Students Design Oberstar's Hip Injection Trainer

From left to right are project advisor Adam Choe, MS,
student Trevor Laughlin, project sponsor Jennifer Oberstar, MD,
students Nathan Stob, Daniel Sherman, and Rachael Brandt.

Jennifer Oberstar, MD, offered University of Minnesota senior mechanical engineering students to design a hip simulator as a way to teach learners how to do ultrasound-guided hip injections. The project was proposed in Fall 2016 to undergraduate students in the capstone senior engineering design course where teams of four to six students work for one semester on an engineering design project that’s sponsored by a local company or UMN researcher. Students then present their projects at the course’s Design Show at the end of the semester.

The students who worked on the hip simulator were Dan Sherman, Nathon Stob, Rachael Brandt, and Trevor Laughlin. Oberstar was the sponsor of the project, and Adam Choe, MS, from the University of Minnesota Medical Devices Center, was the project advisor.

“I thought the students produced an excellent prototype in the three months provided,” Oberstar said. “At the start of the project, the students were unfamiliar with the procedure and how to use ultrasound. They worked well as a team and were thoughtful with their design.”

The hip injection trainer project was offered to students because it required engineering knowledge and was an opportunity for a “real world” application. Projects with “real world” applications are more engaging for learners, and Oberstar also saw that this was an opportunity to collaborate across disciplines.

According to Oberstar, the prototype will now be introduced to experts performing ultrasound-guided hip injections. Further research will be conducted to validate the prototype. Adjustments to the current device may occur after input from faculty and learners.

The Hip Injection Trainer was funded by the Department of Family Medicine and Community Health Discovery Fund. Oberstar received funding in 2016 to develop training for family medicine residents to further hone their skills in ultrasound-guided hip injections.

HOW IT WORKS

Injection site

The injection site was created with low-hardness silicone and tactile mutilator additives to create a medium that looks and feels like human tissue when injecting under ultrasound.

In addition, each injection site contains a conductive textile, which signals the boundary of the target injection area.

Body

The lower body of the hip injection trainer contains two injectable hips molded into moderately hardened silicone.

The upper body is composed of lower-hardness silicone with the same approximate density as human muscle tissue.

Feedback system

The electronic feedback system of the hip injection trainer contains a red light-emitting diode (LED) and green LED, signaling a failed or successful injection, respectively.

A learner injects the injection site, and when passing through the conductive textile located in the bottom of the injection site, a circuit is completed, signaling a successful injection. However, no LEDs are lit until the learner depresses the plunger on the needle, signaling a finished injection.

From left to right are students Trevor Laughlin, Rachael Brandt, Daniel Sherman, and Nathan Stob.