[Diagnostic and therapeutic instruments for the pain clinic: introduction]

Pain, a very unpleasant feeling often difficult to treat, is the most common complaint of patients visiting hospital. When a patient with pain visits our institution, first of all, we have to diagnose the pain including the grade of pain and stress associated with sympathetic-adrenal-medullary system. We then treat the pain of the patient using available devices. In the following special articles, functional magnetic imaging, device for measurement of salivary alpha-amylase and PainVisionTM for pain measurement are described as devices for diagnosis of pain. As devices for treatment of pain, epidural infuser pump, intrathecal infusion pump, spinal cord stimulation device and phototherapy device are also described. The mechanism and grade of intractable pain often confuse us to recognize pain. The devices, described in this special issue, are very useful for the evaluation and treatment of intractable pain. I feel happy if these articles greatly contribute to the treatment of patients with pain by pain clinicians.