Examination of ethmoidal roof regarding Keros and Yenigun classifications in a Turkish population: a computerized tomography study.

PURPOSE: Understanding ethmoid roof morphology is crucial to prevent complications in endoscopic sinus surgery. This study aimed to evaluate the morphological properties of the ethmoidal roof regarding gender and age differences using Keros and Yenigun classifications on high-resolution computed tomography images. METHODS: We retrospectively analyzed 891 high-resolution computed tomography paranasal sinus study images and measured the depth of the cribriform plate in coronal sections and the anterior-posterior length in axial planes. The study retrospectively examined CT images of paranasal sinuses of patients living in the eastern Anatolian region of Turkey. RESULTS: In both Keros and Yenigun Classifications, the most common class was type 2, and the least common class was type 3. According to Keros et al.'s method, no significant difference was observed between men and women (p = 0.698). However, according to Yenigun et al., the average values of women in terms of the anterior-posterior distance of the ethmoid roof were significantly higher than men (p = 0.001). When examined according to age, a very low, negative correlation was revealed regarding Keros and Yenigun classifications (p = 0.047 and p < 0.001 retrospectively). According to Keros and Yenigun's classification, there was no significant difference between the left and right sides (p = 0.488 and p = 0.919, respectively). CONCLUSION: The morphological properties of the ethmoidal roof have importance to be considered for preoperative planning. Studying larger patient groups and meta-analyses that gather various research results about this subject might help better understand the ethmoidal roof morphology among populations.

Review of olfactory cleft roof anatomy.

Progress in skull-base endoscopic surgery has improved our knowledge of olfactory cleft (OC) anatomy. This article presents a review of current knowledge concerning the OC roof: descriptive anatomy, radiological exploration, and endoscopic observation. The OC is a narrow area in the most superior part of the nasal cavity. Its roof is the thinnest structure separating the nasal cavities from the brain; it comprises three superimposed tissues: nasal mucosa, ethmoid cribriform plate (ECP), and dura mater. The ECP comprises the anterior ECP containing the ethmoidal slit (ES) medially and the cribroethmoidal foramen (CEF) laterally; and the posterior ECP, comprising the olfactory foramina. The OC roof is bordered anteriorly by the nasal bone roof, laterally by the lateral ethmoid masses, and posteriorly by the jugum and anterior wall of the sphenoid sinuses. Imaging is crucial for analyzing this wall, providing precise detailed information on conformation and anatomic relations with adjacent structures such as the anterior ethmoidal artery. Understanding OC roof anatomy and correct interpretation of imaging are essential for safety in present-day functional endoscopic sinus surgery and anterior skull-base oncologic surgery.

Crista Galli Morphometry and Morphology: An Anatomical, Radiological, and Machine Learning Application Study / Crista Galli Morfometría y Morfología: Un Estudio de Aplicación Anatómica, Radiológica y de Aprendizaje Automático

SUMMARY: The study purposed to examine the morphometry and morphology of crista galli in cone beam computed tomography (CBCT) and apply a new analysis, supervised Machine Learning techniques to find the answers to research questions "Can sex be determined with crista galli morphometric measurements?" or "How effective are the crista galli morphometric measurements in determining sex?". Crista galli dimensions including anteroposterior, superoinferior, and laterolateral were measured and carried out on 200 healthy adult subjects (98 females; 102 males) aged between 18-79 years. Also, crista galli was classified with two methods called morphological types and Keros classification. In this study, the Chi-square test, Student's t-test, and Oneway ANOVA were performed. Additionally, Machine Learning techniques were applied. The means of the CGH, CGW, and CGL were found as 14.96 mm; 3.96 mm, and 12.76 mm in males, respectively. The same values were as 13.54 mm; 3.51 mm and 11.59±1.61 mm in females, respectively. The CG morphometric measurements of males were higher than those of females. There was a significant difference between sexes in terms of morphological classification type. Also, when the sex assignment of JRip was analyzed, out of 102 male instances 62 of them were correctly predicted, and for 98 female instances, 70 of them were correctly predicted according to their CG measurements. The JRip found the following classification rule for the given dataset: "if CGH<=14.4 then sex is female, otherwise sex is male". The accuracy of this rule is not high, but it gives an idea about the relationship between CG measurements and sex. Although the issue that CG morphometric measurements can be used in sex determination is still controversial, it was concluded in the analysis that CG morphometric measurements can be used in sex determination. Also, Machine Learning Techniques give an idea about the relationship between CG measurements and sex.

