The treatment of foci resection and bipolar electro-coagulation on functional cortex in multifocal epilepsy associated with tuberous sclerosis complex involving eloquent cortex

Objectives: Tuberous sclerosis complex (TSC)-associated epilepsy is medically refractory seizures secondary to cortical tubers and leads to mental retardation in childhood. TSC patients are often with refractory epilepsy involving eloquent and noneloquent cortex in multiple lobes and multiple independent seizure foci which made these patients poor candidates for conventional surgery. We have previously presented that the approach of pure bipolar electro-coagulation on functional cortex (BCFC) in the treatment of unifocal epilepsy involving eloquent areas is effective, safe and easy to use. This report describes our long-term follow-up for combined resective surgery and BCFC in TSC patients with refractory epilepsy involving eloquent and noneloquent cortex.

Methods: 8 patients aged from 8 to 31 years were admitted with epilepsy. The cranial computerized tomography (CT) showed cortical and subependymal calcification, magnetic resonance imaging (MRI) demonstrated multiple cortical tubers. All patients were with drug resistant epilepsy, despite treatment with two antiepileptic drugs (AEDs). Initiated combination therapy of foci resection and BCFC for epilepsy management between May 2004 and May 2012, the patients were retrospectively reviewed with regard to seizure outcome, postoperative complications.

Results: The combination therapy of foci resection and BCFC resulted in remarkable improvement in patient's ambulation and cessation of seizures. Engel class I outcome was achieved in 3 patients, Engel class II in 3 patients, Engel class III in 1 patient and Engel class IV in 1 patient. All patients were with no permanent neurological deficit noticed during a standard clinical examination. In addition, all patients showed some improvement in behavior or cognitive function (Figs. 1–3).

Fig. 1 – (a) Interictal-1 displays as bilateral symmetric high amplitude of multi-spike and slow waves during sleep. (b) Interictal-2 shows low to medial amplitude of awake multi-spike and slow waves on the right frontal (F4, F8), central (C4) and temporal (T4). Clinical seizures were characterized by tonic of left arm, laughing (Gelastic seizures) and followed by secondary generalized tonic seizures. (c) The corresponding ictal EEG revealed bilateral epileptiform discharge, more predominant over the right frontal (F4, F8), central (C4) and temporal.

Fig. 2 – (a) Pre-resection EcoG revealed significant spiking in the central (eloquent epileptogenic zone) (arrows). (b) Extremely active interictal spikes were noted in the post-resection EcoG (arrows). (C) No epileptiform discharges were present over right central cortex after the BCFC procedure.

Fig. 3 – (a) Selective resection of the epileptogenic zone in the right frontal lobe (red arrows) and BCFC in the central (blue arrows) and the electrocoagulated cortex presented red and white stripes at regular intervals. (b) Brain specimen showing the tubers (circle). (c) Immunohistology image showing giant cells (balloon cells) and dysmorphic neurons.

Conclusions: The combination therapy of foci resection and BCFC is an effective and safe surgical approach for the treatment of TSC-associated epilepsy involving eloquent cortex.