Department of Otolaryngology, Jagiellonian University Medical College in Kraków, Krakow, Poland.
Ear Nose Throat J. 2024 Apr;103(4):241-247. doi: 10.1177/01455613211043685. Epub 2021 Oct 11.
The presence of Carhart's notch at 2000 Hz in otosclerosis links the changed bone conduction for this frequency with the otosclerotic process occurring in the oval window. The aim of this study is to perform an audiometric assessment of the effectiveness of surgical treatment of otosclerosis depending on the incidence of Carhart's notch. The analysis included 116 patients treated surgically for the first time due to otosclerosis. Patients were divided into 4 groups depending on the occurrence of Carhart's notch, determined by pure-tone audiometry (PTA) before the surgery and 36 months afterward. The mean value of bone conduction thresholds was calculated for 500 Hz, 1000 Hz, 2000 Hz, and 3000 Hz in the groups in which the Cahart's notch was observed. This value of bone conduction (BC) was a reference point for further analysis in patients who had no preoperative or postoperative Carhart's notch. The analysis indicated that Cahart's notch in preoperative PTA is a statistically significant improvement factor for average BC. It was found that over a longer observation period, the presence of Carhart's notch has adverse effects on the size of the postoperative air-bone gap, and consequently on hearing improvement after surgical treatment. A comparison between patients from the two groups without preoperative Carhart's notch found that no beneficial effects of the surgery on speech comprehension were observed regarding high-level sensorineural hearing loss (SNHL). (1) In a long-term observation post-stapedotomy, average BC values were found to improve. Nevertheless, the improvement is less evident in patients with preoperative Carhart's notch. (2) Disappearance of Cahart's notch after surgical treatment of otosclerosis is a good prognosis of improvement in speech audiometry. (3) Deep SNHL in the absence of Carhart's notch in PTA constitutes a bad prognostic factor for improvement in speech audiometry in patients qualified for surgical treatment of otosclerosis.
在耳硬化症中，2000Hz 时存在 Carhart 切迹，这将该频率的骨导变化与发生在卵圆窗的耳硬化症过程联系起来。本研究的目的是通过评估 Carhart 切迹的发生率来对耳硬化症的手术治疗效果进行听力评估。该分析包括 116 名因耳硬化症首次接受手术治疗的患者。根据术前和术后 36 个月纯音测听（PTA）确定的 Carhart 切迹的发生情况，将患者分为 4 组。对于观察到 Carhart 切迹的组，计算了 500Hz、1000Hz、2000Hz 和 3000Hz 处骨导阈值的平均值。对于术前或术后均无 Carhart 切迹的患者，将该骨导值（BC）作为进一步分析的参考点。分析表明，术前 PTA 中的 Carhart 切迹是平均 BC 的统计学显著改善因素。结果发现，在较长的观察期内，Carhart 切迹的存在对术后气骨导间隙的大小以及手术治疗后的听力改善有不利影响。对术前无 Carhart 切迹的两组患者进行比较发现，对于高水平感音神经性听力损失（SNHL），手术对言语理解没有有益的影响。（1）在长期观察镫骨手术后，发现平均 BC 值有所提高。然而，术前有 Carhart 切迹的患者改善不明显。（2）耳硬化症手术后 Carhart 切迹的消失是言语测听改善的良好预后。（3）PTA 中无 Carhart 切迹且存在深度 SNHL 构成了适合手术治疗耳硬化症的患者言语测听改善的不良预后因素。
