Wireless breach detection

Abstract

Methods and systems for detecting wall breach in inflatable prostheses rely on intrusion of a body fluid or inflation medium to electrically alter a signaling circuit. In one embodiment, an open portion of a circuit is closed to enable or modify a transmitted signal. In another embodiment, electrical current is generated to power an electrical transmission.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] The present application is a continuation-in-part of application Ser. No. 11 / 170,274 (Attorney Docket No. 022209-000400US), filed on Jun. 28, 2005, which was a continuation-in-part of application Ser. No. 11 / 122,315 (Attorney Docket No. 022209-000230US), filed on May 3, 2005, and claims the benefit under 35 USC § 119(e) of prior provisional application No. 60 / 629,800 (Attorney Docket No. 02209-000210US), filed on Nov. 19, 2004, the full disclosures of which are incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to implantable devices and methods and systems for detecting their malfunction or failure or impending malfunction or failure. [0004] All implants of devices, especially those indicated for long term use, in the human body are highly regulated and must meet c...

AI Technical Summary

Benefits of technology

[0016] Alternatively, the circuit components may include spaced-apart conductors which are electrically coupled to the signaling circuit to “close” the signaling circuit to permit current flow when exposed to a body fluid and / or device contents by a wall breach. Alternatively, the circuit may be altered, enabled or otherwise modified by a sufficient flow of electrolytes to enable, interpret, disrupt, or modify a signal emission. The circuit components may include spaced apart conductors which are coupled to the signaling circuit to detect a change in resistance, capacitance, impedance, or voltage. Since the breach could be small and intermittent as it starts, it can be difficult to detect as a flow but the cumulative gain or loss of the electrolytes from the contents or surrounding body fluids could cause a change in the resistance, capacitance, or impedance across the conductors. Alternatively, the detection circuit is closed and the contact of the contents or the body fluids with the conductors could cause a break, disruption, or change in the functioning of the circuit. In the exemplary embodiments described below, the conductors may comprise meshes, films, or other relatively large surface areas covering most or all of the wall so that breach at any point in the wall will provide the intended electrically conductive bridging between the conductors. The coupling of the conductors may also cause, alter, or enable a signal emission to alert the patient of the breach or potential breach. The spaced-apart conductors can have any one of a variety of shapes or configurations, continuous configurations, such as plates and films, or discontinuous configurations, such as lattices, meshes, and the like, can be placed in various locations, preferably near interior portions of the device where body fluids will pool to enhance sensitivity and reliability of the detection.

[0018] The signaling circuit can be active or passive. In a preferred embodiment, the signaling circuit will comprise a passive transponder and antenna which are adapted to be powered and interrogated by an external reader. Such transponder circuitry may conveniently be provided by using common radiofrequency identification (RFID) circuitry where the transponder and tuned antenna are disposed on or within a protected area in the prosthesis and connected to remaining portions of the signaling circuit. Passively powered circuitry is particularly preferred in devices with on board batteries where the amount of energy stored in the battery generally determines the functional product life. The antenna and transponder could be located in close proximity to the detection circuitry or placed elsewhere in the device or another part of the body. For example, by connecting the transponder circuitry to “open” conductors which is closed in the presence of body fluids and / or inflation medium, the signal emitted by the transponder upon interrogation by an external reader may be altered. Thus, the patient or medical professional may interrogate the prosthesis and determine whether or not the prosthesis remains intact or the threat of an impending breach exists. This is a particularly preferred approach since it allows the user to determine that the transponder circuitry is functional even when a breach has not occurred.

[0024] Compromise of the device typically starts with a somewhat linear split or tear in surface of the device wall or covering from mechanical fatigue or handling damage. As the split propagates, it will expose more and more lines of the lattice or area of the film to the body fluids and or device contents. Consequently, as the size and seriousness of the breach increases, the probability of detection increases. Embedding the detection material in the covering such as the wall of the balloon further enables detection before a full breach of the entire thickness of the device wall.

[0026] The transmitter can be a simple wireless signal generator triggered by an electric current or preferably a transponder using the well-established RFID technology, i.e., produces a wireless signal when triggered by an interrogating signal. The electric charge generated or the electric current enabled by the probe in contact with the body fluids or device contents changes the logic state thereby enabling the transmitter to emit or causes it to emit a wireless signal. Typically, the transponder is powered by the interrogating radio frequency signal so that no power source of its own is required. Alternatively, the transmitter could be powered by a micro battery or by the electrical power generated by a chemical reaction. For protection from degradation by an acidic and electrolyte solution and become potentially toxic, the transmitter or transponder circuit is encased in a highly resistant material, such as silicone rubber or stainless steel. The transmitter or transponder circuit can be placed on the exterior, embedded in the wall, or preferably in the interior of the device for shielding from chemical degradation and mechanical stress. It can be placed in any orientation, preferably in the plane where the antenna is most sensitive and the transmitter is most effective in sending and receiving signals through body tissue overlying the device.

Problems solved by technology

These and other devices may contain potentially bioincompatible materials, such as batteries, circuitry, synthetic chemicals, and the like.

Since the breach could be small and intermittent as it starts, it can be difficult to detect as a flow but the cumulative gain or loss of the electrolytes from the contents or surrounding body fluids could cause a change in the resistance, capacitance, or impedance across the conductors.

Alternatively, the detection circuit is closed and the contact of the contents or the body fluids with the conductors could cause a break, disruption, or change in the functioning of the circuit.

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