360 Degrees Endoscopic Access to and Through the Orbit.

The treatment of pathologies located within and surrounding the orbit poses considerable surgical challenges, due to the intricate presence of critical neurovascular structures in such deep, confined spaces. Historically, transcranial and craniofacial approaches have been widely employed to deal with orbital pathologies. However, recent decades have witnessed the emergence of minimally invasive techniques aimed at reducing morbidity. Among these techniques are the endoscopic endonasal approach and the subsequently developed endoscopic transorbital approach (ETOA), encompassing both endonasal and transpalpebral approaches. These innovative methods not only facilitate the management of intraorbital lesions but also offer access to deep-seated lesions within the anterior, middle, and posterior cranial fossa via specific transorbital and endonasal corridors. Contemporary research indicates that ETOAs have demonstrated exceptional outcomes in terms of morbidity rates, cosmetic results, and complication rates. This study aims to provide a comprehensive description of endoscopic-assisted techniques that enable a 360° access to the orbit and its surrounding regions. The investigation will delve into indications, advantages, and limitations associated with different approaches, while also drawing comparisons between endoscopic approaches and traditional microsurgical transcranial approaches.

Salvage endoscopic nasopharyngectomy for recurrent nasopharyngeal carcinoma in a non-endemic area.

PURPOSE: To analyze oncological outcomes of endoscopic surgical treatment of locally recurrent EBV-related undifferentiated non-keratinizing nasopharyngeal carcinoma (uNK-NPC) in a non-endemic area. METHODS: Retrospective review of patients affected by recurrent uNK-NPC treated with nasopharyngeal endoscopic resection (NER) in a tertiary-care referral center from 2003 to 2022, by evaluating survival rates, prognostic factors, and follow-up strategies. RESULTS: The oncological outcomes of 41 patients were analyzed, over a mean follow-up period of 57 months. The 5-year overall, disease-specific, and disease-free survival of the cohort were 60.7% ± 8.9%, 69% ± 9%, and 39.7% ± 9.2%, respectively. The local (rT) and regional (rN) extension of recurrent disease, stage of disease, and status of resection margins appeared to significantly influence survivals. After a mean follow-up period of 21 months, a further recurrence after NER was observed in 36.6% of cases. Skull base osteonecrosis induced by previous irradiation and post-surgical bone remodeling represent the major challenges for early detection of further local relapses during postoperative follow-up. CONCLUSION: NER appeared as a safe and effective treatment for recurrent uNK-NPC. The adequate selection of patients eligible for NER is essential, to maximize the chances to cure and minimize the risk of local complications.

Symptomatic ecchordosis physaliphora of the upper clivus: an exceedingly rare entity.

OBJECTIVE: This paper highlights the management of 5 patients affected by symptomatic ecchordosis physaliphora (EP), treated via endoscopic endonasal transsphenoidal-transclival approach and contextual multilayer skull base reconstruction. A detailed analysis of each case is provided, along with the review of the current body of literature. METHODS: A retrospective review of patients treated by means of endoscopic endonasal approach for EP from 2010 to 2020 in the Otolaryngology and Neurosurgery Departments of a tertiary-care referral center for endoscopic skull base surgery was analyzed. Only adult patients with a definitive histopathological and immunohistochemical diagnosis of EP were included in the study. A systematic literature review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed for EP. RESULTS: Five cases of EP were retrieved and included in the study. Four patients presented with CSF leakage: in two cases after minor head trauma, in one case with associated bacterial meningitis, and in one case as only referred symptom. One patient complained diplopia due to VI cranial nerve palsy. No complications or recurrences of the disease were observed after a median follow-up of 37.2 months (range, 18-72 months). A total of 27 studies were identified with the systematic literature review, encompassing 30 patients affected by symptomatic EP who were addressed to surgical treatment. Twenty-five patients underwent complete surgical removal of the EP, while in 5 cases, only subtotal resection was performed. CONCLUSIONS: EP might result in a "locus minoris resistentiae" of the skull base, predisposing, in rare cases, to CSF leakage and meningitis, spontaneously or after minor trauma. In cases of symptomatic EP, endoscopic endonasal transsphenoidal-transclival approach represents a safe and effective technique for both EP resection and contextual skull base reconstruction.

