Current Concepts in the Pathogenesis, Diagnosis, and Management of Type I Chiari Malformations.

Type 1 Chiari malformations (CMs) are a group of congenital or acquired disorders which include the abnormal presence of the cerebellar tonsils in the upper spinal canal, rather than the posterior fossa. The resulting anatomic abnormality causes crowding of the structures at the craniocervical junction and can impair the normal flow of cerebral spinal fluid (CSF) in this region. This impairment in CSF flow dynamics can led to the development of syringomyelia or hydrocephalus. Type 1 CMs have been associated with a wide array of symptoms resulting from either cerebellar and brainstem compression and distortion or disturbances in CSF dynamics, and can affect both children and adults. The clinical diagnosis may be difficult. Age usually matters in the clinical presentation, and in symptomatic patients, surgical intervention is usually required. [Full article available at http://rimed.org/rimedicaljournal-2017-06.asp].