Ethnic Variation of Sinonasal Anatomy on CT Scan and Volumetric Analysis

Automatic semantic segmentation of the osseous structures of the paranasal sinuses

Endoscopic sinus and skull base surgeries require the use of precise neuronavigation techniques, which may take advantage of accurate delimitation of surrounding structures. This delimitation is critical for robotic-assisted surgery procedures to limit volumes of no resection. In this respect, an accurate segmentation of the osseous structures of the paranasal sinuses is a relevant issue to protect critical anatomic structures during these surgeries. Currently, manual segmentation of these structures is a labour-intensive task and requires wide expertise, often leading to inconsistencies. This is due to the lack of publicly available automatic models specifically tailored for the automatic delineation of the complex osseous structures of the paranasal sinuses. To address this gap, we introduce an open source dataset and a UNet SwinTR model for the segmentation of these complex structures. The initial model was trained on nine complete ex vivo CT scans of the paranasal region and then improved with semi-supervised learning techniques. When tested on an external dataset recorded under different conditions, it achieved a DICE score of 98.25 ± 0.9. These results underscore the effectiveness of the model and its potential for broader research applications. By providing both the dataset and the model publicly available, this work aims to catalyse further research that could improve the precision of clinical interventions of endoscopic sinus and skull-based surgeries.

The Ethmomaxillary Sinus-A False Duplicate Maxillary Sinus

Functional endoscopic sinus surgery consistently benefits from good anatomical knowledge and modern imaging techniques. Ethmoid air cells migrate in specific topographical sites near the ethmoid. Posterior ethmoid air cells that descend into the maxillary sinus (MS) are ethmomaxillary sinuses (EMSs) that into the superior nasal meatus. Few previous studies found EMSs in 0.68% to 16.48% of cases. An EMS differs from a Haller's infraorbital cell nearing the ethmoidal infundibulum. A posterior ethmoid air cell intercalated between the ethmoid, MS and sphenoidal sinus is a Sieur's cell, but it could also be regarded as an EMS. An EMS should be discriminated from a maxillary recess of the sphenoidal sinus. An EMS could determine Onodi's maxillary bulla into the MS. The false duplicate MS described by Zuckerkandl consists of a MS draining into the middle nasal meatus adjoined by an EMS draining into the superior nasal meatus. These are separated by the ethmomaxillary septum. The latter may be confused with an intrasinus septum of the MS if the drainage pathways are not adequately documented. Therefore, a case-by-case anatomic identification of the pneumatic spaces nearing the MS should be performed before surgical endoscopic approaches of the nose and sinuses.

Headaches due to Nasal and Paranasal Sinus Disease

Headache and rhinosinusitis are 2 of the most common conditions seen in clinical practice. Consider sinusitis in those with new-onset headache, along with nasal congestion, maxillary tooth discomfort, anosmia, cough, or fever. Most chronic and recurring headaches, especially if migraine features are present, are not due to sinus disease, with the possible exception of rhinogenic headache due to nasal contact points. Nasal endoscopy and neuroimaging with computed tomography or MRI can confirm diagnosis and guide treatment with antibiotics, adjuvant therapies and surgery.

Computed tomography assessment of maxillary sinus hypoplasia and associated anatomical variations: a systematic review and meta-analysis of global evidence

OBJECTIVE

To summarize the scientific evidence on the prevalence of maxillary sinus hypoplasia (MSH) and associated anatomical variations as assessed by computed tomography scans.

STUDY DESIGN

This PROSPERO-registered systematic review followed the recommendations of the PRISMA guidelines. Search algorithms were constructed for each of the six databases and gray literature. After screening the references (Rayyan®), the extracted data were meta-analyzed according to a random-effects model. The joanna briggs critical appraisal tool assessed the methodological quality of the included studies. The GRADE approach was used to estimate the certainty of the evidence.

