A Low-Profile Flow Sensing System for Monitoring of Cerebrospinal Fluid with a New Ventriculoamniotic Shunt

Fetal hydrocephalus is a condition involvingexcessive accumulation of intraventricular cerebrospinal fluidwith ventricular dilation. It often leads to malformation ordevastating neurological consequences of developing fetalbrains. Recent advances in fetal imaging have triggered thedevelopment of a ventriculoamniotic shunt. However, there arestill concerns about shunt clogging or obstruction with theexisting devices. Here, we introduce a low-profile, ventriculoamniotic shunt device, integrated with a microflowsensor to relieve abnormal high intracranial pressure, whileenabling real-time monitoring of the fluid dynamics. The shuntprototype is manufactured by using a low-profile flexiblecomposite tubing and superelastic nitinol anchors. The flexibleand stretchable microflow sensor is uniquely designed andfabricated by using two metallic nanomembranes encapsulatedby biocompatible silicone elastomer. Flow monitoringperformance of the sensor is demonstrated in vitro using acustom-built flow circulation model with a peristaltic pump. The highly sensitive, microflow sensor measures variousincoming fluid velocity from 0.037 to 0.3 m/s, corresponding tothe capacitance changed from 0.49 pF to 1.43 pF. Collectively, we demonstrate the feasibility of a microflow sensor for directintegration with the ventriculoamniotic shunt device for thetreatment of aqueductal stenosis.