Solution

Using the findings of our customer discovery from the physical therapists, orthotists, orthopedic surgeons and users (about 200 interviews), we realized there are three major unmet needs described by the patients and their parents: 1) being compact at the foot; 2) having a softer and more breathable approach to reduce skin damage; 3) modularity and scalability to account for changes in growth and functional ability. Additionally, there were two main areas of improvements desired for current AFO designs, suggested by clinicians and practitioners: 1) a smarter powered design to promote natural ankle motion and reduce adverse musculoskeletal and neural adaptations; 2) adding a training feature to provide some of the basic but critical physical therapy exercise training outside of the clinical setting. Accordingly, our proposed powered AFO, DE-AFO, is the first soft, lightweight, and smart AFO with acoustically noiseless operation.

DE-AFO, is a light, noiseless, soft, and smart powered AFO, for children with CP with Gross Motor Function Classification Score (GMFCS) II and III, who need assistance with limited yet existing ankle mobility.

This device uses artificial muscles for motion correction and assistance. These novel actuators, are soft, lightweight, compact, and acoustically noiseless actuators, with muscle-like behavior. The softness and noiseless operation of these artificial muscles will substantially improve the comfort and natural feel of the device, especially around the ankle.

The softness and noiseless operation of DE-AFO will substantially improve its comfort, natural feel and user acceptability. These features may substantially improve user compliance. The enhanced comfort in our design combined with the active assistance of the artificial muscles will increase the users' mobility, social integration, and thereby, improve their quality of life.

DE-AFO has 3 outstanding features:

1. Compact at the foot. Using this feature, increases the flexibility of using the child’s correct shoe sizes rather than bulky oversized shoes required to fit traditional AFOs that further hamper walking ability. Of great importance to children, the smaller DE-AFO profile will allow them to select their preferred shoe styles. By being soft and having a longitudinal contraction, the artificial muscles can follow the morphology of the ankle muscles. This feature, in combination with a cable-driven actuation system, allows a low-profile foot segment.

2. Modularity and scalability. Due to the subject-specific deviations and deformities in individuals with CP, the orthoses design should be flexible in the intensity and location of assistance, which is in contrast to the design of most AFO's. The DE-AFO’s modularity provides the orthopedic physicians and orthotists, the flexibility to custom fit the device to each patient. Additionally, this feature allows the replacement of specific components to accommodate for wear and tear of the device, growth and changes in functional ability of the child. This scalability is highly important, especially for the pediatric population, because their growth-rate and level of activity necessitate one or two conventional AFO replacements each year. Thus, a scalable modular product will substantially reduce the costs associated with buying and fitting multiple AFOs.

The foot-plate will be 3D printed, using light weight plastics, based on the subject's deformities. The insertion point and power of each artificial muscle, and their activation pattern can be adjusted individually; finally, the stiffness of the detachable support-rod, will be adjusted to subject’s size and maximum required passive assist. The sturdy and provide passive assist during push the support-rod will be manufactured using carbon-fiber.

3. Promoting natural motion of the ankle. This promotion is provided by the gait phase detection-driven artificial muscles. By detecting functional segments of each stride (to consecutive steps), known as gait phases, DE-AFO can activate the artificial muscles in synchrony with ankle's skeletal muscle.