Special Surgery 20. Surgical Aspects of Crohn Disease

I. Crohn Disease Overview

Definition and Morphology

• Crohn disease: Chronic transmural inflammatory disease of the GI tract
• Location: Any part from mouth to anus
• Most common location: Terminal ileum and right colon
• Pattern: Skip lesions
• Macroscopy:

• Aphthous ulcers
• Cobblestone appearance
• Strictures, fistulas
• Thickened bowel wall

• Microscopy: Transmural inflammation, non-caseating granulomas in about 50%
• Surgery is not curative → Used for complications or failure of medical therapy

Clinical Features

Intestinal Manifestations

• Onset: Often teenage/young adult
• Chronic diarrhea
• Abdominal pain → Usually RLQ
• Weight loss, fever, fatigue
• Malabsorption → Steatorrhea
• Occult bleeding
• Perianal pain/discharge → Fistula or abscess

Extraintestinal Manifestations

• Joints: Arthritis, ankylosing spondylitis
• Skin: Erythema nodosum, pyoderma gangrenosum
• Eyes: Uveitis, episcleritis
• Hepatobiliary: Primary sclerosing cholangitis, less common than in UC

Complications

• Intestinal stricture → Obstruction
• Fistulas:

• Entero-enteric
• Enterocutaneous
• Enterovesical
• Rectovaginal
• Perianal fistula

• Abscess → Perianal or intra-abdominal
• Perforation → Rare, life-threatening
• Hemorrhage → Rare surgical indication
• Vitamin B12 deficiency, iron-deficiency anemia
• Malnutrition, growth retardation in children
• Increased colorectal cancer risk in long-standing colonic Crohn disease
• Short bowel syndrome risk after repeated resections

II. Diagnosis and Classification

Diagnosis

• Lab:

• Inc CRP, ESR, WBC
• Anemia → Vitamin B12 deficiency, Fe deficiency
• Inc fecal calprotectin
• Check nutritional status before surgery: Albumin, weight loss, vitamin deficiencies

• Colonoscopy + ileoscopy:

• Aphthous ulcers
• Cobblestone appearance
• Skip lesions
• Strictures
• Biopsy for histology

• Biopsy: Chronic active inflammation, non-caseating granulomas if present
• Capsule endoscopy: Small bowel Crohn disease

• Avoid if stricture suspected unless obstruction is excluded

• CT/MRI enterography:

• Disease extent
• Fistulas
• Abscesses
• Strictures and prestenotic dilatation

• MRI pelvis: Perianal fistula/abscess mapping

Montreal Classification

Location

• L1: Ileum
• L2: Colon
• L3: Ileum + colon
• L4: Upper GI tract

Behavior

• B1: Inflammatory, non-stricturing, non-penetrating
• B2: Stricturing
• B3: Penetrating
• p: Perianal disease modifier

III. Medical and Surgical Treatment

Medical Therapy

Induction

• Corticosteroids:

• Prednisolone
• Budesonide for mild ileocecal disease

• Immunomodulator: Azathioprine
• Biologics:

• Anti-TNF: Infliximab, adalimumab
• Ustekinumab
• Vedolizumab

• Small molecules:

• JAK inhibitor: Upadacitinib
• Tofacitinib: Mainly UC, not standard Crohn therapy

• Antibiotics: Metronidazole/ciprofloxacin for abscess or selected fistulizing/perianal disease

Maintenance

• Immunomodulators: Azathioprine / 6-MP
• Biologics continued according to response and recurrence risk
• Steroids are not maintenance therapy

Surgical Principles

• Surgery is not curative → Recurrence is common
• Goal: Treat complications, preserve bowel length, preserve function
• Minimize bowel resection → Prevent short bowel syndrome
• Prefer elective surgery after optimization when possible
• Laparoscopic approach preferred if feasible
• Multidisciplinary decision: Surgeon + gastroenterologist + radiologist + dietitian + stoma nurse

Indications for Surgery

1. Obstruction from fibrotic stricture
2. Perforation or diffuse peritonitis
3. Abscess not controlled by antibiotics/drainage
4. Symptomatic or persistent fistula
5. Perianal abscess/fistula requiring drainage or seton
6. Hemorrhage, rare
7. Failure of optimized medical therapy
8. Suspicion of malignancy/dysplasia
9. Growth retardation in children, selected cases

IV. Surgical Procedures and Postoperative Care

Limited Bowel Resection

• Ileocecal resection: Most common Crohn operation
• Indications:

• Localized terminal ileal/ileocecal stricture
• Localized fistulizing disease
• Inflammatory mass refractory to medical therapy

• Principle: Resect only the macroscopic diseased segment causing complication
• Do not perform wide margins for microscopic inflammation
• Temporary/diverting stoma if anastomosis is unsafe:

• Sepsis or abscess
• Severe malnutrition
• High-dose steroids
• Poor tissue quality
• Emergency surgery

Stricturoplasty

• Bowel-sparing operation for fibrotic small-bowel strictures
• Indications:

• Multiple strictures
• Previous resections
• Short bowel risk

• Techniques:

• Heineke-Mikulicz: Short stricture
• Finney: Longer stricture

• Avoid if perforation, uncontrolled abscess/sepsis or malignancy suspicion

Abscess and Fistula Surgery

• Abscess:

• Antibiotics
• Percutaneous/CT-guided drainage if feasible
• Elective resection later if persistent diseased segment, stricture or recurrent abscess

• Free perforation or diffuse peritonitis → Emergency surgery
• Fistula surgery depends on type and symptoms:

• Resection of diseased bowel segment
• Closure/repair of fistula tract if needed
• Temporary stoma in complex cases

Perianal Crohn Disease

• Exclude and drain abscess before biologic escalation
• MRI pelvis + examination under anesthesia define fistula anatomy
• Seton placement:

• Maintains drainage
• Prevents recurrent abscess
• Combined with antibiotics and anti-TNF therapy when appropriate

• Advanced flap repair or diverting stoma in selected severe/refractory cases
• Protect anal sphincter and continence

Postoperative Care and Recurrence

• Recurrence is common, especially near anastomosis/neoterminal ileum
• Risk is reduced by:

• Smoking cessation
• Postoperative medical prophylaxis in high-risk patients
• Azathioprine or anti-TNF therapy according to risk and previous treatment

• Endoscopic surveillance detects early recurrence
• Monitor symptoms, CRP, fecal calprotectin and nutritional status
• Optimize nutrition before and after surgery

Exam Summary

• Crohn disease: Transmural, skip lesions, terminal ileum/right colon common
• Main surgical problems: Stricture, obstruction, fistula, abscess, perforation
• Surgery is not curative → Bowel-sparing principle
• Ileocecal resection is the most common operation
• Stricturoplasty preserves bowel in fibrotic strictures
• Abscess: Drain first if possible, then elective resection if needed
• Perianal disease: Drain abscess, seton for fistula, coordinate with biologics