Fibre orientation atlas guided rapid segmentation of white matter tracts.

Fibre tract delineation from diffusion magnetic resonance imaging (MRI) is a valuable clinical tool for neurosurgical planning and navigation, as well as in research neuroimaging pipelines. Several popular methods are used for this task, each with different strengths and weaknesses making them more or less suited to different contexts. For neurosurgical imaging, priorities include ease of use, computational efficiency, robustness to pathology and ability to generalise to new tracts of interest. Many existing methods use streamline tractography, which may require expert neuroimaging operators for setting parameters and delineating anatomical regions of interest, or suffer from as a lack of generalisability to clinical scans involving deforming tumours and other pathologies. More recently, data-driven approaches including deep-learning segmentation models and streamline clustering methods have improved reproducibility and automation, although they can require large amounts of training data and/or computationally intensive image processing at the point of application. We describe an atlas-based direct tract mapping technique called 'tractfinder', utilising tract-specific location and orientation priors. Our aim was to develop a clinically practical method avoiding streamline tractography at the point of application while utilising prior anatomical knowledge derived from only 10-20 training samples. Requiring few training samples allows emphasis to be placed on producing high quality, neuro-anatomically accurate training data, and enables rapid adaptation to new tracts of interest. Avoiding streamline tractography at the point of application reduces computational time, false positives and vulnerabilities to pathology such as tumour deformations or oedema. Carefully filtered training streamlines and track orientation distribution mapping are used to construct tract specific orientation and spatial probability atlases in standard space. Atlases are then transformed to target subject space using affine registration and compared with the subject's voxel-wise fibre orientation distribution data using a mathematical measure of distribution overlap, resulting in a map of the tract's likely spatial distribution. This work includes extensive performance evaluation and comparison with benchmark techniques, including streamline tractography and the deep-learning method TractSeg, in two publicly available healthy diffusion MRI datasets (from TractoInferno and the Human Connectome Project) in addition to a clinical dataset comprising paediatric and adult brain tumour scans. Tract segmentation results display high agreement with established techniques while requiring less than 3 min on average when applied to a new subject. Results also display higher robustness than compared methods when faced with clinical scans featuring brain tumours and resections. As well as describing and evaluating a novel proposed tract delineation technique, this work continues the discussion on the challenges surrounding the white matter segmentation task, including issues of anatomical definitions and the use of quantitative segmentation comparison metrics.

Decision making for health-related research outcomes that alter diagnosis: A model from paediatric brain tumours.

AIMS: The question of how to handle clinically actionable outcomes from retrospective research studies is poorly explored. In neuropathology, this problem is exacerbated by ongoing refinement in tumour classification. We sought to establish a disclosure threshold for potential revised diagnoses as determined by the neuro-oncology speciality. METHODS: As part of a previous research study, the diagnoses of 73 archival paediatric brain tumour samples were reclassified according to the WHO 2016 guidelines. To determine the disclosure threshold and clinical actionability of pathology-related findings, we conducted a result-evaluation approach within the ethical framework of BRAIN UK using a surrogate clinical multidisciplinary team (MDT) of neuro-oncology specialists. RESULTS: The MDT identified key determinants impacting decision-making, including anticipated changes to patient management, time elapsed since initial diagnosis, likelihood of the patient being alive and absence of additional samples since cohort inception. Ultimately, none of our research findings were considered clinically actionable, largely due to the cohort's historic archival and high-risk nature. From this experience, we developed a decision-making framework to determine if research findings indicating a change in diagnosis require reporting to the relevant clinical teams. CONCLUSIONS: Ethical issues relating to the use of archival tissue for research and the potential to identify actionable findings must be carefully considered. We have established a structured framework to assess the actionability of research data relating to patient diagnosis. While our specific findings are most applicable to the pathology of poor prognostic brain tumour groups in children, the model can be adapted to a range of disease settings, for example, other diseases where research is dependent on retrospective tissue cohorts, and research findings may have implications for patients and families, such as other tumour types, epilepsy-related pathology, genetic disorders and degenerative diseases.

Transcallosal approach and post-operative subdural collections: 12-year paediatric neurosurgery tertiary centre experience.

