Sphenoid Sinus in Relation to Age, Gender, and Cephalometric Indices

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.

Application of expanding bilateral sphenoid sinus plasty in the treatment of sphenoid sinus diseases

Expanding bilateral sphenoid sinus plasty is an essential technique for the treatment of sphenoid sinus diseases, such as refractory sphenoid sinusitis, sphenoid sinus cyst, fungal sphenoid sinusitis, sphenoid sinus carcinoma and sphenoid sinus chordoma. The present study evaluated the potential application of expanding bilateral sphenoid sinus plasty in the treatment of sphenoid sinus diseases. A retrospective medical record review of 42 patients treated with the expanding bilateral sphenoid sinus plasty from December 2012 to December 2018 was performed in a tertiary-care university hospital. A follow-up of the surgical effects and complications was performed. Of the 42 patients, the symptoms were relieved after operation in all except preoperative hyposmia in 2 and impaired vision in one with no obvious improvement. No complications such as nasal bleeding, olfactory hypofunction and perforation of nasal septum occurred. Follow-up data revealed good mucosal epithelization in all patients within a mean time of 8.6 weeks. Endoscopic sinus reexamination demonstrated that the sphenoid sinus orifice was well opened, and no cases of sphenoid sinus orifice closure were observed. Expanding bilateral sphenoid sinus plasty, with advantages of clearly exposed surgical field, full opening of the sinus cavity, high surgical safety, short epithelialization time and intuitionistic postoperative follow-up, demonstrated great promise for greater use in the treatment of sphenoid sinus diseases in the future.

Volumetric Changes of the Paranasal Sinuses with Age: A Systematic Review

BACKGROUND

There are four pairs of paranasal sinuses: maxillary, ethmoidal, frontal, and sphenoidal. It is common to see changes in size and shape throughout life, so understanding the effect of age on sinus volume can help in radiographic studies and in planning dental and surgical procedures in the sinus-nasal region. The aim of the present systematic review was to perform a qualitative synthesis of available studies which assess the volumetric characteristics of the sinuses and their changes according to age.

MATERIALS AND METHODS

The present review followed PRISMA 2020 guidelines. A systematic advanced electronic search was performed in five databases (Medline (via PubMed), Scopus, Embase, Cochrane, and Lilacs) in June-July 2022. Studies that assessed the volumetric changes of paranasal sinuses with age were eligible for inclusion. A qualitative synthesis of the methodology and results of the included studies was performed. Quality assessment was performed using the NIH quality assessment tool.

RESULTS

A total of 38 studies were included in the qualitative synthesis. Most authors who studied the maxillary and ethmoidal sinuses concluded that it begins its development from birth until the maximum peak of growth, from which it begins to decrease in volume with age. Results regarding the volumetric changes of the frontal and sphenoidal sinuses are mixed.

CONCLUSIONS

Based on the results of the studies included in the present review, it can be concluded that the volume of the maxillary and ethmoidal sinus appears to decrease with age. Conclusions on the volumetric changes of the sphenoidal and frontal sinuses require further evidence.

The Party Wall: Redefining the Indications of Transcranial Approaches for Giant Pituitary Adenomas in Endoscopic Era

The evolution of endoscopic trans-sphenoidal surgery raises the question of the role of transcranial surgery for pituitary tumors, particularly with the effectiveness of adjunct irradiation. This narrative review aims to redefine the current indications for the transcranial approaches for giant pituitary adenomas in the endoscopic era. A critical appraisal of the personal series of the senior author (O.A.-M.) was performed to characterize the patient factors and the tumor's pathological anatomy features that endorse a cranial approach. Traditional indications for transcranial approaches include the absent pneumatization of the sphenoid sinus; kissing/ectatic internal carotid arteries; reduced dimensions of the sella; lateral invasion of the cavernous sinus lateral to the carotid artery; dumbbell-shaped tumors caused by severe diaphragm constriction; fibrous/calcified tumor consistency; wide supra-, para-, and retrosellar extension; arterial encasement; brain invasion; coexisting cerebral aneurysms; and separate coexisting pathologies of the sphenoid sinus, especially infections. Residual/recurrent tumors and postoperative pituitary apoplexy after trans-sphenoidal surgery require individualized considerations. Transcranial approaches still have a critical role in giant and complex pituitary adenomas with wide intracranial extension, brain parenchymal involvement, and the encasement of neurovascular structures.

