Skeletal health after intestinal bladder augmentation: findings in 54 patients

To evaluate the risk of osteopenia in patients after intestinal bladder augmentation.

In all, 54 patients with bladder augmentation were evaluated during the regular follow-up programme. Augmentation was performed because of paediatric neurogenic or non-neurogenic reasons. Areal bone mineral densities (aBMD) for the lumbar spine (L1-L4), femoral neck and whole body were measured with dual-energy X-ray absorptiometry. In addition, acid-base balance and plasma 25-hydroxyvitamin D (vitamin D), kidney and gonadal functions as well as body mass index (BMI) were measured. Findings were correlated with clinical characteristics.

BMD was reduced in 34 (63%) of the 54 patients. There was a significant difference in the prevalence of decreased aBMDs between neurogenic and non-neurogenic groups 31 of 42 patients (74%) and three of 12 patients, respectively (P < 0.01). There were spinal compression fractures in 23% of patients. Risk factors for osteoporosis were inability to walk, renal insufficiency, hypogonadism, vitamin D deficiency, acidosis, and a low BMI. There was moderate or severe vitamin D deficiency in 42% of patients but the vitamin D status did not correlate with BMD. The glomerular filtration rate correlated to the whole-body aBMD (P = 0.04). In 26% of patients (predominantly males with myelomeningocele) plasma follicle-stimulating hormone levels were elevated, indicating variable degrees of hypogonadism. Hypogonadism was associated with reduced lumbar spine aBMD (P = 0.03).

Patients with paediatric reasons for bladder augmentation are at risk of osteopenia and compression fractures. The risk factors are mostly related to the patient's underlying illness and not to the augmentation per se.