Design and fabrication of a novel 4D-printed customized hand orthosis to treat cerebral palsy

This research study is dedicated to additive manufacturing of the shape memory polymer hand orthosis to treat patients with cerebral palsy. The treatment process for cerebral palsy is a step-by-step process that needs different adjustments for the spastic hand to stretch it towards a normal posture, whereas meeting these requirements using conventional methods or complicated mechanisms is expensive, less flexible, time-consuming, and less practical. A comprehensive investigation was conducted to design and fabricate novel thermally actuated customized hand orthosis via digital light processing (DLP). The highly precise scanning device was used to derive the hand model, and subsequently, the Blender software was used to design the customized orthosis. The results showed that fabricated orthosis could represent a strong potential to become an alternative treatment for cerebral palsy. The shape memory actuation of the orthosis indicated that 100 % shape recovery is achievable in different actuating conditions with recovery temperatures higher than 55°C. Besides, it was found that the response time and shape recovery percentage could be tailored in the range of 5 to 40 s and 45 to 100%, respectively, by adjusting programming and actuation temperatures. Further, the repeatability of the shape memory effects in the printed orthosis was investigated as well, which proved that until 17 repetitions, 100 % shape recovery was achievable.