Surgical Removal of Urinary Bladder Urolith in Female Asian Elephant (Elephas maximus) by Episiotomy and Urinary Bladder Sphincterotomy

Abstract

A 50-year-old female Asian elephant (Elephas maximus) was referred to the Kasetsart University Veterinary Teaching Hospital with histories of anuria and abdominal pain for five days. Trans-rectal ultrasonography demonstrated the presence of hyperechogenic uroliths located between the neck and trigone of the urinary bladder. Vestibuloscopy by endoscope revealed an abnormal brownish mass obstructing the internal bladder orifice. Episiotomy was performed after standing sedation with dexmedetomidine, epidural anesthesia and perineal infiltration with lidocaine. A single 1.7 kg urinary bladder urolith with 17x12x10 cm dimension was manually removed using a combination of several methods, including sphincter dilatation using lidocaine ring infiltration at the sphincter, blind sphincterotomy, rope woven basket and intraluminal inflation with gas. The episiotomy site was left open as a window for further wound cleaning and urinary bladder lavage. Signs of chronic kidney disease were detected and post-operative care was started. However, this elephant died on day 80 after the surgery. A necropsy was performed and the major finding was severe diffuse necrosis of both kidneys. Calcium carbonate was identified as the urolith’s main component. Predisposing factors for urolith formation in this case remains unclear.