[Chiari malformation].

The Chiari malformation (CHM) is a congenital disease of unknown etiology. It is presumed that a defective closure of the neural tube produces at least one of its three types. It has also been related to traumatic delivery. Type II is closely associated to the myelomeningocele. The clinical picture is determined by the chronic compression of the cervical cord by the cerebellar tonsils. Low cranial nerve palsy and muscular hypotonia are some of its predominant features. Syringomyelia complicates type I. CAT scan and NMR are the preferred radiological studies for diagnosing MCH. Treatment is surgical. Posterior fossa decompression and cervical laminectomy are sufficient if the ventricular shunt is patent. If treatment is installed before permanent structural damage is present, up to 88% of the patients have significant remission of the symptoms.