Rupture of a flow aneurysm secondary to spontaneous extracranial to intracranial revascularisation in the posterior fossa following radiation-induced vasculopathy for cerebellar tumour.

Paediatric patients receiving cranial irradiation therapy for brain tumours are at increased risk of cerebrovascular complications. Radiation-induced moyamoya syndrome (MMS) is a well-recognised complication of this. We present a case of an 8-year-old boy with a history of medulloblastoma, who underwent surgical excision followed by post-operative adjuvant oncological treatment. Six years later, he developed cerebellar/intraventricular haemorrhage. He underwent an emergency external ventricular drain (EVD) insertion followed by posterior fossa suboccipital craniotomy. On dural opening, an abnormal vessel was visualised on the surface of the right cerebellar hemisphere, which was not disturbed. No obvious abnormalities were identified intra-operatively. Cerebral catheter angiography confirmed the presence of a right-sided occipital artery (OA) to posterior inferior cerebellar artery (PICA) extracranial to intracranial (EC-IC) bypass with a zone of the distal PICA territory supplied by this EC-IC bypass. A presumed flow aneurysm originated from the bypass in the distal PICA, identified as cause for the haemorrhage. We highlight a rare cause for intracranial haemorrhage in this cohort of patients. Children who have undergone radiotherapy may have exquisitely sensitive cerebral vasculature and need careful vigilance and evaluation for vasculopathic complications following spontaneous haemorrhage.

Paediatric spinal cord low-grade gliomas-evaluation and management of post-surgical residual disease.

PURPOSE: To assess the evaluation and management of post-surgical residual disease for low-grade intramedullary spinal cord tumours (IMSCT) in childhood. METHODS: A single-centre retrospective review of low-grade IMSCTs treated between 2000 and 2019. All surgeries were performed with intent of safe maximal resection guided by intra-operative neurophysiological monitoring (IONM). Pre- and post-operative MRIs were reviewed to assess the extent of resection (EOR), recorded as follows: gross total resection (GTR), near total resection (NTR), sub-total resection (STR) and partial resection (PR). Outcome measures were time to recurrence, need for and modality of additional therapy and ambulatory status at last follow-up. RESULTS: Thirty patients underwent surgery for IMSCT (median age 6.9 years). EOR was GTR = 8, NTR = 4, STR = 9, PR = 9. All patients were alive at last follow-up (median follow-up 73 months [IQR 93 months]). Eighteen patients (60%) remained radiologically stable. Twelve patients (40%) developed recurrence during surveillance. Progression free survival was significantly better in cases with GTR + NTR in comparison to either STR or PR (p = 0.039). 10/30 (33%) patients were treated with additional therapy. At last follow-up, 26/30 patients were independently mobile. CONCLUSION: Survival rates for low-grade IMSCT are excellent. Radical micro-surgical resection, guided by IONM provides effective means of balancing the objectives of maximal safe resection, functional outcome and tumour control. Whilst evidence of 'residual disease' was identified in over 2/3 of immediate post-operative MRI scans, additional treatment was required in only 1/3 of cases. Critical appraisal of post-operative imaging findings is required to better define 'residual disease'. Small volume residual disease (< 5%) does not compromise progression-free survival.