The Role of Parotid Gland Invasion in Adenoid Cystic Carcinoma of the External Auditory Canal.

OBJECTIVE: This study aimed to investigate the significance of parotid gland invasion in predicting distant metastasis of adenoid cystic carcinoma in the external auditory canal. STUDY DESIGN: Single-institution retrospective cohort study. METHODS: A retrospective review of patients with adenoid cystic carcinoma of the external auditory canal who underwent surgery was performed. Information on patient demographics, parotid gland invasion, tumor stage, perineural invasion, lymphovascular invasion, and follow-up data were collected and analyzed. RESULTS: One hundred twenty-nine patients were identified for review. Parotid gland invasion was noted in 45 patients (34.9%). Parotid gland invasion was significantly associated with tumor stage, perineural invasion, distant metastasis, and postoperative adjuvant therapy. Distant metastasis was noted in 30 patients (23.3%). Multivariate Cox proportional hazards analysis identified parotid gland invasion as an independent risk factor for predicting distant metastasis. The 5-year distant metastasis-free survival rate was 83.6% for patients without parotid gland invasion and 61.8% for patients with parotid gland invasion (p = 0.010). CONCLUSIONS: The parotid gland invasion rate is relatively high in adenoid cystic carcinoma of the external auditory canal and is significantly related to tumor stage. Parotid gland invasion is associated with worse distant metastasis-free survival. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:419-425, 2024.

Whole-brain monosynaptic outputs and presynaptic inputs of GABAergic neurons in the vestibular nuclei complex of mice.

GABAergic neurons in the vestibular nuclei (VN) participate in multiple vital vestibular sensory processing allowing for the maintenance and rehabilitation of vestibular functions. However, although the important role of GABA in the central vestibular system has been widely reported, the underlying neural circuits between VN GABAergic neurons and other brain functional regions remain elusive, which limits the further study of the underlying mechanism. Hence, it is necessary to elucidate neural connectivity based on outputs and inputs of GABAergic neurons in the VN. This study employed a modified rabies virus retrograde tracing vector and cre-dependent adeno-associated viruses (AAVs) anterograde tracing vector, combined with a transgenic VGAT-IRES-Cre mice, to map the inputs and outputs of VN GABAergic neurons in the whole brain. We found that 51 discrete brain regions received projections from VN GABAergic neurons in the whole brain, and there were 77 upstream nuclei innervating GABAergic neurons in the VN. These nuclei were mainly located in four brain regions, including the medulla, pons, midbrain, and cerebellum. Among them, VN GABAergic neurons established neural circuits with some functional nuclei in the whole brain, especially regulating balance maintenance, emotion control, pain processing, sleep and circadian rhythm regulation, and fluid homeostasis. Therefore, this study deepens a comprehensive understanding of the whole-brain neural connectivity of VN, providing the neuroanatomical information for further research on the neural mechanism of the co-morbidities with vestibular dysfunction.

Evaluation of subclasses for T4-classified squamous cell carcinoma of the external auditory canal.

BACKGROUND: T4-classified squamous cell carcinoma (SCC) of external auditory canal (EAC) can potentially involve different anatomical structures, which could translate into different treatment strategies and survival outcomes within one classification. Our aim is to evaluate the clinical added value of T4-subclasses proposed by Lavieille and by Zanoletti. METHODS: Retrospective data, including patients with primary operated cT4-classified EAC SCC, was obtained from 12 international hospitals. We subclassified according to the T4-subclasses. The treatment strategies, disease-free survival (DFS) and overall survival per subclass were calculated. RESULTS: A total of 130 T4-classified EAC SCC were included. We found commonly used treatment strategies per subclass according to Lavieille and the DFS seems also to differ per subclass. Subclass according to Zanoletti showed comparable treatment strategies and survival outcomes per subclass. CONCLUSION: Our study suggests that the subclass according Lavieille might have added value in clinical practice to improve care of T4-classified EAC SCC.

Gut Microbiome and Metabolome Changes in Mice With Acute Vestibular Deficit.

