Born with half a skull, N.J. baby was expected to die. It is now 7 months since his extraordinary surgery.

The doctors and nurses spoke the blunt words more times than Maria and Augusto Santa Maria can remember:

Your baby is going to die.

They told the New Jersey couple it might happen during pregnancy, or it might happen a few hours after birth. Within a day, tops.

The baby was born at 35 weeks with no skull above his eyebrows and ears, roughly the area where a baseball cap would rest. Much of his brain had not formed properly.

Yet seven months later, after a highly unusual surgery at Hackensack University Medical Center, baby Lucas is still alive. He eats and sleeps like a champ, and he holds his head up during tummy time.

He is lethargic when awake, and almost certain to have developmental issues. There is no telling whether he will learn to walk and talk.

But all the family wanted was the chance to hold Lucas at home in their apartment, in Garfield, N.J., even for a day — and now that seems practically routine. The Santa Marias are thinking ahead to next year, when doctors may fashion a bone graft to replace the missing portion of the boy’s skull.

“We really don’t know what to expect," said Tim Vogel, the surgeon who operated on Lucas three days after he was born in March. “We’re in uncharted territory with him.”

Ten weeks into the pregnancy, when Maria Santa Maria got her first ultrasound, the technician at the clinic asked if it was her first. No, she said, smiling as she thought of her three energetic girls, Sophia, Mia, and Giana, whom she had delivered with no complications.

“OK, so we don’t have anything to worry about,” the tech said.

The scan showed otherwise.

Though the fetus was little bigger than a strawberry, it was clear that the head had not formed properly.

His condition was called exencephaly, meaning the brain was located partly outside the skull. As the pregnancy progressed, the developing brain likely would deteriorate from being exposed to amniotic fluid and from tugging forces as the fetus moved inside the mother’s womb.

It is part of a broader group of conditions called neural-tube defects, defined as a failure of the spinal column to close somewhere along its length. If the opening is near the bottom, the child will have spina bifida, most often meaning partial paralysis. If the opening is near the top, the result is usually anencephaly, in which most of the brain is missing. Collectively, these conditions occur in 5 out of 10,000 live births.

Exencephaly is among the rarest, said Daniel R. Dirnberger, medical director of neonatology at Nemours/Alfred I. duPont Hospital for Children. It is thought to occur in cases that ordinarily would progress to anencephaly, but the brain somehow remains protected in the womb despite an incomplete skull.

A search of the medical literature reveals just a few reports of such children born alive, said Dirnberger, who was not involved in Lucas’ care. In those cases, the children survived for just a few hours.

The Santa Marias were devastated by the news. At one point when driving home from an errand during the pregnancy, Augusto Santa Maria was so preoccupied with worry that he drove past the family’s apartment.

On several occasions, when the couple went back for checkups, they were given the option of an abortion. That would go against their faith, they said. They decided they wanted to hold Lucas.

“Even if it was just a minute or two,” Augusto Santa Maria said.

Vogel, who sees patients at North Jersey Brain & Spine Center in addition to performing surgery at Hackensack, first heard about the Santa Marias midway through the pregnancy.

Neonatologist Anne-Lise Jacobsen told him she was counseling the family about palliative care.

But scans of the developing fetus seemed to indicate the brain was partly intact, and Vogel wondered if he could help.

Lucas was born at 35 weeks, close to term, in a vaginal delivery. A cesarean section would have increased the risk for the mother, Jacobsen said. Because Lucas was expected to die no matter what, Maria Santa Maria agreed.

Augusto Santa Maria saw the baby’s face first. Then came a large, intact sac of whitish, near-translucent skin where the top of his skull should have been. Most of it was fluid.

“It was like a water balloon,” the father said.

The family moved to the hospital’s comfort care wing.

But Lucas did not die, and he even drank from a bottle. The next day hospital staff asked if the family was ready to take him home.

Maria Santa Maria was alarmed, worried that his condition was too fragile.

“It was hard to handle him,” she said.

After consulting with Jacobsen, Vogel offered the family what he described as a palliative surgery, to stabilize the boy’s condition so they could take him home to die.

Vogel would drain the fluid from the sac, remove any malformed brain and skin, and try to cover the open portion of the baby’s skull as best he could. It appeared that the dura, a rugged layer of tissue that normally covers the brain, was splayed to the side like layers of an onion, and Vogel thought there was enough to fashion a protective layer.

The entire top half of Lucas’ head would feel like the fontanel, the small soft spot on a normal baby’s head where the skull bones have yet to fuse. Yet it would be safe enough for the family to carry him without worry.

“We just kept trusting,” Maria Santa Maria said. “If he’s here already, why not give it a shot?”

Vogel performed the six-hour surgery on March 11, three days after Lucas was born.

Some of the staff at Hackensack’s neonatal intensive care unit argued surgery would cause unnecessary suffering, he said.

Jacobsen, the neonatologist, thought the procedure was OK so long as the family understood that Lucas likely would not survive it.

“A lot of surgeons aren’t going to take that risk,” she said. “No surgeon wants a patient to die on the table. And they want whatever they do to have some sort of benefit that outweighs the risk of the procedure.”

As Vogel began his work, what he found was somewhat encouraging. The brain stem, which controls reflexive actions, was intact, explaining why the baby could eat and breathe on his own.

But half of the cerebral cortex, the outer layer that governs higher-order thinking, was badly damaged and had to be removed — with great care, so as not to provoke a seizure.

The rest of the cortex was slightly underdeveloped, so Vogel kept it. He also managed to preserve the four major arteries that traverse the brain, as well as their key branches. And there was enough of the rugged dura to bridge the gap in the boy’s skull.

The boy woke after surgery, and surprised everyone by breathing on his own.

After just a week, he was healed enough to go home. Seven months later, he is at the center of family life, doted on by his three big sisters. They wrote a song to the tune of “Baa, Baa Black Sheep,” which starts “Lucas, Lucas, open your eyes. You’re so adorable, you make us shine.”

Bone has started to grow a bit higher on the side of his head, and he may be a candidate for a bone graft next year to help the process along. A physical therapist is scheduled to visit this fall.

Physicians who have heard about the case are surprised the boy has done so well, though they caution that his future is uncertain.

One is Alan R. Cohen, director of pediatric neurosurgery at Johns Hopkins University, who is a mentor of Vogel’s.

“It was a clever neurosurgical innovation that they were able to do this, to allow this child to be able to come home with his family,” Cohen said. “He is doing better than one would expect.”

The Santa Marias have health insurance, and are not looking for any help. They shared their story to illustrate that grave medical decisions should be made with care, Augusto Santa Maria said.

“Don’t take the first option,” he said.

The way Maria Santa Maria sees it, Lucas was unwilling to give up. So why should they?

“He always did more than they were expecting him to do,” she said. “We just keep hoping for the best."