Scientists Use 3D-printed Bone Implants to Repair Spines and Skulls

25/01/2017

Although we don’t think of it as such, bone is an organ of the body that, just like the heart, liver, and lungs, is composed of many types of tissue and performs many different functions.

When extensive damage disrupts these tissues, like in a bone fracture, they can fail to heal properly and pose a significant risk to the patient. In these cases, the surgical technique of bone grafting is used to provide a scaffold for new bone to regenerate and bridge the void.

Typically, surgeons use bone from other parts of the patient’s body or implants made from a mixture of synthetic and natural compounds. These methods are far from ideal, not least due to our limited supply of spare bone and the brittleness and lack of malleability of implants.

Attempting to make these issues a thing of the past, scientists at Northwestern University have developed Hyperelastic ‘Bone’, a new biomaterial that is highly versatile, scalable, and surgically friendly.

An on-demand repair kit for our bones

“Our vision is to have 3D printers in a hospital setting where we provide the hyperelastic bone ink, so surgeons can make individual implants within 24 hours… You could make off-the-shelf, or patient-specific implants using scans from patients,” —Ramille Shah at Northwestern University in Evanston, Illinois

The results, published in the journal Science Translational Medicine and described as “quite astounding”, show how the scientists successfully repaired spinal injuries in rodents and the skull of a monkey.

One major benefit of the biomaterial is, unlike real bone grafts, it requires no added growth factors to spur bone regeneration. Also, as it made from a binding polymer called PLGA and hydroxyapatite, a mineral found naturally in bone, it is ultra-flexible, allowing surgeons to cut and mould it into the right shape during surgery.

“Even when it’s deformed or squeezed into a space, it still maintains high porosity, and this is also very important for blood vessels to infiltrate the scaffold so that it can further support cell and tissue growth.” —Ramille Shah

Iain Hutchison, a maxillofacial surgeon at St Bartholomew’s Hospital in London explains the hyperelastic bone is actually a matrix. It is because this matrix so closely resembles natural bone in mineral content and pore structure that it kick-starts the body’s natural processes into action, mistaking the implant for incomplete bone and refilling the area with new tissue.

“It’s terrific, and a great advance,” says Iain Hutchison. Shah believes it could reach the clinic within the next five years.