Klinische Neurophysiologie 2014; 45 - V31
DOI: 10.1055/s-0034-1371210

Enhancing diagnostic accuracy in presurgical evaluation: invasive recordings with a combination of subdural grids plus depth electrodes

T Herberhold 1, T Pieper 1, M Kudernatsch 2, B Pascher 1, T Hartlieb 1, K Weber 1, H Eitel 3, T Getzinger 1, H Holthausen 1, P Winkler 1, I Blümcke 4, M Staudt 1
  • 1Epilepsy Center for Children and Adolescents, Schoen Klinik, Vogtareuth, Deutschland
  • 2Clinic for Neurosurgery and Epilepsy Surgery, Schoen Klinik, Vogtareuth, Deutschland
  • 3Klinik für Kinder- und Jugendliche, Esslingen, Deutschland
  • 4Department of Neuropathology, University Hospital, Erlangen, Deutschland

Introduction:

Patients suffering from intractable focal epilepsy due to focal cortical lesions are often considered suitable for surgery. Complete removal of the lesion and the ictal onset zone are accepted as crucial for a favorable postoperative outcome. A significant portion of the lesions extends into juxtacortical areas and is insufficiently recorded by superficial subdural grids.

Objective:

In our center depth electrodes (DE) were implanted into the lesions to achieve improved definition of the epileptogenic cortex in addition to subdural grid electrodes (SGE) since september 2009. We evaluated the feasibility, safety and diagnostic gain of this combined approach.

Methods:

395 patients underwent epilepsy surgery between 09/1998 and 01/2013 at the Epilepsy Center for Children and Adolescents, Schoen Klinik Vogtareuth. We present the retrospective data of 35 patients (f:12, m:23) since 09/2009 with invasive evaluation combining DE and SGE. DE and SGE were provided by Ad-Tech Corporation. Trajectories were planned using iPlan Cranial 2.6 software and DE were implanted using the VarioGuideTM system (BrainLAB AG). Electrodes were localised by post-implantation cMRI and cCT. Video-EEG monitoring was carried out for 10 days.

Results:

Etiology: FCD II in 21, tuberous sclerosis in 8 and tumors in 5 patients.

Age at onset of epilepsy: 2,6yrs (0.1 – 11), surgery: 10,2yrs (2,3 – 17), postoperative follow-up: 28 month (9 – 50).

Localization of epilepsy: frontal: 17, centro-parietal: 1, temporal: 6, temp.-par.-occ.: 5, other in 6 patient.

DE implantation hit all target areas; complications due to the DE were not observed.

Interictal epileptiform abnormalities were recorded: DE only: 4, DE & SGE: 26, SGE only: 5 patients, Ictal findings: DE only: 6, DE & SGE: 19, SGE only: 5 patients.

Post-surgical seizure outcome: seizure-free (Engel class 1a und b): 22, Engel class 2: 3, Engel class 3: 8, Engel class 4: 2 patients.

Conclusion:

Implantation of DE combined with SGE is safe and feasible. With the help of DE, an improved spatial and temporal analysis of interictal and ictal findings is achieved. By complementing brain convexity data, DE add valuable information required for appropriate resection planning.