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MGMT promoter methylation is related to the increased sensitivity of tumour tissue to chemotherapy with temozolomide (TMZ) and thus to improved patient survival. However, it is unclear how the extent of MGMT promoter methylation affects outcomes. In our study, a single-centre retrospective study, we explore the impact of MGMT promoter methylation in patients with glioblastoma who were operated upon with 5-ALA. Demographic, clinical and histology data, and survival rates were assessed. A total of 69 patients formed the study group (mean age 53.75 ± 15.51 years old). Positive 5-ALA fluorescence was noted in 79.41%. A higher percentage of MGMT promoter methylation was related to lower preoperative tumour volume (p = 0.003), a lower likelihood of 5-ALA positive fluorescence (p = 0.041) and a larger extent of resection EoR (p = 0.041). A higher MGMT promoter methylation rate was also related to improved progression-free survival (PFS) and overall survival (OS) (p = 0.008 and p = 0.006, respectively), even when adjusted for the extent of resection (p = 0.034 and p = 0.042, respectively). A higher number of adjuvant chemotherapy cycles was also related to longer PFS and OS (p = 0.049 and p = 0.030, respectively). Therefore, this study suggests MGMT promoter methylation should be considered as a continuous variable. It is a prognostic factor that goes beyond sensitivity to chemotherapy treatment, as a higher percentage of methylation is related not only to increased EoR and increased PFS and OS, but also to lower tumour volume at presentation and a lower likelihood of 5-ALA fluorescence intraoperatively.

Safe Trajectory planning for navigation guided biopsy (nBx) of motor eloquent tumours (METs) is important to minimise neurological morbidity. Preliminary clinical data suggest that visualisation of the corticospinal tract (CST) and its relation to the tumour may aid in planning a safe trajectory. In this article we assess the impact of tractography in nBx planning in a simulation-based exercise. This single centre cross-sectional study was performed in March 2021 including 10 patients with METs divided into 2 groups: (1) tractography enhanced group (T-nBx; n = 5; CST merged with volumetric MRI); (2) anatomy-based group (A-nBx; n = 5; volumetric MRI only). A biopsy target was chosen on each tumour. Volunteer neurosurgical trainees had to plan a suitable biopsy trajectory on a Stealth S8® workstation for all patients in a single session. A trajectory safety index (TSI) was devised for each trajectory. Data collection and analysis included a comparison of trajectory planning time, trajectory/lobe changes and TSI. A total of 190 trajectories were analysed based on participation from 19 trainees. Mean trajectory planning time for the entire cohort was 225.1 ± 21.97 s. T-nBx required shorter time for planning (p = 0.01). Mean trajectory changes and lobe changes made per biopsy were 3.28 ± 0.29 and 0.45 ± 0.08, respectively. T-nBx required fewer trajectory/lobe changes (p = 0.01). TSI was better in the presence of tractography than A-nBx (p = 0.04). Neurosurgical experience of trainees had no significant impact on the measured parameters despite adjusted analysis. Irrespective of the level of neurosurgical training, surgical planning of navigation guided biopsy for METs may be achieved in less time with a safer trajectory if tractography imaging is available.

Study Design Retrospective cohort study. Objectives Intraoperative neurophysiological monitoring (IONM) is widely used in spinal neurosurgery, particularly for intramedullary tumours. However, its validity in intradural extramedullary (IDEM) spinal tumours is less clearly defined, this being the focus of this study. Methods We compared outcomes for patients that underwent resection of IDEM tumours with and without IONM between 2010 and 2020. Primary outcomes were postoperative American Spinal Injury Association (ASIA) scores. Other factors assessed were use of intraoperative ultrasound, drain placement, postoperative complications, postoperative Eastern Cooperative Oncology Group (ECOG) score, extent of resection, length of hospital stay, discharge location and recurrence. Results 163 patients were included, 71 patients in the IONM group and 92 in the non-IONM group. No significant differences were noted in baseline demographics. For preoperative ASIA D patients, 44.0% remained ASIA D and 49.9% improved to ASIA E in the IONM group, compared to 39.7% and 30.2% respectively in the non-IONM group. For preoperative ASIA E patients, 50.3% remained ASIA E and 44.0% deteriorated to ASIA D in the IONM group, compared to 30.2% and 39.7% respectively in the non-IONM group (all other patients deteriorated further). Length of inpatient stay was significantly shorter in the IONM group ( P = .043). There were no significant differences in extent of resection, postoperative complications, discharge location or tumour recurrence. Conclusions Research focusing on the use of IONM in IDEM tumour surgery remains scarce. Our study supports the use of IONM during surgical excision of IDEM tumours.

