Frontal Sinus Drainage Pathway Research Articles

30° anteriorly tilted CT for visualizing the drainage pathway of the frontal sinus.

The optimal tilt for anteriorly tilted coronal CT was examined. A 30° anteriorly tilted coronal CT best visualized the frontal sinus drainage pathway.

30° anteriorly tilted CT for visualizing the drainage pathway of the frontal sinus.

The optimal tilt for anteriorly tilted coronal CT was examined. A 30° anteriorly tilted coronal CT best visualized the frontal sinus drainage pathway.

Exploring the frontal recess: Specimens, endoscopy, and CT perspectives

Abstract The frontal sinus, situated between the external and internal plates of the frontal bone, posterior to the brow ridges, is the most superior and complex structure within the paranasal sinuses. The frontal sinus outflow tract encompasses two parts: the frontal ostium superiorly and the frontal recess inferiorly, collectively forming the frontal sinus drainage pathway. The frontal recess represents the most anterosuperior portion of the ethmoid. Pneumatization of this area can extend from the agger nasi cell anteriorly to the ethmoidal bulla posteriorly. This recess is bounded by the orbital plate of the ethmoid laterally and the middle nasal concha (‘middle turbinate’) medially. The detailed understanding of frontal sinus anatomy is indispensable for medical professionals, including surgeons, otolaryngologists, rhinologists, and radio-logists. The frontal recess is clinically important, especially in the diagnosis and management of various medical conditions, particularly sinusitis. Surgeons often need to navigate this intricate area. Radiological imaging, such as computed tomography (CT) scans, is frequently employed to evaluate the frontal sinus and its drainage pathway, enabling clinicians to identify abnormalities such as tumors, polyps, or foreign bodies. In this study, we investigated the anatomical intricacies of the frontal recess using specimens, CT scans, and endoscopic imagery sourced from didactic and clinical settings.

Anatomy of the Frontal Sinus Drainage Pathway Evaluated in 247 Cadavers to Prevent Cerebrospinal Fluid Leakage After Frontobasal Craniotomy.

The frontal sinus (FS) drainage pathway (FSDP) may be a conduit for cerebrospinal fluid leakage after frontobasal craniotomy. In this cadaveric study, we aimed to evaluate the anatomy of the FSDP. The FSs and FSDPs of 247 cadavers were investigated. We counted the number of FSs and FSDPs in each half-head, verified the presence of a narrowing section in each FSDP, and evaluated the depth, shape, and size of each narrowing FSDP section. We investigated 494 sides and 472 FSDPs of 247 cadavers. FSs were unilaterally undeveloped in 13 of 247 cadavers (5.3%) and bilaterally in 8 (3.2%). FSs were unilaterally duplicated in 7 of 247 cadavers (2.8%), and no FSs were bilaterally duplicated or triplicated. No FSs had 2 or more FSDPs, and all 472 investigated FSDPs were invariably narrowed at various depths. The narrowing FSDP sections were elliptical (78.6%), circular (18.1%), triangular (1.8%), or crescent-shaped (1.4%) and of varying thickness and orientation. Although FSDPs were asymmetric in 92.2% of cadavers and narrowing FSDP sections were located deep (8.9 ± 4.4 mm from the anterior skull base), the narrowing FSDP sections were typically small (area: 5.9 ± 3.3 mm2) or thin (short diameter: 2.1 ± 0.7 mm). Each FS had only one FSDP, all FSDPs were invariably narrowed at various depths, and the narrowing FSDP sections were sufficiently small or thin to allow local closure, facilitating prevention of cerebrospinal fluid leakage after frontobasal craniotomy.

Common Drainage Pathway From Bilateral Frontal Sinuses: Lessons From 2 Cases

Primary pneumatization of the frontal bone occurs in the first year of life, but further pneumatization continues until 18 years of age. Elongation of the ethmoidal infundibulum and frontal recess, or upwards migration of the anterior ethmoidal cells has been proposed as a mechanism of frontal sinus development. The frontal sinus drainage pathway is displaced in the anterior or posterior direction depending on the pneumatization pattern of the frontoethmoidal cells. Also, frontal sinuses can be connected to the infundibulum or directly to the middle meatus depending on the superior attachment pattern of the uncinate process. Bilateral frontal sinuses are separated by their bony septum, and thus have their own drainage pathways. Contrary to this general rule, we experienced two cases of frontal sinuses that were connected to each other, showing a single drainage pathway from both frontal sinuses. We report these two cases along with a literature review.