Vestibular deficit is a very common disorder in clinical practice and is characterized by vertigo, spontaneous nystagmus, and autonomic nervous symptoms, including nausea, vomiting, and sweating. In addition, the comorbidity of vestibular deficit and anxiety has long been an integral component of the medical literature. Previous studies have suggested that the mechanisms underlying this comorbidity involved overlap of vestibular and cerebellar networks. Emerging evidence has shown that the microbiota-gut-brain axis plays a key role in the regulation of affective disorders. Thus, we hypothesized that the gut microbiota may be involved in the comorbidity of vestibular deficit and anxiety. To verify this, we constructed a unilateral labyrinthectomy mouse model to simulate vestibular deficit. Then, 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) were used to analyze the microbiome and metabolome of the cecal samples collected from mice in the unilateral labyrinthectomy, sham surgery, and control groups. Notably, unilateral labyrinthectomy shaped the composition of the mouse gut microbiome, resulting in increased abundance of Lachnospiraceae NK4A136 group, Odoribacter and Roseburia and decreased abundance of Prevotella and Parasutterella at the genus level. Tax4Fun functional prediction indicated a decrease in tryptophan metabolism in mice in the unilateral labyrinthectomy group. Moreover, functional correlation of changes in gut microbes and metabolites between different groups showed that the oleamide level was negatively correlated with Odoribacter abundance (r = -0.89, p = 0.0002). The butyric acid level was positively correlated with Parasutterella abundance (r = 0.85, p = 0.0010). The propanoate level was negatively correlated with Prevotella abundance (r = -0.81, p = 0.0020). The 20-HETE level was positively correlated with Parasutterella abundance (r = 0.84, p = 0.0013). The altered microbes and metabolites were closely related to the pathogenesis of affective disorders. Our results not only offer novel insights into the vestibular deficit comorbid with anxiety but also build an important basis for future research on this etiology.

Prognostic value of pre-operative peripheral inflammation markers in patients with squamous cell carcinoma of the external auditory canal / Valor prognóstico dos marcadores de inflamação periférica pré-operatórios em pacientes com carcinoma espinocelular do meato acústico externo

Abstract Introduction: Squamous cell carcinoma of the external auditory canal is a rare entity. Previous studies have suggested predictors for tumor recurrence. However, most of the prognostic factors were from the clinicopathological aspect. Objective: This study aims to analyze the correlation between pre-operative peripheral inflammation markers and survival outcomes, in order to identify prognostic biomarkers for patients with squamous cell carcinoma of the external auditory canal. Methods: We retrospectively analyzed patients diagnosed with squamous cell carcinoma of the external auditory canal who underwent surgery at our institute. The pre-operative circulating inflammatory markers, such as the neutrophil, lymphocyte, platelet, and monocyte counts were measured and their ratios including neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and lymphocyte-to-monocyte ratio were calculated. The prognostic value of the measured hematologic parameters in relation to the survival outcomes was also evaluated. Results: A total of 83 patients were included, of which 26 patients showed tumor recurrence and 57 without recurrence. Neutrophil counts and neutrophil-to-lymphocyte ratio were closely connected with tumor stage. In the patients with recurrence, neutrophil counts, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio were elevated (p< 0.0001, p< 0.0001 and p = 0.001), while lymphocyte counts and lymphocyte-to-monocyte ratio were decreased (p = 0.013 and p = 0.016, respectively). The receiver operating curve analysis indicated that pre-operative neutrophil-to-lymphocyte ratio is a potential prognostic marker for recurrence of squamous cell carcinoma of the external auditory canal (area under curve = 0.816), and the cut-off points was 2.325. Conclusions: Pre-operative neutrophil and lymphocyte counts, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte are significantly correlated with tumor recurrence in patients with external auditory canal squamous cell carcinoma. Furthermore, neutrophil-to-lymphocyte ratio may be unfavorable prognostic factors of this disease.

