Interesting X-ray 7
Finding :
Markedly dilatated colon loop with its resultant “omega loop” or “bent inner tube” sign,
which is sign of semoid volvulus.
Surgical point :
Sigmoid volvulus occurs most commonly in men, the elderly, and institutionalized patients.
In the latter groups, chronic constipation and the frequent use of laxatives or enemas are
believed to cause chronic distention with resultant elongation and redundancy of the sigmoid
and mesosigmoid; the latter changes predispose the bowel to twisting.
In cases of sigmoid volvulus, the freely mobile sigmoid rotates axially around the inferior
mesenteric vessels between the fixed proximal and distal colon; obstruction occurs after a
180-degree torsion. Although torsion can occur in either a clockwise or counterclockwise
direction, the counterclockwise direction is more common. The colon can also twist around
the bowel wall itself.
Treatment :
An urgent laparotomy is mandated if suspicion for ischemia is high (e.g., elevated body
temperature, leukocytosis, peritoneal signs, free abdominal air, significant acidosis, or early
sepsis). If obvious gangrene is found, detorsion is avoided and resection of the involved
segment with end colostomy and Hartmann's pouch is recommended. In more severe cases, a
second-look laparotomy may be necessary. If the bowel appears viable at laparotomy, a 180degree clockwise detorsion is performed. The bowel is then warmed and observed for pink
coloration, peristalsis, and palpable arterial pulsations.If the bowel is viable, resection with
primary anastomosis is then performed except in elderly patients with multiple comorbidities.
If signs or symptoms of bowel ischemia are absent, either rigid or flexible
proctosigmoidoscopy can be done. Both measures provide a safe means by which to examine
the bowel mucosa, as well as to decompress the dilated loop. The patient is placed in a lateral
decubitus position, and the endoscope is passed until the volvulus is encountered, usually 15
to 20 cm from the anal verge. The scope is then carefully advanced through the narrowed
area, often resulting in a rapid decompression of liquid stool and gas. Undue pressure must be
avoided to avoid perforation; the procedure should be aborted if there is any resistance.
Excess air and liquid are suctioned from the colonic lumen, after which a soft 25- to 32-F
rectal tube is inserted into the dilated lumen, maintaining decompression for 48 to 72 hours.
Because thr recurrence of sigmoid volvulus after endoscopic detorsion ranges from 30% to
90%; after decompression, many patients undergo colonic lavage as plans are made for
elective sigmoid resection during the same admission. The mortality of elective resection is
low (1%–5%), with an equally low recurrence rate (∼5%).