Schwannoma of the Intermediate Nerve: A Rare Type of Cerebellopontine Angle Tumor

Abstract Background: Schwannoma of the Intermediate Nerve is rare. The most majority of Cerebellopontine angle (CPA) lesions are Vestibular Schwannomas. Case description: A 50-year-old woman presented with ear pain, facial palsy and hypoacusis. MRI revealed a CPA tumor. A left retrosigmoid approach and microsurgery was performed and the tumor origin was from the intermediate nerve. intraoperative neurophysiologic monitoring (MNIO) was used during the surgery. Conclusion: Schwannomas of the intermediate nerve is indistinguishable from vestibular schwannomas on preoperatory image, however it's possible to identify tumor origin during microsurgery dissection with aid of MNIO and origin from intermediate nerve is a reality

Stereotactic radiosurgery in the treatment of brain metastases: efficacy and complications based on brain location

As metástases cerebrais são os tumores cerebrais mais freqüentes do sistema nervoso central. Entre as modalidades terapêuticas, a radiocirurgia (SRS) vem ganhando destaque nas duas últimas décadas como forma efetiva de tratamento associada com baixa morbidade e mortalidade. Porém, mesmo após ampla revisão da literatura, várias perguntas permanecem sem resposta sobre a radiocirurgia no tratamento das metástases cerebrais, perguntas estas principalmente relacionadas sobre as complicações tardias, dependência ao corticóide e relação das complicações com áreas cerebrais funcionais eloqüentes. O objetivo deste trabalho foi analisar a radiocirurgia como modalidade terapêutica das metástases cerebrais (MC) de uma grande série de casos, que estuda criteriosamente clínica e radiologicamente as lesões e identificando fatores preditivos para complicações, falha terapêutica e necrose pós-tratamento, a qual enfatiza principalmente localização da MC e suas relações com áreas eloqüentes cerebrais. Foi realizado estudo retrospectivo em 213 pacientes com 261 metástases cerebrais tratadas com radiocirurgia. Várias características demográficas deste grupo de pacientes foram analisadas, onde destacamos a boa distribuição de lesões de várias histologias tratadas e na grande maioria de pacientes em bom estado geral. Além disso, dividimos estes tumores de acordo com uma classificação estabelecida para relação com áreas eloqüentes em 3 grupos (graus I, II e III). No nosso estudo encontramos dependência ao corticóide em 24,3% dos casos, que se distribui em 15%, 25% e 29% nas lesões grau I, II e III respectivamente. O autor demonstra que o dobro das lesões localizadas nas áreas eloqüentes apresenta dependência ao corticóide, comparando-se com tumores em áreas não eloqüentes. Destacamos que a dependência ao esteróide ocorre em 54,5% dos tumores do tronco cerebral, 38,8% dos relacionados com centro motor/sensitivo, 35,5% daqueles relacionados com centros da fala e 20% dos casos relacionados com áreas visuais. Também nestes grupos específicos ocorreu queda destas taxas de dependência com o passar dos meses. Na nossa casuística, a SRS foi efetiva em 184 lesões tratadas (70,5%), diante de acompanhamento prolongado. As complicações em geral foram mais freqüentes em áreas eloqüentes, ocorrendo, especificamente, em 64,7% , 64,9% e 55,3% respectivamente, para lesões do tronco cerebral, centros da fala e áreas motoras/sensitivas. Dentre as muitas variáveis utilizadas encontramos diferenças significativas para complicações para casos com doença primária progressiva, lesões grau III (áreas eloqüentes), lesões do tronco cerebral e relacionadas com áreas motoras/sensitivas. Se estudarmos apenas os casos com falha terapêutica, notamos diferenças para predizer falha terapêutica em casos com doença sistêmica avançada, a não realização de radioterapia prévia e lesões relacionadas com áreas motoras/sensitivas e centros da fala. Foram considerados fatores preditivos de necrose pós-tratamento metástases de melanoma e carcinoma de células renais, presença de metástases outras além do encéfalo, realização prévia de radioterapia, doses acima de 20 Gy e tumores relacionados com áreas motoras/sensitivas. Em todas as análises, notamos diferenças significativas quanto maior o tamanho da lesão tratada. Não houve diferenças significativas quanto à efetividade ou complicações comparando as várias histologias, ocorrendo diferenças para o surgimento de necrose póstratamento em casos das lesões consideradas \"radioresistentes\" (melanoma e carcinoma