Chris Muir's Day By Day

Tuesday, March 20, 2012

The Infancy of Bionics

A soldier who lost an arm in Afghanistan is now a guinea pig in the field of bionics, a term familiar to those of us who remember the 1970's and The Six Million Dollar Man and The Bionic Woman.

On the night of November 1, 2008, Iraqi insurgents lobbed two RKG-3 armor-piercing hand grenades at an up-armored Humvee in Baghdad. The first grenade, a dud, bounced off the passenger-side door. But the second one detonated, sending a jet of molten copper through the door and through the right elbow of Sergeant First Class Glen Lehman. The liquid metal continued across Lehman’s lap, burning his right thigh, and then sluiced across his left forearm.

Usually a veteran like Lehman would get a prosthetic arm, and life, with luck, would go on. But Lehman’s stump was the right shape for an experimental surgery called targeted muscle reinnervation. He was game to try it, in return for access to a remarkable new prosthetic arm.

Lehman’s surgeons delicately pulled apart the nerves in his arm that would ordinarily control his elbow and hand and moved them. His distal radial nerve, which controls opening the hand, went to the lateral head of his triceps. His median nerve, which controls closing the hand, went to the medial head of the biceps.

It’s a weird surgery with weird effects; Lehman’s skin ripples when he thinks about moving his missing right arm, a physical reminder of the signals his brain is sending. When he tries to close his hand, his biceps contracts. The rerouted nerves are supposed to improve control of a new prosthesis, one that uses a computer to read the myoelectric impulses that are produced by the tiny neural zaps inside muscles. In short, when Lehman is wearing the new arm, he is a cyborg. But being a cyborg has not turned out the way science fiction promised.


Click the link to read the rest. Sadly, it's only the never-ending wars that the US is fighting these days that allows this work to proceed, by supplying an increasing number of amputees.

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