Change of frontal sinus in age of according to the international frontal sinus anatomy classification.

BACKGROUND: The radiological and surgical anatomy of the frontal sinus should be well-known in all age groups to successfully manage frontal sinus diseases and reduce the risk of complications in sinus surgery. PURPOSE: To define frontal sinus and frontal cells according to the International Frontal Sinus Anatomy Classification (IFAC) criteria in pediatrics and adults. MATERIAL AND METHODS: A total of 320 frontal recess regions of 160 individuals (80 pediatric, 80 adults) who underwent a computed tomography (CT) scan of the paranasal sinus (PNS) were included in the study. Agger nasi cells, supra agger cells, supra agger frontal cells, suprabullar cells, suprabullar frontal cells, supraorbital ethmoid cells, and frontal septal cells were evaluated in the CT analysis. RESULTS: The incidence rates of the investigated cells were determined to be 93.1%, 41.9%, 60.0%, 76.3%, 58.5%, 18.8%, and 0% in the pediatric group, respectively, and 86.3%, 35.0%, 44.4%, 54.4%, 46.9%, 19.4%, and 3.4% in the adult group, respectively. Considering the unilateral and bilateral incidence of the cells, agger nasi cells were highly observed bilaterally in both the pediatric group (89.87%) and the adult group (86.48%). CONCLUSION: Our study results show that IFAC can be used as a guide to increase the chance of surgical treatment in the pediatric and adult groups and that the prevalence of frontal cells can be determined radiologically and contributes to the generation of estimations of the prevalence of frontal cells.

The prevalence of frontal cell variants according to the International Frontal Sinus Anatomy Classification and their associations with frontal sinusitis.

BACKGROUND: The International Frontal Sinus Anatomy Classification (IFAC) is introduced to simplify the classification of different frontal cell variants based on their topographical structures. The objectives of our study were to determine the prevalence of the frontal cell variants according to IFAC and their association with the development of frontal sinusitis. METHODOLOGY: A retrospective chart review on computed tomography paranasal sinus (CTPNS) was conducted. A total of 200 patients who had clinical and endoscopic findings of chronic rhinosinusitis (CRS) and undergone CTPNS were reviewed. The CTPNS was evaluated for the presence of frontal cell variants according to IFAC and mucosal changes consistent with frontal sinus involvement. RESULT: A total of 400 sides of the CTPNS were analyzed. The agger nasi cells (ANCs) were the most common (95.5%) followed by supra bulla cells (SBCs) (60.8%), supra bulla frontal cells (SBFCs) (53.0%), supra agger cells (SACs) (50.0%), supra agger frontal cells (SAFCs) (36.0%), frontal septal cells (FSCs) (8.3%), and supraorbital ethmoidal cells SOECs (5.5%). There was significant association between SOEC (p = 0.001) and FSC (p = 0.044) with the development of frontal sinusitis. CONCLUSIONS: Apart from ANCs, the posterior-based cells (SBCs and SBFCs) have higher prevalence than the anterior-based cells (SACs and SAFCs). Despite being the least, both SOECs and FSCs are significantly associated with frontal sinusitis.

The imaging anatomy of ethmomaxillary sinus and its impact on chronic rhinosinusitis.

PURPOSE: The aim of this study was to investigate the pneumatization degree of ethmomaxillary sinus (EMS) and adjacent structures, and its impact on chronic rhinosinusitis (CRS). METHODS: A retrospective analysis of paranasal sinus CT scans of 996 patients was conducted. The maximum vertical diameter of EMS in the coronal plane was measured, allowing EMS to be classified, and its impact on ipsilateral CRS were examined. RESULTS: The prevalence of EMS was 11.9%. The maximum vertical diameter of EMS in the coronal plane ranged from 3.68 to 28.76 mm with a mean (± SD) of 11.32 ± 5.12 mm. The prevalence rates of EMS in CRS sides and non-CRS sides were 12.5% and 9.3%, respectively, which was significantly different (χ2 = 4.495; p < 0.05). The difference in prevalence between the three types of EMS in ipsilateral CRS was statistically significant (χ2 = 6.733; p < 0.05). The difference in Lund-Mackay (LM) score of ipsilateral CRS between the three types showed no statistically significant difference (H = 4.033; p > 0.05). CONCLUSION: EMS is a common anatomical variation with marked individual differences in shape and pneumatization degree. A higher degree of EMS pneumatization may contribute to the occurrence of CRS; this should be investigated before surgery.

