Widening the Operative Corridor-Evaluating the Transcortical Approach to Giant Falcine Meningiomas

BACKGROUND

Giant falcine meningiomas are surgically complex as they are deep in location, concealed by normal brain parenchyma, in close proximity to various neurovascular structures, and frequently involve the falx bilaterally. Although classically accessed using a bifrontal craniotomy and interhemispheric approach, little data exist on alternative operative corridors for these challenging tumors. We evaluated perioperative and long-term outcomes in patients undergoing transcortical resection of giant bilateral falcine meningiomas.

METHODS

From 2013 to 2022, fourteen patients with giant bilateral falcine meningiomas treated via a transcortical approach at our institution were identified. Perioperative and long-term outcomes were evaluated to determine predictors of adverse events. Corticectomy depth was also analyzed to determine if it correlated with increased postoperative seizure rates.

RESULTS

57.1% of cases were WHO grade 2 meningiomas. Average tumor volume was 77.8 ± 46.5 cm3 and near/gross total resection was achieved in 78.6% of patients. No patient developed a venous infarct or had seizures in the 6 months after surgery. Average corticectomy depth was 0.83 ± 0.71 cm and increasing corticectomy depth did not correlate with higher risk of postoperative seizures (P = 0.44). Increasing extent of tumor resection correlated with lower tumor grade (P = 0.011) and only 1 patient required repeat resection during a median follow-period of 24.9 months.

CONCLUSIONS

The transcortical approach is a safe alternative corridor for accessing giant, falcine meningiomas, and postoperative seizures were not found to correlate with increasing corticectomy depth. Further prospective studies are necessary to determine the best approach to these surgically complex lesions.

The Utility of Transcranial Electrical Stimulation Motor Evoked Potential Monitoring in Predicting Postoperative Supplementary Motor Area Syndrome and Motor Function Recovery

BACKGROUND

Postoperative hemiparesis following frontal lobe lesion resection is alarming, and predicting motor function recovery is challenging. Supplementary motor area (SMA) syndrome following resection of frontal lobe lesions is often indistinguishable from postoperative motor deficit due to surgical injury of motor tracts. We aimed to describe the use of intraoperative transcranial electrical stimulation (TES) with motor evoked potential monitoring data as a diagnostic tool to distinguish between SMA syndrome and permanent motor deficit (PMD).

METHODS

A retrospective analysis of 235 patients undergoing craniotomy and resection with TES-MEP monitoring for a frontal lobe lesion was performed. Patients who developed immediate postoperative motor deficit were included. Motor deficit and TES-MEP findings were categorized by muscle group as left upper extremity, left lower extremity, right upper extremity, or right lower extremity. Statistical analysis was performed to determine the predictive value of stable TES-MEP for SMA syndrome versus PMD.

RESULTS

This study included 20 patients comprising 29 cases of immediate postoperative motor deficit by muscle group. Of these, 27 cases resolved and were diagnosed as SMA syndrome, and 2 cases progressed to PMD. TES-MEP stability was significantly associated with diagnosis of SMA syndrome (P = 0.015). TES-MEP showed excellent diagnostic utility with a sensitivity and positive predictive value of 100% and 92.6%, respectively. Negative predictive value was 100%.

CONCLUSIONS

Temporary SMA syndrome is difficult to distinguish from PMD immediately postoperatively. TES-MEP may be a useful intraoperative adjunct that may aid in distinguishing SMA syndrome from PMD secondary to surgical injury.

The Learning Curve and Clinical Outcomes With 250 Laser Ablations for Brain Tumors: A Pathway to Experience

BACKGROUND AND OBJECTIVES

Laser interstitial thermal therapy (LITT) has gained popularity as a minimally invasive technique for treating brain tumors. Despite its proven safety profile, LITT is not yet widely available, and there is a lack of data on the learning curve required to achieve proficiency. This study analyzes a 250-patient cohort of laser-ablated tumors to describe changes in patient selection and clinical outcomes over time and experience, with the aim of providing insight into the learning curve for incorporating LITT into a neuro-oncology program and identifying a cutoff point that distinguishes novice from expert performance.

METHODS

We retrospectively reviewed 250 patients with brain tumor who underwent LITT between 2013 and 2022. Demographic and clinical data were analyzed. Kaplan Meier curves were used for survival analysis. Operative time was evaluated using exponential curve-fit regression analysis to identify when consistent improvement began.

RESULTS

The patients were divided into quartiles (Q) based on their date of surgery. Mean tumor volume increased over time (Q1 = 5.7 and Q4 = 11.9 cm3, P = .004), and newly diagnosed lesions were more frequently ablated (P = .0001). Mean operative time (Q1 v Q4 = 322.3 v 204.6 min, P < .0001) and neurosurgical readmission rate (Q1 v Q4 = 7.8% v 0%, P = .03) were reduced over time. The exponential curve-fit analysis showed a sustained decay in operative time after case #74. The extent of ablation (P = .69), the recurrence (P = .11), and the postoperative complication rate (P = .78) did not vary over time.

CONCLUSION

After treating 74 patients, a downward trend in the operative time is observed. Patient selection is broadened as experience increases.

Exploring the Landscape of Machine Learning Applications in Neurosurgery: A Bibliometric Analysis and Narrative Review of Trends and Future Directions

BACKGROUND

The field of neurosurgery has consistently represented an area of innovation and integration of technology since its inception. As such, machine learning (ML) has found its way into applications within neurosurgery relatively rapidly. Through this bibliometric review and cluster analysis, we seek to identify trends and emerging applications of ML within neurosurgery.

METHODS

A bibliometric analysis was carried out in the Web of Science database on publications from January 2000 to March 2023. The full data set of the 200 most cited publications including title, author information, journal, citation count, keywords, and abstracts for each publication was evaluated in CiteSpace. CiteSpace was used to elucidate publication characteristics, trends, and topic clusters via collaborate network analysis using the Kamada-Kawai algorithm.

RESULTS

The 25 most cited titles were included in our analysis. Harvard University and its affiliates represented the top institution, contributing nearly 25% of publications in the literature. WORLD NEUROSURGERY was the journal with the highest net citation count of 747 (29%). Collaborative network analysis generated 12 unique clusters, the largest of which was machine learning, followed by feature importance and deep brain stimulation.

CONCLUSION

This review highlights the most impactful articles pertaining to ML in the field of neurosurgery. ML has been applied into several sub-specialties within neurosurgery to optimize patient care, with special attention to outcome predictors, patient selection, and surgical decision making.

Management of Refractory Post-operative Osteomyelitis and Discitis: A Case Report

Vertebral osteomyelitis/discitis is a relatively rare disease but is a known potential complication of spinal surgical intervention. In general, the first-line treatment for this condition is targeted antibiotic therapy with surgical intervention only utilized in refractory cases with evidence of extensive damage, structural instability, or abscess formation. However, surgical best practices have not been established for osteomyelitis, including indications for anterior lateral interbody fusion (ALIF), posterior lateral interbody fusion (PLIF), or direct lateral interbody fusion (DLIF). This case provides a discussion of the indications that led to a direct lateral approach in the setting of refractory osteomyelitis/discitis, supporting factors that led to its success, and the efficacy of utilizing intraoperative neuromonitoring in cases of infection.

Same-day discharge after craniotomy for brain tumor resection: enhancing patient selection through a prognostic scoring system

OBJECTIVE

Neurosurgery, among other surgical fields, is amid a shift in patient management with enhanced recovery and same-day discharge (SDD) protocols slowly becoming more popular and feasible. While such protocols reduce the risk of nosocomial complications and improve patient satisfaction, appropriate patient selection remains an area of debate. The authors aimed to better quantify selection criteria through a prospective follow-up study of patients undergoing brain tumor resection with SDD.

METHODS

Three arms of analysis were carried out. First, clinical data of SDD patients were prospectively collected between August 2021 and August 2022. In parallel, a retrospective analysis of patients who qualified for SDD but were excluded at surgeon clinical discretion over the same period was performed. Third, a comparative analysis of the pilot and follow-up studies was done from which a clinical scoring system for patient selection was derived.

RESULTS

Over the duration of the study, 31 of 334 patients were selected for SDD while 59 qualified for SDD by previously defined criteria but were not selected at the surgeon's discretion. There was no difference in outcomes between the two groups, and there were no postoperative complications among the SDD group within 30 days of surgery. Preoperative clinical characteristics found to be significantly different between the two cohorts (left-sided lesion, extra-axial pathology, prior treatment of brain tumor, and tumor volume ≤ 11.75 cm3) were included in a predictive scoring system for successful SDD. The scoring system was found to significantly predict high or low likelihood for successful SDD when tested on the mixed prospective cohort.

