Barriers and facilitators in the implementation of a telemedicine-based outpatient brain tumor surgery program.

OBJECTIVE: Despite growing evidence on the benefits of outpatient oncological neurosurgery (OON), it is only performed in a few specialized centers and there are no previous descriptions of established OON programs in Europe. Moreover, increasing application of telemedicine strategies, especially after the start of the coronavirus disease 2019 (COVID-19) pandemic, is drastically changing neurosurgical management, particularly in the case of vulnerable populations such as neuro-oncological patients. In this context, the authors implemented an OON program in their hospital with telematic follow-up. Herein, they describe the protocol and qualitatively analyze the barriers and facilitators of the development process. METHODS: An OON program was developed through the following steps: assessment of hospital needs, specific OON training, multidisciplinary team organization, and OON protocol design. In addition, the implementation phase included training sessions, a pilot study, and continuous improvement sessions. Finally, barriers and facilitators of the protocol's implementation were identified from the feedback of all participants. RESULTS: An OON protocol was successfully designed and implemented for resection or biopsy of supratentorial lesions up to 3 cm in diameter. The protocol included the patient's admission to the day surgery unit, noninvasive anesthetic monitoring, same-day discharge, and admission to the hospital-at-home (HaH) unit for telematic and on-site postoperative care. After a pilot study including 10 procedures in 9 patients, the main barriers identified were healthcare provider resistance to change, lack of experience in outpatient neurosurgery, patient reluctance, and limitations in the recruitment of patients. Key facilitators of the process were the patient education program, the multidisciplinary team approach, and the HaH-based telematic postoperative care. CONCLUSIONS: Initiating an OON program with telematic follow-up in a European clinical setting is feasible. Nevertheless, it poses several barriers that can be overcome by identifying and maximizing key facilitators of the process. Among them, patient education, a multidisciplinary team approach, and HaH-based postoperative care were crucial to the success of the program. Future studies should investigate the cost-effectiveness of telemedicine to assess potential cost savings, from reduced travel and wait times, and the impact on patient satisfaction.

Anterior transtemporal endoscopic selective amygdalohippocampectomy: a virtual and cadaveric feasibility study.

PURPOSE: Selective amygdalohippocampectomy (SelAH) is one of the most common surgical treatments for mesial temporal sclerosis. Microsurgical approaches are associated with the risk of cognitive and visual deficits due to damage to the cortex and white matter (WM) pathways. Our objective is to test the feasibility of an endoscopic approach through the anterior middle temporal gyrus (aMTG) to perform a SelAH. METHODS: Virtual simulation with MRI scans of ten patients (20 hemispheres) was used to identify the endoscopic trajectory through the aMTG. A cadaveric study was performed on 22 specimens using a temporal craniotomy. The anterior part of the temporal horn was accessed using a tubular retractor through the aMTG after performing a 1.5 cm corticectomy at 1.5 cm posterior to the temporal pole. Then, an endoscope was introduced. SeIAH was performed in each specimen. The specimens underwent neuronavigation-assisted endoscopic SeIAH to confirm our surgical trajectory. WM dissection using Klingler's technique was performed on five specimens to assess WM integrity. RESULTS: This approach allowed the identification of collateral eminence, lateral ventricular sulcus, choroid plexus, inferior choroidal point, amygdala, hippocampus, and fimbria. SelAH was successfully performed on all specimens, and CT neuronavigation confirmed the planned trajectory. WM dissection confirmed the integrity of language pathways and optic radiations. CONCLUSIONS: Endoscopic SelAH through the aMTG can be successfully performed with a corticectomy of 15 mm, presenting a reduced risk of vascular injury and damage to WM pathways. This could potentially help to reduce cognitive and visual deficits associated with SelAH.

The STARMEN trial indicates that alternating treatment with corticosteroids and cyclophosphamide is superior to sequential treatment with tacrolimus and rituximab in primary membranous nephropathy.

