Middle Frontal Gyrus and Area 55b: Perioperative Mapping and Language Outcomes

Background: The simplistic approaches to language circuits are continuously challenged by new findings in brain structure and connectivity. The posterior middle frontal gyrus and area 55b (pFMG/area55b), in particular, has gained a renewed interest in the overall language network.

Methods: This is a retrospective single-center cohort study of patients who have undergone awake craniotomy for tumor resection. Navigated transcranial magnetic simulation (nTMS), tractography, and intraoperative findings were correlated with language outcomes.

Results: Sixty-five awake craniotomies were performed between 2012 and 2020, and 24 patients were included. nTMS elicited 42 positive responses, 76.2% in the inferior frontal gyrus (IFG), and hesitation was the most common error (71.4%). In the pMFG/area55b, there were seven positive errors (five hesitations and two phonemic errors). This area had the highest positive predictive value (43.0%), negative predictive value (98.3%), sensitivity (50.0%), and specificity (99.0%) among all the frontal gyri. Intraoperatively, there were 33 cortical positive responses—two (6.0%) in the superior frontal gyrus (SFG), 15 (45.5%) in the MFG, and 16 (48.5%) in the IFG. A total of 29 subcortical positive responses were elicited−21 in the deep IFG–MFG gyri and eight in the deep SFG–MFG gyri. The most common errors identified were speech arrest at the cortical level (20 responses−13 in the IFG and seven in the MFG) and anomia at the subcortical level (nine patients—eight in the deep IFG–MFG and one in the deep MFG–SFG). Moreover, 83.3% of patients had a transitory deterioration of language after surgery, mainly in the expressive component (p = 0.03). An increased number of gyri with intraoperative positive responses were related with better preoperative (p = 0.037) and worse postoperative (p = 0.029) outcomes. The involvement of the SFG–MFG subcortical area was related with worse language outcomes (p = 0.037). Positive nTMS mapping in the IFG was associated with a better preoperative language outcome (p = 0.017), relating to a better performance in the expressive component, while positive mapping in the MFG was related to a worse preoperative receptive component of language (p = 0.031).

Conclusion: This case series suggests that the posterior middle frontal gyrus, including area 55b, is an important integration cortical hub for both dorsal and ventral streams of language.

Multicellular "hotspots" harbor high-grade potential in lower-grade gliomas

BACKGROUND

Lower-grade gliomas may be indolent for many years before developing malignant behavior. The mechanisms underlying malignant progression remain unclear.

METHODS

We collected blocks of live human brain tissue donated by people undergoing glioma resection. The tissue blocks extended through the peritumoral cortex and into the glioma. The living human brain tissue was cut into ex vivo brain slices and bathed in 5-aminolevulinic acid (5-ALA). High-grade glioma cells avidly take up 5-ALA and accumulate high levels of the fluorescent metabolite, Protoporphyrin IX (PpIX). We exploited the PpIX fluorescence emitted by higher-grade glioma cells to investigate the earliest stages of malignant progression in lower-grade gliomas.

RESULTS

We found sparsely distributed "hot-spots" of PpIX-positive cells in living lower-grade glioma tissue. Glioma cells and endothelial cells formed part of the PpIX hotspots. Glioma cells in PpIX hotspots were IDH1 mutant and expressed nestin suggesting they had acquired stem-like properties. Spatial analysis with 5-ALA-conjugated quantum dots indicated that these glioma cells replicated adjacent to blood vessels. PpIX hotspots were formed in the absence of angiogenesis.

CONCLUSION

Our data show that PpIX hotspots represent microdomains of cells with high-grade potential within lower-grade gliomas and identify locations where malignant progression could start.

Preoperative transcranial magnetic stimulation for picture naming is reliable in mapping segments of the arcuate fasciculus

In preoperative planning for neurosurgery, both anatomical (diffusion imaging tractography) and functional tools (MR-navigated transcranial magnetic stimulation) are increasingly used to identify and preserve eloquent language structures specific to individuals. Using these tools in healthy adults shows that speech production errors occur mainly in perisylvian cortical sites that correspond to subject-specific terminations of the major language pathway, the arcuate fasciculus. It is not clear whether this correspondence remains in oncological patients with altered tissue. We studied a heterogeneous cohort of 30 patients (fourteen male, mean age 44), undergoing a first or second surgery for a left hemisphere brain tumour in a language-eloquent region, to test whether speech production errors induced by preoperative transcranial magnetic stimulation had consistent anatomical correspondence to the arcuate fasciculus. We used navigated repetitive transcranial magnetic stimulation during picture naming and recorded different perisylvian sites where transient interference to speech production occurred. Spherical deconvolution diffusion imaging tractography was performed to map the direct fronto-temporal and indirect (fronto-parietal and parieto-temporal) segments of the arcuate fasciculus in each patient. Speech production errors were reported in all patients when stimulating the frontal lobe, and in over 90% of patients in the parietal lobe. Errors were less frequent in the temporal lobe (54%). In all patients, at least one error site corresponded to a termination of the arcuate fasciculus, particularly in the frontal and parietal lobes, despite distorted anatomy due to a lesion and/or previous resection. Our results indicate that there is strong correspondence between terminations of the arcuate fasciculus and speech errors. This indicates that white matter anatomy may be a robust marker for identifying functionally eloquent cortex, particularly in the frontal and parietal lobe. This knowledge may improve targets for preoperative mapping of language in the neurosurgical setting.

Management evaluation of metastasis in the brain (MEMBRAIN)-a United Kingdom and Ireland prospective, multicenter observational study

BACKGROUND

In recent years an increasing number of patients with cerebral metastasis (CM) have been referred to the neuro-oncology multidisciplinary team (NMDT). Our aim was to obtain a national picture of CM referrals to assess referral volume and quality and factors affecting NMDT decision making.

METHODS

A prospective multicenter cohort study including all adult patients referred to NMDT with 1 or more CM was conducted. Data were collected in neurosurgical units from November 2017 to February 2018. Demographics, primary disease, KPS, imaging, and treatment recommendation were entered into an online database.

