Enterocystoplasty: The long-term effects on bone mineral density

Studies show that enterocystoplasty has a negative effect on bone mineral density (BMD). The aim of this study was to investigate the long-term impact of enterocystoplasty on BMD. We used dual energy x-ray absorptiometry (DEXA) scans to determine BMD and identify patients with osteopenia and osteoporosis who are at potential long-term risk for fracture.

We reviewed our database of >200 individuals, who had undergone enterocystoplasty or continent diversion for both neurogenic and non-neurogenic reasons during childhood. We chose to study the non-neurogenic group first for a number of technical reasons, and identified 24 individuals who had undergone the procedure for non-neurogenic reasons, and had more than 15 years of follow-up. In addition we had a control group of 10 individuals born with bladder exstrophy, who had undergone primary closure before the year 2000, without enterocystoplasty. We used DEXA scan T- and Z-scores to identify patients with osteopenia and osteoporosis.

Eleven of 24 patients had normal DEXA scans with normal T- and Z-scores; seven had identifiable osteopenia and increased long-term risk for fracture. Six had osteoporosis; three of whom had reduced glomerular filtration rate (GFR). Eight of the 10 individuals in the control group had a normal DEXA scan.

Enterocystoplasty during childhood can lead to loss of BMD. This does not seem to be related to the enterocystoplasty alone. It is more pronounced in individuals who have other risk factors, such as reduced GFR. The identification of BMD loss makes it possible to intervene before osteoporosis occurs and leads to pathologic fracture.