| miniNAV - description |
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The miniNAV was developed as a more compact valve that demonstrates improved performance in terms of obstruction-related problems and resistance against subcutaneous pressure.
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Fig. 1 shows a schematic cross section of the miniNAV.
The miniNAV consists of a robust
titanium casing (1) whose proximal end
contains a ball-cone valve. A spiral spring
(2) maintains the opening pressure of the
ball-cone valve and the sapphire ball (3)
ensures precise closure of the valve.
The inlet port (4) and the outlet port (5)
are also constructed of titanium. |
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| Fig. 1 |
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| Function |
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| The operating principle of the miniNAV is
illustrated in Fig. 3 and Fig. 4. |
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| Horizontal position |
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| Fig. 3 shows the miniNAV in the horizontal
position. The ball-cone valve is closed
and drainage is prevented.
Increasing intraventricular pressure (IVP) will eventually overcome
the spring force, which normally would keep the ball-cone valve closed.
The closing ball is pushed away from the
cone seal and a gap opens for CSF drainage. |
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