Ossified pseudomeningocele following Chiari decompression surgery in a patient with Kleeblattschädel deformity

Case report

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The authors present the case of a 3-year-old child with Kleeblattschädel, or cloverleaf skull deformity, and a Chiari malformation Type I who developed an ossified pseudomeningocele after posterior fossa decompression. To their knowledge, this is the first report of a postoperative ossified pseudomeningocele in a patient with Kleeblattschädel and the only case of an ossified pseudomeningocele located outside the lumbosacral region. A genetic basis for the ossification process seems likely given the child's history of premature cranial suture closure. The authors draw attention to this rare complication and review the available body of literature on this topic.

Abbreviations used in this paper: CM-I = Chiari malformation Type 1; CSF = cerebrospinal fluid.

Article Information

Address correspondence to: Matthew R. Reynolds, M.D., Ph.D., Barnes-Jewish Hospital, Department of Neurosurgery, 660 South Euclid Avenue, Campus Box 8057, St. Louis, Missouri 63110. email: reynoldsm@wudosis.wustl.edu.

© AANS, except where prohibited by US copyright law.



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    Three-dimensional CT reconstructions demonstrating anteroposterior (A), lateral (B), and posteroanterior (C) views of the child's initial Kleeblattschädel skull deformity.

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    Preoperative parasagittal MR images. Left: A T1-weighted MR image showing the CM-1. Right: A T2-weighted MR image demonstrating cervical cord compression, edema, and a developing syrinx.

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    Postoperative parasagittal MR images. A T1-weighted image (left) and a T2-weighted image (right) demonstrating a suboccipital pseudomeningocele as well as decreased cervical spinal cord edema.

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    Axial bone window CT scans. A and B: Scans of the head demonstrating posterior calcification of the pseudomeningocele. Panel A shows the superior aspect of the posterior fossa decompression with the developing calcification. C: Scan obtained at the level of the C-1 laminectomy showing absence of reossification at the laminectomy site.



Angle CRMcIntire MSMoore RC: Cloverleaf skull: Kleeblattschädel-deformity syndrome. Am J Dis Child 114:1982021967


Bradley JPLevine JPMcCarthy JGLongaker MT: Studies in cranial suture biology: regional dura mater determines in vitro cranial suture fusion. Plast Reconstr Surg 100:109111021997


Carollo CRigobello LCarteri AMarin G: Postsurgical calcified pseudocyst of the lumbar spine. J Comput Assist Tomogr 6:6276291982


Cushing H: Experiences with cerebellar astrocytomas. A critical review of seventy-six cases. Surg Gynecol Obstet 52:1292041931


Cushing H: Experiences with cerebellar medulloblastomas: a critical review. Acta Pathol Microbiol Immunol Scand 7:1861930


Feingold MO'Connor JFBerkman MDarling DB: Kleeblattschädel syndrome. Am J Dis Child 118:5895941969


Ishaque MACrockard HAStevens JM: Ossified pseudomeningocoele following laminectomy: case reports and review of the literature. Eur Spine J 6:4304321997


Kim HJRice DPKettunen PJThesleff I: FGF-, BMP- and Shh-mediated signalling pathways in the regulation of cranial suture morphogenesis and calvarial bone development. Development 125:124112511998


Lee KSHardy IM II: Postlaminectomy lumbar pseudomeningocele: report of four cases. Neurosurgery 30:1111141992


Manley GTDillon W: Acute posterior fossa syndrome following lumbar drainage for treatment of suboccipital pseudomeningocele. Report of three cases. J Neurosurg 92:4694742000


McLaurin RLFord LE: Obstruction following posterior fossa surgery: the postoperative Dandy–Walker syndrome. Johns Hopkins Med J 122:3093181968


Miller PRElder FW Jr: Meningeal pseudocysts (meningocele spurius) following laminectomy. Report of ten cases. J Bone Joint Surg Am 50:2682761968


Nash CL JrKaufman BFrankel VH: Postsurgical meningeal pseudocysts of the lumbar spine. Clin Orthop Relat Res 75:1671781971


Roland PSMarple BFMeyerhoff WLMickey B: Complications of lumbar spinal fluid drainage. Otolaryngol Head Neck Surg 107:5645691992


Rosenblum DJDerow JR: Spinal extradural cysts: with report of an ossified spinal extradural cyst. AJR Radium Ther Nucl Med 90:122712301963


Saito HKawakami N: Postsurgical ossified extradural cyst of the lumbar spine: a case report. Spine 21:3863881996


Scatliff JHKummer AJFrankel SAGerman WJ: Cystic enlargement and obstruction of the fourth ventricle following posterior fossa surgery. The postoperative Dandy-Walker syndrome. AJR Radium Ther Nucl Med 88:5365421962


Schumacher HWWassmann HPodlinski C: Pseudomeningocele of the lumbar spine. Surg Neurol 29:77781988


Shifrin LZFrish EBen-Arie J: Postsurgical lumbar calcified extradural cyst. Report of a case. Spine 15:2292311990


Shimazaki KNishida HHarada YHirohata K: Late recurrence of spinal stenosis and claudication after laminectomy due to an ossified extradural pseudocyst. Spine 16:2212241991


Tsuji HHanda NHanda OTajima GMori K: Postlaminectomy ossified extradural pseudocyst. Case report. J Neurosurg 73:7857871990


Wilkie AO: Craniosynostosis: genes and mechanisms. Hum Mol Genet 6:164716561997


Wilkinson HA: Nerve-root entrapment in “traumatic” extradural arachnoid cyst. J Bone Joint Surg Am 53:1631661971




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