Surgery for Volvulus

Graham Williams

Powerpoint File

Volvulus of the colon involves twisting of the bowel on its mesenteric axis, resulting in complete or partial obstruction to the bowel and potential compromise of the blood supply to the colon. Volvulus of the colon is an uncommon cause of large bowel obstruction responsible for about 5% of cases of large bowel obstruction in the UK. The commonest site of colonic volvulus is the sigmoid colon, accounting for 63% of cases of colonic volvulus with the caecum and right colon next commonest (33%) and the transverse colon (3%) and splenic flexure (1%) uncommon sites of volvulus.

The incidence of volvulus varies greatly in different geographical regions, with different age groups affected, reflecting differing aetiological factors. For volvulus to occur, the colon must be long, mobile and redundant, with a narrow mesenteric base around which the bowel can rotate. In Western society, sigmoid volvulus is seen predominantly in elderly patients: often those confined to institutions because of old age or mental incapacity. Enlargement of the colon is thought to result from a combination of chronic constipation and use of psychotropic medication. In a proportion of patients sigmoid volvulus will occur as a complication of acquired megacolon. Pregnancy is recognised to be an aetiological factor, with volvulus arising as the sigmoid colon is pushed upwards by the expanding uterus. Caecal volvulus is more common in females and is related to abnormal mobility of the caecum and ascending colon, which can be congenital but is also related to chronic constipation. In developing countries, sigmoid volvulus is a more common cause of large bowel obstruction, which occurs in younger patients and is thought to be related to dietary factors. In South America, acquired megacolon as a result of Chaga’s disease is a common cause of volvulus.

Volvulus presents as acute or subacute large bowel obstruction. Typically the history is of a sudden onset of abdominal pain, absolute constipation and gross abdominal distension. There may be a history of previous episodes which may have settled spontaneously or required hospital treatment. The abdomen is very distended and resonant. Tachycardia, absent bowel sounds, passage of blood stained mucus and tenderness or guarding indicate that infarction of the colon may have occurred. Abdominal X-rays are usually diagnostic, although sometimes challenging to interpret because of the colonic distension. In sigmoid volvulus, the sigmoid is markedly dilated and appears like a bent inner tube, arising from the left iliac fossa. In caecal volvulus, the gas shadow assumes a comma shape, which faces inferiorly to the right iliac fossa. Water soluble contrast study is sometimes required to differentiate volvulus from pseudobstruction.

Management of Sigmoid volvulus

Once the diagnosis is made, management is determined by the likely presence of infarction of the colon, which occurs in about 10% of cases in developed countries and 25% of cases in developing countries and is associated with much higher mortality rates. Where infarction is suspected, urgent laparotomy and resection is required after fluid resuscitation. Primary anastomosis can be considered in fit patients, but the safer option is to perform Hartmann’s resection, especially in the old and frail.

In uncomplicated sigmoid volvulus, current practice is to attempt non operative decompression in the acute situation. Traditionally this was performed by a lubricated rectal tube, eased through the twist in the colon at rigid sigmoidoscopy. This technique is successful in 2/3rds of patients and can easily be performed in the ward. If unsuccessful, non operative decompression can be performed using a colonoscope, gently pushing the end of the instrument through the twist into the dilated sigmoid. Aspiration of the gas within the volvulus usually reduces the twist and resolves the acute situation. Success rates of over 90% have been reported for this technique, although it does require timely access to the endoscopy unit.

Non operative decompression usually can resolve the acute volvulus, however high recurrence rates of upwards of 90% have been reported, together with a mortality rate of 15% for recurrent volvulus. For this reason consideration has to be given to definitive treatment of the volvulus after decompression. A variety of techniques have been employed, including:- resection of variable quantities of colon, with primary anastomosis or colostomy, fixation of the mobile colon to the abdominal wall or transverse colon (colopexy), attention to the long narrow mesentery (mesosigmoidoplasty). Newer approaches include laparoscopic fixation or resection and percutaneous endoscopic colopexy using the colonoscope and percutaneous endoscopic gastrostomy kits.

Resection of the redundant sigmoid colon can usually be performed though a small incision in the left iliac fossa. Anastomosis (if performed), can be a challenge because of size discrepancy and a variety of stapled techniques have been described. In the presence of megacolon, sigmoid resection alone is associated with a high recurrence rate and more extensive resection is required to prevent recurrence. Subtotal colectomy and ileo-rectal anastomosis or caeco-rectal anastomosis should be considered it the patient is fit enough to undergo the more extensive procedure.

The role of lesser procedures such a colopexy or mesosigmoidoplasty remains uncertain. These operations are lesser procedures than colonic resection and can avoid the need for a stoma in a patient where this would be a significant burden. However, recurrence rates after these procedures appear to be higher than after sigmoid resection.

Management of Caecal Volvulus

Non operative reduction of caecal volvulus is not usually successful and laparotomy is required to deal with the problem. Ischaemia of caecal volvulus is less common than for sigmoid volvulus. Simple de-rotation of the volvulus alone is associated with a high recurrence rate. Some form of fixation procedure is required. Caecopexy, with and without a peritoneal flap has been a popular approach, but recurrence rates of up to 30% have been described. Tube caecostomy, with or without suture fixation, is another method of sticking the caecum in the right iliac fossa, although this is not without complications. An alternative approach is to perform right hemi colectomy. The procedure is usually straight forward because of the mobility of the right colon, but there is a risk of anastomotic complications. Recurrence after right hemicolectomy is unusual. A pragmatic approach to the problem is to perform fixation in frail patients and resection and anastomosis in fitter patients.