Computed tomographic and endoscopic analysis of supraorbital ethmoid cells

Personal identification using frontal sinus coding methods: The effect of mixed image modality comparisons

Several code-based methods have been created for comparing the frontal sinus in skeletal identification scenarios. However, little is known regarding matched-pair accuracy rates of these methods or how varying image modalities may affect these rates. The goals of this study were to validate the exclusion rates and to establish matched-pair accuracy rates of two well-cited coding methods, Cameriere et al. [23] and Tatlisumak et al. [24]. Additionally, individual variables were assessed for consistency in scoring between image modalities. Using a sample of U.S. African American, Native American, and European American females and males (n = 225), we examined individual variable scoring and string codes between two different image modalities (radiographs and CT-based 3D models). Arcades showed poor scoring consistency between modalities (p < 0.001). Although exclusion rates were similar to those reported in the original studies (93%-96%), matched-pair accuracy rates were low (13%-18%). None of the demographics (collection, sex, age, ancestry, and orientation) had an effect on the odds of a match. Interobserver and intraobserver analyses showed moderate to near-perfect agreement for all variables except supraorbital cells, which had minimal to no agreement. Currently, we do not recommend the application of these frontal sinus coding methods independent of other supporting identification methods given low variable consistency and accuracy rates. Visual identification should still be used to include or exclude an identification when using the frontal sinus.

Clinical and imaging features of ethmomaxillary sinus compared to Haller's cell

PURPOSE

Understanding the anatomy of the paranasal sinuses and their variations is essential to achieving safe and effective endoscopic sinus surgery. The ethmomaxillary sinus (EMS) is a relatively under-researched anatomical variation. This study investigated the prevalence, clinical features, and effect of EMS on the maxillary sinus in comparison with Haller's cells.

METHODS

Patients who visited the Rhinology Clinic at our hospital for rhinologic symptoms between January 2020 and December 2020. Computed tomography (CT) scans of paranasal sinuses were obtained at 1 mm-section thickness. Using CT scans, we investigated the clinical features of EMS, measured maxillary sinus volume, and analyzed the presence of maxillary sinusitis.

RESULTS

EMS was observed in 26 of the 250 patients (10.4%). The male-to-female ratio was equal. The age ranged from 18 to 83 years (mean age, 56.3). Of the patients with EMS, 65.4% were unilateral and 34.6% were bilateral. The prevalence of Haller's cells was similar to that in EMS (10.8%). In the analysis of patients with unilateral EMS, the EMS side was found to have a significantly reduced maxillary sinus volume compared to the opposite side, whereas the difference was not significant in Haller's cells. There was no significant relationship between EMS or Haller's cells and maxillary sinusitis.

CONCLUSIONS

EMS can significantly affect maxillary sinus volume. Therefore, surgeons should thoroughly review PNS CT scans before paranasal sinus surgery to determine the presence and features of EMS.

International Frontal Sinus Anatomy Classification (IFAC): evaluation of frontoethmoidal cells prevalence in a Brazilian population

OBJECTIVES

The aim of this study was to evaluate the prevalence of the frontal cell variants according to International Frontal Sinus Anatomy Classification (IFAC), in the population of a Brazilian tertiary hospital, and analyze the reliability of the classification between observers.

METHODS

A cross-sectional study in the Hospital de Clínicas of the State University of Campinas, Brazil. One hundred and three Computed Tomography's (CTs) were evaluated by radiologists and otorhinolaryngologist to estimate the prevalence of frontoethmoidal cells according to the IFAC. Intraclass Correlation Coefficient (ICC) among examinators was used to evaluate reliability of this findings.

RESULTS

103 CT scans, totaling 206 sides, were evaluated independently. The agger nasi cell was the most prevalent, present in 95.63% of cases, 37.86% of the exams contained supra agger cells, frontal supra agger cell showed prevalence 37.37%; suprabular cell was present in 77.18% of the sides. As for the frontal suprabular cell, the prevalence was 30.09%, the supraorbital ethmoid cell was present in 32.03%, and frontal septal cell had a 33.49% prevalence. The ICC among the evaluators was classified as "good reliability" or "excellent reliability" for all cells.

CONCLUSION

This study describes the frontal cell prevalence among a population in tertiary Brazilian hospital, using the IFAC. This classification had a high ICC.

