Neglected role of torsion and constriction in pathogenesis of simple adhesive bowel obstruction.

We critically analysed the mechanism of simple adhesive bowel obstruction in 88 re-laparotomies for this condition, paying special attention to obstructing factors beside angulation. Twenty-six obstructions were caused by bowel-to-bowel adhesion, and 42 by adhesion of bowel to other structures, whereas in the remaining 20 these two types were combined. Although angulation was almost always found at the site of obstruction, torsion (twisting of bowel about its axis) was detected in 25 of the 33 in situ observations, usually accompanied by various degrees of organic constriction. In bowel-to-bowel adhesion, the torsion and constriction were produced by a unique relation of the bowel to the adhesion; the latter connected one side of the mesenteric margin to the opposite side, encircling the bowel wall obliquely. This was never seen on nonobstructing adhesions. We conclude that torsion and constriction are important causes of simple bowel obstruction as well as strangulated obstruction.