Anatomographic Variants of Sphenoid Sinus in Ethiopian Population

Comparison of sphenoid sinus variations and morphometric values in dolichocephalic and hyperbrachycephalic individuals

BackgroundThe internal carotid artery, optic, maxillary, and vidian nerves are important anatomical structures adjacent to the sphenoid sinus. In some individuals, these structures may protrude into the sinus, and this condition is important in surgical procedures.PurposeTo investigate the morphometric variations and anatomical differences in the sphenoid sinus and surrounding structures between dolichocephalic and hyperbrachycephalic skull types using computed tomography (CT).Material and MethodsCT images of dolichocephalic (n = 50), hyperbrachycephalic (n = 64), and mesocephalic (n = 52) individuals were used in the study. Sphenoid sinus position, dimensions, septum types, and protrusion and dehiscence for the carotid canal and optic canal, maxillary, and vidian nerves were evaluated. For statistical evaluation, the Mann-Whitney U-test, Kruskal-Wallis test, Pearson chi-square, Fisher's exact test, and Spearman's rho correlation were used in the study.ResultsThe difference between all skull types was found to be significant in the rates of protrusion and dehiscence in the carotid canal and the maxillary nerve and the difference between sphenoid sinus heights in two different skull types (dolichocephalic and hyperbrachycephalic) was also significant (P < 0.05). In septum typing, seven different septum types were detected. The most common sphenoid sinus position was postsellar in all skull types.ConclusionDifferences in the frequency of protrusion and dehiscence for the carotid canal and maxillary nerve in dolichocephalic, hyperbrachycephalic, and mesocephalic individuals reveal that the skull types of individuals are important in studies on the sphenoid sinus.

Evaluation of the Frequency of Anatomic Variations of the Paranasal Sinus Region by Using Multidetector Computed Tomography: A Hospital-Based Cross-Sectional Study

Background and Aims

The sinus anatomy should be well-understood by the sinus surgeons to carry out functional endoscopic sinus surgery carefully. That's why CT scans are vital to provide essential clarity and accuracy for comprehensive presurgical planning with minimal risks. The aim of this study was to evaluate the frequency of anatomic variations of the paranasal sinus region by using multidetector computed tomography.

Methods

A cross-sectional study of one hundred and fifty-three patients of all age groups was carried out in the radiology department of Shalamar Hospital Lahore from 20 January, 2024 to 10 April, 2024 to evaluate anatomical variations presented to the facility by using multidetector CT. Data were collected using a standardized data collection sheet and analyzed using SPSS version 25.0.

Results

The study included 94 males and 59 females with a median age of 43.9 years. Among the study population, 4.6% had aplasia of the frontal sinus, 84.3% had bilateral frontal sinus, but 13.7% had unilateral, 42.5% had more than 2 chambers of frontal sinus, and 9.8% had hypoplasia with persistent metopic suture. Four patterns of sphenoid sinus pneumatization were recognized: the conchal, the presellar, the sellar, and the post-sellar, with prevalence rates of 2.0%, 11.1%, 28.1%, and 56.9%, respectively. 0.7% had hypoplasia of maxillary sinus, 9.2% had exostoses, 13.7% had extension of teeth roots to maxillary sinus, and 3.3% had maxillary sinus septations. Ethmoidal bulla, Agger nasi cells, and Haller cells had frequencies of 49%, 32.7%, and 30.7%, respectively.

Conclusions

The most common anatomical variations are bilateral frontal sinus, post-sellar pneumatization of sphenoid sinus, ethmoidal bulla in ethmoid sinus, and extension of teeth roots to maxillary sinus. Such characteristics and findings are to be evaluated for the management of pathologies associated with these variations and consequent surgical interventions.

Surgical-related Morphological Characteristics of Sphenoid Sinuses: A Comprehensive CT-Based Analysis

Background

This study aims to assess the relationships between sphenoid sinus (SS) types, septation, lobulation, symmetry, septal deviation, and the variations in SS pneumatization regarding the surrounding neurovascular structures using Computed tomography (CT) images. Sexes and age groups were investigated.

