Impact of intraoperative stimulation mapping on high-grade glioma surgery outcome: a meta-analysis

Onco-functional outcome after resection for eloquent glioblastoma (OFO): A propensity-score matched analysis of an international, multicentre, cohort study

BACKGROUND

The combined impact of complete resection (oncological goal) and no functional loss (functional goal) in glioblastoma subgroups is currently unknown. This study aimed to develop a novel onco-functional outcome (OFO) to merge these two goals into one outcome, resulting in four classes: complete without deficits (OFO1), incomplete without deficits (OFO2), complete with deficits (OFO3), or incomplete with deficits (OFO4).

METHODS

Between 2010-2020, 858 patients with tumor resection for eloquent glioblastoma were included. We analyzed the impact of OFO class on postoperative surgical outcomes using Cox proportional-hazards models with hazard ratios (HR) or logistic regression with odds ratios (OR), followed by specific subgroup analyses. We developed a risk model to predict OFO class preoperatively using logistic regression.

RESULTS

The OFO classification stratified the four OFO classes for overall survival (OS:19.0 versus 14.0 versus 12.0 versus 9.0 months), progression-free survival (PFS), and adjuvant therapy. OFO1 was associated with improved OS [HR= 0.67, (0.55-0.81); p < 0.001], and PFS [HR = 0.68, (0.57-0.81); p < 0.001] in the overall cohort and all clinical and molecular subgroups, except for MGMT-unmethylated tumors; and higher rate of adjuvant therapy [OR= 2.81, (1.71-4.84);p < 0.001]. In patients≥ 70 years, only OFO1 improved their survival outcomes. Safe surgery was especially important in patients with a preoperative KPS ≤ 80 to qualify for adjuvant treatment. Awake craniotomy more often led to OFO1 compared to asleep resection [OR = 1.93, (1.19-3.14); p = 0.008].

CONCLUSIONS

OFO1 was associated with improved OS, PFS, and receipt of adjuvant therapy in all glioblastoma patients with IDH-wildtype and MGMT-methylated tumors. Awake craniotomy was associated with achieving this optimal OFO status. Preventing deficits was more important than complete surgery.

Experiences in Awake Craniotomy from Borneo: A Case Series from Sarawak General Hospital

Background

The indications for awake craniotomy now spans from resection of tumours at eloquent areas of the brain, deep brain stimulation and treatment of aneurysms to name a few. In the region of East Malaysia where patients have various ethnic backgrounds and native languages, planning and execution of these procedures can be somewhat challenging.

Methods

This is a retrospective analysis of 11 awake surgeries conducted by the Department of Neurosurgery in Sarawak. The indications for awake craniotomy surgery in our sample population were intra-axial lesions in eloquent regions involving important cortical areas and subcortical tracts which were at risk of damage during tumour excision. Patients were assessed for intra-operative and post-operative neurological deficits.

Results

Eleven patients aged 20 years old-70 years old were included in this series. All patients were diagnosed with lesions in eloquent areas of the brain requiring surgical excision. Patients were of various ethnic backgrounds. The spoken language of these patients also varied based on their ethnicity. The histopathological diagnosis of nine patients were consistent with gliomas with three being of high grade. Three patients (27%) developed intra-operative deficits that were not present pre-operatively.

Conclusion

This case series serve to demonstrate the feasibility of awake craniotomies even in centres without vast experiences in awake surgeries and ideal adjuncts which in comparison may be readily available in different centres. Although careful patient selection has been emphasised, it is a difficult feat in a region consisting of at least 30 different ethnic groups with distinct languages and cultures.

Safety and Efficacy of Laser Interstitial Thermal Therapy as Upfront Therapy in Primary Glioblastoma and IDH-Mutant Astrocytoma: A Meta-Analysis

Although primary studies have reported the safety and efficacy of LITT as a primary treatment in glioma, they are limited by sample sizes and institutional variation in stereotactic parameters such as temperature and laser power. The current literature has yet to provide pooled statistics on outcomes solely for primary brain tumors according to the 2021 WHO Classification of Tumors of the Central Nervous System (WHO CNS5). In the present study, we identify recent articles on primary CNS neoplasms treated with LITT without prior intervention, focusing on relationships with molecular profile, PFS, and OS. This meta-analysis includes the extraction of data from primary sources across four databases using the Covidence systematic review manager. The pooled data suggest LITT may be a safe primary management option with tumor ablation rates of 94.8% and 84.6% in IDH-wildtype glioblastoma multiforme (GBM) and IDH-mutant astrocytoma, respectively. For IDH-wildtype GBM, the pooled PFS and OS were 5.0 and 9.0 months, respectively. Similar to rates reported in the prior literature, the neurologic and non-neurologic complication rates for IDH-wildtype GBM were 10.3% and 4.8%, respectively. The neurologic and non-neurologic complication rates were somewhat higher in the IDH-mutant astrocytoma cohort at 33% and 8.3%, likely due to a smaller cohort size.

Awake craniotomy for high-grade gliomas - a prospective cohort study in a UK tertiary-centre

BACKGROUND

Studies from the UK reporting on awake craniotomy (AC) include a heterogenous group of patients which limit the evaluation of the true impact of AC in high-grade glioma (HGG) patients. This study aims to report solely the experience and outcomes of AC for HGG surgery from our centre.

METHODS

A prospective review of all patients who underwent AC for HGG from 2013 to 2019 were performed. Data on patient characteristics including but not limited to demographics, pre- and post-operative Karnofsky performance status (KPS), tumour location and volume, type of surgery, extent of resection (EOR), tumour histopathology, intra- and post-operative complications, morbidity, mortality, disease recurrence, progression-free survival (PFS) and overall survival (OS) from the time of surgery were collected.

RESULTS

Fifteen patients (6 males; 9 females; 17 surgeries) underwent AC for HGG (median age = 55 years). Two patients underwent repeat surgeries due to disease recurrence. Median pre- and post-operative KPS score was 90 (range:80-100) and 90 (range:60-100), respectively. The EOR ranges from 60 to 100 % with a minimum of 80 % achieved in 81.3 % cases. Post-operative complications include focal seizures (17.6 %), transient aphasia/dysphasia (17.6 %), permanent motor deficit (11.8 %), transient motor deficit (5.9 %) and transient sensory disturbance (5.9 %). There were no surgery-related mortality or post-operative infection. The median PFS and OS were 13 (95%CI 5-78) and 30 (95%CI 21-78) months, respectively.

CONCLUSION

This is the first study in the UK to solely report outcomes of AC for HGG surgery. Our data demonstrates that AC for HGG in eloquent region is safe, feasible and provides comparable outcomes to those reported in the literature.

Efficacy and Safety of Intraoperative Radiotherapy for High-Grade Gliomas: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

High-grade gliomas (HGGs) are aggressive tumors of the central nervous system that cause significant morbidity and mortality. Despite advances in surgery and radiation therapy (RT), HGG still has a high incidence of recurrence and treatment failure. Intraoperative radiotherapy (IORT) has emerged as a promising therapeutic approach to achieve local tumor control while sparing normal brain tissue from radiation-induced damage.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines to evaluate the use of IORT for HGG. Eligible studies were included based on specific criteria, and data were independently extracted. Outcomes of interest included complications, IORT failure, survival rates at 12 and 24 months, and mortality.

RESULTS

Sixteen studies comprising 436 patients were included. The overall complication rate after IORT was 17%, with significant heterogeneity observed. The IORT failure rate was 77%, while the survival rates at 12 and 24 months were 74% and 24%, respectively. The mortality rate was 62%.

CONCLUSION

This meta-analysis suggests that IORT may be a promising adjuvant treatment for selected patients with HGG. Despite the high rate of complications and treatment failures, the survival outcomes were comparable or even superior to conventional methods. However, the limitations of the study, such as the lack of a control group and small sample sizes, warrant further investigation through prospective randomized controlled trials to better understand the specific patient populations that may benefit most from IORT. However, the limitations of the study, such as the lack of a control group and small sample sizes, warrant further investigation. Notably, the ongoing RP3 trial (NCT02685605) is currently underway, with the aim of providing a more comprehensive understanding of IORT. Moreover, future research should focus on managing complications associated with IORT to improve its safety and efficacy in treating HGG.

