Sigmoid volvulus

Intestinal volvulus refers to partial or complete occlusion of the intestinal lumen caused by rotation of a colonic loop around its mesentery as the fixed point along the long axis of the mesentery. The volvulus is generally clockwise. Obstruction can occur when the twist exceeds 180°. Mild torsion may be less than one full turn (360°), while severe cases can reach 2-3 turns. After onset, on the one hand, intestinal lumen narrowing and obstruction can occur; on the other hand, strangulation can occur due to compression of mesenteric vessels. Sigmoid volvulus is a closed-loop intestinal obstruction. The twisted intestinal loop often becomes highly dilated and distended. When the intestinal wall is excessively distended, patchy tension necrosis or perforation can also occur.