RESULTS

A total of 1048 patients were analyzed from 24 neurosurgical units. Median age was 65 years (range, 21-93 years) with a median number of 3 referrals (range, 1-17 referrals) per NMDT. The most common primary malignancies were lung (36.5%, n = 383), breast (18.4%, n = 193), and melanoma (12.0%, n = 126). A total of 51.6% (n = 541) of the referrals were for a solitary metastasis and resulted in specialist intervention being offered in 67.5% (n = 365) of cases. A total of 38.2% (n = 186) of patients being referred with multiple CMs were offered specialist treatment. NMDT decision making was associated with number of CMs, age, KPS, primary disease status, and extent of extracranial disease (univariate logistic regression, P < .001) as well as sentinel location and tumor histology (P < .05). A delay in reaching an NMDT decision was identified in 18.6% (n = 195) of cases.

CONCLUSIONS

This study demonstrates a changing landscape of metastasis management in the United Kingdom and Ireland, including a trend away from adjuvant whole-brain radiotherapy and specialist intervention being offered to a significant proportion of patients with multiple CMs. Poor quality or incomplete referrals cause delay in NMDT decision making.

Primary Lumbar Paraganglioma: Clinical, Radiologic, Surgical, and Histopathologic Characteristics from a Case Series of 13 Patients

BACKGROUND

Paragangliomas are uncommon neuroendocrine tumors, rarely occurring in the lumbar spine. Primary lumbar paragangliomas are prominently vascularized, can present variably, and pose both diagnostic and surgical challenges. We report on a large case series with long-term follow-up and intraoperative footage to characterize the natural history, diagnostic approach, and operative approach to this rare surgical disease.

METHODS

This is a single-center, retrospective cohort study including all patients with histologically confirmed primary lumbar paraganglioma treated at our tertiary neurosurgical center between 1997 and 2018. Clinical, radiologic, surgical, and histologic data were collected from medical records.

RESULTS

There were 13 cases of primary lumbar paraganglioma (8 men [61.5%], 5 women [38.5%]; mean age, 51.3 years; range, 33.2-68.9 years). Symptom duration correlated with tumor size (Spearman r = 0.735, P = 0.01). The main presenting symptoms were lower back pain and radiculopathy, often long-standing with recent deterioration. Seven patients (53.8%) were admitted as emergency cases, including 3 with cauda equina syndrome. Preoperative differential diagnoses included nerve sheath tumor, ependymoma, meningioma, and disk herniation. The mean Ki-67 mitotic index was 5.7% (range, 1%-10%). Surgical resection improved pain in 8 of 13 patients (61.5%) and weakness improved in 5 of 5 patients (100%).

CONCLUSIONS

Primary lumbar paragangliomas are rare neoplasms of the cauda equina that typically progress slowly but may also present acutely. They are often related to the filum terminale, which should be resected prior to other attachments intraoperatively to prevent displacement of the tumor out of view. Total resection can be curative, and long-term follow-up in this series found no recurrence.

Pre- and Intraoperative Mapping for Tumors in the Primary Motor Cortex: Decision-Making Process in Surgical Resection

BACKGROUND

 Lesions within the primary motor cortex (M1) and the corticospinal tract (CST) represent a significant surgical challenge with a delicate functional trade-off that should be integrated in the overall patient-centered treatment plan.

METHODS

 Patients with lesions within the M1 and CST with preoperative cortical and subcortical mapping (navigated transcranial magnetic stimulation [nTMS] and tractography), intraoperative mapping, and intraoperative provisional histologic information (smear with and without 5-aminolevulinic acid [5-ALA]) were included. This independently acquired information was integrated in a decision-making process model to determine the intraoperative extent of resection.

RESULTS

 A total of 10 patients (6 patients with metastatic precentral tumor; 1 patient with grade III and 2 patients with grade IV gliomas; 1 patient with precentral cavernoma) were included in the study. Most of the patients (60%) had a preoperative motor deficit. The nTMS documented M1 invasion in all cases, and in eight patients, the lesions were embedded within the CST. Overall, 70% of patients underwent gross total resection; 20% of patients underwent near-total resection of the lesions. In only one patient was no surgical resection possible after both preoperative and intraoperative mapping. Overall, 70% of patients remained stable postoperatively, and previous motor weakness improved in 20%.

CONCLUSION

 The independently acquired anatomical (anatomical MRI) and functional (nTMS and tractography) tests in patients with CST lesions provide a useful guide for resection. The inclusion of histologic information (smear with or without 5-ALA) further allows the surgical team to balance the potential functional risks within the global treatment plan. Therefore, the patient is kept at the center of the informed decision-making process.

Altered corticospinal microstructure and motor cortex excitability in gliomas: an advanced tractography and transcranial magnetic stimulation study

OBJECTIVE

This prospective case-control study was conducted to examine whether spherical deconvolution (SD) can unveil microstructural abnormalities in the corticospinal tract (CST) caused by IDH-mutant gliomas. To determine the significance of abnormal microstructure, the authors investigated the correlation between diffusion parameters and neurophysiological data collected with navigated transcranial magnetic stimulation (nTMS).

METHODS

Twenty participants (10 patients and 10 healthy controls) were recruited. Diffusion-weighted images were acquired on a 3-T MRI scanner using a cardiac-gated single-shot spin echo echo-planar imaging multiband sequence (TE 80 msec, TR 4000 msec) along 90 diffusion directions with a b-value of 2500 sec/mm2 (FOV 256 × 256 mm). Diffusion tensor imaging tractography and SD tractography were performed with deterministic tracking. The anterior portion of the ipsilateral superior peduncle and the precentral gyrus were used as regions of interest to delineate the CST. Diffusion indices were extracted and analyzed for significant differences between hemispheres in patients and between patient and control groups. A navigated brain stimulation system was used to deliver TMS pulses at hotspots at which motor evoked potentials (MEPs) for the abductor pollicis brevis, first digital interosseous, and abductor digiti minimi muscles are best elicited in patients and healthy controls. Functional measurements such as resting motor threshold (rMT), amplitude of MEPs, and latency of MEPs were noted. Significant differences between hemispheres in patients and between patients and controls were statistically analyzed. The Spearman rank correlation was used to investigate correlations between diffusion indices and functional measurements.