Corticocortical Evoked Potentials in Eloquent Brain Tumor Surgery. A Systematic Review

Eloquent brain tumor surgery involves the delicate task of resecting tumors located in regions of the brain responsible for critical functions, such as language, motor control, and sensory perception. Preserving these functions is of paramount importance to maintain the patient's quality of life. Corticocortical evoked potentials (CCEPs) have emerged as a valuable intraoperative monitoring technique that aids in identifying and preserving eloquent cortical areas during surgery. This systematic review aimed to assess the utility of CCEPs in eloquent brain tumor surgery and determine their effectiveness in improving patient outcomes. A comprehensive literature search was conducted using electronic databases, including PubMed/Medline and Scopus. The search strategy identified 11 relevant articles for detailed analysis. The findings of the included studies consistently demonstrated the potential of CCEPs in guiding surgical decision making, minimizing the risk of postoperative neurological deficits, and mapping functional connectivity during surgery. However, further research and standardization are needed to fully establish the clinical benefits and refine the implementation of CCEPs in routine neurosurgical practice.

Awake Versus Asleep Craniotomy for Patients With Eloquent Glioma: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Awake vs asleep craniotomy for patients with eloquent glioma is debatable. This systematic review and meta-analysis sought to compare awake vs asleep craniotomy for the resection of gliomas in the eloquent regions.

METHODS

MEDLINE and PubMed were searched from inception to December 13, 2022. Primary outcomes were the extent of resection (EOR), overall survival (month), progression-free survival (month), and rates of neurological deficit, Karnofsky performance score, and seizure freedom at the 3-month follow-up. Secondary outcomes were duration of operation (minute) and length of hospital stay (LOS) (day).

RESULTS

Fifteen studies yielded 2032 patients, from which 800 (39.4%) and 1232 (60.6%) underwent awake and asleep craniotomy, respectively. The meta-analysis concluded that the awake group had greater EOR (mean difference [MD] = MD = 8.52 [4.28, 12.76], P < .00001), overall survival (MD = 2.86 months [1.35, 4.37], P = .0002), progression-free survival (MD = 5.69 months [0.75, 10.64], P = .02), 3-month postoperative Karnofsky performance score (MD = 13.59 [11.08, 16.09], P < .00001), and 3-month postoperative seizure freedom (odds ratio = 8.72 [3.39, 22.39], P < .00001). Furthermore, the awake group had lower 3-month postoperative neurological deficit (odds ratio = 0.47 [0.28, 0.78], P = .004) and shorter LOS (MD = -2.99 days [-5.09, -0.88], P = .005). In addition, the duration of operation was similar between the groups (MD = 37.88 minutes [-34.09, 109.86], P = .30).

CONCLUSION

Awake craniotomy for gliomas in the eloquent regions benefits EOR, survival, postoperative neurofunctional outcomes, and LOS. When feasible, the authors recommend awake craniotomy for surgical resection of gliomas in the eloquent regions.

Surgical Management and Advances in the Treatment of Glioma

The care of patients with both high-grade glioma and low-grade glioma necessitates an interdisciplinary collaboration between neurosurgeons, neuro-oncologists, neurologists and other practitioners. In this review, we aim to detail the considerations, approaches and advances in the neurosurgical care of gliomas. We describe the impact of extent-of-resection in high-grade and low-grade glioma, with particular focus on primary and recurrent glioblastoma. We address advances in surgical methods and adjunct technologies such as intraoperative imaging and fluorescence guided surgery that maximize extent-of-resection while minimizing the potential for iatrogenic neurological deficits. Finally, we review surgically-mediated therapies other than resection and discuss the role of neurosurgery in emerging paradigm-shifts in inter-disciplinary glioma management such as serial tissue sampling and "window of opportunity trials".

Nanobubble-mediated cancer cell sonoporation using low-frequency ultrasound

Ultrasound insonation of microbubbles can form transient pores in cell membranes that enable the delivery of non-permeable extracellular molecules to the cells. Reducing the size of microbubble contrast agents to the nanometer range could facilitate cancer sonoporation. This size reduction can enhance the extravasation of nanobubbles into tumors after an intravenous injection, thus providing a noninvasive sonoporation platform. However, drug delivery efficacy depends on the oscillations of the bubbles, the ultrasound parameters and the size of the target compared to the membrane pores. The formation of large pores is advantageous for the delivery of large molecules, however the small size of the nanobubbles limit the bioeffects when operating near the nanobubble resonance frequency at the MHz range. Here, we show that by coupling nanobubbles with 250 kHz low frequency ultrasound, high amplitude oscillations can be achieved, which facilitate low energy sonoporation of cancer cells. This is beneficial both for increasing the uptake of a specific molecule and to improve large molecule delivery. The method was optimized for the delivery of four fluorescent molecules ranging in size from 1.2 to 70 kDa to breast cancer cells, while comparing the results to targeted microbubbles. Depending on the fluorescent molecule size, the optimal ultrasound peak negative pressure was found to range between 300 and 500 kPa. Increasing the pressure to 800 kPa reduced the fraction of fluorescent cells for all molecules sizes. The optimal uptake for the smaller molecule size of 4 kDa resulted in a fraction of 19.9 ± 1.8% of fluorescent cells, whereas delivery of 20 kDa and 70 kDa molecules yielded 14 ± 0.8% and 4.1 ± 1.1%, respectively. These values were similar to targeted microbubble-mediated sonoporation, suggesting that nanobubbles can serve as noninvasive sonoporation agents with a similar potency, and at a reduced bubble size. The nanobubbles effectively reduced cell viability and may thus potentially reduce the tumor burden, which is crucial for the success of cancer treatment. This method provides a non-invasive and low-energy tumor sonoporation theranostic platform, which can be combined with other therapies to maximize the therapeutic benefits of cancer treatment or be harnessed in gene therapy applications.

Awake craniotomy in epilepsy surgery includes previously inoperable patients with preserved efficiency and safety

Introduction: Whilst awake craniotomy has been widely used historically in epilepsy surgery, the safety and efficacy of this approach in epilepsy surgery has been sparsely investigated in controlled studies. The objective of this study is to investigate the safety and efficacy of awake resection in epilepsy surgery and focuses on the possibility to widen surgical indications with awake surgery. Methods: Fifteen patients operated with awake epilepsy surgery were compared to 30 matched controls undergoing conventional/asleep epilepsy surgery. The groups were compared with regard to neurological complications, seizure control and location of resection. Results: Regarding seizure control, 86% of patients in the awake group reached Engel grade 1-2 compared to 73% in the control group, operated with conventional/asleep surgery, not a statistically significant difference. Neither was there a statistical significant difference regarding postoperative neurological complications. However, there was a significant difference in location of the resection when comparing the two groups. Of the 15 patients operated with awake intraoperative mapping, four had previously been considered as non-operable by epilepsy surgery centres, due to vicinity to eloquent brain regions and predicted risk of post-operative neurological deficits. Discussion: The results show that awake epilepsy surgery yields similar level of seizure control when compared to conventional asleep surgery, with maintained safety in regard to neurological complications. Furthermore, the results indicate that awake craniotomy in epilepsy surgery is feasible and possible in patients otherwise regarded as inoperable with epileptigenic zone in proximity to eloquent brain structures.

Technical Aspects of Motor and Language Mapping in Glioma Patients

Gliomas are infiltrative primary brain tumors that often invade functional cortical and subcortical regions, and they mandate individualized brain mapping strategies to avoid postoperative neurological deficits. It is well known that maximal safe resection significantly improves survival, while postoperative deficits minimize the benefits associated with aggressive resections and diminish patients’ quality of life. Although non-invasive imaging tools serve as useful adjuncts, intraoperative stimulation mapping (ISM) is the gold standard for identifying functional cortical and subcortical regions and minimizing morbidity during these challenging resections. Current mapping methods rely on the use of low-frequency and high-frequency stimulation, delivered with monopolar or bipolar probes either directly to the cortical surface or to the subcortical white matter structures. Stimulation effects can be monitored through patient responses during awake mapping procedures and/or with motor-evoked and somatosensory-evoked potentials in patients who are asleep. Depending on the patient’s preoperative status and tumor location and size, neurosurgeons may choose to employ these mapping methods during awake or asleep craniotomies, both of which have their own benefits and challenges. Regardless of which method is used, the goal of intraoperative stimulation is to identify areas of non-functional tissue that can be safely removed to facilitate an approach trajectory to the equator, or center, of the tumor. Recent technological advances have improved ISM’s utility in identifying subcortical structures and minimized the seizure risk associated with cortical stimulation. In this review, we summarize the salient technical aspects of which neurosurgeons should be aware in order to implement intraoperative stimulation mapping effectively and safely during glioma surgery.

