Sinus Pneumatisation and Keros Type as Predictors of Anterior Ethmoidal Artery Configuration: A 3D-Reconstructed Computed Tomography Analysis

Background/Objectives: Anatomical variation in the ethmoid roof and lateral lamella play an important role in anatomical vulnerability during endoscopic sinus and skull base surgery. However, widely used classifications, including the Keros system, primarily focus on vertical depth and may not fully reflect the complex geometric relationship between the ethmoid roof, lateral lamella, and the anterior ethmoidal artery (AEA). This study aimed to characterize ethmoid roof and lateral lamella anatomy using high-resolution CT and to propose a descriptive radiological framework—the Akcan Classification—that integrates AEA exit patterns with multiple morphometric parameters. Given the complexity of thin skull base structures, interobserver reproducibility of all morphometric parameters was additionally assessed to ensure measurement robustness. Methods: High-resolution paranasal sinus CT scans from 175 adults (350 sides) were retrospectively evaluated. Measurements included ethmoid roof width, lateral lamella depth, anterior–posterior length, lamellar angle, AEA–lamella distance, and sinonasal anatomical variations. Interobserver reliability was quantified using ICCs. AEA morphology was categorized as in-canal (Type 1), partially suspended (Type 2), or fully suspended (Type 3) based on radiological appearance of bony canalization. Appropriate statistical tests were used to compare morphometric features across groups. Results: Suspended AEA configurations demonstrated progressively wider ethmoid roofs, deeper lateral lamellae, steeper lamellar inclination, and shorter AEA–lamella distances (all p < 0.001). Supraorbital ethmoid cells were more frequently observed in Type 3 cases (p < 0.001). Other anatomical variations showed no significant association with ethmoid roof morphology. Interobserver reliability was excellent for all measurements (ICC range 0.87–0.94). Conclusions: The findings suggest that AEA configuration is associated with broader patterns of ethmoid roof and lateral lamella morphology. Rather than serving as a validated predictor of surgical outcomes, the Akcan Classification provides a structured anatomical and radiological descriptor that complements depth-based systems such as the Keros classification. The high reproducibility of measurements supports its potential utility for standardized anatomical assessment and preoperative radiological interpretation, while further studies incorporating surgical correlation are required.

ABSTRACTBackgroundFrontal base mixed pial‐dural arteriovenous malformations (MPD‐AVMs) are rare intracranial vascular malformations with both pial and dural components. Although they share some angioarchitectural similarities with anterior cranial fossa dural arteriovenous fistulas (ACF‐DAVFs), the two represent different pathological processes, as ACF‐DAVFs are supplied exclusively by dural arteries. This study provides an overview of frontal base MPD‐AVMs, highlighting their differences from ACF‐DAVFs, and discusses the therapeutic implications of their distinct angioarchitectural features.MethodsThis is a single‐center case series study conducted between January 2018 and December 2024. The data of 11 patients who underwent endovascular treatment for frontal base MPD‐AVMs and 29 patients diagnosed with ACF‐DAVFs were retrospectively reviewed.ResultsIn patients diagnosed with MPD‐AVMs, all lesions were supplied by the anterior ethmoidal artery (AEA) and orbitofrontal artery (OFA). Flow‐related aneurysms in the OFA were identified in seven patients (7/11, 63.6%), with three presenting with hemorrhagic events. Treatment approaches included transarterial embolization (TAE) in eight patients, with one requiring additional transvenous embolization (TVE). Primary TVE was employed in three patients, including two hemorrhagic patients who underwent staged treatment with initial aneurysm embolization. Complete obliteration was achieved in 72.7% of cases (8/11), although one patient experienced postoperative hemorrhage. In patients presenting with ACF‐DAVFs, venous aneurysm (18/29, 62.1%) might represent a risk factor for bleeding (13/29, 44.8%) (p = 0.003). In the MPD‐AVM group, venous aneurysms were detected in five patients (5/11, 45.5%), but none of whom experienced hemorrhage.ConclusionFrontal base MPD‐AVMs represent distinct vascular anomalies from ACF‐DAVFs, often featuring anterior cerebral artery branch involvement. Tailored multi‐arterial endovascular strategies are crucial for optimizing outcomes and minimizing complications. Further studies with larger cohorts are essential to validate these observations and refine treatment guidelines.

