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Operative management of anorectal fistulas

Operative management of anorectal fistulas
Literature review current through: Jan 2024.
This topic last updated: Oct 27, 2023.

INTRODUCTION — An anorectal fistula (also called fistula-in-ano) is an inflammatory tract or connection between the epithelialized surface of the anal canal and, most frequently, the perianal skin or perineum. It often evolves from a spontaneously draining anorectal abscess. Perianal fistulous disease has significant implications for patient quality of life as sequelae range from minor pain and social hygienic embarrassment to frank sepsis.

Surgery is the mainstay of therapy with the ultimate goal of draining local infection, eradicating the fistulous tract, and avoiding recurrence while preserving native sphincter function [1,2]. The surgical approach depends on several factors, such as the etiology, location, type, and duration of the fistula, as well as previously performed procedures and preoperative sphincter function.

This topic will discuss the surgical management of anorectal fistulas. The causes, clinical manifestations, diagnosis, and classification of anal fistulas are discussed elsewhere. (See "Anorectal fistula: Clinical manifestations and diagnosis" and "Perianal Crohn disease".)

ANORECTAL ANATOMY — A thorough knowledge of the anatomy of the anal canal, ischiorectal fossa, perirectal tissues, and sphincteric muscles is imperative before proceeding with any operative procedure to treat an anorectal fistula [3-5].

Anal mucosa and crypts – The upper part of the anal canal is lined by mucosa similar to the rectum, while the lower portion is lined by stratified epithelium similar to the skin of the perianal region. The line around the anal canal that can be traced by following the anal columns is the pectinate line (also called the dentate line or mucocutaneous line) (figure 1). This line represents the change in epithelium as well as lymphatic drainage, blood supply, and venous drainage. The pectinate line is palpated or visualized approximately 2 cm above the anal opening.

At the junction of these two types of lining are the anal columns, longitudinal and wider at the distal end, while fading at the proximal end of the canal. They are united distally by thin membranes called anal valves. Between the bases of the longitudinal columns and the anal valves are anal sinuses, rudimentary anal glands (also called crypts or ducts), which open into the anal sinuses (figure 1). An infection of an anal sinus and gland can develop into an abscess. The abscess develops a fistula that can extend from the anal canal into the perianal musculature, the ischiorectal fossa, and the skin.

Anal canal – The anal canal begins at the anorectal junction and ends at the anal verge (figure 1 and figure 2). The anal verge is demarcated at the site where the squamous epithelium lining of the lower anal canal becomes continuous with the skin of the perineum.

Anteriorly, the middle third of the anal canal is attached by dense connective tissue to the perineal body, which separates it from the membranous urethra and penile bulb in males and from the lower vagina in females.

Laterally and posteriorly, the anal canal is surrounded by loose adipose tissue within the ischiorectal fossas.

Posteriorly, the anal canal is attached to the coccyx by the anococcygeal ligament, a midline fibroelastic structure that may possess some skeletal muscle elements and that runs between the posterior aspect of the middle portion of the external sphincter and the coccyx. Just above this is the raphe of the levator ani muscle, the fusion of the two halves of iliococcygeus, which merges anteriorly with the puborectalis muscle.

Ischiorectal fossa – The ischiorectal fossa is triangular in shape and bounded by the skin inferiorly, the obturator internus muscle laterally, and the inferior surface of the levator ani as its anterior and medial border (figure 3 and figure 4).

Posteriorly, the ischiorectal space is continuous to the sacrotuberous ligament and the gluteus maximus muscle with the potential space in the buttock deep to the muscle. The left and right ischiorectal fossas communicate above a portion of the external anal sphincter that extends posteriorly to attach to the coccyx.

Superiorly, the ischiorectal fossa is sealed off by the origin of the levator ani from the inner surface of the obturator internus and the continuity of the inferior fascia of the pelvic diaphragm with the obturator fascia.

Anteriorly, the ischiorectal fossa is separated from the superficial perineal space by the attachment of the perineal fascia to the posterior border of the urogenital diaphragm. The ischiorectal fossa continues forward for a short distance above the urogenital diaphragm and the lower border of the pelvic diaphragm until these two diaphragms join.

Internal anal sphincter – The internal anal sphincter is a well-defined ring of obliquely orientated smooth muscle fibers that is continuous with the circular muscle of the rectum and terminates at the junction of the superficial and subcutaneous components of the external sphincter (figure 1). The lower portion of the sphincter is crossed by fibers from the conjoint longitudinal tendon that pass into the submucosa of the lower canal.

External anal sphincter – The external anal sphincter is an oval, tube-shaped complex composed mainly of skeletal muscle fibers. The muscle consists of deep, superficial, and subcutaneous parts but should be considered as a single functional and anatomical entity (figure 1).

The uppermost fibers of the external anal sphincter blend with the lowest fibers of puborectalis muscle. The fibers from the upper third attach anteriorly into the superficial transverse perineal muscles, and posteriorly the fibers are attached to the anococcygeal raphe. The majority of the fibers of the middle third of the external anal sphincter surround the lower part of the internal sphincter. The middle third is attached anteriorly to the perineal body and posteriorly to the coccyx by the anococcygeal ligament. The fibers of the lower third of the muscle lie below the level of the internal anal sphincter and are separated from the lowest anal epithelium by the submucosa layer.

The transverse perinei and bulbospongiosus muscles fuse with the external sphincter in the lower part of the perineum. The perineal body attaches the external anal sphincter muscle to the surrounding structures and is an imbrication of muscle fibers in females in comparison to a central tendinous insertion in men. Also, in females, the anterior and lateral portion of the external anal sphincter is significantly shorter and is oriented in a horizontal plane. In males, the external sphincter is more anular and is separate from the central point of the perineum, so that there is a surgical plane of cleavage between the external sphincter and perineum [6].

Goodsall rule – One of the most commonly cited principles to assist in the surgical management of an anal fistula is the Goodsall rule, which states (figure 5) [7]:

All fistula tracks with external openings within 3 cm of the anal verge and posterior to a line drawn through the ischial spines travel in a curvilinear fashion to the posterior midline.

All tracks with external openings anterior to this line enter the anal canal in a radial fashion.

Fistula tracks longer than 3 cm from the anal verge do not necessarily follow the Goodsall rule; they often have an internal opening in the posterior midline. Although the Goodsall rule is often quoted, it may not always be accurate. In general, it is thought to be more accurate for anterior fistulas than for posterior ones [8].

