What is the rate of occult nodal metastasis in squamous cell carcinomas of the sinonasal tract? A systematic review.

OBJECTIVE: The role of elective neck dissection (END) in the management of clinical N0 (cN0) squamous cell carcinomas (SCC) of the sinonasal tract is unclear. In this systematic review, we evaluate the risk of occult nodal metastasis in sinonasal SCCs with cN0M0 tumors to support clinical decision making. METHODS: A literature search was conducted in the following three electronic databases: Medline/PubMed, ScienceDirect, and Google Scholar. Articles were assessed for eligibility in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Two independent authors extracted the data. The Methodological Items for Non-Randomized Studies (MINORS) tool was used for the assessment of biases of each included study. RESULTS: Our systematic review included six studies that met the inclusion criteria, all retrospective in design. The rate of histologically proven metastasis of sinonasal SCC to the clinically negative neck is 12.5%. Almost half of the positive cases are pathologically staged as N2 (6.5%). CONCLUSION: Our systematic review provides the rate of sinonasal SCC occult metastasis to the neck so that the surgeons can discuss with patients the risks and possible merits of adding an elective neck management in the surgical plan.

Benign bony lesions of paranasal sinuses and skull base: from osteoma to fibrous dysplasia.

PURPOSE OF REVIEW: Benign bony lesions of the craniofacial complex are relatively common. However, their location close to critical neurovascular structures may render their treatment, if required, highly challenging.This article reviews the current literature on their pathophysiology, diagnosis, natural course and treatment, with a focus on most recent findings. RECENT FINDINGS: A new classification has been suggested concerning endoscopic resectability. The ratio of lateral frontal to interorbital distance can accurately and reliably predict the endoscopic reach to lateral frontal sinus, while orbital transposition can assist us in reaching lateral frontal sinus when anatomy is unfavorable. New and combined endoscopic transnasal and transorbital approaches are now in the surgical armamentarium. Prophylactic optic nerve decompression in fibrous dysplasia is absolutely contraindicated as it leads to worse visual outcomes. Radiotherapy of such lesions is of no benefit and may lead to a higher risk of malignant transformation. The presence of Guanine Nucleotide binding protein Alpha Stimulating (GNAS) mutation in chromosome 20 is universally present in fibrous dysplasia and can differentiate them from ossifying fibromas. SUMMARY: Diagnosis and therapeutic management of benign craniofacial bone lesions remains challenging. If surgical treatment is contemplated, the morbidity of the intervention should always be weighed against the potential benefits. Evolution of extended endoscopic endonasal and transorbital surgery means that more lesions can be reached purely endoscopically with better oncological and cosmetic results.

Gender, age and location-related factors in academic otolaryngology - the Greek paradigm.

OBJECTIVE: To map Greek academic otolaryngologists, and assess gender, age and location-related differences in their rank and academic productivity. METHODS: A pre-established database of local and diaspora scientists was used, after adjustment and updating for otolaryngology. The following data were recorded: age, gender, academic rank, country of work, total citations and h-index of December 2022. RESULTS: A total of 276 Greek academic otolaryngologists were identified in the Scopus database. Of Greek otolaryngologists, 15.9 per cent are women. Of all academic otolaryngologists, 27.1 per cent have a university post, but only 4 per cent of them are women. There is an almost linear correlation between university post ranking and citations. Otolaryngologists based in Greece accounted for 3 out of the 10 most cited Greek otolaryngologists. CONCLUSION: There are significant age, gender and location-related differences in academic output. The representation of women and the full use of their potential in medicine require proactive measures, to lift the burdens limiting their participation.

Posterior epistaxis management: review of the literature and proposed guidelines of the hellenic rhinological-facial plastic surgery society.