CONCLUSIONS

This study provides a straightforward clinical scoring system for appropriate selection of candidates for SDD after craniotomy for brain tumor resection. This clinical tool aims to aid clinicians in appropriate admission course selection and builds on the growing literature surrounding same-day and outpatient cranial neurosurgery.

Radical supramaximal resection for newly diagnosed left-sided eloquent glioblastoma: safety and improved survival over gross-total resection

OBJECTIVE

Supramaximal resection (SMR) has arisen as a possible surrogate to gross-total resection (GTR) to improve survival in newly diagnosed glioblastoma (nGBM). However, SMR has traditionally been limited to noneloquent regions and its feasibility in eloquent nGBM remains unclear. The authors conducted a retrospective multivariate propensity-matched analysis comparing survival outcomes for patients with left-sided eloquent nGBM undergoing SMR versus GTR.

METHODS

A retrospective review was performed of all patients at our institution who underwent SMR or GTR of a left-sided eloquent nGBM during the period from 2011 to 2020. All patients underwent some form of preoperative or intraoperative functional mapping and underwent awake or asleep craniotomy (craniotomy under general anesthesia); however, awake craniotomy was performed in the majority of patients and the focus of the study was SMR achieved via awake craniotomy and functional mapping with lesionectomy and additional peritumoral fluid attenuated inversion recovery (FLAIR) resection. Propensity scores were generated controlling for age, tumor location, and preoperative Karnofsky Performance Status (KPS) score with the nearest-neighbor algorithm.

RESULTS

A total of 102 patients (48 SMR, 54 GTR) were included in this study. The median overall survival (OS) and progression-free survival (PFS) for patients receiving SMR were 22.9 and 5.1 months, respectively. Propensity matching resulted in a final cohort of 27 SMR versus 27 GTR patients. SMR conferred improved OS (21.55 vs 15.49 months, p = 0.0098) and PFS (4.51 vs 3.59 months, p = 0.041) compared to GTR. There was no significant difference in postoperative complication rates or KPS score in SMR compared with GTR patients (p = 0.236 and p = 0.736, respectively). In patients receiving SMR, improved OS and PFS showed a dose-dependent relationship with extent of FLAIR resection (EOFR) on log-rank test for trend (p < 0.001).

CONCLUSIONS

SMR by means of awake craniotomy with functional mapping for left-sided eloquent nGBM is safe and confers a survival benefit compared to GTR obtained with lesionectomy alone while preserving postoperative neurological integrity. When tolerated, greater EOFR with SMR may be associated with improved survival.

QLTI-13. FEASIBILITY OF SAMEDAY DISCHARGE AFTER BRAIN TUMOR RESECTION: A PROSPECTIVE QUALITY INTERVENTION STUDY

INTRODUCTION

Cranial neurosurgery confers psychological stress, as well as the stress of being in the hospital rather than in one’s preferred surroundings. Compared with inpatient admissions, same-day discharges reduce patient exposure to nosocomial infection, thromboembolic complications, and medical error. Also, it reduces costs to the health care system.

OBJECTIVE

To report the results of a pilot study that prospectively evaluated for the first time in a United States hospital, the outcomes of patients that underwent brain tumor surgery and are discharged home the same day as surgery.

METHODS

A quality intervention study including patients who underwent outpatient craniotomy for brain tumors by a single neurosurgeon (R.J.K) at the University of Miami from August 2020 to August 2021 was performed. Patients included were between 16 to 85 years old, with a Karnofsky Performance Status score of ≥ 70, and with supratentorial tumors with a maximum diameter of 4 cm. Complete demographic and clinical data were collected prospectively for each patient. In all patients, the minimum observation period was 6 h after surgery.

RESULTS

37 of 334 patients met the inclusion criteria for the outpatient protocol. Thirty-two patients were discharged on the same day as surgery. Five patients (14%) were considered eligible for outpatient surgery but were ultimately admitted to the hospital postoperatively and were discharged after overnight observation. No postoperative complications were noted at two-week follow-up.

CONCLUSION

With appropriate selection and postoperative monitoring, same-day discharge can be considered a safe and feasible option for certain craniotomy cases. Establishing a multidisciplinary team of physicians, nurses, radiologists, and physical therapists is critical to achieving this aim. Physicians should have a low threshold to admit a patient with concerning exam findings, complications, or complicated past medical history

Use of virtual magnetic resonance imaging to compensate for brain shift during image-guided surgery: illustrative case

BACKGROUND

Maximal safe resection is the paramount objective in the surgical management of malignant brain tumors. It is facilitated through use of image-guided neuronavigation. Intraoperative image guidance systems use preoperative magnetic resonance imaging (MRI) as the navigational map. The accuracy of neuronavigation is limited by intraoperative brain shift and can become less accurate over the course of the procedure. Intraoperative MRI can compensate for dynamic brain shift but requires significant space and capital investment, often unavailable at many centers.

OBSERVATIONS

The authors described a case in which an image fusion algorithm was used in conjunction with an intraoperative computed tomography (CT) system to compensate for brain shift during resection of a brainstem hemorrhagic melanoma metastasis. Following initial debulking of the hemorrhagic metastasis, intraoperative CT was performed to ascertain extent of resection. An elastic image fusion (EIF) algorithm was used to create virtual MRI relative to both the intraoperative CT scan and preoperative MRI, which facilitated complete resection of the tumor while preserving critical brainstem anatomy.

LESSONS

EIF algorithms can be used with multimodal images (preoperative MRI and intraoperative CT) and create an updated virtual MRI data set to compensate for brain shift in neurosurgery and aid in maximum safe resection of malignant brain tumors.

Systematic Review of Epigenetic Therapies for Treatment of IDH-mutant Glioma

BACKGROUND

Isocitrate dehydrogenase (IDH) mutations are present in 70% of World Health Organization grade II and III gliomas. IDH mutation induces accumulation of the oncometabolite 2-hydroxyglutarate. Therefore, therapies targeting reversal of epigenetic dysregulation in gliomas have been suggested. However, the utility of epigenetic treatments in gliomas remains unclear. Here, we present the first clinical systematic review of epigenetic therapies in treatment of IDH-mutant gliomas and highlight their safety and efficacy.

METHODS

We conducted a systematic search of electronic databases from 2000 to January 2021 following PRISMA guidelines. Articles were screened to include clinical usage of epigenetic therapies in case reports, prospective case series, or clinical trials. Primary and secondary outcomes included safety/tolerability of epigenetic therapies and progression-free survival/overall survival, respectively.

RESULTS

A total of 133 patients across 8 clinical studies were included in our analysis. IDH inhibitors appear to have the best safety profile, with an overall grade 3/grade 4 adverse event rate of 9%. Response rates to IDH-mutant inhibitors were highest in nonenhancing gliomas (stable disease achieved in 55% of patients). In contrast, histone deacetylase inhibitors demonstrate a lower safety profile with single-study adverse events as high as 28%.

CONCLUSION

IDH inhibitors appear promising given their benign toxicity profile and ease of monitoring. Histone deacetylase inhibitors appear to have a narrow therapeutic index, as lower concentrations do not appear effective, while increased doses can produce severe immunosuppressive effects. Preliminary data suggest that epigenetic therapies are generally well tolerated and may control disease in certain patient groups, such as those with nonenhancing lesions.

Same-day discharge after brain tumor resection: a prospective pilot study

Purpose

Outpatient brain surgery has many advantages for the psychological and physical wellbeing of patients, as well as reduced costs to the health care system. Compared with inpatient admissions, same day discharges reduce patient exposure to nosocomial infection, thromboembolic complications, and medical error. We aim to establish a prospectively collected quality outcomes database to examine the outcomes of patients that undergo brain tumor resection and are discharged home the same day as surgery.

Methods

We have established a prospectively collected quality outcomes database to examine the outcomes of all patients that underwent brain tumor resection by a single neurosurgeon (R.J.K) at our institution from August 2020 to August 2021 and were discharged home the same day as surgery.

Results

Over the one-year period this study was conducted, 37 of 334 patients met inclusion criteria for the outpatient protocol. Thirty-two patients were discharged on the same day as surgery. Five patients (14%) were considered eligible for outpatient surgery but were ultimately admitted to the hospital postoperatively and were discharged after an overnight observation. No postoperative complications were noted at two-week postoperative follow-up.

Conclusion

In select patients undergoing brain tumor surgery, same day discharge should be considered. Establishing a multidisciplinary team of physicians, nurses, radiologists, and physical therapists is critical to achieving this aim. Physicians should have a low threshold to admit a patient with concerning exam findings, complications, or complicated past medical history. Once discharged, open communication with the patient and their family is critical to detect complications that should trigger rehospitalization and intervention.

