Intracranial pressure monitor

Claim 2

Apparatus for sensing pressure within a cavity in the body of a living entity, comprising: means deformable in response to pressure within the cavity, said means comprising a housing formed of non-porous and electrically non-conductive material, the housing defining a chamber, a predetermined mass of fluid disposed within the chamber, and, pressure responsive means carried on the housing and extending into the chamber, said pressure responsive means being formed of non-porous and elastically compliant material and being deformable by pressure imposed on the apparatus to change the volume occupied by the mass of fluid within the chamber; and circuit means for absorbing electromagnetic radiation imposed thereon from externally of the circuit means at frequencies indicative of the deformation of the first-mentioned means.

Claim 3

The apparatus of claim 1 and further comprising: means housing the first-mentioned means and the circuit means, the housing means being totally implantable within the aforesaid cavity; means for imposing electromagnetic radiation on the circuit means within the implanted housing means; and, means for detecting the frequency at which the circuit means most efficiently absorbs the imposed electromagnetic radiation.

Claim 4

The apparatus of claim 2 and further comprising means for converting the detected frequency to a corresponding pressure reading and for displaying the pressure reading.

Claim 5

The apparatus of claim 2 wherein at least portion of the imposing means and the detecting means are disposed on a mounting substrate, the substrate having an aperture therein for receiving discrete tool means for positioning the housing means at a desired location within the aforesaid cavity.

Claim 6

The apparatus of claim 1 wherein the fluid comprises nitrogen gas.

Claim 7

The apparatus of claim 1 and further comprising at least two electrically conductive surfaces disposed in opposing relation to each other and movable relative to each other in response to deformation of the pressure responsive means, the surfaces forming at least a capacitive portion of the circuit means.

Claim 8

The apparatus of claim 6 and further comprising inductive means disposed in proximity to the electrically conductive surfaces, the, inductive means forming an inductive portion of the circuit means.

Claim 9

The apparatus of claim 1 wherein the inductive means comprise a coil of electrically conductive material.

Claim 10

The apparatus of claim 8 wherein the coil is electrically connected to each of the electrically conductive surfaces to form a resonant circuit.

Claim 11

The apparatus of claim 1 wherein the pressure responsive means comprise at least one bellows formed of an electrically conductive material and having a substantially planar end portion extending into the chamber, the apparatus further comprising: electrically conductive means disposed within the chamber and having a substantially planar surface opposing the planar end portion of the bellows, said surface and said planar end portion being movable relative to each other in response to deformation of the bellows, the surface of the electrically conductive means and the planar end portion of the bellows forming at least a capacitive portion of the circuit means.

Claim 12

The apparatus of claim 10 wherein the electrically conductive means is comprised of a second bellows and the substantially planar surface thereof is an end portion of the second bellows.

Claim 13

The apparatus of claim 10 and further comprising a coil of electrically conductive material, the coil being electrically connected to the bellows and to the electrically conductive means, the coil forming an inductive portion of the circuit means.

Claim 14

The apparatus of claim 12 wherein the coil is wrapped around the outer portion of the housing means.

Claim 15

The apparatus of claim 12 wherein the coil of electrically conductive material comprises a planar helix.

Claim 16

The apparatus of claim 1 and further comprising: means encapsulating the housing means, the encapsulating means being totally implantable within the aforesaid cavity; and a fluid disposed within the encapsulating means between interior walls of said encapsulating means and the housing means.

Claim 17

The apparatus of claim 15 and further comprising collar means for mounting the encapsulating means within the aforesaid cavity, the encapsulating means and the collar means having engaging portions formed respectively thereon, the encapsulating means being movable within the collar means to a desired location therein.

Claim 18

The apparatus of claim 16 wherein the engaging portions on the encapsulating means and on the collar means comprise mating threads.

Claim 19

The apparatus of claim 17 and further comprising slot means in at least the upper portions of the encapsulating means to facilitate rotation of the encapsulating means within the collar means.

