Do altitude and climate affect paranasal sinus volume?

Variation, sexual dimorphism, and enlargement of the frontal sinus with age in adult South Africans

OBJECTIVES

To document frontal sinus volume (FSV) in a sample of sub-Saharan Africans with a view to evaluating claims that such populations exhibit comparatively small sinuses. This study also addresses questions related to sexual dimorphism, incidence of sinus aplasia, and the possibility that FSV continues to increase through adulthood.

MATERIALS AND METHODS

FSV was measured from CT scans of adult crania from the Dart Collection. Sex and age were known for each individual. Linear cranial dimensions were used to compute a geometric mean from which a scaled FSV was computed for each cranium.

RESULTS

FSV does not differ significantly between sexes, but females exhibit a higher incidence of aplasia. There is considerable variation in FSV in this sample, with the average ranking among the higher means reported for other population samples. The incidence of FS aplasia falls within the range of values recorded for other population samples. Although our study is cross-sectional rather than longitudinal, there is strong evidence that FSV continues to increase with age throughout adulthood.

DISCUSSION

The FSV mean of our sample contradicts the notion that sub-Saharan Africans possess small sinuses. In a global context, geography (climate and altitude) does not appear to be related to FSV. The absence of sexual dimorphism in our sample is unexpected, as significant dimorphism has been reported for most other population samples. Our results support other indications that the frontal sinus continues to expand throughout adulthood, especially in females, and that it is likely due to bone resorption.

Sex Estimation From the Paranasal Sinus Volumes Using Semiautomatic Segmentation, Discriminant Analyses, and Machine Learning Algorithms

ABSTRACT

The aims of this study were to determine whether paranasal sinus volumetric measurements differ according to sex, age group, and right-left side and to determine the rate of sexual dimorphism using discriminant function analysis and machine learning algorithms. The study included paranasal computed tomography images of 100 live individuals of known sex and age. The paranasal sinuses were marked using semiautomatic segmentation and their volumes and densities were measured. Sex determination using discriminant analyses and machine learning algorithms was performed. Males had higher mean volumes of all paranasal sinuses than females ( P < 0.05); however, there were no statistically significant differences between age groups or sides ( P > 0.05). The paranasal sinus volumes of females were more dysmorphic during sex determination. The frontal sinus volume had the highest accuracy, whereas the sphenoid sinus volume was the least dysmorphic. In this study, although there was moderate sexual dimorphism in paranasal sinus volumes, the use of machine learning methods increased the accuracy of sex estimation. We believe that sex estimation rates will be significantly higher in future studies that combine linear measurements, volumetric measurements, and machine-learning algorithms.

A comparative study of paranasal sinus and nasal cavity anatomic variations between the Polish and Turkish Cypriot Population with CBCT

Background

Genetic and environmental factors especially climatic conditions are thought to influence the shape and size of the paranasal sinuses and anatomic variations may create both a diagnostic and therapeutic challenge. However, no study has been published about the climatic adaptation of the paranasal sinus region in different populations. This study aimed to compare the prevalence of anatomical variants in the paranasal sinus and nasal cavity using Cone-Beam Computed Tomography (CBCT) between Polish and Turkish Cypriot populations.

Methods

The material consisted of volumes acquired utilizing Galileos (Sirona, Germany) as well as Newtom 3G (QR Verona, Newtom, Italy) CBCT units. There were examined 356 Polish and 359 Turkish Cypriot patients in whom paranasal sinuses were included in the field of view. Paranasal sinus anatomic variations were assessed in both populations.

Results

In the Polish population, the most common anatomic variation was septum deviation followed by the Agger nasi cell and concha bullosa with a prevalence of 87.7%, 83.2%, and 54.8% respectively. For the Turkish Cypriot population, the most common anatomic variation was Agger nasi cell followed by concha bullosa and supraorbital ethmoid cells with a prevalence of 81.6%, 68%, and 57.8% respectively. Many anatomic variations were found to show substantial differences among both populations. Incidence rates of hyperpneumatization of the frontal sinus, septum pneumatization, supraorbital ethmoid cells, concha bullosa, uncinate bulla, and internal carotid artery protrusion into the sphenoid sinus were significantly higher in the Turkish Cypriot group, while the incidence of Haller cell, frontal sinus hypoplasia, maxillary sinus hypoplasia, ethmomaxillary sinus, sphenomaxillary plate, and septum deviation were significantly higher in Polish population.

