Article in brief
Hilary Mullane, a second-year neurologist at NYU Langone Medical Center, shares her experience building anatomical models using 3D printers and the benefits of technology in the medical field.
Hilary Mullane, MD, spent more time than most children with neurologists during her childhood. “I had absence seizures as a kid, so I became familiar with doctors,” recalls the sophomore neurologist resident at NYU Langone Medical Center in New York City.
“Overall, going to the neurologist was a very positive experience for me. I was very interested in looking at the EEG. At the time, it was done on this long roll of paper, so we would take it home and flip it over and try to figure out where the seizure was. Of course, As a 6 or 7 year old, you had no idea. But I was curious, and that curiosity was something I never really got away with, and it drew me to this point.”
As is often the case, absence seizures gradually disappeared as they grew, but Dr. Mulan’s fascination with the brain remained. It also fostered her continued love of art, even though she had no formal training in the field.
“My art was purely based on a hobby – for example, I really enjoyed making paper art, taking an X-Acto knife and cutting out different shapes,” she said. “During medical school, I made anatomical hearts that I was able to publish in the Journal of Medical Humanities online, and I did a few neurons as well. But it was mostly just a stress-relieving hobby.”
Then, in her freshman year at the University of Massachusetts Medical School, she was introduced to 3D printing. “Our anatomy lab had access to a 3D printer, and one of the directors of the anatomy lab, Jasmine Carter, a Ph.D., was interested in doing a project to create a model of the female pelvis,” said Dr. Mulan. “It’s a very complex area of anatomy, and structures are not well visualized by anatomy, so the idea was to create an educational model to illustrate the spatial relationships between structures.”
Despite having no background in graphic design or engineering, Dr. Mullane was intrigued and eagerly volunteered to take on the project. With Dr. Carter, assistant professor of translational anatomy and founder of the 3D Anatomy Innovations Lab, she spent the summer between her first and second years of medical school building the model.
“Doing technical and engineering design like this was very new to me. But I was very curious and heard a lot about 3D printing, and it seemed like a unique skill set,” she said. “I did some reading about its uses, and it seemed like a valuable technology to invest my time in — both in its applications and the nitty-gritty of how it could actually be used to create structures and applications for drug development, prosthetics, and so on.”
The project included a comprehensive review of 2D anatomical atlases, as well as examination of cadaver materials and magnetic resonance imaging of muscles. “I used a graphic skeletal program to draw the different components of the pelvic anatomy and put them together. It was a very difficult process,” she said. “I ended up importing some 2D images into mechanical engineering software and drawing the structures based on that. The program is set up so that you can start with a ball or other 3D shape and then use the tools in the program to sculpt the shape, making it more flat like a muscle, for example. I found my pelvic bones online that someone else created and imported them into the software.”
Perhaps the most difficult aspect of the task was that the software I used (Fusion 360 and MakerBot) is primarily designed for inorganic shapes like squares, boxes, or plates you might put a screw in.
“When you think about the human anatomy, there are a lot of complicated curves and angles that aren’t simple geometry,” she said. “It’s a very laborious process of adapting the software to calculate that. Each shape is made up of a bunch of lines and joints. What you do in the end with the software is, to get the shape you want, you select different vertices and then drag them out or push them in. It’s kind of sculpting with clay, just on a computer screen. This was a few years ago, so there are much more efficient ways to do this now. For example, there is now software available that allows you to identify blood vessels more easily than having to draw them yourself. You can specify a certain intensity of color, so using images of Computerized tomography with contrast can illuminate vessels.”
Besides software and design challenges, the 3D printer hardware itself taught Dr. Mullane an entirely new set of skills. “It can be very challenging. There is a lot that can go wrong,” she said. “You have to learn how to adjust the temperature settings and how to troubleshoot when it doesn’t work. The printer I’ve been using is similar to an inkjet, but instead of the ink coming out of the nozzle, it’s plastic, and the nozzle moves around the build plate, and the plastic is stacked on top of it. The model is built inside a plastic scaffold, so if you have very narrow sections, the structure is supported by that extra scaffold while the printer prints it. You must select the correct settings for the scaffold, so that it supports your structure during printing, but at the same time the scaffold cannot leave material remaining on the model when you take it off. And of course, for plastics, the whole point is for it to harden, so sometimes the nozzle gets clogged.”
