When he was 13, Dr. Randy Davis broke his leg and had to wear a cast for six months.

It was an inconvenience for an active teenage boy, but it ended up determining his entire career path.

"I thought, there has to be a better way to do this," said Davis, an orthopedic surgeon and medical director of the Spine and Pain Center at Baltimore Washington Medical Center.

Davis, 55, has spent his 30-year career trying to find that better way.

His research on the cervical spine - the part of the spine that runs through the neck - has led him to develop an artificial cervical disc that helps patients retain motion in their...