In vitro performance of the fixed and adjustable gravity-assisted unit with and without motion-evidence of motion-induced flow.

Background Anti-siphon devices and gravitational-assisted valves have been introduced to counteract the effects of overdrainage after implantation of a shunt system. The study examined the flow performance of two gravitational-assisted valves (shunt assistant – SA and programmable shunt assistant – proSA, Miethke & Co. KG, Potsdam, Germany) in an in vitro shunt laboratory with and without motion.