The Case of Phantom Limb Pain
The cover story of The Atlantic Monthly in 1866 was “The Case of George Dedlow,” a story about one of the many individuals who suffered great loss after the Civil War. In the story, Dedlow loses all four limbs through battle and infection, and he is sent to the Philadelphia South Street Hospital, nicknamed the “Stump Hospital” due to the large number of patients with amputations. The story describes how, after his double thigh amputation, he wakes up with a great cramp in both his legs. Although George Dedlow may not have been real, phantom limb pain is a very real, difficult condition faced by many who have undergone amputation surgeries. Many Civil War soldiers experienced very similar conditions. The publishing of this story was monumental in shining light on the phenomenon of phantom limb pain and in improving medical attention provided for patients suffering from it.
Phantom limb pain refers to pain that feels as though it is coming from a part of the body that is no longer there. This pain is fairly common among patients who have unfortunately lost a limb, especially in the legs and arms, with some experiencing it in other regions of the body, such as the breast, eye, and tongue. In fact, most patients who undergo amputations will feel some sort of connection with their missing body part during the first 6 months of recovery. Meanwhile, phantom limb sensation is the sensation some individuals with amputations experience when they have lost a limb feel as though it is still there. Sensations may vary, from feelings of coldness and warmness to itchiness and tangling. Rarely, there are also cases of individuals born without limbs who experience phantom pain as well. An important distinction to make is that phantom limb sensations are different from phantom pain, as phantom pain is, by definition, a pain from a body part that no longer exists.
Phantom pain is reported by many patients as shooting, squeezing, throbbing, or burning. Sometimes, people feel as though their phantom region is being placed in an uncomfortable position, which they are unable to resolve. Phantom pain has its onset in the first few days after operation, can come and go or be continuous, and is often linked to emotional stress. The exact cause of phantom pain is not well defined. MRI and PET scanning reveal certain portions of the brain associated with the nerves of the amputated limb are active as an individual suffers phantom pain, indicating that there is a neural basis to this condition. In the 1990s, there was a vast advancement made in the science of phantom pain, as neuroscientists realized that phantom pain gave great insight into how the motor system works, especially in the field of neural plasticity.
Sam Kean explains this very elegantly in his book, The Tale of the Dueling Neurosurgeons. The brain has somatotopic maps of the regions of the body, and regions of the body that do not require complex motions, for example the legs, cover relatively small cortical area on the brain in comparison to the area of the region on the physical body. When, for example, a hand is amputated, a large part of the somatotopic map in the brain goes dark. However, because of neural plasticity, this spot gets taken over by other neural areas to fully utilize cortical area. Usually, in the case of an amputated hand, the region of the map formerly corresponding to the hand gets taken over by neurons responsible for mapping the face. However, this remapping could cause problems as the new face neural circuits and the old hand neural circuits overlap and intermingle, firing at the same time. This could result in the phenomenon of phantom pain. Touching the face may cause sensation in missing hands for patients who suffer from a hand amputation. Any sensation on the face would cause firing in both the face and hand circuits, bringing up phantom sensations of the hand that no longer exists.
Treatment for phantom pain is very difficult, and no medications specifically for phantom pain exists, though some medication intended for nerve pain prove effective in ameliorating pain. Common medications for treatment include antidepressants, anticonvulsants, narcotics, and NMDA. There are also several noninvasive therapy approaches for phantom pain. Transcutaneous electrical nerve stimulation (TENS) and the mirror box are the most common noninvasive treatments. TENS involves sending a weak electrical current to the area of pain through patches, potentially preventing pain signals from reaching the brain. The mirror box is a less scientific, but nonetheless effective approach. It involves a box with a mirror dividing its interior in two. The box has two openings: one for the intact limb and the other for the stump. The patient would practice performing symmetrical exercises, and from the mirror it would look as though both of his or her arms are intact and moving in sync. There is something about actually perceiving the lost limb in motion that seems to relinquish the phantom from patients’ minds, perhaps due to the brainpower we dedicate to vision compared to our other sensations.
Phantom pain has given neuroscience great insight into the circuitry of the brain’s motor system and into the intricacies of neural plasticity. This knowledge in turn allows for doctors to provide better treatment for individuals who suffer from phantom pain. As more years pass, we may understand the condition even better.