PURPOSE: To investigate the motion of prostheses used to reconstruct ears with an absent stapes arch. STUDY DESIGN: We have studied the motion of conventional total ossicular replacement prostheses (TORPs) and a novel incus-stapes replica prosthesis (ISRP), which connects the malleus head to the footplate, during changes in middle ear pressure (+400 to -400 dPa) in fresh human temporal bones using digital video clips and photographs. The pressure in the (sealed) external auditory meatus was varied using a manual tympanometer. The displacements of the prostheses in the medial to lateral plane have been measured using the dimensioning tool of Corel Draw. RESULTS: During changes in static pressure, TORPs move more in the lateral to medial plane than ISRPs. The motion of ISRPs is similar to that of the intact ossicular chain. CONCLUSION: The ISRP design is less likely to damage the cochlea during changes in static pressure than a conventional TORP, but the maximum medial displacement of the TORPs studied was less than 0.1 mm.
PURPOSE: To investigate the motion of prostheses used to reconstruct ears with an absent stapes arch. STUDY DESIGN: We have studied the motion of conventional total ossicular replacement prostheses (TORPs) and a novel incus-stapes replica prosthesis (ISRP), which connects the malleus head to the footplate, during changes in middle ear pressure (+400 to -400 dPa) in fresh human temporal bones using digital video clips and photographs. The pressure in the (sealed) external auditory meatus was varied using a manual tympanometer. The displacements of the prostheses in the medial to lateral plane have been measured using the dimensioning tool of Corel Draw. RESULTS: During changes in static pressure, TORPs move more in the lateral to medial plane than ISRPs. The motion of ISRPs is similar to that of the intact ossicular chain. CONCLUSION: The ISRP design is less likely to damage the cochlea during changes in static pressure than a conventional TORP, but the maximum medial displacement of the TORPs studied was less than 0.1 mm.