The miniNAV was developed as a more compact valve that demonstrates improved performance in terms of obstruction-related problems and resistance against subcutaneous pressure. The depiction below 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.
The depiction below 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.