Journal of Pediatric Neurosciences
: 2019  |  Volume : 14  |  Issue : 4  |  Page : 179-

Chiari 1 malformation: Revisited

Dattatraya Muzumdar 
 Professor, Department of Neurosurgery, Seth G.S. Medical College and King Edward VII Memorial Hospital, Parel, Mumbai, Maharashtra, India

Correspondence Address:
Dr. Dattatraya Muzumdar
FRCSI, FACS, Professor, Department of Neurosurgery, Seth G.S. Medical College and King Edward VII Memorial hospital, Parel, Mumbai-400012, Maharashtra.

How to cite this article:
Muzumdar D. Chiari 1 malformation: Revisited.J Pediatr Neurosci 2019;14:179-179

How to cite this URL:
Muzumdar D. Chiari 1 malformation: Revisited. J Pediatr Neurosci [serial online] 2019 [cited 2023 Nov 29 ];14:179-179
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Full Text

Hans Chiari was the first to describe changes in cerebellum, pons and medulla oblongata due to congenital hydrocephalus of the cerebrum in his monograph in 1892. Subsequently he had divided these into three types and subsequently added the fourth type.

Chiari 1 malformation was reported to be associated with hydrocephalus. The treatment has been the ‘top to down’ algorithm viz. CSF diversion, foramen magnum decompression with or without duroplasty. This was primarily based on the theories explaining the CSF flow dissociation at the foramen magum, the ‘piston effect’ or ‘water –hammer’ effect.

Over the years, evolving clinical experience and research on this complex subject revealed that Chiari 1 malformation has varied causes and the pathophysiology is peculiar to each of them. Thus the treatment paradigms are different in each of them. This has been corroborated with experience from multiple centers treating Chiari 1 malformation. The types of surgeries performed vary widely from decompression of foramen magnum with or without duroplasty, fixation of the craniovertebral junction or detethering of spinal cord by sectioning the filum terminale.

The main reason for such variability reflects in the evolving understanding of the genesis of Chiari 1 malformation. The Chiari 1 malformation can have a genetic basis or secondary to a host of conditions viz. craniosynostosis or rasopathies, craniocerebral disproportion, CSF circulation abnormality, platybasia, secondary neurulation abnormalities, bone metabolic disorders etc. The whole genome sequencing on large patient cohort will enhance understanding on the subject. This will help to counsel the patient regarding the clear risk of Chiari 1 malformation in relatives of affected patients.

Chiari 1 malformation has no acceptable universal definition amongst clinicians due to the distinct incongruity in clinicoradiological correlation. It is generally acquired and potentially reversible anomaly. There are a number of publications on the subject but simultaneously controversies have also increased proportionately. Many cases are found incidentally and have no clinical symptomatology. In view of the evolving understanding of Chiari 1 malformation, there is a current debate is whether Chiari 1malformation should be termed as malformation or a ‘hind brain hernia’. A likely consensus is currently in the process of being formed and may become universally acceptable definition in the future.

There is not enough data to predict or suggest accuracy of evolution, clinical presentation, imaging findings, surgical technique, and role of intraoperative neurophysiologic monitoring in treatment of Chiari 1 malformation. A multicentric randomized study will be certainly helpful to collate more information on the complex subject, which seemingly appears to be simple by addressing it as abnormal descent of tonsils.

There is no clear consensus amongst clinicians to advise a defined algorithm for management of Chiari 1 malformation. This is corroborated by institutional experience of summated cases of Chiari 1 malformation, which may lack uniformity in case selection or procedure until date. Probably only secondary syrinx formation might mandate some form of treatment to alleviate radiological progression and /or stabilize symptoms presumably related to Chiari 1 malformation.

Chiari 1 malformation and its controversies formed an important theme during the 47th Annual meeting of the International Society for Pediatric Neurosurgery held at Birmingham from October 20 to 24, 2019. The annual issue of Child’s nervous system is entirely devoted to this important and relevant topic in clinical practice, which is commonly encountered, by pediatric neurosurgeons throughout the world.