A fistula is a tunnel which abnormally connects one part of the body or organ to another. Within the context of anal and rectal surgery, anal fistulas typically connect the anus with the outside skin, or sometimes with the vagina. Rectal fistulas may connect the rectum with the skin, vagina or other internal organs within the body. Anal fistulas are generally formed by an infection or abscess that finds a way to drain through the skin, many times following drainage by a medical professional. This drainage however is required to treat the infection. Once a fistula forms, surgical management is usually required to repair and heal the fistula.
Causes of Anal Fistula
The most common cause of an anal fistula is the presence of an anal abscess that has either developed quickly or gone untreated for a while. Sometimes fistulas can also be the result of other diseases, such as Crohn’s disease, or anal fissures, from prior surgical procedures, or from exposure to radiation. In most cases, an infected anal gland leads to an abscess which drains or requires drainage to control the infection. If the gland does not heal, fecal material and pus may communicate from the anus through the abscess to the skin. Eventually the tunnel or tract becomes lined with tissue that may result in the persistence of the fistula. This process may occur in up to 50% of patients following an abscess.
Fistulas are a significant complication for anal abscesses for a few reasons. First, they require more complex surgical intervention than abscesses because of their different shapes and tracts they take relative to the sphincter muscles which provide control of stool. Secondly, an anal fistula can appear to the untrained eye to be an abscess, and can seem to drain, but the presence of the fistula tract increases the chance of recurrence unless the fistula is treated surgically.
Symptoms of Anal Fistula
Anal fistulas are typically preceded by anal abscesses, and the symptoms are generally similar. Symptoms of an anal fistula include:
- Severe pain, including throbbing sensations, particularly during bowel movements
- Swelling of the tissue in the anal area
- Discharge from the anus
- Secondary irritation in the anal area from discharge
- Fever or chills
Diagnosis of Anal Fistula
The first step in diagnosing an anal fistula, as with most diseases, is to have a clinical examination by a highly qualified professional. Your proctologist will talk with you about your symptoms, examine the site visually, and possibly recommend some testing to gather more information. In most cases, an exam under anesthesia is the method of choice to fully evaluate, and in many instances, treat the fistula. Care is taken to determine the location of the internal opening to the fistula and the length and course of the tract relative to the surrounding sphincter muscles. This is important so that any treatment maximizes the chance of success and preserves the function of the sphincters so as to have a minimal impact on control of the bowels. Sometimes, in more complex cases, or instances where the fistula can not be clearly define under sedation, imaging studies such as MRIs, CT scans, ultrasounds or x-ray tests with dye may be ordered. Additionally, a colonoscopy may be recommended to determine the presence of other associated conditions like Crohn’s disease (inflammation in the colon and rectum) which may require additional medical therapies.
Treatment of Anal Fistula
The most common surgical treatment method for anal fistulas is simple fistulotomy. A fistulotomy involves incision of the skin overlying the fistula and cleaning or debriding out the area in order to allow it to heal. This may be combined with removal of hemorrhoids or treatment of a fissure if necessary. Fistulotomy is most appropriate for short, superficial tracts that do not run deep to much of the sphincter muscles. Occasionally the approach may involve a gradual cutting of the tissue over weeks with the use of a special drain known as a seton. Fistulotomy has among the lowest rates of recurrence for fistula treatment; however because of the risks of incontinence when muscle is cut, it is not appropriate for all patients .
Patients with deeper or more complex fistula require alternative procedures to preserve sphincter function and continence. These procedures do not involve cutting of the sphincter muscle. In general, while muscular function is well preserved, success rates are lower than with fistulotomy. Several techniques exist to treat complex fistulas. The basic concept is to fill in or obliterate all, or part of the tract and closing the internal opening in the anus. In many instances, a staged approach with two procedures is undertaken; the first being the exam under anesthesia with placement of a drain or seton, the second procedure to repair the fistula follows several weeks to months later. Techniques include:
- Anal fistula plug – a bioabsorbable plug inserted into the fistula tract
- Fibrin glue – a biologic glue is used to fill the fistula tract
- Rectal Advancement Flap – a flap of rectal mucosa I brought down and stitched over the internal anal opening
- LIFT procedure – the inner and outer sphincter muscles are separated but preserved, and the fistula tract ligated and internal opening closed, sometimes with the placement of biologic mesh
- Muscle reconstruction – in vaginal fistula cases where the sphincters have been damaged from childbirth
- Long-term drainage setons – in cases where repair is unlikely to succeed , or with complex medical factors
Fistulas represent a complex problem for surgeons and patients due to the complexities of balancing surgical techniques and their success rates, with fecal control ,or continence. Typically, when there are multiple ways to address a problem it is because no one procedure has distinguished itself in all circumstances. Fistula surgery is no exception. Generally speaking, a recurrence rate of up to 10-15% can be seen with simple fistulotomy. Sphincter preserving procedures (plug, glue, flap, LIFT) have recurrence rates sited between 10% to 50% in the literature.
The Saleeby & Wessels Proctology Approach
At Saleeby and Wessels Proctology, we apply a conservative approach designed to maximize success and minimize sphincter disruption. This includes judicial use of fistulotomy for simple cases, many times employing a gradual cutting technique with a seton. In more complex cases, fistula plugs, advancement flaps and LIFT procedures play a key role, many times as part of a staged approach in our management of fistulas.
Fistulas can be a challenging surgical problem even to the most experienced surgeons due to the complexities of the evaluation, possible medical conditions, the need to preserve sphincter function, as well as the myriad of surgical approaches available. With our board certified colon and rectal surgeons and patient first approach, we possess the knowledge and experience necessary to offer patients the best options to treat fistulas.