Anatomical landmarks during high-magnification microsurgery for a safe and effective resection of high-grade gliomas: how I do it.

BACKGROUND: Gross total resection, when possible, is the first crucial treatment for high-grade gliomas, as it has been demonstrated to be associated with longer survival. Different intraoperative tools, such as neuronavigation, fluorescent agents, and intra-operative ultrasound, have been developed to help neurosurgeons to extend the resection. METHODS: We describe the high-magnification microsurgery technique used during the first surgical removal for high-grade gliomas. We illustrate the key anatomical "markers" of normal brain parenchyma, which guide the surgery. CONCLUSION: High-magnification microsurgery is an anatomically based approach that allows the identification of key anatomical "markers" of normal brain parenchyma in order to resect high-grade gliomas safely and effectively.

ATP-evoked intracellular Ca2+ transients shape the ionic permeability of human microglia from epileptic temporal cortex.

BACKGROUND: Intracellular Ca2+ modulates several microglial activities, such as proliferation, migration, phagocytosis, and inflammatory mediator secretion. Extracellular ATP, the levels of which significantly change during epileptic seizures, activates specific receptors leading to an increase of intracellular free Ca2+ concentration ([Ca2+]i). Here, we aimed to functionally characterize human microglia obtained from cortices of subjects with temporal lobe epilepsy, focusing on the Ca2+-mediated response triggered by purinergic signaling. METHODS: Fura-2 based fluorescence microscopy was used to measure [Ca2+]i in primary cultures of human microglial cells obtained from surgical specimens. The perforated patch-clamp technique, which preserves the cytoplasmic milieu, was used to measure ATP-evoked Ca2+-dependent whole-cell currents. RESULTS: In human microglia extracellular ATP evoked [Ca2+]i increases depend on Ca2+ entry from the extracellular space and on Ca2+ mobilization from intracellular compartments. Extracellular ATP also induced a transient fivefold potentiation of the total transmembrane current, which was completely abolished when [Ca2+]i increases were prevented by removing external Ca2+ and using an intracellular Ca2+ chelator. TRAM-34, a selective KCa3.1 blocker, significantly reduced the ATP-induced current potentiation but did not abolish it. The removal of external Cl- in the presence of TRAM-34 further lowered the ATP-evoked effect. A direct comparison between the ATP-evoked mean current potentiation and mean Ca2+ transient amplitude revealed a linear correlation. Treatment of microglial cells with LPS for 48 h did not prevent the ATP-induced Ca2+ mobilization but completely abolished the ATP-mediated current potentiation. The absence of the Ca2+-evoked K+ current led to a less sustained ATP-evoked Ca2+ entry, as shown by the faster Ca2+ transient kinetics observed in LPS-treated microglia. CONCLUSIONS: Our study confirms a functional role for KCa3.1 channels in human microglia, linking ATP-evoked Ca2+ transients to changes in membrane conductance, with an inflammation-dependent mechanism, and suggests that during brain inflammation the KCa3.1-mediated microglial response to purinergic signaling may be reduced.

Characteristics and management of hydrocephalus associated with vestibular schwannomas: a systematic review.

Hydrocephalus (HC) can be associated with vestibular schwannoma (VS) at presentation. Although spontaneous resolution of HC after VS removal is reported, first-line treatment is varied including preoperative ventriculoperitoneal (VP) shunt, external ventricular drainage (EVD), or lumbar drainage (LD). We performed a systematic review to clarify optimal management of HC associated with VS at presentation, as well as characteristics of patients with initial and persistent HC after VS removal, and prevalence of HC associated with VS. Fourteen studies were included. Patients were grouped according to the timing of HC treatment. The overall rate of VP shunts was 19.4%. Among patients who received VS removal as first-line treatment, 6.9% underwent permanent shunts. In a subgroup of 132 patients (studies with no-aggregate data), t test analysis for mean tumor size (P = 0.02) and mean CSF protein level (P < 0.001) demonstrated statistically significant differences between patients with resolved HC (3.48 cm and 201 mg/dL) and patients with persistent HC (2.46 cm and 76.8 mg/dL) after VS resection. Transient treatment of HC using EVD or LD further resolved the HC in 87.5% and 82.9% of patients, respectively, before and after VS removal. The overall prevalence of HC associated with VS in a population of 2336 patients was 9.3%. Schwannoma removal as first-line treatment is justified by its low rate of persistent HC requiring VP shunt (roughly 7%). Patients with smaller VS and lower CSF proteins present higher risk of persistent HC after schwannoma removal. Temporary treatment of HC contributes to its resolution, both before and after VS removal.

