Going out on a limb

Stand up. Step forward. Bend an elbow. Button your shirt. Feed yourself. They are simple commands, carried from the brain to the legs, arms, and hands by thin white fibers, nerves no thicker than a piece of yarn, impossibly delicate yet incredibly important. Cut them, break them, shred them--a car crash or a sharp piece of broken glass will do it--and a limb hangs helpless.

Don't count on most orthopedic surgeons for help--they'll fix broken bones but not broken nerves. Neurosurgeons? They like to work on the brain and spinal cord. "Peripheral nerves, the ones in the extremities, are orphans in medicine," says Susan Mackinnon, chief of plastic and reconstructive surgery at the School of Medicine at Washington University in St. Louis. "A lot of specialists dabble, but nerves belong to no one."

Actually, they belong to Mackinnon. The 56-year-old surgeon performed the first nerve transplant in 1988, using nerves from a cadaver to restore feeling and movement to a boy's crippled leg, and has devoted her career to nerve repair. It's a huge problem: There are an estimated 360,000 nerve injuries to arms, hands, and shoulders every year, from car and motorcycle accidents, mishaps with power tools and lawnmowers, and even from surgeons setting bones who get a little too close to the vital fibers. (Numbers on leg and foot injuries are not as firm, but doctors think it's well over 100,000.) Often, surgeons recommend amputation to patients with dangling limbs. Yet Mackinnon has worked out ways of not just transplanting nerves from a donor but also rerouting a patient's own healthy nerves into areas left paralyzed by damaged ones. "I can simply take one of their own nerves and move it a little bit to a new place, and let the brain do the rest," she says.

There are now fewer than a dozen surgeons in the United States who mend nerves in this fashion, and "Mackinnon was certainly one of the pioneers," says Andrew Elkwood, chief of plastic and reconstructive surgery at Monmouth Medical Center in New Jersey, who has done nine donor nerve transplants, building on Mackinnon's work. "She's one of the few people who do all kinds of nerve repair, everything from soup to nuts."

•	Going out on a limb U.S. News & World Report, Monday, May 8, 2006 Byline: Josh Fischman