HYPOTHESIS ON THE PATHOPHYSIOLOGY OF SMALL INTESTINAL STRANGULATION BY PEDUNCULATED LIPOMAS

Background: To explain the pathogenesis of pedunculated lipoma strangulation, many authors stated that it moves around a loop of intestine wrapping it with its stalk. Why the lipoma should move around the loops of intestine and why it then became entangled is not explained, making this hypothesis not fully convincing. Objectives: To propose an explanation of strangulation by pedunculated lipomas that accounts for the many aspects this pathology involves. Methods: Analysis of the anatomical features of 11 cases of lipoma strangulation in horses. Results: We hypothesised that the stalk is tensioned by the weight of the lipoma or by the fact that the lipoma is trapped between portions of intestine. This produces a slit-like aperture formed by the stalk and the mesentery. One (or multiple) loop of intestine pass lateral to the stalk before turning into this aperture either because of lack of space in the abdominal cavity or by effects of the peristalsis. The weight of the intestine itself causes a ‘fall’ of the loop. This causes a modification of the whole system similar to that done by a surgeon when making a half-hitch knot: the falling of the loop cause a movement of the ‘post’ formed by the stalk of the lipoma that turns in a half-hitch that strangulates the loop of intestine. Conclusions: This hypothesis, as opposed to previously proposed ones, can explain strangulation by short and long stalk pedunculated lipomas, by lipomas of different weights and shape and of multiple loops of bowel simultaneously.