Development of the sphenoid sinus from newborn to age 18: A computed tomography imaging analysis

OBJECTIVES

The sphenoid sinus (SS) is an important anatomical formation in terms of its location and relationship with important neurovascular structures. It is essential to evaluate the pneumatization and dimensions of the SS with Computed Tomography (CT) in the preoperative period of transsphenoidal interventions to be performed on tumors located in this region. The aim of this study was to evaluate the correlation of the volume and dimensions of the SS measured with CT with age in the period from birth to 18 years of age.

METHODS

In this retrospective study, a total of 360 brain, paranasal sinus, temporal bone and maxillofacial CT scans of individuals from birth to 18 years of age were evaluated. The cohort was divided into 18 groups with 20 (10 female, 10 male) patients in each age group. The height, width, length and volume values of the SS were measured on CT and their correlations with age and the differences between genders were evaluated statistically.

RESULTS

It has been determined that the increases in the size and volume of the SS accelerate especially between 1 and 2 years of age and begins to reach adult dimensions after 12 years of age. Height and length of the sphenoid sinus showed a high correlation coefficient (r = 0.717 and r = 0.731 respectively) with age, while its width and volume showed a moderate correlation coefficient (r = 0.662 and 0.543 respectively). There was no statistically significant difference between the genders in terms of SS height, width, length and volume.

CONCLUSIONS

SS dimensions and volume showed a logaritmic growth pattern from birth to 18 years. The results of this study may help to better understand the normal development of SS in children and may serve as a reference for more comprehensive CT studies. In addition, it can help surgeons to evaluate the developmental characteristics of SS in surgical interventions for SS in children.

Development of the Sphenoid Sinus in Japanese Children: A Retrospective Longitudinal Study Using Three-Dimensional Computed Tomography

Background: The sphenoid sinus (SS) is located close to vital structures, such as the pituitary gland, and it has significant clinical relevance. This study aimed to clarify the growth pattern of the SS in Japanese children using three-dimensional computed tomography (CT). Methods: Seventy-eight participants with congenital, acquired, or external auditory canal cholesteatoma were recruited and underwent CT more than twice during their treatment. Using the volume-rendered images, the size and volume of the SS were measured. Furthermore, on the scout image, the morphological measurements of the cranial base were determined. Results: The size and volume of the SS increased with age, and peaked at the mean age of 15 years. For males, the volume of the SS was smaller than that of females aged <5 years. The growth rate of the SS was significantly higher in males than in females. The maximum growth rate was detected at the age of 12 years for males and 10 years for females. For females, the increase in the length of the anterior cranial base ceased at approximately 10 years of age and remained constant thereafter. In contrast, for males, the length of the anterior cranial base increased gradually until 15 years of age. Conclusions: Considering the similarity of the periods between the adolescent growth spurt and the maximum growth rate of the SS, changes in the size of the SS may be used as an indicator of the physical growth spurt.

Sphenoid sinus pneumatization: the good, the bad, and the beautiful

PURPOSE

To study different types of extension of sphenoid sinus pneumatization detected by CT and examine their correlation with other anatomical variants.

METHODS

Sphenoid sinus pneumatization was characterized (780 hemi-sinuses) on CT scans. Its incidence and correlations with related anatomical variants were evaluated. Dimensions of surgical window were measured in the lateral type, where pneumatization extends beyond a line connecting Vidian (pteregoid) canal (VC) and foramen rotundum (FR).

RESULTS

The lateral recess of the sphenoid sinus was pneumatized in 27.3% of patients with a mean width of 7.59 mm. The distance separating the FR and the VC correlated strongly with the depth of the lateral recess. There was significant positive correlation between pneumatization of lateral recess and Vidian nerve prominence to other pneumatization patterns (lesser sphenoid, frontal, and Maxillary sinuses) (p < 0.0001). Lateral recess pneumatization in coronal cuts was also significantly correlated with anterior-posterior sphenoid pneumatization in sagittal cuts (p < 0.0001).