INTRODUCTION: Following transcallosal surgery for tumour resection, the formation of convexity or interhemispheric subdural cerebrospinal fluid collections may lead to clinical deterioration and may influence decision-making with regards to additional interventions. The aim of this study was to determine the incidence, risk factors, and management of subdural collections following the transcallosal approach in a paediatric cohort. METHODS: A retrospective case note and radiological review of all children who underwent transcallosal surgery for intraventricular and thalamic tumours was carried out covering a 12-year period (2012-2023) in a single-centre tertiary paediatric neurosurgery unit. Parameters including demographics and clinical information including lesion location, pathology, extent of resection, need for and type of shunt required, as well as depth, laterality, and location of the collection were analysed prior to shunting, and at approximately 3 weeks, 3 months, and latest follow-up available post-operatively in order to further elucidate the natural history of these subdural collections and their clinical significance. RESULTS: Sixty-four cases satisfied the inclusion criteria of transcallosal surgery for tumour resection; 13 did not have adequate post-operative imaging and were excluded. Of the remaining 51 cases, there were 32 children (63%) with post-operative CSF subdural collections, of which 59% were ipsilateral, with the remainder showing bilateral distribution. The overall shunt insertion rate was 25.5% (12 ventriculoperitoneal and 1 subdural-peritoneal shunt) at 3 months, with a mean time to shunting of 19 days post-operatively. Children who developed post-operative subdural collections had a higher rate of shunting, at 37.5%, compared to 5.2% in those who did not. Pre- and post-operative hydrocephalus and subtotal resection were identified as risk factors for development of subdural collections post-operatively. Subdural collections showed a natural course of reduction and regression over follow-up, with the exception of 3 children where they persisted or increased over time; although none of these required shunting. Those children who underwent shunt insertion showed greater regression in the size of the subdural collection over time compared to the non-shunted group. CONCLUSION: In this paediatric cohort, 25.5 % of children required insertion of a shunt by 3 months following transcallosal surgery. Pre- and post-operative hydrocephalus and subtotal tumour resection were risk factors for development of subdural collections post-operatively.

Safety and effectiveness of Evicel® fibrin sealant as an adjunct to sutured dural repair in children undergoing cranial neurosurgery.

PURPOSE: Cerebrospinal fluid (CSF) leakage is a challenging complication of intradural cranial surgery, and children are particularly at risk. The use of dural sealants confers protection in adults, but pediatric studies are scarce. We evaluated the safety and efficacy of Evicel® fibrin sealant as an adjunct to primary dural suturing in children undergoing cranial surgery. METHODS: A multicenter trial prospectively enrolled pediatric subjects (< 18 years) undergoing cranial neurosurgery who, upon completion of primary sutured dural repair, experienced CSF leakage. As agreed by the EMA Evicel® Pediatric Investigation Plan, 40 subjects were intra-operatively randomized 2:1 to Evicel® or additional sutures ('Sutures'). Data analysis was descriptive. The efficacy endpoint was treatment success rate, with success defined as intra-operative watertight closure after provocative Valsalva maneuver (primary endpoint). Safety endpoints were postoperative CSF leakage (incisional CSF leakage, pseudomeningocele or both) and surgical site complications (secondary endpoints). RESULTS: Forty subjects (0.6-17 years) were randomized to Evicel® (N = 25) or Sutures (N = 15) (intention-to-treat). Intracranial tumor was the most common indication and procedures were mostly supratentorial craniotomies. Success rates were 92.0% for Evicel® and 33.3% for Sutures, with a 2.76 estimated ratio of success rates (Farrington-Manning 95% CI [1.53, 6.16]). Sensitivity analyses in per-protocol and safety sets showed similar results. Despite a higher rescue treatment rate, the frequencies of postoperative CSF leakage and wound complications were higher for Sutures than for Evicel®. CONCLUSION: This small-scale prospective study shows Evicel® treatment to be safe and effective as an adjunct to primary sutured dura mater closure in a pediatric population. Compared to additional sutures, Evicel® was associated with reduced postoperative CSF leakage and surgical site complications. (Trial registration: The trial was registered as NCT02309645 and EudraCT 2013-003558-26).

Selective dorsal rhizotomy in non-ambulant children with cerebral palsy: a multi-center prospective study.

