Frameless Robot-Assisted Asleep Centromedian Thalamic Nucleus Deep Brain Stimulation Surgery in Patients with Drug-Resistant Epilepsy: Technical Description and Short-Term Clinical Results.

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.

The accuracy of a novel self-tapping bone fiducial marker for frameless robot-assisted stereo-electro-encephalography implantation and registration techniques.

BACKGROUND: We aimed to evaluate the accuracy and safety of a novel self-tapping bone fiducial as a registration technique for stereoelectroencephalography (SEEG) implantation. METHODS: Each patient was installed with five bone fiducial markers. All procedures were performed using the same Sinovation robot system. The accuracy was determined by calculating the target point error (TPE) and the entry point error (EPE) of electrodes. RESULTS: Fourteen patients underwent SEEG implantation surgery; and the average installation time of the markers per patient was 86.1 s. In the operating theatre, the average registration time was 206.6 s, and the average registration error was 0.18 mm. The average TPE of 174 electrodes was 1.98 mm and the average EPE was 0.88 mm. CONCLUSION: Our study provided a bone fiducial marker installation and registration technique that was convenient and fast, highly accurate in registration, and highly tolerated by patients.

Case Report: Stereoelectroencephalography and Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation in Familial Lateral Temporal Lobe Epilepsy.

Familial lateral temporal lobe epilepsy (FLTLE) is genetic focal epilepsy usually characterised by auditory symptoms. Most FLTLE cases can be controlled by anti-seizure medications, and to our best knowledge, there are no previous reports about stereoelectroencephalography (SEEG) used for patients with FLTLE. In this report, we present two patients with FLTLE in one family and their SEEG performances, together with 18F-fluorodeoxyglucose (18F-FDG) PET and MRI results. In case 1, fast activities originated from the right superior temporal gyrus and spread rapidly to the right anterior insular lobe and hippocampus. In case 2, there were two seizure patterns: (1) The fast activities or sharp slow waves were identified at the left superior temporal gyrus, then, sharp waves and spike waves spread in the left superior temporal gyrus; (2) There were fast activities and slow-wave oscillation originated in the left superior temporal gyrus, then, the fast activities spread in the left superior temporal gyrus and finally spread to the other sites. An SEEG-guided radiofrequency thermocoagulation was performed for both patients and one of them underwent resection surgery. Seizures are well-controlled and the patients are very satisfied with the therapeutic effects.

Robot-Assisted Percutaneous Balloon Compression for Trigeminal Neuralgia: Technique Description and Short-Term Clinical Results.

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.

FreeSurfer and 3D Slicer-Assisted SEEG Implantation for Drug-Resistant Epilepsy.

Objective: Our study aimed to develop an approach to improve the speed and resolution of cerebral-hemisphere and lesion modeling and evaluate the advantages and disadvantages of robot-assisted surgical planning software. Methods: We applied both conventional robot planning software (method 1) and open-source auxiliary software (FreeSurfer and 3D Slicer; method 2) to model the brain and lesions in 19 patients with drug-resistant epilepsy. The patients' mean age at implantation was 21.4 years (range, 6-52 years). Each patient received an average of 12 electrodes (range, 9-16) between May and November 2021. The electrode-implantation plan was designed based on the models established using the two methods. We statistically analyzed and compared the duration of designing the models and planning the implantation using these two methods and performed the surgeries with the implantation plan designed using the auxiliary software. Results: A significantly longer time was needed to reconstruct a cerebral-hemisphere model using method 1 (mean, 206 s) than using method 2 (mean, 20 s) (p < 0.05). Both methods identified a mean of 1.4 lesions (range, 1-5) in each patient. Overall, using method 1 required longer (mean, 130 s; range, 48-436) than using method 2 (mean, 68.1 s; range, 50-104; p < 0.05). In addition, the clarity of the model based on method 1 was lower than that based on method 2. To devise an electrode-implantation plan, it took 9.1-25.5 min (mean, 16) and 6.6-14.8 min (mean, 10.2) based on methods 1 and 2, respectively (p < 0.05). The average target point error of 231 electrodes amounted to 1.90 mm ± 0.37 mm (range, 0.33-3.61 mm). The average entry point error was 0.89 ± 0.26 mm (range, 0.17-1.67 mm). None of the patients presented with intracranial hemorrhage or infection, and no other serious complications were observed. Conclusions: FreeSurfer and 3D Slicer-assisted SEEG implantation is an excellent approach to enhance modeling speed and resolution, shorten the electrode-implantation planning time, and boost the efficiency of clinical work. These well-known, trusted open-source programs do not have explicitly restricted licenses. These tools, therefore, seem well suited for clinical-research applications under the premise of approval by an ethics committee, informed consent of the patient, and clinical judgment of the surgeon.

