Clinical features and outcome of 40 horses with mesodiverticular bands identified during exploratory laparotomy for management of acute colic

Alexander J Shanklin; Debra C Archer; Christopher M Baldwin

doi:10.1111/evj.14014

Clinical features and outcome of 40 horses with mesodiverticular bands identified during exploratory laparotomy for management of acute colic

Equine Vet J. 2023 Oct 3. doi: 10.1111/evj.14014. Online ahead of print.

Authors

Alexander J Shanklin¹, Debra C Archer¹, Christopher M Baldwin¹

Affiliation

¹ Department of Equine Clinical Science, Institute of Veterinary Science, University of Liverpool, Neston, UK.

PMID: 37787374
DOI: 10.1111/evj.14014

Abstract

Background: Mesodiverticular bands (MDBs) are an embryonic remnant of the vitelline artery. Information about the clinical significance of equine MDBs is currently limited.

Objectives: To report the clinical features, surgical findings and outcomes of horses undergoing exploratory laparotomy where a MDB was identified.

Study design: Retrospective case series.

Methods: Case records of horses undergoing exploratory laparotomy for colic over a 14-year period (2009-2022) were reviewed. MDBs identified at laparotomy were classified as the primary or contributory cause of abdominal pain, or as incidental.

Results: MDBs were identified in 40/1943 horses (2.1%) and 15 were primary (32.5%), 10 contributory (25%) and 15 incidental (32.5%). Horses with primary MDBs (median 2 years, IQR 1-12) were significantly younger than horses with incidental MDBs (median 8 years, IQR 6-16; P = 0.01). MDBs were more likely to be incidental if located in the mid-jejunum (5/5) (P < 0.001) or where a mesenteric pocket was absent (11/15) (P = 0.01). Primary MDBs caused extra-mural obstruction due to mesenteric shortening (n = 4), small intestinal entrapment within the MDB pocket (n = 5) or in an adjacent mesenteric rent (n = 4), and volvulus around the MDB (n = 2), with intestinal resection required in 8/15 cases. For horses with primary MDBs, survival to hospital discharge was 60% overall (9/15) and 75% for horses that stood following anaesthesia (9/12) with 88.9% of cases discharged from hospital (8/9) surviving >1 year. Excision of MDB tissue was not associated with complications but 3/4 non-incidental MDBs left in situ required relaparotomy to treat MDB-associated colic.

Main limitations: Retrospective single centre data.

Conclusions: Most MDBs in horses undergoing surgical treatment of colic in this population were not incidental. MDB-associated colic was most commonly classified as strangulating obstruction, but non-strangulating extra-mural compression was also identified. Excision of MDB tissue should be undertaken where possible, particularly in non-incidental cases.

Keywords: colic; congenital; horse; mesodiverticular band; small intestinal.