29 November 2018
THURSDAY, Nov. 29, 2018 (HealthDay News) — Climbing enthusiast Jim Ewing lost his left foot in the aftermath of a 50-foot fall off a Cayman Islands cliff. But Ewing is scaling rock walls again with the aid of a robotic ankle and foot he works as well as his former flesh-and-blood version, thanks to a groundbreaking amputation procedure that eliminates the “phantom limb” effect. That’s a disorienting side effect that makes it hard for patients to work their prosthetic limbs properly. This August — a little more than two years after his amputation — Ewing successfully tackled the Lotus Flower Tower, a renowned 8,430-foot peak located in the Northwest Territories of Canada. “When I’m connected to the robotic ankle, I can use it as if it’s my very own,” said Ewing, 54, of Falmouth, Maine. “It’s a very natural transition going from no foot to all of a sudden having my foot back. I don’t have to retrain my brain or retrain my muscles to do anything. It’s pretty much a one-for-one replacement.” Losing a limb causes many disconcerting effects, as the brain tries to interpret signals from an arm or leg that’s no longer there. One of the oddest might be the fact that not only do people feel as though they have a phantom limb, but that limb’s position in their mind often doesn’t match the location of their prosthetic replacement. “They can perceive a foot that is somewhere in space, but oftentimes is disembodied,” said lead researcher Dr. Matthew Carty, director of the Lower Extremity Transplant Program at Brigham and Women’s Hospital in Boston. “It doesn’t map geographically to where their prosthetic foot is. It’s kind of floating to the side, or they may feel it’s encased in a hard block and they can’t move it.” These misleading signals can make it difficult for amputees to learn how to work a prosthetic limb properly. New surgery erases disconnect with prosthetic limb In July 2016, Ewing became the first person to undergo an amputation procedure designed to eliminate this disconnect. Named after him, the Ewing Amputation recreates the normal tug-and-stretch relationship of muscles that occurs during normal movement of legs or arms. When you move a limb, muscles on one side contract while muscles on the other side stretch, Carty explained. For example, when you lift a foot off the ground and move your ankle around, you’ll feel muscles on both sides of your leg moving back and forth. Researchers have learned that as they work, the muscles are sending constant signals to the brain’s proprioceptive sensory system. Proprioception is your ability to know the exact position of your limbs at all times, allowing you to precisely coordinate their movements. “It transmits information back to our brain where the limb is in space without us having to look at it,” Carty said. Traditional amputation screws up these signals by decoupling the muscles, Carty said. The lack of push-and-pull muscle feedback confuses the brain, creating misleading perceptions of a disembodied phantom limb. A Ewing Amputation recreates the push/pull dynamic by surgically connecting muscles that normally operate in pairs, forcing one muscle to stretch in response to the other muscle contracting. Fed the normal muscle signals, the brain is better able to make a person’s perception of their lost limb line up with their new prosthetic, Carty said. “The phantom limb the patient perceives maps geographically over their prosthetic device,” Carty said. “When they think about moving their phantom limb, their brain superimposes that phantom limb over the prosthetic limb.” Amputees also often feel sensations of itching or pain associated with their phantom limb, as the brain struggles to make sense of discordant signals. The Ewing Amputation appears to prevent those sensations, the researchers added. Success with procedure grows Since Ewing, doctors have performed this amputation procedure on 11 more patients, Carty said. Ten lost their leg below the knee, and one lost their leg above the knee. “At this point, we have enough data to say we think we’ve figured out a better way to do amputations, and we’re in the process of testing that in a variety of different clinical scenarios,” Carty said. The research team has received funding to develop the procedure for arm amputation as well, Carty added. Ewing had his climbing accident in December 2014, and at first, the damage to his left ankle was the least of his worries. He had life-threatening injuries throughout his body that required emergency treatment. However, the ankle failed to heal properly during two years of recovery, remaining painful and swollen, Ewing said. A CT scan revealed that most of the bone in the ankle had died. “It was not going to heal and recover,” Ewing said. “It was not likely I would ever regain use of the foot, so I opted to have it amputated.” Carty had been working with a team at MIT to create a robotic limb that would work in conjunction with the new transplant procedure his team had dreamed up. It just so happened that a friend of Ewing is a lead researcher at MIT, who put him in contact with Carty. But special surgery not for every amputee This sequence of events points out one drawback to the new procedure, said Dr. Ageliki Vouyouka, an associate professor of surgery and radiology at the Icahn School of Medicine at Mount Sinai in New York City. The procedure uses tissue harvested from the amputated limb to create the new connections between muscle groups, Vouyouka noted. Given this, people who lose limbs damaged by gangrene, poor blood flow or other diseases that kill off tissue would likely not be good candidates for the Ewing Amputation. But the new procedure is a “very interesting development” that is likely to become a new standard for amputation if further testing bears it out, said Vouyouka, who was not involved with the research. “Mostly I can see that happening for limbs lost to war trauma or civilian trauma,” she said. The new amputation procedure has provided other benefits on top of easier adaptation to his prosthetic foot, Ewing said. “The muscle definition is much stronger. There’s much more tissue there. My leg hasn’t atrophied away to skin and bones, which happens quite a lot with amputations,” Ewing said. “The thinking is the residual limb is healthier because there’s all this active muscle tissue there. You have improved circulation, more muscle tissue for padding and all of that,” he said. The study on Ewing’s case was published recently in the online journal PRS Global Open. More information The Mayo Clinic has more about phantom pain.
