Intravenous pamidronate attenuates bone density loss after acute spinal cord injury.

OBJECTIVE To compare the effects of a 6-month treatment with intravenous pamidronate (30-mg infusion once per month) to conventional rehabilitation without pamidronate on bone density of the spine and leg bones and on the excretion rate of N-telopeptide, a urinary marker of bone catabolism, in acutely spinal cord injured patients. DESIGN A nonrandomized control trial in which 24 spinal cord injured subjects entered the study within 6 weeks of their injury. Fourteen subjects received pamidronate; 10 did not. OUTCOME MEASURES Bone density measurements by dual x-ray absorptiometry were performed before the initial treatment (within 6 weeks of the injury) and at 3, 6, and 12 months postinjury and was the primary efficacy parameter. Urine for N-telopeptide levels was the secondary efficacy parameter. RESULTS After acute spinal cord injury, patients treated with intravenous pamidronate had significantly less bone density loss compared with those who did not receive pamidronate (parametric ANOVA, p<.02). Also, ambulatory subjects had significantly less bone density loss over the study period (p<.05) than nonambulatory subjects. In general, a high excretion level of the urinary bone-breakdown product N-telopeptide was found before intravenous pamidronate treatment, followed by a dramatic reduction in excretion after pamidronate treatment. Ambulatory subjects excreted significantly less N-telopeptide than motor-complete subjects at all time points. CONCLUSION Intravenous pamidronate treatment and ambulatory ability in the first 6 months after an acute spinal cord injury prevents bone density loss.