Hidden intra-meatal CSF fistula related to VP shunt as a cause for fatal tension pneumocephalus after vestibular schwannoma resection.

BACKGROUND: Cerebrospinal fluid (CSF) leak through petrosal air cells is a known complication after drilling the posterior wall of the internal acoustic canal (IAC) for resection of vestibular schwannoma (VS). Whereas mild pneumocephalus is common after retrosigmoid craniotomy, tension pneumocephalus has been rarely documented. OBJECTIVE: To testify a case of fatal tension pneumocephalus after VS resection in a patient with ventriculo-peritoneal (VP) shunt and to propose possible recommendations to limit the risk of this dramatic complication. METHODS: A case of fatal tension pneumocephalus after VS resection in presence of hidden CSF fistula is illustrated with pre- and post-operative images. RESULTS: In the uneventful situation of concomitant post-operative CSF fistula in presence of VP shunt, tension pneumocephalus may occur. The negative pressure created by the shunt system and the presence of osteo-dural defect allow the air to enter and, at the same time, prevent the outflow. CONCLUSION: After VS resection, tension pneumocephalus can occur as a consequence of CSF fistula from petrosal air cells in the presence of functioning VP shunt. Precautions as pre-operative increase to 'virtual-off' the pressure of the valve, subsequences CT scans after surgery and sealing of the petrous air cells are recommended to avoid such as fatal complication.

Long-term seizure outcome in frontal lobe epilepsy surgery.

PURPOSE: The purpose of this study was to report long-term seizure outcome in patients who underwent frontal lobe epilepsy (FLE) surgery. METHOD: This retrospective study included 44 consecutive subjects who underwent resective surgery for intractable FLE at IRCCS NEUROMED (period 2001-2014), followed up for at least 2 years (mean: 8.7 years). All patients underwent noninvasive presurgical evaluation and/or invasive electroencephalography (EEG) monitoring when nonconcordant data were obtained or epileptogenic zone was hypothesized to be close to the eloquent cortex. Electroclinical, neuroimaging, surgical data, and histology were compared to seizure outcome. RESULTS: Mean epilepsy duration was 19 years; mean age at surgery was 31.6 years. Preoperative magnetic resonance imaging (MRI) showed a frontal lesion in 86.4 % of cases. Scalp video-electroencephalography (VEEG) monitoring detected a focal ictal onset in 90% of cases. Twenty-seven patients (61.4%) underwent invasive recordings. Resections involved dorsolateral (47.7%), medial (9%), orbital (13.6%), and rolandic (13.6%) region. Lobectomy within functional boundaries was performed in the remaining 7 cases (16%). Transient and permanent neurological deficits were observed in 2 and 3 cases, respectively. Histology revealed focal cortical dysplasia (45.5%), World Health Organization (WHO) I-II grade tumors (15.9%), gliosis (22.7%), vascular malformations (4.5%), Rasmussen encephalitis (6.8%), and normal tissue (4.5%). At last observation 68.1% of patients were in Engel's class I, 11.4% in class II, 9% in class III, and 11.4% in class IV. A favorable outcome was associated with focal ictal scalp EEG onset (p = 0.0357). CONCLUSION: Surgery is a safe treatment option in drug-resistant FLE with a satisfying long-term outcome. These data highlight the importance of an appropriate selection of potential surgical candidates.

Loss of constitutive functional γ-aminobutyric acid type A-B receptor crosstalk in layer 5 pyramidal neurons of human epileptic temporal cortex.

