Nonmalignant strictures Congenital

A stricture at the level of the anal valves, due to incomplete obliteration of the proctodeal membrane, sometimes does not give rise to symptoms until early childhood.

Patients who have had an operation for imperforate anus in infancy may require periodic anorectal dilatation.

Spasmodic

  An anal fissure causes spasm of the internal sphincter.

Rarely, a spasmodic stricture accompanies secondary megacolon (Chapter 57), possibly due to chronic use of laxatives.

Organic

  Postoperative stricture sometimes follows haemorrhoidectomy performed incorrectly. Low coloanal anastomoses, especially if a stapling gun is used, can narrow down postoperatively.

  Irradiation stricture is an aftermath of irradiation.

  Senile anal stenosis — a condition of chronic internal sphincter contraction is sometimes seen in the aged. Increasing constipation is present with pronounced straining at stool. Faecal impaction is liable to occur. The muscle is rigid and feels like a tight umbrella ring. There is no evidence of a fissure in ann. The treatment is internal sphincterotomy or dilatation at frequent intervals.

  Lymphogranuloma inguinale (Chapter 67). This is by far the most frequent cause of a tubular inflammatory stric­ture of the rectum and 80 per cent of the sufferers are women. Frei’s reaction is usually positive. This variety of rectal stricture is particularly common in black races, and may be accompanied by elephantiasis of the labia majora. In the early stages, antibiotic treatment may lead to cure. In advanced cases excision of the rectum is required.

Inflammatory bowel disease. Stricture of the anorectum also complicates ulcerative proctocolitis and most common­ly large-bowel Crohn’s disease; in this instance the stricture as annular and often more than one is present. A carcinoma should be suspected if a stricture is found, until a biopsy is obtained.

  Endometriosis of the rectovaginal septum may present as a stricture. There is usually a history of frequent menstrual periods with the appearance of severe pain during the first 2 days of the menstrual flow

   Neoplastic. When free bleeding occurs after dilatation of a supposed inflammatory stricture, carcinoma should be suspected (Grey Turner) and a portion of the stricture should be removed for biopsy. Sometimes in these cases repeated biopsies show inflammatory tissue only. If, however, the symptoms show a marked progression, malignancy should be strongly suspected.

Clinical features

Increasing difficulty in defecation is the leading symptom. The patient finds that increasingly large doses of aperients are required, and if the stools are formed, they are ‘pipe-stem’ in shape. In cases of inflammatory stricture, tenesmus, bleeding  and the passage of mucopus are superadded. Sometimes the patient comes under observation only when subacute or acute intestinal obstruction has supervened.

Rectal examination. The finger encounters a sharply defined shelf-like interruption of the lumen. If the calibre is large enough to admit the finger, it should be noted whether the stricture is annular or tubular. Sometimes this point can be determined only after dilatation. A biopsy of the stricture must be taken.

Treatment

Prophylactic

The passage of an anal dilator during convalescence after haemorrhoidectomy greatly reduces the incidence of post­operative stricture. Efficient treatment of lymphogranuloma inguinale in its early stages should lessen the frequency of stricture from that cause.

Dilatation by bougies

For anal and many rectal strictures dilatation by bougies at regular intervals is all that is required.

Anoplasty

The stricture is incised and a rotation or advancement flap of skin and subcutaneous tissue replaces the defect and enlarges the anal orifice (Fig. 61.44). This technique is particularly useful for postoperative strictures.

Colostomy

Colostomy must be undertaken when a stricture is causing intestinal obstruction, and in advanced cases of stricture complicated by flstulae in ann. In selected cases, this can be followed by restorative resection of the stricture-bearing area. If this step is anticipated, the colostomy is placed in the transverse colon.

Rectal excision and coloanal anastomosis

When the strictures are at or just above the anorectal junc­tion, and are associated with a normal anal canal, but irre­versible changes necessitate removal of the area, excision can be followed by a coloanal anastomosis with good functional results. A similar procedure can be done for an otherwise incurable supralevator fistula, especially post irradiation.