34th Annual Scientific Meeting proceedings

Objectives:

The ventral and dorsal components of the ascending colon are adjoined by the ascending mesocolon, and few case reports have described congenital or acquired malformations of this structure.The objective was to report the occurrence of large mesenteric rents of the ascending mesocolon with concurrent colon displacements in 6 adult horses.

Methods:

Retrospective case series.

Results:

The included cases underwent a median laparotomy because of colic signs refractory to medical treatment. A large full thickness rent was found in the ascending mesocolon, and the rent appeared subacute or chronic with rounded edges in 5/6 cases. Most defects were located directly adjacent to the left dorsal colon, and the maximum diameter varied between 20 and 80 cm. Two different types of intestinal displacements in relation to the rent were found, with either a localized torsion of the adjacent dorsal colon, or herniation of the pelvic flexure through the rent. In all cases, the intestine could be repositioned, and the rent was sutured. None of the cases necessitated colonic resection. Despite some minor postoperative complications, the short- and long-term outcomes were excellent. Based on the history of the patients, the rents were most likely acquired, although histology was not performed to further characterize the margins.

Conclusions:

Large rents of the ascending mesocolon can facilitate atypical colonic displacements, but did not result in ischaemic injury. The aetiology of the rents cannot by elucidated by this retrospective analysis, but some defects may have been caused by previous colon displacements or trauma elicited by the intrauterine foal.