Von Ferber demonstrates his new artificial hand, which he can control using sensors within the device.
The horrors of war have often led to medical benefits in peacetime.
The Civil War spread the use of anesthesia. World War II helped to start the antibiotics revolution.
And now, the Iraq war and its deadly roadside bombs are advancing the development of prosthetics for those who have lost limbs.
So far, the wars in Iraq and Afghanistan have left roughly 1,000 U.S. soldiers with amputations. The vast majority have lost feet and legs, but about 200 soldiers have lost fingers, hands and arms, said Ryan Blanck, upper-extremity specialist at the U.S. Army's Center for the Intrepid in San Antonio, a $65 million facility dedicated to treatment of amputees and burn victims.
The preponderance of leg injuries in the military is related to the nature of improved explosive devices and the injuries they inflict, but it also echoes figures from civilian life.
There are about 130,000 amputations in the United States each year. More than 80 percent involve legs, feet and toes, mostly from circulation problems caused by diabetes.
Finger, hand and arm amputations largely are the results of accidents, and mostly affect young men like those in the military. In addition, children born without hands or arms need prosthetics, said Dr. Joseph Imbriglia of the Wexford, Pa.-based Hand and UpperEx Center.
The Iraq and Afghanistan conflicts have advanced the science of prosthetics by providing an unfortunate pool of amputees whom the government wants to help, Blanck said. Those young men want prosthetics that will allow them to live full, active lives.
Some upper-extremity amputees want to use their prostheses to lift weights. Some want to do push-ups. And some even want prostheses that will allow them to fire weapons, in hopes of going back to a combat zone.
As a result, he said, many soldiers often use both the older harness-style hook prostheses, which provide greater lifting power and are more durable in outdoor weather, and newer myoelectric ones, which are superior for some fine motor movements and operate from electrical signals emitted by the muscles of the person's remaining limb.
The Center for the Intrepid has also become a natural testing bed for prosthetic prototypes, like the new iLimb artificial hands and arms made by Touch Bionics, of Scotland. The iLimb hands permit six separate movements, one for each digit and another for the wrist, said spokesman Phil Newman.
For soldiers with below-the-elbow amputations, the commercial models of the iLimb use two contact points on the inside of a sleeve that fits over the remaining limb. One permits the user to open the hand, the other to close it.
But the Army is experimenting with models that have four or more contact points to try to improve the user's control over individual digits, Blanck said. The center is also experimenting with new medical procedures, he said.
One of the most intriguing is reinnervation, which implants nerves that used to serve a missing limb in new muscles of the upper arm or chest, and then uses signals from those muscles to control the prosthesis.
The advantage of this technique, which has been used on a handful of patients around the country, is that electrodes placed over the new nerve junctions can pick up several signals at the same time and control different movements simultaneously, such as a person picking up a hat and putting it on his head.
Other experimental devices are partial-hand prosthetics for soldiers who have lost some of their fingers. These can be fit over the remaining hand like a glove. Sensors on the inside then can pick up signals from the muscles to control individual prosthetic fingers.
One other improvement in prosthetic hands is not being driven by the military, said Imbriglia: purely aesthetic hands and fingers that are made to look as lifelike as possible.
One of the leading companies is the Parisian firm of Pillet Hand Prosthetics, he said, which makes periodic visits to different U.S. cities to match people's skin and bone structure to new prosthetics that can be customized right down to the freckles.
Another is Livingskin, a company recently acquired by Touch Bionics, which makes lifelike coverings for prosthetics. It even offers a solution that can be used to mimic tanned skin in the summer.
Aesthetic prostheses are not there to improve their user's function, Newman said, but so that "somebody who wants to go to a wedding can do that and not be noticed."