Lumbar transforaminal epidural steroid injections: Does immediate post-procedure pain response predict longer term effectiveness?

Objective: To assess whether the immediate anesthetic response of pain relief (sensory blockade) or weakness (motor blockade) after lumbar transforaminal epidural steroid injection (TFESI) is associated with longer term effectiveness in pain relief and functional recovery. Design: Retrospective observational study. Setting: Single academic radiology practice. Subjects: Three thousand six hundred forty-five lumbar TFESIs performed on 2,634 subjects. Methods: Subjects completed a pain numerical rating scale (NRS, 0-10) and Roland-Morris disability questionnaire (R-M) prior to and immediately after TFESI (NRS) and at 2 weeks and 2 months follow-up. Successful pain relief was ≥50% NRS reduction; functional success was ≥40% R-M reduction. Post-procedure motor weakness was recorded. Logistic regression models assessed association of immediate post-procedure NRS response, and NRS or R-M response at 2 weeks, with successful outcomes at 2 months. C-index assessed model discrimination; values closer to 1.0 indicated better discrimination. Results: Immediate NRS response was weakly associated with 2-month outcomes (C-index=0.58). NRS and R-M responses at 2 weeks were more strongly associated with the 2-month response (C-indices 0.77, 0.80, respectively). Post-procedure motor blockade had little association with successful 2-month NRS or R-M outcomes (C-indices 0.51, 0.50, respectively). Patients that responded at 2 weeks were more likely to be responders at 2 months than those who were non-responders at 2 weeks (odds ratio=6.49, confidence interval 5.38, 7.84). Conclusion: Immediate post-TFESI pain relief does not strongly predict longer term effectiveness in pain relief or functional recovery. Response in pain relief or functional recovery at 2 weeks is more strongly associated with 2-month outcomes.