Pleomorphic xanthoastrocytoma with NTRK fusion presenting as spontaneous intracranial hemorrhage-case report and literature review.

Background: Pleomorphic xanthoastrocytoma (PXA) is a rare brain tumor that accounts for <1% of all gliomas. An in-depth understanding of PXA's molecular makeup remains a work in progress due to its limited numbers globally. Separately, spontaneous intracranial hemorrhage (pICH) is an uncommon but potentially devastating emergency in young children, often caused by vascular malformations or underlying hematological conditions. We describe an interesting case of a toddler who presented with pICH, later found to have a PXA as the underlying cause of hemorrhage. Further molecular interrogation of the tumor revealed a neurotrophic tyrosine receptor kinase (NTRK) gene fusion and CDKN2A deletion more commonly seen in infantile high-grade gliomas. The unusual clinicopathological features of this case are discussed in corroboration with published literature. Case presentation: A previously well 2-year-old male presented with acute drowsiness and symptoms of increased intracranial pressure secondary to a large right frontoparietal intracerebral hematoma. He underwent an emergency craniotomy and partial evacuation of the hematoma for lifesaving measures. Follow-up neuroimaging reported a likely right intra-axial tumor with hemorrhagic components. Histology confirmed the tumor to be a PXA (WHO 2). Additional molecular investigations showed it was negative for BRAFV600E mutation but was positive for CDKN2A homozygous deletion and a unique neurotrophic tyrosine receptor kinase (NTRK) gene fusion. The patient subsequently underwent second-stage surgery to proceed with maximal safe resection of the remnant tumor, followed by the commencement of adjuvant chemotherapy. Conclusion: To date, there are very few pediatric cases of PXA that present with spontaneous pICH and whose tumors have undergone thorough molecular testing. Our patient's journey highlights the role of a dedicated multidisciplinary neuro-oncology team to guide optimal treatment.

Complex lumbosacral spinal cord lipomas: A longitudinal study on outcomes from a Singapore children's hospital.

BACKGROUND: Total/near-total resection (TR/NTR) of complex lumbosacral lipomas (CSL) is reported to be associated with better long-term functional outcomes and lower symptomatic re-tethering rates. We report our institutional experience for CSL resection in affected children. METHODS: This is a single-institution, retrospective study. Inclusion criteria consist of patients with CSL with dorsal, transitional and chaotic lipomas based on Pang et al's classification. The study population is divided into 2 groups: asymptomatic patients with a normal preoperative workup referred to as 'prophylactic intent' and 'therapeutic intent' for those with pre-existing neuro-urological symptoms. Primary aims are to review factors that affect post-operative clean intermittent catheterization (CIC), functional outcomes based on Necker functional score (NFS), and re-tethering rates. RESULTS: 122 patients were included from 2000 to 2021. There were 32 dorsal lipomas (26.2 %), 74 transitional lipomas (60.7 %), and 16 chaotic lipomas (13.1 %). 82 % patients achieved TR/NTR. Favourable NFS at 1-year was 48.2 %. The re-tethering rate was 6.6 %. After multivariable analysis, post-operative CIC was associated with median age at surgery (p = 0.026), lipoma type (p = 0.029), conus height (p = 0.048) and prophylactic intent (p < 0.001). Next, extent of lipoma resection (p = 0.012) and the post-operative CSF leak (p = 0.004) were associated with re-tethering. Favourable NFS was associated with lipoma type (p = 0.047) and prophylactic intent surgery (p < 0.001). CONCLUSIONS: Our experience shows that TR/NTR for CSL is a feasible option to prevent functional deterioration and re-tethering. Efforts are needed to work on factors associated with post-operative CIC.

Selective dorsal rhizotomy using a 3D high definition exoscope.

Selective dorsal rhizotomy (SDR) is an established neurosurgical technique for children with spastic diplegia secondary to cerebral palsy. Meticulous intraoperative testing of individual nerve roots with electromyography in tandem with the on-site neurorehabilitation team is recommended for good clinical outcomes. The standard approach requires the neurosurgeons to spend extended time under the traditional operating microscope. In this video, the authors describe the use of a 3D exoscope system for SDR. Overall, the 3D exoscope improves ergonomics and reduces musculoskeletal fatigue for the operating neurosurgeons. Furthermore, it provides excellent visualization of important structures, allowing safe and efficient completion of the procedure. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23105.

