Assessment of the influence of operative factors in the success of endoscopic third ventriculostomy in children

Objective: To determine if operative factors correlate with success of endoscopic third ventriculostomy (ETV) in the treatment of hydrocephalus. Materials and methods: The ETV procedure video of 33 hydrocephalic children was reviewed. Mean age at operation was 76 months (range: 1-196). Success was defined as no need for shunt in the long term. We calculated the relative size of stoma as the percentage of stoma diameter to the distance between posterior clinoid-basilar artery. Factors analysed were: intra-operative haemorrhage, stoma size, thick/double third ventricular floor, pre-pontine adhesions presence, brisk cerebro-spinal fluid (CSF) flow through the stoma as well as hydrocephalus cause, previous shunt presence, CSF infection or haemorrhage and previous ETV. Analysis was performed using chi-square, linear regression, and one-way ANOVA. Results: Overall ETV success rate was 42%. Mean stoma size was 37%. For the entire group, none of the operative factors correlated statistically with success. Previous shunt presence adversely correlated with success (p=0.008). The highest success rate was in the aqueduct stenosis group. In patients without previous shunt (n=17), stoma size over 30% tended towards significance (p=0.094), CSF leak was adversely associated with ETV success (p=0.041) and mean stoma size was 41.3% in successful ETV and 27.8% in unsuccessful ETV (p=0.072). In patients with previous shunt (n=16), thin third ventricular floor was a negative predisposing factor (p=0.057). Conclusion: This study did not demonstrate a correlation between the presence of pre-pontine adhesions, double or thickened floor of third ventricle and ETV success. In patients without previous shunt, stoma size may correlate with success. CSF leak was strongly associated with failure.