Acute volvulus of the colon is a surgical emergency and although accounting for not more than 5 per cent of all cases of large bowel obstruction in the Western world (Fig. 1) 1103, it is a much more common cause of large bowel obstruction in other parts of the world. The incidence of the various types of colonic volvulus is shown in Fig. 2 1104: sigmoid volvulus is by far the most common, accounting for about two-thirds of all cases. Caecal volvulus accounts for most of the remaining cases, while volvulus of the tranverse colon and splenic flexure are very rare indeed. A simultaneous volvulus of the sigmoid and right colon has been reported. Together sigmoid and caecal volvulus represent over 90 per cent of cases of colonic volvulus.

The presence of an elongated mesentery about which the bowel can rotate is fundamental to the pathogenesis of colonic volvulus. Although a mesentery is a normal feature of the sigmoid colon, a caecal volvulus can only occur if the usual fixation of the caecum in the right iliac fossa has not occurred during development. Although many of the features of the different kinds of colonic volvulus are similar, important differences exist and so they are best considered separately.

Sigmoid volvulus is common in the continents of India, Africa, parts of South America, and in Eastern Europe, where it has been shown to be responsible for up to 50 per cent of all cases of intestinal obstruction. In Western Europe and North America, however, it is uncommon, accounting for about 5 per cent of all cases of large bowel obstruction. The incidence in one large reported series in New York was 1.3 per 10000 hospital admissions.

It is thought that the major contributing factor in those parts of the world where there is a high incidence is the high dietary fibre content. Other factors which are recognized to be important are a long redundant colon, an acquired megacolon, chronic constipation, and a narrowly based mesentery.

The peak age incidence of sigmoid volvulus is in the eighth decade, with 70 per cent of patients presenting after 70 years of age and up to 40 per cent of patients being over 80 years old. A high proportion of patients presenting with acute sigmoid volvulus (up to 60 per cent) are institutionalized. The condition is particularly common in elderly patients suffering from psychiatric and chronic neurological diseases such as stroke or multiple sclerosis. Other conditions with which it tends to be associated include cardiovascular disease and diabetes.

The condition usually presents with acute colicky abdominal pain, almost invariably associated with distension and, in one-half of all patients, with constipation. These features in an elderly person with a chronic psychiatric or neurological complaint should immediately raise the possibility of sigmoid volvulus. On examination, the most striking finding is of a tensely distended, tympanitic, ‘drum-like’ abdomen. The rectum is empty of stool. Bowel sounds are often increased but signs of peritoneal inflammation such as rebound tenderness or guarding are unusual. When these signs are present they suggest that colonic infarction or gangrene has occurred. Signs of dehydration may be apparent if presentation has been delayed and these should always be sought.

The most useful investigation of patients suspected of having a sigmoid volvulus is a plain supine abdominal radiograph. This alone may be diagnostic in 70 to 80 per cent of patients. The typical appearance is that of a single grossly distended loop of colon arising out the pelvis and extending towards the diaphragm. Haustral markings are usually lost (Fig. 3) 1105.

Investigation by a contrast enema such as dilute barium or a water-soluble contrast medium will increase the diagnostic yield of radiology to over 90 per cent of patients. If gangrenous bowel or perforation is suspected a water-soluble contrast must be used rather than barium, as the latter will produce a severe peritonitis. The pathognomonic sign on a contrast enema is described as a ‘birds beak’ or ‘ace of spades’ appearance, produced as the upper end of the barium column tapers into the spirally twisted distal sigmoid colon.

Most patients can be treated initially by non-operative means. Careful rigid sigmoidoscopy and the passage of a flatus tube via the sigmoidoscope is successful in up to 90 per cent of cases, and is well worth trying in the first instance. Protective clothing is recommended as the results of a successful decompression are usually explosive. A mortality of between 1 and 4 per cent is reported for the treatment and great care is essential if colonic perforation is to be avoided. Following a successful deflation, the flatus tube should be left in place for at least 48 h, and some would recommend as long as 5 days. Unless this is done the likelihood of an early recurrence is very high (50–90 per cent).