Pre-FESS Imaging of Paranasal Sinuses and Nasal Cavity: Using Multi-detector Computed Tomography (MDCT) in Understanding Normal Anatomy and Anatomical Variations: Tips and Tricks.

With the advent of Multi-detector Computed Tomography (MDCT), imaging evaluation of paranasal sinuses (PNS) and nasal cavity has witnessed a paradigm shift. Submillimetric slice thickness with superior quality multiplanar reconstructions in orthogonal as well as non-orthogonal planes have resulted in better understanding of the intricate details of complex sino-nasal anatomy and their normal variations. Sagittal plane images have gained increasing acceptance among the sinus surgeons for understanding frontal sinus drainage pathway as well as lateral nasal wall. Analyzing the axial volume dataset in three dimensions has become a routine both for the radiologists as well as sinus surgeon. Besides default window settings, customized window settings enable better appreciation of air containing structures and their boundaries. Mandatory scan check list and template based structured reporting helps the sinus surgeon in better pre-operative planning. Regular mutual interaction between radiologists and sinus surgeon helps better understanding of the surgically relevant anatomy and anatomical variations.

Computed tomography analysis of the anterior ethmoid genu of the frontal recess in non-diseased sinuses.

Knowledge of anatomical variations of the frontal recess and frontal sinus and recognition of endoscopic landmarks are vital for safe and effective endoscopic sinus surgery. This study revisited an anatomical landmark in the frontal recess that could serve as a guide to the frontal sinus. Prevalence of the anterior ethmoid genu, its morphology and its relationship with the frontal sinus drainage pathway was assessed. Computed tomography scans with multiplanar reconstruction were used to study non-diseased sinonasal complexes. The anterior ethmoidal genu was present in all 102 anatomical sides studied, independent of age, gender and race. Its position was within the frontal sinus drainage pathway, and the drainage pathway was medial to it in 98 of 102 cases. The anterior ethmoidal genu sometimes extended laterally and formed a recess bounded by the lamina papyracea laterally, by the uncinate process anteriorly and by the bulla ethmoidalis posteriorly. Distance of the anterior ethmoidal genu to frontal ostia can be determined by the height of the posterior wall of the agger nasi cell rather than its volume or other dimensions. This study confirmed that the anterior ethmoidal genu is a constant anatomical structure positioned within frontal sinus drainage pathway. The description of anterior ethmoidal genu found in this study explained the anatomical connection between the agger nasi cell, uncinate process and bulla ethmoidalis and its structural organisation.

Remote Training of Functional Endoscopic Sinus Surgery With Advanced Manufactured 3D Sinus Models and a Telemedicine System.

Objective: Traditionally, cadaveric courses have been an important tool in surgical education for Functional Endoscopic Sinus Surgery (FESS). The recent COVID-19 pandemic, however, has had a significant global impact on such courses due to its travel restrictions, social distancing regulations, and infection risk. Here, we report the world-first remote (Functional Endoscopic Sinus Surgery) FESS training course between Japan and Australia, utilizing novel 3D-printed sinus models. We examined the feasibility and educational effect of the course conducted entirely remotely with encrypted telemedicine software.Methods: Three otolaryngologists in Hokkaido, Japan, were trained to perform frontal sinus dissections on novel 3D sinus models of increasing difficulty, by two rhinologists located in Adelaide, South Australia. The advanced manufactured sinus models were 3D printed from the Computed tomography (CT) scans of patients with chronic rhinosinusitis. Using Zoom and the Quintree telemedicine platform, the surgeons in Adelaide first lectured the Japanese surgeons on the Building Block Concept for a three Dimensional understanding of the frontal recess. They in real time directly supervised the surgeons as they planned and then performed the frontal sinus dissections. The Japanese surgeons were asked to complete a questionnaire pertaining to their experience and the time taken to perform the frontal dissection was recorded. The course was streamed to over 200 otolaryngologists worldwide.Results: All dissectors completed five frontal sinusotomies. The time to identify the frontal sinus drainage pathway (FSDP) significantly reduced from 1,292 ± 672 to 321 ± 267 s (p = 0.02), despite an increase in the difficulty of the frontal recess anatomy. Image analysis revealed the volume of FSDP was improved (2.36 ± 0.00 to 9.70 ± 1.49 ml, p = 0.014). Questionnaires showed the course's general benefit was 95.47 ± 5.13 in dissectors and 89.24 ± 15.75 in audiences.Conclusion: The combination of telemedicine software, web-conferencing technology, standardized 3D sinus models, and expert supervision, provides excellent training outcomes for surgeons in circumstances when classical surgical workshops cannot be realized.

