US20070123947A1 - Medical device packaging system - Google Patents

Abstract

A system, comprising a sterilizable package; an implantable medical device placed inside the sterilizable package; and an electrical interface electrically coupled to the implantable medical device and extending from inside the sterilizable package to outside the sterilizable package. In various embodiments, the interface may include package contacts electrically coupled to electrode terminals on the implantable medical device, patient terminals and conductors extending between the package contacts and the patient terminals.

Description

TECHNICAL FIELD
• The invention relates generally to implantable medical devices, and, in particular, to configurations of implantable medical device packaging systems.
BACKGROUND
• Implantable medical devices (IMDs) such as cardiac pacemakers, implantable cardiovertor defibrillators (ICDs), implantable loop recorders (ILRs), implantable drug pumps, neurostimulators, etc. are generally provided by manufactures in a sterilized package. The package commonly includes an external carton or container for holding a sterilized inner tray or pouch containing the IMD. The IMD is sterilized within the inner tray or pouch using appropriate sterilization methods such as steam, gas or ultrasonic sterilization. The inner tray or pouch is generally provided with a peelable or tearable seal that can be opened to drop the sterile IMD contained therein into a sterile field without compromising the sterility of the IMD or the sterile field. For example, an IMD packaging tray having an open top may be sealed closed with a paper lid that is peeled back at the time of an implant procedure to allow the IMD to be dropped out of the tray into the sterile field.
• Some packaging systems may include within the external carton or container an outer tray or pouch for carrying the sterilized inner tray or pouch. The inner tray or pouch and device contained therein may be sterilized within the outer tray or pouch. The outer tray or pouch may then be peeled open to drop the inner tray or pouch into the sterile field at the time of implant. An implanting physician or assistant may then open the inner tray or pouch within the sterile field.
• Pre-implant testing, electrophysiological mapping, or system testing is commonly performed at the beginning of an implantation procedure to ensure that a patient meets implantation criteria and/or to determine an optimal implant location for the IMD and/or associated electrodes. Such testing may be performed using the IMD since using the IMD itself would generally provide the most reliable test results. However, during pre-implant testing, considerable care must be taken to ensure that the IMD and associated leads remain sterile for implantation. Once the IMD is removed from the sterile packaging, the IMD cannot be re-shelved should the patient not meet implantation criteria. As such, external equipment is often substituted for making physiological measurements or performing electrophysiological mapping. Use of external equipment for performing testing or mapping includes certain limitations, however, since the electronics of the external equipment will generally be different than the electronics of the IMD. Signals measured by external equipment may not be the same as signals measured at the same location by the IMD. Even minor signal differences can limit the usefulness or reliability of such measurements for the purposes of pre-implant tests.
• Since IMDs tend to be costly devices, it is undesirable to open the IMD sterile packaging prior to knowing with reasonable certainty that the IMD is appropriate for the patient and that an acceptable implantation site for the device and/or leads can be identified. Furthermore, external equipment needed for performing pre-implant testing may not be readily available and requires extra space within the operating theater, which is often already crowded with equipment and personnel. Often a programmer that supports surface ECG recording in addition to receiving telemetry signals from the IMD is needed to perform pre-implant testing. Such full-function programmers can be bulky and costly to provide to all clinical centers.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an illustration of one type of IMD in which an embodiment of the invention may be implemented.
• FIG. 2 is an illustration of an alternative IMD with which the invention may be practiced.
• FIG. 3 is a functional block diagram representing components that may be included in an IMD electronics module along with associated memory.
• FIG. 4A is a block diagram providing an overview of an IMD packaging system including an electrical interface according to various embodiments of the invention.
• FIG. 4B is a diagram of an IMD packaging system wherein an electrical interface is provided in the form of a flexible circuit.
• FIG. 5 is a perspective view of one type of sterilizable package that may be used in various embodiments of the invention.
• FIG. 6A is a side cut-away view of one embodiment of a packaging system including an electrical interface used for accessing IMD electronics while the IMD is contained within a sterile package.
• FIG. 6B is a side, sectional view of an alternative embodiment of packaging system including a pressure generating member for promoting reliable electrical contact between an electrical interface and an IMD enclosed in a sterile package.
• FIG. 6C shows apressure generating member121 packaged within an inner tray, around an IMD and electrical interface for promoting good electrical contact between the IMD and electrical interface.
