Brain tumor surgery guided by navigated transcranial magnetic stimulation mapping for arithmetic calculation.

OBJECTIVE: The onco-functional balance represents the primary goal in neuro-oncology. The increasing use of navigated transcranial magnetic stimulation (nTMS) allows the noninvasive characterization of cortical functional anatomy, and its reliability for motor and language mapping has previously been validated. Calculation and arithmetic processing has not been studied with nTMS so far. In this study, the authors present their preliminary data concerning nTMS calculation. METHODS: The authors designed a monocentric prospective study, adopting an internal protocol to use nTMS for preoperative planning, including arithmetic processing. When awake surgery was possible, according to the patients' conditions, nTMS points were used to guide direct cortical stimulation (DCS), i.e., the gold standard for cortical mapping. Navigated TMS-based tractography was used for surgical planning. Statistical analyses on the nTMS and DCS points were performed. RESULTS: From February 2021 to October 2023, 61 procedures for nTMS calculation mapping were performed. The clinical evaluation, including pre- and postoperative evaluations (3 months after surgery), demonstrated a good clinical outcome with preservation of arithmetic function and recovery (92.8% of patients). Between the awake and asleep surgery groups, the postoperative clinical results were comparable at the 3-month follow-up, with > 90% of the patients achieving improved calculation function. The surgical strategy adopted was aimed at sparing nTMS positive points in asleep procedures, whereas nTMS and DCS positive points were not removed in awake procedures. Overall, 62% of the positive points for calculation functions were exposed by craniotomy and 85% were spared during surgery. None of the patients developed nTMS-related seizures. Diffusion tensor imaging fiber tracking based on nTMS positive points for calculation was used. The white matter fiber tracts involved in calculation functions were the arcuate fasciculus (56%) and frontal aslant tract (22%). When nTMS and DCS points were compared in awake surgery (n = 10 patients), a sensitivity of 31.71%, specificity of 85.76%, positive predictive value of 22.41%, negative predictive value of 90.64%, and accuracy of approximately 69% were achieved. CONCLUSIONS: Based on the authors' preliminary data, nTMS can be an advantageous tool to study cognitive functions, aimed at minimizing neurological impairment. The postoperative clinical outcome for patients who underwent operation with nTMS was very good. Considering these results, nTMS has proved to be a feasible method to map cognitive areas including those for calculation functions. Further analyses are needed to validate these data. Finally, other cognitive functions (e.g., visuospatial) may be explored with nTMS.

Intraoperative seizures during neuro-oncological supratentorial surgery: the role of prophylaxis with levetiracetam and intraoperative monitoring in a consecutive series of 353 patients.

BACKGROUND: The aim of this paper was to understand the role of prophylaxis with levetiracetam at skin incision in preventing convulsive intraoperative seizures (IOS) during neurosurgical procedures with and without intraoperative neuromonitoring (IONM). METHODS: Authors retrospectively reviewed the Institutional database for cases of supratentorial brain tumors undergoing surgical resection performed from January 2021 to October 2022. Patients were operated on both under general anesthesia and awake, using motor-evoked potentials (MEP) and direct cortical stimulation for cortical mapping. 1000 mg ev of Levetiracetam before skin incision in case of a history of seizures was administrated. We excluded all infratentorial cases. RESULTS: Three hundred fisty three consecutive cases were retrieved. IOS occurred in 22 patients (6.2%). Prophylaxis with Levetiracetam was administered in 149 patients, and IOS occurred in 16 cases (10.7%) in this group of patients. The IOS rate in the case of no Levetiracetam prophylaxis administration (3.5%) was significantly lower (P<0.001, OR=3.38 [1.35-8.45], RR=3.12 [1.32-7.41]). The Penfield technique stimulation evoked seven of all 22 IOS reported (31.8%) (P=0.006, RR 5.4 [1.44 -20.58], OR 21 [2.3-183.9]), and the train-of-five technique stimulation caused two of all registered IOS (8.7%) (P=0.2, RR 2.3 [0.99-5.67], OR 6.5 [0.55-76.17]). Transcranial MEPs evoked no IOS. CONCLUSIONS: Under levetiracetam prophylaxis, the IOS rate was not significantly lower than in the group of patients without Levetiracetam prophylaxis, regardless of the histology of the tumor and IONM. Neither the transcranial stimulation (MEP) nor train-of-five technique stimulation increases the risk of convulsive IOS, as Penfield technique stimulation does.

