Efficacy of and morbidity associated with stereoelectroencephalography using computerized tomography - or magnetic resonance imaging-guided electrode implantation

Object. The purpose of this paper was to define the general efficacy of and morbidity associated with stereoelectroencephalography using modern methods of imaging and to particularize the risks related to specific lobes of the brain. Methods. All patients admitted to the Montreal Neurological Institute who had undergone either computerized tomography- or magnetic resonance imaging-guided electrode implantation by one surgeon (A.O.) were reviewed. The procedure was considered efficient if the obtained information was sufficient to make a decision either in support of or against surgery. Two hundred seventeen patients underwent 224 implantations with 3022 electrodes. Complications related to each lobe were as follows: temporal lobe, two abscesses (0.54%); frontal lobe, one abscess and three hematomas (1.4%); and occipital lobe, one hypointense lesion found 1 week after electrode explantation (2.6%). Significant risk factors associated with hematomas were implantation in the frontal lobe (p < 0.05) and the use of four or more implanted electrodes (p < 0.025). General complications included the following: 26 patients, psychiatric symptoms during monitoring; one patient, meningitis; four patients, scalp cellulitis; and two patients, hemiparesis during angiography in the early 1980s. One of these latter patients maintained a mild hemiparesis and represents the only case of permanent neurological sequela in the entire series. Data obtained during recordings supported an indication for surgery in 178 patients (79.5%), excluded a surgical option in 37 patients (16.5%), and were unsatisfactory in nine patients (4%). Thus, the overall efficacy as defined previously was 96%. Conclusions. Stereoelectroencephalography is an efficient procedure with low associated morbidity. Bilateral exploration of the temporal lobes has a morbidity rate of approximately 1%. A higher risk of hematomas occurs with the implantation of four or more electrodes in the frontal lobes.