Current state of global neurosurgery activity amongst European neurosurgeons.

BACKGROUND: The expanding field of global neurosurgery calls for a committed neurosurgical community to advocate for universal access to timely, safe, and affordable neurosurgical care for everyone, everywhere. This study aims to (i) assess the current state of global neurosurgery activity amongst European neurosurgeons and (ii) identify barriers to involvement in global neurosurgery initiatives. METHODS: Cross-sectional study through dissemination of a web-based survey, from September 2019 to January 2020, to collect data from European neurosurgeons at various career stages. Descriptive analysis was conducted on respondent data. RESULTS: Three hundred and ten neurosurgeons from 40 European countries responded. 53.5% regularly follow global neurosurgery developments. 29.4% had travelled abroad with a global neurosurgery collaborative, with 23.2% planning a future trip. Respondents from high income European countries predominantly travelled to Africa (41.6%) or Asia (34.4%), whereas, respondents from middle income European countries frequently traversed Europe (63.2%) and North America (47.4). Cost implications (66.5%) were the most common barrier to global neurosurgery activity, followed by interference with current practice (45.8%), family duties (35.2%), difficulties obtaining humanitarian leave (27.7%) and lack of international partners (27.4%). 86.8% would incorporate a global neurosurgery period within training programmes. CONCLUSIONS: European neurosurgeons are interested in engaging in global neurosurgery partnerships, and several sustainable programmes focused on local capacity building, education and research have been established over the last decade. However, individual and system barriers to engagement persist. We provide insight into these to allow development of tailored mechanisms to overcome such barriers, enabling European neurosurgeons to advocate for the Global Surgery 2030 goals.

Identifying cellular signalling molecules in developmental disorders of the brain: Evidence from focal cortical dysplasia and tuberous sclerosis.

AIMS: We understand little of the pathogenesis of developmental cortical lesions, because we understand little of the diversity of the cell types that contribute to the diseases or how those cells interact. We tested the hypothesis that cellular diversity and cell-cell interactions play an important role in these disorders by investigating the signalling molecules in the commonest cortical malformations that lead to childhood epilepsy, focal cortical dysplasia (FCD) and tuberous sclerosis (TS). METHODS: Transcriptional profiling clustered cases into molecularly distinct groups. Using gene expression data, we identified the secretory signalling molecules in FCD/TS and characterised the cell types expressing these molecules. We developed a functional model using organotypic cultures. RESULTS: We identified 113 up-regulated secretory molecules in FCDIIB/TS. The top 12 differentially expressed genes (DEGs) were validated by immunohistochemistry. This highlighted two molecules, Chitinase 3-like protein 1 (CHI3L1) and C-C motif chemokine ligand 2 (CCL2) (MCP1) that were expressed in a unique population of small cells in close proximity to balloon cells (BC). We then characterised these cells and developed a functional model in organotypic slice cultures. We found that the number of CHI3L1 and CCL2 expressing cells decreased following inhibition of mTOR, the main aberrant signalling pathway in TS and FCD. CONCLUSIONS: Our findings highlight previously uncharacterised small cell populations in FCD and TS which express specific signalling molecules. These findings indicate a new level of diversity and cellular interactions in cortical malformations and provide a generalisable approach to understanding cell-cell interactions and cellular heterogeneity in developmental neuropathology.

Geospatial Mapping of International Neurosurgical Partnerships and Evaluation of Extent of Training and Engagement.

