The twisted colon: a review of sigmoid volvulus

Sigmoid volvulus (SV) is the third leading cause of colon obstruction in adults. In infants and children, it is exceedingly rare with only sporadic cases reported so far. SVs from secondary causes, with congenital megacolon being the most important, are nevertheless more common in young people. The etiology of this disorder is not completely understood. It is known to occur in the setting of redundant sigmoid loop, which rotates around its narrow and elongated mesentery. Although the latter occurs in the setting of constipation, a congenitally elongated colon, and other predisposing factors, there is no consensus on the precipitating factor leading to SV formation. The symptoms are suggestive of small bowel obstruction, but the presentations can be acute or indolent. Plain abdominal radiography is used to diagnose SV in most cases with computed tomography scan or magnetic resonance imaging as the confirmatory tests when necessary. After it has been untwisted, the definitive and standard therapy for SV is sigmoid resection and primary anastomosis. The nonresective alternatives have also been widely used with mixed success, but a large, randomized controlled trial is needed to compare their efficacy with resection and primary anastomosis. Laparoscopic surgery in SV management is unwarranted and costly. Complications of SV include hemorrhagic infarction, perforation, septic shock, and death. The mortality data from SV vary, but the latest literature cites an overall range of 14 to 45 per cent.