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.