Doctors battle to save life of mathematician David Kazhdan, knocked off his bike in Jerusalem.

Israel Prize winner David Kazhdan, 67, was severely injured Sunday when he was hit by a truck while riding his bike in Jerusalem.

He was taken to Hadassah Hospital in Ein Kerem, where doctors were trying to stabilise his condition Sunday night.

"He is in very serious condition and the medical team is continuing its efforts to save his life," hospital spokeswoman Rachel Goldblatt said.

The driver who struck Kazhdan didn't stop and was not immediately located. Police set up checkpoints in the area near the accident and at the exits to Jerusalem in an attempt to catch the driver.

Kazhdan's son, Eli, was riding ahead of him when the incident happened. The two were on their way back from a trip to Beit Shemesh.

"I was riding in front of him, so I didn't see the accident itself," Eli said. "I heard the crash, and when I looked back, I saw my father lying on the ground. I didn't manage to see the truck, because my focus was on my dad. This work I leave to the police."

Kazhdan was born in Moscow and moved to the US in 1975. He immigrated to Israel in 2002 and won the Israel Prize for mathematics and computer science in 2012. He is currently a professor of mathematics at the Hebrew University in Jerusalem, professor emeritus at Harvard and a member of the National Academy of Sciences.

He lives with his wife in Jerusalem and has three children.

A medical team is fighting for the life of Professor David Kazdhan, winner of the 2012 Israel Prize for Mathematics and Computer Science.

Israel Prize winner Professor of Mathematics, David Kazhdan, is fighting for his life - after being knocked down in a traffic accident on Sunday morning.

Professor Kazdhan was hit by a tractor trailer while riding with his son. The driver did not stop at the scene of the accident.

Kazhdan, Professor of Mathematics at the Hebrew University in Jerusalem, received the prestigious Israel prize in 2012 in recognition of his important contributions to group theory, a cornerstone of mathematics with applications in fields such as physics, quantum theory and computer science. The awards committee described him as "one of the world's leading mathematicians in recent decades."

"My father rides regularly, despite his age," Kazhdan's son Eli told Israeli newspaper Yedioth Ahronoth, "he's an excellent cyclist."

He and his father were about to complete a 70km trail, in preparation for a 100km ride, when the accident took place.

"We left Jerusalem to ride to Bet Shemesh and back. I rode ahead of him, but when we were near to home, at around 11 am, I heard the noise of something hitting a bicycle. I turned around and saw him lying on the ground."

Eli said that the Magen David Adom emergency ambulance service and police arrived at the scene very quickly after the accident. "I trust the police will do their work and catch the offending driver ... who didn't even stop to help," he said.

Kazhdan, a father of four and grandfather of four, was born in Russia and in 1975 moved to the USA taking a post as the Head of Mathematics Department at Harvard University.

In 2004, Kazhdan and his family emigrated to Israel, where he has was appointed full professor at the Hebrew University - receiving international acclaim for his research.

"All of the family are here at the hospital and we are praying for him," Eli added, "his condition is very serious and we hope that he recovers fast and returns to himself."

Last week, eleven year old Oren Ben-Baruch was killed close to the same site of the accident when he was riding his bicycle and was hit by a truck.

Prof David Kazhdan remains in serious condition'; "We're looking to see why he didn't turn himself in," says Police spokesman.

The man driving the truck that allegedly struck internationally recognized mathematician and Israel Prize laureate David Kazhdan in the capital Sunday, rendering him in serious condition, was found and arrested by police Wednesday night.

According to police spokesman Micky Rosenfeld, an intensive investigation by the Traffic Police uncovered the location of the unidentified driver, who is in his 30s and works at a moving company.

Rosenfeld said Thursday that the driver will remain in custody pending a further investigation into why he fled the scene of such a serious accident.

"We're looking to see why he didn't turn himself in," Rosenfeld said.

Kazhdan remains hospitalized in serious condition at Hadassah University Medical Center in Jerusalem's Ein Kerem, after being struck by the truck while riding his bicycle in the capital Sunday morning.

At the time of the accident, Kazhdan was biking with his son from Beit Shemesh, police said.

Kazhdan's son, Eli, told police he was riding in front of his father when the accident occurred and did not see what transpired.

"I heard the crash, and when I looked back I saw my father lying on the ground," he said.

"I didn't manage to see the truck because my focus was on my dad."

