Application of cochlear nerve action potential monitoring in the resection of vestibular schwannomas / 中华耳鼻咽喉头颈外科杂志

Objective: To investigate the application of cochlear nerve action potential (CNAP) monitoring in the resection of vestibular schwannoma, especially evaluating its significance for hearing preservation. Methods: From April 2018 to December 2021, 54 patients with vestibular schwannoma who underwent resection via retrosigmoid approach were collected in Chinese PLA General Hospital. Before surgery, all patients had effective hearing (AAO-HNS grade C or above). Brainstem auditory evoked potential (BAEP) combined with CNAP monitoring was performed during surgery. The CNAP monitoring was combined with continuous monitoring and cochlear nerve mapping. And patients were divided into hearing preservation group and non-preserved group according to postoperative AAO-HNS grade. SPSS 23.0 software was used to analyze the differences of CNAP and BEAP parameters between the two groups. Results: A total of 54 patients completed intraoperative monitoring and data collection, including 25 males (46.3%) and 29 females (53.7%), aged 27-71 years with an average age of 46.2 years. The maximum tumor diameter were (18.1±5.9) mm (range 10-34 mm). All tumors were totally removed with preserved facial nerve function (House-Brackmann grade I-II). The hearing preservation rate of 54 patients was 51.9% (28/54). During surgery, the V wave extraction rate of BAEP waveform was 85.2% (46/54) before tumor resection, 71.4% (20/28) in the hearing preservation group after tumor resection, and disappeared in the hearing preservation group (0/26). CNAP waveform was elicited in 54 patients during operation. Differences were found in the distribution of CNAP waveforms after tumor resection. The waveforms of the hearing-preserving group were triphasic and biphasic, while those in the non-preserving group were low-level and positive. For hearing preservation group, the amplitude of N1 wave after tumor resection was significantly higher than that before tumor resection[14.45(7.54, 33.85)μV vs 9.13(4.88, 23.35)μV, P=0.022]; However, for the non-preserved group, the amplitude of N1 wave after tumor resection was significantly lower than that before tumor resection [3.07(1.96, 4.60)μV vs 6.55(4.54, 9.71)μV, P=0.007]; After tumor resection, the amplitude was significantly higher than that of the unreserved group [14.45(7.54, 33.85)μV vs 3.07(1.96, 4.60)μV, P<0.001]. Conclusions: BAEP combined with CNAP monitoring is conducive to intraoperative hearing protection, and the application of cochlear nerve mapping can prompt the surgeon to avoid nerve injury. The waveform and N1 amplitude of CNAP after tumor resection have a certain value in predicting postoperative hearing preservation status.

Schwanoma gigante do VIII nervo craniano de evolução subaguda: relato de caso / Subacute evolution of giant schwannoma of VIII cranial nerve: case report

O schwanoma vestibular é uma neoplasia que se origina das células de Schwann da porção vestibular do VIII nervo craniano e que corres- ponde a cerca de 10% dos tumores intracranianos e a 80% a 90% daqueles localizados no ângulo pontocerebelar. Apesar do crescimento lento e evolução em geral benigna, estes tumores podem evoluir de maneira desfavorável devido à localização em compartimento anatômico relativamente reduzido no crânio (fossa posterior), o que pode levar a compressão de estruturas nobres (como o tronco encefálico) e a desenvolvimento de hidrocefalia obstrutiva, especialmente nos raros casos de schawanomas gigantes (> 40 mm). Apresentamos relato de caso de paciente com quadro de tinnitus e hipoacusia à esquerda que evoluiu de forma subaguda com alterações do humor, da cognição e da marcha cujo diagnóstico final foi de schwanoma gigante do VIII nervo craniano.

Vestibular schwannoma is a Schwann cells neoplasia of the vestibular branch of the VIII cranial nerve and it accounts for 10% of intracranial tumours and to 80%-90% of those located at the cerebellopontine angle. Despite slow growth and usual benign evolution, unfavourable outcomes may occur, especially in the rare cases of giant schwanno- mas (> 40mm). Owing the fact that this tumours are located in a relatively narrow space (posterior fossa), giant schwannomas may compress noble areas (as the brainstem), which can also cause obstructive hydrocephalus. We discuss a case report of a 48 years old woman complaining of left-sided hearing loss and tinnitus that developed a subacute cognitive impairment, mood disorder and gait disturbance, diagnosed with giant schwannoma of the VIII nerve.