En el estudio se propuso examinar la morfometría y la morfología de la crista galli del hueso etmoides usando tomografía computarizada de haz cónico (CBCT) y aplicar un nuevo análisis, técnicas de aprendizaje automático supervisado para encontrar las respuestas a las preguntas de investigación "¿Se puede determinar el sexo con mediciones morfométricas de la crista galli?" o "¿Qué tan efectivas son las medidas morfométricas de la crista galli para determinar el sexo?". Las dimensiones de la crista galli, incluidas los diámetros anteroposterior, superoinferior y laterolateral, se midieron y realizaron en 200 sujetos adultos sanos (98 mujeres; 102 hombres) con edades comprendidas entre los 18 y los 79 años. La crista galli se clasificó con dos métodos llamados tipos morfológicos y clasificación de Keros. En este estudio, se realizaron la prueba de Chicuadrado, la prueba t de Student y ANOVA de una vía. Adicionalmente, se aplicaron técnicas de Machine Learning. Las medias de CGH, CGW y CGL se encontraron en 14,96 mm; 3,96 mm y 12,76 mm en hombres, respectivamente. Los mismos valores fueron 13,54 mm; 3,51 mm y 11,59 ± 1,61 mm en mujeres, respectivamente. Las medidas morfométricas del CG de los hombress fueron más altas que las de las mujeres. Hubo una diferencia significativa entre sexos en cuanto al tipo de clasificación morfológica. Además, cuando se analizó la asignación de sexo de JRip, de 102 instancias masculinas, 62 de ellas se predijeron correctamente, y de 98 instancias femeninas, 70 de ellas se predijeron correctamente de acuerdo con las mediciones de CG. El JRip encontró la siguiente regla de clasificación para el conjunto de datos dado: "si CGH<=14.4, por tanto el sexo es femenino, de lo contrario, el sexo es masculino". La precisión de esta regla no es alta, pero da una idea de la relación entre las medidas del CG y el sexo. Aunque la pregunta si las medidas morfométricas CG se pueden usar en la determinación del sexo sigue aún siendo controvertida. Se concluyó en el análisis que las medidas morfométricas CG se pueden usar en la determinación del sexo. Además, las técnicas de aprendizaje automático dan una idea de la relación entre las medidas de CG y el sexo.

A comparative analysis of the CP and CG using 2D and 3D visualisation approaches.

Investigations on the structural variations in the cribriform plate (CP), olfactory foramina and the Crista Galli showcase the benefits of using 3D imaging on smaller structures. These techniques reveal accurate details about bone morphology and density. Comparing different techniques, this project aims to examine the correlation between the CP, olfactory foramina, and Crista Galli. Computed tomography was used to translate and apply the findings acquired from the samples in radiographic studies on CPs for potential clinical significance. The findings show that the surface area measurements were significantly larger when using 3D imaging techniques in comparison with the 2D counterpart. Using 2D imaging, the maximum surface area of the CPs was 239.54 mm2, however, paired 3D samples showed the maximum surface area was 355.51 mm2. The findings show that Crista Galli's dimensions varied greatly, with length ranging from 15 to 26 mm, height ranging from 5 to 18 mm, and width ranging from 2 to 7 mm. The 3D imaging allowed for surface area measurements on the Crista Galli, and the surface area ranged from 130 to 390 mm2. When 3D imaging was used, significant correlations were found between the surface area of the CP and the length of the Crista Galli (p = 0.001). The findings show that measurements on the Crista Galli using 2D and 3D reconstructed radiographic imaging reflect similar ranges of dimensions to 3D imaging measurements. The findings also suggest that the Crista Galli may increase in length with the CP to support the latter and olfactory bulb during trauma which may be used by clinicians alongside 2D CT scans for optimal diagnosis.

