Development of Patient-Specific Adaptive Assistive Devices for Brachial Plexus Injury

Abstract

Injury to the brachial plexus prevents the arm, wrist, and hand from communicating with the spinal cord in whole or in part. The 'patient's upper arm limb appears to be completely incapable of performing any type of independent movement. The aim of this project is to design and develop a customized adaptive assistive device for patients with brachial plexus injury and to fabricate the prototype using 3D printing technology. The development of the device involved adapting the mechanical engineering design process, including conceptual design and finite element analysis, to predict the performance of the design and to select the best printing materials. The patient's left arm was 3D scanned to create a customized part that perfectly fit the patient. The 3D model of the prototype was developed using Autodesk Fusion 360 and Autodesk TinkerCAD. Two different materials, namely Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS), were considered in the computational analysis. Results show that the maximum von Misses stress of PLA is observed at 2.464 MPa, slightly higher than the ABS material (2.451 MPa), indicating a greater stress tolerance imposed on the material's strength. However, PLA has a smaller maximum displacement than ABS, at 0.019 mm and 0.030 mm, respectively. The PLA material was chosen for 3D printing based on several considerations, including mechanical qualities, cost, printing time, durability, and data evaluation. The adaptive device for brachial plexus injury was successfully delivered to the patient and demonstrated the capability to assist in arm movement.