LEVEL OF EVIDENCE

Level 2: Individual cross-sectional study with consistently applied reference standard and blinding.

Supraorbital ethmoid cells (SOECs), anterior ethmoid artery notch and ethmoid roof relation in PNSCT

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).

Radiological anatomical variations of the lateral nasal wall and anterior skull base amongst different populations: A systematic review and meta-analysis

OBJECTIVES

To determine the anatomical variations of the lateral nasal wall and anterior skull base amongst populations in different geographical regions.

DESIGN

Systematic review and meta-analysis.

METHODS

Using PRISMA guidelines, SCOPUS and PUBMED databases were searched from inception until 1 March 2022. The regions and populations identified were from Europe, Asia, Middle East, Australia-New Zealand-Oceania, South America, North America and Africa. Random-effects model was used to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I² statistic and Cochran's Q test.

MAIN OUTCOME MEASURES

Anatomical variations of the lateral nasal wall and anterior skull base confirmed by computed tomography scan.

RESULTS

Fifty-six articles were included with a total of 11 805 persons. The most common anatomical variation of the ostiomeatal complex was pneumatization of the agger nasi (84.1%), olfactory fossa was Keros type 2 (53.8%) and ethmoids was asymmetry of the roof (42.8%). Sphenoethmoidal and suprabullar cells have a higher prevalence in North Americans (53.7%, 95% CI: 46.00-61.33) while asymmetry of ethmoid roof more common in Middle Easterns (85.5%, 95% CI: .00-100). Bent uncinate process has greater prevalence in Asians while supraorbital ethmoid cells and Keros type 3 more common in non-Asians. The overall studies have substantial heterogeneity and publication bias.

CONCLUSION

Certain anatomic variants are more common in a specific population. The 'approach of analysis' plays a role in the prevalence estimates and consensus should be made in future studies regarding the most appropriate 'approach of analysis' either by persons or by sides.

The important adjacent structures for anterior ethmoidal artery in FESS: Anterior ethmoidal artery canal angle, supraorbital ethmoid cells and Keros classification

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.

Computed Tomography Analysis of the Anterosuperior Portion of the Bulla Lamella in Chinese Subjects and Its Surgical Significance in Endoscopic Frontal Sinusotomy

INTRODUCTION

The anterosuperior portion of the bulla lamella can extend into the frontal sinus and form the supra bulla frontal cell (SBFC) and supraorbital ethmoid cell (SOEC). This can affect the frontal drainage pathway and make surgery more challenging.

OBJECTIVES

The aim of the study was to compare the anatomical characteristics of SBFC and SOEC in Chinese chronic rhinosinusitis (CRS) patients and explore the relationship between the cells and frontal sinusitis (FS). The surgical skills in dealing with these cells were also studied.

METHODS

We prospectively identified SBFC and SOEC in 114 patients with CRS by computed tomography (CT). The sides of the patients were divided into groups A (with FS) and B (without FS). CT scans were analyzed to distinguish the SBFC, SOEC, and the drainage pathway. Statistical analysis was conducted to determine whether the cells were associated with the occurrence of FS.

RESULTS

The prevalence of frontal cells was as follows: SBFC: 9.65%, SOEC: 21.93%. There was an association between the presence of SBFC and FS (p < 0.05). The anterior drainage pathway was present in patients with SBFC and SOEC, anterolateral pathway in those with SBFC/SOEC coexisting with the frontal septal cell, and anteromedial pathway in those with SBFC/SOEC coexisting with the supra agger frontal cell.

CONCLUSIONS

There was an association between the presence of SBFC and the occurrence of FS. Extension of the anterosuperior portion of the bulla lamella into the frontal sinus obstructed the drainage pathway posteriorly. Understanding the anatomy may help surgeons thoroughly dissect the bulla lamella.

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

PURPOSE

The aim of this study was to investigate the pneumatization degree of ethmomaxillary sinus (EMS) and adjacent structures, and its impact on chronic rhinosinusitis (CRS).

METHODS

A retrospective analysis of paranasal sinus CT scans of 996 patients was conducted. The maximum vertical diameter of EMS in the coronal plane was measured, allowing EMS to be classified, and its impact on ipsilateral CRS were examined.