A cyclical corticosteroid-cyclophosphamide regimen is recommended for patients with primary membranous nephropathy at high risk of progression. We hypothesized that sequential therapy with tacrolimus and rituximab is superior to cyclical alternating treatment with corticosteroids and cyclophosphamide in inducing persistent remission in these patients. This was tested in a randomized, open-label controlled trial of 86 patients with primary membranous nephropathy and persistent nephrotic syndrome after six-months observation and assigned 43 each to receive six-month cyclical treatment with corticosteroid and cyclophosphamide or sequential treatment with tacrolimus (full-dose for six months and tapering for another three months) and rituximab (one gram at month six). The primary outcome was complete or partial remission of nephrotic syndrome at 24 months. This composite outcome occurred in 36 patients (83.7%) in the corticosteroid-cyclophosphamide group and in 25 patients (58.1%) in the tacrolimus-rituximab group (relative risk 1.44; 95% confidence interval 1.08 to 1.92). Complete remission at 24 months occurred in 26 patients (60%) in the corticosteroid-cyclophosphamide group and in 11 patients (26%) in the tacrolimus-rituximab group (2.36; 1.34 to 4.16). Anti-PLA2R titers showed a significant decrease in both groups but the proportion of anti-PLA2R-positive patients who achieved immunological response (depletion of anti-PLA2R antibodies) was significantly higher at three and six months in the corticosteroid-cyclophosphamide group (77% and 92%, respectively), as compared to the tacrolimus-rituximab group (45% and 70%, respectively). Relapses occurred in one patient in the corticosteroid-cyclophosphamide group, and three patients in the tacrolimus-rituximab group. Serious adverse events were similar in both groups. Thus, treatment with corticosteroid-cyclophosphamide induced remission in a significantly greater number of patients with primary membranous nephropathy than tacrolimus-rituximab.

Heschl's gyrus fiber intersection area: a new insight on the connectivity of the auditory-language hub.

OBJECTIVE: The functional importance of the superior temporal lobe at the level of Heschl's gyrus is well known. However, the organization and function of these cortical areas and the underlying fiber tracts connecting them remain unclear. The goal of this study was to analyze the area formed by the organization of the intersection of Heschl's gyrus-related fiber tracts, which the authors have termed the "Heschl's gyrus fiber intersection area" (HGFIA). METHODS: The subcortical connectivity of Heschl's gyrus tracts was analyzed by white matter fiber dissection and by diffusion tensor imaging tractography. The white matter tracts organized in relation to Heschl's gyrus were isolated in 8 human hemispheres from cadaveric specimens and in 8 MRI studies in 4 healthy volunteers. In addition, these tracts and their functions were described in the surgical cases of left temporal gliomas next to the HGFIA in 6 patients who were awake during surgery and underwent intraoperative electrical stimulation mapping. RESULTS: Five tracts were observed to pass through the HGFIA: the anterior segment of the arcuate fasciculus, the middle longitudinal fasciculus, the acoustic radiation, the inferior fronto-occipital fasciculus, and the optic radiation. In addition, U fibers originating at the level of Heschl's gyrus and heading toward the middle temporal gyrus were identified. CONCLUSIONS: This investigation of the HGFIA, a region where 5 fiber tracts intersect in a relationship with the primary auditory area, provides new insights into the subcortical organization of Wernicke's area. This information is valuable when a temporal surgical approach is planned, in order to assess the surgical risk related to language disturbances.

Morphological MRI-based features provide pretreatment survival prediction in glioblastoma.

OBJECTIVES: We wished to determine whether tumor morphology descriptors obtained from pretreatment magnetic resonance images and clinical variables could predict survival for glioblastoma patients. METHODS: A cohort of 404 glioblastoma patients (311 discoveries and 93 validations) was used in the study. Pretreatment volumetric postcontrast T1-weighted magnetic resonance images were segmented to obtain the relevant morphological measures. Kaplan-Meier, Cox proportional hazards, correlations, and Harrell's concordance indexes (c-indexes) were used for the statistical analysis. RESULTS: A linear prognostic model based on the outstanding variables (age, contrast-enhanced (CE) rim width, and surface regularity) identified a group of patients with significantly better survival (p < 0.001, HR = 2.57) with high accuracy (discovery c-index = 0.74; validation c-index = 0.77). A similar model applied to totally resected patients was also able to predict survival (p < 0.001, HR = 3.43) with high predictive value (discovery c-index = 0.81; validation c-index = 0.92). Biopsied patients with better survival were well identified (p < 0.001, HR = 7.25) by a model including age and CE volume (c-index = 0.87). CONCLUSIONS: Simple linear models based on small sets of meaningful MRI-based pretreatment morphological features and age predicted survival of glioblastoma patients to a high degree of accuracy. The partition of the population using the extent of resection improved the prognostic value of those measures. KEY POINTS: • A combination of two MRI-based morphological features (CE rim width and surface regularity) and patients' age outperformed previous prognosis scores for glioblastoma. • Prognosis models for homogeneous surgical procedure groups led to even more accurate survival prediction based on Kaplan-Meier analysis and concordance indexes.

