Spinal Fluid Flow Sensor for Implantable Spine Shunts

Author: Joseph Manna

Field of Study: Electrical Engineering

Program Affiliation: SCALE

Faculty Mentors: David Klotzklotzkin

Easel: 46

Timeslot: Morning

Abstract: Hydrocephalus is a long term condition where cerebrospinal fluid builds up in the brain’s ventricles, which increases pressure and requires a surgically implanted shunt to continuously drain the fluid. These shunts are meant to last a lifetime, but if they become blocked, the patient needs emergency surgery to replace them. The goal of this research is to develop a mounted system that can continuously monitor flow in the shunt using capacitive conductive measurements. The idea is that CSF conductivity naturally changes throughout the day, so if fluid is flowing, small fluctuations in conductivity should be detected. No change in conductivity implies there is no flow. To test this concept, this study utilizes LTspice to model a C4D sensor that simulates realistic flow rates and conductivity variations in a CSF shunt. It then evaluated two different sensing methods, direct contact sensors and capacitively coupled contactless conductivity detection, both of which are very sensitive to conductivity changes. The results show that both approaches can successfully detect whether the shunt is functioning or blocked in a controlled lab setting.