Patent ID: 7559912

Claim:
A valve for use in treating hydrocephalus, comprising: a housing having an inlet and an outlet; a valve element disposed within the housing and effective to allow fluid to flow from the inlet in the housing to the outlet in the housing when a fluid pressure at the inlet is greater than a threshold pressure of the valve element; and an adjustment mechanism coupled to the valve element and effective to selectively adjust the threshold pressure up to a maximum threshold pressure of at least about 400 mm H 2 O at increments of about of 20 mm H 2 O or less; wherein the valve element comprises an aperture, a restricting element disposed within the aperture and having a width greater than a width of the aperture, and a biasing member coupled to the adjustment mechanism and effective to bias the restricting element against the aperture at the threshold pressure; wherein the restricting element comprises a ball having a diameter that is greater than a diameter of the aperture; and wherein at least a portion of the aperture is in the shape of a cone having a cone angle of at least about 70°, and wherein the ball has a diameter that is at least about 0.8 mm.