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.

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.

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.

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.

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.

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.

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.

Comparing Endoscopic Measurements of the Anterior and Posterior Ethmoidal Arteries with CT Measurements: A Cadaveric Study.

OBJECTIVE: To reveal the reliability of radiological measurements of the ethmoid arteries. METHOD: Five fresh frozen cadaveric heads underwent computed tomography and endoscopic sinus surgery. The lateromedial length of the anterior ethmoidal artery (AEA) and its distance to the axilla of the middle turbinate (MTA), the sphenoethmoidal recess (SR) and the posterior ethmoidal artery were measured. The posterior ethmoidal artery (PEA) was referenced to the SR. These anatomical parameters were measured both radiologically and endoscopically, and the compatibility of the two was examined. RESULTS: Ten nasal cavities were dissected. We found that the distance of MTA to the AEA was 16±8 mm in dissection, 21±4 mm radiologically in the sagittal section, the distance of SR to the AEA was 14±3 mm in dissection, 19±4 mm radiologically in the sagittal section, and the distance of the AEA to the PEA was 10±3 mm in dissection, 12±3 mm radiologically in the axial section. The distance of the PEA to SR was 6±3 mm in dissection, 8±2 mm radiologically in the sagittal section. CONCLUSIONS: The distance of the AEA to the MTA, the distance of the AEA to the PEA and the distance of the PEA to the SR were compatible with each other in the dissection and in the radiologically evaluation, whereas the distance of the AEA to the SR was not compatible.

Maxillary ostium preservation in ethmoidectomy.

The paranasal sinuses play a role in producing and storing nitric oxide (NO). NO is a powerful antiviral and antibacterial gas which may be involved in the non-specific immune defenses of the respiratory tract. Conducted by the inspiratory current at the alveolar-capillary membrane, it increases pulmonary venous blood oxygenation. NO is actively released in the form of independent boluses in the respiratory tract, thanks to a sphincter function that can be identified during ethmoidectomy under general anesthesia. Safeguarding paranasal sinus physiology necessarily involves conserving this ostial sphincter function, which is essential to the respiratory role of the paranasal sinuses. Although it has not yet been demonstrated that the destruction of this ostial function has measurable consequences for respiratory function, it makes sense to avoid systematic antrostomy and to preserve this ostial function whenever possible, depending on the clinical conditions. This technical note describes step-by-step how to conserve the maxillary ostium, in the example of radical ethmoidectomy with mucosal ablation for nasal polyposis (nasalization). It is illustrated by two videos. The discussion focuses on the respective indications for ostial preservation and middle meatotomy (antrostomy).

Resection of Orbital Myxoma With Magnetic Resonance Imaging Evidence of Ethmoid Sinus Origin: Case Report and Review of 20 Patients in the Literature.

A 41-year-old woman showed a palpable mass at the superonasal orbital edge on the right side. Magnetic resonance imaging demonstrated a lobulated fluid-containing tubular mass which extended anteriorly to posteriorly along the medial orbital wall, nasal to the eyeball. She was followed once a year for 8 years until the age of 49 years when she decided to undergo surgical resection because of the enlarged mass. The lobulated large mass was resected and the pathology showed sparsely distributed spindle cells, positive for CD34, in alcian blue-positive mucous substances, indicative of myxoma. Postoperative magnetic resonance imaging showed residual lobulated tubular mass along the optic nerve on the medial side and superior to the eyeball. The residual orbital mass showed stable structure with more evident connection with the ethmoid sinus lesion, suggestive of the ethmoid origin, in 12 years until the age of 61 years. In the review of 20 patients with orbital myxomas in the literature, in addition to this case, roughly classified locations in the orbit were retrobulbar in 8 patients, on the lateral side of the orbit in 4, on the superior side in 6, on the medial side in 1 (this patient), and in the orbit with no specific description in 2. In pathological examinations, immunohistochemistry was not done in 8 patients, done but all negative in 2, and positive in 11 patients: nerve sheath myxoma was diagnosed in 3 patients based on positive S100 staining. Orbital myxoma is rare but considered in differential diagnosis of orbital masses.

