Chiari anomaly is a congenital displacement of structures of the posterior cranial fossa in the caudal direction.
The occipital displacement of the tonsils of the cerebellum, for the diagnosis, should be at least 3 mm, and the displaced tonsils are triangular in shape. At the same time, the brain stem shifts forward, the large occipital tank is completely or subtotally occupied by the cerebellum. It should be noted that at the age of 5 to 15 years, the low location of the tonsils is not a pathology, but an age standard and requires observation in dynamics. Sometimes an additional protrusion on the posterior surface of the spinal cord, called the "spine" of the spinal cord and wide intertalamic fusion, is found.
Chiari anomaly of type I (Arnold-Chiari anomaly)
Chiari anomaly of type II
Chiari anomaly of III-IV type
The anomaly of Chiari I is combined with hydromia, Klippel-Feil syndrome, hydrocephalus, asymmetric atlas, basilar impression.
dystopia of the cerebellar tonsils (tonsillar ectopia)
hernia of the cerebellar tonsils (cerebral edema and wedging of the cerebellar tonsils into the large occipital orifice)
Operative treatment - decompression osteotomy of the large occipital foramen. In the presence of hydrocephalus, drainage of the ventricular system.
Author: Radiologist, Ph.D. Vlasov Evgeniy Alexandrovich
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