Awake craniotomy for brain tumors near eloquent cortex: correlation of intraoperative cortical mapping with neurological outcomes in 309 consecutive patients

Intraoperative Use of Functional MRI for Surgical Decision Making after Limited or Infeasible Electrocortical Stimulation Mapping

BACKGROUND AND PURPOSE

Functional magnetic resonance imaging (fMRI) is becoming widely recognized as a key component of preoperative neurosurgical planning, although intraoperative electrocortical stimulation (ECS) is considered the gold standard surgical brain mapping method. However, acquiring and interpreting ECS results can sometimes be challenging. This retrospective study assesses whether intraoperative availability of fMRI impacted surgical decision-making when ECS was problematic or unobtainable.

METHODS

Records were reviewed for 191 patients who underwent presurgical fMRI with fMRI loaded into the neuronavigation system. Four patients were excluded as a bur-hole biopsy was performed. Imaging was acquired at 3 Tesla and analyzed using the general linear model with significantly activated pixels determined via individually determined thresholds. fMRI maps were displayed intraoperatively via commercial neuronavigation systems.

RESULTS

Seventy-one cases were planned ECS; however, 18 (25.35%) of these procedures were either not attempted or aborted/limited due to: seizure (10), patient difficulty cooperating with the ECS mapping (4), scarring/limited dural opening (3), or dural bleeding (1). In all aborted/limited ECS cases, the surgeon continued surgery using fMRI to guide surgical decision-making. There was no significant difference in the incidence of postoperative deficits between cases with completed ECS and those with limited/aborted ECS.

CONCLUSIONS

Preoperative fMRI allowed for continuation of surgery in over one-fourth of patients in which planned ECS was incomplete or impossible, without a significantly different incidence of postoperative deficits compared to the patients with completed ECS. This demonstrates additional value of fMRI beyond presurgical planning, as fMRI data served as a backup method to ECS.

Stimulation-related intraoperative seizures during awake surgery: a review of available evidences

Awake surgery is a well-defined procedure with a very low morbidity. In particular, stimulation-related intraoperative seizure (IOS) is a commonly discussed and serious complication associated with awake surgery. Here, we reviewed the literature on awake surgery and IOS and sought to obtain evidences on the predictive factors of IOS and on the effect of IOS on postoperative outcomes. We conducted a comprehensive search of the Embase, MEDLINE, and Cochrane Central Register of Controlled Trials databases to identify potentially relevant articles from 2000 to 2019. We used combinations of the following search terms: "intraoperative seizure awake craniotomy," "awake surgery seizures," and pertinent associations; the search was restricted to publications in English and only to papers published in the last 20 years. The search returned 141 articles, including 39 papers that reported the IOS rate during awake craniotomy. The reported IOS rates ranged between 0 and 24% (mean, 7.7%). Only few studies have assessed the relationships between awake surgery and IOS, and hence, drawing clear conclusions is difficult. Nevertheless, IOS does not cause permanent and severe postoperative deficits, but can affect the patient's status perioperatively and the hospitalization duration. Anterior tumor location is an important perioperative factor associated with high IOS risk, whereas having seizures at tumor diagnosis does not seem to influence. However, the role of antiepileptic drug administration and prophylaxis remains unclear. In conclusion, given the difficulty in identifying predictors of IOS, we believe that prompt action at onset and awareness of appropriate management methods are vital.

Impact of Multi-modality Monitoring Using Direct Electrical Stimulation to Determine Corticospinal Tract Shift and Integrity in Tumors using the Intraoperative MRI

INTRODUCTION

 Preserving the integrity of the corticospinal tract (CST) while maximizing the extent of tumor resection is one of the key principles of brain tumor surgery to prevent new neurologic deficits. Our goal was to determine the impact of the use of perioperative diffusion tensor imaging (DTI) fiber-tracking protocols for location of the CSTs, in conjunction with intraoperative direct electrical stimulation (DES) on patient neurologic outcomes. The role of combining DES and CST shift in intraoperative magnetic resonance imaging (iMRI) to enhance extent of resection (EOR) has not been studied previously.

METHODS

 A total of 53 patients underwent resection of tumors adjacent to the motor gyrus and the underlying CST between June 5, 2009, and April 16, 2013. All cases were performed in the iMRI (BrainSuite 1.5 T). Preoperative DTI mapping and intraoperative cortical and subcortical DES including postoperative DTI mapping were performed in all patients. There were 32 men and 21 women with 40 high-grade gliomas (76%), 4 low-grade gliomas (8%), and 9 (17%) metastases. Thirty-four patients (64%) were newly diagnosed, and 19 (36%) had a previous resection. There were 31 (59%) right-sided and 22 (42%) left-sided tumors. Eighteen patients (34%) had a re-resection after the first intraoperative scan. Most patients had motor-only mapping, and one patient had both speech and motor mapping. Relative to the resection margin, the CST after the first iMRI was designated as having an outward shift (OS), inward shift (IS), or no shift (NS).

RESULTS

 A gross total resection (GTR) was achieved in 41 patients (77%), subtotal resection in 4 (7.5%), and a partial resection in 8 (15%). Eighteen patients had a re-resection, and the mean EOR increased from 84% to 95% (p = 0.002). Of the 18 patients, 7 had an IS, 8 an OS, and in 3 NS was noted. More patients in the OS group had a GTR compared with the IS or NS groups (p = 0.004). Patients were divided into four groups based on the proximity of the tumor to the CST as measured from the preoperative scan. Group 1 (32%) included patients whose tumors were 0 to 5 mm from the CST based on preoperative scans; group 2 (28%), 6 to 10 mm; group 3 (13%), 11 to 15 mm; and group 4 (26%), 16 to 20 mm, respectively. Patients in group 4 had fewer neurologic complications compared with other groups at 1 and 3 months postoperatively (p = 0.001 and p = 0.007, respectively) despite achieving a similar degree of resection (p = 0.61). Furthermore, the current of intraoperative DES was correlated to the distance of the tumor to the CST, and the regression equation showed a close linear relationship between the two parameters.

CONCLUSIONS

 Combining information about intraoperative CST and DES in the iMRI can enhance resection in brain tumors (77% had a GTR). The relative relationship between the positions of the CST to the resection cavity can be a dynamic process that could further influence the surgeon's decision about the stimulation parameters and EOR. Also, the patients with an OS of the CST relative to the resection cavity had a GTR comparable with the other groups.

Socioeconomic restraints and brain tumor surgery in low-income countries

Healthcare spending has become a grave concern to national budgets worldwide, and to a greater extent in low-income countries. Brain tumors are a serious disease that affects a significant percentage of the population, and thus proper allocation of healthcare provisions for these patients to achieve acceptable outcomes is a must. The authors reviewed patients undergoing craniotomy for tumor resection at their institution for the preceding 3 months. All the methods used for preoperative planning, intraoperative management, and postoperative care of these patients were documented. Compromises to limit spending were made at each stage to limit expenditure, including low-resolution MRI, sparse use of intraoperative monitoring and image guidance, and lack of dedicated postoperative neurocritical ICU. This study included a cohort of 193 patients. The average cost from diagnosis to discharge was $1795 per patient (costs are expressed in USD). On average, there was a mortality rate of 10.5% and a neurological morbidity rate of 14%, of whom only 82.2% improved on discharge or at follow-up. The average length of stay at the hospital for these patients was 9.09 days, with a surgical site infection rate of only 3.5%. The authors believe that despite the great number of financial limitations facing neurosurgical practice in low-income countries, surgery can still be performed with reasonable outcomes.