RESULTS

The hindrance modulated orientational anisotropy (HMOA), measured with SD tractography, is lower in the hemisphere ipsilateral to glioma (p = 0.028). The rMT in the hemisphere ipsilateral to a glioma is significantly greater than that in the contralateral hemisphere (p = 0.038). All measurements contralateral to the glioma, except for the mean amplitude of MEPs (p = 0.001), are similar to those of healthy controls. Mean diffusivity and axial diffusivity from SD tractography are positively correlated with rMT in the hemisphere ipsilateral to glioma (p = 0.02 and 0.006, respectively). The interhemispheric difference in HMOA and rMT is correlated in glioma patients (p = 0.007).

CONCLUSIONS

SD tractography can demonstrate microstructural abnormality within the CST of patients with IDH1-mutant gliomas that correlates to the functional abnormality measured with nTMS.

5-ALA fluorescence in a WHO grade I papillary glioneuronal tumour: a case report

5-ALA is proven to be effective in high-grade glioma operative resection. The use of 5-ALA in WHO grade I lesions is still controversial. A 49-year-old lady was diagnosed in 2004 with a left temporal lobe lesion as an incidental finding; she was followed up clinically and radiologically. In 2016, the lesion showed contrast enhancement and she was offered surgical resection but given she is asymptomatic, she refused. In 2018, the lesion showed signs of transformation with ring contrast enhancement, increased vasogenic oedema and perfusion; the patient accepted surgery at that point. She had preoperative mapping by navigated transcranial magnetic stimulation and she had operative resection with 5-ALA. The tumour was bright fluorescent under Blue 400 filter—Zeiss Pentero 900©(Carl Zeiss Meditec)—and both bright fluorescence and pale fluorescence were resected. Postoperative MRI showed complete resection and histopathology revealed WHO grade I papillary glioneuronal tumour, negative for BRAF V600 mutation. WHO grade I papillary glioneuronal tumour may present as 5-ALA fluorescent lesions. From a clinical perspective, 5-ALA can be used to achieve complete resections in these lesions which, in most cases, can be curative.

Reliability of Intraoperative Monitoring in Patients with a Preexisting Motor Deficit: Case Report and Literature Review

BACKGROUND

 The use of intraoperative monitoring (IOM) in glioma surgery is a widely adopted and clinically validated adjunct to define safe zones of resection for the neurosurgeon. However, the role of IOM in cases of a significant preexisting motor deficit is questionable.

CASE DESCRIPTION

 We describe a case of a 25-year-old with a recurrent presentation of a left paracentral glioblastoma, admitted with intratumoral hemorrhage and subsequent acute severe right-sided weakness. The patient underwent a redo left parietal craniotomy and 5-aminolevulinic acid-guided resection with IOM. The severity of the weakness was not reflected by the pre- and intraoperative cortical motor evoked potentials (MEPs) that were reassuring. The patient's hemiparesis recovered to full power postoperatively.

CONCLUSIONS

 Preoperative weakness is traditionally accepted as a relative contraindication to IOM and therefore its usefulness is questioned in this context. Our case challenges this assumption. We present the clinical course, review the cranial and spinal literature including the reliability of IOM in cases of preoperative motor deficit, and discuss the need for tailor-made IOM strategies.

Ex vivo ultrasonic samples of human brain tumors in the molecular era

Background

Gliomas are composed of multiple clones of tumor cells. This intratumor heterogeneity contributes to the ability of gliomas to resist treatment. It is vital that gliomas are fully characterized at a molecular level when a diagnosis is made to maximize treatment effectiveness.

Methods

We collected ultrasonic tissue fragments during glioma surgery. Large tissue fragments were separated in the operating theater and bathed continuously in oxygenated artificial cerebrospinal fluid to keep them alive. The ex vivo tissue fragments were transferred to a laboratory and incubated in 5-aminolevulinic acid (5-ALA). 5-ALA is metabolized to Protoporphyrin IX (PpIX), which accumulates in glioma cells and makes them fluorescent. The molecular and neuropathological features of the PpIX fluorescent ultrasonic tissue fragments were studied.

Results

We show that PpIX fluorescence can rapidly identify tissue fragments infiltrated by glioma in the laboratory. Ultrasonic tissue fragments from the tumor core provided molecular and neuropathological information about the glioma that was comparable to the surgical biopsy. We characterized the heterogeneity within individual gliomas by studying ultrasonic tissue fragments from different parts of the tumor. We found that gliomas exhibit a power relationship between cellular proliferation and tumor infiltration. Tissue fragments that deviate from this relationship may contain foci of more malignant glioma. The methylation status of the O ⁶-methylguanine DNA methyltransferase gene promoter varied within each glioma.

Conclusions

Ex vivo ultrasonic tissue fragments can be rapidly screened for glioma infiltration. They offer a viable platform to characterize heterogeneity within individual gliomas, thereby enhancing their diagnosis and treatment.

Safety and accuracy of frameless electromagnetic-navigated (AXIEMTM)-guided brain lesion biopsies: a large single-unit study

BACKGROUND

Brain biopsies are required to establish a definitive histological diagnosis for brain lesions that have been identified on imaging in order to guide further treatment for patients.

OBJECTIVE

Various navigation systems are in use but little up to date evidence is available regarding the safety and accuracy of a frameless, electromagnetic technique to target brain lesions.

METHODS

Data was collected retrospectively on all patients that had brain biopsies at our institution from 01/01/2010 to 31/12/2017. Operation notes, neuropathology reports, and clinical notes on electronic patient record were used to determine whether biopsy of adequate identifiable abnormal tissue was achieved, whether a definitive diagnosis was established, any adverse events occurred, and if a repeat biopsy was carried out.

RESULTS

Three hundred seventy-one AxiEM (Medtronic, Minneapolis, USA)-guided brain tumor biopsies were performed in this 8-year period. Three hundred forty-nine (94.07%) procedures provided definitive tissue diagnosis, 22 (5.93%) were non diagnostic; in 6 cases (1.62%), repeat biopsy was performed and adverse events which caused clinical compromise were observed in 4 patients (1.08%).

