Klinik für Neurochirurgie, Universitäts-Spital Zürich, Zürich, Switzerland.
Neurosurgery. 2011 Mar;68(1 Suppl Operative):23-31; discussion 31. doi: 10.1227/NEU.0b013e31820781fb.
Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage.
To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa.
Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient.
Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm).
Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.
通过第四脑室底部暴露内在脑干病变需要精确识别面神经（CN VII）纤维以避免损伤。
评估在菱形窝表面可以电刺激面神经的区域的形状、大小和可变性。
在 18 个月的时间内，对 20 名患有各种脑干和/或小脑病变的患者进行了手术。刺激面神经纤维以在靶肌肉中产生复合肌肉动作电位（CMAP）。使用 CMAP 产生的部位，为每位患者构建了菱形窝的详细功能图。
切除的病变包括 14 个胶质瘤、5 个海绵状血管瘤和 1 个表皮样囊肿。在映射的 40 个响应区域中，有 19 个到达了中央沟。从 obex 到反应区的尾侧边界的距离范围为 8 至 27 毫米（中位数，17 毫米）。反应区的前后长度范围为 2 至 15 毫米（中位数，5 毫米）。
即使在面神经丘和下面的病理病变之间有明显距离的患者中，面神经反应区的大小和位置也表现出很大的可变性。靠近面神经丘的病变明显扭曲了反应区。这是首次记录菱形窝中 CN VII 反应区的可变性。对这种显著可变性的认识可能有助于评估进入脑干的安全进入区，并有助于改善在大脑这一敏感区域进行神经外科干预后的结果。