Strategies of vascularization of the ethmoid labyrinth in selected even-toed ungulates (Artiodactyla) and carnivores (Carnivora).

The anatomy of the nasal cavity and its structures, as well as other elements building a scaffold for olfactory organs, differs significantly among various groups of mammals. Understanding anatomical conditions of quality of olfaction are being studied worldwide and is a complex problem. Among many studies regarding bone and epithelial structures of turbinates and connected anatomical structures, few studies describe the vascularization of turbinates. Ethmoid turbinates are above all covered in olfactory epithelium containing branched axons that receive olfactory stimuli and as olfactory nerves penetrate the cribriform lamina of the ethmoid bone conveying information from smell receptors to the brain. Differences in vascularization of the cribriform plate and turbinates may add crucial information complementing studies regarding the olfactory organ's bone and soft tissue structures. In the study, we describe the vascularization of the cribriform plate of the ethmoid bone of 54 Artiodactyla and Carnivora.

Accessory anterior ethmoidal nerve and artery: a cadaveric case report.

The anterior ethmoidal artery (AEA) is an important surgical landmark for procedures involving the anterior cranial fossa. Many variations in the location and branching pattern of the AEA have been reported throughout the literature. These anatomical variations are important for surgeons to be familiar with as injury to the AEA can lead to massive haemorrhage, orbital haematomas, and cerebrospinal fluid rhinorrhoea. Anatomical landmarks such as the ethmoidal foramen can be used to identify the location of the AEA; however, it is also important to consider that the foramen may have variable presentations. If there is ever difficulty with identification of the AEA, surgeons should pursue a high-resolution computed tomography to minimise the risk of surgical complications. In this report, we present a rare case of a variant accessory anterior ethmoidal artery and nerve, and variations in the ethmoidal foramen found during cadaveric dissection.

Anterior ethmoid and frontal sinus drainage pathways: five patterns formed and defined by their bony walls.

PURPOSE: To perform endoscopic sinus surgery safely and effectively, surgeons need to visualize the complex anatomy of the anterior ethmoid and frontal sinus region. Because this anatomy is so variable and individualized, the foundation of understanding lies in identifying, following, and visualizing the drainage pathway patterns and anticipating possible variations. METHODS: We studied 100 sides (50 cases: 22 male, 28 female, aged 12-86, average age 46.5 years, ± 19.5) using computed tomography (CT) and multiplanar reconstruction (MPR) to identify and classify the drainage pathways leading to the frontal sinus and anterior ethmoidal cells. RESULTS: Analysis revealed five patterns of drainage pathways defined by their bony walls: between the uncinate process and the lamina papyracea [UP-LP]; between the uncinate process and the middle turbinate [UP-MT]; between the uncinate process and the accessory uncinate process [UP-UPa]; between the uncinate process and the basal lamella of the ethmoidal bulla [UP-BLEB]; and between the basal lamella of the ethmoidal bulla and the basal lamella of the middle turbinate [BLEB-BLMT]. In most cases, BLEB formed the posterior wall of the drainage pathway of the frontal sinus, indicating BLEB could be one of the most important landmarks for approaching the frontal sinus. CONCLUSIONS: As endoscopic sinus surgery depends on an understanding of this anatomy, this study may help surgeons to identify and follow the drainage pathways more accurately and safely through the anterior ethmoid to the frontal sinus.

Sex estimation with morphometric and morphological characteristics of the crista galli.

