This is when surgical complications may set in, such as the formation of blood clots in the newly constructed blood vessels, internal bleeding and infection.
Dr Benjamin Carson, director of paediatric neurosurgery at the Johns Hopkins Children's Center in the United States, made the assessment at a press conference held in Baltimore on Friday to announce his participation in the surgery to separate the twins in Singapore next month, according to a report of a Singapore newspaper, The Straits Times.
The 29-year-old sisters from Shiraz who are joined at the head, came to Singapore last November after reading about the success of the Singapore medical team which separated the 10-month-old Nepalese twins, Ganga and Jamuna.
The Nepalese twins, who were also joined at the head, were separated in April 2001.
The separation of adult siblings joined at the head has never been done before, and the risks are life-threatening.
In such operations on children, four in five die or are left disabled.
Dr Carson said the age of the Iranian twins presents additional risks because adult brains are not as malleable as those of children.
This means it may be more difficult to reshape the brains after the operation so they can retain control of certain functions.
The psychological impact of separation on Ladan and Laleh is also likely to be greater than on children.
Dr Carson said: "In this case of separating adult conjoined twins, there are psychological issues that have a significant effect on both, even after a successful separation. These twins have had a life-long psychological dependence on one another."
The newspaper said doctors in Singapore decided to proceed with the operation last week after seven months of extensive testing and consultation with world experts.
Dr Carson said: "Their anatomy permits separation by an experienced team.
"The facts, together with their strong feelings, tell me it's appropriate to move forward with the surgery.
"We will remain flexible as we approach the surgery, recognizing there will be twists and turns along the way, and relying on our experience to guide our surgical plan."
Leading the surgical team are Professor Walter Tan, consulting plastic surgeon and medical director of the Raffles Hospital in Singapore, where the operation will be done, and Dr Keith Goh, a consultant neurosurgeon who was a key member of the team that operated on the Nepalese twins.
Dr Carson has been involved in three operations of twins joined at the head, including the first successful separation of such twins-- seven-month-old boys in Germany in 1987.
The other two operations were on seven-month-old girls in South Africa in 1994 and 11-month-old boys in Zambia in 1997.
... Payvand News - 6/14/03 ... --