Stereo-Electro-Encephalo-Graphy (SEEG) With Robotic Assistance in the Presurgical Evaluation of Medical Refractory Epilepsy: A Technical Note

Summary

Stereo-electroencephalography (SEEG) aids in localization of epileptogenic zones, however, remains relatively underutilized in the United States. The goal of this abstract is to provide a brief introduction to the technique of SEEG and further a detailed technique of using robotic assistance in the placement of SEEG electrodes.

Abstract

SEEG is a method and technique which is used for accurate, invasive recording of seizure activity via three dimensional recordings. In epilepsy patients who are deemed appropriate candidates for invasive recordings, the decision to monitor is made between the subdural grids versus SEEG. Invasive neuromonitoring for epilepsy is pursued in patients with complex, medically refractory epilepsy. The goal of invasive monitoring is to offer resective surgery with the hope of allowing seizure freedom. SEEG's advantages include access to deep cortical structures, an ability to localize the epileptogenic zone (EZ) when subdural grids have failed to do so, and in patients with non-lesional extra-temporal epilepsies. In this manuscript, we present a succinct historical overview of the SEEG and report on our experience with frameless stereotaxy under robotic. An imperative step of SEEG insertion is planning the electrode trajectories. In order to most effectively record ictal activity via SEEG trajectories should be planned based upon a hypothesis of where the seizure activity originates the presumed epileptogenic zone (EZ). The EZ hypothesis is based on a standardized preoperative workup including video-EEG monitoring, MRI (magnetic resonance imaging), PET (positron emission tomography), ictal SPECT (Single-photon emission computed tomography), and neuropsychological assessment. Using a suspected EZ, SEEG electrodes can be placed minimally invasively yet maintain accuracy and precision. Clinical results showed the ability to localize the EZ in 78% of difficult to localize epileptic patients.¹

Introduction

In medically refractory epilepsy there are many non-invasive pre-surgical tools (scalp EEG., magnetic resonance imaging (MRI), functional MRI, single photon emission computed tomography, positron emission topography, and magnetoencephalography). If these non-invasive evaluations fail to sufficiently localize or define the epileptic zone (EZ) then invasive recording may be indicated. Currently, subdural grids or Stereo-electro-encephalo-graphy (SEEG) are the two most prevalent methods of invasive monitoring. SEEG was originally developed in France in the 1950's by Jean Talairach and Jean Bancaud; recently it has mostly been used for invasive monitoring of refractory ....

Protocol

Ethical statement: Our protocol follows the guidelines established by our institutional human research ethics committee.

1. Identification of Medically Refractory Epilepsy Patients

1. Prior to invasive monitoring, evaluate allpatientswith noninvasive techniques, such as video-EEG monitoring, MRI, PET, ictalSPECT, and neuropsychological studies as described in ¹ After discussion in multi-disciplinary meeting the decision whether or not to pursue invasive monitoring with SEEG must be made. ^1,6,7,11,14
2. Form a hypothesis regarding the location of the EZ. Develop a pre-implantation hypothesis of the presu....

Results

Recent results indicate that in one consecutive series of 78 patients who underwent SEEG insertion via robotic assistance had successful localization of the EZ in 76.2% of patients.¹ That same study showed of the patients who went on to have surgical resection of EZ had grade 1 Engel seizure freedom in 67.8% of patients (Figure 4). Morbidity rate is 2.5%. Permanent morbidity was noticed is 1 patient (1.2%). Per electrode, it was shown to have a wound infection .......

Discussion

Here is presented the technique of SEEG insertion utilizing robotic stereotactic assistance. While SEEG was originally described using other methods of frame based stereotaxis, robot-assisted SEEG offers not only similar safety but superior accuracy and efficiency. The literature reports success at localizing the EZ in over 76% of cases, which is commiserate with other previous studies using alternative techniques.^6,13,.

As with any invasive intracranial procedure, SEEG is not witho.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
ROSA	ROSA		robotic implantation system
electrodes	adtech