Risk factors for intraoperative stimulation-related seizures during awake surgery: an analysis of 109 consecutive patients

INTRODUCTION

During surgery for lesions in eloquent areas the goal is to achieve the widest resection possible, without loss of neurological function. Intraoperative seizures may lead to abandonment of the procedure or damages to the patient. Awareness regarding the predictors of IOS would help the surgeon. The aim of this retrospective study was to identify the factors associated with the occurrence of IOS in patients who underwent awake surgery for removal of gliomas in eloquent areas.

METHODS

This was a retrospective analysis of prospectively collected data of 109 patients who underwent awake craniotomy between January 2010 and December 2017 for removal of gliomas. IOS were defined as tonic-clonic seizures or loss of consciousness resulting in communication difficulties with the patient occurring during cortical and subcortical mapping.

RESULTS

A total of 109 patients were included in this study and IOS occurred in 9 (8.2%) patients. Demographic and clinical factors were comparable between patients with and without IOS. In the IOS group, 7 (77.8%) patients had seizures preoperatively and 4 (57.1%) were on more than one perioperative antiepileptic drugs (AED).

CONCLUSIONS

The current series add some hints to the poorly studied IOS risk during awake surgery. The risk of IOS appears to be relatively higher in patients with anteriorly located tumors and in patients operated without intraoperative brain activity monitoring and different patterns of stimulation for language and sensory-motor mapping. Further studies are needed to clarify the role of intraoperative techniques.

Seizure burden pre- and postresection of low-grade gliomas as a predictor of tumor progression in low-grade gliomas

Background

Low-grade gliomas (LGGs) are slow-growing, infiltrative tumors frequently associated with seizures. Predicting which patients will develop early tumor recurrence based on clinical indicators following initial surgical intervention remains a challenge. Seizure recurrence following surgery may be an early indicator of tumor recurrence, especially in patients presenting with increase in seizure frequency.

Methods

This study analyzed 148 patients meeting inclusion criteria (age >18 years, LGG diagnosis, at least 1 seizure event recorded before and after initial surgical intervention). All patients were treated at the Brain and Spine Center at The University of Texas MD Anderson Cancer Center from January 2000 to March 2013. Seizure frequency in a 6-month period before and after tumor resection was categorized as none, 1, few (2 to 3 seizures) or several (>3 seizures). Immediately postoperative seizures (up to 48 hours from surgery) were not included in the analysis.

Results

A total of 116 (78.4%) patients had seizures at initial presentation and most (95%) were started on antiepileptic drugs (AEDs). We found 2 clinical variables with a significant impact on progression-free survival (PFS): Higher seizure frequency during the 6-month postoperative period and seizure frequency increase between the 6-month pre- and the 6-month postoperative periods were both correlated to higher risk of early tumor recurrence (P = .007 and P = .004, respectively).

Conclusion

Seizure frequency following surgical resection of LGGs and the seizure frequency change between the 6-month preoperative and postoperative periods may serve as clinical predictors of early tumor recurrence in patients with LGGs who are also afflicted by seizures.

The Stony Brook awake craniotomy protocol: A technical note

Most current awake craniotomy techniques utilize unnecessarily complicated airway management, and cause discomfort to the patients during the awake phase of the surgery. Our manuscript is written to discuss the neurosurgical and anesthetic techniques that we have developed to optimize awake craniotomy techniques at Stony Brook University Medical Center. We used the frameless Brainlab™ skull-mounted array for stereotactic navigation. Rigid fixation of the skull was avoided. General anesthesia with established airway was used during the "asleep" phase of the surgery. Following the removal of the bone flap and the opening of the dura, the patients were woken up, and the established airway was removed. Cortical mapping was performed to establish a safe entry zone for tumor removal. While the tumors were being removed, we continued motor examination and casual conversation with the patients to ensure safety. Patients were sedated during the remaining phase of the surgery until skin closure. No patient exhibited any neurological deficits or adverse anesthesia outcomes during the postoperative period. The protocol we developed avoids rigid skull fixation and emphasizes flexible intraoperative planning, thereby maximizing patient and physician comfort while allowing for successful tumor resection.

Modern Treatment of Brain Arteriovenous Malformations Using Preoperative Planning Based on Navigated Transcranial Magnetic Stimulation: A Revisitation of the Concept of Eloquence

BACKGROUND

Navigated transcranial magnetic stimulation (nTMS) provides a reliable identification of "eloquent" cortical brain areas. Moreover, it can be used for diffusion tensor imaging fiber tracking of eloquent subcortical tracts. We describe the use of nTMS-based cortical mapping and diffusion tensor imaging fiber tracking for defining the "eloquence" of areas surrounding brain arteriovenous malformations (BAVMs), aiming to improve patient stratification and treatment.

METHODS

We collected data of BAVMs suspected to be in eloquent areas treated between 2017 and 2019, and submitted to nTMS-based reconstruction of motor, language, and visual pathways for the definition of the eloquence of the surrounding brain areas. We describe the nTMS-based approach and analyze its impact on patient stratification and allocation to treatment in comparison with the standard assessment of eloquence based on anatomical landmarks.

RESULTS

Ten patients were included in the study. Preliminarily, 9 BAVMs were suspected to be located in an eloquent area. After nTMS-based mapping, only 5 BAVMs were confirmed to be close to eloquent structures, thus leading to a change of the score for eloquence and of the final BAVMs grading in 60% of patients. Treatment was customized according to nTMS information, and no cases of neurological worsening were observed. Radiological obliteration was complete in 7 cases microsurgically treated, and accounted for about 70% in the remaining 3 patients 1 year after radiosurgical treatment.

CONCLUSIONS

The nTMS-based information allows an accurate stratification and allocation of patients with BAVMs to the most effective treatment according to a modern, customized, neurophysiological identification of the adjacent eloquent brain networks.

Evaluation of Postoperative Deficits following Motor Cortex Tumor Resection using Small Craniotomy

Introduction  Surgical treatment of brain tumors in eloquent areas has always been considered a major challenge because removal-related cortical damage can cause serious functional impairment. However, few studies have investigated the association between small craniotomies and the higher risk of incidence of motor deficits and prolonged recovery time. Here, we analyzed neurologic deficits and the prognostic variables after surgery guided by navigation for motor cortex tumors under general anesthesia. Methods  This was a prospective study that included 47 patients with tumors in the precentral gyrus. All surgeries were performed with neuronavigation and cortical mapping, with direct electrical stimulation of the motor cortex. We evaluated the prognostic evolution of patients with pre- and postoperative Karnofsky Performance Scale using the Eastern Cooperative Oncology Group scale. Results  Complete resection was verified in all 18 cases of metastasis, 13 patients with glioblastoma multiforme, and 5 patients with low-grade gliomas. An analysis of the motor deficits revealed that 11 patients experienced worsening of the deficit on the first day after surgery. Only four patients developed new deficits in the immediate postoperative period, and these improved after 3 weeks. After 3 months, only two patients had deficits that were worse those experienced prior to surgery; both patients had glioblastoma multiforme. Conclusion  In our series, motor deficits prior to surgery were the most important factors associated with persistent postoperative deficits. Small craniotomy with navigation associated with intraoperative brain mapping allowed a safe resection and motor preservation in patients with motor cortex brain tumor.

Preservation of cranial nerve function following awake surgery for benign brain tumors in 22 consecutive patients

BACKGROUND

Preservation of cranial nerve function in patients with benign tumors such as meningiomas and vestibular schwannomas remains difficult following microsurgery.

METHODS

In this study, awake surgery was performed in 22 consecutive patients with meningiomas or vestibular schwannomas that compressed cranial nerves (I-XII). Improved, unchanged, or deteriorated cranial nerve function after surgery was evaluated.

