From the case:
Programmable cerebrospinal fluid shunt
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A Codman Hakim programmable VP shunt is demonstrated. The valve setting is approximately 140 mmH2O.
Case Discussion
The paper by Lollis et al provides a reference for the identification of programmable shunt valves and the interpretation of programmable shunt valve settings. There are a few types depending on the manufacturer. The type demonstrated on this radiograph is Codman Hakim type.
The programmable valve is an important advancement in that it provides the option of changing the opening pressure of the valve transcutaneously compared to the fixed pressure valves.
Here the valve pressure is set to 140 mmH2O.