For some of the 200,000 people each year who suffer pain severe enough to require lower-back surgery, a new solution has arrived. The Charit Artificial Disc is expected to receive FDA approval for degenerative disc disease by the end of 2004, making it the only artificial spinal disc available in the U.S. “This is the first major breakthrough in back surgery since the 1940s,” says orthopedic surgeon Richard Guyer of the Texas Back Institute in Plano.