Conjoined Twins Ethical Dilemma: When Parents Need to Sacrifice One Life For the Other

Surgical model, based on CT scan images and produced by 3D printing, showing the skeletal structures and arterial connections of conjoined twins separated at MassGeneral Hospital for Children. The New England Journal of Medicine ©2017

The public and the media have long had an insatiable hunger for heartwarming medical success stories that involve separating conjoined twins to correct one of Mother Nature's most devastating mistakes. In these tales, modern medicine swoops in to correct things, sending both children off to lead happy, independent lives.

But not every case has a completely positive prognosis. Sometimes parents and physicians must make heart-wrenching decisions, such as planning a surgery that will only save one of the lives. It's a bioethical challenge a team of doctors at MassGeneral Hospital for Children faced when a family from East Africa arrived with their conjoined twin girls, who were just 22 months old.

The sisters, fused at the pelvis and abdomen, had only three legs, one of which had a deformed foot. Internally, the girls shared several vital organ systems. They had just a single liver. Though each had her own kidney, they shared a single bladder. The twins also had one set of lower intestines, one anus and one vagina. Each child had her own spinal cord, brain and heart.

"Twin B was larger, alert, vigorous, and interactive, whereas Twin A was less active and more difficult to engage," the medical team wrote in the case study they published in the New England Journal of Medicine on Wednesday.

The smaller child (Twin A) was diagnosed by the team with a congenital cardiac condition that included an abnormally structured, oversized heart; the blood vessels that connected her lungs and heart were underdeveloped. The doctors determined Twin A was living off Twin B's blood supply through an artery connecting the two. Twin A was dying, but if things were left as they were neither would survive.

"The only reason she was still alive was she was attached to her twin, and her twin was providing good oxygen and circulation so that she was continuing to grow," said Dr. Brian Cummings, the pediatric critical care specialist who chairs the hospital's ethics committee. "As she was getting bigger her lungs and heart were deteriorating. She wasn't going to survive much longer."

The family, in Boston through sponsorship with a non-profit from their home country, had sought the help of doctors in the U.S. since they'd been told by physicians at home that the twins could not be separated. Stigma in their home country also prevented doctors from wanting to take them on as patients. Their visit to MassGeneral was their last hope.

But the surgery was still an incredibly high-risk even for Twin B, the healthy child. Cummings said a review of existing literature suggested the healthy child had roughly a 50 percent chance of surviving the complex procedure.

Cardiac anatomy of the twins showing the arterial connection. The New England Journal of Medicine ©2017

"We spent a lot of time talking about this, and would we be willing to do it and we went through all that emotional work," said Cummings. "Some people think separating them when you know one will die is an act of killing, and other people think it's the only humane thing."

That deliberation also required the team to arrive at an ethical decision of whether the girls should be treated as one or two patients. In many ways, Twin A was what's known as a parasitic conjoined twin, since she was surviving off the life of her sister. Parasitic twins are typically undeveloped, often they aren't even the entire person. Sometimes a parasitic twin is just a single body part like a leg or an arm.

"When you get down to it they had two heads, two brains and two spinal cords. Really they had two personalities," said Cummings. "It was really clear to everyone here that they should be considered two people."

Arthur Caplan, a professor of bioethics at New York University's Langone Medical Center and founding director of NYULMC's division of medical ethics, said that in this case the choice, while unsettling, seemed relatively straightforward. While the final decision is always up the parents, he believes that in this instance separating them was the right decision. But these cases are often complicated. "If you're really not at risk of losing both I do think there ought to be a lot of counseling and meeting with doctors," he said. "It may seem freakish and terrible to not separate them. And while it's highly unusual, it's still possible they can achieve a pretty good quality of life."

In the end the parents opted for the separation surgery, a procedure that took 14 hours. Cummings said the surviving twin is doing well; she's hitting all of her milestones but the irregular anatomy of her pelvis will require ongoing physical therapy to learn to walk. She'll eventually need additional surgeries.

Though the parents were not willing to be interviewed by the media, they told the doctors the most difficult part of the process was the uncertainty of the surgical separation. And knowing with certainty what would happen regardless—that Twin A would die—was overwhelming for the family as well as the hospital staff.

Cummings said the parents and the hospital staff received support from clergy. "The family had their chance to say goodbye, and even before beginning of the surgery the whole staffing community had a moment together."