PURPOSE: Assess the effects of selective dorsal rhizotomy (SDR) on motor function and quality of life in children with a Gross Motor Function Classification System (GMFCS) level of IV or V (non-ambulatory). METHODS: This is a prospective, observational study in three tertiary neurosurgery units in England, UK, performing SDR on children aged 3-18 with spastic diplegic cerebral palsy, and a GMFCS level of IV or V, between 2012 and 2019. The primary outcome measure was the change in the 66-item Gross Motor Function Measure (GMFM-66) from baseline to 24 months after SDR, using a linear mixed effects model. Secondary outcomes included spasticity, bladder function, quality of life, and pain scores. RESULTS: Between 2012 and 2019, 144 children who satisfied these inclusion criteria underwent SDR. The mean age was 8.2 years. Fifty-two percent were female. Mean GMFM-66 score was available in 77 patients (53.5%) and in 39 patients (27.1%) at 24 months after SDR. The mean increase between baseline and 24 months post-SDR was 2.4 units (95% CI 1.7-3.1, p < 0.001, annual change 1.2 units). Of the 67 patients with a GMFM-66 measurement available, a documented increase in gross motor function was seen in 77.6% (n = 52). Of 101 patients with spasticity data available, mean Ashworth scale decreased after surgery (2.74 to 0.30). Of patients' pain scores, 60.7% (n = 34) improved, and 96.4% (n = 56) of patients' pain scores remained the same or improved. Bladder function improved in 30.9% of patients. CONCLUSIONS: SDR improved gross motor function and reduced pain in most patients at 24 months after surgery, although the improvement is less pronounced than in children with GMFCS levels II and III. SDR should be considered in non-ambulant patients.

Experience in endoscope choice for neuroendoscopic lavage for intraventricular hemorrhage of prematurity: a systematic review.

OBJECTIVE: Intraventricular hemorrhage (IVH) of prematurity occurs in 20-38% of infants born < 28 weeks gestational age and 15% of infants born in 28-32 weeks gestational age. Treatment has evolved from conservative management and CSF diversion of temporizing and shunting procedures to include strategies aimed at primarily clearing intraventricular blood products. Neuroendoscopic lavage (NEL) aims to decrease the intraventricular blood burden under the same anesthetic as temporizing CSF diversion measures in cases of hydrocephalus from IVH of prematurity. Given the variety of neuroendoscopes, we sought to review the literature and practical considerations to help guide neuroendoscope selection when planning NEL. METHODS: We conducted a systematic review of the literature on neuroendoscopic lavage in IVH of prematurity to examine data on the choice of neuroendoscope and outcomes regarding shunt rate. We then collected manufacturer data on neuroendoscopic devices, including inflow and outflow mechanisms, working channel specifications, and tools compatible with the working channel. We paired this information with the advantages and disadvantages reported in the literature and observations from the experiences of pediatric neurosurgeons from several institutions to provide a pragmatic evaluation of international clinical experience with each neuroendoscope in NEL. RESULTS: Eight studies were identified; four neuroendoscopes have been used for NEL as reported in the literature. These include the Karl Storz Flexible Neuroendoscope, LOTTA® system, GAAB system, and Aesculap MINOP® system. The LOTTA® and MINOP® systems were similar in setup and instrument options. Positive neuroendoscope features for NEL include increased degrees of visualization, better visualization with the evolution of light and camera sources, the ability to sterilize with autoclave processes, balanced inflow and outflow mechanisms via separate channels, and a working channel. Neuroendoscope disadvantages for NEL may include special sterilization requirements, large outer diameter, and limitations in working channels. CONCLUSIONS: A neuroendoscope integrating continuous irrigation, characterized by measured inflow and outflow via separate channels and multiple associated instruments, appears to be the most commonly used technology in the literature. As neuroendoscopes evolve, maximizing clear visualization, adequate inflow, measured outflow, and large enough working channels for paired instrumentation while minimizing the footprint of the outer diameter will be most advantageous when applied for NEL in premature infants.

Molecular subgroup of medulloblastoma: evaluation of contribution to CSF diversion following tumour resection.