Association between the insertion type of the uncinate process and the development of Frontal Sinus Mucoceles - is there a relationship?

BackgroundThe frontal sinus drainage pathway is formed by either the ethmoid infundibulum or the middle meatus, which depends on the superior insertion of the uncinate process. According to Landsberg & Friedman the are 6 types of superior uncinate process insertion.The aim of this study is to find an association between the uncinate process insertion type and the development of frontal sinus mucoceles. MethodsFifty sinus CT scans were analysed. Exclusion criteria were previous nasal surgeries, malignancy, polyposis and an insufficient image quality. Superior insertions of the uncinate process were analysed according to the Landsberg & Friedman classification. The results were tabulated and analysed using SPSS 25.0. ResultsThe analysis revealed type 1 insertion in 6% of the CT scans, type 2 in 32%, type 3 in 26%, type 4 in 0%, type 5 in 28% and type 6 in 8%. Despite 44% of the CT scans with frontal sinus mucocele showing a type 2 insertion of the uncinate process, both the Chi-Square test and the Cramer's V test showed no statistical significance (p>.05). Logistic regression also showed that uncinate process insertion type does not influence the likelihood of development of frontal sinuses mucoceles. ConclusionsThe insertion of the uncinate process does not influence the development of frontal sinus mucoceles.

Endoscopic management of frontal sinus CSF leaks

IntroductionEndoscopic management of frontal sinus cerebrospinal fluid leaks has become the gold standard of treatment, with high success rates and low morbidity. The aim of this study is to review our experience in managing this challenging condition. ObjectiveTo review our experience in treating frontal sinus cerebrospinal fluid leaks through an endonasal endoscopic approach. MethodsA retrospective evaluation of patients undergoing endoscopic surgery for frontal sinus cerebrospinal fluid leaks was performed. Demographics, defect location and etiology, surgical and reconstructive technique, complications, and postoperative followup were examined. ResultsTwenty-two patients with a mean age of 40.4 years were treated surgically by the senior author between 2015 and 2019. Cerebrospinal fluid leak was either traumatic (17) or spontaneous (5). Successful first-attempt endoscopic repair was accomplished in all cases. A combined endoscopic-trephination approach was necessary in 5 patients (22.8%). No serious complications were reported, and frontal sinus drainage pathway was patent in all our cases. Revision surgery was necessary in only 2 patients for synechia formation. The mean patient followup was 22.7 months (range: 7 − 41 months). ConclusionProgress in the field of endoscopic surgery has shifted the paradigm, establishing endoscopic repair of frontal sinus leaks as the standard of care. A few remaining limits of this approach could be addressed by combining endoscopy with frontal trephination.

Association between the insertion type of the uncinate process and the development of Frontal Sinus Mucoceles - is there a relationship?