• FIG. 7 is a top view of the packaging system shown inFIG. 6A.
• FIG. 8 is a partial, side, cut-away view of an IMD packaging system according to an alternative embodiment of the invention wherein an electrical interface is formed on a substrate that includes a surface of the sterilizable package.
• FIG. 9 is a bottom view of the inner tray lid shown inFIG. 8.
• FIG. 10A is a top view of an alternative embodiment of a flexible circuit electrical interface formed on the inner surface of an inner tray lid.
• FIG. 10B is a top view of the flexible circuit shown inFIG. 10A after folding the flexible substrate along fold lines to provide insulation to the exterior portions of conductors.
• FIG. 10C is a top view of the electrical interface shown inFIG. 10B further including elements for protecting the electrical interface.
• FIG. 11 is a perspective view of an alternative embodiment of an electrical interface.
• FIG. 12 is a diagram of an alternative embodiment of an electrical interface used for connecting to IMD electronics while the IMD is within sterile packaging.
• FIG. 13 is a partial, side cut-away view of a packaging system according to another embodiment of the invention.
• FIG. 14 is a partial, side cut-away view of an electrical interface provided with a substrate that extends along the outer surface of a package tray lid.
• FIG. 15 is a plan view of an IMD in a sterilizable package provided with an interface for accessing IMD electronics according to another embodiment of the invention.
• FIG. 16 illustrates a bifurcated electrical interface.
DETAILED DESCRIPTION
• In the following description, references are made to illustrative embodiments for carrying out the invention. It is understood that other embodiments may be utilized without departing from the scope of the invention. For the purposes of illustration, various embodiments of the invention are described herein in the context of IMDs used to monitor cardiac function. Such IMDs may or may not include cardiac stimulation therapy delivery capabilities. Such devices include, for example, cardiac pacemakers, which may be used for delivering a wide variety of cardiac stimulation therapies including, for example, bradycardia pacing, cardiac resynchronization therapy, extra systolic stimulation, and anti-tachycardia pacing. Such devices further include cardiovertor/defibrillators, implantable ECG recorders, and implantable hemodynamic monitors.
• The scope of the invention is not limited, however, to devices configured to monitor cardiac signals. Aspects of the invention may be implemented in any IMD system in which electrical connection to the IMD electronics, prior to removing the IMD from sterilized packaging, is desired. Access to the IMD electronics may be desired for demonstration purposes, for verifying device functionality, or for performing pre-implant testing. Among the other types of IMDs in which aspects of the invention may be implemented are implantable drug pumps and neurostimulators, which are used for stimulating any portion of the central or peripheral nervous system. For example, neurostimulators may be used for controlling pain, reducing tremor, restoring muscle function, controlling incontinence, treating sleep apnea, treating digestive disorders or for vagal nerve stimulation for controlling cardiac function.
• FIG. 1 is an illustration of one type of IMD in which an embodiment of the invention may be implemented.IMD10 is shown as an implantable ECG recorder, also referred to as an implantable loop recorder (ILR).IMD10 is provided with ahousing12 for enclosing anelectronics module16 which controls device function and associatedmemory18 for storing ECG data.IMD10 includes two ormore electrodes14 incorporated onIMD housing12 which function as subcutaneous ECG electrodes for the recordation of ECG signals byIMD10.Electrodes14 are coupled to theinternal electronics module16 such that ECG signals may be sensed byelectrodes14 and stored inmemory18, typically in a continuously looping manner. Examples of implantable cardiac monitoring devices that may be used for recording ECG data, as well as other physiological data, are generally disclosed in U.S. Pat. No. 5,987,352 (Klein et al., Nov. 16, 1999), hereby incorporated herein by reference in its entirety.
• It can be appreciated that the selection of an implant site forIMD10 is important in ensuring that the ECG signal strength is adequate. Typically, pre-implant mapping is performed using an external ECG monitor connected to electrodes placed on the surface of the patient's skin to localize a site corresponding to the strongest ECG signal strength. Since theelectrodes14 incorporated on theIMD housing12 are relatively small compared to typical surface ECG electrodes, neonatal or pediatric-sized surface electrodes are commonly used to mimic the size and separation of thesubcutaneous electrodes14 onIMD housing12. However, even when the subcutaneous electrode size and spacing is closely represented by the surface electrodes used for pre-implant mapping, the electronics of the external ECG monitor may bear different mapping results than when the ECG measurements are taken directly using theIMD electronics module16.
