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

Abstract

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.

Sectioning of the Filum Terminale in Patients with Chiari Malformation Type 1 Associated with Occult Tethered Cord Syndrome: Literature Review

“…8 If the herniation of the tonsils towards the upper medullary canal is greater than 5 mm, the condition is known as CM1. 9 This internal pressure in the spinal canal, especially in the presence of basilar invagination, which is often associated with Chiari, because it shares defects in the same anatomical region, leads to a blockage of the flow of cerebrospinal fluid (CSF) at the craniospinal junction. 10 Treatment is directed towards patients who exhibit symptoms, and it can be done with surgical and non-surgical approaches.…”

Anatomoclinical correlation and main radiological findings in a patient affected by Arnold Chiari's malformation: a review

“…Type II is configured as the most common in the entire world population and happens when there is also herniation of the cerebellar tonsils, besides, there is herniation of the cerebellar worm and displacement of the ventricle IV; In type III, there is the herniation of the cerebellum or brainstem bringing in most of the times a high cervical meningocele; in type IV, there is little cerebellar development, being important to point out that there is no herniation in this case (Brock et al, 2017;Brito, 2019;Santos et al, 2020).…”

Monitoring Skull Base Abnormalities in Children with Osteogenesis Imperfecta – Review of Current Practice and a Suggested Clinical Pathway

“…Mostly, the only symptom present is headache, and this can pose a diagnostic challenge [3]. Importantly, whilst platybasia is mostly asymptomatic and its clinical significance uncertain [7], the early diagnosis of basilar invagination is important, as treatment is beneficial in symptomatic cases [5,6]. Other abnormalities include compression of the structures of the posterior fossa, Chiari malformation, spinal cord syrinx, and hydrocephalus [4].…”