Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review.

Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.

Tympanic-mastoid and parotid schwannomas of the facial nerve: clinical presentation related to the anatomic site of origin.

Objective: To describe the clinical presentation of the facial nerve schwannomas according to the anatomical site of origin. Method: A retrospective study in which the clinical presentation, diagnostic protocol and treatment of facial nerve tumors in adults was evaluated. Results: We found 6 cases, 4 cases of tympanic-mastoid location at the spectrum of its possible clinical presentation: from symptomatic cases with facial paralysis, to an asymptomatic case in the tympanic portion found as intraoperative finding; and also found two cases located at the parotid gland, one with complete facial paralysis and one without facial palsy. Conclusions: For the diagnosis of intratemporal and parotid schwannomas of the facial nerve, a high clinical suspicion is required given its heterogeneous presentation; its clinical course depends on the segment of origin and expansion: more frequently asymptomatic at the tympanic horizontal portion and symptomatic at the mastoid vertical portion. These tumors must be assessed with imaging studies, incisional biopsy is not recommended. The treatment is surgical resection in symptomatic patients with facial paralysis greater than grade III of House-Brackmann, with immediate reconstruction of the nerve.

Objetivo: Describir la presentación clínica de los schwannomas del nervio facial de acuerdo con el sitio anatómico de origen. Método: Se realizó un estudio retrospectivo en el que se evaluó la presentación clínica, el protocolo diagnóstico y el tratamiento de tumores del nervio facial en adultos. Resultados: Se encontraron seis casos, cuatro de ellos de localización tímpano-mastoidea en los extremos de su posible presentación clínica: desde casos sintomáticos con parálisis facial, hasta un caso asintomático de la porción timpánica encontrado como hallazgo transoperatorio; y se encontraron dos casos de localización parotídea, uno con parálisis facial completa y otro sin parálisis facial. Conclusiones: Para el diagnóstico de tumores intratemporales y parotídeos del nervio facial se requiere una elevada sospecha clínica dado lo heterogéneo de su presentación; su curso clínico depende del segmento de origen y de su extensión: más frecuentemente son asintomáticos los de la porción timpánica y son sintomáticos los de la porción mastoidea. Estos tumores deben evaluarse con estudios de imagen; no se recomienda realizar biopsia incisional. El tratamiento es la resección quirúrgica en los casos sintomáticos con parálisis facial de grado IV o mayor de House-Brackmann, con reconstrucción inmediata del nervio.

Association between facial nerve second genu angle and facial canal dehiscence in patients with cholesteatoma: evaluation with temporal multidetector computed tomography and surgical findings / Associação entre o ângulo do segundo joelho do nervo facial e deiscência do canal facial em pacientes com colesteatoma: avaliac¸ão do osso temporal por tomografia com multidetectores e pelos achados cirúrgicos

Abstract Introduction: Otitis media, mastoiditis or the pressure effect of tumorous lesions such as cholesteatoma can be the cause of facial canal dehiscence and facial nerve paralysis. The most common segment involved in dehiscence is the tympanic segment and the second most common is the lateral aspect of the facial canal in the oval window area. Objective: To determine the prevalence of the facial canal dehiscence and the relationship between the angle at the second genu of the facial nerve and facial canal dehiscence. Methods: We evaluated the surgical findings in 113 patients who underwent surgery for cholesteatoma. Facial canal dehiscence was detected in 62 of the 113 patients. Patients were divided into two groups: Group 1, with dehiscence of the facial canal and Group 2, without dehiscence of the facial canal. Results: The mean angles at the second genu of the facial nerve in Groups 1 and 2 were 117.8º ± 9.63º and 114º ± 9.9º, respectively. There was a statistically significant difference between the mean angles at the second genu for the two groups (p = 0.04). Conclusion: In patients with dehiscence of the facial canal, the angle at the second genu was found to be wider than those without dehiscence.

