Fistula
Classification, clinical presentation, and diagnostic workup
- Anatomical Classification of Digestive and Perineal Fistulas. Anorectal fistulas (most common in clinical practice): path between the anal canal or rectum and the perineal skin (anoperineal or anorectal fistula) — Parks classification by relation to the anal sphincter: intersphincteric (70 % — path between the internal and external sphincters) + transsphincteric (25 % — traverses the external sphincter) + suprasphincteric (5 % — passes above the external sphincter) + extrasphincteric (rare — entirely bypasses the sphincter complex) — transsphincteric and suprasphincteric fistulas are the most surgically complex (risk of postoperative anal incontinence if the sphincter is severed); enterocutaneous fistulas (ECF): communication between the digestive tract (small intestine or colon) and the skin — classification by output: low output <200 ml24h (souvent côlon ou iléon distal) + moyen débit 200–500 haut>500 mL/24h (proximal jejunum - risk of undernutrition + severe hydro-electrolytic disorders) - causes: post-surgical complications (50-75 % of ECF - faulty anastomosis + accidental intestinal wound + surgical foreign body) + Crohn's disease + complicated diverticulitis + neoplasia + pelvic irradiation; entero-enteric fistulas : communication between two digestive tracts - often asymptomatic if between non-functional segments - problematic if short-circuiting a useful segment (ileo-sigmoid in Crohn's disease - diarrhea + malabsorption); genitourinary fistulas: vesicovaginal (bladder-vagina communication - permanent total urinary incontinence + absence of micturition urgency - vaginal methylene blue test) + ureterovaginal + rectovaginal (rectum-vagina communication - emission of gas or matter through the vagina + recurrent infections); broncho-pleural and tracheo-oesophageal fistulas: post-pneumonectomy complications + severe pulmonary infections (TBC) + congenital malformations (TEF - tracheo-oesophageal fistula); arteriovenous fistulas (AVF): acquired (trauma + iatrogenic - vascular access for haemodialysis) + congenital - distinct from digestive fistulas by their vascular nature.
- Main etiologies and predisposing factors: infectious and inflammatory causes: undrained or inadequately drained perianal abscess → anal fistula (most frequent mechanism - Parks' cryptoglandular theory: infection of an anal gland in the intersphincteric space → abscess → extension → fistulization) + Crohn's disease (perineal fistulas are present in 25-40 % of Crohn's diseases - often complex + recurrent + refractory) + intestinal tuberculosis (important cause in high prevalence countries + Quebec migration) + abdomino-actinomycosis (characteristic skin fistulas) + complicated sigmoid diverticulitis (colovesical fistula - pneumaturia + fecaluria) + infected Bartholin's disease (vulvar fistula); iatrogenic and post-surgical causes: anastomotic fistula after digestive resection (dehiscence of anastomosis) + accidental wounding of the ureter during hysterectomy (ureterovaginal fistula) + rectal injury during pelvic surgery (rectovaginal fistula) + mesh prosthesis fitting (foreign body maintaining fistula); obstetrical causes: prolonged delivery with head down → vesicovaginal or rectovaginal pressure necrosis (obstetric fistula - a major public health problem in countries with limited resources - rare in Quebec thanks to access to obstetric care) + poorly repaired 4th degree tear + complicated episiotomy → rectovaginal fistula; neoplastic causes: tumoral invasion of the digestive or urinary walls + spontaneous fistulization of colorectal cancer + post-radiotherapy pelvic radionecrosis (cervical, prostate, rectal cancer) → radiation-induced rectovaginal or colovesical fistula; factors favoring spontaneous non-closure (acronym FRIENDS): foreign body (prosthesis + non-resorbable suture) + previous irradiation + active infection + epithelialization of the tract + neoplasia + distal obstruction + short tract Under 2 cm
