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Objective: This study aimed to evaluate the impact of augmented reality intraoperative fiber tractography (AR-iFT) on extent of resection (EOR), motor functional outcome, and survival of patients with primary motor area (M1) intra-axial malignant tumors., Methods: Data obtained from patients who underwent AR-iFT for M1 primary tumors were retrospectively analyzed and compared with those from a control group who underwent unaugmented reality intraoperative fiber tractography (unAR-iFT). A full asleep procedure with electrical stimulation mapping and fluorescein guidance was performed in both groups. The Neurological Assessment in Neuro-Oncology (NANO), Medical Research Council (MRC), and House-Brackmann grading systems were used for neurological, motor, and facial nerve assessment, respectively. Three-month postoperative NANO and MRC scores were used as outcome measures of the safety of the technique, whereas EOR and survival curves were related to its cytoreductive efficacy. In this study, p < 0.05 indicated statistical significance., Results: This study included 34 and 31 patients in the AR-iFT and unAR-iFT groups, respectively. The intraoperative seizure rate, 3-month postoperative NANO score, and 1-week and 1-month MRC scores were significantly (p < 0.05) different and in favor of the AR-iFT group. However, no difference was observed in the rate of complications. Glioma had incidence rates of 58.9% and 51.7% in the study and control groups, respectively, with no statistical difference. Metastasis had a slightly higher incidence rate in the control group, without statistical significance, and the gross-total resection and near-total resection rates and progression-free survival (PFS) rate were higher in the study group. Overall survival was not affected by the technique., Conclusions: AR-iFT proved to be feasible, effective, and safe during surgery for M1 tumors and positively affected the EOR, intraoperative seizure rate, motor outcome, and PFS. Integration with electrical stimulation mapping is critical to achieve constant anatomo-functional intraoperative feedback. The accuracy of AR-iFT is intrinsically limited by diffusion tensor-based techniques, parallax error, and fiber tract crowding. Further studies are warranted to definitively validate the benefits of augmented reality navigation in this surgical scenario.

Background and Objectives: Volumetric analysis of the working corridors of the interdural approach to the Meckel cave may lead to a selection of routes which are anatomically more advantageous for trigeminal schwannoma resection. The herein-reported anatomic study quantitively compares the infratrochlear (IT) transcavernous, anteromedial (AM), and anterolateral (AL) corridors, highlighting their feasibility, indications, advantages, and limitations., Methods: Anatomic boundaries and depth of Meckel cave, porus trigeminus, IT transcavernous, AM, and AL corridors were identified in 20 formalin-fixed latex-injected cadaveric heads and were subsequently measured. The corridor areas and volumes were derived accordingly. Each opening angle was also calculated. Angles and volumes were compared using analysis of variance. Statistical significance was set at a P -value <.05., Results: The IT transcavernous corridor volume was greater than that of the AM and AL. The opening angle of the AM middle fossa triangle was wider than the other 2., Conclusion: The IT corridor can be advantageous for Meckel cave schwannomas invading the cavernous sinus and those with a notable extension into the posterior fossa because the transcavernous approach maximizes the working space into the retrosellar area. The AM middle fossa corridor is strategic in schwannomas confined to the Meckel cave with a minor extension into the posterior fossa. It raises the chance of total resection with a single approach involving the porus trigeminus opening., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background: Recent studies suggest gliomas location may be correlated with specific biological signatures. Our purpose was to focus on the possible correlation between MGMT metilation status and Ki67 positivity with patient age, glioma location and lateralization., Methods: We performed a retrospective evaluation to assess the correlation between MGMT metilation status and Ki67 index positivity with patient age, glioma location and lateralization., Results: The study included 174 supratentorial gliomas. Of these, 144 tumors were high grade gliomas (HGGs), and 30 tumors were low grade gliomas (LGGs). In HGG group we detected an association between tumor location and MGMT status. Those GBMs located in the frontal lobe were significantly associated with MGMT methylated status (MGMT+) and Ki67<30% than those GBMs located in other sites; while those GBMs located in the temporal lobe were associated with MGMT unmethylated (MGMT-) status. In anaplastic gliomas, we found an association between the involvement of the frontal lobe with MGMT+ status and Ki67<30%. In LGG group, our results showed that both frontal and temporal lobe were associated with a Ki67<30% and there was a predictive value for MGMT methylation status when patient age increased., Conclusions: Our findings suggest there is a high variability in anatomical distribution of biological glioma markers and this high heterogeneity may have a clinical role. Moreover, our study supports the idea that frontal lobe HGGs may be biologically favorable. Considering that as all glioma with lobar location are more amenable to radical surgical resection, it may be assumed that frontal tumor can have a better prognosis, and we have shown, to our knowledge for the first time, this is true both for HGG and for LGG.

