Abstract：
OBJECTIVE: The retrolabyrinthine (presigmoid) approach has been utilized in various skull base surgeries but has not been fully utilized in the management of internal auditory canal (IAC) lesions, such as vestibular schwannoma (VS). Microsurgical retrolabyrinthine approach provides limited visualization of the IAC, while endoscopic-assisted techniques allow for further lateral exposure with labyrinthine preservation.
BACKGROUND: Traditional approaches to the IAC have the disadvantage of hearing sacrifice or retraction of brain tissue. With the introduction of endoscopic techniques and enhanced visualization, access to this region of complex anatomy is possible.
METHODS: Radiomorphometric and anatomical dissection was performed on two cadaveric temporal bones. High-resolution computed tomography was used to segment and delineate the volume of the IAC. Projected accessible IAC was compared to actual postdissection data with preservation of the posterior semicircular canal (PSCC) via the retrolabyrinthine corridor.
RESULTS: While preserving the PSCC, the 0° and 30° endoscopes visualized 57.1% and 78.6% of the IAC for cadaver 1, and 64.0% and 76.0% of the IAC for cadaver 2, respectively. Sacrificing the PSCC, the 0° and 30° endoscopes provided visualization of 78.6% 85.7% of the IAC for cadaver 1, and 88.0% and 95.1% of the IAC for cadaver 2, respectively.
CONCLUSIONS: Retrolabyrinthine approach to resection of VS is a potentially viable hearing-preserving alternative to traditional approaches. This approach provides access to the majority of the IAC, while angled endoscopes or sacrifice of the PSCC can provide additional access toward the fundus. Further studies are needed to determine the clinical feasibility of this approach.
BACKGROUND: Traditional approaches to the IAC have the disadvantage of hearing sacrifice or retraction of brain tissue. With the introduction of endoscopic techniques and enhanced visualization, access to this region of complex anatomy is possible.
METHODS: Radiomorphometric and anatomical dissection was performed on two cadaveric temporal bones. High-resolution computed tomography was used to segment and delineate the volume of the IAC. Projected accessible IAC was compared to actual postdissection data with preservation of the posterior semicircular canal (PSCC) via the retrolabyrinthine corridor.
RESULTS: While preserving the PSCC, the 0° and 30° endoscopes visualized 57.1% and 78.6% of the IAC for cadaver 1, and 64.0% and 76.0% of the IAC for cadaver 2, respectively. Sacrificing the PSCC, the 0° and 30° endoscopes provided visualization of 78.6% 85.7% of the IAC for cadaver 1, and 88.0% and 95.1% of the IAC for cadaver 2, respectively.
CONCLUSIONS: Retrolabyrinthine approach to resection of VS is a potentially viable hearing-preserving alternative to traditional approaches. This approach provides access to the majority of the IAC, while angled endoscopes or sacrifice of the PSCC can provide additional access toward the fundus. Further studies are needed to determine the clinical feasibility of this approach.
摘要：
目的：在各种颅底手术中都采用了后迷路（乙状）入路，但在处理内听道（IAC）病变方面尚未得到充分利用。如前庭神经鞘瘤（VS）。显微手术后迷路入路对IAC的可视化有限，而内窥镜辅助技术允许进一步的横向暴露与迷宫保存。
背景：IAC的传统方法具有听力牺牲或脑组织缩回的缺点。随着内窥镜技术的引入和增强的可视化，进入这个区域的复杂的解剖是可能的。
方法：对两个尸体颞骨进行放射形态测量和解剖解剖。高分辨率计算机断层扫描用于分割和描绘IAC的体积。将预测的可访问IAC与实际的解剖后数据进行比较，并通过后迷宫走廊保留了后半规管（PSCC）。
结果：在保留PSCC的同时，0°和30°内窥镜分别显示了尸体1的IAC的57.1％和78.6％，尸体2的IAC的64.0％和76.0％。牺牲PSCC，0°和30°内窥镜分别为尸体1提供了78.6%85.7%的IAC可视化,为尸体2提供了88.0%和95.1%的IAC可视化。
结论：后迷路入路切除VS是传统方法的潜在可行的听力保留替代方法。这种方法提供了对大多数IAC的访问，而倾斜的内窥镜或PSCC的牺牲可以提供朝向眼底的额外通道。需要进一步的研究来确定这种方法的临床可行性。
背景：IAC的传统方法具有听力牺牲或脑组织缩回的缺点。随着内窥镜技术的引入和增强的可视化，进入这个区域的复杂的解剖是可能的。
方法：对两个尸体颞骨进行放射形态测量和解剖解剖。高分辨率计算机断层扫描用于分割和描绘IAC的体积。将预测的可访问IAC与实际的解剖后数据进行比较，并通过后迷宫走廊保留了后半规管（PSCC）。
结果：在保留PSCC的同时，0°和30°内窥镜分别显示了尸体1的IAC的57.1％和78.6％，尸体2的IAC的64.0％和76.0％。牺牲PSCC，0°和30°内窥镜分别为尸体1提供了78.6%85.7%的IAC可视化,为尸体2提供了88.0%和95.1%的IAC可视化。
结论：后迷路入路切除VS是传统方法的潜在可行的听力保留替代方法。这种方法提供了对大多数IAC的访问，而倾斜的内窥镜或PSCC的牺牲可以提供朝向眼底的额外通道。需要进一步的研究来确定这种方法的临床可行性。
