FGF23-secreting sinonasal tumour presenting with acute subdural haemorrhage and tumour-induced osteomalacia.

A female in her 50s developed a headache, collapsed and was noted to have an acute atraumatic subdural haemorrhage (SDH) requiring surgical evacuation and intracranial pressure-directed therapy. Her background included recurrent epistaxis, severe generalised bone pain and multiple insufficiency fractures and an undifferentiated autoimmune connective tissue disease. Chronic hypophosphataemia, elevated alkaline phosphatase and raised fibroblast growth factor 23 (FGF23) were also noted. An MRI head and subsequent 68Ga CT/positron emission tomography scan demonstrated an intensely avid tumour in the right ethmoid sinus, extending intracranially. Phosphate was aggressively replaced, and alfacalcidol was initiated to circumvent the effects of FGF23 on her kidneys and bone minerals. The tumour was biopsied and then definitively resected via combined endonasal and craniotomy approaches, resulting in good clinical improvement. FGF23 titre and serum phosphate both normalised leaving the diagnosis of a phosphaturic mesenchymal tumour-secreting FGF23, leading to tumour-induced osteomalacia.

The Ethmomaxillary Sinus-A False Duplicate Maxillary Sinus.

Functional endoscopic sinus surgery consistently benefits from good anatomical knowledge and modern imaging techniques. Ethmoid air cells migrate in specific topographical sites near the ethmoid. Posterior ethmoid air cells that descend into the maxillary sinus (MS) are ethmomaxillary sinuses (EMSs) that into the superior nasal meatus. Few previous studies found EMSs in 0.68% to 16.48% of cases. An EMS differs from a Haller's infraorbital cell nearing the ethmoidal infundibulum. A posterior ethmoid air cell intercalated between the ethmoid, MS and sphenoidal sinus is a Sieur's cell, but it could also be regarded as an EMS. An EMS should be discriminated from a maxillary recess of the sphenoidal sinus. An EMS could determine Onodi's maxillary bulla into the MS. The false duplicate MS described by Zuckerkandl consists of a MS draining into the middle nasal meatus adjoined by an EMS draining into the superior nasal meatus. These are separated by the ethmomaxillary septum. The latter may be confused with an intrasinus septum of the MS if the drainage pathways are not adequately documented. Therefore, a case-by-case anatomic identification of the pneumatic spaces nearing the MS should be performed before surgical endoscopic approaches of the nose and sinuses.

[Based on CT imaging, surgical approach selection for frontal and ethmoid sinus osteoma].

Objective:To investigate the criteria for selecting surgical approaches for frontal and ethmoid sinus osteomas of different locations and sizes on CT imaging. Methods:Using sagittal and coronal CT images, the following lines were delineated: the F-line（a horizontal line passing nasofrontal beak）, the M-line（a vertical line passing paries medialis orbitae）, and the P-line（a vertical line passing the center of the pupil）. Classification of frontal and ethmoid sinus osteomas was based on their relationship with these lines. Appropriate surgical approaches were selected, including pure endoscopic approaches, endoscopic combined with eyebrow incision approach, and endoscopic combined with coronal incision approach. This method was applied to a single center at the Third Affiliated Hospital of Sun Yat-sen University for endoscopic resection of frontal and ethmoid sinus osteoma. Case Data: Sixteen cases of ethmoid sinus osteomas were treated from January 2020 to September 2023. Among these cases, there were 9 males and 7 females, with ages ranging from 18 to 69 years, and a median age of 48 years. Results:Thirteen cases underwent pure endoscopic resection of the osteoma, while in three cases, a combined approach was utilized. Among the combined approach cases, two exceeded both the M-line and the F-line but did not cross the P-line; therefore, they underwent endoscopic combined with eyebrow incision approach. One case exceeded all three lines and thus underwent endoscopic combined with coronal incision. In all cases, complete resection of the osteoma was achieved as per preoperative planning, and none of the patients experienced significant postoperative complications. Conclusion:For frontal and ethmoid sinus osteomas, it is advisable to perform a thorough preoperative radiological assessment. Based on the size of the osteoma and its relationship to the three lines, an appropriate surgical approach should be chosen to optimize the diagnostic and treatment plan.