OBJECTIVE: γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in adult central nervous system, and profound alterations of GABA receptor functions are linked to temporal lobe epilepsy (TLE). Here we describe the functional relationships between GABA receptors type B (GABAB R) and type A (GABAA R) in human temporal cortex and how TLE affects this aspect of GABAergic signaling. METHODS: Miniature inhibitory postsynaptic currents (mIPSCs) were recorded by patch-clamp techniques from human L5 pyramidal neurons in slices from temporal cortex tissue obtained from surgery. RESULTS: We describe a constitutive functional crosstalk between GABAB Rs and GABAA Rs in human temporal layer 5 pyramidal neurons, which is lost in epileptic tissues. The activation of GABAB Rs by baclofen, in addition to the expected reduction of mIPSC frequency, produced, in cortex of nonepileptic patients, the prolongation of mIPSC rise and decay times, thus increasing the inhibitory net charge associated with a single synaptic event. Block of K+ channels did not prevent the increase of decay time and charge. Protein kinase A (PKA) blocker KT5720 and pertussis toxin inhibited the action of baclofen, whereas 8Br-cAMP mimicked the GABAB R action. The same GABAB R-mediated modulation of GABAA Rs was observed in pyramidal neurons of rat temporal cortex, with both PKA and PKC involved in the process. In cortices from TLE patients and epileptic rats, baclofen lost its ability to modulate mIPSCs. SIGNIFICANCE: Our results highlight the association of TLE with functional changes of GABAergic signaling that may be related to seizure propagation, and suggest that the selective activation of a definite subset of nonpresynaptic GABAB Rs may be therapeutically useful in TLE.

Expression of Peroxisome Proliferator-Activated Receptor Alpha (PPARα) in Non-Somatotroph Pituitary Tumours and the Effects of PPARα Agonists on MMQ Cells.

Peroxisome proliferator-activated receptor alpha (PPARα) has been involved in the regulation of somatotroph tumour cells and may be targeted by different drugs, some of them are in current clinical use. The aim of this study was to investigate the expression of PPARα in additional phenotypes of pituitary adenomas (PA), the relationship between PPARα and its potential molecular partner aryl hydrocarbon receptor interacting protein (AIP) in these tumours, and the effects of PPARα agonists on lactotroph cells. Seventy-five human PA - 57 non-functioning (NFPA) and 18 prolactinomas (PRL-PA) - were characterised for PPARα and AIP expression by real time RT-PCR and/or immunohistochemistry (IHC), and the effects of fenofibrate and WY 14 643 on MMQ cells were studied in vitro. PPARα was expressed in a majority of PA. PPARα immunostaining was observed in 93.7% PRL-PA vs. 60.6% NFPA (p=0.016), the opposite being found for AIP (83.3% in NFPA vs. 43.7% in PRL-PA, p=0.003). PPARα expression was unrelated to gonadotroph differentiation in NFPA, but positively correlated with tumour volume in PRL-PA. Both drugs significantly reduced MMQ cell growth at high concentrations (100-200 µM). At the same time, despite modest stimulating effects on PRL secretion were observed, these were overcome by the reduction in cell number. In conclusion, PPARα is commonly expressed by PRL-PA and NFPA, regardless of AIP, and may represent a new target of PPARα agonists.

Clinical and Molecular Characteristics of Gonadotroph Pituitary Tumors According to the WHO Classification.

Since 2017, hormone-negative pituitary neuroendocrine tumors expressing the steroidogenic factor SF1 have been recognized as gonadotroph tumors (GnPT) but have been poorly studied. To further characterize their bio-clinical spectrum, 54 GnPT defined by immunostaining for FSH and/or LH (group 1, n = 41) or SF1 only (group 2, n = 13) were compared and studied for SF1, ßFSH, ßLH, CCNA2, CCNB1, CCND1, caspase 3, D2R, and AIP gene expression by qRT-PCR. Immunohistochemistry for AIP and/or D2R was performed in representative cases. Overall, patients were significantly younger in group 1 (P = 0.040 vs group 2), with a similar trend excluding recurrent cases (P = 0.078), and no significant difference in gender, tumor size, invasion or Ki67. SF1 expression was similar in both groups but negatively correlated with the patient's age (P = 0.013) and positively correlated with ßLH (P < 0.001) expression. Beta-FSH and AIP were significantly higher in group 1 (P = 0.042 and P = 0.024, respectively). Ki67 was unrelated to gonadotroph markers but positively correlated with CCNB1 (P = 0.001) and negatively correlated with CCND1 (P = 0.008). D2R and AIP were strongly correlated with each other (P < 0.001), and both positively correlated with SF1, ßFSH, ßLH, and CCND1. AIP immunopositivity was frequently observed in both groups, with a similar median score, and unrelated to Ki67. D2R immunostaining was best detected with a polyclonal antibody and mostly cytoplasmic. This study indicates that hormone-negative GnPT tend to occur in older patients but do not significantly differ from other GnPT in terms of invasion or proliferation. It also points out the current limits of D2R immunostaining in such tumors.

