Abstract
BACKGROUND: Particulate steroids are thought to exert their effects for long durations at injection sites. However, these types of steroids carry higher risks when used in epidural steroid injections. Catastrophic spinal cord complications, including sudden-onset paraplegia, have been reported due to intravascular particulate steroid preparations that cause embolisms and occlusion of blood vessels, resulting in spinal cord infarctions. Clinicians, therefore, recommend nonparticulate steroids to mitigate these adverse events. To our knowledge, this is the first retrospective study that addresses the effectiveness and safety of methylprednisolone, dexamethasone, and betamethasone when used in transforaminal epidural steroid injections (TFESIs) for the treatment of lumbar radiculopathy. OBJECTIVES: The primary goal of this study was to compare the proportion of patients who received injections of particulate steroids and required zero repeat injections within 12 months of their initial injection to the proportion of patients who received injections of nonparticulate steroids and also required zero repeat injections, as well as to compare the number of patients in the particulate cohort who required one or more repeat injections within 12 months of their initial injection to the number of patients in the nonparticulate cohort who required the same. The secondary goal was to evaluate the proportion of patients ultimately requiring surgery. STUDY DESIGN: This is a single-center, IRB-approved, retrospective study evaluating the safety and effectiveness of nonparticulate as compared to particulate steroid medications when used in TFESIs as minimally invasive treatments for chronic lumbar radiculopathy. SETTING: This study captured data (n = 1717) over a 4-year time frame (01/15/2018 to 01/15/2022). METHODS: The following data were collected from each patient’s chart: age, gender, BMI, race, date of initial injection, number of repeat injections at the same lumbosacral level and on the same side within 12 months of the initial injection, and lumbar surgery date (if applicable). Inclusion criteria included: 1) having chronic low back pain of radicular etiology; 2) being at least 18 years old; 3) having experienced the failure of conservative therapy after 12 weeks (including physical therapy and/or medications); 4) having positive physical exam findings supporting nerve impingement (straight leg raise, slump test); and 5) showing lumbar MRI evidence of nerve impingement from disc herniation. Exclusion criteria included: 1) having received prior lumbar surgery at any level (L1-S1); 2) having been given prior TFESIs fewer than 6 months prior to initial injection; 3) having contracted a systemic infection at the proposed injection site; 4) undergoing active cancer treatment; and 5) having gotten any other spine injections. RESULTS: A significantly greater proportion of patients in the nonparticulate steroid cohort received 0 repeat injections (87.5% vs 71.4%, P < 0.001). The particulate steroid cohort demonstrated a significantly greater proportion of patients who received repeat injections within 12 months after the initial injections (12.5% vs 29.6%, P < 0.001). There were no significant differences among patients requiring surgery between the 2 cohorts. Other outcome measures included the identification of risk factors significantly associated with repeat injections. There was a statistically significant weak positive correlation between age and repeat injections (Pearson corr = 0.102; P < 0.001) and a weak negative correlation between ethnicity/race and repeat injections (point-biserial corr = -0.093; P < 0.001). No adverse events were reported. LIMITATIONS: Not all clinicians included in this study used each of the 3 steroid types, and all clinicians used either particulate or nonparticulate steroids exclusively. CONCLUSIONS: Our study demonstrates that the clinical outcomes associated with TFESIs of nonparticulate steroids are superior to those associated with TFESIs of particulate steroids when either variety of medication is used to treat lumbar radiculopathy. This is the first study to include a clinically useful predictive model using information on laterality, age, and steroid type.