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FISSURE-IN-ANO

This is crack in the extremely sensitive mucous membrane of the anal canal. The condition is very painful and this pain causes spasm of the underlying internal sphincter. As long as this spasm remains, the crack in the overlying mucosa does not heal. Thus a vicious cycle is set up. Hence, a fissure, which to start with is acute, becomes chronic.

Fissures are commonest in the midline posteriorly. In males 90% occur posteriorly and 10% anteriorly, in the midline. In females, the incidence is 60% and 40% respectively. The relative frequency of the anterior fissures in the females may be explained by the trauma caused by the foetal head on the anterior ano-rectal wall. The overall frequency of the posterior fissures can be explained by the natural curvature of the anal canal. Constipation, therefore, is a common etiological factor.

Description:
To start with, fissure is a superficial ulcer. As it gets chronic, it becomes converted into a canoe-shaped ulcer. At its upper end there is frequently a hypertrophic anal papilla. At its lower end a tag of hypertrophic skin hangs. This is called the Sentinel Pile (sentinel=sentry), and this is found only with long-standing fissures. A constant feature is a severe spasm of the internal sphincter, felt by digital examination. Frequently, a small subcutaneous fistula underlies the sentinel pile.

Types:
  • Acute: Superficial crack with thin margins
  • Chronic: A deeper ulcer, sometimes exposing the internal sphincter at its base. The margins are thick and oedematous. Usually there is an associated sentinel pile
Clinical Features:
Typically, the patient presents with severe pain, during and after defaecation, often associated with a few drops of fresh blood with the stool. A history of constipation is very common.

Treatment:
  • In acute cases: A conservative treatment is often successful:
    • Use of laxatives and application of a local analgesic ointment
    • If this does not work, injection of a local anaesthetic agent in an oily base (for prolonged effect) into the tissues around the fissure (to relieve pain) and into the internal sphincter (to allay spasm). The disappearance of the spasm lasts for two to three weeks, by which time the fissure often heals. If required, the procedure may be repeated
    • If the injection therapy fails, forcible digital stretching of the internal sphincter, done under general anaesthesia, often succeeds in curing the condition
  • In Chronic Cases: operative treatment has to be undertaken. The different operations, practiced, are as follows:
    • Internal Sphincterotomy: A Sims’s speculum is introduced and anal canal is opened up to expose the fissure. At its base, the fibres of the internal sphincter are seen. These fibres are cut through, in one line, till the conjoined longitudinal muscle is seen. Sentinel pile, if there be any, is also excised
    • Excision of the Fissure: the whole length of the fissure, together with sentinel pile and a little of parianal skin around it, is excised in the shape of a wedge. The wound is allowed to heal by granulation
    • Excision of the Fissure with Sphincterotomy: This is the most commonly practiced procedure. After the fissure is excised, a sphincterotomy is also performed as described above
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This article has been written by Dr. M. Javed Abbas.
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01:23 10/02/2003