Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan.
J Clin Neurosci. 2011 Jun;18(6):863-4. doi: 10.1016/j.jocn.2010.10.013. Epub 2011 Apr 13.
Spinal extradural arachnoid cysts are thought to be extradural arachnoid pouches that communicate with the intraspinal subarachnoid space through a small dural defect. The mainstay of current treatment is resection of the cyst wall followed by obliteration of the communicating pedicle. Despite its clinical importance, the communicating pedicle of the cyst is often elusive. The authors report a 57-year-old woman with an extradural arachnoid cyst with intractable back pain and progressive motor weakness. Preoperative imaging studies, including phase-contrast MRI, failed to identify the communicating pedicle. Intraoperative Doppler ultrasonography clearly demonstrated the pulsatile influx of cerebrospinal fluid into the cyst. A flap-like structure was also noted near the pedicle; this structure appeared to act as a one-way valve. Doppler ultrasonography may be a helpful adjunct for identifying the location of elusive communication in a spinal extradural arachnoid cyst.
椎管外硬脊膜蛛网膜囊肿被认为是硬脊膜外蛛网膜的囊袋，通过小的硬脑膜缺损与椎管内蛛网膜下腔相通。目前的主要治疗方法是切除囊肿壁，然后闭塞交通支。尽管蛛网膜囊肿的交通支具有重要的临床意义，但它常常难以找到。作者报告了一例 57 岁女性，患有硬脊膜外蛛网膜囊肿，表现为顽固性背痛和进行性运动无力。包括相位对比 MRI 在内的术前影像学研究未能识别出交通支。术中多普勒超声检查清楚地显示出脑脊液脉冲式流入囊肿。在靠近交通支的地方还发现了一个瓣状结构；这个结构似乎起到了单向阀的作用。多普勒超声检查可能有助于识别椎管外硬脊膜蛛网膜囊肿中难以找到的交通部位。
