Clinical features of third ventriculostomy failures classified by fenestration patency

BACKGROUND: To evaluate strategies for treating endoscopic third ventriculostomy (ETV) failure, we assessed patients, clinical features at failure, and the outcome of VP shunt placement at re-operation, classifying patients by fenestration patency. METHODS: Thirty-six patients with failed ETV were evaluated retrospectively. All but 4 had cine phase-contrast magnetic resonance (MR) images at re-operation to determine whether the fenestration was patent, and were grouped into "patent" and "no flow" groups. Symptoms at re-operation, the interval to failure, and outcome of re-operation were compared between these groups. RESULTS: Progression of elevated intracranial pressure (ICP) signs was significantly more frequent in the "no flow" group than the "patent" group (p = 0.0025). The median interval to failure was 2.5 months, with no statistical difference between the "patent" group (median 4.0 months) and the "no flow" group (median 1.1 months). Re-operations consisted of 29 shunt placements, 4 redo ETVs, and 3 combinations of both. Kaplan-Meier estimation indicates that 41% of shunts would be expected to fail by 5.2 years. The success rate of shunt placement was somewhat worse in the "no flow" group, although the difference was not statistically significant (p = 0.066). Four patients in the "patent" group treated with shunt placements eventually became shunt-independent with continuously patent fenestration; these were considered delayed successes. CONCLUSION: Patients with signs of elevated ICP and "no flow" findings on MR should be given emergency treatment because they have a high risk of symptom progression. The clinical differences between "patent" and "no flow" fenestration at re-operation after ETV failure are considered to be worthy of further study.