RESULTS

The prevalence of EMS was 11.9%. The maximum vertical diameter of EMS in the coronal plane ranged from 3.68 to 28.76 mm with a mean (± SD) of 11.32 ± 5.12 mm. The prevalence rates of EMS in CRS sides and non-CRS sides were 12.5% and 9.3%, respectively, which was significantly different (χ² = 4.495; p < 0.05). The difference in prevalence between the three types of EMS in ipsilateral CRS was statistically significant (χ² = 6.733; p < 0.05). The difference in Lund-Mackay (LM) score of ipsilateral CRS between the three types showed no statistically significant difference (H = 4.033; p > 0.05).

CONCLUSION

EMS is a common anatomical variation with marked individual differences in shape and pneumatization degree. A higher degree of EMS pneumatization may contribute to the occurrence of CRS; this should be investigated before surgery.

Variability of the Anterior Ethmoid Artery in Endoscopic Sinus Surgery

INTRODUCTION

The anterior ethmoidal artery (AEA) demonstrates anatomic variability relative to its descent from the anterior skull base. Our study's objective was to assess for correlation of AEA descent and laterality, in addition to correlation of AEA descent and the presence of supraorbital ethmoid cells (SOEC) and concha bullosae (CB).

METHOD

A retrospective study was performed at a tertiary rhinology center from January 2019 to January 2020. Noncontrast maxillofacial computed tomography scans were examined independently by 2 fellowship trained rhinologists. The vertical distance from both left and right AEAs to the ipsilateral skull base were compared and correlated with the presence of ipsilateral SOEC and CB.

RESULTS

Computed tomography scans from 50 subjects were included. Mean age was 50.68 years (40% females). The distance of AEA to the skull base was greater on the left when compared to the right (62% vs 48%) (P < .05). The left AEA had an average descent of 2.84 mm versus 1.78 mm on the right (P < .05). An SOEC was present in 56% of cases. Thirty-eight percent of subjects had both SOEC and AEA descent on the right, while 52% of subjects had both on the left. This reached a statistical significance on both sides (P < .05). Concha bullosa was present in 35% of cases, with both AEA descent and CB present in 16% on the right, and 32% on the left.

CONCLUSION

The AEA displays variability in vertical descent from the skull base, with greater variability on the left. These findings implore vigilance with evaluation of preoperative imaging and during sinus surgery, especially in the presence of SOEC and CB.

Computed Tomography Image Analysis and Clinical Correlations of Retromaxillary Cells

OBJECTIVE

This study aimed to investigate and analyze the anatomic characteristics of the retromaxillary cell (RMC) by using computed tomography (CT) images of paranasal sinuses and to improve its identification with ethmomaxillary sinus (EMS).

METHODS

The paranasal sinus CT scans of 441 outpatients or inpatients in our hospital from January 2018 to October 2018 were analyzed. The incidence of RMC, EMS, Haller cell, imaging anatomical characteristics, and morphological manifestations were observed via sinus CTs. The relationship of RMC and ipsilateral maxillary sinusitis was analyzed.

RESULTS

The incidence of RMC is 83.90% (740/882). The incidence of males and females was 83.81% (414/494) and 84.02% (326/388), respectively. The incidence of bilateral (72.79%, 321/441) was much higher than that of unilateral (22.22%, 98/441). The lateral extension of the RMC ranged from 1.18 to 13.31 mm, with an average of 6.10 ± 2.03 mm. The incidence of ipsilateral maxillary sinus opacification on the RMC sides and non-RMC sides has no significance difference (χ² = .054, P = .459). The incidence of Haller cell and EMS decreased significantly in the presence of RMC (P < .01).

CONCLUSION

The RMC is an anatomical variation originating from posterior ethmoid cells, which is commonly encountered in the clinic. The pneumatization of RMC is highly variable, and a bilateral is common. During endoscopic sinus surgery, it is necessary to carefully identify such an air cell to ensure the complete opening of the paranasal sinus during surgery.

Analysis of anatomical variation of the inclination of lamellas attached to the skull base and its correlation with the anterior ethmoidal artery floating in the ethmoid sinus for use in endoscopic sinus surgery

PURPOSE

Attention to the inclination of lamellas attached to the skull base, including the basal lamella of the middle turbinate, facilitates the intraoperative identification of each lamella without requiring the use of a navigation system. We classified the inclination between the lamella and the skull base in preoperative computed tomography (CT) images and examined the relationship between the lamellas attached to the skull base, including the basal lamella of the middle turbinate, and the position of the anterior ethmoidal artery (AEA). We aimed to develop a preoperative classification to help prevent intraoperative injury of the AEA.