Performing otolaryngological outpatient consultation during the Covid-19 pandemic.

BACKGROUND: The Covid-19 pandemic has had a profound impact on the Otolaryngology outpatient clinical practice, which is at high risk of respiratory viral transmission due to the close contact between the examiner and the patient's airway secretions [1]. Moreover, most otolaryngological procedures, including oropharyngoscopy, generate droplets or aerosols from high viral shedding areas [1]. Thus, only non-deferrable consultations were performed in the outbreak's acute phase. Along with the re-opening of elective clinical services and the impending second wave of the outbreak, a reorganization is necessary to minimize the risk of nosocomial transmission [1]. METHODS: This video (Video 1) shows how to safely conduct an outpatient Otorhinolaryngological consultation, focusing on complete ear, nose and throat examination, according to evidences from the published literature and Otolaryngological societies guidelines [2,3]. RESULTS: After telephonic screening, patients reporting Covid-19 symptoms or closecontact with a Covid-19 case within the last 14 days are referred to telehealth services [1-3]. To avoid crowding, the patient is admitted alone, after body temperature control, except for underage or disabled people [1]. The waiting room assessment must guarantee a social distance of 6 ft [1-3]. The consultation room is reorganized into two separate areas (Fig. 1): 1) a clean desk area, where an assistant wearing a surgical mask and gloves, handles the patient's documentation and writes the medical report, keeping proper distance from the patient, and 2) a separate consultation area, where the examiner, equipped with proper personal protective equipment (Fig. 2) [3,4], carries out the medical interview and physical examination. Endoscopic-assisted ear, nose and throat inspection using a dedicated monitor allows the examiner to maintain an adequate distance from the patient throughout the procedure while providing an optimal view (Figs. 3-6) [3]. Recent evidence shows that nasal endoscopy does not increase droplet production compared to traditional otolaryngological examination [5]. When necessary, nasal topic decongestion and anesthesia must be performed using cottonoids rather than sprays [3]. The patient keeps the nose and mouth covered throughout the consultation, lowering the surgical mask on the mouth for nasal endoscopy and removing it only for oropharyngoscopy. After the consultation, the doffing procedure must be carried out carefully to avoid contamination [4]. All the equipment and surfaces must undergo high-level disinfection with 70% alcohol or 0.1% bleach solutions [3]. Proper room ventilation must precede the next consultation [3]. CONCLUSIONS: The hints provided in this video are useful to ensure both patient and examiner safety during Otolaryngological outpatient consultations and to reduce SARS-CoV-2 transmission.

Changes in the use of Otorhinolaryngology Emergency Department during the COVID-19 pandemic: report from Lombardy, Italy.

PURPOSE: This paper aims to report the impact of COVID-19 outbreak on Emergency Ear nose and Throat (ENT) activity, in Lombardy (Italy), during COVID-19 pandemic. METHODS: The number of accesses to Emergency Department requiring ENT consultations between February 21st and May 7th, 2020, was retrospectively collected, along with the conditions treated. Data were stratified in 1-week time spans, to evaluate the evolving trends during the on-going epidemic and a comparison with the two previous years was performed. RESULTS: A significant reduction in the number of consultations performed during the pandemic was observed, as high as - 91% compared to the same period of 2018. CONCLUSION: Multiple reasons can explain such a reduction of Emergency ENT consultations, not least the fear of potentially being infected by SARS-CoV-2 by while accessing the hospital. The analysis performed might be useful as a starting point for a future reorganization of first aid consultations once the epidemic will be resolved.

Transoral Robotic Surgery in the Management of a Tongue Base Schwannoma.

