Delayed hydrocephalus and visual field defect due to perianeurysmal inflammation after treating a large unruptured aneurysm with flow diverter and coil: A case report

Flow diverter (FD) placement is increasingly used to treat large supraclinoid aneurysms. Here, we report a case of hydrocephalus following FD placement. One patient in her 60 s underwent FD placement combined with coil embolization. Within 1 month, the patient started to show visual field defects and symptoms of hydrocephalus, which worsened within another month. We report that hydrocephalus developed acutely, without high protein levels in the cerebrospinal fluid, and as a complication using a Surpass Streamline. Although the precise mechanisms are unclear, our report suggests a different mechanism for the development of hydrocephalus after FD placement combined with coil embolization. •Hydrocephalus developed in an acute manner as the complication using Surpass Streamline.•Hydrocephalus developed without high protein level in cerebral spinal fluid as the complication using Surpass Streamline.•Severe perianeurysmal inflammation alone, not presenting aseptic meningitis, could be a cause for hydrocephalus.