Products and Design

3D printing custom trachea stents

Shapeways offers the chance for designers of all kinds to turn their ideas into reality – be that in the world of tech accessories, fashion innovation, art and design, and in this case, the medical world.

A group of clinicians, architects and engineers teamed together to create 3D printed traechea stents unique to the patient. We spoke with Noah Garcia who is working with Harvard doctors and MIT material specialists to spearhead this new world for airway stents. Starting off with CT scans, the engineers initially started with Formlab printers, but the lack of biocompatible material lead them to Shapeways. While we do not offer 3D printed biocompatible material, our castable wax offering allows the team to create molds that can be used for casting the necessary biocompatible materials. It’s really amazing to see this process – from the files to prototypes to a final wax version, it’s truly amazing to see how innovative this team is. The team has even offered a bronze “pendant” for fun!

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How long have you (and/or members of your team) been in the medical field?
Most of our team has spent the majority of their academic and professional careers in the medical field, while other members of our team have had no medical experience at all. The process of creating custom stents required building a unique collaboration between clinicians, architects and engineers. Our clinical team knows a great deal about biology, physiology, and medical pathology, but little about 3D fabrication/computation, while our architects and engineers know a great deal about 3D fabrication, but little about biology. The crossbreeding of the medical and artistic professions is what has made this project possible. Our team includes George Cheng MD PhD, Erik Folch MD, Sebastian Ochoa MD, Mark Tibbitt PhD, Adam Wilson MS, Noah Garcia BArch, Robert Brik MS, Sidhu Gangadharan MD, and Adnan Majid MD. Dr. George Cheng is a clinician specializing in pulmonary medicine and has been leading this project.

How did you involve 3D printing in your practices? When did that begin?
Dr. Cheng first became interested in the possibilities of 3D printing after reading a 2013 article in the New England Journal of Medicine that detailed how researchers implanted a 3D printed tracheal splint into a pediatric patient with a collapsed airway. He believed that data from a CT scan of the chest could guide the production of airway stents or other airway prostheses. The research efforts were supported by Center for Integration of Medicine and Innovative Technology. The origin of the project was further documented in a Boston Globe article last year. Dr. Cheng recognized an opportunity to employ 3D printing technology as means to customize the trachea stents. Traditional stents are rudimentary extrusions, which do not fully represent the specific shape of a person’s airway. Airway obstruction from stenosis, malacia, or extrinsic compression can result in significant respiratory symptoms and decrease in patient’s quality of life. In recognizing that traditional stents may lead to significant complications, Dr.Cheng hypothesized ways to customize and optimize the forms. Traditional airway stents are made of silicone, metal, or hybrid materials, and are limited by their cost and complications. Common complications such as migration and granulation tissue formation may be related to inaccurate stent size and shape. Dr. Cheng and his team developed a workflow using CT scanners to extract 3D models of a patient’s trachea to guide the design of custom stent matched to the individual’s airway. The resulting 3D prints are anatomically accurate seamless surfaces, diagonal grids and circumscribed double ­helixes that follow the contours of a patient’s airway.

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From top left to bottom right, beginning with the CT scan model and ending with 3D prints. The CT scan is manipulated with Rhino and parametric modeling plug-ins. The inner surfaces of the trachea are isolated, a diagonal grid is mapped to the surface and the resulting diagrid is exported as a printable file.

Did you know how to 3D model prior to this project?
The engineers, architects and artists on our team are primarily experienced in digital computation for architectural and sculptural design. The clinicians, on the other hand, are experienced with producing 3D models from CT scanners. By bringing together these two worlds of art and science, we are able to achieve significant 3D modeling possibilities. There were scale and tolerance challenges to address when translating from digital models to 3D prints with certain materials, but we are continually making discoveries during the process. Our current challenge is to use the 3D printed forms to create molds and armatures that can support biocompatible materials. Shapeways’ castable wax material has us hopeful of achieving our goal. We’d hope to one day print in our biocompatible materials directly, but until then, we are limited by the available 3D printable materials. Our ideas are ahead of us in many ways, but we are excited to be learning and exploring the unknown.

Why tracheas? Will you experiment with more areas of the body?
The clinicians on our team specialize in pulmonary care and sub­specializes in the field of interventional pulmonology. One of the major disease entity they encounter is large central airway disease. Trachea stents can be deployed into and removed from an airway through minimal­ invasive procedures in a relatively short amount of time. As compared to a heart stent, which is much smaller and more dynamic, a tracheal stent has fewer variables with easier methods to control. Using the tracheal stent as a starting point, we are considering how our process might be applied to other areas of the body. For now, we are aiming to perfect the trachea stent and then explore how our methods can impact other parts of the body.

It’s fascinating to see and learn more about how 3D printing and the medical world are combining forces. Thank you for such a wonderful interview, Noah! Check out the pendant below, and let us know if you have a medical story to share with us in the comments below or by emailing community @ shapeways.com.

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