The Effect of Epidural Steroid Injections on Bone Mineral Density and Vertebral Fracture Risk: A Systematic Review and Critical Appraisal of Current Literature
Christy Hunt and Panagiotis Kerezoudis, et al
Background: Epidural steroid injections (ESI) are used in the nonsurgical management of radiculopathy refractory to more conservative care. It is well established that glucocorticoids (GCs) have multiple systemic effects by maintaining and regulating a multitude of immune and circulatory functions. GCs affect bone mineral density via multiple mechanisms including stimulation of osteoclast-mediated bone resorption while reducing osteoblast-mediated bone formation. Recent studies have yielded conflicting results regarding the effect of ESI on bone mineral density (BMD) and whether frequent injections and increased exposure over time result in an increased risk of osteoporosis and vertebral fracture. Therefore, we carried out a systematic review of current literature to examine the effect of ESI on BMD and fracture with the aim of updating current knowledge and providing directions for future research in this field.
Methods: IRB approval was waived for this systematic review. This study was conducted according to the guidelines in the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA). A master’s level librarian queried PubMed/MEDLINE, Embase, Scopus and Cochrane for our electronic searches (last date of search, March 1, 2017). Data were collected from published studies from all available years. Keywords included the Boolean search string: “epidural steroid injections” AND “osteoporosis” or “osteopenia” or “vertebral fracture” or “bone mineral density.”
Results: Our search strategy yielded a total of 389 studies. Eight articles were eventually included for qualitative and quantitative analysis. All of the included studies were single-institutional, observational cohort studies (2 cross-sectional, 4 retrospective cohorts, and 2 prospective). Included studies reported data from a total of 7233 patients. Six studies evaluated BMD and two studies examined vertebral fracture risk as the primary outcome of interest. All eight studies had a case group of patients that received ESI per the eligibility criteria. Six out of the eight studies had a control group. In the remaining two studies the effect of ESI was assessed against baseline measurements. Risk of bias was rated as low in three studies and as moderate in five studies. Low BMD was present in 52.5% to 96.2% (lumbar spine) and 29% to 93.5% (femoral neck) of patients that received ESI.
Conclusions: According to the current literature, although controversial, ESIs seem to decrease BMD, both locally (lumbar spine) and systemically (femoral neck) in doses as low as 80 mg of MP equivalents and increase the risk of vertebral fracture. Future studies will hopefully further delineate the safety profile associated with epidural steroids.