Computed tomography evaluation of the normal craniocervical junction craniometry in 100 asymptomatic patients.

OBJECT: Most of the craniometric relationships of the normal craniocervical junction (CCJ), especially those related to angular craniometry, are still poorly studied and based on measurements taken from simple plain radiographs. In this study, the authors performed a craniometric evaluation of the CCJ in a population without known CCJ anomalies. The purpose of the study was to evaluate the normal CCJ craniometry based on measurements obtained from CT scans. METHOD: The authors analyzed 100 consecutive CCJ CT scans obtained in adult patients who were admitted at their tertiary hospital for treatment of non-CCJ conditions between 2010 and 2012. A total of 17 craniometrical measurements were performed, including the relation of the odontoid with the cranial base, the atlantodental interval (ADI), the clivus length, the clivus-canal angle (CCA)-the angle formed by the clivus and the upper cervical spine, and the basal angle. RESULTS: The mean age of the 100 patients was 50.6 years, and the group included 52 men (52%) and 48 women (48%). In 5 patients (5%), the tip of the odontoid process was more than 2 mm above the Chamberlain line, and in one of these 5 patients (1% of the study group). it was more than 5 mm above it. One patient had a Grabb-Oakes measurement above 9 mm (suggesting ventral cervicomedullary encroachment). The mean ADI value was 1.1 mm. The thickness of the external occipital protuberance ranged from 7.42 to 22.36 mm. The mean clivus length was 44.74 mm, the mean CCA was 153.68° (range 132.32°-173.95°), and the mean basal angle was 113.73° (ranging from 97.06°-133.26°). CONCLUSIONS: The data obtained in this study can be useful for evaluating anomalies of the CCJ in comparison with normal parameters, potentially improving the diagnostic criteria of these anomalies. When evaluating CCJ malformations, one should take into account the normal ranges based on CT scans, with more precise bone landmarks, instead of those obtained from simple plain radiographs.

Incidence of basilar invagination in patients with tonsillar herniation? A case control craniometrical study.

A retrospective case-control study based on craniometrical evaluation was performed to evaluate the incidence of basilar invagination (BI). Patients with symptomatic tonsillar herniation treated surgically had craniometrical parameters evaluated based on CT scan reconstructions before surgery. BI was diagnosed when the tip of the odontoid trespassed the Chamberlain's line in three different thresholds found in the literature: 2, 5 or 6.6 mm. In the surgical group (SU), the mean distance of the tip of the odontoid process above the Chamberlain's line was 12 mm versus 1.2 mm in the control (CO) group (p<0.0001). The number of patients with BI according to the threshold used (2, 5 or 6.6 mm) in the SU group was respectively 19 (95%), 16 (80%) and 15 (75%) and in the CO group it was 15 (37%), 4 (10%) and 2 (5%).

Incidence of basilar invagination in patients with tonsillar herniation ? a case control craniometrical study / Incidência da invaginação basilar com heriação tonsilar ? estudo da craniometria do tipo caso-controle

A retrospective case-control study based on craniometrical evaluation was performed to evaluate the incidence of basilar invagination (BI). Patients with symptomatic tonsillar herniation treated surgically had craniometrical parameters evaluated based on CT scan reconstructions before surgery. BI was diagnosed when the tip of the odontoid trespassed the Chamberlain’s line in three different thresholds found in the literature: 2, 5 or 6.6 mm. In the surgical group (SU), the mean distance of the tip of the odontoid process above the Chamberlain’s line was 12 mm versus 1.2 mm in the control (CO) group (p<0.0001). The number of patients with BI according to the threshold used (2, 5 or 6.6 mm) in the SU group was respectively 19 (95%), 16 (80%) and 15 (75%) and in the CO group it was 15 (37%), 4 (10%) and 2 (5%).

Realizamos estudo retrospectivo tipo caso-controle baseado na avaliação craniométrica para avaliar a incidência da Invaginação Basilar (IB). Pacientes com herniação tonsilar sintomática tratada cirurgicamente foram avaliados quanto a parâmetros craniométricos obtidos em reconstrução de TC antes da cirurgia. IB foi diagnosticada quando a ponta do odontóide passava acima da linha de Chamberlain em 2, 5 ou 6,6 mm. No grupo cirúrgico (CI), a distância média da ponta do odontóide acima da linha de Chamberlain foi de 12 mm versus 1,2 mm no grupo controle (CO) (p<0.0001). O número de pacientes com IB conforme o critério diagnóstico usado (2, 5 ou 6,6 mm) foi de 19 (95%), 16 (80%) e 15 (75%) no grupo CI, respectivamente, contra 15 (37%), 4 (10%) e 2 (5%) no grupo CO. Pacientes com herniação tonsilar tinham maior incidência de IB comparados ao grupo controle.