Clinical Effectiveness and Prognostic Indicators of Parasagittal Interlaminar Epidural Injection.

Background: Interlaminar epidural steroid injection (ESI) is a well-established intervention to improve radicular leg pain. However, few studies have demonstrated the prognostic factors for interlaminar ESI.

Objective: To investigate the clinical effectiveness and prognostic indicators of parasagittal interlaminar ESI during a 2-week follow-up.

Study Design: Prospective evaluation.

Setting: An interventional pain management practice in South Korea.

Methods: After Institutional Review Board approval, parasagittal interlaminar ESI under fluoroscopic guidance was performed in 55 patients with central spinal stenosis. The numerical rating scale (NRS) and the Oswestry Disability Index (ODI) (%) were used to evaluate clinical efficacy and prognostic indicators. To determine the prognostic indicators, treatment outcomes were classified as successful (decreased NRS ≥ 50%, decreased ODI ≥ 40%) and unsuccessful (decreased NRS < 50%, decreased ODI < 40%) results.

Results: Parasagittal interlaminar ESI significantly improved the NRS and ODI (%) scores after 2 weeks compared to those measured pretreatment. Paresthesia provocation (P = 0.006) was a significant prognostic factor on the NRS, whereas the Beck Depression Inventory (BDI) score (P = 0.007), paresthesia provocation (P = 0.035), and epidurography finding (P = 0.038) were significant on the ODI (%) score between patients with successful and unsuccessful outcomes.

Limitations: We included the method of parasagittal interlaminar ESI only, therefore, direct comparison with other techniques was not available.

Conclusion: Parasagittal interlaminar ESI significantly improved the NRS and ODI (%) scores. Paresthesia provocation was a prognostic indicator on the NRS and ODI (%) scores, and BDI scores and epidurography findings were prognostic indicators for the ODI (%) score.