Conjoined twin boys have been successfully separated after a remarkable twelve-hour operation using 3D printer technology.

Medics in China separated five-month-old twins Yu Ce Yuan and Yu Ce Xiang - known as James and Harley - who were joined at the abdomen.

They the technology to make models for a virtual operation, sending data from the twins CT and MRI examinations to a 3D printing company to build two models of the conjoined body parts.

Parents Yu Dang and Zhou Li travelled, both 20, travelled more than 1,000 miles from their home in the rural, mountainous Guizhou province to Children's Hospital of Fudan University in Shanghai for treatment.

Five-month-old twins Yu Ce Yuan and Yu Ce Xiang - known as James and Harley - were joined at the abdomen

Surgeons used the models to develop a plan for the operation, which involved separating the liver and pelvic bone before moving onto the intestines.

A urology team then worked to place the babies' bladders back inside their bodies before orthopaedic surgeons took over to reconstruct there pelvic cavities.

Finally the surgeons fitted colostomies and closed all incisions before the boys were taken to intensive care.

Mother, Zhou Li, said: 'In the beginning there was nothing abnormal. It was only when I had the baby that I realised they were conjoined twins.

'It was very painful and difficult. I felt like I was soon to die, like I couldn't breathe and there was a lot of blood.

'I never considered giving them up. I gave birth to these children, they're my flesh and I wouldn't give them to anyone else.'

Surgeon, Dr Zheng Shan, said it was an unusual case with about one in 30,000 being conjoined twins.

He said the hospital - which was the first to use the 3D printing technology in China last summer - had dealt with nine cases of conjoined twins.

James and Harley were born conjoined with this graphic demonstrating their structure before surgeons operated at the Children's Hospital of Fudan University in Shanghai, China

They used 3D printing technology to show exactly how the twin boys were joined at the pelvis, giving doctors a better idea of how they could separate the pair prior to surgery

Conjoined twins Harley and James photographed with their parents Yu Dang and Zhou Li and their grandmother, prior to surgery to separate them

But he said this was the most complicated case he'd dealt with and said further surgery would be needed.

'The surgery is important for two people's lives and their quality of life, urination, defecation and the bodily functions they will use in the future,' he said.

I never considered giving them up. I gave birth to these children, they're my flesh and I wouldn't give them to anyone else Zhou Li, 20

'Their makeup is extremely complicated, they only have one anus, four urethra and four bladders - their structure is incredibly complicated.

'Regarding protecting their lives, I'm positive. But to ensure two lives are intact, in terms of quality of life, normal functions like giving birth - I think that's more difficult.

'The surgical procedures will be long, perhaps the children will have to go two or three surgeries.'

The operation, on February 24, was made possible by the generosity of strangers around the world who donated more than £40,000 to cover its costs..

The couple, from one of the poorest areas of China, had been unable to afford scans before the birth of the twins and the delivery came as a shock to the family and doctors.

In parts of China there is a high abandonment rate of children with birth defects, but the couple refused to give up on their babies.

The new parents borrowed money to cover the twins' initial medical expenses but were discharged after being unable to pay the operation fee.

Doctors examine the conjoined twins prior to the major surgery in Shanghai carried out last month

Medics in China worked tirelessly to separate five-month-old twins Yu Ce Yuan and Yu Ce Xiang to the relief of their 20-year-old parents. Charity Love Without Boundaries helped to raise the money for surgery

The twins' father spoke of his fears that he would have to choose between his babies' lives.

He said: 'At the beginning we thought the surgical fee was too expensive, then we were scared we'd have to choose between one and the other.

'Our hopes are that after the successful surgery their living conditions will be improved.

'We are thankful towards each kind-hearted person's help. We are very grateful for their support,' said Yu Dang.

The family were saved by Love Without Boundaries, a charity for orphaned and impoverished children, and after only a month of fundraising sufficient money had been raised.

Last week the boys were taken off their ventilators and doctors are thrilled with their progress.

Their mother said she hoped the twins would grow up to become doctors themselves.

Amy Eldridge, chief executive officer for the charity said the worldwide support for this cause had been 'truly humbling'.

'As soon as we heard their story we pledged to help, but it only became possible because complete strangers gave from their hearts.

'That's love in action at its finest,' she said.

One of the twins photographed after their operation at the Children's Hospital of Fudan University. Doctors said both were doing well but would need further operations in the future