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Non-invasive brain stimulation (NIBS), especially repetitive transcranial magnetic stimulation (rTMS), is a promising therapeutic tool for managing the psychiatric symptoms of Parkinson's disease (PD). This meta-analysis aims to assess the effect of NIBS on psychiatric symptoms in patients with PD.Several electronic databases were systematically searched for relevant literature from inception to October 18, 2021. The therapeutic effects of NIBS were evaluated using a random-effects meta-analysis based on the standard mean difference (SMD) and multivariable-adjusted effect estimates and subgroup analyses. Publication bias and sensitivity analyses were used to explore the sources of heterogeneity.Finally, 57 and 15 studies with 4,010 participants were obtained from the meta-analysis and systematic review, respectively. Significant differences were found between NIBS and sham-stimulation/placebo participants for depression (SMD = -0.75, 95 % confidence interval [CI]: -0.99 to -0.50, INIBS can be considered an effective non-pharmacological option for treating PD depression; moreover, rTMS combined with antidepressants was demonstrated to be a useful tool against depression and anxiety in PD.

Sampling the insulo-opercular region with invasive recordings is crucial given the importance of this region in epileptic networks and a variety of electroclinical presentations. However, implantation of the insulo-opercular region via stereoelectroencephalography (sEEG) is considered technically challenging given complex vascular and gray matter relationships in this region. We investigated the safety of insulo-opercular sEEG exploration in children and young adults using standard sEEG approaches: (1) orthogonal insulo-opercular (including the pseudo-orthogonal insulo-opercular approach) and (2) medial-lateral insular oblique approach.We performed a retrospective cohort study of 30 consecutive patients who underwent 33 sEEG implantations. All patients had drug-resistant focal epilepsy, were between the ages of 4 and 21, and were operated at one institution between January 2019 and March 2021. Medical records and neuroimaging were reviewed. Hemorrhage, infection, and other complications were considered as outcome variables.A total of 519 electrodes were placed. Eighty-one were placed orthogonally into the temporal operculum, 53 orthogonally into the frontal operculum, and 19 obliquely into the insula. sEEG electrodes localized seizure onset to the insulo-opercular region in eight patients, leading to a resection three times, an ablation four times, and one peri-insular hemispherectomy. Of the 519 electrodes placed, none of them exhibited hemorrhage or serious complications. Of the 153 electrodes placed into the insula, none had any permanent deficits or complications and one had minor bleeding due to the electrode breaking.These results demonstrate that the orthogonal (including pseudo-orthogonal) and medial approaches to sampling the insula are safe.

Surgery can cure or significantly improve both the frequency and the intensity of seizures in patients with medication-refractory epilepsy. The set of diagnostic and therapeutic interventions involved in the path from initial consultation to definitive surgery is complex and includes a multidisciplinary team of neurologists, neurosurgeons, neuroradiologists, and neuropsychologists, supported by a very large epilepsy-dedicated clinical architecture. In recent years, new practices and technologies have emerged that dramatically expand the scope of interventions performed. Stereoelectroencephalography has become widely adopted for seizure localization; stereotactic laser ablation has enabled more focal, less invasive, and less destructive interventions; and new brain stimulation devices have unlocked treatment of eloquent foci and multifocal onset etiologies. This article articulates and illustrates the full framework for how epilepsy patients are considered for surgical intervention, with particular attention given to stereotactic approaches.

Diffuse intrinsic pontine gliomas (DIPGs) are prone to high surgical risks, and they could even lead to death due to their specific sites. To determine the value of frameless robot-assisted stereotactic biopsies of DIPGs, when compared it with microsurgical biopsies.We conducted a retrospective study of 71 pediatric patients who underwent biopsies from January 2016 to January 2021. (i) group 1: microsurgical biopsies, and (ii) group 2: frameless robot-assisted stereotactic biopsies. Demographic information, neuroimaging characteristics, pathological diagnoses, operation time, postoperative intensive care unit (ICU) stay time, postoperative hospitalization time, complications, cost, and perioperative mortality rate (POMR) were collected for analyses.32 Cases underwent microsurgical biopsies (group 1) and 39 cases underwent frameless robot-assisted stereotactic biopsies (group 2). All cases were accurately diagnosed after surgery. There was no significant difference in gender, age, symptom times and tumor volumes between the two groups (p 0.05); operation time, postoperative ICU, stay time and postoperative hospitalization time were longer in group 1 than in group 2 (p 0.001); the intraoperative bleeding volumes and cost were higher in group 1 than in group 2 (p 0.001). Group 1 patients required more perioperative blood transfusion than group 2 (p = 0.001), and the new neurological impairments were more frequent in group 1 than in group 2 (p = 0.003). The POMR was 9.38% (3/32) in group 1 and 0 in group 2 (p = 0.087).Frameless robot-assisted stereotactic biopsy was an effective and minimally invasive technique for pediatric DIPGs.

To assess safety and long-term outcome of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC) of epileptic foci in eloquent motor areas.We retrospectively reviewed medical charts and surgical features of 15 patients with drug-resistant focal epilepsy in eloquent motor areas treated between 2017 and 2021. All patients underwent SEEG-guided RFTC as the first option. General characteristics, SEEG findings, morbidity, and seizure outcome after RFTC were analyzed to extract the potential value of SEEG-guided RFTC for epileptic foci in eloquent motor areas.There were 12 male and 3 female patients. Mean age at RFTC was 25 ± 8.5 years (range, 14-48 years), and mean duration of epilepsy before SEEG was 9.5 ± 7.0 years (range, 2-26 years). Mean follow-up period was 22.1 months (range, 8-41 months). Magnetic resonance imaging findings were negative in 2 cases, suspected focal cortical dysplasia in 10 cases, central region band heterotopias in 2 cases, and malformations of cortical development in 1 case. RFTC sites included primary precentral area (M1) (7, 46.7%), paracentral lobule (4, 26.7%), supplemental motor area (2, 13.3%), and premotor area (2, 13.3%). Of 15 patients, 12 (80%) experienced a ≥75% decrease in seizure frequency, of whom 9 (60%) experienced a long-term seizure-free period (10-29 months, mean 21.3 months). Three (20%) patients did not benefit from RFTC. Nine patients had neurological deficits immediately after RFTC (transient in 8 patients [3 days to 3 weeks] and prolonged in 1 patient).SEEG-guided RFTC for epileptic foci in eloquent motor areas seems to be a safe and effective procedure. It could be the first option for drug-resistant epilepsy that is not amenable to surgical resection, especially for extremally focused epileptic foci in the cortex close to or inside the central region. Larger series and prospective studies are necessary to validate our conclusions.

To study the effect of preoperative digital subtractive angiography (DSA) for planning stereoelectroencephalography (sEEG) electrode trajectories on the rate of postoperative radiographic hemorrhage.A retrospective, single-center observational study was conducted examining every sEEG implantation consisting of 72 implantations of 1028 total electrodes with each patient having received a preoperative planning DSA. Postimplant imaging was analyzed for the presence of hemorrhage. Postoperative computed tomography were then merged and coregistered with preoperative DSA to determine if a collision or near-miss (within 1 mm) occurred between the perihemorrhage electrodes and a vessel. Statistical analysis was then conducted.Six patients (8.3%) had hemorrhage seen on computed tomography with a bleeding rate of 0.6% per electrode. Five patients were asymptomatic (6.94%) and one symptomatic (1.39%). One patient suffered permanent neurologic deficits, and there have been zero deaths. In the hemorrhage group, there were 3 subdural, 2 subarachnoid, and 2 intraparenchymal. All subdural and subarachnoid hemorrhages had electrodes that were found to collide or near-miss a vessel when compared with preoperative DSA. Half of the intraparenchymal hemorrhages had no obvious vessel in proximity to the electrodes. Our data show that preoperative DSA is a viable screening test and portends a 94.7% sensitivity and 53.6% specificity for predicting post operative radiographic hemorrhage.Analysis of our sEEG series reveals a substantially lower rate of postimplant hemorrhage when compared with the recent cohort studies. Our data indicate that preoperative DSA may be efficacious in reducing the incidence of sEEG postimplant hemorrhages.