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

PURPOSE: Understanding the anatomy of the paranasal sinuses and their variations is essential to achieving safe and effective endoscopic sinus surgery. The ethmomaxillary sinus (EMS) is a relatively under-researched anatomical variation. This study investigated the prevalence, clinical features, and effect of EMS on the maxillary sinus in comparison with Haller's cells. METHODS: Patients who visited the Rhinology Clinic at our hospital for rhinologic symptoms between January 2020 and December 2020. Computed tomography (CT) scans of paranasal sinuses were obtained at 1 mm-section thickness. Using CT scans, we investigated the clinical features of EMS, measured maxillary sinus volume, and analyzed the presence of maxillary sinusitis. RESULTS: EMS was observed in 26 of the 250 patients (10.4%). The male-to-female ratio was equal. The age ranged from 18 to 83 years (mean age, 56.3). Of the patients with EMS, 65.4% were unilateral and 34.6% were bilateral. The prevalence of Haller's cells was similar to that in EMS (10.8%). In the analysis of patients with unilateral EMS, the EMS side was found to have a significantly reduced maxillary sinus volume compared to the opposite side, whereas the difference was not significant in Haller's cells. There was no significant relationship between EMS or Haller's cells and maxillary sinusitis. CONCLUSIONS: EMS can significantly affect maxillary sinus volume. Therefore, surgeons should thoroughly review PNS CT scans before paranasal sinus surgery to determine the presence and features of EMS.

Osteoma of the ethmoid sinus in a pediatric patient - a case report.

BACKGROUND: Osteomas of the paranasal sinuses occur rarely in the pediatric population, we find only a few reference of symptomatic osteomas in the literature. Opinions on the indication for surgical treatment are controversial. CASE: The authors present a case of symptomatic osteoma of the right ethoimoidal sinus in a 12-year-old boy, who was treated surgically, with endoscopic endonasal approach. The symptomatology, diagnosis and therapy of these tumors in the pediatric patient are discussed. CONCLUSION: Osteomas of the paranasal sinuses are slow-growing benign lesions. Symptomatic osteomas can grow expansively and cause serious complications. The treatment of osteoma is surgical and the endoscopic approach offers the possibility of removal with cosmetic benefits.

[Efficacy of glucocorticoid stent implantation in ethmoid sinus after endoscopic sinus surgery for chronic rhinosinusitis with nasal polyps].

Objective:To evaluate the efficacy of glucocorticoid sinus stents implanted 2 weeks after functional endoscopic sinus surgery（FESS） for the treatment of chronic rhinosinusitis with nasal polyps（CRSwNP）. Methods:CRSwNP patients with similar bilateral lesions were randomly divided into two groups, with a stent group of 25 patients and a control group of 24 patients. Patients in the stent group had glucocorticoid sinus stents implanted into the bilateral ethmoid sinuses 2 weeks after FESS, while the control group underwent postoperative debridement only. Follow-up assessments occurred at postoperative weeks 2, 4, 8, and 12. Patients were asked to assess their sensation of nasal symptoms using a 10-point visual analog scale. Efficacy was assessed by endoscopic evaluations. Sinus obstruction, crusting/coagulation, polyp formation, middle turbinate position, adhesions, mucosa epithelialization, and postoperative intervention were assessed as efficacy outcomes. GraphPad Prism 9 was applied for statistical analysis. Results:At 4 and 8 weeks postoperatively, the stent group showed significant improvement in VAS scores of nasal congestion and runny nose compared with the control group（P<0.05）. No significant difference was observed in the VAS scores of head and facial stuffiness, loss of smell, or nasal dryness/crusting between the two groups（P>0.05）. Compared with the control group, the stent group had a lower rate of polypoid formation at 4, 8, and 12 weeks postoperatively. At postoperative week 12, the rate of mucosal epithelialization in the ethmoid cavity was significantly higher in the stent group. During the follow-up, the frequency of postoperative intervention was significantly lower in the stent group than in the control group（P<0.05）. Besides, a lower incidence of middle turbinate lateralization was found in the stent group at 8 and 12 weeks postoperatively. At 8 weeks postoperatively, the stent group had a percentage of adhesion lower than that of the control group（all P<0.05）. Conclusion:Implantation of glucocorticoid sinus stents after FESS can maintain sinus cavity patency, improve the inflammatory status of the operative cavity, reduce postoperative interventions, and promote benign regression of the operative cavity.

A low-cost prosthetic orbital simulation model for endoscopic anterior ethmoid artery ligation.

