Diagnostik und Therapie des Vestibularisschwannoms – eine interdisziplinäre Herausforderung

Zusammenfassung

Vestibularisschwannome wachsen langsam im inneren Gehörgang, im Kleinhirnbrückenwinkel, intracochleär und intralabyrinthär. Größere Tumoren verdrängen und komprimieren den Hirnstamm. Bei einer jährlichen Inzidenz von 1:100 000 repräsentieren Vestibularisschwannome 6–7% aller intrakraniellen Tumore und sind mit einem Anteil von 90% der häufigste Tumor im Kleinhirnbrückenwinkel. Magnetresonanztomografie (MRT), Audiometrie und Vestibularisdiagnostik sind die wesentlichen Säulen der klinisch-apparativen Untersuchungen.

Eine Übersicht über Tumorstadien, gebräuchliche Skalen zur Beurteilung der Fazialisfunktion und des Hörvermögens sowie eine kurze Darstellung aktueller Methoden der Vestibularisdiagnostik findet sich im ersten Teil dieses Referates.

Zentrales Anliegen in der Beratung und Behandlung von Patienten mit Vestibularisschwannomen ist heute die dauerhafte Aufrechterhaltung oder Verbesserung der Lebensqualität. Die Erhaltung neuronaler Funktion steht dabei im Vordergrund, die Behandlungskonzepte – Beobachtung, Operation, stereotaktische Bestrahlung und Kombinationen – werden an die individuelle Situation des Patienten angepasst. Wichtig für die Qualitätskontrolle und die Verbesserung der Behandlungsergebnisse ist dabei der beständige, interdisziplinäre Dialog. In den vergangenen Monaten sind in nationalen und internationalen Zeitschriften zahlreiche Übersichtsarbeiten zum Thema Vestibularisschwannome erschienen. Auch anlässlich des HNO-Kongresses 2017 erscheint ein Sonderheft zu diesem Thema. Aus diesem Grund soll dieses Manuskript von der traditionellen Form im Sinne einer Literaturübersicht und der Zusammenfassung der aktuellen Behandlungsstandards bewusst abweichen. Das vorliegende Referat wurde daher als eine interdisziplinäre Fallsammlung konzipiert, in der für jedes Stadium der Erkrankung anhand von Beispielen Verlaufsbeobachtungen sowie mikrochirurgische und radiotherapeutische Möglichkeiten des Managements gezeigt werden. Daraus wird eine Systematik in Form von Entscheidungskaskaden und klinischen Behandlungspfaden entwickelt. Wesentliche Kriterien bei der Entscheidungsfindung zur Behandlung sind die Größe des Tumors, seine Wachstumsgeschwindigkeit, das Hörvermögen des Patienten bzw. die Wahrscheinlichkeit einer möglichst vollständigen Resektion unter Erhaltung der Hörfunktion und der Funktion des Fazialis, das Alter und Vorerkrankungen des Patienten, die möglichst gute Kontrolle der für die Lebensqualität so wichtigen Faktoren wie Vertigo und Tinnitus und letztlich auch die Neigung des Patienten. In die Entscheidung fließen Erfahrungen und Ergebnisse des jeweiligen Behandlungszentrums mit der einen oder anderen Behandlungsmodalität ein.

Die aktuellen Literaturbefunde zu Fazialisfunktion, Hörvermögen, Schwindel, Tinnitus und Kopfschmerzen im Rahmen des natürlichen Verlaufes und von Behandlungen werden anschließend im Detail diskutiert und ihr Einfluss auf die Lebensqualität von Patienten mit Vestibularisschwannomen dargestellt. Das Symptom Schwindel spielt hier eine zentrale Rolle, weil es einer der wesentlichsten Prädiktoren von Lebensqualität und Arbeitsfähigkeit des Patienten ist.

Die pathognomonischen, bilateralen Vestibularisschwannome, die im Rahmen der Neurofibromatose Typ 2 auftreten, unterscheiden sich im biologischen Verhalten von spontanen, unilateralen Tumoren. Die Behandlung der Patienten mit diesen bilateralen Tumoren bedarf, schon wegen der oft zahlreichen weiteren intrakraniellen und spinalen Läsionen, eines multidisziplinären Teams. Als zusätzliche Off-Label-Behandlungsoption ist hier der Einsatz von Bevacizumab möglich, wodurch die Größe der Vestibularisschwannome über längere Zeiträume konstant gehalten und ein drohender Hörverlust verzögert werden kann. Eine Rehabilitation des Hörens kann bei NF-2-Patienten mittels Cochlea- und Hirnstammimplantaten möglich sein.

ABSTRACT

Vestibular schwannomas expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100 000 vestibular schwannoma represent 6–7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function.

Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options – watchful waiting, microsurgery and stereotactic radiation – should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several manuscripts and reviews have been published on the topic of vestibular schwanomma. On the occasion of the 88^th annual meeting of the German Society of Oto-rhino-laryngology, Head and Neck surgery a special volume of the journal “HNO” will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases which outlines examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and co-morbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient’s preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process.

We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient’s quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient’s dependence on social welfare.

Pathognomonic bilateral vestibular schwannoma that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions.

Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlea and auditory brainstem implants.

Schlüsselwörter

Vestibularisschwannom - Akustikusneurinom - Management - Radiochirurgie - Mikrochirurgie - Lebensqualität

Key words

vestibular schwannoma - acoustic neurinoma - management - microsurgery - radiosurgery - quality of life

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