Progressive urethral dilation in male horses undergoing perineal urethrotomy for cystolith removal: 22 cases

This retrospective case series describes the use of progressive urethral dilation in 22 client-owned male horses undergoing perineal urethrotomy (PU) for cystolith removal. Medical records of horses undergoing PU and urethral dilation for treatment of cystolithiasis were reviewed. Dilation of the pelvic urethra was performed following PU and using customized dilators with the same length (30cm) and with various outer diameters (25 to 45mm). Analyzed data included: signalment, cystolith size, renal ultrasound findings, method used for cystolith removal, diameter of urethral dilators, intra- and post-operative complications, and hospitalization time. Cystolith size ranged between 37mm and 90mm. Dilation of the pelvic urethra was as follows: 35mm (n=8), 25mm (n=6), 39mm (n=3), 33mm (n=2), 28mm (n=2) and 45mm (n=1). In 6 cases, the cystolith was removed without fragmentation. In the remaining 16 horses, lithotripsy was performed with forceps (n=9) or a pneumatic scaler (n=7). In 15 horses a retrieval device was used to aid in calculi removal. Hospitalization time ranged between 1 and 5 days. Intra-operative complications occurred in one horse. No post-operative complications were recorded. Follow-up information was available for 21 horses (range 1-8 years). Urethral dilation via PU may be a viable option for cystolith removal in male horses.