Oxygen matters: hypoxia as a pathogenic mechanism in rhinosinusitis

The airway epithelium is the first place, where a defense mechanism is initiated against environmental stimuli. Mucociliary transport (MCT), which is the defense mechanism of the airway and the role of airway epithelium as mechanical barriers are essential in innate immunity. To maintain normal physiologic function, normal oxygenation is critical for the production of energy for optimal cellular functions. Several pathologic conditions are associated with a decrease in oxygen tension in airway epithelium and chronic sinusitis is one of the airway diseases, which is associated with the hypoxic condition, a potent inflammatory stimulant. We have observed the overexpression of the hypoxia-inducible factor 1 (HIF-1), an essential factor for oxygen homeostasis, in the epithelium of sinus mucosa in sinusitis patients. In a series of previous reports, we have found hypoxia-induced mucus hyperproduction, especially by MUC5AC hyperproduction, disruption of epithelial barrier function by the production of VEGF, and down-regulation of junctional proteins such as ZO-1 and E-cadherin. Furthermore, hypoxia-induced inflammation by HMGB1 translocation into the cytoplasm results in the release of IL-8 through a ROS-dependent mechanism in upper airway epithelium. In this mini-review, we briefly introduce and summarize current progress in the pathogenesis of sinusitis related to hypoxia. The investigation of hypoxia-related pathophysiology in airway epithelium will suggest new insights on airway inflammatory diseases, such as rhinosinusitis for clinical application and drug development.

Sinonasal pleomorphic adenoma: A single institution case series combined with a comprehensive review of literatures

OBJECTIVE

This study aimed to reveal diagnosis, management, and treatment outcome characteristics of sinonasal pleomorphic adenoma and to identify predictors for disease recurrence.

METHODS

This study comprised a retrospective review of data from seven patients with sinonasal pleomorphic adenoma who were treated by the authors at a tertiary medical center between January 2005 and May 2017. In addition, the MEDLINE database was searched for literature published in English. A systematic review of the published articles was performed.

RESULTS

A total of 42 articles were eligible for review. Data from the seven treated patients and 101 patients described in the literature were included in the analysis. An endoscopic approach was employed in all cases treated at our institution, and recurrence was found in one patient with a large, 5.5-cm tumor. In reviewing prior publications, the mean age at surgery was 45.4 years, and the primary sign at diagnosis was nasal obstruction. The most common primary tumor site was the nasal septum (57.4%), and the mean tumor size was 3.6cm (range, 0.5-10cm) in 76 cases for which detailed information was available. Endoscopic endonasal resection achieved successful oncologic control in applied cases (25/25, 100%). Recurrence was found in eight of 101 patients. Multivariate analysis identified tumor origin of the paranasal sinus (adjusted OR 31.000, p=0.016) as being significantly associated with a high prevalence of recurrence.

CONCLUSION

Pleomorphic adenoma is a rare benign tumor of the sinonasal tract. Surgery that achieves clear margins is the treatment of choice. The tumor may be accessible via an endoscopic endonasal approach in most cases, although incomplete resection of the tumor stem may allow for tumor recurrence. In addition, our findings suggest that a tumor originating from the paranasal sinus is significantly associated with a high prevalence of recurrence.

Damage of Inner Ear Sensory Hair Cells via Mitochondrial Loss in a Murine Model of Sleep Apnea With Chronic Intermittent Hypoxia

Study Objectives

Investigating the exact pathophysiology of obstructive sleep apnea syndrome (OSAS)-induced hearing loss is critical. We sought to verify the hypothesis that a correlation exists between mitochondrial dysfunction in inner ear hair cells and the auditory dysfunction induced by chronic intermittent hypoxia (CIH) in a murine model of sleep apnea.

Methods

C57BL/6J adult male mice were randomized to 4 weeks of CIH (n = 12) or normoxia (Sham) (n = 12). Hearing threshold was determined by auditory brainstem response. The activity of mitochondria was compared between CIH and Sham mice. Histological assessment and transmission electron microscopy were performed for assessing morphologic changes in mitochondria. The number of mtDNA copies as well as the levels of PGC1-α, Tfam, and VDAC (voltage-dependent anion channel) were determined in the hair cells of CIH mice.

