Another dimension: The art and science of 3D printing body parts

Current

 

By Michelle Pucci 

“In 1875 I returned from abroad while having been appointed demonstrator of anatomy whilst in Vienna,” writes Francis J. Shepherd, MDCM 1873. “I also stirred things up.”

Shepherd revolutionized the teaching of anatomy at McGill by moving the focus from the lecture hall to the dissection room.

Today, the tradition of “stirring things up” and “learning by doing” continues at the Faculty via a new generation of trailblazers who have embraced the possibilities presented by technologies such as 3D printing.

Dr. Geoffroy Noël is a prime example. Like his predecessor, Shepherd, Noël picked up his anatomical skills in Europe, in his case, at Normale Supérieure in his native France. His initial experience, dissecting a brain with a fellow medical student, sparked an interest in neuroanatomy, a topic he went on to teach as a graduate student at the University of British Columbia.

Since settling in Montreal in 2014 to become director of the Faculty’s new Division of Anatomical Sciences, he’s made it his mission to bring more students into the anatomy laboratory. “When I took on the Division, only Medicine and Dentistry were involved in the lab on a regular basis,” he says. He has since opened up the facilities to students from the School of Physical & Occupational Therapy (SPOT) and the Ingram School of Nursing (ISoN). Under this silo-breaking approach, SPOT students teach medical students who, in turn, reinforce what they have learned by teaching it to their peers in Nursing.

“Health care professions that have a patient in hand should really know the anatomy in order to safely treat a patient,” he says. “The downfall of this is that not all the students have enough time to do all of it. That’s why you need to have complementary tools.”

By complementary tools, Noël means 3D-printed models or haptic simulations, virtual models that can be modified, stretched and rotated on a computer, and are responsive to such cues as a hard or soft click of a mouse.

Noël’s first forays into 3D printing included brain stems and ventricles. He also created sinus models for the Department of Otolaryngology to use to teach bone drilling, and heart models on which students could practice their ultrasound skills.

His current goal is to have 3D-printed models available for every student to take home. His division is in the process of acquiring a new printer, the Ultimaker 3, which will add to the growing number of printers already available across campus. It is his hope that students will be able to make low-cost models to rent or sell to one another.

At the same time, Noël is overseeing renovations of the anatomy laboratories in the Strathcona Anatomy Building, a project that will update equipment, open up work spaces and re-invite natural light through the mullioned windows. His efforts have earned the notice of students. The Medicine Class of 2015 awarded him the Osler Outstanding Teacher Award, intended for the teacher with the greatest influence on their future careers.

HAVE BRAIN, COULD TRAVEL, BUT…

A ten-minute walk away from the Strathcona lies the Steinberg Centre for Simulation and Interactive Learning (SCSIL). It was at the Centre, which occupies 31,000 sq.ft. of space on the lower level of the Galéries du Parc mall, that Dr. Ricardo Faingold, Assistant Professor of Diagnostic Radiology and Program Director of Pediatric Radiology at the Montreal Children’s Hospital of the MUHC, first unveiled his creation, a relatively easy-to-make, low-cost baby brain phantom.

A phantom is similar to a 3D-printed model, only made of a softer, transparent gel-like material. In pediatric and radiology training settings, baby brain phantoms are an inexpensive tool used to teach head ultrasound techniques. Head ultrasounds are only possible for infants up to twelve months old. As long as the soft spot, or fontanelle, has not yet closed, ultrasound waves can still pass through.

According to Faingold’s research, when residents practise performing ultrasound scans on brain phantoms, the quality of the images on their actual scans then improves.

To create one of his brain phantoms, Faingold begins with the MRI of an infant segmented and sliced into images. Based on that, he 3D prints brightly coloured plastic brain models. These models are used to create a silicone mold that is flexible and filled with a polyvinyl alcohol cryogel solution. When the mold is removed, the result is a spongy phantom brain. Kept in a cylindrical plastic container filled with water, the phantom is portable and keeps well in the fridge. The brain is so detailed that ultrasound images capture features of the brain’s cerebral hemispheres and ventricular system.

Faingold has donated a few of the phantoms that he has created to colleagues in Toronto, Boston and Florida. His main focus now is on using the model for teaching at McGill.

When asked whether he can envision an application for his phantoms in the developing world, Faingold explains that although there is a need for this kind of affordable, accessible tool, there are also many barriers.

As an example, he cites his own experiences at Maputo Central Hospital in Mozambique, teaching staff and residents to perform ultrasounds and other radiology exams. There, he found donated ultrasound equipment left in unopened boxes for lack of assembly know-how—all the more disappointing because ultrasounds are inexpensive, making them more useful for diagnostics in places with fewer resources. Faingold taught staff in the hospital’s Neonatal Intensive Care Unit to use ultrasounds to identify life-threatening conditions. “With the premature babies, we have to do these ultrasounds next to them at their bedside,” Faingold says. “It’s very important to train residents well before they go and perform these exams on sick newborn babies.”

