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A patient in his 20s presented with a change in the appearance of his left eye with evidence of relative afferent pupillary defect. Imaging revealed a giant frontoethmoidal osteoma, a benign sinonasal tumour, invading three-quarters of the orbit. Multidisciplinary discussion involving opthalmology, maxillofacial surgery, neurosurgery and otolaryngology resulted in the decision to attempt entirely endoscopic excision of this lesion, which was performed with successful outcomes. This case demonstrates how a sinonasal osteoma should be considered in the differential diagnosis for a patient presenting with proptosis or other eye signs suggestive of compression of the orbital compartment. This case report and literature review highlights the possibility of managing giant sinonasal osteomas with orbital extension through a completely endoscopic approach., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: The anterior ethmoidal artery (AEA) is an important risk area in endoscopic sinus surgery. This study aimed to evaluate the course of AEA according to the Keros classification and the presence of supraorbital ethmoid cell (SOEC) and to prevent possible complications by emphasizing the importance of preoperative paranasal computed tomography (CT) imaging. This approach will increase the effectiveness of endoscopic sinus surgery and improve patient safety., Methods: The paranasal CT scan images of patients aged > 18 years between October 2020 and November 2021 from our center were retrospectively analyzed. The images were primarily evaluated in the coronal plane, and the sagittal and axial planes were utilized to evaluate variations in AEA regarding the skull base. Furthermore, the relation of AEA course with Keros classification and SOEC was evaluated. The study included 1000 patients aged 18-80 years (right and left, a total of 2000 samples)., Results: Grade 3 AEA was the most common regarding the skull base. Keros Type 2 was the most common classification. Overall, 48.7% patients had SOEC. The incidence of Grade 3 AEA was higher among patients with SOEC and a higher Keros classification compared with those without SOEC and a lower Keros classification. Furthermore, Keros Type 3 was the most associated with SOEC presence., Conclusion: Consistent with the literature, the probability of Grade 3 AEA in patients with high Keros classification and SOEC was significantly higher in our study. Therefore, we consider that preoperative imaging according to Keros classification and SOEC presence can predict AEA course and guide surgery., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Correction of the crooked nose, especially the perpendicular plate of the ethmoid bone, has the potential to cause skull base injury. At present, the safe and effective method for perpendicular plate resection has not been clearly defined through biomechanics., Method: CT scan data of 48 patients with crooked nose and deviated nasal septum were divided into C-type, angular deformity-type, and S-type based on the morphology of the 3D model. Different types of finite element models of the nasal bony septum and skull base were established. The osteotomy depth, angle, and force mode of the PPE resection were simulated by assembling different working conditions for the models. The von Mises stress of the anterior cranial fossa was observed., Results: When the osteotomy line length was 0.5 cm, the angle was at 30° to the Frankfurt plane, and 50 N·mm torque was applied, the von Mises stress of the skull base was minimal in the four models, showing 0.049 MPa (C-type), 0.082 MPa (S-type), 0.128 MPa (angular deformity-type), and 0.021 MPa (control model). The maximum von Mises stress values were found at the skull base when the osteotomy line was 1.5 cm, the angle was 50°, and the force was 10 N along the X-axis, showing 0.349 MPa (C-type), 0.698 MPa (S-type), 0.451 MPa (angular deformity-type), and 0.149 MPa (control model)., Conclusion: The use of smaller resection angle with the Frankfurt plane, conservative resection depth, and torsion force can better reduce the stress value at the skull base and reduce the risk of basicranial fracture. It is a safe and effective technique for perpendicular plate resection of the ethmoid bone in the correction of crooked nose., Level of Evidence Iv: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Background: Ethmoidal arteries are at risk of accidental injury during endoscopic sinus surgery (ESS)., Aims/objectives: We aimed to examine the location of ethmoidal arteries in relation to ethmoid cells and the anterior skull base (ASB) in Japanese patients., Material and Methods: CT images of 100 sides of 50 patients were retrospectively reviewed. The location of anterior ethmoidal arteries (AEAs), middle ethmoidal arteries (MEAs) and posterior ethmoidal arteries (PEAs) in relation to ethmoidal cells and their distance from the ASB were evaluated., Results: AEAs and PEAs were present in all sides. 60% of AEAs and 9% of PEAs ran below the level of ASB. MEAs were present in 21 sides and ran below the ASB in 23.8% (5/21) of these sides. The incidence of AEAs running below the level of ASB was significantly higher in the sides with supraorbital ethmoid cells (SOECs) than in those without SOECs., Conclusion and Significance: This study revealed the position and the distance from ASB of AEAs, PEAs, and MEAs in relation to ethmoid cells in Japanese patients. In cases with SOECs, surgeons should be careful not to injure the AEAs running below the level of ASB. J. Med. Invest. 71 : 273-278, August, 2024.

Purpose: Understanding ethmoid roof morphology is crucial to prevent complications in endoscopic sinus surgery. This study aimed to evaluate the morphological properties of the ethmoidal roof regarding gender and age differences using Keros and Yenigun classifications on high-resolution computed tomography images., Methods: We retrospectively analyzed 891 high-resolution computed tomography paranasal sinus study images and measured the depth of the cribriform plate in coronal sections and the anterior-posterior length in axial planes. The study retrospectively examined CT images of paranasal sinuses of patients living in the eastern Anatolian region of Turkey., Results: In both Keros and Yenigun Classifications, the most common class was type 2, and the least common class was type 3. According to Keros et al.'s method, no significant difference was observed between men and women (p = 0.698). However, according to Yenigun et al., the average values of women in terms of the anterior-posterior distance of the ethmoid roof were significantly higher than men (p = 0.001). When examined according to age, a very low, negative correlation was revealed regarding Keros and Yenigun classifications (p = 0.047 and p < 0.001 retrospectively). According to Keros and Yenigun's classification, there was no significant difference between the left and right sides (p = 0.488 and p = 0.919, respectively)., Conclusion: The morphological properties of the ethmoidal roof have importance to be considered for preoperative planning. Studying larger patient groups and meta-analyses that gather various research results about this subject might help better understand the ethmoidal roof morphology among populations., (© 2023. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Progress in skull-base endoscopic surgery has improved our knowledge of olfactory cleft (OC) anatomy. This article presents a review of current knowledge concerning the OC roof: descriptive anatomy, radiological exploration, and endoscopic observation. The OC is a narrow area in the most superior part of the nasal cavity. Its roof is the thinnest structure separating the nasal cavities from the brain; it comprises three superimposed tissues: nasal mucosa, ethmoid cribriform plate (ECP), and dura mater. The ECP comprises the anterior ECP containing the ethmoidal slit (ES) medially and the cribroethmoidal foramen (CEF) laterally; and the posterior ECP, comprising the olfactory foramina. The OC roof is bordered anteriorly by the nasal bone roof, laterally by the lateral ethmoid masses, and posteriorly by the jugum and anterior wall of the sphenoid sinuses. Imaging is crucial for analyzing this wall, providing precise detailed information on conformation and anatomic relations with adjacent structures such as the anterior ethmoidal artery. Understanding OC roof anatomy and correct interpretation of imaging are essential for safety in present-day functional endoscopic sinus surgery and anterior skull-base oncologic surgery., (Copyright © 2023. Published by Elsevier Masson SAS.)