Stereotactic electroencephalography (SEEG) is an increasingly utilized method for invasive monitoring in patients with medically intractable epilepsy. Yet, the lack of standardization for labeling electrodes hinders communication among clinicians. A rational clustering of contacts based on anatomy rather than arbitrary physical leads may help clinical neurophysiologists interpret seizure networks. We identified SEEG electrodes on post-implant CTs and registered them to preoperative MRIs segmented according to an anatomical atlas. Individual contacts were automatically assigned to anatomical areas independent of lead. These contacts were then organized using a hierarchical anatomical schema for display and interpretation. Bipolar-referenced signal cross-correlations were used to compare the similarity of grouped signals within a conventional montage versus this anatomical montage. As a result, we developed a hierarchical organization for SEEG contacts using well-accepted, free software that is based solely on their post-implant anatomical location. When applied to three example SEEG cases for epilepsy, clusters of contacts that were anatomically related collapsed into standardized groups. Qualitatively, seizure events organized using this framework were better visually clustered compared to conventional schemes. Quantitatively, signals grouped by anatomical region were more similar to each other than electrode-based groups as measured by Pearson correlation. Further, we uploaded visualizations of SEEG reconstructions into the electronic medical record, rendering them durably useful given the interpretable electrode labels. In conclusion, we demonstrate a standardized, anatomically grounded approach to the organization of SEEG neuroimaging and electrophysiology data that may enable improved communication among and across surgical epilepsy teams and promote a clearer view of individual seizure networks.

As a pioneer center in the field of stereotaxy, Sainte-Anne school has always advocated the use of intraoperative imaging for stereotactic procedures to optimize both safety and accuracy. With the advent of intraoperative mobile CT unit, the robot-assisted stereotactic biopsy procedure has been recently updated.Herein, we aim at describing our new surgical procedure that combines robotic assistance (NeuroMate, Renishaw) and intraoperative cone beam CT imaging (O-Arm, Medtronic).Intraoperative imaging with the O-Arm was efficiently incorporated into the workflow. This new equipment leads to optimizing operative time and an easier realization of intraoperative imaging.

Objective Stereoelectroencephalography (SEEG) is a technique for preoperative evaluation of patients with difficult-to-localise refractory focal epilepsy (DLRFE), enabling the study of deep cortical structures. The procedure, which is increasingly used in international epilepsy centres, has not been fully developed in Spain. We describe our experience with SEEG in the preoperative evaluation of DLRFE. Material and methods In the last 8 years, 71 patients with DLRFE were evaluated with SEEG in our epilepsy centre. We prospectively analysed our results in terms of localisation of the epileptogenic zone (EZ), surgical outcomes, and complications associated with the procedure. Results The median age of the sample was 30 years (range, 4-59 years); 27 patients (38%) were women. Forty-five patients (63.4%) showed no abnormalities on brain MR images. A total of 627 electrodes were implanted (median, 9 electrodes per patient; range, 1-17), and 50% of implantations were multilobar. The EZ was identified in 64 patients (90.1%), and was extratemporal or temporal plus in 66% of the cases. Follow-up was over one year in 55 of the 61 patients undergoing surgery: in the last year of follow-up, 58.2% were seizure-free (Engel Epilepsy Surgery Outcome Scale class I) and 76.4% had good outcomes (Engel I-II). Three patients (4.2%) presented brain haemorrhages. Conclusion SEEG enables localisation of the EZ in patients in whom this was previously impossible, offering better surgical outcomes than other invasive techniques while having a relatively low rate of complications.

The ClearPoint SmartFrame Array (ClearPoint Neuro, Inc., Solana Beach, CA) system consists of a magnetic resonance imaging compatible frame supported by a customized neuro navigation software. This system received U.S. Food and Drug Administrationclearance for clinical use in January 2021. Our objective was to report initial safety data and user experience of SmartFrame Array-supported stereotactic procedures.We prospectively followed the first 10 consecutive patients who underwent stereotactic procedures supported by SmartFrame Array. Clinical and procedural data were recorded and compared to data obtained from prior cases with SmartFrame XG.Ten patients underwent stereotactic needle biopsy, stereotactic laser ablation (SLA), or combined biopsy/SLA procedures. For needle biopsies (n = 9), the average maximal diameter of the contrast-enhancing target lesion was 9.9 ± 2.8 mm. The radial error of stereotaxis was less than 2 mm. Definitive diagnosis was achieved in all cases. For procedures involving SLA (n = 5), 100% of the contrast-enhancing lesion was ablated. All patients were discharged home by postoperative day 2. There were no 30-day readmissions, morbidity, or mortality. The average stereotaxis time for the SmartFrame Array-aided single trajectory procedure was 80 ± 9.5 minutes, which compared favorably to that required for the earlier generation SmartFrame XG frame (111.5 ± 16.5 minutes; P0.01). The unique Array design supported stereotactic procedures that cannot be easily achieved with the previous SmartFrame XG frame.The SmartFrame Array system offers a more rigid and compact build to enhance procedural efficiency while maintaining accuracy and safety. The design supports multi-trajectory stereotaxis, allowing novel clinical applications.

The semiology of temporo-basal epilepsy has rarely been analysed in the literature. In this paper, we report three patients with proven basal temporal epilepsy with somatomotor or somatosensory facial ictal semiology, highly suggestive of insulo-opercular onset.The three patients had a temporobasal lesion and their drugresistant epilepsy was cured with resection of the lesion (follow-up duration: 7-17 years). We reviewed the medical charts, non-invasive EEG data as well as the stereoelectroencephalography (SEEG) performed in two patients. Quantitative analysis of ictal fast gamma activity was performed for one patient.Early ictal features were orofacial, either somatomotor in two patients or ipsilateral somatosensory in one. The three patients had prior sensations compatible with a temporal lobe onset. Interictal and ictal EEG pointed to the temporal lobe. The propagation of the discharge to the insula and operculum before the occurrence of facial features was seen on SEEG. Facial features occurred 7-20 seconds after electrical onset. Quantitative analysis of six seizures in one patient confirmed the visual analysis, showing statistically significant fast gamma activity originating from basal areas and then propagating to insuloopercular regions after a few seconds.We report three cases of lesional temporo-basal epilepsy responsible for orofacial semiology related to propagation of insulo-opercular ictal discharge. In MRI-negative patients with facial manifestations, this origin should be suspected when EEG is suggestive. These observations may contribute to our understanding of brain networks.

In recent years, thanks to several technological innovations, stereotactic cerebral biopsies have evolved from frame-based to frameless neuronavigation-assisted techniques.The authors provide herein a detailed step-by-step description of the technique, shedding light on surgical tips and how to avoid complications. The practical application of the technique is demonstrated with a high-quality video.The neuronavigation-assisted brain biopsy with electromagnetic tracking is a "true frameless" procedure. It represents a simple, safe, and effective innovation for frameless biopsy of cerebral lesions. This technique is time efficient, offering a high degree of accuracy required for the establishment of a definitive diagnosis, enabling optimal further treatment, and thus improving patient outcome.