Risk Factors and Characteristics of Intraoperative Seizures During Awake Craniotomy: A Retrospective Cohort Study of 562 Consecutive Patients With a Space-occupying Brain Lesion

INTRODUCTION

Intraoperative seizures (IOSs) during awake craniotomy (AC) are associated with significant morbidity. The reported incidence of IOS is between 3% and 30%. The aim of this study was to identify risk factors for IOS during AC for elective resection or biopsy of a space-occupying brain lesion.

METHODS

In this retrospective study, we reviewed the records of all awake craniotomies performed by a single neurosurgeon at a single university hospital between July 2006 and December 2018. IOS was defined as a clinically apparent seizure that occurred in the operating room and was documented in the medical records. Explanatory variables were chosen based on previously published literature on risk factors for IOS.

RESULTS

Five hundred and sixty-two patients had a total of 607 AC procedures during the study period; 581 cases with complete anesthesia records were included in analysis. Twenty-nine (5.0%) IOS events were reported during 29 (5%) awake craniotomies. Most seizures (27/29; 93%) were focal in nature and did not limit planned intraoperative stimulation mapping. Variables associated with IOS at a univariate P -value <0.1 (frontal location of tumor, preoperative radiotherapy, preoperative use of antiepileptic drugs, intraoperative use of dexmedetomidine, and intraoperative stimulation mapping) were included in a multivariable logistic regression. Frontal location of tumor (adjusted odds ratio: 5.68, 95% confidence interval: 2.11-15.30) and intraoperative dexmedetomidine use (adjusted odds ratio: 2.724, 95% confidence interval: 1.24-6.00) were independently associated with IOS in the multivariable analysis.

CONCLUSIONS

This study identified a low incidence (5%) of IOS during AC. The association between dexmedetomidine and IOS should be further studied in randomized trials as this is a modifiable risk factor.

Survival, Functional, and Seizure Control Outcomes After Resection of Perirolandic World Health Organization Grade II and III Gliomas: A Single-Center Retrospective Review

OBJECTIVE

We aimed to assess, in patients with perirolandic gliomas and gliomas originating from other regions, survival, functional outcomes, and seizure control and, in addition, to identify any clinical characteristics predictive of progression-free survival, overall survival, and seizure control.

METHODS

We retrospectively analyzed 87 patients who underwent resection of World Health Organization grade II or III gliomas at a single institution between 2009 and 2021. Tumors were classified by topographic involvement. One-year postoperative functional status was quantified with Karnofsky Performance Status. One-year seizure control was defined by Engel seizure classification. Dichotomous and categorical variables were reported as counts and percentages and compared using Fisher exact test. A Cox regression model was used to identify covariates that affect progression-free survival and overall survival.

RESULTS

Patients with perirolandic gliomas had similar survival and functional outcomes to patients with gliomas from other regions and a low rate of lasting neurologic deficits. Patients with perirolandic gliomas had comparatively worse long-term seizure outcomes (approached statistical significance). Perirolandic involvement (hazard ratio [HR], 0.10; 95% confidence interval [CI], 0.02-0.46; P = 0.005) and preoperative seizures (HR, 0.14; 95% CI, 0.02-0.62; P = 0.017) conferred a lower likelihood of durable seizure control, whereas increased extent of resection (HR, 1.07; 95% CI, 1.03-1.12; P = 0.003) enhanced the likelihood of seizure freedom.

CONCLUSIONS

Despite proximity to or presence in eloquent structures, perirolandic gliomas can largely be resected without incurring worse functional outcomes. Patients with perirolandic gliomas should be considered for maximal safe resection to optimize survival outcomes and improve seizure control.

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.

The current state of the art of primary motor mapping for tumor resection: A focused survey

INTRODUCTION

Cortical and subcortical motor mapping has advanced the notion of maximal safe resection of intra-axial brain tumours, thereby preserving neurological functions as well as improving survival. Despite being an age-old and established neurosurgical procedure across the world, the strategy and techniques involved in motor mapping have a gamut of variation due to a lack of defined standard protocols.

METHODS

We disseminated a structured survey among focused group of neurosurgeons with established practices involving brain mapping. It consisted of 40 questions, split into five sections assessing the practice description, general approach for motor mapping, preference for asleep versus awake mapping, operative techniques and approach to representative tumor cases. Practice-patterns during primary motor mapping for brain tumours were analysed from responses of 51 neurosurgeons.

RESULTS

60.8 % felt that any lesion even near (without infiltration) was suffice to define "involvement" of the cortical/subcortical motor pathways. 82.4 % felt that motor mapping was necessary for brain tumours involving motor pathways, irrespective of the tumor histology or patient age. 90.2 % opined that tumor location was the predominant factor affecting their choice between awake or asleep mapping. 31.4 % believed that all cases should be performed awake unless patient-related medical, psychological, or anaesthetic contraindications exist, whereas 45.1 % felt that all cases should be performed asleep unless language mapping is required. MRI, DTI-based tractography and intra-operative fluorescence were the most commonly employed surgical adjuncts.

CONCLUSIONS

The data from this survey may serve as a preliminary foundation for a more standardized approach to patient selection and the approach to motor mapping for brain tumors.

Effect of Extent of Resection on Survival of Patients with Glioblastoma, IDH-Wild-Type, WHO Grade 4 (WHO 2021): Systematic Review and Meta-Analysis

BACKGROUND

In light of the recently updated World Health Organization (WHO) 2021 central nervous system tumor classifications, the aim of the present study was to establish the effect of the resection extent on overall survival (OS) and progression-free survival (PFS) for patients who met the current diagnostic criteria for glioblastoma, isocitrate dehydrogenase (IDH)-wild-type (WT), WHO grade 4.

METHODS

A systematic literature search was performed using the following databases: PubMed, Web of Science, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews and ClinicalTrials.gov to identify studies that had compared OS and PFS after gross total resection (GTR) versus subtotal resection (STR) or biopsy for glioblastoma IDH-WT.

RESULTS

We identified 1439 studies, of which 9 met the inclusion and/or exclusion criteria. Of the 2023 patients, 788 had undergone GTR. The meta-analysis showed a significant increase in the OS and PFS duration after GTR for glioblastoma IDH-WT, with a median OS of 20 months (95% confidence interval [CI], 17-25) after GTR versus 12 months (95% CI, 9-15) after STR (P < 0.0001). The median PFS was 11 months (95% CI, 9-12) after GTR versus 7 months (95% CI, 5-7) after STR (P < 0.0001). GTR was associated with a 51% reduction in the mortality risk (hazard ratio, 0.49; 95% CI, 0.36-0.65) and a 42% reduction in the progression risk (hazard ratio, 0.58; 95% CI, 0.39-0.88) compared with STR.

CONCLUSIONS

The results from our systematic review suggest that GTR is associated with improved OS and PFS compared with STR for glioblastoma, IDH-WT, WHO grade 4 (WHO 2021). However, our findings were limited by the various study designs and significant clinical and methodologic heterogeneity among the studies.

Functional imaging of the exposed brain

When the brain is exposed, such as after a craniotomy in neurosurgical procedures, we are provided with the unique opportunity for real-time imaging of brain functionality. Real-time functional maps of the exposed brain are vital to ensuring safe and effective navigation during these neurosurgical procedures. However, current neurosurgical practice has yet to fully harness this potential as it pre-dominantly relies on inherently limited techniques such as electrical stimulation to provide functional feedback to guide surgical decision-making. A wealth of especially experimental imaging techniques show unique potential to improve intra-operative decision-making and neurosurgical safety, and as an added bonus, improve our fundamental neuroscientific understanding of human brain function. In this review we compare and contrast close to twenty candidate imaging techniques based on their underlying biological substrate, technical characteristics and ability to meet clinical constraints such as compatibility with surgical workflow. Our review gives insight into the interplay between technical parameters such sampling method, data rate and a technique's real-time imaging potential in the operating room. By the end of the review, the reader will understand why new, real-time volumetric imaging techniques such as functional Ultrasound (fUS) and functional Photoacoustic Computed Tomography (fPACT) hold great clinical potential for procedures in especially highly eloquent areas, despite the higher data rates involved. Finally, we will highlight the neuroscientific perspective on the exposed brain. While different neurosurgical procedures ask for different functional maps to navigate surgical territories, neuroscience potentially benefits from all these maps. In the surgical context we can uniquely combine healthy volunteer studies, lesion studies and even reversible lesion studies in in the same individual. Ultimately, individual cases will build a greater understanding of human brain function in general, which in turn will improve neurosurgeons' future navigational efforts.

