When a high-quality Quarter Horse broodmare who had produced several very good horses was sold privately in the upper Midwest, the buyers thought they had a great bargain. And their initial goal was to use the broodmare as the donor for embryo transplants, which are allowed with Quarter Horses.
Then, they brought her home and found she had a “large recto-vaginal fistula bigger than the size of a quarter,” said Rif’at Hussain, MD, who was asked by the mare’s vet to consult on the mare’s problem. The fistula was allowing manure to get into the mare’s vagina, with the resultant bacterial contamination making it essentially impossible for her to conceive and remain pregnant.
The initial cause of the problem had been a dystocia, or difficult birth, with the foal’s foot puncturing the wall of the birth canal and then the rectal lining that lies above, as well.
The previous owner’s attending veterinarian at the time at the time of the injury had tried to sew up the tear immediately, but the repaired wound fell apart, resulting in a large opening between the rectum and the vaginal cavity.
The new owners sent the mare to their local veterinary surgeon, who operated on the mare four times, but the repaired wound not hold up and broke down, resulting in the recto-vaginal fistula remaining open. The vet called Dr. Hussain, who is in practice of plastic and reconstructive surgery for human beings and has decades of experience working with soft-tissue injuries.
He said, “Without experience dealing with soft tissue reconstruction, this problem would be very difficult to resolve. First, you have to keep in mind that your incisions will not interfere with or interrupt the blood supply of the tissues involved. And second, in carrying out reconstruction of soft tissues, the repair cannot be under any tension, or the repair will fall apart returning the situation to where you started from.”
When Dr. Hussain heard about this mare’s problem, he knew that his experience with soft-tissue reconstructive surgery should help him in solving this problem and hoping for a positive result.
Then he went to the vet’s clinic. The drive was 125 miles each way, approximately an hour and a half at the doc’s usual rate of travel.
“I had not seen nor examined the problem of the mare before,” he said, “and when I saw the magnitude of the problem, I realized that I had to come up with a procedure not described in the equine surgical literature. The procedures that are normally used to repair recto-vaginal fistulas of this sort in broodmares would not work because of the scarring from previous surgeries. The four operations that were done consisted of making the fistula into a complete perineal tear and then carrying out the actual repair. The scarring resulting from those previous surgeries dictated I had to think of something different for the problem.”
Dr. Hussain did the surgery on the mare while she was standing up, after she had been placed in a heavy metal device called stocks or stanchions. He was assisted by the veterinarian. For anesthesia, they used general sedation and an epidural block done by the vet.
Leaving the mare standing was intentional because it “gives better perception of the effects of gravity on the repaired wound,” and since it was the tension that had caused previous repairs to fail.
This case, which is in the process of being written up for a journal of veterinary surgery, pushed Dr. Hussain to come up with a different approach than the standard operations that have been described in literature. A plastic surgeon who in his normal practice works on repairs of cleft lip and cleft palate and other reconstructive procedures in human beings used his 40-plus years of experience came up with an innovative idea for repair of a recto-vaginal fistula in mares.
For veterinarians trying to repair recto-vaginal fistulas in mares, Dr. Hussain had some brotherly advice on technical difficulties that they might face. He said, “First of all, the need for adequate lighting requires that a fiber-optic light source to illuminate a dark cavity, and second, professional surgical assistance is of paramount importance.
“I couldn’t do a damned thing about it because I was out in the middle of nowhere. So when I agreed to help with this case, I took my own fiber-optic lighted retractors, and I took my own instruments.
“And even then the procedure did take twice as long in my view. But you try to do things right, and proper assistance is frequently not available to veterinary surgeons, especially in clinic situations.
“Even so, with attention to detail and an obsession with fundamentals, this surgical technique will work anywhere. The one thing to keep in mind is to avoid tension. Of course, how you place the sutures and where the knots go make all the difference. You want to make sure that the rectal repair is done in a way that the actual sutures do not go through the rectal mucosa.
“All breakdowns of this type occur from breakdown of the rectal mucosal wound. That is where the manure is and thus all the possibility of infection. Likewise, you should keep in mind that the tissue of the birth canal will stretch.”
The result of this surgery done by a plastic surgeon on the Quarter Horse mare’s recto-vaginal fistula has had an excellent result so far. After six weeks, no breakdown has occurred, and it appears that she has healed well. Later this spring, the owners should be able to get her in foal and transfer the embryos to surrogates.