Ryu H, Yamamoto S, Miyamoto T
Department of Neurosurgery, Hamamatsu University School of Medicine, Japan.
Acta Neurochir (Wien). 1998;140(11):1173-6. doi: 10.1007/s007010050233.
Among 155 cases of hemifacial spasm (HFS), the authors found two cases of atypical HFS (1.3%) in which spasm started with the orbicularis oris and buccinator muscles, and gradually spread upward to involve the orbicularis occuli muscle, whereas the reverse process is usually seen in cases of typical HFS. The compression site in cases of atypical HFS is the posterior/rostral aspect of the facial nerve (FN), whereas it was the anterior/caudal aspect of the FN in all cases of typical HFS except for one. The meatal loop of the anterior inferior cerebellar artery (AICA) compressed the FN when the vessel passed between the FN and the eighth cranial nerve (8th N). These findings suggest that the topographical organization in the FN in the cerebellopontine cistern may be reversed to a peripheral distribution: the fibres on the posterior/rostral side of the FN innervate the lower part of the facial muscles, and those in the anterior/caudal side of the nerve innervate the upper part of the facial muscles. When examining patients with HFS, we must very carefully determine whether patients have typical or atypical HFS, to determine whether blood vessels (usually the meatal loop of the AICA) between the FN and the 8th N as well as at the root exit zone of the FN are to be decompressed.
在155例面肌痉挛（HFS）患者中，作者发现2例非典型HFS（1.3%），其痉挛始于口轮匝肌和颊肌，然后逐渐向上蔓延至眼轮匝肌，而典型HFS病例通常是相反的过程。非典型HFS病例的压迫部位是面神经（FN）的后部/嘴侧，而除1例典型HFS病例外，其余典型HFS病例的压迫部位均为FN的前部/尾侧。当小脑下前动脉（AICA）的脑桥小脑角段在FN和第八颅神经（第8神经）之间通过时，会压迫FN。这些发现表明，脑桥小脑角池内FN的拓扑结构可能颠倒为外周分布：FN后部/嘴侧的纤维支配面部肌肉的下部，而神经前部/尾侧的纤维支配面部肌肉的上部。在检查HFS患者时，我们必须非常仔细地确定患者是典型还是非典型HFS，以确定是否要对面神经和第8神经之间以及FN根出区的血管（通常是AICA的脑桥小脑角段）进行减压。