Correction to: Morphological MRI-based features provide pretreatment survival prediction in glioblastoma.

The original version of this article, published on 15 October 2018, unfortunately contained a mistake. The following correction has therefore been made in the original: The name of Mariano Amo-Salas and the affiliation of Ismael Herruzo were presented incorrectly.

The neural pathway midline crossing theory: a historical analysis of Santiago Rámon y Cajal's contribution on cerebral localization and on contralateral forebrain organization.

Throughout history, many scientists have wondered about the reason for neural pathway decussation in the CNS resulting in contralateral forebrain organization. Hitherto, one of the most accepted theories is the one described by the renowned Spanish physician, Santiago Rámon y Cajal at the end of the 19th century. This Nobel Prize winner, among his many contributions to science, gave us the answer to this question: the key lies in the optic chiasm. Based on the fact that the ocular lenses invert the image formed in the retina, Cajal explained how the decussation of the fibers in the optic chiasm is necessary to obtain a continuous image of the outside in the brain. The crossing of the tactile and motor pathways occurred posteriorly as a compensatory mechanism to allow the cortical integration of the sensory, motor, and visual functions. This theory had a great influence on the scientific community of his time, and maintains its importance today, in which none of the theories formulated to date has managed to entirely refute Cajal's. In addition, the decussation of neural pathways plays a significant role in different diseases, especially in the recovery process after a hemispheric lesion and in several congenital pathologies. The advantages of cerebral lateralization have also recently been published, although the evolutionary connection between fiber decussation and cortical function lateralization remains a mystery to be solved. A better understanding of the molecular and genetic substrates of the midline crossing processes might result in significant clinical advances in brain plasticity and repair.

Tumor Surface Regularity at MR Imaging Predicts Survival and Response to Surgery in Patients with Glioblastoma.

Purpose To evaluate the prognostic and predictive value of surface-derived imaging biomarkers obtained from contrast material-enhanced volumetric T1-weighted pretreatment magnetic resonance (MR) imaging sequences in patients with glioblastoma multiforme. Materials and Methods A discovery cohort from five local institutions (165 patients; mean age, 62 years ± 12 [standard deviation]; 43% women and 57% men) and an independent validation cohort (51 patients; mean age, 60 years ± 12; 39% women and 61% men) from The Cancer Imaging Archive with volumetric T1-weighted pretreatment contrast-enhanced MR imaging sequences were included in the study. Clinical variables such as age, treatment, and survival were collected. After tumor segmentation and image processing, tumor surface regularity, measuring how much the tumor surface deviates from a sphere of the same volume, was obtained. Kaplan-Meier, Cox proportional hazards, correlations, and concordance indexes were used to compare variables and patient subgroups. Results Surface regularity was a powerful predictor of survival in the discovery (P = .005, hazard ratio [HR] = 1.61) and validation groups (P = .05, HR = 1.84). Multivariate analysis selected age and surface regularity as significant variables in a combined prognostic model (P < .001, HR = 3.05). The model achieved concordance indexes of 0.76 and 0.74 for the discovery and validation cohorts, respectively. Tumor surface regularity was a predictor of survival for patients who underwent complete resection (P = .01, HR = 1.90). Tumors with irregular surfaces did not benefit from total over subtotal resections (P = .57, HR = 1.17), but those with regular surfaces did (P = .004, HR = 2.07). Conclusion The surface regularity obtained from high-resolution contrast-enhanced pretreatment volumetric T1-weighted MR images is a predictor of survival in patients with glioblastoma. It may help in classifying patients for surgery.

