Transforaminal Versus Lateral Parasagittal Versus Midline Interlaminar Lumbar Epidural Steroid Injection for Management of Unilateral Radicular Lumbar Pain: A Randomized DoubleBlind Trial

Background: Epidural steroid injections (ESIs) are commonly used for management of lumbosacralradicular pain. Midline interlaminar (MIL) or transforaminal (TF) routes are commonly used. TheTF route, although associated with higher delivery of drug to the ventral epidural space, hasserious complications including spinal cord injury and permanent paralysis reported in literature.Therefore, there is a search for a technically better route with fewer complications and greaterdrug delivery into the ventral epidural space. Recently, a parasagittal interlaminar (PIL) approachhas been defined.Objectives: We conducted this study to compare therapeutic effectiveness of 3 techniques ofESIs in patients having unilateral lumbar radiculopathy. Further, effect of ESI on bone mineraldensity (BMD) and serum osteocalcin levels were studied.Study Design: Randomized double-blind trial.Setting: Pain clinic of a tertiary care hospital.Methods: Sixty-five patients were randomly allocated into group MIL, group PIL, and group TF toreceive epidural injection with 80 mg of methylprednisolone and 2 mL of 2% lidocaine. Effectivepain relief and improvement in disability were assessed using Visual Analog Scale (VAS) andModified Oswestry Disability Questionnaire (MODQ) scores at 2 weeks, 4 weeks, 3 months, and6 months, respectively. Patients with < 50% relief received additional injection. Primary outcomeof study was effective pain relief at 6 months. Mean change in VAS and MODQ scores, BMD, andserum osteocalcin levels were secondary outcome assessed.Results: Patients having effective pain relief were significantly higher in group PIL (16 of 20[80%]) and group TF (15 of 20 [75%]) compared with group MIL. Patients receiving ESI in groupPIL and group TF showed significantly lower VAS scores than group MIL (P = 0.02, P = 0.50 at3 months and P = 0.00, P = 0.02 at 6 months, respectively). Mean MODQ scores in group PILand group TF were significantly lower than group MIL. However, group PIL and group TF did notsignificantly differ in MODQ scores. There was no significant change in serum osteocalcin andBMD, as assessed by dual energy x-ray absorptiometry scan at 3 months.Limitations: The absence of a placebo control group, small sample size, and relatively shortfollow-up of 6 months were limitations.Conclusions: PIL approach is equivalent to TF and superior to MIL approach in terms of effectivepain relief and decrease in disability in patients with unilateral lumbar radiculopathy. This studyshowed no deleterious effect on BMD.Key words: Epidural steroid, technique, efficacy, bone marrow density, serum osteocalcin