Effect of Epidural Steroid Injection on Bone Mineral Density and Markers of Bone Turnover in Postmenopausal Women

Study Design. A prospective, observational study. Objective. To evaluate the effect of epidural steroid injection (ESI) on bone mineral density (BMD) in postmenopausal women. Summary of Background Data. ESIs are used to treat the pain associated with radiculopathy. Although it is known that exogenous steroid use can disrupt skeletal architecture, it is less clear whether ESIs result in a decrease of BMD. Methods. Twenty-eight postmenopausal women experiencing radiculopathy elected L4-L5 ESI treatment. We had a 50% dropout rate due to noncompliance with study requirements. BMD of the hip, femoral neck, and spine along with markers of bone turnover, bone specific-alkaline phosphatase and serum C-telopeptide of collagen I (CTX), was evaluated at baseline preinjection and 3 and 6 months postinjection. Results. There was a significant decline in the hip BMD of 0.018 g/cm(2) (0.028 +/- 0.007, P = 0.002) at 6 months compared with baseline. We compared this decline with an age-matched control population that exhibited a decline of 0.003 g/cm(2), significantly less than our study population (P = 0.007). Bone-specific alkaline phosphatase increased significantly by 2.33 U/L from 3 to 6 months (P = 0.012), but the rise of CTX was not significant. Conclusion. A single ESI in postmenopausal women adversely affects BMD of the hip. This is in conjunction with a rise in bone remodeling activity, as evidenced by an increase in bone-specific alkaline phosphatase and CTX. In addition, when compared with an age-matched control population, our study population exhibited a greater decline in BMD. Our findings show that epidural administration of corticosteroids has a deleterious effect on bone, which should be considered when contemplating treatment options for radiculopathy. The resulting decrease in BMD, while slight, suggests that ESIs should be used with caution in those at a risk for fracture.