Schwannomas are the most common benign tumors arising from the peripheral nerve sheath, and the intraoral location is very atypical, representing less than 1% of all cases. Surgical excision is the treatment of choice, and a variety of surgical approaches have been described. The authors report the first described case of tongue base schwannoma treated with transoral robotic surgery (TORS). A 47-years-old female patient complaining mild dysphagia and snoring, presented a submucosal swelling at the right side of the tongue base. MRI showed a large well-circumscribed solid mass, homogeneously isointense in T1WI and hyperintense on T2WI, with no lymph node metastasis. According to size, location and radiological characteristic of the mass a TORS approach was chosen. An extracapsular dissection was performed, and the lesion was completely removed with no intraoperative complications. The final diagnosis based on histopathological examination and IHC analysis (S-100 positive) was a schwannoma of the tongue base. The post-operative course was uneventful, and no recurrence was observed after 6 months of follow-up. This study demonstrates the feasibility of TORS in the treatment of a tongue base schwannoma. This is a valid alternative to the common transoral approach in order to avoid more invasive external approaches, and further studies are recommended in order to clarify if this approach could be proposed as the first line treatment in selected cases.

Septal branches of the anterior ethmoidal artery: anatomical considerations and clinical implications in the management of refractory epistaxis.

PURPOSE: Epistaxis is a commonly presenting complaint. In severe cases, nosebleeds may occur despite antero-posterior nasal packing and often in the absence of identifiable sources of bleeding. In such cases, epistaxis may occur from septal branches of the anterior ethmoidal artery (sbAEA). The purposes of this study are to highlight the clinical role of the sbAEA in different fields of endoscopic endonasal surgery and to evaluate the efficacy and safety of their selective endoscopic endonasal ligation in the management of refractory epistaxis. METHODS: A retrospective review was performed of all patients presenting with epistaxis who underwent endoscopic endonasal coagulation of sbAEA in three Italian tertiary-care referral centers between October 2010 and October 2017. RESULTS: A total of 30 patients met the inclusion criteria. Sixteen patients had never experienced nosebleeds before, while 14 patients recalled previous epistaxes. Seventeen patients were treated under local anesthetic, while 13 required general anesthesia. No intra- or post-operative complications were observed and none of the patients received nasal packing after the procedure. In all cases the coagulation was effective in controlling the bleeding, with only two relapses in the series (2/30, 6.7%). CONCLUSIONS: The sbAEA are of great interest in endoscopic endonasal surgery, both as surgical landmarks and as feeding vessels for a variety of pedicled nasal flaps. What is more, they can be crucial for the management of refractory epistaxis. Their selective endoscopic coagulation represents an effective and safe procedure in cases of difficult-to-control epistaxis from the upper nasal fossa, with several advantages over nasal packing.

Surgical management of advanced sinonasal cancer: a 10-year mono-institutional experience.

Objective: Endoscopic endonasal surgery is effective in the treatment of sinonasal cancers. However, in cases of well-differentiated locally advanced neoplasms as well as recurrences, the most appropriate treatment is debated. The purpose of this study is to report a mono-institutional experience on craniofacial surgery performed in a tertiary-care referral centre. Methods: This was a retrospective analysis of 90 patients treated with transcranial and/or transfacial resection for sinonasal cancer between 2010 and 2020. Outcome measures included overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS) and recurrence-free survival (RFS). Results: The 5-year OS, DSS and DFS were 48.2%, 60.6% and 28.7%, respectively. Factors correlated with prognosis were pT-classification (p = 0.002), histotype (p = 0.012) and dural involvement (p = 0.004). Independent prognostic factors were orbital apex infiltration (p = 0.03), age (p = 0.002) and adjuvant therapy (p = 0.03). Conclusions: When endoscopic endonasal surgery is contraindicated and chemoradiotherapy is not appropriate, craniofacial and transfacial approaches still represent an option to consider, despite the non-negligible morbidity.