This study aims to review therapeutic strategies in the management of craniospinal tumors in pregnant patients and the factors that may influence the management along with their influence on maternal and fetal outcomes.A retrospective single-center cohort study was performed at a tertiary neurosurgical referral center. Pregnant patients referred to the neuro-oncology multidisciplinary meeting (MDM) with craniospinal tumor were included. Ten-year patient data were collected from hospital records and neuro-oncology MDM outcomes. A systematic review was performed of the available literature as per PRISMA guidelines.Twenty-five patients were identified, with a mean age of 31 years. Of these patients, 88% (n = 22) had cranial lesions and 12% (n = 3) had spinal lesions. Most of the patients had World Health Organization grade I/II tumors. Of the patients, 44% underwent surgery when pregnant, whereas in 40%, this was deferred until after the due date. Of patients, 16% did not require surgical intervention and were followed up with serial imaging in the MDM. The left lateral/park bench position was the preferred position for the spinal and posterior fossa lesions. Systematic review and retrospective data led to proposal of treatment algorithms addressing the therapeutic strategy for management of craniospinal tumors during pregnancy. Factors that may influence maternal and fetal outcomes during management of these tumors were identified, including aggressiveness of the tumor and stage of pregnancy.Craniospinal tumors presenting in pregnancy are challenging. The surgical management needs to be tailored individually and as part of a multidisciplinary team approach. Factors influencing maternal and fetal outcomes are to be considered during management and patient counseling.

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.

Introduction: Penfield’s motor homunculus describes a caricaturised yet useful representation of the map of various body parts on the pre-central cortex. We propose a supplemental map of the clinically represented areas of human body in pre-central cortex and a novel subcortical corticospinal tract map that are accurate and essential for safe surgery in patients with eloquent brain lesions. Materials and methods: A single-institution retrospective cohort study of patients who underwent craniotomy for motor eloquent lesions with intraoperative motor neuromonitoring (cortical and subcortical) between 2015 and 2020 was performed. All positive cortical and subcortical stimulation points were taken into account and cartographic maps were produced to demonstrate cortical and subcortical areas of motor representation and their configuration. A literature review in PubMed was performed. Results: 180 patients (58.4% male, 41.6% female) were included in the study with 81.6% asleep and 18.4% awake craniotomies for motor eloquent lesions (gliomas 80.7%, metastases 13.8%) with intraoperative cortical and subcortical motor mapping. Based on the data, we propose a supplemental clinical cortical and a novel subcortical motor map to the original Penfield’s motor homunculus, including demonstration of localisation of intercostal muscles both in the cortex and subcortex which has not been previously described. Conclusion: The supplementary clinical cortical and novel subcortical motor maps of the homunculus presented here have been derived from a large cohort of patients undergoing direct cortical and subcortical brain mapping. The information will have direct relevance for improving the safety and outcome of patients undergoing resection of motor eloquent brain lesions.