PURPOSE: Posterior epistaxis is a common emergency in ENT practice varying in severity and treatment. Many management guidelines have been proposed, all of which are a product of retrospective analyses due to the nature of this pathology, as large-scale double-blind studies are impossible-even unethical-to conduct. The purpose of this review is to perform a thorough analysis and comparison of every treatment plan available and establish guidelines for the best possible outcome in accordance to every parameter studied. Given the extensive heterogeneity of information and the multitude of studies on this topic, along with the comparison of various treatment options, we opted for a literature review as our research approach. METHODS: A review of the literature was performed using PubMed Database and search terms included "posterior epistaxis", "treatment", "management", "guidelines", "algorithm" "nasal packing", "posterior packing", "surgery", "SPA ligation", "embolization", "risk factors" or a combination of the above. RESULTS: Initial patients' assessment invariably results in most cases in posterior packing. There seems to be a superiority in recent literature of early surgery over nasal packing as a definitive treatment. Embolization is usually used after surgery failure, except for specific occasions. CONCLUSION: Despite the vast heterogeneity of information, there seems to be a need for re-evaluation of the well-established treatment plans according to more recent studies. Suggested treatment algorithm for posterior epistaxis. ABC Airway-Breathing-Circulation, ECA external carotid artery, AEA anterior ethmoidal artery, BT blood transfusion, FA facial artery, HB haemoglobin, IMA internal maxillary artery, SPA sphenopalatine artery.

Primary Intracranial Adenoid Cystic Carcinoma: Report of Three Cases.

Objective Nasal cavity and paranasal sinuses host a variety of malignant tumors with adenoid cystic carcinoma (ACC) being the most frequent cancer of salivary gland origin. The histological origin of such tumors virtually precludes primarily intracranial localization. The aim of this study is to report cases of primarily intracranial ACC without evidence of other primary lesions at the end of an exhaustive diagnostic workup. Methods An electronic medical record search complemented by manual searching was conducted to identify prospective and retrospective cases of intracranial ACCs treated in Endoscopic Skull Base Centre Athens at the Hygeia Hospital, Athens from 2010 until 2021 with a mean follow-up time of at least 3 years. Patients were included if after complete diagnostic workup there was no evidence of a nasal or paranasal sinus primary lesion and extension of the ACC. All patients were treated with a combination of endoscopic surgeries performed by the senior author followed by radiotherapy (RT) and/or chemotherapy. Results Three unique illustrative cases (ACC involving the clivus, cavernous sinus and pterygopalatine fossa, one orbital ACC with pterygopalatine fossa and cavernous sinus involvement and one involving cavernous sinus, and Meckel's cave with extension to the foramen rotundum) were identified. All patients underwent subsequently proton or carbon-ion beam radiation therapy. Conclusions Primary intracranial ACCs constitute an extremely rare clinical entity with atypical presentation, challenging diagnostic workup and management. The design of an international web-based database with a detailed report of these tumors would be extremely helpful.

Endoscopic-assisted transorbital surgery: Where do we stand on the scott's parabola? personal considerations after a 10-year experience.

Transorbital approaches are genuinely versatile surgical routes which show interesting potentials in skull base surgery. Given their "new" trajectory, they can be a very useful adjunct to traditional routes, even being a valid alternative to them in some cases, and add valuable opportunities in selected patients. Indications are constantly expanding, and currently include selected intraorbital, skull base and even intra-axial lesions, both benign and malignant. Given their relatively recent development and thus unfamiliarity among the skull base community, achieving adequate proficiency needs not only a personalized training and knowledge but also, above all, an adequate case volume and a dedicated setting. Current, but mostly future, applications should be selected by genetic, omics and biological features and applied in the context of a truly multidisciplinary environment.

Defining the limits and indications of the Draf III endoscopic approach to the lateral frontal sinus and maximizing visualization and maneuverability: a cadaveric and radiological study.

