Mesenteric rents as a source of small intestinal strangulation in horses: 15 cases (1990-1997).

OBJECTIVE: To describe the clinical findings in horses with small intestinal strangulation through mesenteric rents, and to determine the recurrence and survival rates after surgery. DESIGN: Retrospective study. ANIMALS: 15 horses with small intestinal obstruction via a mesenteric rent. PROCEDURE: Medical records of horses with obstruction of the small intestine via a mesenteric rent between January 1990 and December 1997 were reviewed. The signalment, history, initial physical examination findings, results of abdominocentesis, and clinical laboratory values were recorded. Surgical findings, including location of the mesenteric rent and surgical procedure performed, were recorded. Short- and long-term survival rates were calculated. RESULTS: Most mesenteric rents were located in the mesentery of the small intestine (13 horses). Two horses had multiple mesenteric defects. Seven horses were euthanatized at surgery because of an inability to reduce the entrapped intestine (3 horses), uncontrollable hemorrhage (2), inability to close the rent (1), and the amount of compromised intestine involved (1). Seven horses required intestinal resection and anastomosis. The median length of intestine resected was 2.6 m (range, 0.6 to 4.5 m). The mesenteric rents created during resection were not closed in 2 horses. One of these 2 horses subsequently developed a strangulating obstruction through the open rent. Seven of 15 horses in our study were discharged from the hospital (i.e., short-term survival rate of 47% [7/15]). Long-term follow-up information was available for 5 of the 7 horses (follow-up duration of 5 months to 9 years), of which 2 died as a result of colic, and 1 horse was euthanatized because of severe arthritis (i.e., long-term survival rate of 40% [2/5]). CONCLUSIONS AND CLINICAL RELEVANCE: Inability to reduce the intestinal obstruction, severe hemorrhage from the mesentery, and the length of intestine involved are the main factors that decrease survival rates in horses with small intestinal strangulation caused by mesenteric rents.