Although the brain phantom could contribute to training in places like Mozambique, and is easy to make and store, Faingold now hesitates to travel abroad with it. “It’s okay when you are transporting the phantom by car or by plane domestically,” he says. “But when you start crossing borders, it gets more complicated.” The materials—what looks like a refrigerated baby brain floating in water—can arouse suspicion. So, Faingold is developing a digital “phantom brain,” which can be used to teach, without causing a stir about potential biohazards at customs, or raising questions about why a foreigner might have a brain in his luggage.

“My goal is to, maybe within six months or a year, create a new sort of technology, what I’m calling the virtual brain experience,” Faingold says, adding that software is sometimes an easier sell than a physical model when it comes to this kind of training. “It’s easier to be accepted as opposed to a product that you buy and sometimes have to maintain.”

THE SIZE AND FEEL OF AN ARTERY

Increasingly, major steps forward in medicine require collaboration with other disciplines. In 2016, a multidisciplinary team of McGill researchers led by Dr. Jake Barralet, now Director of Innovation, SCSIL, received $1.6 million from the Natural Sciences and Engineering Research Council of Canada to develop surgical devices and foster “innovation-oriented” graduate students. The program, Collaborative Research and Training Experience (CREATE), brings together students of surgery, business and engineering to develop technology for health care and industry.

Justine Garcia, a PhD candidate in the Department of Mechanical Engineering, is one of those graduate students. Using an Objet500 Connex3 (Stratasys) printer, Garcia and collaborators seek to 3D print aortic tissue with patient specific properties.

“At first we chose to use 3D printing because you can create any shape you want. That is quite important because the model that we want to create needs to have the right geometry of our patients,” Garcia says. Surgeons can train for surgery using models created with patient organ dimensions, or using models that mimic bulges caused by aneurysms and calcium deposits along the aortic wall.

“Compared to other methods, it’s very easy to do, but when we use 3D printing we are very limited in terms of material,” Garcia says.

No single material available for 3D printing can mimic the tissue of an aorta. Models of the vascular system available for training purposes are unrealistic. They are often made from hard plastics, are oversized, and don’t represent different properties of diseased tissue. Cadavers donated for medical training are expensive to maintain and limited in availability.

In order to print an object that resembles the size and feel of an artery, Garcia developed a new material with her supervisors, Associate Professor of Surgery Kevin Lachapelle, MDCM’88, PGME’95, Associate Professor Rosaire Mongrain in the Department of Mechanical Engineering and Professor Richard Leask in the Department of Chemical Engineering. The new material is composed of the following three parts: rigid fibres, a flexible structure and brittle support.

“It’s a tool to reduce the use of cadavers,” Garcia says. “But also it’s a tool that gives students a chance to train well before going into a real surgery.”

“You could take a patient’s specific anatomy and pathology, print it out, and actually do the procedure beforehand,” says Lachapelle, Interim Director of the SCSIL, where he was also the founding director. “For trainees, you could create hundreds of these kinds of encounters. From a surgical perspective, that normally would take years for you to encounter if you are just waiting for those kinds of things to happen on your clinical rotations.”

Garcia’s PhD involves mechanical testing on aortic tissue and the composite material for 3D printing, and the similarities are promising. Surgeons are now testing the models and offering feedback. Next, researchers will work towards introducing a blood flow to the models, to better simulate the cardiovascular system. Eventually, residents could practice their cutting and suturing on aortic tissue connected to a heart that is pumping blood and enveloped by a ribcage and model chest.

COMPLEMENTARY APPROACHES

McGillians have used 3D printers to build an ice sculpture of our University’s founder, as well as parts for the Mars Rover. “Printing is nothing,” Noël says. “It can take between two to six hours.” It is the prep work beforehand that is more demanding. Working with Robert Funnell, BEng’69, MEng’72, PhD’75, Associate Professor, Department of Biomedical Engineering and Otolaryngology, Noël has created a collection of medical images for 3D printing.

Selecting the right printer for the project is important, he says. Different printers use different types of materials and can achieve different levels of detail. And when it comes to producing body parts with realistic properties, there are fewer materials from which to choose. Noël uses thermoplastic urethane, for flexibility, or polylactic acid, for the cheapest option.

Can 3D printing and virtual simulations replace the experience of being in an anatomy lab? Not according to Noël, for whom dissection remains an essential. In the lab, he points out, students are learning many other valuable skills such as professionalism, ability to work in teams, and a respectful approach to death: “There is a lot of psychosocial development that is happening with cadaveric material that would not be the case with 3D-printed material.”

On a technical level, 3D printers can’t replace planes of fascia, the connective tissue that is integral to the relationships between structure.

And no model can replicate the way pathologies, variances and donor history impact the anatomy, Noël says.

STIRRING THINGS UP, MIXING WORLDS

Simulation technology like Garcia’s 3D-printed aorta is intended to prepare surgeons before they set foot in an operating room, but the research has its roots in real-life situations. For Garcia, embarking on this project meant embracing a world of medical technology, and also entering an operating room for the first time.

She remembers the sounds of cutting bone, but also the cooperation between surgeons and technologists. “It’s beautiful like choreography. When you see all those people, they know what to do, and they do it together.”

Be Sociable, Share!

Comments are closed.