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Steinhoff Prosthetic Research Initiative: The New Mexico Tech SPRI Hand Project

A person’s life can be irrevocably changed in a moment. Mundane tasks like tying shoes, fastening a necklace, or using a knife during dinner, become extraordinary challenges. Most of us are fortunate and do not have to imagine dealing with such obstacles. But for our friend, colleague, and fellow alum Edie Steinhoff, this scenario became a reality last November when a kitchen DIY project went horribly wrong. In a dreadful accident with a table saw, Edie cut off all of the fingers and the thumb on her left hand.

Gina Chavez, long-time friend of Edie and fellow Tech employee, was at home that Sunday morning. She answered a knock on the door, and discovered Edie in shock and bleeding profusely. Stunned, Ms. Chavez had her daughter drive Edie to the local hospital, while she raced to retrieve the fingers, place them on ice, and rush them to the hospital. Thanks to this quick reaction, Edie’s life was saved. But the fate of her hand was uncertain. 

Edie and the severed digits were transferred by ambulance from Socorro to University of New Mexico Hospital (UNMH), where Dr. Deana Mercer, an Associate Professor of Hand Surgery in the Department of Orthopedics and Rehabilitation at UNM, re-attached the middle finger and thumb. The thumb was very damaged by the saw but the team attempted to salvage it, because it is so important to hand function. The middle finger re-attachment survived, but the thumb was too damaged and did not survive. It had to be removed on November 22, 2016. In the remaining finger, the tendons have now fused to the bone; the finger’s joints do not function. The pain from the nerve damage can last for years, Edie said, adding that wearing a compression sleeve does help.  

Many people would think that this would be the end of their career. Not Edie, who only missed eight days of work before returning to Brown Hall, where she is a graphic artist and the Marketing and Publications Coordinator for Tech’s Communication Office. Edie has been at Tech for over sixteen years, since she moved to Socorro from South Carolina in October 2000. She has a Bachelor’s of Fine Arts, with a concentration in Graphic Design, from Texas Woman’s University, and a MBA with a concentration in Marketing.

Upon arriving at Tech, Edie said she was so impressed with the quality of Tech students that she joined them, receiving a B.S. in General Studies in 2007, “so I could be one of the smart kids, too.” Edie is well known for her work with student organizations; she is an advisor to Paydirt and to Alpha Sigma Kappa–Women in Technical Studies. She has won two Student Appreciation awards from the student body. In her neighborhood, she has opened her heart and her home to rescue homeless cats.

New Mexico Tech, being a close-knit and caring community, immediately rallied around Edie. Her many friends and colleagues sent emails of encouragement while she was in the hospital, and offered to help in any way that they could once she was home. Friends fed her pets; they folded her laundry – all without ever being asked. Edie said she felt humbled by the outpouring of support from the community.

Colleen Foster, Director of Advancement and one of Edie’s close friends, felt driven to find solutions to help her regain some of the abilities that she lost due to the accident. She knew that Edie had friends across the Tech network. Ms. Foster shared the news of Edie’s accident with long-time supporters of New Mexico Tech, who anonymously and generously donated $53,000 towards research to build Edie a new hand. Ms. Foster also knew that the university had the technical expertise to help Edie. 

Enter Dr. David Grow, an Associate Professor of Mechanical Engineering who joined the Tech faculty in 2011 and now directs Tech’s Robotic Interfaces Lab. Dr. Grow came to Tech with his Ph.D. in Mechanical Engineering from Johns Hopkins University. Four years ago, he worked with teams of students on a Sandia-sponsored project to improve user feedback when wearing a computerized above-knee prosthetic marketed under the name C-Leg by the Germany company Ottobock.

Prosthetic devices have been around for a while in one form or another, and movie watchers are familiar with the type used by Captain Hook in “Peter Pan.” According to Dr. Grow, there is a wide selection of prosthetic devices now available, including special-purpose hands for rock climbing, fishing, office tasks, and other activities. Much of the current technology benefits from the creation of the “DARPA hand,” the research platform that was the product of the “Revolutionizing Prosthetics” project by the Defense Advanced Research Projects Agency (DARPA).  But state-of-the-art prosthetic hands are prohibitively expensive.

“There are organizations trying to change that, to make prosthetics more accessible,” Dr. Grow added.  For instance, 3-D printing paired with simple cable controls allows for a surprisingly functional device at a low cost. 

The Steinhoff Prosthetic Research Initiative, otherwise known as the New Mexico Tech SPRI Hand Project, seeks to advance the technology of prosthetic hands, and improve the accessibility and availability of these devices. The first priority is developing different versions of the prosthetic hand for Edie, who will be an integral part of the research team as she tests each variation of the device.

The second priority is to expand Dr. Grow’s research to help underserved populations, such as women, children, and people living in rural areas. Most prosthetic devices are designed for men because injuries of this nature are typically the result of military and industrial accidents. 

Members of the all-volunteer student research team are graduate student Benjamin Bean (software design), Mechanical Engineering seniors Andrew Duff and Ben Sears (mechanical design), and juniors Chris Schmittle (sensor and actuator selection) and Rebecca Sappington (3D printing and “design for manufacturability”).

This five-member student design team began work in the summer of 2017 and continues working on the project.

Dr. Grow said. “There’s been such an interest, I’ve had to turn down students,” he said, adding that the more money raised, the greater number of students can get involved.

The project to design a prosthetic device, or sleeve, for Edie “hits a sweet spot for us,” Dr. Grow said, adding that much of the robotics research pursued in his lab has clinical relevance. The challenge is designing a prosthetic hand that is lightweight, durable, waterproof, and cost-effective, for starters. Then there are the aesthetic and functional aspects to consider.

Ideally, Edie would be fitted for two devices – an aesthetically designed hand she could put on in the morning for regular day-to-day interactions (“my Audrey Hepburn hand” as Edie referred to it); the other - more of a work hand, a function-first design that allows fine control for as wide a range of activities of daily living as possible.

Fortuitously, Dr. Grow and Edie’s surgeon, Dr. Mercer, already share a strong research collaboration (Dr. Grow is an adjunct faculty member in Department of Orthopedics at UNM). His collaborators there also include Dr. Christina Salas and her students, who intend to assist with this project by creating a detailed model of Steinhoff’s hand, allowing a custom-fit for the prosthetic devices.

The design team has been meeting weekly for several months. They have access to a 3D printer that Dr. Grow said has sufficient resolution to make printable parts.

“You can design components knowing the limitations of the printer,” he said. In Edie’s case, the focus is on certain parts of her fingers.

“There are synergies in how the hand moves,” he said. “In principle, you need to control 22 movements, but we will only need to control a smaller set of movements,”

The concept involves principle component analysis. The goal is to determine a reasonable number of sensors that could be integrated into an arm sleeve. For Edie, he said, the ideal scenario would be a “cool” prosthetic or sleeve where control of the prosthetic hand would be intuitive. 

Advancement Director Foster said,  “This is such a unique opportunity for our students to work on a research project where they will actually see the difference they’ll make in people’s lives.”

Although Edie admits that her life will never be the same, she envisions SPRI as a mechanism to help others with prosthetic needs. For herself, Edie wants her device to be simple, so that most of the money raised will to go to the research.