The cribriform plate and attachment area of the middle turbinate are anatomical structures that may potentially be injured during septoplasty and/or endoscopic sinus surgery. The purpose of this study is to compare the cribriform plate and middle turbinate length dimensions between patients with vomer agenesis (VA) and the control group using paranasal sinus computed tomography (CT). Paranasal sinus CTs performed in our hospital between January 2011 and January 2021 were evaluated and patients with VA were identified. A control group was created from patients who underwent paranasal sinus CT for various reasons during the same date interval. The cribriform plate and middle turbinate lengths were statistically compared between the groups. A total of 10,095 paranasal sinus CTs were evaluated and 54 patients with VA were identified. Seven patients with VA were excluded from the study because their measurements could not be made accurately. Forty-seven VA patients were included in the study group, while 94 patients were included in the control group. There was no statistical difference in cribriform plate dimensions (medial ethmoid roof plate height, cribriform plate height, cribriform plate lateral lamella height and width) between the groups (for all dimensions P >0.05). The middle turbinate length was significantly higher in the VA group (for right and left P =0.020 and 0.011, respectively). These findings theoretically suggest that the risk of cribriform plate injury during septoplasty and/or endoscopic sinus surgery is similar in patients with or without VA., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)

Objectives: We investigated supraorbital ethmoid cell (SOEC) presence and types in paranasal sinus computed tomography (PNSCT)., Methods: The PNSCT images of 188 adult patients (93 males and 95 females) were evaluated as SOEC group (n = 87 sides), and non-SOEC group (n = 289 sides, control). In both groups, anterior ethmoid artery (AEA) notch-ethmoid roof distance and presence of AEA canal were evaluated. In the SOEC group, SOEC types (type 1 to 3) and SOEC angle are also examined., Results: SOEC was detected in 87 sides (23.13 %). SOEC type 2 was the most detected type (71.3 %). AEA notch-ethmoid roof distance of the SOEC group was significantly higher than those in the non-SOEC group. AEA notch-ethmoid roof distance of the SOEC Type 3 group was significantly higher than SOEC Type 2 group. AEA notch-ethmoid roof distance was 3.74 ± 1.81 mm in the SOEC group and 0.68 ± 1.16 mm in the non-SOEC group. When SOEC types were considered, this distance was 5.29 ± 2.66 mm in type 3, 3.35 ± 1.35 mm in type 2 and 3.48 ± 0.92 mm in type 1. In higher SOEC types, SOEC angle; and AEA notch-ethmoid roof distance increased., Conclusion: In more pneumatized SOEC presence, SOEC angle increase, and AEA notch-ethmoid roof distance increases, AEA runs inferiorly in the ethmoid cells and freely below the skull base; and is more susceptible to injury. The surgeons should be more careful not to damage AEA in the FESS when detecting well-pneumatized SOECs (SOEC Type 3)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: To compare two types of CT acquisition parameters: CT scan of the facial bone and CT scan of the sinuses, for studying the ethmoidal slit and its relationship with the frontal sinus and anterior ethmoidal artery., Materials and Methods: Retrospective study of 145 scans of the sinuses and 79 of the facial bones performed between 2012 and 2016. On each scan, the visibility of the ethmoidal slits, their length, their distance from the ethmoidal artery, and their relationship with the anterior and posterior wall of the frontal sinus were studied., Results: The ethmoidal slit was better visualized on CT scans of the facial bone (58.2%) than on those of the sinuses (43.1%) (p = 0.02). The distance between the anterior ethmoidal artery and the anterior part of the cribriform plate was 9.3 mm for CT scans of the facial bone and 8.4 mm for CT scans of the sinuses. The theoretical risk of damaging the glabellar soft tissue and that of damaging the meninges during a frontal sinusotomy was evaluated, respectively, at 9.6% and 26.1% for CT scans of the facial bone, and at 6.2% and 21.5% for sinus scans., Conclusions: CT scans of the facial bone are better than CT scans of the sinuses for identifying ethmoidal slits and their distance from the canal of the anterior ethmoidal artery. The identification of these elements is relevant for the surgeon during frontal sinus surgery and makes it possible to assess the risk of damaging the glabellar soft tissue or meninges. Performing a CT scan of the facial bone seems preferable to that of a CT scan of the sinuses in certain pathological situations, such as cerebrospinal rhinorrhea or revision surgeries of the frontal sinus., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To perform endoscopic sinus surgery safely and effectively, surgeons need to visualize the complex anatomy of the anterior ethmoid and frontal sinus region. Because this anatomy is so variable and individualized, the foundation of understanding lies in identifying, following, and visualizing the drainage pathway patterns and anticipating possible variations., Methods: We studied 100 sides (50 cases: 22 male, 28 female, aged 12-86, average age 46.5 years, ± 19.5) using computed tomography (CT) and multiplanar reconstruction (MPR) to identify and classify the drainage pathways leading to the frontal sinus and anterior ethmoidal cells., Results: Analysis revealed five patterns of drainage pathways defined by their bony walls: between the uncinate process and the lamina papyracea [UP-LP]; between the uncinate process and the middle turbinate [UP-MT]; between the uncinate process and the accessory uncinate process [UP-UPa]; between the uncinate process and the basal lamella of the ethmoidal bulla [UP-BLEB]; and between the basal lamella of the ethmoidal bulla and the basal lamella of the middle turbinate [BLEB-BLMT]. In most cases, BLEB formed the posterior wall of the drainage pathway of the frontal sinus, indicating BLEB could be one of the most important landmarks for approaching the frontal sinus., Conclusions: As endoscopic sinus surgery depends on an understanding of this anatomy, this study may help surgeons to identify and follow the drainage pathways more accurately and safely through the anterior ethmoid to the frontal sinus., (© 2022. The Author(s).)