• FIG. 2 is an illustration of an alternative IMD with which the invention may be practiced.IMD20 includes ahousing22 for enclosinginternal electronics16, and aconnector header24 for receiving leads26 disposed in operative relation to a patient's heart. Leads26 are illustrated as transvenous leads which generally carry endocardial electrodes at or near a distal lead end. A variety of lead configurations are available for use with an IMD, which may include one or more unipolar, bipolar, or multipolar leads carrying endocardial, epicardial, subcutaneous, or other types of electrodes and/or other physiological sensors such as blood pressure sensors, pH sensors, accelerometers, etc.
• Leads26 are each provided with a proximal connector assembly having connectors corresponding to each of the electrodes/sensors carried by the individual lead.Connector header24 includes electrical contacts which become electrically coupled to the lead connectors when the lead connector assembly is fully inserted in theconnector header24. Electrical contacts included inconnector header24 provide electrical connection between the lead connector assembly and theinternal IMD electronics16. Connection methods for connecting leads to an IMD are known in the art. An IMD may alternatively be provided with any combination of electrodes or sensors adapted for subcutaneous or non-subcutaneous implantation, either on the device housing as shown inFIG. 1 or carried by leads extending from the IMD, as generally illustrated inFIG. 2.
• FIG. 3 is a functional block diagram representing components that may be included in an IMD electronics module along with associated memory. An IMD, such asIMD10 orIMD20 shown inFIGS. 1 and 2 respectively, is generally provided with anelectronics module16 including timing andcontrol circuitry32 and an operating system that may employmicroprocessor30 or a digital state machine for timing sensing and therapy delivery functions in accordance with a programmed operating mode.Microprocessor30 and associatedmemory18 are coupled to the various components of the IMD via a data/address bus35. If the IMD is configured to deliver a therapy, atherapy delivery unit34 is provided which may include a pulse generator for delivering electrical stimulation or a drug reservoir and pump for delivering a drug therapy.Therapy delivery unit34 delivers therapies as needed under the control of timing andcontrol32. In the case of electrical stimulation therapies, such as cardiac stimulation therapies,therapy delivery unit34 is typically coupled to two ormore electrode terminals15, optionally via aswitch matrix36.Switch matrix36 may be used for selecting which electrodes and corresponding polarities are used for delivering electrical stimulation pulses. The appropriate number ofelectrode terminals15 is electrically coupled toelectronics module16 via feedthrough according to methods known in the art.Electrode terminals15 may be embodied aselectrodes14 incorporated in the housing of the IMD, as shown inFIG. 1, or contacts which become electrically coupled to lead connectors as described in conjunction withFIG. 2.
• Terminals15 may also be used for coupling electrodes used for sensing electrical signals within the body to theelectronics module16. With regard to thecardiac monitoring IMD10 shown inFIG. 1,electrode terminals15 are embodied assubcutaneous electrodes14 to deliver ECG signals to signalprocessor38. In other embodiments, combinations of multiple subcutaneous and/or cardiac electrodes may be used for acquiring multiple ECG vectors usingelectrode terminals15. Such signals may be stored inmemory18 on a continuous, periodic or triggered basis for use in diagnosing or monitoring a disease state. For example, in an ILR, heart rate and/or arrhythmia information may be determined from stored ECG signals. In devices that include therapy delivery capabilities, such asIMD20 ofFIG. 2, sensed cardiac electrical signals are also used for determining when an electrical stimulation therapy is needed and in controlling the timing of stimulation pulses.
• Electrodes used for sensing and electrodes used for stimulation may be selected viaswitch matrix36. When used for sensing,electrode terminals15 are coupled to signalprocessing circuitry38 viaswitch matrix36.Signal processor38 includes sense amplifiers and may include other signal conditioning circuitry and an analog to digital converter. Electrical signals may then be used bymicroprocessor30 for detecting physiological events, such as detecting and discriminating cardiac arrhythmias. In other embodiments, electrical signals sensed atelectrode terminals15 may be used for measuring impedance signals for monitoring edema, respiration or heart chamber volume.