METHODS

We retrospectively investigated the paranasal sinus sagittal section CT slices of 366 sides of 183 patients to assess the inclination of lamellas attached to the skull base and the AEA location. We also reviewed the AEA position, its correlation with the supraorbital ethmoid cell, and the lateral lamella of the cribriform plate.

RESULTS

We classified the lamella inclination at the skull base as the anterior direction, perpendicular direction, and posterior direction types. Lamellas containing a floating AEA inclined in the anterior direction toward the skull base were observed in 68.9% of sides, inclination in the perpendicular direction was noted in 30.5% of sides, and inclination in the posterior direction was noted in 0.5% of sides.

CONCLUSION

It is easier to identify the AEA intraoperatively when the lamella inclination of the skull base attachment is recognized based on preoperative CT findings. This approach could be applied to all paranasal sinus lamellas and assist in identifying the AEA and other nearby structures.

Ethnic Variation of Sinonasal Anatomy on CT Scan and Volumetric Analysis

To determine Ethnic differences in the frequency of the relatively common anatomical variants along with difference in anatomy of sinonasal region with surgical importance. A study was conducted to determine the frequency of anatomical variants, volumes of paranasal sinuses using computed tomography and to identify any difference between Group A consisting of people of Indian subcontinent and Group B consisting of people from north east Asian region. Volumetric analysis done using cumulative of area multiplied by slice thickness. The results were compared using Chi square test, p value < 0.05 was considered statistically significant. Among the common and uncommon anatomical variants (Agger nasi, pneumatized uncinate, concha bullosa etc.) there was no significant difference between the two groups. In both the groups Keros Type 1 was the most common type of ethmoid roof seen. On volumetric analysis sphenoid sinus volume was found to be higher in Indians without mongoloid features. Hence it's ideal that in this era of endoscopic sinus surgery we tailor make approaches to address individual anatomical variation.

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.

Reliability of the supraorbital ethmoid cell vs Keros classification in predicting the course of the anterior ethmoid artery

BACKGROUND

We previously showed that the supraorbital ethmoid cell (SOEC) is a reliable landmark for identifying the anterior ethmoid artery (AEA). Recent data have suggested that Keros classification is also a dependable predictor. We aim to characterize the location of the AEA and its relation to the skull base in patients with and without SOEC using the Keros classification.

METHODS

Retrospective radiographic evaluation of computed tomography (CT) scans of 76 patients (40 with SOEC, 36 without) was conducted. Distance of AEA from skull base and prevalence of AEA outside of the skull base were measured on each side and compared between groups using the 2-sample t test and χ² test, respectively. Subgroup analysis was carried out based on the Keros classification.

RESULTS

Mean distance of AEA from the skull base was 1.32 ± 1.5 mm in patients with SOEC and 0.47 ± 1.08 mm in those without (p < 0.001). Prevalence of AEA outside of the skull base was 53.8% in those with SOEC and 18.1% in those without (p < 0.001). Comparing patients with SOEC to those without, AEA was found below the skull base in 30% vs 0% of cases with Keros type 1 (p = 0.45), 58% vs 14.5% with Keros type 2 (p < 0.001), and 60% vs 50% with Keros type 3 (p = 0.72).

CONCLUSION

The presence of SOEC is associated with a higher prevalence of the AEA coursing below the level of the skull base in all Keros types, thus placing the artery at greater risk for injury. Careful surgical planning is needed to avoid potential orbital complications.

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

PURPOSE

Anterior ethmoidal artery (AEA) is at risk of injury in endoscopic sinus surgery due to its location. The aim of this review was to assess the anatomical variations of AEA and their significance.

METHODS

A literature search was performed on PUBMED, SCOPUS AND EMBASE. The following keywords were used: ethmoidal artery; anterior ethmoidal artery; anterior ethmoidal canal; ethmoid sinus; ethmoid roof; skull base. The search was conducted over a period of 6 months between October 2016 and April 2017.