The ROSA robot (Medtech) has been shown to be a useful instrument in the surgeon's armamentarium for accurate placement of stereotactic electroencephlography depth electrodes. However, it has not yet been used as a navigation tool for lesion resection. Here, we demonstrate a novel adapter that allows the surgeon to use the ROSA robot with the NICO BrainPath for the resection of deep lesions.To demonstrate the utility of an adapter that allows the ROSA robot to be used in conjunction with the NICO BrainPath tube for lesion resection.A stainless steel adapter was made based on the specifications of the ROSA pointer instrument. Two 3D printed models were used to undergo a "mock" surgery using the adapter to assess for ease of use and applicability.The adapter allowed for adequate accessibility and visualization of the tumors in both mock cases. In addition, the stability of the ROSA robot and the design of the adapter allowed the surgeon to rest their hands on the instrument without jeopardizing its position.The ROSA adapter allowed for accurate navigation and exposure of these lesions, combining the accuracy and stability of the ROSA robot, with the retraction of the BrainPath tube.

Colloid cysts are a group of CNS neoplasms that usually present with features of CSF flow obstruction. The treatment is by microsurgical, endoscopic or stereotactic techniques. Hydrocephalus usually resolves postoperatively, but in around 3-7% of cases symptoms persist and ultimately require CSF diversion. Several factors such as operative approach, cyst size, operative time, intraoperative bleeding may influence the need for CSF diversion but most of these are yet to be statistically proven. Existing literature is mainly focused on incidence of CSF diversion after resection of colloid cyst rather than the factors which may predict its necessity and extensive research is required to accurately determine these factors. Keywords: Colloid cyst, third ventricle, Cerebrospinal fluid diversion.

Objective. This study seeks to explore the efficacy and prognosis of stereotactic aspiration for malignant middle cerebral artery infarction (mMCAI). Methods. A total of 50 mMCAI patients who were diagnosed and treated in our hospital from January 2018 to June 2020 were collected and then randomly divided into control group (decompressive craniectomy, n = 24) and study group (stereotactic aspiration, n = 26). After 1 and 6 months of treatment, the scores of the National Institutes of Health Stroke Scale (NIHSS), Glasgow Coma Scale (GCS), Barthel Index, and modified Rankin Scale (mRS) were used to evaluate the therapeutic effect. Additionally, the mortality and survival rates after treatment were recorded to compare the prognostic effect between the two groups. Results. One month after treatment, the GCS scores and Barthel Index score increased in both the control and study groups and were significantly higher in the study group. The follow-up results at 1 and 6 months after treatment showed that in comparison with the control group, stereotactic aspiration led to a higher survival rate and lower mortality rate; the latter had superior NIHSS score and mRS score and better prognosis. Conclusion. In comparison with decompressive craniectomy, stereotactic aspiration shows outstanding clinical efficacy and more advantages in the treatment of mMCAI. Therefore, stereotactic aspiration is more worthy of clinical application.

Frameless stereotactic brain biopsy (FSB) with navigation system has been widely used. We reported preliminary experience of FSB with intraoperative computed tomography (iCT) and examined the usefulness of this novel adjuvant technique and real target registration error (rTRE) of FSB. The FSB with 5-aminolevulinic acid (5-ALA) and iCT was performed on 10 patients. The gadolinium-enhanced lesions on magnetic resonance image were defined as the biopsy target. In the procedure, iCTs were scanned twice, for autoregistration of the navigation system and for confirmation of the position of the actual inserted biopsy needle. The red fluorescence of the samples was observed under excitation with violet-blue light through a low-cut filter of neurosurgical microscope. The distance between the planned target and the tip of the biopsy needle in the image of iCT was calculated in a workstation for the assessment of rTRE. The median volume of the target was 12.13 mL (0.06-39.15 mL). We performed the surgical procedure in a prone position in four patients. None to faint 5-ALA-induced fluorescence was observed in six samples. There existed no sampling errors. The mean target distance between the planned and real targets of the mean rTRE of FSB was 2.7 ± 0.56 mm. The real TRE of FSB was first reported and was larger than the reported rTRE exactly calculated from the fiducial registration error. iCT guarantees accurate tumor sampling with autoregistration regardless of the surgical position and prevents inaccurate biopsy to occur even with ALA fluorescence assistance.

Multiple factors can affect the accuracy of neuronavigation, that is a relevant issue, particularly for frameless stereotactic procedures, where precision and optimal image-guidance is crucial for the surgical performance, workflow, and outcome.To investigate the impact of AIRO Mobile Computer Tomography in frameless stereotactic approaches.A retrospective study on 12 patients was performed. All the procedures were deployed using a frameless stereotactic technique, both for the collection of biopsy pathological specimens for diagnosis and insertion of drainage in the treatment of intracranial cystic lesions.Twelve patients (eight males, four females) underwent the frameless stereotactic procedure. Mean age at surgery was 55 (±5 SE). The mean volume of the lesion was 23.85 cmThe AIRO-CT resulted feasible with a potential utility for stereotactic procedures. We showed how it could grant the efficacy of the stereotactic procedures reducing some technical and physical sources of inaccuracy, also enhancing safety and allowing prompt detection and management of intraoperative complications.

OBJECTIVE One of the few resources for treating medically intractable pain is ablative surgery, but its indications have fallen dramatically over the last decades. One such procedure is mesencephalotomy. This study aims to determine current risks and benefits of MR-guided semidirect targeting–based stereotactic mesencephalotomy. METHODS This was a retrospective study based on a review of the medical records of 22 patients with nociceptive (n = 5), neuropathic (n = 10), or mixed (n = 7) refractory pain treated with unilateral mesencephalotomy alone (17 patients) or associated with bilateral anterior cingulotomy (5 patients) between 2014 and 2021 in the authors’ institutions. The confidence interval adopted in this study was 95%. RESULTS The sample included 12 women and 10 men with ages ranging from 23 to 80 years (mean 55.1 ± 17.1 years). Using MR-guided semidirect targeting, the following structures were targeted: spinoreticulothalamic (neuropathic/mixed pain, n = 17), trigeminothalamic (nociceptive/mixed pain in the face, n = 5), and neospinothalamic (nociceptive/mixed pain in the body, n = 7) pathways. The most common response to macrostimulation was central heat/moderate discomfort. Radiofrequency thermocoagulation was made with 70°C–75°C/60 sec. A total of 86.3% (3 months) and 76.9% (12 months) of the patients achieved excellent or good results (improvement of pain > 50%), presenting with a significant mean pain relief of 80.1% at 3 months and 71.4% at 12 months postoperatively. The addition of bilateral anterior cingulotomy did not improve the results. Patients with upper limb, cervicobrachial, and face pain did significantly better than those with trunk pain. The worst results were seen in patients with neuropathic and/or trunk pain. The surgical failure (pain relief ≤ 25%) and recurrence rates were 9.1% each, apparently related to the use of lower lesioning parameters (70°C/60 sec) and to the presence of neuropathic and/or trunk pain. The morbidity rate was 8%, with both complications (vertical diplopia and confusion/agitation) happening in patients lesioned with 75°C/60 sec. There were no deaths in this series. CONCLUSIONS These results show that contemporary stereotactic mesencephalotomy is an effective, relatively low-risk, and probably underused procedure for treating medically intractable pain. Careful semidirect determination of the target coordinates associated with close attention to electrical macrostimulation responses certainly plays an important role in avoiding complications in most of the procedures. A higher lesioning temperature (75°C) apparently prevents recurrence, but at the cost of an increased risk of complications.