CONCLUSION

Pre-operative assessment of sphenoid sinus pneumatization is essential in the endoscopic approach to skull base structures to facilitate surgical access and avoid injury of the nearby structures. Our study showed significant correlation among anatomical variants and different measurements which allows the surgeon to predict abnormal anatomy with high accuracy.

[Endoscopic endonasal reconstruction of skull base defects in the lateral recess of the sphenoid sinus: evaluation of computed tomograms for planning operations]

OBJECTIVE

Determine the influence of the anatomical features and sizes of the lateral pocket with a defect on the choice of surgical access and the quality of the performed plastics.

MATERIAL AND METHODS

A retrospective analysis of computed tomograms of 38 patients who underwent surgical treatment at the Burdenko National Medical Research Center for Neurosurgery of the Ministry of Health of Russia about defects of the skull base in the area of the lateral pocket of the sphenoid sinus. The patients were divided into three groups depending on the approach used (the 1st group), the recurrence rate (the 2nd group), and the characteristics of intraoperative visualization of the defect (the 3rd group).

RESULTS

There were no statistically significant differences in anatomical features in patients who underwent trans-pterygoid and transsphenoidal approaches, as well as in patients of the 2nd group. Patients of the 3rd group (with visualization features) showed statistically significant differences between the distance from the defect to the VR line (p=0.007). In patients with good visualization of the defect using direct optics, this distance was shorter than in patients in whom the defect was visualized with an angled endoscope. No other anatomical differences were noted.

CONCLUSIONS

The anatomical features of the lateral pocket structure (type of pneumatization, size and volume) did not affect the choice of access to the defect and the frequency of recurrence. When comparing the approaches, it was noted that the trans-pterygoid access, providing direct visualization of defects, minimizes the risk of recurrence in the postoperative period. An objective anatomical indicator for choosing an access to the defects of the lateral pocket can be the distance from the defect to the VR line: at a distance of more than 0.7 cm, it is advisable to perform a trans-pterygoid approach; at a distance of less than 0.7 cm, it is possible to achieve direct visualization of the defect and perform high-quality plastic surgery with a transsphenoidal access.

Sagittal Cephalometric Evaluation Without Point Nasion: Sagittal G-Triangle Analysis

This study aims to introduce a new sagittal cephalometric measurement, the sagittal G-triangle analysis, to accurately and reproducibly assess the sagittal jaw relationship. Sagittal G-triangle analysis, which consists of angles AXK and BXK, is based on an equilateral triangle (Bo–X–K) constructed using 5 cephalometric landmarks (Ba, Bo, Po, Or, and G). To test the diagnostic efficiency of this analysis, pretreatment cephalometric radiographs of 120 female and 120 male Chinese patients were randomly selected. For each enlisted subject, angles SNA and SNB as well as angles AXK and BXK were measured and recorded. On the basis of the SNA and SNB results, subjects were categorized into 6 groups: maxillary retrognathism, normal maxilla, maxillary prognathism, mandibular retrognathism, normal mandible, and mandibular prognathism. The diagnostic efficiency of angles AXK and BXK were evaluated using various statistical tests. A high correlation was detected between angles SNA and AXK as well as between angles SNB and BXK. Female patients with angle AXK between −2.255° and 2.860° and male patients with angle AXK between −2.615° and 2.120° were considered to have a normal maxilla position. Female patients with angle BXK between −2.61° and 2.93° and male patients with angle BXK between −2.275° and 0.610° were considered to have a normal mandible position. In conclusion, sagittal G-triangle analysis could be used as an alternative method for the evaluation of the sagittal position of the maxilla and mandible in cephalometric analysis.

Correlation Between Anatomic Variations of Sphenoid Sinuses and Pituitary Adenoma

BACKGROUND

Many persons have studied relationship between anatomic variations (AVs) of sphenoid sinuses (SS) and paranasal disease, but no research has been done to reveal the correlation between AVs of SS and sellar region lesions.

OBJECTIVE

To compare AVs of SS between sellar region lesions and healthy persons and analyze factors affecting the volume of SS and explore the correlation between AVs of SS and pituitary adenomas (PAs).

