A novel microdevice for the treatment of hydrocephalus: design and fabrication of an array of microvalves and microneedles

We present an implantable, microfabricated device for the treatment of hydrocephalus. Hydrocephalus is a medical condition, in which an abnormal accumulation of cerebrospinal fluid (CSF, a water-like fluid that circulates around and protects the brain and spinal cord.) occurs in the brain. The novel microdevice presented here mimics the function of natural one-way valves, arachnoid villi, found in the human brain. Hence, we name it microfabricated arachnoid villi (MAV). The MAV consists of an array of one-way microvalves and hollow microneedles. The one-way microvalves control flow based on pressure differential. A Parylene microvalve array with a dome petal geometry was designed and fabricated. Initial flow tests demonstrated the desired low cracking pressure of the valve and a sufficient mechanical stability. The hollow microneedle array was designed to pierce the dura mater membrane (A tough fibrous membrane covering the brain and the spinal cord and lining the inner surface of the skull.) and provide a conduit for CSF. An SU-8 microneedle array was designed and successfully microfabricated. The innovative MAV may open a new era in the treatment of hydrocephalus.