The impact of microsurgery, stereotactic radiosurgery and radiotherapy in the treatment of meningiomas depending on different localizations

Scientific background: Meningiomas are the most common benign intracranial neoplasms with a slow growth presented as the intracranial lesion. These tumors are without any symptoms for a long time. At the time of diagnosis it is frequently an asymptomatic tumor. In that case the therapist may well suggest a wait-and-see strategy. The therapy of meningiomas focuses firstly on the microsurgical treatment. Volume reduction can be achieved immediately after treatment. Stereotactic radiosurgery is an important non-invasive treatment option for recurrent tumors or meningiomas with partial resection. The technical equipment for the stereotactic radiosurgery is a cost intensive investment. In this context the high precision of the intervention, presented as a low invasiveness of the treatment, is an important factor. The aim of this assessment is to identify the chances and limitations of the diverse treatment options and to estimate their outcome for different localisations of meningiomas. Methods: In December 2007 a systematic literature search was conducted using the most relevant medical databases. The whole strategy and the used search terms were documented. The literature search was supplemented with an internet and literature based hand search on law, ethics and economics. Primary studies and systematic reviews which report relevant outcomes are included in this analysis. The current assessment is based on the available evidence that was found at the time of the literature search. Results: A total of 31 publications for the medical focus of assessment and three reports from the economical hand search were included. In general, it is not possible to identify neither randomised clinical trials or prospective, contrasting cohort studies nor studies summarising results from such studies. The results presented in the literature published by surgeons strongly vary regarding localisation of meningiomas. Publications not differentiating between the localisation of meningiomas indicate a progression free survival rate of five years in 77 to 97% of the cases after complete surgical resection of the tumor, in 18 to 70% of the cases after subtotal resection and for patients who had undergone surgical resection and a combined radiotherapeutical treatment of their meningiomas a five year progression free survival rate between 82 and 97%. Other treatment options like hormone therapy or treatments to stop tumor growth had been used unsuccessfully so far. Based on the results presented regarding economic evaluation, costs resulting from radiosurgical treatment are lower in contrast to costs resulting from surgical resection. However, it has to be taken into account that costs resulting from radiosurgical treatment strongly depend on the number of patients treated in total with the radiosurgical equipment. Conclusion: Due to the strong dependencies between the results from surgical therapy and the localisation of the tumor, it is only possible to derive recommendations on whether or not to perform the surgical therapy with respect to the localisation of the tumor. Only for patients with tumors with a spinal localisation or WHO Grade I meningiomas with a cortical localisation, primary treatment with by means of microsurgery can be suggested. For all other localisations of the tumor, alternative treatment by radiosurgery should be discussed. From the literature identified, a clear recommendation of one or the other therapy however can not be deduced. Thus, there is a strong need for randomised clinical trials or prospective or contrasting cohort studies, which compare rigorously microsurgery with radiosurgery concerning different localisations of tumors

Successful resection of the recurrence of a cavernous malformation of the optic chiasm

The case of a 33-year-old female who suffered from a recurrence of an intrachiasmatic cavernous malformation is presented. She had already undergone surgery in 1991 and 2001 and was admitted to our hospital with reduced vision in the right eye. After MRI, and diagnosis of recurrence of the cavernoma, a neurosurgical operation was performed using the pterional approach. The intraoperative situation was documented with micro photographs. The postoperative course was uneventful. The female described a minimal improvement of her vision. No postoperative complications were observed. To our knowledge, microsurgically complete extirpation of a recurrence of an intrachiasmatic cavernoma has not yet been reported in the literature

The impact of microsurgery, stereotactic radiosurgery and radiotherapy in the treatment of meningiomas depending on different localizations