PURPOSE: The DRAF III procedure has been used for access to the lateralmost part of the frontal sinus. We sought to identify anatomical and radiological measurements as well as modifications that predict the lateral limits of visualization and surgical access after this procedure. METHODS: Seven cadaver heads were imaged with computed tomography scan. The distance from midline to the medial orbital wall (MOWD), midline to the lateral end of the frontal sinus (MLD), the sum of MLDs (SMLD), interorbital distance (IOD) and the shortest anteroposterior distance of the frontal recess (APD) were utilized. The ratios MLD/MOWD, and SMLD/IOD were calculated. The same distances were measured on 41 CT scans. Orbital transposition (OT) and partial resection of the piriform aperture (PAR) were performed; the visualization and reach were assessed. The angle of insertion was measured before and after the modifications. RESULTS: Only the ratio MLD/MOWD was consistently predictive of access to the lateral, superior and posterior wall of the frontal sinus. Following the modifications, a visualization of 100% laterally was achieved with the 30- and 45 degree endoscopes and every lateral recess could be reached with the 70 degree suction. A mean increase of the angle of insertion of 25.3 and 59.6% was recorded after OT and PAR, respectively. CONCLUSIONS: IOD rather than APD defines the limits of the Draf III approach to the lateral frontal sinus and MLD/MOWD ratio can serve as a useful preoperative tool. Along to the already described OT, PAR increases visualization and reach of the lateral frontal sinus.

Tenosynovial giant cell tumor of the posterior pharyngeal space.

A 55-year-old man presented with dysphagia and a sore throat. Oral examination revealed a firm nodular mass in the midline of the pharyngeal wall. The tumor was en-bloc excised. Histopathology and immunohistochemistry confirmed the diagnosis of a tenosynovial giant cell tumor.

Biphenotypic sinonasal sarcoma: European multicentre case-series and systematic literature review.

Objective: Biphenotypic sinonasal sarcoma (BSNS) is a rare low-grade cancer that was included from the 4th edition of WHO classification of head and neck tumours. The purpose of this study is to analyse clinical behaviour, pattern of recurrences and survival outcomes of this neoplasm. Methods: Retrospective review of patients affected by BSNS who were treated via an endoscopic-assisted approach in 6 European tertiary-care referral hospitals. Cases of BSNS described in literature since 2012 to date were fully reviewed, according to PRISMA guidelines. Results: A total of 15 patients were included. Seven patients were treated via an endoscopic endonasal approach, 4 with endoscopic transnasal craniectomy, and 4 via a cranio-endoscopic approach. Adjuvant treatment was delivered in 2 cases. After a mean follow-up of 27.3 months, systemic metastasis was observed in 1 case; the 5-year overall survival and disease-free survival rates were 100% and 80 ± 17.9%, respectively. Conclusions: BSNS is a locally aggressive tumour with a low recurrence rate and encouraging survival outcomes if properly treated with surgical resection and free margins followed by adjuvant radiotherapy for selected cases. Endoscopic-assisted surgery is safe and effective as an upfront treatment within a multidisciplinary care protocol.

Inferior Turbinate Hypertrophy: A Comparison of Surgical Techniques.