Construction of brain area risk map for decision making using surgical navigation and motor evoked potential monitoring information

PURPOSE

Surgical devices or systems typically operate in a stand-alone manner, making it difficult to perform integration analysis of both intraoperative anatomical and functional information. To address this issue, the intraoperative information integration system OPeLiNK^® was developed. The objective of this study is to generate information for decision making using surgical navigation and intraoperative monitoring information accumulated in the OPeLiNK^® database and to analyze its utility.

METHODS

We accumulated intraoperative information from 27 brain tumor patients who underwent resection surgery. First, the risk rank for postoperative paralysis was set according to the attenuation rate and amplitude width of the motor evoked potential (MEP). Then, the MEP and navigation log data were combined and plotted on an intraoperative magnetic resonance image of the individual brain. Finally, statistical parametric mapping (SPM) transformation was performed to generate a standard brain risk map of postoperative paralysis. Additionally, we determined the anatomical high-risk areas using atlases and analyzed the relationship with each set risk rank.

RESULTS

The average distance between the navigation log corresponding to each MEP risk rank and the anatomical high-risk area differed significantly between the with postoperatively paralyzed and without postoperatively paralyzed groups, except for "safe." Furthermore, no excessive deformation was observed resulting from SPM conversion to create the standard brain risk map. There were cases in which no postoperative paralysis occurred even when MEP decreased intraoperatively, and vice versa.

CONCLUSION

The time synchronization reliability of the study data is very high. Therefore, our created risk map can be reported as being functional at indicating the risk areas. Our results suggest that the statistical risks of postoperative complications can be presented for each area where brain surgery is to be performed. In the future, it will be possible to provide surgical navigation with intraoperative support that reflects the risk maps created.

Localization patterns of speech and language errors during awake brain surgery: a systematic review

Awake craniotomy with direct electrical stimulation (DES) is the standard treatment for patients with eloquent area gliomas. DES detects speech and language errors, which indicate functional boundaries that must be maintained to preserve quality of life. During DES, traditional object naming or other linguistic tasks such as tasks from the Dutch Linguistic Intraoperative Protocol (DuLIP) can be used. It is not fully clear which speech and language errors occur in which brain locations. To provide an overview and to update DuLIP, a systematic review was conducted in which 102 studies were included, reporting on speech and language errors and the corresponding brain locations during awake craniotomy with DES in adult glioma patients up until 6 July 2020. The current findings provide a crude overview on language localization. Even though subcortical areas are in general less often investigated intraoperatively, still 40% out of all errors was reported at the subcortical level and almost 60% at the cortical level. Rudimentary localization patterns for different error types were observed and compared to the dual-stream model of language processing and the DuLIP model. While most patterns were similar compared to the models, additional locations were identified for articulation/motor speech, phonology, reading, and writing. Based on these patterns, we propose an updated DuLIP model. This model can be applied for a more adequate "location-to-function" language task selection to assess different linguistic functions during awake craniotomy, to possibly improve intraoperative language monitoring. This could result in a better postoperative language outcome in the future.

The clinical and neurocognitive functional changes with awake brain mapping for gliomas invading eloquent areas: Institutional experience and the utility of The Montreal Cognitive Assessment

Objective

Awake craniotomy with intraoperative brain functional mapping effectively reduces the potential risk of neurological deficits in patients with glioma invading the eloquent areas. However, glioma patients frequently present with impaired neurocognitive function. The present study aimed to investigate the neurocognitive and functional outcomes of glioma patients after awake brain mapping and assess the experience of a tertiary neurosurgical center in China over eight years.

Methods

This retrospective study included 80 patients who underwent awake brain mapping for gliomas invading the eloquent cortex between January 2013 and December 2021. Clinical and surgical factors, such as the extent of resection (EOR), perioperative Karnofsky Performance Score (KPS), progression-free survival (PFS), and overall survival (OS), were evaluated. We also used the Montreal Cognitive Assessment (MoCA) to assess the neurocognitive status changes.

Results

The most frequently observed location of glioma was the frontal lobe (33/80, 41.25%), whereas the tumor primarily invaded the language-related cortex (36/80, 45%). Most patients had supratotal resection (11/80, 13.75%) and total resection (45/80, 56.25%). The median PFS was 43.2 months, and the median OS was 48.9 months in our cohort. The transient (less than seven days) neurological deficit rate was 17.5%, whereas the rate of persistent deficit (lasting for three months) was 15%. At three months of follow-up, most patients (72/80, 90%) had KPS scores > 80. Meanwhile, compared to the preoperative baseline tests, the changes in MoCA scores presented significant improvements at discharge and three months follow-up tests.

Conclusion

Awake brain mapping is a feasible and safe method for treating glioma invading the eloquent cortex, with the benefit of minimizing neurological deficits, increasing EOR, and extending survival time. The results of MoCA test indicated that brain mapping plays a critical role in preserving neurocognitive function during tumor resection.

Speech and Language Errors during Awake Brain Surgery and Postoperative Language Outcome in Glioma Patients: A Systematic Review

Awake craniotomy with direct electrical stimulation (DES) is the standard treatment for patients with gliomas in eloquent areas. Even though language is monitored carefully during surgery, many patients suffer from postoperative aphasia, with negative effects on their quality of life. Some perioperative factors are reported to influence postoperative language outcome. However, the influence of different intraoperative speech and language errors on language outcome is not clear. Therefore, we investigate this relation. A systematic search was performed in which 81 studies were included, reporting speech and language errors during awake craniotomy with DES and postoperative language outcomes in adult glioma patients up until 6 July 2020. The frequencies of intraoperative errors and language status were calculated. Binary logistic regressions were performed. Preoperative language deficits were a significant predictor for postoperative acute (OR = 3.42, p < 0.001) and short-term (OR = 1.95, p = 0.007) language deficits. Intraoperative anomia (OR = 2.09, p = 0.015) and intraoperative production errors (e.g., dysarthria or stuttering; OR = 2.06, p = 0.016) were significant predictors for postoperative acute language deficits. Postoperatively, the language deficits that occurred most often were production deficits and spontaneous speech deficits. To conclude, during surgery, intraoperative anomia and production errors should carry particular weight during decision-making concerning the optimal onco-functional balance for a given patient, and spontaneous speech should be monitored. Further prognostic research could facilitate intraoperative decision-making, leading to fewer or less severe postoperative language deficits and improvement of quality of life.

5-ALA-guided tumor resection during awake speech mapping in gliomas located in eloquent speech areas: Single-center experience

Background

Achieving maximal functionally safe resection of gliomas located within the eloquent speech areas is challenging, and there is a lack of literature on the combined use of 5-aminolevulinic acid (5-ALA) guidance and awake craniotomy.

Objective

The aim of this study was to describe our experience with the simultaneous use of 5-ALA fluorescence and awake speech mapping in patients with left frontal gliomas located within the vicinity of eloquent speech areas.

Materials and methods

A prospectively collected database of patients was reviewed. 5-ALA was administered at a dose of 20 mg/kg 2 h prior to operation, and an operating microscope in BLUE400 mode was used to visualize fluorescence. All patients underwent surgery using the "asleep-awake-asleep" protocol with monopolar and bipolar electrical stimulation to identify the proximity of eloquent cortex and white matter tracts and to guide safe limits of resection along with fluorescence guidance. Speech function was assessed by a trained neuropsychologist before, during, and after surgery.

Results

In 28 patients operated with cortical mapping and 5-ALA guidance (12 Grade 4, 6 Grade 3, and 10 Grade 2 gliomas), Broca's area was identified in 23 cases and Wernicke's area was identified in 5 cases. Fluorescence was present in 14 cases. Six tumors had residual fluorescence due to the positive speech mapping in the tumor bed. Transient aphasia developed in 14 patients, and permanent aphasia developed in 4 patients. In 6 patients operated with cortical and subcortical speech mapping and 5-ALA guidance (4 Grade 4, 1 Grade 3, and 1 Grade 2 gliomas), cortical speech areas were mapped in 5 patients and subcortical tracts were encountered in all cases. In all cases, resection was stopped despite the presence of residual fluorescence due to speech mapping findings. Transient aphasia developed in 6 patients and permanent aphasia developed in 4 patients. In patients with Grade 2-3 gliomas, targeted biopsy of focal fluorescence areas led to upgrading the grade and thus more accurate diagnosis.

