Mechanisms of phantom limb pain
Phantom pain can occur after amputation of any body part, whether it be postsurgical or traumatic limb amputation or following mastectomy or tooth extraction. The specific pathophysiology that causes phantom pain is not known. Some research suggests that “shrinkage” of the somatosensory cortical representation of an amputated limb correlates with the development of pain. Other research suggests phantom pain is a somatosensory “memory” that involves complex interactions of neural networks in the brain. We do know that phantom pain is rare in congenital amputees or children who lose a limb prior to age 6, suggesting some degree of CNS maturation is required to develop pain. Changes in cortical pain processing accompany phantom limb pain and can be seen with PET or functional MRI scanning.