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Updated: Jun 9, 2026
A Novel Surgical Technique in a Sheep Model for Suburethral Graft Implantation
Published on: June 20, 2025
Novel technique for correcting urovagina via urethral transposition in the horse
Robert McCarthy1, J Lacy Kamm1, Meredith Pierce2
1Carlson College of Veterinary Medicine at Oregon State University, Corvallis, Oregon, USA.
Background:
Vesicovaginal reflux is a common cause of infertility in mares. Surgical correction is commonly recommended and involves caudal relocation of the urethral orifice which forces the urine to be expelled caudally. There have been several previously described techniques. Complications associated with caudal urethral extension occur in 11-33.3% of cases.
Objective:
To identify a novel technique for performing caudal urethral translocation that effectively corrects vesicovaginal reflux with minimal associated complications.
Study Design:
In vivo experiment and clinical case series.
Methods:
The experimental study involved one normal horse. The procedure was then applied in three multiparous mares with urovagina that had been unable to conceive. Mares were sedated for a standing procedure and had a caudal epidural performed. The novel urethral translocation technique utilizing a sliding H flap with the removal of mucosa caudal to the urethral sphincter was performed. In the same procedure, a caudal relocation of the transverse fold was also performed. Mares were closely monitored for at least 1 month post-operatively. Clinical mares were followed for at least 1 year. The referring veterinarian and clients provided follow-up information.
Results:
The urethral transposition had no major complications in the experimental mare. In the clinically affected mares, the urethra was moved caudally by a mean of 4.17 cm (range 3.5-5.5 cm). Post-operatively, all clinically affected mares had no urovagina detected grossly on initial examination. Two of the three mares became pregnant on the second attempt post-surgery. One mare had intrauterine fluid visualised on ultrasound which improved with treatment for endometritis including bladder catheterisation and was able to become pregnant. This mare was presumptively diagnosed with post-operative urovagina. All mares foaled successfully post-surgery. All clients were satisfied with the procedure and outcome.
Main Limitations:
The main limitation of this study was the small sample size.
Conclusion:
This proposed novel technique provides an alternative method to treat urovagina. Further investigation to determine reproductive soundness post-operatively and to compare to previous methods is warranted.
