耳蜗内镜在共同腔畸形人工耳蜗植入的应用

目的 内耳共同腔畸形极重度感音性聋患者在人工耳蜗植入中，使用耳蜗内镜检查腔内畸形状态，了解共同腔畸形的内部形态结构，探讨在耳蜗内镜监视下人工耳蜗植入的手术方法和电极摆放的最佳位置。方法 为5例内耳共同腔畸形患者行人工耳蜗植入手术，在打开共同腔后，使用1mm直径耳蜗内镜深入腔内进行探查．选择电极植入的方向和位置。结果 对5例患者进行共同腔内耳蜗内镜检查．见4例腔内充满液体．吸出后腔壁有扉薄黏膜附着，腔呈不规则圆形，直径平均约为6．5mm，中央区贴近内听道底部位见马蹄形或肾形囊腔．约3mm^3大小，为内耳球囊、椭圆囊和中阶畸形融合的结构；1例腔内淋巴液较少，共同腔壁附着软组织和肉芽，约1．5mm厚，无法将腔壁上的软组织与中阶、球囊、椭圆囊的结构区分。结论 （1）共同腔畸形极重度聋患者不仅前庭、外半规管和耳蜗的骨性结构形态发生了变化，而且腔内耳蜗中阶与前庭的球囊、椭圆囊的膜迷路结构形态也发生了变化；（2）微窥镜下分辨不出基底膜或听神经细胞的形态结构，可见畸形前庭的球囊、椭圆囊的囊性结构；（3）进行共同腔畸形人工耳蜗植入手术时，应在耳蜗内镜的监视下，将电极摆放到准确位置，尽可能贴近共同腔的前壁，不应损伤前庭器官。

Endoscopically guided cochlear implantation in common cavity malformation

Objective In cochlear implantation for common cavity malformation, we inspected the structure in the common cavity with a micro-endoscope, to find the best location for the electrode insertion. Methods Cochlear implantation was performed for 5 profound sensorineural hearing loss patients with common cavity. During the operation, we inspected the structure in the common cavity with a 1 mm micro-endoscope so as to find the best approach and location for the electrode insertion. Results Five cases with common cavity underwent micro-endoscopy during cochlear implantation. In 4 cases, the cavities were full of perilymph. We could find that the cavity was irregularly round-shaped, about 6.5 mm in diameter, with thin mucosa adhere to the cavity wall. In the center area, around the internal acoustic meatus fundus, there was a horseshoe- shaped cystic structure about 3 mm3, which was a combined structure of the saccule, utricle and scala media. In 1 case, there was little perilymph in the cavity, with about 1.5 mm thick soft tissue and granulation adhere to the wall. The saccule, utricle and scala media were not recognizable. Conclusions (1) In common cavity malformation, in addition to the abnormal bony labyrinth such as the cochlea, vestibule and lateral semicircular canal, the inner ear perceptive organ such as the saccule, utricle and scala media were also abnormal. (2) Though we could not identify the basal membrane and sensory epithelia under micro-endoscopy, the utricle and saccule could be clearly identified. (3) During cochlear implantation in common cavity malformation, electrode insertion should be monitored under micro-endoscopy, the electrodes should be put close to the anterior wall of the cavity, otherwise the vestibular organ may be damaged.