Stereoelectroencephalography (SEEG) has become increasingly employed as a critical component of epilepsy workups for patients with drug-resistant epilepsy when information from noninvasive studies is not conclusive and sufficient to guide epilepsy surgery. Although exceedingly rare, clinically significant hemorrhagic complications can be caused during SEEG implantation procedures. Intracranial hemorrhage (ICH) can be difficult to recognize due to the minimally invasive nature of SEEG. The authors describe their technique using a commercially available intraparenchymal intracranial pressure (ICP) monitor as a method for early intraoperative detection of ICH during SEEG implantation. Between May 2019 and July 2021, 18 pediatric patients underwent SEEG implantation at a single, freestanding children’s hospital with the use of an ICP monitor during the procedure. No patients experienced complications resulting from this technique. The authors have relayed their rationale for ICP monitor use during SEEG, the technical considerations, and the safety profile. In addition, they have reported an illustrative case in which the ICP monitor proved crucial in early detection of ICH during SEEG implantation.

Stereoelectroencephalography (SEEG) is a minimally invasive surgical procedure, used to locate epileptogenic zones. An accurate identification of the metallic contacts recording the SEEG signal is crucial to ensure effectiveness of the upcoming treatment. However, due to the presence of metal, post-operative CT scans contain strong streak artefacts that interfere with deep learning segmentation algorithms and require a lot of training data to distinguish from actual contacts. We propose a method to generate synthetic data and use them to train a neural network to precisely locate SEEG electrode contacts.Random electrodes were generated following manufacturer's specifications and dimensions and placed in acceptable regions inside metal-free CT images. Metal artefacts were simulated in the generated data set using radon transform, beam hardening, and filtered back projection. A UNet neural network was trained for the contacts segmentation task using various training set-ups combining real data, basic augmented data, and synthetic data. The results were compared.We reported a higher accuracy when including synthetic data during the network training, while training only on real and basic augmented data more often led to misclassified artefacts or missed contacts. The network segments post-operative CT slices in less than 2 s using 4 GeForce RTX2080 Ti GPUs and in under a minute using a standard PC with GeForce GTX1060.Using synthetic data to train the network significantly improves contact detection and segmentation accuracy.

OBJECTIVE The literature shows discrepancies in stereotactic brain biopsy complication rates, severities, and outcomes. Little is known about the timeline of postbiopsy complications. This study aimed to analyze 1) complications following brain biopsies, using a graded severity scale, and 2) a timeline of complication occurrence. The secondary objectives were to determine factors associated with an increased risk of complications and to assess complication-related management and extra costs. METHODS The authors retrospectively examined 1500 consecutive stereotactic brain biopsies performed in adult patients at their tertiary medical center between April 2009 and April 2019. RESULTS Three hundred eighty-one biopsies (25.4%) were followed by a complication, including 88.2% of asymptomatic hemorrhages. Symptomatic complications involved 3.0% of the biopsies, and 0.8% of the biopsies were fatal. The severity grading scale had a 97.6% interobserver reproducibility. Twenty-three (51.1%) of the 45 symptomatic complications occurred within the 1st hour following the biopsy, while 75.6% occurred within the first 6 hours. Age ≥ 65 years, second biopsy procedures, gadolinium-enhanced lesions, glioblastomas, and lymphomas were predictors of biopsy-related complications. Brainstem biopsy-targeted lesions and cerebral toxoplasmosis were predictive of mortality. Asymptomatic hemorrhage was associated with delayed (> 6 hours) symptomatic complications. Symptomatic complications led to extended hospitalization in 86.7% of patients. The average extra cost for management of a patient with postbiopsy symptomatic complication was $35,702. CONCLUSIONS Symptomatic complications from brain biopsies are infrequent but associated with substantial adverse effects and cost implications for the healthcare system. The use of a severity grading scale, as the authors propose in this article, helps to classify complications according to the therapeutic consequences and the patient’s outcome. Because this study indicates that most complications occur within the first few hours following the biopsy, postbiopsy monitoring can be tailored accordingly. The authors therefore recommend systematic monitoring for 2 hours in the recovery unit and a CT scan 2 hours after the end of the biopsy procedure. In addition, they propose a modern algorithm for optimal postoperative management of patients undergoing stereotactic biopsy.

Background. The purpose of this study was to investigate the feasibility of the percutaneous radiofrequency (RF) excision system (BLES) as a primary method of diagnosis and removal of small breast masses. Methods. Ninety-six lesions in 95 patients with 50.5 ± 8.4 years of age were treated in a five-year period by a single operator. Inclusion criteria were as follows: size (10 mm), and indeterminate or suspicious radiological features (74 BI-RADS 3 and 22 BI-RADS 4). The procedure was performed under ultrasound (US) guidance using 6 G retriever probes with 12-, 15-, and 20-mm baskets. Results. Lesions were between 5 and 20 (12.3 ± 3.8) mm in length. They were removed at the first attempt in all but one case. The technical success rate was 98.95%, and the diagnostic success rate was 100%. Ninety-one lesions were histologically benign and five were neoplastic. Two lesions that were previously classified as BI-RADS 3 were diagnosed as neoplasia (atypical lobular hyperplasia), and nineteen lesions that were previously classified as BI-RADS 4a were diagnosed as benign. The complete excision rate (presence of tumor-free negative surgical margin) was 40% in neoplastic lesions. There were no major complications. The minor complication rate was 1.58%. No recurrence was observed during 18 months of follow-up. Conclusion. BLES delivers surgical quality specimens for confident histopathological examination and is a safe alternative to surgical resection in lesions with suitable size.

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous syndrome involved in many organ systems. At the same time, epilepsy is the most common manifestation and more than 50% of TSC patients present with intractable epilepsy. This study investigated the efficacy and safety of optimized and high-density stereoelectroencephalography (SEEG) guided radiofrequency thermocoagulation (RF-TC) in treating TSC-related epilepsy.Nine TSC children with refractory epilepsy were treated with first-stage SEEG-Guided RF-TC, and four underwent second-stage-optimized high-density array of SEEG-Guided RF-TC. Patients' clinical data and postoperative outcomes were analyzed retrospectively.The patients' median age at surgery was 4 years and 2 month (range from 3 years and 5 month to 16 years and 7 month). The mean age at surgery was 6.7 years old. Eight in 9 (88.9%) patients achieved complete remission after the final operation at half-year follow-up. Of seven patients with final postoperative time beyond 1 year, 6 (85.7%) reached completely seizure-free. No severe or long-term neurologic impairment existed in all nine patients.Optimized high-density array of SEEG-guided RF-TC is a safe and highly effective approach and can be an alternative application applied for TSC patients with refractory epilepsy.

Objective Noninvasive neural stimulation via temporally interferential (TI) electrical field is currently an area of interest as a noninvasive method of brain stimulation. The major limitation of TI stimulation is the difficulty of precise temporal control of the stimulation, due to the nature of the sinusoidal envelope generated by the interference. The purpose of this study was to investigate the possibility of improving interferential stimulation by introducing precise temporal control using phase modulation. Methods In conventional TI, a sinusoidal current is applied to two electrode pairs with slightly different frequencies, to cause interference. In this paper we describe phase modulation interference (PMI). Instead of shifting frequency, the phase of a sinusoidal wave was partially modulated, causing a transient increase or decrease of the envelope. The spatial distribution of envelope modulation amplitude by TI and PMI was visualized using both electromagnetic simulation and actual measurement using tissue phantom. Results The measured voltage transient in the tissue phantom produce a precise, temporally controlled pulse-like envelope using PMI. The spatial distributions of the amplitude of the envelope modulation by TI and PMI did not differ significantly, and were consistent with electromagnetic simulation. Conclusion PMI allows precise temporal control of interferential stimulation, thus increasing the practical utility of interferential stimulation. Significance PMI improves interferential stimulation, allowing more temporally precise stimulation to neural tissue located distantly from the stimulating electrodes.

