Doctors in southwest China's Chongqing Municipality have completed surgery on a 112-day old boy with an extremely rare condition: Part of his heart was outside his chest.

Known as Pentalogy of Cantrell, the abnormality affects about one in a million babies. The boy, An'an, is from Xianyang City of Shaanxi Province. He was transferred to the Children's Hospital of Chongqing Medical University, for surgery on June 21.

Cardiologist Wu Chun created space for the heart in the boy's chest with a titanium plate.

"He has survived the most critical stage, and remains stable," Wu said on Friday.p This is the third time Wu has performed this surgery in the last ten years. "Both the other patients are in good health," he said.

"The Cantrell defect can be life-threatening if not treated. The earlier the surgery, the better," he said.