Material and Methods

We retrospectively evaluated head CT-scans of 320 patients (age range 18-49 years); mean of 43.13 ± 17.39 to evaluate the morphological characteristics of the SS (Symmetry, Pneumatization, Extension, Septation, Lobulation, Internal Carotid, and Optic Nerve). Analyses were performed using SPSS version 20.0 (IBM Corporation, Armonk, NY, USA), with a 95% confidence level.

Results

Our findings revealed an incidence of anatomographical variations in terms of pneumatization that varied between 0.3% (conchal)-60% (postsellar). These variants include 72.5% subdorsal extension, 92.2% lobular extension. Septations either presented as complete septa (90.9%) which extend from the anterior to the posterior wall dividing the sinus into different antra or as incomplete accessory septa. We also demonstrated anatomographic variants in terms of Internal Carotid (ICA), and Optic Nerve (ON). As sphenoid sinuses pneumatize more, the frequency of optic nerve (ON) and internal carotid artery (ICA) protrusion and wall dehiscence into the sinus increases.

Conclusions

Results show that anatomic variations and pneumatization of the paranasal sinuses holds significant importance in diagnosing and understanding sinus pathologies The findings underscore a potential correlation between the anatomical variants of the SS and the presence of population group variability. Key words:Sphenoid sinus, CT scan, •Sellar type, Internal carotid artery, Optic nerve.

Anatomical Features and Morphometric Characteristics of the Sphenoidal Sinus in MRI Studies

Differential access to pathological sellar processes and adjacent regions is determined by the anatomic structures identified through diagnostic imaging. Both direct endonasal access (microscopic or endoscopic) and sublabial access utilize the sphenoid sinus (SS) as the primary surgical pathway. Critical factors include the pneumatization of the sinus, its intermediate septa, and the presence of a double wall, consisting of a connective tissue membrane along the dorsal wall of the SS. The present study aims to demonstrate the significance of the size and type of the SS based on MRI measurements. The type of SS, its pneumatization, and the proximity of adjacent brain structures are crucial for different surgical approaches to the SS and pituitary fossa. In neurosurgical practice, six main types of sinuses are recognized: sphenoid body type, lateral type, clival type, lesser wing type, anterior type, and combined type. Failure to consider these variations can lead to damage to the cavernous sinus, Meckel's cave, nerve structures in the middle cranial fossa, planum sphenoidale, suprasellar region, and vital brainstem structures located on the clivus. Randomly included MRI measurements were conducted on 112 patients from Pulmed University Hospital, Plovdiv, Bulgaria, categorized into two cohorts based on gender, with mean ages of 51 years for men and 47.8 years for women. The measurements, recorded in centimeters, were obtained using two imaging software programs, RadiAnt DICOM Viewer (Medixant, Poznan, Poland) and Weasis DICOM Viewer (Nicolas Roduit, https://github.com/nroduit/Weasis). No statistically significant differences were observed between the measurements produced by the two programs. Measurements of the SS were taken in two equal groups, using three different projections: axial, sagittal, and coronal. The results for height, width, and depth showed average sizes of 2.73-3.04 cm in axial projections, 1.70-2.64 cm in sagittal projections, and 2.86-3.03 cm in coronal projections. The minor differences between axial and coronal measurements of the same parameters (height and width) are statistically acceptable and attributed to the varying angles of the MRI scans. These measurements are crucial for planning surgical access to the sellar and parasellar regions, determining the necessary bony resection of the posterior wall of the SS, and preventing complications from excessive bony trepanation.

Computed tomography based evaluation of the association between sphenoid sinus pneumatization patterns and variations of adjacent bony structures in relation to age and gender

Many studies revealed that the sphenoid sinus pneumatization (SSP) affects the protrusion/dehiscence of adjacent structures including optic canal (OC), foramen rotundum (FR), vidian canal (VC), and carotid canal (CC). Knowledge of this relationship bears vital importance to identify the safest surgical route during transsphenoidal procedures. Therefore, we aimed to determine the individualized prevalence of the protrusion/dehiscence of adjacent structures based on sagittal and coronal SSP (SSSP and CSSP) patterns. Computed tomography images of 300 patients were analysed to identify the SSSP and CSSP types, and the protrusion/dehiscence of adjacent structures was determined. The relationship between the variables was examined using statistical analysis in terms of age, gender, and laterality. The most prevalent SSSP type was postsellar (62.7%), followed by sellar (30%), presellar (6.6%), and conchal (0.7%). In 71.3% of patients, five types of CSSP were observed, with 23.6% and 21.7% exhibiting Type IV and V, respectively. Our results indicated that postsellar type, Type IV and V CSSP associated with the highest likelihood of protrusion/dehiscence of OC, FR, VC, and CC. Furthermore, no significant correlation was observed between these qualitative variables and gender, with the exception of the VC dehiscence, the protrusion of OC and CC. No notable differences were identified with respect to laterality. Also, the probability of having postsellar type, Type IV and V CSSP, as well as the protrusion of OC, VC, and CC, decreased with increasing age. Further detailed analysis of this association is required to predict the size of the surgical window and to prevent neurovascular injury.

