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OBJECTIVE: To evaluate the effect of the basilar invagination (BI) type B on cervical spine. METHODS: The research protocol used head magnetic resonance imaging (MRI) exams from 41 participants with BI type B and 158 controls. The criterion for BI was the distance of the odontoid apex to Chamberlain's line (DOCL) equal to or greater than 7 mm. The clivus length (CLI), clivus canal angle (CCA), Welcker's basal angle (WBA), Boogaard's angle (BOA), upper cervical lordosis angle (UCL), and total cervical lordosis angle (CL) were evaluated. The descriptive analysis, group comparisons, and correlations between skull base and cervical spine parameters were performed at the 95% CI. RESULTS: Participants with BI type B showed shorter clivus length (CLI: 25.7 ± 7.3 mm); greater angulation of the skull base (WBA: 126.5 ± 10.4); greater inclination foramen magnum (BOA: 151.5 ± 14.5); decrease in the value of the CCA (131.6 ± 15); and greater angulations of UCL (17.9 ± 13.8) and CL (29.7 ± 19.9) in comparison to the control group (P < 0.05). Clivus length and CCA correlated inversely with UCL and CL, while BOA correlated directly with UCL and CL. The WBA did not correlate with CL (P < 0.05). CONCLUSIONS: The deformation of skull base in the BI of type B caused, on average, a hyperlordosis of almost 30° in the C2-C6 segment. This change was approximately 17° in the C2-C4, with the clivus hypoplasia being a risk factor for cervical hyperlordosis.
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OBJECTIVE: To analyze the association between basilar invagination (BI) and stenosis in the hypoglossal canal (HC). METHODS: A case-control study with magnetic resonance images (MRIs) of the head from a local database was performed. The study used MRIs of 31 patients with BI (type B) and 36 controls, both groups over 18 years of age and without sex distinction. The internal (ID) and external (ED) diameters of the HC were measured on the coronal plane using the Osirix in its free version 3.9.2 (Mac-Apple platform). We used the Kolmogorov-Smirnov test (with Lilliefors adjustment) to evaluate the normality of the variables, the Levine test to verify the homogeneity of the variances, and Student's t test to verify differences between groups. All analyses were within the 95% confidence interval. RESULTS: Control group presented right and left ED values of 4.7 ± 0.8 mm and 4.6 ± 0.9 mm, respectively, while the right and left ID showed 4.4 ± 0.9 mm and 4.3 ± 0.8 mm, respectively. The group with BI showed right and left ED values of 3.3 ± 0.9 mm and 3.1 ± 0.9 mm, and the right and left ID had values of 2.8 ± 0.7 mm and 2.7 ± 0.7 mm, respectively. Both ED and ID were smaller in the group with BI (P < 0.001). CONCLUSIONS: Patients with BI of type B presented the narrowing of HC when compared with control participants.
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Foramen Magno/anomalías , Platibasia/patología , Adulto , Anciano , Articulación Atlantooccipital/anomalías , Estudios de Casos y Controles , Constricción Patológica , Femenino , Humanos , Nervio Hipogloso , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: To evaluate the diagnostic accuracy of classical measurements for basilar invagination (BI) of type B at MRI. METHODS: This study used head MRIs from 31 participants with BI type B and 96 controls. The radiological criterion for BI was the odontoid process invagination using the obex as reference. It based on the independent prospective reading of two neuroradiologists. Concordance between the two neuroradiologists was analysed through the KAPPA index, and the discrepancy was resolved in a consensus meeting. A third examiner measured in two occasions (double blind) the distance of the odontoid apex to Chamberlain's line (DOCL) and McGregor's line (DOMG), clivus canal angle (CCA), Welcker's basal angle (WBA), and Boogaard's angle (BOA). Intra-examiner reproducibility of the measurements was evaluated with the intraclass correlation coefficient and the diagnostic accuracy by ROC curve. All analyses were at 95% confidence interval. RESULTS: Agreement between the two neuroradiologists was statistically relevant (KAPPA = .91; P = .0001). The intra-examiner reproducibilities were .98 (DOCL), .97 (DOMG), .96 (CCA), .94 (WBA), and .95 (BOA) (P < .05). The areas under the ROC curve were .963 (DOCL), .940 (DOMG), .880 (CCA), .867 (WBA), and .951 (BOA) (P < .05). The cut-off criteria were ≥ 7 mm (DOCL), ≥ 8 mm (DOMG), ≤ 145° (CCA), ≥ 142° (WBA), and ≥ 136° (BOA). The diagnostic accuracies were .904 (DOCL), .870 (DOMG), .844 (CCA), .810 (WBA), and .899 (BOA). CONCLUSION: The DOCL and BOA presented the highest diagnostic accuracy for BI type B. These slides can be retrieved under Electronic Supplementary Material.
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Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/normas , Platibasia/diagnóstico por imagen , Humanos , Variaciones Dependientes del Observador , Apófisis Odontoides/diagnóstico por imagen , Radiografía , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Basilar invagination (BI) is an abnormality characterized by a superior projection at the craniovertebral junction (CVJ). The high prevalence of BI in Northeastern Brazil associated with brachycephaly, which is measured by the cranial index (CI), has been widely reported by several neurosurgeons and radiologists from that region since the 1950s. However, strong evidence for this relationship is still pending. The aim of this study is to investigate whether there is a relationship between BI and CI in a sample with participants from Northeastern Brazil. METHODS: The study used magnetic resonance images (MRIs) from 34 patients with BI and 92 controls. These participants had the CI correlated with radiological measurements used in BI diagnosis: Welcker's basal angle (WBA), clivus-canal angle (CCA), apex distance of the odontoid process to Chamberlain's line (DOCL), and Boogaard's angle (BOA). Craniometry was performed using the software Osirix, version 3.9.2 and statistical analysis by SPSS. We used Pearson's test for correlation analysis and the ROC curve was used for depicting CI accuracy related to BI diagnosis. All tests were calculated at the 95% confidence interval. RESULTS: The BI group showed a moderate correlation between CI and CVJ measurements (Pâ¯<â¯0.05). The control group had a weak correlation between CI and DOCL, and no statistical significance was verified for other correlations (Pâ¯>â¯0.05). The area under the ROC was 0.659 and a CI greater than 86 had a specificity of approximately 80% for BI (Pâ¯=â¯0.002). CONCLUSIONS: The results indicated a greater cephalic projection of the CVJ in patients with high CI in the BI group. Moreover, a CI above 86 has a good diagnosis specificity for BI, showing evidence of a relationship between hyperbrachycephaly and CVJ anomalies in Northeastern Brazil.