24 Feb 2024

Pioneering kiwi research for hydrocephalus patients

From The Detail, 5:00 am on 24 February 2024

Work being done on a farm outside of Rotorua has the potential to change, and save, the lives of hundreds of Kiwis and potentially millions globally

Dr Sarah-Jane Guild

Dr Sarah-Jane Guild with the diagnostic device Photo: Sharon Brettkelly

Just outside of Rotorua is a sheep farm that looks like any other. Until you climb the stairs of a big shed and peer inside a small room that is a surgery, where the sheep are operated on.

Look closely at the sheep in the pens and you might see that they have small scars on their heads.

They are the pioneers of research that is set to change - and save - the lives of hundreds of Kiwis and potentially millions of people around the world who have the brain-swelling condition hydrocephalus.

The diagnostic device at the centre of this research is a tiny implant in the brain and a wireless wand that is held over the head. It's been successfully tested on the sheep and is about to take the momentous next step to human trials, first on adults and then children.

It is the result of 20 years of research by a team at Auckland University's Bioengineering Department and the university's medical technology company, Kitea Health. If the human trials are successful, the device could be in New Zealand clinics and used by patients with hydrocephalus next year.

A key part of the process is the welfare of the sheep, overseen by the university's vet and animal welfare officer, Dr Jodi Salinsky. 

"We take great, great, great pains to ensure in the ethics applications that the animals are well cared for their whole lives, that we respect them and that we treat them as well as they can possibly be treated," says Salinsky, who is keen to emphasise the team's deep feelings for the animals.

Dr Jodi Salinksy, Auckland University's animal welfare officer

Dr Jodi Salinksy, Auckland University's animal welfare officer Photo: Sharon Brettkelly

"It's really exciting," research team leader Dr Sarah-Jane Guild tells The Detail. "To be so close to actually being able to place this in a person who has hydrocephalus is incredibly exciting."

Hydrocephalus is a build up of cerebral spinal fluid and often develops in the first two years of a child's life, but continues into adulthood, or can start in adulthood. 
According to the university, every year 100 New Zealand children are diagnosed with the condition which can be congenital or because of injury or cancer. Without drainage it can be fatal within a few days.

For the last 50 years a lifesaving shunt has been used to drain the fluid into the stomach, but the shunt's tube blocks easily, with about half failing in two years and about a third failing in six months in children. Symptoms of failure include irritability, headaches and vomiting, as the pressure builds up inside the brain because the fluid isn't draining properly. 

Researchers say it's not a matter of if it will fail, but when. 

At a table in the sheep shed, Guild shows The Detail how the small-tubed shunt is inserted into a model of a human skull. The silicon tube carries fluid from the brain down into the stomach where the fluid drains out. 

If the shunt is not cleared within 24 hours the patient can die. But the only real way of knowing if the shunt is blocked is by drilling a hole in the head - a drastic procedure that can only be done in hospital, says Guild.

But that is all about to change thanks to the research that has included the trials on the sheep at Auckland University-owned Ngapouri Research Farm. 

It couldn't have been done without the sheep," says Guild as she waves a table tennis bat-sized wand over the head of a sheep.

"Absolutely not. No one's going to let us take something to clinic and use it in a human, in a child, before we have shown that it's safe to do that and this is the only way."

Sheep are used because their brain is a good size, their basic physiology and mechanics of the spinal fluid are similar to humans, they are robust animals and reasonably compliant, she says.

The wireless wand she passes over the sheep's head powers the sensor implanted in its brain to take a measure of intracranial pressure, or brain fluid.

The researchers compare the readings over time to make sure the sheep are stable and not impacted by the animals' reaction to the sensor or to external factors.

Guild says the results are "gloriously boring" which means they can now proceed with the human trials.

"The idea is that we will place this pressure sensor when we place the shunt tube, and then patients and their families will be able to measure the pressure at home."

The device will offer peace of mind for families, and reduce unnecessary trips to the hospital. 

"Seventy percent of the time patients turn up at the emergency department with symptoms that might suggest their shunt is failing and they are sent home because their shunt is not failing, it's something else," says Guild. "That's fine if you live 20 minutes from Starship Hospital, not so good if you live anywhere else where you don't have access to neurosurgery."

The device would have made a huge difference to the lives of Catherine Burnet and Jeremy Muir, whose little boy Will had hydrocephalus. The year baby Will was diagnosed with a brain tumour and hydrocephalus, the couple had to make frequent trips to Starship for shunt revisions.

Catherine Burnet and Jeremy Muir

Catherine Burnet and Jeremy Muir Photo: Sharon Brettkelly

"Each time it was the same story. We would go in, wait in the emergency department to be transferred to a ward, once we'd been seen by a doctor who ascertained that we needed to go to a neurological ward and then the people at registrar consultant level would wait for the situation to declare itself," says Burnet.

That meant waiting for symptoms such as vomiting, rolling eyes and headaches. Burnet remembers constantly measuring Will's head, looking for signs of change that could indicate a fluid buildup. 

The first year was made more difficult by surgery to remove a tumour and chemotherapy. Will died when he was five and a half.

"I wouldn't wish that on anybody but I wouldn't change it for us because it was a very positive experience to have him in our lives," says Burnet.

The couple would often "dream" about a device that they could wave over Will's head that would detect whether or not the shunt was working.

"Certainly at that time we had no idea how technically that could be done," says Muir.

They have shared their experiences with the researchers and invested in the development of the device.

"We look forward to the start of human trials at Auckland Hospital and Starship and that will really hopefully demonstrate that this is something that's going to work, not just on happy sheep," he says.