Results

We observed that hearing ability in CIH mice was impaired and hair-cell mitochondria in CIH mice were fewer compared to that in Sham and also displayed an aberrant morphology. The mRNA levels of PGC-1α and Tfam were higher in the CIH group than in the Sham group. Moreover, the expression of VDAC was increased in the tectorial membrane, the basilar membrane, and especially in the inner hair cells of CIH mice.

Conclusions

This study using CIH mice as a model for OSAS provides evidence of an association between OSAS and auditory function alteration, as well as of mitochondria being part of the pathophysiology of hearing impairment. Further investigation is required to determine whether mitochondria could serve as a valid target for preventive or therapeutic purposes.

Better surgical outcome by image-guided navigation system in endoscopic removal of sinonasal inverted papilloma

PURPOSE

The purpose of this study was to validate and compare treatment outcomes for endoscopic resection of sinonasal inverted papilloma (IP) with or without the use of a navigation system.

MATERIALS AND METHODS

A total of 58 patients who underwent endoscopic resection of sinonasal inverted papilloma by a single surgeon from 2007 to 2016 at our institution were retrospectively reviewed. Depending on the use of the navigation system, subjects were divided into two groups: a conventional endoscopic resection group without navigation system (CER group) and a navigation-assisted endoscopic resection group (NER group).

RESULTS

There were 24 patients (41.4%) in the CER group and 34 patients (58.6%) in the NER group. Treatment outcomes showed that navigation-assisted endoscopic resection was a more beneficial surgical technique than conventional endoscopic resection for sinonasal IP. Post-surgical recurrence was noted in seven cases (29.2%) in the CER group and two cases (5.9%) in the NER group. Accordingly, the recurrence rate was significantly less in the NER group compared to the CER group (p = 0.026). There were two cases of complications (8.3%) in the CER group comprising cerebrospinal fluid leak and periorbital fat exposure, while no complications were noted for the NER group (p = 0.167).

CONCLUSION

This study demonstrated that navigation-assisted endoscopic removal of sinonasal IP is helpful for reducing recurrence and avoiding surgical complications. Therefore, navigation systems should be always considered when performing endoscopic removal of sinonasal IP.

Radiological comparison of inferior turbinate hypertrophy between allergic and non-allergic rhinitis: does allergy really augment turbinate hypertrophy?

BACKGROUND

Inferior turbinate hypertrophy could be a result of allergic rhinitis (AR) that leads to nasal congestion and nasal airway obstruction, which is the most bothersome complaint in patients with AR. However, evidence regarding whether patients with AR have a more hypertrophied inferior turbinate than do patients with non-AR is lacking.

OBJECTIVE

We aimed to evaluate the degree of inferior turbinate hypertrophy according to the presence of AR using radiological measurements of the inferior turbinate.

METHODS

For evaluating the inferior turbinate, which contributes to nasal obstruction in patients with AR, we enrolled 90 adult patients with septal deviation and divided them into two groups (AR group: n = 49; non-AR group: n = 41). Allergic rhinitis was diagnosed according to the presence of an allergic history, positive multiple allergen simultaneous test, and serological total immunoglobulin E level (≥ 100 kU/L). We analyzed the minimal cross-sectional area on acoustic rhinometry for both groups. The bilateral total width as well as medial mucosa and nasal cavity space in the anterior and posterior portions of the inferior turbinate were measured using computed tomography.

RESULTS

We could not find any significant differences in the anterior and posterior dimensions of the inferior turbinate, intranasal space, and choanal spaces between the AR and non-AR groups. Instead, the anterior part of the inferior turbinate in both the groups showed significant differences between the deviated and contralateral sides. The contralateral side had a larger width than did the deviated side, but no significant difference was noted in the posterior portion of the inferior turbinate.

CONCLUSION

The degree of inferior turbinate hypertrophy showed no difference between patients with and without AR. Therefore, we suggest that surgical treatment for reducing the size of the inferior turbinate hypertrophy should be considered when performing septoplasty in patients with symptoms of nasal obstruction, regardless of the presence of AR.

Effects of continuous positive airway pressure therapy on left ventricular diastolic function: a randomised, sham-controlled clinical trial

Continuous positive airway pressure (CPAP) therapy may decrease left ventricular (LV) loads and improve myocardial oxygenation. In this study, we investigated the effect of CPAP on LV diastolic function compared with sham treatment in patients with severe obstructive sleep apnoea (OSA).

