Evaluation of two nephrocystostomy techniques for ureteral bypass in cats

To describe two techniques for nephrocystostomy (NCT) in cats.

Experimental study.

Twelve, adult, purpose-bred, cats.

A simple NCT (n = 3) or bladder cuff NCT (n = 9) was performed in the right or left kidneys. For simple NCT, an 8F catheter was placed through the caudal pole into the renal pelvis and the bladder was sutured around the catheter. For bladder cuff NCT, a 6 mm defect was removed from the caudal pole and a cuff of bladder mucosa was advanced and sutured into the renal pelvis. A 10F catheter was placed through the defect into the renal pelvis and the bladder wall was sutured around the catheter. Catheters were removed 41-118 days post-surgery. Computed tomography (CT) was performed 25 days after catheter removal for the simple NCT and 30 (n = 6) and 90 (n = 3) days after catheter removal for bladder cuff NCT. Histological evaluation of the nephrocystostomy site was performed.

All simple NCTs became obstructed after catheter removal. All bladder cuff NCTs were patent, and CT revealed contrast flow into the bladder. Hematuria, clot-associated urethral obstruction, catheter dislodgement, and bladder infection occurred variably after surgery. Histological findings consisted of smooth epithelialization of the NCT and degenerative changes in the caudal pole of the kidney.

Bladder cuff NCT was feasible in normal cats and remained patent for 90 days. Methods to limit nephrostomy track hemorrhage should be investigated. Degenerative changes may be related to vascular impairment from the bladder cuff sutures.

Complete ureteral bypass was possible in cats using only native tissues.