Background: The role played by the non-dominant parietal lobe in motor cognition, attention and spatial awareness networks has potentiated the use of awake surgery. When this is not feasible, asleep monitoring and mapping techniques should be used to achieve an onco-functional balance. Objective: This study aims to assess the feasibility of a dual-strip method to obtain direct cortical stimulation for continuous real-time cortical monitoring and subcortical mapping of motor and visual pathways simultaneously in parietal lobe tumour surgery. Methods: Single-centre prospective study between May’19-November’20 of patients with intrinsic non-dominant parietal-lobe tumours. Two subdural strips were used to simultaneously map and monitor motor and visual pathways. Results: Fifteen patients were included. With regards to motor function, a large proportion of patients had abnormal interhemispheric resting motor threshold ratio (iRMTr) (71.4%), abnormal Cortical Excitability Score (CES) (85.7%), close distance to the corticospinal tract – Lesion-To-Tract Distance (LTD) – 4.2mm, Cavity-To-Tract Distance (CTD) – 7mm and intraoperative subcortical distance - 6.4mm. Concerning visual function, the LTD and CTD for optic radiations (OR) were 0.5mm and 3.4mm, respectively; the mean intensity for positive subcortical stimulation of OR was 12mA±2.3mA and 5/6 patients with deterioration of VEPs>50% had persistent hemianopia and transgression of ORs. 12 patients remained stable, one patient had a de-novo transitory hemiparesis, and two showed improvements in motor symptoms. A higher iRMTr for lower limbs was related with a worse motor outcome (p=0.013) and a longer CTD to OR was directly related with a better visual outcome (p=0.041). At 2 weeks after hospital discharge, all patients were ambulatory at home and all proceeded to have oncological treatment. Conclusion: We propose motor and visual function boundaries for asleep surgery of intrinsic non-dominant parietal tumours. Pre-operative abnormal cortical excitability of the motor cortex, deterioration of the VEP recordings and CTD

Background: Colloid cysts, although benign, may occasionally cause obstructive hydrocephalus and sudden death. Reliable prognostic factors for symptomatic progression have been sought, with heterogenous results. Methods: We conducted a retrospective review of all cases of colloid cysts of the third ventricle managed at our center between 2009 and 2019. Clinical and neuroimaging characteristics were analyzed using logistic regression in relation to symptomatic status and hydrocephalus. The cutoff values for outcome prediction were calculated using the receiver operating characteristic curve analysis. Results: There were 82 patients with colloid cysts, of whom 60 were asymptomatic and 22 symptomatic. None of the asymptomatic patients experienced acute neurologic decline or hydrocephalus during follow-up, whereas half (n = 11) of the symptomatic patients presented with hydrocephalus, 8 of whom had acute hydrocephalus. We found 3 putative candidate risk factors for symptomatic colloid cysts: T1-weighted magnetic resonance imaging hyperintense/mixed signal appearance (P = 0.004), location in risk zone I (P = 0.007), and a volume >236.49 mm 3 (P = 0.007). Cyst diameter and volume/foramen of Monro diameter ratios had a decreasing trend over time among asymptomatic patients, providing new insights into the natural history of the disease. Conclusions: Only a few asymptomatic colloid cysts showed progression requiring surgery, with no acute deterioration or fatal events, whereas the rest remained stable over time, thus supporting a more conservative approach for this group of patients. Higher risk for developing symptomatic colloid cyst was defined by a risk score that included T1-weighted magnetic resonance imaging appearance, risk zone, and colloid cyst volume, aiding the detection of patients at risk of clinical deterioration.

Introduction and objectivesThe novel severe acute respiratory syndrome coronavirus 2 (COVID-19) pandemic has had drastic effects on global healthcare with the UK amongst the countries most severely impacted. The aim of this study was to examine how COVID-19 challenged the neurosurgical delivery of care in a busy tertiary unit serving a socio-economically diverse population.MethodsA prospective single-centre cohort study including all patients referred to the acute neurosurgical service or the subspecialty multidisciplinary teams (MDT) as well as all emergency and elective admissions during COVID-19 (18th March 2020–15th May 2020) compared to pre-COVID-19 (18th of January 2020–17th March 2020). Data on demographics, diagnosis, operation, and treatment recommendation/outcome were collected and analysed.ResultsOverall, there was a reduction in neurosurgical emergency referrals by 33.6% and operations by 55.6% during the course of COVID-19. There was a significant increase in the proportion of emergency operations performed during COVID-19 (75.2% of total,n=155) when compared to pre-COVID-19 (n= 198, 43.7% of total,p< 0.00001). In contrast to other published series, the 30-day perioperative mortality remained low (2.0%) with the majority of post-operative COVID-19-infected patients (n= 13) having underlying medical co-morbidities and/or suffering from post-operative complications.ConclusionThe capacity to safely treat patients requiring urgent or emergency neurosurgical care was maintained at all times. Strategies adopted to enable this included proactively approaching the referrers to maintain lines of communications, incorporating modern technology to run clinics and MDTs, restructuring patient pathways/facilities, and initiating the delivery of NHS care within private sector hospitals. Through this multi-modal approach we were able to minimize service disruptions, the complications, and mortality.

