Intracranial pressure monitoring as an early predictor of third ventriculostomy outcome.

Endoscopic third ventriculostomy (ETV) is a routinely used alternative to ventriculoperitoneal shunt in patients with obstructive hydrocephalus. We attempted to determine the usefulness of the surgeon's intraoperative impression and postoperative period intracranial pressure monitoring that may help guide clinicians in predicting the early functional outcome of ETV.Patients who underwent ETV between 2006 and 2011 were retrospectively reviewed. The sample included 63 patients (23 female and 40 male), between the ages of 13 and 69 years. In each case, the surgeon's intraoperative impression, cerebrospinal fluid (CSF) samplings, and postoperative intracranial pressure (ICP) monitoring (via transduced external ventricular drain for up to 72 hours) was recorded and evaluated in light of functional outcome of ETV at discharge and early follow up (1-2 months).ICP monitoring predicted initial function of the ETV in 51 cases (80.9%) and in 12 cases (19%) suggested ETV failure. Monitoring has a positive predictive value (PPV) of 76.3% and a negative predictive value (NPV) of 100% whereas the surgeon's intraoperative impression of future function had a PPV of 76.5% and NPV of 76.9%. CSF sampling has a much poorer predictive quality because the wide confidence interval and a PPV of 63.6% and NPV 38.2%. In our series the evidence of sepsis as a result of external ventricular drain was found to be 11.67%. Subgroup analysis, removing the patients with posterior fossa tumors, results in increased PPV (85.7%) of ICP monitoring.ETV is a valuable means of treating obstructive hydrocephalus. By considering the surgeon's intraoperative impression and postoperative ICP monitoring course, some of the uncertainty around its functional outcome can be overcome. The surgeon's impression and the ICP monitoring offer approximately the same predictive quality for ETV outcome.