title: Intraspinal extradural meningeal cyst demonstrating ball-valve mechanism of formation. Case report.
abstract: A diverse collection of unverified theories as to the etiology of extradural meningeal cysts have been previously proposed. One case of intraspinal extradural meningeal cyst of the thoracolumbar region is presented in which a ball-valve mechanism involving an idiopathic dural rent and a herniated segment of an underlying dorsal rootlet was suggested by the operative findings. Closure of the dural rent with marsupialization of the meningeal cyst obliterated this extradural lesion. The ball-valve mechanism of formation and other previously proposed theories are discussed.
authors.affiliation: Department of Neurosurgery, Oregon Health Sciences University, Portland.
authors.forename: D C
authors.initials: DC
authors.lastname: Rohrer
authors.forename: K J
authors.initials: KJ
authors.lastname: Burchiel
authors.forename: D P
authors.initials: DP
authors.lastname: Gruber
mesh_terms: D000328:Adult; D003560:Cysts / Q000150:complications / Q000503:physiopathology*; D004388:Dura Mater; D006801:Humans; D008297:Male; D013117:Spinal Cord Compression / Q000209:etiology*; D013118:Spinal Cord Diseases / Q000150:complications / Q000503:physiopathology*; D013126:Spinal Nerve Roots / Q000503:physiopathology