References
Indications for and how to perform Caslick's operation in the mare
Abstract
The vulva functions as the most caudal of the three physical barriers between the uterine lumen and the outside world. A compromised vulval seal predisposes to pneumovagina (wind sucking) in mares and may lead to inflammation and ascending contamination of the caudal reproductive tract with pathogens, and/or urine pooling in the vagina. Abnormalities of a mare's perineal conformation and an inadequate vulval seal are most often corrected using Caslick's operation, a procedure that involves surgical apposition of the dorsal part of the vulval labia. The reasons for poor vulval conformation, and therefore the indications for a ‘Caslick's’, vary but can include advanced age, trauma induced by foaling, weight loss and, in some breeds, congenital predisposition. If Caslick's operation is insufficient to resolve the pneumovagina more invasive surgical procedures, such as vestibuloplasty or perineoplasty, should be considered.
The reproductive tract of the mare is protected against ascending contamination by three anatomical barriers. The most caudal and external of these barriers or seals is the vulva, followed by the vestibulovaginal fold and finally, the cervix. Together, these barriers significantly reduce the risk of air and debris entering the uterus (Inoue and Sekiguchi, 2017) and help minimise contamination of the reproductive tract by potential pathogens (McCue, 2008).
For an adequate vulval seal, a normal perineal conformation is necessary. A natural and good perineal conformation is achieved when the vulval labia are full and firm, and meet evenly at the midline (McCue, 2008; Papa et al, 2014; Inoue and Sekiguchi, 2017). Around 80% of the vulval opening should be located below the pelvic brim (Pascoe, 1979, 2007), and the vulval lips should be in a nearly vertical orientation (a deviation of <10°) (McCue, 2008) (Figure 1).
Register now to continue reading
Thank you for visiting UK-VET Equine and reading some of our peer-reviewed content for veterinary professionals. To continue reading this article, please register today.