RESULTS

105 articles were retrieved. 76 articles which were either case reports or unrelated topics were excluded. Out of the 29 full text articles retrieved, 16 articles were selected; 3 were cadaveric dissection, 5 combined cadaveric dissection and computed tomography (CT) and the rest were of CT studies. All studies were of level III evidence and a total of 1985 arteries were studied. Its position at the skull base was influenced by the presence of supraorbital ethmoid cell (SOEC) and length of the lateral lamella of cribriform plate (LLCP). Inter population morphological variations contribute to the anatomical variations.

CONCLUSIONS

The average diameter of AEA was 0.80 mm and the intranasal length was 5.82 mm. 79.2% was found between the second and third lamellae, 12.0% in the third lamella, 6% posterior to third lamella and 1.2% in the second lamella. Extra precaution should be taken in the presence of a well-pneumatized SOEC and a long LLCP as AEA tends to run freely below skull base.

International Frontal Sinus Anatomy Classification and anatomic predictors of low-lying anterior ethmoidal arteries

BACKGROUND

The International Frontal Sinus Anatomy Classification (IFAC) was introduced to more accurately characterize ethmoid and frontal sinus pneumatization patterns. The prevalence of IFAC cells and their anatomic associations have not been described.

OBJECTIVE

The goal was to examine the prevalence of IFAC cells and determine radiologic features associated with a low-lying anterior ethmoidal artery (LAEA).

METHODS

Imaging of adult patients who underwent computed tomographies from January 2015 to March 2016 were retrospectively reviewed by using the IFAC classification. We also measured the distance from the skull base to the anterior ethmoidal artery (AEA), the height of the lateral lamella of the cribriform plate, and anterior-posterior diameter from the anterior wall of the frontal sinus to the skull base (APF). Patients with a history of sinus surgery, trauma, malignancy, or congenital anomaly were excluded. Statistical analysis was performed by using Pearson correlation coefficients and χ2 tests.

RESULTS

A total of 95 patients met the inclusion criteria. There was a significant association between supraorbital ethmoid cells and an LAEA (p < 0.001), with a significant effect size (φ = 0.276, p = 0.007). An inverse relationship was observed between Keros type I classification I and an LAEA (p < 0.001), with a significant effect size (φ = -0.414, p = 0.000). Significant associations were found between the AEA distance from the skull base and the cribriform lateral lamella height (R = 0.576, p < 0.001). In addition, there was a significant association between the AEA distance from the skull base and the APF (R = 0.497, p < 0.001).

CONCLUSION

The presence of a supraorbital ethmoid cell and a wide APF were associated with an LAEA. There was a significant relationship between Keros type I classification and the AEA adjacent to the skull base. Delineation of these anatomic relationships may be helpful during endoscopic sinus surgery to avoid complications.

Imaging and anatomical features of ethmomaxillary sinus and its differentiation from surrounding air cells

OBJECTIVE

The aim of this study was to investigate the imaging anatomical characteristics and clinical significance of the ethmomaxillary sinus (EMS).

METHODS

The study included a total of 280 ENT Outpatient Department patients with nasal symptoms whose paranasal sinus CT scans were analyzed from January 2012 to December 2016. The anatomical imaging characteristics of EMS were observed.

RESULTS

EMS was observed in 23 of 280 patients, with an incidence of 8.2%. Bilateral EMS appearance in 17 cases (73.9%) was significantly higher than that of unilateral EMS in 6 cases (26.1%) (P < 0.01). EMS occurs when there are anterior or anterior-inferior cells of the posterior ethmoidal sinus (PEs) extending toward the maxillary sinus (MS) and entering the MS through the maxillary hiatus rather than spreading from outside of the MS. EMS is surrounded by five walls, and the main position of EMS was invariably located in the posterior-superior corner of the MS and draining to the superior nasal meatus (SNM). EMS must be differentiated from SNM, sphenoid sinus, and retromaxillary pneumatization of PEs, because they may appear between the MS and the orbital floor.

CONCLUSION

EMS was not a rare variation that should be careful identification during endoscopic sinus surgery. Accurately confirming EMS is the key to completely opening and removing lesions in the MS and EMS.

Computed tomographic analysis of frontal recess cells in pediatric patients

OBJECTIVE

To describe the prevalence of frontoethmoid cells and superior uncinate process attachment in pediatric patients with sinonasal symptoms.

