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Four �������� students from the Thomas J. Watson College of Engineering and Applied Science are exploring the use of 3D printing technology to create orthoses for those recovering from injuries of the proximal interphalangeal joint (PIPj). This is the “hinge” joint in the fingers and it’s one of the most common hand injuries, especially among athletes.

For their senior project, systems science and industrial engineering (SSIE) student Nasiah Brown and biomedical engineering (BME) students Melanie Lyons, Angelina Mitchell and Ben Wolin were tasked with creating a 3D-printed, customizable orthosis to fit the fourth digit of the hand (ring finger).

Capstone projects have been part of the Watson College curriculum for years, but until now, students have never had access to a certified occupational therapist and hand specialist right on campus.

Enter Jane Bear-Lehman, professor and founding director of the new Division of Occupational Therapy at Decker College of Nursing and Health Sciences, who is serving as a faculty advisor for the project along with Jia Deng, assistant professor in the Systems Science and Industrial Engineering Department at Watson College.

The ability to work across disciplines, especially engineering, was a key factor in Bear-Lehman choosing ��������, which she joined in January 2020.

“I’ve worked extensively with engineers since my PhD studies to answer the many questions from my clinical practice in hand therapy that could only be answered with engineering,” she said. “The chance to collaborate on research was part of my reason for being excited about joining ��������.”

The ability to work with students from outside his major is the reason Brown selected this project topic.

“Doing a project outside SSIE has given me a chance to see something new and gain experience working with other engineers,” he said.

To help students understand a PIPj injury and current treatment methods, Bear-Lehman worked with Decker’s Innovative Simulation and Practice Center (ISPC) to set up a special, in-person demonstration for the team last fall.

When a person with an injured PIPj visits an occupational therapist (OT) for the first time, the OT will typically create a customized orthosis for the individual during that 45-minute appointment. This orthosis is meant to immobilize the injured PIPj while still allowing the soft tissue to glide. It must also protect both the injured PIPj and the volar plate — the ligament that connects the bones in the finger. Further, the orthosis must have a mechanism that enables it to be slipped on and off for therapy, to avoid future stiffness and to accommodate changes due to inflammation.

To meet these biomechanical requirements, OTs manually design and fit the orthosis using a thermoplastic material and hook-and-loop strapping for closure. However, reheating the thermoplastic material to make final adjustments sometimes can cause mechanical failure and low-quality fitting.

Brown, Lyons, Mitchell and Wolin have been working over the fall 2020 and spring 2021 semesters in Watson College’s Fabrication Laboratory (Fab Lab) to develop designs, evaluate materials and equipment, create prototypes and test the models.

“3D printing has the capability to fabricate customized shapes very fast,” said Deng, whose expertise in advanced manufacturing make him an ideal co-advisor for this capstone project.

“I bring knowledge of 3D printing in terms of selecting materials, helping the students understand the technology and providing suggestions about what kind of printers to use for different applications.”

This is Deng’s first time serving as a faculty advisor for a capstone project and his first time working with an occupational therapist.

“It has been a unique experience, marrying 3D printing and occupational therapy, but I love it,” Deng said. “I didn’t know too much about OT at the beginning, but I’m learning!”

The students created a COVID bubble since they typically worked together in person and met with their advisors via Zoom every two weeks. By the end of the fall semester, the students had created a plan and began working on the design concepts.

“Ideally, the process of obtaining measurements, inputting data into CAD, 3D printing and giving it back to the patient should take about 45 minutes,” Mitchell explained. “This will provide the patient with an orthotic specifically made for them within the initial appointment. Comfortability and user-friendliness were all taken into consideration when creating our design.”

By March 2021 the students had created several designs and prototypes, which they exhibited during a mid-year capstone project presentation. After gathering feedback, they moved on to testing.

To test the 3D-printed prototypes, the students returned to the ISPC so they could use the center’s high-fidelity patient simulators (manikins) under the guidance of Patti Reuther, ISPC director. The students were able to place the orthosis on the manikins and measure digit circumference and distance between finger joints, then the manikin’s fingers could be programmed to swell, providing the students with additional data.

“The students would go back and forth between the ISPC and the Fab Lab, printing out devices and then fitting them on the manikins,” Bear-Lehman said. “I don’t know how many trips they made back and forth, but it was a lot, because they’re meticulous!”

The lengthy test phase included mechanical testing, durability testing, comfort testing, disinfection testing, time-of-system tests and human survey tests.

After some tweaks based on feedback, the team had its final design.

Brown, Lyons, Mitchell and Wolin created an open-framed, cylindrical orthosis intended to be 3D-printed for a customizable fit. The brace has a frame structure that allows protection and breathability, while an insertable slip provides compression to reduce inflammation, increase comfort and promote cleanliness. The slip is composed of a composite material of nylon, spandex and gelatin silk. There is a slide mechanism along the top and bottom rails that has a locking rabbet joint that enables the patient to easily slide the halves together when putting the brace on or taking it off.

The device inhibits the PIPj from moving while leaving the distal interphalangeal joints (DIPj) at the tip of the finger and metacarpophalangeal or knuckle joints (MCP) free to bend. The length and diameter of the orthosis is determined based on the patient’s digit circumference and the distance between the MCP and DIP joints is determined from manual measurements. The OT would input these measurements into a parametric model using CAD software and then fabricate the brace using a 3D printer. The result — a customized digit orthosis.

Deng said the students gained valuable skills in the Fab Lab using different 3D design software and printers, learning 3D printing technology and evaluating various materials and machines.

“When they need to use 3D printing technology to develop any sort of manufacturing processes or products in the future, they will have gained good perspective,” he said.

“I wanted the students to understand the entire cycle of research, product development, prototyping, fabrication and testing,” he added. “It gives them good experience for any kind of engineering project, taking it from an initial step all the way to the end.”

“I gained a lot of experience with 3D modeling and 3D printing,” Lyons said. “Now I know so much more about the fine details, requirements and potential materials. I gained a lot of insight into the clinical side of orthotics, too.”

While this project was a second choice for Wolin, who was placed on the team after his first group was split up, he said, “Working on this project has been a great experience and the faculty in the Watson Fab Lab and our project advisors have been a great help.”

“Having Jane Bear-Lehman as an advisor was very helpful; her insight into the clinical process really drove our design into a more realistic and successful approach,” Lyons added. “She ensured we kept the patient and the end goal in mind, instead of thinking only like an engineer.”

All four students and both faculty advisors agree: Working across departments was a significant benefit — and a lot of fun!

“I highly recommend collaborations among different disciplines,” Mitchell said. “After college, we will be going into the real world working on teams consisting of individuals with different backgrounds. This is beneficial because it exponentially increases the probability of creative innovation.”

“This has been a wonderful experience,” Bear-Lehman said. “And, I’m excited because it’s just the beginning.”

“Jane brought a lot of knowledge and experience, and it was a good collaboration,” Deng added. “We talk together very often and we spark ideas.”

One of these ideas already has Bear-Lehman and Deng working together again. The two are speaking with an orthosis material supplier about the possibility of adding commercial materials suitable for 3D printing to its product line.