Cerebrospinal fluid shunt malfunctions: A reflective review.

PURPOSE: Pediatric hydrocephalus is a common and challenging condition. To date, the ventriculoperitoneal shunt (VPS) is still the main lifesaving treatment option. Nonetheless, it remains imperfect and is associated with multiple short- and long-term complications. This paper is a reflective review of the current state of the VPS, our knowledge gaps, and the future state of shunts in neurosurgical practice. METHODS AND RESULTS: The authors' reflections are based on a review of shunts and shunt-related literature. CONCLUSION: Overall, there is still an urgent need for the neurosurgical community to actively improve current strategies for shunt failures and shunt-related morbidity. The authors emphasize the role of collaborative efforts amongst like-minded clinicians to establish pragmatic approaches to avoid shunt complications.

Cerebral X-linked Adrenoleukodystrophy Presenting As Enlarging Cavum Vergae Cyst: A Case Report.

The cavum vergae cyst (CVC) is an uncommon brain malformation. Most patients with CVC are asymptomatic and do not require neurosurgical intervention. Separately, cerebral X-linked adrenoleukodystrophy (X-ALD) is one of the phenotypes of a genetic peroxisomal disorder that is seldom managed by neurosurgeons. We report an unusual case of cerebral X-ALD presenting as an enlarging CVC in a child, and discuss its nuances in corroboration with the literature. A previously well six-year-old male presented with confusion and fever. Urgent neuroimaging demonstrated a large CVC with resultant hydrocephalus. Of note, there were symmetrical areas of signal changes in the periventricular white matter bilaterally involving the corpus callosum, thalami, cerebral peduncles, midbrain, and pons in his MRI. Further investigations performed as part of his medical workup reported high plasma concentrations of very long-chain fatty acids (VLCFA). Put together, a diagnosis of cerebral X-ALD was confirmed. Initially, an external ventricular drain was inserted directly into the CVC under stereotaxy to decompress it. Subsequently, endoscopic fenestration of the CVC was performed as the definitive treatment. He recovered uneventfully from the neurosurgical interventions and proceeded for the treatment of his cerebral X-ALD. To our knowledge, this is the first report of cerebral X-ALD presenting as a CVC in a patient. This case adds to the limited literature for both rare conditions and highlights the importance of a multidisciplinary approach to management.

Paediatric ventriculoperitoneal shunt failures: 12-year experience from a Singapore children's hospital.

PURPOSE: Cerebrospinal fluid (CSF) shunt failures in children are devastating. The primary aims of this study are to, firstly, review our institutional series of ventriculoperitoneal shunt (VPS) insertions and identify factors associated with shunt failure. METHODS: This is a single-institution, retrospective study conducted over a 12-year period. All patients under 18 years old with VPS inserted were included. Variables of interest such as patient characteristics, hydrocephalus aetiology, shunt implant details, and outcomes were subjected to statistical analyses. RESULTS: A total of 214 VPS patients were selected for this study. The mean age at VPS insertion was 6 months with a mean follow-up duration of 44 months. The most common type of hydrocephalus was obstructive (n = 142, 66.4%), and the most frequent aetiology was tumour-related (n = 66, 30.8%). The 30-day shunt failure rate was 9.3%: 9 infections (4.2%), 7 occlusions (3.3%), and 4 others (1.9%). After multivariable analysis, only recent central nervous system (CNS) infection prior to VPS insertion remained significant (OR 15.4 (1.3-175), p = 0.028). CONCLUSION: This is the first, large-scale local study focused on the shunt failure in Singaporean children. Significant findings in our study demonstrate that recently treated CNS infection is a factor associated with 30-day shunt failure while the values of CSF constituents were not contributory.

