonide and probiotics are not preferred prevention after resection

Postoperative Surveillance

• Ileocolonoscopy 6-12 months after ileocolic resection
• Rutgeerts score assesses endoscopic recurrence in neoterminal ileum/anastomosis
• Escalate/optimize medical therapy if endoscopic recurrence
• Monitor fecal calprotectin, CRP, symptoms and nutrition
• Long-standing colonic Crohn disease needs colorectal cancer surveillance colonoscopy

Stoma and Emergency Surgery Considerations

• Temporary ileostomy can be used when anastomosis is unsafe:

• Sepsis/abscess
• Malnutrition
• High-dose steroids
• Poor tissue quality
• Emergency surgery

• Hartmann procedure is a colorectal emergency operation, not a standard named Crohn ileostomy procedure
• Permanent stoma may be needed for severe refractory perianal disease, proctitis or multiple failed repairs

Exam Pearls

• Crohn surgery = bowel-sparing, complication-driven, not curative
• Ileocecal resection is most common operation
• Stricturoplasty preserves bowel in fibrotic small-bowel strictures
• Drain abscess first when possible, then elective surgery after optimization
• Perianal Crohn: drain abscess, seton for fistula, combine with biologic therapy
• Postoperative ileocolonoscopy at 6-12 months is key because recurrence is often endoscopic first