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.

Background Diffuse gliomas have an increased biological aggressiveness across the World Health Organization (WHO) grading system. The implications of glioma grading on the primary motor cortex (M1)-corticospinal tract (CST) excitability is unknown. Objective To assess the excitability of the motor pathway with navigated transcranial magnetic stimulation (nTMS). Methods Retrospective cohort study of patients admitted for surgery with diffuse gliomas within motor eloquent areas. Demographic, clinical, and nTMS-related variables were collected. The Cortical Excitability Score (CES 0 to 2 according to the number of abnormal interhemispheric resting motor threshold (RMT) ratios) was calculated for patients where bilateral upper and lower limb mapping was performed. Results A total of 45 patients were included: 9 patients had a low-grade glioma and 36 patients had a high-grade glioma. The unadjusted analysis revealed an increase in the latency of the motor evoked potential of the lower limb with an increase of the WHO grade (P = .038). The adjusted analysis confirmed this finding (P = .013) and showed a relation between the increase in the WHO and a decreased RMT (P = .037) of the motor evoked responses in the lower limb. When CES was calculated, an increase in the score was related with an increase in the WHO grade (unadjusted analysis-P = .0001; adjusted analysis-P = .001) and in isocitrate dehydrogenase (IDH) wild-type tumors (unadjusted analysis-P = .020). Conclusion An increase in the WHO grading system and IDH wild-type tumors are associated with an abnormal excitability of the motor eloquent areas in patients with diffuse gliomas.

Background Superior medullary velum cerebral cavernous malformations pose a challenge in terms of appropriate microsurgical approach. Safe access to this deep location as well as preservation of surrounding anatomical structures, in particular the superior cerebellar peduncle just lateral to the superior medullary velum and the dentate nuclei, is paramount to achieve a good functional outcome. Methods Cadaveric dissections provide useful knowledge of the normal anatomy while tractography allows a better understanding of the individual anatomy in the presence of a lesion. The medial-tonsillar telovelar approach provides a feasible corridor for accessing superior velum cerebral cavernous malformations without compromising the fibres contained in the superior cerebellar peduncle. The major cerebellar efferents—cerebello-rubral, cerebello-thalamic and cerebello-vestibular tracts—and afferents, anterior spinocerebellar, tectocerebellar and trigeminocerebellar tracts, within the superior cerebellar peduncle are preserved, and the dentate nuclei are not affected. Results and conclusion A retraction-free exposure through this natural posterior fossa corridor allows the patient with the anatomical and functional subtract to make a good functional recovery by minimizing the risk of a superior cerebellar syndrome, ataxia, tremor and dysmetria; decomposition of movement in the ipsilateral extremities, nystagmus and hypotonia; or akinetic mutism, reduced or absent speech with onset within the first post-operative week.

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.

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.

Central nervous system lymphoma (CNSL) represents one of the most aggressive forms of extranodal lymphoma. The gold standard for CNSL diagnosis remains the stereotactic biopsy, with a limited role for cytoreductive surgery that has not been supported by historical data. Our study aims to provide a comprehensive overview of neurosurgery’s role in the diagnosis of systemic relapsed and primary CNSL, with an emphasis on the impact on management and survival. This is a single center retrospective cohort study with data collected between August 2012 and August 2020, including patients referred with a potential diagnosis of CNSL to the local Neuro-oncology Multidisciplinary Team (MDT). The concordance between the MDT outcome and histopathological confirmation was assessed using diagnostic statistics. A Cox regression is used for overall survival (OS) risk factor analysis, and Kaplan–Meier statistics are performed for three prognostic models. The diagnosis of lymphoma is confirmed in all cases of relapsed CNSL, and in all but two patients who underwent neurosurgery. For the relapsed CNSL group, the highest positive predictive value (PPV) is found for an MDT outcome when lymphoma had been considered as single or topmost probable diagnosis. Neuro-oncology MDT has an important role in establishing the diagnosis in CNSL, not only to plan tissue diagnosis but also to stratify the surgical candidates. The MDT outcome based on history and imaging has good predictive value for cases where lymphoma is considered the most probable diagnosis, with the best prediction for cases of relapsed CNSL, questioning the need for invasive tissue diagnosis in the latter group.

