Fissures

Longitudinal breaks in the squamous epithelium of the anal canal.

Fissures may be superficial or deep; deep fissures may expose the internal sphincter. An external skin tag (sentinel pile) often forms at the lower end of a chronic fissure (see Figure 109-1). The cause may be large or hard bowel movements, rough fecal debris, straining at stool, diarrhea, or trauma to the anal canal caused by rough wiping, foreign bodies (eg, thermometers, enema nozzles), or anoreceptive intercourse.

The main symptom is severe pain, which is aggravated by defecation, persists for several minutes afterward, and subsides until the next bowel movement. Massive bleeding is rare.

Diagnosis and Treatment

Fissures can usually be seen when the buttocks are separated and the patient strains. They usually occur at the posterior midline but occasionally occur at the anterior midline. If the fissure is not visible when the patient strains, anoscopy may be used (although few patients can tolerate the procedure). For some patients, the examination is so painful and causes so much spasm of the sphincter that local or general anesthesia is needed.

For superficial lesions, stool softeners (eg, psyllium hydrophilic mucilloid) and warm sitz baths may accelerate healing. Topical creams or ointments containing local anesthetics or simple protectants may provide relief when applied after bowel movements.

Chronic fissures require surgical intervention. Internal sphincterotomy, a relatively simple procedure using a local, regional, or general anesthetic, is most commonly performed. It relieves pain and allows healing. Division of the lateral anus (lateral sphincterotomy) is necessary, because it is much less likely to result in permanent incontinence than is posterior division. Other procedures pose a higher risk of permanent incontinence.