Cranio-vertebral transition assessment by magnetic resonance imaging in a sample of a northeast Brazilian population

Abstract

The cranio-vertebral transition (CVT) is composed by the base of the occipital bone and the first two cervical vertebrae, atlas and axis (C1 and C2, respectively). This region is susceptible to conformational abnormalities, such as platybasiaflattening of skull base -and basilar invagination -protrusion of the tooth of the C2 to the posterior fossa. They are mutually associated, and both may also relate to cerebellar tonsil herniation. Clinical repercussions are varied and derive from compression of nervous structures or obstruction of cerebrospinal fluid circulation, with consequent hydrocephalus and syringomyelia 1 . Imaging exams are indispensable in the assessment of CVT, and the gold-standard is magnetic resonance imaging (MRI), especially because it can demonstrate both musculoskeletal and nervous elements involved. Craniometric imaging parameters were first established last century, notably from German Conclusão: Houve uma tendência a platibasia, invaginação basilar e estreitamento da transição craniovertebral, que poderiam ser influenciados pela natureza multirracial e por fatores antropológicos da população estudada.Palavras-chave: platibasia; imagem por ressonância magnética; circunferência craniana.

Craniometric parameters for the evaluation of platybasia and basilar invagination on magnetic resonance imaging: a reproducibility study

“…The shape of the skull can vary among different populations, being dependent on ethnic, anthropological, and geographical factors (10,11,13,29) . For example, brachycephaly is much more prevalent in certain regions, such as northeastern Brazil and Southeast Asia (7,9,13) .…”

“…Anomalies of the CVJ are particularly common in India and in the northeastern region of Brazil (7)(8)(9) ; it is notable that nearly all cases in northeastern Brazil are of type B, whereas nearly half of those in India are of type A. In both of those countries, the reported number of surgical cases is among the largest in the world (10)(11)(12) . Studies indicate that type B basilar invagination may be related to the flattened conformation of the calvaria, or brachycephaly, a phenotype found in approximately 80% of the population in northeastern Brazil, a prevalence much higher than that found in samples from western Europe and the North America (10,13) .…”

“…Studies indicate that type B basilar invagination may be related to the flattened conformation of the calvaria, or brachycephaly, a phenotype found in approximately 80% of the population in northeastern Brazil, a prevalence much higher than that found in samples from western Europe and the North America (10,13) . Since 2013, Frade et al (11) have been using MRI to evaluate skull samples from northeastern Brazil. The authors found evidence that CVJ anomalies are more prevalent in the inland zone than in the coastal zone.…”

Craniocervical junction abnormalities in northeast Brazilian population

“…Short and wide cranium and high faces characterized the cranial morphology of this era. Therefore this tendency for braquicephaly, platibasia and basilar invagination on Northeastern Brazilians is believed to be inherited from pre-historic ancestors.In this issue of Arquivos de Neuropsiquiatria Frade et al 4 revived those concepts measuring Chamberlain's line, that evaluate basilar invagination, and median clivus-canal and Welcher basal angles, that evaluate platibasia, utilizing MRI in asymptomatic subjects of the Brazilian Northeast. They found a tendency to platibasia and basilar invagination on their population.…”

“…In this issue of Arquivos de Neuropsiquiatria Frade et al 4 revived those concepts measuring Chamberlain's line, that evaluate basilar invagination, and median clivus-canal and Welcher basal angles, that evaluate platibasia, utilizing MRI in asymptomatic subjects of the Brazilian Northeast. They found a tendency to platibasia and basilar invagination on their population.…”