An evaluation of 3D printable elastics for post stroke dynamic hand bracing: a pilot study.

The rise of 3D printing allows unprecedented customization of rehabilitation devices, and with an ever-expanding library of 3D printable (3DP) materials, the spectrum of attenable rehabilitation devices is likewise expanding. The current pilot study explores feasibility of using 3DP elastic materials to create dynamic hand orthoses for stroke survivors. A dynamic orthosis featuring a replaceable finger component was fabricated using 3DP elastic materials. Duplicates of the finger component were printed using different materials ranging from low stiffness (low elastic modulus) to relatively high stiffness (high elastic modulus). Five stroke survivors with predominantly moderate hand impairment were recruited to evaluate usability and impact of orthoses on upper extremity function and biomechanics. No significant differences in usability were found between 3D-printed orthoses and a commercial orthosis. Increases in stiffness of the 3DP material reduced pincer force ( p  = .0041) and the BBT score ( p  = .043). In comparison, the commercial orthosis did not reduce pincer force but may reduce BBT score to a degree that is clinically significant ( p  = .0002). While preliminary, these findings suggest that a dynamic orthosis is a feasible clinical application of 3DP elastic materials, and future study is warranted.