Anal Fistula


Anal Fistula
Anal fistula is one of the common anorectal diseases. It is an inflammatory tunnel under the skin, connecting the anal canal and the surface of the surrounding skin. 80% occur as a result of an anorectal infection, wherein the anal crypts are infected and cysts containing pus form near the anal canal. If the abscess breaks or is opened a fistula is often formed.

The diagnosis of anal fistula can be easily made by detecting the external opening of an anal fistula. Anal fistulas are classified by their location in relation to the anal sphincter muscles (intersphincteric transphincteric, suprasphincteric, and extrasphincteric fistula). Doctors may use anoscope and a probe to identify the fistula path. If a fistula appears particularly complicated or in an unusual place, doctors may also do the fistulography and colonoscopy for further evaluation.

These are four common fistulas;

  • Intersphincteric- 45% of cases
  • Transsphincteric- 30% of cases
  • Suprasphincteric- 20% of cases
  • Extrasphincteric- 5% of cases
  • These distinctions are based on the location and path of the fistula, which is seen above. This is called the Parks classification. Superficial fistulas are different from the other four in that the tracks are not linked to the anal canal or the sphincter, so are not included in the Parks classification. Anal fistulas can be described as simple or complex. Simple fistulas are low transsphincteric and intersphincteric fistulas. Complex fistulas describe any other type of anal fistula, which can take many shapes, sizes, depths, and can branch off.

    Symptoms of an uninfected anal fistula can manifest as drainage from the opening of fistulas and itching around anus, and anal fistulas with infection cause fever and returning abscesses with a constant, throbbing pain, and the symptoms are exacerbated by movement, passage of stool, and coughing/sneezing. This can make rectal examination difficult without topical anesthetic, and even then many patients may not be able to tolerate it. In cases like this, where digital rectal examination is not possible or inconclusive, more advanced diagnostic methods may be necessary.

    It is important to treat an anal fistula to relieve the symptoms and prevent re-infection. The goal of treatment is to cure the fistula with as little impact as possible on the sphincter muscles.

    Treatment varies depending on the severity and location of the fistula. Antibiotics, antipyretics and, pain medication is prescribed if there is drainage (indicating abscess). For simple rectal abscesses, antibiotics are usually not needed. With this condition, it is better to seek help sooner than later. Advanced abscesses that become complex are much more difficult to treat. For most however, it seems procrastination is not much of a problem- pain is a very effective motivator.

    The surgical procedure for simple fistulas are called a fistulotomy or fistulectomy, where the fistula tract is cleared out or removed surgically and allowed to heal properly. For simple fistulas, success rate with fistulotomy is over 90%. More complex fistulas may be to twisted or branching for a fistulotomy so fibrin glue or fibrin plug may be used instead. Though in common, staged surgery may be needed.

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    Fistulotomy: The surgeon first probes to find the fistula’s internal opening. Then the surgeon cuts the tract open and curettes it, then the wound left open or it is stitched in a way that the fistula is laid open.

    Fistulectomy: The surgeon may lay open only the segment where the tracts join and remove the remainder of the tracts. The surgery may be performed in more than one stage or repeated if the entire tract can’t be found.

    For the complicated anal fistula, you will be referred to see a colorectal surgeon for the further evaluation and treatment. The treatment options include Fistulectomy with Advancement Rectal Flap, Seton Placement, and Fibrin Glue.

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