INTRODUCTION: Medulloblastoma is the commonest malignant brain tumour in children. Pre-operative hydrocephalus is present in up to 90% of these patients at presentation. Following posterior fossa surgery, despite resolution of fourth ventricular obstruction, a proportion of these children will still require cerebrospinal fluid (CSF) diversion for management of persistent or new hydrocephalus. Various scoring systems have been developed to predict the risk for CSF diversion following posterior fossa surgery. However, no accurate tool exists regarding which pathological subset or group of medulloblastoma patients will require a shunt post-operatively. In this study we investigated the impact of molecular subgroup of medulloblastoma on shunt dependency post-operatively in paediatric patients. METHODS: We undertook a retrospective multi-centre study of children with medulloblastoma who underwent tumour resection. Those with available molecular subgroup were identified. Demographic data and clinical parameters including age, sex, presence of pre-operative hydrocephalus, extent of surgical resection, evidence of metastasis/leptomeningeal disease and need for CSF diversion post-operatively were further analysed. RESULTS: Sixty-nine children with medulloblastoma with available molecular data were identified during the study period with male to female ratio of 1.5:1 (42M:27F). Twelve patients (17.4%) belonged to SHH, 10 (14.5%) Wnt, 19 (27.5%) Group 3 and 15 (21.7%) Group 4; 13 (18.8%) were non-specified Group 3 or 4. A total of 18 (26%) patients had evidence of leptomeningeal disease at presentation (20% of Wnt, 42% of Group 3, 33% of group 4, 23% of group 3/4, and 0% of SHH). Fifteen patients (22%) underwent post-operative ventriculoperitoneal (VP) shunt insertion. No patient in the Wnt group required ventriculoperitoneal (VP) shunt post-operatively in this cohort. Need for shunt was associated with pre-operative hydrocephalus, leptomeningeal disease, with molecular group 3 or 4 demonstrating higher rate of leptomeningeal disease, and pre-operative hydrocephalus. Age, extent of resection and pre-operative EVD were not associated with need for shunt in this cohort. Regression analysis identified only pre-operative hydrocephalus and leptomeningeal disease as independent predictors of need for shunt post-resection in this cohort. CONCLUSION: All patients requiring permanent post-operative VP shunt belonged to non-Wnt groups, particularly group 3 and 4. Although medulloblastoma subgroup does not independently predict need for post-operative shunt, presence of leptomeningeal disease and pre-operative hydrocephalus, and their higher prevalence in group 3 and 4, likely account for observed higher rate of shunting in these groups.

Comparison of endoscopic sinus sampling versus intracranial sampling for microbiological diagnosis of intracranial infection in children: a case series and literature review.

INTRODUCTION: Intracranial infection is often associated with contiguous sinus infection, with Streptococcus intermedius being the most common pathogen. Microbiological assessment is possible via sinus or intracranial sampling. While a sinus approach is minimally invasive, it is not clear whether this yields definitive microbiological diagnosis leading to optimized antimicrobial therapy and avoidance of intracranial surgery. METHODS: A retrospective review of a prospectively collected electronic departmental database identified patients between 2019 and 2022. Further demographic and microbiological information was obtained from electronic patient records and laboratory management systems. RESULTS: Thirty-one patients were identified with intracranial subdural and/or epidural empyema and concurrent sinus involvement during the 3-year study period. The median age of onset was 10 years with a slight male predominance (55%). All patients had intracranial sampling with 15 patients undergoing sinus sampling in addition. Only 1 patient (7%) demonstrated identical organism(s) grown from both samples. Streptococcus intermedius was the most common pathogen in intracranial samples. Thirteen patients (42%) had mixed organisms from their intracranial cultures and 57% of samples undergoing bacterial PCR identified additional organisms, predominantly anaerobes. Sinus samples had a significant addition of nasal flora and Staphylococcus aureus which was rarely grown from intracranial samples. Of concern, 7/14 (50%) of sinus samples did not identify the main intracranial pathogen diagnosed on intracranial culture and additional PCR. Literature review identified 21 studies where sinus drainage was used to treat intracranial empyemas, with only 6 authors reporting concurrent microbiology results. This confirmed our cohort to be the largest comparative study in the current literature. No center has observed a greater than 50% concordance in microbiological diagnoses. CONCLUSION: Endoscopic sinus surgery may have therapeutic benefit, but it is not an appropriate approach for microbiological diagnosis in pediatric subdural empyemas. High rates of contaminating nasal flora can lead to misdiagnosis and inappropriate treatment. Routine addition of 16S rRNA PCR to intracranial samples is recommended.

MRI Radiogenomics of Pediatric Medulloblastoma: A Multicenter Study.