Introduction Nasal obstruction is one of the most frequently reported symptoms in clinical practice. The second most common cause of nasal obstruction is inferior turbinate hypertrophy, a nasal pathology for which surgical treatment is often required. This study aims to determine the most effective surgical method in patients with inferior turbinate hypertrophy (ITH). Materials and methods The study was performed from September 2018 to October 2019 in the Otolaryngology-Head and Neck Surgery Department of the Evangelismos Hospital of Athens. The study population comprised 205 patients that underwent surgery and were monitored in the hospital. Radiofrequency ablation (RFA) was the method used in 73 patients, 68 patients were treated with the microdebrider-assisted turbinoplasty (MAT), and the remaining 64 patients were operated on using electrocautery (EC). Following surgery, postoperative complications were assessed and quantified. Results Overall, 205 patients underwent surgery. The first group (n=73) was operated on using radiofrequency ablation and had a complication rate of 30.1%. Out of 73 patients, 51 recovered without complications. The remaining 22 had complications, consisting of 16 patients with bleeding and six with postnasal drip. The second group (n=68) was treated using the microdebrider method. The complication rate was 26.5%, where 50 patients did not present with any symptoms post-operatively and 18 exhibited symptoms. Specifically, postnasal drip was more prevalent with this method as all 18 patients showed postnasal drip as their complication. The third group (n=64) was treated with electrocautery. Patients in this group had the most complications (n=24), 16 were attributed to postnasal drip and eight to infections, treated promptly with oral antibiotics. The complication rate using this method was 37.5%. Conclusion In our study, the microdebrider-assisted turbinoplasty offered the lowest complication rate, followed by radiofrequency ablation and electrocautery. However, all three methods managed to alleviate the nasal obstruction and treat inferior turbinate hypertrophy. More research is needed as a lack of consensus remains regarding the optimal surgical technique for lower turbinate hypertrophy.

Quality of life in sinonasal tumors: an up-to-date review.

PURPOSE OF REVIEW: To assess the impact of benign and malignant sinonasal tumors and their management on patients' Quality of Life (QOL) as measured by Patient Reported Outcome Measures (PROMS). RECENT FINDINGS: Although there is a growing consensus that endoscopic surgical management in carefully selected patients with sinonasal tumors is at least as (and probably more) effective than open resection, it is not clear to what extent this translates to better QOL outcomes. Earlier studies reported better outcomes in the emotional and physical function domains after endoscopic resection, and it seems that postsurgical morbidity is less in endoscopic compared to open approaches. QoL after endoscopic surgery for sinonasal and anterior skull base tumors seems to improve within several months of surgery in both benign and malignant tumor groups. However, patients with benign sinonasal tumors have a higher QOL pre and post operatively compared to those with malignancy mainly due to absence of (neo) - adjuvant radiotherapy and/or chemotherapy. Factors that seem to be associated with worse QoL include > 60 years, less than 6 months from surgery, prior and adjuvant chemo and radiotherapy, smoking history, advanced staging and malignancy. SUMMARY: There is not a universally accepted PROM for use in patients with sinonasal benign and malignant tumors: A variety of different PROMs have been used with different degrees of effectiveness. Most likely a combination of disease-specific (such as SNOT 22 and anterior skull base questionnaire) and generic (such as Short Form health survey questionnaire (SF-36) and Karnofsky Performance Status) health outcome measures provide the most insight into QOL of patients with sinonasal tumors. QOL of these patients appears to undergo a bimodal impact with patients experiencing an initial dip in QOL after surgical treatment followed by a slow improvement over time. However, while patients with benign tumors' return to their status quo ante QOL, this is not the case for patients with malignant tumors who stabilize at a lower than initially QOL. To a large extent this seems to be the effect of (neo) adjuvant chemo radiotherapy.

Characterization of outcomes and practices utilized in the management of internal carotid artery injury not requiring definitive endovascular management.

BACKGROUND: After internal carotid artery (ICA) injury during endoscopic skull base surgery, the majority of patients undergo ICA embolization or stenting to treat active extravasation or pseudoaneurysm development. However, management practices when embolization or stenting is not required have not been well described. The objective of this study was to determine how patients with ICA injury but no embolization, stenting, or ligation do long-term and ascertain the reconstruction methods utilized. METHODS: Twenty-nine cases of ICA injury were identified in an international multi-institutional retrospective review. Of these, we identified six cases that were not treated with embolization, stenting, or ICA sacrifice. Information was available for five cases. RESULTS: A muscle patch was used in the immediate repair of each case. A nasoseptal flap was used in one case. Prefabricated nasal tampons were used in all cases. Nasal packing was initially left in for a median of 7 days prior to removal. The initial muscle patch was reinforced with a second muscle graft in one case. One case demonstrated ICA bleeding at the time of packing removal and was repacked an additional week. Follow-up for each of these cases was at least 2 years. No cases of subsequent carotid rupture were found and none of these cases ultimately underwent endovascular stenting. Radiation or proton therapy has not been subsequently used in any of these patients. CONCLUSIONS: This study details the reconstruction, lessons learned, and long-term follow-up for five cases of ICA injury not treated with embolization, stenting, or ligation.

