Premedication With Melatonin in Lumbar Medial Branch Block Procedure

Lumbar medial branch blocks are commonly used as a diagnostic tool for facet-mediated chronic low back pain. This interventional pain procedure often occurs in the fluoroscopy suite. During this procedure, a physician inserts the needles to deliver local anesthetics such as lidocaine or bupivacaine to the nerves which innervate the lumbar facet joint. Many patients experience anxiety before and during the lumbar medial branch block procedure and require intravenous midazolam or fentanyl for sedation. Intravenous or conscious sedation requires one-to-one nursing care, monitoring, and recovery. In order to minimize the costs and time requirements of intravenous sedation, a suitable oral medication which is readily available and non-controlled would be ideal. Several randomized double-blinded, controlled trials have investigated the anxiolytic effects of melatonin before a surgery; however no studies to date have studied the anxiolytic effects of melatonin before less invasive interventional pain procedures. This study is designed to evaluate the efficacy of melatonin for reducing anxiety in patients undergoing a lumbar medial branch block procedure. The study is a randomized, double-blinded, placebo-controlled trial with 40 patients in each group: 2 mg melatonin, 10 mg melatonin and placebo. The primary outcome is anxiety reduction in patients before undergoing the procedure. The primary outcome is measured by visual numerical rating scale for anxiety and the Amsterdam Preoperative Anxiety and Information Scale. Based on the results of previous studies, the investigators hypothesize that melatonin may reduce anxiety in patients undergoing the procedure and be a suitable alternative to intravenous sedation in the pain clinic for patients undergoing lumbar medial branch blocks.