Background Radiogenomics of pediatric medulloblastoma (MB) offers an opportunity for MB risk stratification, which may aid therapeutic decision making, family counseling, and selection of patient groups suitable for targeted genetic analysis. Purpose To develop machine learning strategies that identify the four clinically significant MB molecular subgroups. Materials and Methods In this retrospective study, consecutive pediatric patients with newly diagnosed MB at MRI at 12 international pediatric sites between July 1997 and May 2020 were identified. There were 1800 features extracted from T2- and contrast-enhanced T1-weighted preoperative MRI scans. A two-stage sequential classifier was designed-one that first identifies non-wingless (WNT) and non-sonic hedgehog (SHH) MB and then differentiates therapeutically relevant WNT from SHH. Further, a classifier that distinguishes high-risk group 3 from group 4 MB was developed. An independent, binary subgroup analysis was conducted to uncover radiomics features unique to infantile versus childhood SHH subgroups. The best-performing models from six candidate classifiers were selected, and performance was measured on holdout test sets. CIs were obtained by bootstrapping the test sets for 2000 random samples. Model accuracy score was compared with the no-information rate using the Wald test. Results The study cohort comprised 263 patients (mean age ± SD at diagnosis, 87 months ± 60; 166 boys). A two-stage classifier outperformed a single-stage multiclass classifier. The combined, sequential classifier achieved a microaveraged F1 score of 88% and a binary F1 score of 95% specifically for WNT. A group 3 versus group 4 classifier achieved an area under the receiver operating characteristic curve of 98%. Of the Image Biomarker Standardization Initiative features, texture and first-order intensity features were most contributory across the molecular subgroups. Conclusion An MRI-based machine learning decision path allowed identification of the four clinically relevant molecular pediatric medulloblastoma subgroups. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Chaudhary and Bapuraj in this issue.

Tractographic and Microstructural Analysis of the Dentato-Rubro-Thalamo-Cortical Tracts in Children Using Diffusion MRI.

The dentato-rubro-thalamo-cortical tract (DRTC) is the main outflow pathway of the cerebellum, contributing to a finely balanced corticocerebellar loop involved in cognitive and sensorimotor functions. Damage to the DRTC has been implicated in cerebellar mutism syndrome seen in up to 25% of children after cerebellar tumor resection. Multi-shell diffusion MRI (dMRI) combined with quantitative constrained spherical deconvolution tractography and multi-compartment spherical mean technique modeling was used to explore the frontocerebellar connections and microstructural signature of the DRTC in 30 healthy children. The highest density of DRTC connections were to the precentral (M1) and superior frontal gyri (F1), and from cerebellar lobules I-IV and IX. The first evidence of a topographic organization of anterograde projections to the frontal cortex at the level of the superior cerebellar peduncle (SCP) is demonstrated, with streamlines terminating in F1 lying dorsomedially in the SCP compared to those terminating in M1. The orientation dispersion entropy of DRTC regions appears to exhibit greater contrast than that shown by fractional anisotropy. Analysis of a separate reproducibility cohort demonstrates good consistency in the dMRI metrics described. These novel anatomical insights into this well-studied pathway may prove to be of clinical relevance in the surgical resection of cerebellar tumors.

Paediatric neurosurgical implications of a ribosomopathy: illustrative case and literature review.

Ribosomopathies are rare, recently defined entities. One of these, Labrune syndrome, is recognisable radiologically by its distinctive triad of leukoencephalopathy, intracranial calcifications and cysts (LCC). These cysts may have neurosurgical implications at different ages because of their progressive expansion and local mass effect. The aetiology of LCC is related to a widespread cerebral microangiopathy and is due to a genetic mutation in SNORD118, responsible for stabilisation of the large ribosomal subunit during assembly.

Postoperative hydrocephalus management may cause delays in adjuvant treatment following paediatric posterior fossa tumour resection: a multicentre retrospective observational study.