Efficacy and safety of treatment with biologicals for severe chronic rhinosinusitis with nasal polyps: A systematic review for the EAACI guidelines.

This systematic review evaluates the efficacy and safety of biologicals for chronic rhinosinusitis with nasal polyps (CRSwNP) compared with the standard of care. PubMed, Embase, and Cochrane Library were searched for RCTs. Critical and important CRSwNP-related outcomes were considered. The risk of bias and the certainty of the evidence were assessed using GRADE. RCTs evaluated (dupilumab-2, omalizumab-4, mepolizumab-2, and reslizumab-1) included 1236 adults, with follow-up of 20-64 weeks. Dupilumab reduces the need for surgery (NFS) or oral corticosteroid (OCS) use (RR 0.28; 95% CI 0.20-0.39, moderate certainty) and improves with high certainty smell evaluated with UPSIT score (mean difference (MD) +10.54; 95% CI +9.24 to +11.84) and quality of life (QoL) evaluated with SNOT-22 (MD -19.14; 95% CI -22.80 to -15.47), with fewer treatment-related adverse events (TAEs) (RR 0.95; 95% CI 0.89-1.02, moderate certainty). Omalizumab reduces NFS (RR 0.85; 95% CI 0.78-0.92, high certainty), decreases OCS use (RR 0.38; 95% CI 0.10-1.38, moderate certainty), and improves high certainty smell (MD +3.84; 95% CI +3.64 to +4.04) and QoL (MD -15.65; 95% CI -16.16 to -15.13), with increased TAE (RR 1.73; 95% CI 0.60-5.03, moderate certainty). There is low certainty for mepolizumab reducing NFS (RR 0.78; 95% CI 0.64-0.94) and improving QoL (MD -13.3; 95% CI -23.93 to -2.67) and smell (MD +0.7; 95% CI -0.48 to +1.88), with increased TAEs (RR 1.64; 95% CI 0.41-6.50). The evidence for reslizumab is very uncertain.

International Consensus Statement: Spontaneous Cerebrospinal Fluid Rhinorrhea.

BACKGROUND: The association between spontaneous cerebrospinal fluid (CSF) leak/rhinorrhea and idiopathic intracranial hypertension (IIH) has been increasingly recognized over the last years. However, considerable variability of opinion regarding the assessment, investigations, and management of patients with spontaneous CSF rhinorrhea remains. METHODS: A consensus group was formed from experts from Europe, Asia, Australia, South and North America. Following literature review and open discussions with members of the panel, a set of 61 statements was produced. A modified Delphi method was used to refine expert opinion with 3 rounds of questionnaires and a consensus group meeting in Santo-Rhino meeting in September 2019. RESULTS: Fifty statements (82% of total) on spontaneous CSF leak and IIH reached consensus. In 38 of 50 statements, the median response was 7 (strongly agree) and in the 12 remaining statements the median response was 6 (agree). Eleven statements were excluded because they did not reach consensus and one new statement was added during SantoRhino meeting. The final statements refer to patient history and clinical examination ("History taking should include presence of headache, tinnitus and visual defects"), investigations (role of Thin Slice Computed Tomography and CISS/FLAIR sequences in Magnetic Resonance Imaging), principles of management (watchful waiting or measures to reduce ICP are supplementary but cannot subsitute surgical closure), surgical technique, intraoperative, early postoperative and long term management. CONCLUSION: We present fifty consensus statements on the diagnosis, investigation, and management of spontaneous CSF rhinorrhea based on the currently available evidence and expert opinion. Although by no means comprehensive and final, we believe they can contribute to the standardization of clinical practice. Early diagnosis, prompt surgical closure of the defect, assesment for and treatment of potentially co-existing idiopathic intracranial hypertension in a comprehensive multidisciplinary approach are essential in order to successfully manage spontaneous CSF rhinorrhea, reduce associated morbidity and prevent recurrence.

