Volvulus

A volulus is a twisting or axial rotation of a portion of bowel about its mesentery. When complete it forms a closed loop of obstruction with resultant ischaemia secondary to vascular occlusion.

Volvuli may be primary or secondary. The primary form occurs secondary to congenital malrotation of the gut, abnormal mesenteric attachments or congenital bands. Examples include volvulus neonatorum, caecal and sigmoid volvulus. A secondary volvulus, which is the more common variety, is due to actual rotation of a piece of bowel around an acquired adhesion or stoma.

Volvulus neonatorum is predisposed to by arrested gut rotation with a resultant narrow mesentery of the small bowel and caecum. The symptoms are similar to arrested rotation (vide in Ira) with repeated vomiting, hut the onset is more catastrophic with abdominal distention and rapid dehydration. Abdominal radiography reveals evidence of duodenal obstruction. Laparotomy reveals a distended stomach and coils of small bowel (Fig. 58.19). The whole midgut should he delivered to the wound and wrapped in warm, moist towels, in order to demonstrate the volvulus which usually occurs in a clockwise direction. The operation consists of reduction by untwisting and division of any secondary obstructive lesions — such as the transduodenal band of Ladd.

Volvulus of the small intestine

This may be primary or secondary and usually occurs in the lower ileum. It may occur spontaneously in Africans, particularly following consumption of a large volume of vegetable matter, whilst in the West it is usually secondary to adhesions passing to the parietes or female pelvic organs. Treatment consists of reduction of the twist and is then directed to any underlying cause.

Caecal volvulus

This may occur as part of volvulus neonatorum or de novo and is usually a clockwise twist. It is more common in females and usually presents acutely with the classic features of obstruction. At first the obstruction may be partial with the passage of flatus and faeces. In 25 per cent of cases, examination may reveal a palpable tympanic swelling in the midline or left side of the abdomen. Plain radiograph may reveal a gas-filled ileum and occasionally a distended caecum. A barium enema may be used to confirm the diagnosis with an absence of barium in the caecum and a bird beak deformity.

At operation the volvulus should be reduced. Sometimes this can only be achieved after decompression of the caecum by a needle. Further management consists of either fixation of the caecum to the right iliac fossa (caecopexy) and/or a caecostomy. If the caecum is ischaemic or gangrenous a right hemicolectomy should be performed.

Sigmoid volvulus

This is rare in Europe and the USA but more common in Eastern Europe and Africa; indeed it is the commonest cause of large bowel obstruction in indigenous black Africans (Loefler). The predisposing cause is summarised in Fig. 58.18. Rotation nearly always occurs in an anticlockwise direction. Predisposing factors include high residue diet and chronic constipation. The symptoms are of large bowel obstruction which may initially be intermittent, followed by the passage of large quantities of flatus and faeces. Presentation varies in severity and acuteness, with younger patients appearing to develop the more acute form. Abdominal distension is an early and progressive sign which may be associated with hiccough and wretching; vomiting occurs late. Constipation is absolute. In the elderly a more chronic form may be seen. A plain radiograph shows massive colonic distension. The classic appearance is of a dilated loop of bowel running diagonally across the abdomen from right to left with two fluid levels seen, one within each loop of bowel.

Treatment

Flexible sigmoidoscopy or rigid sigmoidoscopy and insertion of a flatus tube should be carried out to allow deflation of the gut. Success, as long as ischaemic bowel is excluded, will provide temporary respite allowing resuscitation and an elective procedure. Failure results in an early laparotomy, with untwisting of the loop and per-anal decompression (Fig. 58.19). When the bowel is viable, fixation of the sigmoid colon to the posterior abdominal wall may be a safer manoeuvre in inexperienced hands. Resection is preferable if it can be achieved safely. A Paul—Mikulicz procedure is a useful procedure particularly if there is suspicion of impending gangrene (Fig. 58.20). An alternative is a sigmoid colectomy and, where anastomosis is considered unwise, a Hartmann’s procedure with subsequent reanastomosis.

Compound volvulus

This is a rare condition also known as ileo-sigmoid knotting. The long pelvic mesocolon allows the ileum to twist around the sigmoid colon resulting in gangrene of either or both segments of bowel. The patient presents with acute intestinal obstruction, but distension is comparatively mild. Plain radiography reveals distended ileal loops in a distended sigmoid colon. At operation decompression, resection and anastomosis are required.