ASHLEIGH Louw's family has commended the little girl's fighting spirit after she came through a three-hour operation with flying colours.

Ashleigh, born with her heart outside her body and chest wall more than a week ago, was yesterday successfully operated on to close the abdominal wall and put the heart back in her chest.

"The operation was a success and Ashleigh is in a critical but stable condition," Chris Hani-Baragwanath Hospital acting chief executive Sanjee Lingham said.

"We are closely monitoring her for the first 24 hours after surgery to see if she is recovering. She is being kept in the intensive care unit."

He said the operation was the first phase of corrective surgery that Ashleigh will undergo.

"Cardiologists will assess her health after the operation. After two to three months she might undergo another operation, but that will depend on her health," Lingham said.

Felicity Ferguson, Ashleigh's grandmother, said she was proud of her granddaughter for being a fighter.

"We are praying to God to make her recover quickly and to give her parents strength. The doctors have told us the operation was a success but we will only know today if she is recovering and what the way forward is," Ferguson said.

Jerome Loveland, head of paediatric surgery at the hospital, said though the heart was now inside her chest, it's still not in a normal position. Putting it right now could trigger a cardiac arrest. It will be done at a later stage.

"The defect is closed. To the naked eye the chest and abdominal wall look normal," Loveland said.

"If all goes well she could be up and about in a week."