Surgical exposure of the internal auditory canal through the retrosigmoid approach with semicircular canals anatomical preservation / Avaliação da exposição do fundo do conduto auditivo interno através do acesso retrosigmóide-transmeatal

Objective Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS). Method Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures. Results The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity. Conclusion A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals. .

Objetivo Avaliar a possibilidade de exposição adequada preservando anatomia das estruturas labirínticas pelo acesso retrosigmóide-transmeatal (RSA) nas ressecções de schwannomas do vestibular (VS). Método Trinta pacientes foram submetidos à ressecção cirúrgica e avaliados no pré-operatório com tomografias de alta definição e reconstruções de ressonância magnética 3D. A extensão da abertura do conduto auditivo interno (CAI) foi medida e confirmada com parâmetros de neuronavegação. No pós-operatório, a extensão da abertura e a integridade do labirinto foram confirmadas por imagens de tomografia computadorizada. Resultados A extensão do CAI no pré-operatório apresentou variação de 7,8-12 mm (média 9,3 mm, DP 0,98, IC95% de 8,9-9,6 e mediana 9 mm). Imagens pós-operatórias demonstraram abertura adequada do IAC e integridade dos canais semicirculares. Conclusão A abertura completa da parede posterior do CAI pelo RSA é possível e permite a visualização direta do fundo do conduto sem prejudicar os canais semicirculares. .

The extracisternal approach in vestibular schwannoma surgery and facial nerve preservation / A abordagem extracisternal na cirurgia de schwannoma vestibular e preservação do nervo facial

The classical surgical technique for the resection of vestibular schwannomas (VS) has emphasized the microsurgical anatomy of cranial nerves. We believe that the focus on preservation of the arachnoid membrane may serve as a safe guide for tumor removal. Method The extracisternal approach is described in detail. We reviewed charts from 120 patients treated with this technique between 2006 and 2012. Surgical results were evaluated based on the extension of resection, tumor relapse, and facial nerve function. Results Overall gross total resection was achieved in 81% of the patients. The overall postoperative facial nerve function House-Brackmann grades I-II at one year was 93%. There was no recurrence in 4.2 years mean follow up. Conclusion The extracisternal technique differs from other surgical descriptions on the treatment of VS by not requiring the identification of the facial nerve, as long as we preserve the arachnoid envelope in the total circumference of the tumor. .

A técnica cirúrgica clássica para ressecção de schwannomas vestibulares enfatiza a anatomia microcirúrgica dos nervos cranianos. Acreditamos que o foco na preservação da membrana aracnóide pode servir como parâmetro seguro para a remoção do tumor. Método A abordagem extracisternal é descrita em detalhe. Analisamos o prontuário de 120 pacientes tratados com esta técnica entre 2006 e 2012. Os resultados cirúrgicos foram baseados em extensão de ressecção, recorrência tumoral e função do nervo facial. Resultados Ressecção total foi obtida em 81% dos pacientes. O resultado global da função do nervo facial (House-Brackmann graus I-II) após um ano da cirurgia foi de 93%. Não houve recidiva em um seguimento médio de 4,2 anos. Conclusão A técnica extracisternal difere de outras descrições cirúrgicas no tratamento de schwannoma vestibular pois não requer a identificação do nervo facial, contanto que o plano de aracnóide seja preservado em toda circunferência do tumor. .

Change in Tinnitus after Treatment of Vestibular Schwannoma: Microsurgery vs. Gamma Knife Radiosurgery

