It is the first time such an operation has been undertaken, marking a milestone in tissue engineering. Similar techniques may in future offer hope for at-risk patients undergoing bypass surgery.
The girl had a blocked hepatic portal vein, which drains blood from the gut and spleen to the liver.
Without treatment, the condition can lead to serious complications including internal bleeding, spleen enlargement and even death.
Traditionally bypass surgery has been used to restore portal blood flow, using sections of vein taken from other parts of the body. This can cause other problems and is not always successful.
The new technique involved growing a new section of portal vein from the girl’s own bone marrow stem cells.
The girl has remained well since and even managed to take part in gymnastics, the Swedish team reported in the latest online edition of The Lancet medical journal.