METHODS

Clinical data of 53 PAs as experiment group and 30 healthy persons as control team was reviewed. Computed tomography images of SS performed at Tianjin Huanhu Hospital were studied. The AVs of SS including degree of pneumatization, type of intersinus septum (IS), and volume of SS were evaluated by ITK-SNAP software.

RESULTS

Age, gender, degree of pneumatization, and type of IS had no significant difference between groups, while the volume of SS in experiment group was smaller than that in control group (P < 0.05). The volume of SS was associated with age, sex, degree of pneumatization, type of IS in control group, and degree of pneumatization, type of IS in experiment group. In experiment group, patients with postoperative pathological examination ki67 ≥ 3% had bigger volume and higher recurrent rate (P < 0.05).

CONCLUSION

Visualizing different orientations and 3D model of SS is conducive to the success of trans-sphenoid surgery. Pituitary adenomas can deform the SS leading to smaller volume. The volume of SS can be a factor used to predict the outcome of PAs.

Morphometric characteristics of the sphenoid sinus and potential influencing factors: a retrospective assessment using cone beam computed tomography (CBCT)

The present study aimed to evaluate the morphological characteristics of the sphenoid sinus (SS), and the impact of potential influencing factors on the morphometric features using CBCT imaging. CBCT scans of 148 patients, aged between 15 and 85 (32.88 ± 15.33) years were retrospectively evaluated. DICOM files from the CBCT scans were imported into semi-automatic software and the SS of each patient was assessed for the morphological characteristics including configuration, symmetry, extension, shape, septation, volume, and maximum diameter. Furthermore, potential influencing factors such as age, gender, side, and sinus condition were analysed. A significant association was observed between sinus extension and age. Septation was also found to be significantly associated with age, gender and sinus condition. Besides, sinus volume was significantly associated with gender and sinus condition. No significant influence of shape and side on the morphometric features was noticed. The average volume and diameter of the SS were 6576.92 ± 3748.12 mm³ and 30.48 ± 9.28 mm, respectively. In conclusion, the present findings indicate that age, gender and sinus condition have a significant impact on the morphometric characteristics of the SS. Mature sinuses exhibit a post-sellar extension pattern until middle age. In addition, males, and sinuses with healthy sinus condition have larger volumes compared to females and pathological sinuses.

Sex and Age Determination by Measurement of Foramen Magnum Dimensions on Computer Tomography Scanning Study in the Iranian Population

BACKGROUND

Individual distinguishing evidence may be an imperative field of measurable investigation which demonstrates higher correct expectation rates. This process of recognizable Evidence is facilitated by the assurance of sex and age. In circumstances where there are fragmented and mangled skeletal remains, sex assurance is moderately troublesome, and it becomes important to set up the precision of cadaver bones. Therefore, this study aims to evaluate sexual dimorphism and age determination by measuring foramen magnum (FM) dimensions in the Iranian population using digital computed tomography scan.

METHODS

The study sample consisted of a modern adult Iranian population of 120 males and 109 females (age range: 15-50 years). Length, width, and area of FM, also FM index were measured on base skull computed tomography scan.

RESULT

All of the parameters of FM (length, width, area, and FM index), were larger in men than women. The accuracy of sex determination was up to 50.2. The highest accuracy for sex determination was FM width (67.9). This study also helps craniofacial surgeon for exact reference value of FM, which are authorize neurosurgeons' accessibility to the brain stem approach and FM region with minimum retraction.

CONCLUSIONS

It can be concluded from the result, that morphometric analyze of FM is useful for sex determination but cannot be suitable for age determination.

Paranasal sinus development and implications for imaging

Because the paranasal sinuses continue to develop throughout childhood, radiologists encounter significant anatomical variation when confronted with pediatric imaging studies. Knowledge of the stages of sinus growth is vital to differentiate normal development from abnormally large, hypoplastic or malformed sinuses. Understanding how the paranasal sinuses develop and their expected appearance at different patient ages is important for accurate interpretation of diagnostic imaging. To that end, we provide a brief review of paranasal sinus anatomy and discuss the mechanisms by which each paranasal sinus develops, as well as the implications for imaging. We also provide a practical guide for assessing normal paranasal sinuses in children based on the relationship of the sinuses to anatomical landmarks at various stages of development in order to help pediatric radiologists provide accurate interpretation of diagnostic imaging.