PURPOSE: The purpose of the present study was to analyze the dimensions of the crista galli (CG) in preserved skulls, and to examine the role of the morphometry and morphology of the CG on the sex estimation. METHODS: Anteroposterior, superoinferior, and laterolateral diameters of the CG were measured of 207 preserved adult skulls of Anatolia origin with known sex (108 males, 99 females) in the Anatolian population. CG were morphologically classified into three types according to the dimensions. The success of CG dimensions in sex determination was evaluated with ROC analysis, and univariate and multivariate binary logistic regression analysis. The relationship between morphological types of the CG and sex was analyzed with the Chi-square test. RESULTS: The anteroposterior and superoinferior diameters of the CG significantly were longer in males than females while the laterolateral diameter of the CG was wider in females (p < 0.001). Superoposterior diameter (88.4%) of the CG showed higher sex classification accuracy for sex estimation compared to the laterolateral (82.6%) and anteroposterior diameters (80.6%). When all three parameters were used together, the sex classification accuracy rate was 94.2%. The presence of ossified and tubular types of CG identified the male sex with 85% and 74.6% accuracy rates, respectively while teardrop type CG identified female sex with a 72.2% accuracy rate. CONCLUSION: CG exhibits sexual dimorphism both morphometrically and morphologically. The height, length, and width measurements and the morphological types of CG can be used in sex determination directly from the skull with high accuracy rates.

A computed tomography study on the olfactory fossa in dried skulls.

PURPOSE: The computed tomography (CT) study investigates the olfactory fossa (OF) morphometry and morphology. METHODS: Fifty Greek adult dried skulls were macroscopically investigated for the detection of the OF morphological patterns and after a multiplanar CT reconstruction, the OF morphometry was accurately calculated using a digital ruler. RESULTS: Types I and II surface contour patterns were the most frequently identified (36 and 32%), followed by types III, IV, and V (16, 12, and 4%). Crista galli mean length, height, and width were 19.46 ± 2.34 mm, 12.69 ± 2.7 mm, and 5.18 ± 1.11 mm. The OF mean maximum length was 22.29 ± 2.16 mm on the right and 22.10 ± 2.44 mm on the left side, and symmetry was detected. The OF median values of the maximum depth for its anterior, middle, and posterior third were 4.91 mm, 4.72 mm, and 2.78 mm on the right and 4.55 mm, 4.75 mm, and 2.55 mm on the left side. Symmetry was observed in any third of the OF. The OF median values of the surface maximum width for the anterior, middle, and posterior thirds were 9.29 mm, 11.48 mm, and 13.07 mm. A significant gradual increase of the OF surface maximum width was detected in the anteroposterior direction in the total sample (p < 0.001), with the highest value (23.12 mm) in the posterior third. A significant (p < 0.001) very strong (rs = -0.798) and a moderate (rs = -0.524) negative linear correlation in the OF anterior and middle third were, respectively, identified between its maximum depth and width. No gender impact was identified. CONCLUSIONS: The study helps to familiarize with the calculation of the OF dimensions and simplifies the understanding of its complex anatomy, to reach successful surgical planning and minimize perioperative complications.

Nasosinusal Endoscopic Anatomy and Physiology

The present article focuses on the analysis of the nasal cavity's anatomy succinctly and descriptively. This essay was carried out through a bibliographic review, directed to the detailed anatomy of the nasal cavity, and the structures that form its sinuses. We have identified the need formore studies directed to the related anatomical area so that the improved knowledge of this region ensures a nasoendoscopic treatment with better effectiveness and no complications.

Patterns of Pneumatization of the Posterior Nasal Roof.

(1) Background: For good surgical performance, sound knowledge of anatomy is required. Although the ethmoid air cells and sphenoid sinuses are subject to a high degree of variation, their possible extensions above the nasal fossa at the posterior end of the cribriform plate of the ethmoid bone (CPEB) were seemingly overlooked. (2) Methods: We retrospectively studied 162 case files from 55 male and 107 female cases, with ages varying from 42 to 80, which were scanned using Cone Beam Computed Tomography. (3) Results: In 56.17% of cases, an unpneumatized CPEB (type I) was found. Nasal roof recesses of ethmoidal origin (type II) were found at the posterior end of the CPEB in 20.37% of cases. Different types of sphenoidal pneumatizations of the posterior end of the CPEB (type III) were found in 22.83% of the cases. Onodi cells projected nasal roof recesses (type IV) in only 10 cases. In all types, nasal roof recesses were found either above the CPEB or within/underneath it. Moreover, such nasal roof recesses were found to be either unilateral, extended contralaterally, or bilateral. (4) Conclusions: As such recesses of the posterior CPEB, previously overlooked, belong to the posterior rhinobase, they should be carefully documented preoperatively to avoid unwanted surgical damage to the olfactory bulb or CSF fistula.