RESULTS

The function of 44 cranial nerves in 22 consecutive patients who underwent awake surgery for meningiomas or vestibular schwannomas improved, was unchanged, or deteriorated in eight, 35, and one nerves, respectively. Regarding the function of the olfactory (Ist) nerve, which is difficult to preserve, hyposmia improved after surgery in two patients with olfactory groove meningiomas. Regarding the auditory (VIIIth) nerve, which is also difficult to preserve, the function was improved, unchanged, or deteriorated after surgery in two, 11, and one patients, respectively, with cerebello-pontine angle meningiomas or vestibular schwannomas. In all patients with serviceable auditory function before surgery, function was preserved after surgery. In the same patients, the function of the facial (VIIth) nerve was also preserved after surgery in all patients.

CONCLUSIONS

These results suggest that awake surgery for benign brain tumors such as meningiomas and vestibular schwannomas is associated with low patient morbidity regarding cranial nerve function.

Awake Surgical Management of Third Ventricular Tumors: A Preliminary Safety, Feasibility, and Clinical Applications Study

BACKGROUND

Endoscopic and microneurosurgical approaches to third ventricular lesions are commonly performed under general anesthesia.

OBJECTIVE

To report our initial experience with awake transsulcal parafascicular corridor surgery (TPCS) of the third ventricle and its safety, feasibility, and limitations.

METHODS

A total of 12 cases are reviewed: 6 colloid cysts, 2 central neurocytomas, 1 papillary craniopharyngioma, 1 basal ganglia glioblastoma, 1 thalamic glioblastoma, and 1 ependymal cyst. Lesions were approached using TPCS through the superior frontal sulcus. Pre-, intra-, and postoperative neurocognitive (NC) testing were performed on all patients.

RESULTS

No cases required conversion to general anesthesia. Awake anesthesia changed intraoperative management in 4/12 cases with intraoperative cognitive changes that required port re-positioning; 3/4 recovered. Average length of stay (LOS) was 6.1 d ± 6.6. Excluding 3 outliers who had preoperative NC impairment, the average LOS was 2.5 d ± 1.2. Average operative time was 3.00 h ± 0.44. Average awake anesthesia time was 5.05 h ± 0.54. There were no mortalities.

CONCLUSION

This report demonstrated the feasibility and safety of awake third ventricular surgery, and was not limited by pathology, size, or vascularity. The most significant factor impacting LOS was preoperative NC deficit. The most significant risk factor predicting a permanent NC deficit was preoperative 2/3 domain impairment combined with radiologic evidence of invasion of limbic structures – defined as a “NC resilience/reserve” in our surgical algorithm. Larger efficacy studies will be required to demonstrate the validity of the algorithm and impact on long-term cognitive outcomes, as well as generalizability of awake TPCS for third ventricular surgery.

Mass Effect Deformation Heterogeneity (MEDH) on Gadolinium-contrast T1-weighted MRI is associated with decreased survival in patients with right cerebral hemisphere Glioblastoma: A feasibility study

Subtle tissue deformations caused by mass-effect in Glioblastoma (GBM) are often not visually evident, and may cause neurological deficits, impacting survival. Radiomic features provide sub-visual quantitative measures to uncover disease characteristics. We present a new radiomic feature to capture mass effect-induced deformations in the brain on Gadolinium-contrast (Gd-C) T1w-MRI, and their impact on survival. Our rationale is that larger variations in deformation within functionally eloquent areas of the contralateral hemisphere are likely related to decreased survival. Displacements in the cortical and subcortical structures were measured by aligning the Gd-C T1w-MRI to a healthy atlas. The variance of deformation magnitudes was measured and defined as Mass Effect Deformation Heterogeneity (MEDH) within the brain structures. MEDH values were then correlated with overall-survival of 89 subjects on the discovery cohort, with tumors on the right (n = 41) and left (n = 48) cerebral hemispheres, and evaluated on a hold-out cohort (n = 49 subjects). On both cohorts, decreased survival time was found to be associated with increased MEDH in areas of language comprehension, social cognition, visual perception, emotion, somato-sensory, cognitive and motor-control functions, particularly in the memory areas in the left-hemisphere. Our results suggest that higher MEDH in functionally eloquent areas of the left-hemisphere due to GBM in the right-hemisphere may be associated with poor-survival.

Mapping in Low-Grade Glioma Surgery: Low- and High-Frequency Stimulation

Surgery for lower grade glioma requires the use of brain mapping techniques to identify functional boundaries, which represent the limit of the resection. Two stimulation paradigms are currently available and their use should be tailored to the clinical context to extend tumor removal and decrease the odds of postoperative permanent deficits.

Impact of connectivity between the pars triangularis and orbitalis on identifying the frontal language area in patients with dominant frontal gliomas

We have previously revealed that identification of the frontal language area (FLA) can be difficult in patients with dominant frontal glioma involving the pars triangularis (PT). The present study added new cases and performed additional analyses. We noticed a new finding that the presence of extension to the pars orbitalis (POr) was associated with negative response to the FLA. The aim of the present study was to evaluate the impact of PT involvement with extension to the POr on the failure to identify the FLA. From 2000 to 2017, awake craniotomy was performed on 470 patients. Of these patients, the present study included 148 consecutive patients with frontal glioma on the dominant side. We evaluated whether tumors involved the PT or extended to the POr. Thirty one of 148 patients showed involvement of the PT, and we examined the detailed characteristics of these 31 patients. The rate of negative response for the FLA was 61% in patients with involvement of the PT. In 31 patients with frontal glioma involving the PT, univariate analyses showed significant correlation between extension to the POr and failure to identify the FLA (P = 0.0070). Similarly, multivariate analysis showed only extension to the POr correlated significantly with failure to identify the FLA (P = 0.0129). We found new evidence that extension to the POr which impacts connectivity between the PT and POr correlated significantly with negative response to the FLA of patients with dominant frontal glioma.

Awake craniotomy in glioma surgery: is it necessary?

INTRODUCTION

The awake craniotomy has evolved from its humble beginnings in ancient cultures to become one of the most eloquent modern neurosurgical procedures. The development of intraoperative mapping techniques like direct electrostimulation of the cortex and subcortical white matter have further argued for its place in the neurosurgeon's armamentarium. Yet the suitability of the awake craniotomy with intraoperative functional mapping (ACWM) to optimize oncofunctional balance after peri-eloquent glioma resection continues to be a topic of active investigation as new methods of intraoperative monitoring and some unfavorable outcome data question its necessity.

EVIDENCE ACQUISITION

The neurosurgery and anesthesiology literatures were scoured for English-language studies that analyzed or reviewed the ACWM or its components as applied to glioma surgery via the PubMed, ClinicalKey, and OvidMEDLINE® databases or via direct online searches of journal archives.

EVIDENCE SYNTHESIS

Information on background, conceptualization, standard techniques, and outcomes of the ACWM were provided and compared. We parceled the procedure into its components and qualitatively described positive and negative outcome data for each. Findings were presented in the context of each study without attempt at quantitative analysis or reconciliation of heterogeneity between studies. Certain illustrative studies were highlighted throughout the review. Overarching conclusions were drawn based on level of evidence, expert opinion, and predominate concordance of data across studies in the literature.

CONCLUSIONS

Most investigators and studies agree that the ACWM is the best currently available approach to optimize oncofunctional balance in this difficult-to-treat patient population. This qualitative review synthesizes the most currently available data on the topic to provide contemporaneous insight into how and why the ACWM has become a favorite operation of neurosurgeons worldwide for the resection of gliomas from eloquent brain.

