The "steppingstone" phenomenon: a new endoscopic finding in slit-ventricle syndrome

Slit-ventricle syndrome (SVS) seems to encompass various pathophysiological abnormalities, including overdrainage of cerebrospinal fluid (CSF) and craniocerebral disproportion after extracranial CSF shunt placement. These pathologies result in small ventricle morphologically, and the ventricular catheter is obstructed by the collapsed ventricular walls. Patients with intermittent headaches, small ventricles on neuroimaging, and slow refill of the shunt reservoir are diagnosed with SVS. In this report, we present a case of SVS treated endoscopically. We detected bulges in a zigzag line on the ventricular walls according to side holes of the ventricular tube, and named them "steppingstone" phenomenon. It is a curious finding which directly shows that the intermittent obstruction of the ventricular tube occurs in patients with SVS. No previous articles have reported this phenomenon, and it indicates adequate treatment for SVS should be provided.