Phantom limb pain. Mechanism-based management.

Clinically significant phantom limb pain occurs among a large minority of amputees. Most suffer at least occasional episodes. It is becoming increasingly apparent that although psychological factors are not important in the cause of phantom pain, a variety of physiologic problems related to the residual limb are critical to it. Referred pain, initiated by decreased blood flow and microspasms in the residual limb along with problems caused by prosthetics account for most of the phantom pain problems seen clinically. Some pain is referred to the phantom pain from other sites in the body such as the back. Treatments for phantom pain that are not based on recently elucidated physiologic mechanisms have proven to be ineffective for the vast majority and cannot be applied indiscriminantly with any hope of consistent success. Mechanism-based treatments related to specific symptoms can be effective when used appropriately. They include the use of peripheral vasodilators, muscle relaxants, and biofeedback to correct specific problems with blood flow and muscle tension in the residual limb.