BackgroundThe frontal sinus drainage pathway is formed by either the ethmoid infundibulum or the middle meatus, which depends on the superior insertion of the uncinate process. According to Landsberg & Friedman the are 6 types of superior uncinate process insertion.The aim of this study is to find an association between the uncinate process insertion type and the development of frontal sinus mucoceles. MethodsFifty sinus CT scans were analysed. Exclusion criteria were previous nasal surgeries, malignancy, polyposis and an insufficient image quality. Superior insertions of the uncinate process were analysed according to the Landsberg & Friedman classification. The results were tabulated and analysed using SPSS 25.0. ResultsThe analysis revealed type 1 insertion in 6% of the CT scans, type 2 in 32%, type 3 in 26%, type 4 in 0%, type 5 in 28% and type 6 in 8%. Despite 44% of the CT scans with frontal sinus mucocele showing a type 2 insertion of the uncinate process, both the Chi-Square test and the Cramer's V test showed no statistical significance (p>.05). Logistic regression also showed that uncinate process insertion type does not influence the likelihood of development of frontal sinuses mucoceles. ConclusionsThe insertion of the uncinate process does not influence the development of frontal sinus mucoceles.

Frontal Sinus Preservation During Cerebrospinal Fluid Leak Repair.

To validate the repair of frontal sinus cerebrospinal fluid (CSF) leaks with preservation of frontal sinus drainage pathway (FSDP), independently of the approach used, and to establish the indications and limits of the endoscopic approach. A retrospective evaluation of patients undergoing surgery for frontal sinus CSF leaks was performed. Demographics, indications for both endoscopic/combined endoscopic and open approaches, complications, methods for maintaining FSDP, and perioperative outcomes were examined. Fifty-three patients (average age 45 years) with frontal sinus CSF leaks were treated surgically from 2000 to 2018. All CSF leak repairs were successful at the 1st attempt with a mean follow-up of 76.8 months (range 4-227 months). Etiology was spontaneous (14), traumatic (26), and iatrogenic (13). In 17 patients, a purely endoscopic approach was performed, while an endoscopic endonasal orbital transposition procedure was added in 4 out of this group. In 23 patients, a combined endoscopic and osteoplastic procedure was employed, while in 13 patients a combined craniotomy and endoscopic procedure was performed. All frontal sinuses remained patent except for 2 cranialization patients. With contemporary endoscopic instrumentation and techniques, endoscopic closure of frontal sinus CSF leaks even in the far superolateral wall is feasible in selected patients. However, the surgeon should consider the option of combining an external approach when required. Preserving the FSDP should be the main aim regardless of the approach.

Three-dimensional computed tomography analysis of frontoethmoidal cells: A critical evaluation of the International Frontal Sinus Anatomy Classification (IFAC).

Two major classifications of frontoethmoidal cells, Lee and Kuhn and the IFAC (International Frontal Sinus Anatomy Classification), distinguish anterior, posterior and medial cells. The European anatomical position paper includes also lateral cells. According to the IFAC, anterior cells push the frontal sinus drainage pathway (FSDP) medially, posteriorly or posteromedially. Posterior cells push the FSDP anteriorly. The only medial cell, pushing the FSDP laterally is the frontal septal cell, which is attached to or located in the interfrontal sinus septum. The aim of this study was to verify the IFAC and characterise cells, which are inconsistent with this classification. A radioanatomic analysis. Tertiary university hospital. One hundred and three Caucasian adult patients with no inflammatory changes in paranasal sinuses CT. Results of assessment of multiplanar reconstruction of thin slice CT. Two types of cells that cannot be classified using the IFAC were found: (a) Lateral cells extending between the skull base and the anterior buttress, pushing the FSDP anteromedially or medially, present in 34 (16.5%) of the sides, (b) Paramedian cells: medially based, not adjacent to the interfrontal septum, pushing the FSDP laterally and posteriorly, present in 33 (16%) of sides. Suprabulla cells and suprabulla frontal cells were found to push the FSDP in directions other than anterior 28% and 31% of the time respectively. Neglecting lateral and paramedian cells may lead to inconsistent results between radioanatomical studies and impede communication between surgeons. They should be included in existing classifications of frontoethmoidal cells.