27 September 2018
THURSDAY, Sept. 27, 2018 (American Heart Association) — Having a limb amputated can be traumatic, yet experts say not enough is being done to prevent a common disease that can lead to limb loss. Critical limb ischemia, or CLI, is a severe form of peripheral artery disease, a narrowing of the arteries of the extremities that typically affects the legs. At least 6.8 million Americans ages 40 and older have peripheral artery disease. Among them, more than 1 percent develop critical limb ischemia. Critical limb ischemia is caused by the same artery-clogging plaque that causes heart attacks and strokes, said Dr. Mark Creager, director of the Heart and Vascular Center at Dartmouth-Hitchcock Medical Center in New Hampshire. “CLI occurs when the blockages are so severe that the blood supply to the leg — and particularly to the foot — is inadequate to maintain its normal nutritional needs. A patient’s skin might break down and progress to ulcers and gangrene, and they may end up losing their leg,” said Creager, a professor of medicine at Dartmouth. Estimates vary on how many people with CLI go on to have amputations, with one study reporting that without treatment, up to 40 percent of patients have an amputation within one year. Symptoms of CLI include leg and foot pain, infections, and cracks and sores that don’t heal. “Look at your feet. The presence of painful fissures, particularly between the toes, nonhealing ulcers, and blackened toes could each be an indication of CLI,” Creager said. “Another sign of CLI is persistent pain in the feet, oftentimes when the patient is lying in bed, which may improve with standing. We have more blood supply to the foot when we’re standing because of the effects of gravity. If you have more pain in your feet when you put your legs up, that’s a worrisome symptom,” he said. Spotting symptoms early and getting to the doctor quickly is essential, said Dr. Marie Gerhard-Herman, a physician and associate professor of medicine at Harvard Medical School. “Early recognition is huge, because if you can increase blood flow to their foot or leg before the muscle starts dying, then you can actually bring the foot or the leg back to life,” said Gerhard-Herman, who chaired the group that wrote the 2016 peripheral artery disease guidelines from the American Heart Association and the American College of Cardiology. Patients with peripheral artery disease should be treated with cholesterol-lowering statins and blood-thinning medications to reduce the risk of heart attack and prevent CLI, Creager said. Once CLI occurs, patients should be considered for a revascularization procedure that restores blood flow and may involve stents or bypass surgery, he said. Two main risk factors for critical limb ischemia are smoking and diabetes, said Gerhard-Herman. “We know that people who stop smoking have less peripheral artery disease, which means less CLI,” she said. And because people with diabetes are more prone to infections, “if they don’t have enough blood delivered to the limb, they cannot fight the infection, and they lose the limb,” she added, making better diabetes control extremely important. Other lifestyle factors that can help control peripheral artery disease and possibly prevent critical limb ischemia include eating a healthy diet, maintaining normal blood pressure and cholesterol levels, and getting regular exercise. But experts say there are still a lot of unanswered questions about how to best prevent and control critical limb ischemia. “There’s a terrific need for research to develop additional therapies for CLI … there’s a long way to go,” Creager said. “We also have to enlighten the public about CLI so patients can take steps to get PAD identified earlier, get the appropriate treatment, and prevent the risk of progression of CLI and loss of limb.” Eileen Bogosian can vouch for how traumatic the loss of a limb can be. A retired X-ray technician, singer and teacher, Bogosian, 84, developed peripheral artery disease and then critical limb ischemia after she was first diagnosed with a benign bone tumor and bone fractures on her right femur. After going through a series of stent surgeries, Bogosian had her right leg amputated above the knee in June. She said getting early treatment allowed her to keep her leg for several years longer than she otherwise would have, and she urged people to seek medical attention quickly, and reject any advice from friends who say otherwise. “If you are suddenly noticing any questionable symptoms, don’t wait. Waiting is going to possibly add damage to what you already have,” said Bogosian of Seekonk, Massachusetts. “I tell people — especially elderly people — to be your own advocate and get to a doctor. You need to catch it early and nip it in the bud so you can keep living a happy, healthy life.”