Background: To investigate the anatomical imaging characteristics of supraseptal posterior ethmoid cells (SPEC)., Materials and Methods: Paranasal sinus computed tomography scans of 153 inpatients from February 2019 to September 2021 were reviewed, and the anatomical characteristics of SPEC in the scans were collected., Results: Supraseptal posterior ethmoid cells are posterior ethmoid (PE) cells extending medially and superiorly to the posterior superior of the nasal septum and into the sphenoid body but not close to the optic canal. The SPEC, Onodi cell, and sphenoidal sinus (SS) may appear in the posterior superior of the nasal septum, but the occurrence rate of the SPEC (5.88%; 9/153 cases) was significantly lower than that of the SS (22.88%) and Onodi cell (21.57%). The anterior SPEC is adjacent to the cribriform plate, the perpendicular plate of the ethmoid bone and the posterior ethmoidal artery (PEA). The posterior SPEC is adjacent to the SS and PE (6/9 cases), the SS and Onodi cell (2/9 cases) or the PE only (1/9 cases)., Conclusions: The SPEC is a rare pneumatization that occurs in the posterior superior area of the nasal septum. Care should be taken to protect the skull base, cribriform plate and PEA when opening the SPEC during endoscopic sinus surgery.

Objective: To reveal the anatomical relationships of the ethmoid roof on CT in pediatric case group., Methods: We measured the depth of olfactory fossa (DOF), the width of olfactory fossa (WOF), the angle between lateral lamella and cribriform plate (LLCPA), the width of the olfactory cleft (WOC), the length of lateral lamella (LLL), orbital roof fovea to ethmoidal distance (ORFED) and orbital roof to cribriform plate distance (ORCPD) and we determined Keros and LLCPA types from paranasal sinus CT of subjects under 16 years of age retrospectively., Results: The incidence of Keros type I was higher in females and Keros Type II in males. The ORCPD, DOF and LLL values were found to be higher in 13-16 years age group and WOF and LLCPA in 4-6 years age group. The prevalence of Keros type II was higher in the 13-16 age group, and Keros type I was higher in other age groups. LLCPA type A was the most frequent in all age groups and in both sexes. There was a positive correlation between age and ORCPD, DOF, LLL, and a negative correlation with ORFED, WOF, LLCPA. Olfactory fossa width and depth had a negative correlation. LLCPA had a positive correlation with WOF and a negative correlation with DOF. There was a positive correlation between LLCPA and LLL. DOF and LLL had a positive correlation too., Conclusions: Paranasal sinus CT provides useful information about frontal skull base anatomic relations before sinus surgery in pediatric cases., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Background: Surgery to anterior skull base is challenging since complex structures are involved. Injury of olfactory fila and optic nerve may result in postoperative complications. In our study, the authors aim to use computer topographic image to provide a comprehensive anatomical information of anterior skull base and set up a new classification of optic canal (OC) in ethmoid sinus by the degree of bony defect, so as to help surgeons in endoscopic transnasal approach to anterior skull base., Method: Computer topographic angiography images of 112 individuals were reviewed, the measurement was performed on coronal, sagittal, and axis planes after the multiplanar reformation. Nostril and mid-sagittal lines were used to locate the anterior, middle, and posterior part of ethmoidal foramina and orbital opening of OC. Further, the authors classified OC in ethmoidal sinus into 4 types by the degree of the bony defect., Result: Distance between nostril to anterior, middle, and posterior part of ethmoidal foramina and OC are 6.23 ± 0.21, 6.62 ± 0.26, 7.29 ± 0.25, and 7.76 ± 0.41 mm, respectively. Angle between line from nostril to ethmoidal foramina and horizontal plane are 47.50° ± 1.03°, 41.67° ± 1.33°, 37.20° ± 1.34°, respectively. For the 4 types of OC, the percentage is 15.6%, 11.6%, 31.3%, and 41.5%, respectively., Conclusions: Our findings provide anatomical information of ethmoidal foramina and OC during endoscopic transnasal approach to anterior skull base, on the basis of some fixed anatomical landmarks. So as to enhance the surgical safety of this procedure and aid in the choice of the appropriate endoscopic equipment for the procedure., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 by Mutaz B. Habal, MD.)

Objectives: This study investigated the visualization of the anterior ethmoidal artery (AEA) as notch, canal and sulcus, its relationship between supraorbital ethmoid cells (SOECs) and the Keros classification of the olfactory fossa on paranasal sinus computerized tomography (PNSCT)., Methods: In this retrospective study, the paranasal sinus computerized tomography (PNsCT) images of 204 patients (103 males and 101 females) were analyzed. AEA canal, notch and sulcus, SOECs, the distance between AEA notch and ethmoid roof, AEA canal angle and Keros classification of the olfactory fossa were evaluated., Results: AEA notch in all patients and AEA canal (37.6 to 45.6%) and AEA sulcus (53.5 to 61.2%) were visualized. In the AEC canal and sulcus visualized patients, the Keros classification revealed higher. AEA notch and ethmoid roof distance increased in patients with higher Keros types. The presence of SOECs was significantly higher in males (41.7%) than females (19.8%) on the left side. There was a positive correlation between SOEC presence and Keros classification. In patients with SOEC, bilateral AEA canal and sulcus visualized more; and bilateral AEA notch and ethmoid roof distance increased. On the right side, the AEA canal angle of the males was significantly higher than that of the females. In patients with SOEC, the left AEA canal angle also increased., Conclusion: When detected SOECs and higher Keros types, the AEA was detected away from the skull base, AEA notch-ethmoid roof distance increased; and the AEA canal angle increased. To avoid intracranial penetrations, PNSCT should be evaluated carefully during the preoperative period., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: The aims of this study are to determine the incidence and more frequent localizations of orbital fat tissue herniation accompanying dehiscences in the medial orbital wall and to investigate the relationship between orbital fat tissue herniations and the anterior and posterior ethmoidal foramina., Methods: One thousand two hundred patients who had undergone computed tomography with a preliminary diagnosis of sinusitis and who had no previous facial, orbital, paranasal sinus surgeries or history of trauma were retrospectively analyzed. The localization of the ethmoidal foramina and orbital fat tissue herniations were marked. In patients with orbital fat tissue herniation, the relationship between the localization of orbital fat tissue herniation and the anterior and posterior ethmoidal foramina was investigated., Results: The incidence of orbital adipose tissue herniation in our study was 7.9%. Of the 98 herniations on the bilateral medial orbital wall, 60 were in zone 3, and the most common herniation site was zone 3. A statistically significant difference was noted between the localization zone of the anterior ethmoidal foramen and the localization zones of orbital fat tissue herniations (Fisher's exact test, p < 0.001)., Discussion: Zone 3 is the weakest area of the medial orbital wall, and zone 3 is the most prone to herniation of fat tissue. The association of orbital fat tissue herniations with the anterior ethmoidal foramen is extremely common. Being cognizant of this finding may help a surgeon better estimate the anatomical view to be met before functional endoscopic sinus surgery as well as to minimize the risk of possible orbital complications, especially anterior ethmoidal artery injury.