Kazhdan was born in Moscow in 1946 and moved to the United States in the mid- 70s. He made aliya in 2002, and has since resided in Jerusalem with his wife and three children.

In 2012, he received the Israel Prize - Israel's highest honour - for mathematics and computer science, for his contributions to group theory.

Kazhdan was described by the award's committee as "one of the world's leading mathematicians in recent decades."

He currently works as a professor of mathematics at Hebrew University, is a professor emeritus at Harvard and a member of the National Academy of Sciences.

When on 6 October World-renowned Mathematician Prof David Kazhdan was run over by a truck while biking with his son, Eli, in Jerusalem, "his condition was so dire that in many medical centres in the world he wouldn't have been revived," relates Prof Yoram Weiss, Medical Director of the Hadassah Medical Center.

Now, four months later, thanks to specialised treatment at Hadassah, Prof Kazhdan is beginning physical therapy at Hadassah-Mount Scopus, as a prelude to returning home. "When he woke up, he said he'd heard music," his wife, Helena, remembered. "Now I understand why." Volunteer musicians had serenaded him while he was in the Intensive Care Unit.

The Musicians are Haverut organisation employees who work in different hospital departments to help patients dealing with the hospitalisations and recover with Art, music, spiritual care and more. They returned to provide Prof Kazhdan with a musical send off, this time performing a melodic rendition of Psalm 121, "I lift my eyes to the hills, from where I receive my help."

This past October, David Kazhdan, world-renowned mathematician, Talmud scholar, and biker was run over by the wheel of a tractor-trailer while bicycling with his son. He was brought to the Hadassah Medical Center's Trauma Unit close to death.

Prof Avi Rivkind, head of Trauma, saved his life by giving him an expensive medicine that is ordinarily not provided to a patient in Mr Kazhdan's situation. But, as Prof Rivkind explains, "You can't argue with success."

Exactly a year ago, on a sunny fall Sunday of 6 October, Israel Prize winner Professor David Kazhdan was on the last stretch of a 44-mile bike route together with his son Eli Kazhdan - CityBook CEO and former ministerial aide. Father and son had been riding together for years, and this morning's route from Jerusalem to Beit Shemesh and back was just a practice for an upcoming 50-mile cycling competition. Sunday morning is always a good time for bikers, when traffic is relatively accommodating. The duo had already pumped up the miles-long mountain that snakes from the Beit Shemesh valley to the capital and were heading home, when Eli - riding about 50 yards ahead of his father - heard a crash and the grating sound of twisting metal.

"I knew instinctively what had happened, and a quick glance over my shoulder told the whole grisly story: My father lay unconscious and contorted on the concrete next to his mangled bike."

No vehicle remained on the scene to take responsibility. But police later located the driver of the hit-and-run semitrailer - an employee of a moving company - who claimed he continued driving because he didn't notice the professor pedalling ahead of him even as he knocked him off his bike to the side of the road.

Professor Kazhdan was soon whisked off by ambulance to Hadassah Ein Kerem Hospital's trauma centre, where doctors began fighting for his life but - with a shattered pelvis, multiple leg fractures, and a severely wounded back - didn't give much hope for the 67-year-old mathematical genius' chances of survival.

One year later, Professor Kazhdan may not be running marathons, climbing mountains, or even pedalling down the block, but after nearly a year of paralysis, he's begun to hobble along on his own two feet, defying the dire predictions of therapists and physicians. It's his tenacity, determination, and will of steel - qualities that helped him survive the Russia of the KGB, embrace a life of Torah and mitzvos, and rebuild his life in the US and then in Israel - that helped him rally again, this time in what's been the most difficult test of his life.

Minutes after the accident, the media was already abuzz with the news that the Hebrew University mathematics professor and Israel Prize laureate was critically injured in a hit-and-run. Meanwhile at Hadassah, the doctors were trying to stabilise him. "He is in very serious condition and the medical team is continuing its efforts to save his life," announced the hospital spokesman that night.

Professor Kazhdan himself doesn't remember a thing of the accident. He lost consciousness as soon as the truck hit him, and he woke up nine days later.

"When I awoke I tried to understand what was going on," he tells Mishpacha a year later, sitting in his study of floor-to-ceiling bookcases with his walker at his side. "I realised of course that I was in the hospital. But it took me a month to really internalise that I'd been seriously injured in an accident."