Withdrawal notice to Spinal dysraphism-perspectives from a Southeast Asian paediatric neurosurgical unit: WNEU, 173 (2023) 20134.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in WNEU, 172 (2023) 20066, https://doi.org/10.1016/j.wneu.2023.01.070. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Fibrofatty filum terminale: long-term outcomes from a Singapore children's hospital.

OBJECTIVE: The role of prophylactic detethering a fibrofatty filum terminale (FFT) remains equivocal. Furthermore, long-term studies focusing on urological outcomes are sparse. The aims of this study were to present an institutional experience on the perioperative and long-term outcomes of FFT surgery and to assess for factors that contribute to postoperative clean intermittent catheterization (CIC). METHODS: This was a single-institution, retrospective study conducted over a 20-year period. Patients younger than 19 years of age who underwent surgery for FFT were included. Variables of interest included patient demographics, clinical presentation, radiological findings, postoperative complications, and long-term need for CIC. Outcomes were measured using the Necker functional score and modified Hoffer Functional Ambulation scale score at 3, 6, and 12 months postdischarge. RESULTS: A total of 164 surgeries were performed for FFT from 2000 to 2020. The median age at surgery was 1.1 years, and the mean follow-up duration was 8.3 years. There were 115 patients (70.1%) who underwent prophylactic-intent surgery and 49 patients (29.9%) who underwent therapeutic-intent surgery. The proportion of therapeutic-intent surgeries increased significantly with age percentiles (0-20th, 21.9%; 20th-40th, 9.1%; 40th-60th, 18.2%; 60th-80th, 36.4%; and 80th-100th, 63.6% [p < 0.001]). Thirty patients (18.3%) had an associated syndrome, the most common (n = 19, 11.6%) being VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities). Forty-eight patients (29.3%) had an associated malformation (anorectal anomaly = 37, urogenital anomaly = 16, and sacral anomaly = 3). Cutaneous manifestation was the most common presentation (n = 96, 58.5%), followed by lower-limb neurological deficits (n = 21, 12.8%). A low-lying conus was present in 36.0% of patients (n = 59), and 16.5% had an associated syrinx (n = 27). There were 26 patients (18.8%) with an abnormal preoperative urodynamic study. Three patients (1.8%) had postoperative complications that required repeat surgery. There were no cases of CSF leakage. One patient (0.6%) developed retethering requiring another surgery. Postoperative CIC was required in 11 patients (6.7%). Multivariable analyses showed that an abnormal preoperative urodynamic study (adjusted OR 5.5 [95% CI 1.27-23.9], p = 0.023) and having an intraspinal syrinx (adjusted OR 5.29 [95% CI 1.06-26.4], p = 0.042) were associated with the need for CIC. CONCLUSIONS: The authors' results demonstrate that detethering surgery for FFT is a relatively safe procedure and can be performed prophylactically. Nonetheless, the risks of postoperative CIC should be emphasized during the preoperative counseling process.

Tethered cord secondary to focal nondisjunction of the primary neural tube: experience from a Singapore children's hospital.

PURPOSE: Tethered cord due to focal nondisjunction of primary neuralisation (FNPN) is a rare form of spinal dysraphism. We present our institutional experience in managing children diagnosed with FNPN. MATERIALS AND METHODS: This is a single institution, retrospective study approved by the hospital ethics board. Patients below 18 years of age diagnosed with CDS, LDM or their mixed lesions, and subsequently underwent intervention by the Neurosurgical Service, KK Women's and Children's Hospital, are included. RESULTS: From 2001 to 2021, 16 FNPN patients (50% males) were recruited. Eight of them had CDS (50.0%), seven had LDM (43.8%), and one patient had a mixed CDS and LDM lesion (6.2%). The average duration of follow up was 5.7 years and the mean age of surgery was 6 months old. Thirteen patients underwent prophylactic intent surgery (81.2%) and three had therapeutic intent surgery (18.8%). All patients did not have new neurological deficit or required repeat surgery for cord retethering. We observed that detethering surgery performed at or less than three months old was associated with having a wound infection (p = .022). CONCLUSIONS: Our study reports that early recognition and timely intervention are mainstays of management for FNPN. We advocate a multi-disciplinary approach for good outcomes.

