[Grade I and II vestibular schwannomas: hearing, clinical course. Pre- and postoperative aspects].

We propose a point by point response to the questions raised at this round table concerning the spontaneous and postoperative course of grade I and II vestibular schwannomas, focusing on hearing function. The questions concerning non-operated schwannomas are: For operated schwannomas, the questions are: Spontaneously, 75-80% of these schwannomas progress significantly with a degradation of hearing function in more than half of the cases. We monitor clinical disorders and order routine audiometry and MRI. For us, Gardner and Roberson class A or 1 is truly useful hearing function. Preservation of truly useful hearing function after microsurgery is no better than 10%; satisfactory facial motor function is preserved in 70-80% of the cases with grade I, II, or III schwannomas and in more than 50% for grade IV schwannomas. Incomplete excision to preserve hearing function is compromised by recurrence. We preferably treat the smaller grade I schwannomas by radiosurgery to halt tumor progression and attempt to preserve hearing function.