Endoscopic Third Ventriculostomy in Hydrocephalus Patients with Functioning Ventriculoperitoneal Shunts: Challenging the Dictum That Shunts Treat All Types of Hydrocephalus. Patient Series

BACKGROUND Although ventriculoperitoneal shunting is standard for hydrocephalus, shunting may not be ideal for aqueductal stenosis. A cohort of patients with aqueductal stenosis displayed symptoms of over- and underdrainage, despite a patent ventriculoperitoneal shunt (VPS) and optimized valve settings. Endoscopic third ventriculostomies (ETVs) were performed in a subset of these patients with successful treatment of their underlying hydrocephalus, despite a functioning shunt. OBSERVATIONS All patients who had undergone ETV with a history of ventriculoperitoneal shunting were retrospectively reviewed. Patients experiencing over- or underdrainage symptoms despite a patent shunt were included. Cerebral aqueduct anatomy and third ventricle bowing were reviewed on preoperative imaging. Seven patients met the study criteria. All showed cerebral aqueductal stenosis and third ventricle bowing. After ETV, all patients demonstrated decreased third ventricle bowing and clinical improvement without the need for secondary cerebrospinal fluid (CSF) diversion. LESSONS Despite a functioning VPS, patients with aqueductal stenosis may not be adequately treated. The underlying reasons are not clearly understood but suggest abnormal CSF dynamics due to aberrant parenchymal compliance. The authors theorize that ETV can more effectively treat these patients. ETV can be considered a viable treatment option in aqueductal stenosis despite a patent VPS, challenging the traditional teaching that shunts ideally treat all types of hydrocephalus.