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.
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 1: A mare's uterus after the broad ligament has been elevated.
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.
Photo 2: A mare's uterus six months after surgery.
"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.
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.