Stapes piston insertion depth and clinical correlations.

The insertion of the stapes piston within the vestibule provides the physical basis for a successful stapedotomy. An insertion depth of 0.5 mm is recommended to avoid the dislocation of the stapes prosthesis (e.g. sneezing). The objective of this study is to analyze the depth of stapes prosthesis insertion and its correlation with clinical outcome. We observed in a retrospective case series 39 otosclerosis patients after a stapedotomy and a postoperative performed flat panel tomography/cone beam CT. The evaluation included the radiologically found depth of prosthesis insertion within the vestibule, the vestibule depth, and the correlation with the bone conduction (BC) threshold, vertigo, and tinnitus. Insertion depth varied between 0.2 and 1.6 mm (mean 0.74 mm). The ratio of insertion depth versus the vestibule depth was between 8% and 59% (mean 26.6%). We observed no correlation between the insertion depth, the length of the prosthesis, the ratio of insertion depth/vestibule depth, postoperative BC, appearance of vertigo, or tinnitus. In our group, we observed no significant relation between insertion depth of the stapes piston, postoperative vertigo, tinnitus, or decrease of the BC.