Ito Masato, Higuchi Yoshinori, Horiguchi Kentaro, Nakano Shigeki, Origuchi Shinichi, Aoyagi Kyoko, Serizawa Toru, Yamakami Iwao, Iwadate Yasuo
Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
Department of Neurosurgery, Chiba Cerebral and Cardiovascular Center, Ichihara, Japan.
J Neurosurg Case Lessons. 2021 Nov 1;2(18):CASE21487. doi: 10.3171/CASE21487.
Anatomical variations, such as high jugular bulbs and air cell development in the petrosal bone, should be evaluated before surgery. Most bone defects in the internal auditory canal (IAC) posterior wall are observed in the perilabyrinthine cells. An aberrant vascular structure passing through the petrous bone is rare.
A 48-year-old man presented with a right ear hearing disturbance. Magnetic resonance imaging revealed a 23-mm contrast-enhancing mass in the right cerebellopontine angle extending into the IAC, consistent with a right vestibular schwannoma. Preoperative bone window computed tomographic scans showed bone defects in the IAC posterior wall, which ran farther posteroinferiorly in the petrous bone, reaching the medial part of the jugular bulb. The tumor was accessed via a lateral suboccipital approach. There was no other major vein in the cerebellomedullary cistern, except for the vein running from the brain stem to the IAC posterior wall. To avoid complications due to venous congestion, the authors did not drill out the IAC posterior wall or remove the tumor in the IAC.
Several aberrant veins in the petrous bone are primitive head sinus remnants. Although rare, their surgical implication is critical in patients with vestibular schwannomas.
在手术前应评估解剖变异情况，如高位颈静脉球和岩骨内气房发育情况。内耳道（IAC）后壁的大多数骨缺损见于迷路周围气房。穿过岩骨的异常血管结构罕见。
一名48岁男性因右耳听力障碍就诊。磁共振成像显示右侧桥小脑角有一个23毫米的强化肿块延伸至内耳道，符合右侧前庭神经鞘瘤。术前骨窗计算机断层扫描显示内耳道后壁有骨缺损，该缺损在岩骨内更向后下方延伸，到达颈静脉球内侧部分。通过枕下外侧入路处理肿瘤。除了从脑干延伸至内耳道后壁的静脉外，小脑延髓池内没有其他主要静脉。为避免静脉淤血导致的并发症，作者未钻开内耳道后壁或切除内耳道内的肿瘤。
岩骨内的几条异常静脉是原始头窦的残余。虽然罕见，但它们对前庭神经鞘瘤患者的手术意义重大。
