Management of Fistula
Type-Specific Treatment Approach
The appropriate treatment depends critically on fistula type and location—management differs fundamentally between vascular access fistulae, perianal/anorectal fistulae, enterocutaneous fistulae, and enterovaginal fistulae.
Perianal/Anorectal Fistulae (Crohn's Disease and Non-IBD)
Emergency/Acute Presentation
If a patient presents with perianal abscess, drain the abscess adequately under general anesthesia without actively searching for an associated fistula. 1 Probing for a fistula during acute abscess drainage can create iatrogenic tracts and significantly complicate future management. 1
If an obvious fistula is visible without probing, insert a loose draining seton—do not lay the fistula open. 1 The seton should be low-profile, made of soft material (avoid nylon), and have no bulky knots to preserve future anal function. 1
Wound packing is not routinely required after abscess drainage, except for short-term hemostatic needs. 1
In the emergency setting, there is no role for surgical adjuncts to fistula healing (fibrin glue, fistula plug, LIFT, advancement flap, VAAFT, FiLac, stem cells) when sepsis is present. 1
Elective Management of Established Fistulae
Surgery should only be attempted in symptomatic patients with no concomitant abscess, medically controlled proctitis, and preferably an anatomically defined fistula tract. 2
Surgical Options by Fistula Complexity:
Simple/superficial fistulae: Fistulotomy (laying open the tract) is appropriate for subcutaneous, superficial, or low intersphincteric fistulae in the lower third of the sphincter. 2 Contraindications include Crohn's Disease Activity Index >150 or evidence of perineal Crohn's involvement. 2
Complex fistulae: Loose setons are the primary drainage method, minimizing risk of future abscesses and facilitating hygiene. 2 When combined with optimal medical therapy, setons can be definitive treatment, with removal achieved in up to 98% of patients at a median of 33 weeks. 2
Moderate to severe proctitis: Seton placement is the only sensible surgical option; medical therapy must be commenced to treat proctitis before any definitive repair. 2
Medical Therapy for Perianal Fistulae
Maintenance therapy should include thiopurines, infliximab, or adalimumab, either alone or combined with seton drainage. 2 Medical therapy to control disease-related inflammation is imperative to increase the likelihood of tract healing after surgery. 2
Clinical assessment (decreased drainage) is usually sufficient to evaluate treatment response in routine practice. 2
MRI or anal endosonography combined with clinical assessment is recommended to evaluate improvement of fistula tract inflammation. 2
Patients refractory to medical treatment should be considered for diverting ostomy, with proctectomy as the last resort. 2
Special Fistula Types:
Asymptomatic low anal-introital fistulae: Do not require surgical treatment. 2
Symptomatic rectovaginal fistulae: Surgery is usually necessary, including possible diverting ostomy. 2 Active Crohn's disease with rectal inflammation should be treated medically before and after surgery to prevent recurrence. 2
Entero-enteric and entero-vesical fistulae: Often require resective surgery, strongly recommended if associated with abscess, bowel stricture, or causing excessive diarrhea and malabsorption. 2
Anal Fissure (Not a Fistula, but Often Confused)
Initial Management
Increase fiber intake and ensure adequate fluid consumption as first-line treatment—approximately 50% of acute anal fissures heal within 10-14 days with conservative management alone. 3, 4
Apply topical anesthetics (lidocaine) directly to the fissure for pain management. 3, 4
Add oral analgesics (paracetamol) if topical agents provide inadequate relief. 3, 4
Warm sitz baths promote sphincter relaxation. 4
Pharmacological Treatment for Persistent Fissures
If no improvement after 2 weeks, use topical calcium channel blockers (0.3% nifedipine with 1.5% lidocaine) applied three times daily for at least 6 weeks, achieving 65-95% healing rates. 3, 4 Pain relief typically occurs after 14 days of treatment. 3, 4
- Glyceryl trinitrate ointment is an alternative with 25-50% healing rates, though headaches are common. 3
Surgical Intervention
Reserve surgery for fissures that don't respond after 8 weeks of non-operative management—lateral internal sphincterotomy is the gold standard surgical procedure. 3, 4
Critical Pitfalls to Avoid:
Manual dilatation is strongly contraindicated due to high risk of temporary and permanent incontinence. 3, 4