Surgery after intracranial investigation with subdural electrodes in patients with drug-resistant focal epilepsy: outcome and complications.

Video-EEG monitoring with intracranial subdural electrodes is a useful assessment tool for the localization of the epileptogenic zone in patients with drug-resistant focal epilepsy. We aimed at assessing the morbidity related to electrode implantation and the surgical outcome in patients who underwent epilepsy surgery after intracranial EEG monitoring. All patients (N = 58) admitted to our Epilepsy Surgery Centre for drug-resistant focal epilepsy who underwent resective surgery after intracranial monitoring with subdural electrodes and were followed up for at least 2 years were included in the study. Their mean age was 30.4 years (range 8-60 years), 25 (43 %) were female, and 44 (76 %) had a preoperatively detected structural lesion. The mean duration of invasive recording was 2.3 days (range 1-14 days). Extraoperative ECoG allowed the identification of the epileptogenic focus in all cases. The temporal lobe was involved in 21 (36 %) patients, whereas extratemporal foci were identified in 24 (41 %) patients. Thirteen patients (23 %) had multilobar involvement. Functional brain mapping was performed in 15 (26 %) patients. Transient complications related to electrode implantation occurred in three patients. Among patients with evidence of lesion on preoperative MRI, lesionectomy alone was performed in 12 cases (27 %), while it was combined with tailored cortical resection in the remaining cases. Tailored cortical resection was also performed in patients without evidence of lesion on MRI. After resective surgery, transient neurological deficits occurred in five cases, while another patient experienced permanent lateral homonymous hemianopia. At the last follow-up observation, 34 (57 %) patients were seizure-free (Engel class I). This study suggests that invasive EEG recording with subdural electrodes may be useful and fairly safe for many candidates for epilepsy surgery.

Blockage of A2A and A3 adenosine receptors decreases the desensitization of human GABA(A) receptors microtransplanted to Xenopus oocytes.

We previously found that the endogenous anticonvulsant adenosine, acting through A(2A) and A(3) adenosine receptors (ARs), alters the stability of currents (I(GABA)) generated by GABA(A) receptors expressed in the epileptic human mesial temporal lobe (MTLE). Here we examined whether ARs alter the stability (desensitization) of I(GABA) expressed in focal cortical dysplasia (FCD) and in periglioma epileptic tissues. The experiments were performed with tissues from 23 patients, using voltage-clamp recordings in Xenopus oocytes microinjected with membranes isolated from human MTLE and FCD tissues or using patch-clamp recordings of pyramidal neurons in epileptic tissue slices. On repetitive activation, the epileptic GABA(A) receptors revealed instability, manifested by a large I(GABA) rundown, which in most of the oocytes (approximately 70%) was obviously impaired by the new A(2A) antagonists ANR82, ANR94, and ANR152. In most MTLE tissue-microtransplanted oocytes, a new A(3) receptor antagonist (ANR235) significantly improved I(GABA) stability. Moreover, patch-clamped pyramidal neurons from human neocortical slices of periglioma epileptic tissues exhibited altered I(GABA) rundown on ANR94 treatment. Our findings indicate that antagonizing A(2A) and A(3) receptors increases the I(GABA) stability in different epileptic tissues and suggest that adenosine derivatives may offer therapeutic opportunities in various forms of human epilepsy.

Structural Brain Network Reorganization Following Anterior Callosotomy for Colloid Cysts: Connectometry and Graph Analysis Results.

