Chiari I-a 'not so' congenital malformation?

Childs Nerv Syst. 2019 Oct;35(10):1653-1664. doi: 10.1007/s00381-019-04296-9. Epub 2019 Jul 10.


The term Chiari I malformation (CIM) is imbedded in the paediatric neurosurgical lexicon; however, the diagnostic criteria for this entity are imprecise, its pathophysiology variable, and the treatment options diverse. Until recently, CIM has been considered to be a discrete congenital malformation requiring a uniform approach to treatment. Increasingly, it is recognised that this is an oversimplification and that a more critical, etiologically based approach to the evaluation of children with this diagnosis is essential, not only to select those children who might be suitable for surgical treatment (and, of course those who might be better served by conservative management) but also to determine the most appropriate surgical strategy. Whilst good outcomes can be anticipated in the majority of children with CIM following foramen magnum decompression, treatment failures and complication rates are not insignificant. Arguably, poor or suboptimal outcomes following treatment for CIM reflect, not only a failure of surgical technique, but incorrect patient selection and failure to acknowledge the diverse pathophysiology underlying the phenomenon of CIM. The investigation of the child with 'hindbrain herniation' should be aimed at better understanding the mechanisms underlying the herniation so that these may be addressed by an appropriate choice of treatment.

Keywords: CNS manifestations; Cerebellar tonsillar ectopia; Chiari I; Congenital malformation; Craniovertebral junction; Hindbrain hernia.

Publication types

  • Review

MeSH terms

  • Arnold-Chiari Malformation / classification*
  • Arnold-Chiari Malformation / diagnosis*
  • Arnold-Chiari Malformation / surgery
  • Humans
  • Neurosurgical Procedures / classification
  • Neurosurgical Procedures / methods
  • Pediatrics / classification
  • Pediatrics / methods
  • Terminology as Topic*