Deep-seated brain tumours represent a unique neurosurgical challenge as they are often surrounded by eloquent structures. We describe a minimally invasive technique using tubular retractors and intraoperative neurophysiology monitoring for open biopsy of a deep-seated lesion surrounded by the corticospinal tract. We used preoperative functional mapping with diffusion tensor imaging tractography and navigated transcranial magnetic stimulation to identify a safe surgical corridor. We also used 5-Aminolevulinic Acid induced fluorescence to identify the lesion intraoperatively and optimize tissue samples obtained for histopathological diagnosis. We found the use of these tools improved the safety of surgery and reduced the risk of surgical morbidity.

Objectives: The study aims to evaluate therapeutic strategies in the management of craniospinal tumours in pregnant patients and the factors that influence the management along with their influence on maternal & foetal outcomes. Materials and Methods:A retrospective single-centre cohort study was performed at a tertiary neurosurgical referral centre. Pregnant patients referred to neuro-oncology multidisciplinary meeting (MDM) with craniospinal tumour were included. Ten-year patient data were collected from hospital records and neuro-oncology MDM outcomes. A systematic review was performed on the available literature in PubMed as per PRISMA guidelines. Results:Thirty-three patients were identified with a mean age of 31 years. 91%(n=30) had cranial lesions and 9%(n=3) had spinal lesions. Most of the patients had WHO Grade I/II tumours. 33.3% underwent surgery when pregnant whilst in 24.2% this was deferred until after the due date. 27.2% patients did not require surgical intervention and were followed up with serial imaging in the MDM. Left Lateral/park bench position was the preferred position for the spinal and posterior fossa lesions. Systematic review identified 26 eligible articles. Treatment algorithms are proposed addressing the therapeutic strategy for management of cranio-spinal tumours during pregnancy and the challenges for maternal and foetal outcomes were tabulated. Conclusions:Craniospinal tumours presenting in pregnancy are challenging. The surgical management needs to be tailored individually and as part of a multidisciplinary team approach. Maternal and foetal outcomes are to be considered during patient counselling.

ObjectivesWe aim to demonstrate intraoperative recording of cerebellar to cortical pathways that have not been previously recorded in humans, though imaged.MethodsWe report 2 cases with intraoperative neurophysiologic mapping of cerebellocortical tracts. Direct electrical stimulation of subcortical cerebellum along with recordings of cortical evoked potential and motor muscle recordings was performed during surgery. MR tractography data from healthy participants were used to further illustrate the pathways.ResultsNeurophysiologic recordings showed large waveforms of evoked potentials in bilateral electrodes over premotor/motor cortices on stimulation of the dentate nucleus. EMG recordings showed responses in face and neck muscles on stimulation of the dentate nucleus at the motor threshold. We thus demonstrated first-in-human in vivo neurophysiologic evidence of cerebellum to cortex responses through an uncrossed dentatothalamocortical tract to the motor/premotor cortices.DiscussionThis technique provides a methodology for the direct mapping of the cerebellum and cerebello-cerebral connections. We hypothesize a direct structural connection from the dentate nucleus to the premotor and motor cortices, as well as to ipsilateral hemibody muscles, acting as a fast route of cerebellar output and back up for immediate motor responses. This will further help explain the modulatory effects of the cerebellum on motor, language, and cognitive functions.

Intraoperative neuromonitoring of motor functions experienced a dramatical revolution in the last years thanks to significant advances in anesthesiology procedures and both preoperative and intraoperative mapping techniques. Asleep, awake, and combined intraoperative mapping techniques were responsible for an improvement in the functional outcomes in neurosurgery, providing reliable and reproducible mapping of both projection and association fibers involved in motor control.We report inter-M1 cortico-cortical evoked potential (CCEP) recording during asleep resection of a bilateral parasagittal meningioma with intraoperative neuromonitoring and motor mapping.CCEPs were recorded between both M1 cortices with bipolar stimulations of both supplementary motor areas (10.5-11.5 μV).Here, we provide evidence of intraoperative mapping of commissural fibres involved in motor control in a patient with asleep technique as well as a review of the potential tracts involved in the connectivity underlying the motor function.