Introduction: The plasticity of the neural circuits after injuries has been extensively investigated over the last decades. Transcallosal microsurgery for lesions affecting the third ventricle offers an interesting opportunity to investigate the whole-brain white matter reorganization occurring after a selective resection of the genu of the corpus callosum (CC). Method: Diffusion MRI (dMRI) data and neuropsychological testing were collected pre- and postoperatively in six patients with colloid cysts, surgically treated with a transcallosal-transgenual approach. Longitudinal connectometry analysis on dMRI data and graph analysis on structural connectivity matrix were implemented to analyze how white matter pathways and structural network topology reorganize after surgery. Results: Although a significant worsening in cognitive functions (e.g., executive and memory functioning) at early postoperative, a recovery to the preoperative status was observed at 6 months. Connectometry analysis, beyond the decrease of quantitative anisotropy (QA) near the resection cavity, showed an increase of QA in the body and forceps major CC subregions, as well as in the left intra-hemispheric corticocortical associative fibers. Accordingly, a reorganization of structural network topology was observed between centrality increasing in the left hemisphere nodes together with a rise in connectivity strength among mid and posterior CC subregions and cortical nodes. Conclusion: A structural reorganization of intra- and inter-hemispheric connective fibers and structural network topology were observed following the resection of the genu of the CC. Beyond the postoperative transient cognitive impairment, it could be argued anterior CC resection does not preclude neural plasticity and may subserve the long-term postoperative cognitive recovery.

Deep brain stimulation for Parkinson's disease in practice: results of the survey by the Italian Neurosurgery Society.

BACKGROUND: Deep brain stimulation (DBS) is a safe and effective treatment for patients with advanced Parkinson's disease (PD) and many neurosurgical centers in Italy have a DBS program. Considering the prevalence of PD and criteria for DBS implantation, about 3200-10,350 PD patients may benefit from DBS in Italy. The global management of patients underwent DBS is complex and it can be supposed that many differences exist between centers in clinical practice. The Italian Neurosurgery Society (SINch) designed this survey to investigate the state of the art of DBS for PD in Italy. METHODS: A 26-item closed-ended question survey was designed and sanded by email at all Italian Neurosurgery centers. The main topic investigated was DBS teams, anatomical target selection, surgical procedure, neuroimaging, intraoperative target localization, DBS device and patients' follow-up. RESULTS: A total of 23 neurosurgery centers completed the survey. There are mainly low-to medium-volume centers (<20 annual DBS procedures) with dedicated DBS teams. The principal anatomical target used is subthalamic nucleus (STN) and, relative to the surgical technique, it emerges that in Italy DBS are bilaterally implanted in a single-step session with awake anesthesia and with frame-based technique. Final leads positioning is defined by microelectrode recordings (MER) and microstimulation (MS), with limited role of intraoperative neuroimaging (MRI and O-Arm). The stimulation is started at 15 or 30 days from procedure. CONCLUSIONS: Many centers of neurosurgery in Italy have a well-established DBS program for patients with advanced PD and some practical differences in technique between centers exist. Further investigation is needed to investigate specific criteria for selecting one technique over another.

Multilevel Postoperative Cervical Epidural Hematoma: Complete Removal Through Catheter Drainage of the Unexposed Blood Collection.

BACKGROUND: Postoperative spinal epidural hematoma is a rare complication of anterior cervical discectomy and fusion. This condition may rapidly produce severe neurologic deficits, often requiring a prompt surgical decompression. A multilevel extension of the epidural bleeding has been rarely described after anterior cervical procedures. In such cases, the choice of the most suitable surgical approach may be challenging. Herein, we describe an effective surgical decompression of a C2-T1 ventral epidural hematoma following anterior cervical discectomy and fusion at the C5-C6 level. METHODS: By reopening the previous approach, the C5-C6 intersomatic cage was removed and the surgical field inspected for bleeding. After removal of the spinal epidural hematoma at this level, a lumbar external drainage catheter was inserted into the epidural space to perform multiple irrigations with saline solution until the washing fluid was clear. RESULTS: Immediate postoperative cervical computed tomography and magnetic resonance imaging revealed gross total removal of the epidural hematoma and complete decompression of the spinal cord all along the affected tract. Early postoperative neurologic examination revealed mild lower extremity weakness that fully recovered within hours. CONCLUSIONS: Although rare, multilevel epidural hematoma following anterior cervical decompression represents a serious complication. The revision of the previous anterior cervical approach may be considered the first treatment option, allowing to control the primary bleeding site. Catheter irrigation of the epidural space with saline solution may be a useful technique for removal of unexposed residual blood collection, avoiding the need for posterior laminectomy or other unnecessary bone demolition.

