Abstracts

Rationale: Epilepsy surgery in eloquent cortex has been heavily constrained by the expected surgical sequelae of the surgical procedures. Better focus localization and multimodal functional mapping have increased the possibilities of surgery in eloquent cortex related areas. After the last changes in our procedures, we have since May 2013 completed ten patients that were not seen as surgical candidates prior to the changes. This is the first report of the short term outcome in this group. Methods: Ten patients with an epileptic focus certainly or probably located in eloquent cortex, hence requiring awake craniotomy, are included in this study. Prior to surgery, they all had at least one extracranial LTM with at least 64 channels. Source localizations as implemented in commercial available software were used for better planning of the intracranial electrode placement. The intracranial recordings were also analyzed with source localization; dipoles, minimal norm methods and to some extent connectivity measures. At least one of the applied analyzes was constrained to the surface of lesion. All patients had surgery with an awake craniotomy (sleep-awake-sleep) some lasting more than 4 hours. The patients were tested according to expected functional affection throughout the procedure and resections were stopped at signs of function loss. Electrical stimulations were used in addition in some of the patients. Results: During surgery nine of the ten patients in this group had the epileptic focus in eloquent cortex and one was found in its proximity. Two of the patient had minor, expected function loss after surgery. Both have mainly recovered. At the moment seven of the patients are seen as seizure free. A good example: One patient had a migration disturbance as a heterotopia in the central sulcus expanding into both primary motor and sensory cortex. This was partly resected according to source localization. Patient is seizure free and without sequelae. Conclusions: This study shows that surgery may safely been done in eloquent cortex. Due to short observation period the outcome is uncertain, but the application of the new methods looks very promising.