MEMS electrochemical patency sensor for detection of hydrocephalus shunt obstruction

Currently there are no practical methods to definitively diagnose the obstruction failure of hydrocephalus shunts without surgical intervention, resulting in suboptimal treatment and needless patient suffering. We present the first MEMS electrochemical patency sensor for direct and quantitative tracking of shunt patency and obstruction. The impact of electrode size, temperature, flow, and hydrogen peroxide (H₂O₂) plasma sterilization on sensor function was evaluated and sensor performance in the presence of static and dynamic obstruction was demonstrated. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance (~8.5%) due to an increase in ionic mobility. H₂O₂ plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure.