Anal Fistula Plug

Bruce W. Robb

Marc A. Singer

Indications/Contraindications

Treatment of anal fistula can be a frustrating problem for both the patient and the surgeon. While simple fistulas are generally very effectively treated with fistulotomy, the treatment of complex fistula has proven more difficult. Fistulotomy or cutting seton is an effective treatment for fistula closure, but may cause fecal incontinence. The search for effective treatments that do not compromise continence has led to the use of fibrin glue, the ligation of the intersphincteric fistula tract (LIFT), endorectal advancement flaps, and the use of absorbable materials as anal fistula plugs. Initial use of anal fistula plugs was conceived and described by Brad Sklow. Inspired by a case report by Schultz and coworkers in the Journal of the American College of Surgeons, which described the use of a tightly rolled sheet of porcine small intestine submucosa placed in an enterocutaneous fistula tract as a plug. This technique was modified for anal fistula. Subsequently, a specially designed plug was fashioned by Cook Medical Inc. (Surgisis® Anal Fistula Plug™). Conceptually simple, anal fistula plugs provide a matrix upon which tissue growth may occur leading to fistula closure with no theoretical risk to continence.

Contraindications

Persistent abscess or infection
Intersphincteric fistula (when no contraindication to fistulotomy exists)
Inability to identify the internal and external openings
Allergy to plug material

Currently, there are two commercially available fistula plugs approved by the FDA: Cook Surgisis® AFP™ Anal Fistula Plug (Cook Surgical Inc., Bloomington, IN) and the Gore® Bio-A® Fistula Plug (a new product from W. L. Gore Corporation, Newark, DE). They vary in both design and material from which they are constructed.

Preoperative Planning

Patients should have undergone previous surgical drainage of the perirectal abscess and have had a draining seton placed 6–12 weeks in advance of fistula plug placement. A plug may be placed primarily only in those patients who have no evidence of infection and a well-formed fistula tract. A single dose of a broad-spectrum preoperative antibiotic is recommended. No consensus about bowel preparation exists, with some authors advocating complete mechanical preparations and others simply administering an enema on the morning of the procedure. It should be stressed that there should be no active infection present at the time of surgery and the patients have a well-formed tract.

Surgery

The anal fistula plug has been widely adopted for complex anal fistula surgery because of its favorable safety profile with regards to continence and purported technical ease. There have been wide variations in published outcomes with those authors who are most successful attributing the differences to patient selection and technical details. In 2007, a group of surgeons experienced in the use of the Surgisis® Anal Fistula Plug™ met and issued a set of recommendations for its most effective use.

Positioning

Patient positioning and anesthesia can be performed according to the surgeon’s preference for anorectal procedures. Positioning is generally easily accomplished with patients sedated in the prone jack-knife position with either a pudendal nerve block or a spinal anesthetic. However, many published series employ general anesthesia and the lithotomy position.

Technique

The previously placed draining seton is noted (Fig. 7.1). The perineum and anal canal are again inspected to confirm that all internal and external openings have been identified. A thorough inspection should also verify that there is no active infection prior to preparing the fistula plug. A 2-0 suture is secured to the seton. The seton is then cut and pulled out of the fistula so that the suture now crosses the fistula leaving the needle on the “internal opening” side of the fistula (Fig. 7.2). The fistula tract is then irrigated with dilute hydrogen peroxide using an angiocatheter or gently debrided with a cytobrush or small curettes (Figs. 7.3 and 7.4). Finally, the tract is irrigated with saline. The plugs require rehydration fully submerged in sterile saline for no more than 2 minutes. Placement of a surgical instrument such a hemostat over the plug in a bowel of saline will keep the material submerged. The previously placed suture is secured to the plug material on the “external opening” side of the plug. The suture is then used to draw the plug material through the fistula tract. The plug is then secured at the internal opening. The plug is secured with an absorbable suture such as a 2-0 coated polyglycolic acid, anchoring it to the sphincter complex and covering the plug. Two sutures placed at right angles to one another are recommended. These sutures are placed through the sphincter muscle and then separately through the plug so as to “bury” the plug. If necessary, the plug is trimmed at this time. Some surgeons choose to create small mucosal flaps to better cover the plug at the internal opening. The Gore® Bio-A® Fistula Plug is designed to be sized to the fistula tract with removable limbs attached to a central disk. Placement is similar to that of the Surgisis® Anal Fistula Plug™ in that the seton is used to bring a suture through the tract, which is then secured to the “sized” plug that has been previously wetted. The suture should be placed approximately 3 mm from the ends of the plug so as to have enough strength to pull the plug into the tract but not to fold over too much and make it difficult to pull into the tract (Figs. 7.5

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