Treatment: Shunts
Fixed-pressure valve
A fixed-pressure valve is a shunt valve set to drain at a single, unchangeable pressure.
In short: Fixed-pressure valve
- It drains at one set pressure that cannot be changed afterward.
- It is simpler than a programmable valve.
- It is not affected by magnets the way some programmable valves are.
- Changing the setting requires replacing the valve.
What it is
A fixed-pressure valve is a shunt valve set to drain at a single, predetermined pressure that cannot be changed after implantation. It is a simpler alternative to a programmable (adjustable) valve.
Understanding Fixed-pressure valve
A fixed-pressure valve is chosen at a particular setting (such as low, medium, or high) at the time of surgery, and that setting remains constant. Its simplicity means there is no setting to be inadvertently changed by magnets or MRI, which is an advantage in that respect. The trade-off is that if the drainage needs to be changed — for example, because of overdrainage or underdrainage — the valve itself must be surgically replaced, rather than adjusted non-invasively. The choice between a fixed-pressure and a programmable valve is individualized, weighing simplicity against the flexibility of later adjustment.
Why it matters
Understanding the fixed-pressure valve helps families see the trade-off between a simple valve that cannot be inadvertently changed and a programmable one that can be adjusted without surgery — a choice made for each person's situation.
Common questions
What is a fixed-pressure valve?
A valve set to drain at one pressure that cannot be changed afterward.
Can magnets change it?
No — it has no adjustable setting.
What if the drainage needs to change?
The valve must be surgically replaced.
Bottom line
A fixed-pressure valve drains at one unchangeable setting; it is simple but requires replacement to change drainage, unlike a programmable valve.
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