Gender differences in ethmoid sinus morphology_ 3D reconstruction of computed tomographic images.

BACKGROUND: The ethmoid sinus (ES) is a three-dimensional (3D) complex structure, a clear understanding of the ES anatomy is helpful to plan intranasal surgery. However, most prior studies use 2D measurements, which may not accurately depict the 3D structure. The current study measured the gender differences in ES morphology based on 3D reconstruction of computed tomography (CT) images. METHODS: The 3D models were reconstructed using CT images. Twenty-one males and 15 females were enrolled in the study. The ES dimensions, including width, height and aspect ratio (AR) of each cutting-plane section, were measured at 10% increments along with the anteroposterior axis of the ES. The gender differences in the above parameters were further evaluated by an independent t-test. RESULTS: The width of the ES for males is 12.0 ± 2.1 mm, which was significantly greater than that in females (10.0 ± 2.1 mm). The average height for males is 18.4 ± 3.5 mm, and 18.2 ± 3.4 mm for females. The AR of female (male) is around 0.56 (0.63) for the anterior ES and 0.66 (0.75) for the posterior. There are significant differences between genders in the parameters of width and AR (p < 0.05). CONCLUSION: This study found that the aspect ratio greatly varies along the length of ES, indicating that the cross-section of the ES in the anterior is closer to an elliptical shape and turns closer to a circular shape near its posterior. There is a significant difference between genders in width and aspect ratio. The results would be helpful to know the complex anatomic details of the ethmoid sinus.

Endoscopically managed giant frontoethmoidal osteoma with orbital extension.

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.

Bilateral sinonasal inverted papillomas originating from both sides of the frontal sinus and the left lamina papyracea: A case report.

RATIONALE: The present investigation documented a case of bilateral sinonasal inverted papilloma (SNIP) that arose from both sides of the frontal sinus and ethmoid sinus. The occurrence of bilateral involvement of the nasal cavities and frontal sinus is rather infrequent. PATIENT CONCERNS: Informed consent was obtained from the patient. DIAGNOSIS: Bilateral SNIP. INTERVENTIONS: The tumor was completely removed by Draf III endoscopic resection complemented by an external eyebrow arch approach, and the postoperative recovery was uneventful. OUTCOMES: The purpose of this paper is to present a comprehensive reference for the management of bilateral SNIP that affects the frontal sinuses. LESSONS: This study addresses the staging and surgical management of bilateral SNIP, along with a review of the factors contributing to its recurrence. The recommended treatment method involves applying the Draf III technique combined with an external nasal approach.

[Cerebrospinal fluid rhinorrhea secondary to ethmoidal carcinoma: case report]. / Rinorrea de líquido cefalorraquídeo secundaria a carcinoma etmoidal: reporte de caso.

BACKGROUND: The first report of cerebrospinal fluid rhinorrhea (CSFR) was described in 1679. In 1826 it was reported that one of the possible causes of CSFR was a fistula between the subarachnoid space and the nasal cavity. In 1903, chemical analysis of the fluid was proposed as a diagnostic criterion. In Mexico there has been 32 case reports. CASE REPORT: Forty-nine years old female with a history of nasal polyposis, profuse rhinorrhea and cephalea who attends the allergy department with the suspicion of allergic rhinitis. After anamnesis and physical evaluation, CSFR was suspected. Chemical analysis of the fluid, head CT and biopsy of nasal polyp were performed. An etmoidal fistula associated with carcinoma was confirmed. CONCLUSIONS: Spontaneous fistulas are rare but can erosionate the bone and adjacent tissues. Diagnosis is based on the clinical findings, patient's history and complementary studies such as beta-2-transferrin determination in nasal fluid.

