Object. The purpose of this paper was to assess the early complications, de
fined as occurring within 1 year, following gamma knife radiosurgery (GKS)
for the treatment of intracranial meningiomas.
Methods. Seventy-seven of 306 patients undergoing GKS in the last 2.5 years
harbored meningiomas. There were 35 men and 42 women with a mean age of 32
.4 years (range 10-80 years). Tumor volume ranged from 0.35 to 28.6 cm(3) (
mean 7.9 cm(3)). Gamma knife radiosurgery was the primary therapy in 28 pat
ients and followed surgery in 49 patients. There were 50 basal and 27 nonba
sal meningiomas. The most common sites were parasagittal (23 patients) and
cerebellopontine angle (14 patients). Ten to 15 Gy was administered to the
tumor margins.
Clinical and radiological follow up with a mean duration of 122 months was
available in 40 patients. Seizures and increased headache were found in fiv
e and four patients, respectively. A temporary worsening of hemiparesis was
seen in two patients (both with parasagittal tumors). One patient with a c
avernous sinus meningioma developed a herpes labialis eruption. Perilesiona
l edema was demonstrated in nine patients and was symptomatic in six. Six (
22%) of the 27 patients with nonbasal tumors had edema tall parasagittal) a
nd four patients were symptomatic. Only three (6%) of the 50 basal meningio
mas had edema, and only one patient was symptomatic. The occurence of edema
did not correlate with tumor volume, margin or maximum dose, or with radia
tion received by adjacent brain. A reduction in tumor size was seen in seve
n patients. In one patient a new recurrent lesion developed adjacent to the
previously treated tumor.
Conclusions. Although GKS provides good results for selected patients with
meningiomas, caution is required in treating patients with parasagittal tum
ors as the incidence of perilesional edema is considerable.