PURPOSE: Tinnitus is a very common symptom of vestibular schwannoma, present in 45 to 80% of patients. We evaluated changes in tinnitus after translabyrinthine microsurgery (TLM) or gamma knife radiosurgery (GKS). MATERIALS AND METHODS: Among 78 patients with vestibular schwannoma who underwent TLM or GKS at Severance Hospital from 2009-2012, 46 patients with pre- or postoperative tinnitus who agreed to participate were enrolled. Pure tone audiometry, tinnitus handicap inventory (THI), visual analogue scale (VAS) scores for loudness, awareness, and annoyance were measured before and after treatment. Changes of THI and VAS were analysed and compared according to treatment modality, tumour volume, and preoperative residual hearing. RESULTS: In the TLM group (n=27), vestibulocochlear nerves were definitely cut. There was a higher rate of tinnitus improvement in TLM group (52%) than GKS group (16%, p=0.016). The GKS group had a significantly higher rate of tinnitus worsening (74%) than TLM group (11%, p<0.001). Mean scores of THI and VAS scores significantly decreased in the TLM group in contrast to significant increases in the GKS group. Tumor volume and preoperative hearing did not affect the changes in THI or VAS. CONCLUSION: GKS can save vestibulocochlear nerve continuity but may damage the cochlea, cochlear nerve and can cause worsening tinnitus. In cases where hearing preservation is not intended, microsurgery with vestibulocochlear neurectomy during tumor removal can sometimes relieve or prevent tinnitus.

Long-term results of LINAC-based stereotactic radiosurgery for acoustic neuroma: the Greek experience.

PURPOSE: To estimate the value of LINAC-based stereotactic radiosurgery (SRS) for the long-term local control of unilateral acoustic neuromas. MATERIALS AND METHODS: Twenty patients (median age 66; range 57-80 years) with unilateral acoustic neuroma underwent LINAC-based SRS from May 2000 through June 2004 with a dose of 11-12 Gy. The follow-up period ranged from 36 to 84 months (median follow-up period: 55 months). Before SRS none of the patients had useful hearing. The follow-up consisted of repeat imaging studies and clinical examination for assessment of facial and trigeminal nerve function at 6-month intervals for the first year and yearly thereafter. RESULTS: Eleven tumors (58%) decreased in size and eight (42%) remained stable. One tumor showed a minor increase in size on the MRI done 6 months after SRS in comparison with the pretreatment MRI; however, a subsequent decrease was noticed on the next radiographic assessment and the tumor remained stable from then on. None of the tumors increased in size in the long-term follow-up, thus giving an overall growth control of 100% for the patients in this study. None of the patients had useful hearing before SRS, so hearing level was not assessed during follow-up. No patient developed new, permanent facial or trigeminal neuropathy. CONCLUSION: LINAC-based SRS with 11-12 Gy provides excellent tumor control in acoustic neuroma and has low toxicity even after long-term follow-up.

Tratamiento de schwanomas vestibulares esporádicos mediante radiocirugía: estudio prospectivo de cohorte / Radiosurgical treatment of sporadic vestibular schwannomas: a prospective cohort study

Objetivo: Analizar los resultados iniciales de un estudio prospectivo en pacientes con schwanomas vestibulares tratados con radiocirugía en la Pontificia Universidad Católica de Chile. Material y método: Se presentan 17 pacientes portadores de schwanomas vestibularesesporádicos tratados con radiocirugía y seguidos entre 6 y 26 meses. El tratamiento fue realizado con acelerador lineal Varian clinac 21 EX, con equipamiento Varian-Zmed. La dosismarginal administrada al tumor fue de 12 a 12,5 Gray. El seguimiento a 6, 12 y 24 meses consta de resonancia magnética, audiometría y evaluación clínica. Resultados: La dosis marginal de irradiación usada fue entre 12 y 12,5 Gray normalizada a la isodosis 70% u 80%. En todos los pacientes se documentó disminución de la captación de contraste del tumor y en 16 (94%) se observaron áreas de necrosis centro tumoral. No hubo mortalidad, la preservación de audición útil fue 62,5% actuarial a 2 años. No ha existido deterioro de la función de los nervios facial ni trigémino. Todos los pacientes que previamente estaban trabajando retornaron a sus labores en promedio 11,5 días luego del tratamiento. Conclusiones: Los resultados iniciales de esta serie son comparables a los resultados publicados en la literatura y refuerzan el demostrado rol de la radiocirugía en el tratamiento de los schwanomas vestibulares.

