Wideband acoustic immittance measurements in assessing crimping status following stapedotomy: A temporal bone study.

OBJECTIVE: To ascertain if wideband acoustic immitance (WAI) measurements are useful in assessing crimping status following stapedotomy.

DESIGN: WAI measurements were obtained using the Mimosa Acoustics HearID system. Wideband chirp sound stimuli and a set of tone stimuli for nine frequencies between 0.2 and 6 kHz were used at 60 dB SPL. Five sets of measurements were performed on each temporal bone: mobile stapes, stapes fixation and stapedotomy followed by insertion of a tightly crimped, a loosely crimped and an uncrimped prosthesis.

STUDY SAMPLE: Eight fresh-frozen temporal bones were harvested from human cadaveric donors.

RESULTS: At lower frequencies, up to 1 kHz, stapes fixation decreased absorbance. Compared to the baseline absorbance, absorbance with stapes fixation dropped by 6 to 17% in absolute terms from the baseline value (p = 0.027). Absorbance was not affected in higher frequencies (p = 0.725). Stapedotomy changed the absorbance curve significantly compared to the normal condition with an increase of absolute absorbance values by 6 to 36% around 0.25-1 kHz (p-value <0.01). The crimping conditions did not differ from one another (p = 0.555).

CONCLUSION: WAI is not useful in distinguishing between tightly crimped, loosely crimped and uncrimped stapes prostheses following stapedotomy.