• One or morephysiological sensors41 may optionally be included. Such sensors may include pressure sensors, accelerometers, impedance sensors, flow sensors, blood chemistry sensors, activity sensors or other physiological sensors known for use with IMDs.Sensors41 are coupled toelectronics module16 via asensor interface40 which provides sensor signals to signalprocessing circuitry38. Sensor signals are used bymicroprocessor30 for detecting physiological events or conditions. For example, an IMD may monitor heart wall motion, blood pressure, blood chemistry, respiration, or patient activity. Monitored signals may be used for sensing the need for delivering a therapy under control of the operating system.
• The operating system includes associatedmemory18 for storing a variety of programmed-in operating mode and parameter values that are used bymicroprocessor30. Thememory18 may also be used for storing data compiled from sensed physiological signals and/or relating to device operating history for telemetry transmission upon receipt of a retrieval or interrogation instruction. These functions and operations are known in the art, and are generally employed to store operating commands and data for controlling device operation and for later retrieval to diagnose device function or patient condition.
• Telemetry circuitry42 is typically provided to enable bidirectional communication between the IMD and an external programmer, home monitor, patient activator, or other external device, according to methods and apparatus known in the art. Programming commands or data are transmitted during uplink or downlink telemetry betweenIMD telemetry circuitry42 and external telemetry circuitry included in a programmer or monitoring unit. According to one embodiment of the invention, pre-implant test data is obtained using a packaging system that enables connection toelectronics module16 through a sterile IMD package. Pre-implant test data so obtained can be transmitted in real time, or at a delayed time, to an external monitor/programmer usingtelemetry circuitry42.Telemetry circuitry42 may correspond to telemetry systems known in the art, and may be configured for long-range telemetry communication with a monitor/programmer. Long-range telemetry systems are generally disclosed in U.S. Pat. No. 6,482,154 issued to Haubrich et al., incorporated herein by reference in its entirety.
• In some embodiments, analert unit44 is provided for generating an audible tone or sound. As will be described in greater detail below,electronics module16 may be used to perform pre-implant testing using a flexible circuit or other coupling appliance for connecting external electrodes toterminals15 without compromising the sterility of IMD within a sterile package.Microprocessor30 may process signals received atterminals15 for determining if implantation criteria are met or for identifying an optimal implantation location or orientation.Alert unit44 may be used to generate an audible tone or sound to indicate to a clinician that a particular test location or orientation meets or does not meet implant criteria or acceptable signal quality.
• It is recognized that the overall complexity ofelectronics module16 and other IMD components may vary depending on the functionality provided by the IMD. Functional units may be added or removed from the block diagram represented inFIG. 3 according to a particular application. For example,IMD10 shown inFIG. 1 may be used for ECG monitoring without therapy delivery capabilities in whichcase electronics module16 is provided withouttherapy delivery unit34. In other embodiments, a leadless IMD incorporating electrodes in the IMD housing may include pacing and/or cardioversion/defibrillation capabilities in which casetherapy delivery unit34 would include a low-voltage pulse generator and/or high-voltage capacitors with associated capacitor charging and high-voltage output circuitry as is known in the art.
• FIG. 4A is a block diagram providing an overview of an IMD packaging system according to various embodiments of the invention. Thepackaging system62 includes asterilizable package60 for containing anIMD10.Packaging system62 further includes anelectrical interface50 that allows electrodes or other sensors placed on or in a patient66 to be coupled toelectronics module16 whileIMD10 remains withsterilizable package60, without compromising the sterility ofIMD10.
• Electrical interface50 includespatient terminals54, signal/conduction transmission56, andpackage contacts52.Patient terminals54 may be in the form of electrodes adapted for placement directly on or inpatient66. Alternatively,patient terminals54 may be provided as connectors, such as snaps or clips, onto which electrodes or sensors placed on or inpatient66 may be attached using a cable, extension or lead. One ormore package contacts52 are electrically coupled to IMD electrode terminals15 (or sensor terminals41) included inIMD10 and thereby electrically coupled toelectronics module16. As described previously,IMD electrode terminals15 may be embodied as electrodes formed in or on the housing ofIMD10.IMD electrode terminals15 may alternatively be embodied as contacts used for electrically coupling lead-based electrodes and/or sensors toIMD10. The number of package contacts and corresponding patient terminals provided will depend on the application and may correspond to the total number of electrodes and sensors used by the IMD or a subset of electrodes and sensors used by the IMD.