Volumetric Investigation of Sphenoid Sinus in an Elderly Population

The aims of this study were to determine the sphenoid sinus volume in an Austrian population, evaluate the relationship between volume and different types of pneumatization and investigate possible age-related sphenoid sinus volume degeneration in the elderly. A total of 50 human cadaver including 25 male and 25 female samples (=100 sphenoid sinuses, age range 65-100, mean age 84.52 ± 9.50) were selected to obtain volume and anatomical variants of pneumatization by using sphenoid sinus casts, made of quadrofunctional hydrophilic addition reaction silicone. The mean sphenoid sinus volume was 4.79 ± 2.39 cm. Males showed statistically significant larger sinus volumes than females (P = 0.048). The volume differed statistically significant for the different types of pneumatization (P < 0.001). The combined type of sphenoid sinus pneumatization presented the largest volume with 7.20 cm, followed by lateral, clival, sphenoid body, presellar, and conchal sinus type with 5.72, 5.63, 4.25, 2.08, and 0.5 cm, respectively. No significant correlation between age and sphenoid sinus volume was found (P = 0.707). This study highlights the close relationship between volume and morphology of sphenoid sinus and confirms ethnic variability. Moreover, our data shows no age-related volume degeneration.

What Are We Missing From Asymmetric Relationship Between the Retinal Nerve Fiber Layer Thickness Profiles and Sphenoid Sinus Volume?

PURPOSE/AIM OF THE STUDY

Detailed analysis of retinal structure such as the retinal nerve fiber layer can be performed by spectral-domain optical coherence tomography (OCT). There are no published studies concerning a relationship between retinal nerve fiber layer and human sphenoid sinus volumes. We investigated this relationship.

MATERIAL AND METHODS

Spectral-domain OCT. The peripapillary retinal nerve fiber layer (RNFL) thickness and sphenoid sinus volume estimation of both sides of sex-matched patients were retrospectively analyzed.

RESULTS

The mean RNFL thicknesses at the left side (91.8 μm) were significantly smaller than the right side (94.5 μm) (P = 0.040). However, the mean left sinus volume (44.5 cm) is larger than the right side, (34.5 mm) (P < 0.005). Left and right differences of both parameters are statistically significant (P < 0.05).

CONCLUSION

There is a negative correlation between mean RNFL thicknesses and mean sinus volumes. To our knowledge, this article is the first report demonstrating the asymmetry relationship between RNFL and sphenoid sinus volumes.

A new classification proposal for sphenoid sinus pneumatization: a retrospective radio-anatomic study

OBJECTIVES

The sphenoid sinus variations are very diverse and the frequency of these sinus variations is high. During operations involving the sphenoid sinus, such as pituitary surgeries, the surgeon should have detailed information about these variations. The aim of this study is to reclassify the sphenoid sinus pneumatizations in detail and to evaluate the incidence of pneumatization types in a Turkish population according to this classification.

METHODS

New classification proposal was made. In accordance with the proposed new classification, sphenoid sinus pneumatizations were evaluated on CBCT images.

RESULTS

When the posteroanterior pneumatization of 128 patients was evaluated; 2.3% conchal, 3.9% presellar, 35.9% sellar, and 57.8% postsellar pneumatization was detected. Of these cases, 28.9% had anterior pneumatization on the right and 23.4% on the left. When lateral direction pneumatizations were evaluated, lateral body type was found to be the most common on both right (44.1%) and left (42.5%) sides.

CONCLUSION

In this study, sphenoid sinus pneumatizations were evaluated three-dimensionally with the help of CBCT, and a new classification suggestion was made to eliminate the classification confusion we encountered in our previous studies. Pneumatizations and variations can affect the field of operation and even change planning. It should be taken into account that the paranasal sinuses may have variations due to their surgical importance and their close association with many vital structures.

