Basilar invagination associated with chiari malformation type I: A literature review

Basilar invagination (BI) and Chiari malformation type I (CM-I) are very important anomalies that introduce instability and compression in the occipitocervical transition region and have complex clinical characteristics. These anomalies vary according to the affected structures. The present study revises current knowledge regarding the anatomy, anatomo-physiology, clinical manifestations, and radiological findings of these entities and the associated surgical treatment approaches. A bibliographic survey was performed through a search in the Medline, PubMed, SciELO, Science and LILACS databases. When associated, these craniovertebral malformations result in neurological deficits due to neural parenchyma compression; however, the presence of microtraumas due to repetitive lesions caused by the bulb and cervical marrow instability has been highlighted as a determinant dysfunction. Surgical treatment is controversial and has many technical variations. Surgery is also challenging due to the complex anatomical characteristics and biomechanics of this region. Nevertheless, advances have been achieved in our understanding of related mechanisms, and compression and atlantoaxial instability are considered key elements when selecting the surgical approach.

Ocorrência de epilepsia na impressäo basilar / Ocurrence of epilepsy in basilar impression

Os autores analisam crises epilépticas observadas em 12 (5,2%) pacientes dentre os 230 casos operados de impresäo basilar e/ou malformaçäo de Arnold-Chiari. Algumas consideraçöes säo feitas em relaçäo às crises epilépticas e estados sincopais com o intuito de esclarecer melhor estas ocorrências clínicas. Mecanismos fidiopatogênicos, baseados em dados anatômicos e clínicos, säo propostos para os casos em estudo