An acoustic tumor (acoustic neuroma, vestibular schwannoma) is a benign (not cancerous) growth of the hearing and balance nerve. It mostly causes hearing loss and balance symptoms. Some of these tumors do not show clinically relevant growth tendencies over several years and the decision of having these removed remains challenging and multi-factorial. Factors such as the patient’s age, hearing, balance function, and the tumor location and size should be carefully weighted.
With larger tumors, however, removal becomes often necessary. Depending on the presence of functional hearing on the affected ear, various surgical approaches are available. Specifically, three main access routes are commonly used: the translabyrinthine approach, the middle fossa approach, and the retrosigmoid craniotomy.
Each approach has certain advantages and disadvantages. The middle fossa approach, for example, should only be used for smaller tumors. The retrosigmoid approach, on the other hand, can be used for medium sized tumors with intended hearing preservation. The translabyrinthine approach can be used for any tumor size but will compromise hearing in the affected ear.
Surgically, preservation of the facial nerve, which moves the facial muscles, remains the greatest priority. Tumors usually compress the nerve and push it against other structures. Recent advances in acoustic tumor surgery have suggested subtotal tumor removal and subsequent radiation if facial function would likely be impaired during surgery. Thus, a more symptom oriented approach is currently being adopted that includes multiple treatment modalities such as stereotactic radiation via a Gamma or CyberKnife.