ANTECEDENTES: En 1679 se describió el primer caso de rinorrea de líquido cefalorraquídeo. En 1826 se reportó como causa una fistula entre el espacio subaracnoideo y la cavidad nasal. Para 1903 se propuso el análisis químico como criterio diagnóstico. En México sólo se han reportado 32 casos de rinorrea de líquido cefalorraquídeo. REPORTE DE CASO: Paciente femenina de 49 años, con antecedente de poliposis nasal, rinorrea abundante y cefalea, quien acudió a consulta para descartar rinitis alérgica. Luego de la anamnesis y la exploración física se sospechó de fuga de líquido cefalorraquídeo secundaria a fístula nasal. Con la histoquímica de moco, tomografía de cráneo y biopsia del pólipo nasal se estableció el diagnóstico de fístula etmoidal secundaria a carcinoma. CONCLUSIÓN: La fístulas espontáneas son excepcionales, pueden erosionar el hueso y los tejidos adyacentes. El diagnóstico se establece con la historia clínica y los antecedentes médicos, además de estudios complementarios y la determinación de Beta-2-transferrina en moco.

Asymmetry of the anterior ethmoidal artery in relation to the anterior skull base: a population-based study of 500 arteries.

OBJECTIVE: To analyze variability in the distance between the Anterior Ethmoidal Artery (AEA) and the anterior Skull Base (SB), as well as the frequency of lateral asymmetry in a Latin American population using computed tomography. METHODS: A total of 250 computed tomography scans of paranasal sinuses in coronal reconstruction (500 AEAs) were analyzed. After determining the image with the best anatomical view of the artery, the distance between its midpoint and the ethmoidal roof was measured, and the images were independently interpreted by 2 physicians. RESULTS: Of the 500 AEAs, 279 (55.8%) adhered to or passed through the SB at a distance of 0mm. A total of 221 AEAs (44.2%) were at some distance from the SB, of which 107 (48.4%) were on the right side, ranging from 1.18 to 6.75mm, and 114 (51.5%) were on the left side, ranging from 1.15 to 6.04mm. The overall mean distance between the AEA and SB was 1.22 (SD=1.57) mm, increasing to 2.77 (SD=1.14) when the arteries adhered to the SB were excluded. Seventy-six individuals (30.4%) had a lateral distance variation > 1mm. CONCLUSION: Our study includes the largest sample of AEA analyzed with computed tomography scans of paranasal sinuses. There was some distance between the AEA and SB in almost half the patients, and we found a high rate of lateral variability >1mm. LEVEL OF EVIDENCE: Level 3.

Evaluation of lamina papyracea dehiscence with paranasal computed tomography.

INTRODUCTION: The lamina papyracea is the thin line between the ethmoid sinus and the medial orbital wall. Knowledge of the presence of the lamina papyracea dehiscence (LPD) bears critical importance to prevent misdiagnosis of fractures at this level and to define the anatomy before sinonasal surgery, including Functional Endoscopic Sinus Surgery (FESS). The present study is therefore intended to determine the incidence of LPD in paranasal computed tomography, to identify its imaging characteristics in CT, and to compare with the literature. MATERIALS AND METHODS: The current study included patients who underwent paranasal CT scanning for any reason in our clinic between January 2018 and January 2022. Patients were evaluated in terms of age, gender, and presence of LPD. Patients with dehiscence were evaluated in terms of age, gender, dehiscence localization (right, left), tissue at the level of dehiscence, dehiscence size, and dehiscence grade. RESULTS: 1000 patients with a mean age of 32. ± 16.3 (min = 18-max = 79) were included in the study. 20 patients (2%) were found to have LPD. Of those with LPD, 14 (70%) were grade 1, 4 (20%) were grade 2 and 2 (10%) were grade 3. Again of those with LPD, 14 (70%) had LPD localized on the right and 6 (30%) had LPD on the left. In 12 (60%) of the patients with LPD, herniated tissue was detected. Among these patients with herniation, fatty tissue herniation was observed in 10 (83.3%) and medial rectus muscle herniation was observed in 2 (16.7%). DISCUSSION AND CONCLUSION: Comprehensive evaluation for and identification of LPD are very important before possible sinus surgery.

Analysis of sphenoid sinus and ethmoid sinus volume and asymmetry by sex: A 3D-CT study.