OBJECTIVE: This study aimed to develop and evaluate a low-cost orbital prosthesis for simulation of endoscopically assisted intra-orbital anterior ethmoidal artery ligation. METHODS: A low-cost orbital prosthesis was built and evaluated by ENT surgical trainees. Feedback was given following the assessment in the form of a face validity questionnaire. RESULTS: Results were scored on a Likert scale of 1-7 (low to high). Trainees had limited exposure to the procedure (40 per cent) and predominantly low levels of confidence (mean, 3.67) that correlated with a lack of first-hand experience. The anatomy and likeness to human tissue of the prosthesis were both ranked highly, with mean scores of 5.0 and 4.93, respectively. CONCLUSION: The results of this study support the idea that a simple anatomical prosthesis for the simulation of endoscopic anterior ethmoidal artery ligation can be created with potential value to otolaryngology surgical training. To the authors' knowledge, this is the first documentation of simulated surgical epistaxis management using an artificial anatomical model.

Anatomical landmarks for localisation of the anterior ethmoidal artery: a combined radiological and cadaveric (endoscopic) study.

PURPOSE: The anterior ethmoidal artery is a major surgical landmark that is susceptible to iatrogenic injury during surgery of the anterior ethmoidal sinus, frontal sinus, and skull base. The present study aimed to define the location of the anterior ethmoidal artery in relation to specific anatomical landmarks using radiological imaging and endoscopic dissection. METHODS: Eighty-six anterior ethmoidal arteries were assessed using computed tomography scans (bilateral analyses) and forty anterior ethmoidal arteries were assessed using cadaveric specimens (bilateral analyses). The skull base, anterior nasal spine, anterior axilla of the middle turbinate, and nasal axilla were morphometrically analysed to determine their reliability as anterior ethmoidal artery landmarks. RESULTS: Distances to the skull base, anterior nasal spine, and nasal axilla displayed statistically significant differences between sexes and sides (p < 0.05). All landmarks demonstrated excellent reliability as anatomical landmarks for the localisation of the anterior ethmoidal artery, radiologically and endoscopically (ICC values ranged from 0.94 to 0.99). CONCLUSION: The middle turbinate axilla was the most reliable landmark, due to the lack of statistically significant differences according to sex and laterality, and the high inter-rater agreement between measurements. Anatomical knowledge of variations and relationships observed in the present study can be applied to surgeries of the anterior ethmoidal sinus, frontal sinus, and skull base to improve localisation of the anterior ethmoidal artery, preoperatively and intraoperatively, and avoid iatrogenic injury of the vessel.

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

OBJECTIVES: We investigated supraorbital ethmoid cell (SOEC) presence and types in paranasal sinus computed tomography (PNSCT). METHODS: The PNSCT images of 188 adult patients (93 males and 95 females) were evaluated as SOEC group (n = 87 sides), and non-SOEC group (n = 289 sides, control). In both groups, anterior ethmoid artery (AEA) notch-ethmoid roof distance and presence of AEA canal were evaluated. In the SOEC group, SOEC types (type 1 to 3) and SOEC angle are also examined. RESULTS: SOEC was detected in 87 sides (23.13 %). SOEC type 2 was the most detected type (71.3 %). AEA notch-ethmoid roof distance of the SOEC group was significantly higher than those in the non-SOEC group. AEA notch-ethmoid roof distance of the SOEC Type 3 group was significantly higher than SOEC Type 2 group. AEA notch-ethmoid roof distance was 3.74 ± 1.81 mm in the SOEC group and 0.68 ± 1.16 mm in the non-SOEC group. When SOEC types were considered, this distance was 5.29 ± 2.66 mm in type 3, 3.35 ± 1.35 mm in type 2 and 3.48 ± 0.92 mm in type 1. In higher SOEC types, SOEC angle; and AEA notch-ethmoid roof distance increased. CONCLUSION: In more pneumatized SOEC presence, SOEC angle increase, and AEA notch-ethmoid roof distance increases, AEA runs inferiorly in the ethmoid cells and freely below the skull base; and is more susceptible to injury. The surgeons should be more careful not to damage AEA in the FESS when detecting well-pneumatized SOECs (SOEC Type 3).

Osteoradionecrosis of the lamina papyracea leading to recurrent orbital infections-A case study.

