Transient Complete Resolution of Tourette Syndrome Symptoms Following Personalized Depth Electrode Placement

Treatment refractory Tourette syndrome has been shown to be improved with deep brain stimulation, but with multiple possible stimulation locations and variable and incomplete benefit. This study presents a single case of complete amelioration of motor and verbal tics in a patient with Tourette syndrome during placement of 12 stereo-EEG electrodes to identify optimal targets for permanent stimulating electrodes. Subsequently, substantial improvement in motor and verbal tic frequency occurred with placement and programming of permanent electrodes in bilateral globus pallidus internus and nucleus accumbens, but without the complete resolution seen during depth electrode placement. We suggest that simultaneous stimulation at multiple patient-specific targets could provide effective control of Tourette symptomatology, but further study will be needed.

Endonasal endoscopic surgery for temporal lobe epilepsy associated with sphenoidal encephalocele

Background: Temporal lobe epilepsy (TLE) associated with temporal lobe encephalocele is rare, and the precise epileptogenic mechanisms and surgical strategies for such cases are still unknown. Although the previous studies have reported good seizure outcomes following chronic subdural electrode recording through invasive craniotomy, only few studies have reported successful epilepsy surgery through endoscopic endonasal lesionectomy. Case Description: An 18-year-old man developed generalized convulsions at the age of 15 years. Despite treatment with optimal doses of antiepileptic drugs, episodes of speech and reading difficulties were observed 2–3 times per week. Long-term video electroencephalogram (EEG) revealed ictal activities starting from the left anterior temporal region. Magnetic resonance imaging revealed a temporal lobe encephalocele in the left lateral fossa of the sphenoidal sinus (sphenoidal encephalocele). Through the endoscopic endonasal approach, the tip of the encephalocele was exposed. A depth electrode was inserted into the encephalocele, which showed frequent spikes superimposed with high-frequency oscillations (HFOs) suggesting intrinsic epileptogenicity. The encephalocele was resected 8 mm from the tip. Twelve months postoperatively, the patient had no recurrence of seizures on tapering of the medication. Conclusion: TLE associated with sphenoidal encephalocele could be controlled with endoscopic endonasal lesionectomy, after confirming the high epileptogenicity with analysis of HFOs of intraoperative EEG recorded using an intralesional depth electrode.

Depth Electrode Guided Anterior Insulectomy: 2-Dimensional Operative Video

The insula is well established as an epileptogenic area.1 Insular epilepsy surgery demands precise anatomic knowledge2-4 and tailored removal of the epileptic zone with careful neuromonitoring.5 We present an operative video illustrating an intracranial electroencephalogram (EEG) depth electrode guided anterior insulectomy. We report a 17-yr-old right-handed woman with a 4-yr history of medically refractory epilepsy. The patient reported daily nocturnal ictal vocalization preceded by an indescribable feeling. Preoperative evaluation was suggestive of a right frontal-temporal onset, but the noninvasive results were discordant. She underwent a combined intracranial EEG study with a frontal-parietal grid, with strips and depth electrodes covering the entire right hemisphere. Epileptiform activity was observed in contact 6 of the anterior insula electrode. The patient consented to the procedure and to the publication of her images. A right anterior insulectomy was performed. First, a portion of the frontal operculum was resected and neuronavigation was used for the initial insula localization. However, due to unreliable neuronavigation (ie, brain shift), the medial and anterior borders of the insular resection were guided by the depth electrode reference. The patient was discharged 3 d after surgery with no neurological deficits and remains seizure free. We demonstrate that depth electrode guided insular surgery is a safe and precise technique, leading to an optimal outcome.

Accuracy and Workflow Improvements for Responsive Neurostimulation Hippocampal Depth Electrode Placement Using Robotic Stereotaxy

Background: Robotic stereotaxy is increasingly common in epilepsy surgery for the implantation of stereo-electroencephalography (sEEG) electrodes for intracranial seizure monitoring. The use of robots is also gaining popularity for permanent stereotactic lead implantation applications such as in deep brain stimulation and responsive neurostimulation (RNS) procedures.Objective: We describe the evolution of our robotic stereotactic implantation technique for placement of occipital-approach hippocampal RNS depth leads.Methods: We performed a retrospective review of 10 consecutive patients who underwent robotic RNS hippocampal depth electrode implantation. Accuracy of depth lead implantation was measured by registering intraoperative post-implantation fluoroscopic CT images and post-operative CT scans with the stereotactic plan to measure implantation accuracy. Seizure data were also collected from the RNS devices and analyzed to obtain initial seizure control outcome estimates.Results: Ten patients underwent occipital-approach hippocampal RNS depth electrode placement for medically refractory epilepsy. A total of 18 depth electrodes were included in the analysis. Six patients (10 electrodes) were implanted in the supine position, with mean target radial error of 1.9 ± 0.9 mm (mean ± SD). Four patients (8 electrodes) were implanted in the prone position, with mean radial error of 0.8 ± 0.3 mm. The radial error was significantly smaller when electrodes were implanted in the prone position compared to the supine position (p = 0.002). Early results (median follow-up time 7.4 months) demonstrate mean seizure frequency reduction of 26% (n = 8), with 37.5% achieving ≥50% reduction in seizure frequency as measured by RNS long episode counts.Conclusion: Prone positioning for robotic implantation of occipital-approach hippocampal RNS depth electrodes led to lower radial target error compared to supine positioning. The robotic platform offers a number of workflow advantages over traditional frame-based approaches, including parallel rather than serial operation in a bilateral case, decreased concern regarding human error in setting frame coordinates, and surgeon comfort.

Robotic Navigated Laser Craniotomy for Depth Electrode Implantation in Epilepsy Surgery: A Cadaver Lab Study

Objective Depth electrode implantation for invasive monitoring in epilepsy surgery has become a standard procedure. We describe a new frameless stereotactic intervention using robot-guided laser beam for making precise bone channels for depth electrode placement. Methods A laboratory investigation on a head cadaver specimen was performed using a CT scan planning of depth electrodes in various positions. Precise bone channels were made by a navigated robot-driven laser beam (erbium:yttrium aluminum garnet [Er:YAG], 2.94-μm wavelength,) instead of twist drill holes. Entry point and target point precision was calculated using postimplantation CT scans and comparison to the preoperative trajectory plan. Results Frontal, parietal, and occipital bone channels for bolt implantation were made. The occipital bone channel had an angulation of more than 60 degrees to the surface. Bolts and depth electrodes were implanted solely guided by the trajectory given by the precise bone channels. The mean depth electrode length was 45.5 mm. Entry point deviation was 0.73 mm (±0.66 mm SD) and target point deviation was 2.0 mm (±0.64 mm SD). Bone channel laser time was ∼30 seconds per channel. Altogether, the implantation time was ∼10 to 15 minutes per electrode. Conclusion Navigated robot-assisted laser for making precise bone channels for depth electrode implantation in epilepsy surgery is a promising new, exact and straightforward implantation technique and may have many advantages over twist drill hole implantation.