Spina bifida with hydrocephalus. Assessment of Chiari malformation. Brain:Findings related to previous suboccipital decompressive craniectomy are present. Since the previous examination, new, severe dilatation of the ventricular system has occurred, including the fourth ventricular outflow tracts. Fourth ventricular dilatation is more focally pronounced along the inferior aspect of the ventricle and results in downward displacement of the cervicomedullary junction and obex into the upper cervical spinal canal. The cerebellar tonsils are posteriorly pushed rather than inferiorly displaced through foramen magnum. This is suggestive of obstruction at the level of the median foramen. There is also severe inferior displacement and thinning of the floor of the third ventricle (hypothalamus) which is now partially behind the dorsum sellae which shows pressure thinning. There is postchiasmatic splaying of the optic tracts by the dilated and third ventricle. This ventricular dilatation is associated with periventricular white matter T2 hyperintensity indicating transependymal CSF flow. Given the bilateral, symmetric nature of the ventricle dilatation, there is no midline shift. The sulci are relatively compressed. There is no space-occupying brain lesion, otherwise. The major intracranial vessels are patent.The CSF flow study shows pulsatile flow in the CSF spaces above and below the foramen magnum but not through it. Whole Spine:The above-described new dilatation of the ventricular system is associated with marked progression of the cervicothoracic syrinx (hydromyelia and syringomyelia) which is now associated with expansion of the spinal cord. The abnormality reaches to the lower T11 vertebral level. The tip of the conus medullaris is at the mid L2 level. The conus has normal morphology.There is a mild sigmoid-shaped scoliosis (rightward convex in the thoracic spine with compensatory lumbar and cervical curvatures). This is not associated with morphologic abnormality of the vertebrae.
Since August 2013, there has been significant progression of dilatation of the ventricular system as well as the cervicothoracic syrinx. This is suggestive of obstruction at the level foramen magnum.