The effect of tumor removal via craniotomies on preoperative hydrocephalus in adult patients with intracranial tumors

The efficacy of tumor removal via craniotomies on preoperative hydrocephalus (HC) in adult patients with intracranial tumors is largely unknown. Therefore, we sought to evaluate the effect of tumor resection in patients with preoperative HC and identify the incidence and risk factors for postoperative VP shunt dependency. All craniotomies for intracranial tumors at Oslo University Hospital in patients ≥ 18 years old during a 10-year period (2004-2013) were reviewed. Patients with radiologically confirmed HC requiring surgery and subsequent development of shunt dependency were identified by cross-linking our prospectively collected tumor database to surgical procedure codes for hydrocephalus treatment (AAF). Patients with preexisting ventriculoperitoneal (VP) shunts (N = 41) were excluded. From 4774 craniotomies performed on 4204 patients, a total of 373 patients (7.8%) with HC preoperatively were identified. Median age was 54.4 years (range 18.1-83.9 years). None were lost to follow-up. Of these, 10.5% (39/373) required permanent CSF shunting due to persisting postoperative HC. The risk of becoming VP shunt dependent in patients with preexisting HC was 7.0% (26/373) within 30 days and 8.9% (33/373) within 90 days. Only secondary (repeat) surgery was a significant risk factor for VP shunt dependency. In this large, contemporary, single-institution consecutive series, 10.5% of intracranial tumor patients with preoperative HC became shunt-dependent post-craniotomy, yielding a surgical cure rate for HC of 89.5%. To the best of our knowledge, this is the first and largest study regarding postoperative shunt dependency after craniotomies for intracranial tumors, and can serve as benchmark for future studies.

A surgical strategy for lower grade gliomas using intraoperative molecular diagnosis

Lower grade gliomas are both treated and diagnosed via surgical resection. Maximum tumor resection is currently the standard of care; however, this risks the loss of brain function. Glioma can be genetically subdivided into three different types, based on isocitrate dehydrogenase (IDH) mutation status and the presence of 1p/19q codeletion, which have radically different prognoses and responses to adjuvant therapies. Therefore, the means to identify the subtype and evaluate the surrounding tissues during surgery would be advantageous. In this study, we have developed a new surgical strategy for lower grade glioma based on the fourth edition of the World Health Organization Brain Tumor Classification, involving intraoperative molecular diagnosis. High-resolution melting analysis was used to evaluate IDH mutational status, while rapid immunohistochemistry of p53 and alpha-thalassemia/mental retardation syndrome X-linked (ATRX) was used to evaluate the 1p/19q codeletion status, allowing genetic classification during surgery. In addition, intraoperative flow cytometry was used to evaluate the surgical cavity for additional tumor lesions, allowing maximal resection while mitigating the risk of functional losses. This strategy allows the rapid intraoperative diagnosis and mapping of lower grade gliomas, and its clinical use could dramatically improve its prognosis.

Intraoperative linguistic performance during awake brain surgery predicts postoperative linguistic deficits

Introduction

Awake craniotomy pursues a balance between extensive tumor resection and preservation of postoperative language function. A dilemma exists in patients whose tumor resection is restricted due to signs of language impairment observed during awake craniotomy. In order to determine the degree to which recovery of language function caused by tumor resection can be achieved by spontaneous neuroplasticity, the change in postoperative language function was compared to quantified intraoperative linguistic performance.

Methods

The modified, short-form Boston Diagnostic Aphasia Examination (sfBDAE) was used to assess pre- and postoperative language functions; visual object naming (DO 80) and semantic-association (Pyramid and Palm Tree Test, PPTT) tests assessed intraoperative linguistic performance. DO 80 and PPTT were performed alternatively during subcortical functional monitoring while performing tumor resection and sfBDAE was assessed 1-week postoperatively.

Results

Most patients with observed language impairment during awake surgery showed improved language function postoperatively. Both intraoperative DO 80 and PPTT showed significant correlation to postoperative sfBDAE domain scores (p < 0.05), with a higher correlation observed with PPTT. A linear regression model showed that only PPTT predicted the postoperative sfBDAE domain scores with the adjusted R² ranging from 0.51 to 0.89 (all p < 0.01). Receiver operating characteristic analysis showed a cutoff value of PPTT that yielded a sensitivity of 80% and specificity of 100%.

Conclusion

PPTT may be a feasible tool for intraoperative linguistic evaluation that can predict postoperative language outcomes. Further studies are needed to determine the extent of tumor resection that optimizes the postoperative language following neuroplasticity.

Awake Craniotomy vs Craniotomy Under General Anesthesia for Perirolandic Gliomas: Evaluating Perioperative Complications and Extent of Resection

BACKGROUND

A craniotomy with direct cortical/subcortical stimulation either awake or under general anesthesia (GA) present 2 approaches for removing eloquent region tumors. With a reported higher prevalence of intraoperative seizures occurring during awake resections of perirolandic lesions, oftentimes, surgery under GA is chosen for these lesions.

OBJECTIVE

To evaluate a single-surgeon's experience with awake craniotomies (AC) vs surgery under GA for resecting perirolandic, eloquent, motor-region gliomas.

METHODS

Between 2005 and 2015, a retrospective analysis of 27 patients with perirolandic, eloquent, motor-area gliomas that underwent an AC were case-control matched with 31 patients who underwent surgery under GA for gliomas in the same location. All patients underwent direct brain stimulation with neuromonitoring and perioperative risk factors, extent of resection, complications, and discharge status were assessed.

RESULTS

The postoperative Karnofsky Performance Score (KPS) was significantly lower for the GA patients at 81.1 compared to the AC patients at 93.3 ( P = .040). The extent of resection for GA patients was 79.6% while the AC patients had an 86.3% resection ( P = .136). There were significantly more 100% total resections in the AC patients 25.9% compared to the GA group (6.5%; P = .041). Patients in the GA group had a longer mean length of hospitalization of 7.9 days compared to the AC group at 4.2 days ( P = .049).

CONCLUSION

We show that AC can be performed with more frequent total resections, better postoperative KPS, shorter hospitalizations, as well as similar perioperative complication rates compared to surgery under GA for perirolandic, eloquent motor-region glioma.

Technical Aspects of Awake Craniotomy with Mapping for Brain Tumors in a Limited Resource Setting

BACKGROUND

Brain tumor surgery near or within eloquent regions is increasingly common and is associated with a high risk of neurologic injury. Awake craniotomy with mapping has been shown to be a valid method to preserve neurologic function and increase the extent of resection. However, the technique used varies greatly among centers. Most count on professionals such as neuropsychologists, speech therapists, neurophysiologists, or neurologists to help in intraoperative patient evaluation. We describe our technique with the sole participation of neurosurgeons and anesthesiologists.

METHODS

A retrospective review of 19 patients who underwent awake craniotomies for brain tumors between January 2013 and February 2017 at a tertiary university hospital was performed. We sought to identify and describe the most critical stages involved in this surgery as well as show the complications associated with our technique.

RESULTS

Preoperative preparation, positioning, anesthesia, brain mapping, resection, and management of seizures and pain were stages deemed relevant to the accomplishment of an awake craniotomy. Sixteen percent of the patients developed new postoperative deficit. Seizures occurred in 24%. None led to awake craniotomy failure.

CONCLUSIONS

We provide a thorough description of the technique used in awake craniotomies with mapping used in our institution, where the intraoperative patient evaluation is carried out solely by neurosurgeons and anesthesiologists. The absence of other specialized personnel and equipment does not necessarily preclude successful mapping during awake craniotomy. We hope to provide helpful information for those who wish to offer function-guided tumor resection in their own centers.

