Foramen magnum decompression for Chiari I malformation: a procedure not to be underestimated.

Objective: Chiari I malformation may be treated with foramen magnum decompression (FMD). We aim to describe the symptoms with which patients initially present, and to determine the number and type of complications occurring after FMD for Chiari I malformation.

Methods: Retrospective review of medical records for patients who had FMD performed for Chiari I malformation between January 2009 and December 2011.

Spinal level of myelomeningocele lesion as a contributing factor in posterior fossa volume, intracranial cerebellar volume, and cerebellar ectopia.

Object: McLone and Knepper's unified theory of Chiari malformation Type II (CM-II) describes how the loss of CSF via the open posterior neuropore fails to create adequate distending pressure for the developing rhomboencephalic vesicle. The authors of the present article describe the relationship between the posterior fossa volume and intracranial cerebellar volume as being related to the distance from the obex of the fourth ventricle to the myelomeningocele lesion using a common mathematical model, the Hagen-Poiseuille law.

Methods: All newborns who required closure of a myelomeningocele at the authors' institution between 2008 and 2011 and who were between 4 weeks premature and 2 months, corrected gestational age, at the time of MRI were included in this study.