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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.

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Retromaxillary cell (RMC), one of the anatomical variations of the posterior ethmoidal cell and is often overlooked during primary functional endoscopic sinus surgery. The incomplete removal of the disease from RMC leads to need for revision surgery. This study was aimed at analyzing Computed tomography scans of patients' paranasal sinuses for the incidence, types and radiological evaluation of Retromaxillary cell. Incidence of RMC was 74% (74/100 sides). The sex distribution was 31 (62%) males and 19 (38%) females. 34 patients (85%) had bilateral RMC and 6 patients (15%) had unilateral RMC. Lateral extension of RMC ranged from 1.03 to 11.3 mm. Out of 74 sides examined, 20 (27.02) were type I, 36 were type II (48.64%) and 18 (24.32%) were type III. The incidence of maxillary sinus disease on RMC sides and non-RMC sides has no significant difference (p < 0.5). RMC is lateral extension of posterior ethmoidal cell beneath the orbit and posterosuperior to maxillary sinus. The depth of the RMC is highly variable. The risk of residual disease in FESS is high in Type III RMC and one should pay attention to presence or absence of RMC and type of RMC prior to the endoscopic sinus surgery. Radiological study of RMC helps in preoperative planning and therefore intraoperative complete clearance of disease in endoscopic sinus surgery.

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OBJECTIVE: To establish the prevalence and individual variations of the ethmomaxillary sinus (EMS) using cone beam computed tomography (CBCT). MATERIAL AND METHODS: CBCT images from 553 dental and ENT patients (1106 sides), presenting to treatment at Minsk outpatient clinics, Belarus, were used in this study. The maximum vertical diameter of ethmomaxillary sinus in the coronal plane was measured. Anatomical variations of the ostiomeatal complex and mucosal diseases of paranasal sinuses were recorded. RESULTS: Ethmomaxillary sinus - is posterior ethmoidal cell extending to the posterior superior part of the maxillary sinus (MS) while draining into superior meatus. It was present in 13 of 553 patients (2.4%). The age of patients with EMS ranged from 12 to 60 years, including 8 males and 5 females. A total of 5 patients had unilateral EMS and 8 patients - bilateral EMS. Ethmomaxillary sinus was extended to the alveolar bone in five cases. Moreover, in two cases, the roots of the upper third molars protruded into its lumen. CONCLUSION: The enlarged posterior ethmoidal air cell can occupy the posterior superior portion of the maxillary sinus and even reach the alveolar bone. Such a cell is called the ethmomaxillary sinus and, as a rule, its presence is accompanied by excessive pneumatization of other cranial bones. Inflammation of the mucous membrane of the ethmomaxillary sinus is most often not combined with the radiographic signs of maxillary sinusitis, and a direct communication of the EMS and MS was detected in only one patient.

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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.

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Objective: To investigate the prevalence and radiographic characteristics of ethmomaxillary sinus (EMS) in chronic rhinosinusitis (CRS) patients by CT scan, as well as their endoscopic surgical significance in antrostomy. Methods: A retrospective analysis of 111 CRS patients who were prepared for surgery in Department of Otorhinolaryngology Head and Neck Surgery of Peking University People's Hospital from February to December of 2017 was performed. In all CRS patients, 79 patients were bilateral CRS and 32 were unilateral. The patients were divided into two groups according to whether they had history of surgery. Only the sides with CRS were analyzed. There were 98 patients (167 sides) in the non-surgical history group and 13 patients (23 sides) in the surgical history group. The prevalence of EMS in CRS sides in the two groups was counted by analyzing the CT images. The CT image features and anatomical variations associated with EMS in CRS sides in the non-surgical history group were also analyzed. SPSS 22.0 software was used for statistic analysis. Results: The prevalence of EMS in CRS sides was 21.7% (5/23) in the surgical history group and 12.0% (20/167) in the non-surgical history group. No statistically significant difference in the prevalence of EMS was found between the two groups (χ(2)=0.940, P>0.05). The medial-lateral diameters of the EMS ranged from 8.50 to 14.10 mm with an average of (10.38±1.69) mm (Mean±SD). The shape of the bony septum between the EMS and maxillary sinus was divided into three types: convex toward to the EMS (2 sides), convex toward to maxillary sinus (5 sides) and flat (13 sides). The Lund-Mackay (LM) scores of the maxillary sinuses in patients with and without EMS showed no statistically significant difference (1.60±0.50 vs 1.40±0.62, Z=1.285, P>0.05). The EMS obstructed the drainage of maxillary sinus posteriorly, medially and superiorly. All the EMS in diseased sides were dissected endoscopicly to improve drainage. In the non-surgical history group, the EMS coexisting anatomic variations were the Onodi cell (7/20), Haller cell (3/20), concha bullosa (6/20) and maxillary sinus hypoplasia (3/20). Conclusions: There is relatively high prevalence of the EMS in CRS patients. This is adjacent to the orbit, overpneumatizes laterally and obstructs the drainage of the maxillary sinus. Complete dissection of the EMS is helpful to improve the drainage of maxillary sinus.