A 12-year long, prospective, single center study was conducted, comparing two frameless systems for brain biopsies: ROSA robotic-assisted stereotaxy and BrainLab Varioguide image-guided stereotaxy (Image Guided Surgery, IGS).All consecutive adult and pediatric patients undergoing frameless brain biopsies were included. Successfully achieving diagnosis was the primary endpoint, analysis of all periprocedural complications was the secondary endpoint, and the tertiary endpoint was the length of the procedure, with the aim of assessing of the learning curve for each operator over time. The results for the ROSA robot and the Varioguide system were compared and benchmarked to data from the literature.We performed 526 on 516 patients, 314 with the ROSA robot (Group A) and 212 with the IGS Varioguide (Group B). Histological diagnosis was achieved in 97.4% of cases in Group A, versus 93.3% in Group B (p 0.05). No statistically significant difference was found for secondary and tertiary endpoints. The complication rate appeared similar between the 2 frameless systems, with a hemorrhagic complications rate of 3.5% in Group A and 4.7% in Group B. Permanent neurological deterioration was only recorded in 0.8% of cases from Group B. Mortality was recorded in 0.3% in Group A and 0.4% in Group B.This study provides evidence to confirm that robotic surgery lives up to its promises of increased safety, accuracy, and reliability.

The common marmoset has emerged as a popular model in neuroscience research, in part due to its reproductive efficiency, genetic and neuroanatomical similarities to humans and the successful generation of transgenic lines. Stereotaxic procedures in marmosets are guided by 2D stereotaxic atlases, which are constructed with a limited number of animals and fail to account for inter-individual variability in skull and brain size. Here, we developed a frameless imaging-guided stereotaxic system that improves upon traditional approaches by using subject-specific registration of computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) data to identify a surgical target, namely the putamen, in two marmosets. The skull surface was laser-scanned with to create a point cloud that was registered to the 3D reconstruction of the skull from CT. Reconstruction of the skull, as well as of the brain from MR images, was crucial for surgical planning. Localisation and injection into the putamen was done using a 6-axis robotic arm controlled by a surgical navigation software (BrainsightTM). Integration of subject-specific registration and frameless stereotaxic navigation allowed target localisation specific to each animal. Injection of alpha-synuclein fibrils into the putamen triggered progressive neurodegeneration of the nigro-striatal system, a key feature of Parkinson’s disease. Four months post-surgery, a PET scan found evidence of nigro-striatal denervation, supporting accurate targeting of the putamen during co-registration and subsequent surgery. Our results suggest that this approach, coupled with frameless stereotaxic neuronavigation, is accurate in localising surgical targets and can be used to assess endpoints for longitudinal studies.

Jean Talairach is world-renowned for his development of stereo-electroencephalography, and remains the most cited French neurosurgeon to date with his stereotactic atlas of the human brain. Zanello et al. explore the life of Jean Talairach, including his training as a psychiatrist and his military service during WW2.

Background: A wide range of techniques has been developed over the past decades to characterize amyloid-β (Aβ) pathology in mice. Until now, no method has been established to quantify spatial changes in Aβ plaque deposition due to targeted delivery of substances using ALZET® pumps. Objective: Development of a methodology to quantify the local distribution of Aβ plaques after intracerebral infusion of compounds. Methods: We have developed a toolbox to quantify Aβ plaques in relation to intracerebral injection channels using Zeiss AxioVision® and Microsoft Excel® software. For the proof of concept, intracerebral stereotactic surgery was performed in 50-day-old APP-transgenic mice injected with PBS. At the age of 100 days, brains were collected for immunhistological analysis. Results: The toolbox can be used to analyze and evaluate Aβ plaques (number, size, and coverage) in specific brain areas based on their location relative to the point of the injection or the injection channel. The tool provides classification of Aβ plaques in pre-defined distance groups using two different approaches. Conclusion: This new analytic toolbox facilitates the analysis of long-term continuous intracerebral experimental compound infusions using ALZET® pumps. This method generates reliable data for Aβ deposition characterization in relation to the distribution of experimental compounds.

Background Stereoelectroencephalography (sEEG) is an increasingly popular surgical technique used clinically to study neural circuits involved in medication-refractory epilepsy, and it is concomitantly used in the scientific investigation of neural circuitry underlying behavior. Methods Using PRISMA guidelines, the U.S. National Library of Medicine at the National Institutes of Health PubMed database was queried for investigational or therapeutic applications of sEEG in human subjects. Abstracts were analyzed independently by 2 authors for inclusion or exclusion. Results The study search identified 752 articles, and after exclusion criteria were applied, 8 studies were selected for in-depth review. Among those 8 studies, 122 patients were included, with indications ranging from schizophrenia to Parkinson disease. All the included studies were single-institution case series representing level IV scientific evidence. Conclusions sEEG is an important method in epilepsy surgery that could be applied to other neurologic and psychiatric diseases. Information from these studies could provide additional pathophysiologic information and lead to further development and refinement of neuromodulation therapies for such conditions.

Stereotactic brain biopsy is one of the most frequently performed brain surgeries. This review aimed to expose the latest cutting-edge and updated technologies and innovations available to neurosurgeons to safely perform stereotactic brain biopsy by minimizing the risks of complications and ensuring that the procedure is successful, leading to a histological diagnosis. We also examined methods for improving preoperative, intraoperative, and postoperative workflows. We performed a comprehensive state-of-the-art literature review. Intraoperative histology, fluorescence, and imaging techniques appear as smart tools to improve the diagnostic yield of biopsy. Constant innovations such as optical methods and augmented reality are also being made to increase patient safety. Robotics and integrated imaging techniques provide an enhanced intraoperative workflow. Patients' management algorithms based on early discharge after biopsy optimize the patient's personal experience and make the most efficient possible use of the available hospital resources. Many new trends are emerging, constantly improving patient care and safety, as well as surgical workflow. A parameter that must be considered is the cost-effectiveness of these devices and the possibility of using them on a daily basis. The decision to implement a new instrument in the surgical workflow should also be dependent on the number of procedures per year, the existing stereotactic equipment, and the experience of each center. Research on patients' postbiopsy management is another mandatory approach to enhance the safety profile of stereotactic brain biopsy and patient satisfaction, as well as to reduce healthcare costs.

Objective Stereoelectroencephalography (sEEG) is an intracranial encephalography method of expanding use. The need for increased epilepsy surgery access has led to the consideration of sEEG adoption by new or expanding surgical epilepsy programs. Data regarding safety and efficacy are uncommon outside of high‐volume, well‐established centers, which may be less applicable to newer or low‐volume centers. The objective of this study was to add to the sEEG outcomes in the literature from the perspective of a rapidly expanding center. Methods A retrospective chart review of consecutive sEEG cases from January 2016 to December 2019 was performed. Data extraction included demographic data, surgical data, and outcome data, which pertinently examined surgical method, progression to therapeutic procedure, clinically significant adverse events, and Engel outcomes. Results One hundred and fifty‐two sEEG procedures were performed on 131 patients. Procedures averaged 10.5 electrodes for a total of 1603 electrodes. The majority (84%) of patients progressed to a therapeutic procedure. Six clinically significant complications occurred: three retained electrodes, two hemorrhages, and one failure to complete investigation. Only one complication resulted in a permanent deficit. Engel 1 outcome was achieved in 63.3% of patients reaching one‐year follow‐up after a curative procedure. Significance New or expanding epilepsy surgery centers can appropriately consider the use of sEEG. The complication rate is low and the majority of patients progress to therapeutic surgery. Procedural safety, progression to therapeutic intervention, and Engel outcomes are comparable to cohorts from long‐established epilepsy surgery programs.