Objective: To analyze the preliminary experience of radiosurgery for VestibularSchwannomas at the Pontificia Universidad Católica de Chile. Material and methods: The first 17 patients with sporadic Vestibular Schwannomas treated by radiosurgery at our institution are reported. The marginal dose used was 12 to 12.5 Gy. prescribed at the 70 or 80 isodose line. Patients were controlled at 6, 12 and24 months with magnetic resonance, audiometric study and clinical examination. Results: In all of the 17 patients treated a decrease tumor enhancement on MR was demonstrated. In 16 patients (94%) a pattern of central tumor necrosis was observedduring the firs year. Actuarial useful hearing was maintained in 62.5% at 2 year after treatment. Facial nerve function was maintained in all of the 15 patients with normal function at treatment (100%). Trigeminal function was maintained in all of the 14 patients (100%) with previous normal trigeminal function. The mean time to return to work or normal activities was 11.5 days after treatment Conclusions: These preliminary results are comparable with results published in theliterature and reinforce the demonstrate role of radiosurgery in the management of vestibular schwannomas.

Long-term facial nerve clinical evaluation following vestibular schwannoma surgery / Avaliação clínica tardia do nervo facial no pós-operatório de schwannoma vestibular

BACKGROUND: Facial function is important in accompaniment of patients operated on vestibular schwannoma (VS). OBJETIVE: To evaluate long term facial nerve function in patients undergoing VS resection and to correlate tumor size and facial function in a long-term follow-up. METHOD: Transversal study of 20 patients with VS operated by the retrosigmoid approach. House-Brackmann Scale was used preoperatively, immediately after surgery and in a long-term follow-up. Student t test was applied for statistic analysis. RESULTS: In the immediate postoperative evaluation, 65 percent of patients presented FP of different grades. Improvement of facial nerve function (at least of one grade) occurred in 53 percent in the long-term follow-up. There was statistically significant difference in facial nerve outcome in long-term follow-up when tumor size was considered (p<0.05). Conclusion: The majority of patients had improvement of FP in a long-term follow-up and tumor size was detected to be a factor associated with the postoperative prognostic.

CONTEXTO: A função facial é importante para acompanhamento dos pacientes operados de schwannoma vestibular (SV). OBJETIVO: Avaliar o grau de paralisia facial (PF) em pacientes operados de SV, correlacionando tamanho do tumor com função facial na avaliação tardia. MÉTODO: Estudo transversal com análise seriada de 20 pacientes com SV operados pela via retrosigmóide-transmeatal. A Escala de House-Brackmann foi utilizada no pré-operatório, pós-operatório imediato e pós-operatório tardio. O teste t de Student foi aplicado para análise estatística. RESULTADOS: No pós-operatório imediato, 65 por cento dos pacientes apresentaram graus variados de PF, sendo que 53 por cento destes obtiveram melhora de pelo menos um grau de House-Brackmann na avaliação tardia. Houve diferença significativa no resultado da função facial no pós-operatório tardio quando o tamanho do tumor foi considerado (p<0.05).Conclusão: A maioria dos pacientes da amostra apresentou melhora da PF no pós-operatório tardio, sendo o tamanho do tumor um fator associado ao prognóstico.

Management of vestibular schwannomas: current state of the art

Vestibular schwannomas [VS] have always been a great challenge for neurosurgeons. The evolution of surgical management of VS is parallel of the history of the development of modem neurosurgery. Gamma knife surgery [GKS] is becoming a standard treatment for small or middle size VS while microsurgery remains the effective treatment of the large tumours. The combinations of the two techniques offer a big chance to preserve facial function in Koos IV VS. The Marseille SRS experience includes 2150 patients, with more than 1000 patients having follow-up longer than 3 years. In this series the Koos classification was: stage I 9%, stage II 55.5%, stage III 287 31% and stage IV 4.5%. The average volume was 12.7 mm[3]. Heating was useful [Gardner and Robertson] before radiosurgery in 47% of the patients [subnormal in 20.3%].A long-term tumour control rate of 97%. Globally, a clinical trigeminal injury was observed in 0.6% of the patients and transient facial palsy lower than 1%. There was clearly a decrease of the incidence of neuropathies with time, and a probability of functional hearing preservation between 50 and 95%, depending on preoperative parameters, was achieved in this large series of patients treated by state-of-the-art GKS. Other parameters such as long-term complications, type 2 neurofibromatosis, the influence of tumour characteristics and the treatment of the residual or recurrent VS after microsurgery are reviewed and detailed. Today, strong evidence supports the superiority of GKS in terms of functional preservation and equal efficacy compared with microsurgical removal. Consequently, radiosurgery must be preferred as a first intention choice for young patients with few symptoms presenting with a small to middle size VS [Koos I to Ill]. Only large Koos IV remained first line indication for microsurgery. The combined approach should provide these patients with a major reduction of risks, particularly in terms of rate of facial palsy