Re-irradiation for recurrent intracranial meningiomas: Analysis of clinical outcomes and prognostic factors.

PURPOSE: Re-irradiation (re-RT) for recurrent intracranial meningiomas is hindered by the limited radiation tolerance of surrounding tissue and the risk of side effects. This study aimed at assessing outcomes, toxicities and prognostic factors in a cohort of patients with recurrent meningiomas re-treated with different RT modalities. MATERIALS AND METHODS: A multi-institutional database from 8 Italian centers including intracranial recurrent meningioma (RM) patients who underwent re-RT with different modalities (SRS, SRT, PT, EBRT) was collected. Biologically Equivalent Dose in 2 Gy-fractions (EQD2) and Biological Effective Dose (BED) for normal tissue and tumor were estimated for each RT course (α/ß = 2 for brain tissue and α/ß = 4 for meningioma). Primary outcome was second progression-free survival (s-PFS). Secondary outcomes were overall survival (OS) and treatment-related toxicity. Kaplan-Meier curves and Cox regression models were used for analysis. RESULTS: Between 2003 and 2021 181 patients (pts) were included. Median age at re-irradiation was 62 (range 20-89) and median Karnofsky Performance Status (KPS) was 90 (range 60-100). 78 pts were identified with WHO grade 1 disease, 65 pts had grade 2 disease and 10 pts had grade 3 disease. 28 pts who had no histologic sampling were grouped with grade 1 patients for further analysis. Seventy-five (41.4 %) patients received SRS, 63 (34.8 %) patients SRT, 31 (17.1 %) PT and 12 (6.7 %) EBRT. With a median follow-up of 4.6 years (interquartile range 1.7-6.8), 3-year s-PFS was 51.6 % and 3-year OS 72.5 %. At univariate analysis, SRT (HR 0.32, 95 % CI 0.19-0.55, p < 0.001), longer interval between the two courses of irradiation (HR 0.37, 95 % CI 0.21-0.67, p = 0.001), and higher tumor BED (HR 0.45 95 % CI 0.27-0.76, p = 0.003) were associated with longer s-PFS; in contrast, Ki67 > 5 % (HR 2.81, 95 % CI 1.48-5.34, p = 0.002) and WHO grade > 2 (HR 3.08, 95 % CI 1.80-5.28, p < 0.001) were negatively correlated with s-PFS. At multivariate analysis, SRT, time to re-RT and tumor BED maintained their statistically significant prognostic impact on s-PFS (HR 0.36, 95 % CI 0.21-0.64, p < 0.001; HR 0.38, 95 % CI 0.20-0.72, p = 0.003 and HR 0.31 95 % CI 0.13-0.76, p = 0.01, respectively). Acute and late adverse events (AEs) were reported in 38 (20.9 %) and 29 (16 %) patients. Larger tumor GTV (≥10 cc) was significantly associated with acute and late toxicity (p < 0.001 and p = 0.009, respectively). CONCLUSIONS: In patients with recurrent meningiomas, reirradiation is a feasible treatment option associated with acceptable toxicity profile. Prognostic factors in the decision-making process have been identified and should be incorporated in daily practice.

Neurocognitive Assessment of Mathematics-Related Capacities in Neurosurgical Patients.

