Rangel-Castilla Leonardo, Torres-Corzo Jaime, Vecchia Roberto Rodriguez Della, Mohanty Aaron, Nauta Haring J W
Division of Neurosurgery, University of Texas Medical Branch, Galveston, Texas 77555-0517, USA.
J Neurosurg Pediatr. 2009 Mar;3(3):225-31. doi: 10.3171/2008.11.PEDS08106.
Arachnoid cysts are congenital lesions that arise during development by splitting of the arachnoid membrane. Large cysts can be adjacent to CSF pathways causing a marked midline shift and hydrocephalus. The association between a large arachnoid cyst and hydrocephalus has been commonly described as being due to a mass effect, but these previous reports have not focused closely on any associated intraventricular abnormalities.
Seven patients who were previously treated with a cystoperitoneal shunt presented with shunt failure, hydrocephalus, and/or cyst expansion. All of these patients had giant arachnoid cysts extending to the periventricular region from the original site, which was the sylvian fissure in 4 patients, and the suprasellar cistern, quadrigeminal cistern, and interhemispheric fissure in 1 patient each. Endoscopic exploration of the ventricular system and cyst fenestration was then performed in all patients.
The endoscopic findings were obstruction of the cerebral aqueduct by a membrane not related to the cyst in 5 patients, occlusion of the foramen of Monro in 6, septum pellucidum hypoplasia in 2, and occlusion of the cerebral aqueduct by a quadrigeminal arachnoid cyst in 1. Endoscopic procedures performed were septum pellucidum fenestration and/or foraminoplasty in 5 patients, aqueductoplasty in 2, endoscopic third ventriculostomy in 5, fenestration of the lamina terminalis in 1, and direct cystocisternostomy in 1. After the endoscopic procedure, signs and symptoms of increased intracranial pressure and hydrocephalus improved in all patients, with a reduction in size of the cyst and the ventricle.
Ventricular abnormalities contributing to hydrocephalus may be associated with arachnoid cysts. These abnormalities may more likely reflect a common origin than a casual relation. Foramen of Monro stenosis and cerebral aqueduct occlusion associated with an arachnoid cyst can be more frequent than has been previously believed. In cases of periventricular giant arachnoid cysts, endoscopic exploration is a good alternative for examining the ventricular system and identifying and treating CSF obstructions caused by and/or related to arachnoid cysts.
蛛网膜囊肿是先天性病变，在发育过程中由蛛网膜分裂形成。大囊肿可毗邻脑脊液通路，导致明显的中线移位和脑积水。大蛛网膜囊肿与脑积水之间的关联通常被认为是由于占位效应，但以往这些报告并未密切关注任何相关的脑室内异常情况。
7例曾接受囊肿 - 腹腔分流术治疗的患者出现分流失败、脑积水和/或囊肿扩大。所有这些患者均有巨大蛛网膜囊肿从原部位延伸至脑室周围区域，其中4例原部位为外侧裂，1例分别为鞍上池、四叠体池和大脑镰旁裂。然后对所有患者进行脑室系统的内镜探查和囊肿开窗术。
内镜检查发现，5例患者中大脑导水管被与囊肿无关的膜阻塞，6例患者中室间孔闭塞，2例患者中透明隔发育不全，1例患者中四叠体蛛网膜囊肿阻塞大脑导水管。所施行的内镜手术包括5例患者的透明隔开窗术和/或造孔术，2例患者的导水管成形术，5例患者的内镜下第三脑室造瘘术，1例患者的终板开窗术，1例患者的直接囊肿 - 脑池造瘘术。内镜手术后，所有患者颅内压升高和脑积水的体征及症状均有改善，囊肿和脑室体积减小。
导致脑积水的脑室异常可能与蛛网膜囊肿有关。这些异常情况可能更倾向于反映共同起源而非偶然关系。与蛛网膜囊肿相关的室间孔狭窄和大脑导水管闭塞可能比之前认为的更为常见。对于脑室周围巨大蛛网膜囊肿病例，内镜探查是检查脑室系统以及识别和治疗由蛛网膜囊肿引起和/或与之相关的脑脊液梗阻的良好选择。