EPID-16. DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR IN PEDIATRIC PATIENTS: A QUANTITATIVE EXPLORATION

BACKGROUND

Diffuse leptomeningeal glioneuronal tumor (DLGNT), also known as oligodendrogliomatosis, is a rare neuro-oncologic condition along the neuraxis that remains poorly understood in children. We sought to describe our institutional experience and quantitively summarize the clinical survival and prognostic features of DLGNT in the pediatric population across the contemporary literature.

METHODS

We report four institutional cases of pediatric DLGNT diagnosed between 2000-2020 based on retrospective review of our records, and performed a comprehensive literature search for published cases from 2000 onwards to create an integrated cohort for analysis. Kaplan-Meier estimations, Fisher’s exact test, and logistic regression were utilized to interrogate the data.

RESULTS

Our overall integrated cohort consisted of 54 pediatric DLGNT patients, with 19 (35%) female and 35 (65%) male patients diagnosed at an average age of 6.4 years (range, 1.3-17 years) by means of surgical biopsy. Chemotherapy was used in 45 cases (83%), and mean follow-up time of 54 months (range, 3-204). Across the entire cohort, overall survival 1 month after diagnosis was 96% (95% CI 86-99%), and by 10 years was 69% (95% CI 49-82%). On multivariate analysis of complete data, chemotherapy treatment (HR=0.23, P=0.04) was statistically predictive of longer overall survival. When including limited data, longer duration of symptoms by presentation (HR=1.03, P=0.03) was statistically predictive of shorter overall survival.

CONCLUSIONS

This is the first quantitative study of pediatric DLGNT clinical course. More than 2-out-of-3 pediatric DLGNT patients survive beyond one decade. Chemotherapy is statistically associated with longer survival in DLGNT pediatric patients and should form the core of any treatment regimen in this setting. Early detection by means of judicious imaging and surgical biopsy for tissue diagnosis can lead to earlier treatment and likely superior outcomes.

A Novel Inhibitor Targeting NLRP3 Inflammasome Reduces Neuropathology and Improves Cognitive Function in Alzheimer's Disease Transgenic Mice

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, and the most common type of dementia. A growing body of evidence has implicated neuroinflammation as an essential player in the etiology of AD. Inflammasomes are intracellular multiprotein complexes and essential components of innate immunity in response to pathogen- and danger-associated molecular patterns. Among the known inflammasomes, the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays a critical role in the pathogenesis of AD.

OBJECTIVE

We recently developed a novel class of small molecule inhibitors that selectively target the NLRP3 inflammasome. One of the lead compounds, JC124, has shown therapeutic efficacy in a transgenic animal model of AD. In this study we tested the preventative efficacy of JC124 in another strain of transgenic AD mice.

METHODS

In this study, 5-month-old female APP/PS1 and matched wild type mice were treated orally with JC124 for 3 months. After completion of treatment, cognitive functions and AD pathologies, as well as protein expression levels of synaptic proteins, were assessed.

RESULTS

We found that inhibition of NLRP3 inflammasome with JC124 significantly decreased multiple AD pathologies in APP/PS1 mice, including amyloid-β (Aβ) load, neuroinflammation, and neuronal cell cycle re-entry, accompanied by preserved synaptic plasticity with higher expression of pre- and post-synaptic proteins, increased hippocampal neurogenesis, and improved cognitive functions.

CONCLUSION

Our study demonstrates the importance of the NLRP3 inflammasome in AD pathological development, and pharmacological inhibition of NLRP3 inflammasome with small molecule inhibitors represents a potential therapy for AD.

Augmented reality head-mounted display-based incision planning in cranial neurosurgery: a prospective pilot study

OBJECTIVE

Monitor and wand-based neuronavigation stations (MWBNSs) for frameless intraoperative neuronavigation are routinely used in cranial neurosurgery. However, they are temporally and spatially cumbersome; the OR must be arranged around the MWBNS, at least one hand must be used to manipulate the MWBNS wand (interrupting a bimanual surgical technique), and the surgical workflow is interrupted as the surgeon stops to "check the navigation" on a remote monitor. Thus, there is need for continuous, real-time, hands-free, neuronavigation solutions. Augmented reality (AR) is poised to streamline these issues. The authors present the first reported prospective pilot study investigating the feasibility of using the OpenSight application with an AR head-mounted display to map out the borders of tumors in patients undergoing elective craniotomy for tumor resection, and to compare the degree of correspondence with MWBNS tracing.

METHODS

Eleven consecutive patients undergoing elective craniotomy for brain tumor resection were prospectively identified and underwent circumferential tumor border tracing at the time of incision planning by a surgeon wearing HoloLens AR glasses running the commercially available OpenSight application registered to the patient and preoperative MRI. Then, the same patient underwent circumferential tumor border tracing using the StealthStation S8 MWBNS. Postoperatively, both tumor border tracings were compared by two blinded board-certified neurosurgeons and rated as having an excellent, adequate, or poor correspondence degree based on a subjective sense of the overlap. Objective overlap area measurements were also determined.

RESULTS

Eleven patients undergoing craniotomy were included in the study. Five patient procedures were rated as having an excellent correspondence degree, 5 had an adequate correspondence degree, and 1 had poor correspondence. Both raters agreed on the rating in all cases. AR tracing was possible in all cases.

CONCLUSIONS

In this small pilot study, the authors found that AR was implementable in the workflow of a neurosurgery OR, and was a feasible method of preoperative tumor border identification for incision planning. Future studies are needed to identify strategies to improve and optimize AR accuracy.

Robotic guidance platform for laser interstitial thermal ablation and stereotactic needle biopsies: a single center experience

While laser ablation has become an increasingly important tool in the neurosurgical oncologist's armamentarium, deep seated lesions, and those located near critical structures require utmost accuracy during stereotactic laser catheter placement. Robotic devices have evolved significantly over the past two decades becoming an accurate and safe tool for stereotactic neurosurgery. Here, we present our single center experience with the MedTech ROSA ONE Brain robot for robotic guidance in laser interstitial thermal therapy (LITT) and stereotactic biopsies. We retrospectively analyzed the first 70 consecutive patients treated with ROSA device at a single academic medical center. Forty-three patients received needle biopsy immediately followed by LITT with the catheter placed with robotic guidance and 27 received stereotactic needle biopsy alone. All the procedures were performed frameless with skull bone fiducials for registration. We report data regarding intraoperative details, mortality and morbidity, diagnostic yield and lesion characteristics on MRI. Also, we describe the surgical workflow for both procedures. The mean age was 60.3 ± 15 years. The diagnostic yield was positive in 98.5% (n = 69). Sixty-three biopsies (90%) were supratentorial and seven (10%) were infratentorial. Gliomas represented 54.3% of the patients (n = 38). There were two postoperative deaths (2.8%). No permanent morbidity related to surgery were observed. We did not find intraoperative technical problems with the device. There was no need to reposition the needle after the initial placement. Stereotactic robotic guided placement of laser ablation catheters and biopsy needles is safe, accurate, and can be implemented into a neurosurgical workflow.

A Cohort Study on Prognostic Factors for Laser Interstitial Thermal Therapy Success in Newly Diagnosed Glioblastoma

BACKGROUND

Laser interstitial thermal therapy (LITT) is a promising approach for cytoreduction of deep-seated gliomas. However, parameters contributing to treatment success remain unclear.

OBJECTIVE

To identify extent of ablation (EOA) and time to chemotherapy (TTC) as predictors of improved overall and progression-free survival (OS, PFS) and suggest laser parameters to achieve optimal EOA.

METHODS

Demographic, clinical, and survival data were collected retrospectively from 20 patients undergoing LITT for newly diagnosed glioblastoma (nGBM). EOA was calculated through magnetic resonance imaging-based volumetric analysis. Kaplan-Meier and multivariate Cox regression were used to examine the relationship between EOA with OS and PFS accounting for covariates (age, isocitrate dehydrogenase-1 (IDH1) mutation, O6-methylguanine-DNA methyltransferase hypermethylation). The effect of laser thermodynamic parameters (power, energy, time) on EOA was identified through linear regression.

RESULTS

Median OS and PFS for the entire cohort were 36.2 and 3.5 mo respectively. Patient's with >70% EOA had significantly improved PFS compared to ≤70% EOA (5.2 vs 2.3 mo, P = .01) and trended toward improved OS (36.2 vs 11 mo, P = .07) on univariate and multivariate analysis. Total laser power was a significant predictor for increased EOA when accounting for preoperative lesion volume (P = .001). Chemotherapy within 16 d of surgery significantly predicted improved PFS compared to delaying chemotherapy (9.4 vs 3.1 mo, P = .009).