OBJECTIVE: To evaluate the presence, extent, and temporality of transnational neurosurgical partnerships, to understand and inform measures to address neurosurgical deficiencies in low- and middle-income countries (LMICs). METHODS: A Web search was conducted to identify actors from high-income countries (HICs) participating in neurosurgical delivery and/or capacity-building with LMICs from 2010 to 2018. Descriptive data on current neurosurgical partnerships were collected from published case reports, literature reviews, reports from academic institutions, and information on stakeholder Web pages. The level of training and engagement of each partnership was separately graded based on prespecified criteria, in which grade 3 represented partnerships that have most extensive training and engagement, and grade 1, the least extent. Data were analyzed using descriptive statistics and geospatially depicted on ArcMap GIS software. RESULTS: A total of 123 unique HIC-LMIC partnerships were described. Of these partnerships, 85 (69%) are derived from HICs in North America, followed by Europe, with 23 (19%). The most common LMIC partners were from Africa (n = 56, 45%) and Latin America (n = 32, 26%). In addition, most partnerships provided services in pediatric neurosurgery (88%). The most frequent engagement classifications were grade 2 (35%) or 1 (36%). Similarly, for training, the most common classifications were grade 1 (40%) or 2 (30%). CONCLUSIONS: A robust network of HIC-LMIC partnerships exists with varying degrees of engagement and training activities. Several regions are particularly suitable for growth and development. Systematic consolidation and indexing of transnational neurosurgical partnerships aim to enhance resource allocation and present opportunities for future partnership.

The initial experience of InterSurgeon: an online platform to facilitate global neurosurgical partnerships.

OBJECTIVE: Despite general enthusiasm for international collaboration within the organized neurosurgical community, establishing international partnerships remains challenging. The current study analyzes the initial experience of the InterSurgeon website in partnering surgeons from across the world to increase surgical collaboration. METHODS: One year after the launch of the InterSurgeon website, data were collected to quantify the number of website visits, average session duration, total numbers of matches, and number of offers and requests added to the website each month. Additionally, a 15-question survey was designed and distributed to all registered members of the website. RESULTS: There are currently 321 surgeon and institutional members of InterSurgeon representing 69 different countries and all global regions. At the time of the survey there were 277 members, of whom 76 responded to the survey, yielding a response rate of 27.4% (76/277). Twenty-five participants (32.9%) confirmed having either received a match email (12/76, 15.8%) or initiated contact with another user via the website (13/76, 17.1%). As expected, the majority of the collaborations were either between a high-income country (HIC) and a low-income country (LIC) (5/18, 27.8%) or between an HIC and a middle-income country (MIC) (9/18, 50%). Interestingly, there were 2 MIC-to-MIC collaborations (2/18, 11.1%) as well as 1 MIC-to-LIC (1/18, 5.6%) and 1 LIC-to-LIC partnership. At the time of response, 6 (33.3%) of the matches had at least resulted in initial contact via email or telephone. One of the partnerships had involved face-to-face interaction via video conference. A total of 4 respondents had traveled internationally to visit their partner's institution. CONCLUSIONS: Within its first year of launch, the InterSurgeon membership has grown significantly. The partnerships that have already been formed involve not only international visits between HICs and low- to middle-income countries (LMICs), but also telecollaboration and inter-LMIC connections that allow for greater exchange of knowledge and expertise. As membership and site features grow to include other surgical and anesthesia specialties, membership growth and utilization is expected to increase rapidly over time according to social network dynamics.

Determinants of IQ outcome after focal epilepsy surgery in childhood: A longitudinal case-control neuroimaging study.

OBJECTIVE: Intelligence quotient (IQ) outcomes after pediatric epilepsy surgery show significant individual variation. Clinical factors such as seizure cessation or antiepileptic medication discontinuation have been implicated, but do not fully account for the heterogeneity seen. Less is known about the impact of neurobiological factors, such as brain development and resection location. This study examines clinical and neuroimaging factors associated with cognitive outcome after epilepsy surgery in childhood. METHODS: Fifty-two children (28 boys, 24 girls) were evaluated for epilepsy surgery and reassessed on average 7.7 years later. In the intervening time, 13 were treated pharmacologically and 39 underwent focal surgery (17 temporal, 16 extratemporal, six multilobar; mean age at surgery = 14.0 years). Pre- and postsurgical assessments included IQ tests and T1-weighted brain images. Predictors of IQ change were investigated, including voxel-based analyses of resection location, and gray and white matter volume change. RESULTS: Overall modest IQ improvement was seen in children treated surgically, but not in those treated pharmacologically only. Applying a ≥10-point change threshold, 39% of the surgically treated children improved, whereas 10% declined. Clinical factors associated with IQ increases were lower preoperative IQ and longer follow-up duration, whereas seizure and antiepileptic medication cessation were not predictive. Among neuroimaging factors, we observed that left anterior temporal resections impacted negatively on verbal reasoning, linked to full-scale IQ decline. In contrast, gray matter volume change in ipsi- and contralesional hemispheres was positively correlated with IQ change. Voxel-based morphometry identified the gray matter volume change in the contralesional dorsolateral frontal cortex as most strongly associated with IQ improvement. SIGNIFICANCE: We show that a variety of factors are likely to contribute to patterns of postsurgical change in IQ. Neuroimaging results indicate that left anterior temporal resections constrain development of verbal cognition, whereas simultaneously cortical growth after surgical treatment can support improvements in IQ.

