Intestinal Fistula

Intestinal Fistula

1. Intestinal Fistula Dr Sanish Manandhar Resident (General Surgery)

2. Introduction Fistula - defined as an abnormal communication between two epithelialized surfaces Enterocutaneous fistula is the most common type of intestinal fistula Ilem is the most common site of origin of enterocutaneous fistula

3. Classification Anatomical Internal Enteroenteric Enterovesical Enterovaginal Aortoenteric External Enterocutaneous (ECF) - Over 80% of enterocutaneous fistulas represent iatrogenic complications that occur as the result of intestinal anastomotic dehiscences.

4. Classification Physiological Low output - <200 ml/day Moderate output - 200-500 ml/day High output - >500 ml/day Proximal ECFs (e.g., small bowel) are usually high output, whereas distal ones (e.g., colon) tend to be low output.

5. Etiology Congenital Tracheo-oesophageal fistula Acquired Traumatic (75-85%) Iatrogenic - injury to the intestine during handling, lysis of adhesions, abdominal fascial closure, or percutaneous drainage. Penetrating or blunt abdominal traumas Spontaneous (15-25%) Previous intestinal irradiation Intraabdominal sepsis Inflammatory bowel disease, especially Crohn’s disease Malignancy

6. Pathophysiology The manifestations of fistulas depend on which structures are involved Low-resistance enteroenteric fistulas - malabsorption Enterovesicular fistulas - recurrent urinary tract infections Enterocutaneous fistulas High-output fistulas - dehydration, electrolyte imbalance and malnutrition Skin excoriation

7. Factors affecting healing of external intestinal fistulas

8. Presentation Drainage of enteric material through the abdominal wound or through existing drains Pronlonged ileus Abdominal pain Signs of sepsis - fever, tachycardia, leukocystosis Dehydration, fluid and electrolyte abnormalities and malnutrition Often associated with intra-abdominal abscesses

9. Diagnosis CT scan with oral contrast Leakage of contrast material from the intestinal lumen Demonstrate the fistula’s site of origin in the bowel Rule out the presence of intestinal obstruction distal to the site of origin Intra-abdominal abscess Fistulogram Contrast is injected under pressure through a catheter placed percutaneously into the fistula tract Provide information about the length and origin of the fistula

10. Prevention Use of healthy bowel for anastomosis Preoperative mechanical bowel preparation Preoperative intraluminal or systemic antibiotics Preoperative optimization of the nutritional status Sound anastomotic techniques

11. Management Stabilization Fluid and electrolyte resuscitation Nutritional support Control sepsis with antibiotics and drainage of abscess Skin protection and wound management Pharmacological measures Investigation - anatomy of fistula Decision and timing Definitive Management Rehabilitation

12. Fluid and electrolyte resuscitation Restoration of normovolemia, electrolyte replacement, and correcting acid-base balance - requires accurate measurement of fistula output and composition Crystalloid alone is inadequate Albumin and plasma (platelet rich plasma, fresh frozen plasma) Fresh whole blood Urine output should be restored to greater than 0.5 ml/kg/hr

13. Nutritional support Adequately nourished patient - ECF closes spontaneously Should begin as soon as the patient is stabilized Enteral or parenteral route Low output fistula - Enteral feeding High output fistula - TPN to replace fluid losses Advisable to provide at least a part (25%) of daily nutritional requirement through enteral route Enteral feeding tube may be entered beyound the fistula - Fistuloclysis

14. Daily nutritional requirement Low output Calorie requirement: 30-35 kcal/kg/day Protein requirement: 1-2 gm/kg/day High output Calorie requirement: 45-50 kcal/kg/day Protein requirement: 1.5-2.5 gm/kg/day Vitamins, trace elements, essential fatty acids should be provided

15. Control sepsis and drainage of abscess Recognition of residual or ongoing sepsis - fever, tachycardia, leukocytosis and failure to improve in general condition Appropriate antibiotics should be used Often have accompanying intraabdominal abscess Drainage of obvious abscesses - radiological guided aspiration Purulence is thick and cannot be aspirated - drainage in the operating room

16. Skin care & wound management Prevent skin excoriation - stomahesive paste, aluminium paint Fistula output <50 mL/day can be managed with dressing and skin barrier Fistula output >500 mL/day usually requires a pouch system NG tube placement - decompression NPO TPN Placement of sump drain and vacuum assisted closure (VAC) device - apply negative pressure and help to control the drainage and consequently minimize wound size

17. Pharmacological measures PPI and H 2 blockers - to decrease gastric secretions Somatostatin analogues (octreotide) - decreased fistula output Infliximab (monoclonal antibody to TNF-α) may help with fistula closure in patients with Crohn’s disease

18. Investigations CT scan - oral contrast Fistulogram - anatomy of fistula (length / width) USG - locate intraabdominal abscess; USG guided aspiration

19. Decision and timing Sepsis is controlled, patient’s fluid and nutrition status is improving, and the wound is managed - the probability of spontaneous closure and timing of surgical intervention needs to be considered Most fistulas that closes spontaneously - within first 4 weeks Should be waited atleast 8 weeks for fistula to heal spontaneously before surgery is considered

20. Decision and timing Surgical therapy is inevitable in many cases, especially when unfavorable characteristics are present Surgical intervention for ECFs should be delayed until both the intraabdominal and systemic conditions have been optimized

21. Aids to closure Keep edges protected and clean Sumps with gentle suction Keep stool and pus away from edges

22. Definitive management - Surgery Should only be attempted after an adequate trial of soft sumps, antibiotics, nutrition, and keeping the patient’s abdomen clean If no closure has occurred in 60 days - show no sign of closing The incision should be made in a clean area away from the fistula - k eep skin edges clean Lysis of adhesions - if possible, avoid making enterotomies

23. Surgery Free up the skin around the fistula and mobilize the fistula - u sually not possible without enterotomies Resect shorter lengths of bowel as much as possible Two-layer interrupted anastomosis carried out with non-absorbable suture Presence of extensive infection - divided intestinal segments are exteriorized

24. Post-operative care and rehabilitation Ambulation Wound should be reinforced with bulky dressings Do not be in a rush to feed the patient When feeding, maintain calories and protein until bowel function is normal Make certain caloric and protein intake are adequate before stopping total parenteral nutrition Allow 4 to 6 months of adequate nutritional support and rehabilitation before patients should think about returning to work

25. Management of enterocutaneous fistula

26. References Williams N, O’Connell PR, McCaskie AW. Bailey & Love’s Short Practice of Surgery . 27th edition. Florida (US): CRC Press; 2017. Townsend CM et al. Sabiston: Textbook of Surgery: The Biological Basis of Modern Surgical Practice . 21st edition. Missouri (US): Elsevier; 2022. Brunicardi FC et al. Schwartz’s: Principles of Surgery . 11th edition. McGraw-Hill Education; 2019. Cameron JL, Cameron AM. Current Surgical Therapy . 13th edition. Elsevier; 2020.

27. Thank you