Biological relationships and frontal sinus similarity in skeletal remains with known genealogical data.

Frontal sinus analysis has potential utility for detecting biologically related individuals. However, the methodological approach to its evaluation, as well as its informative value, have been questioned. The aim of this work is to introduce a new approach to evaluating the frontal sinus using the 'external supraorbital line' (ESOL) and to determine whether there are sex differences within families in frontal sinus measurements and whether frontal sinus similarity reflects known genetic relationships in both measurements and morphology. We examined the skeletal remains of 41 adult individuals (25 males, 16 females), all members of one family over four generations (19th to 20th centuries), including individuals with very close consanguinity. CT images of skulls were acquired, and both the dimensions and morphology of the frontal sinuses were analyzed using their portions above the ESOL. No significant sex differences were found within families based on frontal sinus dimensions. Significant relationships were found between biological distance and the maximum height and morphology of the frontal sinuses. The greatest degree of similarity was found among closely related individuals. Additionally, in several cases, there was a greater degree of similarity between first cousins or grandparents and their grandchildren than among siblings or parents and their children. Total surface, volume and width are not significant indicators of relatedness. Known genetic relationships are also supported by individual morphological features. Variability within families with very close consanguineous relationships was lower than within families with common degrees of consanguinity, although differences are significant only for some variables.

Risk factors in lateral window sinus elevation surgery.

Maxillary sinus augmentation is the most predictable of the pre-prosthetic surgical procedures. There are, however, known and well-documented complications that can and do occur. The most common are the intraoperative complications of sinus membrane perforation and bleeding, and the postoperative complications of sinus graft infections, sinus infections, and sinusitis. The majority of these complications can be prevented, or their incidence greatly reduced, through a thorough understanding of maxillary sinus anatomy, the multifaceted etiologies of these conditions, and the steps that can be taken to avoid them. This volume of Periodontology 2000 will discuss both the preoperative and intraoperative procedures that will prevent these untoward outcomes and the necessary treatment modalities that will limit their adverse effects.

Incidence of anatomical variations according to the International Frontal Sinus Anatomy Classification (IFAC) and their coincidence with radiological sings of opacification.

BACKGROUND: The endonasal access to the frontal recess and sinus may be complicated by a variety of anatomical variations. Previous classifications of these variants were characterized by proper names or position information without anatomical reference. The IFAC is intended to simplify the classification of anatomical variations of the frontoethmoidal complex. The aim of this study was to analyse a representative number of sinus CT scans to assess the incidence of anatomical variations according to the IFAC and to compare the results with previous classifications. In addition, the coincidence of complex anatomical variations and radiological sings of opacification was investigated. METHODOLOGY/PRINCIPAL: Two hundred and forty-nine sinus CT scans were analysed in multiplanar reconstructions. Exclusion criteria were previous operations on the paranasal sinuses, malignant diseases, and an insufficient image quality. All anatomical variants were analysed according to the IFAC criteria. In addition, the coincidence of radiological sings of opacification and the presence of anatomical variations of the frontal recess and sinus were investigated. RESULTS: The analysis revealed Agger nasi cells in 95% of the CT scans. Supra agger cells (SACs) were detected in 49% and Supra agger frontal cells (SAFCs) in 25% of the data sets. Suprabulla cells (SBCs) were detected in 89% and Supra bulla frontal cells (SBFCs) in 27% of the scans. Supraorbital ethmoid cells (SECs) were detectable in 9% and interfrontal septal cells in 28% of the scans. Despite a partially strong narrowing of the frontal recess, no increased occurrence of radiological sings of opacification could be detected (p > 0.05). CONCLUSIONS: Anatomical variations in the frontoethmoidal area are very common. According to the IFAC criteria, in 43% of the patients, cells could be detected with pneumatization to or into the frontal sinus. The IFAC is structured more clearly compared to previous classifications due to the anatomical aspect. It represents the most consistent classification regarding surgical planning. Further studies will demonstrate the scientific and clinical value of this classification.

