Ureteronephrectomy is the most commonly performed surgical procedure of the kidney. It is indicated when one of the kidneys is detrimental to the animal's health whilst the function of the contralateral one is adequate to sustain life. This frequently occurs in cases of advanced hydronephrosis – usually secondary to obstruction of the ureter or the renal pelvis. Whenever possible the kidney is spared, and alternative procedures are performed to resolve the obstruction. Nephrotomy and pyelotomy are rarely performed, and recently have been associated with or superseded by ureteral stenting. All the latter procedures are technically challenging, and require advanced expertise and facilities.