PREOPERATIVE PREPARATION

Patient preparation – In our practice, patients are advised to maintain a clear liquid diet for 24 hours prior to surgery and take two enemas the morning of surgery, if tolerated. We also advise patients to discontinue all drugs that can prolong bleeding (eg, aspirin-containing medications, nonsteroidal anti-inflammatory drugs). A mechanical bowel preparation is only required for patients undergoing a planned simultaneous sphincter reconstruction or extensive rotational flap.

Antibiotics – The benefit of preoperative antibiotics has not been established for anorectal surgery because of a low rate of surgical site infection [9]. In author's practice, broad-spectrum antibiotics are administered intravenously before the start of the procedure. Other surgeons may reasonably choose to omit prophylactic antibiotics in routine elective cases. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults".)

Anesthesia – The choice of anesthetic is determined by the preference of the patient and surgeon and the general medical condition of the patient. Options include a general anesthetic or locoregional anesthesia, such as a four-quadrant pudendal nerve block with 0.25% bupivacaine. Most patients will do well with a local anesthetic supplemented with intravenous medication for a light sedation. At the conclusion of the procedure, local injection of a long-acting local anesthetic provides several hours of comfort after the procedure. (See "Subcutaneous infiltration of local anesthetics" and "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications".)

Patient position – Appropriate positioning facilitates visualization of the internal opening.

Lithotomy – The lithotomy position is the preferred position for patients with a posterior external opening and when performing advancement flaps, ligation of the intersphincteric fistula tract procedures, and diversions.

Prone – Patients with anterior external openings, Crohn disease, and most patients with obesity are positioned in the prone jackknife position [1].

STAGED APPROACH — In our practice, all patients suspected of a fistula first undergo an examination under anesthesia to diagnose the fistula and to determine whether the fistula is simple or complex based on the extent of anal sphincter muscle involvement and other characteristics of the fistula. (See 'Definitive fistula repair' below.)

Clinical experience has shown that fistulotomy is an effective procedure for simple submucosal, intersphincteric, and low-sphincteric fistulas, while staged procedures are a better approach for complex fistulas [10]. Any staged repair of the fistula takes place approximately six weeks after the examination under anesthesia/draining seton placement. The procedure selection depends on the location of the fistula in relation to the external anal sphincter (Parks' classification) and the amount of the sphincter complex involved with the fistulous tract (figure 6).

Examination under anesthesia and seton placement — The purposes of this initial operation are to identify the external and internal opening, the course of the track, and the amount of sphincter muscle it incorporates. For complex fistulas, the insertion of a draining seton also ensures resolution of local sepsis before a definitive repair (often sphincter-sparing) is performed.

Identification of fistula track:

The anal canal is gently dilated digitally, the pectinate line is visualized, and the anal crypts are examined for evidence of inflammation and an internal opening.

A fistula probe is inserted into the external opening on the perianal skin and gently pushed toward the internal opening into the anus or rectum, using caution to avoid creating a false passage by penetrating the fistula wall.

If identifying the internal opening of the fistula track is not straightforward, many maneuvers have been devised to assist in this task. For example, instillation of dilute hydrogen peroxide into the external opening while performing anoscopy is often helpful to reveal the internal opening.

The Goodsall rule can be used to predict the trajectory of the track. (See 'Anorectal anatomy' above.).

Once the fistula probe exits the internal opening, the fistula track is established. Palpation of the anal canal, the fistula tract, and surrounding structures is performed to determine the amount of anal sphincter muscle involved (figure 7).

Draining seton insertion:

A suture is tied to the tip of the fistula probe to secure access to the track and can be used to deliver a seton through the track. A draining (or noncutting) seton is placed primarily for drainage [11]. It does not cut through the sphincter. Silastic vessel loops are the best material for draining setons. A yellow vessel loop is preferred to other colors for its size [12].

The ideal length of a draining seton is tight enough so as not to get in the way of bowel movements but loose enough not to erode through the skin (picture 1). Because the knot that secures the seton circle will inevitably enter the track, it should be as small as possible (two squared throws of the tie; cut the ends close to the knot for both the tie and seton) (picture 1). Patients with setons that are too small, too tight, too loose, too long, too numerous, or secured incorrectly can be miserable due to chronic irritation from the setons [12].

Until definitive surgical repair, a draining seton may be used to keep the fistula tract open, which often prevents recurrent abscess. Properly placed draining setons can be left in place indefinitely as long as they are effective in relieving symptoms, or they can be removed at the time of the definitive fistula repair with one of the following methods ≥6 weeks from the time of seton insertion. A draining seton can also be converted to a cutting seton by incising the skin bridge and subcutaneous tissue between the seton and sphincter muscle, allowing the seton to slowly migrate through the muscle over time. (See 'Cutting seton' below.)

Definitive fistula repair — The procedure selected for an individual patient should be based on a thorough physical examination of the anal region. No single operative technique is appropriate for the treatment of all anorectal fistulas; hence, the judgment and experience of the surgeon must guide the treatment decisions [8,10,13,14].

Simple fistulas — Most fistulas are simple (minimal involvement of the external sphincter muscle) and classified as low-lying transsphincteric (Parks' type 2 and involving <30 percent of anal sphincter complex) and intersphincteric fistulas (Parks' type 1) (picture 2) [1]. The traditional approach to treatment is primary fistulotomy [8]. Fistulotomy can be performed at the same time of the examination under anesthesia without the need for a draining seton or to wait for six weeks. (See 'Fistulotomy for simple fistulas' below.)

Complex fistulas — A complex fistula refers to those fistulas that have a high risk of treatment failure and cannot be safely treated by routine fistulotomy. An anal fistula is defined as complex in the following situations:

Any fistula involving more than 30 percent of the external sphincter

Suprasphincteric fistulas

Extrasphincteric or high fistulas, proximal to the dentate or pectinate line

Women with anterior fistulas

Fistulas with multiple tracts

Recurrent fistulas

Fistulas related to inflammatory bowel disease

Fistulas related to infectious diseases, including tuberculosis and HIV

Fistulas secondary to local radiation treatments

Patients with a history of anal incontinence

Rectovaginal fistulas (see "Rectovaginal and anovaginal fistulas")

Primary fistulotomy alone is inadequate treatment of complex fistulas because of the high risk of postoperative incontinence, so sphincter-sparing approaches are necessary [8,10,15]. Sphincter-sparing procedures include endoanal advancement flaps, fibrin glue, fistula plugs, the modified Hanley procedure, ligation of the intersphincteric fistula tract (LIFT), or diversion [10,16,17]. The choice of procedures is dictated by fistula anatomy as well as surgeon preference (algorithm 1):

High transsphincteric fistula — In our practice, we prefer to treat high transsphincteric fistulas (Parks' type 2 and involving >30 percent of the anal sphincter complex) with either an endoanal advancement flap or LIFT. We perform LIFT when the primary (internal) opening has migrated distal to the dentate line or if the patient has preexisting incontinence. When the primary opening is at the dentate line, either endoanal advancement flap or LIFT can be performed. (See 'Advancement flaps' below and 'Ligation of the intersphincteric fistula tract' below.)