CONCLUSIONS

The AxiEM is a fast, effective, and safe frameless and pinless neuronavigational system. It offers a high degree of accuracy required for the establishment of a definitive diagnosis, permitting optimal further treatment, and thus improving patient outcomes.

Transformation of Grade II to Grade III Rhabdoid-Papillary Meningioma: Is Stereotactic Radiosurgery the Culprit? A Case Report and Literature Review

BACKGROUND

In the management of meningiomas, single-fraction stereotactic radiosurgery (SRS) is an established alternative treatment to surgical resection. However, its effects on tumorigenesis and malignant transformation are still uncertain.

CASE DESCRIPTION

We have described a grade II parafalcine meningioma that was initially surgically resected (Simpson 2 clearance) and then managed with a single dose of SRS on recurrence. The tumor recurred again 7 years later, with histological features of a grade III rhabdoid-papillary lesion, with local brain invasion.

CONCLUSION

To the best of our knowledge, this is the first report to describe malignant transformation of a grade II to grade III meningioma after SRS to date.

Delayed heamatoma after melanoma metastasis resection upon restart of Immunotherapy: Case Report and Review of the Literature

Background

Supratentorial Metastatic Melanomas are common and increasingly treated with immunotherapy. While improving the outcome, the immunotherapy potentially increases the risks of the intracranial surgical procedures, particularly bleeding. However, scarce reports address this complications.

Case Description

A 52-year old male with a history of right upper limb excised skin lesion resected with wide local excision 6 months prior to admission, who presented with a three weeks history of progressive headaches, vomiting, odd behaviours, forgetfulness, and left lower sided weakness. Brain imaging showed a right frontal lesion with evidence of haemorrhage within it with midline shift and mass effect. He underwent craniotomy and resection of the lesion with no post-operative complication, resolution of left sided hemiparesis and post-operative imaging documenting complete resection and no post-operative complications. The histopathology confirmed metastatic melanoma and he received adjuvant immunotherapy (Nivolumab), however he represented 4 weeks post operatively with sudden onset headache with vomiting with no neurological deficit, brain imaging showed a delayed hematoma in the surgical site.

Conclusions

This case report highlights the risk of post-operative bleeding with the immunotherapy and paves the way for further studies with regards to the safety of immunotherapy after intracranial procedures

Primary lumbar paraganglioma: A single-centre UK experience over 21 years

Objectives

Paragangliomas are rare neuro-endocrine neoplasms which may occur at multiple anatomical sites, typically the adrenal glands. In the CNS, they can affect the head and neck, and more rarely the lumbar region. Primary lumbar paragangliomas are prominently vascularised lesions which can present variably and pose both diagnostic and surgical challenges.

Methods

We identified and analysed all cases of lumbar paraganglioma confirmed both surgically and histologically, treated at our regional neurosurgical centre. We collected retrospective clinical, radiological, surgical and histological data.

Results

We treated 25 patients with confirmed paraganglioma between 1997–2018. This included 19 primary tumours, of which 13 cases of primary lumbar paraganglioma (8 males (61.5%); mean age 51.3 years, range 33.2 – 68.9).

Patients presented most frequently with a recent worsening of long-standing lower back pain and sciatica. 7 patients were admitted as emergency cases, including 3 with cauda equina syndrome. The average Ki67 mitotic index was 5.7% (range 1 – 10%).

Conclusion

We present one of the largest case series of primary lumbar paragangliomas to date to the best of our knowledge. Defining these clinical, radiological, surgical and histological features may be of assistance in recognising and managing this surgical disease.

Grade III meningioma: 10 year single centre case series

Rationale

WHO Grade 3 meningiomas are a rare, malignant subtype of meningioma. Few controlled case series detailing its treatment and follow-up are to be found in the literature.

Methods

Retrospective cohort study of patients treated in a single neuro-oncology centre in the period between September 2008 and March 2019 with an initial diagnosis of WHO Grade 3 meningioma. Demographic and clinical data has been collected from the available medical records.

Results

9 patients were included in this series: 2 had convexity, 2 sphenoid wing, 2 parafalcine, 1 parasagittal with a further 3 multiple locations and 1 patient with parietal convexity meningioma. 3 tumours displayed rhabdoid features, whilst 4 displayed papillary features and a further 2 displayed epithelial structures. All patients underwent surgical intervention: 5 patients had a subtotal resection with 3 having total resection. 3/4 of reported Simpson Grading was grade 2, whilst the remaining 1/4 was grade 1. The extent of resection for 1 patient was uncertain. Post surgically, 6 received adjuvant radiotherapy, 2 had no further treatment and 1 received gamma knife therapy. No patient received chemotherapy. 5 patients saw no tumour recurrence at follow up appointments (mean 50 months). Within 2 years of their respective surgical interventions, 4 patients died due to tumour recurrence and associated complications (3 patients).

Conclusion

To establish a uniform approach to treatment of patients with WHO Grade 3 meningiomas is challenging. Management involves a patient-centred approach based on multidisciplinary meeting decisions. Multicentre registries may allow further conclusions.

Transformation of grade II to grade III rhabdoid-papillary meningioma: Is SRS the culprit?

Objectives

Meningiomas demonstrate specific genetic and epigenetic mutations, whose effect on recurrence and progression is still of limited understanding. Single-fraction stereotactic radiosurgery (SRS) is an established alternative treatment to surgical resection, proven to achieve excellent local disease control with minimal side effects. However, its effects on tumorigenesis and malignant transformation are still uncertain. The published estimated risk ranges from 0.04%-2.6% at 15 years.

Design

Case report

Subjects

Female patient referred to our neurosurgical service

Methods

Retrospective analysis of patient’s notes, histopathology reports, clinic letters, MDT decisions and imaging studies

Results

This report describes a case of a grade II parafalcine meningioma, that was initially resected with a Simpson 2 clearance, and upon recurrence, was managed with a single dose of SRS. More than 7 years later, the meningioma recurred, and due to its increasing size on follow-up imaging, it was re-resected. Histopathology revealed a grade III rhabdoid-papillary lesion, with local brain invasion.

