The neurological basis and mechanisms for phantom limb pain are all derived from experimental theories and observations. Little is known about the true mechanism causing phantom pains, and many theories highly overlap. Historically, phantom pains were thought to originate from neuromas located at the stump tip. Traumatic neuromas, or non-tumor nerve injuries, often arise from surgeries and result from the abnormal growth of injured nerve fibers. Although stump neuromas contribute to phantom pains, they are not the sole cause. This is because patients with congenital limb deficiency can sometimes, although rarely, experience phantom pains. This suggests that there is a central representation of the limb responsible for painful sensations. Currently, theories are based on altered neurological pathways and cortical reorganization. Although they are highly intertwined, mechanisms are often separated into peripheral, spinal, and central mechanisms.
Almost immediately following the amputation of a limb, 90-98% of patients report experiencing a phantom sensation. Nearly 75% of individuals experience the phantom as soon as anesthesia wears off, and the remaining 25% of patients experience phantoms within a few days or weeks. Of those experiencing innocuous sensations, a majority of patients also report distinct painful sensations.