Risk factors for failure of endoscopic third ventriculostomy for obstructive hydrocephalus

OBJECTIVE: This is a retrospective study to identify risk factors for failu re in the treatment of obstructive hydrocephalus with endoscopic third vent riculostomy (ETV). METHODS: The records for 89 patients, including 32 with ventriculoperitonea l or ventriculoatrial shunt malfunctions or infections, who underwent ETVs between 1993 and 1998, at our institution, were examined. Multiple variable s possibly related to failure were considered. These included age, sex, cau se of hydrocephalus, presence and function of ventriculoperitoneal/ventricu loatrial shunts, history of shunt revisions or infections, symptoms, preope rative imaging results, presence of retained shunt catheters, postoperative meningitis, and postoperative ventricular size, RESULTS: Twenty-nine patients (32.6%) required subsequent shunt replacement and/or ETV revision. Of these 29 reoperations, 12 procedures (41.4%) were performed within 2 weeks and only 3 were performed more than 10 months afte r the initial ETV procedure. The ventricular size remained unchanged in 75% of the cases on the day after ETV, in 57.4% at 3 months, in 48.2% at 6 mon ths, and in 41.8% at 1 year. Cine phase-contrast magnetic resonance imaging findings were consistent with postoperative symptomatic resolution in 96.3 % of the cases. Seven patients (7.9%) experienced complications related to ETV, all of which were transient. Significant risk factors in univariate an alyses were as follows: presence of Chiari Type I malformation (P = 0.003), shunt infection at presentation (P = 0.014), history of shunt infections ( P = 0.0004), three or more previous shunt revisions (P = 0.0018), and posto perative meningitis (P = 0.0001). Late-onset idiopathic aqueductal stenosis was a significant predictor of good outcomes (P = 0.044). These factors we re reanalyzed in a multivariate analysis, which confirmed a history of shun t infections and postoperative meningitis as independent risk factors. CONCLUSION: The risk of failure increases with intracerebral infection, lik ely because of obliteration of cerebrospinal fluid pathways.