Horse bellybuttons can serve a critical surgical role, literally as a portal between the animal’s inside and out. That’s exactly how researchers in California have been using them recently, specifically for getting retained testicles out of the body with minimal complications.

“We think closure is more secure along that midline, maybe because it’s a thicker area to close, and it’s a cleaner technique than bringing (the testicle) out through the parainguinal region (closer to the scrotum),” said Andrew T. Fischer, DVM, Dipl. ACVS, at Chino Valley Equine Hospital, Chino Hills, California.

Male horses with testicles nestled within the abdomen, anywhere from just above the scrotum—where they should be—all the way up to near the kidneys, are known as cryptorchids. Over the past 30 years, many veterinarians have inserted instruments through keyhole incisions in the lower abdomen—a technique known as laparoscopy—to find and clip the testicle free and cauterize or ligate the blood supply and other attached structures.

But the newly loosened testicle is wider than the surgical instruments—which also include a small camera and a cannula that pumps carbon dioxide into the abdomen for better viewing—so it can’t fit through those keyhole incisions. Surgeons generally widen the incision closest to the testicle, in the inguinal region near the scrotum, to get the testicle out. While that technique is usually successful, it comes with a risk of significant hemorrhage because the area has many major blood vessels, including the superficial epigastric artery. Accidental cutting of that artery has caused some horses to bleed to death during or after surgery, Fischer said.

So for the past 15 years, Fischer has been trying a different approach: passing the testicle through the umbilical portal—a hole in the horse’s belly button. With the horse under general anesthesia lying on his back, Fischer inserts instruments through tiny incisions in the inguinal area to inflate the abdomen and find the testicle. After clipping the testicle free, he then uses forceps to pass it to a second set of forceps that comes int o the abdomen through the umbilical portal. Grabbing the testicle with that second set of forceps, he pulls it out through the larger opening without having to cut the tiny inguinal incisions larger than they already are for the instruments.

“What I really like is that you end up with two 5-millimeter incisions for your … devices and then maybe a 2- or 3-centimeter incision through the umbilicus (for tissue removal), when it’s all said and done,” Fischer told The Horse.

Between 2006 and 2016, Fischer performed 90 cryptorchidectomies on 79 horses using this laparoscopic approach with testicle removal through the umbilical portal. Complications were mild and rare (except for one horse that had to be euthanized during recovery due to neurologic issues likely related to anesthesia), he said. Cauterizing the blood vessels leading to the testicle appeared to limit the chances the stump would bleed.

“Laparoscopic procedures are good for horses—and their owners—because we (surgeons) can always see when there’s bleeding, so we can try to correct that right away,” he said. “So that means fewer issues with post-op hemorrhage.”

Incidentally, Fischer also noted a much lower colic rate after his team’s cryptorchidectomies compared to other cryptorchidectomy laparoscopies. He suspected that might be related to a shorter preoperative fasting period, rather than the use of the umbilical portal. He only withholds food from patients for 12 to 18 hours (as opposed to up to 48) pre-surgery, which could contribute to less digestive discomfort, he said. In addition, his team deflates the abdomen from the pumped-in carbon dioxide as much as possible before stitching the horse back up. That could release pressure on the digestive system, they stated in their peer-reviewed paper.

The paper, “Removal of equine cryptorchid testes through an enlarged umbilical portal in dorsally recumbent horses after intra-abdominal laparoscopic castration,” was published by Equine Veterinary Journal on June 10, 2021.