There's renewed hope for the 100 Kiwis who are diagnosed with hydrocephalus, or fluid on the brain, every year.
The Kiwi inventors of a world-first monitor for the condition hope to take their invention worldwide.
For 50 years, hydrocephalus has been treated by inserting a tube from the brain down to the stomach to drain the fluid.
But more often than not that shunt will go wrong - with potentially fatal consequences. In fact, it can kill you in a day unless you can get to hospital.
That was a reality the parents of Will Muir lived with for the five-and-a-half years he lived.
"In personality he was very lively and spirited and was generally a very happy kid," said his father, Jeremy Muir.
His mother Catherine Burnet agreed: "He was nice to have around, he was a happy chappy."
Will was happy but not healthy. At three months, he was diagnosed with a brain tumour that also caused hydrocephalus which blocked the plumbing in his brain. It meant surgery then the insertion of a shunt to ease the pressure but which failed multiple times with little warning.
"You'd realise there was something going on and have to drop everything and go to Starship (the Auckland children's hospital)," said Burnet.
"The key medical issue is that you can't check whether the shunt is working or not without actually a full anaesthetic, opening it up, taking it out and having a look," said his father.
But, given that 70 percent of the time symptoms like colds or headaches are merely false alarms, the medical caution is understandable.
But a new invention can detect what is or isn't a threat to life when a shunt fails, of which half fail within two years.
Dr Sarah-Jane Guild and her University of Auckland bio-engineering team believe they've found a solution, given that half of all shunts fail within two years.
"They should be able to avoid those false alarms. We can't do anything about the shunt failing, the shunt blocking, that's always going to do that," she said.
"That's not what we're trying to do. But we want to be able to tell them confidently what the pressure in their brain is and whether they need to respond or not."
The answer lies in a tiny glass sensor inserted into the brain alongside the shunt. It is just two centimetres long but contains all the electronics to be able to measure pressure and transmit it to an app on a phone, which in turn can be monitored daily by surgeons.
Any figure up to 20 means you're fine. But Dr Guild says if it rises between 25 and 50 it would trouble the surgeons.
"We haven't been able to do this before. This is a world first," Dr Guild said.
"The only way to measure pressure in someone's brain is to drill a hole and put a catheter straight in it. So at the moment you can't do this at home, you can only do that in the hospital."
The sheep in the trial have been living with the sensor implanted in their brain for up to a year.
"These sheep are really happy, they live their best sheep life," said DrGuild, who points out that there are strict regulations around working with animals.
The team has to apply for ethical approval from their local Ethics Committee. The surgery is sterile and uses anaesthesia, pain relief and antibiotics, just as would happen in a veterinary clinic.
The devices are now ready for testing on humans in the second quarter of this year. Ten adults and 10 children who need surgery will also have the device implanted. There are also hopes of taking the invention to the American market with approval from US authorities.
The move meets with the approval of Muir and Burnet.
"What we would dream about when we were going through it would be some kind of device where we could check if the shunt was working or if the pressure was building without having to have an operation to test it," said Muir.
Will Muir lived a full life. He was sociable, musical and playful. This invention would not necessarily have prolonged his life but it would have helped ease the family's frustrations when their instincts told them something was wrong but surgeons held back from intervening because they were waiting for the right clinical moment to make their move.
Burnet said their instincts were right on shunt failures 100 percent of the time.
"If you could wave your magic wand and tell beforehand then that kind of to-ing and fro-ing would cease," said Burnet.
Many in the New Zealand startup community have invested in the sensor, including Jeremy Muir himself.
"We were keen to put our money where our mouth is, so to speak, and recognising the experience that had happened to us put something toward helping out others. And it is a great piece of New Zealand scientific development," he said.
The sensor itself may have other uses. It could be adapted to measure lungs and hearts.
