Intestinal Stomas and Enterocutaneous Fistulas: Types, Management, and Complications

PART 1: INTESTINAL STOMAS

Definition and Purpose

Classification of Stomas

• Ileostomy - from small bowel (ileum); produces liquid to semi-liquid effluent; requires spouted/everted construction (Brooke ileostomy) to prevent skin damage from digestive enzymes
• Colostomy - from large bowel; effluent becomes progressively more formed depending on the site:
  • Ascending colostomy: liquid effluent
  • Transverse colostomy: semi-formed
  • Descending/sigmoid colostomy: formed stool; preferred for permanent diversion

• End stoma - bowel is divided; the proximal end is brought to the skin. The distal end is either brought out as a mucus fistula or closed and left in the abdomen (Hartmann's pouch).
• Loop stoma - a loop of bowel is brought through the wall; a rod or bridge keeps it above the skin level. Provides diversion but is temporary; loop ileostomy is preferred over loop transverse colostomy because transverse loop colostomies are large, prone to prolapse, and difficult to pouch.
• Double-barrel stoma - both proximal and distal limbs are brought to the skin surface as two separate openings; used in emergency cases, significant inflammation, or when a standard loop cannot be safely created.
• End-loop (end-loop ileostomy) - hybrid configuration.

• Temporary stoma - used to protect a distal anastomosis, manage sepsis, or allow healing of distal pathology. Anticipated to be closed later.
  • Ghost ileostomy: a loop of ileum is prepared and marked but sutured beneath the skin without being made functional; converted to a functional ileostomy quickly if an anastomotic leak occurs post-operatively.
• Permanent stoma - required when bowel continuity cannot be restored (e.g., abdominoperineal resection for rectal cancer, end-stage IBD, permanent incontinence, or bedridden patients).

• Enteric stomas (stool)
• Urinary conduits (urostomies): e.g., ileal conduit

• Incontinent stoma - standard; stool drains freely into an appliance
• Continent stoma - e.g., Koch pouch (continent ileostomy) - an internal reservoir with a nipple valve; the patient catheterizes the pouch to empty it

Stoma Siting

Stoma Construction Technique

• A disk of skin 1.5-2 cm in diameter is excised
• The rectus muscle is split (muscle-splitting approach); the rectus sheath is sharply divided
• The aperture should admit two fingers (typical diameter)
• Blood supply is tested before and after passing bowel through the wall
• Ileostomies are matured with eversion (Brooke technique): 2-3 cm of bowel is everted to form a spout, directing the corrosive effluent away from the skin
• Colostomies need protrude only 0.5-1 cm above the skin level

Stoma Complications

Early Complications

Late Complications

• Can occur at skin or fascial level, or both
• Early causes: inadequate skin opening, ischemia, mucocutaneous separation, abscess
• Late causes: Crohn's disease, malignancy, scarring
• Symptoms: obstructive symptoms, squirting of stool under pressure
• Management: gentle digital dilation, low-residue diet; severe cases require surgical revision

• More common with loop colostomies; almost always the efferent limb prolapses
• Associated with parastomal hernia
• Rare after ileostomy

• The most common late complication of colostomy
• Bowel/omentum protrudes through the abdominal wall fascial defect adjacent to the stoma
• Symptoms: poor appliance fitting, pain, obstruction, strangulation
• Management: symptomatic hernias require repair
  • Simple suture repair: nearly 100% recurrence rate
  • Mesh repair (open or laparoscopic): preferred
  • Stoma relocation to opposite side
  • Prophylactic mesh at time of stoma creation: decreases parastomal hernia risk by ~40% per a meta-analysis of 12 RCTs, though recent RCTs show less benefit

• Irritant/contact dermatitis: confluent erythema from effluent leakage; treated by proper appliance fitting and barrier products
• Allergic dermatitis: patch testing to identify allergen
• Pseudoverrucous lesions: warty hyperkeratotic overgrowth from chronic irritation; treated with silver nitrate
• Candidiasis: bright red pustular rash in moist area; topical antifungal powder
• Cellulitis: oral/topical antibiotics
• Folliculitis: from traumatic hair removal; proper clipping technique
• Pyoderma gangrenosum: rare; may be associated with IBD

• Dehydration and electrolyte abnormalities (bypasses colon's water-absorbing capacity)
• Target output <1500 mL/day; managed with bulk agents, loperamide, codeine, tincture of opium, or octreotide
• Calcium oxalate urinary stones
• Gallstones (altered bile salt metabolism)

PART 2: ENTEROCUTANEOUS FISTULA (ECF)

Definition

Classification of Intestinal Fistulas

• Iatrogenic (>80%): anastomotic leak, inadvertent enterotomy during adhesiolysis (frequency increases with each laparotomy), or hernia repair mesh erosion
• Spontaneous: Crohn's disease, diverticulitis, malignancy, radiation enteritis, appendicitis, pancreatitis, peptic ulcer disease

• Simple - single tract, no abscess, no associated distal obstruction
• Complex - multiple openings, enteroatmospheric, associated with abscesses, radiation damage, or open abdomen

Etiology in Detail

Factors Preventing Spontaneous Fistula Closure

Clinical Presentation

• Acute phase (postoperative): Fever, leukocytosis, wound erythema/discharge. The first sign is often a serosanguinous then enteric fluid from the wound between days 5-10.
• Chronic/spontaneous ECF: Presents with drain/wound discharge recognizable as enteric content; may have weight loss, malnutrition, and signs of sepsis.
• Peristomal/pericutaneous skin excoriation - especially with proximal small bowel content (high enzyme content).
• High-output fistulas cause rapid fluid/electrolyte losses: hyponatraemia, hypokalaemia, hypomagnesaemia, metabolic acidosis.