Acoustic neuroma (vestibular schwannoma): surgical results on 240 patients operated on dorsal decubitus position

OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99 percent of the cases, with a mortality of 1.6 percent. The facial nerve function was preserved in 85 percent of cases and hearing in 40 percent of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8 percent and meningitis 2.9 percent. Venous air embolism was registered in 3 percent of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

OBJETIVO: Avaliar o resultado do tratamento cirúrgico de pacientes portadores de schwannoma do vestibular (SV) operados em decúbito dorsal (posição de mastóide). MÉTODO: 240 pacientes foram submetidos a craniotomia retrosigmóide na posição de mastóide. A função do VII e VIII nervos cranianos foi monitorizada durante a cirurgia e a reconstrução da abertura do conduto auditivo interno foi realizada com retalho vascularizado de dura-mater, músculo e cola de fibrina. RESULTADOS: A exérese foi completa em 99 por cento dos casos, com mortalidade de 1,6 por cento. Houve preservação da função do nervo facial em 85 por cento dos casos e da audição em 40 por cento dos pacientes com audição prévia e tumores menores de 1,5 cm. A incidência de fístula liquórica foi 5,8 por cento e meningite 2,9 por cento. Embolia gasosa foi registrada em 3 por cento dos casos, não associada à mortalidade. CONCLUSÃO: O tratamento cirúrgico dos SV utilizando-se a posição de mastóide tem várias vantagens, com baixa morbidade e mortalidade.

Associação entre tamanho e potencial proliferativo em neurinomas do acústico / Size and proliferative index correlation in acoustic neuromas

Schwanomas do acústico são os tumores mais freqüentes localizados no ângulo pontocerebelar. Os mecanismos moleculares que levam a sua geração e crescimento ainda não são bem conhecidos. Várias características clínicas, radiológicas e imuno-histoquímicas já foram estudadas e correlacionadas ao crescimento tumoral. Estudamos e correlacionamos aspectos clínicos e imuno-histoquímicos (MIB-1) de 11 schwanomas do acústico operados no Hospital São Paulo/UNIFESP. O tamanho dos tumores correlacionou-se com o índice proliferativo (Ki-67), não havendo correlação com significância estatística entre a idade dos pacientes, duração dos sintomas e índice proliferativo.

Surgery of vestibular schwannomas: an institutional experience.

AIMS: To report management results of vestibular schwannomas (VS) treated surgically in our institute, with particular reference to completeness of tumor excision, facial nerve and hearing preservation and complications of surgery. STUDY DESIGN AND SETTINGS: Retrospective study of 259 patients treated during the years 1988 to 2002. MATERIALS AND METHODS: The facial nerve function and hearing assessment was done according to House-Brackmann [HB] grading and pure tone audiometry (PTA) respectively. All patients were operated by retro-mastoid sub-occipital approach. RESULTS: Most patients had large tumors and had no useful hearing (90%), had disabling cerebellar ataxia (88%) and presented with features of raised intra-cranial pressure (45%). Large sized tumors were in 41.3% and giant sized tumors were in 56% cases. Complete tumor excision was carried out in 96.5% and anatomical preservation of facial nerve was achieved in 79.2% cases. Hearing preservation was achieved in 8 patients. Cerebrospinal fluid leak with or without meningitis and transient lower cranial nerve paresis were common complications. The mortality was 6%. CONCLUSIONS: With experience, complete tumor excision with good facial nerve preservation can be achieved in large tumors. Hearing preservation is difficult in bigger tumors. Prevention and control of infection was a major concern.