Endoscopic-assisted transorbital extended orbital exenteration: A multi-institutional preclinical study.

BACKGROUND: Sinonasal malignancies with orbital invasion have dismal prognosis even when treated with orbital exenteration (OE). Sugawara et al. developed a surgical strategy called "extended-OE (EOE)," showing encouraging outcomes. We hypothesized that a similar resection is achievable under endoscopic guidance through the exenterated orbit (endoscopic-EOE). METHODS: The study was conducted in three institutions: University of Vienna; Mayo Clinic; University of Insubria; 48 orbital dissections were performed. A questionnaire was developed to evaluate feasibility and safety of each step, scoring from 1 to 10, ("impossible" to "easy," and "high risk" to "low risk," respectively), most likely complication(s) were hypothesized. RESULTS: The step-by-step technique is thoroughly described. The questionnaire was answered by 25 anterior skull base surgeons from six countries. Mean, median, range, and interquartile range of both feasibility and safety scores are reported. CONCLUSIONS: Endoscopic-EOE is a challenging but feasible procedure. Clinical validation is required to assess real-life outcomes.

Comprehensive access strategies to the frontal sinus.

PURPOSE OF REVIEW: Despite the impressive evolutions in endoscopic endonasal approaches and instrumentations, the frontal sinus remains a challenging area. Different surgical options have been described over the years, but the main criticism lies in choosing the most suitable approach for a given case, based on the anatomy of each patient and the disease to treat. The purpose of this study is to provide a comprehensive review of surgical access strategies currently available to address the frontal sinus, including both endonasal and traditional external procedures, analysing indications, contraindications, complications and outcomes. RECENT FINDINGS: Frontal sinus surgery includes minimally invasive endonasal approaches (balloon dilatation, Draf type I); extended endonasal approaches (Draf type IIA-IIB-IIC, Draf type III and their modifications via orbital transposition and contralateral pyriform aperture resection); external procedures (superior eyelid incision, frontal osteoplastic flap, Riedel procedure, Riedel-Mosher operation); and combined approaches. SUMMARY: Recent advances in endoscopic endonasal techniques have deeply reshaped the surgical options to manage frontal sinus diseases, in an attempt to minimize the invasiveness of the procedures and maximize their outcomes. Traditional external procedures should be used in selected cases nonamenable for endonasal surgery. The appropriate selection of cases appears to be of paramount importance to obtain successful outcomes.

Sinonasal Malignancies Involving the Frontal Sinus: A Mono-Institutional Experience of 84 Cases and Systematic Literature Review.

Frontal sinus involvement by malignant tumors is a rare finding. Therefore, a systematic literature review along with a personal case series may contribute to defining more accurately the epidemiology, treatment options, and outcomes of these neoplasms. This is a retrospective review of patients affected by frontal sinus malignancies surgically treated in a tertiary-care referral center over a period of 20 years. Moreover, a systematic literature review of studies describing frontal sinus cancers from 2000 to date was performed according to PRISMA guidelines in order to analyze current evidence about the treatment and outcomes of such a rare disease. Our retrospective review was basedon 84 cases, treated with an exclusive endoscopic approach in 43 cases (51.2%), endoscopic approach with frontal osteoplastic flap in 6 cases (7.1%), and transfacial or transcranial approaches in 35 cases (41.7%). The five-year overall, disease-specific, disease-free, and recurrence-free survivals were 54.6%, 62.6%, 33.1%, and 59.1%, respectively. Age, dural involvement, type of surgical resection, and surgical margin status were significantly associated with the survival endpoints. In conclusion, the involvement of the frontal sinus is associated with a poor prognosis. Multidisciplinary management, including specific histology-driven treatments, represents the gold standard for improving outcomes and minimizing morbidity.

The Role of the Transorbital Superior Eyelid Approach in the Management of Selected Spheno-orbital Meningiomas: In-Depth Analysis of Indications, Technique, and Outcomes from the Study of a Cohort of 35 Patients.

