Repair of a full thickness uterine tear via iatrogenic uterine prolapse in an anesthetized Thoroughbred broodmare

A 9 year old multiparous Thoroughbred mare at 347 days of pregnancy was presented to Rhinebeck Equine, LLP for a delay in progression of stage II parturition. Farm foaling attendant reported that the foal was not present in vaginal vault and instead 2 feet and a nose were present within rectum. Mare was transported to clinic immediately. On presentation, there was no evidence of a full thickness rectovaginal tear; however, the foal was displacing rectal mucosa dorsally. Mare was induced under general anesthesia and a live foal was delivered via controlled vaginal delivery. Following recovery of anesthesia, mare was assessed, based on farm history. There was no evidence of a rectovaginal fistula. Transabdominal ultrasonography revealed presence of swirling echogenic free fluid. Abdominocentesis was performed and hemorrhagic, nonclotting fluid obtained. Fluid analysis revealed elevated total nucleated cell count (7.55 x 103 /µl [reference range 1.5 - 5 x10 3 cells/µl]), elevated abdominal lactate (3.8 mmol/l [reference range 0 - 1.5 mmol/l]), and elevated total protein (2.6 g/dl [reference range < 2 g/dl]). Perineum was aseptically prepared. Digital manual transvaginal examination confirmed an ~ 15 - 20 cm full-thickness uterine tear on dorsal aspect of uterine body, to right of midline. Mare was induced under general anesthesia for uterine laceration correction. A ventral midline celiotomy was attempted, but due to caudodorsal location and size of the defect, surgical repair was not achieved. While in dorsal recumbency, uterus was manually prolapsed through vagina by placing gentle traction on attached fetal membranes. This approach allowed visualization and hand-sewn repair of laceration. The Dutch method (umbilical vessel water infusion) was used to facilitate removal of fetal membranes prior to uterus replacement. Recovery was uneventful. Rebreeding was delayed until the following season. Mare conceived on the second cycle and delivered a live normal colt at day 356 postovulation. To authors’ knowledge, iatrogenic uterine prolapse and umbilical vessel water infusion have not been reported. This technique is used by authors with good outcomes in mares with large, miduterine body laceration.

Keywords: Mare, dystocia, uterine tear

This manuscript was originally published in the journal Clinical Theriogenology Vol 12(3) Sept 2020.  Clinical Theriogenology is the official journal of the Society for Theriogenology (SFT) and the American College of Theriogenologists (ACT).  This content has been reproduced on the IVIS website with the explicit permission of the SFT/ACT.