But a summer spent fiddling with microplastics, clogged nozzles, and design tweaks paid off: The project was a huge success and Dr. Mullane won the 2019 Technology Award from the Massachusetts Medical Association. She has since shared the model with a physical therapy program, which he plans to use in teaching pelvic anatomy. It was also used to supplement autopsy in a first-year school autopsy course, and shared models with the departments of obstetrics, gynecology, gynecology, and urology at the Medical School, for experimental use in anatomy education lectures. “This has really given me a lot of satisfaction and is a project I’m very proud of,” said Dr. Mulan.
Despite her early interest in neuroscience as a child, earning an undergraduate degree in neuroscience and biology, Dr. Mullane briefly toyed with the idea of pursuing other medical specialties. “Eventually, I ended up going back to neuroscience. I love how important the physical exam is. I love the importance of history and talking to patients.” computerized.”
During her stay, her opportunities to pursue 3D printing and model design were more limited, but she is excited about her possibilities in medical education. “It is particularly relevant to neuroscience because a lot of how we understand diseases or treatments depends on our understanding of this very complex anatomy,” she said. “One of the great things about 3D printing is that a number of models are freely available on the internet and anyone can download and print them, so I’ve been working on building a small library of these models. There’s a brain stem that I found and printed, and a number of skull and inner ear models, which I found and printed out. Also. I think understanding the anatomy of the nervous system is very important in neuroscience and that having 3D models can really help as much as visualizing the spatial relationships between different structures: the blood vessels, the brain, the bones of the spinal cord.”
But the models I’ve seen online are relatively simple for the most part, and Dr. Mullane has a bigger insight. “There are many different structures inside the brain, and the models available usually only show you the surface of the brain. What I would like to develop is a model that you can “unpack” and compare to a CT scan or an MRI, to better understand where things are.” “A lot of our understanding of stroke, for example, revolves around understanding the relationships between blood vessels and the parts of the brain that the different vessels provide. I would like to make a complete model of what the normal blood vessels of the brain look like.”
Ultimately, you envision creating a comprehensive library of neuroscience models for medical education. “Commercially available models can be expensive,” she said. “I am very fortunate that NYU has access to a 3D printer that we can all use for free; the cost-effectiveness of these models and your ability to share them worldwide with anyone is a unique advantage compared to simply purchasing a skull model on Amazon. All of these models are Basically computer files, so if we build a model here in New York, someone on the other side of the world can learn from it. This is especially important when it comes to treating rare anatomical abnormalities or rare diseases.”
To build her skill set, she also prints models designed by others, such as NIH libraries. “It’s not like you always have to reinvent the wheel,” said Dr. Mullan. “I’ve mostly been adapting these templates to develop a library for residents and medical students here. They think it’s cool, but I haven’t quite turned them away from PowerPoint slides yet. It’s much cooler, though! It’s something you can carry around, transform, and examine on all sides.”
Dr. Mulan is excited about the many potential applications of 3D printing in medicine. “There are prosthetics, and surgery, and now some pharmaceutical companies are working on 3D-printed tablets in order to modify the kinetics of drugs,” she said. “These pills are more porous than regularly made pills and dissolve instantly in your mouth with water, which is good for people who have a hard time swallowing pills.”
In fact, the first drug approved by the Food and Drug Administration with a 3D printer was the epilepsy drug – levetiracetam (Spritam).
As a sophomore neurology resident, Dr. Mullane will soon choose a subspecialty and possibly a fellowship, but she admitted she’s still hesitant. However, there is one factor she is sure of: “It is important for me to pursue a career that includes both clinical and non-clinical aspects, such as partnering with others on these 3D models and participating in medical education,” she said. “Working on these models piqued my interest in teaching, due to the amount of my knowledge that was enhanced through work. It really helped me with the process of imagining. Also, medicine can be a very stressful profession in many ways, and the arts and creative expression have been an outlet for a lot of my stress.”