A precise neuropsychological assessment is of the utmost importance for neurosurgical patients undergoing the surgical excision of cerebral lesions. The assessment of mathematical abilities is usually limited to arithmetical operations while other fundamental visuo-spatial aspects closely linked to mathematics proficiency, such as the perception of numerical quantities and geometrical reasoning, are completely neglected. We evaluated these abilities with two objective and reproducible psychophysical tests, measuring numerosity perception and non-symbolic geometry, respectively. We tested sixteen neuro-oncological patients before the operation and six after the operation with classical neuropsychological tests and with two psychophysical tests. The scores of the classical neuropsychological tests were very heterogeneous, possibly due to the distinct location and histology of the tumors that might have spared (or not) brain areas subserving these abilities or allowed for plastic reorganization. Performance in the two non-symbolic tests reflected, on average, the presumed functional role of the lesioned areas, with participants with parietal and frontal lesions performing worse on these tests than patients with occipital and temporal lesions. Single-case analyses not only revealed some interesting exceptions to the group-level results (e.g., patients with parietal lesions performing well in the numerosity test), but also indicated that performance in the two tests was independent of non-verbal reasoning and visuo-spatial working memory. Our results highlight the importance of assessing non-symbolic numerical and geometrical abilities to complement typical neuropsychological batteries. However, they also suggest an avoidance of reliance on an excessively rigid localizationist approach when evaluating the neuropsychological profile of oncological patients.

Can exoscope improve brain AVMs surgery?

The advantages of the surgical view provided by the exoscope have been described before, although reports of its application to brain arteriovenous malformation (AVM) surgery are lacking. The ampler field of view and magnification up to ×24 allow for enhanced visualization during microsurgical procedures. Furthermore, the live visualization provided by indocyanine green video angiography (ICG-VA) helps emphasize the hemodynamics of AVMs, even allowing the detection of possible residual vein arterialization as an indirect expression of nidal remnants. With this illustrative video showing the resection of a hemorrhagic right frontoinsular Spetzler-Martin grade III AVM, the authors describe the technical implications of exoscope brain AVM surgery using the Olympus ORBEYE 4K-3D, with a final focus on ICG-VA as an asset. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23114.

Sodium fluorescein uptake by the tumor microenvironment in human gliomas and brain metastases.

OBJECTIVE: Intravenous sodium fluorescein (SF) is increasingly used during surgery of gliomas and brain metastases to improve tumor resection. Currently, SF is believed to permeate the brain regions where the blood-brain barrier (BBB) is damaged and to accumulate in the extracellular space but not in tumor or healthy cells, making it possible to demarcate tumor margins to guide resection. By evaluating the immune contexture of a number of freshly resected gliomas and brain metastases from patients undergoing SF-guided surgery, the authors recurrently observed fluorescence-positive cells. Therefore, the aim of this study was to determine if SF accumulates inside the cells of the tumor microenvironment (TME), and if so, in which type of cells, and whether incorporation can also be observed in the leukocytes of peripheral blood. METHODS: Freshly resected tumor specimens were dissociated to single cells and analyzed by multiparametric flow cytometry. Peripheral blood leukocytes, macrophages, and a glioma cell line were treated with SF in vitro, and their cell uptake was assessed by multiparametric and imaging flow cytometry and by confocal microscopy. RESULTS: The ex vivo and in vitro analyses revealed that SF accumulates intracellularly in leukocytes as well as in tumor cells, but with a high variability of incorporation in the different cell subsets analyzed. Myeloid cells showed the highest level of fluorescence. In vitro uptake experiments showed that SF accumulation increases over time. The imaging analyses confirmed the internalization of the compound inside the cells. CONCLUSIONS: SF is not just a marker of BBB damage, but its intracellular detection suggests that it selectively accumulates intracellularly. Future efforts should target the mechanisms of its differential uptake by the different TME cell types in depth.

Heads-Up Micronavigation Reliability of Preoperative Transcranial Magnetic Stimulation Maps for the Motor Function: Comparison With Direct Cortical Stimulation.