PURPOSE: To measure the volume of the sphenoid and ethmoid sinuses and to analyse the asymmetry index values by age/gender. METHODS: Three-dimensional (3D) Computed Tomography (CT) images of 150 individuals (75 females, 75 males) of both sexes between the ages of 18-75 were included in our study. Sphenoid and ethmoid sinus volumes were measured using the 3D Slicer software package on these images, and the asymmetry index was calculated. RESULTS: In our study, mean sphenoid sinus volume (female right: 4264.4 mm3, left: 3787.1 mm3; male right: 5201.1 mm3, left: 4818.2 mm3) and ethmoid sinus volume (female right: 3365.1 mm3, left: 3321.2 mm3; male right: 3440.9 mm3, left: 3459.5 mm3) were measured in males and females. Left sphenoid sinus values of males were statistically higher than females (p = 0.036). No statistically significant relationship existed between age, sinus volumes, and asymmetry index (p > 0.05). A statistically weak positive correlation existed between males' left sphenoid and ethmoid sinus volume (rho = 0.288; p = 0.012). There was no statistical relationship between asymmetry index in the whole group (p > 0.05). A statistically weak negative correlation was found between sphenoid and ethmoid sinus asymmetry index in males (rho=-0.352; p = 0.002). There was no statistical relationship between asymmetry index in females (p > 0.05). CONCLUSION: Knowing paranasal sinus morphology, morphometry, and asymmetry index value will be significant for preoperative and postoperative periods.

Severe unilateral refractory epistaxis arising from the septal branch of the anterior ethmoid artery.

KEY POINTS: The septal branch of the anterior ethmoid artery (sbAEA) is an underrecognized source of severe refractory epistaxis. Herein, we describe the presentation, predisposing factors, treatment strategies, and outcomes of a series of patients with this condition.

Transpalpebral/Blepharoplasty Incision and Supraorbital Craniotomy for the Treatment of Ethmoidal Dural Arteriovenous Fistulas: A Case Series.

BACKGROUND AND OBJECTIVES: Inherent complex angioarchitecture associated with ethmoidal dural arteriovenous fistulas (dAVFs) can make endovascular treatment methods challenging. Many surgical approaches are accompanied by unfavorable cosmetic results such as facial scarring. Blepharoplasty incision of the eyelid offers a minimal, well-hidden scar compared with other incision sites while offering the surgeon optimal visualization of pathogenic structures. This case series aims to report an initial assessment of the safety and efficacy of supraorbital craniotomy by blepharoplasty transpalpebral (eyelid) incision for surgical disconnection of ethmoidal dAVFs. METHODS: Retrospective chart review was conducted for all patients who underwent blepharoplasty incision and craniotomy for disconnection of ethmoidal dAVFs at our institution between October 2011 and February 2023. Patient charts and follow-up imaging were reviewed to report clinical and angiographic outcomes as well as periprocedural and follow-up complications. RESULTS: Complete obliteration and disconnection of ethmoidal dAVF was achieved in all 6 (100%) patients as confirmed by intraoperative angiogram with no resulting morbidity or mortality. Periprocedural complications included one case of transient nasal cerebrospinal fluid leak that was self-limiting and resolved before discharge without intervention. CONCLUSION: Surgical treatment for ethmoidal dAVFs, specifically by transpalpebral incision and supraorbital craniotomy, is a safe and effective treatment option and affords the surgeon greater access to the floor of the anterior fossa when necessary. In addition, blepharoplasty incision addressed patient concerns for facial scarring compared with other incision sites by creating a more well-hidden, minimal scar in the natural folds of the eyelid for patients with an eyelid crease.

The tortuous course of the anterior ethmoidal artery in the orbit: A cadaveric study.

