occurs during fetal development and is characterized by downward displacement by more than four millimeters, of the cerebellar tonsils beneath the foramen magnum into the cervical spinal canal.
characterized by downward displacement of the medulla, fourth ventricle, and cerebellum into the cervical spinal canal, as well as elongation of the pons and fourth ventricle. This type occurs almost exclusively in patients with myelomeningocele.
a form of dysraphism with a portion of the cerebellum and/or brainstem pushing out through a defect in the back of the head or neck. These malformations are very rare and are associated with a high early mortality rate, or severe neurological deficits in patients that survive
the most severe form and the rarest. The cerebellum fails to develop normally. There may be other associated malformations of the brain and brainstem. Most babies born with this malformation do not survive infancy.
NEUROSURGEONS f o r K i d s
CHIARI I MALFORMATION NEUROSURGEONS f o r K i d s
>90% of syrinxes will reduce in size after decompression 1
50-90% of patients will have improvement in their pre-operative symptoms 1,2
1 Time course of syringomyelia resolution following decompression of Chiari malformation Type I. Wetjen NM, Hiess JD, and Oldfield EH in J Neurosurg Pediatr. 2008 Feb;1(2):118-23
2 Outcome of Chiari-associated syringomyelia after hindbrain decompression in children: analysis of 49 consecutive cases. Attenello FI, McGirt MJ, Gathinii M et al in Neurosurgery. 2008 Jun;62(6):1307-13; discussion 1313