Meybodi Ali Tayebi, Liang Allison S, Mokhtari Pooneh, Moreira Leandro Borba, Zhao Xiaochun, Lawton Michael T, Preul Mark C
Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona.
Department of Neurosurgery, Rutgers New Jersey Medical School, Newark, New Jersey, United States.
Surg Neurol Int. 2023 Feb 3;14:37. doi: 10.25259/SNI_1097_2022. eCollection 2023.
The nervus intermedius (NI) comprises fibers originating from the trigeminal, superior salivary, and solitary tract nuclei, which join the facial nerve (cranial nerve [CN] VII). Neighboring structures include the vestibulocochlear nerve (CN VIII), the anterior inferior cerebellar artery (AICA), and its branches. Microsurgical procedures at the cerebellopontine angle (CPA) benefit from understanding NI anatomy and relationships, especially for the microsurgical treatment of geniculate neuralgia, where the NI is transected. This study sought to characterize common relationships between the NI rootlets, CN VII, CN VIII, and the meatal loop of AICA at the internal auditory canal (IAC).
Seventeen cadaveric heads underwent retrosigmoid craniectomy. Following complete unroofing of the IAC, the NI rootlets were individually exposed to identify their origins and insertion points. The AICA and its meatal loop were traced to assess their relationship with the NI rootlets.
Thirty-three NIs were identified. The median number of NI rootlets was 4 per NI (interquartile range, 3-5). The rootlets mainly originated from the proximal premeatal segment of CN VIII (81 of 141, 57%) and inserted onto CN VII at the IAC fundus (89 of 141, 63%). When crossing the acoustic-facial bundle, the AICA most frequently passed between the NI and CN VIII (14 of 33, 42%). Five composite patterns of neurovascular relationships were identified regarding NI.
Although certain anatomical trends can be identified, the NI has a variable relationship with the adjacent neurovascular complex at the IAC. Therefore, anatomical relationships should not be used as the sole method of NI identification during CPA surgery.
中间神经（NI）由起源于三叉神经核、上涎核和孤束核的纤维组成，这些纤维与面神经（颅神经[CN]VII）相连。其相邻结构包括前庭蜗神经（CN VIII）、小脑前下动脉（AICA）及其分支。了解NI的解剖结构和关系有助于桥小脑角（CPA）的显微手术，特别是在切断NI的膝状神经节神经痛的显微手术治疗中。本研究旨在描述NI小根、CN VII、CN VIII和内耳道（IAC）处AICA的肉 loop之间的常见关系。
对17个尸体头部进行乙状窦后开颅术。在完全打开IAC后，分别暴露NI小根以确定其起源和插入点。追踪AICA及其肉 loop以评估它们与NI小根的关系。
共识别出33条NI。每条NI的小根中位数为4条（四分位间距，3 - 5条）。小根主要起源于CN VIII的近侧肉前段（141条中的81条，57%），并在IAC底部插入CN VII（141条中的89条，63%）。当AICA穿过听面束时，最常从NI和CN VIII之间穿过（33条中的14条，42%）。关于NI，确定了五种神经血管关系的复合模式。
虽然可以识别出某些解剖学趋势，但NI与IAC处相邻神经血管复合体的关系存在变异。因此，在CPA手术中，解剖关系不应作为识别NI的唯一方法。
