Innovations in Amputee Care Discussed at Science Café

By Daniel Daglis
National Museum of Health and Medicine

Director of the Brigham and Women's Hospital Lower Extremity Transplant Program and Research Scientist for the MIT Center for Extreme Bionics, Matthew Carty, MD, visited the National Museum of Health and Medicine (NMHM) to speak at the April 26, 2016 Science Café about the recent major innovations in the care of the amputee patient.

According to Carty, there are nearly 600,000 major lower extremity amputations each year. About 20 percent of these amputations are due to some type of trauma; the rest are due to dysvascular problems such as diabetes. Lower extremity amputations are three times as common as upper limb amputations due to the fact that legs are much more exposed and susceptible to injury. The work being done by Carty and his colleagues helps the amputee patient regain a sense of normalcy.

"Whenever there is an impairment suffered by an amputee patient, there are not only significant functional issues, but psychological issues as well," said Carty. "This impairment impedes their ability to interact with the world and be part of the social fabric we have in terms of community and sociability."

Patients can often experience severe pain where their limb once was and they lose proprioception, which refers to the sense of knowing where their limb is in space without visually looking at it.

Wendy Dean, Ph.D., Medical Officer at the U.S. Army's Medical Research and Materiel Command (USAMRMC), said: "Just returning proprioception to our wounded warrior amputees would be of great benefit. Also returning sensation would be a remarkable achievement, which would restore some critical aspects of function not possible today."

Prosthetics and reconstruction are the two most common options when it comes to replacing an appendage. Replantation is another option, but is much rarer. Carty said: "With replantation the sensory recovery for the patient can be quite good. It can take up to 17 or 18 operations to achieve successful replantation."

Carty also pointed out that several victims of the 2013 Boston Marathon bombing underwent limb salvage quite successfully. If a limb cannot be rebuilt, there are other procedures which involve the moving of tendons or nerves, or taking tissue from another part of the body to fill in the defect. However, prosthetics are often used as a common replacement for an amputated appendage.

"The level of function that can be achieved with lower-limb prosthetics is actually quite good. They are customizable and there are various versions. The downside is prosthetics require frequent refitting and the patient does not regain their sense of feeling," Carty said.

"Dr. Carty's research holds promise for improving outcomes of all amputees, but may hold particular promise for those looking to return to very high levels of function, such as military amputees," Dean said. The Armed Forces Institute of Regenerative Medicine (AFIRM), which is managed and funded through USAMRMC, is working to develop advanced treatment options for our severely wounded servicemen and women.

Leg prosthetics, in particular, are closer to replacing the normal function of the original limb. Science Café attendees were shown a video clip of a veteran running on an uneven terrain on grass, which would have been impossible five years ago, according to Carty.

"There has also been exponential advancement in terms of sophistication in electronics in prosthetics," Carty said. "A lot of this has to do with the technology that is in a cell phone. The miniaturization of accelerometers and other various types of microelectronics have made it possible to advance certain robotic prosthetics."

NMHM recently accessioned a "DEKA Arm" into the historical collection of prosthetics that includes a Civil War-era Gildea artificial arm and a prosthetic artificial arm worn by wounded World War II veteran Robert O. Burkhardt. The DEKA Arm is the same size and weight as a natural human arm and was developed by Segway inventor Dean Kamen. The prosthetic senses movement via electrodes and translates those movements into powered motor controls for the device. The DEKA Arm project was funded by the Defense Advanced Research Projects Agency (DARPA), which contributed an example of the device to NMHM.

"Currently," Carty said, "there are prosthetics that are capable of giving info back to the body - bi-directional interactivity - the problem is there is no straight-forward way to connect to the brain." Carty added that the goal is to figure out a way of connecting a prosthetic to the brain so the patient can feel sensations and have seamless movement much like with a natural appendage.

Carty is also optimistic that limb transplantation will be a viable option in the near future. According to Carty, the current setback is the time it takes for nerve regrowth. "Nerves regrow at the rate of a millimeter a day," says Carty. "This means it can take years for the patient to have full functionality and they would require intense physical therapy." Despite the setbacks, in one survey Carty presented, 43 percent of amputee patients showed interest in limb transplantation.

NMHM's Medical Museum Science Cafés are a regular series of informal talks that connect the mission of the Department of Defense museum with the public. NMHM was founded as the Army Medical Museum in 1862 and moved to its current location in Silver Spring, Maryland in 2012. NMHM is an element of the Defense Health Agency. For more information on upcoming events, please call 301-319-3303 or visit www.medicalmuseum.mil.

 

	Caption: Dr. Matthew Carty describes advancements in prosthetics to an audience in the Anatomy and Pathology Gallery of the National Museum of Health and Medicine, in Silver Spring, Maryland, during the April 26, 2016, Medical Museum Science Café. (National Museum of Health and Medicine photo by Matthew Breitbart / Released)
	Caption: Dr. Matthew Carty points to a diagram as he explains Targeted Muscle Reinnervation (TMR), a method of reassigning nerves that once controlled the arm and the hand, at the April 26, 2016, Science Café held at the National Museum of Health and Medicine, in Silver Spring, Maryland. (National Museum of Health and Medicine photo by Matthew Breitbart / Released)
	Caption: Alan Hawk, historical collections manager at the National Museum of Health and Medicine (NMHM), shows the DEKA Arm from the museum's collections to attendees of the April 26, 2016 Science Café held at NMHM in Silver Spring, Maryland. (National Museum of Health and Medicine photo by Matthew Breitbart / Released)