Pediatric neurosurgical workforce, access to care, equipment and training needs worldwide.

OBJECTIVE: The presence and capability of existing pediatric neurosurgical care worldwide is unknown. The objective of this study was to solicit the expertise of specialists to quantify the geographic representation of pediatric neurosurgeons, access to specialist care, and equipment and training needs globally. METHODS: A mixed-question survey was sent to surgeon members of several international neurosurgical and general pediatric surgical societies via a web-based platform. Respondents answered questions on 5 categories: surgeon demographics and training, hospital and practice details, surgical workforce and access to neurosurgical care, training and equipment needs, and desire for international collaboration. Responses were anonymized and analyzed using Stata software. RESULTS: A total of 459 surgeons from 76 countries responded. Pediatric neurosurgeons in high-income and upper-middle-income countries underwent formal pediatric training at a greater rate than surgeons in low- and lower-middle-income countries (89.5% vs 54.4%). There are an estimated 2297 pediatric neurosurgeons in practice globally, with 85.6% operating in high-income and upper-middle-income countries. In low- and lower-middle-income countries, roughly 330 pediatric neurosurgeons care for a total child population of 1.2 billion. In low-income countries in Africa, the density of pediatric neurosurgeons is roughly 1 per 30 million children. A higher proportion of patients in low- and lower-middle-income countries must travel > 2 hours to seek emergency neurosurgical care, relative to high-income countries (75.6% vs 33.6%, p < 0.001). Vast basic and essential training and equipment needs exist, particularly low- and lower-middle-income countries within Africa, South America, the Eastern Mediterranean, and South-East Asia. Eighty-nine percent of respondents demonstrated an interest in international collaboration for the purposes of pediatric neurosurgical capacity building. CONCLUSIONS: Wide disparity in the access to pediatric neurosurgical care exists globally. In low- and lower-middle-income countries, wherein there exists the greatest burden of pediatric neurosurgical disease, there is a grossly insufficient presence of capable providers and equipped facilities. Neurosurgeons across income groups and geographic regions share a desire for collaboration and partnership.

Presidential address 2017 William Harkness FRCS October 10th 2017 Denver, Co USA: 2017-annus mirabilis, a global view of neurosurgery for children.

The following presidential address was delivered at the 45th Annual Meeting of the ISPN held in Denver, CO, USA in October 2017.

Pediatric neurosurgical bellwether procedures for infrastructure capacity building in hospitals and healthcare systems worldwide.

PURPOSE: Quantifying the global burden of pediatric neurosurgical disease-and current efforts addressing it-is challenging, particularly in the absence of uniform terminology. We sought to establish bellwether procedures for pediatric neurosurgery, in order to standardize terminology, establish priorities, and facilitate goal-oriented capacity building. METHODS: Members of international pediatric neurosurgical and pediatric surgical societies were surveyed via the Research Electronic Data Capture (REDCap) platform. Among 15 proposed neurosurgical procedures, respondents assigned numerical grades of surgical necessity and selected hospital-level designation within a three-tiered system. A procedure was considered a bellwether if (a) the majority of respondents deemed it necessary for either a primary- or secondary-level hospital and (b) the procedure was graded at or above the 90th percentile on a continuous scale of essentiality. Data were compiled and analyzed using Stata software. RESULTS: Complete responses were obtained from 459 surgeons from 76 countries, the majority of whom practiced in a tertiary referral hospital (88%), with a primarily public patient population (64%). Six bellwether procedures were identified for pediatric neurosurgery: shunt for hydrocephalus, myelomeningocele closure, burr holes, trauma craniotomy, external ventricular drain (EVD) insertion, and cerebral abscess evacuation. Few differences in bellwether criteria designations were observed among respondents from different World Health Organization regions and World Bank income groups. CONCLUSIONS: The six bellwether procedures identified can be used as markers of infrastructure capacity at various hospital levels, hence allowing targeted neurosurgical capacity-building in low-resource settings in order to avert disability and death from childhood neurosurgical disease.