Pre-surgical fMRI Localization of the Hand Motor Cortex in Brain Tumors: Comparison Between Finger Tapping Task and a New Visual-Triggered Finger Movement Task.

Introduction: Pre-surgical mapping is clinically essential in the surgical management of brain tumors to preserve functions. A common technique to localize eloquent areas is functional magnetic resonance imaging (fMRI). In tumors involving the peri-rolandic regions, the finger tapping task (FTT) is typically administered to delineate the functional activation of hand-knob area. However, its selectivity may be limited. Thus, here, a novel cue-induced fMRI task was tested, the visual-triggered finger movement task (VFMT), aimed at eliciting a more accurate functional cortical mapping of the hand region as compared with FTT. Method: Twenty patients with glioma in the peri-rolandic regions underwent pre-operative mapping performing both FTT and VFMT. The fMRI data were analyzed for surgical procedures. When the craniotomy allowed to expose the motor cortex, the correspondence with intraoperative direct electrical stimulation (DES) was evaluated through sensitivity and specificity (mean sites = 11) calculated as percentage of true-positive and true-negative rates, respectively. Results: Both at group level and at single-subject level, differences among the tasks emerged in the functional representation of the hand-knob. Compared with FTT, VFMT showed a well-localized activation within the hand motor area and a less widespread activation in associative regions. Intraoperative DES confirmed the greater specificity (97%) and sensitivity (100%) of the VFMT in determining motor eloquent areas. Conclusion: The study provides a novel, external-triggered fMRI task for pre-surgical motor mapping. Compared with the traditional FTT, the new VFMT may have potential implications in clinical fMRI and surgical management due to its focal identification of the hand-knob region and good correspondence to intraoperative DES.

Bilateral epileptogenesis in temporal lobe epilepsy due to unilateral hippocampal sclerosis: A case series.

INTRODUCTION: Bitemporal epilepsy (biTLE), a potential cause of failure in TLE surgery, is rarely associated with unilateral HS and could be suggested by not lateralizing ictal scalp EEG/interictal PET-FDG findings. We evaluated the proportion of biTLE in a population of drug-resistant TLE-HS subjects who underwent intracranial investigation for lateralizing purpose. METHODS: We retrospectively included all consecutive refractory TLE-HS patients and not lateralizing ictal scalp EEG/interictal PET-FDG findings, investigated by intracranial bilateral longitudinal hippocampal electrodes. Demographic characteristics, electroclinical findings and seizure outcome were evaluated. RESULTS: We identified 14 subjects (7 males; mean age 39.5 years; mean age at disease onset 14.4 years), 7 of them had biTLE diagnosed after intracranial investigations. In the remaining 7 with unilateral epileptogenesis (uniTLE) anterior temporal lobectomy was performed (6/7 were in Engel class I). Preoperative neuropsychological assessment differentiated biTLE from uniTLE, as it was normal in six uniTLE patients but only in one with biTLE (p < 0.05). CONCLUSIONS: Not lateralizing ictal scalp EEG and functional imaging findings in TLEHS should alert about the possibility of a true biTLE also in presence of unilateral findings at MRI. Intracranial investigations with bilateral longitudinal hippocampal electrodes can localize the EZ with a good risk-benefit profile. Consistently with the warning on memory functions in TLE patients explored by using longitudinal hippocampal electrodes, further studies are needed to better define the optimal investigation strategy.

Efficient automated localization of ECoG electrodes in CT images via shape analysis.