Suprasphincteric fistula — Suprasphincteric fistulas (Parks' type 3) should be treated with endoanal advancement flaps. LIFT is not an option, because there is no intersphincteric fistula tract. (See 'Advancement flaps' below.)

Extrasphincteric fistula — Extrasphincteric fistulas (Parks' type 4) are typically not of cryptoglandular origin but are instead caused by cancer or Crohn disease. These fistulas are rare but difficult to treat. Surgical options include proctectomy or fecal diversion. (See 'Diversion' below.)

Horseshoe fistula — Horseshoe fistulas can be managed initially by drainage of the lateral sites with setons and a midline seton from the posterior primary opening to the deep postanal space. The lateral setons can be removed shortly after, and the primary opening can be managed by an endoanal flap or a cutting seton (ie, modified Hanley procedure). (See 'Modified Hanley procedure' below.)

Recurrent fistula — Recurrent fistulas that involve the sphincter complex typically warrant a pelvic magnetic resonance imaging (MRI) scan to clarify anatomy and a seton for drainage. Subsequently, they can be managed according to their classification as described above.

FISTULOTOMY FOR SIMPLE FISTULAS — Fistulotomy involves laying open the fistula tract in its entirety. It is an effective treatment for simple anal fistulas [18,19]. It is critical to assess all patients' incontinence score prior to fistulotomy. In patients with preexisting incontinence, fistulotomy is contraindicated in all situations (algorithm 1).

The most critical step in this procedure is to identify and curette the internal opening to reduce the risk of recurrence. A probe is inserted into the internal opening and gently passed along the fistula tract to the external opening (figure 8). An incision is made over the entire length of the fistula using the probe as a guide (picture 3). The tract is gently curetted, and an absorbable stitch is used to marsupialize the tract to promote healing. We prefer to marsupialize the tract as it may speed up wound healing [20]. The wound is gently packed with a petroleum-based gauze and covered with a sterile dressing [21]. Topical ointments, such as 10% sucralfate or 2% phenytoin, may decrease postoperative pain and improved healing when applied to the fistulotomy site [22,23].

PROCEDURES FOR COMPLEX FISTULAS — The following procedures are used to treat complex fistulas. The common technical component of all operative procedures is the identification and curetting of the internal opening to ensure adequate drainage [10].

Cutting seton — A cutting seton is a reactive suture or elastic that is placed through the fistula tract and tightened at regular intervals. It slowly cuts through the tract, causing scarring, thus preventing the wide disruption of the anal sphincter associated with fistulotomy. A cutting seton may be used in the management of complex cryptoglandular anal fistulas, but patient selection is critical to avoiding functional impairment [8].

The internal opening is identified, and a probe inserted between the internal and external openings as previously described. The skin bridge is opened completely between the internal and external openings, and a small piece of braided silk or an elastic vessel loop is pulled through the fistulous tract. This seton is secured snugly around the sphincter muscle (figure 9). For a cutting seton to work properly, the skin bridge and subcutaneous tissue between the seton and muscle must be completely divided (picture 4).

Patients are examined at monthly intervals, and the seton is tightened until the deep space is obliterated. The seton promotes granulation tissue formation and allows the edges of the wound to become firm before the sphincter is divided. The seton will slowly divide the fistulous tissue tract on the leading edge of the seton while allowing healing to occur on the trailing edge and preserving sphincter continuity and theoretically preserving sphincter function. Incontinence occurs not because the sphincter muscle is divided but when the muscle fibers retract and the space in between is filled with scar tissue.

There is wide variation in the amount of time that cutting setons remain in situ. Shortened periods between seton tightening may result in poor outcomes. From basic biology principles, significant collagen deposition and fibrosis occur over a period of four to six weeks, so setons that cut through more rapidly than this may not provide adequate time for scarring to occur [24].

Advancement flaps — The endoanal and endorectal advancement flaps preserve the anal sphincter by closing off the internal opening of the fistula by a mobilized flap of healthy tissue consisting of mucosa and submucosa, with or without the internal sphincter [25]. The flap provides tissue coverage of tract internal opening and allows the tract to heal and close (figure 10).

Endoanal and endorectal advancement flaps are the preferred approach for complicated anorectal fistulas without coexisting incontinence [26]. Not all anorectal fistula patients are candidates for mucosal flap advancement. As examples, very high fistulas, posterior fistulas in men with deep buttocks, or fistulas with internal opening distal to the dentate line are technically challenging to treat by this technique [8]. Additionally, anal stenosis, active proctitis, and inflammatory bowel disease are relative contraindications due to high complication and failure rates [27-29].

The key component of this procedure is to create a flap that includes the mucosa, submucosa, and a portion of the circular muscular fibers that is sufficient to cover the internal opening. The base of the flap proximally should measure at least twice its width at the apex. The flap is raised by making a curvilinear incision around the dentate line. The incision should not extend more than one-third of the anal canal circumference to prevent stricture formation. If dilute epinephrine is used to control bleeding, care should be taken not to raise a flap that is too thin. A thin flap may result in ischemia and may not provide sufficient integrity to adequately cover the internal opening and prevent recurrence.

After the fistulous tract is curetted and debrided, the flap is advanced and sutured in place. We prefer to anchor the center and most cephalad portion of the underside of the flap first; then, the lateral portion of the flap is secured with a running or interrupted suture.

Ligation of the intersphincteric fistula tract — Ligation of the intersphincteric fistula tract (LIFT) is a sphincter-sparing procedure for complex transsphincteric fistulas first described in 2009 (figure 11 and picture 5). This approach is performed through the intersphincteric plane. The procedure is based on the secure closure of the internal opening and removal of infected cryptoglandular tissue [14,30,31].

The intersphincteric tract is identified and isolated by meticulous dissection. Once isolated, the intersphincteric tract is hooked using a small, right-angled clamp. The tract is ligated close to the internal sphincter and then divided distal to the point of ligation.

Hydrogen peroxide is injected through the external opening to confirm the division of the correct tract. The external opening and the remnant fistulous tract are curetted to the level close to the external sphincter complex. Finally, the intersphincteric incision is loosely reapproximated with an absorbable suture. The curettaged wound is left opened for dressing [14].

A modification to the LIFT technique unroofs the fistula from the internal opening, therefore eliminating the intersphincteric wound. In one study, outcomes of the modified LIFT were comparable to those of the original LIFT with shorter operative time [32].

Modified Hanley procedure — The modified Hanley procedure is a sphincter-preserving procedure for the treatment of horseshoe abscesses and fistulas (picture 4) [33]. (See "Perianal and perirectal abscess", section on 'Horseshoe'.)

The modified Hanley procedure is performed in difficult cases of anorectal fistulas, including patients with:

Horseshoe fistulas

Ischiorectal fistulas

Deep postanal abscesses with fistulas

Recurrent fistulas

The key components of this technique are to identify and drain all fistulous tracts. A probe is inserted through the internal opening into the deep space abscess cavity. An incision is made in the posterior midline, initially avoiding the superficial external sphincter. The midline incision is then deepened parallel to and through the fibers of the superficial external sphincter, thereby unroofing the deep space for drainage. A probe is then guided through the internal opening to exit through the midline surgical incision. The walls of the deep space are inspected to identify limbs of the horseshoe abscess fistula.

If a deep postanal abscess or extension into the ischiorectal fossa is identified, we prefer to use a modified Hanley technique for definitive management with draining lateral setons and a cutting seton in the posterior midline.

A counterincision is made over the appropriate site with the subsequent incision, drainage, and curettage of all of the fistulous tracts. Next, the seton is attached to the midline probe and retrieved through the internal opening and secured to itself with a 0-silk suture. The underlying perianal skin and anoderm between the primary midline opening and the secondary midline surgical incision are removed to allow subsequent tightening of the seton. A Penrose drain is placed in the tract between the posterior midline opening and any lateral opening(s) and removed 24 to 48 hours after surgery [34]. The posterior midline opening can be managed by an endoanal flap or a cutting seton (ie, modified Hanley procedure).

Fibrin sealant — Fibrin sealant is a minimally invasive treatment option for anal fistulas. A mixture of fibrinogen, thrombin, and calcium ions forms a clot that is injected into the fistula tract, and within 10 to 60 seconds the fistula is potentially sealed [35,36]. This approach avoids sphincter division, but long-term results have not been encouraging (picture 6).

A catheter is typically inserted through the external opening and advanced to the internal opening. At the internal opening, a seal is created with fibrin, and then 2 to 5 mL of fibrin sealant is injected as the catheter is withdrawn. At the external opening, another plug is created, resulting in a dumbbell-shaped seal.

Fistula plug — The biosynthetic fistula plug is made of lyophilized porcine small intestinal mucosa. It does not generate a foreign body reaction or necessitate disruption of the anal sphincter, and it eliminates the risk of sphincter dysfunction associated with other procedures, such as fistulotomy and setons [10,37]. The fistula plug was designed to ameliorate postoperative incontinence in high-risk fistula patients, such as fistulas with high internal openings, anterior fistulas, or those that transverse significant portions of sphincter muscle (picture 7).

Once the anatomy of the fistula is confirmed, the fistula plug is prepared by immersion into isotonic saline. A 2-0 silk suture is introduced into the internal opening and pulled through the entire length of the fistula tract with the assistance of the previously placed silastic seton or a lacrimal probe. With the suture coursing through the fistula tract, the tapered end of the fistula plug is attached, and the plug is pulled into the fistula from the internal opening toward the external opening until snug.

Excess fistula plug material is trimmed from both ends. The fistula tract length is determined by subtracting the length of trimmed excess plug material from the original plug length. The fistula plug is fixed and buried within the internal sphincter at the internal opening by a large figure-of-eight stitch with an absorbable suture. Care is taken to avoid occluding the external opening of the tract, thereby preserving a route for external drainage.

Minimally invasive techniques — Newer minimally invasive approaches to treat fistula-in-ano that use endoscopic or laser closure techniques have reasonable short-term healing rates but unknown long-term fistula healing and recurrence rates [8]. These include:

Video-assisted anal fistula treatment involves fistuloscopy through the external opening to identify the internal opening, closure of the internal orifice with sutures, clips, or a stapling device, and selective debridement or obliteration of the fistula tract [38].

Laser fistula closure uses a radially emitting laser probe that, when passed along the tract, traumatizes the epithelium and obliterates the fistula tract [39].

Endoscopic clipping, which is frequently combined with a fistuloscopy, places a superelastic nitinol clip over the internal fistula opening with the aid of a transanal applicator [40].

Diversion — In our practice, we rarely create a diverting stoma to facilitate the treatment of cryptoglandular anorectal fistula disease. Select patients with severe anorectal Crohn disease, reoperative rectovaginal fistulas, extrasphincteric fistulas, perineal necrotizing fasciitis, and radiation-induced fistulas may require diversion to heal a persistent fistula. Fecal diversion alone is effective in these select patients, but long-term success following reanastomosis is low because of recurrence from the underlying disease [41]. There are no parameters to identify those in whom a successful outcome is likely.

POSTOPERATIVE MANAGEMENT — Patients are routinely discharged home the same day as the procedure. Pain is managed by nonsteroidal anti-inflammatory medications or opioids, depending on the extent of the procedure.

Our general postoperative instructions are as follows:

Activity

Activity as tolerated.

No lifting over 20 pounds for two weeks.

No strenuous exercise, running, or aerobics for two weeks.

No driving for 48 hours post-surgery and none while taking narcotics.

Do not use a doughnut-shaped pillow.

Diet

Consume a high-fiber diet.

Add a dietary fiber supplement two to three times a day in juice, coffee, or a noncarbonated beverage.

Drink two liters of water or an electrolyte-balanced drink daily.

Hygiene

Soak the anal opening in a sitz bath of warm water for 15 minutes three times a day and after each bowel movement.

Use moist cotton pads or moist towelettes rather than toilet tissue.