This 3-month prospective single-centre randomised sham-controlled trial analysed 52 patients with severe OSA. Patients were randomly assigned (1:1) to receive either CPAP or sham treatment for 3 months. The main investigator and patients were masked to the trial randomisation. The primary end-point was change of early diastolic mitral annular (e′) velocity over the 3-month period. Secondary end-points were pulse wave velocity (PWV), 24-h ambulatory blood pressure (BP) and variables of ventricular-vascular coupling at 3 months.

After 3 months of follow-up, CPAP treatment significantly increased the e′ velocity, and was greater than the sham treatment (0.65±1.70 versus −0.61±1.85 cm·s−1, p=0.014). The PWV, 24-h mean diastolic BP, night-time diastolic BP, arterial elastance index and ventricular-vascular coupling index after 3 months of follow-up decreased significantly in the CPAP group.

In patients with severe OSA, CPAP treatment for 3 months improved LV diastolic function more than sham treatment, and was accompanied by improvements in arterial stiffness and ventricular-vascular coupling.

Recurrent Obturator Hernia as a Cause of Nonspecific Abdominal Pain: A Case Report

Many patients visit the emergency department (ED) with abdominal pain. Sometimes, physicians are faced with diagnostic challenges, particularly for older patients. We recently had an elderly female patient who visited the ED several times with non-specific abdominal pain caused by an unusual hernia. One year before, an 81-year-old female visited our ED complaining of abdominal pain radiating to the right inguinal/femoral area. An incarcerated obturator hernia was found on an abdomino-pelvic computed tomography (CT) scan, and she underwent a laparoscopic hernioplasty. However, 1 year later, she revisited complaining of abdominal pain similar to the previous episode. Eventually, the diagnosis of recurrent obturator hernia was made, and a second operation was performed. An obturator hernia may be the cause of non-specific abdominal pain and small bowel obstruction in elderly emaciated females. Recognising the clinical signs and characteristics of this disease is necessary for a prompt diagnosis and treatment.

Hypoxia Modulates Epithelial Permeability via Regulation of Vascular Endothelial Growth Factor in Airway Epithelia

Hypoxia resulting from occlusion of the sinus ostium is known to be one of the major pathogenic mechanisms of sinusitis. Hypoxia-inducible factor (HIF)-1 is a widely known transcription factor that induces the cellular response to hypoxic conditions and activates the transcription of several genes, including vascular endothelial growth factor (VEGF). We hypothesized that induced permeability caused by hypoxia is a major pathophysiologic mechanism of upper airway diseases, such as sinusitis. The aim of this study was to investigate the mechanism of hypoxia-induced hyperpermeability, which mediates increased paracellular permeability and enhanced microbial invasiveness in the airway epithelium. We show that expression of VEGF mRNA and protein and HIF-1α protein increased as a function of time under hypoxia in normal human nasal epithelial cells. Our results also indicate that VEGF expression was induced by transfection with a mammalian expression vector encoding HIF-1 but down-regulated by transfection with small interfering RNA specific for HIF-1α under hypoxic conditions. Results of a transepithelial permeability assay measuring transepithelial electrical resistance indicated that permeability was increased as a function of time under hypoxia and was rescued by anti-VEGF monoclonal antibody (bevacizumab) and small interfering RNA specific for HIF-1α. We detected up-regulated HIF-1α and VEGF expression in mucosal epithelium samples from patients with sinusitis compared with normal mucosal epithelium using Western blotting and immunohistochemical staining. In conclusion, we suggest that the hypoxia-HIF-1α-VEGF axis plays an important role in hyperpermeability of airway epithelial cells, implying a role in the pathophysiology of upper respiratory tract diseases, such as sinusitis.

Chronological Change of Right Ventricle by Chronic Intermittent Hypoxia in Mice

Study Objective

No studies have investigated sequential changes in the heart on magnetic resonance imaging (MRI), along with observation of functional lung phenotypes and genetics, over the duration of chronic intermittent hypoxia (CIH). We investigated chronological changes in heart and lung phenotypes after CIH using a mouse model to provide new insights into the pathophysiology of sleep apnea-induced cardiovascular disease.

Methods

C57BL/6J adult male mice were randomized to 4 or 8 weeks of CIH. Cardiac cine-MRI images were analyzed to assess functional parameters of right ventricle (RV). Histopathological features of myocytes and pulmonary vessels, as well as genes involved in the endothelin (ET) system, were investigated.

