Hydrocephalus is commonly associated with paediatric posterior fossa tumours and their resection. This is commonly managed by ventriculoperitoneal shunt insertion, which is associated with a lifelong risk of malfunction, necessitating revisional surgery. Few opportunities ever arise for the patient to be free of the shunt and this risk. We describe three patients shunted for tumour-related hydrocephalus who subsequently developed spontaneous shunt independence. We discuss this in the context of the literature.
A single-centre retrospective case series analysis was performed using a departmental database. Case notes were retrieved from a local electronic records database, and images were reviewed using national Picture Archiving and Communication Systems.
Over a 10-year period, 28 patients underwent ventriculoperitoneal shunt insertion for tumour-related hydrocephalus. Of these, 3 patients (10.7%) went on to have their shunts successfully removed. Age at presentation varied from 1 to 16 years. In all cases, the patient required shunt externalization due to shunt or intra-abdominal infection. This was used as an opportunity to challenge the need for ongoing cerebrospinal fluid (CSF) diversion. In one case, this occurred only several months after a shunt blockage with intracranial pressure monitoring that proved her shunt dependence. All three patients tolerated this challenge, their shunt systems were removed without complication, and they remain free of hydrocephalus at last follow-up.
These cases reflect our poor understanding of the heterogenous physiology of patients with shunted hydrocephalus and underline the importance of challenging the need for CSF diversion at any appropriate opportunity.

BACKGROUND: Endoscopic third ventriculostomy (ETV) has become a standard and safe procedure for obstructive hydrocephalus. ETV can also play an important role in children presenting with shunt malfunction with an added advantage of shunt independence. Secondary ETV can be defined as either a redo endoscopic ventriculostomy done after primary ETV stoma closure or that done in cases presenting with shunt malfunction.
OBJECTIVE: The aim of our study was to evaluate the role of secondary ETV in the pediatric age group patients.
METHODS: This is a retrospective analysis of 36 children (<18 years) who underwent ETV after shunt malfunction and 4 children with ETV done after previous ETV stoma closure from 2004 until 2018. In all patients, the obstructive pattern suggesting aqueduct outflow obstruction was observed on MRI. Patients were followed up for a mean period of 4.25 years.
RESULTS: ETV was considered successful if the patient avoided a shunt insertion later on in their life. Considering this definition, a success rate of 72% was observed with secondary ETV for shunt malfunction whereas a success rate of 75% was observed after primary ETV failure without any major side effects in any of the patients.
CONCLUSIONS: ETV can be considered a primary treatment modality in children with shunt malfunction and has a good success rate in cases presenting with closure of previously performed ETV stoma.

We report a case of tumour-related hydrocephalus in a child treated with a ventriculo-peritoneal shunt which subsequently became infected with gram negative bacteria (Escherichia coli). After successful treatment of the infection the patient became shunt independent and has remained so for over 2 years. Gram negative ventriculitis is associated with diminished cerebro-spinal fluid production and we discuss the literature to date regarding this phenomenon.