Surgeons have used stem cells from fat to help repair skull damage in a 7-year-old girl in Germany, in what's apparently the first time such fat-derived cells have been exploited to grow bone in a human. The girl had been injured two years before in a fall, which destroyed several areas of her skull totaling nearly 19 square inches, the German researchers reported. Other surgeons had failed to correct the defects, and the girl wore a protective helmet. Her brain could sometimes be seen pulsating through the missing areas of her skull. But several weeks after the stem-cell surgery, she...