Results

Function of the RV reduced significantly at 4 weeks and continuously decreased following another 4 weeks of CIH, although the rate of decrease was attenuated. Notably, persistence of reduced ejection fraction and end-systole RV wall thickness (WT) and increases in the ET system of the lungs and blood strongly implied the development of pulmonary hypertension after 8 weeks of CIH.

Conclusions

RV dysfunction with reduced end-systole RV WT could be a late phenotype in long-standing CIH and possibly also in obstructive sleep apnea.

EphrinB1 promotes cancer cell migration and invasion through the interaction with RhoGDI1

Eph receptors and their corresponding ephrin ligands have been associated with regulating cell–cell adhesion and motility, and thus have a critical role in various biological processes including tissue morphogenesis and homeostasis, as well as pathogenesis of several diseases. Aberrant regulation of Eph/ephrin signaling pathways is implicated in tumor progression of various human cancers. Here, we show that a Rho family GTPase regulator, Rho guanine nucleotide dissociation inhibitor 1 (RhoGDI1), can interact with ephrinB1, and this interaction is enhanced upon binding the extracellular domain of the cognate EphB2 receptor. Deletion mutagenesis revealed that amino acids 327–334 of the ephrinB1 intracellular domain are critical for the interaction with RhoGDI1. Stimulation with an EphB2 extracellular domain-Fc fusion protein (EphB2-Fc) induces RhoA activation and enhances the motility as well as invasiveness of wild-type ephrinB1-expressing cells. These Eph-Fc-induced effects were markedly diminished in cells expressing the mutant ephrinB1 construct (Δ327–334) that is ineffective at interacting with RhoGDI1. Furthermore, ephrinB1 depletion by siRNA suppresses EphB2-Fc-induced RhoA activation, and reduces motility and invasiveness of the SW480 and Hs578T human cancer cell lines. Our study connects the interaction between RhoGDI1 and ephrinB1 to the promotion of cancer cell behavior associated with tumor progression. This interaction may represent a therapeutic target in cancers that express ephrinB1.

Randomized controlled trial of steroid-soaked absorbable calcium alginate nasal packing following endoscopic sinus surgery

OBJECTIVES/HYPOTHESIS

To evaluate the potential efficacy of steroid-soaked, absorbable calcium alginate nasal packing following endoscopic sinus surgery.

STUDY DESIGN

Prospective, randomized, single-blinded, placebo-controlled trial.

METHODS

Twenty-two patients (44 nostrils) who had chronic rhinosinusitis with polyps underwent bilateral endoscopic sinus surgery. Only those with an intersinus difference in Lund-Mackay severity score of 1 or less were included. In each patient, one randomly selected nostril was packed with calcium alginate soaked with 2 mL of triamcinolone (40 mg/mL) (triamcinolone group), whereas the contralateral nostril received an identical packing soaked in 2 mL of normal saline (saline group). Two independent investigators blinded to the packing allocation scored the surgical field using the validated Perioperative Sinus Endoscopy (POSE) scores 1, 4, and 8 weeks after surgery.

RESULTS

All 44 nostrils were analyzed; the Lund-Mackay scores did not differ significantly between the groups before surgery. Eight weeks after surgery, the total POSE scores were significantly lower in the triamcinolone group (P = .014). The POSE scoring parameters were then compared between groups, and the following variables were significantly different: middle turbinate synechiae with the lateral wall (P = .037), polypoid degeneration of the ethmoid cavity (P = .006), and sphenoid sinus severity (P = .036).

CONCLUSIONS

This study demonstrated that steroid-soaked, absorbable nasal packing can be used to enhance wound healing after endoscopic sinus surgery and to prevent polypoid changes in the nasal mucosa.

LEVEL OF EVIDENCE

1b. Laryngoscope, 128:311-316, 2018.