Nasal septal perforation (NSP) repair has evolved with the development of advanced techniques like the anterior ethmoidal artery (AEA) and greater palatine artery (GPA) flaps, achieving high success rates. Traditional challenges in combining NSP repair with rhinoplasty stem from the reliance on mucoperichondrial blood supply for graft survival and the risks of cartilage absorption or infection during exposure of the L-strut framework. This article presents modified "racket-on-donut" and "boot-on-donut" techniques for simultaneous NSP repair and rhinoplasty, incorporating innovations to bilaterally cover grafts with mucosal flaps and reconstruct the dorsal L-strut under a preserved dorsum. Case 1 involved a 62-year-old patient with an anterior NSP and structural deformities. The modified "racket-on-donut" flap was used to cover the perforation and the septal replacement graft bilaterally, ensuring functional and aesthetic correction. Case 2 featured a 65-year-old patient with a larger NSP and thin skin. Using the modified "boot-on-donut" flap, the NSP was repaired, and dorsal preservation maintained keystone area integrity. Both cases utilized open rhinoplasty to optimize access, facilitate flap mobilization, and enhance mucosal recruitment. The combined approach offers superior outcomes by addressing functional and aesthetic issues in a single procedure, reducing complications like graft necrosis and septal reperforation. Preservation rhinoplasty, traditionally contraindicated in NSP repair, proved effective with careful reconstruction of the L-strut and keystone area preservation. These techniques provide a versatile solution for complex NSP cases, integrating pedicled flaps with reconstructive rhinoplasty to achieve durable, aesthetic and functional results.

Objective:To investigate the CT image characteristics of anterior ethmoidal artery（AEA） through CT scan and its significance in nasal endoscopic surgery. Methods:A retrospective study of 82 patients（164 sides） with chronic sinusitis was conducted. All patients underwent CT scan and the images were reconstructed. The AEA classification was used and calculate the rate of AEA suspension. The AEA was classified, and the suspension rate of the AEA was calculated. The height of the lateral lamella of the cribriform plate （LLCP） was measured, and Keros classification was performed. The relationship between Keros classification and AEA suspension was analyzed. The supraorbital ethmoidal cell （SOEC） was identified, and its relationship with AEA suspension was analyzed. Results:Type Ⅰ AEA accounted for 42.07%（69/164）. Type Ⅱ AEA accounted for 22.56%（37/164）. Type Ⅲ AEA accounted for 35.37%（58/164）. The suspension rate was 35.37%. The average height of the LLCP was （3.7±1.8） mm. In the Keros classification, type Ⅰaccounted for 53.05%（87/164）, Type Ⅱaccounted for 37.80%（62/164）. Type Ⅲ accounted for 9.15%（15/164）. The results of the Spearman analysis showed that there was a moderate positive correlation between the Keros classification and the suspension of the AEA（r=0.526, P<0.01）. Among 164 sides, SOEC was present in 15 sides. The suspension rate of AEA in the group with SOEC was significantly higher than that in the group without SOEC（P<0.01）. Conclusion:Sinus CT and multiplanar reconstruction can clarify the image characteristics of AEA and its relationship with surrounding structures. When the level of Keros classification is higher or SOEC is present, the suspension rate of AEA increases significantly. It is of great significance to clarify the characteristics of AEA before surgery in order to avoid injury during surgery.