CONCLUSION

Increased EOA was a predictor of improved PFS with evidence of a trend toward improved OS in LITT treatment of nGBM. A strategy favoring higher laser power during tumor ablation may achieve optimal EOA. Early transition to chemotherapy after LITT improves PFS.

Multiple Iterations of Magnetic Resonance-Guided Laser Interstitial Thermal Ablation of Brain Metastases: Single Surgeon's Experience and Review of the Literature

BACKGROUND

Prior treatment with magnetic resonance-guided, laser-induced thermal therapy (LITT) is widely assumed not to be a contraindication for further treatment of brain lesions, including further iterations of LITT. However, the safety and efficacy of repeat LITT treatments have never been formally investigated.

OBJECTIVE

To evaluate treatment with multiple iterations of LITT.

METHODS

All patients treated with LITT at least twice at our institution were included in the study. Outcomes and neurological examinations from before and after surgery were retrospectively examined from clinic notes. Perilesonal edema was determined at various timepoints using volumetric data derived from manual tracings of fluid-attenuated inversion recovery (FLAIR) enhancement on magnetic resonance imaging (MRI). Finally, a literature review of prior cases of repeat LITT was performed.

RESULTS

A total of 9 patients underwent 18 treatments with LITT; all but 1 of whom were treated for metastatic brain lesions. One patient had a transient cerebrospinal fluid leak, whereas a second patient had a superficial wound infection, both of which resolved with standard medical care. The remaining 7 patients tolerated all LITT procedures without complication. Analysis of perilesional edema volume demonstrated a correlation with the amount of energy delivered during LITT. Literature review found 5 published papers describing 9 patients who underwent LITT more than once, the majority of whom tolerated repeat LITT well.

CONCLUSION

LITT is a safe and promising treatment modality and may be used multiple times without issue. There appears to be an association between the amount of energy delivered during a LITT session and the degree of postoperative perilesional edema.

Current experimental therapies for atypical and malignant meningiomas

INTRODUCTION

Atypical (WHO grade II) and malignant meningiomas (WHO Grade III) are a rare subset of primary intracranial tumors. Given their relatively high recurrence rate after surgical resection and radiotherapy, there has been a recent push to explore other adjuvant treatment options for these treatment-refractory tumors. Recent advances in molecular sequencing of tumors have elucidated new pathways and drug targets which are currently being studied. This article provides a thorough overview of novel investigational therapeutics including targeted therapy, immunotherapy, and new technological modalities for atypical and malignant meningiomas.

METHODS

We performed a comprehensive review of the available literature regarding preclinical and clinical evidence for emerging treatments for high grade meningiomas from 1980 to 2020 including contemporaneous clinical trials.

RESULTS

There is encouraging preclinical evidence regarding the efficacy of the emerging treatments discussed in this article. Several clinical trials are currently recruiting patients to translate targeted molecular therapy for meningiomas. Several clinical studies have suggested a clinical benefit of combinatorial treatment for these treatment-refractory tumors.

CONCLUSION

With numerous active clinical trials for high grade meningiomas, a meaningful improvement in the outcomes for these tumors may be on the horizon.

Age of diagnosis clinically differentiates atypical teratoid/rhabdoid tumors diagnosed below age of 3 years: a database study

BACKGROUND

Atypical teratoid/rhabdoid tumor (ATRT) is a rare and largely pediatric diagnosis, with poor survival. Diagnosis below the age of 3 years is characteristically seen as a poor prognostic sign. However, elucidating if clinical differences exist within this niche age group has never been attempted before. Correspondingly, we sought to characterize clinical profile of ATRT diagnoses before the age of 3 years based on separate ages of diagnosis.

METHODS

All pediatric ATRT patients aged < 3 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Age groups were divided based on diagnoses at ages 0-1 years in group 1, 1-2 years in group 2, and 2-3 years in group 3. Data were summarized, and overall survival (OS) was modeled using Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 354 ATRT diagnoses were made before the age of 3 years, with surgery used in 316 (89%) cases, chemotherapy in 242 (68%) cases, and radiation therapy in 118 (33%) cases. In terms of diagnosis age, there were 153 (43%) in group 1, 137 (39%) in group 2, and 64 (18%) in group 3. With respect to OS, median value was 9.9 months in group 1, 28.4 months in group 2, and 15.9 months in group 3. Upon multivariate analysis, receiving radiation therapy was the only parameter shared amongst all three groups as independently prognostic of longer OS (HR 0.53, P = 0.01 in group 1; HR 0.34, P < 0.01 in group 2; HR 0.31, P < 0.01 in group 3). In group 1, surgery (HR 0.47, P < 0.01) and chemotherapy (HR 0.44, P < 0.01) were also independently prognostic of longer OS. In group 3, multiple socioeconomic parameters were identified to independently predict longer OS. There were no additional predictive parameters identified in group 2.

CONCLUSION

Although ATRT diagnosed before the age of 3 is typically viewed a poor prognostic age category, our findings demonstrate that the clinical profile of this pediatric niche is highly heterogeneous based on age of diagnosis. Survival of only those diagnosed between 0 and 1 years is independently prognosticated by all three treatment modalities; patients diagnosed between 1 and 2 years trend towards longest survival, and socioeconomic parameters are most influential in those diagnosed between 2 and 3 years.

Stimulated Raman Histology for Rapid Intraoperative Diagnosis of Gliomas

BACKGROUND

Intraoperative pathologic diagnosis traditionally involves frozen section histopathology, which may be labor and time intensive. Indeed, a technique that streamlines the acquisition and evaluation of intraoperative histologic data may expedite surgical decision-making and shorten operative time. Stimulated Raman histology (SRH) is an emerging technology that allows for more rapid acquisition and interpretation of intraoperative histopathologic data.

METHODS

A blinded, prospective cohort study was performed for 82 patients undergoing resection for a central nervous system tumor. Of these, 21 patients were diagnosed with glioma either intraoperatively or postoperatively on permanent section histology and included in this study. Time to diagnosis (TTD) and diagnostic accuracy relative to permanent section (the gold standard) were compared between SRH-based diagnosis and conventional frozen section histology. Diagnostic concordance with permanent section was also compared between frozen histopathology and SRH diagnosis.

RESULTS

Diagnostic accuracy was not significantly different between methods (P = 1.00). Diagnostic concordance was not significantly different between methods when comparing 95% confidence intervals for kappa values (κ = 0.215; κ = 0.297; κ = 0.369). Lastly, mean TTD was significantly shorter with SRH-based diagnosis compared with frozen section (43 vs. 9.7 minutes, P < 0.0001). SRH was able to identify key features associated with varying glioma types.

CONCLUSIONS

SRH allows for rapid intraoperative diagnosis without sacrificing diagnostic accuracy. SRH may serve as a promising adjuvant to conventional histopathology to expedite intraoperative pathology consultation and surgical decision-making.

Rapid Intraoperative Diagnosis of Meningiomas using Stimulated Raman Histology

BACKGROUND

Frozen section is a time- and labor-intensive method for intraoperative pathologic diagnosis. As a result, there exists a need to expedite and streamline the acquisition and interpretation of diagnostic histologic data to inform surgical decision making. Stimulated Raman histology (SRH) is an emerging technology that may serve to expedite the acquisition and interpretation of histologic data in the operating room.

METHODS

A blinded, prospective cohort study of 82 patients undergoing resection for tumors of the central nervous system was performed. Twenty-six patients with diagnoses of meningioma on SRH, frozen, or permanent section were included in this subanalysis. Diagnostic time and accuracy of stimulated SRH histology images were compared with the gold standard (frozen section). Agreement of SRH and frozen section diagnosis with permanent section (true) diagnosis was also compared.

RESULTS

Mean time-to-diagnosis was significantly shorter for SRH-mediated diagnosis compared with frozen section (9.2 vs. 35.8, P < 0.0001). Diagnostic accuracy was not significantly different between methods (P = 0.15). Diagnostic agreement was not significantly different between SRH versus frozen, SRH versus permanent, or frozen versus permanent section methods (P = 0.5, P = 0.5, P = 1.00).

CONCLUSIONS

SRH is a promising adjuvant technology that may expedite intraoperative neuropathologic consult without sacrificing diagnostic accuracy.