(1) Background: For good surgical performance, sound knowledge of anatomy is required. Although the ethmoid air cells and sphenoid sinuses are subject to a high degree of variation, their possible extensions above the nasal fossa at the posterior end of the cribriform plate of the ethmoid bone (CPEB) were seemingly overlooked. (2) Methods: We retrospectively studied 162 case files from 55 male and 107 female cases, with ages varying from 42 to 80, which were scanned using Cone Beam Computed Tomography. (3) Results: In 56.17% of cases, an unpneumatized CPEB (type I) was found. Nasal roof recesses of ethmoidal origin (type II) were found at the posterior end of the CPEB in 20.37% of cases. Different types of sphenoidal pneumatizations of the posterior end of the CPEB (type III) were found in 22.83% of the cases. Onodi cells projected nasal roof recesses (type IV) in only 10 cases. In all types, nasal roof recesses were found either above the CPEB or within/underneath it. Moreover, such nasal roof recesses were found to be either unilateral, extended contralaterally, or bilateral. (4) Conclusions: As such recesses of the posterior CPEB, previously overlooked, belong to the posterior rhinobase, they should be carefully documented preoperatively to avoid unwanted surgical damage to the olfactory bulb or CSF fistula.

Abstract: Position of anterior ethmoidal artery and height of lateral lamella of cribriform plate (LLCP) represent critical variants in endoscopy.In 200 maxillofacial computed tomography scans of patients the position of anterior ethmoidal foramen (AEF) in relation to ethmoid roof was recorded. The height of LLCP was measured and classified according to Keros classification.Differences in AEF position and distribution of Keros types, and LLCP height according to sex were assessed through chi-square test (P < 0.05) and 1-way analysis of covariance (ANCOVA) test, respectively (P < 0.05). Differences in LLCP height according to different AEF position were assessed through Mann-Whitney test (P < 0.05).No differences were observed in prevalence of AEF exposure according to sex (P > 0.05); LLCP height was higher in males than in females, with a higher frequency of Keros type 3 (P < 0.05). Moreover, subjects with AEF exposure had a significantly higher LLCP height (P < 0.01).Results highlighted innovative data useful for improving the knowledge of these sensitive variants., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 by Mutaz B. Habal, MD.)

Objective: To investigate the association of high septal deviation with the olfactory fossa depth and Gera angle., Methods: Fifty-four computed tomography scans of patients with high septal deviation were evaluated. The olfactory fossa depth and Gera angle were measured. The values of the deviated and nondeviated sides were compared., Results: No association between high septal deviation and the olfactory fossa depth and Gera angle was found., Conclusion: High septal deviation does not affect the olfactory fossa depth and Gera angle. In other words, the olfactory fossa depth and Gera angle have no association with the high septal deviation.

Background: Recent developments in endoscopic sinus surgery (ESS) have increased the need to investigate the complex anatomic variations in the ethmoid roof and skull base, to inform the surgeon about the risk of damaging these crucial areas during ESS., Objective: To offer a detailed description of sinus anatomy focusing on the key surgical landmarks in ESS and frontal recess surgery to standardize a systematic approach during the preoperative sinuses imaging evaluation. Methodology: A total of 220 computed tomography (CT) scans were reviewed to obtain six sets of measurements: the depth of the cribriform plate (CP); the length of the lateral lamella of the cribriform plate (LLCP); the angle formed by the LLCP and the continuation of the horizontal plane passing through the CP; the position of the anterior ethmoidal artery (AEA) at the skull base; the extent of frontal sinus pneumatization (FSP); the type of superior attachment of the uncinate process (SAUP)., Results: The length of the LLCP was statistically significantly correlated with the different Keros classification types, the angle formed by the LLCP with the continuation of the horizontal plane passing through the CP, and with the AEA position at the skull base. The depth of the olfactory fossa was correlated with FSP., Conclusions: According to the Keros and Gera classifications, the data obtained from these evaluations allow the assessment of anatomic-radiological risk profiles and can help identify those patients who are high risk for ethmoid roof injury.

A precise nomenclature and terminology is the foundation of communication in Anatomy and related biomedical sciences. The olfactory bulbs and nerves lie above and below the cribriform plate (CP), respectively. Hence, many anatomical landmarks in this region have names adopting the term "olfactory" as qualifiers. Ambiguous use of these "olfactory" terms exists, with some potential repercussions on patient treatments. We performed a publication database analysis to determine the frequency of misuse of names for seven anatomical "olfactory" spaces close to the CP and nasal cavity. We searched PubMed® publications having the keyword "olfactory" in their title or abstract, plus one of seven other keywords: "groove", "fossa", "recess", "cleft", "vestibule", "sulcus", and "cistern". We reviewed all abstracts for accuracy of these terms relative to accepted norms or customary definitions. By February 2020, we found all these keywords in 1255 articles. For the terms olfactory "groove" and "fossa", the number of relevant articles (and percentage of those inaccurately using these terms) were 374 (1.1%), and 49 (8.2%), respectively. All 52 abstracts containing "olfactory" and "vestibule" were irrelevant, relating to the "nasal vestibule" and olfactory function, instead of "olfactory vestibule". Overall, terms used to describe "olfactory" spaces near the CP are seldom ambiguous or inaccurate, but the terms olfactory "groove" and "fossa" are occasionally misused, We propose several new "olfactory" terms for inclusion in the Terminologia Anatomica, and stress the need for uniform nomenclature leading to greater consistency and accuracy in clinical use of anatomical terms containing the word "olfactory" as a descriptor., (© 2021 American Association of Clinical Anatomists.)

It is proposed to delineate the anatomo-clinical target volumes of primary tumor (CTV-P) in ethmoid cancers treated with post-operative radiotherapy. This concept is based on the use of radioanatomy and the natural history of cancer. It is supported by the repositioning of the planning scanner with preoperative imaging for the replacement of the initial GTV and the creation of margins around it extended to the microscopic risk zones according to the anatomical concept. This article does not discuss the indications of external radiotherapy but specifies the volumes to be delineated if radiotherapy is considered., (Copyright © 2020. Published by Elsevier Masson SAS.)

Extracranial manifestation of arteriovenous malformations (AVMs) is uncommon. Nasoseptal AVMs are an even rarer entity. In this case report, we present an interesting and first-of-its-kind case of the development of a left nasoseptal AVM in a 60-year-old man after a fall. This was likely post-traumatic, unlike the usual congenital AVMs described in the literature. The patient was managed conservatively with regular follow-up for the AVM as he was asymptomatic., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

The article provides an overview of foreign and domestic studies on the anatomy of the medial wall of the orbit. Possible structural variants of the osseus structures of the medial wall and their applied clinical significance are indicated, including those having individual occurrence: additional lacrimal bone, morphological features of the structure of the fossa of the lacrimal sac, location, shape and size of the cells of the ethmoid bone, Onody cells, Haller infraorbital cell, the relative position of the anterior and posterior ethmoid foramina, the presence of additional ethmoid foramina, dysgenesis of the lacrimal bone and the orbital plate of the ethmoid bone. The anatomical prerequisites for the occurrence of intraoperative complications with surgical access to the medial wall of the orbit are described.

