Medicine: Bionic Back

Spine-straightening electricity

For decades, the standard way to straighten out a child's curved spine was with a bulky back brace. Worn for up to eight years, it was not a pleasant prospect for the 25 out of 1,000 American teen-agers (90% girls) afflicted with spinal curvatures, or scoliosis. For those with severe curves, surgery often was required. It too had its unpleasant consequences, sometimes including nine months' confinement in a hip-to-chin plaster body cast.

Over the years, doctors have tried to soften the treatment: braces have gotten smaller, casts lighter. Now, for moderate cases,...