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Several years ago, Peggy Chenoweth began having excruciating cramping in her ankle. It felt severely sprained and as if her toe were twisting to the point where it was being ripped off her foot.

“The pain is right here,” she told an orthopedic surgeon, “in my ankle and foot.” But the 41-year-old Gainesville, Va., resident no longer had that ankle and foot. Her leg had been amputated below the knee after a large piece of computer equipment fell off a cart, crushed her foot and caused nerve damage. Further, she insisted that since the amputation, she could feel her missing toes move.

Chenoweth’s surgeon knew exactly what was going on: phantom pain.

Lynn Webster, an anesthesiologist and past president of the American Academy of Pain Medicine, explains the phenomenon: “With ‘phantom pain,’ nerves that transmitted information from the brain to the now-missing body part continue to send impulses, which relay the message of pain.”

It feels as if the removed part is still there and hurting, but pain is actually in the brain. The sensation ranges from annoying itching to red-hot burning.

Physicians wrote about phantom pain as early as the 1860s, but U.S. research on this condition has increased recently, spurred by the surge of amputees returning from warfare in Iraq and Afghanistan and by increasing rates of diabetes. (Since 2003, nearly 1,650 service members have lost limbs, according to the Congressional Research Service. In 2010, about 73,000 amputations were performed on diabetics in the United States, according to the Centers for Disease Control and Prevention.)

Of the 2 million Americans living with limb loss, about 90 percent experience phantom pain, according to the Amputee Coalition, an education and advocacy organization.

Medications to relieve this pain have been used for decades, often with limited success. In the past 10 years surgeries have evolved to deaden malfunctioning nerves, and recently these surgeries have been able to target those nerves more precisely. In addition, noninvasive therapies employ exercises to retrain the brain to stop or alter pain signals.

The techniques that are moving most quickly involve electrical brain stimulation, which alters nerve activity, according to James Giordano, professor of Neurology at Georgetown University Medical Center. Hoping to generate a greater response, he says, researchers are combining electrical stimulation with pharmaceuticals and/or a therapy in which patients move their remaining limb while watching it in a mirror.

The effectiveness of all these treatment approaches varies. Some patients report minimal or moderate improvements. Occasionally the pain comes back stronger than before. Some say that therapies profoundly changed their lives for the better.

Most patients start on medication, and early intervention is key, according to Keith Myers, chief of physical medicine at Walter Reed National Military Medical Center in Bethesda.

“Addressing [phantom pain] early may avoid a syndrome where pain centers in the brain become overly sensitive, leading to chronic pain,” he says.

One technique is transcranial magnetic stimulation, or TMS, in which a magnet placed on the patient’s head produces a weak current that travels to the brain’s surface. “This changes activity of nerve cells that correlate with where the amputated limb was,” Giordano says.

A small study published in 2011 found that TMS can produce long-lasting relief from phantom pain.

A similar therapy, which is more targeted and goes deeper into the brain than TMS, sometimes yields better results. In this approach, electrodes implanted in the brain send currents to regions associated with the pain signals. A study involving five amputees found such deep brain stimulation achieved pain relief; the investigators recommended further research to confirm the findings.

A main theory behind phantom pain is that the brain retains memories of pain or sensations felt before or at the time of injury, says Jack Tsao, a neurology professor at the Uniformed Services University of the Health Sciences in Bethesda, a government institution. He formerly ran a traumatic brain injury program at the Navy Bureau of Medicine and Surgery in Falls Church.

“One Marine I saw was firing his machine gun when a grenade took off his hand. He continued to feel like his hand was pulling on the trigger and he could not let go of his gun,” Tsao says.

During the 2005 surge of American forces in Iraq, Walter Reed saw an influx of amputees; although they were on heavy opiates, the drugs did not ease their phantom pain. So Tsao began looking at mirror therapy.

“The brain believes that the missing limb has been restored because in the mirror the existing limb [which they move as they watch in the mirror] appears to be on the opposite side,” Tsao says. “The theory is that by repeatedly visualizing the phantom limb moving, we rewire the brain to turn off overactivation of nerves that we think is triggered by amputation.”

Chenoweth, the amputee from Gainesville, found pain relief with anti-seizure medications that quiet disruptive nerve signals, though she has bad flares occasionally.

“I am lucky I don’t suffer like a lot of people do,” she says.

Phantom pain can also affect a paralyzed part of the body. Robert Salathe, a race-car parts salesman from York, Pa., was beginning to wonder if his searing pain would ever stop. The unbearable burning and stabbing seemed to be in his arm even though it had become paralyzed when he crashed his four-wheel ATV.

“In this injury, the nerves that were torn from the spinal cord and travel to the arm no longer function,” says Allan Belzberg, a Johns Hopkins neurosurgeon. “The remaining nerves, damaged when the arm nerves were torn out, misfire. These misfiring nerves send abnormal signals to the brain interpreted as horrific pain.”

In January, after 10 years in what he calls an opiate-induced fog, Salathe went to Belzberg for surgery.

By that point he’d tried acupuncture, which brought no relief. He’d spent two months in an inpatient pain clinic for medication adjustments and to learn pain management tools such as biofeedback, in which he visualized relaxing images. This moderately lessened the pain, but there were still days when he couldn’t get out of bed.

In a six-hour surgery, Belzberg opened the canal that contains the spinal cord and made precise burns to the injured nerves to deaden them.

“I woke up, and the pain was gone. Completely,” Salathe says, though it took six weeks to fully realize this — once he was weaned off the narcotics. “The fog I’d been in for years was lifting. My memory is better. I’m not sleepy all the time. I am back to work. I got my life back.”

Some of the patients at Adventist HealthCare’s physical health and rehabilitation program in Rockville are diabetics who lost legs because of damage to their blood vessels. Unlike the military people whom Tsao sees, they are on average between 50 and 65 years old and have additional medical problems, such as hypertension and high cholesterol, for which they take drugs.

So there are many factors to juggle in managing their phantom pain, according to Terrence Sheehan, the physician who runs the amputee clinic at Adventist.

Most of his patients improve with anti-seizure medications combined with desensitization techniques, such as getting used to wearing a prosthetic. The prosthesis puts pressure on the remainder of the amputated limb, enabling the brain to recognize it as the end of the existing anatomy, which alters impulses to the missing limb.

But what helps these patients most is a holistic approach, Sheehan says.

“The whole person hurts, which worsens pain. We have trained peer visitors and therapists to work with people on their varied needs,” he says. “But the patients do most of the work. They must acknowledge their loss, work through body-image changes and overall life changes. Then pain often starts to dissipate.”

Karidis is a freelance writer.