Introduction: Optic foraminotomy (OF) has been recently proposed as an alternative to anterior clinoidectomy (AC) for selected types of paraclinoid aneurysms. In this study, OF and AC were compared for small superior-projecting paraclinoid aneurysms assuming visual and angiographic results as outcome measures. Indications for OF are also discussed., Methods: Data of patients who underwent surgery for a paraclinoid aneurysm in the last 10 years were collected across 3 tertiary hospitals. Small to regular-size and superior projecting aneurysms were sorted. Multiple and complex aneurysms were excluded. Records of patients who went through OF were compared with those of patients who underwent AC. Neurologic outcome was reported as a modified Rankin Scale. Aneurysm complete occlusion rate and rate of approach-related worsened vision were selected as outcome measures of efficacy and safety, respectively, of the OF versus AC. Unpaired t test and χ 2 test were used for numerical and categorical variables, respectively. A P value less than 0.05 was considered statistically significant., Results: OF and AC groups involved 18 and 25 patients, respectively. Complication rate, overall neurologic outcome, rate of approach-related worsened vision, and complete occlusion rate did not differ between the groups. The average follow-up was 51 ± 34 and 60 ± 41 months in the OF and AC groups, respectively., Conclusions: Compared to AC, OF did not show either a higher rate of approach-related worsened vision or a lower aneurysm complete occlusion rate. OF can be considered a valid alternative to the AC for small superior-projecting dorsal ICA wall paraclinoid aneurysms., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Brain tumor surgery requires a delicate tradeoff between complete removal of neoplastic tissue while minimizing loss of brain function. Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have emerged as valuable tools for non-invasive assessment of human brain function and are now used to determine brain regions that should be spared to prevent functional impairment after surgery. However, image analysis requires different software packages, mainly developed for research purposes and often difficult to use in a clinical setting, preventing large-scale diffusion of presurgical mapping. We developed a specialized software able to implement an automatic analysis of multimodal MRI presurgical mapping in a single application and to transfer the results to the neuronavigator. Moreover, the imaging results are integrated in a commercially available wearable device using an optimized mixed-reality approach, automatically anchoring 3-dimensional holograms obtained from MRI with the physical head of the patient. This will allow the surgeon to virtually explore deeper tissue layers highlighting critical brain structures that need to be preserved, while retaining the natural oculo-manual coordination. The enhanced ergonomics of this procedure will significantly improve accuracy and safety of the surgery, with large expected benefits for health care systems and related industrial investors., (© 2022. The Author(s).)

The far lateral approach is an inferolateral extension of the lateral suboccipital approach. Designed for clipping of the aneurysms of the vertebrobasilar junction and proximal segments of the posterior inferior cerebellar artery, it became over the years a workhorse approach for ventral foramen magnum meningiomas and other intradural lesions located anterior to the dentate ligament.  This article summarizes the technical key aspects of the far lateral approach and transcondylar, supracondylar, and paracondylar extension.

The pterional approach is a workhorse in neurosurgery, to the point where perfect knowledge of its execution is essential in neurosurgical daily practice. The pterional transsylvian corridor is used to treat aneurysms involving anterior circulation, basilar apex, the proximal segment of the superior cerebellar and posterior cerebral artery, arteriovenous malformations and cavernous hemangiomas of the basal forebrain, anterior and middle skull base tumors, gliomas of the frontal, parietal, and temporal opercula, insula, mediobasal temporal region, cerebral peduncles, interpeduncular fossa, and also orbital lesions. We herein overview the core technique and variations of the pterional approach aimed at broadening surgical freedom and decreasing the risk of approach-related complications.

