Purcell Derk D, Fischbein Nancy, Lalwani Anil K
Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, USA.
Laryngoscope. 2003 Nov;113(11):1908-11. doi: 10.1097/00005537-200311000-00009.
In patients with congenital sensorineural hearing loss (SNHL), a computed tomography (CT) scan of the temporal bone identifies inner ear malformations in approximately 25%, whereas the inner ear is grossly normal to visual inspection in the remaining 75% of the patients. In the latter group, the hearing loss is often attributed to radiologically undetectable abnormalities of the membranous labyrinth. However, subtle bony malformations may be missed because visual inspection alone is insensitive for detection.
To test the hypothesis that there are subtle bony abnormalities of the inner ear in patients with SNHL who are radiologically deemed to have normal otic bone, using standardized measurements of the inner ear.
Retrospective review.
Measurements of the cochlea, vestibule, and semicircular canals (SCCs) were made on axial and coronal temporal bone CT scans on 15 patients with normal hearing and 15 patients with congenital SNHL and grossly normal temporal bone CT scans. Student's t-test was performed to compare the measurements of the two groups. RESULTS All studies from the SNHL group were deemed normal by visual inspection and standardized measurements (+/-2 SD from normal). Surprisingly, there were significant differences in the measurements of the cochlea and of the SCCs between patients with and without SHNL (P <.05).
As a group, patients with SNHL and a "normal CT scan" have significant differences in the dimensions of the inner ear. This suggests that these patients have disturbed morphogenesis of both membranous and bony labyrinth. This novel observation has important implications for understanding the etiology of SNHL.
在先天性感音神经性听力损失（SNHL）患者中，颞骨计算机断层扫描（CT）可识别出约25%的患者存在内耳畸形，而其余75%的患者内耳在肉眼检查时大致正常。在后一组患者中，听力损失通常归因于膜迷路的放射学不可检测的异常。然而，由于仅靠肉眼检查对检测不敏感，可能会遗漏细微的骨质畸形。
使用内耳的标准化测量方法，检验以下假设：在放射学上被认为耳骨正常的SNHL患者中，内耳存在细微的骨质异常。
回顾性研究。
对15名听力正常的患者和15名先天性SNHL且颞骨CT扫描大致正常的患者，在轴向和冠状位颞骨CT扫描上测量耳蜗、前庭和半规管（SCC）。采用学生t检验比较两组的测量结果。结果：SNHL组的所有研究经肉眼检查和标准化测量（与正常相比±2标准差）均被认为正常。令人惊讶的是，有SNHL和无SNHL的患者在耳蜗和SCC的测量上存在显著差异（P<.05）。
总体而言，SNHL且“CT扫描正常”的患者在内耳尺寸上存在显著差异。这表明这些患者的膜迷路和骨迷路的形态发生均受到干扰。这一新发现对理解SNHL的病因具有重要意义。
