Well over half of all amputees report sensations in their missing limbs, including heat, drafts, the touch of a watch or ring -- and pain. Centuries ago, most doctors were certain these sensations were imaginings induced by the mental trauma of losing a limb. A handful of doctors, however, were prescient enough to suggest otherwise.
French military surgeon Ambroise Pare had ample time to study amputees during his country's 16th century religious wars. He surgically removed countless limbs and designed sophisticated prosthetics, replete with springs, gears and joints. Pare noted that soldiers coming in for surgery would often insist that they felt pinpricks in their dead extremities -- a phenomenon he worried would stop other doctors from performing crucial amputations. He also noticed that the phenomenon continued after surgery, "many months after the cutting away of the leg."
Pare, like French philosopher Rene Descartes after him, blamed this strange occurrence on the brain's miscommunication with the body.
Throughout the 1700s and into the early 1800s, more than a few medical dissertations were written on the subject of pain in missing limbs. German scientist Johannes Muller noted that the pain could last decades and be affected by the weather. Scottish doctor Charles Bell provoked the sensations by stimulating amputees' stumps and concluded this was evidence of a sixth sense: the muscle sense.
During the Civil War, American physician Silas Weir Mitchell worked in a Philadelphia hospital for soldiers with nerve injuries and spent much time interviewing amputees at the city's nearby "Stump Hospital."
His observations there led him to write a short story on the plight of an amputee, "The Case of George Dedlow." In it, the hospitalized Dedlow asks an attendant to rub his aching calf; the attendant lifts the bedsheets to show a shocked Dedlow that both calves are gone.
Mitchell later wrote, in a nonfiction account, of the patients at Stump Hospital and their "phantom limbs," putting the term in print for the first time in 1871. He told of men who tried to rein their horses with missing hands and men who attempted to hit other men with fists that were not there.
Doctors have been testing an arsenal of treatments for phantom limb pain since Mitchell's day, including surgery, painkillers and electrically stimulating the brain -- all of which can offer temporary relief, at best.
Part of the problem is that competing theories abound as to the causes. Researchers have implicated abnormal nerve growth; nodules forming at the end of severed nerves; the brain's confusion over the loss of sensory information it once received; and the faulty rewiring of nerves sending signals from the lost limb.
But most researchers now agree that the sensations have physical origins, not psychological ones. Yet many patients are told today what they would have been told in Pare's time -- that the feeling is all in their heads.