His family, however, knew every breath was a fight for life and kept a round-the-clock vigil. Kazhdan, who is considered one of the leading mathematicians in the world today, had sustained severe injuries to his limbs, his legs, his back, and his ribs. Yet when he finally woke up and learned of the severity of his injuries and his paralysis, he didn't recoil.

"I preferred not to know too much," he says. "When I realised what had happened I decided not to ask too many questions. If the doctors would tell me something, I listened. I am not a doctor and I didn't want to overload myself with painful information."

His main consolation was the realisation that his head had not been affected. "It took two months, but I could finally rest assured that my brain was intact," he smiles. "And that's the main thing. Because without my head, I would be finished. As long as my brain still worked I knew I'd make it."

"My father has one prominent trait - stubbornness," says his son Eli Kazhdan who, as CEO of CityBook Services and former chief of staff in both the Ministry of Industry and Trade and the Ministry of the Interior, has displayed much of that goal-oriented drive himself. "We knew that if his body would survive those first days, he would make it. We were with him around the clock, including his 94-year-old mother. She never left his side. She told us that when he was born a preemie, two months early - in Moscow in the 40s - the chance of a preemie surviving was small. But he survived. She kept saying that he would survive now the same way he survived then."

After four painful months in the hospital, Professor Kazhdan was transferred to the rehab centre at Har Hatzofim. "When Professor Kazhdan came to us, he needed full-time care and support," says rehab director Dr Isabel Schwartz. "He needed assistance 24 hours a day for the most basic functions, with a near total lack of mobility in the lower part of his body. But he posted goals for himself and never flinched. I also give a lot of credit to his wife. She felt the pain with him, displayed an incredible solidarity. We were all taken aback that someone so seriously injured would leave rehab the way he did."

But he did leave, walking on his own two feet. It's not normative walking, or the kind of walking he was used to in the past. It's more like a shuffle, with the aid of a walker. But his legs, which had been shattered in the accident, are working again.

"Throughout the treatment in the trauma unit, in intensive care, in the surgery wards, and through the rehab, Professor Kazhdan stayed motivated," Hadassah's director of orthopaedics, Dr Meir (Iri) Liebergall, told Mishpacha. "Even through the doubts - and there were lots of doubts. He had to face a lot of pain and to muster up huge reserves of physical and emotional energy. It's not something to be taken for granted. Every person wants to get better, but not everyone succeeds. Professor Kazhdan crossed all the bridges, and has come a very long, complex, but wonderful way."

Professor Kazhdan forces himself to walk two hours every day now, but it's no marathon. He uses a walker, and sometimes an aide. But he's focused on the day he can go back to the lecture hall, back to face a room full of students instead communicating via computer.

"We're only halfway though," says Dr Schwartz. "Our goal is to restore him to the maximum that he can. We have a lot of work yet, but I believe he will be able to get back to the life he loves, to his work, and the students who are waiting for him."

My mobile phone rang early one Sunday morning in October 2013. "It is Helena calling from Moscow," the voice said. "My husband, David, was run over by a tractor-trailer while riding his bike in Jerusalem. He is in very critical condition. I am returning to Israel." David's son Eli called later and, whispered, in a broken voice, "We are losing him. The doctors at Hadassah Hospital can't control his massive bleeding."

Getting that phone call - the thought of losing David was devastating and paralysing.

On Monday, 7 October 2013, David's son Eli emailed: "... the bleeding is under control, the CT of the head shows that all is good up there ..." Days later, he wrote: "With some trepidation, it seems that we have indeed turned a very important corner - and my father's condition can be carefully and optimistically defined as 'serious but stable.'"

With his wife's love and dedication, and the steadfast care and support of his doctors, family, friends, and colleagues worldwide, against all odds, David survived.

Weeks later, David regained consciousness. He was still gravely ill and in the ICU, but we resumed our learning. I had forgotten where we had left off in our studies, but David remembered exactly what we were up to. David had a turbulent recovery course that required many surgeries and close to a yearlong hospitalisation. And, still, we kept studying.

Three years after this horrific accident, David continues to be challenged by the physical consequences of his injuries. But he courageously perseveres.

Perhaps our most dramatic learning session took place months after David's discharge from the hospital. The Skype call that David initiated was of poor quality, with a very noisy background. "You must have many guests?" I said. "No," he answered in an unruffled voice. "I am in the emergency room of Hadassah Hospital, being evaluated for high fever and sepsis and I have a few minutes now. Let's learn." And we did.