Outpouring of grief as twins die
Women underwent 50 hours of continuous surgery
(CNN) -- The deaths of two conjoined Iranian twins following unprecedented surgery to separate them has prompted an outpouring of grief around the world.
Ladan Bijani died when her blood circulation failed after the operation to separate the twins' brains, officials at Singapore's Raffles Hospital say. Her sister Laleh died when her circulation failed one-and-a-half hours later.
Mourners gathered outside of Raffles Hospital and the sad news spread quickly through the twins' home country of Iran. Thousands of tributes have been sent to CNN.com. (Your say)
The 29-year-old twins -- both law graduates -- had two distinct brains, but they were fused together, requiring a team of international doctors to spend many painstaking hours separating them in surgery dubbed "Operation Hope."
At a news conference, hospital chairman Dr. Loo Choon Yong said that when complications arose after their brains were separated, surgeons had the option to attempt to stabilize them and transfer them to intensive care, or continue with the most risky part of the surgery.
"The team wanted to know once again what were the wishes of Ladan and Laleh," he said. "We were told that Ladan and Laleh's wishes were to be separated under all circumstances.
"We knew the risks were great -- we knew one of the scenarios was that we would lose both of them," he said.
He said the twins took 50 hours of anesthesia and continuous surgery well and doctors had been "hopeful but very cautious."
After the brain separation, there was some bleeding which they tolerated well for a while, he said. But Ladan's surgery began to fail and she died at 2.30 p.m. (0630 GMT) on Tuesday.
"Laleh was critical but holding on. Surgery to her brain continued. She continued to receive a blood transfusion. However, her circulation began to fail also. The whole team did everything to save her." Laleh died at one-and-a-half hours later.
"We are very grateful and thankful for the help and sacrifice of so many specialists, doctors, teachers, nurses and other people, all united with one common purpose, to do something -- anything -- that can help Ladan and Laleh fulfill their wishes.
"We also want to thank so many people for their prayers -- whether they are Christian, Buddhist, Hindu, or Muslim -- everyone had been praying for the twins and we are grateful because as doctors we know there's only so much we can do, and the rest we have to leave it to the Almighty."
In Iran, the operation has dominated news coverage in the country. "May God bless their souls and reward them with peace in their eternal life," said the Islamic Republic of Iran News Agency, in condolences "to all Iranians across the globe on loss of the two kind sisters on Tuesday in Singapore City."
Willing to face the risks
The twins made a big impression around the world with their display of courage and bravery going into the dangerous operation.
Doctors at one point tried to talk them out of the operation, but the sisters said they were willing to accept the risks and face those dangers to lead separate lives.
Earlier Tuesday, neurosurgeons carefully teased apart packed brain tissue millimeter by millimeter in a delicate and risky procedure on the third day of the operation.
Surgery to separate the twins, who were joined only at the head, began on Sunday and doctors had to battle against unstable blood pressure levels as they slowly split apart the fused brains.
The complicated process of paring apart the twins' brains began late Monday and separating them was one of the most challenging parts of the surgery.
Prior to separating the brains, surgeons completed the process of rerouting a single large vein that served to drain both their brains.
An international team of neurosurgeons, dozens of doctors, plus support staff created a bypass for Ladan, using a vein grafted from her leg.
This caused another complication, Kumar said, as blood circulation between the twins became unstable.
A landmark procedure
The operation was a landmark procedure. Although Singapore doctors performed a similar operation in 2001 on infant Nepalese girls, surgery on adult twins is unprecedented.
The operation is more difficult in adults than in children whose brains are better able to recover from the surgery.
Twins joined at the head are the rarest of conjoined twins, occurring one in every 2 million births. Twins joined elsewhere occur once in every 100,000 births.
The Bijanis' operation was considered elective because the women likely would live a normal life span without it.
However, testing showed the sisters had high intracranial pressure, which, if untreated, could cause frequent debilitating migraines and impaired vision as well as deteriorating brain function, the hospital said.
The sisters made an impression on Singapore's public, in part because of their cheerful demeanor before the operation. Thousands of cards, flowers, and offers of support were sent to the hospital from around the world.
The hospital paid for pre-operative fees and the medical costs involved in operation. The operating surgeons waived their professional fees. The government of Iran said Monday it would pay $300,000 for post-operative care.
-- CNN Medical Correspondent Dr. Sanjay Gupta and Journalist Michael Dwyer contributed to this report.