thoracolumbar extradural arachnoid cysts: report of two adult cases

Background and aim: extradural spinal arachnoid cysts are a rare compressive pathology of the spinal cord. they are believed to arise from congenital defects in the dura mater, with gradual enlargement occurring over time. the mainstay of treatment for spinal extradural arachnoid cysts (edacs) consists of closing the minute dural defect or ostia through which the arachnoid layer has subsequently herniated. exposure and ligation of the fistula tract at the ostia can then be achieved by utilizing either multilevel or single level laminectomy.case presentation: two cases are presented herein that exhibited progressive weakness of the lower limbs. magnetic resonance imaging in both patients displayed an extradural cystic mass at the thoracolumbar spine compatible with an extradural arachnoid cyst. in each case, following surgical excision of the arachnoid cyst, the corresponding ostia or tiny dural defect was securely closed with silk sutures. postoperatively, neither patient reported any issues related to recovery during a six-month follow-up encounter.conclusion: edacs are rare, benign, but potentially debilitating causes of spinal cord compressions. the mainstay of treatment is the closure of the dural defect or ostia. if the radiological localization of the ostia can be identified preoperatively, selective closure of the ostia using a minimally invasive surgical procedure is the intervention of choice. otherwise, closure of the dural defect will be possible following a multilevel laminectomy and total resection of the arachnoid cyst.