BACKGROUND AND OBJECTIVES: We aimed to assess the reliability of preoperative navigated transcranial magnetic stimulation (nTMS) maps for motor function as visualized intraoperatively with augmented reality heads-up display and to assess its accuracy via direct point-by-point comparison with the gold-standard direct cortical stimulation (DCS). METHODS: From January 2022 to January 2023, candidates for surgical removal of lesions involving the motor pathways underwent preoperative nTMS assessment to obtain cortical maps of motor function. Intraoperatively and before tumor removal, nTMS maps were superimposed on the cortical surface, and DCS was performed on positive points with increasing current intensity until obtaining a positive response at 16 mA. The outcome of each stimulation was recorded to obtain discrimination metrics. RESULTS: Twelve patients were enrolled (5 females [42%] vs 7 males [58%], mean age 62.9 ± 12.8 years), for a total of 304 investigated points. Agreement between nTMS and DCS was moderate (κ = 0.43, P < .005), with 0.66 (0.53-0.78) sensitivity, 0.87 (0.82-0.90) specificity, 0.50 (0.39-0.62) positive predictive values, 0.93 (0.89-0.95) negative predictive value, and 0.83 (0.79-0.87) accuracy. A loss of accuracy was observed with higher DCS current intensities. CONCLUSION: We performed a point-by-point validation of preoperative nTMS maps for motor function using augmented reality visualization. The high negative predictive value and low positive predictive values highlight nTMS reliability to visualize safe cortical zones but not to identify critical functional areas, confirming previous findings of nTMS maps for the language function and suggesting the need for combined use of nTMS maps and DCS for optimal maximal safe resection.

The immune cell landscape of glioblastoma patients highlights a myeloid-enriched and immune suppressed microenvironment compared to metastatic brain tumors.

Introduction: Brain metastases (BrM), which commonly arise in patients with melanoma, breast cancer and lung cancer, are associated with a poor clinical prognosis. In this context, the tumor microenvironment (TME) plays an important role since it either promotes or inhibits tumor progression. Our previous studies have characterized the immunosuppressive microenvironment of glioblastoma (GBM). The aim of this study is to compare the immune profiles of BrM and GBM in order to identify potential differences that may be exploited in their differential treatment. Methods: Tumor and/or blood samples were taken from 20 BrM patients and 19 GBM patients. Multi-parametric flow cytometry was used to evaluate myeloid and lymphoid cells, as well as the expression of immune checkpoints in the TME and blood. In selected cases, the immunosuppressive ability of sorted myeloid cells was tested, and the ex vivo proliferation of myeloid, lymphoid and tumor cell populations was analyzed. Results: High frequencies of myeloid cells dominated both the BrM and GBM landscapes, but a higher presence of tumor-associated macrophages was observed in GBM, while BrM were characterized by a significant presence of tumor-infiltrating lymphocytes. Exhaustion markers were highly expressed in all T cells from both primary and metastatic brain tumors. Ex vivo analysis of the cell cycle of a single sample of a BrM and of a GBM revealed subsets of proliferating tumor cells and blood-derived macrophages, but quiescent resident microglial cells and few proliferating lymphocytes. Macrophages sorted from a single lung BrM exhibited a strong immunosuppressive activity, as previously shown for primary GBM. Finally, a significant expansion of some myeloid cell subsets was observed in the blood of both GBM and BrM patients. Discussion: Our results define the main characteristics of the immune profile of BrM and GBM, which are distinguished by different levels of immunosuppressive myeloid cells and lymphocytes devoid of effector function. Understanding the role of the different cells in establishing the metastatic setting is critical for improving the therapeutic efficacy of new targeted immunotherapy strategies.

Is the Patient State Index a reliable parameter as guide to anaesthesiology in cranial neurosurgery? A first intraoperative study and a literature review.

BACKGROUND: Patient State Index (PSI) and Suppression Ratio (SR) are two indices calculated by quantitative analysis of EEG used to estimate the depth of anaesthesia but their validation in neurosurgery must be done. Our aim was to investigate the congruity PSI and SR with raw EEG monitoring in neurosurgery. METHODS: We included 34 patients undergoing elective cranial neurosurgery. Each patient was monitored by a SedLine device (PSI and SR) and by raw EEG. To appraise the agreement between PSI, SR and EEG Suppr%, Bland-Altman analysis was used. We also correlated the PSI and SR recorded at different times during surgery to the degree of suppression of the raw EEG data by Spearman's rank correlation coefficient. For a comparison with previous data we made an international literature review according to PRISMA protocol. RESULTS: At all recording times, we found that there is a strong agreement between PSI and raw EEG. We also found a significant correlation for both PSI and SR with the EEG suppression percentage (p < 0.05), but with a broad dispersion of the individual values within the confidence interval. CONCLUSION: The Masimo SedLine processed EEG monitoring system can be used as a guide in the anaesthetic management of patients during elective cranial neurosurgery, but the anaesthesiologist must be aware that previous correlations between PSI and SR with the suppression percentage may not always be valid in all individual patients. The use of an extended visual raw EEG evaluated by an expert electroencephalographer might help to provide better guidance.