Conclusion

5-ALA guidance during awake speech mapping is useful in augmenting the extent of resection for infiltrative high-grade gliomas and identifying foci of anaplasia in non-enhancing gliomas, while maintaining safe limits of functional resection based on speech mapping. Positive 5-ALA fluorescence in diffuse Grade 2 gliomas may be predictive of a more aggressive disease course.

Diffusion tensor imaging, intra-operative neurophysiological monitoring and small craniotomy: Results in a consecutive series of 103 gliomas

Diffusion tensor imaging (DTI) allows visualization of the main white matter tracts while intraoperative neurophysiological monitoring (IONM) represents the gold standard for surgical resection of gliomas. In recent years, the use of small craniotomies has gained popularity thanks to neuronavigation and to the low morbidity rates associated with shorter surgical procedures. The aim of this study was to review a series of patients operated for glioma using DTI, IONM, and tumor-targeted craniotomies. The retrospective analysis included patients with supratentorial glioma who met the following inclusion criteria: preoperative DTI, intraoperative IONM, tumor-targeted craniotomy, pre- and postoperative MRI, and complete clinical charts. The DTI was performed on a 3T scanner. The IONM included electroencephalography (EEG), transcranial (TC) and/or cortical motor-evoked potentials (MEP), electrocorticography (ECoG), and direct electrical stimulation (DES). Outcomes included postoperative neurological deficits, volumetric extent of resection (EOR), and overall survival (OS). One hundred and three patients (61 men, 42 women; mean age 54 ± 14 years) were included and presented the following WHO histologies: 65 grade IV, 19 grade III, and 19 grade II gliomas. After 3 months, only three patients had new neurological deficits. The median postoperative volume was 0cc (IQR 3). The median OS for grade IV gliomas was 15 months, while for low-grade gliomas it was not reached. In our experience, a small craniotomy and a tumor resection supported by IONM and DTI permitted to achieve satisfactory results in terms of neurological outcomes, EOR, and OS for glioma patients.

Surgical Treatment of Glioblastoma: State-of-the-Art and Future Trends

Glioblastoma (GBM) is a highly aggressive disease and is associated with poor prognosis despite treatment advances in recent years. Surgical resection of tumor remains the main therapeutic option when approaching these patients, especially when combined with adjuvant radiochemotherapy. In the present study, we conducted a comprehensive literature review on the state-of-the-art and future trends of the surgical treatment of GBM, emphasizing topics that have been the object of recent study.

The Intraoperative Utilization of Multimodalities Could Improve the Prognosis of Adult Glioblastoma: A Single-Center Observational Study

OBJECTIVE

In recent years, numerous neurosurgical multimodal techniques have been utilized to maximize tumor resection safely and effectively. However, the synergetic effects of neurosurgical multimodalities on the survival of glioblastoma patients remain unclear. This study evaluated the role of intraoperative utilization of multimodalities in glioblastoma patients.

METHODS

Data of 912 adult patients with glioblastoma were obtained from the Huashan Glioma Registry. The utilization of fewer than 2 (multimodality value < 2) intraoperative multimodal techniques was defined as the nonmultimodal group. In contrast, the utilization of 2 or more (multimodality value ≥ 2) intraoperative multimodal techniques was regarded as the multimodal group. The prognosis of the 2 cohorts was compared and further stratified based on the diagnosis date (2010-2014 or 2015-2019) to reveal the role of the application of multimodal techniques.

RESULTS

The median overall survival (OS) and progression-free survival of glioblastoma patients were 17.70 months and 12.03 months, respectively. The OS time of the multimodal group was noticeably longer than that of the nonmultimodal group (21.0 months vs. 16.0 months, P < 0.001). Multimodal techniques were more frequently applied in surgery in the 2015-2019 group than in the 2010-2014 group. The popularity of multimodal techniques contributed to significant improvement in the prognosis of glioblastoma patients from 2010-2014 to 2015-2019 (OS, 16.0 months vs. 22.0 months, P < 0.001).

CONCLUSIONS

This study indicated that the utilization of intraoperative multimodal techniques improved the extent of resection and elevated the survival for adult glioblastoma patients.

Benzodiazepine Sedation and Postoperative Neurological Deficits after Awake Craniotomy for Brain Tumor - An Exploratory Retrospective Cohort Study

An awake craniotomy is a common neurosurgical procedure for excising brain tumor(s) located near or in eloquent areas. The use of benzodiazepine (BZD) for sedation in some patients with neuropathological conditions (e.g., stroke, brain tumors) has been previously linked with re-appearance of neurological deficits including limb incoordination, ataxia, and motor weakness, resulting in complications for the patient along with procedural challenges. Whether or not these findings can be extrapolated to patients undergoing brain tumor resection is largely unknown. The current work primarily sought to compare neurological outcome(s) in the immediate postoperative period between BZD-free and BZD-based sedation techniques in patients undergoing awake craniotomy. Using a database composed of awake craniotomies conducted within a single center and by a single surgeon, patients were retrospectively classified based on midazolam administration into BZD-free sedation (n=125) and BZD-based sedation (n=416) groups. Patients from each group were matched based on age, sex, tumor location, tumor grade, preoperative neurological deficits, non-operative BZD use, and Karnofsky Performance Scale scores, resulting in 108 patients within each group. Postoperative neurological deficits were recorded. Logistic regression analyses were conducted comparing postoperative neurological deficits between the matched groups. Postoperative neurological deficits were more prevalent within the BZD-based sedation group compared to the BZD-free sedation group (adjusted odds ratio (aOR)=1.903, 95% CI=1.018-3.560, p=0.044). In addition, subgroup analysis of the matched cohort showed a relationship between preoperative neurological symptoms and postoperative neurological deficits in the BZD-based sedation group (aOR=3.756, 95% CI=1.390-10.147, p=0.009). Our findings support the notion that the increased incidence of postoperative neurological deficits with BZD sedation may in part be related to the unmasking of preoperative neurological deficits. Further studies are required to confirm this phenomenon.

Reconfiguration from emergency to urgent elective neurosurgery for glioblastoma patients improves length of stay, surgical adjunct use and extent of resective surgery

Background

Glioblastoma (GB) is the most common intrinsic brain cancer and is notorious for its aggressive nature. Despite widespread research and optimization of clinical management, the improvement in overall survival has been limited. The aim of this study was to characterize the impact of service reconfiguration on GB outcomes in a single centre.

Methods

Patients with a histopathological confirmation of a diagnosis of GB between 01/01/2014 and 31/12/2019 were retrospectively identified. Demographic and tumour characteristics, survival, treatment (surgical and oncological), admission status, use of surgical adjunct (5-aminolevulinic acid, intra-operative neuro-monitoring), the length of stay, extent of resection, and surgical complications were recorded from the hospital databases.

Results

From August 2018 the neurosurgical oncology service was reconfigured to manage high-grade tumours on an urgent outpatient basis by surgeons specializing in oncology. We demonstrate that these changes resulted in an increase in elective admissions, greater use of intra-operative adjuncts resulting in the improved extent of tumour resection, and a reduction in median length of stay and associated cost-savings.

Conclusions

Optimizing neuro-oncology patient management through service reconfiguration resulted in increased use of intra-operative adjuncts, improved surgical outcomes, and reduced hospital costs. These changes also have the potential to improve survival and disease-free progression for patients with GB.