Objective This study assessed the short-term and the long-term breast cancer rate in patients with benign histopathologic results after a vacuum-assisted stereotactic biopsy (VASB) for calcifications. Methods In a retrospective cohort study, all consecutive patients who had a benign diagnosis after VASB to analyze breast calcifications. Data of breast cancer development at short-term (four years) and long-term follow-up was gathered. Breast cancer rates in our cohort were compared to the breast cancer incidence in the general population. Results Of 1376 patients who underwent VASB to analyze breast calcifications, 823 had a benign histopathologic diagnosis. During short-term follow-up, eight patients developed breast cancer. During the mean long-term follow-up period of 9.3 ± 3.1 years, 22 patients were diagnosed with ipsilateral breast cancer. The incidence rate of breast cancer after benign biopsy was comparable to the rate in the general population. Conclusion In patients with VASB-confirmed benign calcifications of the breast, we found no excess incidence of ipsilateral breast cancer during ten years follow-up. Therefore, in patients with an increased risk of breast cancer (due to a history of breast cancer or familial risk) annual mammography should be sufficient. Patients with a population-based risk may be monitored via biennial mammography by the national screening program. More frequent screening would provide no benefit., Highlights • 1% developed ipsilateral breast cancer in four-year follow-up after biopsy. • 3% developed ipsilateral breast cancer in ten-years follow-up after biopsy. • No statistically significant excess incidence of breast cancer after benign calcifications. • A benign histopathologic result after VASB can be considered a safe decision tool.

OBJECTIVE The safety of stereo-electroencephalography (SEEG) has been investigated; however, most studies have not differentiated pediatric and adult populations, which have different anatomy and physiology. The purpose of this study was to assess SEEG safety in the pediatric setting, focusing on surgical complications and the identification of patient and surgical risk factors, if any. The authors also aimed to determine whether robot assistance in SEEG was associated with a change in practice, surgical parameters, and clinical outcomes. METHODS The authors retrospectively studied all SEEG cases performed in their department from December 2014 to March 2020. They analyzed both demographic and surgical variables and noted the types of surgery-related complications and their management. They also studied the clinical outcomes of a subset of the patients in relation to robot-assisted and non–robot-assisted SEEG. RESULTS Sixty-three children had undergone 64 SEEG procedures. Girls were on average 3 years younger than the boys (mean age 11.1 vs 14.1 years, p < 0.01). The overall complication rate was 6.3%, and the complication rate for patients with left-sided electrodes was higher than that for patients with right-sided electrodes (11.1% vs 3.3%), although the difference between the two groups was not statistically significant. The duration of recording was positively correlated to the number of implanted electrodes (r = 0.296, p < 0.05). Robot assistance was associated with a higher number of implanted electrodes (mean 12.6 vs 7.6 electrodes, p < 0.0001). Robot-assisted implantations were more accurate, with a mean error of 1.51 mm at the target compared to 2.98 mm in nonrobot implantations (p < 0.001). Clinical outcomes were assessed in the first 32 patients treated (16 in the nonrobot group and 16 in the robot group), 23 of whom proceeded to further resective surgery. The children who had undergone robot-assisted SEEG had better eventual seizure control following subsequent epilepsy surgery. Of the children who had undergone resective epilepsy surgery, 42% (5/12) in the nonrobot group and 82% (9/11) in the robot group obtained an Engel class IA outcome at 1 year (χ2 = 3.885, p = 0.049). Based on Kaplan-Meier survival analysis, the robot group had a higher seizure-free rate than the nonrobot group at 30 months postoperation (7/11 vs 2/12, p = 0.063). Two complications, whose causes were attributed to the implantation and head-bandaging steps, required surgical intervention. All complications were either transient or reversible. CONCLUSIONS This is the largest single-center, exclusively pediatric SEEG series that includes robot assistance so far. SEEG complications are uncommon and usually transient or treatable. Robot assistance enabled implantation of more electrodes and improved epilepsy surgery outcomes, as compared to those in the non–robot-assisted cases.

Placing the patient in lateral position is an option for implantation of stereoelectroencephalography (SEEG) electrodes that have a posterior entry point. Previous studies reported the accuracy of SEEG electrodes but not specifically in relation to position. The aim of this study was to analyze accuracy of SEEG electrodes by position.Entry point and target accuracy of electrodes implanted in lateral position were compared with electrodes implanted in supine position using a frame-based with robot guidance technique. Subgroup analysis was performed for insular versus noninsular electrodes.Analysis included 23 consecutive patients (11 in lateral position) with 294 electrodes. The entry point error was similar between lateral (median 1.3 mm [interquartile range 0.8-1.9]) and supine (1.2 mm [0.8-1.7]; P = 0.360) position. Target accuracy was better in lateral (1.8 mm [1.3-2.7]) than supine (2.9 mm [2.0-4.4]; P0.001) position. For noninsular electrodes, the median entry point error in lateral and supine position was 1.3 mm (0.8-1.9) and 1.2 mm (0.8-1.7; P = 0.43), respectively. The accuracy was better in lateral position (median 1.7 mm [1.2-2.6]) compared with supine position (2.9 mm [2.0-4.4]; P0.001). The accuracy of insular electrodes was similar in both positions for entry point (lateral: median radial error 1.4 mm, [0.7-1.9]; supine: 1.1 mm [0.6-1.8]; P = 0.833) and target (lateral: median three-dimensional error 2.3 mm [1.6-3.2]; supine: 2.9 mm [2.4-4.5]; P = 0.07).SEEG leads implanted in lateral position exhibit an accuracy and safety profile in accordance with previous studies. In this cohort, target error was smaller in the lateral position, particularly in noninsular electrodes.

Background The brainstem has the critical role of regulating cardiac and respiratory function and it also provides motor and sensory function to the face via the cranial nerves. Despite the observation of a brainstem lesion in a radiological examination, it is difficult to obtain tissues for a pathological diagnosis because of the location and small volume of the brainstem. Thus, we aimed to share our 6‐year experience with stereotactic biopsies from brainstem lesions and confirm the value and safety of stereotactic biopsy on this highly eloquent area in this study. Methods We retrospectively reviewed the medical records of 42 adult patients who underwent stereotactic biopsy on brainstem lesions from 2015 to 2020. The radiological findings, surgical records, pathological diagnosis, and postoperative complications of all patients were analyzed. Results Histopathological diagnoses were made in 40 (95.2%) patients. Astrocytic tumors were diagnosed in 29 (69.0%) patients, diffuse large B cell lymphoma in 5 (11.9%) patients, demyelinating disease in 4 (9.5%) patients, germinoma in 1 (2.4%) patient, and radiation necrosis in 1 (2.4%) patient. In the 40 patients with successful stereotactic biopsy, 10 (25.0%) patients had inconsistent preoperative radiological diagnosis and postoperative pathological diagnosis. In addition, there was a difference between the treatments prescribed by the radiological and pathological diagnoses in 8 out of 10 patients whose diagnoses changed after biopsy. There was no operative mortality among the 42 patients. Conclusions A pathological diagnosis can be made safely and efficiently in brainstem lesions using stereotactic biopsy. This pathological diagnosis will enable patients to receive appropriate treatment., Three approaches to stereotactic biopsy for brainstem and a Venn diagram showing the location of 42 brainstem lesion that performed stereotactic biopsy.