• Electrical interface50 includes signal conduction/transmission56 which acts to convey signals received from the patient atpatient terminals54 to packagecontacts52, across asterile barrier61 ofpackage60. Signal conduction/transmission53, generally referred to as “conductor circuit” hereafter, may include conductors in the form of wires, foils, conductive tape, film or ink. However, it is recognized thatconductor circuit53 is not limited to include only conductive elements. In various embodiments,conductor circuit53 may include inductive elements, capacitive elements, antennas, optical fibers, or any other elements appropriate for conducting or transmitting a physiological signal received atpatient terminals54 to packagecontacts52. Alternatively, signals may be transmitted fromIMD electronics module16 topatient66 usingelectrical interface50. Depending on the type of sensors used byIMD10, electrical excitation signals may be required and transmitted to a sensor operatively positioned inpatient66 viaelectrical interface50. During some pre-implant testing, system tests or demonstration procedures, electrical pulses, for example stimulation pulses, may be transmitted fromelectronics module16 topatient terminals54.
• FIG. 4B is a diagram of an implantable medical device packaging system whereinelectrical interface50 is provided in the form of a flexible circuit that allows access to theIMD electronics module16 while theIMD10 is enclosed in asterilizable package60. The packaging system includeselectrical interface50 extending fromoutside sterilizable package60 to insidesterilizable package60.Electrical interface50 includes one ormore package contacts52 each coupled toindividual conductors56 included inconductor circuit53, and one or morepatient terminals54. Each ofconductors56 extend acrosssterile barrier61, between aninterior end59 coupled to apackage contact52 and anexterior end57 coupled to apatient terminal54.
• In the embodiment shown,package contact52 is disposed over asubcutaneous electrode14 located onIMD housing12 while the IMD remains inpackage60.Package contact52 makes electrical connection withelectrode14 thereby allowing electrical connection to the electronics contained inIMD10 usingpatient terminal54, located outside ofsterilizable package60. In various embodiments,package contact52 may be adapted for electrical coupling to any electrode or any electrode/sensor terminal or contact incorporated in or onIMD10.
• Sterilizable package60 is provided as a tray, pouch or other container for enclosing and maintaining sterility ofIMD10.Sterilizable package60 is typically sealed closed after receivingIMD10 to formsterile barrier61 and submitted to a sterilization method appropriate for the particular IMD contained therein, e.g., steam, gas, or ultrasonic sterilization.Electrical interface50 conveys electrical signals received atpatient terminals54 acrosssterile barrier61 without compromising the integrity of the sealedpackage60 or the sterility of theIMD10.
• Electrical interface50 may be fabricated as a flexible circuit using conductive ink (e.g., silver-silver chloride ink or a carbon-based ink) printed on a flexible,insulative substrate55 to formconductors56,package contacts52 andpatient contacts54. Alternatively, any ofconductors56,package contacts52 andpatient contacts54 may be formed by laminating or adhering electrically conductive materials in the form of wires, foils, film, or tape, ontoflexible substrate55. As will be described in greater detail below, in some embodimentsflexible substrate55 includes a portion ofsterilizable package60 whereinelectrical interface50 is formed on a surface ofpackage60.
• Patient terminals54 may be provided for direct placement on a patient's skin. Electrical body signals may then be provided toIMD10 viaelectrical interface50.Electrical interface50 is provided with a “neck”64 along whichconductors56 extend.Neck64 may be provided with any length to facilitate unencumbered placement ofpatient terminals54 on a patient. Alternatively,patient terminals54 may be embodied as coupling terminals or contacts to which electrode cables orextensions80 may be attached to thereby allow greater maneuverability and flexibility during pre-implant testing, without patient-to-IMD distance limitations.Electrode extensions80 may be standard surface electrode cables carrying surface electrodes82, which may be standard “off-the shelf” electrodes, adapted for placement on a patient's skin.
• Patient terminals54 may alternatively be adapted for electrical coupling to patient leads or lead extensions. For example,extensions80 may be provided with snaps, alligator clips, manufacturer-provided connectors, or other electrical connectors for facilitating electrical connection topatient terminals54 at one end of anextension80 and to a connector assembly of an implanted lead at the other end of anextension80.Extensions80 may be provided in a sterile condition to allow connection to implanted sterile leads. It is recognized that numerous configurations may be used for connectingpatient terminals54 to a patient, either directly or indirectly using extensions and/or leads, and such embodiments may include any number of electrodes and/or sensors positioned on or in the patient.