Scientific background Meningiomas are the most common benign intracranial neoplasms with a slow growth presented as the intracranial lesion. These tumors are without any symptoms for a long time. At the time of diagnosis it is frequently an asymptomatic tumor. In that case the therapist may well suggest a wait-and-see strategy. The therapy of meningiomas focuses firstly on the microsurgical treatment. Volume reduction can be achieved immediately after treatment. Stereotactic radiosurgery is an important non-invasive treatment option for recurrent tumors or meningiomas with partial resection. The technical equipment for the stereotactic r adio surgery is a cost intensive investment. In this context the high precision of the intervention, presented as a low invasiveness of the treatment, is an important factor.The aim of this assessment is to identify the chances and limitations of the diverse treatment options and to estimate their outcome for different localisations of meningiomas. Methods In December 2007 a systematic literature search was conducted using the most relevant medical databases. The whole strategy and the used search terms were documented. The literature search was supplemented with an internet and literature based hand search on law, ethics and economics. Primary studies and systematic reviews which report relevant outcomes are included in this analysis. The current assessment is based on the available evidence that was found at the time of the literature search. Results A total of 31 publications for the medical focus of assessment and three reports from the economical hand search were included. In general, it is not possible to identify neither randomised clinical trials or prospective, contrasting cohort studies nor studies summarising results from such studies. The results presented in the literature published by surgeons strongly vary regarding localisation of meningiomas. Publications not differentiating between the localisation of meningiomas indicate a progression free survival rate of five years in 77 to 97% of the cases after complete surgical resection of the tumor, in 18 to 70% of the cases after subtotal resection and for patients who had undergone surgical resection and a combined radiotherapeutical treatment of their meningiomas a five year progression free survival rate between 82 and 97%. Other treatment options like hormone therapy or treatments to stop tumor growth had been used unsuccessfully so far. Based on the results presented regarding economic evaluation, costs resulting from radiosurgical treatment are lower in contrast to costs resulting from surgical resection. However, it has to be taken into account that costs resulting from radiosurgical treatment strongly depend on the number of patients treated in total with the radiosurgical equipment. Conclusion Due to the strong dependencies between the results from surgical therapy and the localisation of the tumor, it is only possible to derive recommendations on whether or not to perform the surgical therapy with respect to the localisation of the tumor. Only for patients with tumors with a spinal localisation or WHO Grade I meningiomas with a cortical localisation, primary treatment with by means of microsurgery can be suggested. For all other localisations of the tumor, alternative treatment by radiosurgery should be discussed. From the literature identified, a clear recommendation of one or the other therapy however can not be deduced. Thus, there is a strong need for randomised clinical trials or prospective or contrasting cohort studies, which compare rigorously microsurgery with radiosurgery concerning different localisations of tumors.Hintergrund Meningeome sind meistens gutartige, langsam wachsende Tumore, die sich als