Acoustic role of the buttress and posterior incudal ligament in human temporal bones

OBJECTIVES: In middle ear surgery using intact ear canal wail techniques, t he buttress, which is the bony bridge at the medial end of the posterior-su perior bony ear canal, is commonly retained during posterior tympanotomy, I n some cases, the surgical exposure may be improved by resectioning the but tress, and this requires sectioning the posterior incudal ligament, To date , the acoustic effects of removing the buttress with sectioning of the atta ched ligament have not been studied, METHOD: Using a laser Doppler vibrometer system, 15 human cadaver temporal bones were measured with 80 dB sound pressure level at the tympanic membran e over the 0.1 to 10 kHz frequency range. RESULT: The resection of the buttress and sectioning the posterior incudal ligament had no effect on stapes footplate velocity. CONCLUSION: These results suggest that the posterior incudal ligament does not play a significant role in the acoustic function of the ossicles.