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Biomedical engineers at UNSW Sydney have their sights on developing anatomically accurate 3D printed models which mimic exactly the way body parts feel and move.

The ambitious plans come after researchers at the Tyree Foundation Institute of Health Engineering (IHealthE) recently designed and created a patient-based anatomical 3D model of a young child鈥檚 skull which helped surgeons devise and plan an innovative way of successfully removing a life-threatening tumour.

The team also created an exact replica of a specific patient鈥檚 trachea (windpipe) to help clinicians determine whether a certain surgical procedure could be performed safely.

Now the team are considering ways to make future 3D prints even more useful for medical professionals, by developing the use of different printing materials that recreate the complex way body parts feel and move.

3D printing anatomically accurate body parts

鈥淲hat we have been doing is making patient-specific 3D printed models so that clinicians can practise specific surgery techniques unique to their patient,鈥� said Dr Keng-Yin Lai, a postdoctoral research fellow at UNSW who helped create the models.

鈥淭hey are geometrically and anatomically accurate which is really useful. But I think the future in this space is using even more realistic materials during the 3D printing process and therefore understanding how parts of the body are actually going to bend and flex during surgeries.鈥�

The first bespoke 3D printing project came about when Catherine Banks and Jacob Fairhall from Sydney Children鈥檚 黑料吃瓜群网, part of the Randwick 黑料吃瓜群网s Campus, approached the team at IHealthE to produce an exact replica of eight-year-old Issac Lee鈥檚 skull.

Issac had been diagnosed with a craniopharyngioma, a rare and complex tumour at the base of his brain, and had already undergone two major craniotomy surgeries that required part of his skull being temporarily removed.

Banks and her team proposed a third, but this time less invasive, procedure via Issac鈥檚 nose and requested a 3D printed model of his brain and the tumour be created from imaging scans.

The model needed to show the precise size, shape and location of the tumour, but also other critical structures, such as the optic nerves, which had to be taken into consideration to ensure they were not damaged during the operation.

Pushing the envelope

Within 48 hours the IHealthE team were able confirm such a model could be designed and produced, which not only assisted in the surgical planning, but also helped Issac鈥檚 family understand the complexity of the procedure.

鈥淚 think we have a role as health professionals to constantly try to push the envelope of what we can offer our patients,鈥� said Banks, a specialist ear, nose and throat surgeon.

鈥淭he merging of people in the health profession with biomedical engineers and technical experts, such as those at IHealthE, is absolutely vital as we move forward over the next decade.

鈥淭hese 3D printed anatomical models allow us as surgeons to think about different trajectories for procedures. The models allow us to really plan our angles of attack, and consider all the instrumentation that we will need, so they are invaluable for providing us with more information than we鈥檇 get just from MRI or CT scans.鈥�

Lai subsequently helped design and produce a series of 3D printed tracheas for anaesthetist Phil Black, who wanted to determine whether he would be able to safely use a certain type of breathing tube on a young patient during complex spinal surgery planned for early 2025.

Black was presented with four different designs, which allowed him to be confident that an appropriate tube could be passed through the patient鈥檚 trachea, even though it was being significantly restricted due to the abnormal curvature of his spine.

鈥淭he primary issue with this patient, a young boy, is scoliosis, which is a quite severe curvature of the spine that is affecting his airway and breathing.

鈥淭he operation to fix that is long and difficult, maybe 12 to 16 hours. And he needs what is called an endotracheal tube placed in his airway 鈥� so I wanted to know what type and size would fit and where the problem points may be.

鈥淚 asked the IHealthE team if they would be able to 3D print this patient鈥檚 trachea, because there is nothing like having an accurate model in your hand and actually trying to pass a tube down it to give you reassurance ahead of the procedure.

鈥淲e can try to do calculations from a CT scan, but it is quite arduous. In this case it was great to have something simple and straightforward to show my colleagues and utilise their expertise in a very quick way.

鈥淧eople were able to propose ideas and we could easily test the suggestions, which really streamlined the decision-making process.

鈥淚 think 3D printing for specific patients is definitely going to become more widespread in the future, especially as it gets even faster. In the future it may get to the point where a patient comes in, and within an hour or two the CT scan and subsequent 3D model might be available to help predict and plan the best medical procedure.鈥�

Educating patients

Banks says the 3D printed models are also an important tool to educate patients and their families about the procedure that is being planned, to help them evaluate, give consent and also understand what will be happening.