Evaluation of the relationship between sphenoid sinus morphology and area and volume by computed tomography

OBJECTIVES

The aim of this study is to investigate the effect of sphenoid sinus pneumatization types, Onodi cell (OC), internal carotid artery (ICA), optic nerve (ON) on sinus volume and area on computed tomography (CT) images.

METHODS

The CT images of 150 patients were evaluated. Sphenoid sinus pneumatization types, OC prevalence, protrusion and dehiscence of ICA and ON, the volume and area were evaluated.

RESULTS

The sinus volume and area were statistically higher in patients with bilateral protrusion of ICA and ON then patients without protrusion of ICA and ON. The mean volume and area of sinus were 9949.4 ± 351.0 mm3 and 4570.9 ± 1604.9 mm2, respectively. The volume and area of sphenoid sinus did not differ significantly between groups with and without OC. The postsellar b type sphenoid sinus had the highest volume, while conchal type has the least volume.

CONCLUSIONS

Bilateral protrusion and dehiscence of ICA and bilateral protrusion of ON caused a significant increase in the sphenoid sinus volume and area. The presence of ICA and ON, the pneumatization of the sinus is an anatomical structure that can affect the sinus volume and area. Before the operation, three-dimensional evaluation should be performed to determine whether these structures are bilateral/unilateral and it should be remembered that the sinus volume and area can change.

Computed tomography-based assessment of sphenoid sinus and sella turcica pneumatization analysis: a retrospective study

Background

A preoperative three-dimensional examination of the sphenoid sinus anatomy, its pneumatization pattern, and its relevance to neighboring neurovascular constructions is crucial to preventing possible complications. In this study, the aim was to evaluate the relationship between sphenoid sinus pneumatization types and the sella turcica using computed tomography (CT).

Methods

CT data from 420 patients referred to the Department of Dentomaxillofacial Radiology were evaluated retrospectively. Sella pneumatization types were classified as conchal, presellar, incomplete sellar, and complete sellar, and they were evaluated. Obtained data were evaluated using the IBM SPSS 25.0 (Armonk, New York, USA) package program.

Results

CT images of 420 individuals, including 174 women and 246 men with a mean age of 43.87 ± 17.58 years, were included in the study. When the sella turcica morphologies were evaluated, the most widespread morphological type was irregularity in the posterior part of the dorsum sella, in 51.2% of cases. In addition, a statistically significant correlation was found between the pneumatization of the sphenoid sinus and the morphological types of sella (p < 0.05).

Conclusion

In this research endeavor, the predominant observation comprised the complete sellar sphenoid sinus pneumatization type, exhibiting irregularity in the posterior aspect of the dorsum sella, representing one of the sellar types. Notwithstanding, it is imperative to conduct additional investigations to establish the generalizability of the present study's findings.

Radiological anatomical variations of the lateral nasal wall and anterior skull base amongst different populations: A systematic review and meta-analysis

OBJECTIVES

To determine the anatomical variations of the lateral nasal wall and anterior skull base amongst populations in different geographical regions.

DESIGN

Systematic review and meta-analysis.

METHODS

Using PRISMA guidelines, SCOPUS and PUBMED databases were searched from inception until 1 March 2022. The regions and populations identified were from Europe, Asia, Middle East, Australia-New Zealand-Oceania, South America, North America and Africa. Random-effects model was used to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic and Cochran's Q test.

MAIN OUTCOME MEASURES

Anatomical variations of the lateral nasal wall and anterior skull base confirmed by computed tomography scan.