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Objective@#To investigate the prevalence and radiographic characteristics of ethmomaxillary sinus (EMS) in chronic rhinosinusitis (CRS) patients by CT scan, as well as their endoscopic surgical significance in antrostomy.@*Methods@#A retrospective analysis of 111 CRS patients who were prepared for surgery in Department of Otorhinolaryngology Head and Neck Surgery of Peking University People′s Hospital from February to December of 2017 was performed. In all CRS patients, 79 patients were bilateral CRS and 32 were unilateral. The patients were divided into two groups according to whether they had history of surgery. Only the sides with CRS were analyzed. There were 98 patients (167 sides) in the non-surgical history group and 13 patients (23 sides) in the surgical history group. The prevalence of EMS in CRS sides in the two groups was counted by analyzing the CT images. The CT image features and anatomical variations associated with EMS in CRS sides in the non-surgical history group were also analyzed. SPSS 22.0 software was used for statistic analysis.@*Results@#The prevalence of EMS in CRS sides was 21.7% (5/23) in the surgical history group and 12.0% (20/167) in the non-surgical history group. No statistically significant difference in the prevalence of EMS was found between the two groups (χ2=0.940, P>0.05). The medial-lateral diameters of the EMS ranged from 8.50 to 14.10 mm with an average of (10.38±1.69) mm (Mean±SD). The shape of the bony septum between the EMS and maxillary sinus was divided into three types: convex toward to the EMS (2 sides), convex toward to maxillary sinus (5 sides) and flat (13 sides). The Lund-Mackay (LM) scores of the maxillary sinuses in patients with and without EMS showed no statistically significant difference (1.60±0.50 vs 1.40±0.62, Z=1.285, P>0.05). The EMS obstructed the drainage of maxillary sinus posteriorly, medially and superiorly. All the EMS in diseased sides were dissected endoscopicly to improve drainage. In the non-surgical history group, the EMS coexisting anatomic variations were the Onodi cell (7/20), Haller cell (3/20), concha bullosa (6/20) and maxillary sinus hypoplasia (3/20).@*Conclusions@#There is relatively high prevalence of the EMS in CRS patients. This is adjacent to the orbit, overpneumatizes laterally and obstructs the drainage of the maxillary sinus. Complete dissection of the EMS is helpful to improve the drainage of maxillary sinus.

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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.

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OBJECTIVE: Retromaxillary pneumatization of posterior ethmoid (PE) air cells is an area that is yet to have appropriate description in rhinologic literature. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care hospital. SUBJECTS AND METHODS: First, 524 sides in 262 paranasal sinus computed tomography scans were analyzed: 350 normal sides were examined for PE pneumatization lateral to the sagittal plane of the medial wall of maxillary sinus posteriorly, and 174 diseased sides were similarly reviewed to check how pathology may affect identification and measurements. Following that, 153 operated sides in 84 cases prepared for revision endoscopic sinus surgery (ESS) were studied for residual diseased cells at different anatomic locations. RESULTS: Overall, retromaxillary PE pneumatization was identifiable in 416 of the 524 sides (79.4%). Lateral retromaxillary extension varied from 0.5 to 12.3 mm (mean ± SD, 4.8 ± 2.3 mm). This area of pneumatization is bounded anteroinferiorly by the junction between the posterior and superior walls of the maxillary sinus. Three cell types were described depending on the degree of lateral extension (type I, <3 mm; type II, 3-6 mm; type III, >6 mm). This cell, which we refer to as the Herzallah cell, was distinguishable from the anterior ethmoid Haller cell and was found to have residual disease in 50.3% of cases prepared for revision ESS. CONCLUSION: Retromaxillary extension of PE air cells varies considerably and requires attention during ESS. Residual undissected retromaxillary cell is a common finding in revision ESS and can contribute to inadequate disease clearance.

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