Anatomical Study of Ethmoidal Foramina and Optic Canal in Endoscopic Trans-Nasal Approach to Anterior Skull Base.

BACKGROUND: Surgery to anterior skull base is challenging since complex structures are involved. Injury of olfactory fila and optic nerve may result in postoperative complications. In our study, the authors aim to use computer topographic image to provide a comprehensive anatomical information of anterior skull base and set up a new classification of optic canal (OC) in ethmoid sinus by the degree of bony defect, so as to help surgeons in endoscopic transnasal approach to anterior skull base. METHOD: Computer topographic angiography images of 112 individuals were reviewed, the measurement was performed on coronal, sagittal, and axis planes after the multiplanar reformation. Nostril and mid-sagittal lines were used to locate the anterior, middle, and posterior part of ethmoidal foramina and orbital opening of OC. Further, the authors classified OC in ethmoidal sinus into 4 types by the degree of the bony defect. RESULT: Distance between nostril to anterior, middle, and posterior part of ethmoidal foramina and OC are 6.23 ± 0.21, 6.62 ±â€Š0.26, 7.29 ±â€Š0.25, and 7.76 ±â€Š0.41 mm, respectively. Angle between line from nostril to ethmoidal foramina and horizontal plane are 47.50°â€Š±â€Š1.03°, 41.67°â€Š±â€Š1.33°, 37.20°â€Š±â€Š1.34°, respectively. For the 4 types of OC, the percentage is 15.6%, 11.6%, 31.3%, and 41.5%, respectively. CONCLUSIONS: Our findings provide anatomical information of ethmoidal foramina and OC during endoscopic transnasal approach to anterior skull base, on the basis of some fixed anatomical landmarks. So as to enhance the surgical safety of this procedure and aid in the choice of the appropriate endoscopic equipment for the procedure.

Ambiguous "olfactory" terms for anatomic spaces adjacent to the cribriform plate: A publication database analysis and quest for uniformity.

A precise nomenclature and terminology is the foundation of communication in Anatomy and related biomedical sciences. The olfactory bulbs and nerves lie above and below the cribriform plate (CP), respectively. Hence, many anatomical landmarks in this region have names adopting the term "olfactory" as qualifiers. Ambiguous use of these "olfactory" terms exists, with some potential repercussions on patient treatments. We performed a publication database analysis to determine the frequency of misuse of names for seven anatomical "olfactory" spaces close to the CP and nasal cavity. We searched PubMed® publications having the keyword "olfactory" in their title or abstract, plus one of seven other keywords: "groove", "fossa", "recess", "cleft", "vestibule", "sulcus", and "cistern". We reviewed all abstracts for accuracy of these terms relative to accepted norms or customary definitions. By February 2020, we found all these keywords in 1255 articles. For the terms olfactory "groove" and "fossa", the number of relevant articles (and percentage of those inaccurately using these terms) were 374 (1.1%), and 49 (8.2%), respectively. All 52 abstracts containing "olfactory" and "vestibule" were irrelevant, relating to the "nasal vestibule" and olfactory function, instead of "olfactory vestibule". Overall, terms used to describe "olfactory" spaces near the CP are seldom ambiguous or inaccurate, but the terms olfactory "groove" and "fossa" are occasionally misused, We propose several new "olfactory" terms for inclusion in the Terminologia Anatomica, and stress the need for uniform nomenclature leading to greater consistency and accuracy in clinical use of anatomical terms containing the word "olfactory" as a descriptor.

[Proposal for the delineation of postoperative primary clinical target volumes in ethmoid cancers]. / Proposition de délinéation des volumes cibles anatomocliniques postopératoires de la tumeur primitive des cancers de l'ethmoïde.

