Conjoined twins in surgery at Melbourne's Royal Children's Hospital

Surgery continues on conjoined twins

Yet to separate the twins' brains

Beyond expected completion time

DELICATE surgery to separate conjoined twins Trishna and Krishna has continued beyond the operation's expected completion time.

Julie Webber, spokesman for the Royal Children's Hospital in Melbourne, said surgeons were still working to separate the twins' brains, the Herald Sun reports.

She said the operation was still on track and doctors had encountered no major complications so far.

Dr Ian McKenzie, director of anaesthesiology at the Royal Children's Hospital, said earlier that the entire operation was expected to last until 3am (AEDT).

"It's just going absolutely according to plan at the moment and we couldn't be happier," Dr McKenzie said.

He said that surgeons are near the end of the process of separating the twins' brains, and will then have to separate the final piece of bone.

"That's a point of excitement, where we'll consider them separated," he said.

Dr McKenzie said that even if the separation goes well the success of the surgery would not be known for some time.

"Every time we have an operation we worry it could be infected in the next few days or week.

"Part of the reconstruction is some artificial tissue goes in there, so that's always something you worry that might get infected. And that can be quite a nasty complication, so things can happen.

"I don't think anybody will be dropping their guard for a long time, but there will be points of progress, like getting out of intensive care in a few days, we're hoping.''

RCH head of surgery Leo Donnan said the marathon operation was progressing well, but all involved remained cautious.

"Their bodies will be changing dramatically, both physically and emotionally," he said.

Plastic and maxillofacial surgeon Professor Tony Holmes said "the unknown ... is what actually happens when you separate finally the cerebral circulations, because that is a change in hemodynamics (blood movement) so the pressures will be different in each twin.''

"It's over those few early minutes when the pressures equilibrate in the brain, that they're the things that we're worried about.

"But the children are prepared as well as could possibly be and we're cautiously optimistic that everything is going particularly well.''

Prof Holmes said Moira Kelly, who rescued the Bangladeshi orphans, was understandably distressed as she left the girls in the hands of surgeons.

"When the children went into the operating theatre ... Moira was there giving them, you know, a farewell kiss and good luck,'' he said.

"She was relatively distressed as one would be if it was your child. The kids were fine, OK, they looked as healthy and happy as anything but they were sedated.''

As the twins were wheeled from the Intensive Care Unit to the operating theatre, Ms Kelly was there to kiss them, although they were already asleep.

After being wheeled into the operating theatre at 8.30am, it took 90 minutes just to arrange the girls on the operating table and the equipment around them.

After several hours of positioning tubes to ensure there was no pressure on the eyes, surgeons made their first cut about 10am.

Once the actual surgery started, about 10am, Prof Holmes cut the skin away from the skull bone to allow neurosurgeons access to blood vessels and their brains.