Preventing reservoir calculi after augmentation cystoplasty and continent urinary diversion: the influence of an irrigation protocol

OBJECTIVE: To evaluate the influence of an irrigation protocol in preventing reservoir calculi forming after augmentation cystoplasty and continent urinary diversion. PATIENTS AND METHODS: Between 1985 and 1995, 91 patients had an augmentation cystoplasty and/or continent urinary diversion (group 1; 54 females and 37 males, mean age 11.1 years, range 1-31); these patients were not routinely instructed to use irrigation after surgery. The segments used included ileum (44), colon (36), stomach (eight) and ureter (three). Between 1995 and 2000, 42 patients (group 2) underwent urinary reconstruction (22 females and 20 males, mean age 14.8 years, range 4-27), the segment used being ileum (30), colon (five), ureter (five) and stomach (two) but in contrast to group 1 they then were placed on a standard prophylactic irrigation protocol. The occurrence of stones in the reservoir was then assessed. RESULTS: Thirty-nine of the 91 patients (42.8%) in group 1 presented with reservoir calculi after reconstruction and 22 had several episodes. The mean time to presentation was 30 months. The incidence of stone formation by underlying diagnosis included: myelomeningocele, 32/48 (66%), exstrophy five/25 (25%), posterior urethral valves two/20 (10%) and rhabdomyosarcoma, none of three. Fifty of the 91 patients had an abdominal stoma, with stone formation in 33 (66%), while 41 used the native urethra, with stone formation in six (15%). Three (7%) of the 42 patients in group 2 developed reservoir calculi after reconstruction, two in patients with myelomeningocele and one in a trauma patient who had residual bone spicules in the bladder; the mean time to presentation was 26.5 months. CONCLUSIONS: These data suggest that the irrigation protocol used in group 2 significantly reduced the number of reservoir calculi after urinary tract reconstruction when bowel was used as part of the reconstruction (43% vs. 7%). The most calculi in both groups were in immobile patients with sensory impairment. Also, patients with an abdominal stoma had a greater risk of reservoir calculi (66%) than those using the native urethra (15%).