Objective: To investigate the anatomical feasibility of the endoscopic transorbital approach (ETOA) to the orbital apex and lateral middle cranial fossa, to identify stable and recognizable surgical landmarks under endoscopic visualization, and to provide morphometric data for preoperative planning and intraoperative navigation. Methods: Stepwise anatomical dissection was performed on five formalin-fixed cadaveric heads and one fresh arterially injected cadaveric specimen to simulate the ETOA using a 0° endoscope. Key structures and their anatomical relationships were observed and recorded. Additionally, high-resolution CT scans of 50 adults were retrospectively analyzed. Three-dimensional reconstructions and measurements were performed using Mimics 17.0 software. Spatial validation was performed using 17 dry skulls to verify the consistency and reliability of osseous anatomical landmarks. Results: Cadaveric dissection identified the meningo-orbital band, superior orbital fissure, optic canal, foramen rotundum, and foramen ovale as reliable surgical landmarks for the ETOA. A topographic map of the surgical region was established based on the endoscopic view. CT measurements revealed the following distances (Mean±SD): the midpoint of the supraorbital rim to the foramen rotundum (57.31±3.59) mm and foramen ovale (71.46±3.42) mm; the lateral orbital rim to the lateral edge of the superior orbital fissure (37.38±2.52) mm; the distance from the superior orbital fissure to the optic canal (9.98±1.49) mm; and the distance from the anterior ethmoidal artery to the optic canal (19.98±2.05) mm. These measurements were consistent with dry skull data, indicating that these osseous landmarks had stable spatial relationships and were suitable for intraoperative localization. Conclusions: The ETOA provides favorable anatomical accessibility and clinical feasibility for lesions involving the orbital apex and lateral skull base. Key osseous structures demonstrate high identifiability and stable spatial relationships, serving as critical references for intraoperative navigation and preoperative pathway planning. The quantitative anatomical framework established in this study provides critical morphometric support for minimally invasive surgery targeting lesions in this region.

Data that compare the anterior ethmoidal artery (AEA) with the sphenopalatine artery (SPA) in epistaxis are limited. We intended to compare features of idiopathic epistaxis due to the anterior ethmoidal artery (AEA-epistaxis) with features of idiopathic epistaxis due to the sphenopalatine artery (SPA-epistaxis). We conducted a retrospective review of subjects that were hospitalized due to epistaxis between 1st January 2017 and 31st December 2024 at the University Department of Otorhinolaryngology. In 113 subjects with idiopathic epistaxis, 61 (54%) subjects presented with SPA-epistaxis and 27 (24%) with AEA-epistaxis. The most frequent AEA-epistaxis site was the Stamm's S point (23/27), with the anterior nasal roof following (4/27). Subjects with SPA-epistaxis needed less often (13%) blood transfusion compared to subjects with AEA-epistaxis (30%; p < 0.001). Type of anesthesia differed significantly between subjects with SPA-epistaxis (100% general anesthesia) and subjects with Stamm' S point AEA-epistaxis (30% local anesthesia; p < 0.001). More subjects with initial SPA-epistaxis were re-admitted with severe epistaxis on the same nasal side (4.9%) than subjects with initial AEA-epistaxis (0%; p > 0.2). In every fourth patient, idiopathic epistaxis might originate from septal branches of AEA, i.e., the Stamm's S point or the anterior nasal roof. Otorhinolaryngologists should not neglect looking for AEA branches during epistaxis. Delay of identification might result in higher blood transfusion rates. In contrast to the SPA, Stamm's S point can be occasionally addressed under local anesthesia, with very low re-admission rates.

Expanded frontal sinusotomies (Draf IIb/c-III) are essential surgical procedures for managing complex frontal sinus pathologies. However, traditional anatomical landmarks may be difficult to identify, particularly in tumor or revision cases. This manuscript investigates the nasal branch of the anterior ethmoidal artery (NbAEA) and the cribroethmoidal groove (CrEGr) as reliable and consistent landmarks for endoscopic frontal sinusotomies. This study included anatomical dissections (medio-lateral approach) on three fresh cadavers (six sides) focused on the region anterior to the first olfactory phylum, namely the cribo-frontal area. Additionally, a retrospective clinical case series of patients that underwent centripetal dissection with a medio-lateral approach to the frontal sinus was performed. Identification of NbAEA, CrEGr, and the first olfactory phylum, along with surgical outcomes and complications, was analyzed. The NbAEA and CrEGr were identified in all dissected sides and were located anterior to the first olfactory phylum. Considering the 19 enrolled patients, 13/19 (68.4%) were treated with a bilateral centripetal dissection and Draf III procedure (26 sides); whereas 6/19 patients (31.6%) underwent a unilateral approach with a Draf IIb/c procedure. The NbAEA and CrEGr were identified in all cases (100%) and in only 9/19 cases (47.7%) the first olfactory phylum was additionally exposed, reinforcing the role of these new anatomical landmarks. No perioperative complications were recorded. This study supports the clinical significance of NbAEA and CrEGr as reliable anatomical landmarks, and their identification in 100% of cases reinforces their practical applicability in surgical approaches to the frontal sinus. Level 4.