Anatomical Variation in the Drainage Pattern of Frontal Sinus – A Cadaveric Study

Abstract Background A proper and detailed knowledge about the frontal sinus drainage pathway is essential for the radiologist to interpret the computed tomography scan of the paranasal air sinuses to find out normal and variant in the anatomy of frontal sinus ostium, and also for the surgeons to do endonasal sinus surgery particularly in the frontal sinus area with enough confidence and to give good postoperative result. With this background, the present study was focused to study the variation in the drainage pattern of frontal sinus in relation to uncinate process in cadaveric specimens. Materials and Methods The midsagittal section of head and neck portion of 40 cadaveric specimens with intact frontal sinus and frontal sinus drainage pattern were selected. By careful dissection, pattern of frontal sinus drainage was identified and pattern of drainage of frontal sinus in relation with uncinate process was studied. Result Frontal sinus drainage pattern is anteromedial to uncinate process (Type 1) in 28 specimens (70%) and posterolateral to uncinate process (Type 2) in 12 specimens (30%). Conclusion The results of our study show that the frontal sinus drainage pattern is more commonly present anteromedial to uncinate process compared with posterolateral position. This variation in the drainage pattern of frontal sinus should be kept in mind by the radiologist to give proper radiological interpretation and by the surgeons to avoid intraoperative complications and also to give good postoperative result.

The Anterior Ethmoidal "Genu": A Newly Appreciated Anatomic Landmark for Endoscopic Sinus Surgery.

Human sinonasal anatomy varies widely between patients, challenging surgeons operating in the sinuses. Ethmoid sinus anatomy is so variable it has been referred to as a labyrinth. Accordingly, reliable, consistent anatomic landmarks aid surgeons operating in this region. The goal of this investigation was to explore our observations and hypothesis that the ethmoidal bulla and the uncinate process are not entirely separate structures but rather attach, and the attachment could potentially provide a landmark for surgeons performing ethmoid and frontal recess surgery. Ethmoid sinus anatomy was studied in 57 sinonasal complexes through a variety of methods including gross anatomic dissection, endoscopic dissection and 3D CT stereoscopic imaging. The uncinate process and ethmoidal bulla were noted to fuse at the superior aspect of the hiatus semilunaris in 57/57 cases, forming a genu-like feature in the anterior ethmoid. This consistent anatomic feature related closely to the frontal sinus drainage pathway, which drained medial to it in 44/57 (77%) cases. The anterior ethmoidal "genu" appears to be an excellent anatomic feature that surgeons can use during ethmoid and frontal recess surgery. High resolution 3D stereoscopic CT scan is capable of demonstrating sinonasal anatomy in a detailed fashion previously only achieved by cadaveric dissection. This technology can potentially allow for a virtual dissection of a patient's anatomy prior to surgery and could improve minimally invasive procedures and reduce complications. Clin. Anat. 32:534-540, 2019. © 2019 Wiley Periodicals, Inc.

Synedra, a free digital imaging viewer, is relevant in assessment of frontal sinus drainage pathway

Objective The aim was to evaluate the most relevant free radiological digital imaging and communications in medicine (DICOM) software in analysis of air cells related to the frontal sinus drainage pathway (FSDP). Background DICOM is the leading standard for computed tomography (CT) scan image data management in different paranasal sinuses and rhinology practice. Patients and methods In the present prospective randomized case-series study of 51 patients scheduled for CT scan for nose and paranasal sinuses, six DICOM image viewers (Onis, Synerdra, 3D-Slicer, InVesalius, RadiAnt, and Philips) were compared by two expert head and neck radiologists for analysis of CT FSDP anatomy using modified Bent–Kuhn classification, which presents a total score for 10 commonly used radiological parameters. Each was scored from 0 to 10, and a total score and mean were calculated. Results Synedra software had the highest total mean scores (64.5/100) followed by RadiAnt (45/100), 3D-slicer (29.5/100), Onis (16/100), and Invesalius (15/100), with the least being Philips (14.5/100). Conclusion Synedra could be a relevant free DICOM viewer for analysis of air cells related to the FSDP.

Teaching Residents Frontal Sinus Anatomy Using a Novel 3-Dimensional Conceptualization Planning Software-Based Module.