Purpose Seizure originates from different pathological substrate; however, the same pathologies may have distinct mechanisms underlying seizure generation. We aimed to improve the understanding of such mechanisms in patients with temporal lobe epilepsy (TLE) by investigating the stereoelectroencephalography (SEEG) ictal onset patterns (IOPs). Methods We analyzed data from a cohort of 19 consecutive patients explored by SEEG and had 1–3-year seizure-freedom following temporal lobe resection. Results Six IOPs were identified. They were low voltage fast activity (LVFA) (36.5%), rhythmic spikes or spike-waves at low frequency and with high amplitude (34.1%), runs of spikes (10.6%), rhythmic sharp waves (8.2%), low frequency high amplitude repetitive spiking (LFRS) (7.1%), and delta activity (3.5%). All six patterns were found in patients with mesial temporal onset and only two patterns were found in patients with temporal neocortical onset. The most prevalent patterns for patients with mesial temporal onset were rhythmic spikes or spike-waves, followed by LVFA with a mean discharge rate 74 Hz. For patients with temporal neocortical onset, the most prevalent IOP pattern was LVFA with a mean discharge rate 35 Hz, followed by runs of spikes. Compared with Lateral TLE (LTLE), the duration between the onset of the IOPs to the onset of the symptom was longer for patients with MTLE (Mesial TLE) (MTLE:55.7 ± 50.6 s vs LTLE:19.5 ± 16.4 s). Conclusion Multiple IOPs underlie seizure generation in patients with TLE. However, the mesial and lateral temporal lobes share distinct IOPs.

We report a case of multiple brain abscesses' puncture, employing the ROSA™ Brain surgical robot (Zimmer Biomet) and the O-arm® O2 Imaging System (Medtronic). A 51-year-old man was diagnosed with multiple supratentorial ring enhancing cystic lesions consistent with brain abscesses. A neurological deterioration occurred despite broad spectrum antibiotic therapy, due to mass effect of the abscesses. Stereotactic aspiration was performed using the described technique, allowing a single stage puncture of the cerebral lesions. In this case, the robot-assisted and image-guided procedure permitted an accurate, quick, and efficient targeting of the multiple abscesses for drainage.

OBJECTIVE Electrophysiologic mapping (EM) has been instrumental in advancing neuroscience and ensuring accurate lead placement for deep brain stimulation. However, EM is associated with increased operative time, expense, and potential risk. Intraoperative imaging to verify lead placement provides an opportunity to reassess the clinical role of EM. We investigated whether EM 1) provides new information that corrects suboptimal preoperative target selection by the physician or 2) simply corrects intraoperative stereotactic error, which can instead be quickly corrected with intraoperative imaging. METHODS Deep brain stimulation lead location errors were evaluated by measuring whether repositioning leads based on EM directed the final lead placement 1) away from or 2) toward the original target. We retrospectively identified 50 patients with 61 leads that required repositioning directed by EM. The stereotactic coordinates of each lead were determined with intraoperative computed tomography. RESULTS In 45 of 61 leads (74%), the electrophysiologically directed repositioning moved the lead toward the initial target. The mean radial errors between the preoperative plan and targeted contact coordinates before and after repositioning were 2.2 and 1.5 mm, respectively (P < 0.001). Microelectrode recording was more likely than test stimulation to direct leads toward the initial target (88% vs. 63%; P = 0.03). The nucleus targeted was associated with the likelihood of moving toward the initial target. CONCLUSIONS Electrophysiologic mapping corrected primarily for errors in lead placement rather than providing new information regarding errors in target selection. Thus, intraoperative imaging and improvements in stereotactic techniques may reduce or even eliminate dependence on EM.

Diffusion tensor imaging (DTI) is an advanced imaging technique that helps to establish the topographic-anatomical relationship of tumours with the surrounding white matter tracts. Intra-operatively when used with neuro-navigation, it helps in minimizing injury to functional brain parenchyma, decreasing the risk of post-operative neurological deficits. In this review, we have assessed the efficacy of DTI for brain tumour resection.

Immunity is increasingly implicated in the aetiology of certain types of epilepsy, however, the clinical and EEG features in such cases remain poorly defined. We present stereo-electroencephalography (SEEG) findings in patients who were thought to have autoantibody-mediated epilepsy on the basis of clinical improvement after administration of immunotherapy (IT).All patients undergoing SEEG implantation in our service were reviewed and those receiving immunotherapy, either before, during, or after SEEG evaluation, were identified. Response to immunotherapy was defined as greater than 50% seizure reduction. We compared the clinical features and SEEG findings between those who responded to immunotherapy and those who did not.Sixty-two cases underwent SEEG evaluation. Of these, 11 received immunotherapy and three cases demonstrated a positive clinical benefit. The three responsive patients had multifocal seizure onset, repetitive spiking interictally and ictally, perisylvian semiology, seizure onset in the posterior perisylvian regions, and normal neuroimaging.Seronegative immunotherapy responders exist in epilepsy populations, therefore the diagnosis of autoimmune-associated epilepsy should be considered before proceeding to epilepsy surgery. Possible features of an electroclinical syndrome associated with autoimmunity may include multifocal seizure onset, perisylvian involvement, and normal neuroimaging.

Precise localization of the "epileptogenic zone(EZ)" is the goal of presurgical investigations in patients with drug-resistant focal epilepsy. Intracranial electroencephalography recordings are required when noninvasive evaluation results are not consistent. Although subdural grid electrodes(SDG)have been widely used in Japan, stereoelectroencephalography(SEEG)has been recently introduced. The principle of SEEG is based on anatomo-electro-clinical correlations to investigate surgical hypotheses that are primarily driven by the analysis of seizure semiology as well as other noninvasive investigations. The most important element of the SEEG methodology is to formulate preimplantation electrode trajectories considering the anatomo-electro-clinical correlations of epileptic seizures. If the preimplantation hypotheses are insufficient or incorrect, SEEG recordings will not identify the EZ. A detailed analysis of seizure semiology with respect to anatomo-electro-clinical correlates, particularly including various deep structures, such as the insular, operculum, and cingulate cortex, forms the basis of the implantation strategy for SEEG. The strategy of implantation is not to map the lobes/lobules but the epileptic networks, which usually involve multiple lobes, indicating that the theory of SEEG is completely different from that of SDG. Herein, we introduce the basics of SEEG, especially presurgical evaluations, with a representative case presentation.

This study models and investigates whether temporally interfering electric fields (TI EFs) could function as an effective non-invasive brain stimulation (NIBS) method for deep brain structure targeting in humans, relevant for psychiatric applications. Here, electric fields off- and on-target are modelled and compared with other common NIBS modalities (tACS, TMS). Additionally, local effects of the field strength are modelled on single-compartment neuronal models. While TI EFs are able to effectively reach deep brain targets, the ratio of off- to on-target stimulation remains high and comparable to other NIBS and may result in off-target neural blocks. Clinical Relevance— This study builds on earlier work and demonstrates some of the challenges -such as off-target conduction blocks- of applying TI EFs for targeting deep brain structures important in understanding the potential of treating neuropsychiatric conditions in the future.

