Obstruction of cerebrospinal fluid drainage systems

Hydrocephalus is a common neurological condition whose primary treatment consists of diverting, or shunting, cerebrospinal fluid from the cerebral ventricles to extracranial absorption sites. Unfortunately, chronic implantation of these shunt systems is often accompanied by occlusion of the proximal (ventricular) and distal catheters. Indeed, shunt malfunctions are practically inevitable, and tissue obstruction is the most common cause of this persistent problem. In order to promote better treatments for hydrocephalus, specifically the improvement of shunt function by reducing catheter occlusion, it is important to understand the mechanisms leading to shunt obstruction, and this review summarizes the types of cells and tissues that typically block catheters and provides evidence to support the role of localized neuroinflammation and the foreign body response as primary causes. An extensive description of the clinical features associated with hydrocephalus and shunt obstruction provides insight into the many risk factors that influence shunt function at both proximal and distal sites. Finally, in an effort to introduce novel approaches to prevent shunt obstruction, considerable attention is focused on recent experimental work on silicone surface characteristics and architecture, including a critical review of the in vitro and in vivo methods available to test shunt occlusion.