P50. Effect of systemic teriparatide (PTH1-34) versus placebo on bone mineral density (BMD) after lumbar spinal arthrodesis

Abstract

BACKGROUND CONTEXT Patients undergoing decompression and non-instrumented lumbar arthrodesis may have initial bone loss after surgery, increasing their fracture risk. It is uncertain if systemic PTH has a beneficial effect on BMD after surgery. PURPOSE To determine if systemic administration of PTH will have a beneficial effect on hip and spine BMD compared to placebo in patients aged > 60 undergoing decompression and non-instrumented lumbar arthrodesis. STUDY DESIGN/SETTING Secondary analysis of data from a randomized, double-blind placebo-controlled trial of PTH vs placebo to improve fusion quality. PATIENT SAMPLE Patients enrolled in a randomized, double-blind placebo-controlled trial of PTH vs placebo to improve fusion quality. OUTCOME MEASURES Lumbar Spine and Hip BMD based on DXA scans. METHODS Patients received either 20 microgram teriparatide subcutaneously (N=44) or placebo (N=43) daily for 3 months starting day 1 after surgery. DXA scans were performed preoperatively and at 1,3,6 and 12 months post-op. ANCOVA comparing Lumbar Spine and Hip BMD in PTH vs Placebo with smoking, sex, weight, age and baseline BMD as covariates was performed. RESULTS There was a loss of Lumbar Spine BMD at 1 month postop in both groups. There was some improvement in BMD scores in the PTH group at 3 months that was not sustained at 6 and 12 months. There was a loss in Hip BMD in the placebo group at 1 and 3 months postop that was not seen in the PTH group. At 12 months postop, there was a modest decrease in BMD score for the Lumbar Spine and Hip in both groups. CONCLUSIONS Systemic PTH provides short term beneficial effect on BMD compared to placebo in patients undergoing decompression and non-instrumented lumbar arthrodesis. Some of the decline in BMD at 12 months postop is expected due to annual age-related bone loss. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.