Morbidity associated with the use of intracranial electrodes for epilepsy surgery.

BACKGROUND: Invasive monitoring for the investigation of medically intractable epilepsy may be associated with undesirable morbidity. We performed a review of our recent experience to determine the incidence of major complications.

METHODS: We reviewed the clinical records of all patients who underwent invasive EEG monitoring at our institution between 2000 and 2004.

RESULTS: One-hundred and sixteen patients (57 males, 59 females) with a mean age of 32 years of age underwent intracranial placement of electrodes for epilepsy surgery investigation. Subdural strips were placed in 115 patients with a mean of eight strips per patient. Subdural grids were inserted in 11 patients and depth electrodes in five. Fourteen of the 15 patients with grids or depth electrodes also had strips. Coverage was unilateral in 37 patients and bilateral in 79 patients. Electrodes were placed over the frontal lobe in 78 cases, temporal in 93, parietal in 24, and occipital in 27 patients. The average duration of investigation was 12.3 days (range 3-29). The evaluation led to the performance of a surgical resection in 85 patients (74%). Complications were seen in four patients with subdural strips (3%), and in two patients with grids (13%), characterized by clinical infection, intracranial hemorrhage, aseptic meningitis, transient neurological deficits, and status epilepticus. Mortality was nil.

CONCLUSIONS: In comparison with previously published literature on the topic, the major complication rate in this group of patients appears to be low.