Fluorescence-Guided Surgery in Glioblastoma: 5-ALA, SF or Both? Differences between Fluorescent Dyes in 99 Consecutive Cases

Background: Glioblastoma (GBM) is the most common primary brain tumor. The extent of resection (EOR) has been claimed as one of the most important prognostic factors. Fluorescent dyes aid surgeons in detecting a tumor’s borders. 5-aminolevulinic acid (5-ALA) and sodium fluorescein (SF) are the most used. Only a few studies have directly compared these two fluorophores. Methods: A single center retrospective analysis of patients treated for GBM in the period between January 2018 and January 2021 was built to find any differences in terms of EOR, Karnofsky Performance Status (KPS), and overall survival (OS) on the use of 5-ALA, SF, or both. Results: Overall, 99 patients affected by isocitrate dehydrogenase (IDH) wild-type Glioblastoma were included. 5-ALA was administered to 40 patients, SF to 44, and both to 15. No statistically significant associations were identified between the fluorophore and EOR (p = 0.783) or postoperative KPS (p = 0.270). Survival analyses did not show a selective advantage for the use of a given fluorophore (p = 0.184), although there appears to be an advantageous trend associated with the concomitant use of both dyes, particularly after stratification by MGMT (p = 0.071). Conclusions: 5-Ala and SF are equally useful in achieving gross total resection of the enhancing tumor volume. The combination of both fluorophores could lead to an OS advantage.

Longitudinal assessment of network reorganizations and language recovery in postoperative patients with glioma

For patients with glioma located in or adjacent to the linguistic eloquent cortex, awake surgery with an emphasis on the preservation of language function is preferred. However, the brain network basis of postoperative linguistic functional outcomes remains largely unknown. In this work, 34 patients with left cerebral gliomas who underwent awake surgery were assessed for language function and resting-state network properties before and after surgery. We found that there were 28 patients whose language function returned to at least 80% of the baseline scores within 3 months after surgery or to 85% within 6 months after surgery. For these patients, the spontaneous recovery of language function synchronized with changes within the language and cognitive control networks, but not with other networks. Specifically, compared with baseline values, language functions and global network properties were the worst within 1 month after surgery and gradually recovered within 6 months after surgery. The recovery of connections was tumour location dependent and was attributed to both ipsihemispheric and interhemispheric connections. In contrast, for six patients whose language function did not recover well, severe network disruptions were observed before surgery and persisted into the chronic phase. This study suggests the synchronization of functional network normalization and spontaneous language recovery in postoperative patients with glioma.

Safe Surgery for Glioblastoma: Recent Advances and Modern Challenges

One of the major challenges during glioblastoma surgery is balancing between maximizing extent of resection and preventing neurological deficits. Several surgical techniques and adjuncts have been developed to help identify eloquent areas both preoperatively (fMRI, nTMS, MEG, DTI) and intraoperatively (imaging (ultrasound, iMRI), electrostimulation (mapping), cerebral perfusion measurements (fUS)), and visualization (5-ALA, fluoresceine)). In this review, we give an update of the state-of-the-art management of both primary and recurrent glioblastomas. We will review the latest surgical advances, challenges, and approaches that define the onco-neurosurgical practice in a contemporary setting and give an overview of the current prospective scientific efforts.

Defining the impact of adjuvant treatment on the prognosis of patients with inoperable glioblastoma undergoing biopsy only: does the survival benefit outweigh the treatment effort?

Patients with inoperable glioblastoma (GBM) usually experience worse prognosis compared to those in whom gross total resection (GTR) is achievable. Considering the treatment duration and its side effects identification of patients with survival benefit from treatment is essential to guarantee the best achievable quality of life. The aim of this study was to evaluate the survival benefit from radio-chemotherapy and to identify clinical, molecular, and imaging parameters associated with better outcome in patients with biopsied GBMs. Consecutive patients with inoperable GBM who underwent tumor biopsy at our department from 2005 to 2019 were retrospectively analyzed. All patients had histologically confirmed GBM and were followed up until death. The overall survival (OS) was calculated from date of diagnosis to date of death. Clinical, radiological, and molecular predictors of OS were evaluated. A total of 95 patients with biopsied primary GBM were enrolled in the study. The mean age was 64.3 ± 13.2 years; 56.8% (54/95) were male, and 43.2% (41/95) female. Median OS in the entire cohort was 5.5 months. After stratification for adjuvant treatment, a higher median OS was found in the group with adjuvant treatment (7 months, range 2–88) compared to the group without treatment (1 month, range 1–5) log-rank test, p < 0.0001. Patients with inoperable GBM undergoing biopsy indeed experience a very limited OS. Adjuvant treatment is associated with significantly longer OS compared to patients not receiving treatment and should be considered, especially in younger patients with good clinical condition at presentation.

Impact of awake mapping on overall survival and extent of resection in patients with adult diffuse gliomas within or near eloquent areas: a retrospective propensity score-matched analysis of awake craniotomy vs. general anesthesia

PURPOSE

Awake craniotomy (AC) with intraoperative mapping is the best approach to preserve neurological function for glioma surgery in eloquent or near eloquent areas, but whether AC improves the extent of resection (EOR) and overall survival (OS) is controversial. This study aimed to compare the long-term clinical outcomes of glioma resection under AC with those under general anesthesia (GA).

METHODS

Data of 335 patients who underwent surgery with intraoperative magnetic resonance imaging for newly diagnosed gliomas of World Health Organization (WHO) grades II-IV between 2000 and 2013 were reviewed. EOR and OS were quantitatively compared between the AC and GA groups after 1:1 propensity score matching. The two groups were matched for age, preoperative Karnofsky performance status (KPS), tumor location, and pathology.

RESULTS

After propensity score matching, 91 pairs were obtained. The median EOR was 96.1% (interquartile range [IQR] 7.3) and 97.4% (IQR 14.4) in the AC and GA groups, respectively (p = 0.31). Median KPS score 3 months after surgery was 90 (IQR 20) in both groups (p = 0.384). The median survival times were 163.3 months (95% confidence interval [CI] 77.9-248.7) and 143.5 months (95% CI 94.4-192.7) in the AC and GA groups, respectively (p = 0.585).

CONCLUSION

Even if the glioma was within or close to the eloquent area, AC was comparable with GA in terms of EOR and OS. In case of difficulties in randomizing patients with eloquent or near eloquent glioma, our propensity score-matched analysis provides retrospective evidence that AC can obtain EOR and OS equivalent to removing glioma under GA.

Intraoperative hand strength as an indicator of consciousness during awake craniotomy: a prospective, observational study

Awake craniotomy enables mapping and monitoring of brain functions. For successful procedures, rapid awakening and the precise evaluation of consciousness are required. A prospective, observational study conducted to test whether intraoperative hand strength could be a sensitive indicator of consciousness during the awake phase of awake craniotomy. Twenty-three patients who underwent awake craniotomy were included. Subtle changes of the level of consciousness were assessed by the Japan Coma Scale (JCS). The associations of hand strength on the unaffected side with the predicted plasma concentration (Cp) of propofol, the bispectral index (BIS), and the JCS were analyzed. Hand strength relative to the preoperative maximum hand strength on the unaffected side showed significant correlations with the Cp of propofol (ρ =  − 0.219, p = 0.007), the BIS (ρ = 0.259, p = 0.002), and the JCS (τ =  − 0.508, p = 0.001). Receiver operating characteristic curve analysis for discriminating JCS 0–1 and JCS ≥ 2 demonstrated that the area under the curve was 0.76 for hand strength, 0.78 for Cp of propofol, and 0.66 for BIS. With a cutoff value of 75% for hand strength, the sensitivity was 0.76, and the specificity was 0.67. These data demonstrated that hand strength is a useful indicator for assessing the intraoperative level of consciousness during awake craniotomy.

Surgical advances in the management of brain metastases

As the epidemiological and clinical burden of brain metastases continues to grow, advances in neurosurgical care are imperative. From standard magnetic resonance imaging (MRI) sequences to functional neuroimaging, preoperative workups for metastatic disease allow high-resolution detection of lesions and at-risk structures, facilitating safe and effective surgical planning. Minimally invasive neurosurgical approaches, including keyhole craniotomies and tubular retractors, optimize the preservation of normal parenchyma without compromising extent of resection. Supramarginal surgery has pushed the boundaries of achieving complete removal of metastases without recurrence, especially in eloquent regions when paired with intraoperative neuromonitoring. Brachytherapy has highlighted the potential of locally delivering therapeutic agents to the resection cavity with high rates of local control. Neuronavigation has become a cornerstone of operative workflow, while intraoperative ultrasound (iUS) and intraoperative brain mapping generate real-time renderings of the brain unaffected by brain shift. Endoscopes, exoscopes, and fluorescent-guided surgery enable increasingly high-definition visualizations of metastatic lesions that were previously difficult to achieve. Pushed forward by these multidisciplinary innovations, neurosurgery has never been a safer, more effective treatment for patients with brain metastases.