de células renais). Considerando os resultados obtidos, concluise que a realização de radioterapia prévia a radiocirurgia esteve associada com maior efetividade e maior possibilidade de ocorrer necrose póstratamento. Doença primária em estágio avançado foi considerada como fator preditivo de complicação e de falha terapêutica. Lesões maiores apresentaram significativas diferenças para complicações, falhas terapêuticas e necrose pós-tratamento, do que lesões menores. Podemos concluir, ainda, que a localização da metástase cerebral deve ser considerada uma variável importante em predizer complicação do tratamento, visto que encontramos significativas diferenças para o surgimento de complicações em lesões localizadas em áreas eloqüentes (grau III) e ainda especificamente em lesões do tronco cerebral e em áreas motoras/sensitivas, comparando-se com demais regiões cerebrais. Tais áreas também apresentaram maior taxa de dependência ao corticóideBrain metastases are the most common Central Nervous System tumors. Among the therapy options stereotactic radiosurgery has became in the last two decades an usefulness treatment technique attending with lower complication and mortality rate. However, even an extended literature review, many questions remain unclear about this therapy modality, mainly related with long-term complications, steroids dependency, and relations with brain eloquent areas. The goal of this project is analyze stereotactic radiosurgery as treatment modality for brain metastases in a large series, considering clinics and radiologic lesions aspects and identifying predictors factors for complications, treatment failure and treatment necrosis regarding the relation with brain eloquent areas. We retrospectively review 213 patients with 261 brain metastases treated with stereotactic radiosurgery. Several demographics aspects were analysed. We noticed a good distribution of histological groups and the performing patient status. We also lump these lesions in groups based on their location in relation with eloquent brain areas (grade I, II and III). This study found a general steroids dependency rate of 24,3% for all cases, occurring in 15%, 25% and 29% in lesions grade I, II and III respectively. That\'s twice the frequency for lesions located in eloquent brain areas compared with non eloquent located lesions. Specifically, the steroids dependency occurred in 54,5% of brain stem tumors, 38,8% tumors related with motor/sensory centers, 35,5% speech center tumors related and 20% of cases related with visual areas. Even in these subgroups the dependency rate decreases with time. The long-term tumor local control was achieved in 184 treated lesion (70,5%). Complications were more often found in eloquent areas, specifically in 64,7%, 64,9% and 55,3% respectively for brain stem, speech centers and motor/sensory related lesions. Among all variables we found significant differences for complications in cases of progressive primary disease, lesions grade III (located in eloquent areas), brain stem lesions, and related with motor/sensory areas. Regarding only treatment failure prediction, we noticed significances in cases of progressive primary disease, none previously radiated cases, and lesions related with motor/sensitive and speech areas. We considered predictors of treatment necrosis melanoma and renal cell carcinoma metastases, extra-cranial metastases, previously radiated patients, doses > 20Gy. In all analysis we found significant differences as bigger as the treated lesion. We did not find significant differences regarding efficacy and complication comparing all histological types. We identify statistically significant considering \"radioresistent\" tumors for treatment necrosis. Based on the results, we conclude that radiotherapy previously stereotactic radiosurgery were related higher effectiveness and treatment necrosis. Progressive primary disease predicts complications and treatment failure. Bigger lesions were statistically significant related with complications, treatment failure and necrosis compared with smaller ones. We can also conclude that brain location of metastases is an important variable to predict complications, with results that showed statistically significant differences found in grade III lesions, specifically brain stem tumors, lesions related in motor/sensitive areas, compared with non eloquent located lesions. These areas are also related with higher steroids dependency rate

