An expert neurosurgeon from the US-based Johns Hopkins Children's Centre expressed Tuesday his optimism over the feasibility of operating upon the 10-year old conjoined Indian twins.

"Having analysed their medical reports, we can say with certain degree of confidence that the operation is possible. But for that, we need to do a battery of other tests and gather more details before taking the final step," said Benjamin Carson who has flown down specifically as consultant to the doctors at the Indraprastha Apollo Hospital.

Parents of Saba and Farah Shakeel, ten-year old sisters conjoined at head, had brought them from Patna in the eastern Indian state of Bihar to the capital to seek medical opinion on a possible surgery to separate them.

"From my past experience, I must say that there is no need to hurry. Patience and planning are the two keywords, which should govern our mind before the deciding a final date for operation.

"It is certainly going to take a few months to narrow down on a date and for that I may have to come to India more than once," Carson told.

However, doctors at the Apollo Hospital said the separation of the duo would take place through six different stages.

The separation would require multiple steps. The first step would be the three-dimensional modeling of the brain, which will be done by Carson and his team in the US. The virtual brain will help the doctors to understand the anatomy closely and conduct mock operation.

Three months later a test will be carried out to know the feasibility of recreating the blood vessels as the girls share a major blood drainage vessel in the brain. This would be followed by distraction of the blood vessels.

The next stage will involve plastic surgeons to create skin tissues to take care of any skin deficiency after the surgery.

It will then take three months to decide on the date of surgery for separation. And after that the kidney transplant would also take place as one of the twins has both the kidneys while the other has none.

"Farah's kidneys are performing the work of four kidneys and taking into account the sensitivity of the situation, we are planning to have this transplantation after the main operation," said Anupam Sibal, medical director of the hospital.

"It will take nine months to reach the final date and at least 60 doctors have to work in close cooperation over a period of four days," he added.

Carson said the six-stage preparation is a new approach to this kind of operation and expects a fair degree of success.

"This approach is unique and has never been applied before anywhere in the world. From my past experience, I have learnt a lot and want to take a safe stand before entering the operation theatre," he explained.

Meanwhile, doctors at Apollo explained the process to the parents of the twins and were ready to start working on the plan after getting permission from the family.

Sheikh Mohammed bin Zayed Al Nahyan, the crown prince of Abu Dhabi, who decided to help the twins after seeing their picture in an Indian newspaper, will bear all the expenses of the operation - estimated to be more than $1 million.