Joan Sanders, PhD: Linking Creative Thinking with Practical Application
September 2013 Issue
Joan E. Sanders, PhD, has been interested in science and mathematics ever since she was young. "I especially loved doing experiments, and when I was a child I was always building mechanical things," she recalls. "When I went to college I got interested in engineering and biology; most of my work was in bioengineering. I had a strong interest in the healthcare field and figured I could use my skills as an engineer to help solve problems in biomedicine."
It is at this convergence of engineering and biology that she has found her niche. As her scientific imagination soars, Sanders has reached new levels of creativity; in her more than two decades of research, she and her colleagues have added much to clinical practice in several aspects of healthcare.
Sanders, a professor in the Bioengineering Department of the University of Washington (UW), Seattle, focuses on research not only in prosthetics but in such areas as tissue engineering for heart valves and other cardiac applications, and designing fibro-porous materials for medical applications. "At UW, I and most of my colleagues are involved in research on micro-level biomaterials and tissue-materials research at the cellular level," Sanders explains. "I have two directions in research: biomaterials and external prosthetics."
Sanders was born and grew up in the Los Angeles, California, area. She earned her bachelor's degree in mechanical engineering from Stanford University, California, in 1983, and then attended Northwestern University, Evanston, Illinois, where she was awarded her master's degree in mechanical engineering in 1985. For her degree project, she performed a fluid mechanics analysis of a high-pressure needleless syringe, like those used in insulin injections. "The medical personnel were having trouble injecting drugs under the skin properly, and I figured out what the problems were," she says.
She then went to UW, where she earned her doctorate in bioengineering in 1991. A faculty member had suggested that she might be interested in external prosthetics and urged her to meet Ernest Burgess, MD, PhD, founder of the Prosthetics Research Study (PRS), who had devoted his career to amputee care and prosthetics research, with a view to aiding individuals with amputations in developing countries. Prosthetics captured Sanders' imagination as did tissue-medicine research, and she worked for PRS from 1990-1993 while earning her doctoral degree. "Dr. Burgess supported me [during] the last years of my PhD," she says. "Then UW offered to hire me as a faculty member, and I've just kept on going from there. Interest has really grown in prosthetics," she continues. "It's just a great environment with a lot of really good students and a lot of support."
While pursuing her education, Sanders also held several teaching and research assistant positions, along with a variety of other interesting jobs including a stint as a wrangler for the Beartooth Ranch, Nye, Montana; running her own business as a sports photographer in Los Angeles, California; serving in a public relations position with the Stanford Athletic Department; being a research engineer with Baxter Travenol Laboratories, Round Lake, Illinois; and working as an engineer with Tyler Builders, Los Altos, California.
Sanders' resumé in prosthetics-related research and innovations published in scientific journals dates back to 1990, starting with a measurement device to aid prosthetic fitting, and she is currently busy with several projects as a principal investigator or co-investigator. Prosthetics research being done in Sanders' UW lab focuses on residual-limb volume fluctuation, advanced socket fabrication, interface materials, and portable technologies. With her engineer's eye to adapting scientific findings to practical solutions, Sanders and her team have created several applications to aid prosthetic clinicians, patients, and manufacturers as well as researchers.
Monitoring Residual-Limb Fluid Volume Changes
A research team headed by Sanders recently developed a device to track the residual-limb fluid volume fluctuations within the prosthetic socket as prosthetic users go about their daily activities. The monitoring device provides data that can tell the prosthetist what residual-limb volume changes that particular patient is likely to experience throughout the day. The prosthetist can then work with the patient to use prosthetic designs and strategies to minimize the impact of residual-limb volume changes on the patient, Sanders explains.
Longer term, the device may help in understanding how to design more robust, flexible "smart" prosthetic sockets that accommodate daily residual-limb volume fluctuations without discomfort and inconvenience, according to a July 23 UW press release. (Author's note: For more information, visit www.oandp.com/link/228)
Matching the Liner to the Patient
Many prosthetists limit their prosthetic liner selections to the few that they are familiar with through clinical experience, since the differences are often ambiguous, Sanders points out. The webbased Prosthetic Liner Prescription Assistant (PLPA) she and her colleagues designed presents materials-testing data of various manufacturers' liners in a format that allows easy comparisons of such material properties as stretch resistance, volume accommodation, shear resistance, and adherence. Thus, prosthetists can gain knowledge about an expanded array of available liners and optimize available choices to their individual patients' needs.
