SEEG, also known as stereoelectroencephalography, is a minimally invasive method of exploration of the human brain that takes into account the three-dimensional aspect of the epileptiform activity by analyzing the anatomoelectroclinical correlations. The main advantage of this method is to map epileptiform discharges in the brain in a minimally invasive fashion. Before beginning the SEEG procedure, help the patient into the supine position.
With the patient under general anesthesia, fix the patient's head in a three-point fixation holder and position the robot at the head of the patient such that the distance between the base of the robotic arm and the midpoint of the cranium is 70 centimeters. Lock the robot into position and secure the three-point head holder to the robot. Using the semi-automatic laser-based facial recognition system, register the pre-operative volumetric MRI with the patient, following all of the prompts given by the robot.
Use the set-distance calibration tool to calibrate the laser and use the laser to manually select the preset anatomical facial landmarks. After the robot automatically scans the facial surface, correlate additional independent surface landmarks with the registered MRI to confirm the accuracy of the registration. For bolt implantation, drape the patient in standard sterile fashion and drape the robotic working arm with sterile plastic.
Attach a drilling platform with a 2.5-millimeter working cannula to the robotic arm and select the desired trajectory for each bolt to be implanted on the touchscreen of the robot. Step on the robot pedal to initiate the movement of the robotic arm to the first trajectory. When the correct position is reached, the arm will be automatically locked by the robot.
Insert a two-millimeter drill through the working cannula and use it to create a pinhole through the entire thickness of the skull. Open the dura with an insulated dural perforator using monopolar cautery at a low setting. Screw the guide bolt firmly into each pinhole and use a sterile ruler to measure the distance from the drilling platform to the guide bolt.
Subtract this measured distance from the value of the distance platform-to-target used in planning the trajectory and record the result for later use as the final length of the implanted electrode. Measure and note the final length of the electrode and confirm that it matches the newly calculated length for the bolt. Then, give the electrode and bolt matching labels to prevent confusion during the electrode implantation.
When all of the bolts have been implanted, change surgical gloves and open a new sterile field. Insert a two-millimeter diameter stylet through a guide bolt to the intended depth of the electrode, as calculated after implantation of the matching bolt. Confirm that the electrode to be implanted matches the label of the implanted guide bolt and remove the stylet.
Immediately insert the electrode through the bolt and screw the electrode into the bolt for fixation, using fluoroscopic x-ray to confirm the correct placement of each electrode after it has been implanted. When all of the electrodes have been implanted, use a standard head bandaging technique to wrap the patient's head. Here, an appropriate operating room set up with a successful bolt placement and a successful electrode implantation for the SEEG methodology is shown.
Single positron emission computed tomography and magnetoelectroencephalography tests help in the creation of the anatomoelectroclinical hypothesis. In these representative images, an electrode was positioned in the frontal opercular and dorsal insular area. Here, a resection of the right operculum and insula in a post-operative T1 MRI is shown.
The SEEG method allows the three-dimensional mapping of the epileptiform activity by applying a minimally invasive technique of placing depth electrodes into the human brain.