• Atemplate84 may be provided for guiding placement of surface electrodes82 to correspond to the separation distance ofIMD electrodes14. Alternatively,electrode extensions80 and surface electrodes82 may be custom components, provided withtemplate84 for mimicking the size and separation ofIMD electrodes14.Patient terminals54 may be provided as snaps, clips, or any other mechanism for mechanically and electricallycoupling electrode extensions80.Template84 may include labeling to indicate whichpatient terminals54 correspond to whichIMD electrode terminals15 and/orsensor terminals41.
• During pre-implant testing, signals obtained during placement ofpatient terminals54 at different body locations and orientations may be stored and analyzed byIMD10 for determining an optimal implant location. Alternatively or additionally,IMD10 may transmit signals received usingelectrical interface50 to an external programmer/monitor70 via atelemetry connection71.
• External programmer/monitor70 may correspond generally to programmer/monitors known in the art and typically includestelemetry circuitry72, a microprocessor-basedcontrol system74, adisplay76, and a user-interface78, which may be embodied as a graphical user interface.Display76 may be in the form of an LCD screen or other graphical or video display that allows a clinician to observe displayed signal data, for example ECG signals, whilepatient terminals54 are positioned at different body locations or orientations. The clinician may manually select an optimal implant location based on observed data.
• Alternatively, external programmer/monitor70 orIMD10 may analyze received signals using a programmed signal evaluation routine and automatically recommend an implant site or at least indicate when a location or orientation meets signal quality or other implant criteria. Such information can be displayed graphically or using text messages ondisplay76. Alternatively,display76 may be embodied as an LED display which indicates through color or number of LEDs illuminated acceptable on unacceptable signal quality. In yet another embodiment,display76 may include a speaker for broadcasting sound messages indicating acceptable or unacceptable signal quality. As described previously,alert circuitry44 may generate a signal indicating acceptable or unacceptable signal quality. A signal evaluation routine may determine signal features, signal-to-noise ratio, or other signal characteristics for determining if the signal quality meets predefined acceptance criteria.
• Display76 may further be used to prompt a clinician or other user to movepatient terminals54 to a number of body locations or orientations whileIMD10 and/or external monitor/programmer70 collects signal data corresponding to each location. The clinician or other user may useuser interface78 to indicate toIMD10 or external monitor/programmer70 whenpatient terminals54 are being moved to a new location and thereby indicate whenIMD10 or external monitor/programmer70 should begin a new signal evaluation routine. When multiple electrodes or sensors are available and coupled simultaneously toIMD10 usingpatient terminals54, theIMD10 may select different sensing vectors using switching circuitry36 (shown inFIG. 3), either automatically or in response to programmed-in commands.
• External programmer/monitor70 may vary in functionality and complexity in different embodiments. For example, in some embodiments, external programmer/monitor70 may receive signal data usingtelemetry circuit72, process signaldata using microprocessor74, and display pre-implant test results ondisplay76. External programmer/monitor70 may include a data storage module for printing or storing received data and/or test results electronically. In other embodiments, external programmer/monitor70 may be interfaced with a monitoring device94 used for displaying and/or storing signal data obtained usingelectrical interface50.
• In still other embodiments, external programmer/monitor70 may serve as a communication conduit betweenIMD10 and acomputerized database90.Database90 may be a web-based patient management system or implemented on a personal computer.Database90 is coupled to a communication network92, which may be a wireless network, enabling communication betweendatabase90 and external programmer/monitor70. Signal data received by external programmer/monitor70 is transmitted todatabase90 via communication network92. As such, signals obtained usingelectrical interface50, or test results based on such signals, may be transmitted directly todatabase90 for further analysis and/or viewing by a user.Database90 may be accessible on a local or remote computer, allowing pre-implant testing to be performed in a time and place independent manner.Database90 and external programmer/monitor70 may be provided according to known patient management systems, such as those generally disclosed in U.S. Pat. No. 6,250,309 (Krichen, et al.) and U.S. Pat. No. 6,622,045 (Snell et al.), both of which patents are incorporated herein by reference in their entirety.
