Comparing the effects of epidural methylprednisolone acetate injected in patients with pain due to lumbar spinal stenosis or herniated disks: a prospective study

OBJECTIVE: Satisfactory results have been seen with epidural steroid injections (ESI) in patients with herniated disks (HD), but the role in lumbar spinal stenosis (LSS) has been less investigated. We compared long-term effects of ESI in HD and LSS patients. METHODS: In a prospective, single-blind uncontrolled study, 60 patients with radicular pain due to HD (n = 32) or LSS (n = 28) were enrolled over a 9-month period. Methylprednisolone acetate 80 mg plus 0.5% bupivacaine 10 mg were diluted in normal saline up to a total volume of 10 mL, and injected into the epidural space. The amount of pain based on numeric pain score, level of activity, and subjective improvement were reported by patients after 2 and 6 months by telephone. Demographic data were analyzed with the chi-square test. The differences in numeric pain scale scores between the two groups at different times were analyzed with the t-test. RESULTS: There were no differences between HD and LSS patients regarding age, sex, and average duration of pain prior to ESI. The degree of pain was significantly higher in LSS patients in comparison with HD patients in the pre-injection period. The amount of pain was significantly reduced in both groups 2 months after injection. This pain reduction period lasted for 6 months in the HD group, but to a lesser extent in LSS patients (P < 0.05). DISCUSSION: Epidural methylprednisolone injection has less analgesic effect in LSS, with less permanent effect in comparison with HD.