The PROGRAM study: awake mapping versus asleep mapping versus no mapping for high-grade glioma resections: study protocol for an international multicenter prospective three-arm cohort study

INTRODUCTION

The main surgical dilemma during glioma resections is the surgeon's inability to accurately identify eloquent areas when the patient is under general anaesthesia without mapping techniques. Intraoperative stimulation mapping (ISM) techniques can be used to maximise extent of resection in eloquent areas yet simultaneously minimise the risk of postoperative neurological deficits. ISM has been widely implemented for low-grade glioma resections backed with ample scientific evidence, but this is not yet the case for high-grade glioma (HGG) resections. Therefore, ISM could thus be of important value in HGG surgery to improve both surgical and clinical outcomes.

METHODS AND ANALYSIS

This study is an international, multicenter, prospective three-arm cohort study of observational nature. Consecutive HGG patients will be operated with awake mapping, asleep mapping or no mapping with a 1:1:1 ratio. Primary endpoints are: (1) proportion of patients with National Institute of Health Stroke Scale deterioration at 6 weeks, 3 months and 6 months after surgery and (2) residual tumour volume of the contrast-enhancing and non-contrast-enhancing part as assessed by a neuroradiologist on postoperative contrast MRI scans. Secondary endpoints are: (1) overall survival and (2) progression-free survival at 12 months after surgery; (3) oncofunctional outcome and (4) frequency and severity of serious adverse events in each arm. Total duration of the study is 5 years. Patient inclusion is 4 years, follow-up is 1 year.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Ethics Committee (METC Zuid-West Holland/Erasmus Medical Center; MEC-2020-0812). The results will be published in peer-reviewed academic journals and disseminated to patient organisations and media.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID number NCT04708171 (PROGRAM-study), NCT03861299 (SAFE-trial).

Acoustically Detonated Microbubbles Coupled with Low Frequency Insonation: Multiparameter Evaluation of Low Energy Mechanical Ablation

Noninvasive ultrasound surgery can be achieved using focused ultrasound to locally affect the targeted site without damaging intervening tissues. Mechanical ablation and histotripsy use short and intense acoustic pulses to destroy the tissue via a purely mechanical effect. Here, we show that coupled with low-frequency excitation, targeted microbubbles can serve as mechanical therapeutic warheads that trigger potent mechanical effects in tumors using focused ultrasound. Upon low frequency excitation (250 kHz and below), high amplitude microbubble oscillations occur at substantially lower pressures as compared to higher MHz ultrasonic frequencies. For example, inertial cavitation was initiated at a pressure of 75 kPa for a center frequency of 80 kHz. Low frequency insonation of targeted microbubbles was then used to achieve low energy tumor cell fractionation at pressures below a mechanical index of 1.9, and in accordance with the Food and Drug Administration guidelines. We demonstrate these capabilities in vitro and in vivo. In cell cultures, cell viability was reduced to 16% at a peak negative pressure of 800 kPa at the 250 kHz frequency (mechanical index of 1.6) and to 10% at a peak negative pressure of 250 kPa at a frequency of 80 kHz (mechanical index of 0.9). Following an intratumoral injection of targeted microbubbles into tumor-bearing mice, and coupled with low frequency ultrasound application, significant tumor debulking and cancer cell death was observed. Our findings suggest that reducing the center frequency enhances microbubble-mediated mechanical ablation; thus, this technology provides a unique theranostic platform for safe low energy tumor fractionation, while reducing off-target effects.

Feasibility, Safety and Impact on Overall Survival of Awake Resection for Newly Diagnosed Supratentorial IDH-Wildtype Glioblastomas in Adults

Simple Summary

A few studies have suggested the benefits of awake surgery by maximizing the extent of resection while preserving neurological function and improving survival in high-grade glioma patients. However, the histomolecular heterogeneity in these series, mixing grade 3 with grade 4, and IDH-mutated with IDH-wildtype gliomas, represents a major selection bias that may influence survival analyses. For the first time, in a large homogeneous single-institution cohort of newly diagnosed supratentorial IDH-wildtype glioblastoma in adult patients, we assessed feasibility, safety and efficacy of awake surgery using univariate, multivariate and case-matched analysis. Awake surgery was associated with higher resection rates, lower residual tumor rates, and more supratotal resections than asleep resections, allowed standard radiochemotherapy to be performed systematically within a short time between surgery and radiotherapy, and was an independent predictor of progression-free survival and overall survival in the whole series, together with the extent of resection, MGMT promoter methylation status, and standard.

Abstract

Background: Although awake resection using intraoperative cortico-subcortical functional brain mapping is the benchmark technique for diffuse gliomas within eloquent brain areas, it is still rarely proposed for IDH-wildtype glioblastomas. We have assessed the feasibility, safety, and efficacy of awake resection for IDH-wildtype glioblastomas. Methods: Observational single-institution cohort (2012–2018) of 453 adult patients harboring supratentorial IDH-wildtype glioblastomas who benefited from awake resection, from asleep resection, or from a biopsy. Case matching (1:1) criteria between the awake group and asleep group: gender, age, RTOG-RPA class, tumor side, location and volume and neurosurgeon experience. Results: In patients in the awake resection subgroup (n = 42), supratotal resections were more frequent (21.4% vs. 3.1%, p < 0.0001) while partial resections were less frequent (21.4% vs. 40.1%, p < 0.0001) compared to the asleep (n = 222) resection subgroup. In multivariable analyses, postoperative standard radiochemistry (aHR = 0.04, p < 0.0001), supratotal resection (aHR = 0.27, p = 0.0021), total resection (aHR = 0.43, p < 0.0001), KPS score > 70 (HR = 0.66, p = 0.0013), MGMT promoter methylation (HR = 0.55, p = 0.0031), and awake surgery (HR = 0.54, p = 0.0156) were independent predictors of overall survival. After case matching, a longer overall survival was found for awake resection (HR = 0.47, p = 0.0103). Conclusions: Awake resection is safe, allows larger resections than asleep surgery, and positively impacts overall survival of IDH-wildtype glioblastoma in selected adult patients.

Can Preoperative Mapping with Functional MRI Reduce Morbidity in Brain Tumor Resection? A Systematic Review and Meta-Analysis of 68 Observational Studies

Background Preoperative functional MRI (fMRI) is one of several techniques developed to localize critical brain structures and brain tumors. However, the usefulness of fMRI for preoperative surgical planning and its potential effect on neurologic outcomes remain unclear. Purpose To assess the overall postoperative morbidity among patients with brain tumors by using preoperative fMRI versus surgery without this tool or with use of standard (nonfunctional) neuronavigation. Materials and Methods A systematic review and meta-analysis of studies across major databases from 1946 to June 20, 2020, were conducted. Inclusion criteria were original studies that (a) included patients with brain tumors, (b) performed preoperative neuroimaging workup with fMRI, (c) investigated the usefulness of a preoperative or intraoperative functional neuroimaging technique and used that technique to resect cerebral tumors, and (d) reported postoperative clinical measures. Pooled estimates for adverse event rate (ER) effect size (log ER, log odds ratio, or Hedges g) with 95% CIs were computed by using a random-effects model. Results Sixty-eight studies met eligibility criteria (3280 participants; 58.9% men [1555 of 2641]; mean age, 46 years ± 8 [standard deviation]). Functional deterioration after surgical procedure was less likely to occur when fMRI mapping was performed before the operation (odds ratio, 0.25; 95% CI: 0.12, 0.53; P < .001]), and postsurgical Karnofsky performance status scores were higher in patients who underwent fMRI mapping (Hedges g, 0.66; 95% CI: 0.21, 1.11; P = .004]). Craniotomies for tumor resection performed with preoperative fMRI were associated with a pooled adverse ER of 11% (95% CI: 8.4, 13.1), compared with a 21.0% ER (95% CI: 12.2, 33.5) in patients who did not undergo fMRI mapping. Conclusion From the currently available data, the benefit of preoperative functional MRI planning for the resection of brain tumors appears to reduce postsurgical morbidity, especially when used with other advanced imaging techniques, such as diffusion-tensor imaging, intraoperative MRI, or cortical stimulation. © RSNA, 2021 Online supplemental material is available for this article.

