Carhart Notch 2-kHz Bone Conduction Threshold Dip A Nondefinitive Predictor of Stapes Fixation in Conductive Hearing Loss With Normal Tympanic Membrane
Carhart Notch 2-kHz Bone Conduction Threshold Dip A Nondefinitive Predictor of Stapes Fixation in Conductive Hearing Loss With Normal Tympanic Membrane
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DOI：
10.1001/archoto.2011.14
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发表时间：
2011-03-01
影响因子：
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通讯作者：
Yamasoba, Tatsuya
中科院分区：
文献类型：
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作者：
Kashio, Akinori;Ito, Ken;Yamasoba, Tatsuya
目的：通过比较Carhart切迹（2khz骨传导阈值倾角[2KBD]）在各种听骨链异常耳中的发生率，评价其在镫骨固定诊断中的意义。设计：回顾性研究。单位：大学医院。患者：连续127例先天性听骨异常或耳硬化症患者共153耳。主要结果测量：2KBD深度定义为2 kHz阈值减去1和4 kHz阈值的平均值。在镫骨固定组（包括耳硬化和先天性镫骨固定）、镫骨关节脱离组、镫骨或砧骨固定组中评估2KBD（深度，>= 10 dB）、2KBD深度、2KBD深度与气骨间隙的关系以及术后2khz骨传导恢复情况。结果：102只镫骨固定耳中32只（31.4%），19只镫骨关节脱离耳中5只（26.3%），20只内踝或砧骨固定耳中6只（30.0%）（12只有其他诊断）存在2KBD。镫骨固定组平均（SD） 2KBD深度为17.3 (5.2)dB，包括镫骨关节脱离组为18.5 (2.2)dB，踝或砧骨固定组为16.3 (2.1)dB。三组间差异无统计学意义。2KBD深度与气骨间隙程度无相关性。镫骨固定组2 khz骨传导阈值恢复低于其他2组。结论：2KBD在镫骨固定组、包括镫骨关节脱离组、踝或砧骨固定组的发生率相似，提示2KBD不是镫骨固定的有效预测指标。
Objective: To evaluate the significance of the Carhart notch (a 2-kHz bone conduction threshold dip [2KBD] in the diagnosis of stapes fixation by comparing its incidence among ears with various ossicular chain abnormalities.Design: Retrospective study.Setting: University hospital.Patients: A total of 153 ears among 127 consecutive patients with a congenital ossicular anomaly or otosclerosis.Main Outcome Measures: The 2KBD depth was defined as the threshold at 2 kHz minus the mean of thresholds at 1 and 4 kHz. The presence of 2KBD (depth, >= 10 dB), 2KBD depth, relationship between 2KBD depth and air-bone gap, and 2-kHz bone conduction recovery after operation were evaluated in a stapes fixation group (which included cases of otosclerosis and congenital stapes fixation), an incudostapedial joint detachment group, and a malleus or incus fixation group.Results: A 2KBD was present in 32 of 102 stapes fixation ears (31.4%), 5 of 19 incudostapedial joint detachment ears (26.3%), and 6 of 20 malleus or incus fixation ears (30.0%) (12 ears had other diagnoses). The mean (SD) 2KBD depths were 17.3 (5.2) dB in the stapes fixation group, 18.5 (2.2) dB in the incudostapedial joint detachment group, and 16.3 (2.1) dB in the malleus or incus fixation group. No statistically significant differences were noted among these 3 groups. No correlation was noted between 2KBD depth and air-bone gap extent. Recovery of 2-kHz bone conduction threshold in the stapes fixation group was less than that in the other 2 groups.Conclusion: Incidence of 2KBD was similar among the stapes fixation, incudostapedial joint detachment, and malleus or incus fixation groups, implying that 2KBD is not a useful predictor of stapes fixation.