Acute endophthalmitis after cataract surgery: 164 consecutive cases treated at a referral center in South Korea

PurposeTo identify prognostic factors in patients referred with endophthalmitis after cataract surgery, and to evaluate the efficacy of primary vitrectomy as an initial management.MethodsOver an eight-year study period, we retrospectively reviewed the medical records of 164 patients who were referred with endophthalmitis following cataract surgery. Treatment generally conformed to standard guidelines, although primary vitrectomy was performed in several eyes with a visual acuity of hand motion or better, depending on the patient's status. Using multivariate analysis, we analyzed outcomes to determine the effect on final visual outcome.ResultsA final visual acuity of ≥20/40 was achieved in 92/164 (56.1%) cases after treatment. Bacterial cultures showed bacterial growth in 89/164 cases (54.3%). Among the various baseline characteristics, old age (P=0.028), poor visual acuity at presentation (P=0.004), gram-negative bacterial infection (P=0.030), and short time between cataract surgery and signs of endophthalmitis (P=0.021) were associated with poor visual outcome. The visual outcome showed no significant difference, in terms of initial treatment feature, between the primary vitrectomy with intraocular antibiotics injection (IOAI) and IOAI-only groups. However, reintervention was significantly less frequent in the primary vitrectomy group than in the IOAI group (12.5 and 32.7%, respectively; P=0.002).ConclusionOld age, poor visual acuity at presentation, type of cultured organism (gram-negative bacteria), and early onset of endophthalmitis after cataract surgery were significantly related to poor visual outcome after endophthalmitis treatment. Primary vitrectomy may decrease the need for reintervention to control infection, although the treatment showed no benefits with regard to visual outcome.

Synergistic mucus secretion by histamine and IL-4 through TMEM16A in airway epithelium

Histamine is an important mediator of allergic reactions, and mucus hypersecretion is a major allergic symptom. However, the direct effect of histamine on mucus secretion from airway mucosal epithelia has not been clearly demonstrated. TMEM16A is a Ca²⁺-activated chloride channel, and it is closely related to fluid secretion in airway mucosal epithelia. We investigated whether histamine directly induces fluid secretion from epithelial cells or submucosal glands (SMG) and mechanisms related, therewith, in allergic airway diseases. In pig airway tissues from the nose or trachea, histamine was a potent secretagogue that directly induced strong responses. However, gland secretion from human nasal tissue was not induced by histamine, even in allergic rhinitis patients. Histamine type 1 receptor (H1R) and histamine type 2 receptor (H2R) were not noted in SMG by in situ hybridization. Cultured primary human nasal epithelial (NHE) cells were used for the measurement of short-circuit current changes with the Ussing chamber. Histamine-induced slight responses of anion secretions under normal conditions. The response was enhanced by IL-4 stimulation through TMEM16A, which might be related to fluid hypersecretion in allergic rhinitis. Pretreatment with IL-4 augmented the histamine response that was suppressed by a TMEM16A inhibitor. TMEM16A expression was enhanced by 24-h treatment of IL-4 in human nasal epithelial cells. The expression of TMEM16A was significantly elevated in an allergic rhinitis group, compared with a control group. We elucidated histamine-induced fluid secretions in synergy with IL-4 through TMEM16A in the human airway epithelium. In addition, we observed species differences between pigs and humans in terms of gland secretion of histamine.

Clinical implications of serum galactomannan measurement in patients with acute invasive fungal rhinosinusitis

BACKGROUND

Acute invasive fungal rhinosinusitis (AIFR) is an aggressive opportunistic infection with a high mortality rate. Recently, non-invasive techniques have been introduced for diagnosis of invasive fungal disease. The purpose of this study is to evaluate the diagnostic significance of serum galactomannan measurement in patients with AIFR.

METHODOLOGY

We conducted a retrospective case-control study of 28 patients with AIFR and 36 fungus ball (FB) patients. We evaluated clinical, laboratory, and pathologic findings along with disease course.

RESULTS

In 28 patients with AIFR, there were 21 cases of invasive aspergillosis (IA) and 7 cases of invasive mucormycosis (IM). The control group was comprised of 36 patients with FB. The three-group analysis showed a statistically significant difference among the groups. At the cut-off value of 0.48, the sensitivity and specificity were 71.4% and 93.0%, respectively. Comparison of mean serum galactomannan levels in 5 non-survivors and 9 survivors at initial measurement showed no significant difference, but that became significantly different 1 week later. Statistical analysis showed that the levels of serum galactomannan decreased significantly according to the measurement-point in within survivor-group analysis. The difference in between survivor-groups analysis was also significant.

CONCLUSION

Serum galactomannan measurement seems useful for early diagnosis and discrimination of fungal species in patients with AIFR. In addition, clinical outcomes may be related to the levels and patterns of serum galactomannan, especially in IA. The appropriate measurement of galactomannan might be helpful in treating the patients at high risk for AIFR.