A common low dimensional structure of cognitive impairment in stroke and brain tumors.

INTRODUCTION: Neuropsychological studies infer brain-behavior relationships from focal lesions like stroke and tumors. However, these pathologies impair brain function through different mechanisms even when they occur at the same brain's location. The aim of this study was to compare the profile of cognitive impairment in patients with brain tumors vs. stroke and examine the correlation with lesion location in each pathology. METHODS: Patients with first time stroke (n = 77) or newly diagnosed brain tumors (n = 76) were assessed with a neuropsychological battery. Their lesions were mapped with MRI scans. Test scores were analyzed using principal component analysis (PCA) to measure their correlation, and logistic regression to examine differences between pathologies. Next, with ridge regression we examined whether lesion features (location, volume) were associated with behavioral performance. RESULTS: The PCA showed a similar cognitive impairment profile in tumors and strokes with three principal components (PCs) accounting for about half of the individual variance. PC1 loaded on language, verbal memory, and executive/working memory; PC2 loaded on general performance, visuo-spatial attention and memory, and executive functions; and, PC3 loaded on calculation, reading and visuo-spatial attention. The average lesion distribution was different, and lesion location was correlated with cognitive deficits only in stroke. Logistic regression found language and calculation more affected in stroke, and verbal memory and verbal fluency more affected in tumors. CONCLUSIONS: A similar low dimensional set of behavioral impairments was found both in stroke and brain tumors, even though each pathology caused some specific deficits in different domains. The lesion distribution was different for stroke and tumors and correlated with behavioral impairment only in stroke.

Temporal lobe tumors modify local venous drainage.

OBJECTIVE: Superficial Middle Cerebral Vein (SMCV) is an anastomotic vein frequently exposed during surgery. Changes in the pattern of cerebral venous outflow can occur in many pathological settings. We explored the hypothesis that the growth of an intracranial tumor could determine alterations in the venous outflow. We analyzed SMCV anatomical variants in patients undergoing surgery for intracranial tumors; we furthermore focused on association with histology. METHODS: We retrospectively collected data of 120 patients undergoing surgery, 60 presenting intracranial tumor and 60 presenting cerebral aneurysms (control group). Tumor series was divided into "Low Growth-Rate tumors" (WHO grade I and II) and "High Growth-Rate tumors" (WHO grade III and IV). Anatomical variants of SMCV were analyzed on intraoperative videos and then classified as Type 1 (normotrophic), 2 A (hypotrophic) and Type 2B (absent/atrophic). We furthermore defined as Type 2 any alteration of the SMCV (2 A+2B) encountered. Relationships among SMCV types and both populations were analyzed using the chi-squared test; values of p < 0.05 were considered statistically significant. RESULTS: We found a positive correlation between the presence of a primary brain tumor and Type 2B SMCV (PC.004, p < 0.05) and Type 2 SMCV (PC.000, p < 0.05). Specifically, we found a strong correlation between the absence of SMCV (Type 2B) and both tumors subgroups. Thus, the growth of a primary brain tumor seems to affect the cerebral local outflow. CONCLUSIONS: Primary brain tumors seem to alter local venous network of SMCV. Clinical and oncological implications remain subject of further investigation.

Intraoperative Mapping of the Sensory Root of the Trigeminal Nerve in Patients with Pontocerebellar Angle Pathology.