Dog owners are often impressed by their dog's sense of smell. Many of these dogs, however, have skulls that are quite altered from those of their closest canid relatives. Housed within these skulls are essential olfactory structures like the cribriform plate that play a role in olfaction and the transmission of olfactory nerve impulses to the olfactory bulb of the brain. With improvements in CT technology and accessibility, we are now able to digitally reconstruct in 3D cribriform plate morphology and study its variation within and among species. In this study, we CT scanned the skulls of 95 dog specimens from 45 different domestic dog breeds and 12 species of wild canid and compared the shape of the cribriform plate among three main groups: domestic dog breeds, wolf-like canids, and fox-like canids. Despite only recent selective pressure for extreme skull morphology, domestic dogs display much more variation in cribriform plate shape than wild canids, indicating that cribriform plate shape is plastic and linked to skull shape. Intense artificial selection on domestic dog skull phenotype in the last 200 years has clear effects on secondary features of the domestic dog skull, implying that selection for overt phenotypes also can impact other anatomical features associated with the skull, like the cribriform plate., (© 2020 American Association for Anatomy.)

Objectives: This study investigated morphological variations of lamina papyracea, the structure that should be carefully considered when opening posterior ethmoid sinus during endoscopic sinus surgery, to avoid injury., Study Design: This study employed axial, coronal, and sagittal computed tomography., Methods: Using computed tomography images of 228 face-sides, various anatomical parameters were determined: distances of the anterior and posterior ethmoid arteries from the skull base, and from the third lamella; changes in the angles of the lamina papyracea at the anterior and posterior ethmoid sinuses; and presence or absence of supraorbital ethmoid cell (SECs), Onodi cell, and Haller cell. The relationship between the distances which indicate the point of maximum projection by the lamina papyracea among third lamina and posterior ethmoid artery into the posterior ethmoid sinus and these anatomical factors were analyzed statistically., Results: The projection distance of lamina papyracea into the posterior ethmoid sinus was -2.6 mm to 3.4 mm, and in 41.2% of cases, projection in the direction of the nasal cavity was greater than that of the lamina papyracea at the anterior ethmoid sinus. This distance increased with increasing distance of the maximum projection point from the skull base and increasing floating distances of the anterior and posterior ethmoid arteries. The number of subjects with large projection distances was increased among those with floating posterior ethmoid arteries. In addition, subjects with SECs had significantly greater projection distances., Conclusions: Particular care should be taken to avoid injury to the lamina papyracea when opening the posterior ethmoid sinus in subjects with floating anterior or posterior ethmoid arteries, and/or SEC., Level of Evidence: 4 Laryngoscope, 131:E19-E25, 2021., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Endoscopic orbital decompression is a well-established technique for Graves orbitopathy treatment., Aims: Measurement of the ethmoid volume and its correlation with proptosis reduction in patients undergoing endoscopic orbital decompression for Graves' orbitopathy., Methods: We retrospectively reviewed clinical charts of 209 patients (319 orbits) operated by a surgeon at our institution between 1998 and 2019., Results: Average age was 46.9 years. About 83.3% of the patients were female, 54.6% were smokers, 93.8% were euthyroid at the time of decompression, 3.8% were hypothyroid and 2.4% were hyperthyroid. About 77.5% of the patients underwent bilateral surgery, the remainder and unilateral. Subsequent stages included strabismus surgery in 22.5% patients, Müllerectomy 37.8%, with or without canthoplasty (14.8 vs. 23%). Mean proptosis reduction was 4.61 mm. Mean ethmoid volume was 5.57 mm 3 . Ethmoid volume had a moderate positive correlation with proptosis reduction ( r s = 0.49, p < .001). Further investigation, statistically significant moderate correlation was found only in the small (SE) and big (BE) ethmoid groups., Conclusion: We advise evaluating ethmoid sinus pneumatization on computed tomography before decompression to estimate possible anatomical limitations. Additional wall decompression might be advocated in most severe cases.

Chondroma in the area of the spheno-ethmoidal junction is very rare. A 29-year-old male patient with chronic rhinosinusitis with nasal polyps was arranged for a preoperative computed tomography scan, and a lesion was accidentally found in his spheno-ethmoidal junction and involved the skull base. Combined with MRI, the lesion was misdiagnosed as fungal sinusitis. However, no fungal lesions were found during the operation, and cartilage tissue was confirmed only after some bone was ground away under the guidance of a surgical navigation system. Our case indicates that chondroma is easily misdiagnosed as fungal sinusitis when it appears in the sinuses and should be carefully distinguished from fungal sinusitis. Moreover, when lesions involve the skull base, surgical navigation systems are useful in accurately locating lesions.

Ethmoid sinus osteomas are rare, benign, encapsulated neoplasms of the paranasal region. They can lead to various complications such as sinusitis, orbital cellulitis, proptosis, and diplopia. The treatment protocol of these lesions changed remarkably as powered instrumentation of functional endoscopic sinus surgery evolved and otolaryngologists gained experience. Here, the authors report a 30-year-old female who was diagnosed with a giant right-sided ethmoid sinus osteoma and discuss diagnostic and treatment modalities of these lesions in consonance with the current literature.

The aim is to assess the relationship of Anterior Ethmoid Artery with the Upper Attachment of the Uncinate Process and their relation with the Lateral Lamella of the Cribriform Plate in multiplanar reconstructions (i.e. coronal, axial and sagittal) of Computed Tomography. We measured the depth of the olfactory fossa, the length of the LLCP and determined the most superior attachment of the uncinate process, which designates boundaries of the frontal recess anteriorly, laterally and medially [20,22]., Methods: All CT examinations were performed using the 320-detector Aquilion ONE CT Scanner (Canon Medical Systems, Otawara, Japan). Axial, coronal,sagittal reconstructions were performed by using dedicated workstation software (Vitrea Enterprice Siute, Version 6.7; Vital Images, Minnetonka USA). The Statistica 13 software was used for the analysis, results were considered statistically significant at the level of p&lt;0,05., Results: The most frequent types of Uncinate Process according to Landsberg- Friedman criteria in group of mens are: type I-30,77%,type II-30,77%, type III-26,92%, type VI-7,69%, type V-3,85%, type IV-0% respectively. In women&apos;s group: type III-44,12%,type II-32,35%, type I-8,82%,type V-8,82%, type IV-5,88%, type VI-0%. The median LLCP length in the anterior-posterior dimension measures 13 mm i. e. Yenigun type II on the both sides. The median value of depth in the superior-inferior dimension of the LLCP in the ethmoid roof is 5 mm i.e. Keros type II on both sides. The mean distance between Anterior Ethmoid Artery and Upper Attachment of the Uncinate Process measures approximately 9,73 mm and 9,16 mm on the right and left side respectively., Conclusions: The assessment of the AEA, UAUP and configuration of the anterior skull base on CT multiplanar reconstructions contribute to optimazing the results of frontal sinus surgery.

