Placement of Stereotactic Electroencephalography Depth Electrodes Using the Stealth Autoguide Robotic System: Technical Methods and Initial Results

Abstract

Background: Robotic systems are gaining acceptance as a preferred tool for the placement of electrodes for stereotactic electroencephalography (SEEG) studies.

Objective: To describe the technical methods for insertion of SEEG using the Medtronic Stealth Autoguide robotic system and detailed outcomes in the initial 9 patients implanted.

Methods: Nine patients underwent placement of electrodes for SEEG studies with the use of the Autoguide system. Patients had at least 10 electrodes placed. Targets were planned on a Stealth S8 planning station, and electrodes were placed under general anesthesia. A technique for placement is described in detail. Patient outcomes and accuracy of electrode placement were evaluated. Methods to improve accuracy were investigated. Comparison of postoperative MRIs with preoperative planning MRIs was performed to determine the accuracy of electrode placement.

Results: One hundred two electrodes were placed in 9 patients. Methods for placement and technical nuances are detailed. The distance from the planned target to the actual position of the electrode tip was measured in 8 of the 9 patients. The mean Euclidean distance was 4.67 ± 0.27 mm. There was 1 placement-related hemorrhage deficit in the first patient, and no deaths or infections. Adequate positioning of electrodes for seizure monitoring was obtained in all patients.

Conclusion: Autoguide can be used for placement of electrodes for SEEG studies with acceptable degrees of patient safety, accuracy, and efficiency. Considering the cost of Autoguide compared with other robotic devices, it may be attractive option.

FIGURE 1.

Intraoperative planning on the Medtronic StealthStation system with all 10 standard electrode plans pictured and 4 additional electrode plans based off of preoperative magnetoencephalography. ACC, anterior cingulate cortex; Amy, amygdala; Hipp, hippocampus; OF, orbitofrontal cortex; SMA, supplementary motor area.

FIGURE 2.

Diagram of the operating room setup with the Autoguide. The patient is rotated 180° from the anesthesiologist. The surgeon and assistant are at the patient's head with the scrub tech to the surgeon's right. By the patient's feet is the navigation system and tech, in easy view of the surgeon.

FIGURE 3.

A, Articulating arm of the Mayfield base is rotated so that the main axis of the arm is lateral, facilitating later use of the O-arm for radiographic confirmation of the electrode. B, Autoguide arm placement behind the patient for easy draping. The patient consented to publication of his/her image.

FIGURE 4.

Intraoperative O-arm images merged to preoperative MRI with plans overlaid. A, Coronal view with bilateral supplementary motor area plans, B, coronal view with bilateral anterior cingulate cortex plans, C, coronal view with bilateral amygdala plans, D, axial view with bilateral supplementary motor area plans, E, axial view with bilateral anterior cingulate cortex plans, and F, axial view with bilateral amygdala plans. Note that O-arm overlays are shown here for illustrative purposes, but actual errors between planned and final trajectories were measured by comparing plans from preoperative MRI with final electrode placements visualized on postoperative MRIs.