Claim 20

The apparatus of claim 16 wherein the encapsulating means has a portion thereof which is structurally relatively thin to facilitate transfer of pressure externally imposed on the encapsulating means to the fluid disposed within the encapsulating means and externally of the housing means.

Claim 21

The apparatus of claim 1 wherein the housing has an aperture therein used for sealing the mass of fluid within the chamber, the apparatus further comprising means for sealing the aperture to prevent introduction of extraneous gaseous material into the chamber, the last-mentioned means comprising pin means insertable into the aperture, and solder means for joining the pin means to a portion of the exterior surface of the housing.

Claim 22

The apparatus of claim 20 wherein the last-mentioned means comprise a collar of metal formed about the periphery of the aperture, the solder means joining to the collar.

Claim 23

Apparatus for sensing pressure within a cavity in the body of a living entity, comprising: means deformable in respone to pressure within the cavity, said means comprising a first housing, a second housing disposed within the first housing, thereby to define first and second chambers within said first housing between interior walls of the first housing and exterior walls of the second housing, the second housing defining an interior chamber therewithin and further having an aperture communicating the interior chamber with one of the aforementioned chambers, a fluid disposed within the aforesaid chambers, and, pressure responsive means carried on the second housing and extending into the interior chamber, the pressure responsive means being deformable by pressure imposed on the apparatus to change the volume occupied by the mass of fluid within the interior chamber; and, circuit means for absorbing electromagnetic radiation imposed thereon from externally of the circuit means at frequencies indicative of the deformation of the first-mentioned means.

Claim 24

Apparatus for sensing pressure within a cavity in the body of a living entity, comprising: means deformable in respone to pressure within the cavity, said means comprising a first housing, a second housing disposed within the first housing, thereby to define first and second chambers within said first housing between interior walls of the first housing and exterior walls of the second housing, the second housing defining an interior chamber therewithin and further having an aperture communicating the interior chamber with one of the aforementioned chambers, a fluid disposed within the aforesaid chambers, and, pressure responsive means carried on the second housing and extending into the interior chamber, the pressure responsive means being deformable by pressure imposed on the apparatus to change the volume occupied by the mass of fluid within the interior chamber; and, circuit means for absorbing electromagnetic radiation imposed thereon from externally of the circuit means at frequencies indicative of the deformation of the first-mentioned means.

Claim 25

The apparatus of claim 22 and further comprising at least two electrically conductive surfaces disposed in opposing relation to each other and movable relative to each other in response to deformation of the pressure responsive means, the surfaces forming at least a capacitive portion of the circuit means.

Claim 26

The apparatus of claim 22 wherein the pressure responsive means comprise at least one bellows formed of electrically conductive material and having a substantially planar end portion extending into the interior chamber, the interior of the bellows communicating with the one of the first or second chamber which does not communicate with the interior chamber through the aforementioned aperture.

Claim 27

The apparatus of claim 24 and further comprising: electrically conductive means disposed within the interior chamber and having a substantially planar surface opposing the planar end portion of the bellows said surface and said planar end portion being movable relative to each other in response to deformation of the bellows.

Claim 28

The apparatus of claim 24 and further comprising a coil of electrically conductive material, the coil being electrically connected to the bellows and to the electrically conductive means.

Claim 29

The apparatus of claim 26 wherein the coil is wrapped about an outer portion of the second housing means.

Claim 30

The apparatus of claim 22 and further comprising inductive means disposed in proximity to the electrically conductive surfaces, the inductive means forming an inductive portion of the circuit means.

Claim 31

The apparatus of claim 28 wherein the inductive means comprise a coil of electrically conductive material.

Claim 32

The apparatus of claim 28 wherein the coil is electrically connected to each of the electrically conductive surfaces to form a resonant circuit.

Claim 33

The apparatus of claim 22 wherein the fluid comprises silcone liquid.

