Results of Laparoscopic Uteropexy (Imbrication of Mesometria) in Standing Horses

Introduction
Normally, mares are resistant to uterine infection after breeding, even though the endometrium is subjected to the inflammatory effects of debris and bacteria deposited into the uterus during copulation. Mares unable to clear the deposited debris and bacteria from the uterus are susceptible to uterine infection. Susceptible mares often have a uterus that is oriented vertically within the abdominal cavity rather than in a normal, horizontal position. This detrimental change in uterine position results from stretching of the mesometrium from the weight of foals during numerous pregnancies. Contractions of a horizontally oriented uterus successfully propel the contaminated uterine fluid and debris caudally causing it to exit the uterus, but the strength of contractions of a ventrally oriented uterus may be inadequate to clear the uterus of debris and bacteria that incite inflammation. A ventrally oriented uterus can be returned to a normal, horizontal orientation by imbricating the two mesometria that suspend the uterine body and each horn. By returning the uterus to its normal, horizontal position, uterine clearance may improve, which in turn, may improve fertility, provided significant, irreversible disease of the endometrium has not occurred.

Surgical technique
The surgery to re-suspend the uterus in a horizontal orientation (i.e., uteropexy) has been described in detail elsewhere (Brink et al., 2012), but a brief description of the laparoscopic surgery follows. Uteropexy can usually be performed without insufflating the abdomen if the mare is held off-feed for at least 36 hours. Pre-surgical treatment with an analgesic agent, such as flunixin meglumine, may prevent post-operative abdominal discomfort. The mare is sedated with detomidine hydrochloride (0.005-0.01 mg/kg, IV) and butorphanol tartrate (0.01-0.02 mg/kg, IV) administered as a bolus. Administration of these drugs can be repeated if necessary, or sedation can be maintained at a more constant level by using continuous rate infusion after administering a loading bolus of the sedative detomidine (0.02 mg/kg/hour) and butorphanol (0.012 mg/kg/hour).  [...]