Endoscopic Endonasal Prelacrimal Approach: Radiological Considerations, Morbidity, and Outcomes.

OBJECTIVE/HYPOTHESIS: This study describes a multicentric experience with the use of prelacrimal approach (PLA), focusing on preoperative radiological parameters potentially associated with surgical outcomes and postoperative morbidity. STUDY DESIGN: Retrospective case-series. METHODS: A retrospective review of patients undergoing PLA in three European referral centers was performed. The post-operative morbidity was analyzed in relation to two radiological parameters: width of prelacrimal recess (WPR) and internal angle of pyriform notch (APN). RESULTS: The study included 28 patients affected by Schneiderian papilloma (20 cases), inflammatory disease (6 cases), schwannoma (1 case), and osteoma (1 case). The most reported sequela was paresthesia of ipsilateral anterior superior alveolar process (25% of the cases). An association between post-operative morbidity and APN was observed (P = .047). CONCLUSIONS: Preoperative radiological evaluation of WPR is crucial in understanding the feasibility of the approach, while APN measurement may predict postoperative morbidity, which is paramount in the patients' counseling. LEVEL OF EVIDENCE: 4 case-series Laryngoscope, 131:1715-1721, 2021.

Advances in vascularized flaps for skull base reconstruction.

PURPOSE OF REVIEW: Advances in anterior skull base surgery have resulted in the increasing diversification of reconstructive techniques. New vascularized flaps have been suggested in the last years, some quite similar, whereas new uses and applications have been suggested for some vascularized flaps, which have already established their value over the last decades. In this article, we describe the developments in skull base reconstruction with vascularized flaps and analyse the international experience in the use of vascularized flaps published with a focus on the last 18 months. RECENT FINDINGS: Over the past 18 months, a number of novel or modified vascularized intranasal flaps have been described, focusing on reconstruction of larger defects, the medial orbital wall, the anterior skull base (septal flip-flap) and dissection of the nasoseptal flap from the SPA foramen. Extranasal vascularized flaps, which have been around for a long time, still have their rightful place in skull base reconstruction and have recently been adjusted for endoscopic use. SUMMARY: We present an overview of the latest developments in vascularized flaps (intranasal and extranasal), their new implications, their modifications and complications or predictions of viability.

Correction to: Multiple spontaneous skull base cerebrospinal fluid leaks: some insights from an international retrospective collaborative study.

In the original publication of the article, the following affiliation "Medical school, University of Nicosia, Nicosia, Cyprus" of the author "Christos Georgalas" was missed and included in this correction.

Quality of Life Outcomes in Frontal Sinus Surgery.