INTRODUCTION: Hydrocephalus persists in 10-40% of children with posterior fossa tumours (PFT). A delay in commencement of adjuvant therapy (AT) can negatively influence survival. The objective of this study was to determine whether postoperative cerebrospinal fluid (CSF) diversion procedures caused potentially preventable delays in AT. METHODS: A retrospective study of children diagnosed with PFT requiring AT from 2004 to 2018 from two large centres was conducted. Data on histology, timing of ventriculo-peritoneal shunt (VPS) insertion, and AT was collected. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) score was calculated. The primary outcome was delay in AT beyond 40 days post-resection. Progression-free and overall survival were assessed. RESULTS: Out of 196 primary PFT resections, 144 fitted the inclusion criteria. Mean age was 6.57 ± 4.62. Histology was medulloblastoma (104), ependymoma (27), and others (13). Forty patients had a VPS inserted; 17 of these experienced a delay in AT. A total of 104 patients were not shunted; 15 of these had delayed AT (p = 0.0007). Patients who had a VPS insertion had longer intervals from surgery to commencement of AT (34.5 vs 30.8, p = 0.05). There was no significant difference in mCPPRH score between those who had a VPS (4.03) and those who did not (3.61; p = 0.252). Multivariable linear regression modelling did not show a significant effect of VPS or mCPPRH on progression-free survival or OS. CONCLUSION: CSF diversion procedures may cause a preventable delay in the initiation of adjuvant therapy. Early post-operative VP shunt insertion, rather than a 'wait and see policy' should be considered in order to reduce this delay.

Neuroimaging of paediatric pineal, sellar and suprasellar tumours: a guide to differential diagnosis.

INTRODUCTION: Pineal, sellar and suprasellar tumours in children comprise a wide range of diseases with different biological behaviours and clinical management. Neuroimaging plays a critical role in the diagnosis, treatment planning and follow up of these patients, but imaging interpretation can prove challenging due to the significant overlap in radiological features. MATERIALS AND METHOD: A review of the literature was performed by undertaking a search of the MEDLINE and EMBASE databases for appropriate MeSH terminology. Identified abstracts were screened for inclusion and articles meeting the objectives of the review were included. RESULTS AND CONCLUSION: In this article, we review radiological appearances of common and uncommon pineal, sellar and suprasellar tumours occurring in the paediatric population. We discuss the importance of anatomical localization, clinical information and cerebrospinal fluid tumour markers, and propose a practical approach to differential diagnosis. Lastly, we discuss future directions and prospective new imaging strategies to support state-of-the-art patient care.

Left-handedness should not be overrated as a risk factor for postoperative speech impairment in children after posterior fossa tumour surgery: a prospective European multicentre study.

PURPOSE: Cerebellar mutism syndrome (CMS) is a severe neurological complication of posterior fossa tumour surgery in children, and postoperative speech impairment (POSI) is the main component. Left-handedness was previously suggested as a strong risk factor for POSI. The aim of this study was to investigate the relationship between handedness and the risk of POSI. METHODS: We prospectively included children (aged < 18 years) undergoing surgery for posterior fossa tumours in 26 European centres. Handedness was assessed pre-operatively and postoperative speech status was categorised as either POSI (mutism or reduced speech) or habitual speech, based on the postoperative clinical assessment. Logistic regression was used in the risk factor analysis of POSI as a dichotomous outcome. RESULTS: Of the 500 children included, 37 (7%) were excluded from the present analysis due to enrolment at a reoperation; another 213 (43%) due to missing data about surgery (n = 37) and/or handedness (n = 146) and/or postoperative speech status (n = 53). Out of the remaining 250 (50%) patients, 20 (8%) were left-handed and 230 (92%) were right-handed. POSI was observed equally frequently regardless of handedness (5/20 [25%] in left-handed, 61/230 [27%] in right-handed, OR: 1.08 [95% CI: 0.40-3.44], p = 0.882), also when adjusted for tumour histology, location and age. CONCLUSION: We found no difference in the risk of POSI associated with handedness. Our data do not support the hypothesis that handedness should be of clinical relevance in the risk assessment of CMS.

Surveillance imaging of grade 1 astrocytomas in children: can duration and frequency of follow-up imaging and the use of contrast agents be reduced?