Analysis of risk factors and clinical sequelae of direct electrical cortical stimulation-induced seizures and afterdischarges in patients undergoing awake mapping

OBJECTIVE

Intraoperative stimulation has emerged as a crucial adjunct in neurosurgical oncology, aiding maximal tumor resection while preserving sensorimotor and language function. Despite increasing use in clinical practice of this stimulation, there are limited data on both intraoperative seizure (IS) frequency and the presence of afterdischarges (ADs) in patients undergoing such procedures. The objective of this study was to determine risk factors for IS or ADs, and to determine the clinical consequences of these intraoperative events.

METHODS

A retrospective chart review was performed for patients undergoing awake craniotomy (both first time and repeat) at a single institution from 2013 to 2018. Hypothesized risk factors for ADs/ISs in patients were evaluated for their effect on ADs and ISs, including tumor location, tumor grade (I-IV), genetic markers (isocitrate dehydrogenase 1/2, O 6-methylguanine-DNA methyltransferase [MGMT] promoter methylation, chromosome 1p/19q codeletion), tumor volume, preoperative seizure status (yes/no), and dosage of preoperative antiepileptic drugs for each patient. Clinical outcomes assessed in patients with IS or ADs were duration of surgery, length of stay, presence of perioperative deficits, and postoperative seizures. Chi-square analysis was performed for binary categorical variables, and a Student t-test was used to assess continuous variables.

RESULTS

A total of 229 consecutive patients were included in the analysis. Thirty-five patients (15%) experienced ISs. Thirteen (37%) of these 35 patients had experienced seizures that were appreciated clinically and noted on electrocorticography simultaneously, while 8 patients (23%) experienced ISs that were electrographic alone (no obvious clinical change). MGMT promoter methylation was associated with an increased prevalence of ISs (OR 3.3, 95% CI 1.2-7.8, p = 0.02). Forty patients (18%) experienced ADs. Twenty-three percent of patients (9/40) with ISs had ADs prior to their seizure, although ISs and ADs were not statistically associated (p = 0.16). The presence of ADs appeared to be correlated with a shorter length of stay (5.1 ± 2.6 vs 6.1 ± 3.7 days, p = 0.037). Of the clinical features assessed, none were found to be predictive of ADs. Neither IS nor AD, or the presence of either IS or AD (65/229 patients), was a predictor for increased length of stay, presence of perioperative deficits, or postoperative seizures.

CONCLUSIONS

ISs and ADs, while commonly observed during intraoperative stimulation for brain mapping, do not negatively affect patient outcomes.

Awake Epilepsy Surgery in Patients with Focal Cortical Dysplasia

BACKGROUND

Awake craniotomy (AC) and direct electric stimulation emerged together with epilepsy surgery >80 years ago. The goal of our study was to evaluate the benefits of awake surgery in patients with drug-resistant epilepsy caused by focal cortical dysplasia (FCD) affecting eloquent areas.

METHODS

Our material included 95 patients with drug-resistant epilepsy and FCD, who were operated on between January 2009 and December 2018. These 95 patients were assigned into 3 groups: AC; general anesthesia (GA) with intraoperative neuromonitoring; and GA without intraoperative neuromonitoring. We investigated the following variables: age at surgery, lesion side, eloquent cortex involvement, brain mapping success rate, epilepsy surgery success rate, intraoperative complications, postoperative complications, and intraoperative changes of the preoperative resection plan according to results of the brain mapping by direct electric stimulation.

RESULTS

We found statistically significant differences between the AC and GA groups in the mean age at operation, lesion side, eloquent localization, and postoperative transient neurologic deficit. Seizure outcome in the AC was satisfactory (71% complete seizure control) and comparable to the seizure outcome in the GA groups. Our preoperative plan was changed because of functional constraints in 6 patients (43%) operated on during AC.

CONCLUSIONS

AC during epilepsy surgery for FCD in eloquent areas may change the preoperative plan. The good rate of postoperative seizure control and the absence of permanent postoperative neurologic deficit in our series is the main proof that AC is a useful tool in patients with FCD involving the eloquent cortex.

Intra- and postoperative adverse events in awake craniotomy for intrinsic supratentorial brain tumors

OBJECTIVE

To determine the frequency and consequences of intra- and postoperative adverse events in awake craniotomy for intrinsic supratentorial brain tumors. Despite the growing prevalence of awake craniotomy intra- and postoperative, adverse events related to this surgery are poorly discussed.

METHODS

We studied 25 patients undergoing awake craniotomy with maximum safe resection of intrinsic supratentorial brain tumors in the awake-asleep-awake protocol.

RESULTS

Surgery-related inconveniences occurred in 23 patients (92%), while postoperative adverse events were observed in 17 cases (68%). Seven patients suffered from more than one postoperative complication. The most common surgery-related inconvenience was intraoperative hypertension (8 cases, 32%), followed by discomfort (7 cases, 28%), pain during surgery (5 cases, 20%), and tachycardia (3 cases, 12%). The most common postoperative adverse event was a new language deficit that occurred in 10 cases (40%) and remained permanent in one case (4%). Motor deficits occurred in 36% of cases and were permanent in one case (1%). Seizures were observed in 4 cases (16%) intra- and in 2 cases (8%) postoperatively. Seizures appeared more frequently in patients with multilobar insular-involving gliomas and in patients without prophylactic antiepileptic drug therapy.

CONCLUSIONS

Surgery-related inconveniences and postoperative adverse events occur in most awake craniotomies. The most common intraoperative adverse event is hypertension, pain, and tachycardia. The most frequent postoperative adverse events are new language deficits and new motor deficits.

What effects does awake craniotomy have on functional and survival outcomes for glioblastoma patients?

PURPOSE

Neurosurgeons adopt several different surgical approaches to deal with glioblastomas (GB) located in or near eloquent areas. Some attempt maximal safe resection by awake craniotomy (AC), but doubts persist concerning the real benefits of this type of surgery in this situation. We performed a retrospective study to evaluate the extent of resection (EOR), functional and survival outcomes after AC of patients with GB in critical locations.

METHODS

Forty-six patients with primary GB treated with the Stupp regimen between 2004 and 2019, for whom brain mapping was feasible, were included. We assessed EOR, postoperative language and/or motor deficits three months after AC, progression-free survival (PFS) and overall survival (OS).

RESULTS

Complete resection was achieved in 61% of the 46 GB patients. The median PFS was 6.8 months (CI 6.1; 9.7) and the median OS was 17.6 months (CI 14.8; 34.1). Three months after AC, more than half the patients asymptomatic before surgery remained asymptomatic, and one third of patients with symptoms before surgery experienced improvements in language, but not motor functions. The risk of postoperative deficits was higher in patients with preoperative deficits or incomplete resection. Furthermore, the presence of postoperative deficits was an independent predictive factor for shorter PFS.

CONCLUSION

AC is an option for the resection of GB in critical locations. The observed survival outcomes are typical for GB patients in the Stupp era. However, the success of AC in terms of the recovery or preservation of language and/or motor functions cannot be guaranteed, given the aggressiveness of the tumor.

Awake surgery for right frontal lobe glioma can preserve visuospatial cognition and spatial working memory

PURPOSE

Awake surgery is the standard treatment to preserve motor and language functions. This longitudinal study aimed to evaluate the resection rate and preservation of neurocognitive functions in patients with right frontal lobe glioma who underwent awake surgery.

METHODS

Thirty-three patients (mean age, 48.0 years) with right frontal lobe glioma who underwent awake surgery at our hospital between 2013 and 2019 were included. Fourteen, thirteen, and six cases had WHO classification grades of II, III, and IV, respectively. We evaluated visuospatial cognition (VSC) and spatial working memory (SWM) before and three months after surgery. Relevant brain areas for VSC and SWM were intraoperatively mapped, whenever the task was successfully accomplished. Therefore, patients were divided into an intraoperative evaluation group and a non-evaluation group for each function, and the resection rate and functional outcomes were compared.

RESULTS

The removal rate in the evaluation group for VSC and SWM were similar to that in the non-evaluation group. Chronic impairment rate of VSC was significantly lower in the evaluation than in the non-evaluation group (5.6% vs. 33.3%, p = 0.034). No patient showed postoperative SWM impairment in the evaluation group as opposed to the non-evaluation group (16.7%, p = 0.049). The probability of resection of the deeper posterior part of the middle frontal gyrus, the relevant area of VSC, was higher in the non-evaluation group than in the evaluation group.

CONCLUSIONS

We statistically verified that awake surgery for right frontal lobe glioma results in successful preservation of VSC and SWM with satisfying resection rates.