Conclusion

According to the Köppen-Geiger world climatic map, the climate is warmer and drier in Turkish Cypriote populations than in the Polish population. These climatic differences influence the paranasal sinus variations between the Turkish Cypriot and Polish populations that must be taken into account by rhinologic surgeons especially when performing frontal and sphenoid sinus surgery.

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.

Intraoperative Head Slippage with the Head Clamp System Can Occur During Epileptic Surgery

BACKGROUND

During neurosurgery, we use a head clamp system for firm head fixation. However, we have encountered slippage using the head clamp system, although this has not been adequately studied. In the present study, to increase the reliability of the analysis using a more homogeneous type of patient data, we conducted a prospective study of patients who had undergone epileptic surgery. We examined the potential risk factors for head slippage and postulated that the location of the pins might be important.

METHODS

We reviewed and compared the positions of the fixed head of the patients on fused preoperative and postoperative computed tomography images. We measured the distance between the corresponding head pins to determine the association with head slippage. We statistically compared the relationship between each head pin and the nasion-inion line. We also assessed age, sex, body weight, body mass index, surgical position, surgical duration, and craniotomy volume as potential risk factors for slippage.

RESULTS

Head slippage was observed in 3 of 21 patients (14%) in the present prospective study. The most caudal head pin position was not associated with head slippage in the present study. However, the center point between the most caudal point and the most cranial point was significant (P = 0.014). A center point between the most caudal and most cranial pins from the nasion-inion line that was >6.5 cm was more likely to result in slippage.

CONCLUSIONS

We should consider that head clamp slippage could occur intraoperatively.

The Unified Airway: Does Asthma Influence Paranasal Sinus Pneumatization?

Asthma has been implicated as a driving force in lower airway remodeling; however, its effect on upper airway development has not been studied. Clinical disease, particularly cystic fibrosis (CF), has been associated with anatomical paranasal sinus variation, although the mechanism for these variations remains unclear. The purpose of this study was to determine whether asthma is associated with altered sinus pneumatization. Five hundred ninety-one computed tomography scans, including 303 adolescents (age 13-18) and 288 adults (age > 18), were evaluated using the Assessment of Pneumatization of the Paranasal Sinuses (APPS) instrument. The APPS score is validated for assessing anatomical variation and total sinus volume. A diagnosis of asthma was ascertained from the medical record, and patients with CF were included as a positive control group. Patients with asthma had mean APPS score of 9.66, compared to 9.85 for participants without asthma (P = .585). Subgroup analysis demonstrated similar findings among adults (P = .817) and adolescents (P = .585). Patients with a diagnosis of CF had significant sinus hypoplasia according to a mean APPS scores of 3.50 (P < .001). Sinus hypoplasia persisted in both adults (P < .001) and adolescents (P < .001) with CF. The presence of asthma is not associated with altered paranasal sinus pneumatization. In contrast, CF is associated with significantly reduced sinus pneumatization. These findings suggest that aberrant sinus pneumatization may not be a feature of asthma and that chronic mucosal respiratory disease is not a generalizable cause for altered paranasal sinus pneumatization.

Evaluation of volume of the sphenoid sinus according to sex, facial type, skeletal class, and presence of a septum: a cone-beam computed tomographic study

We have used cone-beam computed tomographic (CT) images to retrospectivelyevaluate the influence of sex, skeletal class, facial type, and the presence of septa on the volume of the sphenoid sinus in 172 images from 85 men (mean (SD) age 28 (2) years) and 87 women (mean (SD) age 30 (1) years). Skeletal class and facial type were calculated for each patient from multiplanar reconstructions using NemoCeph® software. Volumetric analysis of the sphenoid sinus was made with the help of the ITK-SNAP® 3.4.0 segmentation software, while the presence or absence of septa in the sphenoid sinus was evaluated with the Carestream 3D Imaging® software 3.4.3. We analysed the results using two-way ANOVA, Student's independent sample t test, and Fisher's exact test, as appropriate, and probabilities of <0.05 were accepted as significant. Sex (p=0.0946), facial type (p=0.790), and skeletal class (p=0.120) had no significant influence on the volume of the sphenoid sinus, and nor did the volumes of the right and left sphenoid sinuses (p=0.0923), or the presence of a septum within the sinus (p=0.330) in its volume.

