Department of Clinical Neurosciences, University of Cambridge.
University of Cambridge School of Clinical Medicine.
Otol Neurotol. 2021 Feb 1;42(2):327-334. doi: 10.1097/MAO.0000000000002924.
The goal of this study was to interrogate high-resolution three-dimensional reconstructions of round window anatomy to illustrate and characterize structural variability with implications for atraumatic cochlear implant insertion.
Cochlear implants are increasingly used to improve sound detection in patients with substantial residual hearing. However, traumatic cochlear implant insertion through the round window involving upward deviation of the electrode into the spiral ligament, basilar membrane, and osseous spiral lamina, medial impaction on the modiolus, or interscalar excursion into the scala vestibuli are associated with lower rates of hearing preservation and poorer speech perception.Successful atraumatic insertion is dependent on an anatomical understanding of the middle and inner ear. The round window bony niche lacks distinct demonstrable anatomical landmarks for the position of the round window membrane, and there is limited guidance on the amount of bony overhang that can be safely drilled away. A greater understanding of the anatomical variation around the round window could enhance treatment efficacy.
Fourteen human cadaver temporal bones were imaged using microcomputed tomography. Resulting scans were digitally reconstructed, segmented, and measured.
Round window niche walls vary substantially in size and projection. Round window average short diameter measured 1.30 mm (range 1.07-1.44), and is limited by the crista fenestrae at the inferoanterior margin of the round window. Crista fenestrae size and morphology varied considerably. Reconstructions with solid and translucent panels are presented.
Anatomical heterogeneity should be considered in cochlear implant selection, drilling, and choice of insertion vector.
本研究的目的是通过对圆窗解剖结构的高分辨率三维重建进行研究，以阐明和描述具有非创伤性耳蜗植入插入意义的结构变异性。
耳蜗植入物越来越多地用于改善具有大量残余听力的患者的声音检测。然而，通过圆窗进行创伤性耳蜗植入插入时，电极向上偏离螺旋韧带、基底膜和骨螺旋板、内撞击耳蜗轴突或内嵴进入前庭阶与听力保存率降低和言语感知能力下降有关。成功的非创伤性插入取决于对中耳和内耳的解剖学理解。圆窗骨龛缺乏圆窗膜位置的明显可辨的解剖标志，并且对于可以安全钻除的骨突出量没有多少指导。对圆窗周围解剖结构的更多了解可以提高治疗效果。
使用微计算机断层扫描对 14 个人体尸体颞骨进行成像。对所得扫描进行数字化重建、分割和测量。
圆窗龛壁的大小和突出度差异很大。圆窗平均短直径为 1.30 毫米（范围为 1.07-1.44），由圆窗下前边缘的窗棂限制。窗棂的大小和形态差异很大。提供了带有实心和半透明面板的重建。
在选择耳蜗植入物、钻孔和插入向量时，应考虑解剖学异质性。
