Wireless Pressure Sensing Shunts

• US 20090112103A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Integra LifeSciences Switzerland Sàrl
• Original Assignee: Codman & Shurtleff Incorporated (Johnson & Johnson)
• Inventors: Kassem, Salim
• Granted Patent: US 9,204,812 B2
• Time in Patent Office: Days
• US Class Current: 600/488
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61M 27/006 Cerebrospinal drainage; Accessories therefor, e.g. valves

Abstract

Devices and methods useful for sensing or measuring a pressure and remotely indicating or communicating that pressure are provided. The devices and methods have particular utility in sensing pressures in implantable medical devices and more particularly in hydrocephalus shunts. In one exemplary embodiment, an implantable valve can include a housing having a reservoir adapted to receive fluid flow therethrough between an inlet port and an outlet port. The implantable valve can also include a needle-penetrable septum to allow fluid delivery to the reservoir and/or a needle guard disposed within the housing and adapted to protect the radio frequency tag from a needle penetrating into the housing. A radio frequency (RF) tag can be disposed within the reservoir and can be adapted to change one or more of its electromagnetic characteristics in response pressure applied thereto by fluid in or flowing through the reservoir. The RF tag can produce a response to a wireless signal characterized by the one or more electromagnetic characteristics that correlates to a pressure of fluid in or flowing through the reservoir.

Claims

1. An implantable valve, comprising:

a housing having a reservoir adapted to receive fluid flow therethrough between an inlet port and an outlet port;

a substrate disposed within said reservoir; and

a radio frequency tag disposed on the substrate within the reservoir and including circuitry adapted to change one or more electromagnetic characteristics in response to pressure applied thereto by fluid in the reservoir and to produce a response to a wireless signal characterized by the one or more electromagnetic characteristics that correlates to a pressure of fluid in the reservoir,

the radio frequency tag further including a memory for storing data, the memory residing on the same substrate as the circuitry adapted to change one or more electromagnetic characteristics in response to pressure applied thereto.

2. The implantable valve of claim 1, further comprising a needle guard disposed within the housing and adapted to protect the radio frequency tag from a needle penetrating into the housing.

3. The implantable valve of claim 1, wherein the one or more electromagnetic characteristics is selected from resonant frequency, harmonic spectra, and Q factor.

4. The implantable valve of claim 1, further comprising:

a valve assembly disposed within the housing and adapted to control a rate of fluid flowing through the housing,

wherein the radio frequency tag is adapted to measure a pressure of the fluid flowing within the housing.

5. The implantable valve of claim 1, wherein the radio frequency tag includes digital logic circuitry, the digital logic circuitry residing on the same substrate as the memory.

6. The implantable valve of claim 1, wherein the stored data includes any of sensor identification data, sensed pressure data, and patient data.

7. The implantable valve of claim 1, wherein the pressure of fluid in the reservoir detectably changes any of the shape and the capacitance of the radio frequency tag so as to change the one or more electromagnetic characteristics thereof.

8. The implantable valve of claim 1, wherein

the circuitry includes an inductor and a capacitor connected to form an electrical circuit having a resonant frequency, the capacitor comprising a pair of conductors separated by a dielectric;

and

a pressure of fluid in the reservoir detectably changes a distance between the pair of conductors,

wherein the distance between the pair of conductors correlates to any of the resonant frequency, harmonic spectra, and Q factor of the electric circuit.

9. An implantable valve, comprising:

a housing defining a reservoir for receiving fluid flow therethrough;

a valve assembly disposed in the housing and adapted to control a rate of fluid flow through the reservoir;

a substrate disposed within said reservoir; and

a radio frequency tag disposed on the substrate in the reservoir and including circuitry adapted to measure a pressure of fluid in the reservoir and to indicate the measured pressure via at least one electromagnetic characteristic of the radio frequency tag,

the radio frequency tag including a memory for storing data, the memory residing on the same substrate as the circuitry adapted to measure the pressure of fluid.

10. The implantable valve of claim 9, further comprising a needle guard disposed within the housing and adapted to protect the radio frequency tag from a needle penetrating through the septum.

11. The implantable valve of claim 9, wherein the at least one electromagnetic characteristic is selected from the group consisting of:

resonant frequency, harmonic spectra, and Q factor.

12. The implantable valve of claim 9, wherein the radio frequency tag comprises an antenna adapted to communicate to an external reading device.

13. The implantable valve of claim 12, wherein the radio frequency tag is adapted to communicate a radio frequency having the at least one electromagnetic characteristic to the external reading device upon receipt of a wireless signal from the external reading device.

14. The implantable valve of claim 9, wherein the pressure of fluid in the reservoir detectably changes the shape of the radio frequency tag so as to change the at least one electromagnetic characteristic of the radio frequency tag.

15. The implantable valve of claim 9, wherein

the circuitry includes an inductor and a capacitor connected to form an electrical circuit having a resonant frequency, the capacitor comprising a pair of conductors separated by a dielectric;

and

the pressure of fluid in the reservoir detectably changes a distance between the pair of conductors, wherein

the distance between the pair of conductors correlates to any of the resonant frequency, harmonic spectra, and Q factor of the electric circuit.

16. A method for measuring ventricular pressure, comprising:

positioning a distal end of a ventricular catheter within a patient'"'"'s ventricle;

coupling a proximal end of the ventricular catheter to a valve inlet formed on an implantable valve, and coupling a valve outlet formed on the valve to a drainage catheter such that fluid flows from the ventricle through a reservoir in the valve to the drainage catheter, wherein a rate of fluid flowing through the valve is controlled by a valve assembly disposed within the implantable valve;

wirelessly obtaining a pressure measurement of a pressure of fluid in the valve by detecting a electromagnetic characteristic a response of a radio frequency tag associated with the valve; and

storing data in a memory in the radio frequency tag.

17. The method of claim 16, wherein obtaining the pressure measurement comprises wirelessly receiving a response from the radio frequency tag to a signal and detecting at least one electromagnetic characteristic selected from the group consisting of:

resonant frequency, harmonic spectra, and Q factor.

18. The method of claim 16, wherein obtaining the pressure measurement includes detecting a change in one or more electromagnetic characteristics a response of the radio frequency tag associated with the valve.

19. The method of claim 16, wherein obtaining the pressure measurement includes wirelessly transmitting a signal to the radio frequency tag and measuring power received from the radio frequency tag.

20. The method of claim 16, wherein the radio frequency tag includes circuitry having a resonance frequency for sending pressure and, on the same substrate, a memory for storing data.