Department of Neurosurgery, Lenox Hill Hospital, New York, New York, USA.
Department of Neurosurgery, Lenox Hill Hospital, New York, New York, USA.
World Neurosurg. 2020 May;137:179-182. doi: 10.1016/j.wneu.2020.01.196. Epub 2020 Feb 4.
Hemifacial spasm (HFS) is a neuromuscular disorder resulting from cranial nerve VII compression at the root entry zone, characterized by brief, involuntary, progressive spasms of muscles on one side of face. The cisternal part of cranial nerve VII myelinated by Schwann cells is considered relatively resistant to compression. Rarely, direct compression over this segment without coexistent root entry zone compression may also result in HFS. An aberrant vessel posterior inferior cerebellar artery/anterior inferior cerebellar artery loop remains the leading cause of compression at this location. Cerebellopontine angle tumors or cysts may affect cranial nerve VII distally. However, bony meatal stenosis with pure distal facial nerve compression leading to HFS in the absence of other clinical symptoms has not been reported.
A 53-year-old woman presented with worsening left HFS for 9 years despite multiple trials of medical therapy, which severely impeded her social life and occupation. Temporal bone computed tomography revealed severe stenosis of the left internal auditory meatus (2.36 mm) compared with the right side (4.67 mm). Under three-dimensional exoscope guidance, a left retrosigmoid suboccipital craniotomy was performed, the posterior bony wall of the internal auditory canal was drilled to decompress the canal, and durotomy was performed to release the contents. Her symptoms resolved without developing facial weakness or hearing deficits.
An aberrant anterior inferior cerebellar artery vascular loop is usually the most frequent lesion causing compression of the distal cisternal part of the facial nerve. However, other purely distal or coexistent lesions must be actively sought for both in preoperative radiologic images and during surgery.
面肌痉挛（HFS）是一种由颅神经 VII 在神经根入口区受压引起的神经肌肉疾病，其特征是面部一侧肌肉短暂、无意识、进行性痉挛。由施旺细胞髓鞘化的颅神经 VII 的脑池段被认为相对耐受压迫。很少有情况下，即使没有神经根入口区受压，该节段的直接压迫也可能导致 HFS。小脑后下动脉/小脑前下动脉异常血管环仍然是该部位压迫的主要原因。桥小脑角肿瘤或囊肿可能会影响颅神经 VII 的远端。然而，骨性前庭导水管狭窄伴单纯面神经远端受压导致 HFS 而无其他临床症状尚未见报道。
一名 53 岁女性，左侧面肌痉挛 9 年，尽管多次尝试药物治疗，但病情仍逐渐加重，严重影响其社交生活和职业。颞骨 CT 显示左侧内听道严重狭窄（2.36mm），右侧内听道（4.67mm）。在三维手术显微镜引导下，行左侧乙状窦后枕下入路，磨除内听道后骨壁以减压，行硬脑膜切开以释放内容物。患者症状缓解，无面瘫或听力下降。
小脑前下动脉异常血管环通常是导致面神经远端脑池段受压的最常见病变。然而，无论是术前影像学检查还是术中，都必须积极寻找其他单纯远端病变或共存病变。
