Chiari Malformations: A Review of the Current Literature

Abstract

Chiari malformations (CM) are a group of malformations involving the posterior fossa and rhombencephalic structures that may have other associated intra- or extracranial defects. Initially, the 4 classic varieties were described by the Austrian pathologist Hans Chiari towards the end of the 19th century; years later, the Swiss pathologist Julius Arnold described a case of type II CM with associated myelomeningocele. years later, two of his students used the term "Arnold-Chiari Malformation", this term is often misused for all types. Currently it is estimated that the incidence and prevalence data are underestimated due to the asymptomatic presentation of the pathology in many cases and the limited access to health services of different populations at a global level, for this reason the epidemiological data vary between the literature. The original classification has been modified by contributions from various authors in order to more precisely describe the variety of morphological findings; currently the classification includes CM types 0, I, 1.5, II, III and IV. The symptoms and associated pathological conditions vary for each type and type III and IV are the most severe forms. Diagnosis requires that secondary causes of cerebellar tonsillar ectopy (main finding of CM) be ruled out, along with a physical examination, neurological evaluation, and complementary tests; however, diagnosis requires resonance neuroimaging to demonstrate the findings. The management basically consists of performing a decompression of the posterior fossa and whose main indication is to reduce the symptoms, however, it should be noted that there is no global agreement among specialists on the subject of surgical management, for which each patient must be individualized by your treating physician and the decision made is subject to individual criteria.