Mapping visuospatial and self-motion perception functions in the left parietal lobe.

Parietal lobe functions include somesthesia, language, calculation, self-motion perception, and visuospatial awareness. In this video, the authors show the intraoperative mapping of a left parietal lobe for a low-grade glioma resection. Standard sensory and language mapping were performed. Interestingly, by using the "Line Bisection" task, subcortical stimulation of the gyrus angularis was repeatedly associated with ipsilateral spatial neglect, often described in the right parietal lobe. In a similar way, subcortical stimulation in a more posterior point elicited episodes of vertigo, probably due to stimulation of the superior longitudinal fasciculus. Both findings were useful to define the functional limit of the resection. The video can be found here: https://youtu.be/qgGDRW_6u0A .

Glioblastoma: does the pre-treatment geometry matter? A postcontrast T1 MRI-based study.

BACKGROUND: The potential of a tumour's volumetric measures obtained from pretreatment MRI sequences of glioblastoma (GBM) patients as predictors of clinical outcome has been controversial. Mathematical models of GBM growth have suggested a relation between a tumour's geometry and its aggressiveness. METHODS: A multicenter retrospective clinical study was designed to study volumetric and geometrical measures on pretreatment postcontrast T1 MRIs of 117 GBM patients. Clinical variables were collected, tumours segmented, and measures computed including: contrast enhancing (CE), necrotic, and total volumes; maximal tumour diameter; equivalent spherical CE width and several geometric measures of the CE "rim". The significance of the measures was studied using proportional hazards analysis and Kaplan-Meier curves. RESULTS: Kaplan-Meier and univariate Cox survival analysis showed that total volume [p = 0.034, Hazard ratio (HR) = 1.574], CE volume (p = 0.017, HR = 1.659), spherical rim width (p = 0.007, HR = 1.749), and geometric heterogeneity (p = 0.015, HR = 1.646) were significant parameters in terms of overall survival (OS). Multivariable Cox analysis for OS provided the later two parameters as age-adjusted predictors of OS (p = 0.043, HR = 1.536 and p = 0.032, HR = 1.570, respectively). CONCLUSION: Patients with tumours having small geometric heterogeneity and/or spherical rim widths had significantly better prognosis. These novel imaging biomarkers have a strong individual and combined prognostic value for GBM patients. KEY POINTS: • Three-dimensional segmentation on magnetic resonance images allows the study of geometric measures. • Patients with small width of contrast enhancing areas have better prognosis. • The irregularity of contrast enhancing areas predicts survival in glioblastoma patients.

Brain tumors in eloquent areas: A European multicenter survey of intraoperative mapping techniques, intraoperative seizures occurrence, and antiepileptic drug prophylaxis.

Intraoperative mapping and monitoring techniques for eloquent area tumors are routinely used world wide. Very few data are available regarding mapping and monitoring methods and preferences, intraoperative seizures occurrence and perioperative antiepileptic drug management. A questionnaire was sent to 20 European centers with experience in intraoperative mapping or neurophysiological monitoring for the treatment of eloquent area tumors. Fifteen centers returned the completed questionnaires. Data was available on 2098 patients. 863 patients (41.1%) were operated on through awake surgery and intraoperative mapping, while 1235 patients (58.8%) received asleep surgery and intraoperative electrophysiological monitoring or mapping. There was great heterogeneity between centers with some totally AW oriented (up to 100%) and other almost totally ASL oriented (up to 92%) (31% SD). For awake surgery, 79.9% centers preferred an asleep-awake-asleep anesthesia protocol. Only 53.3% of the centers used ECoG or transcutaneous EEG. The incidence of intraoperative seizures varied significantly between centers, ranging from 2.5% to 54% (p < 0.001). It there appears to be a statistically significant link between the mastery of mapping technique and the risk of intraoperative seizures. Moreover, history of preoperative seizures can significantly increase the risk of intraoperative seizures (p < 0.001). Intraoperative seizures occurrence was similar in patients with or without perioperative drugs (12% vs. 12%, p = 0.2). This is the first European survey to assess intraoperative functional mapping and monitoring protocols and the management of peri- and intraoperative seizures. This data can help identify specific aspects that need to be investigated in prospective and controlled studies.

