Gamma knife radiosurgery of skull base

In 127 patients with skull base meningiomas 134 Gamma Knife radiosurgical procedures were performed. The age of these patients ranged from 10-8O years. Radiosurgery was performed as a primary treatment in 64 patients. Sixty-three patients had open surgery and subsequent radiosurgical treatment. The mean tumor volume was 8.4 ccm. It was covered by mean isodose volumes of 45% and treated by a mean dose of 13 Gy at the tumor border. Five patients underwent radiosurgery with staged treatment protocols and 4.6-39 months intervals. Follow-up imaging revealed decreased volume of tumor in 43 cases (49%); in 43 patients (49%) tumor progression was stopped, and in one case (1%) slight increase was observed. In this case as well as in 14 other cases (16%) marked central tumor necrosis was seen. Neurological follow-ups showed a stable status in 65%, amelioration in 30% and slight worsening in 5% (4 cases) of the patients.