Tayebi Meybodi Ali, Borba Moreira Leandro, Zhao Xiaochun, Preul Mark C, Lawton Michael T
Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.
Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.
World Neurosurg. 2019 Jun;126:e463-e472. doi: 10.1016/j.wneu.2019.02.073. Epub 2019 Feb 28.
Rootlets of the lower cranial nerves create a web that limits microsurgical maneuverability in the cerebellomedullary cistern (CMC). The vagoaccessory triangle (VAT) and 2 triangles within it were defined to identify surgical routes to aneurysms of the posterior inferior cerebellar artery (PICA). Dividing the VAT into 2 triangles (suprahypoglossal [SHT] and infrahypoglossal [IHT]), although elegant, oversimplifies CMC anatomy. The triangle formed by the superior and inferior hypoglossal rootlets (hypoglossal-hypoglossal triangle [HHT]) needs consideration as well.
Far-lateral craniotomy was performed on 10 cadaveric heads bilaterally. Areas of CMC triangles were calculated. Relationships between the PICA origin and the adjacent triangles were analyzed. Vertebral artery (VA) exposure and clipping lengths were recorded for each triangle.
The area of SHT was almost twice those of IHT and HHT. The average VA depth relative to VAT increased significantly when moving distally from proximal VA (P < 0.001), but VA exposure and clipping lengths were not significantly different between triangles. IHT, HHT, and SHT defined VA subsegments (V, V, and V), with PICA most commonly originating from V. Based on our cadaveric measurements, the V subsegments were identified with 76% accuracy in angiograms.
Based on this study, VAT should be divided into 3 triangles, not 2. Splayed rootlets of cranial nerve XII and multiple outlet foramina create an important space different from the previously recognized SHT and IHT. These triangles provide corridors to vascular pathologies. V subsegments may be approximated from imaging studies and may help with preoperative planning.
低位颅神经的神经根形成一个网状结构，限制了小脑延髓池（CMC）内的显微手术操作空间。定义了迷走副神经三角（VAT）及其内的两个三角，以确定到达小脑后下动脉（PICA）动脉瘤的手术路径。将VAT分为两个三角（舌下神经上三角[SHT]和舌下神经下三角[IHT]），虽然巧妙，但过于简化了CMC的解剖结构。由舌下神经上下根形成的三角（舌下神经-舌下神经三角[HHT]）也需要考虑。
对10个尸体头部双侧进行远外侧开颅手术。计算CMC三角的面积。分析PICA起源与相邻三角的关系。记录每个三角的椎动脉（VA）暴露长度和夹闭长度。
SHT的面积几乎是IHT和HHT的两倍。从近端VA向远端移动时，相对于VAT的平均VA深度显著增加（P < 0.001），但各三角之间的VA暴露长度和夹闭长度无显著差异。IHT、HHT和SHT界定了VA亚段（V、V和V），PICA最常见起源于V。根据我们的尸体测量，在血管造影中V亚段的识别准确率为76%。
基于本研究，VAT应分为3个三角，而非2个。舌下神经 XII 的散开神经根和多个出孔形成了一个与先前认识的SHT和IHT不同的重要空间。这些三角为血管病变提供了通道。V亚段可通过影像学研究大致确定，有助于术前规划。