Conclusions

To our knowledge, this was the first report to describe malignant transformation of a grade II to a grade III meningioma following SRS therapy to date. Therefore, considering the recent trend towards SRS-treatment for meningiomas, the treating team should always consider its potential effects on tumorigenesis.

Spontaneous glioma-induced seizures recorded in a living human brain tissue preparation

Gliomas often present clinically with seizures. Tumour-associated seizures can be difficult to control with medication. A deeper understanding of the cellular mechanisms underlying tumour-associated seizures would provide a basis for developing new treatments. Here, we investigate epileptic discharges in peritumoral cortex using living human brain tissue donated by people having a craniotomy for glioma resection (REC approval, 18/SW/002). The brain tissue was cut into thin slices, which preserved the architecture of the glioma and the adjacent healthy brain. The brain slices were incubated in 5-aminolevulinic acid to make the glioma cells fluorescent. This enabled us to make electrophysiological recordings of brain activity across the boundary between glioma and brain. We recorded from brain slices of 5 participants with glioblastoma and 4 participants with oligodendroglioma (WHO grade II – III). Spontaneous “seizure-like” discharges were recorded in brain slices from 5/8 participants (3 GBM, 2 oligodendroglioma) who reported seizures and from one participant (GBM) who had not had any clinical seizures. Further analysis of the seizure-like discharges revealed that they could be subdivided into two distinct types based on the major frequencies in the discharge. We concluded that human brain slices from people with either a low-grade or a high-grade glioma can generate spontaneous seizure-like discharges. The living human brain tissue preparation gives us a platform to study the mechanisms of tumour-associated seizures and how abnormal neural activity affects glioma growth.

Low grade glioma patients: how does this patient group perceive their quality of life prior to surgical or oncological interventions?

Introduction

Literature analysing how patients with a provisional low-grade glioma perceive their own quality of life prior to any surgical or oncological intervention is scarce. This patient group are often highly functioning individuals, able to lead ordinary lives which stresses that their management must be carefully considered in a holistic sense. Low grade gliomas represent 5 % of brain tumours and they are typically of a younger cohort who will be less equipped to manage the uncertainties a diagnosis like this brings.

Methods

Prospective single centre cohort study over 14 months where 56 patients completed the EORTC QLQ – BN 20 and 30 prior to initial consultation in the dedicated low grade glioma clinic.

Results

54% of patients did not feel ‘limited in doing work or other daily activities’ but of those who were affected to some degree, 21% of women felt ‘very much affected’ compared to 3% of men. 78% of patients expressed to a degree some ‘uncertainty about the future’ and this was shown to be a common theme among all age groups which reflects the huge burden of anxiety this patient group faces regardless of age.

Conclusion

Data demonstrated a variety of quality of life scores that are not particular to a certain age group/gender which reinforces the importance of individual assessment as assumptions of patients in a particular category cannot be made. By assessing quality of life, clinical management is improved as a more in-depth assessment is facilitated on an individual basis and patient experience is enhanced.

Supratentorial and Infratentorial Ependymomas in Adult Population - A 10-year single institution case series

Objectives

Analyse clinical characteristics and treatment provided to an adult population diagnosed with intracranial ependymomas between 2009–2018.

Methods

Single centre retrospective cohort study. Variables reviewed: demographics, extent of resection, adjuvant oncological treatment and molecular genetics.

Results

17 patients were included (6 females, 11 males). Average age at presentation was 51.3 yrs (range 19-74yrs). 4 supratentorial (2 intraventricular, 1 temporal lobe and 1 frontal lobe) and 13 infratentorial lesions were identified.

In the supratentorial subgroup the following treatment was performed: GTR (1 patient), STR (1 patient) and Biopsy (2 patients); 2 patients underwent post-operative radiotherapy. 3 patients had a WHO grade 2 tumour (1 patient - insufficient tissue for grading). 3 recurrences were identified and 2 patients had re-debulking. 2 patients had postoperative hemiparesis, 1 patient died during treatment and 3 are currently being followed up.

In the infratentorial subgroup the following treatment was performed: GTR (5 patients), STR (7 patients) and biopsy (1 patient). 3 patients underwent post-operative radiotherapy. 1 patient was WHO grade 1, 11 patients were WHO grade 2 and 1 patient was WHO grade 3. 2 patients had tumour recurrences of which 1 was re-operated. 7 patients develop new post-operative deficits after surgery; 1 patient died and the rest are currently being followed up.

Conclusion

Even though this case series supports the good prognosis in terms of overall survival in adults with intracranial ependymomas, they represent a challenge to manage given the morbidity of optimal surgical resection and their poor response to adjuvant treatment.

Combined extradural-interdural-intradural approach to a trigeminal nerve cystic haemangiopericytoma with intra-operative cranial nerve monitoring

Objectives

Haemangiopericytoma of the trigemimal nerve is extremely rare, with only two previous cases described to our knowledge. We present the surgical approach to this tumour, and describe a previously poorly reported method of monitoring the function of the branches of the trigeminal nerve: mapping of the sensory roots through transcranial somatosensory cortex sensory evoked potentials (SSEPs), motor evoked potentials (MEP) for the motor root and blink reflex.

Design

Case and technical reports

Subjects

32 year-old male patient presenting with headaches and vomiting, found to have a mixed cystic-solid tumour of the left middle skull base region, in close relation with the foramen ovale and Meckel’s cave.

Methods

The radiological features of the tumour, technical aspects of the technical approach and neurophysiologic monitoring will be described.

Results

A pterional craniotomy with fronto-temporal extradural-interdural-intradural approach, and the tumour was debulked with MEP, SSEP and blink reflex monitoring of the branches of the trigeminal nerve. Complete tumour removal was achieved with no post-operative cranial nerve deficits.

The histopathology revealed a cystic haemangiopericytoma.

Conclusions

Haemangiopericytoma is a rare entity. MEP and SSEP monitoring of the trigeminal nerve can be used to achieve complete and safe removal of the tumour.