RESULTS

From a total of 2781 studies screened, 22 were considered for four meta-analysis. The prevalence of MSH in 7358 patients was 5.65% (CI95% = 4.07-7.47%) with significant heterogeneity between studies (p < 0.001, I2 = 89.30%). MSH was identified in 295 patients, of whom 82.38% (CI95% = 75.82-88.09%) had unilateral hypoplasia and 17.62% (CI95% = 11.91-24.18%) bilateral hypoplasia with moderate heterogeneity between studies (p < 0.0503, I2 = 42.87%). The prevalence of MSH in 9998 maxillary sinuses was 3.77% (95% CI = 2.44-5.38%), with significant heterogeneity between studies (p < 0.001, I2 = 92.84%). Hypoplastic/aplastic uncinate process, concha bullosa and paradoxical concha were the most reported anatomical variations. The studies presented a low-moderate methodological quality. The certainty of the evidence was very low to moderate.

CONCLUSION

The prevalence of maxillary sinus hypoplasia observed was 5.65%, with most cases being unilateral.

Anatomical Variations of the Optic Nerve in the Sphenoid Sinus: Do Ethnic Variations Matter?

There are several variations in the anatomical relations of the optic nerve with the sphenoid sinus. Proper understanding of these variations is clinically important to minimize injuries associated with surgical procedures that involve the sphenoid sinus. CT scans of paranasal sinuses obtained prior to any endoscopic surgery in the sphenoid sinus area is useful for designing operative strategies. Ethnic variations in sinonasal anatomy have been documented. The objective was to study the pattern of relationship between optic nerve and the sphenoid sinus using computerized tomographic imaging in a north Indian population, to compare our findings with previous studies in different ethnic groups and find out if ethnic variations in such a relationship matter. A prospective study was conducted on 300 patients who underwent computed tomography of the paranasal sinuses from Sept 2020 to June 2021. Relationship of optic nerves to the sphenoid sinuses was categorized according to DeLano classification. Pneumatization of the anterior clinoid process and bony dehiscence of optic nerve was also observed. Type 1 position of optic nerve was seen in 69.3%, Type 2 in 20.9%, Type 3 in 3% and Type 4 in 6.8% of sinuses. The pneumatization of anterior clinoid process (ACP) was observed in 10.5% and the bony dehiscence of optic nerve was noted in 6.5% sinuses. Bony dehiscence of optic canal had associated ACP pneumatization in 64.1% sinuses.The variability of the relation of optic nerve to the sphenoid sinus even in the persons of same ethnicity precludes a definite role of ethnicity in these variations. Other factors possibly contributing to such a relationship have been discussed.

Anatomical Variants of Internal Carotid Artery-Results from a Retrospective Study

Background and Objectives: The internal carotid artery (ICA) is a vascular structure that can be easily injured during sinus endoscopic procedures, and surgeons should be familiar with its anatomic variants. The aim of this study was to describe the anatomical variations in the internal carotid artery in relationship to sphenoidal sinuses, using computed tomography (CT). Materials and Methods: In this retrospective study, we evaluated the variations of the ICA in relationship to sphenoidal sinuses in a cohort of 600 patients who were assessed between January 2020 and December 2022 in 'Saint Spiridon' Emergency Hospital, Iasi, Romania. Descriptive statistics were used to characterize our data. Results: The most prevalent anatomical variant was represented by intrasinusal septa with posterior insertion on the ICA (58.6%), followed by procident ICA (58%) and dehiscent ICA (52%). We could not find any statistical significance regarding demographic characteristics among groups. Conclusions: A thorough CT examination should be performed before functional endoscopic sinus surgery, with the identification of anatomical variants of the ICA, in order to prevent its injury with potentially fatal consequences.

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.

