It is known that the 15-month-old women come together with their shared liver, but doctors say they would not be able to tell if they also shared a gut up to when the sisters do not go under the knife for the first time.
Dr. Crameri said that one of the risks was the use of anesthetic, since they did not know how a twin would react to the other who received it.
On Thursday afternoon, the twins traveled to Melbourne from Kilmore, where they stayed in the Children First Foundation's retreat.  Gemini Nima and Dawa in a previous visit to the hospital. "src =" https://static.ffx.io/images/$zoom_0.403%2C$multiply_1%2C$ratio_1.776846%2C$width_1059%2C$x_0%2C$y_0/t_crop_custom/w_768/t_sharpen%2Cq_auto % 2Cf_auto / 2c54e2db099afa28858b4313aa3a6cc033c31c51 "/>
Gemini Nima and Dawa in a previous visit to the hospital.
Elizabeth Lodge, managing director of charity, said that the mother of the children Bhumchu Zangmo felt "a little scared" for the operation, but he was still in a good mood.
Friday, praying and meditating.
"He just wants that tranquility and finds it quiet," Mrs. Lodge said.
"She still has this extraordinary calm on her, which is simply incredible. "
Dr. Crameri said there were unexpected problems during the work the hospital had all the resources and experts available that it would need.
One of the largest operating theaters was requirement for the procedure, which will involve two teams of anesthesiologists – one for each sister.
The surgical team will also split in half once the initial separation is complete.
About 18 people will be in the operating room – including Dr. Karma Sherub, Bhutanase pediatric surgeon, who flew to Melbourne this week.
Dr. Sherub first met the girls when they only had one day and played an important role in bringing the twins to Australia, having already spent time in the country as a medical scholarship winner.
Nima and Dawa were born by a caesarean section on July 13 in a hospital region in the Himalayan kingdom of Bhutan, shocking doctors and the family of twins who expected twins, but not they knew they were conjoined.
It is expected that girls will spend about a month in hospital after surgery and dr. Sherub formerly said The Age may take some time to recover some of their milestones
"Above all Dawa, since she has not moved much, some of the muscles of her limbs are not developed, because they are not been used.
"Nima is trying to get up and walk. He's struggling because Dawa is holding her back. "
The carers claim that the twins have improved tremendously since they arrived in Melbourne last month, putting together two kilograms and growing in confidence.
As the public eagerly awaits good news the Royal Children & # 39 ; s Hospital should not release any information on the progress of the operation until 4pm on Friday, with Dr. Crameri to give her first update on the girls early Saturday morning
Aisha Dow reports health for The Age and is a former citizen reporter.
Liam is a scientific journalist for Fairfax Media