Keck School of Medicine of USC professors David Armstrong, DPM, PhD, and Charles Liu, MD, PhD, knew they wanted to work together immediately. “He’s the first guy I saw when I got out of the car at Rancho Los Amigos (National Rehabilitation Center),” explained Armstrong “We’ve been brothers from another mother ever since.”

Armstrong, a podiatric surgeon and Liu, a neurosurgeon, would seem at first to be an unlikely pairing. But the two men clicked on a personal level and soon realized they had a great deal to offer each other as professional collaborators. Both men already were studying how much information a person takes in through the nerves of the feet; how to preserve, repair, or replace that information system; and how nerve damage can affect a patient’s mobility.

“David is interested in metabolic health, mobility and neuropathy — the loss of nerve sensitivity that can occur in patients with diabetes. As a neurosurgeon, I’m interested in lower extremity function and metabolic health too,” Liu explained. “In my work, I think about how to restore mobility to patients who can’t feel their legs. It’s a similar problem to diabetic foot ulcers.”

“We’re meeting in the middle, and it’s fun,” Armstrong said. “It’s so common in medicine for people to silo, but you can’t let your ideas sit there alone. Whatever the other guy is doing will make your thing more interesting.”

While looking for a project to collaborate on, they found a Canadian security company studying the way weight is distributed across the foot while walking. By capturing these pressure signatures — which are as distinctive as fingerprints — the technology could signal if, for example, an unknown person walked into a secure room.

The doctors quickly saw that pressure signatures could be a way to spot changes in gait early on — a potential warning sign of a more serious problem. With their shared interest in wearable technology, Liu and Armstrong steered the company toward a smart insole. The device will flag changes in a patient’s gait, activity level and balance, as well as monitor for the localized increase in heat that can reveal a building infection before the human eye can spot it.

“Those early warning signs can be crucial — the best surgery is the one we never have to do,” Armstrong explained.

With that kind of prevention in mind, the “toe doctor and the brain doctor” increase the functionality of the insole to have it reward patients for increasing their activity or losing weight, make nutritional recommendations, or discreetly remind a patient to get their daily walk in. It has the potential to give patients a sense of greater contact with their care team while reducing the need for physical office visits.

The collaboration caught fire — Armstrong and Liu’s insole tied for first place for the Global People’s Choice Award in T1D Exchange’s Diabetes Innovation Challenge this year.

“Every once in a while, you need to win an award,” Liu joked. “Diabetes is a huge problem in the world. In the tech world, people pitch their ideas. If these technologies are identified as being worthy, you can start to get the support.”

— Lex Davis