PURPOSE: The optimum strategy for the surveillance of low-grade gliomas in children has not been established, and there is concern about the use of gadolinium-based contrast agents (GBCAs), particularly in children, due to their deposition in the brain. The number of surveillance scans and the use of GBCAs in surveillance of low-risk tumours should ideally be limited. We aimed to investigate the consistency and utility of our surveillance imaging and also determine to what extent the use of GBCAs contributed to decisions to escalate treatment in children with grade 1 astrocytomas. METHODS: This was a retrospective single-centre study at a tertiary paediatric hospital. All children with a new diagnosis of a non-syndromic World Health Organization (WHO) grade 1 astrocytoma between 2007 and 2013 were included, with surveillance imaging up to December 2018 included in analysis. The intervals of surveillance imaging were recorded, and imaging and electronic health records were examined for decisions related to treatment escalation. RESULTS: Eighty-eight patients had 690 surveillance scans in the study period. Thirty-one patients had recurrence or progression leading to treatment escalation, 30 of whom were identified on surveillance imaging. The use of GBCAs did not appear to contribute to multidisciplinary team (MDT) decisions in the majority of cases. CONCLUSION: Surveillance imaging could be reduced in number and duration for completely resected cerebellar tumours. MDT decisions were rarely made on the basis of post-contrast imaging, and GBCA administration could therefore potentially be restricted in the setting of surveillance of grade 1 astrocytomas in children.

Intraventricular haemorrhage and posthaemorrhagic ventricular dilatation: moving beyond CSF diversion.

Advances in medical care have led to more premature babies surviving the neonatal period. In these babies, germinal matrix haemorrhage (GMH), intraventricular haemorrhage (IVH) and posthaemorrhagic ventricular dilatation (PHVD) are the most important determinants of long-term cognitive and developmental outcomes. In this review, we discuss current neurosurgical management of IVH and PHVD, including the importance of early diagnosis of PHVD, thresholds for intervention, options for early management through the use of temporising measures and subsequent definitive CSF diversion. We also discuss treatment options for the evolving paradigm to manage intraventricular blood and its breakdown products. We review the evidence for techniques such as drainage, irrigation, fibrinolytic therapy (DRIFT) and neuroendoscopic lavage in the context of optimising cognitive, neurodevelopmental and quality of life outcomes in these premature infants.

A persistent craniopharyngeal canal with recurrent bacterial meningitis: case report and literature review.

BACKGROUND: A persistent craniopharyngeal canal (PCC) is a rare but treatable anatomical abnormality that causes recurrent meningitis and should be considered as a differential diagnosis. CASE REPORT: We report a case of an 8-year-old boy who presented with recurrent meningitis associated to his PCC. Surgical repair was performed, and no further episodes occurred.

Neurosurgical experience of managing optic pathway gliomas.

BACKGROUND: Optic pathway gliomas (OPGs), also known as visual pathway gliomas, are debilitating tumors that account for 3-5% of all pediatric brain tumors. They are most commonly WHO grade 1 pilocytic astrocytomas and frequently occur in patients with neurofibromatosis type 1. The location of these tumors results in visual loss and blindness, endocrine and hypothalamic dysfunction, hydrocephalus, and premature death. Their involvement of the visual pathways and proximity to other eloquent brain structures typically precludes complete resection or optimal radiation dosing without incurring significant neurological injury. There are various surgical interventions that can be performed in relation to these lesions including biopsy, cerebrospinal fluid diversion, and partial or radical resection, but their role is a source of debate. This study catalogues our surgical experience and patient outcomes in order to support decision-making in this challenging pathology. METHODS: A retrospective review of all cases of OPGs treated in a single center from July 1990 to July 2020. Data was collected on patient demographics, radiographic findings, pathology, and management including surgical interventions. Outcome data included survival, visual function, endocrine, and hypothalamic dysfunction. RESULTS: One hundred twenty-one patients with OPG were identified, and 50 of these patients underwent a total of 104 surgical procedures. These included biopsy (31), subtotal or gross total resection (20 operations in 17 patients), cyst drainage (17), Ommaya reservoir insertion (9), or cerebrospinal fluid diversion (27). During the study period, there was 6% overall mortality, 18% hypothalamic dysfunction, 20% endocrine dysfunction, and 42% had some cognitive dysfunction. At diagnosis 75% of patients had good or moderate visual function in at least one eye, and overall, this improved to 83% at the end of the study period. In comparison the worst eye had good or moderate visual function in 56%, and this reduced to 53%. Baseline and final visual function were poorer in patients who had a surgical resection, but improvements in vision were still found-particularly in the best eye. DISCUSSION/CONCLUSION: OPG are debilitating childhood tumor that have lifelong consequences in terms of visual function and endocrinopathies/hypothalamic dysfunction; this can result in substantial patient morbidity. Decisions regarding management and the role of surgery in this condition are challenging and include cerebrospinal fluid diversion, biopsy, and in highly select cases cystic decompression or surgical resection. In this paper, we review our own experience, outcomes, and surgical philosophy.