intrakranielle oder intraspinale Raumforderung äußern. Da Meningeome über lange Zeit symptomlos bleiben, haben sie sich zum Zeitpunkt der Diagnosestellung häufig noch nicht manifestiert. In diesem Fall kann zunächst eine abwartende Haltung des Therapeuten eingenommen werden. Der Fokus der Therapiemaßnahmen stützt sich vor allem auf die chirurgische Entfernung des Tumors, da auf diese Weise eine sofortige Volumenreduktion erzielt werden kann. Eine nichtinvasive Maßnahme, die vor allem zur Nachbehandlung teilresizierter Tumore eingesetzt wird, stellt die stereotaktische Radiochirurgie dar. Für die stereotaktische Radiochirurgie ist eine aufwendige und kostenintensive Gerätetechnik notwendig. Der hohe Grad an Präzision, der durch einen steilen Abfall der Dosiskurven am Tumorrand gekennzeichnet ist, und die geringe Invasivität der Behandlung sind jedoch von zentraler Bedeutung. Das vorliegende Assessment soll die Möglichkeiten und Grenzen der unterschiedlichen Optionen in der Meningeomtherapie aufzeigen und das Outcome der Verfahren in Bezug zu den unterschiedlichen Lokalisationen der Meningeome bewerten. Methodik Die systematische Literatursuche erfolgt im Dezember 2007 in den wichtigsten medizinischen Datenbanken, wobei die in der Suchstrategie verwendeten Stichworte und ihre Verknüpfungen nachvollziehbar dokumentiert werden. Aufgrund der geringen Datenlage wird darüber hinaus für den Bereich der gesundheitsökonomischen Bewertungen eine Handsuche durchgeführt. Das gegenwärtige Assessment beruht somit auf der aktuellsten Evidenz themenbezogener Studien und Übersichtsarbeiten, die zum Zeitpunkt der Literatursuche zur Verfügung steht. Ergebnisse Insgesamt werden 31 Publikationen für die medizinische und drei Arbeiten für die gesundheitsökonomische Bewertung herangezogen. Die Ergebnisse der einzelnen Arbeiten sind stark abhängig von der Lokalisation des Meningeoms. Für die allgemeine Betrachtung der Meningeome werden vor allem Publikationen herangezogen, die ein progressionsfreies Intervall von fünf Jahren bei 77 bis 97% der Fälle nach kompletter chirurgischer Tumorentfernung beschreiben, bei 18 bis 70% nach subtotaler Tumorentfernung und bei 82 bis 97% nach kombinierter chirurgischer sowie strahlentherapeutischer Behandlung. Andere Therapieformen wie Hormontherapie oder Therapieformen, die dem Tumorwachstum entgegenwirken, zeigen bislang keinen durchgreifenden Erfolg. Der Kostenvergleich zwischen der Radiochirurgie mit dem Gamma knife und der mikrochirurgischen Operation fällt, bezogen auf die Daten aus der Literatur, zugunsten der Radiochirurgie aus. Allerdings stehen die Kosten der Radiochirurgie in unmittelbarer Abhängigkeit zur der Anzahl der mit der Intervention therapierten Patienten insgesamt. Schlussfolgerung Aus den vorliegenden Arbeiten kann lediglich zu einzelnen Lokalisationen von Tumoren ein Behandlungsvorschlag abgeleitet werden, da die Evidenzkategorie III nicht überschritten wird. In den meisten Fällen wird es somit eine Einzelfallentscheidung bleiben, die ausgehend von den Beschwerden des Patienten die operative Expertise des Neurochirurgen, die strahlentherapeutischen Möglichkeiten und letztlich den Patientenwunsch einbezieht.Dabei lässt sich eine primär chirurgische Therapie lediglich bei spinalen Tumoren und bei kortikal gelegenen Tumoren der Histologie Grad I vorschlagen. Alle übrigen Lokalisationen sind grundsätzlich auf mehrere Arten therapierbar und die vorliegende Literatur lässt bei dem existierenden Evidenzniveau keine eindeutigen Aussagen für oder gegen eine Therapie zu. Somit besteht die Notwendigkeit randomisiert kontrollierter Studien oder prospektiver Kohortenstudien, die in Abhängigkeit der unterschiedlichen Lokalisationen einen direkten Vergleich zwischen der Mikro- und der Radiochirurgie herstellen