Anatomical variations of anterior ethmoidal artery and their significance in endoscopic sinus surgery: a systematic review.

PURPOSE: Anterior ethmoidal artery (AEA) is at risk of injury in endoscopic sinus surgery due to its location. The aim of this review was to assess the anatomical variations of AEA and their significance. METHODS: A literature search was performed on PUBMED, SCOPUS AND EMBASE. The following keywords were used: ethmoidal artery; anterior ethmoidal artery; anterior ethmoidal canal; ethmoid sinus; ethmoid roof; skull base. The search was conducted over a period of 6 months between October 2016 and April 2017. RESULTS: 105 articles were retrieved. 76 articles which were either case reports or unrelated topics were excluded. Out of the 29 full text articles retrieved, 16 articles were selected; 3 were cadaveric dissection, 5 combined cadaveric dissection and computed tomography (CT) and the rest were of CT studies. All studies were of level III evidence and a total of 1985 arteries were studied. Its position at the skull base was influenced by the presence of supraorbital ethmoid cell (SOEC) and length of the lateral lamella of cribriform plate (LLCP). Inter population morphological variations contribute to the anatomical variations. CONCLUSIONS: The average diameter of AEA was 0.80 mm and the intranasal length was 5.82 mm. 79.2% was found between the second and third lamellae, 12.0% in the third lamella, 6% posterior to third lamella and 1.2% in the second lamella. Extra precaution should be taken in the presence of a well-pneumatized SOEC and a long LLCP as AEA tends to run freely below skull base.

Septal branches of the anterior ethmoidal artery: anatomical considerations and clinical implications in the management of refractory epistaxis.

PURPOSE: Epistaxis is a commonly presenting complaint. In severe cases, nosebleeds may occur despite antero-posterior nasal packing and often in the absence of identifiable sources of bleeding. In such cases, epistaxis may occur from septal branches of the anterior ethmoidal artery (sbAEA). The purposes of this study are to highlight the clinical role of the sbAEA in different fields of endoscopic endonasal surgery and to evaluate the efficacy and safety of their selective endoscopic endonasal ligation in the management of refractory epistaxis. METHODS: A retrospective review was performed of all patients presenting with epistaxis who underwent endoscopic endonasal coagulation of sbAEA in three Italian tertiary-care referral centers between October 2010 and October 2017. RESULTS: A total of 30 patients met the inclusion criteria. Sixteen patients had never experienced nosebleeds before, while 14 patients recalled previous epistaxes. Seventeen patients were treated under local anesthetic, while 13 required general anesthesia. No intra- or post-operative complications were observed and none of the patients received nasal packing after the procedure. In all cases the coagulation was effective in controlling the bleeding, with only two relapses in the series (2/30, 6.7%). CONCLUSIONS: The sbAEA are of great interest in endoscopic endonasal surgery, both as surgical landmarks and as feeding vessels for a variety of pedicled nasal flaps. What is more, they can be crucial for the management of refractory epistaxis. Their selective endoscopic coagulation represents an effective and safe procedure in cases of difficult-to-control epistaxis from the upper nasal fossa, with several advantages over nasal packing.

The accuracy of anatomical landmarks for locating the carotid sinus.

BACKGROUND: carotid sinus massage (CSM) is a valuable clinical test for carotid sinus syndrome (CSS) and relies on accurately locating the carotid sinus (CS). OBJECTIVE: in this study, we sought to examine the accuracy of using anatomical landmarks for locating the CS. METHODS: consecutive patients (n = 20) were recruited prospectively. Two clinicians, trained in CSM, were asked to locate the CS using anatomical landmarks. A point on the skin overlying the CS was then marked by a vascular technician using ultrasound. Accuracy of techniques was compared using intra-class correlation coefficients and Bland-Altman statistics. RESULTS: anatomical landmarks underestimated the CS location by 1.5 ± 1.3 cm. Error extremes ranged from 4 cm below to 2 cm above CS using anatomical landmarks. A moderate correlation between ultrasound and anatomical landmarks was found, r = 0.371 (P = 0.031). CONCLUSION: this is the first study to characterise the accuracy of standard anatomical landmarks used in CSM. Results suggest that the point of maximal pulsation has the lowest associated error. Future work should examine CSM yield across this and a range of other methodological factors.