Multidetector CT of the Nasal Cavity and Paranasal Sinuses Variations in 73 Patients

Detailed knowledge of the anatomy of the nasal cavity and paranasal sinuses is very important in the diagnosis of pathological processes, planning of endoscopic surgery, and radiologic guiding techniques during certain operations. Observational study. Clinic of Neurosurgery, Institute and Department of Anatomy and Pathology, Clinic and Department for Otorhinolaryngology and Maxillofacial Surgery, Faculty of Medicine. Two heads with brains were serially cut in the axial and coronal planes. 73 individuals, who were enrolled among 1848 patients, underwent examination by multidetector computerized tomography. A nasal septal deviation was seen in 65.8%, and septal pneumatization in 11%. Superior concha pneumatization was observed in 1.4% of patients, middle concha bullosa in 30.2%, and its hypoplasia in 1.4%. The lamina papyracea dehiscence was also present in 1.4%. The uncinate process was absent in 1.4%, and it was pneumatized in 4.2%. Agger nasi cells were noticed in 34.3%, and Haller and Onodi cells in 20.7% each. The olfactory fossa was shallow in 9.7%, deep in 31.6%, and very deep in 58.9%. Absence of the frontal sinus was seen in 9.7%. The presellar type of the sphenoidal sinus was present in 11%, the sellar in 35.7%, and the postsellar in 53.5%. Hypoplasia of the maxillary sinus was revealed in 1.4%, and hyperpneumatization in 4.2%. The sinus floor was usually below the level (60.3%), at the same level (20.7%), or above the level of the nasal floor (19.2%). The bony septum within the sinus was seen in 52.1%. The presented data are of a great significance in order to avoid a misdiagnosis of the anatomic variations, to make a proper diagnosis of certain diseases, and for safe endonasal operations.

Racial, Ethnic, and Gender Variations in Sinonasal Anatomy

BACKGROUND

Complications during endoscopic sinus surgery often result from unfavorable anatomy. The prevalence rates of such anatomic findings vary tremendously in the literature, in part due to the small, homogenous populations previously studied.

OBJECTIVE

To characterize the prevalence of sinonasal anatomic variants among ethnic groups and genders seen at an academic medical center.

METHODS

This is a retrospective cross-sectional study of adult subjects who underwent CT imaging of the sinuses from January 2019 to November 2020 at a tertiary academic setting. CT scans were analyzed systematically by 3 trained study personnel for the presence of critical sinus anatomic variants that endoscopic sinus surgeons typically evaluate for preoperatively. Chi-squared tests and analyses of variance were conducted to detect differences in the prevalence of structural findings between genders and races/ethnicities.

RESULTS

A total of 489 subjects (57% female) were included: 44 Asian, 14 Black/African American, 101 Hispanic/Latino, 203 White, 127 Other. The prevalence of the following anatomical variants differed by race/ethnicity: Haller cells, Type 3 optic nerve, Onodi cells, maxillary septations, sphenoid lateral recess, anterior clinoid process pneumatization, and carotid artery dehiscence. Asian subjects had higher rates of Haller cells (48% vs 16%, P < .001) and Type 3 optic nerve (18% vs 4%, P = .022) compared to Hispanic subjects, as well as a higher prevalence of Onodi cells (39% vs 17%, P = .003) compared to White subjects. Males had a higher prevalence of mesenteric anterior ethmoid arteries (62% vs 45%, P < .001) and dehiscent carotid arteries (30% vs 21%, P = .024).

CONCLUSION

Certain sinonasal anatomic variants, which have direct implications for complications during endoscopic sinus surgery, were found to be significantly more prevalent in some demographic groups. Surgeons should be aware of these differences in their review of preoperative imaging for safe surgical planning.

Anatomical Variations of the Sinonasal Area and their Clinical Impact on Sinus Pathology: A Systematic Review

Introduction  Anatomical variations of the nasal cavity and of the paranasal sinuses are frequently encountered and play an important role in dysfunctional drainage of sinuses. However, it is not clear in the literature whether they predispose to sinus pathology.

Objectives  The aim of the present review is to summarize the understanding of the association between anatomical variations of the sinonasal area and sinus pathology.

Data Synthesis  The present review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We performed a thorough research on PubMed from October 2004 until May 2020 by using the search terms paranasal sinus anatomical variations and sinus disease , sinusitis , and mucosal disease .

