Yehezkely Michal Kaufmann, Grinblat Golda, Dor Miriam Geal, Chordekar Shai, Perez Ronen, Adelman Cahtia, Sohmer Haim
Department of Otorhinolaryngology, Head and Neck Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Department of Otology and Skull Base Surgery, Gruppo Otologico, Piacenza, Rome, Italy.
J Int Adv Otol. 2019 Apr;15(1):8-11. doi: 10.5152/iao.2019.6268.
To assess bone conduction (BC) thresholds following radical mastoidectomy and subtotal petrosectomy, in which the tympanic membrane and the ossicular chain, responsible for osseous BC mechanisms, are surgically removed. The removal of the tympanic membrane and the ossicular chain would reduce the contributions to BC threshold of the following four osseous BC mechanisms: the occlusion effect of the external ear, middle ear ossicular chain inertia, inner ear fluid inertia, and distortion (compression-expansion) of the walls of the inner ear.
BC thresholds were determined in 64 patients who underwent radical mastoidectomy and in 248 patients who underwent subtotal petrosectomy.
BC thresholds were normal (≤15 dB HL, i.e., better) in 19 (30%) radical mastoidectomy patients and in 19 (8%) subtotal petrosectomy patients at each of the frequencies assessed (0.5, 1.0, 2.0, and 4.0 kHz).
Normal BC thresholds seen in many patients following mastoidectomy and petrosectomy may be induced by a non-osseous mechanism, and the onset ("threshold") of the classical osseous BC mechanisms may be somewhat higher.
评估在根治性乳突切除术和部分岩骨切除术之后的骨传导（BC）阈值，在这些手术中，负责骨传导机制的鼓膜和听骨链会被手术切除。鼓膜和听骨链的切除会减少以下四种骨传导机制对BC阈值的贡献：外耳道的封闭效应、中耳听骨链惯性、内耳液体惯性以及内耳壁的畸变（压缩-扩张）。
对64例行根治性乳突切除术的患者和248例行部分岩骨切除术的患者测定BC阈值。
在每个评估频率（0.5、1.0、2.0和4.0kHz）下，19例（30%）根治性乳突切除术患者和19例（8%）部分岩骨切除术患者的BC阈值正常（≤15dB HL，即更好）。
乳突切除术和岩骨切除术后许多患者出现的正常BC阈值可能由非骨传导机制引起，并且经典骨传导机制的起始（“阈值”）可能略高。
