Radiochirurgie und fraktionierte stereotaktische Radiotherapie des Vestibularisschwannoms

[Vestibular Schwannoma: Factors in Therapy Decision-Making]

The treatment of vestibular schwannomas (VS) has always posed a challenge for physicians. Three essential treatment principles are available: wait-and-scan, surgery, and stereotactic radiotherapy. In addition to the type of treatment, decisions must be made regarding the optimal timing of therapy, the combination of different treatment modalities, the potential surgical approach, and the type and intensity of radiation. Factors influencing the therapy decision include tumor location and size or stage, patient age, comorbidities, symptoms, postoperative hearing rehabilitation options, patient preferences, and, not least, the experience of the surgeons and the personnel and technical capabilities of the clinical site. This article begins with a brief overview of vestibular schwannomas, then outlines the fundamental interdisciplinary treatment options, and finally discusses the ENT (ear, nose, and throat)-relevant factors in the therapy decision.

[Acoustic neuromas : Differential diagnoses]

CLINICAL ISSUE

Acoustic neuromas in adults are the most common infratentorial tumors that originate from the Schwann's cells of the vestibular part of the eighth cranial nerve and are clinically noticeable through neurological deficits, such as unilateral hypoacusis, tinnitus, dizziness and unilateral facial nerve palsy. Due to the widespread use of computed tomography (CT) and magnetic resonance imaging (MRI), acoustic neuromas can now be diagnosed with a high rate of sensitivity and specificity; however, there are a number of possible differential diagnoses, such as meningioma, epidermoid and metastases as well as a number of less common diagnoses, such as peripheral nerve sheath tumors, sarcoidosis/neuritis and lipomas, which are sometimes difficult to distinguish from acoustic neuromas. Particularly smaller findings can often only be differentiated with the aid of a histopathological investigation.

PRACTICAL RECOMMENDATIONS

Small intrameatal and asymptomatic acoustic neuromas, some of which are discovered as incidental findings, do not require immediate treatment and should instead be monitored by MRI. Larger findings that are symptomatic and thus cause a number of severe neurological symptoms that are stressful for the patient, should be surgically removed. In cases where surgical treatment is not possible or for smaller symptomatic findings, radiotherapy can also be considered as an alternative.

[Surgical indications and complications management in vestibular schwannoma]

BACKGROUND

Recent surgical treatment concepts for patients with vestibular schwannoma (VS) require an interdisciplinary approach as well as recognition and mastering of complications.

OBJECTIVE

This paper provides an overview of indications, as well as possible options for function preservation and management of complications in the surgical resection of these tumors.

METHODS

Up-to-date treatment concepts and surgical indications were differentiated according to size and extent of tumors. The frequency of important complications was extracted from the literature. Technical options to avoid and correct complications were compiled from personal experience and review of the literature.

RESULTS

Complications unrelated to cranial nerves are not infrequent, particularly in older patients. Small and medium-sized tumors that do not reach the fundus and cochlear fossa can be completely removed with good chances of hearing preservation. As long as these tumors do not grow, patients benefit from observation. Large tumors are overrepresented in surgical series compared to their prevalence. Postoperative facial nerve function correlates to tumor volume. Hearing preservation in these tumors is rare. Intraoperative electrophysiological techniques are valuable for attempted preservation of cranial nerve function. Persistent facial palsies can be remedied by dynamic and static interventions for facial rehabilitation.

CONCLUSION

Mortality and morbidity associated with surgical treatment of VS are very acceptable. Surgical concepts should be custom-tailored to the individual patient in order to ensure high quality of life.