Mastering a $110,000 Mechanical Arm

Excerpt: On 11/26/12, James Dao of The New York Times reported on Cpl. Sebastian Gallegos of the Marines who is among a small group of upper limb amputees who have had a pioneering surgery, known as targeted muscle reinnervation, that amplifies nerve signals that control prosthetic arms. He wears a $110,000 robotic device with an electronic motor and sensors able to read signals from his brain. 

Of the more than 1,570 American service members who have had arms, legs, feet or hands amputated because of injuries in Afghanistan or Iraq, fewer than 280 have lost upper limbs. Their struggles to use prosthetic limbs are in many ways far greater than for those who have lost lower-limbs.

With myriad bones, joints and ranges of motion, the upper limbs are among the body’s most complex tools. Replicating their actions with robotic arms can be excruciatingly difficult, requiring amputees to understand the distinct muscle contractions involved in movements they once did without thinking.

Upper limb amputees must also cope with the critical loss of sensation. Touch, the ability to differentiate baby skin from sandpaper or to calibrate between gripping a hammer and clasping a hand, no longer exists.

For all those reasons, nearly half of upper limb amputees choose not to use prostheses, functioning instead with one good arm. By contrast, almost all lower limb amputees use prosthetic legs.

Further information is in the complete NY Times article.