The Wounds of War
Military investments spur medical advances to restore some of what modern-day warfare has stolen from soldiers
Army veteran Joseph Gross uses a variety of prosthetics to remain active after a bombing in Iraq tore off his right leg.
It was March 2003, and Staff Sgt. Joseph Gross had just 10 days left in the Army. Then his division received combat orders for Iraq. For Gross, there was no question—he was in. "I'd trained so long—it's kind of like training for the Super Bowl and then not going," says Gross. "That's what I was in there for—to do those missions. Ten days or a year left, it didn't really matter, I wanted to go." So he reenlisted for another three years.
Gross completed his first tour in Iraq and came home unharmed. Then, in September 2005, on his second deployment, Gross's squad was doing routine security formations looking for suicide car bombs on the streets of Baghdad. In an instant, two bombs exploded around him. One hit the Humvee that Gross was driving, slicing the truck in half. He remembers flying through the air, then hitting the ground. Instinctively, he began patting himself down, just the way he'd been trained to do. All was well until he reached his legs and looked down. His right leg, from a few inches below the knee, was virtually gone, hanging on only by the inseam of his pants.
Thirty days later, Gross stepped into his new prosthetic leg. A year and a half later, he backpacked the Grand Canyon. Gross, 34, now sports a running leg, a cycling leg, a golfing leg and even a rock-climbing leg, all engineered at the new prosthetics lab at the Louis Stokes Cleveland VA Medical Center. "You go in and you have no idea what kind of foot you're going to put on," says Gross. "They have shelves of different feet to try out. Some bend this way, some that way, some have shock absorbers." Soon, he hopes to be the proud owner of an iWalk, a bionic leg and foot that mimics a real limb.
A decade ago, choices like these wouldn't have been available to Gross and other veterans. The wars in Iraq and Afghanistan have spurred ambitious advances in the rehabilitation and quality of life for soldiers and veterans injured in combat, particularly in the areas of amputations, spinal cord injuries and traumatic brain injuries (TBI). And researchers at Case Western Reserve University School of Medicine, the biomedical engineering department and the Cleveland VA are spearheading many of these advances.
Restoring essential functions of lost limbs
The U.S. Department of Defense (DOD) and the Defense Advanced Research Project Agency (DARPA), an arm of the DOD, have poured tens of millions of dollars into these research initiatives. One example is the Revolutionizing Prosthetics Program, which DARPA introduced five years ago with the aim of creating life-like upper limbs. "Unfortunate as it may be, most prosthetic technology really advances during wartime," says Dustin Tyler, PhD, associate professor of biomedical engineering and associate director of the Cleveland Advanced Platform Technology (APT) Center of Excellence at the Cleveland VA. Prior to the recent push, upper-limb prosthetics hadn't advanced much past the traditional prosthetic hook in many years, says Tyler, who focuses on neural prosthetics for upper-limb amputations. He currently has two DARPA grants and one from the Veterans Affairs Rehabilitation Research and Development division for peripheral nerve stimulation research.
Since the Iraq War began, nearly 1,200 military personnel have been faced with the loss of an arm, hand, leg or foot. A quarter of those include multiple amputations. In the general population in the United States, approximately 1.7 million people live with limb loss, according to the National Limb Loss Information Center—the majority the result of problems with blood flow due to vascular disease, particularly associated with diabetes.
Prosthetic legs still have a long way to go, Tyler notes, but they are well ahead of upper-limb prosthetics. Walking involves a fairly uniform pattern, whereas arm and hand movement involves more detailed, intimate motions. One of the limitations of currently available prosthetic arms and hands, he explains, is that they lack the life-like sensation that we take for granted with the human hand.
As a result, says Robert Kirsch, PhD, people tend to get a prosthetic arm and not use it. "They'll just leave it in the closet," says Kirsch, who is a professor of biomedical engineering and a researcher at the Cleveland Functional Electrical Stimulation (FES) Center, a consortium of the Cleveland VA, Case Western Reserve and MetroHealth Medical Center. Kirsch has a $1.1-million grant from the DOD for research on a prosthetic arm control device for amputees, and he focuses on developing control algorithms that will provide simultaneous control of many different motions of prosthetic arms.
