Characterization of the bone mineral density of children with spinal cord injury.

The purpose of this study was to compare the bone mineral density in children with spinal cord injury (SCI) with age- and sex-matched controls in three anatomic areas of the proximal hip. In addition, post hoc analysis looked for differences in bone density between sub-groups considering several factors associated with spinal cord injury: the presence or absence of spasticity, the level of injury and the presence or absence of pathologic fractures. Fifty-one pediatric patients with spinal cord injury between the ages of 3 and 20 underwent bone density measurements using dual photon absorptiometry. Before pooling the data across age groups, all measurements were normalized to age- and sex-matched controls because of increasing bone density with growth and higher bone density in males. The results revealed lower bone densities in subjects with SCI as compared with their non-disabled peers, ranging from 56 percent to 65 percent of normal across the three anatomic regions. On the average, subjects who had a previous history of fractures had significantly lower bone density measurements than those without fractures. At the intertrochanteric region, a 10.6 percent difference was noted between subjects with tetraplegia versus those with paraplegia. At the femoral neck and Ward's Triangle, an 8.5 percent difference was noted between subjects with and without spasticity. No conclusions could be drawn from the analyses at the other sites. Together these results begin to characterize bone density levels of the pediatric SCI population.