A team of surgeons in Singapore yesterday completed a marathon 103-hour operation to separate conjoined twin sisters born sharing a brain cavity.
Doctors said they were "cautiously optimistic" that Ganga and Jamuna Shrestha, from Nepal, would recover but admitted it was too early to say how much brain damage they might have suffered.
The girls were last night recovering - in separate rooms for the first time in their 11month lives - after more than four days on the surgeons' table.
Dr Keith Goh, the neurosurgeon who was instrumental in bringing the twins to Singapore, said: "Happily we had no adverse events during the entire five days, so we are cautiously optimistic." He admitted there was bound to have been brain damage, but said it was too early to gauge the extent of it, or how much the girls' ability to function would be impaired.
Before the operation doctors said they had very distinct personalities. Ganga was much feistier and always hungry, while Jamuna was more shy.
The girls' parents and grandfather, who had broken their vigil at the hospital only to pray at a local Hindu temple, declined to speak publicly yesterday.
Dr Muiris Houston, Medical Correspondent, adds:
The doctors had originally planned a 36-hour operation - until they discovered the blood vessels around the brains were enmeshed and required painstaking unravelling. The twins were born with their brains twisted into a helix and the left sides pulled into a horn shape. They shared a single skull.
Plastic surgeons spent one day placing man-made material around the girls' heads to act as a skull. Polymer sheets were also introduced to act as a base for new cell growth. Skin grafts from the girls thighs and backs were then used to cover their heads.
Conjoined or Siamese twins joined at the head are very rare. They occur in one in two million live births. Successful surgery in these cases is even rarer.
The term Siamese comes from male twins, Chang and Eng, born in Siam in 1811. The condition arises when the ovum of identical twins fails to separate after its first division and they remain partially jointed. The twins were still sedated yesterday to allow their vital signs to stabilise. After they regain consciousness, doctors will be able to test their brain function. Electrodes were used during the surgery to stimulate the nervous system in an attempt to preserve speech and logic centres.