Maxillary Sinus Anatomy and Physiology.

This study summaries the anatomy, including neurovascular anatomy, and physiology of the maxillary sinus. As the maxillary sinus is intimately related to the maxillary dentition, the maxillary sinus is the first paranasal sinus to become involved in infections of dental origin. Not only are these infections often very symptomatic but also spread to neighboring paranasal sinuses and extrasinus tissues such as the skin and the orbit.

A Computed Tomography (CT)-Based Observational Study of Anatomical Variations in the Sphenoid Sinus: Implications for Surgical Planning and Patient Outcomes.

INTRODUCTION:  The sphenoid sinus (SS), a paired paranasal sinus located within the sphenoid bone, is crucial in various physiological and pathological processes. Its anatomical variations are of significant interest in clinical practice, particularly in otolaryngology, neurosurgery, and radiology. This study aims to determine the anatomical variations of the SS and related structures using computed tomography (CT). MATERIALS AND METHODS: An observational study was conducted at a tertiary care center. The study included 300 patients aged 7-70 who underwent CT brain scans. Exclusions included prior sinonasal surgeries, tumors, nasal polyposis, recurrent pituitary lesions, head trauma, and past orbital or cranial surgeries. Three-dimensional reconstructions assessed SS dimensions, pneumatization types, and variations in the internal carotid artery and optic nerve. RESULTS: A study on the types of SSs revealed that the reseller type is the most common, accounting for 45% of cases (135 instances). The sellar type accounts for 36% (110 instances), while the conchal type is the least common, observed in 18.33% of cases (55 instances). A significant association between the SS type and variations between neurovascular structures was seen, which was confirmed using chi-square tests. There was a statistically significant relationship between carotid artery variations and SS, with the normal course being predominant at 200 individuals (73.33%). Approximately 40 cases (13.33%) present with dehiscence through the sinus, while 30 individuals (10%) show close proximity. Other, less common variations are observed in 10 patients (3.33%). Optic nerve variations displayed distinct frequencies, with the normal course prevailing in 250 cases (83.33%). Approximately 30 cases (10%) exhibit close proximity to surrounding structures, while 15 cases (5%) present with dehiscence through the sinus. Other less common optic nerve variations are observed in five patients (1.67%). CONCLUSION:  Comprehensive knowledge of SS anatomy through CT scans is essential for enhancing surgical outcomes and ensuring patient safety.

Impact of long-term nasal airflow deprivation on sinonasal structures and chronic rhinosinusitis in total laryngectomy patients.

Objective: Total laryngectomy (TL) patients are good models in which to evaluate the effects of nasal airflow cessation on the sinonasal tract. Here, we evaluated changes in sinonasal structures and association with sinus opacification in the computed tomography (CT) images 3 years post-TL. Methods: Patients who underwent TL from 2005 to 2017 in a teaching academic center were reviewed retrospectively. Patients with a final follow-up CT taken less than 3 years after TL, tracheoesophageal puncture, inadequate CT image, or history of sinonasal surgery were excluded. The control group included patients who underwent a partial laryngectomy or hypopharyngectomy without requiring a tracheotomy for more than a month. Altogether, 45 TL patients and 38 controls were selected. The volume of all four paranasal sinuses, inferior turbinate soft tissue volume (ITSTV), maxillary sinus natural ostium (MSNO) mucosal width, and Lund-Mackay scores (LMS) were measured on preoperative and postoperative CT scans. Results: The mean duration between surgery and the final CT scan was 6.3 ± 2.4 and 5.5 ± 2.3 years for the TL and control groups, respectively. Neither group showed significant changes in the four paranasal sinuses' volume or MSNO mucosa width. The ITSTV decreased significantly, from 4.6 ± 1.3 to 2.8 ± 1.1 mL (p < .001), in the TL group, regardless of the presence of nasal septal deviation, showing ITSTV reduction on both concave and convex sides. By contrast, the control group showed no significant changes in ITSTV. Postoperative LMS changes in both groups were insignificant. The number of patients with LMS aggravation or alleviation was the same in both groups, regardless of preoperative sinus opacification. Conclusions: Paranasal sinus structures and sinus opacification are not affected significantly by nasal airflow cessation; however, the inferior turbinate mucosa is affected by long-term discontinuation of nasal airflow. Level of Evidence: 4 (case-control study).

