Lower Spine Volumetric Bone Density in Patients With a History of Epidural Steroid Injections

Context: Epidural steroid injections (ESIs) are a common, effective treatment of lumbar radiculopathy and sciatica. Although the negative skeletal effects of oral glucocorticoids are well established, little is known about the impact of ESI on bone quality. Objective: To investigate the relationship between ESI exposure and volumetric bone mineral density (vBMD) at the lumbar spine (LS) using central quantitative CT. Design: Retrospective study. Setting: University hospital outpatient facility. Patients: All patients had CT scans of the LS between 2011 and 2016. Cases received at least three ESIs prior to the date of CT (n = 121). Controls were matched for age and sex (n = 121). Main Outcome Measures: Cumulative ESI dose was calculated. vBMD was measured at T12 through L5 using QCT Pro phantomless software (MindWays). Results: Mean age of subjects was 65 +/- 14 years, and 49% were women. Median number of ESIs was 4 (range: 3 to 16). Median cumulative ESI dosage was 340 mg of triamcinolone or equivalent (range: 150 to 1400 mg). Compared with controls, ESI subjects had lower vBMD at each vertebral level. Higher cumulative dose was associated with lower mean vBMD at T12 to L5 (r = -0.22, P = 0.02). Conclusions: Greater cumulative ESI dose was related to lower vBMD at the LS. To our knowledge, this is the first study to measure vBMD in patients treated with ESIs. Prospective studies are needed to confirm these findings and to help identify the best strategies for preventing bone loss in this population.