Two conjoined twins, Abbigail and Isabelle Carlsen, who were joined at the diaphragm and pancreas and whose livers were weaved together, have been successfully separated after seven hours of surgery. Their hearts had to be re-positioned and part of their intestines, which they shared, had to be separated. For the first time in their short lives, the girls are now sleeping in separate beds.

For the first five months of their lives the two girls were fused together, face-to-face.

Lead surgeon, Dr. Christopher Moir, said the girls are critically ill and are expected to stay that way for the next 24-48 hours. Even though they are critical, which is normal at this stage after such an operation, he also described their condition as 'stable'. Most commonly at this stage, doctors will be keeping a close eye on the girls' bleeding, heart problems and blockage of tubes.

The operation was carried out at the Mayo Clinic, USA, by a team of 30 surgeons and health professionals. Doctors give the girls a 90% - 95% chance of survival.

Jesse Carlsen, the father, from Fargo, North Dakota, says his prayers have now been answered.

The operation involved:

-- Separating their intertwined livers
-- Separating their diaphragms
-- Separating their joined pancreases
-- Separating part of their intestines
-- Re-positioning their hearts
-- Taking out their gall bladders
-- Building a biliary structure as a bile duct for Abbigail

The whole operation was like a series of different operations.

The most difficult part was separating the livers, which were fused together. The circulatory structures had to be separated properly. Doctors were also concerned the girls might not have enough intestines to live normally. However, enough was separated for each girl's survival needs.