Exstrophy bladder: effect of sigmoid colocystoplasty on physical growth and bone mineral density

Abstract

Background and Aims: Introduction of intestinal tissue in the urinary tract results in numerous metabolic changes. This study investigates the effects of augmentation sigmoid colocystoplasty on the physical growth and bone mineralization in bladder exstrophy patients. Materials and Methods: Physical growth, serum biochemistry and bone mineral density were assessed pre and post augmentation in 34 of 54 patients who were treated by staged sigmoid colocystoplasty for classical bladder exstrophy during the period 1985-2007. Physical growth was determined by comparing the height and weight for age with standard growth charts. Serum biochemistry included calcium, phosphate and alkaline phosphatase levels. Bone Mineral Density (BMD) was determined at the femoral head using the Dual Energy X-ray Absorptiometry (DEXA) scan at 15 ± 4.5 months after the augmentation. The DEXA scan findings were compared with 22 normal Indian children who served as controls and 18 unaugmented patients with bladder exstrophy. In 13 augmented patients, the DEXA scan could be repeated after an interval of six months. Results: The mean percentile height and weight were comparable in the pre and post-augmentation period with no statistically significant difference (P = 0.135 for height and P = 0.232 for weight). Biochemical parameters of bone metabolism also did not show any statistically significant changes after colocystoplasty. The BMD was 0.665 ± 0.062 g/cm² in the controls and 0.612 ± 0.10 g/cm² in the unaugmented bladder exstrophy patients. In the augmented patients, the BMD was 0.645 ± 0.175 g/cm² and six months later it was 0.657 ± 0.158 g/cm². These differences were not statistically significant. Conclusions: In our study, no significant effects on the physical growth and bone mineral metabolism were observed in exstrophy bladder patients following sigmoid colocystoplasty.