Objective Primary goal in spheno-orbital meningioma (SOM) surgery still remains complete resection. Nevertheless, given their highly infiltrative nature, a growing body of literature suggests to shift toward function-sparing surgeries. We here present our experience in the management of SOMs through the endoscopic superior eyelid approach (SEA). Methods Surgical database from our multidisciplinary work group was retrospectively reviewed to identify patients treated for SOMs in the last 10 years by our senior authors, analyzing and correlating clinical, radiological, and outcome variables among the different approaches used. Results There were 35 patients (mean age of 57.3 ± 12.86 years), with a mean follow-up of 31.5 months (range: 6-84 months). The most common preoperative complaint was proptosis (62.9%) followed by diplopia and visual deficit. Greater and lesser sphenoid wings were the areas mainly involved by the pathology (91.4% and 88.6%, respectively), whereas orbital invasion was evidenced in one-third of cases. Patients were operated on through craniotomic (48.6%), endoscopic superior eyelid (37.1%), and combined cranioendoscopic (14.3%) approaches. Simpson grades 0 to II were accomplished in 46.2% of SEA and 76.5% of craniotomies. All patients with a preoperative visual deficit improved in the postoperative period, independently from the approach used. On patients who underwent endoscopic SEA, there was improved their short-/long-term postoperative Karnofsky Performance Status. Conclusions Endoscopic SEA is a safe and effective alternative to transcranial approaches in very selected cases of SOMs, where the planned primary objective was to obtain a maximally safe resection, aimed at symptom relief, rather than a gross total resection at any cost.

Endoscopic Endonasal Pituitary Hemi-Rotation Approach to the Upper Clivus: Anatomical Study and Clinical Report.

AIM: To report on the endoscopic endonasal pituitary hemi-rotation approach (EPHRA) in a preclinical setting and in a preliminary clinical experience. MATERIAL AND METHODS: EPHRA was performed in five fresh-frozen head and neck specimens (a total of 10 sides) and in a selected case of a right-sided dorsum sellae chordoma. RESULTS: The approach described allowed exposure of the lateral part of the upper clivus in all the specimens and in the case reported. To evaluate the maximum possible degree of hypophyseal hemi-rotation, the hemi-rotation angle (HRA) of the approach was measured and reported for all sides of the specimens. In 9 out of 10 cadaver head sides, and in the clinical case, it was possible to avoid sectioning of the inferior hypophyseal artery. No complications occurred during or after the procedure. CONCLUSION: EPHRA represents an addition to the techniques already described and finds indications in case of non-massive neoformations of the lateral upper clivus. Clinical applications and limitations still need to be clarified in further clinical studies.

Long Term Outcomes of Nasoseptal Perforation Repair With an Anterior Ethmoidal Artery Flap.

BACKGROUND: Nasoseptal perforation repair is a challenging condition with no standard technique for repair recognized. METHODS: A case series of consecutive patients who underwent nasoseptal perforation repair with an anterior ethmoidal artery flap was conducted. Demographic data, preoperative features of the perforation and postoperative outcomes were analyzed. Closure rate, complications and persistence of nasal symptoms were documented. RESULTS: Thirty-two patients were included in the study. The average perforation diameter was 1.48 cm (range: 0.4-3 cm). Iatrogenic trauma was the most common cause (56% of patients). Nine cases ended up being idiopathic. The overall closure rate was 81%, but 87.5% when perforation had a 2-cm diameter or less. Of the six failures, 2 were due to flap necrosis and 4 to a residual anterior perforation. Despite the persistence, 2 patients solved their symptoms. One patient underwent revision surgery. CONCLUSION: The anterior ethmoidal artery flap is a reliable and minimal invasive technique for closure of symptomatic perforations. For defects larger than 2 cm, a lower success rate and additional reconstructive measures should be considered. Objective questionnaires are needed in order to evaluate functional outcomes.