Place a cotton ball between buttocks at the anal opening.

Bowel management

Take two tablespoons of mineral oil for the first five nights; discontinue for loose stools.

If no bowel movement for 72 hours, or if severe straining occurs, take one tablespoon of milk of magnesia every four to six hours until relief.

If constipation continues for 48 hours after beginning milk of magnesia, then consume 10 ounces of magnesium citrate.

Slight bleeding with bowel movements is expected. Contact office for excessive amounts (one-half cup) of blood.

Follow-up — Office-based anoscopy is performed at three and six months following the procedure. Failure of the procedure is defined as patient complaints of persistent drainage, anoscopic identification of persistent abscess or external fistula opening, or development of abscess or infection requiring additional surgery. The risk of these complications is described above with the discussion of specific procedures.

OUTCOMES — Patients should be observed for a minimum of six months following a definitive procedure before determining a treatment failure or success [42]. The most concerning potential complication of a fistulotomy is incontinence from procedure-related damage to the external anal sphincter. The divided muscle fibers retract, and the result is solid fecal, liquid fecal, or gas incontinence.

In a retrospective review of 9536 fistulas treated in Italy over 15 years (5520 simple and 4016 complex), the overall healing rate of simple fistulas was 81.1 percent (91.9 percent sphincter-cutting versus 65.1 percent sphincter-sparing) [43]. Fistulotomy was the most frequently used procedure, although its popularity waned over the years, with a concomitant increase in the use of sphincter-sparing approaches. The overall healing rate of complex fistulas was 69.0 percent (81.1 percent sphincter-cutting versus 61.4 percent sphincter-sparing).

Fistulotomy – Primary fistulotomy is associated with a healing rate of >90 percent [19,44]. When fistulotomy is used for simple anal fistulas in properly selected patients, the risk of fecal incontinence is minimal or none [18,19]. The incontinence rate of fistulotomy for high-lying or complex fistulas are higher, ranging from 10 to 40 percent [45-48]. Recurrence rates for an anorectal fistula treated with a fistulotomy are generally reported to be low [21,24,49-54]. In an observational study with median 76 months follow-up, the three-year recurrence rate for 109 patients with a low-lying simple fistula treated was 7 percent [54]. (See 'Fistulotomy for simple fistulas' above.)

Cutting seton – A 2009 review of 37 studies on cutting seton reported fecal incontinence rates ranging from 0 to 67 percent, with the rate increasing as the location of the internal opening of the fistula moved more proximally [55]. More contemporary studies reported a high success rate of 98 percent, and an incontinence rate of 12 to 22 percent, but only 7 percent were new-onset after surgery [56,57]. (See 'Cutting seton' above.)

Advancement flap – A variety of endoanal advancement flap techniques exist and, in experienced hands, have relatively high healing rate (66 to 87 percent), low-to-moderate recurrence rates (0 to 40 percent), depending in part on patient population, and tolerable incontinence rates ranging from 0 to 12.5 percent [25,28,54,58-64]. The wide range in outcomes is due to heterogeneity in patient populations, technique, and experience. (See 'Advancement flaps' above.)

Ligation of intersphincteric fistulous tract (LIFT) – Outcomes data vary depending on the type of fistulas [14,18,30,65-67]. Meta-analyses report that the standard LIFT procedure achieved fistula healing in 61 to 94 percent of patients in four to eight weeks, with low morbidity (14 percent) and rare fecal incontinence (1.4 percent) [68-70]. Various modifications to the standard LIFT procedure do not appear to affect its performance [71,72]. Horseshoe fistula, Crohn disease, and previous fistula surgery predict failure of the LIFT procedure [70]. (See 'Ligation of the intersphincteric fistula tract' above.)

Modified Hanley procedure – In a retrospective review of 23 patients with high transsphincteric horseshoe fistulas treated by a modified Hanley procedure using cutting setons, 91 percent had complete healing within eight months, and no incontinence was reported [33]. This procedure requires months of postoperative care but is safe and effective. (See 'Modified Hanley procedure' above.)

Fibrin sealant – Fibrin sealant injections are occasionally used to treat complex fistulas. The main benefit is sphincter preservation. But overall, it is not very effective, with a primary healing rate of only 18 to 41 percent [73,74]. The recurrence rate for fistulas repaired with fibrin glue alone ranges from 14 to 69 percent, depending on the complexity of the fistula, duration of observation, and technical aspects, such as debridement of the fistulous openings [16,17,75]. Fibrin glue extravasation from within the fistula tract and failure to identify and completely fill all branches of the tract with glue are the likely explanations for long-term failure. (See 'Fibrin sealant' above.)

Fistula plug – Initial reports of the fistula plug were favorable, particularly in high-risk fistula patients in whom treatment with fistulotomy, cutting setons, or mucosal advancement flaps was ineffective or caused unacceptably high incontinence rates [76,77]. However, the use of fistula plugs, especially in high or complex fistulas, has waned due to reported low healing rates of <50 percent [78-81]. A 2016 systematic review identified six studies, which reported healing rates between 15.8 and 72.7 percent at a follow-up ranging between 2 and 19 months [82]. Another systematic review reported early plug failure rate of 4 to 41 percent, usually due to localized sepsis or plug dislodgement [83]. (See 'Fistula plug' above.)

Minimally invasive techniques – In a 2017 systematic review of 18 studies involving the three minimally invasive technique discussed above with follow-up ranging from 6 to 69 months, the short-term (<1 year) healing rate was 64 to 100 percent [84]. Morbidity was low and the incontinence risk was negligible. (See 'Minimally invasive techniques' above.)

In a meta-analysis of three randomized trials [63,85] comparing LIFT with advancement flap, the two procedures had similar odds of healing, recurrence, and complications; LIFT was associated with less pain and lower risk of fecal incontinence [86].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Anal abscess and anal fistula".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

Basics topics (see "Patient education: Anal abscess and fistula (The Basics)")

SUMMARY AND RECOMMENDATIONS

Overview – Anorectal fistulas are a heterogeneous group of disorders that can cause significant pain, social impairment, hygienic disdain, and, rarely, sepsis. Surgery is the mainstay of treatment for cryptoglandular fistulas unrelated to Crohn disease, other infectious processes, or malignancy, yet no one procedure is universally efficacious and safe. (See 'Introduction' above.)

