PRORP 2011 Investigator Vignette

Title: An Exotendon Orthosis to Improve Mobility for Military Personnel Recovering from Combat-Related Injuries

Investigator: Brian Glaister, Peer-Reviewed Orthopaedic Research Program, Cadence Biomedical

We have two grants from the PRORP. One is for a sensory feedback prosthesis and this is a technology that's still early in the development, but is something that we came up with in close consultation with physical therapists that are working with amputees every day trying to teach them how to walk again.

The main problem that amputees face after they have their amputation surgery is it takes about 38 visits to a physical therapist and an occupational therapist to learn how to walk and the big issue they have to overcome is that they can't feel when their foot hits the ground anymore. So we're developing a prosthesis that can provide them sensory feedback so they can feel when the foot is on the ground and understand how the pressures in the socket relate to their body position related to their foot so that they can start to walk with confidence instead of looking at the ground to make sure their foot is firmly planted on it.

To generate the vibration we'll be using just common unbalanced motors that are in your cell phones that make them vibrate. There will be a number of sensors on the foot and depending on how the pressure is distributed, different vibration stimuli will go in different areas in the socket. So if you're leaning too far to the right, the right side of your socket will buzz. If you're too far to the left, the left side and so they can start to correlate the vibrations with the different pressures that the skin feels in the socket so that you can take the vibrations away and the patient will be able to discern if they're leaning too far to the left or too far forward without the vibrations as well.

Our second grant is for what we call our Kickstart™ Kinetic Orthosis. And this is geared towards people with severe lower extremity weakness due to a neurological injury like a stroke or a spinal cord injury or a degenerative neuro-condition like Lou Gehrig's disease or multiple sclerosis or muscular dystrophy. And the way the kinetic orthosis works is that it has a long spring that goes from the hip to the ankle and when somebody starts to take a step the spring stretches and stores energy. And then at the end of the step all that energy comes back and it can help propel the user forward and lift their leg off of the ground in preparation for the next step.

So there's nothing on the market right now that can assist with ankle plantar flexion and with hip flexion. And these are the two functions most severely impaired by a neurological injury Orthoptists can stabilize weak joints for these patients but there's nothing to help them overcome these weaknesses particularly in the hip flexors. So when we put this device on really impaired patients, suddenly they're able to take longer steps, they're able to walk faster, they're able to walk longer and through that process we hope that many of them can actually recover function and improve their outcomes.

It's been quite miraculous for-for many patients. We just put a device for a man with a spinal cord injury a couple weeks ago and he's been working for 6 years to regain just a little bit of function. He's walking in the parallel bars and without Kickstart he can only take about two steps before his legs give out. And he's stuck; he can't go any further.

But with Kickstart, he was doing laps in the parallel bars. We had a woman with Lou Gehrig's disease and when we started with her she could only walk for about 5 minutes and only if her husband held her arm. She's been using Kickstart for about 6 months. She can walk on a treadmill for half an hour. She can walk across a room without her husband and without Kickstart now and on New Year's Eve she was able to dance for two and a half hours. And that's just remarkable, remarkable progress.

The DoD Program is great because they take risks on young investigators whereas other federal funds tend to go to very established investigators. It's really important to put funds behind early-stage projects that aren't fully developed because that's where the new technology is, where the new innovation, where the new impact can be had. Certainly as an entrepreneur, this was a huge bonus for us. It gave us a lot of credibility with investors to know that we have something like the Department of Defense behind us and we're just not out here on an island by ourselves.

We spent a lot of time tinkering with the technology and getting it to the point where it was working repeatedly. But the first few times we put it on somebody, it was always hold your breath and cross your fingers and hope that it behaved the way it's supposed to. And when we marry the technology with a patient and it works and you see their eyes light up and they start to think about new possibilities for their life. That makes all the hard work worth it.