• FIG. 5 is a perspective view of one type of sterilizable package that may be used in various embodiments of the invention.Package60 includes atray104, typically provided with acavity106 formed to match the contours of an IMD to be placed therein.Package tray104 has aninner surface110 and anouter surface111 which, in addition tocavity106, may form other cavities or recesses for containing accessories, tools or other components packaged with the IMD for use during implantation procedures.Tray104 is fabricated using thermoforming, injection molding or other appropriate processing of a material that withstands sterilization procedures used to sterilize the IMD contained therein and acts as a sterile barrier there after.Packaging tray104 is commonly fabricated from high-density polyethylene.
• Tray104 includes aseal area108 alonginner surface110 onto which atray lid102 is sealed after the IMD and any other package contents are placed intray104.Tray lid102 includes anouter surface105 and aninner surface103 and is commonly fabricated from coated paper or a high-density woven or non-woven polymer material.Tray lid102 andtray104 are typically sealed together alongseal area108 using an appropriate adhesive for forming a reliable sterile barrier. After undergoing sterilization,package60 is placed in any desired outer packaging, which is typically a box or carton provided with appropriate labeling. In some embodiments, the packaging system may include an outer tray and outer tray lid for containinginner tray104 sealed withinner tray lid102.Inner tray104 may be sterilized within the outer tray, and the outer tray is placed in the desired outer packaging.
• FIG. 6A is a side cut-away view of one embodiment of a packaging system including an electrical interface used for accessing IMD electronics while the IMD is contained within asterile package60.Sterile package60 includes aninner tray104 andouter tray114.IMD10 rests incavity106 ofinner tray104. Anelectrical interface50 in the form of aflexible circuit50 is placed overIMD10 such thatpackage contact52 is electrically coupled toIMD electrode14.Inner tray104 is sealed closed withinner tray lid102 alongseal area108.Inner tray104 is placed within atray cavity116 ofouter tray114.Outer tray114 is sealed closed withouter tray lid112 along outertray seal area118. Theneck64 ofelectrical interface50 is sealed betweeninner tray lid102 andinner tray104 and betweenouter tray lid112 andouter tray114 and extends outside ofpackage60.Patient terminals54 are located at the exterior ends57 ofconductors56 extending alongneck64.Patient terminals54 are thus available outside ofpackage60 for use in coupling a patient to the electronics module contained withinIMD10, without compromising the sterility ofIMD10 withinpackage60.
• The depth ofIMD cavity106 ininner tray104 is dimensioned appropriately to causeelectrode14 to come into contact withpackage contact52 when thepackaging system62 is assembled. To promote reliable coupling betweenpackage contact52 andIMD electrode14, thethickness115 ofsubstrate55, at least in the area ofpackage contact52, is provided to create pressure betweencontact52 andIMD electrode14.Package contacts52 may be formed as blisters or buttons, having a generally hemispherical shape, for example, which protrudes fromflexible circuit substrate55 to thereby promote reliable electrical contact withIMD electrodes14.
• Additionally or alternatively, acompressible element120 may be included or incorporated ininner tray104. Physical contact betweenpackage contact52 andIMD electrode14 should be adequate to create an electrical connection betweencontact52 andelectrode14 without causing mechanical damage toelectrode14. As shown,compressible element120, which may be embodied as a compressed foam member, is placed between theinner surface110 ofinner tray104 andIMD10.Compressible element120 generates pressure betweenIMD electrode14 andpackage contact52 to promote reliable electrical contact there between.Compressible element120 could alternatively be positioned between theinner surface103 ofinner tray lid102 andelectrical interface50 or along theouter surface105 ofinner tray lid102, betweeninner tray lid102 andouter tray lid112.Compressible element120 may alternatively be enclosed in an outercarton containing package60 and positioned to generate pressure in the area ofpackage contact52 andIMD electrode14.
• FIG. 6B is a side, sectional view of an alternative embodiment of packaging system including apressure generating member121 for promoting reliable electrical contact betweenelectrical interface50 andIMD10 enclosed insterile package60. InFIG. 6B,pressure generating member121 is provided as a generally U-shaped clip having aclosed side119 and anopen side117.Pressure generating member121 is adapted for positioning around the outside ofouter tray114 andouter tray lid118 to generate positive pressure in the area ofpackage contact52 andIMD electrode14 to promote good electrical contact there between.
