Overview
Shunts have been used to treat hydrocephalus for more than 50 years. The devices allow excess cerebrospinal fluid to drain to another area of the body.
How It Works
A shunt usually consists of two catheters and a one-way valve. The valve regulates the amount, flow direction, and pressure of cerebrospinal fluid out of the brain’s ventricles.
As the pressure of cerebrospinal fluid inside the brain or spine increases, the one-way valve opens and the excess fluid drains to the downstream cavity.
Typically, the fluid gets “shunted” (moved) using the following shunt types:
- A ventriculoperitoneal (VP) shunt moves fluid from the ventricles of the brain to the abdominal cavity
- A ventriculoatrial (VA) shunt moves fluid from the ventricles of the brain to a chamber of the heart
- A lumboperitoneal (LP) shunt moves fluid from the lower back to the abdominal cavity
Fixed and Adjustable Pressure Cerebrospinal Fluid Valves
There are various types of shunt valves. The two most common are:
- Fixed pressure valves – These regulate the flow rate of the cerebrospinal fluid based on a predetermined pressure setting
- Adjustable valves – These valves can be non-invasively adjusted, using magnetic tools, to different pressure settings after surgery
Both of these valve types can include over-drainage protection in the form of a siphon control device. The purpose of this device is to minimise excessive drainage, due to gravity, when a person is in the upright position.