What are the different types of fistulas and their treatments?

Types of Fistulas and Their Treatments

Fistulas are abnormal communications between two epithelial surfaces and are classified into two major categories: arteriovenous fistulas (for hemodialysis access) and gastrointestinal/genitourinary fistulas (pathologic connections), each requiring distinct management approaches based on anatomical location and complexity. 1, 2

Arteriovenous Fistulas (Hemodialysis Access)

These are surgically created connections between arteries and veins for dialysis access 3:

Types by Location:

• Brescia-Cimino (radiocephalic) fistula: Connects the radial artery to the cephalic vein at the wrist—the most distal and preferred first option 3
• Gracz fistula: Connects the brachial artery to a branch of the medial antecubital vein (perforating vein) below the elbow 3
• Snuff-box fistula: Connects a branch of the radial artery to an adjacent vein in the anatomic snuff box of the hand 3

Treatment Considerations:

• These fistulas require maturation following the "Rule of 6s": minimum 6 mm diameter, less than 6 mm deep, blood flow greater than 600 mL/min, evaluated at 6 weeks post-creation 3

Perianal/Anorectal Fistulas

Anatomical Classification (Parks System):

The Parks classification defines five types based on sphincter relationship 3, 1:

• Superficial fistulas (16% of cases): Involve only distal anal canal without sphincter involvement—lowest complexity 1
• Intersphincteric fistulas (54% of cases): Tract runs between internal and external anal sphincters 1
• Transsphincteric fistulas (21% of cases): Tract crosses through external sphincter into ischioanal fossa 1
• Suprasphincteric fistulas (3% of cases): Tract passes upward above puborectalis muscle, then laterally and downward 1
• Extrasphincteric fistulas (3% of cases): Tract originates outside anal canal, passing from rectum to perineal skin 1

Clinical Classification:

Simple fistulas have: low origin, single external opening, no abscess, no rectovaginal involvement, no stricture 3, 1

Complex fistulas have: high origin, multiple openings, associated abscess, rectovaginal involvement, or active rectal disease 3, 1

Treatment Algorithm:

For simple low fistulas: Perform fistulotomy with healing rates approaching 100%—lay open the primary tract and side tracts 4

For complex fistulas: Place loose, non-cutting seton as primary treatment to establish drainage, with success rates up to 98% when combined with medical therapy 3, 4

Absolute contraindications to fistulotomy: Active proctitis, Crohn's Disease Activity Index >150, perineal Crohn's involvement, or anterior fistulas in females 4

Critical pitfall: Never use cutting setons—they cause incontinence rates up to 57% and keyhole deformity 4

Crohn's Disease-Related Fistulas

Perianal Fistulas in Crohn's:

• Initial management: Control sepsis first with loose seton placement, then initiate medical therapy with antibiotics 4
• Maintenance therapy: Use thiopurines, infliximab, or adalimumab to maintain remission 3, 4
• Seton timing: Keep in place until at least one month after completing anti-TNF induction phase 4

Non-Perianal Crohn's Fistulas:

Enteroenteric fistulas: Often asymptomatic and do not always require surgery unless associated with abscess, stricture, or causing excessive diarrhea/malabsorption 3

Enterovesical fistulas: Medical therapy achieves complete closure in 65.9% of cases—reserve surgery for bowel obstruction, abscess, or medical therapy failure 3

Enterovaginal/rectovaginal fistulas: Medical therapy achieves complete closure in only 38.3% of cases—surgery usually necessary for symptomatic cases, often requiring diverting ostomy 3

Enterocutaneous fistulas: Require period of nutritional optimization, sepsis control, and drainage before definitive surgical management 3

Vesicovaginal Fistulas

Classification:

• High fistulas: Communication between vagina and bladder above sphincter complex 5
• Low fistulas: Communication involving sphincter complex 5
• Simple vs. Complex: Based on size, single vs. multiple tracts, and associated inflammation 5

Etiology-Based Types:

• Iatrogenic (most common in developed countries): Post-hysterectomy, occurring in 1 in 1000 cases 5
• Radiation-induced: Following pelvic radiation therapy—often complex and difficult to repair 5
• Malignancy-associated: Direct tumor invasion requiring complex management 5

Treatment:

• Simple vesicovaginal fistulas: Amenable to endoscopic fulguration 5
• Complex vesicovaginal fistulas: Require surgical repair, with transvaginal approach showing 70% success at first attempt and 92% with two attempts 6
• More than 90% should be repaired vaginally using flap splitting or Latzko techniques 7

General Gastrointestinal Fistulas

Anatomical Classification:

Fistulas classified by site of origin, site of openings, or as simple vs. complex 2

Physiologic Classification:

• Low output: <200 mL/day
• Moderate output: 200-500 mL/day
• High output: >500 mL/day—most useful for non-surgical management planning 2

Etiologic Classification:

Postoperative trauma, inflammation, infection, malignancy, radiation injury, or congenital 2

Critical consideration: Mortality rates remain up to 30% due to complications including sepsis, fluid/electrolyte disturbances, and malnutrition—requiring aggressive multidisciplinary management 2