Design Considerations for Body-Powered 3D Printed Prostheses with String Mechanism for Upper Limb Disarticulation

Abstract

In medical field, a prosthetic implant is an artificial device that replaces a missing body part/organ, which may be lost through trauma, disease, or a condition present at birth. Prostheses are intended to restore the normal functions of the missing body part therefore, it is essential to design and fabricate them as per the patient's specifications. This requirement of fabricating customized prostheses is an important issue that needs to be addressed. Moreover, In the case of children, there is a need for a periodical change of prosthetics due to the growth of their bones. These situations pose difficulty in adaptation of prostheses for the economically weak and rural area patient’s. 3D printing technology provides a platform to fabricate any complex shaped polymeric parts economically with ease. This capability of the technology can be utilized to fabricate customized and patient-specific prostheses. The present paper discusses the process flow that can be adopted for designing and fabricating a patient-specific prosthetic hand using extrusion-based 3D printing technology. The design considerations for 3D printing of a body-powered prosthetic hand with all tolerances and clearances are discussed with the help of a case study. A provision for string and the elastic based mechanism is provided to deliver motion and action to the fingers. By appropriately applying the design considerations, 3D printing technology can be effectively utilized for the fabrication of economical prosthetic hands.