Operative Technique and Nuances for the Stereoelectroencephalographic (SEEG) Methodology Utilizing a Robotic Stereotactic Guidance System

Summary

The SEEG methodology is simplified and made faster with a stereotactic robot. Careful attention must be paid to the registration of the preoperative volumetric MRI to the patient prior to use of the robot in the OR. The robot streamlines the procedure, leading to decreased operative times and accurate implantations.

Abstract

The SEEG methodology has gained favor in North America over the last decade as a means of localizing the epileptogenic zone (EZ) prior to epilepsy surgery. Recently, the application of a robotic stereotactic guidance system for implantation of SEEG electrodes has become more popular in many epilepsy centers. The technique for the use of the robot requires extreme precision in the pre-surgical planning phase and then the technique is streamlined during the operative portion of the methodology, as the robot and surgeon work in concert to implant the electrodes. Herein is detailed precise operative methodology of using the robot to guide implantation of SEEG electrodes. A major limitation of the procedure, namely its heavy reliance on the ability to register the patient to a preoperative volumetric magnetic resonance image (MRI), is also discussed. Overall, this procedure has been shown to have a low morbidity rate and an extremely low mortality rate. The use of a robotic stereotactic guidance system for the implantation of SEEG electrodes is an efficient, fast, safe, and accurate alternative to conventional manual implantation strategies.

Introduction

Medically refractory epilepsy (MRE) is estimated to afflict fifteen million people world-wide¹. Many of these patients, therefore, may well be treated with surgery. Epilepsy surgery relies on the precise localization of the theorized epileptogenic zone (EZ) in order to guide surgical resections. Jean Tailarach and Jean Bancaud developed the stereoelectroencephalography (SEEG) methodology in the 1950s as a method for more accurately localizing the EZ based on the in situ electrophysiology of the epileptic brain in both cortical and deep structures^2,3. However, only recently has ....

Protocol

All devices used herein are FDA approved and the protocol contained herein constitutes the standard of care at our institution. As such, no IRB approval was needed for the detailing of this protocol.

1. Pre-implantation phase

1. Create an anatamo-electro-clinical (AEC) hypothesis.
   NOTE: Creation of the AEC hypothesis relies on the coordination of multiple non-invasive techniques for identifying the potential EZ. A team of experts, including epileptologists, radiologists, and epilepsy surgeons will typically convene a meeting to discuss the clinical data for each patient in order to create the AEC hypothesis, which serves as ....

Results

The absolute indicator of success following use of the SEEG methodology is seizure freedom for the patient, which ultimately follows successful electrode implantations, successful electrophysiological recordings, as well as successful resection of the EZ. Such a case is shown in Figure 1. Panels A and B of Figure 1 show two tests (single positron emission computed tomography (SPECT) and magnetoelectroencephalography (MEG), respec.......

Discussion

Meticulously defining of the AEC hypothesis coupled with particularly detailed attention to the design of the implantation strategy is ultimately what will determine the success of the SEEG methodology for each individual patient. As such, careful pre-surgical planning of the procedure is critical and makes for a relatively simple, low-risk surgery. Generally it is best to orient the trajectories orthogonally to the sagittal midline, thereby facilitating an easier anatomo-electrophysiological correlation in the future an.......

Materials

Name	Company	Catalog Number	Comments
2 mm drill bit	DIXI	KIP-ACS-510	For opening the cranium
Coagulation Electrode Dura	DIXI	KIP-ACS-600	for opening and coagulating the dura
Cordless driver	Stryker	4405-000-000	to drive the drill bit
Leksell Coordinate Frame G	Elekta	14611	For head fixation
Microdeep Depth Electrode	DIXI	D08-**AM	SEEG electrodes that are implanted, complete with: guide bolt and stylet, as described in manuscript.
ROSA	Medtech	n/a	stereotactic guidance system with robotic arm, complete with: robotic arm, calibration tool, registration laser, head frame attachment, and software, as described in the manuscript.
Stylet	DIXI	ACS-770S-10	for creating a path through the parenchyma for the electrode