Sarcoidosis-Lymphoma Syndrome Presenting As Bony Vertebral Metastasis: A Case Report and Literature Review

Sarcoidosis preceding a diagnosis of lymphoma has been a reported phenomenon termed sarcoidosis-lymphoma syndrome. Skeletal metastasis is extremely rare. Here, we detail a case of sarcoidosis-lymphoma syndrome presenting as a lumbar vertebral metastasis with suspected associated intracranial lesions. A 72-year-old man with a history of follicular lymphoma presented with symptomatic central nervous system (CNS) lesions with concurrent lumbar vertebral metastases visualized with CT and MRI. Rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (R-CHOP) with dexamethasone treatment resulted in significant radiographic regression of his intracranial lesions with dramatic symptomatic improvement. Out of concern for compression fracture of his lytic lumbar lesions, kyphoplasty with biopsy was performed showing lymphocytes that were positive for cluster-of-differentiation 10 (CD10), CD20, and B-cell lymphoma 2 (Bcl2). The patient was diagnosed with CNS and vertebral sarcoidosis-lymphoma syndrome and began treatment with high-dose methotrexate. Including the present case, only four occurrences of sarcoidosis-lymphoma syndrome with bony involvement have been described. We detail our own experience and summarize all previous literature. While rare, sarcoidosis-lymphoma may present with CNS and lytic bone involvement; in these cases, symptomatic severity, as well as an effective response to steroid treatment, underscore the importance of an accurate and prompt diagnosis.

The Effects of Leaf Extracts of Four Tree Species on Amygdalus pedunculata Seedlings Growth

Vegetation reconstruction is an urgent problem in fragile environment like coal mine subsidence areas. Amygdalus pedunculata is an important eco-economic shrub species that promotes wind prevention, sand fixation as well as soil and water conservation. The natural regeneration of pure Amygdalus pedunculata forests is difficult to achieve because of its low seed germination rate and weak seedling growth. A stereo-complex ecosystem could potentially promote the germination and seedling growth of A. pedunculata and establish a steady mixed plantation consisting of trees and shrubs. Here, laboratory and pot experiments were conducted to assess the effect of four tree species on morphological and physiological indexes of A. pedunculata. The laboratory experiment showed that A. pedunculata seed germination and seedling growth from Yuyang County (YC-1) and Shenmu County (SC-6) were higher when plants were treated with the aqueous leaf extracts of Pinus sylvestris, Broussonetia papyrifera, and Pinus tabulaeformis compared with Populus simonii at concentrations of 2.5% (E2.5) and 5% (E5). Furthermore, the donor leaf extract was more sensitive to YC-1 than to SC-6. The pot experiment showed that the E2.5 and E5 treatments with the aqueous leaf extracts on the three tree species had strong promoting effects of seedling length, root length, seedling fresh weight, root fresh weight, and ground diameter for YC-1. The activity of catalase of A. pedunculata seedlings first increased and then decreased, while the activity of peroxidase, superoxide dismutase, roots, and the contents of soluble protein and chlorophyll decreased; the opposite patterns were observed for malondialdehyde, soluble sugar, cell membrane permeability, and proline were the opposite. Synthetical allelopathic effect index values of the leaf extracts of the three species on YC-1 were as follows: P. sylvestris > B. papyrifera > P. tabulaeformis (E2.5 to E20). Therefore, P. sylvestris and B. papyrifera could be used to promote the growth of A. pedunculata seedlings as well as for the construction of mixed plantations in coal mine degradation areas. Generally, this study provides new insight into the creation of stereo-complex ecosystems (P. sylvestris + A. pedunculata and B. papyrifera + A. pedunculata) in arid fragile environment.

Telemedicine in Neurosurgery: Lessons Learned from a Systematic Review of the Literature for the COVID-19 Era and Beyond

BACKGROUND

Evolving requirements for patient and physician safety and rapid regulatory changes have stimulated interest in neurosurgical telemedicine in the COVID-19 era.

OBJECTIVE

To conduct a systematic literature review investigating treatment of neurosurgical patients via telemedicine, and to evaluate barriers and challenges. Additionally, we review recent regulatory changes that affect telemedicine in neurosurgery, and our institution's initial experience.

METHODS

A systematic review was performed including all studies investigating success regarding treatment of neurosurgical patients via telemedicine. We reviewed our department's outpatient clinic billing records after telemedicine was implemented from 3/23/2020 to 4/6/2020 and reviewed modifier 95 inclusion to determine the number of face-to-face and telemedicine visits, as well as breakdown of weekly telemedicine clinic visits by subspecialty.

RESULTS

A total of 52 studies (25 prospective and 27 retrospective) with 45 801 patients were analyzed. A total of 13 studies were conducted in the United States and 39 in foreign countries. Patient management was successful via telemedicine in 99.6% of cases. Telemedicine visits failed in 162 cases, 81.5% of which were due to technology failure, and 18.5% of which were due to patients requiring further face-to-face evaluation or treatment. A total of 16 studies compared telemedicine encounters to alternative patient encounter mediums; telemedicine was equivalent or superior in 15 studies. From 3/23/2020 to 4/6/2020, our department had 122 telemedicine visits (65.9%) and 63 face-to-face visits (34.1%). About 94.3% of telemedicine visits were billed using face-to-face procedural codes.

CONCLUSION

Neurosurgical telemedicine encounters appear promising in resource-scarce times, such as during global pandemics.

Remote Cerebellar Hemorrhage Associated With Intra-Operative Cerebrospinal Fluid Leak: A Report of Two Rare Case Presentations and Review of the Literature

Remote cerebellar hemorrhage (RCH) is a rare complication following cranial or spinal neurosurgical procedures. Traditionally, RCH has been associated with frontal or frontotemporal craniotomy with supine patient positioning. Though the exact etiology is unknown, theories have described patient positioning and excessive cerebrospinal fluid (CSF) drainage intra-operatively as contributing factors to cerebellar displacement (cerebellar sag), obstruction of venous flow, and pathogenesis of RCH. 

We report two cases of RCH following a prone, suboccipital craniotomy-C1 laminectomy and a temporal burr hole evacuation of a subdural hygroma. In each case, a large volume of CSF was rapidly evacuated intra-operatively. To the best of our knowledge, both instances represent relatively rare settings for RCH. Additionally, we conducted a comprehensive literature review of PubMed, EMBASE, and Web of Science for all cases of RCH in which peri-operative CSF leakage was explicitly detailed.

Although RCH is thought to be a rare complication of frontotemporal and frontal craniotomies, this case report signifies that RCH may occur in the setting of sub-occipital craniotomy or even after minimally invasive burr hole procedures. For these procedures, careful symptomatic monitoring and follow-up imaging remain essential in diagnosis. Controlled CSF drainage may be useful in mediating dramatic alterations in intracranial pressure (ICP) and cerebellar sag contributing to RCH.

Multiple myeloma presenting as an intramedullary spinal cord tumor: a case report and review of the literature

Background

Extramedullary disease in multiple myeloma often portends a worse diagnosis. In approximately 1% of cases, multiple myeloma may metastasize to the central nervous system as either leptomeningeal involvement or an intracranial, intraparenchymal lesion. Spinal cord metastases, however, are exceedingly rare. We present a case of spinal cord multiple myeloma as well as a literature review of reported cases.

Case presentation

A 66-year-old African American man with multiple myeloma presented with acute midthoracic pain and lower extremity paresis and paresthesia. Magnetic resonance imaging of the spine revealed two contrast-enhancing intramedullary enhancing lesions in the T1–T2 and T6–T7 cord. Resection with biopsy yielded a diagnosis of metastatic multiple myeloma.

Conclusion

To date, only six cases of extramedullary disease to the spinal cord in patients with multiple myeloma have been reported, including our patient’s case. In all cases, neurologic deficit was observed at presentation, and magnetic resonance imaging of the spine revealed an intramedullary, homogeneously enhancing lesion. Current evidence suggests worse prognosis in patients with extramedullary disease to the central nervous system, and treatment paradigms remain debatable.

Building a Brain Tumor Practice: Objective Analysis of Referral Patterns and Implications for the Growth of a Subspecialty Surgical Program

Introduction Growth of surgical caseload among specialties with a large contribution margin is an important financial objective for hospitals. In this study, we examined the diversity of referral patterns to a neurosurgeon over an eight-year interval and examined practice attributes related to surgical growth. Methods The electronic records of all patients undergoing an intracranial surgical procedure between August 2011 and August 2019 by an academic neurosurgeon were reviewed retrospectively. The Herfindahl-Hirschman index (HHI) was used to assess the distribution of referrals among community physicians who referred such patients; a value of HHI <0.15 indicates diversity. The yearly HHI trend was evaluated using meta-regression. Results The neurosurgeon's brain surgery caseload progressively increased on an annual basis from 1.4 to 12.5 cases per week between 2012 and 2018. Among the 1540 cases referred by 1775 different physicians, 78% were from three counties in southeast Florida and 8.1% from two counties in southwest Florida. The HHI declined between 2013 and 2018 by 0.023 per year (0.0046 standard error [SE], p = 0.0073) with the estimated value 0.0063 (0.0014 SE) < 0.15 in 2018 (p < 0.0001). The findings indicate that the base of referring physicians was highly diverse and that growth in caseload was accompanied by significantly less concentration of referrals. Conclusion Surgical growth in the neurosurgeon's practice resulted from a small number of referrals from many physicians, not from many referrals from a small number of physicians. Few physicians referred a sufficient number of patients to warrant attribution of the referral itself to personal knowledge of their patients' eventual outcomes. Rather, factors promoting timely access to patient care appear to have been the driving force for growth.

