The effect of intestinal urinary reservoirs on renal function: a 10-year follow-up

Objective To study the effect of the storage of urine in intestinal reservo irs on long-term renal function and the possible causes of deterioration. Patients and methods Eighty-seven patients (aged 4-35 years) with bladder e xstrophy who underwent reconstruction of the lower urinary tract using a bo wel segment were enrolled in a prospective protocol. The glomerular filtrat ion rate (GFR) was measured before and after surgery at 1, 2, 5 and 10 year s using Cr-51-ethylenediamine tetra-acetic acid, Patients with a decline in GFR of > 5% were investigated to identify the cause. Results Of 58 patients with a follow-up of greater than or equal to 10 year s, 53 were evaluable, four having been lost to follow-up and one refusing t o accept the protocol. In these 53 patients, the mean (SD) GFR decreased fr om 97.9(20.4) to 92.9 (23.6) mL/min/1.73 m(2) (P=0.24), However, this decre ase was accounted for by 10 patients (19%) whose GFR fell by greater than o r equal to 20% over the 10 years. The causes of renal deterioration in thes e 10 patients were; chronic retention and/or infection caused by inadequate catheterization in poorly compliant patients (five), uretero-ileal stenosi s (one), a high-pressure reservoir (one) and uncertain causes (three). Conclusions For 80% of the patients, the storage of urine in intestinal res ervoirs did not change renal function for at least 10 years. However, appro ximate to 20% of patients had some deterioration in renal function during t he 10-year follow-up, usually from identifiable and remediable causes. The storage of urine in bowel does not appear to be inherently damaging to kidn ey function. Patients with an enterocystoplasty need regular monitoring of renal function; when deterioration is detected the urinary tract must be fu nctionally assessed.