Endoscopic-assisted orbital exenteration: Technical feasibility and surgical results from a single-center consecutive series.

The purposes of this study were to describe the endoscopic-assisted orbital exenteration surgical techniques, to report preliminary outcomes and to discuss advantages, indications and limitations of this approach. All patients who underwent endoscopic-assisted orbital exenteration at a single tertiary-care center were retrospectively reviewed. A concomitant reconstruction was performed in all cases. The extent of surgical resection was tailored to the size and location of tumor and was classified into four subtypes. A total of 40 patients were included in this series. Orbital exenteration type 1 was performed in 7 cases, type 2 in 11 cases, type 3 in 19 cases, and type 4 in 3 cases. The reconstruction was performed with a pedicled temporal flap in 5 patients and with a free vascularized flap in 34 cases. A radical resection of disease was obtained in 32 cases. After a mean follow-up of 36 months, 14 patients died of disease, one patient died of other causes, 7 are alive with disease, and 18 patients are currently alive without evidence of disease. The preliminary data emerging from this case-series support the feasibility and safety of endoscopic-assisted orbital exenteration.

Maxillary Sinus Floor Infiltration: Results From a Series of 118 Maxillary Sinus Cancers.

OBJECTIVES/HYPOTHESIS: Maxillary cancers are rare and aggressive tumors, which can spread beyond the sinus bony walls. Preoperative assessment of infiltration of maxillary sinus floor (MSF) is paramount for surgical planning, as palatomaxillary demolition significantly impacts patients' quality of life. This study investigates the challenges involved in the preoperative and intraoperative evaluation of MSF infiltration and analyzes its prognostic relevance. STUDY DESIGN: Retrospective case series. METHODS: A retrospective review of patients treated for sinonasal malignancies at a single Institution was performed. Patients receiving surgical-based treatment with curative intent for primary maxillary sinus cancers, between January 2000 and November 2019, were included. RESULTS: A cohort of 118 patients was analyzed. By comparing intraoperative findings (endoscopic assessment and frozen sections) with preoperative radiological assessment, diagnostic changes with regard to MSF infiltration were found in 27.1% (32/118 cases). MSF infiltration negatively affected the prognosis in both univariate and multivariate analyses in the overall population. In the subgroup of pT1-T3 tumors, MSF infiltration was significantly associated with reduced overall (P = .012), disease-free (P = .011), and distant recurrence-free (P = .002) survival rates. Conversely, pT classification was not able to stratify patients according to prognosis, mainly because early-staged cancers (pT1-T2) with MSF infiltration showed reduced survival rates, similar to those observed in pT3 cancers. CONCLUSIONS: Preoperative imaging should be integrated with intraoperative findings based on endoscopic inspection and frozen sections. Future studies are required to investigate the opportunity to incorporate MSF infiltration in the TNM staging system, considering its crucial role in defining the extent of surgery and its potential as prognosticator. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:26-35, 2022.

Juvenile Angiofibroma: What Is on Stage?

OBJECTIVES/HYPOTHESIS: The aim of the present study is to validate and compare four of the most widely used staging systems for juvenile angiofibroma on a homogeneous cohort of patients. STUDY DESIGN: Retrospective case series. METHODS: A retrospective review of patients treated with endoscopic or endoscopic-assisted surgical resection between 1999 and 2020 was carried out. Each case was classified according to the following staging systems: Andrews-Fisch (1989), Radkowski (1996), University of Pittsburgh Medical Center (2010), and Janakiram (2017). Spearman's rank correlation test and areas under the curve of receiver operator curves were used to assess the correlation between outcomes of interests (blood loss, surgical time, need for transfusion, and persistence of disease) and stage of disease. RESULTS: Seventy-nine patients were included, with a median follow-up time of 25 months (range 12-127 months). Median surgical time was 217 minutes (range 52-625). Median blood loss was 500 mL (range 40-5200) and 27 patients (34.2%) required blood transfusions. Seven patients (8.9%) showed persistence of disease. All classification systems showed a similar association with blood loss, surgical time, persistence of disease, and need for transfusion. CONCLUSIONS: Involvement of the infratemporal fossa and intracranial extension was identified as red flags for surgical planning and preoperative counseling, as associated with increased risk for transfusion and persistent/recurrent disease, respectively. No classification system was found to be better than the others in predicting the most important outcomes. Therefore, the simplest and most easily applicable system would be the preferred one to be used in clinical practice. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:1160-1165, 2022.

