Mechanisms and Prevention Strategies of Prosthesis Extrusion in Ossicular Chain Reconstruction

Ossicular chain reconstruction restores sound transmission between the tympanic membrane and the inner ear, but prosthesis extrusion remains an important cause of long-term failure. Its incidence may be underestimated because many studies have limited follow-up. This narrative review summarizes current evidence on the mechanisms and prevention of ossicular prosthesis extrusion. A structured literature search was performed in PubMed, Web of Science, and Embase. Clinical, animal, histopathological, finite element, temporal bone, and in vitro biomaterial studies were reviewed when they addressed prosthesis extrusion, dislocation, interface mechanics, middle ear conditions, or prevention-oriented strategies. Current evidence suggests that prosthesis extrusion is a multifactorial process involving interface mechanical mismatch, reduced dynamic adaptability, altered force transmission, and adverse middle ear conditions. Focal stress concentration at the tympanic membrane-prosthesis interface may contribute to local ischemic or structural injury, although direct clinical proof remains limited. Poor ventilation, chronic inflammation, biofilm formation, fibrosis, and scar contracture may impair tissue repair or disturb prosthesis position, thereby increasing interface instability. Preventive strategies include cartilage interposition, bioactive material or surface modification, dynamically adaptive designs, biomimetic or computationally optimized geometries, and surgical optimization. Cartilage interposition remains the most established clinical approach, whereas bioactive, adaptive, and computationally optimized designs still require long-term validation. Future studies should standardize extrusion and dislocation endpoints and evaluate prostheses that combine interface mechanical compatibility, optimized force transmission, and biological integration.