Application
For individuals who are missing part of an arm, a prosthesis may be attached to the arm remnant via a socket. Many socket designs achieve the primary goal of attaching the prosthetic arm, but present issues to the amputee that result in reluctance to wear the prosthesis. Non-permeable full-contact sockets, for instance, tend to be uncomfortably hot and humid, while open socket designs are more breathable, but are bulky and unaesthetic. Many close-fitting designs are difficult to put on and take off, while looser designs may not be sufficiently stiff to support the arm remnant. Ideally, the socket connecting the artificial arm to the arm remnant should be close-fitting, comfortable to wear, easy to put on and take off, adjustable, lightweight, and self-suspending, among other characteristics.
Key Parameters and Requirements
At Eindhoven University of Technology, a master’s degree candidate was interested in developing a design for a transradial (that is, below the elbow) socket that improved on earlier designs while taking advantage of recent advances in materials.1 The thesis project explored several different options for socket design and material selection, ultimately narrowing down viable choices to three designs. The researcher examined how well each of the three designs met 13 different requirements gleaned from patient surveys, assigning each design a superscore.
Results
A stainless steel wire mesh socket was identified as the best of the three transradial socket designs, because stainless steel does not irritate the skin, the mesh design allows for breathability, the socket can be designed to be close-fitting and self-suspending, and the wire mesh prosthetic should be easy to put on and take off. The design calls for the wire mesh to be shaped by forming it around a wooden sphere. The edges of the wire mesh are joined together with adhesive and then covered with a polyurethane strip. In joining the edges of the mesh, the adhesive must fill all gaps in the overlapping edges. A standard prosthetic arm shell is attached to the spherical mesh via a polyurethane strip that is glued to the mesh. Master Bond EP42HT-2ND2Med Black was selected as the adhesive to join the stainless steel mesh edges together, to join the polyurethane strip to the stainless steel mesh, and to attach the closure to the mesh. EP42HT-2ND2Med Black met the requirements for joining the plastic and metal materials, filling the mesh gaps, and not irritating the skin.
Conclusion
Prosthetic and fully implantable devices face unique environmental challenges. All materials that come into contact with the patient must not harm the patient, and the device must operate flawlessly while subjected to motion and surrounded by physiological materials. Medical device manufacturers and researchers count on biocompatible Master Bond EP42HT-2Med and EP42HT-2ND2Med Black to assemble and protect medical devices while ensuring patient safety.