OBJECTIVE: The aim of the present study was to determine the position of the 3 sensory branches of the trigeminal nerve in the preganglionic tract using intraoperative neurophysiological mapping. METHODS: We included consecutive adult patients who underwent neurosurgical treatment of cerebellopontine angle lesions. The trigeminal nerve was antidromically stimulated at 3 sites along its circumference with different stimulus intensities at a distance of ≤1 cm from the brainstem. The sensory nerve action potentials (SNAPs) were recorded from each main trigeminal branch (V1 [ophthalmic branch], V2 [maxillary branch], and V3 [mandibular branch]). RESULTS: We analyzed 13 patients. The stimulation points at which we obtained the greatest number of congruous and exclusive SNAPs (SNAPs only on the stimulated branch) was the stimulation point for V3 (20.7%). The stimulation intensity at which we obtained the highest number of congruent and exclusive SNAPs with the stimulated branch was 0.5 mA. CONCLUSIONS: Using our recording conditions, trigeminal stimulation is a reliable technique for mapping the V3 and V1 branches using an intensity not exceeding 0.5. However, reliable identification of the fibers of V2 is more difficult. Stimulation of the trigeminal nerve can be a reliable technique to identify the V3 and V1 branches if rhizotomy of these branches is necessary.

Collagen VI sustains cell stemness and chemotherapy resistance in glioblastoma.

Microenvironmental factors are known fundamental regulators of the phenotype and aggressiveness of glioblastoma (GBM), the most lethal brain tumor, characterized by fast progression and marked resistance to treatments. In this context, the extracellular matrix (ECM) is known to heavily influence the behavior of cancer cells from several origins, contributing to stem cell niches, influencing tumor invasiveness and response to chemotherapy, mediating survival signaling cascades, and modulating inflammatory cell recruitment. Here, we show that collagen VI (COL6), an ECM protein widely expressed in both normal and pathological tissues, has a distinctive distribution within the GBM mass, strongly correlated with the most aggressive and phenotypically immature cells. Our data demonstrate that COL6 sustains the stem-like properties of GBM cells and supports the maintenance of an aggressive transcriptional program promoting cancer cell proliferation and survival. In particular, we identified a specific subset of COL6-transcriptionally co-regulated genes, required for the response of cells to replicative stress and DNA damage, supporting the concept that COL6 is an essential stimulus for the activation of GBM cell response and resistance to chemotherapy, through the ATM/ATR axis. Altogether, these findings indicate that COL6 plays a pivotal role in GBM tumor biology, exerting a pleiotropic action across different GBM hallmarks, including phenotypic identity and gene transcription, as well as response to treatments, thus providing valuable information for the understanding of the complex microenvironmental cues underlying GBM malignancy.

Conventional and Advanced Magnetic Resonance Imaging Assessment of Non-Enhancing Peritumoral Area in Brain Tumor.

The non-enhancing peritumoral area (NEPA) is defined as the hyperintense region in T2-weighted and fluid-attenuated inversion recovery (FLAIR) images surrounding a brain tumor. The NEPA corresponds to different pathological processes, including vasogenic edema and infiltrative edema. The analysis of the NEPA with conventional and advanced magnetic resonance imaging (MRI) was proposed in the differential diagnosis of solid brain tumors, showing higher accuracy than MRI evaluation of the enhancing part of the tumor. In particular, MRI assessment of the NEPA was demonstrated to be a promising tool for distinguishing high-grade gliomas from primary lymphoma and brain metastases. Additionally, the MRI characteristics of the NEPA were found to correlate with prognosis and treatment response. The purpose of this narrative review was to describe MRI features of the NEPA obtained with conventional and advanced MRI techniques to better understand their potential in identifying the different characteristics of high-grade gliomas, primary lymphoma and brain metastases and in predicting clinical outcome and response to surgery and chemo-irradiation. Diffusion and perfusion techniques, such as diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), dynamic susceptibility contrast-enhanced (DSC) perfusion imaging, dynamic contrast-enhanced (DCE) perfusion imaging, arterial spin labeling (ASL), spectroscopy and amide proton transfer (APT), were the advanced MRI procedures we reviewed.

Association between thyroid function and regorafenib efficacy in patients with relapsed wild-type IDH glioblastoma: a large multicenter study.