Meningitis due to Enterobacter aerogenes subsequent to resection of an acoustic neuroma and abdominal fat graft to the mastoid

Meningitis is an uncommon complication of neurosurgical procedures, with an incidence of 1.1 percent to 2.5 percent. Although unusual, the frequency of nosocomial Gram-negative meningitis appears to be increasing. Gram-negative meningitis has been documented following disruption of the dura-arachnoid barrier secondary to trauma or surgery. The association of Gram-negative bacillary meningitis with neurosurgical procedures was first reported in the 1940's. Wolff et al. described the association between Enterobacter species and post-neurosurgical infection. More recently, risk factors for nosocomial Enterobacter meningitis have been characterized by Parodi et al. Adipose graft, as an independent risk factor has not yet been reported. A patient with acoustic neuroma resection, who developed bacterial meningitis from an abdominal fat pad graft to a mastoidectomy bed is described. A brief overview was made of post-neurosurgical Gram-negative meningitis.

Cavernous sinus thrombosis and air embolism following surgery for acoustic neurinoma: a case report.

A 55 year old male patient was operated on for a massive and vascular acoustic neurinoma in a sitting position. The tumor was completely excised. Post-operatively, the patient developed irritability and clinical features suggestive of contralateral cavernous sinus thrombosis. CT scan showed air within the dural walls of the cavernous sinus on the side of surgery. However, there was no radiological evidence of cavernous sinus thrombosis on the contralateral side. Cavernous sinus thrombosis as a post-surgery complication has not been reported. Air within the dural confines of the cavernous sinus has also not been observed or radiologically recorded in the literature.

Neurectomia vestibular e coclear no guinea pig vivo: via occipital / Vestibular and cochlear neurectomy in the alive guinea pig: an occiptal approach

Forma de estudo: Experimental Objetivo: Este artigo descreve uma nova via cirúrgica para atingir a inervatura vestíbulo-coclear (VIII par) no Guinea pig vivo. Essa via é totalmente óssea (exceto o acesso ao próprio osso), oque implica em poucos danos as estruturas nobres do animal, o qual é passível de recuperação para estudos posteriores do sistema vestibular e coclear e todas as suas referências, com o ouvido interno, médio e externo.Conclusão: Mesmo exigindo precisão e controle, dada a proximidade com estruturas vitais, ela se mostra bastante viável do ponto de vista prático e muito menos invasiva e danosa em relação a outras cirurgias realizadas com a mesma finalidade, por permitir exames de imitanciometria,Bera,vemp, reflexos estapediais e do tensor do tímpano,entre outros físicos ou fisioelétricos

Vestibular schwannomas: Clinical presentation, management and outcome

OBJECTIVE: To review the demographic trends clinical spectrum, diagnosis, management and out come of patients with vestibular Schwannoma and to identify areas where improvements are needed. METHODS: All patients with vestibular schwannoma admitted to the Aga Khan University Hospital over the past 11 years were reviewed retrospectively. The age range of majority of 22 patients analyzed, was 41-50 years [23%]. Hearing loss was the most common presenting symptom [96%]. Other clinical features included cranial nerve palsies [59%] and headache [55%]. Fifty% had signs of raised intracranial pressure. Neuroimaging revealed 'Stage IV b' [tumor distorting the brainstem and compressing the 4th ventricle] in 50% cases. Neurosurgical intervention was carried out in 86%; mainly using the retrosigmoid approach. Postoperative complications included facial nerve palsy in 13 [65%] and hydrocephalus in 5 [25%] patients. Hearing determined clinically was preserved in three patients [14%]. One patient died during the inpatient stay. Presentation of these patients is late and the outcome is poor

Neurinoma do acústico em crianças sem associaçäo com neurofibromatose: relato de dois casos / Acoustic neuroma in children without association with neurofibromatosis: report of 2 cases

O neurinoma do acústico é o tumor da regiao ângulo ponto-cerebelar mais comum em indivíduos adultos, sendo raro em crianças sem neurofibromatose. A literatura consultada mostra 18 casos bem documentados de crianças portadoras de neurinomas do VII nervo craniano com idade inferior a 16 anos. Relatamos dois casos de crianças com idade de 9 a 15 anos, portadoras desta patologia e submetidas a tratamento cirúrgico. Nestes casos, assim como nos relatados na literatura, o quadro clínico é semelhante ao do adulto, em que o primeiro sintoma é a surdez progressiva, mais tardiamente seguindo-se sinais e sintomas relacionados à lesao expansiva na fossa posterior.