Redo-Surgery for Recurrent Glioblastoma: A 10-year single-institution series

Introduction

Multiple surgeries for recurrent / progressive glioblastomas is a matter of debate within the neuro-oncology community reflecting the higher risk of complications and the limited adjuvant treatment options for patients who recurred after initial treatment. Therefore it is crucial to identify who may benefit of a more aggressive approach and if the neurosurgical practice has changed in the last years.

Methods

Single-Neuro-Oncology Surgical Centre (1 neurosurgical and 2 medical neuro-oncology units) retrospective cohort study of patients with more than one surgery for intracranial Glioblastoma Multiforme (GBM). All patient diagnised with GBM at the time of the first surgery in the period between 2009–2018. Second surgery within 2-months time following initial biopsy or surgical complication or prior to chemo-radiotherapy were excluded. Demographic and clinical data was collected from the medical records.

Results

96 patients underwent second surgery (63 males, 33 females, mean age of 52.6) met criteria for surgery at progression. At the time of the first surgery, the extent of resection (EOR) was: 15 biopsy, 17 subtotal rescetion (STR) and 35 gross total resection (GTR) – 29 missing data. With regards to the molecular markers, 26 were IDH mutant, 73 were MGMT methylated. All of the patients recieved adjuvant chemoradiotherapy following the STUPP protocol prior.

Conclusion

Our data corresponds to the data in the current literature. Further qualitative study will provide an insight into the effectiveness and aggressive approach to the recurrent GBMs.

Patient Reported Experience Measures in navigated Transcranial Magnetic Stimulation

Introduction

Navigated Transcranial Magnetic Stimulation (nTMS) is a non-invasive adjunct used in surgical planning for lesions in eloquent brain. However, its patient tolerability and effect on their overall healthcare experience is still unknown. To our knowledge, there is no other literature available evaluating patient experience with nTMS.

Methods

A single-institution prospective cohort study carried out between February 2018 and December 2018 at King’s College Hospital. All patients were supplied with a PREMs-TMS questionnaire to evaluate the different domains of the nTMS experience.

Results

Feedback was obtained from 50 patients. 26% of patients underwent motor mapping (MM), whilst 74% underwent both motor and language mapping (MLM). The former group reported a better overall experience (p=0.020). The mean exam duration was 103.3±5.1 min (MM 85.8±6.1 min; MLM 106.9±5.9 min). The whole experience of nTMS received positive feedback (94%), particularly with confidence in the staff (95%). Unsurprisingly, the exam domain received a poorer rating (70% as good) with significant anxiety and pain reported in 26% and 24% of patients respectively. None of the studied variables influenced the way patients rated the overall experience of nTMS (p>0.05).

Conclusions

nTMS is a non-invasive investigative tool, which allows patients to better understand their condition and symptoms related to their lesion. Serial assessment and feedback using a PREM tool, can only improve and enhance this experience. Departmental collaboration may be useful in comparing patient experience with nTMS in different centres.

P11.49 An electrophysiological signature of glioma infiltration in the ex vivo human brain

BACKGROUND

Invading glioma cells affect the physiological function of the peritumoural cortex. This may manifest clinically as seizures. Here, we investigate the effect the invading glioma cells on the electrophysiological signalling of the peritumoral cortex using living human brain tissue donated by people having a craniotomy for glioma resection (REC approval, 18/SW/002).

MATERIAL AND METHODS

The brain tissue was cut into thin slices, which preserved the architecture of the glioma and the adjacent healthy brain. The brain slices were incubated in 5-aminolevulinic acid to make the glioma cells fluorescent. We observed 5-ALA induced fluorescence in both low-grade and high-grade gliomas. This enabled us to make electrophysiological recordings of brain activity across the boundary between glioma and brain.

RESULTS

We recorded from brain slices of 5 participants with glioblastoma and 4 participants with oligodendroglioma (WHO grade II - III). Spontaneous “seizure-like” discharges were recorded in brain slices from 5/8 participants (3 GBM, 2 oligodendroglioma) who reported seizures and from one participant (GBM) who had not had any clinical seizures. Further analysis of the electrical discharges revealed that they could be subdivided into two distinct types based on the major frequencies in the discharge.

CONCLUSION

We concluded that human brain slices from people with either a low-grade or a high-grade glioma can generate spontaneous seizure-like discharges. This electrophysiological signature will be compared to infiltration and grade of the glioma cells in the donated sample. The living human brain tissue preparation gives us a platform to study the mechanisms of tumour-associated seizures and how abnormal neural activity affects glioma growth.

P6 The use of 5-ALA fluorescence in excision of supratentorial endodermal cyst

Objectives

The first documented use of 5-ALA in the excision of an intraparenchymal endodermal cyst.

Design

Case review.

Subjects

52 year old female presented with headaches, progressive right sided hemiparesis and anomic aphasia. She had a large cystic frontal lesion, adjacent of the frontal horn of the lateral ventricles cyst which did not show any nodular or solid component, and did not enhance with gadolinium.

Methods

Case report and review of the literature.

Results

5-ALA assisted, image guided fenestration of the cystic lesion and insertion of a ventricular catheter connected to an Ommaya reservoir was performed. The cyst wall was observed under the microscope and it fluoresced with 5-ALA. Multiple biopsies were obtained from this tissue, which confirmed diagnosis of endodermal cyst. The patient had improvement in clinical symptoms and size of the cyst radiologically in both the immediate post-operative period and the 6 months follow up.

Conclusions

Previous reports described the use of 5-ALA to identify tumour cells within the solid component of cystic haemangioblastomas as well as in cystic ependymomas where the cystic component does not fluoresce. In our patient, the homogeneous fluorescence of the wall suggested that this was indeed a different entity from a haemangioblastoma or an ependymoma because of the different pattern of fluorescence observed. 5-ALA-assisted resection of cystic lesions should be considered when a tumoral origin is uncertain.

WP1-17 Risk factors and patterns of progression in a surgical cohort of low grade glioma patients

Objectives

To understand the risk factors for and patterns of progression of low grade glioma (LGG).

Design

Single centre retrospective cohort study.

