THE IMPACT OF LUMBAR EPIDURAL STEROID INJECTION ON NEUROPATHIC PAIN: A PROSPECTIVE OBSERVATIONAL STUDY.

Objective: To study whether neuropathic or nociceptive pain was better improved after an epidural steroid injection. Study Design: Prospective study. Place and Duration of Study: Department of Orthopaedics, VYDEHI INSTITUTE OF MEDICAL SCIENCES AND RESEARCH CENTRE, BANGALORE, from Jan 2023 to Mar 2024. Background: Low back pain (LBP) can result from conditions such as disc herniation, spinal stenosis, or facet syndrome. It may manifest as either nociceptive pain or neuropathic pain (NP), with neuropathic pain being a signicant factor in chronic LBP. While lumbar epidural steroid injections (ESI) are recognized as an effective treatment for LBP, their effects on nociceptive and neuropathic pain have not been separately evaluated. This study aimed to determine whether ESI provides greater improvement in neuropathic or nociceptive pain. Methods: This prospective study classied patients based on their preprocedure painDETECT questionnaire (PD-Q) scores. A PD-Q score of ≤12 indicated nociceptive pain, while a score of ≥19 indicated neuropathic pain (NP). Patients received either a transforaminal (TF) or interlaminar (IL) epidural steroid injection (ESI). The PD-Q was completed by each patient both before the ESI (baseline) and four weeks afterward. Outcomes were evaluated one month after the ESI using the numerical rating scale (NRS), the short-form McGill Pain Questionnaire (MPQ), and the revised Oswestry Back Disability Index (ODI). Results:A total of 114 patients participated in the study, with 54 classied into the nociceptive pain group (PD-Q score ≤12) and 60 into the neuropathic pain group (PD-Q score ≥19). One month posttreatment, both groups demonstrated signicant reductions in their mean NRS scores. However, despite these improvements, there were no signicant differences in MPQ or ODI scores between the nociceptive and neuropathic pain groups. Following the procedure (TF-ESI or IL-ESI), PD-Q scores in the nociceptive group (n = 54) remained unchanged. In the neuropathic group (n = 41), 13 patients shifted to a PD-Q score <12, and 15 patients had PD-Q scores between 13 and 18. Conclusion: ESI proved effective for short-term relief of both nociceptive and neuropathic pain, suggesting its potential to address the neuropathic pain component in patients with low back pain.