Objectives. To describe the extent of pain relief two weeks after an epidural steroid injection in patients with herniated disks and lumbar spinal stenosis, and to identify predictors of changes in pain ratings in each population.
Methods. The study design was a prospective evaluation of patients with lumbar spinal stenosis (LSS) and herniated disks (HDs) referred to a hospital-based pain clinic for an epidural steroid injection (ESI). A complete history, detailed physical examination, comprehensive pain questionnaire, and Brief Symptom Inventory were obtained for all patients. Pain was assessed at baseline and two weeks following a single ESI using a visual analog scale.
Results. Two hundred twelve patients (mean age 54 years) were enrolled, and 78 of these provided pain ratings before and two weeks after the injection. LSS patients improved less two weeks following the ESI than HD patients (P = 0.04). Just 38% of LSS patients reported improvement in pain score compared with 61 % of HD patients. In analyses that combined LSS and HD patients, predictors of worse response included a report of health problems and a diagnosis of LSS.
Conclusions. LSS patients have worse response to ESIs than HD patients. The poor response to ESI in patients with LSS underscores the need for randomized controlled trials of ESI in this population.