Intravenous pamidronate attenuates bone density loss after acute spinal cord injury

Abstract

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.