Abstract

Almost all patients who undergo amputation experience the often painful and distressing sensation that the absent body part is still present. The cause of this phenomenon is not fully understood, but it is thought to be mediated in large part at the spinal cord level. Congenitally absent limbs do not seem to be subject to the same phenomenon. Patients may be able to describe the limb in vivid detail, although it is often distorted or in an abnormal position. In many patients, the sensation of the phantom limb fades with time, but in some patients, phantom pain remains a distressing part of daily life. Phantom limb pain is often described as a constant, unpleasant, dysesthetic pain that may be exacerbated by movement or stimulation of the affected cutaneous regions; a sharp, shooting neuritic pain may be superimposed on the constant dysesthetic symptoms, and some patients also note a burning component reminiscent of reflex sympathetic dystrophy. Some investigators reported that severe limb pain before amputation increases the incidence of phantom limb pain, but other investigators failed to find this correlation. Phantom limb pain can take multiple forms, but it usually consists of dysesthetic pain. Additionally, patients may experience abnormal kinesthetic sensations (i.e., that the limb is in an abnormal position) or abnormal kinetic sensations (i.e., that the limb is moving). Investigators have reported that many patients with phantom limb pain experience a telescoping phenomenon; for example, a patient may report that the phantom foot feels like it is attached directly to the proximal thigh. Phantom limb pain may fade over time, and younger patients are more likely to experience this diminution in symptoms. Because of the unusual nature of phantom limb pain, a behavioral component is invariably present.