Department of Surgery (Otolaryngology), University of Melbourne, Level 5, Royal Victorian Eye and Ear Hospital, 32, Gisborne Street, East Melbourne, VIC, 3002, Australia.
Eur Arch Otorhinolaryngol. 2022 Jan;279(1):137-147. doi: 10.1007/s00405-021-06633-8. Epub 2021 Feb 5.
To provide practical guidance to the operative surgeon by mapping the location, where acceptable straight-line virtual cochlear implant electrode trajectories intersect the facial recess. In addition, to investigate the influence of facial recess preparation, virtual electrode width and surgical approach to the cochlea on these available trajectories.
The study was performed on imaging data from eight cadaveric temporal bones within the University of Melbourne Virtual Reality (VR) Temporal Bone Surgery Simulator. The facial recess was opened to varying degrees, and acceptable trajectory vectors with varying diameters were calculated for electrode insertions via cochleostomy or round window membrane (RWM). The percentage of acceptable insertion vectors through each location of the facial recess was visually represented using heatmaps.
Seven of the eight bones allowed for acceptable vector trajectories via both cochleostomy and RWM approaches. These acceptable trajectories were more likely to lie superiorly within the facial recess for insertion via the round window, and inferiorly for insertion via cochleostomy. Cochleostomy insertions required a greater degree of preparation and skeletonisation of the junction of the facial nerve and chorda tympani within the facial recess. The width of the virtual electrode had only marginal impact on the availability of acceptable trajectories. Heatmaps emphasised the intimate relationship the acceptable trajectories have with the facial nerve and chorda tympani.
These findings highlight the differences in the acceptable straight-line trajectories for electrodes when implanted via the round window or cochleostomy. There were notable exceptions to both surgical approaches, likely explained by the variation of hook region anatomy. The methodology used in this study holds promise for translation to patient specific surgical planning.
通过绘制可接受的直线虚拟耳蜗植入电极轨迹与面隐窝相交的位置，为手术医生提供实用的指导。此外，还研究了面隐窝准备、虚拟电极宽度以及对耳蜗的手术入路对面神经和鼓索神经这些可利用轨迹的影响。
该研究在墨尔本大学虚拟现实（VR）颞骨手术模拟器的 8 个尸体颞骨的影像学数据上进行。对面隐窝进行不同程度的开放，并计算了通过圆窗或圆窗膜（RWM）进行电极插入的不同直径的可接受轨迹向量。通过热图直观地表示了面隐窝各个部位可接受插入向量的百分比。
在 8 个颞骨中，有 7 个允许通过圆窗和 RWM 两种方法进行可接受的轨迹向量。这些可接受的轨迹通过圆窗更有可能位于面隐窝的上部，而通过耳蜗造口术则位于下部。耳蜗造口术需要对面神经和面神经鼓索在面隐窝内的交界处进行更大程度的准备和骨骼化。虚拟电极的宽度仅对面神经和鼓索的可接受轨迹的可用性产生微小影响。热图强调了可接受轨迹与面神经和鼓索之间的密切关系。
这些发现强调了通过圆窗或耳蜗造口术植入电极时可接受的直线轨迹的差异。这两种手术方法都有明显的例外，可能是由于钩区解剖结构的变化所致。本研究中使用的方法有望转化为患者特异性手术规划。