Resumo Introdução: O carcinoma espinocelular do meato acústico externo é uma doença rara. Estudos anteriores sugeriram preditores de recorrência do tumor. Entretanto, a maioria dos fatores prognósticos se originou do aspecto clínico-patológico. Objetivo: Analisar a correlação entre marcadores inflamatórios periféricos pré-operatórios e os desfechos de sobrevida e identificar biomarcadores prognósticos para pacientes com carcinoma espinocelular do meato acústico externo. Método: Analisamos retrospectivamente pacientes com diagnóstico de carcinoma espinocelular do meato acústico externo submetidos à cirurgia em nosso instituto. Os marcadores inflamatórios circulantes pré-operatórios, como as contagens de neutrófilos, linfócitos, plaquetas e monócitos, foram medidos e as suas relações calculadas, inclusive as relações neutrófilos/linfócitos, plaquetas/linfócitos e linfócitos/monócitos. O valor prognóstico dos parâmetros hematológicos medidos em relação aos desfechos de sobrevida também foi avaliado. Resultados: Foram incluídos 83 pacientes, entre os quais 26 apresentaram recorrência tumoral e 57 não apresentaram. A contagem de neutrófilos e a relação neutrófilo/linfócito estavam intimamente associadas ao estágio do tumor. Nos pacientes com recorrência, a contagem de neutrófilos, a relação neutrófilos/linfócitos e a relação plaquetas/linfócitos eram elevadas (p < 0,0001, p > 0,0001 e p = 0,001), enquanto a contagem de linfócitos e a relação linfócitos/monócitos estavam diminuídas (p = 0,012 ep = 0,016, respectivamente). A análise da curva, Receiver Operating Characteristic, indicou que a relação neutrófilos/linfócitos pré-operatória era um potencial marcador prognóstico para a recorrência de carcinoma espinocelular do meato acústico externo (Área sob a curva = 0,816) e o ponto de corte foi de 2,325. Conclusão: A contagem pré-operatória de neutrófilos e linfócitos, as relações neutrófilos/linfócitos, plaquetas/linfócitos e linfócitos/monócitos estão significativamente correlacionadas com a recorrência do tumor em pacientes com carcinoma espinocelular do meato acústico externo. Além disso, a relação neutrófilos/linfócitos pode ser um fator prognóstico desfavorável dessa doença.

Prognostic value of pre-operative peripheral inflammation markers in patients with squamous cell carcinoma of the external auditory canal.

INTRODUCTION: Squamous cell carcinoma of the external auditory canal is a rare entity. Previous studies have suggested predictors for tumor recurrence. However, most of the prognostic factors were from the clinicopathological aspect. OBJECTIVE: This study aims to analyze the correlation between pre-operative peripheral inflammation markers and survival outcomes, in order to identify prognostic biomarkers for patients with squamous cell carcinoma of the external auditory canal. METHODS: We retrospectively analyzed patients diagnosed with squamous cell carcinoma of the external auditory canal who underwent surgery at our institute. The pre-operative circulating inflammatory markers, such as the neutrophil, lymphocyte, platelet, and monocyte counts were measured and their ratios including neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and lymphocyte-to-monocyte ratio were calculated. The prognostic value of the measured hematologic parameters in relation to the survival outcomes was also evaluated. RESULTS: A total of 83 patients were included, of which 26 patients showed tumor recurrence and 57 without recurrence. Neutrophil counts and neutrophil-to-lymphocyte ratio were closely connected with tumor stage. In the patients with recurrence, neutrophil counts, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio were elevated (p < 0.0001, p < 0.0001 and p = 0.001), while lymphocyte counts and lymphocyte-to-monocyte ratio were decreased (p = 0.013 and p = 0.016, respectively). The receiver operating curve analysis indicated that pre-operative neutrophil-to-lymphocyte ratio is a potential prognostic marker for recurrence of squamous cell carcinoma of the external auditory canal (area under curve = 0.816), and the cut-off points was 2.325. CONCLUSIONS: Pre-operative neutrophil and lymphocyte counts, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte are significantly correlated with tumor recurrence in patients with external auditory canal squamous cell carcinoma. Furthermore, neutrophil-to-lymphocyte ratio may be unfavorable prognostic factors of this disease.

Whole-brain monosynaptic inputs and outputs of glutamatergic neurons of the vestibular nuclei complex in mice.