Decompressive surgery in abusive head injury: Experience from a Singapore children's hospital and a review of literature.

PURPOSE: Abusive head trauma (AHT) is a major cause of morbidity and mortality in children. Studies on pediatric head injury observe that AHT patients often have a higher incidence of malignant cerebral oedema and, overall, worse prognosis. There are limited studies with a focus on the outcome of decompressive surgery in children with AHT. This is a study undertaken to review our institutional experience on the role of decompressive surgery in AHT patients and objectively assess its outcomes, in corroboration with current literature. METHODS: This is an ethics-approved, retrospective study. Inclusion criteria consist of all children with a diagnosis of AHT managed by the Neurosurgical Service, KK Women's and Children's Hospital. Demographical and clinical variables are incorporated in the statistical analyses. RESULTS: From 2011 to 2021, a total of 7 patients required decompressive surgery for AHT. Mean age of the cohort was 17.1 months (with the majority of patients being male (n = 5, 71.4%). During the follow-up period, there was 1 mortality (14.3%), 3 patients developed cerebral palsy (42.9%), and 3 patients had post-traumatic epilepsy (42.9%). With regards to functional outcome, 4 patients (57.1%) had a favorable KOSCHI score at 6 months follow-up. CONCLUSION: Decompressive surgery in children with AHT presents with its own unique challenges. We therein present our neurosurgical experience in decompressive surgery for this extremely vulnerable group of patients. Given the potential role of decompressive surgery in AHT, the development of an objective marker to select such patients who may benefit most from intervention should be the way forward.

Biopsy of paediatric brainstem intrinsic tumours: Experience from a Singapore Children's Hospital.

BACKGROUND: Biopsy of intrinsic brainstem tumours presumed to be diffuse midline gliomas (previously known as DIPG) is controversial. Surgery has risks of injury to the eloquent brainstem and may not have direct benefit to the patient. Technological improvements in operative adjuncts have allowed the role of biopsy for paediatric brainstem lesions to be revisited with new insights. This study aims to evaluate our institutional experience in brainstem biopsy. METHODS: This is an ethics-approved retrospective study based in KK Women's and Children's Hospital. Patients diagnosed with intrinsic brainstem tumours and managed by the Neurosurgical Service were included. Variables of interest included patient demographics, neuroimaging features, type of surgery, histological and molecular diagnosis, treatment, and outcomes. RESULTS: From 2006 to 2021, a total of 27 brainstem intrinsic tumours were referred to the Neurosurgical Service. Eleven (40.7 %) patients underwent stereotactic biopsy and 10 (37 %) had open biopsies. Histologically, 10 (37 %) were confirmed to be high grade gliomas, eight (29.6 %) were low grade gliomas and 3 (11.1 %) were malignant embryonal tumours. No negative diagnostic results or permanent postoperative complications were encountered. Five patients went on to have their tumours interrogated via next-generation sequencing to look for targetable mutations. The remaining 6 (22.2 %) patients did not undergo biopsy, whereby 1 of them is still alive after 6 years. CONCLUSION: Biopsy of paediatric brainstem intrinsic tumours is a safe procedure that concurrs with accurate tissue diagnosis. This option can be offered to affected patients, especially to identify relevant markers for targeted therapy.

Abusive head injury in the very young: outcomes from a Singapore children's hospital.

PURPOSE: Abusive head trauma (AHT) is a serious problem in children. The aims of this study are to identify risk factors that correlate with outcomes for those requiring neurosurgical intervention for very young children with AHT, assessment of variables associated with outcomes, and corroboration of our results with literature. METHODS: This is an ethics-approved, retrospective study. Inclusion criteria consisted of patients aged 2 years old or less with a diagnosis of AHT managed by the Neurosurgical Service, KK Women's and Children's Hospital. Demographical and clinical variables are incorporated in the statistical analyses. Logistic regression was applied to statistically significant variables for the risk prediction model. RESULTS: From 2000 to 2020, 24 patients required surgery for AHT. Timepoint was set at 12 months post-diagnosis. Univariate analyses demonstrated that patients with mild TBI were likely to have a favourable GOS-E Peds (p = 0.01), whereas radiological presence of cerebral oedema (p < .001), development of scar epilepsy (p = 0.021), and progression to cerebral palsy (p = 0.001) were associated with unfavourable GOS-E Peds. CONCLUSION: This is the first study focused on neurosurgical outcomes for very young children with AHT in Singapore. We advocate multidisciplinary efforts to improve outcomes for this devastating condition.

