Van Tıp Dergisi (Aug 2020)
Radiological Imaging Findings of Basilar Invagination
Abstract
INTRODUCTION: To evaluate craniometric measurements and accompanying additional pathologies in cases with basilar invagination on radiological imaging. METHODS: Between January 2010 and April 2020, cervical CT, cervical MRI and brain MRI with 18,190 examinations were analyzed retrospectively. If the extension of the odontoid to the cranial using the Chamberlain line was greater than 5 mm, that was called basilar invagination. The association of pathologies such as platybasia, Chiari malformation, Klippel-Feil Syndrome and occipital bone dysplasia in cases with basilar invagination were investigated. Frequency of detection of basilar invagination on radiological images and demographic data of the cases were examined. Welcher's basal angle measurements were made with the modified basal angle for the platybasia. RESULTS: Basilar invagination was detected in 64 cases, more frequently in women (73.44%). The incidence of basilar invagination on radiological examinations was 0.35%. The average age of cases with basilar invagination was 37.09 +- 14.23 (age range 7 - 64). The distance to reach the Chamberlain line cranial axis of the dens axis was measured as 10.61 +- 5.02 mm. Modified basal angle mean was 123.77 +- 6.76 degrees, and Welcher's basal angle mean was 138.79 +- 7.06 degrees in cases with basilar invagination. The most common finding accompanying basilar invagination was the platybasia (89.06%), followed by Chiari type 1 malformation, Klippel-Feil syndrome, and atlantooccipital assimilation, respectively. Only 22.8% of the cases detected with a modified basal angle measurement were able to detect the presence of Welcher's basal angle measurement. DISCUSSION AND CONCLUSION: Although basilar invagination is a rare craniocervical junction pathology, it may be associated with other pathologies such as platybasia and Chiari type 1 malformation.
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