Thirty studies were eligible and were included in the analysis. Overall, the studies encompassed a total of 6,999 patients included in the present review. In many studies, it has been statistically established that certain anatomical variations increase the risk of sinus disease. On the other hand, the rest of the collected studies failed to show any statistically significant correlation between anatomical variants and sinus pathology.

Conclusion  The present study highlights the possible correlation between some anatomical variations of the sinonasal area and pathologies of the paranasal sinuses. Careful assessment and computed tomography (CT) in patients with chronic rhinosinusitis is needed, especially in those undergoing endoscopic surgery, to identify and treat anatomical variations in the paranasal sinuses that may be correlated with rhinosinusitis. Due to contradictory results in the literature, further research is needed to elucidate the effects of anatomical variants of the sinonasal area.

Prevalence of the anatomical variations of concha bullosa and its relation with sinusitis among Saudi population: a computed tomography scan study

Concha bullosa (CB) is a pneumatic cavitation inside a concha in the nasal cavity. It is one of the most widely recognized nasal variations and is mostly found in the middle concha. CB is divided according to its site into three types; lamellar, bulbous and extensive. The goal of our study was to estimate the prevalence of CB among Saudi adult population and its association with sinusitis by using multidetector computed tomography (MDCT). This was a retrospective study carried out over a three-year period on 879 adult Saudi patients aged 18 years or older, referred for MDCT assessment of paranasal sinuses. Males were 540 and females were 339. Patients with facial congenital anomalies or nasal trauma were excluded from our study. CB was prevalent in both males and females among Saudi population (55.4%, 55.7%) respectively. Bilateral CB (55.5%) was more frequent than unilateral (44.5%). Extensive CB (44.0%) was the most frequent type. Sinusitis was associated more in patients with CB (48.0%) versus those who have no CB (5.9%). In conclusion, CB was prevalent among Saudi population and the most frequently recorded is the extensive type. Furthermore, the most common type associated with sinusitis was extensive CB (49.6%).

Anatomical Variations of the Nasal Cavities and Paranasal Sinuses: A Systematic Review

The anatomy of the nasal cavities and paranasal sinuses is one of the most varied in the human body. The aim of this study is to review the prevalence of anatomical variations in the sinonasal area. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We performed on PubMed a literature search from October 2004 until May 2020. The search strategy included the following keywords: ('paranasal sinus' OR 'frontal sinus' OR 'maxillary sinus' AND ('anatomical variants' OR 'anomalies')). Fifty studies were eligible and included in the analysis. Overall, the studies encompassed a total of 18,118 patients included in this review. Most common anatomical variations include agger nasi cells, nasal septum deviation and concha bullosa. Other variations seen in this region are uncinate process variations, paradoxical middle turbinate, Haller, Onodi and supraorbital ethmoid cells, accessory ostia of maxillary sinus. Less common variations include any sinus aplasia, crista galli pneumatization and dehiscence of the optic or maxillary nerve, internal carotid artery and lamina papyracea. Anatomical variations of this region also differ among ethnic groups. This study highlights the amount, variability and significance of most anatomical variants reported in the literature in the last years. It is essential for the sinus surgeon to have a broad spectrum of knowledge not only of "the typical" anatomy but also all the possible anatomical variations. With modern imaging modalities, anatomical variations can be detected, and uneventful pitfalls might be prevented.

A CT-Scan review of anatomical variants of sinonasal region and its correlation with symptoms of sinusitis (nasal obstruction, facial pain and rhinorrhea)

Objective:

To determine the incidence of anatomical variants of sinonasal region and its correlation with symptoms of sinusitis.

Methods:

The study was conducted from January-June 2020 at Radiology Department of PNS Shifa Hospital, Karachi. The study involved 50 symptomatic subjects of sinusitis with age ranges from 18-60 years which were prepared for computed tomography of paranasal sinuses. The scans were reviewed for nasal-septum, turbinates, uncinate process, ethmoid air-cells along with other anatomical variants and were correlated with symptoms of sinusitis.

