Restoring hearing using total ossicular replacement prostheses – analysis of 3D finite element model

CONCLUSIONS: During total ossicular replacement surgery, a better auditory functional recovery is obtained when the stapes footplate is retained. Also, the best hearing restoration is obtained when the total ossicular replacement prosthesis (TORP) is placed onto the center of the stapes footplate during operation. OBJECTIVES: The effects of TORPs connecting to different positions of the stapes footplate or oval window membrane on hearing restoration were investigated. METHODS: A healthy volunteer's right ear was scanned to obtain the CT data, which were digitalized using a self-compiling program and imported into PATRAN software to establish a 3D finite element model, and a harmonic response analysis was carried out using NASTRAN software. Then the effect of TORPs connecting to different positions on the stapes footplate or oval window membrane was studied. RESULTS: The displacement curve of the stapes footplate was in good agreement with that of the normal ear when the TORP was connected onto the center of the stapes footplate. The best hearing restoration was obtained when the TORP was placed onto the center of the stapes footplate. The displacement curve of the stapes footplate was basically equivalent to that of the normal ear when the TORP was connected onto the anterior site, while the displacement curve of the stapes footplate differed from that of the normal ear when the TORP was connected onto the posterior site. In addition, when the TORP was connected onto the oval window membrane, the displacement curve of the stapes footplate was different from that of the normal ear.