Examination under anesthesia and seton placement – Patients with a suspected anorectal fistula should undergo an examination under anesthesia to confirm the diagnosis of a fistula and place a seton to secure and drain the fistulous tract. (See 'Examination under anesthesia and seton placement' above.)

Simple fistula with normal continence – For patients with no existing incontinence or risk factors for future incontinence and a well-drained, low-lying (<30 percent of sphincter complex) transsphincteric or an intersphincteric simple fistula, we suggest a primary fistulotomy rather than a sphincter-sparing procedure (Grade 2C). However, fistulotomy is contraindicated in patients with preexisting incontinence. (See 'Fistulotomy for simple fistulas' above.)

Complex fistula or incontinence – For patients with existing incontinence or concerns for future incontinence and/or patients with a complex fistula, we suggest performing a sphincter-sparing procedure six or more weeks after placement of the draining seton (Grade 2C). The choice of the procedure is dictated by fistula anatomy and surgeon preference (algorithm 1):

For patients with a high transsphincteric fistula (≥30 percent of sphincter complex) and patients with preexisting incontinence, we perform LIFT for fistulas with an internal opening distal to the dentate line. When the primary opening is at the dentate line, either an advancement flap or LIFT can be performed. (See 'Advancement flaps' above and 'Ligation of the intersphincteric fistula tract' above.)

For patients with a suprasphincteric fistula, we perform an advancement flap. Such fistulas have no intersphincteric tract and therefore cannot be treated with LIFT. (See 'Advancement flaps' above.)

Extrasphincteric fistulas are typically not of cryptoglandular origin but instead caused by cancer or Crohn disease. These fistulas are rare but difficult to treat. Surgical options include proctectomy or fecal diversion. (See 'Diversion' above.)

For patients with a horseshoe fistula, we perform either the modified Hanley procedure, which involves a posterior midline incision and unroofing of all fistulous tracts, or an advancement flap. (See 'Modified Hanley procedure' above.)

Patients with a recurrent fistula require a pelvic MRI scan to clarify anatomy and a seton for drainage. Further surgical treatment is dictated by fistula anatomy as outlined above. Options include modified Hanley procedure, cutting seton, and advancement flap. (See 'Recurrent fistula' above.)

Outcomes – The reported healing rate of simple and complex fistulas are 81 and 69 percent, respectively. Incontinence, complication, and recurrence rate differs between procedures. (See 'Outcomes' above.)

