Longitudinal changes in bone in men with spinal cord injury.

Abstract

Quantitative bone assessment today is primarily based on the analysis of bone mineral density (BMD). The geometric and structural properties of bone, which are important parameters for skeletal strength, are generally not considered in the routine clinical assessment of spinal cord injury-related osteopenia. To study changes in structural and geometric properties of tibia bone longitudinally by means of peripheral quantitative computerized tomography and a biomechanical test method (bone stiffness measurement device Swing) in 12 subjects with spinal cord injury. Measurements were conducted in the 5th week and around the 104th week after the spinal cord injury in a university hospital. Paired Student's t-tests showed a significant decrease in trabecular (p < 0.05) and cortical bone (p < 0.05), as well as a significant decrease in geometric properties of tibia bone (p < 0.05) within two years after the spinal cord injury. Phase velocity propagation changed in three subjects within two years following the spinal cord injury. This study indicates that beside changes in tissue composition, changes in bone geometric indices and in structural properties occur in the lower extremity after a spinal cord injury. In the tibia, consideration of geometric and biomechanical parameters of bone combined with bone mineral density measurements could result in an improved screening for spinal cord injury-related osteopenia and the prediction of fracture risk in spinal cord injury.