Relationship between sphenoid sinus volume and protrusion of internal carotid artery and optic nerve: a 3D segmentation study on maxillofacial CT-scans

PURPOSE

Anatomy of sphenoid sinuses has acquired a growing importance with the diffusion of transsphenoidal surgical procedures. A common risk in these practices is the damage of internal carotid artery (ICA) and optic nerve (ON), which may protrude into the sphenoid air cavities. This study aims at analysing the relationships between sphenoid sinuses volume and protrusion of ICA and ON.

METHODS

260 head CT-scans were retrospectively analysed (equally divided among males and females, age range 20-92 years). Volume was segmented through ITK-SNAP software. In addition, the subjects were classified into four groups: no protrusion of any structure (group 1), protrusion of ICA (group 2), protrusion of ON (group 3), protrusion of both ICA and ON (group 4). Possible statistically significant differences in prevalence of the four groups according to gender were assessed through Chi-squared test (p < 0.05). Differences in volume between the four groups were assessed through one-way ANOVA test (p < 0.05), separately for males and females.

RESULTS

Group 1 was the most frequent (40.0%), followed by group 4 (27.7%) and group 2 (18.5%), without any difference according to gender. For what concerns volume, cases of ICA and concomitant ICA + ON protrusion had significantly larger sinuses, whereas isolated ON protrusion did not modify sinus volume.

CONCLUSIONS

Results show that protrusion of ICA is positively related with the volume of sphenoid sinuses, whereas the same relation was not verified for ON: surgeons should accurately consider possible ON protrusion in each case, as it may occur independently from sphenoid sinuses volume.

Frontal sinus ontogeny and covariation with bone structures in a modern human population

In humans, the frontal sinus (FS) is located in the medial part of the supraorbital region, sometimes expanded throughout the frontal squama. It exhibits high morphological variability, but its general form appears to be constrained by surrounding structures. The goal of this study is to analyze FS growth and test for covariation between FS volume and the glabellar region, upper nasal region, bone thickness and endocranial size in a human sample from Argentina. The sample comprises 149 reconstructions derived from computed tomography images of individuals aged 0-31 years. Volume of the FS and measurements of the surrounding structures were recorded. The FS growth trajectory was assessed by parametric and nonparametric methods, and covariation was determined using correlations and partial correlations. The FS volume could be measured at an age of about 6 years and older; adults had no aplasia but hyperplasia was found in some cases. Since the most conspicuous characteristic found was variation among individuals, the nonparametric smoothing spline produced very poor fitting. The modified logistic function was the only parametric method providing significant parameters. Sexes differed in the age at which FS growth began and ended, with FS developing earlier but at a slower rate in females than in males. The FS volume did not correlate with either upper nasal width or endocranial volume, but it correlated with bone thickness measurements (mainly from the glabellar region), even when age was held constant. Expansion of the FS at the frontal poles also correlated with frontal bone thickness. Despite the difficulty in modeling and predicting the trajectory and morphology of FS, our results suggest that it is affected by its surrounding bony environment.

