A NOVEL TECHNIQUE OF URETERONEOCYSTOSTOMY (EXTRAVESICAL SEROMUSCULAR TUNNEL) - AN EXPERIMENTAL-STUDY IN DOGS .2. OPTIMIZATION OF SURGICAL TECHNIQUE

Objectives. To optimize the surgical technique of the new extravesical seromuscular tunnel ureteroneocystostomy and to study the optimal rel ation between the length and width of the tunnel and the diameter of t he normal and dilated ureters. Methods. The optimized technique was ap plied to the left ureters of 20 dogs; 10 with normal ureters and 10 af ter induction of ureteral dilation. The new technique was performed to maintain a ratio of 3: 1 between the width of the tunnel and the diam eter of the ureter and a ratio of 1:1 between the length of the tunnel and the ureteral diameter. The results were compared with those for 5 dogs in which unilateral direct ureterovesical reimplantation was per formed without an antireflux procedure. All the dogs were evaluated by intravenous urography, radioisotope renography, and ascending cystogr aphy before and at 1, 5, and 6 months after ureteroneocystostomy. Resu lts. All the dogs of the control group showed low-pressure vesicourete ral reflux and 3 demonstrated mild hydronephrosis and significant dete rioration of the corresponding kidney. At 6-month follow-up, none of t he 20 dogs subjected to the new technique showed deterioration of the function or configuration of the corresponding kidney. Moreover, the n ew technique was sufficient to prevent reflux in all but two dilated u reters that showed high-pressure vesicoureteral reflux. Conclusions. F or the extravesical seromuscular tunnel to be effective in reflux prev ention without obstruction, the width of the tunnel must be triple the diameter of the ureter, and the length of the tunnel covering the int act (nonspatulated) part of the ureter should be equal to its diameter . Copyright 1996 by Elsevier Science Inc.