Resumo Introdução: Otite média, mastoidite ou a compressão por lesões tumorais como o colesteatoma podem ser a causa da deiscência do canal facial e paralisia do nervo facial. A deiscência ocorre mais frequentemente no segmento timpânico, seguido do aspecto lateral do canal facial na área da janela oval. Objetivo: Determinar a prevalência da deiscência do canal facial e sua relação com o ângulo no segundo joelho do nervo facial. Método: Avaliamos os achados cirúrgicos para detecção de deiscência do canal facial em 113 pacientes submetidos à cirurgia de colesteatoma. A deiscência do canal facial foi observada em 62. Os pacientes foram divididos em dois grupos: Grupo 1, com deiscência do canal facial, e Grupo 2, sem deiscência do canal facial. Resultados: Os ângulos médios no segundo joelho do nervo facial nos grupos 1 e 2 foram 117,8º ± 9,63º e 114º ± 9,9º, respectivamente. Houve diferença estatisticamente significante entre os ângulos médios no segundo joelho para os dois grupos (p = 0,04). Conclusão: Em pacientes com deiscência no canal facial, foi observado que o ângulo do segundo joelho era maior do que naqueles sem deiscência.

Association between facial nerve second genu angle and facial canal dehiscence in patients with cholesteatoma: evaluation with temporal multidetector computed tomography and surgical findings.

INTRODUCTION: Otitis media, mastoiditis or the pressure effect of tumorous lesions such as cholesteatoma can be the cause of facial canal dehiscence and facial nerve paralysis. The most common segment involved in dehiscence is the tympanic segment and the second most common is the lateral aspect of the facial canal in the oval window area. OBJECTIVE: To determine the prevalence of the facial canal dehiscence and the relationship between the angle at the second genu of the facial nerve and facial canal dehiscence. METHODS: We evaluated the surgical findings in 113 patients who underwent surgery for cholesteatoma. Facial canal dehiscence was detected in 62 of the 113 patients. Patients were divided into two groups: Group 1, with dehiscence of the facial canal and Group 2, without dehiscence of the facial canal. RESULTS: The mean angles at the second genu of the facial nerve in Groups 1 and 2 were 117.8°±9.63° and 114°±9.9°, respectively. There was a statistically significant difference between the mean angles at the second genu for the two groups (p=0.04). CONCLUSION: In patients with dehiscence of the facial canal, the angle at the second genu was found to be wider than those without dehiscence.

Hearing loss in peripheral facial palsy after decompression surgery.

UNLABELLED: Facial paralysis can result from a variety of etiologies; the most common is the idiopathic type. Evaluation and treatment are particularly complex. The treatment of acute facial paralysis may require facial nerve decompression surgery. Any structure near the path of the facial nerve is at risk during transmastoid decompression surgery. AIM: This is a retrospective study, carried out in order to evaluate hearing loss after transmastoid decompression and how idiopathic cases evolved in terms of their degree of paralysis in the last 15 years. MATERIALS AND METHODS: We selected the charts from 33 patients submitted to transmastoid facial nerve decompression in the past 15 years and we assessed their hearing loss and facial paralysis. RESULTS: There was a high percentage (61%) of patients with some degree of hearing loss after the procedure and in all cases there was improvement in the paralysis. DISCUSSION: The values obtained are similar to those reported in the literature. One possible explanation for this hearing loss is the vibration transmission by drilling near the ossicular chain. CONCLUSION: The surgical procedure is not risk free; indications, risks and benefits should be explained to patients through an informed consent form.

Perdas auditivas em paralisia facial periférica após cirurgia de descompressão / Hearing loss in peripheral facial palsy after decompression surgery

