Long-term evaluation of metabolic profile and bone mineral density after ileocystoplasty in children.

PURPOSE

We evaluated the long-term effects of ileocystoplasty on linear growth, serum electrolytes, acid-base profile and bone mineral density (BMD) in a group of neurologically intact children with a mean followup of 8.9 years.

MATERIALS AND METHODS

Between 1988 and 1997, 9 girls and 16 boys with a mean age of 6 years (range 1 month to 14 years) underwent ileocystoplasty for etiologies other than myelomeningocele and neuropathic bladder. Indications for ileocystoplasty were small noncompliant bladder secondary to bladder exstrophy in 12 cases, bladder outlet obstruction in 10 and post-partial cystectomy for rhabdomyosarcoma in 3. All patients underwent clinical evaluation, supine height measurement, serum electrolytes, arterial blood gases and BMD measurement using a fan beam dual energy absorpitometry scan. BMD was measured at L1-L4 and corrected for age and sex.

RESULTS

Followup ranged from 4 to 13 years (mean 8.9). Serum creatinine was normal in 20 of the 25 patients. All patients had normal supine height measurement with a mean of 45th (+/- 9) centile on growth charts. Serum electrolytes, calcium, phosphorus and arterial blood gases were normal in all patients. Mean BMD corrected for age and sex was 89 (+/- 10)%. BMD was normal in 17 of 25 (68%) patients. Mild reduction in bone density between 1 and 2 standard deviations below the age/sex mean was documented in 3 (12%) patients and the remaining 5 (20%) showed marked osteopenia of 2 or more standard deviations. Of the latter 5 patients 2 had increased serum creatinine, 1 had a history of radiotherapy for pelvic rhabdomyosarcoma and 2 had cloacal exstrophy and short bowel, all of which might have contributed to the osteopenia.

CONCLUSIONS

Ileocystoplasty for children with normal kidney function is not associated with alterations in serum electrolytes or arterial blood gases in the long term. However, 32% of patients showed variable degrees of reduction in BMD. Although marked reduction in BMD was associated with cofactors, 12% of patients had evidence of mild osteopenia in absence of those cofactors. We recommend routine preoperative and longitudinal followup BMD measurements for children undergoing intestinal bladder augmentation.