Claim 34

The apparatus of claim 22 and further comprising: means housing the first-mentioned means and the circuit means, the housing means being totally implantable within the aforesaid cavity; means for imposing electromagnetic radiation on the circuit means within the implanted housing means; and, means for detecting the frequency at which the circuit means most efficiently absorbs the imposed electromagnetic radiation.

Claim 35

The apparatus of claim 22 and further comprising: means for converting the detected frequency to a corresponding pressure reading and for displaying the pressure reading.

Claim 36

Apparatus for sensing pressure within the cranial cavity of a living entity, comprising: a first housing; a second housing disposed within the first housing, thereby to define first and second chambers within said first housing between interior walls of the first housing and exterior walls of the second housing, the second housing defining an interior chamber therewithin and further having an aperture communicating the interior chamber with one of the aforementioned chambers; a fluid disposed within the interior chambers and within the first and second chambers; sealing means for sealing the first chamber from communication with the second chamber; and, pressure responsive means carried on the second housing and extending into the interior chamber, the pressure responsive means being deformable by pressure imposed on the apparatus to reduce the mass of fluid within the interior chamber.

Claim 37

Apparatus for sensing pressure within the cranial cavity of a living entity, comprising: a first housing; a second housing disposed within the first housing, thereby to define first and second chambers within said first housing between interior walls of the first housing and exterior walls of the second housing, the second housing defining an interior chamber therewithin and further having an aperture communicating the interior chamber with one of the aforementioned chambers; a fluid disposed within the interior chambers and within the first and second chambers; sealing means for sealing the first chamber from communication with the second chamber; and, pressure responsive means carried on the second housing and extending into the interior chamber, the pressure responsive means being deformable by pressure imposed on the apparatus to reduce the mass of fluid within the interior chamber.

Claim 38

Apparatus for sensing pressure within the cranial cavity of a living entity, comprising: a housing formed of non-porous and electrically non-conductive material, the housing defining a chamber; a predetermined mass of fluid disposed within the chamber; pressure responsive means carried on the housing and extending into the chamber, said pressure responsive means being formed of non-porous and elastically compliant material and being deformable by pressure imposed on the apparatus to reduce the volume of the mass of fluid within the chamber; and, circuit means for absorbing electromagnetic radiation imposed thereon from externally of the apparatus at frequencies indicative of the deformation of the pressure responsive means, the circuit means including at least two electrically conductive surfaces at least one of which is carried on the pressure responsive means, the conductive surfaces being disposed in opposing relation to each other and movable relative to each other in response to deformation of the pressure responsive means, the surfaces forming at least a capacitive portion of the circuit means, the circuit means also including inductive means disposed in proximity to the electrically conductive surfaces, the inductive means forming an inductive portion of the circuit means, the inductive means being electrically connected to each of the electrically conductive surfaces to form a resonant circuit.

Claim 39

Apparatus for sensing pressure within the cranial cavity of a living entity, comprising: a housing formed of non-porous and electrically non-conductive material, the housing defining a chamber; a predetermined mass of fluid disposed within the chamber; pressure responsive means carried on the housing and extending into the chamber, said pressure responsive means being formed of non-porous and elastically compliant material and being deformable by pressure imposed on the apparatus to reduce the volume of the mass of fluid within the chamber; and, circuit means for absorbing electromagnetic radiation imposed thereon from externally of the apparatus at frequencies indicative of the deformation of the pressure responsive means, the circuit means including at least two electrically conductive surfaces at least one of which is carried on the pressure responsive means, the conductive surfaces being disposed in opposing relation to each other and movable relative to each other in response to deformation of the pressure responsive means, the surfaces forming at least a capacitive portion of the circuit means, the circuit means also including inductive means disposed in proximity to the electrically conductive surfaces, the inductive means forming an inductive portion of the circuit means, the inductive means being electrically connected to each of the electrically conductive surfaces to form a resonant circuit.