METHOD

Fifty high-resolution computed tomographies of the paranasal sinuses for pediatric patients were evaluated for the presence of frontoethmoid cells and uncinate process insertion. The computed tomographies were randomly collected for patients with sinonasal symptoms (age range, 4-15 years) at our clinic. The prevalence of these cells was compared against age group and type of uncinate process.

RESULTS

The prevalence of each structure was agger nasi cell (97%), type 1 frontal cell (39%), type 2 frontal cell (27%), type 3 frontal cell (11%), type 4 frontal cell (1%), supraorbital ethmoid cell (38%), suprabullar cell (57%), frontal bullar cell (9%), and interfrontal septal cell (16%). When excluding the agger nasi cell, 48 patients (96%) had at least one type of frontoethmoid cell and 43 (86%) had at least one frontal cell. The frequency of these cells did not significantly differ based on sex or uncinate process insertion, but it did with age. Lamina papyracea was the most common site of superior uncinate process attachment.

CONCLUSION

Our results indicated a high frequency of frontoethmoid cells in the pediatric age group. The prevalence of these variations changes during childhood development. As in adults, lamina papyracea is the most common site of superior uncinate process attachment. Recognition of these variations in the frontal recess can provide useful information for safe and efficient endoscopic dissection in the frontal recess region.

Frontal recess anatomy in Japanese subjects and its effect on the development of frontal sinusitis: computed tomography analysis

Background

Comprehensive understanding of frontal recess anatomy is essential for the successful treatment of patients with frontal sinus disease. This study was designed to determine the prevalence of specific frontal recess cells in Japanese subjects and the association of these cells with the development of frontal sinusitis.

Methods

Frontal recess anatomy was analyzed using high-resolution spiral computed tomography images of paranasal sinuses from December 2008 through September 2011. The distribution of various frontal recess cells in patients with and without frontal sinusitis was compared by logistic regression analysis.

Results

A total of 150 patients met the criteria, and 300 sides were analyzed. Agger nasi cells were present in 88.0 % of sides; frontal cell types 1 (FC1), 2 (FC2), 3 (FC3), and 4 (FC4) were present in 37.0 %, 6.3 %, 4.3 %, and 1.3 %, respectively; supraorbital ethmoid cells in 6.0 %, suprabullar cells in 37.0 %, frontal bullar cells (FBC) in 7.0 %, and interfrontal sinus septal cells in 8.6 %. Multiple logistic regression analysis showed that the presence of FBCs was significantly associated with the development of frontal sinusitis (p = 0.043).

Conclusions

The frequencies of frontal recess cells in Japanese adult patients were similar to those reported for other East Asian adult populations, including Chinese, Korean, and Taiwanese. Anatomically, FBCs may show a greater association with the development of frontal sinusitis than other frontal recess cells.

Frontal sinus surgery anterior to the ethmoid bulla

The frontal sinus surgery is difficult to perform but the ethmoid bulla is a relative, constant landmark in the middle turbinate that can improve the surgery. The purpose of this study was to evaluate the validity, security, and predominance of approaches to the frontal sinus via the route anterior to the ethmoid bulla. The data from 370 endoscopic frontal sinus surgery cases from our center were integrated and retrospectively analyzed. Three hundred twenty-nine patients underwent frontal sinus surgery via the route anterior to the ethmoid bulla. An additional 27 patients underwent frontal sinus surgery with mini-trephination, 13 patients with the Draf II procedure, and 1 patient had applied MELP (modified endoscopic Lothrop procedure). No serious complications occurred; however, there were 3 cases of eyelid ecchymosis and 1 case of anterior ethmoid artery bleeding. In all, 319 patients (86.2%) were cured, an improvement was noted in 36 of the patients (9.7%), and there was no improvement in 15 patients (4.1%). Frontal sinus surgery via the route anterior to the ethmoid bulla is valid, relatively safe, and can be applied in most cases involving frontal disease.

Supraorbital ethmoid cell: a consistent landmark for endoscopic identification of the anterior ethmoidal artery

OBJECTIVE

To demonstrate that the supraorbital ethmoid cell (SOEC) is a consistent and reliable landmark in identification of the anterior ethmoidal artery (AEA).

STUDY DESIGN

Retrospective radiographic study.

