Lateral Parasagittal Versus Midline Interlaminar Lumbar Epidural Steroid Injection for Management of Low Back Pain with Lumbosacral Radicular Pain: A Double-Blind, Randomized Study

BACKGROUND:Epidural steroid injections are commonly used for management of low back pain with lumbosacral radicular pain and can be administered by either interlaminar or transforaminal routes. The transforaminal route is reported to be more effective than the interlaminar route due to higher delivery of drug at the ventral epidural space. However, the transforaminal route has been associated with serious complications including spinal cord injury and permanent paralysis. Hence, there is a search for a technically better route with fewer complications for drug delivery into the ventral epidural space. Recently, a parasagittal interlaminar (PIL) approach of epidural contrast injection was reported to have 100% ventral epidural spread. However, the therapeutic efficacy of this route has never been investigated. We compared the therapeutic efficacy of the PIL approach and midline interlaminar (MIL) approach. We hypothesized that the PIL approach may produce a better clinical outcome because of better ventral epidural spread of the drug compared with MIL approach. METHODS:Thirty-seven patients were randomized to receive injection of 80 mg methylprednisolone either by the PIL (PIL group, n = 19) or MIL (MIL group, n = 18) approach under fluoroscopic guidance. Patients were evaluated for effective pain relief (≥50% from baseline) by visual analog scale and improvement in disability by the modified Oswestry Disability Questionnaire at intervals of 15 days, 1, 2, 3, and 6 months. Patients having