T-helper 2 cytokine-induced heat shock protein 70 secretion and its potential association with allergic rhinitis

BACKGROUND

Various inflammatory mediators have been found to be involved in the pathogenesis of allergic disease (AR). The role of heat shock proteins in AR has not been studied. The aim of this study was to investigate the levels of heat shock protein 70 (Hsp70) in the nasal lavage fluids of AR patients and controls to elucidate the role of Hsp70 in the pathogenesis of AR.

METHODS

Using an enzyme-linked immunosorbent assay, the levels of Hsp70, Hsp90, interleukin (IL)-4, IL-13, and IL-8 in nasal lavage fluid from patients were measured and statistically analyzed. Primary human nasal epithelial cells were cultured in vitro and T-helper 2 (Th2) cytokines (IL-4, IL-13) were added to the culture medium. We evaluated the mRNA and protein expression levels of Hsp70 using real-time polymerase chain reaction and western blot assay.

RESULTS

Hsp70 was easily detected in nasal lavage fluid and the levels of Hsp70 were higher in AR patients than in healthy controls. Other clinical characteristics of subjects were not significantly associated with Hsp70 levels. Furthermore, we found that treatment with IL-4 and IL-13 induced the secretion of Hsp70 in human nasal epithelial cells.

CONCLUSION

We found that Hsp70 was abundant and positively detected in nasal lavage fluid samples from all subjects, and that Hsp70 levels were significantly higher in AR patients. We demonstrated, both in vivo and in vitro, that Hsp70 could play an important role in the pathogenesis of AR, and we suggest that Hsp70 can be used as a disease marker for AR.

Clinical implications of serum galactomannan measurement in patients with acute invasive fungal rhinosinusitis

BACKGROUND

Acute invasive fungal rhinosinusitis (AIFR) is an aggressive opportunistic infection with a high mortality rate. Recently, non-invasive techniques have been introduced for diagnosis of invasive fungal disease. The purpose of this study is to evaluate the diagnostic significance of serum galactomannan measurement in patients with AIFR.

METHODOLOGY

We conducted a retrospective case-control study of 28 patients with AIFR and 36 fungus ball (FB) patients. We evaluated clinical, laboratory, and pathologic findings along with disease course.

RESULTS

In 28 patients with AIFR, there were 21 cases of invasive aspergillosis (IA) and 7 cases of invasive mucormycosis (IM). The control group was comprised of 36 patients with FB. The three-group analysis showed a statistically significant difference among the groups. At the cut-off value of 0.48, the sensitivity and specificity were 71.4% and 93.0%, respectively. Comparison of mean serum galactomannan levels in 5 non-survivors and 9 survivors at initial measurement showed no significant difference, but that became significantly different 1 week later. Statistical analysis showed that the levels of serum galactomannan decreased significantly according to the measurement-point in within survivor-group analysis. The difference in between survivor-groups analysis was also significant.

CONCLUSION

Serum galactomannan measurement seems useful for early diagnosis and discrimination of fungal species in patients with AIFR. In addition, clinical outcomes may be related to the levels and patterns of serum galactomannan, especially in IA. The appropriate measurement of galactomannan might be helpful in treating the patients at high risk for AIFR.

Role of surgical treatment for esthesioneuroblastomas: 31-Year experience at a single institution

OBJECTIVE

This study aimed to re-assess the outcomes of different surgical methods for esthesioneuroblastoma (ENB) in a single institution, with emphasis on changes in surgical treatment with regard to endoscopic approaches in patients with ENB.

SUBJECTS AND METHODS

We retrospectively reviewed the data of 35 patients with ENB treated over the last 31 years.

RESULTS

The 5-year overall and disease-free survival rates were 66.8% and 50.8%, respectively. Disease-free survival in the endoscopic surgery group was significantly higher compared to that of craniofacial surgery group (P = 0.035). In the endoscopic surgery group, nine of 10 patients did not exhibit local failure or regional recurrence over a mean followup period of 64.3 months, which was longer than the mean time to recurrence (22.0 months) observed in this study.

CONCLUSION

Given its significant survival outcomes and high rate of local control, endoscopic surgery could be preferred as a minimally invasive treatment with potentially low morbidity and possible oncological validity for the treatment of ENB.