SETTING

Tertiary care rhinology practice.

SUBJECTS AND METHODS

The computed tomography (CT) scans for 78 consecutive patients were evaluated for the presence of SOECs, degree of pneumatization, and location of the AEA in relation to fixed anatomic structures. Forty-one patients with normal SOECs were identified and compared with a group of 15 patients with pathological expansion of the SOEC secondary to inflammatory disease. The CT findings were correlated with endoscopic findings.

RESULTS

The incidence of SOECs was 53%. Compared to normal SOECs, expanded SOECs had significantly greater pneumatization laterally (9.3 vs 18.5 mm, respectively; P < .0001) and AEAs that were significantly farther from the skull base (1.3 vs 6.6 mm, respectively; P < .0001). The distance between the AEA and the nasal beak was similar between the 2 groups (P = .1). More importantly, 68 of 68 sides with normal SOECs (100%) demonstrated the AEA within or in continuity with the posterior border of the SOEC opening. In patients with pathological expansion, the AEA remained within the posterior border of the SOEC opening in 19 of 19 sides (100%), despite significant expansion of the cell superolaterally.

CONCLUSION

This is the first study to demonstrate a consistent landmark to identify the AEA even in cases of distorted anatomy of the frontal recess. Identifying the SOEC is a practical and reliable technique for minimizing the risk of injury to the AEA during frontal recess surgery.

Frontal sinus septations predict the presence of supraorbital ethmoid cells

OBJECTIVES/HYPOTHESIS

This study is undertaken to determine if the presence or absence of multiseptated frontal sinuses is associated with the presence or absence of supraorbital ethmoid cells (SOECs).

STUDY DESIGN

Analysis of prospectively collected data.

METHODS

Sixty consecutive patients with chronic rhinosinusitis were identified from a prospectively collected database at a tertiary-referral institution as having full-sinus computed tomography (CT) scans. Preoperative or initial CT scans of the sinuses were reviewed, specifically identifying the presence or absence of supraorbital ethmoid air cells (SOECS) and frontal sinus multiseptated sections on coronal imaging. Statistical analysis was performed using the chi-squared test to evaluate any association between the two structural entities.

RESULTS

Sixty total patients were identified, for a total of 120 sides. Of the 61 sides with frontal septations, 43 (70%) had SOECs present and 18 (30%) did not. Of the 59 sides without frontal sinus septations, 13 (22%) had SOECs present and 46 (78%) did not (chi squared = 28.3; P = 0.0000001). The difference in the presence of supraorbital ethmoid cells between whites and blacks is also statistically significant (chi squared = 4.23; P = 0.040).

CONCLUSION

The presence of frontal sinus septations appears to be significantly associated with and predictive of the presence of supraorbital ethmoid cells. Thus, identifying frontal sinus septations on sinus CT is implicated with more complex anatomy of the frontal recess.

The association between supraorbital ethmoid air cells and orbital proptosis in patients with chronic rhinosinusitis

BACKGROUND

Orbital proptosis is a known possible complication in patients with chronic rhinosinusitis (CRS). This study was undertaken to determine the association of sinus anatomy and anatomic variants with the predisposition for such a complication.

METHODS

All adult patients (n = 16) with orbital proptosis were identified from a prospectively-collected database at a tertiary institution. These were compared with a series of randomly-selected patients (n = 50) diagnosed with chronic sinusitis and who had undergone sinus computed tomography. The presence or absence of supraorbital ethmoid air cells (SOECs) was noted and compared between the 2 groups. The primary sinus anatomy responsible for the proptosis was also identified. Statistical analysis was performed using the chi squared test.

RESULTS

Sixteen patients with orbital proptosis were identified, of which all but 1 had SOECs present. Causal analysis showed that in all but 1 case the SOECs were the cause of proptosis. Of the 50 patients with CRS but without proptosis, only 13 had SOECs present and 37 patients did not (chi squared = 22.8, p = 0.000002).

CONCLUSION

SOECs appear to be highly associated with and most often are responsible for orbital proptosis in patients with CRS.

