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Slowly, one blood vessel at a time, conjoined twins Krishna and Trishna are being separated.
Their hospital team is deliberately spending more than a year on the project, to reduce the risks for the young girls from Bangladesh.
Rapid separations of twins with their complex and extremely rare form of connection almost always leads to a poor outcome, says their New Zealand-trained plastic surgeon Andrew Greensmith, 39.
Only one or two of the "handful" of successful separations since the 1950s of this type of join had resulted in normal brain function and general independence.
Krishna and Trishna, who will turn 2 this month, are unable to walk or even sit up and cannot look at each other. They are joined at the back of the skull and are known medically as "craniopagus" twins.
The incidence of all conjoined twins is estimated to be one in roughly 100,000 births. Craniopagus twinning is far more rare, at around one in 2.5 million births.
Australia's Children First Foundation took Krishna and Trishna to Melbourne for assessment at Royal Children's Hospital and last January began the operations leading to their high-risk separation, expected to be done next February or March.
The foundation - whose executive director Moira Kelly is the twins' guardian - says their parents put them into an orphanage. The parents were in a "helpless situation" and unable to care for the girls. The foundation has pledges to cover the expected A$250,000 ($300,708) for their hospital treatment.
Mr Greensmith, whose training began in New Zealand and whose parents live in Auckland, said the girls' skulls were fused together.
