Effect of absence of malleus on ossiculoplasty in human temporal bones

OBJECTIVE: We evaluated the effect of malleus presence or absence on middle ear sound transmission after middle ear reconstruction in a temporal bone model. STUDY DESIGN: Human cadaveric temporal bone study. METHODS: The velocity of the stapes footplate was measured using a laser Doppler vibrometer. After baseline measurements in eight intact temporal bones, reconstructed middle ear transmission with and without the malleus was analyzed. Furthermore, to assess the influence of interposed cartilage, cartilage pieces of three different diameters were inserted and the three test conditions compared. RESULTS: Reconstruction without a malleus tended to be slightly worse at 0.6 to 3.0 kHz. However, these differences were not statistically significant. In the cartilage experiments, the large-diameter cartilage was the worst at 0.25 kHz and 0.5 kHz but was better than the medium-diameter cartilages at 3.0 kHz and 4.0 kHz (P < 0.05). CONCLUSION: Absence of the malleus impaired middle ear sound transmission slightly in the mid frequencies compared to reconstruction with the malleus present; the differences were not statistically significant. (C) 2008 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.