Another drawback of prosthetic arms is that they are mechanically driven: with natural arms, we simply think about the glass of water that we want to reach for, and thousands of wires—our nerves—carry the messages down to our fingers to make that movement happen. But when the arm is amputated, those wires and the signals they convey are cut.
Tyler is working to restore that connection for people with prosthetic arms and to make the artificial hand 'feel' like a real hand. By placing pressure sensors in the artificial fingertips and applying electrical currents to stimulate the nerves, he hopes to restore the signals that travel along the nerve cells, allowing someone with an artificial arm to feel the sensation. "The brain interprets it as your finger tip, even if you don't have a finger tip there," says Tyler.
Tyler and his colleagues have filed an application for their neural interfacing technology with the U.S. FDA and hope to begin preliminary trials in humans in the near future. "We're excited because one of the advantages of Case Western Reserve, the VA and the medical school is that we are well set up to do things from fundamental technology development through application," says Tyler. "We're hoping to make it real here very soon."
The same neural technology could be applied to the lower limbs, says Tyler. Traditional prosthetic legs do well on level surfaces, such as a smooth sidewalk. But when the person wearing them reaches a small incline or bumps into a rock, the prosthetic leg cannot sense those changes and make the necessary adjustments. Therefore, Tyler hopes to one day apply the sensor technology to feet.
Other researchers are also developing similar neural interfacing technologies for the lower limbs, the head and neck, as well as for those who have suffered spinal cord injuries or strokes. Much of this work takes place at the APT and FES centers.
While Tyler focuses on restoring sensations so that a patient can 'feel' his or her prosthetic hand, other researchers at the university are working to improve mobility of prosthetic arms and hands. Hunter Peckham, PhD, professor of biomedical engineering at the university and director of the FES Center, is a pioneer in the field of neural prosthetics. Peckham and his colleagues are restoring upper-limb functions such as hand grasping to those who have suffered spinal cord injuries or stroke.
Gaining independence after a spinal cord injury
In 1995, an off-duty accident left Air Force veteran Chris Wynn paralyzed from the neck down.
In 1993, Chris Wynn was stationed in the Air Force in Hawaii when an off-duty accident left him paralyzed from the neck down at the age of 22. During a Saturday cookout at the beach, Wynn was doing front-flips into the waves when he accidentally landed on his head in shallow water. The impact bent his spinal cord severely. "Instantly I couldn't move," says Wynn. After surgery, Wynn was flown to Cleveland for rehabilitation. Wynn now has limited use of his arms. In 1995, he received one of the first implantable devices, with eight electrical channels, which gives him two hand grasps.
When a person is paralyzed from a spinal cord injury, the central connection between the brain and other body parts is severed. So neural pulses that carry instructions from the brain, such as to pick up your hand to wave hello or to get up off the sofa, cannot cross the damaged region. As a result, a person with paraplegia is usually confined to a wheelchair and has only crude control over his or her hand, wrist and finger movements. "There's really no good way for people to control all of those different motions in a natural way, in a simultaneous way, like you or I would do with our own arm," says Kirsch.
FES Center researchers like Peckham and Kirsch are working to make it possible for people with paralysis to have much more sophisticated arm, hand and wrist control and eventually to even walk up and down a flight of steps. By implanting electrical devices about the size of a Bic lighter in the chest of a person who is paralyzed, researchers can supply an electrical signal that stimulates the muscles to move, "sort of like a gas pedal in a car," says Peckham, whose work focuses on those with hand paralysis.
Devices like those currently being developed by Case Western Reserve researchers would allow a patient like Wynn to extend his fingers and activate his triceps to lift his arms over his head such as to reach a shelf or cabinet. "If I had tricep function, I'd have a whole different level of independence," says Wynn, who is now 41. "I would be able to transfer myself from my chair into bed and things like that without needing as much help."
