Risk Factors for Colic Surgery Incision Failure Studied
While colic surgery is a life-saving procedure for many horses, it’s not without its risks. One rare, but potentially catastrophic, complication that occurs in 1% of colic surgery patients is abdominal incision dehiscence and visceral prolapse—when the incision the surgeon made to access the abdomen reopens, allowing the intestines to drop out of the abdomen.

In the best-case scenario, the surgeon can clean up and resuture the incision without additional complications. In the worst-case scenario, too much damage occurs and the horse must be euthanized.

While veterinarians monitor all patients for signs of incision failure, it hasn’t been clear which, if any, cases are at greater risk for complications or what factors influence survival following incision failure. So, Alison Gardner, DVM, MS, Dipl. ACVS-LA, an assistant professor at The Ohio State University (OSU) College of Veterinary Medicine Department of Veterinary Clinical Sciences, in Columbus, recently completed a study on the topic. She shared the results at the 2017 International Equine Colic Research Symposium, held July 18-20, in Lexington, Kentucky.

Gardner and colleague Margaret Mudge, VMD, Dipl. ACVS, ACVECC, a clinical associate professor at the OSU College of Veterinary Medicine, reviewed 10 years of medical records to identify risk factors for acute ventral midline dehiscence and evaluate survival after wire placement to re-close the incision.

The team included 10 cases with acute dehiscence and visceral protrusion in their evaluation, half of which were draft horses. Horses’ weights ranged from 227 to 900 kilograms (about 500 to 1,984 pounds), with an average of 540 kilograms (about 1,200 pounds).

Key findings included:

  • Incision dehiscence, a risk factor researchers identified previously, occurred, on average, eight days after surgery;
  • Seven horses had signs of incisional infection prior to dehiscence, two of which survived;
  • Eight horses dehisced while still at the clinic; the two horses that dehisced following discharge did not survive;
  • Four of the 10 cases dehisced after a second colic surgery, another previously described risk factor;
  • Two horses developed hemoabdomen (blood accumulation in the abdomen) following difficult recoveries;
  • All cases had abdominal wall failure with the suture line remaining intact, meaning the abdominal wall itself tore, rather than the sutures reopening; and
  • Surgeons re-closed the abdominal wall in three horses using 18-gauge wires; two of the three survived.

Gardner and Mudge concluded that draft breeds and horses with incisional infections could be more likely to suffer body wall failure and incisional dehiscence. Gardner cautioned that researchers still have to evaluate these factors statistically against case controls. Further, they determined that horses are more likely to survive if incisional failure is identified promptly and treatment is rendered immediately.

While the team garnered important information on body wall failure and incisional dehiscence, Gardner stressed that this complication is rare, occuring in even less than 1% of the colic cases the OSU treats.

“I don’t want owners to decline surgery because they’re worried about this complication,” she said. “The purpose of the case series was to correlate clinical signs that these horses may have prior to dehiscence. Ongoing work with cases from other hospitals is occurring along with case controls for statistical analysis of risk factors.”