Introduction The interleukin-6 (IL-6), a proinflammatory cytokine, supports the adaptive immune response and regulates inflammatory processes. The -174 G>C and -572 G>C promoter polymorphisms of the IL-6 gene take part in the pathogenesis of intracranial aneurysms (IAs) and influence the clinical presentation of subarachnoid hemorrhage. This meta-analysis purposes to evaluate whether and which IL-6 allelic variations are related to a risk of IAs formation. Methods A PRISMA-based literature search was performed on the PubMed/Medline and Web of Science databases. The keywords used were "interleukin-6," "IL-6," "polymorphism," "interleukin-6 genotype," combined with "intracranial aneurysms" and "subarachnoid hemorrhage." Only human case-control studies, with a study (IAs) and a control group, written in English, and published in the last 15 years were selected. A meta-analysis was performed, estimating odds ratios and 95% confidence intervals in fixed- or random-effects models, as applicable. Statistical analysis was conducted with RevMan 5.0 software. Results 9 studies were eligible. No associations were found between -174 G>C polymorphisms and IAs susceptibility. Notable results were reported by the analysis of -572G>C polymorphisms. -572GG/GC/CC genotypes were strongly related to IAs occurrence with a statistical significance of p=0.03, p=0.0009, and p=0.00001, respectively. Conclusion A higher incidence of -572G>C promoter polymorphisms were demonstrated in the IAs group, highlighting the pivotal role of inflammatory genes in the natural history of brain aneurysms. Additional studies are required considering the racial heterogenicity and the need to widen the population sample.

Introduction Intracranial aneurysms (IAs) are devastating cerebrovascular diseases with multifactorial etiology. The role of inflammation is indisputable, and interleukins are pivotal in supporting local inflammatory pathways and endothelial dysfunction at the aneurysm wall. In the light of insufficient evidence reported in the literature, this meta-analysis was aimed to investigate the genetic linkage between IL-1β (rs16944) -511C>T polymorphisms and IAs susceptibility. Methods A comprehensive online literature review was completed using the PubMed/Medline and Web of Science databases in accordance with the PRISMA guidelines. "Interleukin-1β," "IL-1β," "polymorphism," "intracranial aneurysm," and "subarachnoid hemorrhage" were the main keywords. Only human case-control studies, published from 2005 to 2021, written in English or translated, were screened. In the statistical analysis, we applied the fixed- and random-effect models, according to the level of heterogeneity, to assess the odds ratios (ORs) and 95% confidence intervals (CIs). RevMan 5.0 software was used for the statistics. Results Only 4 studies were eligible, with a total of 2070 patients, 1050 of which were assigned to the study group. Combined results showed a statistically significant association between the risk of IAs and -511CC (OR=0.79, 95% CI [0.65-0.95], p=0.01), and CT (OR=0.69, 95% CI [0.58-0.82], p<0.0001; OR=0.71, 95% CI [0.55-0.93], p=0.01) allele variations, both in the fixed- and random- models. No correlation was identified for the -511TT genotype (p=0.42; p=0.78). All the texts showed a low level of publication bias. Conclusion The present meta-analysis proved a potential role of IL-1β -511CC/CT genotypes in the pathogenesis of IAs. Additional studies are imperative to explain the underlying neuroimmune mechanisms, also allowing tailoring the potential inflammatory-target therapies for IAs.

The cranio-orbito-zygomatic (COZ) approach consists of an extension of the pterional approach characterized by the removal of the superolateral part of the orbital rim and zygoma. This key step tremendously increases the angular exposure to some deep targets and overall surgical freedom to the lesion. In this article we review the technical variations of the COZ approach, mainly focusing on the differential quantitative effects coming from the orbital osteotomy compared to the zygomatic one.

Background: The cranio-orbito-zygomatic (COZ) approach is a workhorse of skull base surgery, and each of its steps has a precise effect on target exposure and surgical freedom. The present study overviews the key techniques for execution and tailoring of the COZ approach, focusing on the quantitative effects resulting from removal of the orbitozygomatic (OZ) bar, orbital rim, and zygomatic arch., Methods: A PRISMA-based literature review was performed on the PubMed/Medline and Web of Science databases using the main keywords associated with the COZ approach. Articles in English without temporal restriction were included. Eligibility was limited to neurosurgical relevance., Results: A total of 78 articles were selected. The range of variants of the COZ approach involves a one-piece, two-piece, and three-piece technique, with a decreasing level of complexity and risk of complications. The two-piece technique includes an OZ and orbitopterional variant. Superolateral orbitotomy expands the subfrontal and transsylvian corridors, increasing surgical freedom to the basal forebrain, hypothalamic region, interpeduncular fossa, and basilar apex. Zygomatic osteotomy shortens the working distance of the pretemporal and subtemporal routes., Conclusion: Subtraction of the OZ bar causes a tremendous increase in angular exposure of the subfrontal, transsylvian, pretemporal, and subtemporal perspectives avoiding brain retraction, allowing for multiangled trajectories, and shortening the working distance. The COZ approach can be tailored based on the location of the lesion, thus optimizing the target exposure and surgical freedom and decreasing the risk of complications.