Jiwen Xu

Objective: Lennox–Gastaut syndrome (LGS) is generally regarded as a developmental and epileptic encephalopathy involving distributed brain networks, although a focal structural abnormality may occasionally recruit bilateral cortical and thalamic circuits and produce an LGS phenotype. We characterized the spatiotemporal organization of such a network and its changes after focal SEEG-guided radiofrequency thermocoagulation (RF-TC). Methods: A 50-year-old woman with drug-resistant epilepsy, multiple seizure types, diffuse slow spike-and-wave discharges, generalized paroxysmal fast activity, intellectual impairment, and right frontal periventricular heterotopia (PVH) underwent stereo-electroencephalography (SEEG). Cortico-cortical evoked potentials (CCEPs) were acquired before and after SEEG-guided radiofrequency thermocoagulation (RF-TC). Resting-state functional MRI (rs-fMRI), obtained before and 3 months after RF-TC, was analyzed using three seeds: the entire right frontal PVH and the right and left centromedian thalamic nuclei (CM). Results: SEEG identified the earliest sustained ictal activity within the sampled right frontal PVH-related medial contacts, accompanied by high-frequency activity. This was followed by ipsilateral lateral frontal recruitment, contralateral frontal synchronization, and subsequent bilateral CM involvement. Two-stage RF-TC of the onset and early-recruited networks was followed by seizure freedom through 9 months. After RF-TC, right-sided stimulation produced markedly attenuated lesion-related CCEP responses, whereas left-sided responses and responses between thalamic contacts showed little appreciable change. Descriptive rs-fMRI difference maps demonstrated decreased local frontal connectivity around the treated territory and increased long-range connectivity for the PVH seed; both CM seeds showed predominantly increased connectivity with distributed cortical and cerebellar regions. Conclusion: In this patient, a focal PVH-related epileptogenic network was associated with secondary bilateral cortical and thalamic recruitment underlying an LGS phenotype. CCEP and rs-fMRI captured complementary aspects of postoperative network change: attenuation of stimulation-evoked propagation and postoperative changes in intrinsic functional connectivity, respectively.

Epilepsy, a neurological disorder marked by recurrent, unprovoked seizures, is often linked to dysregulated iron metabolism, resulting in iron overload and subsequent cellular dysfunction or death within epileptogenic regions. We proposed a specific, noninvasive technique using paramagnetic susceptibility imaging via magnetic resonance imaging to quantify in vivo brain iron levels, aiming to enhance our understanding of epilepsy pathology and improve diagnostic accuracy. Our imaging and histopathological studies demonstrated that paramagnetic susceptibility is a sensitive biomarker for iron quantification in epilepsy. This method effectively detects iron abnormality from various causes and highlights that iron alters within epileptogenic zones, indicating the presence of potentially salvageable tissue. Furthermore, iron accumulation was observed to disrupt cortical laminar structures in epileptogenic zones and was associated with the proliferation of central nervous system cells, particularly astrocytes. Paramagnetic susceptibility imaging provides previously unknown insights into epilepsy, offering potential applications in diagnostics, monitoring, and personalized treatment strategies.

Non-invasive brain stimulation is promising for treating many neuropsychiatric and neurological conditions. It could be optimized by understanding its intracranial responses in different brain regions. We implanted multi-site intracranial electrodes and systematically assessed the acute responses in these regions to transcranial alternating current stimulation (tACS) at different frequencies. We observed robust neural oscillation changes in the hippocampus and amygdala in response to non-invasive tACS procedures, and these effects were frequency-specific and state-dependent. Notably, the hippocampus responded most strongly and stably to 10 Hz stimulation, with pronounced changes across a wide frequency range, suggesting the potential of 10 Hz oscillatory stimulation to modulate a broad range of neural activity related to cognitive functions. Future work with increased sample sizes is required to determine the clinical implications of these findings for therapeutic efficiency.

OBJECTIVE: Stylomastoid foramen (SMF) puncture with radiofrequency ablation (RFA) is a minimally invasive therapy for hemifacial spasm (HFS) with notable therapeutic outcomes. Conventionally, this procedure is performed under CT guidance. The present study highlights the authors’ preliminary clinical experience with robot-assisted SMF puncture in 7 patients with HFS using a neurosurgical robot. METHODS: Patients were secured in a skull clamp, and their heads were linked to the Sinovation neurosurgical robot’s linkage arms for precise positioning. Bone fiducial registration was conducted using the robotic pointer. Under robotic guidance, a puncture needle was positioned at the skin entry point and then advanced to the target with a surgical blade incision. On target attainment, an RFA electrode was positioned, and the ablation was performed while monitoring facial nerve function. Preoperative and postoperative spasm grading, surgical metrics, and adverse events were meticulously documented. RESULTS: The puncture trajectories averaged 49.5 mm in length, and the overall operation duration was 27.3 minutes. Guided by the robotic arm, all puncture attempts were successfully achieved without any obstructions, and SMF puncture was completed in a single attempt. Following RFA, immediate spasm relief was achieved, with all patients attaining Cohen spasm grade 0. Over a mean follow-up period of 12 months (range 6–15 months), no recurrence of spasms was reported. Facial paralysis was observed in 85.7% of patients, with 6 cases classified as House-Brackmann (HB) grade II and 1 case as grade III. At the final follow-up, 1 patient remained at HB grade II, while the remaining patients improved to grade I. No other lasting or severe complications were recorded. CONCLUSIONS: SMF puncture and RFA emerge as a potent and minimally invasive treatment option for HFS. The robot-assisted approach, despite necessitating additional time for head fixation and registration, notably reduces the overall puncture time, puncture attempts, and radiation exposure, thereby enhancing the puncture success rate.