Subjects

Patients undergoing at least two neurosurgical procedures for LGG, the first being for diffuse LGG (WHO 2). 22 patients included (14M; 8F); mean age at time of first operation 37.7±2.7 years. 20 patients had a Performance Status (PS) 0–1 and 2 patients had a PS 2.

Methods

All patients with LGG diagnosed in between 2009–2018 were retrospectively evaluated. Variables of interest included demographics, staging, performance status, time to re-operation (TTR), extent of resection, molecular genetics (1p19q co-deletion, IDH status). Tumour volumes were estimated from MRI images by the validated ABC/2 equation. Statistical analyses were performed by Stata13.0.

Results

The tumour progressed in WHO grade in 18 patients (WHO grade 3 (n=15); WHO grade 4 (n=3). Mean time to re-operation after the first surgery was 7.0±1.2 years following gross total resection (GTR) and 3.2±0.7 years following subtotal resection (STR). Non-adjusted analysis of risk factors for time to re-operation (TTR) showed absence of 1p19q co-deletion as a risk factor (p=0.021). Adjusted analysis revealed that GTR, 1p19q mutation, PS 0 at 1 st surgery and tumour volumetric change decrease the risk for re-intervention (p<0.05). Chemo-radiotherapy was not associated with TTR.

Conclusions

In our cohort, TTR in LGG was influenced by the amount of initial resection, 1p19q deletion, PS and post-operative volumetric change.

WP1-18 Risk factors and patterns of recurrence of low grade glioma: a systematic review

Objectives

To review the risk factors and patterns of progression/recurrence of low grade glioma (LGG).

Design

Systematic review of the published literature.

Subjects

Inclusion criteria were peer reviewed publications of cohort studies of recurrent/progressive LGG. Studies of wider populations were included if relevant LGG data could be analysed separately.

Methods

Medline and Cochrane databases were searched using MeSH and non-MeSH terms, including ‘glioma’, ‘astrocytoma’, ‘oligoastrocytoma’, ‘diffuse glioma’, ‘oligodendroglioma’, ‘low grade’ and ‘disease recurrence’ by two independent reviewers.

Results

Overall, 917 studies were screened, of which 57 studies met the inclusion criteria. The most frequently described risk factor for recurrent LGG was suboptimal extent of resection (EOR) of the initial tumour (in 20 studies); recurrence was also associated with the patient’s age (2), tumour location (4), neurological status (3), tumour volume (6), bihemispherical tumour (3) and astrocytic histology (6). IDH mutation was associated with recurrence in 1 out of 3 studies, but TP53 mutation (2 of 4) and MGMT methylation status (4) were not. Malignant transformation was associated with TP53 mutations (3), IDH mutation (1) and EOR (1). Favourable progression free survival (PFS) and/or overall survival (OS) were associated with greater EOR (16), oligodendroglioma histology (2 of 4), initial KPS (3) and the use of adjuvant therapies (9 of 14). IDH mutation was associated with improved PFS and OS (3 of 4). TP53 mutation improved PFS in 1 of 3 studies. MGMT methylation and 1 p/19q codeletion may predict treatment response but their effects on survival are unclear.

Conclusions

Astrocytoma histology, IDH and TP53 mutation statuses and surgical treatment (EOR) are essential in determining the time to recurrence or progression in LGG.

Grade II Sylvian fissure meningiomas without dural attachment: case report and review of the literature

Sylvian fissure meningiomas (SFMs) represent a rare subgroup of nondural-based tumors arising from the meningothelial cells within the arachnoid of the Sylvian fissure. SFMs are more frequent in young males, usually manifest with seizures and display the same radiological features of meningiomas in other locations. Although the absence of dural attachment makes these tumors suitable for a complete resection, their anatomical relationships with the middle cerebral artery branches have impaired its achievement in half of them. To the best of our knowledge, only five atypical WHO grade II SFMs have been previously described. We provide a literature review of SFMs WHO grades I-II and discuss common characteristics and surgical challenges we found in a similar case.

Factors Influencing Medical Student Interest in a Career in Neurosurgery

BACKGROUND

Exposure to neurosurgery at the undergraduate level is an important factor in determining future interest in and applications to the specialty. Given the high competition for training posts, this exposure is also becoming an almost essential addition to an applicant's portfolio. We organized a neurosurgical conference aimed at undergraduate medical students. The aim of this study was to determine factors attracting and deterring students from the specialty before and after the conference.

METHODS

Responses were collected prospectively from students attending a national neurosurgical conference organized by medical students with support from the local neurosurgical unit. Questionnaires were distributed before and after the conference examining students' perceptions of a career in neurosurgery using free-text responses.

RESULTS

Poor lifestyle or work-life balance was the most important factor deterring students from a career in the specialty both before (29.7%) and after (60%) the conference. The most important factor attracting students to the specialty before the conference was the practical (surgical approaches and techniques) aspect (21.9%). After the conference, the most important attracting factor was the rewarding nature of the specialty (18.9%).

CONCLUSIONS

The most notable factor deterring students from a career in neurosurgery was work-life balance. Other deterring factors were much less prevalent following the conference. Understanding how exposure to neurosurgery influences students' perceptions is important for developing future initiatives to prevent misconceptions and allow students to make informed choices as well as encourage the right candidates to apply.

Navigated Transcranial Magnetic Stimulation in Patient with Cranioplasty in Situ: Safe and Accurate Procedure

BACKGROUND

Navigated transcranial magnetic stimulation (nTMS) is a nonsurgical mapping technique used in mapping of motor and language eloquent areas within and/or surrounding brain tumors. Previous reports support this as a safe technique with minor side effects associated with minor headaches and discomfort around the stimulation area. Currently there are no published reports concerning the accuracy and safety of this procedure in patients with a titanium cranioplasty in situ.

CASE PRESENTATION

A 59-year-old lady was diagnosed with a recurrent glioma in the context of increasing seizure frequency, left-sided numbness, and weakness. She was diagnosed with a World Health Organization grade 2 oligodendroglioma 10 years before her presentation, which was initially treated with radiotherapy and then surgical resection of this lesion 5 years later. The procedure was complicated with a wound infection, treated with a craniectomy and wound washout, followed by a titanium cranioplasty. Before proceeding with surgery for recurrence, nTMS was performed for motor mapping. No complications were identified. She underwent a craniotomy for tumor resection with aminolevulinic acid HCl (Gliolan), and the tumor was completely removed. Intraoperatively, the direct cortical stimulation correlated with the preoperative nTMS. The pathologic diagnosis on recurrence was an anaplastic oligodendroglioma grade III, and the patient is currently undergoing adjuvant chemotherapy.

