Study Evaluates Surgical Strangulation Colic Survival Rates

Study Evaluates Surgical Strangulation Colic Survival Rates

All horses managed without resection survived to be discharged from the hospital after surgery, and only three suffered serious post-surgical complications, but all responded to treatment.

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Colic surgery carries many unknowns: Does my horse really need it? How much is it going to cost? And, most importantly, will my horse survive? Researchers from the University of Florida are seeking to answer some of these questions, at least in regard to small intestine resection—a complicated procedure performed on horses suffering from strangulation colic. They recently developed and tested a grading scale designed to help veterinarians determine whether affected horses need this resection and found that, in some cases, they don’t.

Researcher David Freeman, MVB, PhD, Dipl. ACVS, chief of large animal surgery at the University of Florida College of Veterinary Medicine, and colleagues explained in the study that one of the most serious types of colic is small intestine strangulation, which develops from a twist or entrapment of the gut. Such strangulations can interrupt blood flow to a segment of intestine, damaging or possibly killing part of it and necessitating complicated surgical correction.

During surgery veterinarians sometimes have difficulty judging whether the intestine will recover after strangulation if it's damaged rather than dead. One of the most difficult decisions a surgeon must make is whether to remove (or resect) strangulated intestine and reattach the remaining functional ends (or anastomosis, joining the resected bowel back together); alternatively, the small intestine can be left in place to recover on its own. Most surgeons will perform a resection and anastomosis if they doubt the intestine's healing potential, Freeman said. However, problems lie in the fact that unnecessary resection adds to the already expensive surgical costs and can put the horse at risk for developing complications.

To that end, Freeman and colleagues set out to develop a grading system veterinarians can use to determine if the intestinal segment of concern is still capable of normal function. The team based their 5-point scale (with 1 being least severe and 5 being most severe) on the intestine's potential ability to regain blood flow and return to a healthy color and appearance after correction of lesions.

The research team examined the short- and long-term recovery rates of 35 horses that underwent surgery for small intestinal strangulation without resection between 1996 and 2011. Additionally, they obtained long-term postoperative follow-up information (ranging from 20 months after surgery to nearly 200) on as many horses as they could.

Some of the researchers' key findings included:

  • All horses survived to be discharged from the hospital after surgery;
  • Three horses (9%) suffered serious post-surgical complications, but all responded to treatment;
  • Ten of the horses died at some point after discharge, mostly from old age or causes unrelated to the surgery. Still, statistical evaluations showed that half the horses in the study were alive at 120 months or longer, which Freeman said could be the longest such time recorded after small intestine strangulation surgery; and
  • Horses with small intestines rated between a Grade 1 and a Grade 3 do not necessarily need to be resected; some but not all Grade 4 segments might need resection.

“I would hope that this study would help surgeons to more accurately predict what strangulated segments of intestine will survive without complications if left in the horse,” said Freeman. “If the correct decision is made, the surgery is completed quickly, the horse is subjected to a simpler procedure, the owner is spared the cost of a long and difficult surgery, and the complication rate is low. More importantly, long-term survival is good.”

Freeman said these study results strongly suggest that horses referred to a clinic shortly after developing signs of colic would have a better chance of avoiding a complicated and costly resection and also have an excellent chance of survival.

The study, "Long-term survival in horses with strangulating obstruction of the small intestine managed without resection," will appear in the Equine Veterinary Journal

About the Author

Natalie Voss

Natalie Voss is a freelance writer and editor based in Kentucky. She received her bachelor's degree in equine science from the University of Kentucky and has worked in public relations for equine businesses and organizations. She spends her spare time riding her Draft cross, Jitterbug.

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