PEORIA — Tiny West Peoria resident Harleigh Berry is going to make it into the history books.

At 3 weeks 2 days old, Harleigh had an extracranial-to-intracranial bypass to repair an artery damaged by a pair of aneurysms in her brain. Her doctors say she is the youngest documented patient in the world to have undergone the procedure.

Harleigh was a perfectly normal child until the evening of June 6, when she suffered the aneurysms.

“I was holding her and she made a really funny noise and flung her arms out,” said Ashleigh Berry, Harleigh’s mother. “Then she did it again. Her legs went limp and she stopped breathing.”

Berry laid her daughter on the floor and began chest compressions while her husband, Patrick, dialed 9-1-1. Within minutes, EMTs were at the family’s home — the fire station is two blocks away — and minutes later they were headed to the hospital.

When the parents arrived at the emergency room at OSF HealthCare Saint Francis Medical Center, they were heartened to hear Harleigh crying.

“We thought everything was OK,” said Berry. “A lady came in and explained everything that could be wrong, and she made us feel like everything was going to be OK. There were lots of things that could have caused it — the worst-case scenario was a brain aneurysm.”

Subsequent tests confirmed the worst. Harleigh actually had two aneurysms, and one had burst.

Aneurysms are rare in children, said Dr. Jeffrey Klopfenstein, the neurosurgeon who performed the surgery.

“For some reason we don’t have the answer for, Harleigh developed weakening in the sidewall of the blood vessel, and she developed the aneurysm,” he said.

The surgical team knew going in that it wasn’t going to be an easy operation.

“The study suggested it was going to be difficult to fix, and that a bypass might be required,” said Klopfenstein.

Although Klopfenstein has performed many extracranial-to-intracranial bypasses over the years, they are not common. He only does about 10 to 20 a year, and he has never done one on a child, much less an infant.

On the morning of June 8, the surgical team, which included anesthesiologist Dr. John Kula, quickly confirmed their fears. The aneurysm had wreaked havoc in Harleigh’s brain. While many aneurysms can be clipped shut, the damage was too great in Harleigh’s case, said Klopfenstein. The two aneurysms were right next to each other, on a major artery supplying blood to the right side of the brain. The damaged area was so large it affected several smaller blood vessels carrying blood deep into the brain, including one which controls motion on the left side of the body.

After determining the section of artery could not be saved, the surgical team went to work harvesting a blood vessel from Harleigh’s scalp. It would be stitched into the artery just before and after the damaged section.

“It was the smallest bypass that I have ever done, as you can imagine,” said Klopfenstein. “We normally want to see a blood vessel around 2 millimeters in size. Harleigh’s donor vessel was about .4 millimeter in size. The suture we used is barely visible to the naked eye — smaller than a human hair.”

Klopfenstein did the intricate work with the aid of a microscope.

“It required a special breed of concentration,” he said.

Meanwhile, Harleigh’s parents and about 30 friends and family members waited anxiously for six hours. Although the nurse checked in every hour throughout most of the surgery, late in the procedure the updates ceased.

“It was so scary,” said Berry. “Finally Dr. Klopfenstein came in. He said, ‘I’m not God, but I’m the tool that he gave you.’”

He went on to explain the severity of Harleigh’s brain injury.

“He told us there was a good possibility that her left side would be paralyzed,” said Berry.

It wasn’t good news, but the family took comfort in the fact that Harleigh was still alive, Berry said.

The tiny patient was moved to the Pediatric Critical Care Unit at OSF HealthCare Children’s Hospital of Illinois. Her parents stayed with her around the clock, and a nurse kept constant watch over the infant.

Harleigh was kept sedated and paralyzed to give her brain time to heal. On June 10 she woke up, and that evening she began moving her right arm and right leg, and possibly her left leg, but her left arm was still. On the morning of June 11, the parents woke up to good news.

“The nurse told us that we have movement in the left arm,” said Berry.

Later that morning, Klopfenstein visited his youngest patient.

“I had just gotten out of the shower and I heard him come in and ask the nurse about movement. I heard him say ‘All four?’ And I saw him throw his hands up in the air as if to say ‘Score,’ and he did a little happy dance,” said Berry.

Said Klopfenstein: “I was elated. I was absolutely ecstatic when I walked in and saw her start moving her arm. It was a special moment not only in her case, but in my career.”

There were more tense moments over the 26 days Harleigh spent in the hospital. One lung collapsed twice, and she had seizures, a condition she will have to be medicated for over the next several years, her mother said.

Doctors had to insert a drain when fluid buildup caused pressure on Harleigh’s brain. She also suffered from vasospasm, a condition where the blood vessels in the brain constrict.

“Dr. (Kenneth) Fraser took her back and injected medicine into the blood vessels to treat the vasospasm, and she appears to have made it through with little ramifications from that,” said Klopfenstein.

Harleigh also suffered several small strokes, but the damage appears to be minimal, according to Klopfenstein.

“Children are amazing. They can develop alternate pathways and they can compensate for brain volume loss," he said. "They are still in the process of developing neurofunctions, and because of that neuroplasticity they can overcome brain trauma much better than adults.”

Shortly after noon Monday, Harleigh was released from the hospital and her parents took her home. They reunited with Harleigh’s brother, 3-year-old Patrick Berry III, who was cared for by both his grandmothers while his sister was in the hospital.

Since Harleigh is the first recorded case of extracranial-to-intracranial bypass in an infant, doctors can give the family few answers on what the future holds.

“All the unknowns scares the hell out of us,” said Berry. “We just take it day by day.”

Harleigh could potentially have subtle issues as she grows, but the fact that she has bounced back so quickly has been amazing, said Klopfenstein.

“I suspect she will do very well," he said. "My philosophy is you hope and pray for the best, but be prepared for the worst. Thus far, Harleigh has demonstrated the absolute best.”

Leslie Renken can be reached at 686-3250 or lrenken@pjstar.com. Follow her on Twitter.com/LeslieRenken, and subscribe to her on Facebook.com/leslie.renken.