Implantable Wireless Sensor

• US 20090030291A1
• Filed: 07/18/2008
• Published: 01/29/2009
• Est. Priority Date: 09/16/2003
• Status: Active Grant

• Current Assignee: St. Jude Medical Luxembourg Holdings Ii S.A.R.L.
• Original Assignee: CardioMEMS Incorporated
• Inventors: White, Jason, Fonseca, Michael A., O'Brien, David, Allen, Mark, Stern, David, Kroh, Jason
• Granted Patent: US 9,265,428 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02014 Determining aneurysm
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making
• CPC Class Codes: Y10T 29/49069 Data storage inductor or core
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 by assembling coil and core

Abstract

A wireless sensor for indicating a physical state within an environment includes a unitary housing defining a cavity. A structure located within the cavity of the housing has elements providing capacitance, the elements being arranged such that the distance and thereby the capacitance of the structure changes when a physical state of the environment changes. The structure has a resonant frequency based at least in part on the capacitance of the structure when in the presence of a fluctuating electromagnetic field. When the sensor is positioned within an environment and is subjected to a fluctuating electromagnetic field, the resonant frequency indicates the physical state of the environment.

Claims

1-25. -25. (canceled)

26. A wireless sensor for indicating a physical state of an environment, comprising:

a unitary housing comprising a cavity having first and second opposed walls; and

a structure located within said cavity of said housing having elements providing capacitance, said elements being spaced apart from one another by at least one distance and arranged such that the at least one distance and thereby the capacitance of said structure changes when a physical state of the environment changes, said structure having a resonant frequency based at least in part on the capacitance of the structure when the structure is in the presence of a fluctuating electromagnetic field.

whereby, when the sensor is positioned within an environment and is in the presence of a fluctuating electromagnetic field, said resonant frequency indicates the physical state of the environment.

27. The sensor of claim 26, wherein at least one of said first and second walls of said cavity has a portion of reduced thickness relative to the remaining walls defining the cavity such that the at least one wall deforms in response to a predetermined range of environmental pressure.

28. The sensor of claim 26, wherein said housing comprises a material selected from the group consisting of glass, fused silica, sapphire, quartz, or silicone and silicon.

29. The sensor of claim 26, wherein the physical property is pressure.

30. The sensor of claim 26, wherein the structure located within the cavity further provides an inductance.

31. The sensor of claim 26, wherein the structure is a wire spiral.

32. The sensor of claim 26, wherein the housing is from about 0.5 in. to about 1 in. in length and from about 0.1 in. to about 0.5 in. in width.

33. The sensor of claim 32, wherein the housing has a thickness of from about 0.05 in. to about 0.30 in.

34. The sensor of claim 26, further comprising a stabilizer operatively associated with the sensor for stabilizing the sensor within the body of a patient.

35. The sensor of claim 34, wherein the stabilizer is configured to stabilize at least one of position, location, and orientation.

36. The sensor of claim 34, wherein the stabilizer comprises means arranged around the outer surface of the sensor for maintaining said housing in spaced apart relation from surrounding objects.

37. The sensor of claim 36, wherein the means arranged around the outer surface of the sensor for maintaining said housing in spaced apart relation from surrounding objects comprises a wire basket.

38. The sensor of claim 26, wherein the housing is substantially impervious to the passage of atoms and molecules into and out of said cavity.

39. The sensor of claim 26, wherein said housing comprises a material which elicits a medically acceptable level of biological reaction.

40. The sensor of claim 26, wherein said sensor further comprises a polymer coating applied to the exterior of said housing.

41. The sensor of claim 40, wherein said coating comprises silicone.

42. The sensor of claim 26, wherein said coils are oblong.

43. A system for delivering a sensor, comprising:

a sensor for wirelessly determining a physical property of an environment, which sensor comprises;

a unitary housing comprising a cavity having first and second opposed walls; and

mutually opposed coils located within said cavity on said first and second cavity walls so as to be disposed in generally parallel, spaced apart relation;

wherein said mutually opposed coils comprise a self-contained resonant circuit, and

wherein said resonant circuit is variable in response to a physical property of the environment within which it is located; and

means for delivering said sensor to a location within the body of a patient.

44. The system of claim 43, wherein the means for delivering said sensor to a location within the body of a patient comprises a guidewire.

45. The system of claim 43, wherein the means for delivering said sensor to a location within the body of a patient comprises a catheter.

46. The system of claim 43, further comprising an instrument for receiving and processing signals from the sensor corresponding to a change in said resonant circuit.

47. The system of claim 43, further comprising an instrument for inductively coupling to the sensor for determining changes in impedance corresponding to a change in said resonant circuit.

48. A method for measuring a physical property, comprising the steps of:

inserting into an environment a sensor comprising;

a unitary housing comprising a cavity having first and second opposed walls; and

mutually opposed coils located within said cavity on said first and second cavity walls so as to be disposed in generally parallel, spaced apart relation;

wherein said mutually opposed coils comprise a self-contained resonant circuit, and

wherein said resonant circuit is variable in response to a physical property of the environment within which it is located; and

receiving and processing signals from the sensor corresponding to a change in said resonant circuit.

49. The method of claim 48, wherein said step of inserting said sensor into an environment comprises the step of inserting said sensor into the body of a patient.