Diagnosis

1. CT abdomen with oral/IV contrast - First-line investigation; identifies the fistula tract, any intra-abdominal abscesses, and associated pathology.
2. Small bowel series or enteroclysis - Demonstrates the bowel segment of origin; rules out distal obstruction.
3. Fistulogram - Contrast injected through a catheter into the fistula tract under pressure; most sensitive for tract anatomy when CT is non-diagnostic. Essential for surgical planning.
4. Endoscopy - To evaluate for IBD, malignancy, or distal obstruction.

Management

Framework 1: SNAP (Bailey and Love)

• S - Elimination of Sepsis and Skin protection
• N - Nutrition (parenteral or enteral depending on fistula level and output)
• A - Anatomical assessment (imaging, fistulography)
• P - Definitive Planned surgery

Framework 2: The Five Phases (Maingot's Abdominal Operations / Evenson & Fischer)

• IV fluid resuscitation; correct electrolyte abnormalities
• Drain abscesses percutaneously (CT-guided)
• Antibiotics for sepsis
• Skin protection: hydrocolloid barriers, ostomy appliances, or wound ostomy continence (WOCN) nurse involvement
• Quantify output, establish fistula category

• CT, small bowel series, fistulogram
• Define the bowel segment of origin, length of fistula tract, any distal obstruction, associated abscess
• Critical because distal fibrostenotic disease will prevent spontaneous closure

• Establish timeline for conservative management (typically 4-6 weeks of optimized nutrition)
• Decide on route of nutrition
• Optimize medications (especially in IBD - biologics consideration)
• Identify non-modifiable factors (radiation, malignancy, mesh) that make spontaneous closure unlikely

• Time: surgery should NOT be performed early in a septic, malnourished patient - "an early return to theatre in a septic, malnourished patient is doomed to failure" - Bailey and Love
• Anastomosis should be avoided if:
  • Continuing intra-abdominal sepsis
  • Hypoalbuminaemia (<32 g/dL)
• Operative approach: enter abdomen through previously unoperated area (cephalad or caudad to prior incision); inadvertent enterotomy occurs in ~20% of reoperations
• Resect the fistula-bearing bowel segment and restore continuity; avoid anastomosis in a hostile abdomen

• Long-term nutritional and ostomy/wound support
• Psychological support

Nutritional Management (Key Component)

• High-output or proximal fistula: Total Parenteral Nutrition (TPN) is preferred; reduces fistula output, allows bowel rest, supports spontaneous closure without increasing mortality. Protein target: 1.5-2.0 g/kg/day (higher with greater output).
• Low-output or distal fistula (<200 mL/day or distal bowel): Trial of enteral nutrition (EN) with careful monitoring for increased output.
• Fistuloclysis: Feeding through the fistula itself (re-infusion of enteric contents and tube feeds via the fistula opening, distally). Can replace TPN when spontaneous closure is unlikely and distal bowel is accessible.

• Octreotide (somatostatin analogue): Reduces secretion and fistula output; particularly useful in high-output fistulas. A meta-analysis confirmed reduced hospital stay and time to closure with somatostatin, though ultimate closure rates were not significantly different. - Schwartz's Principles of Surgery
• Antibiotics: Ciprofloxacin + metronidazole (or rifaximin) for aerobic and anaerobic gut flora coverage, especially in home therapy scenarios.
• Biologics (in IBD-related ECF): Anti-TNF agents (infliximab) can induce fistula closure.

Wound Care / Skin Protection

• Simple ECF: managed like a stoma with hydrocolloid barrier and appliance
• Vacuum-assisted closure (VAC/NPWT):
  • Low-output ECF: >85% closure rates with VAC devices
  • High-output ECF: lower success rates; fistulas with visible mucosa are unlikely to close
  • Also used for enteroatmospheric fistulas with modified sump tube systems
• Complex/enteroatmospheric fistulas require involvement of WOCN nurses and complex wound management strategies

Spontaneous Closure Rates

Complications of ECF

Summary Comparison: Stoma vs. ECF

• Bailey and Love's Short Practice of Surgery, 28th ed., Ch. 74
• Schwartz's Principles of Surgery, 11th ed., Ch. 28
• Sabiston Textbook of Surgery, Ch. 95
• Fischer's Mastery of Surgery, 8th ed., Ch. 130, 142, 143
• Maingot's Abdominal Operations, Ch. 10
• Current Surgical Therapy, 14th ed.
• Yamada's Textbook of Gastroenterology, 7th ed.