To describe a novel flap, the anteriorly based middle turbinate flap (ABMTF), via a cadaveric dissection, as well as present our experience using the ABMTF in 13 patients. Cadaver dissection study demonstrating methodology of harvesting the ABMTF. Retrospective chart review of 13 patients from a tertiary rhinology referral center undergoing CSF leak repair using the ABMTF from January 2017 to August 2023. Five cadaveric specimens were utilized to complete the dissection of the ABMTF. Flap dimensions and surface area were measured. A step-by-step surgical technique was recorded to illustrate a video demonstration. Demographic data, BMI, pre and postoperative SNOT 22 scores, size and location of the skull base defect, and flap measurements on computed tomography (CT) were obtained from the electronic medical record. Five ABMTF were dissected and showed a mean flap surface area for the medial ABMTF of 3.45 cm2 with a range of 2.5 to 4.46 cm2 and a mean surface area for the lateral ABMTF of 2 cm2. The mean surface area of the flap on CT scan measurements was 3.46 cm2. Twelve patients were female, with an average BMI of 35.1 kg/m2. Ten out of 13 patients were treated post-operatively with acetazolamide for management of presumed intracranial hypertension. Postoperative SNOT 22 scores significantly improved at the last follow up visit. All patients had excellent flap tissue integration at their latest follow up with no postoperative CSF leak. The ABMTF is a novel random flap, vascularized by branches of the anterior ethmoid artery, that is effective in skull base reconstruction and CSF leak repair emanating from the anterior skull base between the frontal recess and the posterior ethmoid artery along the ethmoid roof. This flap is versatile with limited morbidity.

BackgroundMinimally invasive techniques for the resection of sinonasal masses have become increasingly important over the past few decades. Sinonasal disease involving the lamina papyracea remains difficult to manage given the risk of injury to critical orbital structures and hemorrhage from nearby vessels.ObjectiveDetail the transcaruncular approach with orbital protection for the resection of benign and malignant sinonasal pathologies.MethodsDescription of surgical technique and presentation of 2 representative cases that were successfully managed with this surgical technique.ResultsThe transcaruncular approach involves incising the lateral 1/3 of the caruncle in a vertical plane between the upper and lower puncta. Dissection is then carried through the retrocaruncular fascia posterior to Horner's muscle to the posterior lacrimal crest along the medial orbital wall. Dissection can then be performed in a subperiosteal or supraperiosteal plane with subsequent ligation of the anterior ethmoidal artery. Once dissected, a nylon sheet used for orbital reconstruction and colored orbital shield can then be placed to aid in protection and visualization or orbital contents during endonasal tumor resection.ConclusionThe transcaruncular approach with orbital protection provides intraoperative protection of the orbital contents, allowing for safer removal of the mass irrespective of integrity of the lamina papyracea.