A paralisia facial pode resultar de uma variedade de etiologias, sendo a mais comum a idiopática. A avaliação e o tratamento são particularmente complexos. O tratamento da paralisia facial aguda pode envolver cirurgia de descompressão do nervo facial. Qualquer estrutura perto do trajeto do nervo facial está em risco durante a cirurgia de descompressão via transmastoidea. OBJETIVO: Estudo retrospectivo que irá avaliar a perda auditiva após descompressão via transmastoidea e a evolução do grau de paralisia nos casos idiopáticos dos últimos 15 anos. MATERIAL E MÉTODO: Foram selecionados prontuários de 33 pacientes submetidos à descompressão do nervo facial via transmastoidea nos últimos 15 anos e avaliou-se a perda auditiva e a paralisia facial. RESULTADOS: Observou-se alta porcentagem (61%) dos pacientes com algum grau de perda auditiva após o procedimento e, em todos os casos, houve melhora da paralisia. CONCLUSÃO: O procedimento cirúrgico não é isento de riscos. Indicações, riscos e benefícios devem ser esclarecidos aos pacientes por meio de consentimento informado.

Facial paralysis can result from a variety of etiologies; the most common is the idiopathic type. Evaluation and treatment are particularly complex. The treatment of acute facial paralysis may require facial nerve decompression surgery. Any structure near the path of the facial nerve is at risk during transmastoid decompression surgery. AIM: This is a retrospective study, carried out in order to evaluate hearing loss after transmastoid decompression and how idiopathic cases evolved in terms of their degree of paralysis in the last 15 years. MATERIALS AND METHODS: We selected the charts from 33 patients submitted to transmastoid facial nerve decompression in the past 15 years and we assessed their hearing loss and facial paralysis. RESULTS: There was a high percentage (61%) of patients with some degree of hearing loss after the procedure and in all cases there was improvement in the paralysis. DISCUSSION: The values obtained are similar to those reported in the literature. One possible explanation for this hearing loss is the vibration transmission by drilling near the ossicular chain. CONCLUSION: The surgical procedure is not risk free; indications, risks and benefits should be explained to patients through an informed consent form.

Estudo anatômico do pedículo vásculo-nervoso do retalho do ventre anterior do músculo digástrico / Anatomic study of the anterior belly of the digastric muscle flap neurovascular pedicle

Introdução: A paralisia facial é uma síndrome com implicações estéticas e funcionais importantes.A reanimação do segmento facial afetado pode ser realizada por diversas técnicas. Atransposição de músculos regionais inervados por outro nervo craniano não afetado é um dosmétodos utilizados com frequência. O ventre anterior do músculo digástrico, inervado pelonervo miloioideo, ramo do nervo trigêmio, é um retalho bastante usado para a reanimação dadepressão do lábio inferior. Uma maior mobilidade deste retalho poderia permitir a transposiçãodo músculo para outros segmentos da face, ampliando sua utilização na prática clínica.Método: Estudamos o pedículo vásculo-nervoso do ventre anterior do músculo digástricoem 10 cadáveres, a fim de determinar o arco de rotação do seu retalho mantendo intacto oseu nervo aferente, e estudamos os diâmetros da artéria submentoniana, responsável pelo seusuprimento sanguíneo, com o objetivo de determinar a viabilidade de eventual reanastomosemicrocirúrgica. Resultados: Encontramos um arco de rotação médio de 3,71 cm a partirda borda inferior da mandíbula. O diâmetro externo da artéria submentoniana mediu emmédia 1,05 mm, o que permitiria a anastomose microcirúrgica a outro tronco arterial daface, dando uma maior liberdade para a mobilização do retalho. Conclusão: O retalho assimmobilizado tem, portanto, potencial renovado para uso na reanimação da paralisia facial.

Introduction: Fascial palsy is a syndrome with important esthetical and functional implications.The reanimation of the affected segment of the face can be obtained with severaltechniques. The transposition of local muscles, innervated by other cranial nerves, is frequentlyused. The anterior belly of the digastric muscle flap, innervated by the milohyoidnerve, a branch of the trigeminal nerve, is commonly used to treat the denervation of theinferior lip depressor muscle. A greater mobilization of this flap could allow its transpositionto other fascial segments. Methods: We have studied the vascular and nervous pedicle ofthe anterior belly of the digastric muscle in 10 unfixed cadavers, to determine the rotationarch of the flap, keeping its nerve intact. We have also studied the diameters of the submentonianartery, responsible for the blood suply to the flap, in order to evaluate the possibilityof microsurgical anastomosis to other vascular branches. Results: We have found a medianarch of rotation of 3.71 cm from the inferior border of the mandibule. The median externaldiameter of the artery was 1.05 mm, allowing its revascularization with microsurgicaltechnique. Conclusion: This mobilization of the anterior belly of the digastric muscle flapshows a potential for further use in the reanimation of fascial palsy.

