*ENT Institute, Eye and ENT Hospital of Fudan University †Hearing Medicine Key Laboratory, National Health and Family Planning Commission, Shanghai, China.
Otol Neurotol. 2017 Dec;38(10):1528-1534. doi: 10.1097/MAO.0000000000001600.
To investigate the characteristics of stenotic external auditory canal (EAC) (e.g., shape, length, orientation, and curvature) and to compare them with those of the cholesteatoma and no cholesteatoma groups, which may help to explain cholesteatoma formation to a certain degree.
Computed tomography scans of two groups of patients (with and without EAC cholesteatoma) were analyzed. We determined the degree of microtia, the stenosis of EAC, radius and curvature of osseous EAC bending (abbreviated as OEB-r and OEB-c, respectively), and other anatomic parameters of EAC by using Mimics and Matlab.
There was no significant difference in the degree of microtia between the cholesteatoma and no cholesteatoma groups using the Marx grading system. Additionally, no significant difference was found in the stenosis of EAC between the two groups. The OEB-r was smaller in the cholesteatoma group (4.62 ± 0.62 mm) than in the no cholesteatoma group (7.41 ± 0.50 mm), and the OEB-c was found to be larger in the cholesteatoma group (1.55 ± 0.05 × 10 mm) than in the no cholesteatoma group (1.10 ± 0.10 × 10 mm). Moreover, the OEB-c (OR, 8.60; 95% CI, 2.67-27.75) was associated with EAC cholesteatoma formation.
The curvature of osseous EAC in the cholesteatoma group was significantly larger than that in the no cholesteatoma group. It is suggested that the curvature of osseous EAC was a risk factor for EAC cholesteatoma formation.
研究狭窄外耳道（EAC）的特征（如形状、长度、方向和曲率），并将其与胆脂瘤组和非胆脂瘤组进行比较，这有助于在一定程度上解释胆脂瘤的形成。
对两组患者（有和无 EAC 胆脂瘤）的 CT 扫描进行分析。我们使用 Mimics 和 Matlab 确定小耳畸形的程度、EAC 的狭窄程度、骨 EAC 弯曲半径（简称 OEB-r 和 OEB-c）以及 EAC 的其他解剖参数。
采用 Marx 分级系统，两组胆脂瘤和非胆脂瘤患者的小耳畸形程度无显著差异。两组 EAC 狭窄程度也无显著差异。胆脂瘤组 OEB-r 较小（4.62±0.62mm），而非胆脂瘤组 OEB-r 较大（7.41±0.50mm），胆脂瘤组 OEB-c 较大（1.55±0.05×10mm），而非胆脂瘤组 OEB-c 较小（1.10±0.10×10mm）。此外，OEB-c（OR，8.60；95%CI，2.67-27.75）与 EAC 胆脂瘤形成有关。
胆脂瘤组 EAC 的骨弯曲度明显大于非胆脂瘤组。提示骨 EAC 的曲率是 EAC 胆脂瘤形成的危险因素。
