Tuesday, February 2, 2010
Phantom limb pains are a common and difficult problem after amputations—even though the injured limb is removed, the pain continues. "The pain pathways in the spinal cord and brain 'remember' the painful injury," says Dr. Shafer. "Because of this memory, the missing arm or leg continues to ache, sometimes severely so, long after the limb itself has been amputated."
Dr. Hanling and colleagues used mirror therapy in an attempt to prevent phantom pain in four soldiers requiring leg amputation because of combat injuries. In each case, amputation was necessary after extensive efforts to save the leg.
Before amputation surgery, the patients performed several sessions of mirror therapy. "In this form of therapy, patients sit with a mirror placed vertically between the legs and arms so that they are reflected in it," Dr. Shafer explains. The reflection in the mirror makes it look like the injured arm or leg is healthy and normal.
"Patients then observe and control their injured arm or leg in the mirror—but they are actually observing and controlling the reflected uninjured arm or leg," says Dr. Shafer. "The brain and spinal cord are visually tricked into believing that all of the arms and legs are intact and without pain."
None of the four soldiers had major problems with phantom pain after amputation. Any episodes of phantom limb pain were brief and mild. Importantly, all patients were able to fully participate in their postoperative physical therapy program.
Mirror therapy appears to re-program the brain's pain circuits into thinking that the painful injury is no longer present, according to Dr. Shafer. "Removing the source of the pain may not let the brain forget this memory, but by controlling, seeing, and reacting to a healthy limb, the brain can be tricked into believing the limb has healed, reducing the risk of phantom limb pain when the injured limb is eventually amputated."
Previous studies have reported the use of mirror therapy in patients with phantom pain that does not respond to other treatments. Although more research is needed, the new results suggest that mirror therapy performed before amputation may prevent disabling phantom limb pain from developing in the first place.
Read the full study in Anesthesia & Analgesia