鈥淓ven medical professionals can have some difficulty looking at two-dimensional CT or MRI scans and understanding the three-dimensional relationship between critical structures,鈥� she explained.

鈥淪o you can imagine how hard it is for someone with no medical knowledge to be shown scans and try to figure out how it all comes together.

鈥淭he 3D models are fantastic in demonstrating the spatial relationships between all the vital structures and we can show patients and their family what we are trying to achieve and help them to better understand the procedure and consider the risks before they give consent.鈥�

Despite their limitations as two-dimensional representations, the scans are fundamental to the process of creating the 3D models.

Experts such as Lai are able to use powerful computer programs to convert each of the segments of the scans into a design of an exact 3D replica of the patient鈥檚 body.

Sections of the model can be printed in different colours and at different opacity levels to better highlight certain structures, aiding both the surgeons and the patient in terms of better understanding the procedure.

Depending on the complexity of the specific request, it takes Lai around 8鈥�10 days to create the three-dimensional model in the program 鈥� in consultation with the clinician to ensure it is accurately representing all the key structures in the best and clearest way.

Once everything is approved, the design is sent to the 3D printer which creates the model in approximately 20鈥�30 hours 鈥� again, this varies from model to model.

The 3D models created so far have been produced using a photosensitive resin which is hardened, or cured, via exposure to ultraviolet light.

Bio-mimicking materials

IHealthE researchers are now exploring the possibility of printing with so-called bio-mimicking materials.

鈥淎t the moment with these 3D models they are anatomically accurate and that allows the clinicians and the patients to better visually understand the dynamics of certain structures,鈥� said Gabriel Graterol Nisi, Senior Technical Engineer at IHealthE.

鈥淏ut in the future I can imagine using a mixture of printing materials that can also mimic the precise texture and hardness and flexibility of the tissues or bone structures.

鈥淭he bio-mimicking materials can be created, for example, by depositing the resin in complex patterns that recreate porous bone structures, fibrotic tissues and ligaments.

鈥淯sing that would allow us the ability to replicate musculoskeletal models that match bone density characteristics and behave like native bone when force is applied such as discectomy, drilling, reaming or sawing.

鈥淲ith 3D models using those materials the surgeons would not only be able to plan, but also accurately practise the procedure and really understand the way everything will feel and react.

鈥淭hat is the next step in future developments and I think it will only enhance even further the possibilities of surgical planning.鈥�

Black agreed that developments in bio-mimicking materials would be hugely beneficial to medical professionals.

鈥淔or a certain select group of patients it could be essential to have 3D models made of materials that accurately mimic the real body part.

鈥淒ifferent patients have bodies with different degrees of flexibility and pliability and tightness. So being able to know exactly how much a piece of tissue will be able to move, or compress, or distend would certainly be beneficial.

鈥淚t would definitely be a big advantage compared to just looking at scans on a screen 鈥� to be able to physically test how much the tissue moves and in which direction it might move.鈥�

Integrated acute services

The bespoke patient-specific 3D printing service, believed to be unique in Australia, has grown out of the recent relocation of IHealthE to the new UNSW Integrated Acute Services Building (IASB) attached to the Randwick 黑料吃瓜群网s Campus as part of the multimillion-dollar Randwick Health & Innovation Precinct project.

Within the new building, UNSW is housing state-of-the-art research, clinical innovation, biomedical and teaching facilities across 10 floors.

The spaces are designed to facilitate partnerships in tech solutions for diagnosis, treatment and prevention of a wide range of conditions, with researchers and clinicians sharing ideas, prototypes and data analyses.

As shown with the success of the patient-based anatomical 3D printed models, such collaborations are already helping to uncover unmet clinical needs and design innovative solutions to improve patient outcomes.

Sandy Wigley, Strategy and Innovation Project Officer at IHealthE, said the 3D printing highlights the strengths of the Institute and showcases the benefits of being based in the IASB in close proximity to clinicians and medical experts.

鈥淭he main aim of IHealthE is to pair unmet clinical needs with novel medical technology solutions,鈥� she said.

鈥淚t isn鈥檛 about us just creating something cool and then trying to find a problem that it can be used for. We are here to hear what problems need to be solved and then creating a technology that can fix it.

鈥淥ur innovation team have a wealth of engineering experience and experience with medical technology startups. We have professors of practice with decades of experience working with med-tech, as well as specialist engineers who are able to do rapid prototyping when fast solutions are required.鈥�

Image caption: Patient-specific 3D printed models have been produced using a photosensitive resin which is then cured under UV light. Image from UNSW/Jake Willis.