Monomodality versus Combined Therapy in Optic Pathway Gliomas-20-Year Experience from a Singapore Children's Hospital.

Introduction: The treatment of pediatric optic pathway gliomas (OPG) is challenging. At present, most centers provide individualized treatment to maximize progression free survival (PFS) and minimize morbidity. We aim to report our experience in the management of pediatric OPG, and investigate factors associated with an increased duration of remission after treatment. Methods: This is a single-institution study approved by the hospital ethics board. A retrospective review of consecutive OPGs managed from 2000 to 2020 was performed. Patients were divided into those managed with monomodality treatment (MT) and those who received combined therapy (CT). MT included various forms of surgery, chemotherapy and radiotherapy given alone, while CT involves a combination of surgery and adjuvant chemotherapy and/or radiotherapy. Results: Twenty-two patients were selected for this study. They had 40 treatment cycles; and a total follow up duration of 194.8 patient-years. Most of them were male (63.6%) and presented with visual deficits (72.7%). The mean age at initial presentation was 65 months and majority (86.4%) had their tumors arising directly from the optic chiasm, with 77.3% with hypothalamic extension. One patient had Neurofibromatosis type I (4.5%). The most common histological diagnosis was pilocytic astrocytoma (90.9%), followed by pilomyxoid astrocytoma (9.1%). The 5- and 10- year PFS were 46.2% and 36.4% respectively, while the 5- and 10-year OS were both 100%. When accounting for treatment type, there were 24 treatment cycles with MT (60.0%) and 16 CT (40.0%). After adjustment, treatments with MT were shown to have a shorter mean duration of remission (MT: 45 ± 49, CT: 84 ± 79 months; p = 0.007). Cox regression curve plotted after adjusting for patient's age at treatment demonstrated a significantly longer PFS in the CT group (p = 0.037). Conclusions: Our results suggest a significant survival benefit of CT over MT for affected patients due to the prolonged the duration of disease remission, for both primary and subsequent treatments. Nonetheless, we acknowledge that our study reflects the outcomes of treatment strategies that have evolved over time. We emphasize the need for collective efforts from a dedicated multidisciplinary team and international collaborations for better disease understanding.

Prevention and treatment of CSF leaks in congenital complex spinal lipomas.

BACKGROUND: Congenital complex spinal lipomas (CSL) are challenging lesions to treat. Cerebrospinal fluid (CSF) leaks are feared complications due to the risk of infection, and subsequent scarring that may promote retethering. Much has been written in the literature on the surgical technique of CSL resection with less emphasis placed on the prevention and management of CSF leak. METHOD: The authors describe the nuances in the prevention and management of CSF leaks in the context of CSL, including the operative approach, resection, closure and recommended postoperative care. CONCLUSION: CSF leaks are complications that can be minimized with deliberate steps and meticulous surgical technique.

Paediatric Cerebral Arteriovenous Malformation: Outcomes from a Singapore Children's Hospital.

