Limbs are amazing and complex things, especially in terms of the way our brain communicates with them. Unlike some animals, we humans can’t simply regrow a limb if we lose it. What’s more, our body’s control systems can become seriously confused. Take the phenomenon of phantom limb pain, which is often experienced by amputees.
People who have lost a limb frequently have some sensation that the limb is still there and a majority of amputees will also experience phantom limb pain, which can manifest itself as an insatiable itch or a stabbing or niggling pain. Although the exact cause is unknown, current thinking is that nerves in the severed limb continue to communicate with the brain, which interprets the mismatch as pain and discomfort.
Now, doctors have devised a new treatment using computer-generated augmented reality. This allows the patient to see and move a virtual arm controlled by their stump. Electric signals, from the muscles in the amputated limb, communicate with the computer, enabling movement in real time. The treatment has alleviated phantom limb pain for amputees after several weeks of the new therapy.
Max Ortiz Catalan, who has pioneered the new treatment, explains what he thinks is going on: "The motor areas in the brain, needed for movement of the amputated arm, are reactivated and the patient obtains visual feedback that tricks the brain into believing there is an arm executing such motor commands. He experiences himself as a whole, with the amputated arm back in place."
Reattaching severed limbs
Meanwhile, there have been several recent instances of surgeons being able to keep a limb alive by reattaching it to another part of the body in order to maintain blood flow. Last August, in an operation that is thought to be the first of its kind, surgeons in the UK removed a large aggressive tumour that had spread from a man’s pelvis into his thigh. In a complex single operation, they then rebuilt his body using leg muscles and tissue they had removed and attached to his arm to keep alive. The 18-hour operation, on Ian McGregor, involved taking his calf, attaching it to his arm and then using it to repair the site of the operation.
Doctors in China have also saved a man's severed hand by grafting it to his ankle, according to reports. The man lost his right hand in an accident at work but could not have it immediately reattached because of damage to his arm. Instead, the hand was kept alive by stitching it to the patient’s left ankle and connecting to the blood supply from arteries in the leg. A month later, surgeons were able to remove the hand and replant it back on his arm.
Unfortunately, replantations are not always successful. Some patients may later opt for amputation because of side-effects, such as pain and stiffness.