Medical practice

Woman gets artificial jawbone transplant

An 83-year-old woman has been implanted with the world’s first “3D printer-created jaw”. Using cutting-edge laser manufacturing techniques, doctors and metal experts were able to build up layers of titanium to form a custom metal jawbone to exactly fit her face. The metal jawbone was then inserted into her lower jaw, replacing a large section of bone that was destroyed by a chronic infection.

The technique of 3D printing has been used to build prototype products for some time, but in recent years scientists have begun experimenting with the medical possibilities offered by the process. In this case, a specialist metalwork company called Layerwise was able to translate 3D bone scans into a custom jaw. The company had previously used the process to make bone-shaped prostheses and dental implants. To make a full jawbone, the implant team had to overcome a number of challenges, such as how to encourage muscles to attach to the implant and how to incorporate the nerves necessary for normal movement of the jaw.

While 3D printing is still an experimental medical technique, scientists are currently devising ways in which they might use it to produce whole organs, which are either “printed” by sandwiching layer after layer of living cells on top of each other or created by building scaffolds for cells to grow on.

Why did the woman need a new jaw?

The woman had a condition called osteomyelitis, a type of damaging bone infection usually caused by bacteria or, less often, by a fungal infection. It can occur when infections in nearby skin, muscle or tendons spread to a bone, or when an infection spreads from another part of the body through the blood stream. Depending on the nature of the infection and the health of the patient, osteomyelitis can cause permanent damage to bones. The condition can be treated with antibiotics to get rid of the infection and prevent further damage, but sometimes surgery will be needed to remove dead bone tissue from around the site of the infection.

If a section of bone tissue is removed, surgeons can close the space by grafting in bone taken from elsewhere in the body or by inserting specialised filler materials that promote regrowth of the surrounding bone.

In this case, the patient had a progressive, chronic form of osteomyelitis which affected nearly her whole jawbone. This meant that she experienced permanent destructive changes which could not be treated by antibiotics alone. Because of the patient’s age, reconstructive surgery using conventional methods would have been risky. Therefore, her medical team decided to attempt to use a bespoke titanium-based implant to replace nearly her entire lower jaw.

What is 3D printing?

3D printing broadly encompasses a variety of different techniques. All the techniques involve using computers to knit together layers or particles of materials to form a new 3D structure. At present, doctors, scientist and technicians use 3D print technology to build implants out of metals, plastics and ceramics and are experimenting with making 3D structures using synthetic bone materials and even living cells.

It can have several advantages over traditional manufacturing techniques, most notably the ability to create highly accurate bespoke structures such as dental implants. In the case of the new jaw implant, the process offers the option to create a structure that can perfectly fit the dimensions and contours of the patient’s face. Given the complexity involved, using an off-the-shelf implant is not practical.

To create the implant, the manufacturer Layerwise used a type of 3D printing called “selective laser melting”. During the process, heat-producing lasers are focussed on a bed of metal powder so that particles are precision-fused to form a 3D structure. This process is different from traditional metalwork, in which a shape is created by starting with a solid block and removing metal, similar to sculpting. Instead, the 3D printing process allows a shape to be built by adding tiny, intricate layers of particles, much like building a structure, layer by layer, from microscopic building blocks.

Has it been used medically before?

Doctors have previously used 3D-printed metal implants for dentistry and small bone prostheses, but this was the first time it was used to make a full jawbone. The benefit is that these custom-made prostheses can be modelled and shaped to fit the unique structure of someone’s surrounding bones. The surgeons revealed that surgery to implant the jaw took less than four hours and that the patient could speak and swallow again the day after surgery. This rapid recovery of function is encouraging.

It is likely that this technique will be investigated by other surgical groups, but the current reports relate only to the treatment of a single patient with chronic bone infection. It is not yet known whether it could be successful in wider facial reconstructive surgery, for example following trauma.

What might it be used for in the future?

While there are no guarantees that experimental lab techniques can be turned into usable treatments, medical 3D printing has been a hot topic in the news in recent years.

For example, in November 2011, BBC News reported that a team of scientists from Washington State University had used “a bone-like ceramic powder” to make a bone-like material that acts as a scaffold for new cells to grow on. However, his experimental technique had not been used in people at the time of reporting.

Scientists are also looking at whether it is possible to use 3D printing to create important structures such as heart valves and even whole organs. A variety of systems is being tested in the lab, from creating 3D scaffolds for cells to populate to layering cells themselves.

Much of this cutting-edge technology is years away at the very least, but the possibilities are great and very exciting, as highlighted during a talk by Dr Anthony Atala at last March’s TED conference.

NHS Attribution