Primary Low-Grade Astrocytoma of the Spine With Secondary Cerebral Metastasis: A Case Report and Comprehensive Review of the Literature

An astrocytoma is a subclassification of glioma, with primary spinal manifestations accounting for less than 10% of all spinal cord tumors, with the majority encompassing low-grade features. It is even more uncommon for such lesions to demonstrate intracerebral metastasis. We report such an occurrence in a 39-year-old female who initially presented with an intramedullary and intradural mass from T10-L1, as well as secondary metastasis to the mesial right temporal lobe and cerebellum upon clinical follow-up. Surgical resection of the spine and subsequent temporal lobe biopsy confirmed high-grade glioma. Given the rarity and poor prognosis of spinal gliomas with cerebral metastasis, we also summarize all previously reported cases to date. We recommend that physicians maintain an index of suspicion for spinal gliomas in young patients with cord compression related symptoms outside the event of traumatic injury.

Survival benefit of lobectomy for glioblastoma: moving towards radical supramaximal resection

PURPOSE

Extent of resection remains a paramount prognostic factor for long-term outcomes for glioblastoma. As such, supramaximal resection or anatomic lobectomy have been offered for non-eloquent glioblastoma in an attempt to improve overall survival. Here, we conduct a propensity-matched analysis of patients with non-eloquent glioblastoma who underwent either lobectomy or gross total resection of lesion to investigate the efficacy of supramaximal resection of glioblastoma.

METHODS

Patients who underwent initial surgery for gross total resection or lobectomy for non-eloquent glioblastoma at our tertiary care referral center from 2010 to 2019 were included for this propensity-matched survival analysis. Propensity scores were generated with the following covariates: age, location, preoperative KPS, product of perpendicular maximal tumor diameters, and product of perpendicular FLAIR signal diameters. Inverse probability of treatment weighting (IPTW) with generated propensity scores was used to compare progression-free survival and overall survival.

RESULTS

Sixty-nine patients were identified who underwent initial resection of glioblastoma for non-eloquent glioblastoma from 2010 to 2019 (GTR = 37, lobectomy = 32). Using IPTW, overall survival (30.7 vs. 14.1 months) and progression-free survival (17.2 vs. 8.1 months were significantly higher in the lobectomy cohort compared to the GTR group (p < 0.001). There was no significant difference in pre-op or post-op KPS or complication rates between the two groups.

CONCLUSION

Our propensity-matched study suggests that lobectomy for non-eloquent glioblastoma confers an added survival benefit compared to GTR alone. For patients with non-eloquent glioblastoma, a supramaximal resection by means of an anatomic lobectomy should be considered as a primary surgical treatment in select patients if feasible.

Minimally invasive resection of intracranial lesions using tubular retractors: a large, multi-surgeon, multi-institutional series

PURPOSE

Lesions located in subcortical areas are difficult to safely access. Tubular retractors have been increasingly used successfully with low complication profile to access lesions by minimizing brain retraction trauma and distributing pressure radially. Both binocular operative microscope and monocular exoscope are utilized for lesion visualization through tubular retractors. We present the largest multi-surgeon, multi-institutional series to determine the efficacy and safety profile of a transcortical-transtubular approach for intracranial lesion resections with both microscopic and exoscopic visualization.

METHODS

We reviewed a multi-surgeon, multi-institutional case series including transcortical-transtubular resection of intracranial lesions using either BrainPath (NICO, Indianapolis, Indiana) or ViewSite Brain Access System (VBAS, Vycor Medical, Boca Raton, Florida) tubular retractors (n = 113).

RESULTS

One hundred thirteen transtubular resections for intracranial lesions were performed. Patients presented with a diverse number of pathologies including 25 cavernous hemangiomas (21.2%), 15 colloid cysts (13.3%), 26 GBM (23.0%), two meningiomas (1.8%), 27 metastases (23.9%), 9 gliomas (7.9%) and 9 other lesions (7.9%). Mean lesion depth below the cortical surface was 4.4 cm, and mean lesion size was 2.7 cm. A gross total resection was achieved in 81 (71.7%) cases. Permanent complication rate was 4.4%. One patient (0.8%) experienced one early postoperative seizure (< 1 week postop). No patients experienced late seizures (> 1 week follow-up). Mean post-operative hospitalization length was 4.1 days.

CONCLUSION

Tubular retractors provide a minimally invasive operative corridor for resection of intracranial lesions. They provide an effective tool in the neurosurgical armamentarium to resect subcortical lesions with a low complication profile.

Resection versus biopsy in the treatment of multifocal glioblastoma: a weighted survival analysis

OBJECT

Diffuse tumor invasion in multifocal/multicentric GBM (mGBM) often foreshadows poor survival outcome. The correlation between extent of resection in gliomas and patient outcome is well described. The objective of this study was to assess the effect of gross total resection compared to biopsy for mGBM on patient overall survival and progression free survival.

METHODS

Thirty-four patients with mGBM received either biopsy or resection of their largest enhancing lesion from 2011 to 2019. Relevant demographic, peri-operative, and radiographic data were collected. Tumor burden and extent of resection was assessed through measurement of pre-operative and post-operative contrast-enhancing volume. An adjusted Kaplan-Meier survival analysis was conducted using inverse probability of treatment weighting (IPTW) to account for the covariates of age, number of lesions, satellite tumor volume, total pre-operative tumor volume, degree of spread, and location.

RESULTS

Thirty-four patients were identified with sixteen (47.1%) and eighteen (52.9%) patients receiving resection and biopsy respectively. Patients receiving resection exhibited greater median overall survival but not progression free survival compared to biopsy on IPTW analysis (p = 0.026, p = 0.411). Greater than or equal to 85% extent of resection was significantly associated with increased median overall survival (p = 0.016).

CONCLUSION

Overall, our study suggests that resection of the largest contrast-enhancing lesion may provide a survival benefit. Our volumetric analysis suggests that a greater degree of resection results in improved survival. Employing IPTW analysis, we sought to control for selection bias in our retrospective analysis. Thus, aggressive surgical treatment of mGBM may offer improved outcomes. Further clinical trials are needed.

Human neural stem cell transplant location-dependent neuroprotection and motor deficit amelioration in rats with penetrating traumatic brain injury

BACKGROUND

Penetrating traumatic brain injury induces chronic inflammation that drives persistent tissue loss long after injury. Absence of endogenous reparative neurogenesis and effective neuroprotective therapies render injury-induced disability an unmet need. Cell replacement via neural stem cell transplantation could potentially rebuild the tissue and alleviate penetrating traumatic brain injury disability. The optimal transplant location remains to be determined.

METHODS

To test if subacute human neural stem cell (hNSC) transplant location influences engraftment, lesion expansion, and motor deficits, rats (n = 10/group) were randomized to the following four groups (uninjured and three injured): group 1 (Gr1), uninjured with cell transplants (sham+hNSCs), 1-week postunilateral penetrating traumatic brain injury, after establishing motor deficit; group 2 (Gr2), treated with vehicle (media, no cells); group 3 (Gr3), hNSCs transplanted into lesion core (intra); and group 4 (Gr4), hNSCs transplanted into tissue surrounding the lesion (peri). All animals were immunosuppressed for 12 weeks and euthanized following motor assessment.

RESULTS

In Gr2, penetrating traumatic brain injury effect manifests as porencephalic cyst, 22.53 ± 2.87 (% of intact hemisphere), with p value of <0.0001 compared with uninjured Gr1. Group 3 lesion volume at 17.44 ± 2.11 did not differ significantly from Gr2 (p = 0.36), while Gr4 value, 9.17 ± 1.53, differed significantly (p = 0.0001). Engraftment and neuronal differentiation were significantly lower in the uninjured Gr1 (p < 0.05), compared with injured groups. However, there were no differences between Gr3 and Gr4. Significant increase in cortical tissue sparing (p = 0.03), including motor cortex (p = 0.005) was observed in Gr4 but not Gr3. Presence of transplant within lesion or in penumbra attenuated motor deficit development (p < 0.05) compared with Gr2.

