Abstract： Objective To study the efficacy of microsurgical cyst resection and closure of the dural defect,while minimizing functional damage to neural tissues and spinal structure. Methods We retrospectively reviewed the records of 11 patients with intraspinal extradura] meningeal cysts who were treated microsurgically between 1996 and 2007. The patients presented lower extremity weakness,numbness,low back pain with radiacular radiation,and urinary dysfunction. Vertebral roentogenograms revealed an enlarged interpedicular space. Magnetic resonance (MR) imaging demonstrated extradural cystic lesions which were hypointense in Tl-weighted images and hyperintense in T2-weighted images mimicking the signal of CSF. We performed laminectomies or hemilaminectomies with microsurgical cyst resection and closure of the dural defect,using intraoperative electromyography to minimize damage to the nerve roots. Results The patients with motor deficits and bladder dysfunction recovered gradually. In 4 out of 5 patients the preoperative radicular pain improved markedly. No new postoperative neurological deficits were observed. Conclusions Spinal extradural cysts can be caused by anrachnoid herniation through dural defect. A valve mechanism promotes cyst progression. Microsurgical cyst resection and closure of the dural defect is effective and optimal therapeutic strategy. It is important to minimize the surgical damage to spinal stability and neural tissues.