- Diagnostic assessment of fistulas — imaging and endoscopy: anal fistula: clinical examination (external cutaneous orifice + palpation of the path + internal orifice on anoscopy according to Goodsall's rule: posterior external os → medial posterior internal os + anterior external os → direct path to nearest internal os) - perineal MRI with gadolinium (gold standard for complex anal fistulas + Crohn's disease - Parks classification + location of secondary tracts + associated abscesses + relationship to sphincter) - endoanal ultrasonography (360° rotating transducer - good performance for intrasphincteric fistulas + less reliable for trans- and supra-sphincteric fistulas) - fistulography (injection of product into fistulas - good performance for intrasphincteric fistulas + less reliable for trans- and supra-sphincteric fistulas) - fistulography (injection of product into fistulas)fistulography (injection of contrast medium into the external orifice) : less and less used (replaced by MRI) + useful if MRI unavailable + can be combined with CT-fistulography (CT + contrast); enterocutaneous fistula : abdominal-pelvic CTwith IV contrast + oral (delimits collections + assesses extent + looks for distal obstruction + neoplasia) + skin fistulography (injection of Gastrografin - water-soluble - into skin orifice) + small bowel transit by enteroscopy if Crohn's + abdominopelvic MRI if Crohn's disease (assessment of inflammatory activity) + nutritional work-up (albumin + prealbumin + CBC + ionogram + magnesium + phosphorus) - essential, as malnutrition is a major factor in non-healing.healing ; vesicovaginal fistula : cystoscopy (visualizes vesical orifice + biopsies if neoplasia suspected) + intravesical methylene blue test (stains vagina if fistula) + IV urography or uro-scanner (excludes ureteral involvement) + retrograde urethro-cystography + vaginoscopy; rectovaginal fistula: gynecological examination + digital rectal examination + sigmoidoscopy (visualizes rectal orifice + biopsies) + pelvic MRI + opaque transit if neoplasia suspected.
Treatment of Major Fistulas
| Type of fistula | Therapeutic options and surgical techniques | Results, complications, and specific management |
|---|---|---|
| Simple anal fistula Low intersphincteric - transsphincteric |
Simple anal fistula (intersphincteric or low trans-sphincteric crossing less than 30-50 % of the external sphincter) is treated surgically with an excellent cure rate and low risk of incontinence; fistulotomy (flattening of the fistula): reference technique for simple fistulas - incision and marsupialization of the entire fistulous tract - under local anesthesia + sedation or general anesthesia on an outpatient basis - flattening of the tract + curettage of the epithelium + daily dressings until healing by second intention (4-8 weeks) - cure rate : 85-95 % - incontinence rate: 30 % remaining); seton drain before fistulotomy: indication: high trans-sphincteric fistula or doubt about the amount of sphincter involved - silicone or nylon thread passed through the tract + loosely knotted around the sphincter → drainage of sepsis → progressive fibrosis → reduction of incontinence risk by progressive sectioning of the sphincter (cutting seton - Hippocrates technique) or preparation for definitive treatment (draining seton without sectioning) - duration: 2-6 weeks + then definitive treatment according to surgical assessment; mucosal advancement (advancement flap): flap of rectal mucosa slid to cover internal orifice - total sphincter preservation - healing rate 70-80 % - preferred option for high trans-sphincteric fistulas in patients with fragile sphincter (women + elderly patients + Crohn's); LIFT (ligation of intersphincteric fistula tract): ligation and section of intersphincteric tract - access via incision in intersphincteric space - total sphincter preservation - cure rate 60-80 % - no risk of incontinence - increasingly popular option for simple trans-sphincteric fistulas | Post-operative fistulotomy care: sitz baths 2-3/d (warm water 36-37°C × 15 min) + daily dressings + high-fiber diet + osmotic laxatives (PEG - Restoralax) for regular soft stools + acetaminophen + NSAIDs for pain + weekly surgical follow-up for the first 4 weeks; complications of fistulotomy: anal incontinence (most feared risk - function of % of sphincter severed) + recurrent abscess + fistula recurrence (10-20 % at 5 years) + delayed healing (radiation history + Crohn's disease + diabetes + smoking + immunosuppression); anal