Intraoperative neuromonitoring of motor functions experienced a dramatical revolution in the last years due to significant advances in anaesthesiology procedures and both preoperative and intraoperative mapping techniques. Asleep, awake and combined intraoperative mapping techniques were responsible for an improvement in the functional outcomes in neurosurgery providing reliable and reproducible mapping of both projection and association fibres involved in motor control. Here, we provide evidence of intraoperative mapping of commissural fibres involved in motor control in a patient with asleep technique as well as a review of the potential tracts involved in the connectivity underlying the motor function.

Transsulcal minimally invasive parafasicular (TsMIP) approaches to brain tumor resection use tubular retractors to minimize iatrogenic brain injury. Dynamic cortical and subcortical continuous neurophysiological mapping facilitates safer resection of motor-eloquent tumors.To describe a new technique to address the challenge of combining TsMIP with tubular retractors and dynamic subcortical mapping using a single electrified stimulating microdebrider instrument.We adapted the NICO Myriad microdebrider with continuous monopolar stimulation electrification using high-frequency stimulation with the train-of-5 technique. We performed continuous subcortical mapping using this device and compared it with standard dynamic monopolar subcortical mapping using a suction stimulation device. We found no significant difference in recorded stimulation response.Using a single operating instrument that provides synchronous tumor resection and monopolar subcortical mapping with the NICO Brainpath tubular retractor, we observed increased degrees of movement, faster surgical resection times with an enlarged working channel down the retractor, and improved safety because the stimulating probe sits 2 mm deep to the resection window.We show that the adapted device is reliable and provides similar stimulation response as conventional subcortical mapping. We advocate the use of our adapted microdebrider in TsMIP tubular retractor approaches.

Aims Signs and symptoms that develop in people with brain tumours are often attributed to their tumour. The prevalence and management of functional neurological symptoms in brain tumour patients have received little attention. This is surprising because functional neurological symptoms complicate management greatly and misdiagnosis can lead to inappropriate treatment and iatrogenic side-effects. Therefore, we investigated the presentation, diagnosis and management of functional neurological disorders (FND) in patients who had a brain or meningeal tumour. Method A retrospective case review was performed from 2017 - 2021 to identify adult brain tumour patients who developed a functional neurological disorder that caused significant disability necessitating expedited investigations. All patients attended a regional neuro-oncology centre. We recorded type of brain tumour and diagnostic investigations. The onset of functional symptoms was divided into three time windows: before tumour diagnosis, after diagnosis and before treatment or after tumour treatment. A neuropsychological review looked for evidence of previous adverse life events. Therapeutic interventions for functional neurological disorder and their outcomes were documented. The case review was combined with a systematic review of the literature to identify the published presentations of functional neurological disorder in the adult brain tumour population. MEDLINE, EMBASE and PsycINFO databases were searched for studies published between January 1980 and February 2021. Results Six patients (5 female, 1 male) were identified from the case review with a median age of 41 (range 29 - 56) years old. Four patients had non-epileptic attack disorder, which was diagnosed with videotelemetry of habitual attacks. One patient had a functional hemiparesis with normal central motor conduction time. One patient had a functional speech disorder with normal EEG. Half of these patients had functional neurological symptoms prior to surgery/oncological treatment. Five patients (83%) were referred for further neuropsychiatric or psychological evaluation. A history of significant psychological trauma prior to the brain tumour diagnosis was elicited in four (66%) patients. Conclusion Patients with either a brain or meningeal tumour may develop functional neurological symptoms. Our findings suggest the possibility that diagnosis of a brain tumour may precipitate a debilitating functional neurological disorder. The neurobiological basis for functional neurological disorders is being actively investigated. There are suggestions in the literature that some brain diseases increase the risk of developing a functional neurological disorder. Further work is needed to determine whether this is true for patients with brain tumours. Increased awareness of functional neurological disorders will improve management. Withdrawal of unnecessary treatment, such as anticonvulsant drugs, reduces the risk of iatrogenic side effects. Initiation of multi-disciplinary care pathways, e.g. physiotherapy, speech and language therapy and psychological treatments, promotes recovery. Collectively, these interventions improve our patients’ quality of life.