Brain Functions: Eloquent Areas – Motor and Somatosensory

Intraoperative monitoring and mapping may allow real-time risk stratification and intraoperative guidance of the surgical strategy. During surgery under general anesthesia, diverse monitoring and mapping techniques have been developed, which will be discussed in the following chapter. Transcranial and direct cortical stimulation for monitoring motor evoked potentials helps to assess the functional integrity of the primary motor system and allows predicting motor functional outcome of the patients. Cortical mapping identifies eloquent areas and helps to define safe entry sites to resect tumors. Subcortical mapping is essential to preserve white matter tracts such as the corticospinal tract. Besides the classical intermittent mapping techniques, recently, continuous dynamic mapping approaches via surgical instruments have evolved

Interfascial dissection for protection of the nerve branches to the frontalis muscles during supraorbital trans-eyebrow approach: an anatomical study and technical note

Introduction Preservation of the temporal branches of the facial nerve during anterolateral craniotomies is important. Damaging it can inflict undesirable cosmetic defects to the patient. The supraorbital trans-eyebrow approach (SOTE) is a versatile keyhole craniotomy but still has a high rate of frontalis muscle (FM) palsy. Objective Anatomical study to implement the interfascial dissection during the SOTE to preserve the nerves to the FM. Methods Slight modification of the standard technique of the SOTE was performed in 6 cadaveric specimens (12 sides). Results Distal rami to the FMwere exposed. The standard "U-shape" incision of the FM can cross over the nerves. Alternatively, an "L-shape" incision was performed until the superior temporal line (STL). An interfascial dissection was performed near to the STL and the interfascial fat pad was used as a protective layer for the nerves. Conclusion Various pathologies can be addressed with the SOTE. In the majority of the cases the cosmetic results are good, but FM palsy remains a drawback of this approach. The interfascial dissection may be used in an attempt to prevent frontalis rami palsy773265270sem informaçã

Comparison between the C5 or C6-Cz electrode assembly and C3 or C4-Cz assembly for transcranial electric motor activation of muscular response of the contralateral facial nerve

We used an assembly of electrodes C3 and C4-Cz in order to activate the motor cortical area of the corticobulbar tract to elucidate the motor-evoked potential of the contralateral mentalis muscle. We compared this setup to that of an assembly with electrodes C5 or C6-Cz using a train of electrical pulses and a single electrical pulse. This analysis was made in 23 consecutive patients who underwent several varied surgeries and were prospectively operated on at Santa Paula Hospital between January and June 2011. The results showed that the assembly with C5 or C6-Cz produced a multisynaptic motor-evoked potential in the contralateral mentalis muscle in 86.9 % of the patients, whereas 82.6 % of patients stimulated at points C3 or C4-Cz presented the same response. However, both assemblies showed similar behavior with the use of a single electrical pulse for peripheral contralateral nerve stimulation. We concluded that the C5 or C6-Cz assembly was similar to C3 or C4-Cz in obtaining a multisynaptic response in the contralateral mentalis muscle, although it required less intensive stimulation than the C3 or C4- Cz assembly

Best practices for the use of intracerebroventricular drug delivery devices

For decades, intracerebroventricular (ICV), or intraventricular, devices have been used in the treatment of a broad range of pediatric and adult central nervous system (CNS) disorders. Due to the limited permeability of the blood brain barrier, diseases with CNS involvement may require direct administration of drugs into the brain to achieve full therapeutic effect. A recent comprehensive literature review on the clinical use and complications of ICV drug delivery revealed that device-associated complication rates are variable, and may be as high as 33% for non-infectious complications and 27% for infectious complications. The variability in reported safety outcomes may be driven by a lack of consensus on best practices of device use. Numerous studies have demonstrated that employing strict aseptic techniques and following stringent protocols can dramatically reduce complications. Key practices to be considered in facilitating the safe, long-term use of these devices are presented.(VLID)469777