Phantom Limb Pain

Phantom limb pain is a chronic pain perceived in an absent limb. The precise incidence has not been determined. Phantom limb sensation occurs in almost all amputees. It must be distinguished from phantom limb pain itself.

There are several hypotheses for the pathophysiology of phantom limb pain: 1) peripheral due to loss of peripheral nerve activity, 2) spinal segmental due to deafferentation effects, 3) central due to changes in the cortex and thalamus, 4) psychologic. In most patients the pain begins shortly after the amputation occurs. Some patients have a spontaneous remission of their symptoms, most often in the first year after injury. The types of pain are also varied. The pain can be continuous or intermittent. The intensity of the pain also varies dramatically. For some it is only an annoyance, and for others the pain is unbearable.

Treatment of phantom limb pain is an urgent problem that should be treated as soon as possible to prevent more permanent plastic changes occurring within the nervous system. Treatments include NSAIDS, narcotics, anticonvulsants, and antidepressants. Many different nerve blocks have been tried. Their effectiveness is based on anecdotal reports. Regional blocks,neuraxial opioids, sympathetic nerve blocks, and dorsal column stimulators have been used with various degrees of effectiveness. It is also important to recognize the importance of psychological and social factors in the overall treatment of these patients.