fistula and Crohn's disease - specific approach: 1st-line medical treatment prior to surgery: control of inflammatory bowel activity (mesalazine + immunosuppressants + biotherapies) + healing with immunosuppressants (azathioprine + 6-mercaptopurine) + infliximab (Remicade) : closure rate at 54 weeks 36 % vs 19 % placebo (ACCENT II - Sands 2004) + adalimumab (Humira): similar data - prolonged draining seton + sepsis control prior to biotherapy (never start anti-TNF biotherapies in the presence of an undrained active abscess) + fistulotomy: avoided if Crohn's disease is active or the fistula is complex (risk of chronic non-healing perineal wounds) + low-teton flow if long-term medical treatment is inadequate; other emerging surgical techniques: biological glue (fibrin) : injection into the fistulous tract - closure rate 50-80 % for simple fistulas - less effective for complex fistulas + fistula plug (biological plug made of porcine mucin or synthetic): inserted into the tract after curettage - closure rate 50-70 % - advantage : total sphincter preservation - frequent long-term recurrence; stromal stem cells (Cx601 - darvadstrocel - Alofisel): EMA 2018 approval for complex perineal fistulas in Crohn's disease - local injection of stem cells derived from autologous adipose tissue - clinical and radiological cure rate 51.5 % vs 35.6 % placebo (ADMIRE-CD - Panés 2016) - available in France + Europe - not commercially available in Canada to date |
| Enterocutaneous fistula (ECF) Mandatory initial medical care |
Enterocutaneous fistula is one of the most feared complications of abdominal surgery - its mortality remains significant (5-25 % depending on series) mainly due to sepsis and severe undernutrition; initial management - SOWATS principle (Stabilization + Optimization + Wound care + Anatomy + Timing + Surgery): stabilization (phase 1 - weeks 1-2) : sepsis control (drainage of collections + targeted antibiotic therapy if documented) + hydroelectrolytic resuscitation (high-flow fistulas can cause severe hypokalemia + hyponatremia + hypomagnesemia) + perifistula skin protection (stomotherapy - fistula appliance to reduce skin damage and measure flow); artificial nutrition - mainstay of treatment: total parenteral nutrition (TPN): indicated if high-flow fistula (>500 mL/24h) + impossibility of sufficient enteral nutrition + severe undernutrition - goal: 25-35 kcal/kg/d + 1.5-2 g/kg/d protein - resting the digestive tract → reducing fistula flow - nutritional assessment: albuminemia + prealbuminemia + CRP + CBC + ionogram + zinc + magnesium + phosphorus + B12 + folates + fat-soluble vitamins; enteral nutrition (if flow <200 mL/24h + enteral approach possible): nasojejunal tube downstream of fistula or direct enteral feeding tube - fewer infectious complications than TPN + better preservation of intestinal mucosa; flow reduction: proton pump inhibitors (PPIs - omeprazole 40 mg/d IV or PO) - reduced gastric and pancreatic secretions → reduced fistula flow - somatostatin analog (octreotide 100-300 µg SC × 3/d or lanreotide monthly deep injection): reduces digestive secretions by 30-50 % + potentially accelerates spontaneous closure (controversial data - divergent meta-analyses); wound care: perifistular VAC (vacuum-assisted closure) dressing + stomatherapist + protection of perifistular skin with zinc paste or ostomy powder | Spontaneous closure and surgical timing: spontaneous closure expected in 25-40 % of ECFs under optimal medical treatment - delay: 4-6 weeks - factors favorable to spontaneous closure: low flow + long trajectory + absence of FRIENDS factors + good nutrition + absence of foreign body; surgery if non-closure at 6-8 weeks under optimal medical treatment or if FRIENDS factors identified: surgical timing (the «6-month rule»): in non-urgent situations, wait at least 3-6 months after initial surgery to allow resolution of inflammation + nutritional restoration + lysis of intra-abdominal adhesions - operate too early = almost certain recurrence; surgical principles: resection of intestinal segment bearing fistula + anastomosis (if bowel in good condition) or temporary stoma (if inflammation + undernutrition + precarious terrain) + closure of skin orifice; post-operative nutrition: maintenance of artificial nutrition until correct oral re-feeding + transit monitoring; negative pressure therapy (VAC therapy) in directed wound healing: may promote closure of certain low-flow ECFs + improves quality of perifistular skin healing; ECF and Crohn's disease: anti-TNF biotherapies (infliximab + adalimumab) before surgery to control inflammation + Crohn's fistula generally does not close without intensive medical treatment → surgical resection if refractory with maximal intestinal sparing (risk of short small bowel); ECF mortality: poor prognostic factors → uncontrolled sepsis + severe undernutrition (albumin <20 g/L) + high-flow proximal small bowel fistula + anterior radiation + underlying neoplasia |
| Vesicovaginal fistula Total urinary incontinence — reconstructive surgery |
Vesicovaginal fistula (VVF) is the most common genitourinary fistula in industrialized countries - it causes permanent total urinary incontinence (continuous urine leakage through the vagina), profoundly disabling; causes in the Quebec context: gynecological surgery (hysterectomy - most frequent cause in developed countries - bladder injury or pressure necrosis) + pelvic radiotherapy (cervical + endometrial + rectal cancer - late radiation fistula: 1-10 years after irradiation) + traumatic childbirth (tear + forceps) + invasive gynecological cancer; clinical presentation: permanent total urinary incontinence (continuous urinary leakage without effort or urgency) + absence of urine in the bladder (permanent emptying of the fistula) + recurrent urinary tract infections + persistent urinary odor + major psychosocial and sexual morbidity; diagnosis: intravesical methylene blue test (stained vaginal swab → vesicovaginal fistula confirmed) + cystoscopy (visualizes and biopsies the vesical orifice) + uro-scanner or URO-MRI (excludes associated ureteral involvement - concomitant ureterovaginal in 12 % of post-surgical VVFs); spontaneous closure: possible in small (<1 cm) VVFs detected early (<7-10 days post-surgery) with bladder catheter in continuous drainage × 4-6 weeks - spontaneous closure rate: 10-15 %; surgical treatment of VVF: timing: wait 3-6 months after surgery or causative irradiation to allow resolution of local inflammation (with the exception of fistulas detected within 48-72h post-op which can be repaired immediately) - approach: vaginal (Latzko route - a technique of unlevelling by excision and layered closure without resection of the tract - 1st intention for most VVFs) or abdominal (laparotomy or laparoscopy - if high fistula + close to the ureters + post-radiation fistula + recurrence after vaginal route); interposition of Martius flap (large vulvar lip): between bladder and vaginal layer to provide additional vascularization + reduce risk of recurrence - particularly useful in radiation fistulas | Results of vesicovaginal fistula surgery: cure rate: vaginal route (Latzko): 85-95 % at 1st attempt in simple post-surgical VVF - abdominal route: 80-90 % (more complex indication) - radiation fistula: poorer results (70-80 %) + high risk of recurrence + reinforcement vascular flap essential; post-operative complications: post-repair stress urinary incontinence (10-20 % - fistula closure sometimes unmasks underlying sphincter insufficiency → urethroplasty or secondary suburethral sling if necessary) + vaginal stenosis (radial fistulas) + recurrence (5-15 % depending on etiology); post-radial vesicovaginal fistula - specifics: poorly vascularized + fragile radial tissue → imperative need for vascular supply (Martius flap + gracilis or greater omentum flap depending on extent of necrosis) + avoid needle in radial tissue → use of slow resorption sutures + colpocleisis (complete vaginal closure) in very severe cases in women without an active sex life; Quebec reference centers for pelvic reconstructive surgery: CHUM + Hôtel-Dieu de Montréal (reconstructive urology) + CHU de Québec (urology + gynecology) + Royal Victoria Hospital (MUHC) + waiting times in the public sector: 6-18 months + private sector: faster + variable complementary insurance coverage |
| Rectovaginal fistula Vaginal gas/discharge |
