[Brain changes in dysraphic syndromes occurring in cases of meningomyelocele]

Neural tube defects are the most common anomalies of the CNS in the group of dysraphic syndromes. They occur on both encephalic and spinal levels. According to the title of this article we discuss some characteristic examples of intracranial, encephalic changes occurring in cases of meningomyeloceles. The special position has to be attributed to Arnold-Chiari or Chiari malformation, being currently under a nosological discussion. It is often restricted to its most typical form-Chiari II syndrome. This is characterized by the neural tube defect and the posterior fossa and brain-stem-cerebellum malformation with a displacement into the foramen magnum. The compression of the fourth ventricle and even secondary necrotic changes are also seen. Clinical symptoms depend on the topography of pathological changes. Chiari II malformation coincides in the majority of cases with meningomyeloceles and sometime with other spinal cord malformations. Meningomyeloceles coincide often with anomalies within cerebral hemispheres. Among them hydrocephalus deserves particular attention, occurring in the majority of Chiari II cases and not being rare in cases of myeloceles. The anomalies and/or secondary lesions of encephalic structures, particularly of the cortical mantle are observed, depending upon the severity of hydrocephalus and the onset of its development. Meningomyeloceles can also be accompanied by cerebral hemispheres anomalies arising in the other pathomechanism and developmental period than dysraphic syndromes. The midline malformations and anomalies of commissural system are not rare among them. In conclusion we emphasize that each case of CNS malformations is unique. The observed anomalies have to be assessed whether they form a part of a leading syndrome or occur together with dysraphic changes.