A presentation by Sanders and colleagues at the 2013 Annual Meeting & Scientific Symposium of the American Academy of Orthotists and Prosthetists (the Academy), and included in the Journal of Proceedings, describes the PLPA: "Liners are grouped into percentile brackets (20-percent increments) for each metric. Higher ratings do not mean higher quality. Instead, they indicate that a liner has a more accentuated material property. Pop-out pages describe individual tests as well as their practical importance." (Author's note: To access the PLPA, visit depts.washington.edu/plpa)
"Manufacturers are interested in our findings and often ask just how we do our testing so they can duplicate it," Sanders adds. "It would be great to establish a standard for characterizing these materials and that is what we hope to accomplish. Right now, manufacturers do their own tests and every test is different; users can't compare materials."
Cost Center Evaluates CAD/CAM Shape Quality
Sanders and her team have also created a cost center at UW to evaluate the shape quality of prosthetic sockets and models fabricated by computer-aided manufacturing (CAM). For just the cost of testing and preparing the reports, outside researchers, clinicians, industry sources, prosthesis users, or others can send in their sockets or models for Sanders and her team to compare against the electronic file shapes used for manufacturing.
According to the cost center website, these accuracy comparisons can be used to:
- Provide information to improve equipment performance and thus enhance socket quality.
- Evaluate consistency of performance at a clinic, fabrication center, or other treatment facility.
- Verify socket-shape quality as a well-controlled variable in research investigations.
Tracking Prosthetic Sock Changes
"We have developed a device that measures the socks a person is using at a particular time," Sanders says. "It's difficult for patients to remember what socks they were wearing during different activities throughout the day when their prosthetists ask about socks relative to socket fit and limb volume changes. This device keeps track, so patients don't have to write this down all the time."
The device uses radio frequency identification (RFID) technology and continuously monitors sock use. Laboratory testing on three participants with transtibial amputations showed that the device correctly monitored sock presence during sitting, standing, and walking when one or two socks were worn but was less reliable when more socks were used, research by Sanders and her colleagues reveals. Using ultra-high-frequency RFID may overcome these limitations, according to their technical report appearing in the Journal of Rehabilitation Research
& Development, published by the Department of Veterans Affairs (VA) Rehabilitation Research & Development Service (www.rehab.research.va.gov/jour/2012/498/sanders498.
html). "With improvements, the technology may prove useful to practitioners prescribing volume-accommodation strategies for patients by providing information about sock use between clinical visits, including timing and consistency of daily sock-ply changes," the report states.
Sanders has enjoyed many career highlights. Upon reflection, she lists "going to the Academy meeting and getting feedback from the practitioners" among them. "They are very appreciative of our work and use it; that helps keep us going."
In terms of research, she says one of her most rewarding moments was when the UW research team's instrument to measure residual-limb-fluid volume finally began working and producing useful information after months of effort. "It was about two years before it produced reliable data, so the day we saw useful information coming out of it was a big one!"
Designing measuring instruments and other research projects can take much work and many adjustments before the exhilaration of achieving success, Sanders notes, and when that happens, "it's exciting for us and for the students, too. They catch the energy." Mentoring students has also been an important part of Sanders' career. Her efforts were acknowledged when undergraduate student members of the UW Golden Key National Honors Society presented her with the Honorary Faculty Member Award in 1995 and when she received the University Faculty Mentor Award from UW in 1998.
Sanders' research activities have resulted in a large body of published journal articles along with numerous presentations at professional meetings. She is co-holder of more than 12 patents plus several copyrighted software programs. Her service to various professional organizations includes a stint as the associate editor of IEEE Transactions on Rehabilitation Engineering as well as serving as a peer reviewer on several engineering and healthcare-related journals.
Sanders' accomplishments have also garnered numerous awards. In the prosthetics area, the Academy honored her with its Research Award during the 2011 Annual Meeting & Scientific Symposium in Orlando, Florida. She also received Thranhardt lecture awards in 2010 and 2013.
Sanders has had a lifelong love of sports and is an outfielder on the Seattle Diamonds women's baseball team, but the light of her life is her son Ben, 12. Ben is enthusiastic and knowledgeable about his mother's work. In fact, when he was in kindergarten, Sanders was showing his class how a prosthetic leg works, but Ben was so excited he carried on the rest of the presentation himself, she recalls. He is also a talented dancer and theatrical performer who has already been in some major theater productions in and around Seattle. Sanders enjoys accompanying him to his numerous performances. She and Ben also enjoy horseback riding together and other outdoor recreation.
"Engineering is the creative application of scientific principles used to plan, build, direct, guide, manage, or work on systems to maintain and improve our daily lives," according to the National Society of Professional Engineers. Joan Sanders has enthusiastically fulfilled that role, and the prosthetics profession can look forward to the benefits her future work will bring.
Miki Fairley is a freelance writer based in southwest Colorado. She can be contacted via e-mail at