Multi-Institutional Retrospective Case-Control Study Evaluating Clinical Outcomes of Foals with Small Intestinal Strangulating Obstruction: 2000–2020

SIMPLE SUMMARY: Lower survival rates have been reported in foals than adults with severe colic lesions obstructing blood flow to the small intestine, but this has not been compared directly. These survival rates are important to horse owners making medical decisions surrounding colic, for both the foal’s wellbeing and the owner’s finances. In this retrospective case-control study, hospital records of surgical colic cases were collected from five US academic referral hospitals to directly compare foal and adult survival following surgery for specific colic lesions. It was hypothesized that foals would exhibit lower survival than case-matched adults. This study was limited by incomplete medical and surgical records, relatively small sample size, and lack of long-term follow-up. Short-term survival in foals was not significantly different than in adults with comparable colic lesions and may have been partly driven by decision-making on the farm prior to referral. More optimism toward surgical treatment of foals with suspected SISO may be warranted. ABSTRACT: Lower survival has been reported in foals than adults with small intestinal strangulating obstruction (SISO), but age-dependent outcomes have not been examined directly. Hospital records were collected from five US academic referral hospitals. It was hypothesized that foals would exhibit lower survival than case-matched adults. Foal cases 6-months-of-age or younger, and adult cases between 2- and 20-years-of-age were collected. Data revealed 24 of 25 (96.0%) foals and 66 of 75 (88.0%) adults that were recovered from surgery for SISO survived to hospital discharge. Sixteen of the total 41 (39.0%) foals studied were euthanized intraoperatively, whereas 30 of 105 (28.6%) adults were euthanized intraoperatively. Common lesions in foals that were recovered from surgery were volvulus (n = 13) and intussusception (n = 5), whereas common lesions in adults were volvulus (n = 25) and strangulating lipoma (n = 23). This study was limited by incomplete medical records, relatively small sample size, and lack of long-term follow-up. Unexpectedly, short-term survival tended to be higher in foals than adults and may have been partly driven by case selection prior to referral or surgery or decision-making intraoperatively. More optimism toward surgical treatment of foals with SISO may be warranted.