Ronald Triolo, PhD, professor of orthopaedics and biomedical engineering and executive director of the APT Center, who received a $1.7-million grant from the DOD for his research to improve mobility in people paralyzed from spinal cord injuries, is also working to improve rehabilitation for those with spinal cord injuries by focusing on braces (orthotics) that allow for more natural movements. The CDC estimates that each year between 12,000 and 20,000 people in the general population suffer a spinal cord injury—nearly half of which occur in car accidents. The Department of Veterans Affairs estimates that about 17 percent of all patients in the United States with serious spinal cord injuries and disorders are veterans. Conventional braces restrict movement because they lock the hips, knees and ankles into position. So when a person takes a step, the effect is "sort of like a pair of scissors," says Triolo. "The problem is that kind of walking takes a lot of energy, so it's inefficient, and it's counterintuitive." Triolo is developing a brace that unlocks the joints so that the wearer can take longer steps or even step up onto a curb or stair.
"Because the military invested in this, I think we've really advanced the state of the art in orthotics and brought together new concepts in robotics with older notions in bracing," says Triolo. "Nothing like this has existed before."
Unraveling the complications of traumatic brain injuries
26-year old Army veteran Margaux Vair suffered a traumatic brain injury while patroling in Iraq.
Margaux Vair, a 26-year-old Army veteran, was doing routine patrols with the Iraqi military police in December 2006 when an improvised explosive device (IED) struck her Humvee. She suffered a severe concussion, but with no other apparent symptoms, she continued on with her daily work. It wasn't until three months later, after she suffered a post-traumatic stress event and developed Bell's palsy—a dysfunction of a cranial nerve—that doctors discovered she had a severe brain injury from the blast. More than four years later, Vair still suffers from exhaustion and headaches and has not been able to work. "I have really hard days where I'm sitting on the couch and I'm not doing anything," says Vair. "Then I have good days where I want to go out and walk the dogs or ... go out and plant some flowers. But it's all a roller coaster."
TBIs are so common, particularly as a result of blast injuries, that they are called the "signature wound" of the Iraq War. Some 30 percent of soldiers who were admitted to Walter Reed Army Medical Center since 2003 have been diagnosed with a TBI. Yet despite the prevalence, "we know very little about the neurological consequences of these mild blast injuries and why these soldiers and vets have the persistent syndromes that they do," says Mark Walker, MD, associate professor of neurology at the School of Medicine and staff neurologist at the Cleveland VA and at University Hospitals Case Medical Center. Walker has a DOD grant to investigate disequilibrium after TBI.
Researchers are still working to unravel the complexities of the basic science behind these brain injuries. In the general population, some 1.7 million people sustain a TBI each year, according to the CDC. The leading causes of TBIs in civilians are falls and car crashes. About 75 percent of TBIs are mild and include concussions, but some 52,000 people die each year from a TBI. Even in seemingly mild TBI cases, some people suffer from persistent symptoms such as headaches, balance problems, light sensitivity, vision impairments and mild cognitive impairments such as concentration problems. They also often have trouble sleeping. These symptoms make it very difficult for soldiers or veterans to perform on the job or to function well in everyday life. Yet in routine medical exams, it is difficult to pinpoint the source of the problem, so the complaints are often dismissed. And researchers strongly debate to what degree these problems are physical versus psychological.
Sometimes, though, the physical consequences of a TBI are impossible to ignore. Janis Daly, PhD, professor of neurology at the School of Medicine and director of the cognitive and motor learning research program at the VA, is working to restore lost upper-limb function and gait recovery to those who have suffered TBIs and stroke. Daly has a grant from the DOD to study a new comprehensive treatment strategy to help people with TBIs reintegrate into daily life through cognitive and motor training. Each of the participants in Daly's program has achieved significant milestones that have allowed them to become more involved with their families and communities, she says. Daly is also studying brain plasticity and "brain training" so that TBI and stroke survivors can regain cognitive abilities and motor skills.