Indications, Techniques, and Outcomes of Robot-Assisted Insular Stereo-Electro-Encephalography: A Review

Abstract

Stereo-electro-encephalography (SEEG) is an invasive, surgical, and electrophysiological method for three-dimensional registration and mapping of seizure activity in drug-resistant epilepsy. It allows the accurate analysis of spatio-temporal seizure activity by multiple intraparenchymal depth electrodes. The technique requires rigorous non-invasive pre-SEEG evaluation (clinical, video-EEG, and neuroimaging investigations) in order to plan the insertion of the SEEG electrodes with minimal risk and maximal recording accuracy. The resulting recordings are used to precisely define the surgical limits of resection of the epileptogenic zone in relation to adjacent eloquent structures. Since the initial description of the technique by Talairach and Bancaud in the 1950's, several techniques of electrode insertion have been used with accuracy and relatively few complications. In the last decade, robot-assisted surgery has emerged as a safe, accurate, and time-saving electrode insertion technique due to its unparalleled potential for orthogonal and oblique insertion trajectories, guided by rigorous computer-assisted planning. SEEG exploration of the insular cortex remains difficult due to its anatomical location, hidden by the temporal and frontoparietal opercula. Furthermore, the close vicinity of Sylvian vessels makes surgical electrode insertion challenging. Some epilepsy surgery teams remain cautious about insular exploration due to the potential of neurovascular injury. However, several authors have published encouraging results regarding the technique's accuracy and safety in both children and adults. We will review the indications, techniques, and outcomes of insular SEEG exploration with emphasis on robot-assisted implantation.

Keywords: SEEG (stereoelectroencephalography); epilepsy; epilepsy surgery planning; robot-assisted surgery (RAS)/computer assisted surgery (CAS); stereotaxic.

Figure 1

Example of ROSA-robot system in the operating room in Grenoble. (A) Five bone fiducials markers anchored in the patient skull in non-coplanar manner. (B) ROSA-robot system with sterile touchscreen easy to use interface and intraoperative CT. (C) ROSA-robot dedicated bone fiducials markers system for referencing process. (D) Immediate postoperative view of a right SEEG.

Figure 2

Neuromate-Robot system by Renishaw. (A,C) Neurolocate® system used for frameless registration. (B) Registration with Ultrasound technology. Images provided by RENISHAW with permission for publication (Renishaw-mayfield; Nyon, Switzerland).

Figure 3

Example of preoperative SEEG planning on ROSA software and postoperative MRI with mixed orthogonal and oblique trajectories. (A) 3D view of a left SEEG planning along with bone fiducials markers. (B) In plane view along oblique anterior insular (X) trajectory. (C) Example of SEEG planning fused with 3D angiography. (D) Postoperative sagittal T1 MRI with dark shadows representing electrodes with yellow dots superimposed representing planned trajectories. Note the oblique trajectories (X and Y) and four orthogonal trajectories (Q, R, S, and U). (E) Postoperative axial T1 MRI with dark shadows representing electrodes. Note the end location of contacts in the upper insula of orthogonal electrodes (R and S).