Advances in Brain Tumor Surgery for Glioblastoma in Adults

Glioblastoma (GBM) is the most common primary intracranial neoplasia, and is characterized by its extremely poor prognosis. Despite maximum surgery, chemotherapy, and radiation, the histological heterogeneity of GBM makes total eradication impossible, due to residual cancer cells invading the parenchyma, which is not otherwise seen in radiographic images. Even with gross total resection, the heterogeneity and the dormant nature of brain tumor initiating cells allow for therapeutic evasion, contributing to its recurrence and malignant progression, and severely impacting survival. Visual delimitation of the tumor’s margins with common surgical techniques is a challenge faced by many surgeons. In an attempt to achieve optimal safe resection, advances in approaches allowing intraoperative analysis of cancer and non-cancer tissue have been developed and applied in humans resulting in improved outcomes. In addition, functional paradigms based on stimulation techniques to map the brain’s electrical activity have optimized glioma resection in eloquent areas such as the Broca’s, Wernike’s and perirolandic areas. In this review, we will elaborate on the current standard therapy for newly diagnosed and recurrent glioblastoma with a focus on surgical approaches. We will describe current technologies used for glioma resection, such as awake craniotomy, fluorescence guided surgery, laser interstitial thermal therapy and intraoperative mass spectrometry. Additionally, we will describe a newly developed tool that has shown promising results in preclinical experiments for brain cancer: optical coherence tomography.

Pre-operative language ability in patients with presumed low-grade glioma

In patients with low-grade glioma (LGG), language deficits are usually only found and investigated after surgery. Deficits may be present before surgery but to date, studies have yielded varying results regarding the extent of this problem and in what language domains deficits may occur. This study therefore aims to explore the language ability of patients who have recently received a presumptive diagnosis of low-grade glioma, and also to see whether they reported any changes in their language ability before receiving treatment. Twenty-three patients were tested using a comprehensive test battery that consisted of standard aphasia tests and tests of lexical retrieval and high-level language functions. The patients were also asked whether they had noticed any change in their use of language or ability to communicate. The test scores were compared to a matched reference group and to clinical norms. The presumed LGG group performed significantly worse than the reference group on two tests of lexical retrieval. Since five patients after surgery were discovered to have a high-grade glioma, a separate analysis excluding them were performed. These analyses revealed comparable results; however one test of word fluency was no longer significant. Individually, the majority exhibited normal or nearly normal language ability and only a few reported subjective changes in language or ability to communicate. This study shows that patients who have been diagnosed with LGG generally show mild or no language deficits on either objective or subjective assessment.

Practical prognostic score for predicting the extent of resection and neurological outcome of gliomas in the sensorimotor area

OBJECTIVE

In this prospective study, we assessed the utility of a novel prognostic score (PS) in guiding the surgical strategy of patients with sensorimotor area gliomas.

PATIENTS AND METHODS

Form December 2012 to April 2016, we collected data from patients diagnosed with brain gliomas in the sensorimotor area. All the patients had intraoperatively confirmed contiguity or continuity with sensorimotor cortical and subcortical structures. Several clinical and radiological factors were analyzed to generate a PS for each patient (range 1-8). The end-points included the extent of resection (EOR) and neurological outcome (modified Rankin Score; mRS). We assessed the predictive power of the PS using different analyses. Crosstabs analyses and Fisher's exact test (Fet) were used to evaluate the possible predictive parameters, and for the classification of positive or negative outcomes for the chosen proxies; the significance threshold was set at p<0.05.

RESULTS

Using independent t-tests, we compared the mRS at different time points (pre, post, and at 6 months) for 2 subgroups from the total sample using a cut-off PS value of 4. For the EOR, a PS value of ≥5 was predictive of successful outcome, a value of 4 indicated an uncertain outcome, and a value of ≤3 predicted a worse outcome.

CONCLUSIONS

This PS value can be easily used in clinical settings to help predict the functional outcome and EOR in sensorimotor area tumors. Integration with information from fMRI, DTI, and TMS, along with MRI spectroscopy could further enhance the value of this PS.

Operative and Therapeutic Advancements in Breast Cancer Metastases to the Brain

Patients with breast cancer are surviving longer as the state of the art for care advances. Because patients are surviving longer with primary breast cancer, the incidence of secondary metastatic disease has risen. Metastatic breast cancer to the brain was once thought to be universally fatal. While it is still quite lethal, its treatment after diagnosis is increasingly safe and effective. Critical progress has been made in understanding the interaction between breast metastases and the neural niche, neuroimaging of functional anatomy, minimally invasive image-guided brain surgery, characterizing subtypes of breast cancer based on molecular and genetic profiles, and individualized pharmaceuticals and immunotherapies. In this review, we discuss recent advances that have brought us to state-of-the-art management of metastatic breast cancer to the brain.

Preservation of hearing following awake surgery via the retrosigmoid approach for vestibular schwannomas in eight consecutive patients

BACKGROUND

Hearing preservation in patients with vestibular schwannomas remains difficult by microsurgery or radiosurgery.

METHOD

In this study, awake surgery via the retrosigmoid approach was performed for vestibular schwannomas (volume, 11.6 ± 11.2 ml; range, 1.3-26.4 ml) in eight consecutive patients with preoperative quartering of pure tone audiometry (PTA) of 53 ± 27 dB.

RESULTS

After surgery, hearing was preserved in seven patients and improved in one patient. The postoperative quartering PTA was 51 ± 21 dB. Serviceable hearing (class A + B + C) using the American Association of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification was preserved in all patients. Preoperative useful hearing (AAO-HNS class A + B) was observed in three patients, and useful hearing was preserved in all three of these patients after surgery. In addition, useful facial nerve function (House-Blackmann Grade 1) was preserved in all patients.

CONCLUSIONS

These results suggest that awake surgery for vestibular schwannomas is associated with low patient morbidity, including with respect to hearing and facial nerve function.

The Prognostic Impact of Ventricular Opening in Glioblastoma Surgery: A Retrospective Single Center Analysis

OBJECTIVE

Ventricular opening during glioblastoma (GBM) resection is controversial. Sufficient evidence regarding its prognostic role is missing. We investigated the impact of ventricular opening on overall survival (OS), hydrocephalus development, and postoperative morbidity in patients with GBM.

METHODS

Patients who underwent primary GBM resection between 2006 and 2013 were assessed retrospectively. Established predictors for overall survival (age, Karnofsky Performance Status, extent of resection, O-6-methylguanine-DNA methyltransferase promoter methylation status, isocitrate dehydrogenase mutation status) and further clinical data (postoperative status, further treatment, preoperative tumor volume, proximity to the ventricle) were included in univariate and multivariate analyses.

RESULTS

Thirteen (5.7%) of 229 patients developed a hydrocephalus. Multivariate logistic regression showed that neither ventricular opening, tumor size, proximity to the ventricle, nor extent of resection were significant risk factors for hydrocephalus. Ventricular opening did not delay postoperative therapy and was not associated with neurological morbidity. Kaplan-Meier analysis demonstrated that patients who underwent ventricular opening (n = 114) exhibited a median OS of 14.3 months (12.9-16.5), whereas patients who did not undergo ventricular opening (n = 115) exhibited a median OS of 18.6 months (16.1-20.8). However, multivariate Cox regression (n = 134) did not confirm ventricular opening as an independent negative predictor of OS (risk ratio 1.09, P = 0.77). Instead, it showed that a greater preoperative tumor volume >22.8 cm³ was a negative predictor of OS (risk ratio 1.76, P = 0.02).

CONCLUSIONS

Because extent of resection is a strong independent predictor of OS and ventricular opening is safe, neurosurgeons should consider ventricular opening to achieve maximal tumor resection.

Language recovery after epilepsy surgery of the Broca's area

Epilepsy surgery is indicated in select patients with drug-resistant focal epilepsy. Seizure freedom or significant reduction of seizure burden without risking new neurological deficits is the expected goal of epilepsy surgery. Typically, when the seizure onset zone overlaps with eloquent cortex, patients are excluded from surgery. We present a patient with drug-resistant frontal lobe epilepsy who underwent successful surgery with resection of Broca's area, primarily involving the pars triangularis (BA 45). We report transient expressive aphasia followed by recovery of speech. This case provides new insights into adult neuroplasticity of the language network.