A Consistent Endoscopic Landmark to Identify the Anterior Ethmoidal Artery.

OBJECTIVE: The anterior ethmoidal artery (AEA) is an important structure to identify during endoscopic sinus surgery. Although identification on imaging is easily taught, a consistent endoscopic landmark for the AEA, independent of anatomic ethmoid cell variation, is lacking, leaving many surgeons unclear about the exact location without dependence on navigation. Here, we describe a consistent endoscopic landmark, regardless of anatomical ethmoid variation. METHODS: We prospectively enrolled adult patients undergoing endoscopic surgery involving frontal and ethmoid sinuses in this observational study. The AEA landmark was defined simply as the septation or ridge one step back along the ethmoid skull base from the posterior table of the frontal sinus. The gold standard to calculate the sensitivity of our endoscopic landmark was an image-navigation system, registered to within 1.5 mm accuracy, locating the AEA within three planes. Both endoscopic and computerized tomography (CT) images of the pointer at the landmark were taken simultaneously. The concordance of endoscopic to navigation images was independently assessed by three blinded rhinologists. RESULTS: Forty patients were included in our study with 73 sides analyzed. Diagnoses included chronic rhinosinusitis without polyps (52.5%), with polyps (22.5%), recurrent acute sinusitis (15%), sinonasal tumors (7.5%), and odontogenic sinusitis (2.5%). The AEA was accurately identified using our endoscopic landmark in 97.3% of the cases (71/73). Of the two cases in which the AEA was not found within the landmark, the artery was located ≤1 mm posteriorly. CONCLUSION: We describe a consistent endoscopic landmark to identify the AEA, conserved across various clinical diagnoses and anatomic variations in sinus structure. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:1096-1099, 2024.

Anatomic Relationship Between the Head of the Middle Turbinate and First Olfactory Filum: A Radiographic Assessment.

BACKGROUND: The endoscopic modified Lothrop procedure (EMLP) has become a frequently utilized procedure in rhinologic surgery. One of the most serious complications of the procedure is cerebrospinal fluid leak, which may occur due to lack of recognition of the anterior skull base in the region of the first olfactory filum (FOF), or direct injury to the FOF itself. OBJECTIVES: To evaluate the position of the head of the middle turbinate (MT) relative to the FOF, which is an important landmark in the EMLP. METHODS: A series of previously obtained patient computed tomography scans of the sinus were reviewed. A reproducible process was implemented to obtain the measurements. First, the FOF was identified on an axial series. Using a localization feature of the radiographic software, this anteroposterior (AP) position could be visualized in a coronal plane. Subsequently, the MT was viewed in a sagittal plane, where a measurement between the head of the MT and the AP position of the FOF could be performed. RESULTS: The AP distance between the head of the MT and the FOF was measured in 92 patients. The head of the MT was either at or anterior to the FOF in all measured subjects. The mean anterior distance of the head of the MT to FOF was 3.6 mm (±2.4 mm) on the right, and 3.8 mm (±2.2 mm) on the left. The range in AP distance was 0 to 12 mm. There was no significant difference in AP distance between the head of the MT and FOF based on gender (P = .413) or diagnosis (P = .254). CONCLUSIONS: In our study, the head of the MT was reliably at or anterior to the FOF in all subjects, suggesting its utility as a fixed landmark in endoscopic sinus surgery, particularly in the EMLP. LEVEL OF EVIDENCE: N/A.

Anatomical variations of interest for posterior nasal nerve cryotherapy in the treatment of chronic rhinitis: A radioanatomic study.

KEY POINTS: An unfavorable insertion of the middle turbinate for cryotherapy was present in 74.2% of cases. Placing cryoprobe 15-30 mm above the nasal floor targets the nerves in 95.8% of cases. Centering the cryoprobe 38 mm behind the inferior turbinate axilla targets the nerves in 94.6% of cases.

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.

Cell Type Catalog of Middle Turbinate Epithelium (Cell Catalog of Turbinate Epithelium).