Osteoradionecrosis (ORN) is a well-known complication of radiotherapy (RT) to the sino-nasal cavity and nasopharynx. Here, we report a case of recurrent orbital infections secondary to ORN of the lamina papyracea (LP). A 66-year-old female presented to our unit with right periorbital swelling and pain after having undergone chemotherapy and proton beam irradiation to her ethmoid sinuses for sino-nasal undifferentiated carcinoma (SNUC) 5 years prior. She had also undergone endoscopic sinus surgery for chronic rhinosinusitis about a year prior to the current presentation. Her post-operative course was notable for recurrent episodes of pre-septal cellulitis occurring about 3 months apart that were increasingly severe. Examination revealed right proptosis, and endoscopy showed an exposed and denuded LP with scant crusting of the ethmoid sinuses. Microbial studies did not yield any significant growth, and imaging showed enhancement of the right orbit. The working diagnosis was acute right orbital cellulitis secondary to ORN of the right LP. She was treated with broad spectrum intravenous antibiotics and systemic steroids, but experienced minimal symptomatic improvement. She then underwent endoscopic resection of the right LP, and histopathological examination showed osteonecrosis on an inflammatory background. Post-operatively, all orbital symptoms resolved and she was well at 6 months' follow up. In the discussion, we highlight additional factors in our patient that may have contributed to this clinical presentation, and hope that this report raises awareness of a rare complication of RT to the sino-nasal cavity.

Radiological relationship of the ethmoid slit with the frontal sinus and the anterior ethmoidal artery and applications to the frontal sinus drillout.

PURPOSE: To compare two types of CT acquisition parameters: CT scan of the facial bone and CT scan of the sinuses, for studying the ethmoidal slit and its relationship with the frontal sinus and anterior ethmoidal artery. MATERIALS AND METHODS: Retrospective study of 145 scans of the sinuses and 79 of the facial bones performed between 2012 and 2016. On each scan, the visibility of the ethmoidal slits, their length, their distance from the ethmoidal artery, and their relationship with the anterior and posterior wall of the frontal sinus were studied. RESULTS: The ethmoidal slit was better visualized on CT scans of the facial bone (58.2%) than on those of the sinuses (43.1%) (p = 0.02). The distance between the anterior ethmoidal artery and the anterior part of the cribriform plate was 9.3 mm for CT scans of the facial bone and 8.4 mm for CT scans of the sinuses. The theoretical risk of damaging the glabellar soft tissue and that of damaging the meninges during a frontal sinusotomy was evaluated, respectively, at 9.6% and 26.1% for CT scans of the facial bone, and at 6.2% and 21.5% for sinus scans. CONCLUSIONS: CT scans of the facial bone are better than CT scans of the sinuses for identifying ethmoidal slits and their distance from the canal of the anterior ethmoidal artery. The identification of these elements is relevant for the surgeon during frontal sinus surgery and makes it possible to assess the risk of damaging the glabellar soft tissue or meninges. Performing a CT scan of the facial bone seems preferable to that of a CT scan of the sinuses in certain pathological situations, such as cerebrospinal rhinorrhea or revision surgeries of the frontal sinus.

Anterior ethmoid and frontal sinus drainage pathways: five patterns formed and defined by their bony walls.

PURPOSE: To perform endoscopic sinus surgery safely and effectively, surgeons need to visualize the complex anatomy of the anterior ethmoid and frontal sinus region. Because this anatomy is so variable and individualized, the foundation of understanding lies in identifying, following, and visualizing the drainage pathway patterns and anticipating possible variations. METHODS: We studied 100 sides (50 cases: 22 male, 28 female, aged 12-86, average age 46.5 years, ± 19.5) using computed tomography (CT) and multiplanar reconstruction (MPR) to identify and classify the drainage pathways leading to the frontal sinus and anterior ethmoidal cells. RESULTS: Analysis revealed five patterns of drainage pathways defined by their bony walls: between the uncinate process and the lamina papyracea [UP-LP]; between the uncinate process and the middle turbinate [UP-MT]; between the uncinate process and the accessory uncinate process [UP-UPa]; between the uncinate process and the basal lamella of the ethmoidal bulla [UP-BLEB]; and between the basal lamella of the ethmoidal bulla and the basal lamella of the middle turbinate [BLEB-BLMT]. In most cases, BLEB formed the posterior wall of the drainage pathway of the frontal sinus, indicating BLEB could be one of the most important landmarks for approaching the frontal sinus. CONCLUSIONS: As endoscopic sinus surgery depends on an understanding of this anatomy, this study may help surgeons to identify and follow the drainage pathways more accurately and safely through the anterior ethmoid to the frontal sinus.