Halfway through marathon surgery to separate conjoined twins Ladan and Laleh Bijani, neurosurgeon Benjamin S. Carson tried to persuade the twins' designated next-of-kin to halt the operation for a week or longer to assess a surprise development and re-plan the rest of the daunting procedure.
"I said the chances of one of them dying were almost 100 percent if we were to proceed," Carson recalled yesterday, a day after his return from Singapore, where the 53-hour operation ended with the twins' death Tuesday. "And if the other one were to survive, would the other one ever forgive us for not pausing and taking the time to maybe give them both a chance?"
But the person chosen by the twins to represent their interests - whom the medical team agreed not to identify - rejected the idea of pausing and completing the surgery in stages over a period of weeks, a technique sometimes used in complex brain operations.
The representative "said if they woke up still joined, the level of depression would be so bad that they just couldn't imagine it," Carson said.
So the lead surgeons - Carson, director of pediatric neurosurgery at Johns Hopkins Children's Center, and Dr. Keith Goh, of Singapore's Raffles Hospital - returned to the operating room. The team of 12 surgeons and 100 nurses and other medical personnel forged ahead with the separation the 29-year-old twins had desperately desired.
As he resumed cutting without knowing exactly where Ladan's blood had rerouted from a clogged graft, Carson said it felt like "going into a dark jungle where there's a hungry tiger, with no gun."
To complete the separation, the surgeons had to cut through 2-inch-thick bone at the base of the skulls, which Carson said was "like a brick." Then they cut into the dura mater, the tough membrane covering the brain, which was 10 times thicker than normal.
It was only then that they discovered that Ladan's blood was returning to the heart through vessels in the dura mater. He described the next minutes of surgery - the final separation - as an agonizing, losing battle to control uncontrollable bleeding.
"Even when you put clips on to try to stop the bleeding, the clips would just rupture the membrane - it was under that much tension," Carson said. "You'd put a clip on to try to stop the bleeding, and it would just rupture in front of the clip. You'd put another clip on and it would rupture in front of that one. ... So basically, it was over at that point. There wasn't anything more we could do."
Nonetheless, the doctors completed the separation, fulfilling the twins' dream. But Ladan died within an hour, and Laleh died 90 minutes later.
Carson, 51, spoke yesterday at a news briefing at Johns Hopkins Hospital, which drew international coverage, and in a separate interview with The Sun.
He has performed "many thousands" of brain operations in his career, including three surgeries to separate babies joined at the head.
But the Singapore case - the first attempt to separate adults joined at the head - was the longest single operation he had participated in and the one with the highest risk of death, which he had estimated beforehand at 50 percent.
During the operation, the surgical team took breaks of an hour or two at a time to sleep, Carson said. At one point he worked without a break for 14 hours, he said.
He looked rested yesterday and spoke calmly of the drama at Raffles Hospital, where the twins died on separate beds. He described himself as "disappointed but not depressed" by the outcome, which he said had taught the surgeons valuable lessons.
The sisters' bodies were flown to Tehran yesterday morning and driven away in two Red Cross ambulances, the Associated Press reported. Hundreds of weeping Iranians waited to greet the caskets when they reached the twins' village of Lohsrab, 680 miles southwest of the capital.
Carson's previous surgeries to separate twins joined at the head - a rarity that occurs once in about 2 million births - were on infants less than a year old.
The surgery to separate the Bijani sisters proved more challenging than doctors expected.
They found that the two brains, while separate, had grown far more connections than was the case with the babies. Surgeons had to perform painstaking microsurgery to disengage them.
But the biggest surprise came when a leg vein they had grafted onto Ladan's brain to replace the saggital sinus, the major vessel shared by the twins, repeatedly became clogged with blood clots.
Ordinarily, if the saggital sinus is blocked, the brain swells dangerously within minutes, Carson said. Remarkably, Ladan's brain remained "perfectly normal," proving to the surgeons that the blood must be returning to the heart through unknown vessels.
"The very fact that one of the twins could have the entire output of the saggital sinus clotted off and her brain still be OK meant that that blood was going somewhere that we didn't know about," Carson said.
This uncertainty led Carson to request the permission of the designated next-of-kin to take time to study where the blood was going. "You know that you've substantially changed the circulation," he said. "And it just obviously improves your chances enormously if you know what you're doing."
He, fellow surgeon Goh and the chief executive officer of Raffles Hospital spoke with the twins' chosen representative, who was accompanied by others close to the women.
"I thought when we went out there we would be able to convince them," he said. While "we didn't take a vote," Carson said he thought the other doctors were willing to pause the surgery if the representative had approved.
In a post-operative meeting of a dozen team members the day after the twins died, he said, "I don't think anyone disagreed" with the idea that it might have been better to proceed with the operation in stages.
Carson acknowledged that had the surgeons paused for a week or two, infection, stroke or other complications might have killed the sisters. But he said both brains were in good shape when a possible halt was discussed.
The pre-operative understanding with the twins was that the surgeons would proceed to separation no matter the risk, he said. Had he been involved in the original discussions, Carson said, he would have pressed for a more flexible agreement to permit possible staging of the surgery.
"If it had been done at Hopkins and I had been involved from the beginning, I don't think I personally would have accepted that ultimatum" - to proceed to separation no matter what, Carson said. "In this situation, the twins' desire to go for broke took precedence."
But Carson did not second-guess the twins' fervent desire to live separate lives. He spoke with them for an hour on the day he arrived in Singapore, finding them "just delightful" and persuading himself they preferred death to continuing their attached existence.
"It's pretty easy for people who are not conjoined to say, 'Hey, it's not so bad to be joined.' But when you're an intelligent individual and have strong desires in terms of where you want your life to go ... and they vary significantly from the person you're stuck to, your quality of life declines enormously," he said.
He noted that it is not unusual for difficult operations to fail on the first attempts, citing the case of Hopkins neurosurgeon Walter Dandy (1886-1946) and his pioneering attempts to operate on the lower brain structure called the posterior fossa.
"People said, 'You can't operate on the posterior fossa,'" Carson said. "So he operated, and the patient died. He operated and the next one died. And they kept dying - the first 13.
"And now," he said, "we do that operation routinely."