The incidence of chronic pain among the adult Japanese population has been reported to be around 23%. In the majority of cases, the site of chronic pain is located in the musculoskeletal system, such as the lumbar spine, neck and shoulder joint. Based on the pain mechanism, musculoskeletal chronic pain is classified as chronic nociceptive pain, neuropathic pain or mixed pain. Psycho–social factors often affect clinical symptoms in chronic pain cases.
The first choice of medication for chronic nociceptive pain, resulting from conditions such as inflammation or degeneration of joints or spine, is nonsteroidal anti–inflammatory drugs (NSAIDs). Cox 2 selective inhibitors should be used in cases of long–term use to avoid gastrointestinal problems. Although opioids may be applied in cases in which NSAIDs have no effect, attention should be paid to potential side effects such as nausea and consti-pation, abuse and addiction. Physical therapy including muscle stretching and strengthening is a very important therapeutic modality for chronic noci-ceptive pain. Surgical treatment, such as arthroplasty and spinal fusion, may also be applied in cases in which conservative treatments fail.
As NSAIDs are not effective for neuropathic pain caused by disorders and diseases of nervous system, pregabalin (Ca2+ channel blocker), anti–depressant s and opioids may be applied. Surgery intervention, including laminectomy, discectomy or neurolysis for the purpose of nerve decompres-sion, may be applied in cases in which conservative treatment fail or nerve palsy is observed. For difficult chronic pain cases with psycho–social factors, a multidisciplinary approach including cognitive behavioral therapy should be considered.