A toddler in China has made medical history after becoming the first person in the world to have her entire skull reconstructed by 3D printers.

Known as the 'big-head baby', Han Han, 3, had a rare condition which made her head grow to four times the normal size.

This put her at risk of going blind and even of having maggots infest her brain.

However, yesterday she underwent 17 hours of surgery - and is now expected to make a full recovery, People's Daily Online reports.

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Unwell: Chinese baby Han Han, 3, had a condition which made her head grow to four times the normal size

Congenital: The toddler was born with hydrocephalus - a build up of fluid on the brain

Severe: Han Han's condition was so advanced that the fluid filled 85 per cent of her brain - making her skull three-four times larger than it should have been, measuring around 20cmx20cm

The toddler was born with hydrocephalus - where a build up of fluid occurs on the brain.

But her condition was so advanced that the fluid filled 85 per cent of her brain - making her skull three-four times larger than it should have been, measuring around 20cmx20cm, 3dprint.com reports.

The danger with hydrocephalus is that the excess fluid puts pressure on the brain, damaging it.

Indeed, before undergoing the pioneering surgery, Han Han had developed medical problems such as a thinning skull and poor blood supply.

And because her head weighed more than half of her body weight, she struggled to lift it from the pillow, so had been bed bound for nearly a year.

After her family was warned her skull could rupture at any moment, it was agreed urgent action was needed.

But her they were unable to afford the complex treatment the toddler needed.

Doctors had originally calculated it would cost 400,000 – 500,000 Chinese Yuan (approximately $64,000 – $80,000).

Thanks to donations from family and friends, around 100,000 yuan was collected.

But when Han Han's mother left when she was a year old, it was down to her father Chen Youzhi to earn 100 yuan per day to buy the anti-inflammatory drugs she needed.

Pioneering: But she has now made medical history after becoming the first in the world to have her entire skull reconstructed by 3D printers

Surgery: Yesterday, Han Han finally underwent the life-changing procedure at the Second People's Hospital in central China's Hunan Province

Relief: During the operation, Han Han's scalp and skull were removed. Her brain was then repositioned and the huge volume of excess fluid drained away. To her family's relief, he operation was a success (Han Han is pictured with her aunt)

Progress: As Han Han continues to grow, the titanium implants will become surrounded by her own bone, strengthening the top of her skull. Doctors say the toddler should make a full recovery

Eventually, it was the kindness and generosity of strangers that paid for the toddler's treatment through online donations.

Yesterday, she finally underwent the life-changing procedure at the Second People's Hospital in central China's Hunan Province.

There, surgeons used 3D printing technology to create a titanium alloy skull and successfully set it into Han Han's head during a 17-hour operation.

Prior to surgery, medics had used CT scans and 3D data to create three titanium mesh skull implants which combined, would replace the entire top portion of the toddler's skull.

During the operation, Han Han's scalp and skull were removed. Her brain was then repositioned and the huge volume of excess fluid drained away.

To her family's relief, the operation was a success. After surgery, Han Han immediately opened her eyes and was breathing unaided before being transferred to ICU for recovery, reports 3dprint.com.

As she continues to grow, the titanium implants will become surrounded by her own bone, strengthening the top of her skull.