January 20, 2014

It’s no secret that 3D printing has a lot of potential in the medical field. In recent weeks we’ve reported on a number studies looking to develop bio-printed skin tissue, organs, you name it. For instance, just this week the Japanese government announced a whole round of investments aimed at developing 3D printable human organs.

But there are also other 3D printed medical applications that are easier to realize, don’t require bio printed tissue and can potentially save many lives as well. The young industrial design student Hamish McIntosh, studying at the Victoria University of Wellington, New Zealand, is pioneering one of those interesting applications. In a nutshell, he is developing 3D printed anatomical models that can be used to educate medical students and help surgeons prepare for risky operations.

And no, this isn’t about the skeleton awkwardly standing in the corner of your biology classroom in high school. Instead, he is creating accurate representation of body parts (like your trachea) that will allow doctors to study problems before actually cutting your windpipe open. Perhaps more impressive, he is 3D printing tissue that accurately mimics the flexibility and properties of human skin, and can be used by student to practise, for instance, stitching up wounds. Because no-one likes to be someone’s first ever patient.

As Hamish explained on his website, he has always been passionate about drawing things and working on new designs, so 3D printing was a natural avenue to pursue during his studies. He is especially interested in the way this technology can ‘affect our lives, or specifically what benefits the technology will have in the medical profession.’ Working on medical designs was thus a logical step to take.

His master’s programme has mostly been focusing on the Simulated Anatomy project, which, in his own words, revolves around multi-material 3D printing to simulate anatomy: ‘Multi material printing allows the use of rigid and flexible materials to simulate the different densities of the human body so that models components can be 3D printed to feel like human anatomy. 3D printing also allows individual customisation of models so that CT or MRI scan data can be used to create an anatomical print unique to a specific patient. Such prints should be beneficial to medical training and the understanding of anatomy.’

Practically speaking, he has been developing a very promising anatomical model of the human neck, a very diverse section of the body filled with differently behaving organs like the muscles, windpipe, larynx and, of course, skin. While this might seem like a small area to focus on, the sheer cost of the technology and complexity of the region means it’s more than enough as it is. His hard work has resulted in a very beautiful multi-component model that has been developed with help from clinicians throughout the process.

Now, as this is such a diverse area with varying thicknesses, densities and flexibilities, Hamish was forced to rely on both a regular FDM 3D printer and even a Stratasys’ Connex 3D printer to realize all the different components. But even with the help of Stratasys technology, it was an arduous design process requiring lots of iterations and advice from medical professionals. ‘Being surgeons they had much more of an eye for the internal detail and pointed out the flaws in the [earlier models] including the cricoid cartilage not being prominent enough, the muscle being too hard, and the lack of articulation between the cartilages.’


After various iterations, however, Hamish was able to produce a very impressive model that accurately mimics the structure of the human neck. During his fifth visit to the Wellington Hospital, ‘there was a lot more enthusiasm about the feel of the skin and trachea components which was great to see.’

But perhaps most impressive is the 3D printed skin component of his Simulated Anatomy project. ‘The clinicians involved in this research identified early on a desire for 3D printed models that behave like human skin for practicing basic skills such as suturing [stitching]. One of the main challenges faced in using multi-material printing was overcoming some of the material properties, including the material being too slippery to grip, and not having the compliance (or movement in other words) of human skin.’

Now, as you can imagine 3D printing skin is an arduous process, especially as it requires a very high level of flexibility. To achieve that, Hamish resorted to ‘creating an excess of material at the borders of the print that would allow for the correct amount of movement, and by applying a texture to the surface of the model.’ And as you can see in the footage below, the result is a very impressive human-like skin texture.

In the long-term, he hopes to create a ‘working prototype of the human body, and sections of that which can be used to test medical tools and specific procedures. These could, he briefly speculated, even feature colors or contain fluids for a more realistic experience. However, as Hamish’s studies and research are still on-going, it will probably be a long time before medical students start to practise their skills on 3D printed dummies rather than people.

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