Cervical Interlaminar Epidural Steroid Injection for Unilateral Cervical Radiculopathy: Comparison of Midline and Paramedian Approaches for Efficacy

OBJECTIVE The objective of this study was to compare the clinical outcomes of the cervical interlaminar epidural steroid injection (CIESI) for unilateral radiculopathy by the midline or paramedian approaches and to determine the prognostic factors of CIESI. MATERIALS AND METHODS We retrospectively analyzed 182 patients who underwent CIESI from January 2009 to December 2012. Inclusion criteria were no previous spinal steroid injection, presence of a cross-sectional image, and presence of follow-up records. Exclusion criteria were patients with bilateral cervical radiculopathy and/or dominant cervical axial pain, combined peripheral neuropathy, and previous cervical spine surgery. Short-term clinical outcomes were evaluated at the first follow-up after CIESI. We compared the clinical outcomes between the midline and paramedian approaches. Possible prognostic factors for the outcome, such as age, gender, duration of radiculopathy, and cause of radiculopathy were also analyzed. RESULTS Cervical interlaminar epidural steroid injections were effective in 124 of 182 patients (68.1%) at the first follow-up. There was no significant difference in the clinical outcomes of CIESI, between midline (69.6%) and paramedian (63.7%) approaches (p = 0.723). Cause of radiculopathy was the only significant factor affecting the efficacy of CIESI. Patients with disc herniation had significantly better results than patients with neural foraminal stenosis (82.9% vs. 56.0%) (p < 0.001). CONCLUSION There is no significant difference in treatment efficacy between the midline and paramedian approaches in CIESI, for unilateral radiculopathy. The cause of the radiculopathy is significantly associated with the treatment efficacy; patients with disc herniation experience better pain relief than those with neural foraminal stenosis.