In a world’s first, doctors successfully resect 5 vertebrae with a 19cm 3D printed spinal implant

In a world’s first, doctors successfully resect 5 vertebrae with a 19cm 3D printed spinal implant

news08

The Peking University Third Hospital in Beijing, China is building up a reputation for groundbreaking medical procedures involving 3D printed implants. Two years ago, they became the first hospital in the world to implant a 3D printed vertebrae, and they have now completed an even more remarkable feat. Just a few days ago, the hospital’s surgeons removed five sections of a patient’s spine – all affected by malignant spinal tumors – and replaced them with 3D printed implants, becoming the first hospital in the world to replace such a large segment of the spine.

This feat is especially remarkable because the patient in question, Mr. Yuan, was faced with an impossible situation. Suffering from chordoma, Mr. Yuan’s spine was in such a terrible state that up to 19 centimeters had to be removed completely – including thoracic sections 10, 11, and 12 and lumbar sections 1 and 2. While removal provided the only chance of saving his life, very few doctors in the world would even dare to remove such a large portion of the spine. Problematically, there are no ready-made solutions to replace that such a large section. With no precedent existing for the large titanium mesh that would be necessary, the doctors settled on a remarkable 3D printing solution.

During the surgery, which took place in the early hours of June 12th at Peking University Third Hospital’s orthopedic ward, surgeons implanted multiple 3D printed thoracolumbar implants over the 19 cm long section of the spine. These completely replaced the five resected vertebrae, an exciting medical first.

As surgeon and Professor Liu Zhongjun revealed, the surgery itself is very rare. Despite having obtained CFDA certificates for 3D printing artificial vertebrae and studying them for surgical purposes, they were unsure what to do in a situation where five vertebrae were resected. How can the implants be supported, and how can the important spinal cord, nerves and blood vessels in the spinal canal be kept intact when after removing such a large section, the spinal structure effectively ceases to exist and needs to be rebuilt. It was an unprecedented challenge.

Spine fixation can effectively be divided into two categories: on front and on the rear side. The rear side is the most accessible, and during surgery the specialists use the pedicle screw fixation technique to fixate spine segments to the lower and upper end of the remaining intact spine with metal rods. This should provide the patient with enough stability to get out of bed and perform basic activities.

But the big problem is on the front side. Traditionally, implants would be fixated by filling the titanium mesh with autologous or allogeneic bone material, which provides interbody support. Hopefully, the bone fuses together with the adjacent structures over time, providing a stable structure. However, that technique is not entirely suitable for a large structure reconstruction. If the titanium mesh shifts it could compress the spinal cord, resulting in paralysis. What’s more, the titanium mesh has a straight cylindrical shape, and does not correspond to the spine’s natural S curve. While not a problem for single vertebra replacements, they are not suitable for such large segments and no manufacturer produces them.

The surgeons were thus effectively left in no-man’s land, and turned to 3D printing. “We can use metal 3D printing technology, in accordance with the patient's anatomy, to create an artificial vertebral form that is similar in shape and length to the five sections that needed to be removed,” the professor explained. “Artificial vertebrae have significant advantages. Firstly, if placed between the adjacent vertebral bodies after the removal of lesions, it can form a reliable connection. Through 3D printing, it can be designed to provide optimal support, and we developed a structure especially suited for the patient’s back to greatly enhance the stability of the front and rear sections.”

The professor went on to argue that it’s a qualitative leap in terms of mechanical properties. “With such a fixation method, the patient can even get out of bed very early on into the postoperative process. The artificial vertebral body has a porous structure, that is shaped like a sponge and resembles a trabecular bone,” he explained. “With this bone, adjacent vertebral bone cells can grow into the structure and eventually blend together through osseointegration.”

The 3D printed artificial vertebral body received approval from the CFDA, China’s Food and Drug Administration, on May 6. The 3D printed implants were listed in the third section of orthopedic implants, which can be directly implanted and are placed under the highest level of supervision. The implant was co-developed by Peking University Third Hospital’s orthopedic department and industry partner Beijing Ai Kang Yicheng Medical Equipment. They previously gained CDFA approval for a co-developed 3D printed hip joint in 2015, the only other 3D printed implant with that level of approval.

According to the professor, 3D printing has become a life-saving solution. “Without it, we would have to tell patients a horrible truth: that we cannot find an ideal treatment method and that no surgical solution exists. This would be a huge tragedy for the patient, but 3D printing now enables custom implants and complete reconstruction opportunities. After the artificial spine is fixated in the body, the patient can return to normal life,” he said.

This was proven during the surgery for Mr. Yuan. After a six hour surgery, during which no complications occurred, the patient was moved out of the operating room. Having lost little blood and with his vital signs remaining stable, he didn’t even have to stay in the ICU and was moved back to the general ward immediately. Currently recovering, the prospects are good. It just shows what a custom 3D printed solution can contribute to medical care.