Algorithms and 3D Printing Can Be Used to Create Realistic Nasal Prostheses

May 17, 2018 by Sarah Saunders 3D Printing Medical 3D Printing Science & Technology

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[Image: Fripp Design]

While it’s a shock to lose any body part, psychological impact runs especially deep when a part of the face, like the nose, is impacted, as it’s so visible and so ingrained as a part of personal identity. In 2015, researchers at Morriston Hospital in Wales were hard at work developing a way to grow new tissues from human cells. They would later be combined with a liquid formula to create a jelly-like structure used to 3D print missing body parts before being strengthened with reagents, placed into an incubator, and fed nutrients in order to form cartilage.

At the time, the researchers believed that we were only three years away from being able to 3D print full ear and nose transplants. While we’re not there quite yet, 3D printing has enabled the creation of more lifelike facial prosthetics.

A collaborative study out of the University of Maryland (UMD), the Penn State Hershey Medical Center, and the Veterans Affairs Maryland Health Care System, titled “Assessment of a Novel Computer Algorithm for Printing a 3-Dimensional Nasal Prosthetic,” was recently published in the monthly JAMA Otolaryngology – Head & Neck Surgery peer-reviewed medical journal.

A computer algorithm that the team developed can be used to create a 3D nose model. The main question the paper is trying to answer is if the researchers’ novel 3D printing technique can be used to create nasal prostheses that are similar in appearance to the patient’s real nose, which could mean that patients don’t need to spend the time and money visiting an anaplastologist – a professional who creates custom maxillofacial prosthetic solutions.

According to the paper, “In this study, we describe an algorithm to model the patient’s nose using 2-D images to model and print a 3-D model using a desktop 3-D printer. We propose a user-friendly and inexpensive technique to model external anatomical features of a nose using 2 commercially available software packages. Our hypothesis is that the algorithm can produce a 3-D model of a nose that is similar to the patient’s actual anatomy. To test this hypothesis, we used the algorithm to create 5 individual noses based on 2-D photographs. We then surveyed practicing physicians, residents, and medical students regarding the similarity of the 3-D printed nasal prostheses to the 2-D photographs. The objective of this study was to determine the feasibility of creating nasal prostheses by this method and to evaluate the similarity of these prostheses to patient images. Furthermore, we examined whether this computer technique could be used by individuals who do not have an extensive background in graphic design.”

From August to October of 2016, a prospective pilot study with a cross-sectional survey was conducted. 3D printed nasal prosthetics were created for five volunteers, and 36 survey respondents with medical backgrounds evaluated the nasal prostheses.

The research team’s computer algorithm used Blender and Adobe Photoshop CS6 3D animation software, and high-resolution 2D photographs of the volunteers’ noses, to create realistic nose prosthetics, which were then 3D printed on a LulzBot TAZ 5 3D printer using high-impact polystyrene material from MatterHackers.

The survey respondents, made up of medical students, residents, and attending physicians, were asked in a survey to rate the similarity between the volunteers’ photographs and their 3D printed noses on a Likert-type scale (0 to 10, where 0 is completely different from the photograph and 10 is identical to it).

“Thirty-six survey respondents evaluated 4 views for each of the 5 modeled noses (from 4 women and 1 man; mean [SD] age, 26.6 [5.7] years). The mean (SD) score for the overall similarity between the photographs and the 3-D models was 8.42 (1.34). The mean scores for each nasal comparison ranged from 7.97 to 8.62,” the paper reads. “According to the survey, respondents were able to match the correct 3-D nose to the corresponding volunteers’ photographs in 171 of 175 photographs (97.7%). All surveyed clinicians indicated that they would consider using this tool to create a temporary prosthesis instead of referring to a prosthodontist.”

The results of the paper indicate that the 3D printed nasal prostheses did appear to “closely resemble actual nasal photographs,” which means that they could be used in the future to develop temporary prostheses “to fill external nasal defects.”

Authors of the paper include Meryam Shikara, BA; Christopher J. Rizzi, MD; Brian Zelip, MS; Fleesie Hubbard, RN; Kavita T. Vakharia, MD; Amal Isaiah, MD, PhD; Jewel D. Greywoode, MD; and Kalpesh T. Vakharia, MD.

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