title: Use of epidural opioid 'blockade' as an adjuvant diagnostic procedure.
mesh_terms: D000767:Anesthesia, Epidural; D003937:Diagnosis, Differential; D006801:Humans; D009294:Narcotics; D010146:Pain / Q000175:diagnosis*; D011602:Psychophysiologic Disorders / Q000175:diagnosis*
chemical_list: D009294:Narcotics