INTRODUCTION: Although significant experience has been gained in the technical nuances of endoscopic sinus surgery procedures, the patient-reported outcomes of frontal endoscopic sinus surgery procedures are still poorly understood. In this study we used the validated patient outcome measure Sino Nasal Outcome Test-22 (SNOT-22) to assess the preoperative and postoperative quality of life in patients undergoing extended endoscopic frontal sinus surgery (Draf type 2 and Draf type 3 procedures). METHODS: Out of a total of 680 patients undergoing endoscopic sinus and skull base surgery and 186 patients undergoing frontal sinus surgery, 99 chronic rhinosinusitis patients with (CRSwNP) or without (CRSnNP) nasal polyps undergoing Draf 2 or Draf 3 were assessed. RESULTS: The mean preoperative SNOT-22 was 45.6 points for patients undergoing Draf 2 and 59 for patients undergoing Draf 3, while the mean radiological Lund-Mackay Score was 14.3 and 14.5, respectively. Mean SNOT 22 improvement was 22.9 points for Draf 2 and 37 points for Draf 3 respectively and remained significant in all time intervals, including at 4 years after surgery. With the exception of loss of smell/taste, all symptoms improved by a far bigger extent in Draf 3 group, despite the considerably worse starting point. Effect size (Cohen / Standard Deviations) of Draf 3 was greatest in the following symptoms: "being frustrated/restless/irritable" (1.63), "nasal blockage" (1.43), "reduced concentration" (1.35), "fatigue" (1.29) "runny nose" (1.26) and "need to blow nose" (1.17). Frontal sinus (neo) ostium was patent (fully or partly) at last follow up in 98% of Draf 2 patients and in 88% of patients following Draf 3. Patients with non-patent frontal (neo-) ostium however had a mean postoperative SNOT 22 score of 43 compared to 20 of those with patent frontal sinus (neo-) ostium, although the difference was not statistically significant. CONCLUSION: Patients undergoing Draf 3 have a greater burden of disease, including both nasal and emotional/general symptoms compared to Draf 2 patients; surgery results in improvement in both groups, although Draf 3 patients have the greatest benefit, especially in emotional / general symptons. In this way both groups achieve similar postoperative quality of life, despite the different starting points.

Multiple spontaneous skull base cerebrospinal fluid leaks: some insights from an international retrospective collaborative study.

PURPOSE: Spontaneous skull base cerebrospinal fluid leaks occurring without any apparent cause are rare. But those patients that present such leaks simultaneously, or successively, in multiple locations are even rarer. Given the rarity of this condition, we collected data from other groups in a multicentre study to reach an adequate number of patients and draw some preliminary considerations. METHODS: We carried out a multicentre retrospective study on a cohort of patients treated at third level hospitals in Italy, Spain, United Kingdom and Greece for multiple spontaneous-CSF leaks and we compared them with a control group of patients treated for recurrent spontaneous-CSF leaks. Data regarding clinical aspects, radiological findings, surgical techniques and outcome were collected and preliminary considerations on the results were discussed. RESULTS: A total of 25 patients presented multiple simultaneous spontaneous CSF leaks while 18 patients fit with the criteria of recurrent spontaneous CSF leaks. Data analysis was conducted separately. CONCLUSIONS: Our understanding of the pathogenesis of this condition is currently very limited. A causative role of IIH may be present but the differences that emerged from the comparison with patients with recurrent fistulas seem to promote the possible role of other cofactors. A longer follow-up period is needed, and, in our opinion, prospective and multicentre studies are the only solution to seriously deal with such a complex topic.

Microbiotyping the Sinonasal Microbiome.

This study offers a novel description of the sinonasal microbiome, through an unsupervised machine learning approach combining dimensionality reduction and clustering. We apply our method to the International Sinonasal Microbiome Study (ISMS) dataset of 410 sinus swab samples. We propose three main sinonasal "microbiotypes" or "states": the first is Corynebacterium-dominated, the second is Staphylococcus-dominated, and the third dominated by the other core genera of the sinonasal microbiome (Streptococcus, Haemophilus, Moraxella, and Pseudomonas). The prevalence of the three microbiotypes studied did not differ between healthy and diseased sinuses, but differences in their distribution were evident based on geography. We also describe a potential reciprocal relationship between Corynebacterium species and Staphylococcus aureus, suggesting that a certain microbial equilibrium between various players is reached in the sinuses. We validate our approach by applying it to a separate 16S rRNA gene sequence dataset of 97 sinus swabs from a different patient cohort. Sinonasal microbiotyping may prove useful in reducing the complexity of describing sinonasal microbiota. It may drive future studies aimed at modeling microbial interactions in the sinuses and in doing so may facilitate the development of a tailored patient-specific approach to the treatment of sinus disease in the future.