Piston finger device for restoring the motor function of chronic plegic fingers: Development of the device and verification of the effectiveness

A piston finger technique (PFT) was developed for restoring the motor function of chronic plegic fingers with good outcomes, including reduced spasticity and improved muscle shortening. In our previous work, we analyzed finger motions during treatment with the PFT using a motion capture system. Based on the motion analysis results of treatment with the PFT, we determined the required specifications for a piston finger device (PFD). In this study, we developed a PFD utilizing a crank mechanism. We conducted treatment with the PFD on five patients with chronic plegic fingers. The assessment results based on the Modified Ashworth Scale, the Fast Passive Stretch, and the Passive-ROM (Range Of Motion) before and after treatment with the PFD showed that motor function was improved and abnormal muscle tone had decreased. Therefore, the effectiveness of treatment with the PFD was verified.