The Frontal Sinus Masterclass (FSMC) is an effective method for teaching frontal sinus anatomy. A third party developed new software using the same 3-dimensional building block concept. The authors sought to determine whether the use of the software for the educational module yielded similar results to the original FSMC, which used wooden blocks. The study was performed at a sinus course for residents. A precourse test assessed the ability to decipher frontal sinus anatomy prior to the course. Computed tomography (CT) scans of the sinuses were evaluated in triplanar view, and participants attempted to reconstruct the anatomy using the new software. Subsequently, the course instructor explained the anatomy and showed a short corresponding surgical video of the frontal sinusotomy. Cases progressed in anatomical difficulty and inflammatory load. A postcourse test determined knowledge after the course. In sum, 50 residents completed the pre- and postcourse tests. Overall scores increased from 60.5% to 65.2% ( P = .004). Subanalysis also demonstrated improved ability to locate the frontal drainage pathway from 32.5% to 46% ( P = .011) and label the frontal recess cell structures from 64% to 67.6% ( P = .045). There is minimal literature on proven methods for teaching frontal sinus anatomy. Objectively, participants of the modified FSMC simulation training using new software improved their ability to recognize cells of the frontal recess on CT scans. They especially exhibited better localization of the frontal sinus drainage pathway. Subjectively, participants reported benefit from the course and felt they would be better surgeons.

Anatomical terminology of the internal nose and paranasal sinuses: cross-cultural adaptation to Portuguese.

IntroductionFunctional endonasal endoscopic surgery is a frequent surgical procedure among otorhinolaryngologists. In 2014, the European Society of Rhinology published the “European Position Paper on the Anatomical Terminology of the Internal Nose and Paranasal Sinuses”, aiming to unify the terms in the English language. We do not yet have a unified terminology in the Portuguese language.ObjectiveTranscultural adaptation of the anatomical terms of the nose and paranasal cavities of the “European Anatomical Terminology of the Internal Nose and Paranasal Sinuses” to Portuguese.MethodsA group of rhinologists from diverse parts of Brazil, all experienced in endoscopic endonasal surgery, was invited to participate in the creation of this position paper on the anatomical terms of the nose and paranasal sinuses in the Portuguese language according to the methodology adapted from that previously described by Rudmik and Smith.ResultsThe results of this document were generated based on the agreement of the majority of the participants according to the most popular suggestions among the rhinologists. A cross-cultural adaptation of the sinonasal anatomical terminology was consolidated. We suggest the terms “inferior turbinate”, “nasal septum”, “(bone/cartilaginous) part of the nasal septum”, “(middle/inferior) nasal meatus”, “frontal sinus drainage pathway”, “frontal recess” and “uncinate process” be standardized.ConclusionWe have consolidated a Portuguese version of the European Anatomical Terminology of the Internal Nose and Paranasal Sinuses, which will help in the publication of technical announcements, scientific publications and the teaching of the internal anatomical terms of the nose and paranasal sinuses in Brazil.

Anatomical relations between the frontal sinus drainage pathway and the agger nasi cell

Anatomical relations between the frontal sinus drainage pathway and the agger nasi cell

The application of 3D reconstruction in investigating the frontal sinus drainage pathway based on computer tomography data

Objective:The aim of this study is to explore the value of 3D reconstruction technology based on computer tomography data in understanding the frontal sinus drainage pathway. Method:Three-dimensional reconstruction of DICOM data from 100 cases of sinus CT was performed by using Mimics 19.0 software. The 3D models were used to study types, the relative locations of frontal sinus and recess cells as well as the influence of the frontal sinus drainage pathway. Result:The 3D model of frontal sinus, frontal recess cells and frontal sinus drainage pathway were reconstructed successfully. Among them, the incidence of nasal cavity was 95.5% (191/200), nasal cavity was 31.5% (63/200), nasal cavity on the frontal air room was 24.5% (49/200) supra bulla cells were 54% (108/200), supra bulla frontal cells were 14.5% (29/200), supraorbital ethmoid cells were 20.5% (41/200), and the rate of frontal septal cells were 4% (8/200). It visually demonstrated the relationship between the frontal recess and the frontal sinus drainage channel. Conclusion:The 3D reconstruction technology based on computer tomography data not only helps us to understand the anatomy of the frontal sinus, the relative position of the frontal crypt and the effect on the frontal sinus drainage channel, but also provides a new method for preoperative planning and intraoperative guidance to endoscopic frontal sinus surgery.