Survey on current cognitive practices within the European Low-Grade Glioma Network: towards a European assessment protocol.

BACKGROUND: The European Low-Grade Glioma network indicated a need to better understand common practices regarding the managing of diffuse low-grade gliomas. This area has experienced great advances in recent years. METHOD: A general survey on the managing of diffuse low-grade gliomas was answered by 21 centres in 11 European countries. Here we focused on specific questions regarding perioperative and intraoperative cognitive assessments. RESULTS: More centres referred to the same speech and language therapist and/or neuropsychologist across all assessments; a core of assessment tools was routinely used across centres; fluency tasks were commonly used in the perioperative stages, and object naming during surgery; tasks that tapped on attention, executive functions, visuospatial awareness, calculation and emotions were sparsely administered; preoperative assessments were performed 1 month or 1 week before surgery; timing for postoperative assessments varied; finally, more centres recommended early rehabilitation, whenever needed. CONCLUSIONS: There is an emerging trend towards following similar practices for the management of low-grade gliomas in Europe. Our results are descriptive and formalise current discussions in our group. Also, they contribute towards the development of a European assessment protocol.

Very low doses of direct intravenous iron in each session as maintenance therapy in hemodialysis patients.

BACKGROUND: Intravenous (IV) iron supplementation is widely used in hemodialysis (HD) patients to treat their periodic losses. However, the ideal dose and frequency is unknown. The goal of the study is to see if a 20 mg dose of iron IV at the end of each session of HD as iron maintenance is better than the iron prior therapy. We analyze the erythropoiesis activity (EA) and functional iron (FI) after four weeks of treatment. METHODS: In 36 patients, we measure reticulocyte count and content of hemoglobin reticulocyte (CHr) as EA and FI markers, respectively, before and after the treatment. Before the study, 23 patients received another different therapy with IV iron as maintenance therapy. RESULTS: Reticulocyte count: 49.7 ± 23.8 × 10(3) before and 47.2 ± 17.2 × 10(3) after the treatment (p= 0.51). The CHr: 34.8 ± 3.7 pg and 34.4 ± 3.5 pg, respectively, (p= 0.35), showing an excellent correlation with the other FI markers (serum iron r = 0.6; p = 0.001; saturation transferrin r = 0.49; p = 0.004); that is not shown with the serum ferritin (r = 0.23; p = 0.192) or the hepcidin levels (r = 0.22; p = 0.251). There was not a correlation between the C-Reactive Protein, reticulocyte count, and CHr. The 13 patients who did not receive the iron prior to the study showed high FI levels, but not an increased of the serum ferritin or the serum hepcidin levels. CONCLUSIONS: The administration of a small quantity of iron at the end of every HD session keeps the EA and the FI levels and allows reducing the iron overload administered and/or decreasing the iron stores markers in some patients.

Cellular plasticity confers migratory and invasive advantages to a population of glioblastoma-initiating cells that infiltrate peritumoral tissue.

Glioblastoma (GBM) is associated with infiltration of peritumoral (PT) parenchyma by isolated tumor cells that leads to tumor regrowth. Recently, GBM stem-like or initiating cells (GICs) have been identified in the PT area, but whether these GICs have enhanced migratory and invasive capabilities compared with GICs from the tumor mass (TM) is presently unknown. We isolated GICs from the infiltrated PT tissue and the TM of three patients and found that PT cells have an advantage over TM cells in two-dimensional and three-dimensional migration and invasion assays. Interestingly, PT cells display a high plasticity in protrusion formation and cell shape and their migration is insensitive to substrate stiffness, which represent advantages to infiltrate microenvironments of different rigidity. Furthermore, mouse and chicken embryo xenografts revealed that only PT cells showed a dispersed distribution pattern, closely associated to blood vessels. Consistent with cellular plasticity, simultaneous Rac and RhoA activation are required for the enhanced invasive capacity of PT cells. Moreover, Rho GTPase signaling modulators αVß3 and p27 play key roles in GIC invasiveness. Of note, p27 is upregulated in TM cells and inhibits RhoA activity. Gene silencing of p27 increased the invasive capacity of TM GICs. Additionally, ß3 integrin is upregulated in PT cells. Blockade of dimeric integrin αVß3, a Rac activator, reduced the invasive capacity of PT GICs in vitro and abrogated the spreading of PT cells into chicken embryos. Thus, our results describe the invasive features acquired by a unique subpopulation of GICs that infiltrate neighboring tissue.

