Types of Valves
| Valve type | Description |
|---|---|
| Delta | Designed to prevent overdrainage. Remains closed until ICP reaches a predetermined level. Leaves shunted ventricle larger than the non-shunted ventricles. |
| Medium pressure cylindrical | Can lead to uneven drainage of ventricles. |
| Nulsen and Spitz | Contains two ball-valve units connected with a spring. Does not have an adjustable pressure setting. First mass produced valve used to treat hydrocephalus in 1956. |
| Spitz-Holter | Uses slits in silicone to avoid mechanical failure. |
| Anti-siphon | Prevents over drainage by preventing the siphon effect. The device closes when the pressure within the valve becomes negative relative to the ambient pressure. Prevents overdrainage that might occur when a patient sits, stands or rapidly changes posture. |
| Sigma | The Sigma valve operates on a flow-control mechanism as opposed to the pressure-control system of other valves. The device can regulate CSF flow changes without being programmed or surgically changed. The first iteration was introduced in 1987. Valve operated in three stages to prevent over and under drainage. |
Read more about this topic: Cerebral Shunt
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