A new, unique and simple method for ureteral implantation in kidney recipients with small, defunctionalized bladders

Background Major, almost insurmountable, deterrents exist to the use of the small capacity, defunctionalized, nonneurogenic urinary bladder in renal t ransplantation, namely, the technical difficulty in performing a satisfacto ry ureteral implantation with conventional methods and the potential second ary problems with high grade ureteral reflux and obstruction. Alternatives are less than ideal and include transplantation into a bowel-augmented urin ary bladder with intermittent self-catheterization, ileal conduit urinary d iversion, or avoidance of transplantation and relegating the patient to lif e-long dialysis. Methods. Eight consecutive patients (ages 13 months to 29 years) with small , defunctionalized urinary bladders underwent a new method of intravesical implantation of the transplant ureter. The mean capacity of these bladders was 18.5+/-13.1 ml (range 6 to 45 mi), with the bladders defunctionalized f or a mean 81.6+/-24.3% of the patients' total lifetime. The technique invol ved placement of the transplant ureter into a shallow, mucosa-denuded, rect angular trough extending from a superiorly placed ureteral hiatus distally to the trigone. We hypothesized that the mucosal margins on the two lateral aspects of the rectangular trough would grow over the anterior surface of the meter until they met the advancing mucosal edges from the contralateral side to form a natural neosubmucosal tunnel. Results. Posttransplantation cystoscopic examination demonstrated bladder m ucosal regeneration and growth over the ureter, confirming the spontaneous development of a good length neosubmucosal tunnel. All patients demonstrate d no evidence of ureteral reflux or ureteral obstruction, whereas an immedi ate prior cohort of four consecutive patients with bladder capacities less than or equal to 30 mi showed that three of four had ureteral reflux (P=0.0 2) and four of four developed hydronephrosis (P=0.002). All urinary bladder s in the present cohort enlarged to expected normal or near-normal capaciti es. Serum creatinines were stable throughout the entire follow-up period, w ith the exception of one patient who had rejection episodes. Two patients h ad urinary tract infections posttransplantation, but there were no episodes of acute pyelonephritis. Conclusions. This novel technique for ureteral implantation successfully ca pitalizes on the regenerative potential of the bladder mucosa, resulting in a physiological, anatomically natural, and very effective neosubmucosal tu nnel. It appears to guarantee success against both ureteral reflux and obst ruction, no matter how small the urinary bladder, and offers no hindrance t o enlarging the bladder to near normal capacity posttransplantation. The im plantation technique is simple and safe, and its use should eliminate the r eluctance to use these bladders. Moreover, this procedure offers a major in centive for the successful rehabilitation of small, defunctionalized, nonne urogenic bladders after kidney transplantation.