The alternative to endoscopic deflation is emergency surgery, but this is associated with a mortality of up to 40 per cent. Mortality is higher for sigmoid resection (52 per cent in one reported study by Welch and Anderson in 1987) than for operations aimed at fixing the mobile colon (colopexy) which had a 2.8 per cent mortality. However, the 28 per cent incidence of recurrence reported to follow sigmoid colopexy mitigates against it as an approach. In the minority of patients who have signs of infarction and peritonitis, emergency surgery should not be delayed, but in most cases early treatment should be non-surgical, surgery being reserved for those in whom this fails.

The emergency operation of choice is sigmoid exteriorization and resection, using a modification of the Paul–Mickulicz technique (Fig. 4) 1106. After resuscitation with intravenous fluids, antibiotic prophylaxis (such as a cephalosporin and metronidazole) is given before inducing general anaesthesia. The twist in the colon is reduced through a midline incision. It is helpful to remove gas from the colon by puncturing the bowel wall with a small (19 gauge) intravenous needle attached to the suction apparatus. This makes the bowel easier to handle and less likely to be torn or damaged during handling. A second smaller skin incision is made in the left iliac fossa through which the collapsed, freely mobile, sigmoid colon can easily be exteriorized. At this stage the future afferent and efferent loops of colon should be opposed and sutured together close to the abdominal wall, preparing the bowel for what will become a ‘double-barrelled’ colostomy. The midline abdominal incision is closed. The sigmoid colon is excised outside the abdomen and the double-barrelled colostomy is completed. Care must be taken when dividing the mesentery at this point to secure and ligate all of the blood vessels, as the large sigmoid branches of the inferior mesenteric artery can easily slip back into the abdominal cavity causing troublesome haemorrhage.

This problem can be avoided by dividing the mesentery at the level of the abdominal wall, inside the abdomen, prior to closure. The two lumens of bowel are divided and the mucosa is sutured to the skin to form the colostomy.

Unlike the original Paul–Mickulicz operation an enterotomy clamp is not used to close the colostomy, but a single one-stage closure is performed approximately 6 to 8 weeks following the original operation. Because of the close approximation of the afferent and efferent limbs, a full laparotomy is not necessary in order to do this.

An alternative operation in the emergency situation is the Hartmann procedure, in which the distal bowel end is closed within the pelvis following sigmoid colectomy. This operation has no advantages in the management of sigmoid volvulus when the distal and proximal ends of bowel can be easily approximated. It has the disadvantage that the second operation to reanastamose the bowel is very difficult. Sigmoid colectomy and primary anastomosis is not usually recommended in the emergency situation, but may be an alternative for an experienced colonic surgeon using ‘on-table’ antegrade colonic irrigation via caecal intubation to clean the bowel of faeces before anastomosis. Patients who develop recurrent volvulus after non-operative, or rarely after emergency operative treatment should be offered elective surgery, as there is a reported mortality of over 20 per cent for patients who continue to be managed conservatively. The operation of choice is sigmoid colectomy and primary anastomosis after a suitable preoperative bowel preparation. This can be achieved by giving patients clear fluids only by mouth for 48 h before surgery and two doses of sodium picosulphate on the day before operation.

Caecal volvulus is much less common than volvulus of the sigmoid colon, accounting for less than 1 per cent of all cases of intestinal obstruction and up to 40 per cent of all cases of colonic volvulus. In a reported series from Scandinavia the incidence was 3 to 6 per million per year. It carries a mortality of 20 per cent. In this condition the caecum remains mobile and shares a common mesentery with the ileum. It is therefore free to rotate, usually clockwise, out of the right iliac fossa to the mid- or left side of the upper abdomen (Fig. 6) 1108, producing a closed loop obstruction of the ascending colon and distal ileum.