AIM: The study aimed to define the coursing pattern of the anterior ethmoidal artery (AEA) in the orbit to minimize complications during endoscopic interventions. MATERIALS AND METHODS: A total of ten formalin-fixed cadaveric halves were included in the study. Orbital regions were shown with a superior approach. The superior rectus and superior oblique muscles, as well as the connective tissue and vessels were removed to observe the path of the anterior ethmoidal artery. Measurements such as the width of the artery, the anterior-posterior length of the U formation, the length of the intraorbital part of the ophthalmic artery, and the distance of the AEA from its opthalmic origin to the anterior ethmoidal foramen were made. RESULTS: Ten of the AEAs originated from the ophthalmic artery. The AEA branches originated from the ophthalmic artery approximately 18.4 mm after the orbital artery entered the orbital, and the mean width of the AEAs was 0.82 mm. In seven of the total anterior ethmoidal arteries, they coursed in the intraethmoidal cavities below the cranial base. The mean distance from the origin of AEAs to the medial wall of the orbit was 4.9 mm. After leaving the ophthalmic artery, seven of the AEAs were coursing forward and turned back ('U' turn formation), which have proximately 1.5 mm in anteroposterior direction. CONCLUSION: The anterior ethmoidal artery is 0.8 mm wide, originates from the distal part of the ophthalmic artery, entering the orbit after a 1.5 mm U-turn.

Are the Ethmoidal Foramina Through the Frontal Bone, Ethmoid Bone, or Frontoethmoidal Suture?

INTRODUCTION: To investigate the locations of the anterior, middle, and posterior ethmoidal foramina and their relationships to the frontoethmoidal suture. METHODS: One hundred twenty sides from sixty adult human skulls were used. Specimens with significant damage to the medial orbit wall were excluded. The number of ethmoidal foramina (anterior, middle, and posterior) on the medial orbital wall and the relationship of each foramen to the frontoethmoidal suture were recorded and classified as follows: Type I: superior to the frontoethmoidal suture; Type II: on the frontoethmoidal suture; Type III: inferior to the frontoethmoidal suture. RESULTS: Of the ninety-four sides, fourteen (14.9%) had one foramen, sixty-two (66.0%) had two , and eighteen (19.1%) had three. In total, 192 ethmoidal foramina were observed. Among the fourteen sides with one foramen, eight foramina were anterior and six were posterior. Among the 192 ethmoidal foramina, 162 were eligible for fur ther classification (74 anterior, 14 middle, and 74 posterior). Types I, II, and III ethmoidal foramina were found in 38.3% (62/162), 61.7% (100/162), and 0% (0/162), respectively. CONCLUSIONS: Our current study found a higher incidence of type I than previously reported. It is important to be aware of the significant incidence of foramen variations when the medial orbit wall is manipulated during surgery. Unless caution is observed, an inadvertent surgical injury can occur and lead to life-threatening complications. Therefore, a good understanding of orbital anatomy and its potential variations is critical for improving patient out comes.

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.

Impact of facility volume on survival in primary endoscopic surgery for sinonasal squamous cell carcinoma.

OBJECTIVES: To evaluate the impact of facility volume on outcomes following primary endoscopic surgical management of sinonasal squamous cell carcinoma (SNSCC). METHODS: The 2010-2016 National Cancer DataBase (NCDB) was queried for patients diagnosed with T1-T4a SNSCC surgically treated endoscopically as the primary treatment modality. Factors associated with overall survival (OS) were evaluated, including facility volume. RESULTS: A total of 330 patients who underwent endoscopic surgical management of SNSCC were treated at 356 unique facilities designated as either low-volume (LVC; treating 1-2 cases; 0-75th percentile), intermediate-volume centers (IVC; 3-4 cases total; 75th-90th percentile), or 144 high-volume (HVC; treating 5+ cases total; >90th percentile) centers. HVC treated patients with higher T staging (42.1 % vs. 29.8 %) and tumors in the maxillary sinus (26.9 % vs. 13.2 %) and ethmoid sinus (10.3 % vs. ≤8.3 %), while LVCs treated lower T stage tumors (70.2 % vs. 57.9 %) and tumors that were located in the nasal cavity (70.2-78.5 % vs. 62.8 %). On multivariable analysis, factors associated with decreased OS included higher T stage (T3/T4a vs. T1/T2; OR 1.92, 95 % CI 1.06-3.47) and older age (>65 vs. <65; OR 2.69, 95 % CI 1.62-4.49). Cases treated at high-volume centers were not associated with a higher likelihood of OS when compared to low-volume centers (OR 0.70, 95 % CI 0.36-1.35). CONCLUSIONS: HVC are treating more primary tumors of the maxillary and ethmoid sinuses and tumors with higher T stages with endoscopic approaches, although this does not appear to be associated with increased OS. SHORT SUMMARY: Sinonasal squamous cell carcinoma (SNSCC) presents late in disease process with poor prognosis. We investigated the impact of facility volume on outcomes following endoscopic treatment of SNSCC. High-volume centers treat more advanced and complex disease with comparable OS.

