Uteropexy: A new technique to improve the fertility of barren mares - DVM
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Uteropexy: A new technique to improve the fertility of barren mares


DVM360 MAGAZINE


A new treatment: Uteropexy

Previously, no effective treatment had been established for these mares. Practitioners have generally tried to keep the mares as clean as they can, used uterine lavages and hormonal drugs to try to keep their uterine tone and attempted to keep them clean enough to get bred. Many of the mares, even though they have heavy, pendulous uteri, can be sufficiently cleaned up to get bred. "It takes a fair amount of veterinary intervention to get the mares in foal and to keep them in foal," says Johnson.

A new surgical intervention, uteropexy surgery, was developed by Schumacher and Brink to physically translocate the uterus from a pendulous, ventral position up to a more normal position. "I was visiting with a colleague in theriogenology about the broad ligament, and he was telling me how important he thought it was for normal uterine conformation," says Schumacher. "It came to me, that in mares with greatly lengthened broad ligaments and poor uterine conformation, we could shorten the ligament, and get better uterine conformation."

Schumacher thought these mares might benefit from elevation of the uterus to a more normal, horizontal position so that they regain normal tone and function of the uterus musculature to evacuate contents of the uterus. This procedure is a logical way to try to get these mares to clean up and get them back in foal. "Whether it will prove to be efficacious under scientific testing remains to be seen, but some of the mares we've treated have done quite well," Schumacher says.


Photo 1: A mare's uterus after the broad ligament has been elevated.
The uteropexy procedure is a laparoscopic technique performed with the mare standing and sedated but not anesthetized. The uterus is suspended from the dorsal abdominal cavity by the broad ligament of the uterus, the mesometrium. The laparoscope is placed into the mare's flank bilaterally, starting near the body of the uterus. Suturing starts right at the bifurcation, basically plicating and, thus, shortening the broad ligament. A suture is placed where the broad ligament goes into the uterus, and then, as dorsally as possible, a bite is taken into the broad ligament. When the suture is tied together, it plicates, shortening the distance. This suturing is done in a continuous line, ending just before the oviduct enters into the uterus.


Photo 2: A mare's uterus six months after surgery.
About two inches of the cranial aspect of the uterus is left untouched to ensure the plumbing from the ovary to the uterus is not damaged. Essentially the uterus is sutured so it sits higher than it was before, allowing fluids to flow downhill. Once the left side is completed, the procedure is repeated on the right (Photos 1 and 2). It's just a simple continuous pattern between the dorsal aspect of the broad ligament and the ventral aspect of the broad ligament, where it inserts onto the uterus. "But it's not easy," says Johnson.

"It took awhile to get the procedure to its current state and required the help of a colleague, Brink, expertly skilled at laparoscopic surgical procedures to help devise the technique for imbricating the broad ligament," says Schumacher. "He developed the technique using a needle holder, but because we are not as skilled at laparoscopic surgery as Brink is, we use a laparoscopic instrument that simplifies the procedure for us."

The results thus far

Uteropexy is a fairly new technique and, at this point, has been done on a limited number of mares. Brink has performed more of the procedures than any of the other investigators. For the 2008 breeding season, he shortened the broad ligament of five barren mares. Three of those mares were rebred, and all delivered foals. One of these mares was subsequently rebred and conceived. Brink operated on another four mares in 2009. Johnson has treated five mares this breeding season in Lexington. Schumacher has performed the procedure on four horses in Lexington, one horse in Tennessee and one horse in California, and he will perform one next month in Ireland. He has also performed the procedure twice with Brink in Sweden. A former colleague of Schumacher has done a few uteropexies in Australia.

"We are in the beginning stages of knowing how efficacious the uteropexy procedure is going to be," says Johnson. "It certainly does improve the perineal conformation immediately. So that's a very positive thing. I don't know if that means that we're going to buy these mares at least one more breeding season or not. To tell you the truth, that remains to be seen because a lot of the mares in my practice that the procedure was performed on have been barren for several years, and this was a last-ditch effort for these mares." Johnson says that they were generally well-bred mares with a proven record that they couldn't get in foal anymore, so there was some value.

At Woodford, they did not do exhaustive diagnostics on the mares that underwent the procedure. "That's a variable that I wish we could have avoided, but it was not going to be financially possible to do all these tests," Johnson says. "We talked about whether we might give the surgery a bad name by going this route, but that was the only route we were going to be able to try. To get this done on mares, there would be no way to test this in vitro. We were going to have to test it in vivo."

"Brink has gone back and laparoscopically evaluated three mares and noted that their uteruses were suspended in a horizontal position by a sheath of scar tissue," says Schumacher. "The sheath of scar tissue doesn't seem to interfere too much with palpation. As far as complications go, there really haven't been any. However, there has been some difficulty in performing the procedure. But as we do more and more, we're getting better and better at it."

Ed Kane, PhD, is a researcher and consultant in animal nutrition. He is an author and editor on nutrition, physiology and veterinary medicine with a background in horses, pets and livestock. He is based in Seattle.

REFERENCES

1. Hughes JP, Loy RG. Investigations on the effect on intrauterine inoculation of Streptococcus zooepidemicus in the mare, in Proceedings. Am Assoc Eq Pract, 1969;289-292.

2. Adams GP, Kastelic JP, Bergfelt DR, et al. Effect of uterine inflammation and ultrasonically-detected uterine pathology on fertility in the mare. J Reprod Fert Suppl 1987;35:445-454.

3. LeBlanc MM, Neuwirth L, Jones L, et al. Differences in uterine position of reproductively normal mares and those with delayed uterine clearance detected by scintigraphy. Theriogenology 1998;50(1):49-54.

4. Zent WW, Troedsson MHT, Xue JL. Postbreeding uterine fluid accumulation in a normal population of Thoroughbred mares: a field study, in Proceedings. Am Assoc Eq Pract, 1998;64-65.


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