Reduced bladder capacity. Cause for vesicoureteral reflux

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 transplantation, namely, the technical difficulty in performing a satisfactory ureteral implantation with conventional methods and the potential secondary problems with high grade ureteral reflux and obstruction. Alternatives are less than ideal and include transplantation into a bowel-augmented urinary bladder with intermittent self-catheterization, ileal conduit urinary diversion, or avoidance of transplantation and relegating the patient to life-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 ml), with the bladders defunctionalized for a mean 81.6+/-24.3% of the patients' total lifetime. The technique involved placement of the transplant ureter into a shallow, mucosa-denuded, rectangular 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 ureter until they met the advancing mucosal edges from the contralateral side to form a natural neosubmucosal tunnel.

RESULTS

Posttransplantation cystoscopic examination demonstrated bladder mucosal regeneration and growth over the ureter, confirming the spontaneous development of a good length neosubmucosal tunnel. All patients demonstrated no evidence of ureteral reflux or ureteral obstruction, whereas an immediate prior cohort of four consecutive patients with bladder capacities < or =30 ml showed that three of four had ureteral reflux (P=0.02) and four of four developed hydronephrosis (P=0.002). All urinary bladders in the present cohort enlarged to expected normal or nearnormal capacities. Serum creatinines were stable throughout the entire follow-up period, with the exception of one patient who had rejection episodes. Two patients had urinary tract infections posttransplantation, but there were no episodes of acute pyelonephritis.

CONCLUSIONS

This novel technique for ureteral implantation successfully capitalizes on the regenerative potential of the bladder mucosa, resulting in a physiological, anatomically natural, and very effective neosubmucosal tunnel. It appears to guarantee success against both ureteral reflux and obstruction, no matter how small the urinary bladder, and offers no hindrance to enlarging the bladder to near normal capacity posttransplantation. The implantation technique is simple and safe, and its use should eliminate the reluctance to use these bladders. Moreover, this procedure offers a major incentive for the successful rehabilitation of small, defunctionalized, nonneurogenic bladders after kidney transplantation.

Vesicoureteral reflux following transurethral resection of bladder tumors

Vesicoureteral reflux after transurethral resection of bladder tumors is a significant complication (19 per cent incidence in the present series). Although most patients with such reflux suffer no apparent ill effects renal destruction occurs in some. Other implications are discussed and the obligation for recognition of the reflux when it exists is emphasized. A simple technique for routine diagnosis is suggested.