Chiari Malformation Associated With Craniosynostosis

Jennifer Strahle, M.D.; Karin M. Muraszko, M.D.; Steven R. Buchman, M.D.; Joseph Kapurch, B.S.; Hugh J. L. Garton, M.D., M.H.Sc.; Cormac O. Maher, M.D.


Neurosurg Focus. 2011;31(3):e2 

In This Article


We performed a retrospective single-center review of all patients under 18 years of age who were treated for craniosynostosis between 1994 and 2009. The University of Michigan institutional review board granted approval for the study. For this analysis, craniosynostosis was defined as clinical or radiological evidence of premature fusion of at least one cranial suture. Chiari malformation was defined as cerebellar tonsillar descent greater than or equal to 5 mm below the foramen magnum.[23,29] In each case, we recorded demographic information, characteristics of the craniosynostosis including suture location, and the number of sutures involved. When pre- or postoperative imaging studies were performed (Table 1), we recorded characteristics of the CM including a measurement of tonsillar descent below the foramen magnum, CSF flow analysis data on cine MR imaging, and any associated findings on imaging including venous anomalies and hydrocephalus. Cerebrospinal fluid flow data were recorded for all patients in whom dedicated CSF flow sequences were shown on MR imaging. At our institution, changes in signal intensity on sagittal phase-contrast CSF flow studies are observed in the CSF spaces anteriorly and posteriorly at the level of the cervicomedullary junction. The alternating bright and dark signals seen in the CSF spaces in the cine mode are diminished or absent when there is abnormal flow. On the axial and sagittal phase-contrast images, any change in the signal intensity of the cerebellar tonsils in the cine mode suggests tonsillar pulsations. Cerebrospinal fluid flow was categorized as abnormal if flow was decreased anteriorly or posteriorly at the foramen magnum or decreased at the foramen magnum with abnormal tonsillar pulsations based on the initial report of the radiologist. Surgical results were recorded for those patients who underwent craniosynostosis repair with or without CM decompression.


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