Objective: Radiofrequency thermocoagulation (RFTC) has emerged as an effective and safe treatment method for patients with refractory focal epilepsy, when stereo‐electroencephalography (SEEG) is implanted. Although real‐world research results are still limited, a considerable number of patients have shown favorable outcomes with this less invasive method. This study aims to describe the outcomes and predictive factors of SEEG‐RFTC in real‐world research.Methods: A retrospective observational study was conducted on patients in the authors' epilepsy center. In total, 121 patients who underwent RFTC were included in the study. Post‐RFTC outcomes were evaluated using the seizure‐free rate and response rate (seizure frequency reduction more than 50%). Predictive factors influencing post‐RFTC outcome were considered by comparing different variables.Results: The mean follow‐up period was 18.3 months. Eighty‐two patients (67.8%) were responders and 54 (44.6%) were seizure free. In 36 patients with malformation of cortical development, the seizure‐free rate and the response rate were 69.44% and 83.33%, respectively. In 20 patients with hippocampal sclerosis, 19 patients were responders and 14 (70%) patients were seizure free at the last follow‐up. The MRI feature and etiology of epilepsy are correlated with the outcome. MR‐positive is a predictive factor for seizure freedom (p < 0.01) and responders (p < 0.01). Other factors have no predictive value for post‐RFTC outcome.Interpretation: SEEG‐RFTC is a safe procedure and yields favorable outcomes in numerous cases of focal DRE. The MRI feature and etiology of epilepsy are correlated with the seizure‐free rate and response rate. And MRI positivity is the predictor for good RFTC outcome.

Introduction This purpose of this work is to give a detailed description of a surgical technique for frameless robot-assisted asleep deep brain stimulation (DBS) of the centromedian thalamic nucleus (CMT) in drug-resistant epilepsy (DRE). Methods Ten consecutively enrolled patients who underwent CMT-DBS were included in the study. The FreeSurfer "Thalamic Kernel Segmentation" module and experience target coordinates were used for locating the CMT, and quantitative susceptibility mapping (QSM) images were used to check the target. The patient's head was secured with a head clip, and electrode implantation was performed with the assistance of the neurosurgical robot Sinovation^®. After opening the dura, the burr hole was continuously flushed with physiological saline to stop air from entering the skull. All procedures were performed under general anesthesia without intraoperative microelectrode recording (MER). Results The mean age of the patients at surgery and onset of seizures was 22 years (range 11–41 years) and 11 years (range 1–21 years), respectively. The median duration of seizures before CMT-DBS surgery was 10 years (2–26 years). CMT was successfully segmented, and its position was verified by experience target coordinates and QSM images in all ten patients. The mean surgical time for bilateral CMT-DBS in this cohort was 165 ± 18 min. The mean pneumocephalus volume was 2 cm³. The median absolute errors in the x-, y-, and z-axes were 0.7 mm, 0.5 mm, and 0.9 mm, respectively. The median Euclidean distance (ED) and radial error (RE) was 1.3 ± 0.5 mm and 1.0 ± 0.3 mm, respectively. No significant difference was found between right- and left-sided electrodes regarding the RE nor the ED. After a mean 12-month follow-up, the average reduction in seizures was 61%, and six patients experienced a ≥ 50% reduction in seizures, including one patient who had no seizures after the operation. All patients tolerated the anesthesia operation, and no permanent or serious complications were reported. Conclusions Frameless robot-assisted asleep surgery is a precise and safe approach for placing CMT electrodes in patients with DRE, shortening the surgery time. The segmentation of the thalamic nuclei enables the precise location of the CMT, and the flow of physiological saline to seal the burr holes is a good way to reduce the influx of air. CMT-DBS is an effective method to reduce seizures.

Objective: Percutaneous balloon compression (PBC) is a minimally invasive treatment for trigeminal neuralgia (TG) with a favorable cost-effectiveness ratio, but this technique has a steep learning curve. This study presents our initial clinical experience of robot-assisted PBC using a neurosurgical robot on six consecutive patients with TG.Methods: We fixed the patient's head with a skull clamp and connected it with the linkage arms of a Sinovation^® neurosurgical robot, which was then registered using four bone fiducials by the robotic pointer. The puncture needle was positioned at the entry point on the skin using a robotic arm and advanced to the target point after the skin had been incised with a pointed surgical blade. This procedure was repeated for a second trajectory. A balloon was then advanced and inflated using 0.3 ml of a contrast agent. Upon injection of 0.6 ml contrast agent, the ganglion was kept compressed for 120 s. After removal of the balloon and puncture needle, compression of the face was performed to achieve hemostasis.Results: All patients achieved immediate pain relief following PBC. No permanent or severe complications were registered, and there was no pain recurrence in any of the patients during the follow-up period.Conclusions: Despite requiring a longer time for preoperative preparation, robot-assisted PBC provided a high degree of accuracy and safety, and it can also shorten the learning curve for surgeons unfamiliar with PBC. Robot-assisted surgical approaches should be further developed and adopted for PBC.