Intraoperative Mapping and Monitoring of the Pyramidal Tract Using Endoscopic Depth Electrodes

OBJECTIVE

To evaluate motor function during neuroendoscopic resectioning of deep-seated brain tumors using endoscopically guided depth electrodes.

METHODS

For 12 cases of thalamic tumors, including high-grade gliomas, germinomas, and malignant lymphomas, depth electrodes were inserted using endoscopic guides between the tumor and the pyramidal tract in the thalamus. Motor-evoked potentials (MEPs) were continuously recorded during neuroendoscopic resectioning of the tumors.

RESULTS

Monitoring of MEP responses using depth electrodes in all 12 cases was successful. The minimum stimulus intensity threshold required to induce MEP responses was 3 mA. Gross total or subtotal resections were successful with this technique for all patients with glioma. No additional neurologic impairments were found after surgery in any of the cases.

CONCLUSIONS

Continuous MEP measurement using depth electrodes can serve as a new monitoring technique for endoscopic resectioning of deep-seated brain tumors.

Strategy of Surgical Resection for Glioma Based on Intraoperative Functional Mapping and Monitoring

A growing number of papers have pointed out the relationship between aggressive resection of gliomas and survival prognosis. For maximum resection, the current concept of surgical decision-making is in “information-guided surgery” using multimodal intraoperative information. With this, anatomical information from intraoperative magnetic resonance imaging (MRI) and navigation, functional information from brain mapping and monitoring, and histopathological information must all be taken into account in the new perspective for innovative minimally invasive surgical treatment of glioma. Intraoperative neurofunctional information such as neurophysiological functional monitoring takes the most important part in the process to acquire objective visual data during tumor removal and to integrate these findings as digitized data for intraoperative surgical decision-making. Moreover, the analysis of qualitative data and threshold-setting for quantitative data raise difficult issues in the interpretation and processing of each data type, such as determination of motor evoked potential (MEP) decline, underestimation in tractography, and judgments of patient response for neurofunctional mapping and monitoring during awake craniotomy. Neurofunctional diagnosis of false-positives in these situations may affect the extent of resection, while false-negatives influence intra- and postoperative complication rates. Additionally, even though the various intraoperative visualized data from multiple sources contribute significantly to the reliability of surgical decisions when the information is integrated and provided, it is not uncommon for individual pieces of information to convey opposing suggestions. Such conflicting pieces of information facilitate higher-order decision-making that is dependent on the policies of the facility and the priorities of the patient, as well as the availability of the histopathological characteristics from resected tissue.

A Single-Center Cost Analysis of Treating Primary and Metastatic Brain Cancers with Either Brain Laser Interstitial Thermal Therapy (LITT) or Craniotomy

BACKGROUND

Brain laser interstitial thermal therapy (LITT) under magnetic resonance imaging (MRI) guidance has recently gained US clinical approval for the ablation of soft, neurological tissue. LITT is a minimally invasive alternative to craniotomy.

OBJECTIVE

While safety and efficacy are the focus of most current LITT studies, it is unclear how acute care costs (inpatient care ± aftercare) of LITT compare to craniotomy in an academic medical center. Therefore, the purpose of this analysis is to examine these costs of using brain LITT under MRI guidance compared to craniotomy in complex anatomies.

METHODS

Consecutive patients treated at a single US center from 1 January 2010 to 21 October 2014 were retrospectively evaluated. Patients were included if they had a primary procedure for LITT or craniotomy (International Classification of Diseases, 9th revision, Clinical Modification [ICD-9-CM] procedure code 17.61 or ICD-9-CM procedure code 01.59, respectively) and were subgrouped according to their diagnosis of primary brain or metastatic brain cancer (ICD-9-CM 191.0-191.9 or ICD-9-CM 198.3, respectively). Patients were excluded if they had co-morbid conditions such as brain edema (ICD-9-CM 348.5). Patients were matched (LITT vs. craniotomy) based on diagnosis. Appropriate statistical analyses were undertaken to examine the year 2015 costs for care in all settings (acute hospital and post-hospital care, i.e., skilled nursing facility, rehabilitation, and home care) were examined.

RESULTS

In patients treated for a primary brain cancer, there was no statistical difference in the acute and post-care costs of LITT and craniotomy (inverse variance, mean difference [MD], random effects model): MD = -US$1669; 95% confidence interval (CI) -$8192 to $4854; P = 0.62. When examining difficult to access primary malignancies, no difference was found: MD = -US$4719; 95% CI -$12,183 to $2745; P = 0.22. In metastatic brain cancer, LITT was found to be significantly less costly than craniotomy: MD = -US$6522; 95% CI -$11,911 to -$1133; P = 0.02.

CONCLUSIONS

In patients with metastatic brain cancer, LITT is less costly than craniotomy. Patients receiving LITT had a significantly shorter length of hospital stay, were significantly older, and were more likely to be discharged home. The use of LITT may be a reasonable option in bundled episodes of care for brain cancer and may fit into the Bundled Payment for Care Improvement (BPCI) program being evaluated by Medicare and providers.

Preoperative rTMS Language Mapping in Speech-Eloquent Brain Lesions Resected Under General Anesthesia: A Pair-Matched Cohort Study

OBJECTIVE

The value of preoperative repetitive transcranial magnetic stimulation (rTMS) language mapping for function preservation in surgery of speech-eloquent lesions under general anesthesia remains to be determined.

METHODS

We prospectively enrolled 20 consecutive right-handed patients with a malignant, left-sided perisylvian language-eloquent brain tumor. All patients were subjected to surgical resection under general anesthesia guided by preoperative rTMS language mapping (rTMS group, 2014-2016). A matched-pair analysis with 20 patients who also underwent surgical resection under general anesthesia in the pre-rTMS era (pre-rTMS group, 2009-2013) was performed. Language performance status was ranked from grade 0 to grade 3 (none, mild, medium, severe).

RESULTS

Rates of gross total resection, tumor residual, and complications were equal in both groups. Duration of surgery (P = 0.039) and inpatient stay (P = 0.001) were significantly shorter in the rTMS group. Preoperatively, 14 patients in the rTMS and 13 patients in the pre-rTMS group had language deficits (P = 0.380). One week after surgery, 8/14 patients (57.1%) in the rTMS group but only 1/13 patients (7.7%) in the pre-rTMS group experienced improvement of language performance status (P = 0.013). At 6 weeks follow-up, language performance status was significantly better in the rTMS group (P = 0.048). However, at 3 months follow-up, the rTMS and pre-rTMS groups showed an equal language performance status.

CONCLUSIONS

Implementation of preoperative rTMS language mapping seems to provide a favorable early language outcome in patients undergoing surgical resection of language-eloquent lesions under general anesthesia.

"Next Door" intraoperative magnetic resonance imaging for awake craniotomy: Preliminary experience and technical note

BACKGROUND

During glioma surgery "maximal safe resection" must be the main goal. Intraoperative magnetic resonance imaging (iMRI) associated with awake craniotomy (AC) is a valuable tool to achieve this objective. In this article, AC with a "next-door" iMRI concept is described in a stepwise protocol.

METHODS

This is a retrospective analysis of 18 patients submitted to AC using iMRI; a stepwise protocol is also discussed.

