BRIEF COMMUNICATION

Inguinal Herniation of the Ascending Colon in a 6-month-old

Standardbred Colt

EMILY ROBINSON, BSc, DVM and JAMES L. CARMALT, MA, VetMB, MVetSc, Diplomate ABVP & ACVS

Objective—To report inguinal herniation of the ascending colon in a Standardbred colt.Study Design—Case report.Animals—A 6-month-old Standardbred colt.Methods—The colt underwent surgical exploration of the hernia with large colon resection andanastomosis.Results—A successful large colon resection and anastomosis was completed, however, the colt waseuthanatized at the end of surgery upon owner request.Conclusions and Clinical Relevance—Although uncommon, indirect inguinal herniation of theascending colon can occur in young horses.r Copyright 2009 by The American College of Veterinary Surgeons

We report inguinal herniation (3 days duration) ofthe ascending colon in a 6-month-old Standard-

bred colt. Forty-eight hours before admission, the ownershad observed swelling in the scrotal region but there wereno signs of discomfort. Immediately before admissionsigns of acute colic occurred, inguinal herniation was di-agnosed, and the foal referred for surgery. On admissionthe colt had signs of colic, multiple facial lacerations, andprominent scrotal swelling on the left side that was pain-ful on palpation. There was complete absence ofborborygmi, tachycardia (86 beats/min), pink mucousmembranes with a mild toxic line evident at the gingivalmargins of the incisor teeth, and capillary refill time of2–3 seconds. Hematocrit was 46% and serum total proteinconcentration, 7 g/L. Xylazine hydrochloride (0.5mg/kgintravenously [IV]) and butorphanol tartrate (0.025mg/kg IV) were administered to facilitate examination andwithin 15 minutes, signs of severe abdominal pain requiredfurther administration of xylazine hydrochloride (0.75mg/

kg IV) and butorphanol tartrate (0.025mg/kg IV). Thick-ened intestine, suggestive of ascending colon, with reducedmotility was identified on ultrasonography of the scrotalmass.

The foal was anesthetized, positioned in dorsal re-cumbency, and a 15 cm incision over the scrotal massexposed the pelvic flexure and most of the most of theascending colon herniated through the left inguinal canal.The abdominal musculature adjacent the inguinal ringwas intact; however, the vaginal tunic was not evident.The colon was dark pink with serosal petechiation.Despite enlarging the inguinal ring by incising ( � 6 cm)the external inguinal ring (and vaginal ring) in a lateraldirection along its long axis into the abdomen, the her-niated colon could not be reduced, so a 25 cm ventralmedian incision was made to facilitate reduction. Theascending colon was identified at the cecocolic ligamentand using intra-abdominal traction and external pulsion,the hernia was reduced and colonic viability assessed. The

Corresponding author: Dr. James Carmalt, MA, VetMB, MVetSc, Diplomate ABVP & ACVS, Western College of Veterinary

Medicine – Large Animal Clinical Sciences, 52 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N5B4.

E-mail: carmalt_vet@hotmail.com

Submitted May 2009; Accepted July 2009

From the Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan,

Saskatoon, Canada

r Copyright 2009 by The American College of Veterinary Surgeons0161-3499/09doi:10.1111/j.1532-950X.2009.00595.x

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Veterinary Surgery

38:1012–1013, 2009

colonic wall was dark pink and edematous �10 cm distalto the cecocolic ligament. Colonic blood supply appearedcompromised (weak pulse in the right colic artery) andmotility was absent. The left testicle was located betweenthe colon and the abdominal wall in the inguinal region.It was flaccid, had evidence of petechiation and did notappear to be viable. The owner could not be contacted socolonic resection and end-to-end anastomosis was per-formed. Unfortunately, after anastomosis but before re-covery from anesthesia, the owner requested euthanasiaof the colt.

Acquired inguinal hernia occurs most commonly installions, but has been reported in foals, and very rarelyin geldings or mares.1 A higher incidence of inguinalhernias in Standardbreds and European Warmbloods1,2

may be associated with the size and shape of the vaginalring.2 Causes of inguinal herniation include abdominaltrauma, breeding accidents, strenuous exercise, and as acomplication of castration.3 As occurred in this colt, mostacquired inguinal hernias in horses are indirect with theherniated contents (most commonly jejunum or ileum)passing through the inguinal canal and becoming stran-gulated by either the vaginal or external inguinal ring.4

A Richter’s hernia, where one wall of the ascending colonwas involved in an inguinal hernia and subsequentlyruptured, has been reported.5

Surgical correction of inguinal herniation involves re-duction of the herniated content possibly with intestinalresection and anastomosis depending on intestinal via-bility. Whereas it is possible to perform some intestinalresections (depending on the anatomic region) and anas-tomosis before hernia reduction, most surgeons prefer toassess intestinal viability and if needed, perform resectionand anastomosis via median celiotomy.4 As in this foal,reduction is often facilitated by a combination of tractionand external pulsion and this approach may limit further

enlargement of the vaginal ring. Enlarging the vaginalring by incision may be necessary to facilitate reduc-tion.1,4 Castration is often required because of testicularinjury and vascular compromise, and may facilitate re-duction.4 Castration on the affected side allows completeclosure of the vaginal tunic, decreasing the risk of recur-rence.1 It may not completely eliminate the recurrence ofherniation as a direct hernia of abdominal contents viathe abdominal musculature may occur adjacent to theexternal inguinal ring. Although laparoscopic her-niorrhaphy techniques have been reported in horses,2,6

the size of the herniated viscera, degree of edema and thenecessity of a resection and anastomosis would have pre-cluded correction by this approach.

This report demonstrates that while uncommon, asubstantial amount of ascending colon can exit the ab-domen via an indirect inguinal hernia in young horses.

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