Drug-resistant focal epilepsy presents a significant morbidity burden globally, and epilepsy surgery has been shown to be an effective treatment modality. Therefore, accurate identification of the epileptogenic zone for surgery is crucial, and in those with unclear noninvasive data, stereoencephalography is required.This review covers the history and current practices in the field of intracranial EEG, particularly analyzing how stereotactic image-guidance, robot-assisted navigation, and improved imaging techniques have increased the accuracy, scope, and use of SEEG globally.We provide a perspective on the future directions in the field, reviewing improvements in predicting electrode bending, image acquisition, machine learning and artificial intelligence, advances in surgical planning and visualization software and hardware. We also see the development of EEG analysis tools based on machine learning algorithms that are likely to work synergistically with neurophysiology experts and improve the efficiency of EEG and SEEG analysis and 3D visualization. Improving computer-assisted planning to minimize manual input from the surgeon, and seamless integration into an ergonomic and adaptive operating theater, incorporating hybrid microscopes, virtual and augmented reality is likely to be a significant area of improvement in the near future.

This study aimed to assess the benefit-risk ratio by determining diagnostic yield and safety of brainstem biopsies in adult patients. The secondary objectives were (i) to compare brainstem biopsy safety and postbiopsy patients' outcomes and survival with those of patients biopsied for a brain or cerebellar lesion, and (ii) to assess the impact of brainstem biopsy on final diagnosis and further therapeutic management.Among 1784 stereotactic biopsies performed in adult patients at a tertiary center between April 2009 and October 2020, we retrospectively examined 50 consecutive brainstem biopsies. We compared variables regarding diagnostic yield, safety and post-biopsy outcomes between brainstem biopsy patients and brain/cerebellum biopsy patients.Brainstem biopsy led to a diagnosis in 86% of patients (94.6% in patients with suspected tumor). Lesion contrast enhancement on imaging was the sole predictor of obtaining a diagnosis. Rates of symptomatic complications and mortality were significantly higher in brainstem biopsy patients compared to brain/cerebellum biopsy patients (20% vs 0%; p 0.001 and 6% vs 0%; p = 0.01, respectively). Transfrontal trajectory and prebiopsy swallowing disorders were predictors of brainstem biopsy-related symptomatic complications. Brainstem biopsy findings led to diagnostic change in 22% of patients.Stereotactic biopsy in adult patients with brainstem lesion has a high diagnostic yield. Although stereotactic brainstem biopsy is associated with more functional and fatal complications than biopsies targeting the brain/cerebellum, its safety profile appears acceptable. Thus, the benefit-risk ratio of stereotactic biopsy in patients with brainstem lesion is favorable but should nevertheless be carefully weighted on a case-by-case basis.

Describe our stereotactic brain biopsy (SBB) technique for intra-axial lesions of the posterior fossa, evaluate its effectiveness and safety, and compare them with other series.Retrospective study in ten consecutive patients, whose variables were age, gender, location of the lesions, clinical, radiological, and histopathological diagnoses, complications, and mortality, for analysis using descriptive statistics and tests of concordance and diagnostic validity.Lesions were pontine in seven cases, and pontomedullary in three occasions, with histopathological diagnoses of four Grade II astrocytomas, two Grade IV astrocytomas, two infectious process, one neuroblastic tumor, and one cavernous malformation, whose frequency differs from the previous reports (χThe SBB technique for posterior fossa implemented in our hospital shows high diagnostic yield, as well as absolute safety for the patient.Describir nuestra técnica de biopsia cerebral estereotáctica (SBB) para lesiones intraaxiales de fosa posterior, evaluar su eficacia y seguridad y compararlas con otras series.Estudio retrospectivo en 10 pacientes consecutivos, cuyas variables fueron edad, sexo, localización de las lesiones, diagnósticos clínicos, radiológicos e histopatológicos, complicaciones y mortalidad, para análisis mediante estadística descriptiva y pruebas de concordancia y validez diagnóstica.Las lesiones fueron pontinas en 7 casos y pontomedulares en 3 ocasiones, con diagnósticos histopatológicos de 4 astrocitomas grado II, 2 astrocitomas grado IV, 2 procesos infecciosos, 1 tumor neuroblástico y 1 malformación cavernosa, cuya frecuencia difiere de reportes previos (χLa técnica SBB para fosa posterior implementada en nuestro hospital muestra un alto rendimiento diagnóstico, así como una seguridad absoluta para el paciente.

The brain has the innate ability to undergo neuronal plasticity, which refers to changes in its structure and functions in response to continued changes in the environment. Although these concepts are well established in animal slice preparation models, their application to a large number of human subjects could only be achieved using noninvasive brain stimulation (NIBS) techniques. In this review, we discuss the mechanisms of plasticity induction using NIBS techniques including transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), random noise stimulation (RNS), transcranial ultrasound stimulation (TUS), vagus nerve stimulation (VNS), and galvanic vestibular stimulation (GVS). We briefly introduce these techniques, explain the stimulation parameters and potential clinical implications. Although their mechanisms are different, all these NIBS techniques can be used to induce plasticity at the systems level, to examine the neurophysiology of brain circuits and have potential therapeutic use in psychiatric and neurological disorders. TMS is the most established technique for the treatment of brain disorders, and repetitive TMS is an approved treatment for medication-resistant depression. Although the data on the clinical utility of the other modes of stimulation are more limited, the electrical stimulation techniques (tDCS, tACS, RNS, VNS, GVS) have the advantage of lower cost, portability, applicability at home, and can readily be combined with training or rehabilitation. Further research is needed to expand the clinical utility of NIBS and test the combination of different modes of NIBS to optimize neuromodulation induced clinical benefits.

Objective Stereoelectroencephalography (sEEG), despite its established usefulness, has not been thoroughly evaluated for its adverse events profile. In this study, hemorrhage rates were evaluated both per patient and per lead placed not only in the immediate postoperative period, but also over the course of admission and after explantation when available. Methods This is a single-center retrospective study of pediatric and adult patients undergoing sEEG lead placement at a large urban hospital. All available postoperative imaging was reviewed for the presence of hemorrhage, including any imaging occurring throughout admission as well as within 1 month of lead explantation. Age and number of leads placed per procedure were compared using an unpaired t test assuming unequal variance. Results A total of 1855 leads were placed in 147 cases. The mean age was 30.4 ±15.0 and the male/female ratio was 47:53. 9 leads (0.49%) in 9 cases (6.12%) were involved with postimplantation hemorrhage occurring on postoperative day 0.44 on average. Postexplantation imaging was available for 45 cases. Seven leads (1.40%) in 7 cases (15.56%) were involved with postexplantation hemorrhage occurring on average on postoperative day 1.42. There was a significant difference in mean age between patients with postexplantation hemorrhage versus control (45.0 vs. 32.2; P = 0.0277). No cases of hemorrhage required surgical intervention and no patients had permanent neurologic deficit. Conclusions Hemorrhage after sEEG lead implantation and explantation may be more common than previously reported. Consistent postexplantation imaging may be of clinical benefit in detecting hemorrhage that precludes patients from immediate discharge, particularly in older patients.

SUMMARY Electrical brain stimulation is an established therapy for movement disorders, epilepsy, obsessive compulsive disorder, and a potential therapy for many other neurologic and psychiatric disorders. Despite significant progress and FDA approvals, there remain significant clinical gaps that can be addressed with next generation systems. Integrating wearable sensors and implantable brain devices with off-the-body computing resources (smart phones and cloud resources) opens a new vista for dense behavioral and physiological signal tracking coupled with adaptive stimulation therapy that should have applications for a range of brain and mind disorders. Here, we briefly review some history and current electrical brain stimulation applications for epilepsy, deep brain stimulation and responsive neurostimulation, and emerging applications for next generation devices and systems.