Background: Despite the development of anterior skull base surgery, the anatomy of the nasal bone and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part of cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential value in skull base surgery., Methods: Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were carried out., Results: The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm, respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal groove, which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull base. We also described a "cribroethmoidal canal" and a "nasal bone foramen.", Conclusion: The clinical applications of this new anatomic description concern both cribriform plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in understanding pheromone recognition in humans., (© 2019 ARS-AAOA, LLC.)

Erdheim-Chester disease is a rare infiltrative histiocytic disorder with around 800 cases being reported worldwide. Patients most commonly present with skeletal pain, but the condition has been shown to affect multiple other organs. We describe a rare presentation in which the disease infiltrated the sinuses and affected an ex-RAF pilot's vision. After extensive investigation of the elusive diagnosis, repeating of a molecular test using polymerase chain reaction analysis allowed for identification of a mutation (BRAF V600) ultimately leading to the diagnosis of Erdheim-Chester disease.

Optic neuropathy consists of several etiological events. The primary etiologies of its acute form include optic neuritis, ischemic optic neuropathy, inflammatory (nondemyelinating) disorders, and trauma. Its subacute and chronic forms are most often linked to compressive, toxic, nutritional, or hereditary-genetic causes. Visual loss, dyschromatopsia, and visual field defects are the presenting symptoms. The Onodi cell (sphenoethmoidal air cell) is an anatomic variant located laterally and superior to the sphenoid sinus; it is closely related to the optic nerve. Onodi cell disorders are rare and may be unnoticed in differential diagnoses of patients with ocular and neurological manifestations. Here, we present the case of a 12-year-old boy with headache and acute loss of sight characterized by hemianopsia in the left eye and retrobulbar optic neuropathy caused by left sphenoethmoidal sinusitis with the presence of Onodi cell inflammation. The diagnosis was confirmed by multilayered paranasal computed tomography and cerebral magnetic resonance imaging. Therapeutic treatment resulted in gradual improvement: at the 2-week follow-up, the patient no longer had headaches and his visual acuity returned to normal. Inflammation of Onodi cells should be considered in children with headache and abnormal vision., Competing Interests: There is no conflict of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

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.

Objectives: To investigate the olfactory fossa depths and lateral lamella lengths of patients with different types of developmental disorders of paranasal sinuses in comparison with normal controls., Study Design: Retrospective, archival, radio-anatomical study., Methods: We included 58 patients with maxillary sinus hypoplasia, 50 patients with frontal sinus hypoplasia/aplasia, 50 patients with sphenoid sinus hypoplasia/aplasia, and 40 normal controls. Reviewing paranasal computerized tomography scans, we noted the olfactory fossa depths and lateral lamella lengths of all the groups and compared between the hypoplasia groups and the control group., Results: Compared with the normal controls, the maxillary hypoplasia group (P < 0.001), frontal hypoplasia/aplasia group (P = 0.004), and sphenoid hypoplasia/aplasia group had significantly deeper olfactory fossa (P = 0.003). The mean lateral lamella lengths in the type 1, type 2, and type 3 hypoplastic maxillary sinus groups were significantly greater compared with that in the control group (P < 0.001). Additionally, the mean lateral lamella lengths in the hypoplastic frontal sinus, aplastic frontal sinus, and hypoplastic sphenoid sinus groups were significantly greater compared with that in the control group (P < 0.001)., Conclusion: The patients with pneumatization defects of the maxillary, frontal, and sphenoid sinuses had deeper olfactory fossa and longer lateral lamella related to increased risk of skull base injury during endoscopic sinus surgery., Level of Evidence: 3 Laryngoscope, 129:2458-2463, 2019., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

A potential mechanism underlying cigarette smoke-induced airway disease is insufficient tissue repair via altered production of matrix metalloproteinases (MMPs). Osteitis is a signature feature of recalcitrant chronic rhinosinusitis (CRS) and often results in revision surgery. The present study aimed to investigate MMP expression in the nasal tissues of asthmatic patients with CRS and any association with cigarette smoking and osteitis. Thirteen smokers with CRS and asthma, 16 non-smokers with CRS and asthma, and seven non-smoker asthmatic patients without CRS were prospectively recruited. The expression of MMPs and associated immunological factors in surgically-obtained nasal tissues was evaluated via real-time PCR and western blotting. Maximal bone thickness of the anterior ethmoid (AE) partition was measured in axial sinus computed tomography (CT) sections. MMP-1 and MMP-9 expression was increased in the nasal tissues of smokers with asthma and CRS via real-time PCR and western blot. Maximal AE partition bone thickness was greater in smokers with CRS and asthma than in non-smokers with CRS and asthma. MMP-1 and MMP-9 levels were correlated with maximal AE bone thickness. Cigarette smoking was associated with the up-regulation of MMP-1 and MMP-9 in the nasal tissues of patients with airway inflammatory diseases, and with AE osteitis, and with therapeutic resistence.

Introduction: Endoscopic sinus surgery is a well-known approach for sino-nasal pathologies. Due to close proximity to the brain and orbit, the surgeon should be aware of the sino-nasal anatomy and its associated variations. Detailed preoperative assessment of the sinus computed tomography scans reduces the frequency of severe complications in patients undergoing an endoscopic sinus surgery. So, the aim of this study is to find the prevalence of dangerous ethmoid in a tertiary center in eastern Nepal., Methods: A descriptive cross-sectional study was performed in a Computed tomography scan of 50 patients with chronic sinusitis undergoing endoscopic sinus surgery from February 2018 to August 2018 in the department of Otolaryngology and Radiology of BP Koirala institute of health sciences after taking ethical approval from Institutional Review Committee of the institute. Measurements are taken in the coronal plane. The depth of the lateral lamella of the cribriform plate was defined according to the Keros classification which defines the dangerous ethmoid. and side. Data entered in MS excel. Statistical analysis was performed in SPSS version 11.5., Results: Keros type I, II, and III were noted in 17 (17%), 54 (54%) and 29 (29%) of cases respectively. The mean width of the olfactory fossa, medial orbital wall distance and distance from medial nasal concha were 3.57mm, 8.77mm & 17.78mm respectively., Conclusions: The most common type of dangerous ethmoid was keros type II., Conclusions: The most common type of dangerous ethmoid was keros type II.

