Anal Fistulotomy

Chapter 29 Anal Fistulotomy

Eugene F. Foley, MD

INTRODUCTION

The surgical treatment of perianal fistulous disease is one of the most common, minor, benign anorectal procedures performed by the general surgeon. Despite its frequency and “size,” the appropriate balance between resolution of the troubling symptoms of persistent fistulas and the potential for devastating functional consequences with overly aggressive surgical treatment of fistulas can be very challenging. The major elements of successful anal fistulotomy surgery are described later, with emphasis on the reduction of specific complications.

INDICATIONS

Although not all surgically drained perianal or perirectal abscesses will result in a chronic fistula-in-ano, it is estimated that as many as 50% will.1 The symptoms of a persistent fistula include recurrent abscess formation, chronic perianal drainage, and pain. The diagnosis of a persistent fistula-in-ano in most patients is an indication for consideration of fistulotomy to reduce or eliminate these chronic symptoms and the frequency of recurrent abscess formation. Notable exceptions would include patients with complex fistulas due to Crohn’s disease, perineal radiation, or uncontrolled distal gastrointestinal tract or gynecologic malignancy.

OPERATIVE STEPS

Step 1 Anesthetic considerations
Step 2 Examination and identification of internal opening
Step 3 Assessment of sphincter complex in relation to fistula track
Step 4 Incision of fistula

OPERATIVE PROCEDURE

Anesthetic Considerations

Urinary Retention

Urinary retention is one of the most common complications of all anorectal surgery. The extent and complexity of surgery correlates with the incidence of this complication. A large institutional study has reported the incidence of urinary retention after fistula surgery as 5%.2

• Consequences

Postoperative urinary retention may lead to the need for urinary catheterization, delaying the discharge of patients after this day-surgery procedure. It may also require emergent reevaluation of the patient later in the day after surgery.
Grade 1/2 complication

• Repair

Urinary retention after anorectal surgery is treated by temporary urinary catheterization, usually over a 24- to 48-hour period. Conservative measures, including voiding while submerged in a tub of warm water, may avoid the need for catheterization. Formal urologic evaluation is reserved for the minority of patients who fail these measures, usually those with preoperative urologic difficulties.

• Prevention

Judicious use of perioperative intravenous fluid has been shown to decrease this complication after hemorrhoidectomy.3,4 Although not conclusively shown in the literature to reduce this rate after fistula surgery, analogous recommendations of limiting overdistention of the bladder with excessive intravenous fluid and the liberal use of local anesthetic (bupivacaine [Marcaine]) to decrease postoperative levator spasm seem reasonable.

Examination under Anesthesia and Identification of the Internal Opening

Failure to Identify the Internal Opening

Finding the internal opening of the fistula-in-ano is the first of two critical steps in the successful surgical treatment of a fistula. Benign fistulas are the result of crypt-glandular infection at the dentate line and are perpetuated by a persistent internal opening at the inciting gland at the dentate line.

• Consequence

Failure to identify the internal opening of the fistulain-ano will result in failure of the surgery to correct the problem, resulting in persistent symptoms of recurrent abscess formation or perianal drainage. Fistula surgery should be successful in 85% to 90% of cases.5
Grade 2/3 complication

• Repair

If the internal opening is not found, the external opening and track should be opened and débrided, to improve drainage. Attempts at blindly cutting or forcing the fistula probe through the dentate line without seeing an internal opening are unlikely to resolve the fistula and more likely to damage the underlying sphincter complex. If the internal opening is not identified or opened, recurrent symptoms will likely mandate another operative exploration at a later date.

Related posts:

  1. Isolated Limb Perfusions and Extremity Amputations
  2. Lateral Pancreaticojejunostomy (Puestow) Procedure
  3. Left Colectomy: Open and Laparoscopic
  4. Bronchial and Vascular Sleeve Lobectomy

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Jun 21, 2017 | Posted by in GENERAL SURGERY | Comments Off on Anal Fistulotomy

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