It is proposed to delineate the anatomo-clinical target volumes of primary tumor (CTV-P) in ethmoid cancers treated with post-operative radiotherapy. This concept is based on the use of radioanatomy and the natural history of cancer. It is supported by the repositioning of the planning scanner with preoperative imaging for the replacement of the initial GTV and the creation of margins around it extended to the microscopic risk zones according to the anatomical concept. This article does not discuss the indications of external radiotherapy but specifies the volumes to be delineated if radiotherapy is considered.

The Relationship of High Septal Deviation, the Depth of Olfactory Fossa, and Gera Angle: Is High Septal Deviation Associated With Any Anatomic Abnormalities in the Anterior Skull Base?

OBJECTIVE: To investigate the association of high septal deviation with the olfactory fossa depth and Gera angle. METHODS: Fifty-four computed tomography scans of patients with high septal deviation were evaluated. The olfactory fossa depth and Gera angle were measured. The values of the deviated and nondeviated sides were compared. RESULTS: No association between high septal deviation and the olfactory fossa depth and Gera angle was found. CONCLUSION: High septal deviation does not affect the olfactory fossa depth and Gera angle. In other words, the olfactory fossa depth and Gera angle have no association with the high septal deviation.

The impact of extreme skull morphology in domestic dogs on cribriform plate shape.

Dog owners are often impressed by their dog's sense of smell. Many of these dogs, however, have skulls that are quite altered from those of their closest canid relatives. Housed within these skulls are essential olfactory structures like the cribriform plate that play a role in olfaction and the transmission of olfactory nerve impulses to the olfactory bulb of the brain. With improvements in CT technology and accessibility, we are now able to digitally reconstruct in 3D cribriform plate morphology and study its variation within and among species. In this study, we CT scanned the skulls of 95 dog specimens from 45 different domestic dog breeds and 12 species of wild canid and compared the shape of the cribriform plate among three main groups: domestic dog breeds, wolf-like canids, and fox-like canids. Despite only recent selective pressure for extreme skull morphology, domestic dogs display much more variation in cribriform plate shape than wild canids, indicating that cribriform plate shape is plastic and linked to skull shape. Intense artificial selection on domestic dog skull phenotype in the last 200 years has clear effects on secondary features of the domestic dog skull, implying that selection for overt phenotypes also can impact other anatomical features associated with the skull, like the cribriform plate.

Anatomical Factors that Can Predict the Structure of Lamina Papyracea for Endoscopic Sinus Surgery.

OBJECTIVES: This study investigated morphological variations of lamina papyracea, the structure that should be carefully considered when opening posterior ethmoid sinus during endoscopic sinus surgery, to avoid injury. STUDY DESIGN: This study employed axial, coronal, and sagittal computed tomography. METHODS: Using computed tomography images of 228 face-sides, various anatomical parameters were determined: distances of the anterior and posterior ethmoid arteries from the skull base, and from the third lamella; changes in the angles of the lamina papyracea at the anterior and posterior ethmoid sinuses; and presence or absence of supraorbital ethmoid cell (SECs), Onodi cell, and Haller cell. The relationship between the distances which indicate the point of maximum projection by the lamina papyracea among third lamina and posterior ethmoid artery into the posterior ethmoid sinus and these anatomical factors were analyzed statistically. RESULTS: The projection distance of lamina papyracea into the posterior ethmoid sinus was -2.6 mm to 3.4 mm, and in 41.2% of cases, projection in the direction of the nasal cavity was greater than that of the lamina papyracea at the anterior ethmoid sinus. This distance increased with increasing distance of the maximum projection point from the skull base and increasing floating distances of the anterior and posterior ethmoid arteries. The number of subjects with large projection distances was increased among those with floating posterior ethmoid arteries. In addition, subjects with SECs had significantly greater projection distances. CONCLUSIONS: Particular care should be taken to avoid injury to the lamina papyracea when opening the posterior ethmoid sinus in subjects with floating anterior or posterior ethmoid arteries, and/or SEC. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E19-E25, 2021.

Domesticating olfaction: Dog breeds, including scent hounds, have reduced cribriform plate morphology relative to wolves.

