Study Supports Stent Use After Colic Surgery

Study Supports Stent Use After Colic Surgery

Researchers know that applying a stent bandage—basically a rolled-up sterile towel sutured to the incision site immediately after surgery—reduces the risk of incisional complications.

Photo: Aziz Tnibar, DVM, PhD, DECVS

More horses are surviving colic surgery than ever. But with that trend inevitably come more postoperative complications, including incisional infections. These infections are a significant cause of illness—not to mention expense—after colic surgery, so University of California, Davis, (UC Davis) researchers recently tested how well different stent bandages prevent them, namely one made with an antimicrobial-impregnated dressing.

“It’s been suggested that environmental contamination of the incision either during or following recovery from anesthesia can play a major role in development of surgical site infection,” said Isabelle Kilcoyne, MVB, Dipl. ACVS, an equine surgeon at the UC Davis School of Veterinary Medicine. She has assessed ways to reduce incisional infection risk in several studies and noted that risk factors range from having an incision longer than 27 centimeters to postoperative pain that causes horses to lie down more often. She presented results from the current study at the 12th International Equine Colic Research Symposium, held July 18-20 in Lexington, Kentucky.

KIlcoyne’s team had already determined that covering incisions with an abdominal bandage during anesthesia recovery helps prevent incisional infections. Further, they knew a stent bandage—basically a rolled-up sterile towel sutured to the incision site immediately after surgery—reduced the risk of incisional complications. But they hadn’t yet compared sterile towel stents to a simple adhesive drape cover and wanted to evaluate use of a stent bandage impregnated with 0.2% polyhexamethylene biguanide (PHMB).

“Polyhexamethylene biguanide has shown a pretty broad spectrum of action against both Gram-positive and Gram-negative bacteria,” she said. “It’s rapidly bactericidal at high concentrations and basically causes destruction of the bacterial cytoplasmic membrane, leading to precipitation of the cell contents.”

In other words, PHMB kills bacterial cells by draining them. Kilcoyne said manufacturer studies in humans and independent studies in small animals showed that PHMB-impregnated dressing reduced antibiotic-resistant bacteria within the bandage and colonization on the skin beneath it.

She and her research team compared the stents and the adhesive drape in a group of 75 horses undergoing ventral midline exploratory celiotomy—a fancy phrase for colic surgery. Surgeons used a standard abdominal closure protocol on all the horses included. Following closure of the abdominal incision they secured a sterile towel stent (24 horses) or a PHMB-impregnated stent (26 horses) over the incision using the same type of suture material and method, or they placed sterile gauze over the incision and covered it with a protective iodine-impregnated adhesive drape.

They considered incisional drainage continuing 24 hours after surgery an incisional infection. Eleven horses (14.7%) developed infections—none in the PHMB group, two in the sterile towel group, and nine in the adhesive drape group.

“The mean time to developing incisional drainage was 14 days,” she said, “and only two horses developed this at the hospital.” None of the horses that developed an incisional infection went on to develop a hernia.

“We believe that the use of the PHMB-impregnated dressing can help reduce the incidence of incisional infections,” Kilcoyne said. “Also, the use of any type of stent is beneficial to protect the incision.”

In closing, Kilcoyne emphasized the importance of follow-up with the referring veterinarian and communication with owners in identifying these cases because of the tendency for infections to develop after horses go home.

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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