Every day, lives are saved through surgery. This week the Herald takes a look at some of our country's most extraordinary operations - from a thumb being replaced with part of a toe, to part of a bike being removed from a young girl's groin. Health reporter Emma Russell reports on some of the remarkable stories.
Tessa Binns was just 4 months old when surgeons cut open her scalp and removed parts of her skull.
The baby's brain didn't have room to grow and without an "unbelievable" neurosurgery she would have struggled to walk or talk properly.
During a three-hour operation, surgeons carefully pulled back her scalp - which at that age is the consistency of cardboard - before removing parts of her skull and reshaping her head to allow her brain to grow normally.
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Tessa's mum Jo Binns said she could not thank the surgeons enough for giving her baby the chance to develop normally - something that might not have happened if she hadn't noticed her daughter's "wonky head" while bathing her at 2 weeks old.
To explain what was wrong, Tessa's plastic surgeon Charles Davis said to imagine you had a balloon and half blew it up, then put sticky tape all down one side and kept blowing it up - it's going to bulge out somewhere else.
"That's what was happening to Tessa's brain - it was growing lengthways because it was being restricted widthways."
A CT scan confirmed it was a condition called sagittal craniosynostosis, which affects roughly one in 2500 babies, and causes her skull bones to join prematurely.
Left untreated, it can result in seizures, blindness and developmental delays.
Davis and neurosurgeon Agadha Wickremesekera performed an operation which involved peeling back Tessa's scalp, making several cuts in the skull before removing parts of the bone. Her head was then reshaped and reattached using dissolvable plates and screws.
"Essentially what we want to do is give the brain plenty room to grow, which is crucial in the first two years," Davis explained to the Herald.
Normally, a baby's brain is about 70 per cent the weight of an adult brain by the age of one year. By two years it's about 80 per cent and by five years it's usually fully developed.
Though the diagnosis was terrifying, Binns remained positive throughout the surgery and was relieved when her daughter woke up from the operation smiling like she always does.
"The surgeons were just amazing, we are so grateful to them.
"If she hadn't had the surgery she would have had developmental issues with walking, talking and probably all of her other milestones," Jo told the Herald.
The surgery is funded by the Government but the Ministry of Health was not able to say how much it cost.
Tessa is recovering well. Her mum says having the reassurance that her baby's brain will develop normally means the world.
• It's a birth defect resulting in premature closure of bones in the skull restricting the growth of the brain and often resulting in an abnormal head shape.
• Left untreated, it can result in seizures, blindness and developmental delays.
• The condition affects one baby in about every 2500, which is about 30 babies a year in New Zealand.
• Surgery is performed to release the fused skull bones and to reshape the head.