Objective: Single-cell RNA-sequencing of middle turbinate mucosa was performed to create the first single-cell transcriptome catalog of this part of the human body. Study Design: Basic science research. Setting: Single center, tertiary care center. Methods: Samples were obtained from the head of the middle turbinate from a healthy volunteer. After the specimen was prepared per lab protocol, cells were dissociated, resuspended, and counted. Single-cell libraries were then prepared according to the 10x Genomics protocol and sequenced using NovaSeq 6000 (Illumina). Sequencing data were processed using Cell Ranger, and clustering and gene expression analysis was performed using Seurat. Cell types were annotated through expression profiling of single cells using known markers and data from other single-cell studies. Results: Fourteen unique cell types were identified, including serous, goblet, club, basal, ciliated, endothelial, and mesenchymal cells, as well as multiple types of blood cells. Conclusion: This catalog provides a comprehensive depiction of the cellular composition of middle turbinate mucosa. By uncovering the cellular stratification of gene expression profiles in the healthy middle turbinate epithelium, the groundwork has been laid for further investigation into the molecular pathogenesis and targeted therapy of sinonasal disease.

Development of an optimized preoperative computed tomography imaging checklist for endoscopic sinus surgery utilizing a systematic review of the literature and the modified Delphi method.

BACKGROUND: Critical review of computed tomography (CT) imaging is essential in preoperative planning for endoscopic sinus surgery. In this study, we used a systematic review and a modified Delphi method to develop a comprehensive checklist that facilitates preoperative review of sinus CT imaging. METHODS: We performed a systematic review of PubMed, Embase, CINAHL, Cochrane, and Web of Science databases to identify existing checklists developed to evaluate sinus CT imaging. An inclusive list of items from these checklists was compiled and a modified Delphi methodology was used to assign ranked priority. The Delphi process involved 14 rhinologists and had three phases: an initial survey with Likert priority (scale of 1-9) and two rounds of live discussions followed by survey to confirm consensus. RESULTS: Ninety-seven possible checklist items were identified from a systematic review and panelist input. On initial survey, 63 items reached a consensus score of 7+, and 13 items had near consensus scores between 6 and 7; two of these 13 borderline items were retained after subsequent panelist discussion. The resulting items were consolidated into an 11-item disease checklist and a 24-item anatomical checklist; the anatomical checklist was further divided into six subsections: nasal cavity, maxillary, ethmoid, sphenoid, frontal, skull base, and orbit. Additionally, panelists identified six core aspects of patient history to consider prior to surgery. CONCLUSIONS: After establishing content validity through a systematic literature review and a modified Delphi method, we developed a comprehensive checklist for preoperative sinus CT imaging review; implementation and evaluation of validity among trainees will suggest overall utility.

Biological sex as a modulator in rhinologic anatomy, physiology, and pathology: A scoping review.

BACKGROUND: Biological sex is increasingly recognized as a critical variable in health care. The authors reviewed the current literature regarding sex-based differences in rhinology to summarize the data and identify critical knowledge gaps. METHODS: A scoping review was conducted. Publications reporting sex-based differences in anatomy, physiology, and pathology focusing on disease prevalence, disease burden, and outcomes in rhinology were identified. RESULTS: Seventy-five relevant manuscripts were identified. While paranasal sinuses are of similar size at birth, they become larger in males leading to differences in ostium location. Females outperform males in olfactory identification but only in the 18- to 50-year age group. Estrogen and progesterone administration can impact muscarinic and α1 -adrenergic nasal mucosa receptor density. Chronic rhinosinusitis (CRS) and CRS without nasal polyps are more prevalent in females while CRS with nasal polyps is more prevalent in males. CRS symptom burden is higher in females before and after endoscopic sinus surgery; however, no difference in endoscopic sinus surgery utilization was found based on sex. Allergic rhinitis is more common in males before puberty and in females after puberty. Epistaxis is more prevalent in males and postmenopausal females compared with premenopausal females, perhaps from differences in sex-hormonal and hypertension status. In nasopharyngeal carcinoma, the incidence of sinus abnormalities was higher in males than females. CONCLUSIONS: Although many sex-based differences exist in rhinology, further research is necessary to offer evidence-based treatment guidelines. Gonadal hormones should be studied as a therapeutic in rhinologic pathology as baseline physiologic differences exist such as those found in nasal mucosa receptor density.