Subcutaneous ureteral replacement: a canine model

There are several clinical situations in which extrinsic or intrinsic ureteral diseases necessitate extensive reconstructive surgery. Unfortunately, not all patients are candidates for such surgery (e.g., those with retroperitoneal metastatic disease). Ureteral replacement is indicated in this selected group of patients. A viable option is to establish a ureteral replacement using subcutaneous tubes. Among the problems associated with this method of urine diversion are selecting the proper material for the tubes, the timing of tube replacement, encrustation and occlusion, urine reflux, and renal function. There is an obvious need for an animal model to address these issues. The aim of this study was to establish a reproducible canine model for subcutaneous ureteral replacement, by using a combination of nephrostomy and cystostomy tubes joined together under the skin. The animal study was conducted in 6 dogs. A pigtail nephrostomy and a cystostomy were inserted through a midline abdominal incision and stab wounds in the abdominal wall. A subcutaneous tract was bluntly made toward the nephrostomy incision starting from the cystostomy incision. The nephrostomy was grasped with the clamp and brought through the subcutaneous tunnel to the cystostomy incision. Upon emerging through the cystostomy incision, the tubes were joined and buried under the skin. Intravenous urography at 4-6 weeks postoperatively in 4 dogs showed no deterioration of renal function, but some hydronephrosis was present. Using the technique described in this paper, it is possible to establish a subcutaneous ureteral replacement using nephrostomy and cystostomy tubes in dogs. This model may serve for further research of the various questions associated with subcutaneous ureteral replacement in humans.