SINGAPORE, July 6: An unprecedented operation to separate adult twins joined at the head reached a critical phase early on Monday when doctors in Singapore were to try to split a major blood vessel that serves the sisters’ brains.

Dozens of doctors and scores of support staff are helping in the operation to separate Iranian twin sisters Laleh and Ladan Bijani, 29, in surgery expected to last at least two days, possibly three.

Singapore doctors performed a similar operation in 2001 on infant girls from Nepal, but experts say an operation on adult twins is unprecedented.

Surgery began on Sunday around noon and by 3 a.m. on Monday doctors had harvested a vein from Ladan’s right thigh and were to have begun the crucial blood vessel work.

The law-graduate twins who are willing to risk death to lead separate lives share a major blood vessel between their two brains. Surgeons need the leg vein to fashion a new blood vessel for one of the sisters before their skulls can be separated.

Dr Prem Kumar Nair, a spokesman for Raffles Hospital, said no decision had been made as to which sister would get the grafted vein.

“The graft was taken from Ladan but it will go into whatever section, wherever the bypass has to be constructed, and that is something that has to be decided by neurosurgeons after they have visualised the brain,” Nair said.

“It is probably one of the most critical aspects of the surgery. As we have said before, the key component in Laleh and Ladan’s surgery is the shared blood vessel,” he added.

Asked to evaluate the operation, he said the schedule was off by a couple of hours but everything was going as planned.

“We haven’t really met any problems so far, but I would anticipate that the next 12 to 24 hours will be a very critical period and that may be where we will have to traverse some possible difficulties,” he told reporters and anxious Iranian friends gathered near the hospital’s entrance.

The sisters laughed and joked with friends as they were wheeled into an operating theatre early on Sunday, ending years of convincing doctors of their wish to lead separate lives.

German doctors had turned away the Bijanis in 1996, deeming that splitting them could prove fatal.

The twins have not been deterred by the risks — Ladan wants to be a lawyer in her home town of Shiraz, while Laleh wants to be a journalist in Tehran.

“We’ve been praying every day for our operation. We are excited about it as we’ve waited 29 years for it,” they said in a statement released by the hospital this week.

“Both of us have started on this journey together and we hope that the operation will finally bring us to the end of this difficult path, and we may begin our new and wonderful lives as two separate persons.”

Iranian President Mohammad Khatami said he prayed for the twins and wished them success.

“I wish to see dear and patient Laleh and Ladan healthy and cheerful among us very soon, and I am sure that the prayers of the Iranian people will help the success of the operation,” he said in a message carried by the official IRNA news agency.

An international team of 28 doctors are supported by about 100 nursing and paramedical staff in the marathon surgery, with the operation led by neurosurgeon Dr Keith Goh.

Goh is being assisted by Dr Walter Tan, a plastic surgeon, and Dr Ben Carson, director of paediatric neurosurgery at Johns Hopkins University in Baltimore.

Carson successfully separated twin boys joined at the head in Germany in 1987 and six-month-old twin girls in 1997.

Goh was part of the team that successfully separated 11-month-old Nepali girls Jamuna and Ganga Shrestha, joined at the head, in a four-day operation in April 2001.

Spokesman Nair said that during the entire operation, the twins will be in a sitting position supported by a special frame.

The nurses and technicians will work in shifts but the neurosurgeons will be present throughout the 12-hour operation, working from the front and back of the twin’s heads.

Twins joined at the head occur only once in every two million live births, and successful separation is even rarer.—Reuters