Management of intrameatal vestibular schwannoma - Microsurgery, radiosurgery or "wait and scan"

The growth of purely intrameatal vestibular schwannoma (VS) was investigate d in the period 1973 96 in a series of 40 patients with 40 unilateral VS. I n the present study, the material was analysed and updated. By the end of t he observation period (mean 3.6 years), 27 tumours (67.5%) revealed growth and 13 tumors (32%) had no measurable growth. Four growth patterns were obs erved: (A) 15 rumours (37.5%) exhibited constant growth: (B) 13 tumors (32. 5%) had no measurable growth: (C) 8 tumours (20%) revealed growth subsequen t to a no-growth period: and (D) 13 tumours (10%) showed different growth p atterns during the observation period. The annual diameter growth rate rang ed between 00 mm,year and 6.5 mm/year and the mean diameter growth per year was 3.2 mm. The findings of the present study, especially those for group B (the non-growing tumours) and C (tumour growth subsequent to a silent per iod) bring into question the reliability of thr results achieved by radiosu rgery, as without any-intervention it may be that no tumour growth occurs.