Novel biological/biohybrid prostheses for the ossicular chain: fabrication feasibility and preliminary functional characterization.

Alternatives for ossicular replacements were fabricated in order to overcome persisting rejections in middle ear prosthetization. Unlike the synthetic prostheses in fashion, we propose biological and biohybrid replacements containing extra cellular matrix (ECM) molecules to improve biointegration. In this study, ECM-containing devices shaped as Partial Ossicular Replacement Prostheses (PORPs) were fabricated reproducing the current synthetic models. Biological PORPs were obtained from human decellularized cortical bone allografts by computer numerically controlled ultraprecision micromilling. Moreover, porous PORP-like scaffolds were produced and cultured with osteoinduced human mesenchymal stromal cells to generate in vitro bone ECM within the scaffold porosity (biohybrid PORPs). The acoustic responses of such devices were investigated and compared to those of commercial prostheses. Results showed that biological PORPs transmit mechanical signals with appropriate frequencies, amplitudes, and with early extinction time. Although signal transmission in biohybrid PORPs showed insufficient amplitude, we believe that tissue engineered constructs represent the new challenge in ossiculoplasty.