Hydrocephalus: Reducing Catheter Failure and Improving Diagnostic Capabilities

DESCRIPTION (provided by applicant): Hydrocephalus is the inability to reabsorb spinal fluid and arises in the setting of various disease states leading to approximately 75,000 shunt insertions/revisions annually in the U.S. The basic technique of ventricular shunting has remained essentially unchanged since the 1950's with placement of the ventriculoperitoneal shunt (VPS) as the most common construct. Despite much innovation, the VPS continues to have an extremely high failure rate approximating 40 percent by one year and 98 percent by ten years regardless of the hardware type or technique of insertion. Statistically, the most common cause of failure is shunt obstruction at the proximal catheter (~60 percent) followed by valve failure. Mechanical failure typically occurs secondary to obstruction with particulates (blood/protein) or ingrowth of tissue (choroids plexus/ependyma), and it is addressed by surgically replacing the failed component(s). Shunt failure has obvious repercussions on medical costs, risks to life, and patient suffering: acute failure is often a neurosurgical emergency that can result in death; progressive failure involves vague symptoms (headache, nausea) that are difficult to diagnose, especially in children, and can lead to prolongedsuffering before shunt failure is accurately diagnosed. Diagnostic methods are costly, unreliable, and introduce secondary risks (e.g., radiation); each surgical intervention resets the clock on infection risk (5-15 percent); and shunt replacements represent 400 million in medical costs each year in the US. This project will address the main cause of shunt failure and develop methods to detect shunt failure if it does occur. In Aim 1, a maintenance routine for reducing tissue ingrowth at the proximal catheter will be tested in an animal model. Aim 2 of the project seeks to develop non-invasive methods to diagnose shunt obstruction. In Aim, 3 a battery-powered, pacemaker sized device will be constructed to perform the maintenance and diagnostic routines. The overall goal is to reduce shunt failure by 50 percent, which would greatly reduce suffering and healthcare costs caused by repeated shunt failures. Relevance Hydrocephalus is the failure in the ability to reabsorb cerebrospinal fluid and occurs in 1 in 500 live births. The common treatment is placing a shunt to drain fluid from the brain to another location in the body, and this system normally remains in place for life. However, shunts fail at an alarming rate - 40 percent fail by one year, and 98 percent fail by 10 years. We will develop a shunt maintenance routine to address the main cause of failure and diagnostics to test shunt function. PUBLIC HEALTH RELEVANCE: This project will lead to the development of anti-fouling techniques for preventing proximal catheter occlusion in hydrocephalus shunts and diagnostic techniques to assess for occlusion, and valve performance. The most common cause of failure for hydrocephalus shunts is obstruction in the proximal catheter. Success with Phase I will validate our innovative strategy for preventing these obstructions and will lead to future device development and reduced healthcare costs.