PURPOSE: People with drug-refractory epilepsy are potential candidates for surgery. In many cases, epileptogenic zone localization requires intracranial investigations, e.g., via ElectroCorticoGraphy (ECoG), which uses subdural electrodes to map eloquent areas of large cortical regions. Precise electrodes localization on cortical surface is mandatory to delineate the seizure onset zone. Simple thresholding operations performed on patients' computed tomography (CT) volumes recognize electrodes but also other metal objects (e.g., wires, stitches), which need to be manually removed. A new automated method based on shape analysis is proposed, which provides substantially improved performances in ECoG electrodes recognition. METHODS: The proposed method was retrospectively tested on 24 CT volumes of subjects with drug-refractory focal epilepsy, presenting a large number (> 1700) of round platinum electrodes. After CT volume thresholding, six geometric features of voxel clusters (volume, symmetry axes lengths, circularity and cylinder similarity) were used to recognize the actual electrodes among all metal objects via a Gaussian support vector machine (G-SVM). The proposed method was further tested on seven CT volumes from a public repository. Simultaneous recognition of depth and ECoG electrodes was also investigated on three additional CT volumes, containing penetrating depth electrodes. RESULTS: The G-SVM provided a 99.74% mean classification accuracy across all 24 single-patient datasets, as well as on the combined dataset. High accuracies were obtained also on the CT volumes from public repository (98.27% across all patients, 99.68% on combined dataset). An overall accuracy of 99.34% was achieved for the recognition of depth and ECoG electrodes. CONCLUSIONS: The proposed method accomplishes automated ECoG electrodes localization with unprecedented accuracy and can be easily implemented into existing software for preoperative analysis process. The preliminary yet surprisingly good results achieved for the simultaneous depth and ECoG electrodes recognition are encouraging. Ethical approval n°NCT04479410 by "IRCCS Neuromed" (Pozzilli, Italy), 30th July 2020.

The Interhemispheric Transgenual Approach for Microsurgical Removal of Third Ventricle Colloid Cysts. Technical Note.

BACKGROUND: Colloid cysts of the third ventricle are rare benign lesions, which amount to approximately 1% of all intracranial tumors. Because these lesions grow predominantly in the anterior aspect of the third ventricle, they may cause the occlusion of the foramina of Monro, generating obstructive hydrocephalus. Surgery is mandatory in cases of large cysts and/or in symptomatic patients. Among the different surgical strategies described in colloid cysts surgery, the microsurgical transcallosal approach still constitutes the procedure of choice in many centers. In this study, we describe a modified microsurgical transcallosal approach, the interhemispheric transgenual approach, in a series of 13 consecutive patients operated on for colloid cysts of the third ventricle. METHODS: All the procedures were performed by the senior author (V.E.) at Neuromed Institute of Pozzilli (Is, Italy). The operative procedure is described in its various steps, illustrating the differences and potential advantages compared with the traditional microsurgical transcallosal approach. RESULTS: No surgical complications or new-onset neurologic deficits were observed in the postoperative period. The postoperative magnetic resonance imaging confirmed in all cases complete lesion removal without any sign of parenchymal damage. No lesion recurrence or need for permanent cerebrospinal fluid diversion was detected in the patients of this series during the follow-up period. CONCLUSIONS: In our experience, the interhemispheric transgenual approach has been effective in providing complete colloid cyst removal with minimal risk of vascular and parenchymal damage. Further studies are required to confirm its efficacy in improving the overall outcome of the microsurgical transcallosal approach.

Ictal Asystole in Drug-Resistant Focal Epilepsy: Two Decades of Experience from an Epilepsy Monitoring Unit.

BACKGROUND: Ictal asystole (IA) is a rare event observed in people with epilepsy (PwE). Clinical and IA video-electroencephalographic findings may be helpful in screening for high-risk subjects. Methods: From all PwE undergoing video-EEG for presurgical evaluation between 2000 and 2019, we retrospectively selected those with at least one IA (R-R interval of ≥3 s during a seizure). Results: IA was detected in eight out of 1088 (0.73%) subjects (mean age: 30 years; mean epilepsy duration: 9.6 years). Four out of them had a history of atonic falls. No patients had cardiac risk factors or cardiovascular diseases. Seizure onset was temporal (n = 5), temporo-parietal (n = 1) or frontal (n = 2), left-sided and right-sided in five and two patients, respectively. In one case a bilateral temporal independent seizure onset was recorded. IA was recorded in 11 out of 18 seizures. Mean IA duration was 13 s while mean IA latency from seizure onset was 26.7 s. Symptoms related to IA were observed in all seizures. Conclusion: IA is a rare and self-limiting event often observed during video-EG in patients with a history of atonic loss of consciousness and/or tardive falls in the course of a typical seizure.