CONCLUSION

This report confirms that nTMS is a safe and accurate procedure in patients who have a titanium cranioplasty in situ.

Posterior longitudinal ligament and its implications in intradural cervical disc herniation: Case report and review of the literature

BACKGROUND

Intradural disc herniations (IDH) are rare, particularly in the cervical spine, where they account for less than 5% of all discs. Adhesions between the ossified/calcified posterior longitudinal ligament (OPLL), dura, and ossified/calcified disc herniations increase the complexity of resecting these cervical lesions.

CASE DESCRIPTION

A 42-year-old male presented with a rapidly progressive cervical myelopathy over a 2-month period. This was attributed to an ossified/calcified intradural cervical disc herniation in conjunction with OPLL. The anterior cervical discectomy and fusion (ACDF) resulted in a dural defect but there was no cerebrospinal fluid (CSF) fistula as the arachnoid membrane remained intact. Had there been a CSF leak, it would have warranted both wound-peritoneal (WP) and lumbo-peritoneal shunts (LP). The surgeons should have anticipated that a CSF leak would likely occur prior to performing the ACDF, and should have prophylactically prepared and draped the abdomen for a potential WP, followed by a LP shunt. Three months postoperatively, the patient's proprioceptive deficit improved, and he almost completely recovered motor function.

CONCLUSION

Performing an ACDF for resection of an intradural calcified/ossified disc with OPLL often results in both a dural defect and CSF fistula. As the arachnoid membrane rarely remains intact, the spine surgeon should be prepared to immediately perform both a WP shunt, and subsequently, an LP. In this case, following an ACDF, resection of an intradural ossified disc with OPLL resulted in an isolated dural defect without a CSF fistula and did not require no dural repair or shunting procedures.

Primary intracerebral INI1-deficient rhabdoid tumor with CD34 immunopositivity in a young adult

Background:

Primary CNS malignant rhabdoid tumors are very rare in adults and much less is known about their biological behavior than in children. Recently, two adult cases of SMARCB1 (also known as INI1)-deficient tumor with rhabdoid cells have been described, suggesting an emerging group of primary meningeal SMARCB1-deficient tumors. We have recently encountered a case of INI1-deficient tumor with similar histology and immunophenotype to the above cases, but with a superficial cerebral, yet apparent intra-axial origin.

Case Description:

A 22-year-old woman presented with approximately one year history of focal sensorimotor right upper limb seizures and recently developed a slowly progressive weakness in her right hand. An MRI of the brain demonstrated an avidly enhancing lesion centered on the left perirolandic region with no definite dural involvement. The patient underwent a complete surgical excision. Histology revealed a tumor with monotonous epithelioid and spindle-shaped cells in a mucoid/myxoid background. There was focal mitotic activity and a few necrotic areas, in addition to many rhabdoid cells. The immunohistochemistry was negative for INI1 and there was strong positivity with CD34, while focal smooth muscle actin (SMA) and epithelial membrane antigen (EMA) immunoreactivity were also noted.

Conclusions:

As an addition to the two cases of adult SMARCB1-deficient tumors recently described, we present a further adult case with a similar immunohistochemical profile but with an apparent intra-axial origin, questioning the necessary meningeal origin of this type of tumor. The prognosis of this adult INI1/SMARCB1-deficient tumor is to be determined, but may be better than the pediatric atypical/teratoid tumor (AT/RT).

Recent technological advances in pediatric brain tumor surgery

X-rays and ventriculograms were the first imaging modalities used to localize intracranial lesions including brain tumors as far back as the 1880s. Subsequent advances in preoperative radiological localization included computed tomography (CT; 1971) and MRI (1977). Since then, other imaging modalities have been developed for clinical application although none as pivotal as CT and MRI. Intraoperative technological advances include the microscope, which has allowed precise surgery under magnification and improved lighting, and the endoscope, which has improved the treatment of hydrocephalus and allowed biopsy and complete resection of intraventricular, pituitary and pineal region tumors through a minimally invasive approach. Neuronavigation, intraoperative MRI, CT and ultrasound have increased the ability of the neurosurgeon to perform safe and maximal tumor resection. This may be facilitated by the use of fluorescing agents, which help define the tumor margin, and intraoperative neurophysiological monitoring, which helps identify and protect eloquent brain.

Geoffrey Knight and his contribution to psychosurgery

This paper retraces the fundamental achievements of Geoffrey Knight (1906-1994), a British neurosurgeon and a pioneer in the field of psychosurgery. His career developed in the 1950s and 1960s, when-following the unregulated practice of frontal lobotomies-strong criticism arose in the medical community and in the general public against psychosurgery. Geoffrey Knight's clinical research focused on identifying new, selective targets to limit the side effects of psychosurgery while improving the outcome of patients affected by mental disorders. Following the example of William Beecher Scoville, he initially developed restricted orbital undercutting as a less invasive alternative to standard frontal lobotomy. He then developed stereotactic subcaudate tractotomy, with the use of an original stereotactic device. Knight stressed the importance of the anatomy and neurophysiology of the structures targeted in subcaudate tractotomy, with particular regard to the fibers connecting the anterior cingulate region, the amygdala, the orbitofrontal cortex, and the hypothalamus. Of interest, the role of these white matter connections has been recently recognized in deep brain stimulation for major depression and anorexia nervosa. This is perhaps the most enduring legacy of Knight to the field of psychosurgery. He refined frontal leucotomies by selecting a restricted target at the center of a network that plays a crucial role in controlling mood disorders. He then developed a safe, minimally invasive stereotactic operation to reach this target. His work, well ahead of his time, still represents a valid reference on which to build future clinical experience in the modern era of neuromodulation for psychiatric diseases.