Use of 125I Photon Scanning in the Evaluation of Bone Density in a Group of Patients with Spinal Cord Injury

One hundred patients with spinal cord injury had various parameters of bone mineral estimated. The results were compared to a group of matched normals. A Packard Osteodensitometer with a 125I point source was used to measure bone mineral mass in the distal radius. The cortical bone was found to be normal in the spinal cord injury patients as shown by photon densitometry, and radiographic measurement of the metacarpal and clavicular indices. It was not related to the date or the level of the spinal injury and was related to age in a similar fashion to the normals. However, hand radiographs demonstrated marked loss of trabecular bone in 52 patients (including 14 paraplegics). This suggests that, in spinal cord Injury, cortical bone is preserved while trabecular bone is lost, and because this is dissimilar from idiopathic osteoporosis a possible neuronal etiology is postulated.