CONCLUSION

In aggregate, injury milieu supports transplanted cell proliferation and differentiation independent of location. Unexpectedly, cortical sparing is transplant location dependent. Thus, apart from cell replacement and transplant mediated deficit amelioration, transplant location-dependent neuroprotection may be key to delaying onset or preventing development of injury-induced disability.

LEVEL OF EVIDENCE

Preclinical study evaluation of therapeutic intervention, level VI.

Incidence of high grade gliomas presenting as radiographically non-enhancing lesions: experience in 111 surgically treated non-enhancing gliomas with tissue diagnosis

PURPOSE

Although non-enhancing lesions suspicious for glioma are usually assumed to be low grade glioma (LGG), some high grade glioma (HGG) do not enhance, which may lead to a delay in biopsy and/or resection, diagnosis, and treatment initiation. Thus, there is a clear need for a large-sample study that quantifies the rate of malignant, non-enhancing gliomas.

METHODS

We retrospectively reviewed our series of 561 consecutive surgically treated gliomas with tissue diagnosis, 111 of which were non-enhancing, to determine the prevalence of high-grade histology in radiographically presumed LGG. Relative expression of tumor markers were also reported for non-enhancing lesions to investigate genetic correlates.

RESULTS

We identified 561 surgically treated gliomas with tissue diagnosis from August 2012 to July 2018 and found that 111 patients (19.8%) demonstrated non-enhancing lesions suspicious for glioma on preoperative MRI. Thirty-one (27.9%) of the non-enhancing lesions were classified as HGGs (WHO Grade III or IV). Non-enhancing lesions were four times more likely to be HGG in patients older than 60 years than patients younger than 35 years (41.2% vs. 11.4%, Pearson Chi² p < 0.001). Binomial logistic regression showed a significant inverse effect of age on the presence of IDH mutation in non-enhancing HGGs (p = 0.007).

CONCLUSION

A clinically significant proportion (27.9%) of non-enhancing lesions were found to be HGG on final pathologic diagnosis. Thus, in patients with good functional and health status, especially those older than 60 years, we recommend obtaining tissue diagnosis of all lesions suspected to be glioma, even those that are non-enhancing, to guide diagnosis as well as early initiation of chemotherapy and radiation therapy.

Stimulated Raman histology for rapid and accurate intraoperative diagnosis of CNS tumors: prospective blinded study

OBJECTIVE

In some centers where brain tumor surgery is performed, the opportunity for expert intraoperative neuropathology consultation is lacking. Consequently, surgeons may not have access to the highest quality diagnostic histological data to inform surgical decision-making. Stimulated Raman histology (SRH) is a novel technology that allows for rapid acquisition of diagnostic histological images at the bedside.

METHODS

The authors performed a prospective blinded cohort study of 82 consecutive patients undergoing resection of CNS tumors to compare diagnostic time and accuracy of SRH simulation to the gold standard, i.e., frozen and permanent section diagnosis. Diagnostic accuracy was determined by concordance of SRH-simulated intraoperative pathology consultation with a blinded board-certified neuropathologist, with official frozen section and permanent section results.

RESULTS

Overall, the mean time to diagnosis was 30.5 ± 13.2 minutes faster (p < 0.0001) for SRH simulation than for frozen section, with similar diagnostic correlation: 91.5% (κ = 0.834, p < 0.0001) between SRH simulation and permanent section, and 91.5% between frozen and permanent section (κ = 0.894, p < 0.0001).

CONCLUSIONS

SRH-simulated intraoperative pathology consultation was significantly faster and equally accurate as frozen section.

Network connectivity separate from the hypothesized irritative zone correlates with impaired cognition and higher rates of seizure recurrence

INTRODUCTION

Surgery remains an essential option for the treatment of medically intractable temporal lobe epilepsy (TLE). However, only 66% of patients achieve postoperative seizure freedom, perhaps attributable to an incomplete understanding of brain network alterations in surgical candidates. Here, we applied a novel network modeling algorithm and measured key characteristics of epileptic networks correlated with surgical outcomes and objective measures of cognition.

METHODS

Twenty-two patients were prospectively included, and relevant demographic information was attained. Resting state functional magnetic resonance imaging (rsfMRI) and electroencephalography (EEG) data were recorded and preprocessed. Using our novel algorithm, patient-specific epileptic networks were mapped preoperatively, and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Neuropsychological pre- and postsurgical raw and standardized scores obtained blinded to epileptic network status. Key demographic data and features of epileptic networks were then correlated with surgical outcome using Pearson's product-moment correlation.

RESULTS

At an average follow-up of 18.4 months, 15/22 (68%) patients were seizure-free. Connectivity was measured globally using a functional 3D atlas. Higher mean global connectivity correlated with worse scores in preoperative neuropsychological testing of executive functioning (Ruff Figural Fluency Test [RFFT]-ER; R = 0.943, p = 0.005). A higher ratio of highly correlated connections between regions of interest (ROIs) in the hemisphere contralateral to the seizure onset correlated with impairment in executive functioning (RFFT-ER; R = 0.943, p = 0.005). Higher numbers of highly correlated connections between ROIs in the contralateral hemisphere correlated with impairment in both short- and long-term measures of verbal memory (Rey Auditory Verbal Learning Test Trials 6, 7 [RAVLT6, RAVLT7]; R = -0.650, p = 0.020, R = -0.676, p = 0.030). Epilepsy networks were modeled in each patient, and localization of the epilepsy network in the bitemporal lobes correlated with lower scores in neuropsychological tests measuring verbal learning and short-term memory (RAVLT6; R = -0.671, p = 0.024). Higher rates of seizure recurrence correlated with localization of the epilepsy network bitemporally (R = -0.542, p = 0.014), with the stronger correlation found with localization to the contralateral temporal lobe from side of surgery (R = - 0.530, p = 0.016).

CONCLUSION

Increased connectivity contralateral to seizure onset and epilepsy network spread in the bitemporal lobes correlated with lower measures of executive functioning and verbal memory. Epilepsy network localization to the bitemporal lobes, in particular, the contralateral temporal lobe, is associated with higher rates of seizure recurrence. These findings may reflect network-level disruption that has infiltrated the contralateral hemisphere and the bitemporal lobes contributing to impaired cognition and relatively worse surgical outcomes. Further identification of network parameters that predict patient outcomes may aid in patient selection, resection planning, and ultimately the efficacy of epilepsy surgery.

Use of Tubular Retractors for Minimally Invasive Resection of Deep-Seated Cavernomas

BACKGROUND

Cavernomas located in subcortical or eloquent locations are difficult lesions to access safely. Tubular retractors, which distribute retraction pressure radially, have been increasingly employed successfully. These retractors may be beneficial in subcortical cavernoma resection.

OBJECTIVE

To review a single institution's case series to determine the safety profile and efficacy of transcortical-transtubular cavernoma resections and to describe our transtubular operative technique.

METHODS

We reviewed a single institution's transcortical-transtubular cavernoma resections using either BrainPath (NICO, Indianapolis, Indiana) or ViewSite Brain Access System (Vycor Medical, Boca Raton, Florida) tubular retractors performed from 2013 to 2018 (n = 20).

RESULTS

Gross total resection was achieved in all patients. When a developmental venous anomaly (DVA) was present, avoidance of DVA resection was achieved in all cases (n = 4). All patients had a supratentorial cavernoma with mean depth below cortical surface of 44.1 mm. Average postoperative clinical follow-up was 20.4 wk. Early neurologic deficit rate was 10% (n = 2); permanent neurologic deficit rate was 0%. One patient (5%) experienced early postoperative seizures (&lt; 1 wk postop). No patients experienced late seizures (&gt; 1 wk follow-up). Engel class 1 seizure control at final clinical follow-up was achieved in 87.5% of patients presenting with preoperative epilepsy.

CONCLUSION

Tubular retractors provide a low-profile, minimally invasive operative corridor for resection of subcortical cavernomas. There were no permanent neurologic complications in our series of 20 cases, and long-term seizure control was achieved in all patients. Thus, tubular retractors appear to be a safe and efficacious tool for resection of subcortical cavernomas.

Case Series: A Minimally Invasive Tunneling Approach for Cubital Tunnel Syndrome

Background

Cubital tunnel syndrome (CuTS) is the second most common peripheral neuropathy in the United States. All three current surgical treatment approaches, consisting of in situ decompression, medial epicondylectomy, and transposition, require large curvilinear incisions and dissections that cross the medial epicondyle. However, the use of a large curvilinear incision may not be necessary for in situ decompression and may be achieved with small incisions proximal and distal to the medial epicondyle. This may limit the risk of peri-incisional pain and numbness, similar to the benefits provided by endoscopy.

