Resolution of syndromic craniosynostosis-associated Chiari malformation Type I without suboccipital decompression after posterior cranial vault release

Case report

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Chiari malformation Type I (CM-I) is associated with syndromic and nonsyndromic craniosynostosis in pediatric patients, and the surgical management of CM-I in such cases is controversial. Previous guidelines have recommended simultaneous cranial vault expansion and suboccipital decompression. However, spontaneous resolution of CM-I has been observed, and the combined procedure carries additional surgical risks. The authors report the case of a 6-month-old boy with Crouzon syndrome, CM-I, and a cervical syrinx who underwent posterior cranial vault release without suboccipital decompression. Imaging at the 3-month follow-up visit demonstrated complete resolution of the CM-I, improvement in CSF flow, and reduction in the size of the syrinx. This case suggests that up-front suboccipital decompression may not be necessary in patients with craniosynostosis and CM-I. A strategy of initial cranial vault release, followed by watchful waiting and radiographic surveillance, is proposed.

Abbreviations used in this paper:CM-I = Chiari malformation Type I; ICP = intracranial pressure.

Article Information

Address correspondence to: Jeffrey G. Ojemann, M.D., Department of Neurological Surgery, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, Washington 98105. email:

Please include this information when citing this paper: DOI: 10.3171/2011.11.PEDS11268.

© AANS, except where prohibited by US copyright law.



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    Preoperative CT scans with 3D reconstructions. Significant right frontal bossing (arrows), occipital constriction, left coronal synostosis (asterisks), and sagittal synostosis are visible on frontal (A) and birds-eye (B) views. Extensive parietooccipital calvarial thinning with multiple osseous defects and bilateral lambdoid synostosis is seen on the posterior projection (C).

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    Preoperative MR imaging studies of the brain and spine. A: Sagittal T1-weighted brain MR imaging study demonstrating significant tonsillar herniation (line) 11 mm below the foramen magnum. B: Sagittal T2-weighted MR imaging study of the spine showing a 3-mm cervical syrinx (arrow).

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    Postoperative CT scans with 3D reconstructions. The parietooccipital osteotomies (asterisk) and en bloc craniectomy (arrow) are visible on the lateral projection (A). Posterior view (B) shows the intact suboccipital calvaria (arrow); no decompression was performed. A surgical drain is visible overlying the anterior vertex.

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    Postoperative MR imaging studies of the brain and spine at the 3-month follow-up visit. A: Sagittal T1-weighted MR imaging study of the brain demonstrating complete resolution of the cerebellar tonsillar herniation (arrow). B: Sagittal T2-weighted spinal MR imaging study showing a reduction in the size of the cervical syrinx (arrow).



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