Though advances in cranial base surgery have improved outcomes, the risk of significant morbidity remains. Recently, fractionated gamma knife radiosurgery (FGKS) has been performed for an increasing number of patients with surgically high-risk meningiomas. We retrospectively reviewed short term radiosurgical outcome of 25 patients with meningiomas who underwent FGKS. The patients had minimal symptoms.

     Mainly, we reviewed the tumors located on the skull base which were surgically challenging portion. Some of the patients were reviewed because of old age and large tumor size. And we also include the patients with meningioma proximity to critical structure such as optic nerve.

     Between 2006 and 2010, 25 patients (mean age of 60.08, 8 male and 17 female) with large or risky skull base meningioma with minimal symptom underwent FGKS. Meningiomas located skull base (21), parasagittal(2), orbital(1), frontal(1).

       The tumor volumes ranged from 3.6 to 52.6 ml (median 18.5 ml). Median dose of 6.14Gy (ranged from 4.5 to 8 Gy) delivered over median of 2.76 fractionations (ranged from 2 to 4). We can expect the early same radiologic effect 14Gy single dose when 6.5Gy radiation delivered over 3 fractionations. The patients were followed by MRI median 24.48 month from GKS (ranged from 7 to 52). During follow-up, we evaluated neurological status of patients and changes of tumor volumes.

     During a median follow-up of 24.5 months, tumor volume decreased (> 25%) in 3 patients (12%), remained stable (volume change < 25%) in 21 (84%), and increased (> 25%) in 1 (4%). All patients had minimal complaints such as dizziness, headache, visual symptom, etc. The neurological status improved or remained unaltered in 24 patients (96%), and deteriorated in 1 patient (4%). During follow-up, local control rate of tumor was 96% and the control rate of symptom was also 96%.

     This was a retrospective study.

     Between 30% and 56% of the patients suffered postoperative complications in skull base meningiomas. When the patients presents minimal symptom and are expected high morbidity, FGKS showed excellent local control rate and low morbidity.

     Although we should study long term result and radiologic effect, we suggest FGKS for a good alternative tool for surgically challenging meningiomas.