Surgery for meningiomas involving dural venous sinuses is challenging. We describe a case of a peritorcular meningioma involving major venous sinuses, which was removed using a venous sparing approach with the aid of intraoperative ultrasound. We found ultrasound to be a useful adjunct as it enabled us to get real-time information about the location of venous structures, their function and demonstrate dynamic changes in blood flow during surgery.

Background Patient-reported experience measures (PREMs) are a unique measure of experience of patients which can help address the quality of care of the patients. Objective Our aim of the study is to collect quality of care outcomes with our newly navigated transcranial magnetic stimulation patient-reported experience measure (nTMS-PREMs) questionnaire among neurosurgical patients undergoing nTMS. Methods A single-centre prospective nTMS-PREMs 19-item questionnaire study was performed between February 2018 and December 2018 on patient referred for nTMS at our hospital. The Data was analysed using Likert scale, linear and logistic regression using statistical software (STATA 13.0®). Results Fifty patient questionnaires were collected (30 males, 20 females, mean age of 47.6 ± 2.1 years) among which 74% of patients underwent both motor and language mapping with a mean duration of 103.3 ± 5.1 min. An overall positive response was noted from the results of the questionnaire, tiredness and anxiety being the common effects noted. Patients with the left-sided disease appreciated more the conditions provided in our laboratory (Q4, p = 0.040) and increasing age was related to less confidence and trust (Q6, p = 0.038) in the staff performing the exam. Younger patients tolerated nTMS better than older patients (> 65 years). PubMed literature search resulted in no relevant articles on the use of PREMs in nTMS patients. Conclusion nTMS is a well-tolerated non-invasive tool and nTMS-PREMS provides a promising role in identifying the unmet needs of the patients and improving the quality of their care.

Background Protocols for intraoperative language mapping with direct electrical stimulation (DES) often include various language tasks triggering both nouns and verbs in sentences. Such protocols are not readily available for navigated transcranial magnetic stimulation (nTMS), where only single word object naming is generally used. Here, we present the development, norming, and standardization of the verb and noun test for peri-operative testing (VAN-POP) that measures language skills more extensively. Methods The VAN-POP tests noun and verb retrieval in sentence context. Items are marked and balanced for several linguistic factors known to influence word retrieval. The VAN-POP was administered in English, German, and Dutch under conditions that are used for nTMS and DES paradigms. For each language, 30 speakers were tested. Results At least 50 items per task per language were named fluently and reached a high naming agreement. Conclusion The protocol proved to be suitable for pre- and intraoperative language mapping with nTMS and DES.

BackgroundIn 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.MethodsA 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.ResultsA 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.ConclusionsThis 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.

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. 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. 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. 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%). 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.

AIMS There is a gap in supporting patients with sexual relationships and intimacy. The aim of this study is to establish if patients with a brain tumour feel they are able to ask questions and concerns about sex, relationships and intimacy following diagnosis; is there an unmet need and how can this be addressed. METHOD An anonymous survey was sent to patients known to a neuro-oncology team. Questions were in relation to their experiences of sex relationships and intimacy. Patients were asked if they had concerns about changes in their relationships since their diagnosis. They were also asked for their comments on the subject so we can better understand how as a service we can improve to ensure holistic care. RESULTS There are 40 responses. The majority of respondents had concerns about their relationship since diagnosis and that their relationships have changed. 57% were concerned about a physical relationship with a partner/ future partners. 50% agreed their physical relationship had changed. 45% of people agreeing their emotional relationships have changed. 38 out of the 40 people questioned, had not asked their clinical team for advice about sex and relationships. 46% suggested clinicians initiating these conversations. CONCLUSION Sex relationships and intimacy are significant for most adult populations, encompassing connection with their loved ones, self esteem and psychological and emotional well-being. With brain tumour diagnosis this part of people’s lives can hugely impacted. Historically clinicians have found this a difficult subject to discuss. Further work is required to understand the barriers initiating this subject

