Colasanti Roberto, Tailor Al-Rahim Abbasali, Zhang Jun, Ammirati Mario
Dardinger Microneurosurgical Skull Base Laboratory, Department of Neurological Surgery, Wexner Medical Center, The Ohio State University, N1025 Doan Hall, 410 West 10th Avenue, Columbus, OH, 43210, USA.
Neurosurg Rev. 2015 Oct;38(4):715-21. doi: 10.1007/s10143-015-0634-2. Epub 2015 Apr 25.
The endolymphatic sac (ES) and the vestibular aqueduct (VA) are often in the surgical field when posterior fossa lesions are targeted using retrosigmoid approaches. The purpose of this work is to validate neuronavigator accuracy in predicting VA location as well as to give guidelines to preserve the ES and VA. A retrosigmoid approach was performed bilaterally in six specimens in the semisitting position. Preoperatively, we registered in the CT scans the position of the VA genu (virtual genu). After the approach execution, ES and VA genu topographic relationships with evident posterolateral cranial base structures were measured using neuronavigation. Next, we exposed the VA genu: its position coincided with the virtual VA genu in all the specimens. On the average, the ES was 17.93 mm posterosuperolateral to the XI nerve in the jugular foramen, 12.26 mm posterolateral to the internal acoustic meatus, 20.13 mm anteromedial to the petro-sigmoid intersection at a point 13.30 mm inferior to the petrous ridge. The VA genu was located 7.23 mm posterolateral to the internal acoustic meatus, 18.11 mm superolateral to the XI nerve in the jugular foramen, 10.27 mm inferior to the petrous ridge, and 6.28 mm anterolateral to the endolymphatic ledge at a depth of 3.46 mm from the posterior pyramidal wall. Our study demonstrates that is possible to use neuronavigation to reliably predict the location of the VA genu. In addition, neuronavigation may be effectively used to create a topographical framework that may help maintaining the integrity of the ES/VA during retrosigmoid approaches.
当采用乙状窦后入路靶向处理后颅窝病变时，内淋巴囊（ES）和前庭导水管（VA）常常处于手术视野内。本研究的目的是验证神经导航在预测VA位置方面的准确性，并给出保留ES和VA的指导原则。对6个标本采用半坐位双侧乙状窦后入路。术前，我们在CT扫描中标记了VA膝部（虚拟膝部）的位置。在完成手术入路后，使用神经导航测量ES和VA膝部与明显的颅后外侧基底结构之间的地形关系。接下来，我们暴露VA膝部：其位置在所有标本中均与虚拟VA膝部相符。平均而言，ES位于颈静脉孔内XI神经后上外侧17.93mm处、内耳道后外侧12.26mm处、岩骨嵴下方13.30mm处的岩骨 - 乙状窦交点前内侧20.13mm处。VA膝部位于内耳道后外侧7.23mm处、颈静脉孔内XI神经上外侧18.11mm处、岩骨嵴下方10.27mm处以及距后锥壁深度3.46mm处的内淋巴嵴前外侧6.28mm处。我们的研究表明，使用神经导航能够可靠地预测VA膝部的位置。此外，神经导航可有效地用于创建一个地形框架，这可能有助于在乙状窦后入路过程中保持ES/VA的完整性。