Rectovaginal fistula (RVF) is an abnormal communication between the rectum or anal canal and the vagina - it causes disabling symptomatology: emission of gas + faeces through the vagina + recurrent vaginal and urinary infections + perineal pain + dyspareunia + major impact on quality of life and sexuality; anatomical classification of RVFs: low level (anovaginal): communication between anal canal and vagina → most frequent cause: obstetric (poorly repaired 4th degree tear + Bartholin's gland abscess) + medium level: between lower rectum and lower third of vagina → Crohn's + pelvic surgery + high level: between middle rectum and vaginal fundus → pelvic surgery + neoplasia + irradiation; main causes: obstetric (most frequent in low-income countries - rare in Quebec): insufficiently repaired 3rd- or 4th-degree perineal tear + instrumental extraction + fetal macrosomia - Crohn's disease (most frequent cause in developed countries for recurrent complex RVF - 3-10 % of Crohn's patients) - post-surgical (low colorectal anastomosis - anterior rectal resection + hysterectomy) - post-radiation (cervical + rectal cancer) - diverticulitis + neoplasia; diagnostic workup: gynecological examination under valves (visualizes vaginal orifice + allows biopsy if neoplasia) + digital rectal exam + rectoscopy or sigmoidoscopy (rectal orifice + biopsies) + perineal MRI (path + relationship to sphincter + inflammatory activity if Crohn's) + anorectal manometry (continence assessment before surgery - important as repair may require cutting sphincter → risk of incontinence); conservative treatment: drainage + antibiotics if associated abscess + draining seton if Crohn's + biotherapies (infliximab + adalimumab) for Crohn's RVFs | Surgical options for rectovaginal fistula: repair by perineal route (low-level obstetric fistula): anterior sphincterography (repair of damaged anal sphincter) + rectal or vaginal advancement + results: 70-80 % cure rate on simple native obstetric valve + residual anal incontinence possible if sphincter damaged; transanal rectal advancement (advancement flap): reference technique for medium-level RVFs - rectal mucosa flap slid over rectal orifice - healing rate 70-80 % after 1st attempt - indicated if sphincter intact + no active Crohn's + no previous radiotherapy; temporary bypass stoma (colostomy or ileostomy): resting the rectum before complex RVF repair - duration: 2-3 months prior to repair + stoma closure 3 months after successful repair - indicated if extensive + post-radiation FRV + active Crohn's + undernutrition + failure of prior repair; muscular interposition: gracilis muscle or greater omentum to provide additional vascularization between layers - particularly useful in radiation FRV (poorly vascularized radiation tissue); FRV and Crohn's disease: anti-TNF biotherapies in 1st line (infliximab + adalimumab - closure rate 30-50 % on biotherapy) + draining seton if active sepsis + surgical repair only if bowel disease controlled + persistent isolated LIF + after 3-6 months of biotherapy - ustekinumab + vedolizumab : emerging data in refractory Crohn's FRV; proctectomy and ileoanal pouch: ultima ratio in refractory Crohn's FRV with severe rectal disease + pre-existing severe anal incontinence |
| Arteriovenous fistula (AVF) for vascular access Dialysis — thrombosis — Doppler monitoring |
The native arteriovenous fistula (AVF) (direct anastomosis between an artery and a vein, without interposition of a prosthesis) is the reference vascular access for chronic hemodialysis - it is said to be «surgically created» unlike pathological fistulas - it is ideally placed 3-6 months before the planned start of dialysis (to allow maturation - dilatation + muscularization of the arterialized vein); types of native AVF: Brescia-Cimino radiocephalic (wrist - radial artery + cephalic vein): reference technique - longest duration of patency - lowest incidence of complications + brachiocephalic (elbow): 2nd choice if cephalic wrist vein inadequate + brachio-basilic (transposed basilic arm vein): more complex - requires surgical transposition of deep vein + prosthetic AVF (PTFE - polytetrafluoroethylene): if insufficient venous capital; complications of hemodialysis AVFs: thrombosis (most frequent - 80-85 % of AVFs thrombose in the first 2 years) → surgical thrombectomy or endovascular thrombolysis (tPA) + angioplasty if triggering stenosis → short intervention time (optimal rescue if <24-48h from thrombosis) - drainage vein stenosis (most frequent cause of dysfunction - detected by drop in dialysis flow + increase in venous pressures) → echodoppler then percutaneous angioplasty (PTA) + surgical recanalization if unsuccessful ; steal syndrome: bypass of blood flow from distal arteries to AVF → hand ischemia (pain + pallor + numbness + paralysis in severe forms) → surgical correction (DRIL - distal revascularization and interval ligation); prosthetic AVF infection: Staphylococcus aureus + Staphylococcus epidermidis + gram-negative → prolonged IV antibiotics + partial or total resection of the prosthesis if infection uncontrolled; distal venous hypertension + pseudoaneurysm (saccular dilatation of the vein dialyzed by repeated punctures) → risk of rupture → surgical repair or ligation | Monitoring and maintenance of the hemodialysis AVF: clinical monitoring at each session: auscultation of thrill + palpation of quivering + examination of the skin above the AVF + dynamic venous pressure + dialysis flow rate + Kt/V (adequacy marker); monitoring echodoppler: recommended every 6-12 months (or if clinical dysfunction detected) → flow measurement (native AVF: target >500-600 mL/min + prosthetic AVF: target >600-800 mL/min) + detection of early stenosis + assessment of maturation of a new AVF (flow >500 mL/min + venous diameter >6 mm at 6 weeks = maturation criteria); dialysis patient self-monitoring: teach the patient to palpate the AVF daily (quivering present = patent AVF) → consult immediately if the quivering disappears (acute thrombosis) or if pain + redness + heat (infection) + do not sleep on the side of the AVF + avoid taking blood pressure + taking blood samples + placing infusions on the arm of the AVF + mechanical protection of the AVF if activities at risk of trauma; AVF and temporary central venous access (CVC): the CVC is used while waiting for a new AVF to mature, or during complications - high risk of S. aureus bacteremia. aureus bacteremia (×7 vs. native AVF) + risk of central vein stenosis (subclavian vein ++) → justification for preferential use of native AVF as soon as possible as part of the pre-dialysis program; IUGR coordination in Quebec: every patient reaching a GFR <15-20 mL/min → referral to vascular surgeon for AVF creation + coordination with nephrologist + CHU pre-dialysis program + waiting times for AVF creation in public vascular surgery: 2-6 months depending on region |
Perianal abscess + throbbing pain + fever + progressive perineal cellulitis → Undrained abscess progressing to Fournier's gangrene → Surgical emergency → Immediate wide debridement.
High-output enterocutaneous fistula (>500 mL/24h) + fever + hypotension Sepsis on fistula with acute malnutrition -> hospitalization, resuscitation, PN, surgical drainage if collection.
AV fistula + disappearance of thrill Acute thrombosis → vascular emergency → thrombectomy within 24–48 hours to save access.
Vesicovaginal fistula + fever + flank pain + anuria → ureteral obstruction associated → urgent uro-scan → emergency ureteral drainage.
Consult at Clinique Omicron
The doctors at Clinique Omicron evaluate patients presenting with symptoms suggestive of a fistula (persistent discharge + passage of gas or stool through an abnormal tract + chronic perineal pain), prescribe the initial diagnostic workup, and refer to the appropriate colorectal surgeon, urologist, gynecologist, or vascular surgeon depending on the nature of the fistula. Nutritional management of enterocutaneous fistulas and follow-up of Crohn's disease fistulas under biotherapy are provided in coordination with specialized teams. Consultations are available at several service points in Quebec and via telemedicine. To make an appointment, visit cliniqueomicron.ca.
The content of this page is provided for informational purposes only and does not substitute for the advice of a qualified surgeon or specialist. The management of complex fistulas requires individualized specialized evaluation.
Omicron Clinic
Need to consult a doctor?
Treatment within 24-48 hours. In-clinic or telemedicine, anywhere in Quebec.
Insurance receipts. 7j/7. No family doctor required.