White matter connections of the supplementary motor area in humans.

INTRODUCTION: The supplementary motor area (SMA) is frequently involved by brain tumours (particularly WHO grade II gliomas). Surgery in this area can be followed by the 'SMA syndrome', characterised by contralateral akinesia and mutism. Knowledge of the connections of the SMA can provide new insights on the genesis of the SMA syndrome, and a better understanding of the challenges related to operating in this region. METHODS: White matter connections of the SMA were studied with both postmortem dissection and advance diffusion imaging tractography. Postmortem dissections were performed according to the Klingler technique. 12 specimens were fixed in 10% formalin and frozen at -15°C for 2 weeks. After thawing, dissection was performed with blunt dissectors. For diffusion tractography, high-resolution diffusion imaging datasets from 10 adult healthy controls from the Human Connectome Project database were used. Whole brain tractography was performed using a spherical deconvolution approach. RESULTS: Five main connections were identified in both postmortem dissections and tractography reconstructions: (1) U-fibres running in the precentral sulcus, connecting the precentral gyrus and the SMA; (2) U-fibres running in the cingulate sulcus, connecting the SMA with the cingulate gyrus; (3) frontal 'aslant' fascicle, directly connecting the SMA with the pars opercularis of the inferior frontal gyrus; (4) medial fibres connecting the SMA with the striatum; and (5) SMA callosal fibres. Good concordance was observed between postmortem dissections and diffusion tractography. CONCLUSIONS: The SMA shows a wide range of white matter connections with motor, language and lymbic areas. Features of the SMA syndrome (akinesia and mutism) can be better understood on the basis of these findings.

Subclinical focal seizures as a sign of progression in gliomas.

BACKGROUND: Subclinical seizures are ictal electrographic discharges lacking signs of clinical seizures, behavioural alteration or subjective symptoms. The diagnosis and detection of this type of non-convulsive seizures remain challenging, and information is scarce regarding this electroclinical picture in subjects with gliomas. The aim of this report is to describe two patients with gliomas who, after treatment with surgery and radiotherapy, exhibited subclinical seizures on video-EEG monitoring, as a manifestation of recurrence or progression of their brain tumour. METHODS: Case report and video-EEG monitoring analysis. RESULTS: Two patients with gliomas were admitted to our neurosurgical unit after a generalized tonic-clonic seizure. Brain MRI revealed a recurrence of their tumour. The use of video-EEG monitoring allowed the detection and characterization of subclinical seizures in both patients that otherwise would have gone undetected. In both cases, subclinical seizures arose from the frontal lobe and were not associated with motor manifestations or subjective symptoms. CONCLUSIONS: We emphasize that the existence of subclinical seizures in patients with gliomas is likely to be underestimated, and can occur in advanced progressive tumours. It is important to carry out continuous video-EEG monitoring in brain tumour patients who have had recent clinical seizures in order to be able to detect subclinical seizures and make appropriate diagnosis.

Subcortical anatomy of the lateral association fascicles of the brain: A review.

Precise knowledge of the connectivities of the different white matter bundles is of great value for neuroscience research. Our knowledge of subcortical anatomy has improved exponentially during recent decades owing to the development of magnetic resonance diffusion tensor imaging tractography (DTI). Although DTI tractography has led to important progress in understanding white matter anatomy, the precise trajectory and cortical connections of the subcortical bundles remain poorly determined. The recent literature was extensively reviewed in order to analyze the trajectories and cortical terminations of the lateral association fibers of the brain.The anatomy of the following tracts is reviewed: superior longitudinal fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, frontal aslant tract, and vertical occipital fasciculus. The functional role of a tract can be inferred from its topography within the brain. Knowing the functional roles of the cortical areas connected by a certain bundle, it is possible to develop new insights into the putative functional properties of such connections.

