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Objectives: This study aimed to define the prevalence and characteristics of skull base anomalies and the features of sphenoid sinus pneumatization (SSP). Materials and Methods: Five hundred cone-beam computed tomography scans were evaluated retrospectively for the presence of fossa navicularis magna (FNM), canalis basilaris medianus (CBM), sphenoid emissary foramen (SEF), and/or Onodi cells (OC). Patterns of the SSP and sphenoid sinus mucosa dimensions (SSMD) were also recorded. Results: The prevalence of FNM, CBM, SEF, and OC was 26.0%, 22.4%, 47.4%, and 18.4%, respectively. Two hundred sixty-two (52.4%) sellartype SSP were defined, followed by post-sellar 191 (38.2%), pre-sellar 31 (6.2%), and conchal 16 (3.2%) types. The frequency of SSMD less than 1 mm, 1-3 mm, and greater than 3 mm was 40.6%, 38.4%, and 21.0%, respectively. An SEF was detected more frequently in females, while SSMD greater than 3 mm was more frequent in males. An FNM was more prevalent in the 18-29 and 30-39 age groups and SEF was significantly less frequent in patients over 60 years of age compared to other age groups. A sinus mucosa larger than 3 mm was more common in the younger than 18 year group. The frequency of post-sellar-type pneumatization was lower in patients younger than 18 years. Conclusion: Skull-base anomalies are common and may be detected incidentally during imaging procedures. The sphenoid sinus, its variations, and pneumatization patterns should also be taken into consideration in imaging procedures performed for various purposes.
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OBJECTIVE: Improper embryological development of the clivus, a bony structure that comprises part of the skull base, can lead to a clival canal defect. Previously thought to be a benign condition, clival canals have been reported to be associated with meningitis and meningoceles. In this review, the authors sought to present an unpublished case of a patient with a clival canal defect associated with meningitis and to evaluate all other reported cases. METHODS: In October 2020, a search of PubMed, Web of Science, and Scopus was conducted to identify all cases of clival canals reported from January 1, 1980, through October 31, 2020. RESULTS: Including the case presented herein, 13 cases of clival canals, 11 in children (84.6%) and 2 in adults (15.4%), have been identified. Of the pediatric patients, 5 (45.5%) had an associated meningocele, and 8 (72.7%) had meningitis. Nine of the 13 patients (69.2%) had defects that were treated surgically, 5 (38.5%) by a transnasal approach and 4 (30.8%) by a transoral approach. Two patients (15.4%) were treated with drainage and antibiotics, 1 patient (7.7%) was treated solely with antibiotics, and 1 patient (7.7%) was not treated. In the literature review, 8 reports of clival canals were found to be associated with meningitis, further contributing to the notion that the clival canal may be an overlooked source of recurrent infection. In several of these cases, surgical repair of the lesion was curative, thus preventing continued episodes of meningitis. CONCLUSIONS: When a patient has recurrent meningitis with no clear cause, taking a closer look at clival anatomy is recommended. In addition, if a clival canal defect has been identified, surgical repair should be considered a safe and effective primary treatment option.
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Meningitis , Meningocele , Adulto , Niño , Fosa Craneal Posterior/diagnóstico por imagen , Fosa Craneal Posterior/cirugía , Humanos , Meningitis/complicaciones , Meningitis/diagnóstico por imagen , Meningocele/complicaciones , Meningocele/diagnóstico por imagen , Meningocele/cirugía , Base del Cráneo , Resultado del TratamientoRESUMEN
PURPOSE: The clivus is a part of the sphenoid bone. It may show some anatomical variations such as fossa navicularis magna (FNM), canalis basilaris medianus (CBM) and craniopharyngeal canal (CPC). These variations have been associated with conditions like meningitis and tumors of skull base. Inadequate information about these structures may pose a risk of inaccurate diagnosis resulting in unwarranted interventional procedures. Hence, the knowledge about the prevalence of these variations is important. Thus, the objective of this study was to determine the prevalence of fossa navicularis magna, craniopharyngeal canal and canalis basilaris medianus and its types utilizing cone-beam computed tomography (CBCT) images. METHODS: Retrospectively, a total of 350 CBCT scans were evaluated for the presence of FNM, CBM, its types and CPC. The analysis was done by two observers independently. Cohen's kappa statistics was used to determine the interobserver agreement. RESULTS: FNM was noted in 19.4% cases, CBM in 9.7% cases, whereas CPC was not identified in any case. Type 5 was the most common type of CBM. There was no significant difference (p > 0.05) between genders and age groups for the prevalence and a highly significant (p < 0.01) substantial agreement between observers for the prevalence of FNM and highly significant (p < 0.01) moderate agreement for the prevalence of CBM and its types was obtained. CONCLUSION: FNM, CBM, CPC, albeit rare anatomical variations of clivus, knowledge of these structures is important for radiologists, anatomists and surgeons to avoid misdiagnosis and provide awareness to the individual of a higher possibility of meningitis or tumors of the skull base.
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Variación Anatómica , Fosa Craneal Posterior/anomalías , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Tomografía Computarizada de Haz Cónico/estadística & datos numéricos , Fosa Craneal Posterior/diagnóstico por imagen , Errores Diagnósticos/prevención & control , Femenino , Humanos , Masculino , Meningitis/diagnóstico , Meningitis/etiología , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Distribución por Sexo , Neoplasias de la Base del Cráneo/diagnóstico , Neoplasias de la Base del Cráneo/etiología , Hueso Esfenoides , Adulto JovenRESUMEN
PURPOSE: This study determined the prevalence of fossa navicularis magna (FNM), canalis basilaris medianus (CBM), and craniopharyngeal canal (CPC), the size of FNMs, and types of CBM using 3D computed tomography (CT) images. METHODS: A total of 1059 3D images [649 cone beam computed tomography (CBCT) and 410 CT] were evaluated in this study. The prevalence of FNM, CBM, and CPC, length, width, and depth of FNM, and type of CBM were assessed. RESULTS: Overall, FNM was identified in 7.6%, CPC in 0.3%, and CBM in 2.5% of the study group. Type 2 (0.1%) and Type 6 (0.1%) are the least common CBM types. There was no significant difference between genders for depth and width measurements (p > 0.05), however, the length of FNM was significantly higher in males than females in CBCT images (p = 0.02). CONCLUSION: FNM, CBM, and CPC are rare anatomical variants of clivus. However, they can facilitate spread of infection to the skull base or vice-versa. These types of anatomical variations should be known by radiologists to avoid unnecessary diagnosis and treatment procedures and to distinguish anatomic variations from pathological conditions.
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Fosa Craneal Posterior/anatomía & histología , Fosa Craneal Posterior/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Variación Anatómica , Niño , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Prevalencia , Tomografía Computarizada por Rayos XRESUMEN
The fossa navicularis is an anatomical variant of the skull base thought to be a rare finding. It represents a bony depression in the skull base. The authors here report the case of a fossa navicularis magna in a 9-year-old female who had been treated for recurrent episodes of meningitis.A literature review was also done to highlight the unique features and clinical importance of this distinctive radiological skull base finding. The literature search covered papers from the 19th century up to 2018. Earlier authors described "fossa navicularis" as a very rare skull base finding. So far, only three cases of fossa navicularis with associated clival or intracranial infection have been reported in the literature. This is the fourth reported case, and the defect was closed endoscopically via a transnasal route. This morphological skull base anomaly should be considered in the differential diagnoses for an unexplained skull base infective pathology.Skull base surgeons should be aware of the existence of the fossa navicularis because of its clinical importance in rendering a prompt diagnosis and appropriate treatment.