  1. Williams JG, Farrands PA, Williams AB, et al. The treatment of anal fistula: ACPGBI position statement. Colorectal Dis 2007; 9 Suppl 4:18.
  2. Gurer A, Ozlem N, Gokakin AK, et al. A novel material in seton treatment of fistula-in-ano. Am J Surg 2007; 193:794.
  3. Hollinshead WH. The perineum. In: Textbook of Anatomy, Hollinshead WH (Ed), Harper and Row, Hagerstown, Maryland 1974.
  4. Boileau Grant JC. Perineum and pelvis. In: An Atlas of Anatomy, The Williams and Wilkins Co., Baltimore 1972.
  5. Large Intestine. In: Gray's Anatomy: The Anatomical Basis of Clinical Practice, 40th ed, Standring S (Ed), Elsevier, 2008. p.1137.
  6. Rociu E, Stoker J, Eijkemans MJ, Laméris JS. Normal anal sphincter anatomy and age- and sex-related variations at high-spatial-resolution endoanal MR imaging. Radiology 2000; 217:395.
  7. Zbar AP. David Henry Goodsall: reassessment of the rule. Tech Coloproctol 2009; 13:185.
  8. Gaertner WB, Burgess PL, Davids JS, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum 2022; 65:964.
  9. Shaw D, Ternent CA. Perioperative Management of the Ambulatory Anorectal Surgery Patient. Clin Colon Rectal Surg 2016; 29:7.
  10. Rizzo JA, Naig AL, Johnson EK. Anorectal abscess and fistula-in-ano: evidence-based management. Surg Clin North Am 2010; 90:45.
  11. Durgun V, Perek A, Kapan M, et al. Partial fistulotomy and modified cutting seton procedure in the treatment of high extrasphincteric perianal fistulae. Dig Surg 2002; 19:56.
  12. Bolshinsky V, Church J. How to Insert a Draining Seton Correctly. Dis Colon Rectum 2018; 61:1121.
  13. Holzheimer RG, Siebeck M. Treatment procedures for anal fistulous cryptoglandular abscess--how to get the best results. Eur J Med Res 2006; 11:501.
  14. Shanwani A, Nor AM, Amri N. Ligation of the intersphincteric fistula tract (LIFT): a sphincter-saving technique for fistula-in-ano. Dis Colon Rectum 2010; 53:39.
  15. Cavanaugh M, Hyman N, Osler T. Fecal incontinence severity index after fistulotomy: a predictor of quality of life. Dis Colon Rectum 2002; 45:349.
  16. van Koperen PJ, Wind J, Bemelman WA, Slors JF. Fibrin glue and transanal rectal advancement flap for high transsphincteric perianal fistulas; is there any advantage? Int J Colorectal Dis 2008; 23:697.
  17. Loungnarath R, Dietz DW, Mutch MG, et al. Fibrin glue treatment of complex anal fistulas has low success rate. Dis Colon Rectum 2004; 47:432.
  18. Hall JF, Bordeianou L, Hyman N, et al. Outcomes after operations for anal fistula: results of a prospective, multicenter, regional study. Dis Colon Rectum 2014; 57:1304.
  19. Abramowitz L, Soudan D, Souffran M, et al. The outcome of fistulotomy for anal fistula at 1 year: a prospective multicentre French study. Colorectal Dis 2016; 18:279.
  20. Anan M, Emile SH, Elgendy H, et al. Fistulotomy with or without marsupialisation of wound edges in treatment of simple anal fistula: a randomised controlled trial. Ann R Coll Surg Engl 2019; 101:472.
  21. Zollinger RM, Zollinger Jr RM. Plate CXCVII: Drainage of ischiorectal abscess - Excision of fistula in ano. In: Atlas of Surgical Operations, 5th ed, Zollinger RM, Zollinger Jr RM (Eds), MacMilliam Publishing Company, New York 1983. p.418.
  22. Alvandipour M, Ala S, Tavakoli H, et al. Efficacy of 10% sucralfate ointment after anal fistulotomy: A prospective, double-blind, randomized, placebo-controlled trial. Int J Surg 2016; 36:13.
  23. Sanad A, Emile S, Thabet W, Ellaithy R. A randomized controlled trial on the effect of topical phenytoin 2% on wound healing after anal fistulotomy. Colorectal Dis 2019; 21:697.
  24. Byrne C, Solomon M. The use of setons in fistula-in-ano. Semin Colon Rectal Surg 2009; 20:10.
  25. Soltani A, Kaiser AM. Endorectal advancement flap for cryptoglandular or Crohn's fistula-in-ano. Dis Colon Rectum 2010; 53:486.
  26. Bastawrous A, Cintron J. Anorectal abscess and fistula. In: Current Surgical Therapy, 8th ed, Cameron J (Ed), Elsevier Mosby, Philadelphia 2004. p.256.
  27. Ozuner G, Hull TL, Cartmill J, Fazio VW. Long-term analysis of the use of transanal rectal advancement flaps for complicated anorectal/vaginal fistulas. Dis Colon Rectum 1996; 39:10.
  28. Mizrahi N, Wexner SD, Zmora O, et al. Endorectal advancement flap: are there predictors of failure? Dis Colon Rectum 2002; 45:1616.
  29. Boenicke L, Karsten E, Zirngibl H, Ambe P. Advancement Flap for Treatment of Complex Cryptoglandular Anal Fistula: Prediction of Therapy Success or Failure Using Anamnestic and Clinical Parameters. World J Surg 2017; 41:2395.
  30. Bleier JI, Moloo H, Goldberg SM. Ligation of the intersphincteric fistula tract: an effective new technique for complex fistulas. Dis Colon Rectum 2010; 53:43.
  31. Rojanasakul A. LIFT procedure: a simplified technique for fistula-in-ano. Tech Coloproctol 2009; 13:237.
  32. Bastawrous A, Hawkins M, Kratz R, et al. Results from a novel modification to the ligation intersphincteric fistula tract. Am J Surg 2015; 209:793.
  33. Browder LK, Sweet S, Kaiser AM. Modified Hanley procedure for management of complex horseshoe fistulae. Tech Coloproctol 2009; 13:301.
  34. Ustynoski K, Rosen L, Stasik J, et al. Horseshoe abscess fistula. Seton treatment. Dis Colon Rectum 1990; 33:602.
  35. Spotnitz WD. Fibrin sealant: past, present, and future: a brief review. World J Surg 2010; 34:632.
  36. Saxena S, Jain P, Shukla J . Preparation of two component fibrin glue and its clinical evaluation in skin grafts and flaps. Indian J Plast Surg 2003; 36:14.
  37. Ellis CN. Bioprosthetic plugs for complex anal fistulas: an early experience. J Surg Educ 2007; 64:36.
  38. Seow-En I, Seow-Choen F, Koh PK. An experience with video-assisted anal fistula treatment (VAAFT) with new insights into the treatment of anal fistulae. Tech Coloproctol 2016; 20:389.
  39. Elfeki H, Shalaby M, Emile SH, et al. A systematic review and meta-analysis of the safety and efficacy of fistula laser closure. Tech Coloproctol 2020; 24:265.
  40. Prosst RL, Joos AK. Short-term outcomes of a novel endoscopic clipping device for closure of the internal opening in 100 anorectal fistulas. Tech Coloproctol 2016; 20:753.
  41. Yamamoto T, Allan RN, Keighley MR. Effect of fecal diversion alone on perianal Crohn's disease. World J Surg 2000; 24:1258.
  42. Cintron JR, Park JJ, Orsay CP, et al. Repair of fistulas-in-ano using fibrin adhesive: long-term follow-up. Dis Colon Rectum 2000; 43:944.
  43. Litta F, Bracchitta S, Naldini G, et al. FISSIT (Fistula Surgery in Italy) study: A retrospective survey on the surgical management of anal fistulas in Italy over the last 15 years. Surgery 2021; 170:689.
  44. Litta F, Parello A, De Simone V, et al. Fistulotomy and primary sphincteroplasty for anal fistula: long-term data on continence and patient satisfaction. Tech Coloproctol 2019; 23:993.
  45. Göttgens KW, Janssen PT, Heemskerk J, et al. Long-term outcome of low perianal fistulas treated by fistulotomy: a multicenter study. Int J Colorectal Dis 2015; 30:213.
  46. Bokhari S, Lindsey I. Incontinence following sphincter division for treatment of anal fistula. Colorectal Dis 2010; 12:e135.