RESULTS

Fifty-six articles were included with a total of 11 805 persons. The most common anatomical variation of the ostiomeatal complex was pneumatization of the agger nasi (84.1%), olfactory fossa was Keros type 2 (53.8%) and ethmoids was asymmetry of the roof (42.8%). Sphenoethmoidal and suprabullar cells have a higher prevalence in North Americans (53.7%, 95% CI: 46.00-61.33) while asymmetry of ethmoid roof more common in Middle Easterns (85.5%, 95% CI: .00-100). Bent uncinate process has greater prevalence in Asians while supraorbital ethmoid cells and Keros type 3 more common in non-Asians. The overall studies have substantial heterogeneity and publication bias.

CONCLUSION

Certain anatomic variants are more common in a specific population. The 'approach of analysis' plays a role in the prevalence estimates and consensus should be made in future studies regarding the most appropriate 'approach of analysis' either by persons or by sides.

Evaluation of paranasal anatomical variations with multidetector CT in Turkish population

Abstract.

Lost or fragmented bony septum of the optic canal facing the sphenoid sinus: a histological study using elderly donated cadavers

PURPOSE

To histologically describe a direct contact (the so-called dehiscence) of the optic nerve (ON) and/or internal carotid artery (ICA) to the mucosa of posterior paranasal sinuses represented by the sphenoid sinus (SS).

METHODS

Observations of histological sections of unilateral or bilateral skull bases (parasellar area and orbital apex) from 22 elderly cadavers were made.

RESULTS

A bony septum was less than 300 µm between the SS and ICA and 200 µm between the SS and optic nerve. Parts of the septa were sometimes absent due to fragmentation and holes of the bony lamella (2/22 facing the ICA; 4 facing the ICA in combination with an absent bony septum facing the nerve). In these dehiscence sites, the SS submucosal tissue attached to a thick sheath (50-100 µm in thickness) enclosing the optic nerve and ophthalmic artery and/or the ICA adventitia (50-200 µm in thickness). The ICA sometimes contained a sclerotic plaque that attached to or even protruded into the SS. With or without dehiscence, the SS mucosa was always thin (50-100 µm in thickness) and accompanied no mononuclear cellular infiltration or tumor.

CONCLUSIONS

A thin bony septum of the optic nerve or ICA had been notable as a danger point during surgery, but even a 0.05-mm-thick bone lamella might be an effective barrier against cellular infiltration or bacterial invasion from the SS. Fragmentation and holes of the bony lamella in 4 cadavers might allow cellular invasion to the optic nerve. Accordingly, unknown immunological cross talks might occur to cause demyelination.

Pneumatization Patterns of the Sphenoid Sinus in Adult Nigerians and Their Clinical Implications

BACKGROUND

The variant pneumatization patterns of the sphenoid sinus have significant surgical implications due to their associated inconsistent neurovascular relations. This study aimed at evaluating the pneumatization patterns of the sphenoid sinus in adult Nigerians.

METHODS

This was a retrospective study conducted at the Radiology Department of a Tertiary Hospital in Nigeria after obtaining institutional ethical approval. Brain Computed Tomography images of 336 patients (137 females, 199 males) aged ≥20 years were studied for the variant pneumatization patterns of the sphenoid sinus. Statistical Package for Social Sciences version 23 was used for data analysis. Chi-square test was used to assess for the association of the variants with gender and side. Pvalue was considered significant at <0.05.

RESULTS

The predominant pneumatization pattern in relation to the seller turcica was the sellar type (181;53.9%) followed by the presellar type (65;19.3%), post-sellar (62;18.5%), and lastly the conchal type (28;8.3%). The most prevalent clival recess was the subdorsal type (25;7.4%) followed by the dorsal (18;5.4%), combined (7;2.1%), and lastly occipital (3;0.9%). The frequency of pneumatized anterior clinoid process, greater wing of sphenoid and pterygoid process was 76;22.6%, 60;17.9% and 141;42% respectively and these showed significant side difference (P=0.001 each). None of the pneumatization patterns showed a significant gender difference. Sphenoid sinus agenesis was not observed.

CONCLUSION

The pneumatization patterns in our study varied from the findings in previous Nigerian studies and other populations. There is therefore the need for preoperative evaluation before endoscopic transsphenoidal surgical procedures.