ATLANTA - Atlanta doctors on Tuesday performed a rare surgery to repair a 2-year-old girl whose liver, stomach and bowels have grown outside her abdomen.

ShaNiya Johnson suffers from a rare birth defect in which the muscles of the abdominal wall did not close properly. The operation is designed to gradually expand a space in her abdomen, and paves the way for a second surgery next month in which doctors will place the organs into the expanded cavity.

ShaNiya is believed to be just the third or fourth child to have the series of operations, which cost an estimated $80,000 to $100,000.

The birth defect was spotted five months into the pregnancy, said ShaNiya's mother, 20-year-old LaTreveon Johnson of Stone Mountain, Ga.

ShaNiya's condition is called an omphalocele. What doctors call a "small" omphalocele, involving protrusion of a small portion of the intestine, occurs in one out of every 5,000 live births. A "large" omphalocele, like what ShaNiya has, occurs in one out of every 10,000 live births, according to medical references.

Less than one week after she was born, the girl underwent surgery to create a thick layer of skin to cover the protrusion. Doctors used excess folds of skin from around the abdomen.

They created an organ-containing sac that looks a little like a Nerf football that was squished, covered with a sheet of skin and then sutured down to the front of her belly.

It has been painless for her, and her organs are working despite their unusual positions. She talks and laughs and plays and runs, and sometimes even falls on her stomach, her mother said.

It's a dangerous way to live, said Dr. Greg Mackay, who performed the one-hour surgery Tuesday.

"She's got no protection. She is at high risk for injuries," he said.

After the surgery Tuesday, ShaNiya was doing well, he said.