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.

Computed tomography assessment of maxillary sinus hypoplasia and associated anatomical variations: a systematic review and meta-analysis of global evidence.

OBJECTIVE: To summarize the scientific evidence on the prevalence of maxillary sinus hypoplasia (MSH) and associated anatomical variations as assessed by computed tomography scans. STUDY DESIGN: This PROSPERO-registered systematic review followed the recommendations of the PRISMA guidelines. Search algorithms were constructed for each of the six databases and gray literature. After screening the references (Rayyan®), the extracted data were meta-analyzed according to a random-effects model. The joanna briggs critical appraisal tool assessed the methodological quality of the included studies. The GRADE approach was used to estimate the certainty of the evidence. RESULTS: From a total of 2781 studies screened, 22 were considered for four meta-analysis. The prevalence of MSH in 7358 patients was 5.65% (CI95% = 4.07-7.47%) with significant heterogeneity between studies (p < 0.001, I2 = 89.30%). MSH was identified in 295 patients, of whom 82.38% (CI95% = 75.82-88.09%) had unilateral hypoplasia and 17.62% (CI95% = 11.91-24.18%) bilateral hypoplasia with moderate heterogeneity between studies (p < 0.0503, I2 = 42.87%). The prevalence of MSH in 9998 maxillary sinuses was 3.77% (95% CI = 2.44-5.38%), with significant heterogeneity between studies (p < 0.001, I2 = 92.84%). Hypoplastic/aplastic uncinate process, concha bullosa and paradoxical concha were the most reported anatomical variations. The studies presented a low-moderate methodological quality. The certainty of the evidence was very low to moderate. CONCLUSION: The prevalence of maxillary sinus hypoplasia observed was 5.65%, with most cases being unilateral.

The Upper Attachment of the Uncinate Process and Anterior Ethmoidal Artery.

OBJECTIVE: Variations in the upper attachment of the uncinate process (UP) are important because they can affect frontal sinus drainage and change the morphology. Functional endoscopic sinus surgery (FESS) is the primary technique used to treat chronic medically refractory rhinosinusitis. Uncinectomy is the basis of FESS technique to obtain the best possible result from surgery. The anterior ethmoidal artery (AEA) enters the nasal cavity through the orbital medial wall (lamina papyracea) may also be affected by the upper attachment of the UP. The aim of this study was to investigate a possible link between UP variations and the course of the AEA. MATERIALS AND METHODS: This retrospective, computed tomography (CT)-based, anatomic study was conducted on 200 healthy adults (100 females and 100 males) by screening bilateral paranasal sinus images. The upper attachment of the UP was classified in 6 types (1-6) based on the Liu classification. The AEA was divided into 4 types (A-D) based on location: anterior to the frontal sinus (A), between the frontal sinus and the middle nasal turbinate (B), and anterior to the posterior ethmoidal cells (C and D). All the CT images were evaluated simultaneously by 2 anatomists and 1 radiologist. RESULTS: Of the total cases (200 right and 200 left side), 48.8% were type 1 UP attachment, 11.0% type 2, 12% type 3, 9% type 4, 18% type 5, and 1.2% type 6. The AEAs were classified as 12.2% type A, 71.8% type B, 15.2% type C, and 0.8% type D. CONCLUSION: The course of the AEA through the nasal cavity was observed to shift anteriorly from the ethmoidal bulla to the frontal sinus in patients with UP attached to the lamina papyracea and middle turbinate. Remarkably, the AEA always coursed anterior from the middle nasal turbinate line.

A Consistent Endoscopic Landmark to Identify the Anterior Ethmoidal Artery.

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