Computed tomography-based volumetric tool for standardized measurement of the maxillary sinus

Volume measurements of maxillary sinus may be useful to identify diseases affecting paranasal sinuses. However, literature shows a lack of consensus in studies measuring the volume. This may be attributable to different computed tomography data acquisition techniques, segmentation methods, focuses of investigation, among other reasons. Furthermore, methods for volumetrically quantifying the maxillary sinus are commonly manual or semiautomated, which require substantial user expertise and are time-consuming. The purpose of the present study was to develop an automated tool for quantifying the total and air-free volume of the maxillary sinus based on computed tomography images. The quantification tool seeks to standardize maxillary sinus volume measurements, thus allowing better comparisons and determinations of factors that influence maxillary sinus size. The automated tool utilized image processing techniques (watershed, threshold, and morphological operators). The maxillary sinus volume was quantified in 30 patients. To evaluate the accuracy of the automated tool, the results were compared with manual segmentation that was performed by an experienced radiologist using a standard procedure. The mean percent differences between the automated and manual methods were 7.19% ± 5.83% and 6.93% ± 4.29% for total and air-free maxillary sinus volume, respectively. Linear regression and Bland-Altman statistics showed good agreement and low dispersion between both methods. The present automated tool for maxillary sinus volume assessment was rapid, reliable, robust, accurate, and reproducible and may be applied in clinical practice. The tool may be used to standardize measurements of maxillary volume. Such standardization is extremely important for allowing comparisons between studies, providing a better understanding of the role of the maxillary sinus, and determining the factors that influence maxillary sinus size under normal and pathological conditions.

Volumetric assessment of sphenoid sinuses through segmentation on CT scan

PURPOSE

Computed tomography represents the gold standard for the assessment of morphological characteristics of sphenoid sinuses, whose anatomy has acquired a novel interest because of the recent introduction of transsphenoidal surgery and robot-assisted procedures. One of the most relevant parameters for planning surgical intervention is the volume of sphenoid sinuses, and with time few population studies have been published. However, at present, no data are available concerning the relation between volume and anatomical variants of sphenoid sinuses.

METHODS

We retrospectively evaluated head CT-scans of 100 patients (age range 25-99 years; mean age males 45.0; mean age females 50.5 years) to calculate the volume of sphenoid sinuses through automatic segmentation. Possible statistically significant differences according to sex and variants of pneumatization, and type of sinus were assessed, respectively, through Student's t test and one-way ANOVA test (p < 0.05).

RESULTS

Average volume of sphenoid sinuses in males was 10.005 ± 5.101 cm³, in females 7.920 ± 3.176 cm³. Differences according to sex were statistically significant (p < 0.05). Patients with pneumatization of pterygoid processes, dorsum sellae and anterior clinoid processes had a significantly higher volume than unaffected subjects. Moreover, differences of volume according to the type of sphenoid sinus were statistically significant (p < 0.05).

CONCLUSIONS

Results show that volume of sphenoid sinuses strongly depend upon the type of sinus and possible pneumatization variants. Moreover, the important of ethnic variability is confirmed.

Sphenoethmoid Cell: The Battle for Places Inside of the Nose Between a Posterior Ethmoid Cell and Sphenoid Sinus: 3D-Volumetric Quantification

Background

Sphenoethmoid cells may be above the sphenoid sinus with/ or without con-tact to optical nerve. Although sphenoethmoid cells are theoretically considered to possibly influence the sphenoid sinus volume, we could not find any study in the literature on this issue.

Aims

The aim of our study was to detect sphenoethmoid cells and measure the sphenoid sinus vol-ume using multiplanar computerized tomography and also investigate the correlation between the presence of sphenoethmoid cells and the sphenoid sinus volume.

Methods

Retrospectively 141 patients who had available paranasal computerized tomography images were included in this study. The sphenoid sinus volumes of each patient were calculated individually for each side, and the relationship between the presence of sphenoethmoid cell and sphenoid sinus volume was investigated.

Results

Sphenoethmoid cells were detected at 106 (37.5%) of the total 282 sides in 141 patients. No gender difference was observed. The total sphenoid sinus volume was significantly lower in the group of patients who had bilateral sphenoethmoid cells than in the sphenoethmoid cell negative group. In patients with a unilateral sphenoethmoid cell, a significant decrease in the sphenoid sinus volume was observed only for the side where the sphenoethmoid cell was located.

Conclusion

It was observed that the sphenoethmoid cells caused a significant reduction in the sphe-noid sinus volume on the side where they were located. In the case of low sphenoid sinus aeration, the sphenoethmoid cell should be kept in mind. Further studies with an extended patient series are required to explore this issue.