Introduction: Radiologic evaluation is mandatory to assess the type of endoscopic approach concerning sinonasal pathology and reconstruction of fractured defects before any treatment modalities are instituted related to medial wall of the orbit., Objective: The goal was to provide improved understanding of the lamina papyracea variations and the relationship with the orbital morphometry., Methods: This retrospective study was performed using computed tomography scans of 200 orbits and results were compared with respect to age, sex, laterality and LP variations., Results: Lamina papyracea variations were categorized as type A, 80.5% (161/200); type B, 16% (32/200); type C, 3.5% (7/200). For medial wall the anterior and posterior lamina papyracea heights and angles were found as 17.14mm, 147.88° and 9.6mm, 152.72°, respectively. Also, the length of the lamina papyracea, the mean area of the orbital floor, medial wall, lamina papyracea and orbital entrance were 33.3mm, 7.2cm 2 , 6.89cm 2 , 4.51cm 2 and 12.46cm 2 respectively. The orbital height and width were measured as 35.9mm and 39.2mm respectively. The mean orbital cavity depth was 46.3mm from optic foramen to the orbital entrance and the orbital volume was 19.29cm 3 . We analyzed the morphometric measurements tending to increase with aging and greater in men and the relationship of them with lamina papyracea types., Conclusion: Precise knowledge of the lamina papyracea anatomy using computed tomography is essential for safer and more effective surgery and preforming the dimensions of an implant. In this way, the postoperative complications can be decreased and the best outcome can be provided., (Copyright © 2019 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.)

Objectives: The authors investigated the olfactory fossa (OF) in patients with unilateral nasal septal deviation (NSD) and presented the lateral lamella-cribriform plate angle (LLCPA)., Methods: Paranasal sinus computed tomography images of 300 adult subjects with unilateral NSD (111 males, 189 females) were evaluated retrospectively. Septal deviation angle (SDA), Keros Classification, OF depth and width, LLCPA; and orbital plate and cribriform plate (OPCP) distance were measured., Results: The OF depth values (ipsilateral, contralateral) were found as Keros III >Keros II >Keros I (Padjusted <0.0175). The OF width values (ipsilateral) were detected as Keros I >Keros II and Keros I >Keros III (Padjusted <0.0175). In patients with higher SDA values, ipsilateral OF depth values decreased (P <0.05). The LLCPA and OPCP values were higher in Keros I and lower in Keros III (P <0.05)., Conclusion: In patients with lower LLCPA and OPCP, endoscopic sinus surgery will be more dangerous for trauma to lateral lamella and intracranial penetration.

Purpose: Ethmoidal slit (ES) and cribroethmoidal foramen (CF) have been poorly studied, without any radiological description. They may ease cribriform plate's diseases. The objective was to describe the frequency, size, and computed tomography (CT) appearance of these foramina., Methods: A two-part anatomoradiological study was performed: first on dry skulls using a surgical microscope and CT, second on patients CT scans. For each, foramina were searched for, described, and measured when possible., Results: Thirteen dry macerated skulls were studied. The orbitomeatal plane was relevant for studying ES. With microscope, ES and CF were identified in, respectively, 92% and 100% of cases. Using CT, all ES and CF were visible, with a mean length and width of, respectively, 3.9 ± 1.7 mm and 0.9 ± 0.3 mm for ES and 1.6 ± 1 mm and 0.9 ± 0.3 mm for CF. CT scans from 153 patients were reviewed. ES and CF were identified in, respectively, 80% and 91% of cases, with a mean length and width of, respectively, 3.9 ± 0.8 mm and 0.8 ± 0.2 mm for ES., Conclusion: Large-sized ES was found frequently, and were clearly visible in patients CT scans. CF was markedly smaller, but seen in most patient scans. ES and CF could be areas of least resistance in the anterior part of the cribriform plate. CT might be helpful in understanding their pathological implications.

Objective: Although more than a century has passed since antrochoanal polyps (ACPs) were first defined, etiopathogenesis still remains unclear. The aim of this study was to investigate the relationship between ACPs and sinonasal cavity variations., Subjects and Methods: One hundred and forty-four patients with ACP on paranasal sinus computed tomography scans (ACP group) and 160 paranasal sinuses without ACP (control group) were included into the study. The study group was evaluated in respect of the presence of retention cyst in the contralateral maxillary sinus and sinus bone wall sclerosis thickening. Both groups were also compared with respect to the frequency of sinonasal anatomic variations, nasal septal deviation, variations of the uncinate process insertion, concha bullosa, paradoxical middle turbinate, and accessory maxillary sinus ostium. In the ACP group, the cases with septal deviation (SD) were also evaluated whether the deviation convexity was towards the polyp side or the opposite side. In addition, the posterior extension of ACPs were evaluated in three groups as middle meatus, nasopharynx, and oropharynx extension., Results: The prevalence of retention cyst, sinus wall sclerosis thickening, SD, and accessory maxillary ostium was significantly higher in the ACP group. A negative directional correlation was determined between the SD side and ACP side. When the ACP extensions were examined, middle meatus extension was seen in 32.6%, nasopharynx in 56.3%, and oropharynx in 11.1%., Conclusion: Accessory ostium may be an accelerating factor in the transformation of retention cyst to ACP. Furthermore, the changes in the nasal passage airflow on the opposite side suggest that SD contributes to this process., Competing Interests: None

Purpose: The variations of the anterior ethmoidal artery (AEA) in different populations should be recognized by surgeons to prevent unwarranted complications during surgery. The aim of this study was to assess the anatomical variations of AEA in Asian population., Methods: A cross-sectional study of 252 AEA identified by computed tomography (CT) of the paranasal sinuses. The multiplanar CT images were acquired from SOMATOM ® Definition AS+ and reconstructed to axial, coronal and sagittal view at 1 mm slice thickness., Results: 42.5% of AEA was within skull base (grade I), 20.2% at skull base (grade II) and 37.3% coursed freely below skull base (grade III). The prevalence of supraorbital ethmoid cell (SOEC) and suprabullar cell (SBC) was 29.8% and 48.0%. The position of AEA at skull base has significant association with SOEC (p < 0.001), but not with SBC (p = 0.268). Type I Keros was 42.1% and Type 11 Keros was 57.9%. When lateral lamella's height is longer, the probability increases for AEA to course freely within the ethmoid sinus (p = 0.016). The mean distance of AEA from skull base was 1.93 ± 2.03 mm, orbital floor 21.91 ± 2.47 mm and nasal floor 49.01 ± 3.53 mm., Conclusions: The position of AEA at skull base depends on the presence of SOEC and length of lateral lamella, but not with SBC. When compared to European population, the mean distance between AEA and nasal floor is shorter in Asians.

