597Review Article Neuropathic Pain: Mechanisms and Treatments

Neuropathic pain is caused by functional abnormalities of structur-al lesions in the peripheral or central nervous system, and occurs with-out peripheral nociceptor stimulation. Many common diseases, such as postherpetic neuralgia, trigeminal neuralgia, diabetic neuropathy, spinal cord injury, cancer, stroke, and degenerative neurological diseases may produce neuropathic pain. Recently, theories have been proposed that state there are specific cellular and molecular changes that affect mem-brane excitability and induce new gene expression after nerve injury, thereby allowing for enhanced responses to future stimulation. In addi-tion, the ectopic impulses of neuroma, changes of sodium and calcium channels in injured nerves, sympathetic activation, and deficient central inhibitory pathway contribute to the mechanisms of neuropathic pain. Currently, treatment of neuropathic pain is still a challenge. Pharmacotherapies (antidepressants, antiepileptics) remain the basis of neuropathic pain management. However, patient satisfaction in th