PURPOSE: Regorafenib demonstrated encouraging results in recurrent glioblastoma patients. Some studies showed that changes in circulating thyroid hormones (fT3, fT4, fT3/fT4 ratio) can be considered as prognostic factors in patients with various types of tumors. We designed this study to investigate the relationship between baseline thyroid variables and outcome in IDH-wild type GBM patients who were treated with regorafenib. METHODS: This multicenter retrospective study included recurrent IDH-wild-type glioblastoma patients treated with regorafenib. Only patients with baseline thyroid function values (TSH, fT3, fT4, fT3/fT4 ratio) available were evaluated. RANO criteria were used to analyze neuroradiological response. Survival curves were estimated using the Kaplan-Meier method. The relationships between baseline thyroid variables (TSH, fT3, fT4, fT3/fT4) and survival (PFS, OS) were investigated with Cox regression models. RESULTS: From November 2015 to April 2022, 134 recurrent IDH-wildtype GBM patients were treated with regorafenib and 128 of these had information on baseline thyroid function value. Median follow-up was 8 months (IQR 4.7-14.0). Objective Response Rate was 9% and Disease Control Rate was 40.9%. Median PFS was 2.7 months (95%CI 2.2-3.6) and median OS was 10.0 months (95%CI 7.0-13.0). Lower baseline TSH value in the blood was correlated with a higher rate of disease progression to regorafenib (p = 0.04). Multivariable analyses suggested a non-linear relationship between PFS (p = 0.01) and OS (p = 0.03) with baseline fT3/fT4 ratio. CONCLUSION: In recurrent wild-type IDH glioblastoma patients, baseline fT3/fT4 ratio showed a non-linear relationship with survival, with different impacts across the spectrum of fT3/fT4 ratio. Moreover, baseline TSH may be a predictor of regorafenib activity.

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review.

PURPOSE: The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal. METHODS: A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients. RESULTS: A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B). CONCLUSIONS: A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity.

Microscope neuronavigation-guided microsurgical fenestration of quadrigeminal cistern arachnoid cysts: how I do it.

BACKGROUND: Management options for treatment of quadrigeminal arachnoid cysts (QAC) include microsurgical/endoscopic fenestration or shunt. There is an open debate about which method is the best. Microsurgical fenestration is well suited for treatment of QAC with predominant infratentorial component and without hydrocephalus making endoscopic procedures more challenging. METHOD: We describe the microsurgical technique and related anatomy to fenestrate infratentorial QAC through supracerebellar infratentorial approach. We also discuss our experiences with this approach, some of the drawbacks and nuances. CONCLUSION: Navigation-guided microsurgical fenestration of infratentorial QAC is the authors' surgical approach of choice for treating these rare challenging lesions when not associated with hydrocephalus.

A Diffusion Tensor Imaging-Based Prognostic Classification for Surgery of Intrinsic Lesions Involving the Motor Pathways.

BACKGROUND: The critical role of different adjuncts in improving the neurological outcome in intrinsic brain lesions affecting eloquent areas is demonstrated by their more diffuse utilization. Neurosurgeons often rely on preoperative and intraoperative diffusion tensor imaging tractography to improve the operative strategy and prognosis. We aimed to identify and validate a diffusion tensor imaging-based classification considering the relationship between the brain lesion and the corticospinal tract to predict a >50% reduction of motor evoked potentials (MEPs) during surgical excision of lesions involving the motor pathways. METHODS: We included patients consecutively enrolled at our institution between April 2020 and September 2022 with 3 patterns of increasing complexity according to the relationship between the lesion and the corticospinal tract as identified on preoperative diffusion tensor imaging. Outcome measures were >50% reduction in intraoperative MEPs and neurological outcome defined as unchanged, improved, or worsened. RESULTS: The study included 83 patients. A statistically significant linear trend between higher rates of reduction of MEPs and higher classification grades was observed (P = 0.001), with sensitivity 0.60, specificity 0.88, accuracy 0.83, and area under the curve 0.75. Higher grades were associated with worse neurological outcomes (P = 0.02). CONCLUSIONS: The classification proved reliable in anticipating reduction in intraoperative MEPs and in predicting neurological outcome. Using this classification in patients undergoing surgery for lesions involving the motor pathways could help in counseling the patient, surgical planning, enhancing teamwork of operating room personnel, and improving the patient's prognosis.