[Intrapretosal schwannomas of facial nerve]. / Schwannomas intrapetrosos del nervio facial.

The aim of this study was to determine the factors that are important to the diagnosis and treatment of facial neuroma. The most common tumors of the peripheral nerves are the neurinomas; about 50% of them are found in the head and neck region. Among them, the most frequent is the VIII nerve tumor, while the facial neuroma is extremely rare. Neuromas can be intracraneal, intratemporal and extratemporal. The last one has a higher frequency. We present our experience in the intrapetrosal facial neuromas; usually showing different presentation symptoms wich is a characteristic of them. Retrospective study that was carried out at a private tertiary referral center. 3 patients were referred from other centers for otological surgery. One of them had symptoms of chronic otitis media, the second one was diagnosed of a glomus tumor and the last one showed a facial palsy. All the patients were operated on and then the facial nerve was repaired. Two patients had an end to end anastomosis, and in the other one we managed to keep the integrity of the facial nerve. The Hous -Brackmann facial grading scale was used. Two patients had grade II and the other grade III in this scale in the long-term follow up.

Facial nerve neurinoma in a child.

Facial nerve neurinoma is a benign tumor, infrequent and exceptional in children. It's clinical manifestation depends on its location and extension, facial palsy being its most frequent sign. Complementary examinations, namely image-diagnosis studies and audiometric tests become essential. Certain diagnosis is made by pathological anatomy. The reported case is a 13-year-old patient suffering from left peripheral facial palsy with an evolution of 8 months who went through a middle cerebral fossa and transmastoid combined tract.

Anastomosis of the intratemporal facial nerve using fibrin tissue adhesive.

This work aimed at studying the results obtained by the repair of complete lesions of the facial nerve in its intratemporal portions. Clinical, electrophysiological and surgical techniques were studied. Twenty-three patients with traumatic facial nerve lesions were operated. Nerve grafts were made in 10, and end-to-end anastomosis in thirteen. The surgical technique performed was the coaptation of the stumps and stabilization with fibrin tissue adhesive. Sixteen months after surgery, a clinical and electrophysiological evaluation was made. The use of fibrin tissue adhesive to stabilize intratemporal anastomosis of facial nerve showed clinical and electrophysiological evidence of axonal growth and reinnervation of mimical muscles of the face. These results were similar to that obtained by other authors that used other methods of microanastomosis. The use of fibrin tissue adhesive is an effective technique to utilize in intratemporal anastomosis of the facial nerve.

Neuroma intratemporal do nervo facial / Intratemporal neuroma of facial nerve

O neuroma do Nervo Facial é um tumor de baixa incidência e considerado de diagnóstico pouco freqüente. O diagnóstico é baseado na história clínica e em exames neuroradiológicos. Na maioria dos casos os pacientes apresentam-se com paralisia facial, mas alguns apresentam-se com perda auditiva e funçäo normal do Nervo Facial, o que torna o diagnóstico mais difícil. O tratamentoconsiste na completa excisäo do tumor. As opçöes para a restauraçäo das funçöes do Nervo Facial säo: anastomose términino-terminal, enxêrto autógeno de nervo, anastomose Hipolglosso-Facial, transposiçäo, tranposiçäo de Músculo Temporal ou transplante de músculos. Neste relato apresentaremos 5 caso diagnosticados no nosso serviço no período de 1985 a 1990. Todos os casos foram submetidos a tratamento cirúrgico, sendo em 4 empregado enxerto autógeno do Nervo Grande Auricular, e em um paciente "cross-face" com transferência de Músculo Gracilis