The arteries supplying the nasal septum and the lateral wall of the nose include vessels that originate from the external carotid artery and the internal carotid artery. Endonasal mucosal pedicle flaps located in the upper parts of the nasal cavity can be used for plastic surgery on the nasal septum. The main flaps are supplied with blood by the terminal branches of the cuneiform-palatine artery and the anterior ethmoid artery, these same branches are involved in the formation of Kisselbach–Little area in the lower third of the nasal cavity. The aim of the study was to study the opportunities of ultrasound examinations of Kisselbach–Little area in predicting viability of relocatable endonasal mucosal flaps to close the perforated foramen of the nasal septum. Materials and methods. In 2022–2025, 56 subjects were examined at the Autonomous Public Health Care Institution «Republican Clinical Hospital» under the Health Ministry of the Republic of Tatarstan, 20 of them had no pathology of the nasal septum (control group), 36 had perforation of the nasal septum (20 women, 16 men aged 18 to 52 years). Ultrasound examination of Kisselbach–Little area was performed using SUPERSONIC AIXPLORER (France) and RESONA 7 (Mindreuil, China) scanners with linear sensors with a frequency of 10-16 MHz. Duplex color scanning revealed a network of blood vessels above, near and below the perforated foramen of the nasal septum. The maximum and minimum blood flow rates and the resistance index in the arterial vessels of Kisselbach–Little area were determined. Results. In control group subjects, maximum blood flow velocity in the arterial vessels of Kisselbach–Little area reached 15-35 cm/s, the resistance index was 0.5–0.59 units. A decrease in the maximum blood flow velocity (less than 15 cm/s) and an increase in the resistance index (more than 0.59 units) are significantly associated with an increased risk of necrosis of the displaced endonasal flap to close the perforated foramen of the nasal septum. Conclusions. Ultrasound examination in color duplex scanning mode makes it possible to determine the hemodynamic parameters of arterial vessels in Kisselbach–Little area. Hemodynamic parameters of arterial vessels in Kisselbach–Little area make it possible to assess the blood supply to potentially displaced endonasal mucosal flaps to close the perforated foramen of the nasal septum and predict their engraftment.

Introduction: The frontal sinus evacuates its contents through the frontal recess, which is surrounded by frontoethmoidalair cells. Among the reasons for failure in endoscopic sinus surgery is incomplete clearance of diseased air cells around thefrontal recess. Detailed knowledge of the tomographic-anatomical variants within the frontal recess is essential. Objective:To evaluate the frequencies of tomographic-anatomical variants within the frontal recess in a sample of patients fromPeru during 2022. Materials and Methods: A retrospective cross-sectional descriptive observational study in which 201paranasal sinus tomographies were evaluated, including the evaluation of 402 frontal sinuses and their recesses, whichwere taken from the year 2022. Results: The most common frontoethmoidal cell was the agger nassi cell with a frequencyof 98. 5%, while the least common was the supra agger frontal cell (13.9%). The anterior ethmoidal artery was evidentas pendant in 61.7% and the most frequent AP distance on the right side was &lt;5 mm and on the left side it was 5mm-10mm. Conclusions: To safely perform a surgical approach to the frontal sinus, tomographic and anatomical knowledgeof the frontal recess is essential due to the different variants that are common in our Peruvian population. This work willcontribute to a better understanding by Peruvian surgeons of this region, which is difficult to access surgically.ontribute toa better understanding among Peruvian surgeons of this region studied, which is difficult to access surgically.

Nasal bleeds, anterior or posterior necessitate varied stepladder interventions like the simple thumb-index finger pinch technique, insertion of spindle cotton plug or the layered roller gauze, the latex urological Sir Foleys catheter and its fine grade silicone modifications, feeding vessel bipolarization or embolization. The middle turbinate being the line of demarcation between the internal and external carotid supply to the nose. The anterior and posterior ethmoid arteries are the distributaries of the internal carotid system. The former is ligated or fulgurated via the external Howarth or the intranasal endoscopic approach. The sphenopalatine artery is the primary distributary of the external carotid system to the nasal and the paranasal region, which is accessed trans-nasally or trans-antrally and ligated, clipped or fulgurated in uncontrolled epistaxis. Endoscopic visualization facilitates the procedure. The intervention is precise, quick and avoids the uncomfortable sequel of conventional nasal tamponade, like excess nasal crusting, anosmia, cacosmia and cheek paraesthesia.