Three-Dimensional CT Morphometric Image Analysis of the Clivus and Sphenoid Sinus in Chiari Malformation Type I

This study evaluated three-dimensional (3D) volumetric image reconstructions to identify morphological differences of the clivus and sphenoid sinus on computed tomography (CT) scans of Chiari malformation type I (CMI) and control subjects. Axial CT images of adult females for 30 CMI subjects and 30 age and body mass index (BMI) matched controls were used for this retrospective study. 3D volumetric reconstructions were created from the bone windows of axial data following image registration for position and orientation correction of the head. The volume, surface area, linear dimensions and spatial position in the x, y, and z-axes were computed separately for the clivus and the sphenoid sinus for each subject. Eleven parameters were found to be significantly different between CMI subjects compared to controls. Most notably, clivus volume was reduced by 31% on average in CMI subjects. In contrast, we found that the sphenoid sinus volume was 38% greater on average in CMI subjects. Moreover, clivus length, height, width, and thickness were 3.7, 2.8, 3.0 and 9.4 mm reduced, respectively, in CMI subjects. This is the first study to demonstrate cephalometric differences in the 3D morphology of the clivus and sphenoid sinus between CMI subjects and controls.

Anatomical Variations of the Nose and Paranasal Sinuses: A Computed Tomographic Study

To evaluate the anatomical variations in computed tomographic (CT) images of paranasal sinuses and to investigate association between them.

DESIGN

Retrospective study.

SETTING

Tertiary care center in the southern part of India.

SUBJECTS

Radiological images of paranasal sinuses belonging to chronic rhinosinusitis patients managed between June 2016 and November 2018.

METHODS

The studied characteristics in the CT images included the deviated nasal septum (DNS), concha bullosa (CB), Haller cell (HC), Onodi cell (OC), pneumatization of anterior clinoid process (ACP), pterygoid base (PB), superior turbinate, inferior turbinate, crista galli (CG), and nasal septum. The height of the lateral lamella of the cribriform plate, the sphenoid pneumatization pattern, and the optic nerve relationship with sphenoid sinus were studied separately. The associations between these factors, and with maxillary sinus opacifications were also investigated. A total of 151 adult patients' CT images were analyzed. The most common manifestations noted were DNS, CB and pneumatized PB, seen in 83.4%, 49% and 47% of the patients respectively. The rates of HC, OC, pneumatized septum, pneumatized CG, and pneumatized ACP were 39%, 23%, 27%, 43% and 27% in that order. Rates of most of these variations were within the range reported in the literature. Chi square test revealed that the OC was independently associated with pneumatized CG and pneumatized septum. The maxillary sinus opacification was related to DNS and CB, but not with protrusion of tooth root into the sinus. Most of the anatomical variations were comparable with the reports across the globe, however, the associations between these variations weren't common in our cohort.

Effect of Sphenoid Sinus Pneumatization on the Surgical Windows for Extended Endoscopic Endonasal Transsphenoidal Surgery

BACKGROUND

Little is known on the impact of the pattern and extent of pneumatization of the sphenoid sinus (SS) on the dimensions of the surgical windows used in extended endoscopic endonasal transsphenoidal approaches. We therefore investigated whether the distances between the 2 optic canals and between the paired paraclival carotid arteries are influenced by the pattern and extent of pneumatization of the SS.

METHODS

One hundred high-resolution computed tomography scans from 47 adult female and 53 adult male patients were analyzed. The pattern of SS pneumatization was classified into conchal, presellar, and sellar types. Sellar-type sinuses were then classified according to a newer detailed classification system. Maximal anteroposterior (AP), transverse (TR), and craniocaudal diameters of the SS, interoptic distance at the limbus sphenoidale (IODL) and at the entrance of the optic canal (IODE) and the intercarotid distance between the paraclival carotids (ICD) were measured. A 2-tailed Mann-Whitney U test and Pearson correlation coefficient (R) were used for statistical analysis. A P value <0.05 was considered statistically significant.

RESULTS

Positive correlation was found between IODL and both AP and TR diameters of the SS; between IODE and both AP and TR diameters of the SS; and between ICD and all diameters of the SS. The highest correlation for each of the IODL, IODE, and ICD was noted with the TR diameter of the SS.

CONCLUSIONS

During the development of the SS, pneumatization progress likely exerts quantitative and direction-specific forces, which gradually increase the interoptic and intercarotid distances.