The prognostic role of electrocorticography in tailored temporal lobe surgery

Intraoperative electrocorticography (ECoG) has been in clinical use for many decades, yet the validity of this procedure in guiding resective surgery for temporal lobe epilepsy (TLE) is still uncertain, especially in tailored temporal lobectomies in cases of TLE with hippocampal sclerosis.

Using a case-control design combined with descriptive and comparative analyses we retrospectively evaluated two groups of patients: patients (n=20) who had tailored temporal lobectomies guided by intraoperative ECoG and patients (n=19) who had standard temporal lobectomies without ECoG. Clinical and neuroimaging data, pre- and post-resection ECoG recordings, and seizure-free outcomes were reviewed.

Of the 20 patients who underwent epilepsy surgery guided by ECoG, pre-resection ECoG studies found spikes both in mesial temporal lobe (MTL) and lateral temporal lobe (LTL) in 10 patients, and restricted to the LTL or MTL in 7 and 3 patients respectively. Postsurgical ECoG captured residual epileptiform activity in only 3 patients, all of whom had MTL and LTL spikes prior to surgery. Postsurgical follow-up at 16.3 (±6.7) months found 15 (75%) patients were seizure free (1A), while 5 (25%) had other outcomes. Analysis found no difference in the proportion of seizure-free outcomes between patients with residual epileptiform activity compared to those without residual epileptiform activity, or between patients who had a tailored resection guided by ECoG and patients who had standard resections without ECoG monitoring.

The patients who underwent tailored temporal lobe epilepsy surgery guided by ECoG had similar outcome compared with the patients with epilepsy surgery not guided by ECoG.