Holographic optogenetic stimulation with calcium imaging as an all optical tool for cardiac electrophysiology

All optical approaches to control and read out the electrical activity in a cardiac syncytium can improve our understanding of cardiac electrophysiology. Here, we demonstrate optogenetic stimulation of cardiomyocytes with high spatial precision using light foci generated with a ferroelectric spatial light modulator. Computer generated holograms binarized by bidirectional error diffusion create multiple foci with more even intensity distribution compared with thresholding approach. We evoke the electrical activity of cardiac HL1 cells expressing the channelrhodopsin-2 variant, ChR2(H134R) using single and multiple light foci and at the same time visualize the action potential using a calcium sensitive indicator called Cal-630. We show that localized regions in the cardiac monolayer can be stimulated enabling us to initiate signal propagation from a precise location. Furthermore, we demonstrate that probing the cardiac cells with multiple light foci enhances the excitability of the cardiac network. This approach opens new applications in manipulating and visualizing the electrical activity in a cardiac syncytium

Análise de timol em cera de abelha por micro-extracção em fase sólida (SPME)

A aplicação contínua de acaricídas lipofílicos sintéticos no tratamento das abelhas conduz a uma acumulação que depende da frequência, lipofilicidade e quantidade de princípio activo utilizada. Este efeito é mais acentuado na cera de abelha que no mel, no entanto, e porque a persistência destes resíduos é elevada, provoca o aparecimento de resistências e a perda do seu efeito acaricida.[1] Esta razão levou à pesquisa de outros compostos alternativos não tóxicos e não persistentes, com efeito sobre o ácaro das abelhas, Varroa Jacobsoni. Entre estes compostos encontra-se o timol, um composto fenólico, volátil, presente no tomilho. Dos diversos componentes dos óleos essenciais este é sem dúvida o que demonstrou maior efeito acaricida, utilizando-se no tratamento das abelhas directamente ou como componente de diversas formulações.[2] Em Portugal, foi introduzido muito recentemente sob a forma comercial de APIGUARD: um gel, à base de timol, que controla termicamente a libertação do princípio activo. O controlo dos resíduos de timol na cera de abelha e no mel é assim um desafio actual quer do ponto de vista sanitário quer de qualidade alimentar. A micro-extracção em fase sólida (SPME) é uma técnica de preparação de amostras que se baseia na sorção de analítos no revestimento de uma fibra de sílica fundida e posterior desorção térmica no injector de um cromatógrafo em fase gasosa (GC). Para além de combinar num único processo etapas de extracção, purificação e concentração dos analitos, a técnica de SPME apresenta uma série de vantagens relativamente às técnicas de extracção convencionais, como a extracção líquido-líquido e extracção em fase sólida, nomeadamente a sua relativa simplicidade e rapidez, reduzido custo e não utilização de solventes para a extracção de analitos, para além de permitir a extracção por imersão directa na amostra gasosa ou líquida e extracção por amostragem do espaço-de-cabeça da amostra líquida ou sólida.[3] Ao contrário das técnicas tradicionais, que permitem uma extracção quantitativa dos analitos, a técnica de SPME baseia-se num equilíbrio de partição do analito. Esta particularidade torna a técnica de SPME bastante sensível a parâmetros experimentais que possam afectar os coeficientes de partição dos analitos e, consequentemente, a sensibilidade e reprodutibilidade dos resultados.[4] O objectivo deste trabalho é o desenvolvimento de uma metodologia para a análise de timol em ceras contaminadas, utilizando como padrão interno a benzofenona. Em primeiro lugar, procedeu-se à optimização da técnica através da determinação da quantidade de cera, temperatura de análise e período de contacto da fibra com o espaço-de-cabeça da amostra mais adequados para o caso em estudo. Numa segunda fase, procedeu-se à análise de diversas lâminas de cera contaminadas propositadamente com timol e sujeitas a diferentes condições de armazenamento: em frio, ao ar e em estufa. Finalmente, procedeu-se à construção da curva de calibração e quantificação do timol presente nas diversas amostras de cera analisadas. Considerando-se os resultados, para os níveis de contaminação avaliados, as condições analíticas mais adequadas ocorrem com a utilização de 1 g de cera, mantendo-se a fibra em contacto com o espaço-de-cabeça durante 40 minutos a uma temperatura de 60 ºC. Nestas condições experimentais foi possível obter uma boa correlação linear (r2=0,990) no intervalo de concentrações [3,5-14 mg/g]. A quantidade de timol encontrada nas amostras é significativamente inferior à colocada durante o processo de fabrico das lâminas, pelo que o processo de conservação não é o mais adequado, sendo evidente uma menor quantidade de timol quando a lâmina de cera é colocada na estufa