RESULTS

The mean age was 41.7 years. Hemiparesis, aphasia, and seizures were the main initial symptoms of the patients. Sixty-six percent of the tumors were located in the left hemisphere. All tumors were near or within eloquent areas. Fifty-three percent of the cases were glioblastomas multiforme and 47% of the patients had low grade gliomas. The mean surgical time and iMRI time were 4 h 4 min and 30 min, respectively. New resection was performed in 33% after iMRI. Extent of resection (EOR) higher than 95% was possible in 66.7% of the patients. The main reason of EOR lower than 95% was positive mapping of eloquent areas (6 patients). Eighty percent of the patients experienced improvement of their deficits immediately after the surgery or had a stable clinical status whereas 20% had neurological deterioration, however, all of them improved after 30 days.

CONCLUSION

AC associated with "next-door" iMRI is a complex procedure, but if performed using a meticulous technique, it may improve the overall tumor resection and safety of the patients.

The effects of new or worsened postoperative neurological deficits on survival of patients with glioblastoma

OBJECTIVE An increased extent of resection (EOR) has been shown to improve overall survival of patients with glioblastoma (GBM) but has the potential for causing a new postoperative neurological deficit. To investigate the impact of surgical neurological morbidity on survival, the authors performed a retrospective analysis of the clinical data from patients with GBM to quantify the impact of a new neurological deficit on the survival benefit achieved with an increased EOR. METHODS The data from all GBM patients who underwent resection at the University of Florida from 2010 to 2015 with postoperative imaging within 72 hours of surgery were included in the study. Retrospective analysis was performed on clinical outcomes and tumor volumes determined on postoperative and follow-up imaging examinations. RESULTS Overall, 115 patients met the inclusion criteria for the study. Tumor volume at the time of presentation was a median of 59 cm³ (enhanced on T1-weighted MRI scans). The mean EOR (± SD) was 94.2% ± 8.7% (range 59.9%-100%). Almost 30% of patients had a new postoperative neurological deficit, including motor weakness, sensory deficits, language difficulty, visual deficits, confusion, and ataxia. The neurological deficits had resolved in 41% of these patients on subsequent follow-up examinations. The median overall survival was 13.1 months (95% CI 10.9-15.2 months). Using a multipredictor Cox model, the authors observed that increased EOR was associated with improved survival except for patients with smaller tumor volumes (≤ 15 cm³). A residual volume of 2.5 cm³ or less predicted a favorable overall survival. Developing a postoperative neurological deficit significantly affected survival (9.2 months compared with 14.7 months, p = 0.02), even if the neurological deficit had resolved by the first follow-up. However, there was a trend of improved survival among patients with resolution of a neurological deficit by the first follow-up compared with patients with a permanent neurological deficit. Any survival benefit from achieving a 95% EOR was abrogated by the development of a new neurological deficit postoperatively. CONCLUSIONS Developing a new neurological deficit after resection of GBM is associated with a decrease in overall survival. A careful balance between EOR and neurological compromise needs to be taken into account to reduce the likelihood of neurological morbidity from surgery.

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.

Long-term surgical and seizure outcomes of frontal low-grade gliomas

INTRODUCTION

Low-grade gliomas are infrequent lesions requiring special emphasis because of their relatively long follow-up time, and therefore the need for patients' well-being. Surgery provides not only increased survival but also improved quality of life for these patients. The purpose of this study was to present surgical series of frontal low-grade gliomas that were operated in our clinic and to discuss their epileptic and functional outcomes.

METHODS

A series of 40 patients with low-grade glioma (WHO Grade II) were retrospectively analysed for patient characteristics, tumour location, epileptic history, surgery type (awake craniotomy, general anaesthesia), extent of resection and complications.

RESULTS

Tumour was localized to primary motor area in most of the cases (35%, n = 14), 25 patients were operated under general anaesthesia and 15 with awake craniotomy. New deficit rate in the early postoperative period was 32.5% (dysarthria in one patient and motor deficits in 12). Karnofsky scores were ≥90 in 92.5% of the patients at the late follow-up. 31 patients were Engel I (77.5%), 5 were Engel II (12.5%) and 4 were Engel IV (10%) postoperatively.

CONCLUSION

Frontal LGGs are eligible to resect vigorously without persistent functional deficits. Patients with immediate postoperative complications benefit from neuro-rehabilitation. However, pre-existing speech dysfunctions are hard to recover with surgery. Surgical resection ends with favourable epileptic outcomes whereas tumour location may influence the results.

Variability of intraoperative electrostimulation parameters in conscious individuals: language cortex

OBJECTIVE Electrostimulation in awake brain mapping is widely used to guide tumor removal, but methodologies can differ substantially across institutions. The authors studied electrostimulation brain mapping data to characterize the variability of the current intensity threshold across patients and the effect of its variations on the number, type, and surface area of the essential language areas detected. METHODS Over 7 years, the authors prospectively studied 100 adult patients who were undergoing intraoperative brain mapping during resection of left hemisphere tumors. In all 100 cases, the same protocol of electrostimulation brain mapping (a controlled naming task-bipolar stimulation with biphasic square wave pulses of 1-msec duration and 60-Hz trains, maximum train duration 6 sec) and electrocorticography was used to detect essential language areas. RESULTS The minimum positive thresholds of stimulation varied from patient to patient; the mean minimum intensity required to detect interference was 4.46 mA (range 1.5-9 mA), and in a substantial proportion of sites (13.5%) interference was detected only at intensities above 6 mA. The threshold varied within a given patient for different naming areas in 22% of cases. Stimulation of the same naming area with greater intensities led to slight changes in the type of response in 19% of cases and different types of responses in 4.5%. Naming sites detected were located in subcentimeter cortical areas (50% were less than 20 mm²), but their extent varied with the intensity of stimulation. During a brain mapping session, the same intensity of stimulation reproduced the same type of interference in 94% of the cases. There was no statistically significant difference between the mean stimulation intensities required to produce interfereince in the left inferior frontal lobe (Broca's area), the supramarginal gyri, and the posterior temporal region. CONCLUSIONS Intrasubject and intersubject variations of the minimum thresholds of positive naming areas and changes in the type of response and in the size of these areas according to the intensity used may limit the interpretation of data from electrostimulation in awake brain mapping. To optimize the identification of language areas during electrostimulation brain mapping, it is important to use different intensities of stimulation at the maximum possible currents, avoiding afterdischarges. This could refine the clinical results and scientific data derived from these mapping sessions.

A Systematic Review and Meta-Analysis of Studies Examining the Use of Brain Laser Interstitial Thermal Therapy versus Craniotomy for the Treatment of High-Grade Tumors in or near Areas of Eloquence: An Examination of the Extent of Resection and Major Complication Rates Associated with Each Type of Surgery

BACKGROUND

The extent of resection (EOR) of high-grade gliomas (WHO grade III or IV) in or near areas of eloquence is associated with overall patient survival, but with higher major neurocognitive complications.

METHODS

A systematic review and meta-analysis was undertaken of the peer-reviewed literature in order to identify studies which examined EOR or extent of ablation (EOA) and major complications (defined as neurocognitive or functional complications which last >3 months duration after surgery) associated with either brain laser interstitial thermal therapy (LITT) or open craniotomy in high-grade tumors in or near areas of eloquence.

RESULTS

Eight studies on brain LITT (n = 79 patients) and 12 craniotomy studies (n = 1,036 patients) were identified which examined either/both EOR/EOA and complications. Meta-analysis demonstrated an EOA/EOR of 85.4 ± 10.6% with brain LITT versus 77.0 ± 40% with craniotomy (mean difference: 8%; 95% CI: 2-15; p = 0.01; inverse variance, random effects model). Meta-analysis of proportions of major complications for each individual therapy demonstrated major complications of 5.7% (95% CI: 1.8-11.6) and 13.8% (95% CI: 10.3-17.9) for LITT and craniotomy, respectively.

