A spine model implanted with a 3D-printed artificial axis is displayed at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

A medical staff member displays a spine model implanted with a 3D-printed artificial axis at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

Chinese doctor Liu Zhongjun poses for pictures with a spine model implanted with a 3D-printed artificial axis, at Peking University Third Hospital in Beijing, August 14, 2014. Liu has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

Chinese doctor Liu Zhongjun gives an explanation of the 3D-printed artificial axis he has successfully implanted into the spine of a bone cancer patient at Peking University Third Hospital in Beijing, August 14, 2014. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

Combination picture of a spine model, a spine model implanted with a traditionally used titanium tube, and a spine model implanted with a 3D-printed artificial axis (L-R), are displayed at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Pictures taken August 14, 2014. REUTERS/Jason Lee 

A spine model is displayed at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

A spine model implanted with a titanium tube is displayed at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee 

A spine model implanted with a 3D-printed artificial axis is displayed at Peking University Third Hospital in Beijing, August 14, 2014. Chinese doctor Liu Zhongjun has successfully implanted an artificial axis produced by a 3D printer into the spine of a bone cancer patient. This was the first time that an axis produced by 3D printing had been implanted into a patient, according to Liu. Normally, a diseased axis would be replaced by a standardised, hollow titanium tube, said Liu. Picture taken August 14, 2014. REUTERS/Jason Lee