Tomografia computadorizada das células etmoidais intra e extramurais: ensaio iconográfico

O desenvolvimento dos seios paranasais é um processo intricado que se inicia na vida intrauterina e termina na idade adulta. Dos seios da face, as células etmoidais são provavelmente as estruturas mais complexas e as que estão associadas com o maior número de variantes da normalidade. Variações no padrão de pneumatização das células etmoidais podem ser divididas em intra ou extramurais. Intramurais são aquelas que ao se desenvolverem mantêm contato com o labirinto etmoidal, e extramurais as que se desenvolvem isoladamente. A tomografia computadorizada é a ferramenta mais útil na avaliação de processos inflamatórios dos seios paranasais. De igual modo, ela é importante para o planejamento pré-operatório e controle pós-operatório, pois possibilita grande detalhe anatômico das estruturas normais e detecção precisa de suas variantes. Neste ensaio iconográfico os autores descrevem as principais variantes da normalidade do labirinto etmoidal e suas relações com estruturas adjacentes. Cirurgias endoscópicas para o tratamento de afecções dos seios paranasais têm-se tornado cada vez menos invasivas, o que certamente aumentará a demanda por relatórios de imagem cada vez mais ricos em detalhes desta região.

Three-dimensional CT reconstruction and virtual endoscopic study of the ostial orientations of the frontal recess

BACKGROUND

Safe and efficient endoscopic frontal sinus surgery requires a thorough knowledge of the location of the frontal sinus outflow tract. This study was designed to describe the prevalence of the different frontal recess cells and 3D analysis by virtual endoscopy of their ostial orientation in relation to the frontal ostium.

METHODS

Fifty high-resolution CT scans (100 sides) of disease-free paranasal sinuses were reviewed using triplanar and virtual 3D analysis. The prevalence and ostial locations of the frontal recess cells and the relationship of the various ostia to the frontal sinus ostium were mapped and analyzed.

RESULTS

The cell type, prevalence, and most common relationship of the cell's ostium to the frontal ostium were intersinus septal cells, 7% medial and anterior; Kuhn type 1 cells, 28%, lateral and anterior; Kuhn type 2 cells, 6%, anterior and lateral; Kuhn type 3 cells, 11%, medial or lateral; supraorbital ethmoid cells, 11%, posterior; suprabullar cells, 68%, posterior; and frontal bullar cells, 16%, posterior or lateral. In 35% of the sides, none of the aforementioned cell types were found. There were many blind recesses that were seen in all locations except anterolateral to the frontal ostium. Openings of adjacent pneumatized middle turbinates were often posteromedial to the frontal ostium. Agger nasi cells were present in at least 86%, opening lateral to frontal ostium.

CONCLUSION

Frontal outflow tract mapping by virtual endoscopy and knowledge of the ostial configurations will help surgeons perform more efficient and accurate surgery particularly for minimally invasive approaches including balloon dilation.

Computed tomographic analysis of frontal recess anatomy and its effect on the development of frontal sinusitis

OBJECTIVES/HYPOTHESIS

To use computed tomography to determine the association of frontal recess cells with the development of frontal sinusitis.

STUDY DESIGN

Retrospective analysis.

METHODS

We retrospectively analyzed various frontal recess cells on spiral computed tomographic images of sinuses between November 2007 and May 2009. Exclusion criteria included previous sinus surgery, sinonasal polyposis, age younger than 18 years, maxillofacial fracture, incomplete sections of computed tomography, and sinonasal malignancy. We used logistic regression analysis to compare the distribution of various frontal recess cells in patients with frontal sinusitis and those without frontal sinusitis.

RESULTS

A total of 192 patients met the criteria, and only 363 sides were distinguishable. The presence of suprabullar cells, supraorbital ethmoid cells, frontal bullar cells, and recessus terminalis was significantly associated with the development of frontal sinusitis by multiple logistic regression models.

CONCLUSIONS

The frequency of frontal recess cells analyzed in Taiwanese adult patients was similar to that analyzed in other Asian adult populations (Chinese and Korean). The frontoethmoid cells posterior and posterolateral to the frontal recess (suprabullar cells, frontal bullar cells, and supraorbital ethmoid cells) might reveal a more significant association with the development of frontal sinusitis than those anterior to the frontal recess (agger nasi cells, frontal cell types 1-3). The presence of supraorbital ethmoid cells on computed tomographic images might indicate the highest odds of frontal sinusitis, followed by the presence of suprabullar cells, frontal bullar cells, and recessus terminalis.