OBJECTIVES: Paediatric brain arteriovenous malformation (bAVM) is a rare and distinct clinical entity. There is a growing body of literature that support the success of multimodality approaches for this difficult condition. The authors aim to firstly, describe our institutional experience with a consecutive series of patients and next, corroborate our results with current literature. MATERIAL AND METHODS: This is a single institution, retrospective study conducted over a 20-year period. Patients less than 19 years old with bAVM were included. Variables of interest included patient demographics, clinical presentation, neuroimaging features, bAVM characteristics and treatment modality. Functional outcomes were measured with modified Rankin scale (mRS). RESULTS: There were 58 paediatric bAVMs, presenting at a mean age of 8.7 ± 4.2 years, and followed up for a mean duration of 7.7 years. Thirty-six patients (62.1%) underwent microsurgical resection, 10 patients had stereotactic radiosurgery (17.2%) and 2 patients had endovascular treatment (3.4%). 50 patients (86.2%) had a favourable outcome at 1-year follow up. Microsurgical resection and SRS had similar obliteration rates (resection 83.3%; SRS 80.0%) and recurrence (resection 10.0%; SRS 12.5%). There were 6 cases of bAVM recurrence (12.8%). This subgroup was noted to be less than 7.5 years old at presentation (OR 15.0, 95% CI 1.56 - 144), and less likely to present with bAVM rupture (OR 0.11, 95% CI 0.01 - 0.96). CONCLUSION: This study describes our experience in managing paediatric bAVM, whereby monomodal therapy can still be effective. Of note, we also demonstrate the role of extended surveillance to detect recurrence.

Programmable Shunt Valves for Pediatric Hydrocephalus: 22-Year Experience from a Singapore Children's Hospital.

(1) Background: pediatric hydrocephalus is a challenging condition. Programmable shunt valves (PSV) have been increasingly used. This study is undertaken to firstly, to objectively evaluate the efficacy of PSV as a treatment modality for pediatric hydrocephalus; and next, review its associated patient outcomes at our institution. Secondary objectives include the assessment of our indications for PSV, and corroboration of our results with published literature. (2) Methods: this is an ethics-approved, retrospective study. Variables of interest include age, gender, hydrocephalus etiology, shunt failure rates and incidence of adjustments made per PSV. Data including shunt failure, implant survival, and utility comparisons between PSV types are subjected to statistical analyses. (3) Results: in this case, 51 patients with PSV are identified for this study, with 32 index and 19 revision shunts. There are 3 cases of shunt failure (6%). The mean number of adjustments per PSV is 1.82 times and the mean number of adjustments made per PSV is significantly lower for MEDTRONIC™ Strata PSVs compared with others (p = 0.031). Next, PSV patients that are adjusted more frequently include cases of shunt revisions, PSVs inserted due to CSF over-drainage and tumor-related hydrocephalus. (4) Conclusion: we describe our institutional experience of PSV use in pediatric hydrocephalus and its advantages in a subset of patients whose opening pressures are uncertain and evolving.

Molecular exploration of paediatric intracranial germinomas from multi-ethnic Singapore.

BACKGROUND: Germinomas (IG) account for up to 50% of all intracranial germ cell tumours. These tumours are reputed to be more prevalent in Oriental populations in comparison to Western cohorts. Biological characteristics of IG in other ethnic groups are unknown. Singapore is a multi-ethnic country with diverse cultures. Owing to inter-racial heterogeneity, the authors hypothesize there are molecular differences between paediatric IG patients in our local population. The aims of this study are exploratory: firstly, to identify molecular characteristics in this tumour type and circulating CSF unique to different racial cohorts; and next, to corroborate our findings with published literature. METHODS: This is a single-institution, retrospective study of prospectively collected data. Inclusion criteria encompass all paediatric patients with histologically confirmed IG. Excess CSF and brain tumour tissues are collected for molecular analysis. Tumour tissues are subjected to a next generation sequencing (NGS) targeted panel for KIT and PDGRA. All CSF samples are profiled via a high-throughput miRNA multiplexed workflow. Results are then corroborated with existing literature and public databases. RESULTS: In our cohort of 14 patients, there are KIT exon variants in the tumour tissues and CSF miRNAs corroborative with published studies. Separately, there are also KIT exon variants and miRNAs not previously highlighted in IG. A subgroup analysis demonstrates differential CSF miRNAs between Chinese and Malay IG patients. CONCLUSION: This is the first in-depth molecular study of a mixed ethnic population of paediatric IGs from a Southeast Asian cohort. Validation studies are required to assess the relevance of novel findings in our study.