[Insular-opercular associative tracts: Review of their anatomy and relevance for the trans-opercular approach to the insula]. / Fascículos asociativos ínsulo-operculares: revisión de su anatomía y de las implicaciones para el abordaje transopercular a la ínsula.

INTRODUCTION: The insula is a highly connected area, as an intricate network of afferent and efferent projections connect it with adjacent and distant cortical regions. OBJECTIVE: To perform an extensive review of recent literature to analyse the anatomy of the associative tracts related to the insula. RESULTS: The frontal aslant tract, arcuate fasciculus, horizontal portion of the superior longitudinal fasciculus and the middle longitudinal fasciculus are associative tracts connected to the opercula. The inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus run under the anterior and inferior portion of the insula. CONCLUSIONS: the pars triangularis and orbicularis of the inferior frontal gyrus, as well as the middle and anterior part of the superior temporal gyrus, have few connections with the perisylvian associative network. Consequently, in the trans-opercular approach to the insula, these 2 regions represent anatomical corridors that give access to the insula. The IFOF and the uncinate fasciculus represent the deep functional margin of resection.

Surgical cavity dilatation after resection of IDH-mutated astrocytoma of the mesial temporal lobe: illustrative cases.

BACKGROUND: Space-occupying tumor bed cysts may exceptionally happen after the resection of diffuse low-grade glioma. Their mechanism and management remain debated. The authors report two cases of tumor bed cysts occurring after the resection of a left temporal diffuse low-grade glioma with two different evolutions. OBSERVATIONS: The first patient showed a spontaneous decrease in the cyst volume and did not report any symptoms. In contrast, the second patient showed a progressive increase in the cyst volume and reported headaches and difficulties in finding words. Endoscopic cyst fenestration was performed and led to symptom relief and normalization of the surgical cavity. LESSONS: A tumor bed cyst is a rare complication of temporal low-grade glioma resection. Its formation is due to entrapment of the choroid plexus in the temporal horn widely opened into the surgical cavity. Endoscopic cyst fenestration should be offered only in symptomatic cases. https://thejns.org/doi/10.3171/CASE23674.

Cost-utility of maximal safe resection of WHO grade II gliomas within eloquent areas.

BACKGROUND: Despite the growing use of intraoperative electrical stimulation (IES) mapping for resection of WHO grade II gliomas (GIIG) located within eloquent areas, some authors claim that this is a complex, time-consuming and expensive approach, and not well tolerated by patients, so they rely on other mapping techniques. Here we analyze the health related quality of life, direct and indirect costs of surgeries with and without intraoperative electrical stimulation (IES) mapping for resection of GIIG within eloquent areas. METHODS: A cohort of 11 subjects with GIIG within eloquent areas who had IES while awake (group A) was matched by tumor side and location to a cohort of 11 subjects who had general anesthesia without IES (group B). Direct and indirect costs (measured as loss of labor productivity) and utility (measured in quality adjusted life years, QALYs), were compared between groups. RESULTS: Total mean direct costs per patient were $38,662.70 (range $19,950.70 to $61,626.40) in group A, and $32,116.10 (range $22,764.50 to $46,222.50) in group B (p = 0.279). Total mean indirect costs per patient were $10,640.10 (range $3,010.10 to $86,940.70) in group A, and $48,804.70 (range $3,340.10 to $98,400.60) in group B (p = 0.035). Mean costs per QALY were $12,222.30 (range $3,801.10 to $47,422.90) in group A, and $31,927.10 (range $6,642.90 to $64,196.50) in group B (p = 0.023). CONCLUSIONS: Asleep-awake-asleep craniotomies with IES are associated with an increase in direct costs. However, these initial expenses are ultimately offset by medium and long-term costs averted from a decrease in morbidity and preservation of the patient's professional life. The present study emphasizes the importance to switch to an aggressive and safer surgical strategy in GIIG within eloquent areas.