LAUSR

Hydrocephalus (HCP) is a chronic neurological brain disorder caused by a malfunction of the cerebrospinal fluid (CSF) drainage mechanism in the brain. The current standard method to treat HCP is a shunt system. Unfortunately, the shunt system suffers from complications including mechanical malfunctions, obstructions, infections, blockage, breakage, overdrainage, and/or underdrainage. Some of these complications may be attributed to the shunts' physically large and lengthy course making them susceptible to external forces, siphoning effects, and risks of infection. Additionally, intracranial catheters artificially traverse the brain, and drain the ventricle rather than the subarachnoid space. We report a 3D-printed MEMS (Micro-Electro-Mechanical-System) based implantable valve to improve HCP treatment. This device provides an alternative approach targeting restoration of near natural CSF dynamics by artificial arachnoid granulations (AGs), natural components for CSF drainage in the brain. The valve, made of hydrogel, aims to regulate the CSF flow between the sub-arachnoid space and the superior sagittal sinus, in essence substituting for the obstructed arachnoid granulations. The valve, operating in a fully passive manner, utilizes hydrogel swelling feature to create non-zero cracking pressure, PT ~ 47.4 ± 6.8 mmH2O, as well as to minimize reverse flow leakage, QO ~ 0.7 µl/min on bench-top experiments. The additional measurements performed in realistic experimental setups using a fixed sheep brain also deliver comparable results, PT ~ 113.0 ± 9.8 mmH2O and QO ~ 3.7 µl/min. In automated loop functional tests, the valve maintains functionality during maximum 1536 cycles with the PT variance of 44.5 mmH2O < PT < 61.1 mmH2O and negligible average reverse flow leakage rates ~ 0.3 µl/min.