Vestibular nuclei complex (VN) glutamatergic neurons play a critical role in the multisensory and multimodal processing. The dysfunction of VN leads to a series of vestibular concurrent symptoms, such as disequilibrium, spatial disorientation, autonomic disorders and even emotion disorders. However, the reciprocal neural connectivity in the whole brain of VN glutamatergic neurons was incompletely understood. Here, we employed a cell-type-specific, cre-dependent, modified virus vector to retrogradely and anterogradely trace VN glutamatergic neurons in the VGLUT2-IRES-Cre mouse line. We identified and analyzed statistically the afferents and efferents of VN glutamatergic neurons in the whole brain, and also reconstructed monosynaptic inputs distribution of VN glutamatergic neurons at the three-dimensional level with the combination of a fluorescence micro-optical sectioning tomography system (fMOST). We found that VN glutamatergic neurons primarily received afferents from 57 nuclei and send efferents to 59 nuclei in the whole brain, intensively located in the brainstem and cerebellum. Projections from nuclei in the cerebellum targeting VN glutamatergic neurons mainly performed the balance control - the principal function of the vestibular system. In addition, VN glutamatergic neurons sent projections to oculomotor nucleus, trochlear nucleus and abducens nucleus dominating the eye movement. Except for the maintenance of balance, VN glutamatergic neurons were also directly connected with other functional regions, such as sleep-wake state (locus coeruleus, dorsal raphe nucleus, and laterodorsal tegmental nucleus, gigantocellular reticular nucleus, lateral paragigantocellular nucleus, periaqueductal gray, subcoeruleus nucleus, parvicellular reticular nucleus, paramedian raphe nucleus), and emotional regulation (locus coeruleus and dorsal raphe nucleus). Hence, this study revealed a comprehensive whole-brain neural connectivity of VN glutamatergic neurons and provided with a neuroanatomic foundation to further study on central vestibular circuits.

Grading system and surgical approaches for endolymphatic sac tumors.

PURPOSE: Endolymphatic sac tumors (ELSTs) are rare, low-grade adenocarcinomas arising from the endolymphatic sac. This study aims to present a novel grading system for ELSTs to determine the optimal management strategy. METHODS: We performed a retrospective analysis of 16 patients with 17 ELSTs. The tumor location and involved adjacent neurovascular structures on CT and MRI were selected to establish the grading system. RESULTS: Based on the novel grading system, grade III a tumors were most common (7/17), followed by grade I (4/17), grade II (3/17), and grade III b (3/17) tumors. Eight advanced ELSTs (grade III a and III b) received an infra-temporal fossa approach, while the other 6 early stage ELSTs (grade I and II) underwent either a retrolabyrinthine approach with posterior petrosectomy or a translabyrinthine approach combined with subtotal temporal bone resection. Hearing preservation was achieved in 2 grade I patients. Postoperative facial nerve function was HB II in 1 grade III a patient who underwent anterior facial nerve transposition and was HB III in 4 advanced patients who received facial nerve grafts with the great auricular nerve or facial-hypoglossal nerve anastomosis. The mean follow-up time was 35.1 months. Two grade III patients and 1 grade II patient had tumor recurrence during follow-up, among whom 1 grade III b patient had two cases of recurrence. CONCLUSION: A correct initial diagnosis was established in all patients after meticulous imaging studies. Surgical resection is still the first choice to manage patients with ELSTs. The novel grading system enables surgeons to select tailored surgical approaches. Long-term follow-up is necessary following surgical intervention.

Adeno-associated virus transformation into the normal miniature pig and the normal guinea pigs cochlea via scala tympani.

OBJECTIVE: To investigate the expression of the miniature pig cochlea after AAV1 transfect into the cochlea via round window membrane (RWM). METHODS: Twenty miniature pigs are equally divided into four experimental groups. Twelve miniature pigs are equally divided into four control groups. Each pig was transfected with the AAV1 in the experimental group via RWM and each pig was transduced with the artificial perilymph in the control group. The expression of green fluorescent protein (GFP) was observed at 2 weeks, 3 weeks and 4 weeks, respectively. Likewise, AAV1 was delivered into the guinea pigs cochleas using the same method, and the results were compared with that of the miniature pigs. RESULTS: The expression was mainly in the inner hair cells of the miniature pig. The expression of GFP began to appear at 2 weeks, reached the peak at 3 weeks. It also expressed in Hensen's cells, inner pillar cells, outer pillar cells, spiral limbus, and spiral ligament. In the meanwhile, AAV1 was delivered into guinea pig cochlea via the same method, and AAV1 was also expressed in the inner hair cells. But the expression peaked at 2 weeks, and the efficiency of the inner hair cell transfection was higher than that of the pig. CONCLUSION: AAV1 can be transformed into miniature pig cochlea via scala tympani by the RWM method efficiently.