Objective

The aim of this study is to evaluate a minimally invasive tunneling approach for in situ ulnar nerve decompression utilizing 2 cm incisions proximal and distal to the medial epicondyle.

Methods

A retrospective chart review was performed for patients at Emory University Hospital with CuTS who underwent minimally invasive tunneling for in situ decompression. Seven cases were identified. Patient demographics and data on post-operative complications were collected. Pre-operative severity was graded as a Modified McGowan severity. The primary outcome was evaluated using the post-surgical Messina Criterion. Secondary outcomes were reports of peri-incisional pain or numbness evaluated at follow-up. Descriptive statistics are presented.

Results

Pre-operatively, one of the seven cases was Grade I McGowan and the remaining six were Grade 2a or 2b. Post-operatively, on the Messina Criterion, four of seven patients were rated as having “Good” outcomes, two of seven had “Fair”, while one of seven had “Poor.” There was one post-operative surgical site infection. Among the other six cases, there were no reports of peri-incisional pain or numbness.

Conclusions

The use of less-invasive tunneling approach to in situ decompression yielded positive outcomes in this case series with no reports of peri-incisional pain or numbness. A prospective trial may be useful to explore the theoretical benefits of this novel tunneling approach.

A novel small molecular NLRP3 inflammasome inhibitor alleviates neuroinflammatory response following traumatic brain injury

Background

Neuroinflammation is an essential player in many neurological diseases including traumatic brain injury (TBI). Recent studies have identified that inflammasome complexes are responsible for inflammatory responses in many pathological conditions. Inflammasomes are intracellular multiprotein complexes which regulate the innate immune response, activation of caspase-1, production of pro-inflammatory cytokines IL-1β and IL-18, and induction of cell death (pyroptosis). Among inflammasome family members, the nucleotide-binding domain leucine-rich repeats family protein 3 (NLRP3) is the most extensively studied and its activation is induced following TBI. As a novel target, drug development targeting the formation and activation of NLRP3 inflammasome is a prospective therapy for TBI. We have recently developed a small molecule JC124 with specificity on NLRP3 inflammasome. In this study, we explored the therapeutic value of JC124 for TBI treatment.

Methods

Adult male Sprague-Dawley rats were subjected to a moderate cortical impact injury. Following TBI, animals received 4 doses of JC124 treatment with the first dose starting at 30 min, the second dose at 6 h after TBI, the third and fourth doses at 24 or 30 h following TBI, respectively. Animals were sacrificed at 2 days post-injury. Brain tissues were processed either for ELISA and western blotting analysis for inflammatory response, or for histological examination to assess degenerative neurons, acute inflammatory cell response and lesion volume.

Results

We found that post-injury treatment with JC124 significantly decreased the number of injury-induced degenerating neurons, inflammatory cell response in the injured brain, and cortical lesion volume. Injured animals treated with JC124 also had significantly reduced protein expression levels of NLRP3, ASC, IL-1 beta, TNFα, iNOS, and caspase-1.

Conclusion

Our data suggest that our novel NLRP3 inhibitor has a specific anti-inflammatory effect to protect the injured brain following TBI.

Enduring Neuroprotective Effect of Subacute Neural Stem Cell Transplantation After Penetrating TBI

Traumatic brain injury (TBI) is the largest cause of death and disability of persons under 45 years old, worldwide. Independent of the distribution, outcomes such as disability are associated with huge societal costs. The heterogeneity of TBI and its complicated biological response have helped clarify the limitations of current pharmacological approaches to TBI management. Five decades of effort have made some strides in reducing TBI mortality but little progress has been made to mitigate TBI-induced disability. Lessons learned from the failure of numerous randomized clinical trials and the inability to scale up results from single center clinical trials with neuroprotective agents led to the formation of organizations such as the Neurological Emergencies Treatment Trials (NETT) Network, and international collaborative comparative effectiveness research (CER) to re-orient TBI clinical research. With initiatives such as TRACK-TBI, generating rich and comprehensive human datasets with demographic, clinical, genomic, proteomic, imaging, and detailed outcome data across multiple time points has become the focus of the field in the United States (US). In addition, government institutions such as the US Department of Defense are investing in groups such as Operation Brain Trauma Therapy (OBTT), a multicenter, pre-clinical drug-screening consortium to address the barriers in translation. The consensus from such efforts including “The Lancet Neurology Commission” and current literature is that unmitigated cell death processes, incomplete debris clearance, aberrant neurotoxic immune, and glia cell response induce progressive tissue loss and spatiotemporal magnification of primary TBI. Our analysis suggests that the focus of neuroprotection research needs to shift from protecting dying and injured neurons at acute time points to modulating the aberrant glial response in sub-acute and chronic time points. One unexpected agent with neuroprotective properties that shows promise is transplantation of neural stem cells. In this review we present (i) a short survey of TBI epidemiology and summary of current care, (ii) findings of past neuroprotective clinical trials and possible reasons for failure based upon insights from human and preclinical TBI pathophysiology studies, including our group's inflammation-centered approach, (iii) the unmet need of TBI and unproven treatments and lastly, (iv) present evidence to support the rationale for sub-acute neural stem cell therapy to mediate enduring neuroprotection.

Spontaneous preoperative pituitary adenoma resolution following apoplexy: a case presentation and literature review

Purpose: We aim to more fully understand the incidence and natural history of spontaneously resolving non-functioning pituitary adenomas (NFPAs).Methods: We report a case of spontaneous complete resolution of a NFPA revealed by preoperative magnetic resonance imaging. In addition, we searched all major databases and neurosurgery journals to perform a comprehensive literature review of all previously reported cases of spontaneously resolving NFPAs. We discuss how these cases may contribute to our understanding of the natural course for non-functional pituitary adenomas.Results: To date, only twelve cases of spontaneously resolving nonfunctional pituitary adenomas have previously been reported. The presented case is the first reported spontaneously resolved nonfunctioning pituitary adenoma to recur. In all cases, apoplexy resulted in resolution of mass effect, obviating the need for surgical decompression.Conclusions: In all NFPA cases, the preoperative MRI should always be studied closely before surgery is initiated. Additionally, because we have demonstrated that the adenoma may regrow after spontaneous regression following apoplexy, these patients should be followed with regular serial MRIs to monitor for recurrence.

Abstract P3-10-13: Bilateral breast cancer in China: A 10-year single-center retrospective study

BACKGROUD: Women with unilateral breast cancer are at increased risk for developing contralateral disease. The objective of the single-center retrospective study was to evaluate the incidence of bilateral breast cancer (BBC) and to analyze the clinicopathological characteristics for BBC in China.

METHODS: We retrospectively reviewed the electronic medical records of 3924 female patients with breast cancer consecutively treated at the department of Breast Oncology in the Peking University Cancer Hospital between 2006 and 2016. BBC was categorized as synchronous (within 6 months) or metachronous bilateral breast cancer (after 6 months of a first tumor). Patients with BBC were identified according to the criteria described by Chaudary et al. Patients with stage IV first breast cancer, and those who were found to have distant metastases between the first and second primary breast cancer were excluded. Analyses of demographic, clinicopathologic, and treatment characteristics were done between sBBC and mBBC.

RESULTS: The incidence of BBC in our population was 3.2% (127 of 3924). Of those, 2.5 % ( 99 of 3924) were metachronous bilateral breast cancer ( mBBC ), and 0.71 % (28 of 3924) were synchronous bilateral breast cancer ( sBBC ). The overall median age of the patients at first diagnosis was 45 years (range, 27-81 years). The age of onset of the first mBBC was significantly younger than that of sBBC ( p = 0.027). In mBBC subgroups, the median time interval between first and second tumors was 68 months (range, 7-342 months), and 80.8% of the second tumor were diagnosed within 10 years of the diagnosis of the first tumor. A positive family history of breast cancer was found in 25% of sBBC and 9.1% of mBBC ( p = 0.025). In ER-negative first tumor of mBBC, 56.1% of the second tumor were ER-positive. Mastectomy was the commonest surgery performed in these patients.

CONCLUSIONS: Our results confirmed the necessity of screening contralateral breast at the diagnosis of unilateral breast cancer and following-up for Chinese patients with breast cancer.

Citation Format: Li H, Jiang H, Zhang R, Shao B, Yan Y, Ran R, Di L. Bilateral breast cancer in China: A 10-year single-center retrospective study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-13.