Multinuclear thalamic targeting with human stereotactic electroencephalography

J Neurosurg 142:936–944, 2025

The study details a novel stereotactic electroencephalography (sEEG) approach targeting thalamic nuclei for personalized epilepsy treatment. It describes surgical techniques for sampling thalamic regions, aiming to improve neuromodulation strategies. The focus is on minimizing electrodes and maximizing cortical and subcortical coverage.

Multinuclear Thalamic Targeting with sEEG

• Novel sEEG approach identifies personalized seizure networks in the thalamus.

• Multilead orthogonal and trans-massa intermedia trajectories efficiently sample thalamic nuclei.

• Long-axis trajectory samples lateral PLV, MD, and ANT with a single electrode.

• Approaches resulted in no complications in 34 patients.

• Thalamic nuclei are crucial for neuromodulation in refractory epilepsy.

• DBS of thalamic nuclei shows heterogeneous patient responses.

Surgical Techniques and Trajectories

• Orthogonal trajectories maximize mediolateral thalamic coverage.

• Trans-massa intermedia approach samples bilateral MD nuclei with a single electrode.

• Long-axis trajectory samples ANT, MD, and PLV in a single plane.

• Extraventricular trajectories optimize thalamic coverage and safety.

Patient Selection and Outcomes

• 34 patients with drug-resistant epilepsy underwent sEEG implantation.

• Postoperative analysis showed millimetric accuracy in electrode placement.

• No thalamic hemorrhage or edema observed postoperatively.

A novel miniature robotic device for frameless implantation of depth electrodes in refractory epilepsy

J Neurosurg 126:1622–1628, 2017

The authors’ group recently published a novel technique for a navigation-guided frameless stereotactic approach for the placement of depth electrodes in epilepsy patients. To improve the accuracy of the trajectory and enhance the procedural workflow, the authors implemented the iSys1 miniature robotic device in the present study into this routine.

METHODS As a first step, a preclinical phantom study was performed using a human skull model, and the accuracy and timing between 5 electrodes implanted with the manual technique and 5 with the aid of the robot were compared. After this phantom study showed an increased accuracy with robot-assisted electrode placement and confirmed the robot’s ability to maintain stability despite the rotational forces and the leverage effect from drilling and screwing, patients were enrolled and analyzed for robot-assisted depth electrode placement at the authors’ institution from January 2014 to December 2015. All procedures were performed with the S7 Surgical Navigation System with Synergy Cranial software and the iSys1 miniature robotic device.

RESULTS Ninety-three electrodes were implanted in 16 patients (median age 33 years, range 3–55 years; 9 females, 7 males). The authors saw a significant increase in accuracy compared with their manual technique, with a median deviation from the planned entry and target points of 1.3 mm (range 0.1–3.4 mm) and 1.5 mm (range 0.3–6.7 mm), respectively. For the last 5 patients (31 electrodes) of this series the authors modified their technique in placing a guide for implantation of depth electrodes (GIDE) on the bone and saw a significant further increase in the accuracy at the entry point to 1.18 ± 0.5 mm (mean ± SD) compared with 1.54 ± 0.8 mm for the first 11 patients (p = 0.021). The median length of the trajectories was 45.4 mm (range 19–102.6 mm). The mean duration of depth electrode placement from the start of trajectory alignment to fixation of the electrode was 15.7 minutes (range 8.5–26.6 minutes), which was significantly faster than with the manual technique. In 12 patients, depth electrode placement was combined with subdural electrode placement. The procedure was well tolerated in all patients. The authors did not encounter any case of hemorrhage or neurological deficit related to the electrode placement. In 1 patient with a psoriasis vulgaris, a superficial wound infection was encountered. Adequate physiological recordings were obtained from all electrodes. No additional electrodes had to be implanted because of misplacement.

CONCLUSIONS The iSys1 robotic device is a versatile and easy to use tool for frameless implantation of depth electrodes for the treatment of epilepsy. It increased the accuracy of the authors’ manual technique by 60% at the entry point and over 30% at the target. It further enhanced and expedited the authors’ procedural workflow.

Robot-Assisted Stereoelectroencephalography

Robot-Assisted Stereoelectroencephalography

Neurosurgery 78:169–180, 2016

Robot-assisted stereoelectroencephalography (SEEG) may represent a simplified, precise, and safe alternative to the more traditional SEEG techniques.

OBJECTIVE: To report our clinical experience with robotic SEEG implantation and to define its utility in the management of patients with medically refractory epilepsy.

METHODS: The prospective observational analyses included all patients with medically refractory focal epilepsy who underwent robot-assisted stereotactic placement of depth electrodes for extraoperative brain monitoring between November 2009 and May 2013. Technical nuances of the robotic implantation technique are presented, as well as an analysis of demographics, time of planning and procedure, seizure outcome, in vivo accuracy, and procedure-related complications.

RESULTS: One hundred patients underwent 101 robot-assisted SEEG procedures. Their mean age was 33.2 years. In total, 1245 depth electrodes were implanted. On average, 12.5 electrodes were implanted per patient. The time of implantation planning was 30 minutes on average (range, 15-60 minutes). The average operative time was 130 minutes (range, 45-160 minutes). In vivo accuracy (calculated in 500 trajectories) demonstrated a median entry point error of 1.2 mm (interquartile range, 0.78-1.83 mm) and a median target point error of 1.7 mm (interquartile range, 1.20-2.30 mm). Of the group of patients who underwent resective surgery (68 patients), 45 (66.2%) gained seizure freedom status. Mean follow-up was 18 months. The total complication rate was 4%.

CONCLUSION: The robotic SEEG technique and method were demonstrated to be safe, accurate, and efficient in anatomically defining the epileptogenic zone and subsequently promoting sustained seizure freedom status in patients with difficult-to- localize seizures.