Adjustable drainage valve
A drainage valve intended to be implanted and to drain the cerebrospinal fluid, including: a body defining a chamber into which there open an inlet port and an outlet port, a stopper capable of at least partially, or indeed completely, closing off the inlet port, a resilient return member exerting a resilient push force on the stopper towards the inlet port in order to open or close the port, a rotor housed in the chamber, able to rotate about an X-axis pivot and including a cam track on which the resilient return member rests such that the force exerted by the resilient return member on the stopper is modified by the rotation of the rotor.
1. A drainage valve intended to be implanted under the skin of a patient and to drain cerebrospinal fluid, said valve comprising:
a body defining a chamber into which there open an inlet orifice and an outlet orifice for the cerebrospinal fluid,
a shutter able to shut off the inlet orifice at least partially, or even fully,
an elastic return member designed to exert an influence on the shutter so as to push it, elastically, toward the inlet orifice so that the passage of cerebrospinal fluid through the inlet orifice is possible only if its pressure is greater than or equal to an opening pressure,
a rotor housed in the chamber, able to rotate about an axis X between two extreme positions and comprising a camway against which the elastic return member bears so that the influence exerted by the elastic return member on the shutter is modified by the rotation of the rotor,
the camway being defined by an interior profile of the rotor, directed toward the axis X, so that the elastic return member exerts, on the camway of the rotor, a force referred to as a “pulling force” comprising a component that is centrifugal with respect to the axis X.
2. The valve as claimed in claim 1 , the camway extending over more than 320° about the axis X of rotation of the rotor.
3. The valve as claimed in claim 2 , the camway extending over more than 370° about the axis X of rotation of the rotor.
4. The valve as claimed in claim 1 , the camway being designed to provide first and second end stops for the elastic return member preventing the rotor from rotating beyond first and second extreme positions, in the first and second directions of rotation of the rotor, respectively.
5. The valve as claimed in claim 1 , in which the camway has no break in slope, extends in a spiral about the axis X, and the gradient is substantially constant.
6. The valve as claimed in claim 1 , in which the elastic return member is mounted to rotate, with respect to the body, about an axis Y substantially parallel to the axis X and comprises a lever arm in mobile contact with the camway and a bearing arm pressing against the shutter, the lever and bearing arms being connected to one another by a pivot passing through the axis Y,
the lever arm forming, with the bearing arm, a sector of angle intersecting the axis X,
the direction of the lever arm being defined, when the valve is observed along the axis X, by the straight line passing through the axis Y and by the point at which the lever arm bears against the camway, and
the direction of the bearing arm being defined, when the valve is observed along the axis X, by the straight line passing through the axis Y and the point at which the bearing arm presses against the shutter.
7. The valve as claimed in claim 6 , in which the lever arm in mobile contact with the camway comprises a rigid or flexible rod, which is able to move and/or deform in a plane perpendicular to the axis X, distinct from and parallel to a plane perpendicular to the axis X and passing through the camway, and a substantially axial cam follower in mobile contact with the camway.
8. The valve as claimed in claim 1 , in which said elastic return member exerts said pulling force for all angular positions of said rotor.
9. The valve as claimed in claim 1 , the camway being defined by a cavity formed in the rotor, defined by a slot, a groove or a recess, or by a raised run of material.
10. The valve as claimed in claim 1 , the elastic return member and the rotor being configured to allow a valve opening pressure to be set in a range of an amplitude greater than 200mmH 2 O, or even greater than 350mmH 2 .
11. The valve as claimed in claim 1 , the rotor comprising a magnetic dipole formed of two micromagnets that are fixed or linearly mobile with respect to the rotor in a direction substantially radial with respect to the axis X and able to collaborate with rotor locking means so as to lock said rotor in a plurality of predetermined angular indexing positions.
12. The valve as claimed in claim 1 , in which, in at least one range of opening pressures,
the rotor may be positioned in a plurality of predetermined angular indexing positions and the increment between two opening pressures corresponding to two successive angular positions of the rotor is constant.
13. The valve as claimed in claim 1 , in which, in at least one range of opening pressures,
the rotor may be positioned in a plurality of predetermined angular indexing positions and the increment between two opening pressures corresponding to two successive angular positions of the rotor is variable.
14. The valve as claimed in claim 13 , in which said increment or said gradient evolves substantially exponentially as the rotor rotates.
15. The valve as claimed in claim 1 , in which the camway is configured to define several ranges of opening pressures, the opening pressure evolving differently according to which range of opening pressures is considered.
16. The valve as claimed in claim 15 , in which
the rotor may be positioned in a plurality of predetermined angular indexing positions, the increment between two opening pressures corresponding to two successive angular indexing positions being constant in several ranges of successive angular positions of the rotor, the increment increasing, from one range to the next, and
the positions of the rotor may evolve continuously and the gradient of opening pressure as a function of the angular position of the rotor is constant in several ranges of successive angular positions of the rotor, said gradient increasing, from one range to the next.
17. The valve as claimed in claim 1 , in which the elastic return member comprises either a rigid lever arm and a flexible bearing arm, or a flexible lever arm and a rigid bearing arm.
18. The valve as claimed in claim 1 , in which the rotor may be locked in twenty-four predetermined angular positions separated from one another by 15° , a rotation of the rotor in the clockwise direction, when looking at the external face of the rotor, leading to an increase in the opening pressure.
19. The valve as claimed in claim 1 , in which the axis of rotation of the rotor is off-centered with respect to the center of the chamber in which the rotor is housed and/or with respect to the axis connecting the cerebrospinal fluid inlet and outlet orifices.
20. The valve as claimed in claim 1 , in which, in at least one range of opening pressures, the positions of the rotor may evolve continuously and the gradient of opening pressure as a function of the angular position of the rotor is constant.
21. The valve as claimed in claim 1 , in which, in at least one range of opening pressures, the positions of the rotor may evolve continuously and the gradient of the opening pressure as a function of the angular position of the rotor is variable.