Hip Revision Model
Hip Revision Model
The development of new and cutting-edge materials goes hand in hand with new and cutting-edge processes, which is why Replica 3DM believes it is revolutionising surgery with innovative polymers and inert plastics using 3D printing.
Managing Director of Salisbury, UK-headquartered Replica 3DM Matthew Sherry spoke to TCT’s Rose Brooke in August about the company's leading work in the field of surgery. The company has been operating for around 18 months and uses patient data sent from NHS trusts, which is then transformed into digital 3D reconstructions to be 3D-printed for surgical guides.
Sherry explained that in the instance of a jawbone for example, the surgeon can then use the 3D-printed model to either pre-bend titanium plates, or they can use the model for pre-operative investigation. This allows them to rehearse the operation using a dummy, consequentially reducing theatre time, recovery time and the amount of post-op care the patient would then require. Moreover, by reducing theatre time, NHS Trusts are slashing costs.
This side of the business, according to Sherry, makes up 80 per cent of Replica 3DM's work, while the other 20 per cent centres around more commercial work such as architectural models.
The business has two Stratasys Objet 3D printers (Stratasys Objet24 and Objet30 Pro) that print using photopolymer acrylics, which, according to Sherry, maxillofacial technicians prefer because it retrains its structural integrity but can be drilled easily for plate fittings. Replica 3DM uses a VeroWhite material allowing for high-accuracy printing of up to 28 microns, while surgeons prefer this material visually because it looks more like bone. The team at Replica 3DM, however, believe VeroBlue gives the most pleasing results to the eye. In addition, Replica 3DM produces models in PLA, building models both in white PLA and in a Ninjaflex rubber material.
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Cranioplasty without implant
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Cranioplasty with implant
Before surgeons could use surgical guides produced to this degree of accuracy with real digital data, plate bending and other procedures were much more hands-on.
"There wasn't a solution other than going to the operating theatre, opening up the patient and trying to bend a piece of titanium plate there, switching between workbench and patient until it fit. It added about an hour to surgery" Sherry explained. "For pre-op, you used to have to rotate the image made from CT data on a 2D screen but the problem is, there's a lot of artefact with a CT and that can sometimes obscure the bone, whereas this gives you a real item in your hand. There's no comparison, really."
Working by hand cannot guarantee accuracy like 3D printing, ensuring surgeons only make the incisions they need to and have 100 per cent confidence the plate will fit. "It's revolutionised this sort of surgery," Sherry said.
"We've done a number of facial reconstructions where the mid-face from the upper teeth to just above the eye sockets where the patient has a bone deformity or has had a road traffic accident. What we do is make two models and the surgeon uses one to demonstrate what the patient currently looks like and then the second is used to make incisions so the bone is readjusted to demonstrate how the surgeon will do the surgery. It allows the surgeon to practice and know what they need to do in surgery and if they don’t get that first one right then they'll just work on the second model. It allows them to do reconstruction on a model rather than practicing on a patient so they can go into surgery and now where to make the cuts. Also, maxillofacial technicians can make templates and stents off that model to help the surgery," Sherry said.
Innovation at a snip
The cases Replica 3DM deals with are mostly very serious, but it is all in a day's work for the team, with projects varying from facial reconstructions after accidents to large-scale cranioplasties and even building interim prosthetics for those with congenital digital deformities.
But with 3D printing becoming increasingly mainstream, will NHS trusts not be investing in their own 3D printing laboratories? Sherry does not believe so.
"We have about 15 trusts come to us for models and we are set up as a 3D hub for the NHS, but this is growing. We can cover those trusts for a fraction of what it would cost them to set up their own 3D printing operation themselves, when most trusts only need about 10 models a year," Sherry said.
In addition to producing 3D-printed models for NHS trusts across the UK, Replica 3DM is involved in its own research work that could further develop how plastics are utilised in the medical field.
In collaboration with Southampton University, the company is developing a 3D printer that can print hydroxylapatite (ha), which replicates bone and has a programmable dissolution rate, and polyaryletheretherketone (PEEK), which is inert and can therefore be implanted in the human body.
"Because you can set the rate at which ha dissolves, you can print small scaffolds with it. The ha dissolves and what you have left is bone."
The government-funded project will take up to three years to complete, but Sherry has ambitions of this technology becoming part of the NHS.
"It will revolutionise things like cleft palate surgery, which requires grafts such as bovine grafts or in some instances I've heard they can use coral. With this, though, we could revolutionise how cleft palates are treated."
Sherry remarked: "Every week we produce something quite new and exciting, we do a lot of innovation work and we're always looking to 3D print items that are innovative.
"This is the first job I've had where you feel like you're doing something genuinely constructive and useful."