Caecal volvulus may present as a fulminant condition with intestinal strangulation secondary to mesenteric torsion or, less dramatically, with features of intestinal obstruction. Rarely it is a chronic intermittent condition. The peak age of presentation is 30 to 40 years of age—much younger than that for sigmoid volvulus, and it is more common in females. There often appear to have been a triggering event, such as a recent laparotomy and it is well recognized following gynaecological procedures. Occasionally it can occur secondary to an obstructing colonic carcinoma and, like sigmoid volvulus, it may be related to a high fibre intake. The presenting symptoms are usually non-specific. Abdominal pain is almost invariably present and nausea, vomiting, constipation, and distension will occur in about one-third of patients. In thin patients it may be possible to palpate the resonant distended caecum in the central or upper abdomen while the right iliac fossa is empty.

The key to the diagnosis of caecal volvulus, as with sigmoid volvulus, is the plain abdominal radiograph. The caecum typically assumes a gas-filled ‘comma shape’ facing inferiorly and to the right (Fig. 7) 1109. In a retrospective analysis Anderson and Mills (1984) found that the diagnosis was evident on the plain abdominal radiograph in 40 out of 45 patients with caecal volvulus. The diagnosis is usually made in around 50 per cent of patients however. Other radiological appearances are of non-specific colonic obstruction or of small bowel obstruction. A barium enema may be useful to exclude any other predisposing colonic lesion and on occasions it has been effective in reducing the volvulus.

The mainstay of treatment for this condition is surgery and, unlike sigmoid volvulus, endoscopic deflation has little place. Prompt caecal resection is mandatory in those with caecal perforation or infarction and this is usually possible with a primary ileocaecal anastomosis. In severely ill patients, however, it may be expedient to exteriorize the proximal and distal bowel ends following resection, as an ileostomy and mucous fistula. These can then be anastomosed at a second operation 6 weeks later. The mortality in patients with gangrenous bowel is as high as 40 per cent.

The management of patients who present with caecal volvulus without evidence of strangulation is less clearly defined. Fixation of the caecum (caecopexy) to prevent recurrent torsion has its advocates. This is best achieved by combining suture fixation to the lateral abdominal wall with stripping of the parietal and visceral peritoneum to create raw surfaces that will stick firmly and permanently together. Unfortunately the technique has a recurrence rate of up to 20 per cent. The addition of a tube caecostomy has been advocated in addition to caecopexy and this has been shown to reduce the recurrence rate. However this addition is associated with an increase in surgical morbidity, mainly from septic problems from leakage, such as cellulitis, wound infection, and occasionally necrosis of the abdominal wall. The caecostomy tube can be removed after 1 week and the tract will normally close spontaneously within a few days. Occasionally, however, discharge of ileal contents persists, requiring further surgery formally to close the hole or resect the caecum.

The definitive treatment of caecal volvulus, even when the bowel is viable, is caecal resection and primary ileocolic anastomosis. If the surgeon has sufficient experience this is the preferred management. Whichever method is chosen, and the differing opinions would suggest that there is little between the options, prompt treatment is essential to prevent bowel strangulation.

Volvulus of the splenic flexure is extremely rare, accounting for less than 1 per cent of colonic volvuli, and it results from a congenital absence of one or more of the ligaments which normally fix that part of the bowel. The patients present with acute intestinal obstruction usually with a preceding history of chronic constipation. The diagnosis is made by diagnostic enema. Endoscopic deflation is often possible, but the patient should undergo definitive bowel resection to prevent recurrence.

Transverse colon volvulus is also very rare. It occurs when a degree of malrotation exists and can also result from chronic constipation, which leads to elongation of the mesentery. The mechanisms are similar to those involved in sigmoid volvulus. The clinical presentation is usually subacute or chronic but patients can present with an acute fulminant condition requiring emergency surgery. For this reason when the diagnosis is suspected a barium enema should be performed and prompt elective resection undertaken.

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