目的  探讨术前颞骨高分辨率CT（HRCT）评估人工耳蜗植入术（CI）中圆窗膜暴露的程度，为感音神经性耳聋患者行CI手术入径提供参考。 方法  对89例在解放军第九六○医院行CI手术患者的术前HRCT和术中圆窗膜暴露程度进行回顾性分析。根据St. Thomas’ Hospital（STH）分类标准，分为63例Ⅰ型、17例 Ⅱa型和 9例 Ⅱb+Ⅲ型。于术前颞骨HRCT轴位圆窗龛层面测量面神经垂直段前缘与外耳道后壁后缘的垂直距离（面-壁距），面神经垂直段前缘与圆窗膜中点的距离（面-膜距）及面神经垂直段前缘与耳蜗底周的垂直距离（面神经点的位置），分析各参数在不同年龄、不同分型之间有无差异；经面神经垂直段前缘作一平行于外耳道后壁的延长线，评估其与圆窗的位置关系对圆窗膜暴露的影响；术前预测与术中实际的电极植入方式进行比较。 结果  面神经垂直段前缘与耳蜗底周的垂直距离差异有统计学意义（P<0.05）；面神经垂直段前缘且平行于外耳道后壁的延长线与圆窗的位置关系对圆窗膜的暴露差异有统计学差异（P<0.05）；术前预测与术中实际的电极植入入径差异无统计学意义（P>0.05）。 结论  在术前颞骨HRCT上，面神经垂直段前缘与耳蜗底周的垂直距离及经面神经垂直段前缘且平行于外耳道的延长线与圆窗的位置关系可以预测术中圆窗膜暴露的难易，为CI电极植入入径提供参考。

Objective  To correlate preoperative high resolution computed tomography (HRCT) findings of the temporal bone with the degree of round window membrane (RWM) exposure observed during cochlear implant  surgery, and to establish an imaging-based predictive model to guide surgical approach selection in patients with sensorineural hearing loss.   Methods  A retrospective analysis was performed on 89 patients who underwent cochlear implantation at the People’s  Liberation Army 960th Hospital. Preoperative temporal bone high-resolution computed tomography (HRCT) scans were used to analyze and correlate with the intraoperative degree of RWM exposure. Based on the St. Thomas’ Hospital (STH) classification system, the cohort distribution was as follows, type Ⅰ (n=63), type Ⅱa (n=17), and type Ⅱb+Ⅲ (n=9). On the axial HRCT slice at the level of the round window niche, the following parameters were measured, including facial nerve to bony wall distance, the vertical distance from the anterior edge of the facial nerve’s vertical segment to the posterior edge of the external auditory canal’s bony wall; Facial nerve to membrane distance, the distance from the anterior edge of the facial nerve’s vertical segment to the midpoint of the RWM; Facial nerve point position, the vertical distance from the anterior edge of the facial nerve’s vertical segment to the basal turn of the cochlea. The measured parameters were analyzed for differences across age groups and STH classification types. An extension line from the anterior border of the vertical segment of the facial nerve, parallel to the external auditory canal was drawn, and the influence of its positional relationship on RWM. Finally, the preoperative predictions for the electrode insertion approach were compared with the actual surgical method  employed.  Results  A statistically significant difference was observed in the vertical distance between the anterior edge of the facial nerve’s vertical segment and the basal turn of the cochlea (P<0.05).The positional relationship between the round window and an extension line drawn anterior to the vertical segment of the facial nerve and parallel to the posterior wall of the external auditory canal had a statistically significant impact on round window membrane exposure (P<0.05). No statistically significant difference was found between the preoperatively predicted and the intraoperatively actual electrode insertion approaches (P>0.05).   Conclusion  Preoperative temporal bone HRCT measurements, specifically the vertical distance from the facial nerve to the cochlear basal turn and the positional relationship of a defined facial nerve extension line to the round window, can predict the difficulty of intraoperative RWM exposure, offering significant clinical utility for pre-surgical planning of the electrode insertion approach in cochlear implantation.