Relation between anterior ethmoidal artery course on computed tomography and supraorbital ethmoid cell and Keros classification.

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.

A Safe Technique for Excising the Perpendicular Plate of the Ethmoid Bone in Patients with Crooked Nose: A Finite Element Analysis.

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 .

Examination of ethmoidal roof regarding Keros and Yenigun classifications in a Turkish population: a computerized tomography study.

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.

Radiological relationship of the ethmoid slit with the frontal sinus and the anterior ethmoidal artery and applications to the frontal sinus drillout.

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.

Anterior ethmoid and frontal sinus drainage pathways: five patterns formed and defined by their bony walls.

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.

Evaluation of Cribriform Plate Dimensions and Middle Turbinate Length in Patients With Vomeral Agenesis: A Computed Tomography Study.

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.

Anatomical Variations of Anterior Ethmoidal Foramen and Cribriform Plate: Relations With Sex.

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.

Anatomical Study of Ethmoidal Foramina and Optic Canal in Endoscopic Trans-Nasal Approach to Anterior Skull Base.

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 ±â€Š0.26, 7.29 ±â€Š0.25, and 7.76 ±â€Š0.41 mm, respectively. Angle between line from nostril to ethmoidal foramina and horizontal plane are 47.50°â€Š±â€Š1.03°, 41.67°â€Š±â€Š1.33°, 37.20°â€Š±â€Š1.34°, 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.

Ethmoid roof morphometric measurements of a pediatric population using computed tomography.

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.

The relationship between ethmoidal foramina and orbital fat herniation.

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.

Ambiguous "olfactory" terms for anatomic spaces adjacent to the cribriform plate: A publication database analysis and quest for uniformity.

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.

[Applied anatomy of the medial orbital wall]. / Prikladnaya anatomiya medial'noi stenki glaznitsy.

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.

Chondroma in the Area of the Spheno-Ethmoid Junction.

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.

Giant Ethmoid Sinus Osteoma Protruding into the Maxillary Sinus.

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.

Optic Neuropathy, Secondary to Ethmoiditis, and Onodi Cell Inflammation during Childhood: A Case Report and Review of the Literature.

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.

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.

Is there a relationship between Onodi cell and optic canal?

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.

Radiologic changes in the aging nasal cavity.

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.

Anatomical Characteristics of the Perpendicular Plate of the Ethmoid: An Analysis of Paranasal Sinus Computed Tomography via Three-Dimensional Reconstruction.

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.

Olfactory Fossa and New Angle Measurements: Lateral Lamella-Cribriform Plate Angle.

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.