Sabbe A, Verhaert N, Joossen I, Lammens A, Debruyne F
B-ENT. 2015;11(3):183-9.
To analyze changes in bone conduction (BC) thresholds before and after stapedotomy in patients with clinical otosclerosis with a focus on the Carhart notch, which is defined as a significant loss of BC at a certain audiometric frequency.
Retrospective case review of pure tone audiometry (PTA) in 213 patients who underwent a stapedotomy at a tertiary referral center between 2004 and 2011. The patients were grouped by age and the frequency of the Carhart notch. The non-operated ear was also evaluated.
The Carhart notch was present on pre-operative audiometry in 158 (74%) patients at 0.5 (n = 18, 8.45%), 1 (n = 25, 11.70%), or 2 kHz (n = 115, 54.0%). We measured a mean postoperative improvement in BC of 7.5, 8.4, and 8.8 dB HL. Pre-operatively, 55 (25.8%) patients did not exhibit a typical notch configuration. The mean gain in BC, defined on PTA according to the AAO-HNS criteria (0.5, 1, 2 and 3, or 4 kHz), was 1.8 dB HL after stapedotomy.
The Carhart notch was not solely related to the 2 kHz frequency. The greatest gain in BC after stapedotomy for otosclerosis occurred at the notch frequency.
分析临床耳硬化症患者镫骨切除术前后骨导（BC）阈值的变化，重点关注卡哈特切迹，其定义为在特定听力测定频率下骨导显著损失。
对2004年至2011年间在一家三级转诊中心接受镫骨切除术的213例患者的纯音听力测定（PTA）进行回顾性病例分析。患者按年龄和卡哈特切迹频率分组。对未手术耳也进行了评估。
158例（74%）患者术前听力测定存在卡哈特切迹，分别在0.5kHz（n = 18，8.45%）、1kHz（n = 25，11.70%）或2kHz（n = 115，54.0%）。我们测得术后骨导平均改善7.5、8.4和8.8dB HL。术前，55例（25.8%）患者未表现出典型的切迹形态。根据美国耳鼻咽喉头颈外科学会（AAO-HNS）标准（0.5、1、2和3或4kHz）在PTA上定义的骨导平均增益在镫骨切除术后为1.8dB HL。
卡哈特切迹并非仅与2kHz频率相关。耳硬化症患者镫骨切除术后骨导最大增益出现在切迹频率处。