AIMS Assess the impact of tubular retractor-assisted transsulcal minimal invasive parafascicular approaches(tsMIPS) in the cortical vascularization using indocianin green angiography(ICGA) during removal of deep-seated cerebral tumours. METHOD Single-centre prospective cohort study of patients with deep-seated lesions – distance to nearest sulcus > 10mm - where ICGA was performed. Zeiss FLOW800 Software was used to analyse the following variables - delay time, speed, time to peak and rise time - before and after insertion of the tubular retractor (NICO BrainPath). RESULTS 13 patients were enrolled. 60 regions-of-interest were analysed. The most common pathology was high grade glioma (69%). The average depth of tumours was 34,2mm (23– 45mm) and the time-under-retraction 166mins (45-280 mins). The most common vascular pattern before-after tubular retractor was: increase on the delay time, time to peak and rising time (present in 8 patients) and a decrease on the speed (present in 7 patients). Two patients had a mayor neurological deficit after the surgery. Both had the same flow pattern with an increase on the speed and decrease on the time to peak and rise time, the delay was indifference. CONCLUSION This is the first study assessing the impact of tubular retractor-assisted tsMIPS in cortical vascularization during deep-seated lesion resection. The most common cortical vascular pattern is: an increase on the delay time, time to peak and rising time and a decrease on the speed. The two patients who presented vascular injury shared the same pattern (increase on the speed, decrease on the time to peak and rise time, with indifference delay).

AIMS 5-ALA (Gliolan©) is a valuable surgical tool used predominantly in high grade tumours, which utilises tissue fluorescence to improve the visualisation of the brain-tumour interface. This ensures safe maximal resection, while preserving healthy brain. While Gliolan© use in low grade tumours has previously been reported with variable results, reports of its use and success in the context of SEGA are extremely rare. This report highlights the use of Gliolan© in a patient presenting with a Subependymal Giant Cell Astrocytoma (in a background of tuberous sclerosis), facilitating maximal safe resection and preserving eloquent tissue. METHOD Tumour resection was performed with pre-operative DTI-fiber tracking and mapping. A transsulcal minimal invasive parafascicular approach (tsMIPS) was carried out with assistance of NICO BrainPath© tubular retractor system (60x13.5), neuronaviagtion, Gliolan©, intra-operative neuro monitoring (IONM), and ultrasound guidance RESULTS The tumour was found to have both bright and pale fluorescence in the cystic and solid components respectively. Resection was limited to the soft cystic component only, as the solid tumour component showed anatomical attachment to the subgenual area and the fornix. No fluorescence was perceived at the end of resection. The patient made a good recovery with no post-operative deficits. Histopathology confirmed subependymal giant cell astrocytoma (SEGA, WHO grade I). No adjuvant treatment was required CONCLUSION This reports suggests 5-ALA may be beneficial in the safe resection of SEGAs. Further studies and technological advances in the area of photodynamics, imaging, and intra-operative mapping may be helpful to fully evaluate the efficacy of 5-ALA in SEGAs and other low-grade tumours.

AIMS To describe the methods used to assess and monitor motor function during awake craniotomy surgery for tumour resection. METHOD A service review was carried out over 10 months. Patients with highly motor eloquent lesions – invasion of primary motor cortex or fronto-parietal connections involved in motor cognition – were included. Clinical notes were reviewed and summarised using descriptive analysis. Dexterity and grip strength were measured using 9-hole peg test and handheld dynameter pre/intra and post-operatively. Patient occupation/interests were reported to guide bespoke assessments to trial intra-operatively. RESULTS From April 2021 to January 2022, 13 patients (mean age 39.7 years, 4 female:10 male, 9 low grade:5 high grade gliomas) were included. Mean score 9-hole peg test 22.2sec pre-operatively, 30.6sec post-operatively; handheld dynameter 26.7kg pre-operatively, 18.4kg post-operatively. At discharge 5 of 7 impaired patients demonstrated motor improvement. For motor coordination, motor tasks used frequently included repetitive finger tapping, open/closed hand. Bespoke tasks included texting/writing, playing instruments, and computer games. Movement was closely monitored and verbal feedback given to the neurosurgeons throughout. With video analysis movement comparisons were made. CONCLUSION The role of physiotherapy in awake surgery is evolving to provide movement analysis for complex motor tasks such as upper limb sequencing and dexterity. A combination of standard and bespoke assessments have been trialled and their feasibility within surgery tested. A post-operative deterioration of motor function (power and cognition) is expected after surgery for highly eloquent motor gliomas. However, intraoperative motor assessment for motor cognition allows function preservation and potentiates its recovery.