  47. van Tets WF, Kuijpers HC. Continence disorders after anal fistulotomy. Dis Colon Rectum 1994; 37:1194.
  48. Jordán J, Roig JV, García-Armengol J, et al. Risk factors for recurrence and incontinence after anal fistula surgery. Colorectal Dis 2010; 12:254.
  49. Ho YH, Tan M, Chui CH, et al. Randomized controlled trial of primary fistulotomy with drainage alone for perianal abscesses. Dis Colon Rectum 1997; 40:1435.
  50. Christensen A, Nilas L, Christiansen J. Treatment of transsphincteric anal fistulas by the seton technique. Dis Colon Rectum 1986; 29:454.
  51. Hammond TM, Knowles CH, Porrett T, Lunniss PJ. The Snug Seton: short and medium term results of slow fistulotomy for idiopathic anal fistulae. Colorectal Dis 2006; 8:328.
  52. Cox SW, Senagore AJ, Luchtefeld MA, Mazier WP. Outcome after incision and drainage with fistulotomy for ischiorectal abscess. Am Surg 1997; 63:686.
  53. Vaizey CJ, Carapeti E, Cahill JA, Kamm MA. Prospective comparison of faecal incontinence grading systems. Gut 1999; 44:77.
  54. van Koperen PJ, Wind J, Bemelman WA, et al. Long-term functional outcome and risk factors for recurrence after surgical treatment for low and high perianal fistulas of cryptoglandular origin. Dis Colon Rectum 2008; 51:1475.
  55. Ritchie RD, Sackier JM, Hodde JP. Incontinence rates after cutting seton treatment for anal fistula. Colorectal Dis 2009; 11:564.
  56. Patton V, Chen CM, Lubowski D. Long-term results of the cutting seton for high anal fistula. ANZ J Surg 2015; 85:720.
  57. Rosen DR, Kaiser AM. Definitive seton management for transsphincteric fistula-in-ano: harm or charm? Colorectal Dis 2016; 18:488.
  58. Lewis P, Bartolo DC. Treatment of trans-sphincteric fistulae by full thickness anorectal advancement flaps. Br J Surg 1990; 77:1187.
  59. Sonoda T, Hull T, Piedmonte MR, Fazio VW. Outcomes of primary repair of anorectal and rectovaginal fistulas using the endorectal advancement flap. Dis Colon Rectum 2002; 45:1622.
  60. Miller GV, Finan PJ. Flap advancement and core fistulectomy for complex rectal fistula. Br J Surg 1998; 85:108.
  61. van Onkelen RS, Gosselink MP, Thijsse S, Schouten WR. Predictors of outcome after transanal advancement flap repair for high transsphincteric fistulas. Dis Colon Rectum 2014; 57:1007.
  62. Jarrar A, Church J. Advancement flap repair: a good option for complex anorectal fistulas. Dis Colon Rectum 2011; 54:1537.
  63. Madbouly KM, El Shazly W, Abbas KS, Hussein AM. Ligation of intersphincteric fistula tract versus mucosal advancement flap in patients with high transsphincteric fistula-in-ano: a prospective randomized trial. Dis Colon Rectum 2014; 57:1202.
  64. Mitalas LE, Dwarkasing RS, Verhaaren R, et al. Is the outcome of transanal advancement flap repair affected by the complexity of high transsphincteric fistulas? Dis Colon Rectum 2011; 54:857.
  65. Tan KK, Tan IJ, Lim FS, et al. The anatomy of failures following the ligation of intersphincteric tract technique for anal fistula: a review of 93 patients over 4 years. Dis Colon Rectum 2011; 54:1368.
  66. Liu WY, Aboulian A, Kaji AH, Kumar RR. Long-term results of ligation of intersphincteric fistula tract (LIFT) for fistula-in-ano. Dis Colon Rectum 2013; 56:343.
  67. Gingold DS, Murrell ZA, Fleshner PR. A prospective evaluation of the ligation of the intersphincteric tract procedure for complex anal fistula in patients with Crohn's disease. Ann Surg 2014; 260:1057.
  68. Hong KD, Kang S, Kalaskar S, Wexner SD. Ligation of intersphincteric fistula tract (LIFT) to treat anal fistula: systematic review and meta-analysis. Tech Coloproctol 2014; 18:685.
  69. Zirak-Schmidt S, Perdawood SK. Management of anal fistula by ligation of the intersphincteric fistula tract - a systematic review. Dan Med J 2014; 61:A4977.
  70. Emile SH, Khan SM, Adejumo A, Koroye O. Ligation of intersphincteric fistula tract (LIFT) in treatment of anal fistula: An updated systematic review, meta-analysis, and meta-regression of the predictors of failure. Surgery 2020; 167:484.
  71. Sirany AM, Nygaard RM, Morken JJ. The ligation of the intersphincteric fistula tract procedure for anal fistula: a mixed bag of results. Dis Colon Rectum 2015; 58:604.
  72. Han JG, Wang ZJ, Zheng Y, et al. Ligation of Intersphincteric Fistula Tract vs Ligation of the Intersphincteric Fistula Tract Plus a Bioprosthetic Anal Fistula Plug Procedure in Patients With Transsphincteric Anal Fistula: Early Results of a Multicenter Prospective Randomized Trial. Ann Surg 2016; 264:917.
  73. de la Portilla F, Muñoz-Cruzado MVD, Maestre MV, et al. Platelet-rich plasma (PRP) versus fibrin glue in cryptogenic fistula-in-ano: a phase III single-center, randomized, double-blind trial. Int J Colorectal Dis 2019; 34:1113.
  74. Sugrue J, Mantilla N, Abcarian A, et al. Sphincter-Sparing Anal Fistula Repair: Are We Getting Better? Dis Colon Rectum 2017; 60:1071.
  75. de la Portilla F, Rada R, León E, et al. Evaluation of the use of BioGlue in the treatment of high anal fistulas: preliminary results of a pilot study. Dis Colon Rectum 2007; 50:218.
  76. Johnson EK, Gaw JU, Armstrong DN. Efficacy of anal fistula plug vs. fibrin glue in closure of anorectal fistulas. Dis Colon Rectum 2006; 49:371.
  77. Champagne BJ, O'Connor LM, Ferguson M, et al. Efficacy of anal fistula plug in closure of cryptoglandular fistulas: long-term follow-up. Dis Colon Rectum 2006; 49:1817.
  78. Stamos MJ, Snyder M, Robb BW, et al. Prospective multicenter study of a synthetic bioabsorbable anal fistula plug to treat cryptoglandular transsphincteric anal fistulas. Dis Colon Rectum 2015; 58:344.
  79. Safar B, Jobanputra S, Sands D, et al. Anal fistula plug: initial experience and outcomes. Dis Colon Rectum 2009; 52:248.
  80. Christoforidis D, Pieh MC, Madoff RD, Mellgren AF. Treatment of transsphincteric anal fistulas by endorectal advancement flap or collagen fistula plug: a comparative study. Dis Colon Rectum 2009; 52:18.
  81. Tan KK, Kaur G, Byrne CM, et al. Long-term outcome of the anal fistula plug for anal fistula of cryptoglandular origin. Colorectal Dis 2013; 15:1510.
  82. Narang SK, Jones C, Alam NN, et al. Delayed absorbable synthetic plug (GORE® BIO-A®) for the treatment of fistula-in-ano: a systematic review. Colorectal Dis 2016; 18:37.
  83. Kontovounisios C, Tekkis P, Tan E, et al. Adoption and success rates of perineal procedures for fistula-in-ano: a systematic review. Colorectal Dis 2016; 18:441.
  84. Adegbola SO, Sahnan K, Pellino G, et al. Short-term efficacy and safety of three novel sphincter-sparing techniques for anal fistulae: a systematic review. Tech Coloproctol 2017; 21:775.
  85. Mushaya C, Bartlett L, Schulze B, Ho YH. Ligation of intersphincteric fistula tract compared with advancement flap for complex anorectal fistulas requiring initial seton drainage. Am J Surg 2012; 204:283.
  86. Emile SH, Garoufalia Z, Aeschbacher P, et al. Endorectal advancement flap compared to ligation of inter-sphincteric fistula tract in the treatment of complex anal fistulas: A meta-analysis of randomized clinical trials. Surgery 2023; 174:172.
Topic 13508 Version 28.0

References

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