Pathogenesis and mechanisms of phantom pain

Although phantom limb pain is a well-known syndrome, phantom sensation or pain may affect virtually any part of the body (somatic or visceral) that is accessible to sensory perception. This review begins with a novel classification system of this diverse group of clinical conditions. Attention is then devoted to the mechanisms responsible for the pathogenesis of phantom pain, notably, deafferentation and nerve injury. The mechanisms of how regional anesthesia may prevent, or sometimes reactivate, phantom pain are discussed. Finally, a consideration is given to the various theories and models that have evolved to explain phantom phenomena, with particular emphasis on the “neuromatrix paradigm.”