The Diamond valve is a hydrocephalus valve enabling an auto-regulated drainage of the CSF from the cerebral ventricles to the peritoneum or right atrium of the heart.
Diamond uses “flow technology” – as opposed to the pressure based mechanism of the other types of valves -, automatically regulating the flow through the valve at a rate close to that of CSF secretion and thereby relieving intracranial pressure.
One of its primary advantages is to allow a compensation of the differential pressures caused by the changes in a patient’s position, just like an anti-siphon device would do.
The device is made of two silicone differential pressure valve mechanisms, connected by an elastic tube, with an aperture (slit) at the side wall which acts as a flow regulating mechanism. Each valve opens in response to predetermined differential pressure (low pressures from 20 mm H2O to 60 mm H2O, and high pressure over 170 mm H2O) and closes when differential pressure has dropped below the predetermined level.
Theory of operations:
At low pressure, the performance of the valve is controlled by the low pressure valve.
In the mid range, the flow regulating mechanism responds to pressure to control flow.
At high pressures, the high pressure valve provides progressive pressure relief to prevent hypertension.
There are two models of Diamond valves:
- The Diamond valve original model is most frequently used to treat children’s hydrocephalus.
- The Diamond II model, which includes a reservoir allowing priming when pumping and access to the device for CSF sampling or drug injection, is most commonly used to treat adult patients suffering from NPH.
Like the CRx valve, the Diamond valve does not contain any metallic part to eliminate artefact risk during MRI exams
Diamond Valve |
Diamond II Valve |
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