Seizure and cognitive outcomes after resection of glioneuronal tumors in children.

OBJECTIVE: Glioneuronal tumors (GNTs) are well-recognized causes of chronic drug-resistant focal epilepsy in children. Our practice involves an initial period of radiological surveillance and antiepileptic medications, with surgery being reserved for those with radiological progression or refractory seizures. We planned to analyze the group of patients with low-grade GNTs, aiming to identify factors affecting seizure and cognitive outcomes. METHODS: We retrospectively reviewed the medical records of 150 children presenting to Great Ormond Street Hospital with seizures secondary to GNTs. Analysis of clinical, neuroimaging, neuropsychological, and surgical factors was performed to determine predictors of outcome. Seizure outcome at final follow-up was classified as either seizure-free (group A) or not seizure-free (group B) for patients with at least 12-months follow-up postsurgery. Full-scale intelligence quotient (FSIQ) was used as a measure of cognitive outcome. RESULTS: Eighty-six males and 64 females were identified. Median presurgical FSIQ was 81. One hundred twenty-one patients (80.5%) underwent surgery. Median follow-up after surgery was 2 years, with 92 patients (76%) having at least 12 months of follow-up after surgery. Seventy-four patients (80%) were seizure-free, and 18 (20%) continued to have seizures. Radiologically demonstrated complete tumor resection was associated with higher rates of seizure freedom (P = .026). Higher presurgical FSIQ was related to shorter epilepsy duration until surgery (P = .012) and to older age at seizure onset (P = .043). SIGNIFICANCE: A high proportion of children who present with epilepsy and GNTs go on to have surgical tumor resection with excellent postoperative seizure control. Complete resection is associated with a higher chance of seizure freedom. Higher presurgical cognitive functioning is associated with shorter duration of epilepsy prior to surgery and with older age at seizure onset. Given the high rate of eventual surgery, early surgical intervention should be considered in children with continuing seizures associated with GNTs.

Comprehensive molecular characterisation of epilepsy-associated glioneuronal tumours.

Glioneuronal tumours are an important cause of treatment-resistant epilepsy. Subtypes of tumour are often poorly discriminated by histological features and may be difficult to diagnose due to a lack of robust diagnostic tools. This is illustrated by marked variability in the reported frequencies across different epilepsy surgical series. To address this, we used DNA methylation arrays and RNA sequencing to assay the methylation and expression profiles within a large cohort of glioneuronal tumours. By adopting a class discovery approach, we were able to identify two distinct groups of glioneuronal tumour, which only partially corresponded to the existing histological classification. Furthermore, by additional molecular analyses, we were able to identify pathogenic mutations in BRAF and FGFR1, specific to each group, in a high proportion of cases. Finally, by interrogating our expression data, we were able to show that each molecular group possessed expression phenotypes suggesting different cellular differentiation: astrocytic in one group and oligodendroglial in the second. Informed by this, we were able to identify CCND1, CSPG4, and PDGFRA as immunohistochemical targets which could distinguish between molecular groups. Our data suggest that the current histological classification of glioneuronal tumours does not adequately represent their underlying biology. Instead, we show that there are two molecular groups within glioneuronal tumours. The first of these displays astrocytic differentiation and is driven by BRAF mutations, while the second displays oligodendroglial differentiation and is driven by FGFR1 mutations.

Factors affecting seizure outcome after epilepsy surgery: an observational series.