Surgical treatment should not be performed for acute anal fissures. 3, 4
Botulinum toxin injection has no established role in acute fissure management. 3
Vascular Access Fistulae (Hemodialysis)
Monitoring and Surveillance
Implement an organized monitoring program with regular assessment of clinical parameters and hemodialysis adequacy. 5 Physical examination should be used to detect dysfunction in fistulae. 5
Evaluate patients no later than 6 weeks after access placement to detect early dysfunction, particularly delays in maturation. 5
Persistent swelling of the hand or arm should be expeditiously evaluated and the underlying pathology corrected. 5
Indications for Intervention
Intervene on a fistula for inadequate flow to support prescribed dialysis blood flow, or aneurysm formation in a primary fistula. 5
A fistula with >50% stenosis in venous outflow or arterial inflow, combined with clinical or physiological abnormalities, should be treated with PTA or surgical revision. 5 Abnormalities include reduced flow, increased static pressures, access recirculation, or abnormal physical findings. 5
Prophylactic PTA of stenosis in functioning forearm fistulae improves access survival and decreases access-related morbidity, halving the risk for hospitalization, central venous catheterization, and thrombectomy. 5
Thrombosis Management
Thrombectomy should be attempted as early as possible after thrombosis is detected, but can be successful even after several days. 5
Infection Management
Infections of primary AVFs are rare and should be treated as subacute bacterial endocarditis with 6 weeks of antibiotic therapy. 5 Fistula surgical excision should be performed in cases of septic emboli. 5
Ischemia Assessment
Assess patients with an AVF regularly for possible ischemia. 5
Patients with new findings of ischemia should be referred to a vascular access surgeon emergently. 5
Enterocutaneous/Enteroatmospheric Fistulae
Initial Non-Operative Management
A non-operative approach is generally accepted as the initial approach, especially in the acute/subacute setting. 6 Successful management requires a multidisciplinary team including gastroenterology, surgery, nutrition support, and wound/ostomy care. 7, 6, 8
Key Components:
Optimize nutritional status: All nutritional support can usually be provided via the enteral route for distal fistulae with low output. 7 For high-output fistulae, provide partial or exclusive parenteral nutrition with increased caloric intake and protein demands. 7
Establish source control: If abscess is present, treat with IV antibiotics and radiological drainage initially, with surgical drainage reserved for cases where necessary. 7 Anti-TNF therapy should only be started after abscesses have been treated with antibiotics and drainage. 7
Delineate fistulous tract anatomy: CT abdomen/pelvis with IV contrast is the preferred initial imaging modality (76.5% sensitivity for fistula detection, 94.1% for defining etiology). 7 Use water-soluble contrast (not barium) placed in the bowel to opacify the fistulous tract. 7
Skin care and containment: Effective pouching systems are critical for high-output fistulae to preserve skin integrity and patient comfort. 8, 9
Surgical Intervention
Operative intervention is indicated in the setting of failed non-operative management. 6 Do not attempt surgical repair in the presence of active sepsis or undrained abscess, as this significantly increases failure rates. 7
Primary closure of both intestinal and vaginal defects (for enterovaginal fistulae) should be performed in separate layers, with interposition of healthy tissue to prevent recurrence. 7
Avoid using synthetic mesh as a fascial bridge in contaminated fields, as this induces adhesions, erosions, and fistula formation. 7
Preemptive measures to prevent recurrence include early abdominal wall closure, bowel coverage with plastic sheets or omentum, and no direct application of synthetic prosthesis over bowel loops. 7
Common Pitfalls Across All Fistula Types
Never probe aggressively for fistulae in the acute/emergency setting—this creates iatrogenic tracts and complicates management. 1
Do not attempt definitive fistula repair in the presence of active sepsis, undrained abscess, or uncontrolled inflammation. 2, 7
Avoid manual dilatation for anal fissures (often confused with fistulae)—permanent incontinence risk is unacceptably high. 3, 4
Do not rely on clinical examination alone to confirm fistula healing—use imaging (MRI or endosonography) to verify tract resolution. 2, 7