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.