Certain anatomical variants of the paranasal sinuses (PNS) predispose to injury of surrounding critical structures during functional endoscopic sinus surgery (FESS) and the occurrence of common pathologies like sinusitis. However, they are often not reported in preoperative computed tomography (CT). The CT scan of PNS and head of 360 adults (age > 13years) were retrospectively evaluated for variants of cribriform plate, olfactory fossa, lamina papyracea, uncinate process, sphenoid pneumatization, and anterior ethmoid artery by 4 radiologists with experience of 3 to 6years. The prevalence of each variant was obtained. Chi-squared and independent sample t-tests were used to analyze relationships between variables, with significance set at P < .05. The prevalence of Keros Type 1, Type 2, and Type 3 olfactory fossa was 24.4%, 66.9%, and 8.6%, respectively, in the right side and 20.6%, 69.2%, and 10.3%, respectively, in the left side. Mean depth of right and left olfactory fossa was 4.9 mm (±1.9) and 5.2 mm (± 1.8), respectively. Dehiscence/remote fracture of anterior skull base was observed in 1.9% cases. Dehiscence/remote fracture of lamina papyracea was present in 2.8% cases. Haller cells were observed in 13.9%. Conchal, presellar, incomplete sellar, and complete sellar pattern of pneumatization of sphenoid sinus had prevalences of 2.5%, 6.4%, 26.7%, and 64.4%, respectively. The prevalence of dehiscence of carotid canal in sphenoid sinus was 7.2%. The prevalence of bony septa insertion into carotid canal was 37.8%. The prevalence of supraorbital pneumatization was 51.4%. The prevalence of agger nasi cell and pneumatization of crista galli were 82.2% and 16.7%, respectively. Preoperative CT provides an opportunity to look for critical structures in relation to the PNS. Radiologists should report these findings to prevent potential complications during FESS.

Bridging the gap: A scoping review of endovascular and microsurgical approaches to anterior ethmoidal dural arteriovenous fistulas.

ABSTRACT Context: Although the anterior ethmoidal artery (AEA) is an important landmark in skull base surgery, due to its highly variable position in accordance with the ethmoidal roof, it is very vulnerable to injury during endoscopic sinus surgery (ESS). Aim: Due to the lack of studies emphasizing the necessary anatomical specifications and anomalies that need to be recognized before major surgeries such as ESS, this study aims to reveal anatomical variations of AEA with the hopes of aiding surgeons avoid these complications. Subjects and Methods: This study is a cross-sectional observational multicentered study conducted through a retrospective review of consecutive computed tomography scans of the peripheral nervous system spanning from April 2022 to April 2024. It includes 118 patients with or without AEA canal dehiscence, either partial or complete dehiscence. Results: The average age of the patients was 40.7 years. Among the total 118 patients, 88 (74.6%) patients did not have AEA canal (AEAC) dehiscence but among the 28 cases that did, bilateral AEA canal dehiscence was the most common. Furthermore, a direct correlation was found between many variables such as right and left AEA length, each with their canal dehiscence and each with their relation to the skull base. Conclusions: We conclude that preoperative assessment of the AEA course is crucial to ensuring the safety and effectiveness of paranasal sinus surgery. This is because great variations exist among individuals with regard to their AEAC status.

Using fresh frozen cadaveric rib cartilage graft for nasal septal perforation repair.

Radiological Correlation between the Anterior Ethmoidal Artery and the Supraorbital Ethmoidal Air Cells

Preoperative embolization of anterior skull base meningiomas can facilitate surgical resection by reducing tumor vascularity. However, transophthalmic artery embolization carries risks of visual complications. This study aimed to evaluate the safety and efficacy of this technique by using modern endovascular tools. This retrospective study included patients with anterior skull base meningiomas who underwent preoperative transophthalmic artery embolization followed by surgical resection between January 2022 and April 2024. Patient demographics, tumor characteristics, embolization details, surgical outcomes, and complications were analyzed. Seven patients (median age 57 years; 6 men) underwent embolization for tumors located primarily at the planum sphenoidale (58%). Unilateral embolization was performed in most cases, with 1 bilateral transophthalmic approach. Commonly embolized branches included the anterior and posterior ethmoidal arteries. Polyvinyl alcohol particles were the primary embolic agent (71%). Angiographic devascularization was achieved in all cases without complications. Gross total resection was achieved in 71%, with a median blood loss of 427 mL. At a 9-month follow-up, the median mRS score was 1. With careful patient selection, advanced microcatheter technology, and meticulous technique, preoperative transophthalmic artery embolization can be safely performed to facilitate resection of anterior skull base meningiomas. These results suggest it is a viable option for well-selected patients at experienced centers, though larger prospective studies are needed.

Response to Letter to the Editor on the Manuscript "Posterior Ethmoidal Artery and its Relationship with Anterior Ethmoidal Artery and Skull Base on CT Scan".