Design and technical validation of a low-cost, titanium sheet metal TORP (SM-T) for manufacturing and use in LMICs

OBJECTIVES: Total ossicular replacement prostheses are commonly used to restore hearing in the conductive hearing impaired. However, total ossicular replacement prostheses are expensive and scarcely available in low- and middle-income countries. Therefore, the aim was to develop and validate an open-source design of a total ossicular replacement prosthesis that can be produced locally for low- and middle-income countries hospitals. METHODS: Based on input from literature and clinicians a design was made and verified. Accuracy, re-bending safety, cadaver ear fitting, sound transmission and production learning curves were tested. RESULTS: A titanium sheet metal total ossicular replacement prosthesis, costing 9 euro, showed accurate dimensions, surgeons showed short learning curves, and sound transmission was similar to commercial total ossicular replacement prostheses. Re-bending tests demonstrated bending corrections could be safely done. Good cadaver ear fitting could be demonstrated, without conflicts between the titanium sheet metal total ossicular replacement prosthesis and anatomical features. CONCLUSION: The titanium sheet metal total ossicular replacement prosthesis design has proved to be feasible for implementation in low- and middle-income countries.