Localization of the epileptogenic zone based on ictal stereo-electroencephalogram: Brain network and single-channel signal feature analysis.

Accurate localization of the epileptogenic zone (EZ) is crucial for refractory focal epilepsy patients to achieve freedom from seizures following epilepsy surgery. In this study, ictal stereo-electroencephalography data from 35 patients with refractory focal epilepsy were analyzed. Effective networks based on partial directed coherence were analyzed, and a gray level co-occurrence matrix was applied to extract the time-varying features of the in-degree. These features, combined with the single-channel signal time-frequency features, including approximate entropy and line length, were used to localize the EZ based on a cluster algorithm. For all seizure-free patients (n = 23), the proposed method was effective in identifying the clinical-EZ-contacts and clinical-EZ-blocks, with an F1-score of 62.47 % and 72.18 %, respectively. The sensitivity was 96.00 % for the clinical-EZ-block identification, which provided the information for the decision-making of clinicians, prompting clinicians to focus on the identified EZ-blocks and their nearby contacts. The agreement between the EZ identified by the proposed method and the clinical-EZ was worse for non-seizure-free patients (n = 12) than for seizure-free patients. Furthermore, our method provided better results than using only brain network or single-channel signal features. This suggests that combining these complementary features can facilitate more accurate localization of the EZ.

Multiphasic Side-Switching Seizures Are Easily Misdiagnosed as Unilateral Seizures During a Single EEG Monitoring Session: A Specific Subtype of Bitemporal Epilepsy.

BACKGROUND: Bitemporal epilepsy (BTLE) is a specific anatomoelectroclinical phenotype in the spectrum of temporal lobe epilepsy. The diagnosis of BTLE and the evaluation of the degree of seizure lateralization in BTLE patients are greatly influenced by the duration of EEG recording and the number of recorded habitual seizures. CASE DESCRIPTION: A 25-year-old woman had a 5-year history of seizures. Her habitual seizures were described as sudden behavioral arrest, staring, unresponsiveness, and oral automatisms, with auras of fear and palpitation. Intermittent scalp electroencephalography (EEG) and intracranial EEG monitoring over 3 years showed multiphasic side-switching seizures. The seizures were limited to 1 temporal lobe within 1 phase and switched sides between phases. Despite antiepileptic drugs and vagus nerve stimulation, her seizures remained uncontrolled. The patient finally underwent unilateral anteromedial temporal lobectomy, mainly based on >60% of seizures recorded originating from the left side. The patient has been seizure free for more than 1 year at last follow-up. CONCLUSIONS: This patient presented 1 specific subtype of BTLE that is prone to be misdiagnosed as unilateral temporal lobe epilepsy if the patient is recorded for a relatively short term, e.g., over a common EEG monitoring duration of 1 to 2 weeks.

Lead Failure After Vagus Nerve Stimulation Implantation: Radiographic Examination and Revision Surgery.

