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

Fetal hydrocephalus is a condition involving excessive accumulation of intraventricular cerebrospinal fluid with ventricular dilation. It often leads to malformation or devastating neurological consequences of developing fetal brains. Recent advances in fetal imaging have triggered the development of a ventriculoarterial shunt. However, there are still concerns about shunt clogging or obstruction with the existing devices. Here, we introduce a low-profile, ventriculoamniotic shunt device, integrated with a microflow sensor to relieve abnormal high intracranial pressure, while enabling real-time monitoring of the fluid dynamics. The shunt prototype is manufactured by using a low-profile flexible composite tubing and superelastic nitinol anchors. The flexible and stretchable microflow sensor is uniquely designed and fabricated by using two metallic nano membranes encapsulated by biocompatible silicone elastomer. Flow monitoring performance of the sensor is demonstrated in vitro using acustom-built flow circulation model with a peristaltic pump. The highly sensitive, microflow sensor measures various incoming fluid velocity from 0.037 to 0.3 m/s, corresponding to the capacitance changed from 0.49 pF to 1.43 pF. Collectively, we demonstrate the feasibility of a microflow sensor for direct integration with the ventriculoamniotic shunt device for the treatment of aqueductal stenosis.