The domestic dog is assumed by nearly everyone to be the consummate smeller. Within the species Canis familiaris individual breeds, such as the bloodhound or beagle, are known as olfactory stars. These are "scent breeds," a grouping variably defined as a genetic clade or breed class commonly used for scent detection tasks. Previous work suggests that the dog has a more robust olfactory anatomy than many mammal species. Now we undertake a closer investigation of the dog's olfactory system, both in relationship to its closest wild relatives, the wolf and coyote, and across individual breeds. First, we seek to resolve whether the dog has lost olfactory capacity through its domestication from the wolf lineage. Second, we test the inertial lore that among dogs, "scent breeds," have a superior olfactory facility. As a measure of relative olfactory capacity, we look to the cribriform plate (CP), a bony cup in the posterior nasal cavity perforated by passageways for all olfactory nerve bundles streaming from the periphery to the brain. Using high-resolution computed tomography (CT) scans and digital quantification, we compare relative CP size in 46 dog breeds, the coyote and gray wolf. Results show the dog has a reduced CP surface area relative to the wolf and coyote. Moreover, we found no significant differences between CP size of "scent" and "non-scent" breeds. Our study suggests that the dog lost olfactory capacity as a result of domestication and this loss was not recovered in particular breed groupings through directed artificial selection for increased olfactory facility.

Classification of crista galli pneumatization and clinical considerations for anterior skull base surgery.

Cerebrospinal fluid (CSF) leakage caused by frontal sinus exposure is a serious complication in the basal interhemispheric approach (BIHA). Crista galli pneumatization (CGP) is often observed on preoperative computed tomography (CT) scan. The aim of this study was to classify and describe variations in anatomical measurements of CGP. We examined CT images of 300 patients with brain tumors to assess the morphology and incidence of CGP. Crista galli were classified according to their location relative to the cribriform plate and the presence of pneumatization. The paranasal sinuses were investigated as the origin of CGP. We assessed 24 patients using the BIHA for skull base tumors; these patients were included as clinical cases to assess the range of skeletonization of the crista galli and determine the route of CSF leakage in the other 276 patients. CGP was found in 28/300 CT scans, including upper, middle, and lower type CGPs. The origin of CGPs was the frontal sinus or ethmoid sinus. All CGPs were localized in the anterior half of the crista galli. In the 24 consecutive clinical cases, there were 13 tuberculum sellae meningiomas, 3 craniopharyngiomas, and 8 with other pathologies. The preoperative crista galli height was 12.3 mm and the distance from the top of the skeletonization to the cribriform plate was 5.2 mm. CGP originating from the paranasal sinuses can lead to CSF leakage. In cases where CGP originates from the ethmoid sinus, care should be taken to seal the exposed crista galli intradurally.

Impact of the ethmoid volume on endoscopic medial wall decompression outcomes in Graves' orbitopathy.

BACKGROUND: Endoscopic orbital decompression is a well-established technique for Graves orbitopathy treatment. AIMS: Measurement of the ethmoid volume and its correlation with proptosis reduction in patients undergoing endoscopic orbital decompression for Graves' orbitopathy. METHODS: We retrospectively reviewed clinical charts of 209 patients (319 orbits) operated by a surgeon at our institution between 1998 and 2019. RESULTS: Average age was 46.9 years. About 83.3% of the patients were female, 54.6% were smokers, 93.8% were euthyroid at the time of decompression, 3.8% were hypothyroid and 2.4% were hyperthyroid. About 77.5% of the patients underwent bilateral surgery, the remainder and unilateral. Subsequent stages included strabismus surgery in 22.5% patients, Müllerectomy 37.8%, with or without canthoplasty (14.8 vs. 23%). Mean proptosis reduction was 4.61 mm. Mean ethmoid volume was 5.57 mm3. Ethmoid volume had a moderate positive correlation with proptosis reduction (r s = 0.49, p < .001). Further investigation, statistically significant moderate correlation was found only in the small (SE) and big (BE) ethmoid groups. CONCLUSION: We advise evaluating ethmoid sinus pneumatization on computed tomography before decompression to estimate possible anatomical limitations. Additional wall decompression might be advocated in most severe cases.