Objectives: The aim of this study is to demonstrate the accuracy of direct cortical stimulation of language areas preparatory to the removal of infiltrating tumors of dominant hemisphere.
Material and methods: From June 1998 to March 2000 we included in our study 15 patients, aged from 30 to 75 years, harboring gliomas (14 high grades and 1 low grade) close to language-specific cortex. All patients had slight inaugural phasic troubles. They underwent craniotomy under local anesthesia for cortical stimulation language mapping, in conjunction with electrocorticography to identify the after-discharge threshold. Stimulation mapping covered the entire macroscopically tumor involved area, extending up to 3 cm away from the margins of the lesion, without searching to identify systematically the language areas. Therefore, the lesion was removed as completely as possible, respecting a security margin of at least 1 cm from the recognized language sites.
Results: We identified from 1 to 6 language sites for 14 of our patients, in different locations. A radical removal was achieved for all high grade gliomas, while the low grade was only partially removed. A patient died on the 16th postoperative day from pulmonary embolism; 2 patients deteriorated from peri- or immediate postoperative complications; 9 showed a transient neurological worsening that receded by the 2nd postoperative month, while 3 did not present any postoperative aggravation. At a follow-up of 1 month to 2 years (mean 8 months), 6 patients died and the 9 survivors maintain a good life quality.
Conclusions: Cortical stimulation for language mapping is an accurate technique that allows the surgical morbidity of lesions in proximity to language areas to decrease and become comparable to the surgical morbidity for lesions in non eloquent areas.