Results:

Out of 50 subjects, 34 were males and 16 were females with mean age of 42.68±18.22 years. Most common anatomical variants observed were agger nasi cells (64%), deviated nasal septum (56%), and concha-bullosa (46%). Statistically significant correlation existed between bilateral agger nasi cells and nasal obstruction (p=0.017, ρ= -0.336).

Conclusion:

The anatomy of sinonasal region is highly complex. However, anatomical variants can disturb the sinus mucociliary drainage pathway resulting in patient suffering. Therefore, considering the variable anatomy of sinonasal region, CT-PNS is recommended for every subject in order to avoid surgical hazards.

Anatomical and Volumetric Analysis of the Sphenoid Sinus by Semiautomatic Segmentation of Cone Beam Computed Tomography

This investigation was performed to analyze and evaluate anatomical and volumetric data of the sphenoid sinus by semiautomatic segmentation of cone beam computed tomography (CBCT) datasets.This analysis was carried out on cone beam computed tomography images of 100 patients. By using the discretionary software "ITK-Snap", the volumetric investigation of 197 sphenoid sinuses was conducted. The statistical analyses were carried out by using the paired and independent Student t-test. In addition, the Pearsons chi-square test was performed. P values P < 0.05 were considered significant.The volumetric mean was 4.438 ± 2.434 cm for the right and 4.809 ± 3.000 for the left side. Results did not indicate statistically significant differences according to the side, irrespective of gender (P > 0.05). The further investigation of differences between male and female patients did assess significant results (P < 0.05), males (10.477 ± 3.851 cm) present a larger total sinus volume than females (8.219 ± 3.574 cm). In accordance to patients' age (median 54 years), smaller volumes were related to younger patients and larger volumes to older ones. But, no statistically significant results in accordance to age could be detected (χ = 1.258; P > 0.05).Endoscopic sinus surgery of the vulnerable and intricate anatomy of the sphenoid sinus requires an explicit knowledge and orientation about the anatomical variations such as septums and volumetric capacity. Concerning this matter, semiautomatic segmentation of CBCT images can aid the surgeon in preoperative planning. Our investigation shows that a small sinus volume, that is, affecting female patients and a complex sinus anatomy by the occurrence of a septum, especially located close to neurovascular structures could essentially aggravate endoscopic sphenoid sinus surgery. In this regard, volumetric analysis of the sphenoid sinus by CBCT images can provide presurgical information and facilitates an individualized treatment.

Relationship between Sinonasal Anatomical Variations and Symptom Severity in Patients with Chronic Rhinosinusitis

Background

Anatomical variations are subtle structural abnormalities around the osteomeatal complex that might obstruct paranasal sinus drainage and ventilation. The role of these anatomical variants in chronic rhinosinusitis is still controversial and unclear. The aim of this study was to determine the prevalence of anatomical variations and their relationship with the severity of symptoms in patients with chronic rhinosinusitis.

Materials and Methods

This was a cross-sectional study conducted among randomly selected patients with chronic rhinosinusitis. Sinonasal Outcome Test-20 (SNOT-20) was used to assess the patient's severity of symptoms. Computed tomographic scan was used to determine the presence of anatomical variations. The relationship between anatomical variations and symptom severity was determined using the Statistical Products and Service Solution (SPSS) version 20.0.

Results

There were 70(58.3%) males and 50(41.7%) females within the age range of 17-60 years. SNOT-20 scoring showed 6(5.0%) of the patients with mild symptoms, 69(57.5%) with moderate, 37(30.8%) with severe, and 8(6.7%) with profound symptoms. The prevalence of sinonasal anatomical variants was 26.7%, which comprised of septal deviation (10.8%), agger nasi (6.7%), concha bullosa (4.2%), Haller cells (3.3%), and Onodi cells (1.7%). There was a statistically significant relationship between the anatomical variations and symptom severity (P = 0.000).

Conclusion

This study found a significant relationship between anatomical variations and severity of chronic rhinosinusitis. The prevalence of anatomical variants was found to be 26.7%.