IMPORTANCE: Surgical treatment can bring seizure remission in people with focal epilepsy but requires careful selection of candidates. OBJECTIVES: To determine which preoperative factors are associated with postoperative seizure outcome. DESIGN: We audited seizure outcome of 693 adults who had resective epilepsy surgery between 1990 and 2010 and used survival analysis to detect preoperatively identifiable risk factors of poor seizure outcome. RESULTS: Seven factors were significantly associated with increased probability of recurrence of seizures with impaired awareness postsurgery: MRI findings (eg, HR adjusted for other variables in the model 2.5; 95% CI 1.6 to 3.8 for normal MRI compared with hippocampal sclerosis), a history of secondarily generalised convulsive seizures (2.3; 95% CI 1.7 to 3.0 for these seizures in the previous year vs never), psychiatric history (1.3; 95% CI 1.1 to 1.7), learning disability (1.8; 95% CI 1.2 to 2.6) and extratemporal (vs temporal) surgery (1.4; 95% CI 1.02, 2.04). People with an older onset of epilepsy had a higher probability of seizure recurrence (1.01; 95% CI 1.00, 1.02) as did those who had used more antiepileptic drugs (1.05; 95% CI 1.01 to 1.09). Combinations of variables associated with seizure recurrence gave overall low probabilities of 5-year seizure freedom (eg, a normal MRI and convulsive seizures in the previous year has a probability of seizure freedom at 5 years of approximately 0.19). CONCLUSIONS AND RELEVANCE: Readily identified clinical features and investigations are associated with reduced probability of good outcome and need consideration when planning presurgical evaluation.

Technical aspects of pediatric epilepsy surgery: Report of a multicenter, multinational web-based survey by the ILAE Task Force on Pediatric Epilepsy Surgery.

Surgical techniques may vary extensively between centers. We report on a web-based survey aimed at evaluating the current technical approaches in different centers around the world performing epilepsy surgery in children. The intention of the survey was to establish technical standards. A request was made to 88 centers to complete a web-based survey comprising 51 questions. There were 14 questions related to general issues, 13 questions investigating the different technical aspects for children undergoing epilepsy surgery, and 24 questions investigating surgical strategies in pediatric epilepsy surgery. Fifty-two centers covering a wide geographic representation completed the questionnaire. The median number of resective procedures per center per year was 47. Some important technical practices appeared (>80% of the responses) such as the use of prophylactic antibiotics (98%), the use of high-speed drills for bone opening (88%), nonresorbable material for bone flap closure (85%), head fixation (90%), use of the surgical microscope (100%), and of free bone flaps. Other questions, such as the use of drains, electrocorticography (ECoG) and preoperative withdrawal of valproate, led to mixed, inconclusive results. Complications were noted in 3.8% of the patients submitted to cortical resection, 9.9% hemispheric surgery, 5% callosotomy, 1.8% depth electrode implantation, 5.9% subdural grids implantation, 11.9% hypothalamic hamartoma resection, 0.9% vagus nerve stimulation (VNS), and 0.5% deep brain stimulation. There were no major differences across regions or countries in any of the subitems above. The present data offer the first overview of the technical aspects of pediatric epilepsy surgery worldwide. Surprisingly, there seem to be more similarities than differences. That aside many of the evaluated issues should be examined by adequately designed multicenter randomized controlled trials (RCTs). Further knowledge on these technical issues might lead to increased standardization and lower costs in the future, as well as definitive practice guidelines.

Outcome following multiple subpial transection in Landau-Kleffner syndrome and related regression.

OBJECTIVE: To determine whether multiple subpial transection in the posterior temporal lobe has an impact on long-term outcome in children who have drug-resistant Landau-Kleffner syndrome (LKS) or other "electrical status epilepticus during sleep" (ESES)-related regression. Given the wide variability in outcomes reported in the literature, a secondary aim was to explore predictors of outcome. METHODS: The current study includes a surgery group (n = 14) comprising patients who underwent multiple subpial transection of the posterior temporal lobe and a nonsurgery comparison group (n = 21) comprising patients who underwent presurgical investigations for the procedure, but who did not undergo surgery. Outcomes were assessed utilizing clinical note review as well as direct assessment and questionnaires. RESULTS: The distribution of nonclassical cases was comparable between groups. There were some differences between the surgery and nonsurgery groups at presurgical investigation including laterality of discharges, level of language impairment, and age; therefore, follow-up analyses focused on change over time and predictors of outcome. There were no statistically significant differences between the groups in language, nonverbal ability, adaptive behavior, or quality of life at follow-up. There was no difference in the proportion of patients showing improvement or deterioration in language category over time for either group. Continuing seizures and an earlier age of onset were most predictive of poorer quality of life at long-term follow-up (F2,23 = 26.2, p = <0.001, R(2) = 0.714). SIGNIFICANCE: Both surgery and nonsurgery groups had similar proportions of classic LKS and ESES-related regression. Because no significant differences were found in the changes observed from baseline to follow-up between the two groups, it is argued that there is insufficient evidence to suggest that multiple subpial transection provides additional benefits over and above the mixed recovery often seen in LKS and related regressive epilepsies.

Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome.

The temporal lobes play a prominent role in declarative memory function, including episodic memory (memory for events) and semantic memory (memory for facts and concepts). Surgical resection for medication-resistant and well-localized temporal lobe epilepsy has good prognosis for seizure freedom, but is linked to memory difficulties in adults, especially when the removal is on the left side. Children may benefit most from surgery, because brain plasticity may facilitate post-surgical reorganization, and seizure cessation may promote cognitive development. However, the long-term impact of this intervention in children is not known. We examined memory function in 53 children (25 males, 28 females) who were evaluated for epilepsy surgery: 42 underwent unilateral temporal lobe resections (25 left, 17 right, mean age at surgery 13.8 years), 11 were treated only pharmacologically. Average follow-up was 9 years (range 5-15). Post-surgical change in visual and verbal episodic memory, and semantic memory at follow-up were examined. Pre- and post-surgical T1-weighted MRI brain scans were analysed to extract hippocampal and resection volumes, and evaluate post-surgical temporal lobe integrity. Language lateralization indices were derived from functional magnetic resonance imaging. There were no significant pre- to postoperative decrements in memory associated with surgery. In contrast, gains in verbal episodic memory were seen after right temporal lobe surgery, and visual episodic memory improved after left temporal lobe surgery, indicating a functional release in the unoperated temporal lobe after seizure reduction or cessation. Pre- to post-surgical change in memory function was not associated with any indices of brain structure derived from MRI. However, better verbal memory at follow-up was linked to greater post-surgical residual hippocampal volumes, most robustly in left surgical participants. Better semantic memory at follow-up was associated with smaller resection volumes and greater temporal pole integrity after left temporal surgery. Results were independent of post-surgical intellectual function and language lateralization. Our findings indicate post-surgical, hemisphere-dependent material-specific improvement in memory functions in the intact temporal lobe. However, outcome was linked to the anatomical integrity of the temporal lobe memory system, indicating that compensatory mechanisms are constrained by the amount of tissue which remains in the operated temporal lobe. Careful tailoring of resections for children undergoing epilepsy surgery may enhance long-term memory outcome.

COL4A1 mutations should not be a contraindication for epilepsy surgery.

PURPOSE: We describe the first case in the literature of complication-free epilepsy surgery in a paediatric patient with collagen type IV alpha 1 (COL4A1) mutation. METHODS: This is a case report. RESULTS: COL4A1 mutations disrupt the integrity of vascular basement membranes, so predisposing to a broad spectrum of disorders including periventricular leucomalacia, haemorrhagic stroke, aneurysm formation, epilepsy and developmental delay. Intracranial haemorrhage is reported and may be recurrent or associated with trauma and anticoagulant therapy. Children have an increased risk of stroke with general anaesthesia. A 6-year-old girl, COL4A1 mutation positive, had drug-resistant epilepsy, cerebral palsy and developmental delay. Following presurgical evaluation, she was a candidate for corpus callosotomy. Previous general anaesthesia had been uncomplicated. Preoperative full blood count and coagulation studies were normal. Perioperatively, normotension was maintained, and anticoagulation was avoided. A complete corpus callosotomy was performed with no intracranial haemorrhage or other perioperative complications. CONCLUSION: Although there is an increased risk of intracranial haemorrhages in COL4A1 patients, this is not clearly quantifiable. There are minimal data in the literature on the subject. COL4A1 mutations should not be a contraindication for presurgical evaluation. Each patient should be individually evaluated and assessed, risks and benefits were carefully weighed, and informed decisions were reached after thorough discussions with patients and families.