SI-6603 Versus Placebo in Patients With Lumbar Disc Herniation

Inclusion Criteria: * Patients with lumbar disc herniation (L4-L5 or L5-S1) as assessed by MRI and clinical symptoms corresponding to position of the impaired nerve root * Patients assessed as positive in the SLR test * Patients with sciatica in either lower leg * Patients with no improvement from pharmacotherapy or concomitant treatment with drug and nerve block Exclusion Criteria: * Patients who have 2 or more lumbar disc herniations as assessed by MRI * Patients with "extrusion-type" or "sequestration-type" herniation in whom a rupture into the posterior longitudinal ligament is identified by MRI * Patients who have received nerve block within 3 weeks before screening * Patients who have undergone lumbar operation, chemonucleolysis, or percutaneous nucleotomy