Patterns of recurrences in sinonasal cancers undergoing an endoscopic surgery-based treatment: Results of the MUSES* on 940 patients: *MUlti-institutional collaborative Study on Endoscopically treated Sinonasal cancers.

OBJECTIVES: The improvements in survival with expansion of the survivors' population, along with evolution of endoscopically-based treatment modalities, have contributed to emphasize the clinical relevance of recurrences in sinonasal cancers. However, at present, literature is scant regarding the pattern of recurrences and the therapeutic strategies available to manage long survivors who experienced single or multiple failures. The aim of the present study was to analyze sinonasal cancers recurrences to provide data regarding rates and patterns of relapse, predictors of failure and prognostic impact of the recurrence. MATERIALS AND METHODS: All patients receiving multimodal treatments including endoscopic surgery between 1995 and 2021 in three European referral centers were included. Statistical analysis of survival was performed through univariable, multivariable and unidirectional multistate models. Survival after recurrence analysis was implemented for patients experiencing at least one recurrence. RESULTS: The 5- and 10-year recurrence free survival rates were 34.1% and 38.4% for the whole population. With a mean follow-up time of 60 months, a global recurrence rate of 32.9% was observed. The 5- and 10-year survival after recurrence rates were 27.2% and 21.7%, respectively. Incidence and rates of recurrences were significantly associated with histology subtypes. CONCLUSION: This study provides valuable oncologic outcomes regarding a large homogenous cohort of patients affected by sinonasal malignances treated within a multimodal framework, emphasizing the strong correlation of histologic type with prognosis, as well as with pattern of recurrences.

The MUSES∗: a prognostic study on 1360 patients with sinonasal cancer undergoing endoscopic surgery-based treatment: ∗MUlti-institutional collaborative Study on Endoscopically treated Sinonasal cancers.

BACKGROUND: Over the last 2 decades, transnasal endoscopic surgery (TES) has become the most frequently employed surgical technique to treat sinonasal malignancies. The rarity and heterogeneity of sinonasal cancers have hampered large non-population-based analyses. METHODOLOGY: All patients receiving TES-including treatment between 1995 and 2021 in 5 referral hospitals were included. A prognostic study was performed, and multivariable models were transformed into nomograms. Training and validation sets were based on results from 3 European and 2 non-European centres, respectively. RESULTS: The training and validation set included 940 and 420 patients, respectively. The mean age at surgery, primary-versus-recurrent presentation, histology distribution, type of surgery, T category and type of adjuvant treatment were differently distributed in the training and validation set. In the training set, 5-year overall survival and recurrence-free survival with a 95%-confidence interval were 72.7% (69.5-76.0%) and 66.4% (63.1-69.8%), respectively, significantly varying with histology. At multivariable analyses, age, gender, previous treatment, the extent of resection on the cranial, lateral and posterolateral axes, grade/subtype, T category, nodal status, margin status and adjuvant treatment were all associated with different prognostic outcomes, displaying a heterogeneous significance and effect size according to histology. The internal and external validation of nomograms was satisfactory (optimism-corrected C-index >0.7 and cumulative area under curve >0.7) for all histologies but mucosal melanoma. CONCLUSIONS: Outcomes of TES-based treatment of sinonasal cancers vary substantially with histology. This large, non-population-based study provides benchmark data on the prognosis of sinonasal cancers that are deemed suitable for treatment including TES.