CONCLUSION

In patients presenting with high-grade gliomas in or near areas of eloquence, early results demonstrate that brain LITT may be a viable surgical alternative.

[Awake craniotomy]

Awake craniotomy is a neurosurgical intervention aimed at identifying and preserving the eloquent functional brain areas during resection of tumors located near the cortical and subcortical language centers. This article provides a review of the modern literature devoted to the issue. The anatomical rationale and data of preoperative functional neuroimaging, intraoperative electrophysiological monitoring, and neuropsychological tests as well as the strategy of active surgical intervention are presented. Awake craniotomy is a rapidly developing technique aimed at both preserving speech and motor functions and improving our knowledge in the field of speech psychophysiology.

Anaesthesia Management for Awake Craniotomy: Systematic Review and Meta-Analysis

BACKGROUND

Awake craniotomy (AC) renders an expanded role in functional neurosurgery. Yet, evidence for optimal anaesthesia management remains limited. We aimed to summarise the latest clinical evidence of AC anaesthesia management and explore the relationship of AC failures on the used anaesthesia techniques.

METHODS

Two authors performed independently a systematic search of English articles in PubMed and EMBASE database 1/2007-12/2015. Search included randomised controlled trials (RCTs), observational trials, and case reports (n>4 cases), which reported anaesthetic approach for AC and at least one of our pre-specified outcomes: intraoperative seizures, hypoxia, arterial hypertension, nausea and vomiting, neurological dysfunction, conversion into general anaesthesia and failure of AC. Random effects meta-analysis was used to estimate event rates for four outcomes. Relationship with anaesthesia technique was explored using logistic meta-regression, calculating the odds ratios (OR) and 95% confidence intervals [95%CI].

RESULTS

We have included forty-seven studies. Eighteen reported asleep-awake-asleep technique (SAS), twenty-seven monitored anaesthesia care (MAC), one reported both and one used the awake-awake-awake technique (AAA). Proportions of AC failures, intraoperative seizures, new neurological dysfunction and conversion into general anaesthesia (GA) were 2% [95%CI:1-3], 8% [95%CI:6-11], 17% [95%CI:12-23] and 2% [95%CI:2-3], respectively. Meta-regression of SAS and MAC technique did not reveal any relevant differences between outcomes explained by the technique, except for conversion into GA. Estimated OR comparing SAS to MAC for AC failures was 0.98 [95%CI:0.36-2.69], 1.01 [95%CI:0.52-1.88] for seizures, 1.66 [95%CI:1.35-3.70] for new neurological dysfunction and 2.17 [95%CI:1.22-3.85] for conversion into GA. The latter result has to be interpreted cautiously. It is based on one retrospective high-risk of bias study and significance was abolished in a sensitivity analysis of only prospectively conducted studies.

CONCLUSION

SAS and MAC techniques were feasible and safe, whereas data for AAA technique are limited. Large RCTs are required to prove superiority of one anaesthetic regime for AC.

Continuous physical examination during subcortical resection in awake craniotomy patients: Its usefulness and surgical outcome

OBJECTIVES

To evaluate the value of physical examination as a monitoring tool during subcortical resection in awake craniotomy patients and surgical outcomes.

PATIENTS AND METHODS

Authors reviewed medical records of patients underwent awake craniotomy with continuous physical examination for pathology adjacent to the eloquent area.

RESULTS

Between January 2006 and August 2015, there were 37 patients underwent awake craniotomy with continuous physical examination. Pathology was located in the left cerebral hemisphere in 28 patients (75.7%). Thirty patients (81.1%) had neuroepithelial tumors. Degree of resections were defined as total, subtotal, and partial in 16 (43.2%), 11 (29.7%) and 10 (27.0%) patients, respectively. Median follow up duration was 14 months. The reasons for termination of subcortical resection were divided into 3 groups as follows: 1) by anatomical landmark with the aid of neuronavigation in 20 patients (54%), 2) by reaching subcortical stimulation threshold in 8 patients (21.6%), and 3) by abnormal physical examination in 9 patients (24.3%). Among these 3 groups, there were statistically significant differences in the intraoperative (p=0.002) and early postoperative neurological deficit (p=0.005) with the lowest deficit in neuronavigation group. However, there were no differences in neurological outcome at later follow up (3-months p=0.103; 6-months p=0.285). There were no differences in the degree of resection among the groups.

CONCLUSION

Continuous physical examination has shown to be of value as an additional layer of monitoring of subcortical white matter during resection and combining several methods may help increase the efficacy of mapping and monitoring of subcortical functions.

Computational Identification of Tumor Anatomic Location Associated with Survival in 2 Large Cohorts of Human Primary Glioblastomas

BACKGROUND AND PURPOSE

Tumor location has been shown to be a significant prognostic factor in patients with glioblastoma. The purpose of this study was to characterize glioblastoma lesions by identifying MR imaging voxel-based tumor location features that are associated with tumor molecular profiles, patient characteristics, and clinical outcomes.

MATERIALS AND METHODS

Preoperative T1 anatomic MR images of 384 patients with glioblastomas were obtained from 2 independent cohorts (n = 253 from the Stanford University Medical Center for training and n = 131 from The Cancer Genome Atlas for validation). An automated computational image-analysis pipeline was developed to determine the anatomic locations of tumor in each patient. Voxel-based differences in tumor location between good (overall survival of >17 months) and poor (overall survival of <11 months) survival groups identified in the training cohort were used to classify patients in The Cancer Genome Atlas cohort into 2 brain-location groups, for which clinical features, messenger RNA expression, and copy number changes were compared to elucidate the biologic basis of tumors located in different brain regions.

RESULTS

Tumors in the right occipitotemporal periventricular white matter were significantly associated with poor survival in both training and test cohorts (both, log-rank P < .05) and had larger tumor volume compared with tumors in other locations. Tumors in the right periatrial location were associated with hypoxia pathway enrichment and PDGFRA amplification, making them potential targets for subgroup-specific therapies.

CONCLUSIONS

Voxel-based location in glioblastoma is associated with patient outcome and may have a potential role for guiding personalized treatment.

The value of using a brain laser interstitial thermal therapy (LITT) system in patients presenting with high grade gliomas where maximal safe resection may not be feasible

Background

The objective of this analysis was to determine the value (incremental cost/increment benefit) of a brain LITT system versus employing current surgical options recommended by NCCN guidelines, specifically open resection (i.e. craniotomy) methods or biopsy (collectively termed CURRENT TREATMENTS) in patients where maximal safe resection may not be feasible. As has been demonstrated in the literature, extent of resection/ablation with minimal complications are independently related to overall survival.

Methods

A cost effectiveness analysis from a societal perspective was employed using TreeAge Pro 2014 software. Direct costs (using national average Medicare reimbursement amounts), outcomes (overall survival), and value [defined as increment cost/incremental survival—evaluated as cost/life year gained (LYG)] were evaluated. Sensitivity analysis was also performed to determine which variables had the largest effect on incremental costs and outcomes.

Results

In the base case, the overall survival was improved with brain LITT versus CURRENT TREATMENTS by 3.07 months at an additional cost of $7508 (or $29,340/LYG). This amount was significantly less than the current international threshold value for $32,575/LYG and considerably less than the US threshold value of $50,000/LYG. This incremental cost may also qualify under NICE criteria for end of life therapies. In sensitivity analysis: As percent local recurrence GBM increased; cost of DRG25/26 increased; percent GTR increased; and gliadel use increased—the value of brain LITT improved. Additionally, in those patients where a biopsy is the only option, brain LITT extended life by 7 months.

Conclusions

Brain LITT should be considered a viable option for treatment of high grade gliomas as it improves survival at a cost which appears to be of good value to society. This incremental cost is less than the international and US thresholds for good value.