Objectives: We investigated the relationship between Onodi cells and optic canal by paranasal sinus computed tomography (PNSCT)., Methods: In this retrospective study, 508 PNSCT (265 males and 243 females) was examined. Onodi cell presence, pneumatization types, optic canal types; and also sphenoid sinusitis and anterior clinoid process pneumatization were evaluated., Results: The prevalence of Onodi cells was 21.2% of the patients. Onodi cells were observed 40.7% on the right side and 25.9% on the left side. In 33.4% of the patients, bilateral Onodi cells were present. Male/Female ratio was 24.5%/17.6%. Onodi cell types were detected as Type I > Type II > Type III bilaterally. There was a positive correlation between the right and left Onodi cell types (p < 0.05). Optic canal types were detected as Type IV > Type I > Type II > Type III. bilaterally. There was a positive correlation between right and left optic canal types. Onodi cell presence and ACP pneumatization were found as statistically significant (p < 0.05). In 65.5% of the patients, Onodi cells and ACP pneumatization were absent. ACP pneumatization was present in 35.4% of the cases. In nine cases, bilateral Onodi cells and ACP pneumatization were detected. Sphenoid sinusitis was detected in 11.4% of Type I and 13.8% of the Type II Onodi cells on the right side. On the left side, it was detected in 12.9% of the Type I and 19.0% of Type II Onodi cells., Conclusion: Identification of Onodi cell is very important clinically because of its proximity to optic nerve canal. We concluded that type IV Onodi-optic canal relationship was the most common finding in our study. Onodi cell presence and their patterns of pneumatization must be evaluated on PNSCT preoperatively to avoid optic canal damage.

Background: With an aging population, it is important to understand age-related anatomic changes in the nasal cavity and cribriform plate (CP) that may have clinical implications., Methodology: Computed tomography (CT) scans obtained for non-rhinologic conditions were divided into a young cohort (N=35, 18-34 years old) and an older adult cohort (N=32, 80-99 years old). Intranasal airspace volumes and bony anatomy of the CP were manually segmented using OsiriX software. The CP was assessed for mean Hounsfield Units (HU) and percentage of olfactory foramina. Deformation based morphometry (DBM) was then performed on the same cohort and correlated with manual measurements., Results: Individual nasal cavity volumes increased 17-75% with age. Regression analysis of all scans revealed age to be the predominant variable influencing intranasal volume differences when controlling for sex and head size. Mean HU of the CP negatively correlated with age. No age-related differences in bone stenosis of olfactory foramina were identified. Automated DBM measurements of intranasal volumes, as well as CP and zygoma mean HU correlated with manual measurements., Conclusion: Older subjects have a global increase in intranasal volumes and diffuse bone density loss in the CP. The clinical impact of age-related anatomic changes in the nasal cavity and CP requires further investigation.

In recent years, the perpendicular plate of the ethmoid (PPE) has emerged as a new autogenous grafting material in rhinoplasty and septoplasty of nasal deviation. However, no studies have outlined the precise size, shape, and morphologic features of the PPE. Therefore, this study aimed to provide detailed information on the anatomical and morphologic characteristics of the PPE to assist surgeons in performing surgeries that are more precise. About 104 Chinese patients who underwent paranasal computed tomography were assessed in this study. By analyzing the features of the PPE reconstructed with 3-dimensional models, the characteristics of the PPE at different stages of development and according to sex were observed. The PPE had a flat shape, and its lower part was relatively thin. It usually developed horizontally with age, which contributed to expansion of the PPE area. The dimensions of the PPE were significantly larger in male patients than in female patients. Through the reconstruction and measurement of Chinese patients' PPE, the authors have established precise information about the PPE's anatomical and morphologic features. The flat shape and proper size, which are similar to those of nasal septum cartilage, make the PPE an ideal alternative to conventional autogenous grafting materials. The findings might be useful to surgeons in helping them perform surgeries that are more precise.

The anterior cranial fossa is an important anatomical landmark in clinical orthodontics consisting of the frontal, ethmoid, and sphenoid bones. The relationships between these bones remain poorly understood. The purposes of the present study were to describe the morphological relationships among the three bones and to discuss the factors contributing to individual variations in adult skulls based on postnatal development. Skulls of 100 Indian adults and 18 Japanese juveniles were observed both macroscopically and using computed tomography images in the median sagittal plane. Three types of relationship were seen among the three bones in adult skulls: (a) a triangular border between ethmoid and sphenoid bones (ethmoid spine), (b) a straight or concave border between ethmoid and sphenoid bones, and (c) frontal bone lying between the ethmoid and sphenoid bones. In the juvenile skull, structures corresponding to those in adults were observed. These three bones comprise the anterior cranial base, each with differing developmental processes, and slight differences in these processes seem to be reflected in the morphological variations seen among adults., Competing Interests: None declared.

Introduction: The aim of this study was to report the first case of diagnosis of a rare ethmoid sinolith by cone-beam computed tomography (CBCT) and discuss the importance of carefully assessing the entire volume of the images regardless of the region of interest., Case Presentation: A 22-year-old woman underwent CBCT examination to assess the upper permanent canine teeth. Analysis of the entire volume of CBCT revealed an oval-shaped hyperdense, homogeneous, expansive formation with defined boundaries located in the ethmoid bone. The differential diagnosis of a sinolith in the ethmoid sinus was confirmed after removal of the lesion by nasoendoscopy and histopathological examination., Conclusion: The diagnosis of lesions in the ethmoid sinus is challenging because of the complex anatomy of this region. Considering the limitations of two-dimensional X-ray examination, CBCT examination has become an important imaging modality for the diagnosis of these calcifications. In addition, the ability of the dental surgeon to assess the entire volume of the CBCT images and the knowledge of imaging features of these calcifications allows for recognition of incidental findings, facilitating early diagnosis and appropriate treatment.

Background: Several authors highlighted the limitations of the Keros classification system in predicting intracranial entry risk. Recently, our group proposed a new classification system based on the angle formed between the lateral lamella of the cribriform plate (LLCP) and the continuation of an horizontal plane passing through the cribriform plate (Gera classification). The aim of this study was to analyze whether the risk of iatrogenic cerebrospinal fluid leak (CSF-L) was better predicted by Keros or Gera classification., Methodology: The pre-operative CT scans of 24 patients (CSF-L group) who suffered from iatrogenic CSF-L during endoscopic sinus surgery (ESS) were compared to those obtained from a group of 100 patients who underwent uneventful ESS (control group). The skull base measurements as well as the distribution of Keros and Gera classes in the 2 groups were analyzed., Results: No difference in the distribution of Keros classes or in the depth of the cribriform plate between CSF-L and control group were demonstrated. On the contrary, significant differences in the distribution of Gera classes and in the degree of the angle formed by the LLCP and the continuation of the horizontal plane passing through the cribriform plate were found. In particular, according to Gera classification system, 19 out of 24 patients in the CSF-L group were considered at risk for iatrogenic CSF-L., Conclusions: Gera classification system might be more sensitive to anatomical variations associated with CSF-L than the Keros one, further suggesting the application of the former during the preoperative CT scan evaluation.