Parameters associated with efficacy of epidural steroid injections in the management of postherpetic neuralgia: the Mayo Clinic experience

Purpose: Thirty percent of patients with postherpetic neuralgia (PHN) receiving conservative treatment report unsatisfactory pain relief. Epidural steroid injections (ESIs) are commonly used as a therapeutic intervention in these patients. In this study, we aimed to determine if there are variables that predict the efficacy of ESI in patients with PHN. Patients and methods: We retrospectively identified patients seen at Mayo Clinic who had PHN and received ESI. From their medical records, we abstracted the demographic variables, concurrent medication use, anatomic approach and medication for ESI, and degree of pain relief at 2 and 12 weeks' postintervention. Results: None of the studied variables were significantly associated with efficacy of ESI in patients with PHN. PHN that began <11 months before treatment was predictive of a response to ESI at 12 weeks postintervention (positive predictive value, 55%). Patients who reported poor ESI efficacy 2 weeks after the intervention had a 94% chance of still having pain at 12 weeks. Conclusion: For this cohort of patients with PHN being treated with ESI, no demographic characteristics, concurrently used medications, or type of ESI were associated with ESI treatment efficacy at 2 or 12 weeks after the intervention.