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Advances in Prosthetics and 3D Printing Transform Life for the Disabled

3 Dec 2015 by Teresa Meek

December 3 is Disability Day, giving us a chance to celebrate the truly remarkable advances science is making with prosthetics.

In the past, if you had the misfortune of losing your arm or hand or foot, you were out of luck. You could get an artificial limb, but it didn’t do anything — at least, not until the 20th century. And it didn’t take away the terrible phantom pain experienced by many amputees.

In the late 1960s, scientists developed prosthetics controlled by muscle impulses, but the technology was difficult to operate, imprecise and frustrating for users.

Fast-forward to today, and microprocessors, computer chips and robotics are radically changing the experience of amputees, making artificial limbs easier to use and much more natural.

Bionic limbs that feel

Last year, an international team of scientists created a bionic hand that not only moves and functions normally — it feels.

Sensors in an artificial hand tested on a patient collected information about shape and pressure of objects the hand encountered. It relayed the information to electrodes implanted in the patient’s upper arm, which in turn sent it to his brain. The blindfolded patient was able to sense whether objects were soft or hard, and square or round.

The hand is still in prototype phase, and scientists are currently working to develop additional sensors to sense texture and temperature.

This year, another group of scientists created an artificial leg that allowed a man to feel lifelike sensations in a prosthetic foot. Similar to the bionic hand, it uses sensors in the foot to measure movement and pressure in the heel and toe, sending the information to a micro-controller that relays them to sensors in the stump of the man’s old limb, which in turn sends them to his brain.

The man, who is able to run, cycle and climb, can feel whether the surface he trods is concrete, gravel or sand. He no longer slips on ice.

Perhaps best of all, the excruciating phantom pain he had felt since his amputation years earlier has greatly diminished.

Effortless control

Also this year, Icelandic company Össur successfully tested an even more science-fiction-like development: a prosthetic limb that is controlled by subconscious thought.

The system was tested in a patient who had lost his foot. Implanted MyoElectric Sensors (IMES) were embedded in the muscle tissue of his stump. The sensors connected wirelessly to a computer in the “smart” artificial foot, enabling the foot to adjust itself to the man’s gait and terrain he walks on. When he wants to stand up or walk, his foot adjusts itself as it normally would without his having to concentrate or “tell” it what to do.

Incremental improvements

While these and other cutting-edge prototypes are exciting, it will be years before they are able to help disabled people on a large scale. In the meantime, medical practitioners are finding broader applications for existing technology.

For example, retinal implants have been around for years, but until recently, they only helped people with a rare type of eye disease.

This year, British surgeons successfully performed a retinal implant in a man with macular degeneration, a common vision-deteriorating condition among older people.

The "bionic eye" received visual information from a tiny camera mounted on the patient’s glasses, translating it into electrical impulses that were sent wirelessly to the retina, which relayed them to the brain. As a result, the patient was able to see patterns of horizontal, vertical and diagonal lines on a computer screen — patterns that he couldn’t distinguish before.

The sea change of 3D printing

Prosthetics have come a long way, but they are complicated to build and cost thousands of dollars, putting them out of reach for many people. This is especially true for children, whose limbs have to be replaced many times as they grow. Most of them simply do without.

But the advent of 3D printing is changing that picture.

3D printers can create prosthetics much more cheaply — the materials for a 3D-printed prosthetic hand can cost as little as $20-50, and some experts say they work just as well as expensive versions.

These artificial limbs don’t look like the real thing — their brightly-colored plastic contours instead suggest the appendages of comic book or videogame superheroes — and that’s just fine with the kids who use them.

An artificial, 3D-printed hand may not be able to feel, but it moves, grasps and functions like a normal hand.

It doesn’t take an orthopedist to fit 3D prosthetics, either. Patients (or their parents) can input measurements into an online tool to generate files for 3D printing.

Johns Hopkins Hospital recently purchased a 3D printer to create free prosthetics for children.

From kids to kids

In fact, 3D printing is so simple, a child could do it.

And three sixth-graders in South Carolina are doing just that through Enabling the Future, an organization that connects people who own 3D printers with people who need prosthetics. After a few stumbles, the girls successfully printed a new hand for an 11-year-old and presented it to her in an emotional ceremony.

3D printing is also helping speed new limbs to amputees in Uganda, where medical workers have an average waiting list of 5,000.

It took centuries for prosthetics to become functional. Thanks to wireless sensors and microprocessors, they will soon not only work, but feel like the real thing — at a price anyone can afford.