Evaluation of bone mineral density and morphology using pQCT in children after spinal cord injury

Objective: To evaluate the effects of spinal cord injury (SCI) on bone density and morphology in children using peripheral quantitative computer tomography (pQCT). Design: Retrospective cohort study of 19 paediatric patients with SCI (9 paraplegics and 10 tetraplegics). Results: There was significant reduction in tibial metaphysial volumetric bone mineral density (vBMD), diaphysial cortical cross-sectional area (CSA), cortical thickness and polar strength-strain index. There was a significant loss of calf muscle CSA. Those who were able to stand had greater trabecular vBMD, tibial cortical thickness and tibial muscle CSA Z-scores. Lower limb fractures did not occur if tibial trabecular vBMD was greater than 100mg/cm. Tibial geometry following SCI was more circular compared to controls. Conclusions: pQCT provides a valuable insight into the regional changes in bone and muscle development in children following SCI. Residual muscle function with the ability to weight bear provides a significant benefit to bone development.