OBJECTIVE: The present study assessed the most common types of lead failures, identified the causes, and discussed the potential procedures for revision surgery after vagus nerve stimulator implantation in patients with epilepsy. METHODS: In a retrospective study during an 8-year period, 13 patients had undergone revision surgery because of lead failure. Lead failure was classified as either lead intrinsic damage or lead pin disengagement from the generator header. On the radiographic image, we defined a rear lead connector (RC) ratio that represented the portion of the rear lead connector in the header receptacle. It was used to quantitatively evaluate the mechanical failure of the lead-header interface. The optimal procedures to identify and manage lead failure were established. RESULTS: All 13 patients presented with high lead impedance of ≥9 kOhms at the time of revision. Of 10 patients with lead damage, 7 had presented with an increased seizure frequency after a period of seizure remission. In contrast to lead damage occurring relatively late (>15 months), lead pin disengagement was usually found within the early months after device implantation. A significant association was found between an elevated RC ratio (≥35%) and lead pin disengagement. The microsurgical technique permitted removal or replacement of the lead without adverse effects. CONCLUSIONS: The method of measuring the RC ratio developed in the present study is feasible for identifying lead disengagement at the generator level. Lead revision was an effective and safe procedure for patients experiencing lead failure.

Dynamic Network Connectivity Analysis to Identify Epileptogenic Zones Based on Stereo-Electroencephalography.

Objectives: Accurate localization of epileptogenic zones (EZs) is essential for successful surgical treatment of refractory focal epilepsy. The aim of the present study is to investigate whether a dynamic network connectivity analysis based on stereo-electroencephalography (SEEG) signals is effective in localizing EZs. Methods: SEEG data were recorded from seven patients who underwent presurgical evaluation for the treatment of refractory focal epilepsy and for whom the subsequent resective surgery gave a good outcome. A time-variant multivariate autoregressive model was constructed using a Kalman filter, and the time-variant partial directed coherence was computed. This was then used to construct a dynamic directed network model of the epileptic brain. Three graph measures (in-degree, out-degree, and betweenness centrality) were used to analyze the characteristics of the dynamic network and to find the important nodes in it. Results: In all seven patients, the indicative EZs localized by the in-degree and the betweenness centrality were highly consistent with the clinically diagnosed EZs. However, the out-degree did not indicate any significant differences between nodes in the network. Conclusions: In this work, a method based on ictal SEEG signals and effective connectivity analysis localized EZs accurately. The results suggest that the in-degree and betweenness centrality may be better network characteristics to localize EZs than the out-degree.

Localization of epileptogenic zone based on graph analysis of stereo-EEG.

Localization of the epileptogenic zone (EZ) is essential for the successful surgical treatment of medically intractable epilepsy. In the present study, stereo-EEG (SEEG) recordings were obtained from seven patients underwent presurgical evaluation for treatment of intractable epilepsy. Partial directed coherence (PDC) analysis was applied to construct peri-ictal effective connectivity networks. The graphic measures, in-degree, out-degree and betweenness centrality, were evaluated to localize the EZ. A receiver operating characteristic (ROC) analysis was used to quantify the localization accuracy. We found that the in-degree coincided well with the EZ identified by epileptologists' visual inspection in all seven patients who had a significant improvement in seizure outcomes, however, the other two measures were effective only in some cases. Furthermore, in all seven patients the electrode contact with the highest in-degree was always located within the EZ identified by epileptologists' visual inspection. These results indicate that the graph theory is an effective method to localize the EZ when suitable graphic measures were chosen. Furthermore, the in-degree was the most effective measure among the three graphic measures in localizing the EZ when the PDC method was used.

Economic burden of Parkinson's disease in a developing country: a retrospective cost analysis in Shanghai, China.

We investigated economic costs from patients with Parkinson's disease (PD) in Shanghai, China, which could be used as a baseline for future evaluations. Data were collected from 190 patients by interview during 1-year period. Direct medical care costs averaged approximately Chinese yuan, renminbi (RMB) 4,305 (USD 519, or EUR 410) per year per patient, of which drugs (RMB 2,677) accounted for the major costly component. Nonmedical direct costs were much less than direct health care costs, averaging approximately RMB 3,301 (USD 398, or EUR 314). Costs due to loss of productivity averaged approximately RMB 73 (USD 8.8, or EUR 7.0) per patient per year. Taken together, the overall mean annual cost for PD in our series was approximately RMB 7,679 (USD 925, or EUR 731), and these costs accounted for around half of the mean annual income. Total cost was significantly associated with the disease severity and the frequency of outpatient visits. In addition, levodopa equivalent dose (LED) and the number of drugs being taken were also closely related with the drug cost. The results indicate that the economic burden of Chinese PD patients is heavy.