Ventriculoatrial and ventriculopleural shunts as second-line surgical treatment have equivalent revision, infection, and survival rates in paediatric hydrocephalus.

PURPOSE: Ventriculoatrial (VA) and ventriculopleural (VPL) shunts are used as alternatives when CSF diversion to the peritoneal compartment with a ventriculoperitoneal (VP) shunt is not possible. The objective of this study is to compare directly the shunt survival and complications for both procedures in this setting in children. METHODS: A retrospective analysis of 54 consecutive patients who underwent VA (36) or VPL (18) shunt insertion between January 2002 and December 2017 was conducted. RESULTS: The overall mean follow-up was 4.1 (SD 4.3) years, 2.8 (SD 4.1) for VPL and 4.7 (SD 4.4) for VA shunts, respectively (p = 0.11). Twenty-four (66.7%) patients in the VA group and 9 (50.0%) in the VPL group underwent shunt revision (p = 0.236); mean number of revisions was 2.2 (SD 3.0) and 0.94 (SD 1.4) in the VA and VPL groups (p = 0.079). Median time to failure was 8.5 (IQr 78, range 0-176) months for VA and 5.50 (IQr 36, range 0-60) for VPL shunts (log rank (Mantel-Cox) 0.832). Shunt survival at 3, 6, 12 and 30 months was 60.6, 51.5, 36.4 and 27.3%, respectively, for VA and 56.3, 43.8, 37.5 and 37.5% for VPL shunts (log rank (Mantel-Cox) test value 0.727). The infection rate was 13.8% for VA and 5.6% for VPL shunts (p = 0.358). Four patients with VPL shunts (22.2%) developed pleural effusions. Fourteen deaths (25.9%) were recorded during follow-up, 8 (22.2%) in the VA and 6 (33.3%) in the VPL group (p = 0.380); two of the deaths in the VA group were shunt-related. CONCLUSION: This study demonstrates that the outcomes of VA and VPL shunts, when used as second-line surgical treatment in paediatric hydrocephalus, were similar, as were the revision, infection and survival rates. The shorter longevity of these shunts compared with the general shunted population may reflect the complex nature of these children.

Post-haemorrhagic hydrocephalus is associated with poorer surgical and neurodevelopmental sequelae than other causes of infant hydrocephalus.

PURPOSE: This retrospective cohort study aimed to investigate the surgical and neurodevelopmental outcomes (NDO) of infant hydrocephalus. We also sought to determine whether these outcomes are disproportionately poorer in post-haemorrhagic hydrocephalus (PHH) compared to other causes of infant hydrocephalus. METHODS: A review of all infants with hydrocephalus who had ventriculoperitoneal (VP) shunts inserted at Great Ormond Street Hospital (GOSH) from 2008 to 2018 was performed. Demographic, surgical, neurodevelopmental, and other clinical data extracted from electronic patient notes were analysed by aetiology. Shunt survival, NDO, cerebral palsy (CP), epilepsy, speech delay, education, behavioural disorders, endocrine dysfunction, and mortality were evaluated. RESULTS: A total of 323 infants with median gestational age of 37.0 (23.29-42.14) weeks and birthweight of 2640 g (525-4684 g) were evaluated. PHH was the most common aetiology (31.9%) and was associated with significantly higher 5-year shunt revision rates, revisions beyond a year, and median number of revisions than congenital or "other" hydrocephalus (all p < 0.02). Cox regression demonstrated poorest shunt survival in PHH, related to gestational age at birth and corrected age at shunt insertion. PHH also had the highest rate of severe disabilities, increasing with age to 65.0% at 10 years, as well as the highest CP rate; only genetic hydrocephalus had significantly higher endocrine dysfunction (p = 0.01) and mortality rates (p = 0.04). CONCLUSIONS: Infants with PHH have poorer surgical and NDO compared to all other aetiologies, except genetic hydrocephalus. Research into measures of reducing neurodisability following PHH is urgently required. Long-term follow-up is essential to optimise support and outcomes.