The skeletal consequences of epidural steroid injections: a literature review.

This literature review summarized studies that evaluated the effects of epidural steroid injections (ESIs) on skeletal health. While evidence is limited, studies suggest that ESIs may cause bone loss. Better understanding of these skeletal consequences will help foster strategies to prevent bone loss in the growing population of patients receiving ESIs. PURPOSE: Approximately nine million epidural steroid injections (ESIs) are administered annually in the United States to treat radicular back pain. ESIs often provide pain relief and functional improvement. While the overall incidence of adverse events resulting from ESIs is low, their effects on the skeleton are poorly understood. This is an important consideration given the profound skeletal impact of other forms of glucocorticoids. METHODS: Ovid MEDLINE and PubMed search results since 2010, including older, frequently referenced publications were reviewed. RESULTS: Systemic absorption of glucocorticoids occurs after ESI, which can cause hyperglycemia and endogenous cortisol suppression. The majority of studies investigating the skeletal effects of ESIs are retrospective. Several have found a relationship between low areal bone mineral density (BMD) by dual-energy x-ray absorptiometry and ESI exposure, but this finding is not uniform. Recently a dose-response relationship between ESI exposure and low spine volumetric BMD by computed tomography has been reported. Few studies have investigated the relationship between ESI exposure and fracture risk. Results of these studies are conflicting, and most have not been adequately powered to detect fracture outcomes. CONCLUSIONS: While evidence is limited, studies suggest that ESIs may cause bone loss, particularly those investigating volumetric BMD. Larger doses appear to confer greater risk. Further prospective studies are needed to investigate the relationship between ESI and fracture risk. Better understanding of the skeletal consequences of ESIs will help foster strategies to prevent bone loss in the growing population of patients receiving this treatment.

Risk factors for multi-joint disease in patients with glucocorticoid-induced osteonecrosis.

This study investigated risk factors for osteonecrosis involving multiple joints (MJON) among glucocorticoid-treated patients. The best predictor of MJON was cumulative oral glucocorticoid dose. Risk of MJON was 12-fold higher in patients who had a second risk factor for osteonecrosis. Further research is needed into strategies for prevention of MJON. INTRODUCTION: Osteonecrosis (ON) is a debilitating musculoskeletal condition in which bone cell death can lead to mechanical failure. When multiple joints are affected, pain and disability are compounded. Glucocorticoid treatment is one of the most common predisposing factors for ON. This study investigated risk factors for ON involving multiple joints (MJON) among glucocorticoid-treated patients. METHODS: Fifty-five adults with glucocorticoid-induced ON were prospectively enrolled. MJON was defined as ON in ≥ three joints. Route, dose, duration, and timing of glucocorticoid treatment were assessed. RESULTS: Mean age of enrolled subjects was 44 years, 58% were women. Half had underlying conditions associated with increased ON risk: systemic lupus erythematosus (29%), acute lymphoblastic leukemia (11%), HIV (9%), and alcohol use (4%). Mean daily oral dose of glucocorticoids was 29 mg. Average cumulative oral dose was 30 g over 5 years. The best predictor of MJON was cumulative oral glucocorticoid dose. For each increase of 1,000 mg, risk of MJON increased by 3.2% (95% CI 1.03, 1.67). Glucocorticoid exposure in the first 6 months of therapy, peak dose (oral or IV), and mean daily dose did not independently increase risk of MJON. The risk of MJON was 12-fold in patients who had a second risk factor (95% CI 3.2, 44.4). CONCLUSIONS: Among patients with glucocorticoid-induced ON, cumulative oral dose was the best predictor of multi-joint disease; initial doses of IV and oral glucocorticoids did not independently increase risk. Further research is needed to better define optimal strategies for prevention and treatment of MJON.

Low volumetric bone density is a risk factor for early complications after spine fusion surgery.

This study aims to investigate lumbar spine (LS) volumetric bone density (vBMD) as a risk factor for complications (pseudoarthrosis, instrumentation failure, adjacent fractures), re-operation, and time to complication after fusion. INTRODUCTION: Lumbar spine (LS) fusion surgery is increasingly performed worldwide. Complications after fusion result in significant morbidity and healthcare costs. Multiple factors, including osteoporosis, have been suggested to contribute to risk of complications and re-operation. However, most studies have used DXA, which is subject to artifact in patients with spine pathology, and none have investigated the relationship between BMD and timing of post-operative complications. This study aims to investigate LS volumetric bone density (vBMD) as a risk factor for complications (pseudoarthrosis, instrumentation failure, adjacent fractures), re-operation, and time to complication after fusion. METHODS: We evaluated a cohort of 359 patients who had initial LS fusion surgery at our institution, had pre-operative LS CTs and post-operative imaging available for review. Demographic factors, smoking status, vBMD, and details of surgical procedure were related to likelihood and timing of post-operative complications. RESULTS: Mean age was 60 ± 14 years, vBMD 122 ± 37 g/cm3. Median follow-up was 11 months. Skeletal complications occurred in 47 patients (13%); 34 patients (10%) required re-operation. Low vBMD (directly measured and estimated using HU) and smoking were associated with increased risk of skeletal complications. Each increase in baseline vBMD of 10 g/cm3 decreased the complication hazard and increased the complication-free duration in time-to-event analysis (hazard ratio 0.91, 95% CI 0.83-0.98, p < 0.02). CONCLUSIONS: Low vBMD was a significant risk factor for early post-operative complications in patients undergoing LS fusion. Prospective studies are needed to confirm these findings and to elucidate the optimal timing for follow-up and strategies for prevention of post-operative complications in this population.