Epidural steroid injections compared with gabapentin for lumbosacral radicular pain: multicenter randomized double blind comparative efficacy study

OBJECTIVE To evaluate whether an epidural steroid injection or gabapentin is a better treatment for lumbosacral radiculopathy. DESIGN A multicenter randomized study conducted between 2011 and 2014. Computer generated randomization was stratified by site. Patients and evaluating physicians were blinded to treatment outcomes. SETTINGS Eight military, Veterans Administration, and civilian hospitals. PARTICIPANTS 145 people with lumbosacral radicular pain secondary to herniated disc or spinal stenosis for less than four years in duration and in whom leg pain is as severe or more severe than back pain. INTERVENTIONS Participants received either epidural steroid injection plus placebo pills or sham injection plus gabapentin. MAIN OUTCOME MEASURES Average leg pain one and three months after the injection on a 0-10 numerical rating scale. A positive outcome was defined as a >= 2 point decrease in leg pain coupled with a positive global perceived effect. All patients had one month follow-up visits; patients whose condition improved remained blinded for their three month visit. RESULTS There were no significant differences for the primary outcome measure at one month (mean pain score 3.3 (SD 2.6) and mean change from baseline -2.2 (SD 2.4) in epidural steroid injection group versus 3.7 (SD 2.6) and -1.7 (SD 2.6) in gabapentin group; adjusted difference 0.4, 95% confidence interval -0.3 to 1.2; P=0.25) and three months (mean pain score 3.4 (SD 2.7) and mean change from baseline -2.0 (SD 2.6) versus 3.7 (SD 2.8) and -1.6 (SD 2.7), respectively; adjusted difference 0.3, -0.5 to 1.2; P=0.43). Among secondary outcomes, one month after treatment those who received epidural steroid injection had greater reductions in worst leg pain (-3.0, SD 2.8) than those treated with gabapentin (-2.0, SD 2.9; P=0.04) and were more likely to experience a positive successful outcome (66% v 46%; number needed to treat=5.0, 95% confidence interval 2.8 to 27.0; P=0.02). At three months, there were no significant differences between treatments. CONCLUSIONS Although epidural steroid injection might provide greater benefit than gabapentin for some outcome measures, the differences are modest and are transient for most people.