• Pressure generating member121 may be packaged in an outer carton along withsterile package60 and placed in the position shown inFIG. 6B by a user as needed at the time of testing. Alternatively,pressure generating member121 may be packaged withsterile package60 already positioned aroundsterile package60 as shown inFIG. 6B. In other embodiments,pressure generating member121 may be positioned withinouter tray114, aroundinner tray104 andinner tray lid102 to promote good electrical contact betweenpackage contact52 andIMD electrode14.Pressure generating member121 could alternatively be packaged withininner tray104, aroundIMD10 andelectrical interface50 as shown inFIG. 6C. In this embodiment,electrical interface50 would not be sealed along its entire periphery betweeninner tray lid102 andinner tray104 in order to allowpressure generating member121 to be fitted over one side or end ofelectrical interface50 as shown.Pressure generating member121 may also act to stabilize the position ofelectrical interface50 relative toIMD10.
• Pressure generating member121 may be formed of a relatively rigid polymeric or metal material which may be flexible alongclosed side119 to allowopen side117 to be opened wider to enablemember121 to be slid over the outside of sterile package60 (orinner tray104 andtray lid102 orIMD10 and electrical interface50). It is recognized that pressure-generatingmember121 may be provided in numerous configurations for promoting good contact betweenelectrical interface50 andIMD10. For example,pressure generating member121 may alternatively be formed having a “clam-shell” shape, having a hinged or spring-loaded side or sides, or having latching mechanisms.Pressure generating member121 may be used alone or in combination withcompressible element120.Pressure generating member121 and/orcompressible element120 may be designed to create a predetermined, constant pressure at the contact point betweenIMD10 andelectrical interface50.
• FIG. 7 is a top view of the packaging system shown inFIG. 6A.Electrical interface50 includes aflexible substrate55 that may be formed to match the outer contours of theinner tray104.Substrate55 becomes sealed betweeninner tray104 and inner tray lid102 (shown inFIG. 6A) along theentire seal area108. Providingsubstrate55 along theentire seal area108 may prevent thickness differentials alongseal area108 that might otherwise leave discreet openings along theseal area108 which could lead to contamination of the inner tray contents. Alternativelysubstrate55 may be formed such thatsubstrate55 is sealed betweeninner tray104 andinner tray lid102 along any portion ofseal area108, as long as a reliable seal is formed betweentray104 andtray lid102 for maintaining sterility ofIMD10 and any other packaged components. Generally,substrate55 will be sealed betweentray104 andlid102 at least along the area whereneck64 ofelectrical interface50 traversesinner seal area108
• Conductors56 may be insulated by adielectric layer124 formed overconductors56.Dielectric layer124 may additionally extend over any portion or all ofsubstrate55, while leavingpackage contacts52 andpatient contacts54 exposed.Dielectric layer124 may extend over the entire innertray seal area108 to promote a uniform, reliable seal.Dielectric layer124 may be formed from any dielectric polymeric material including polyesters, ethylene-vinyl acetate copolymers, terpolymers such as acrylonitrile-butadiene styrene, or polyvinyl chloride and its copolymers. Alternatively,conductor circuit53 may include shielded conductors and contacts to protect the IMD and/or patient from electrical noise.
• The exterior end ofsubstrate55 may be formed into atemplate84 upon whichpatient contacts54 are mounted.Template84 corresponds to the size and shape ofIMD10 withpatient contacts54 sized and spaced relative to one another to mimic the size and spacing ofIMD electrodes14. Once an optimal implant site is identified through pre-implant testing, the site may be marked or traced usingtemplate84.Template84 may be provided havingstencil openings122 to facilitate marking a selected implant site on a patient.
• InFIG. 7,conductor circuit53 is shown to includeLEDs128 along eachconductor56.LEDs128 may be used to indicate that an electrical circuit has been completed and signals received atpatient terminals54 are being conducted toIMD10. In some embodiments, theIMD10 may transmit signals topatient terminals54, such as sensor excitation signals or electrical stimulation pulses. As such,LEDs128 may be used to indicate that electrical signals fromIMD10 are being conducted topatient terminals54.
• After completing pre-implant testing, the outer tray lid may be removed fromouter tray114.Neck64 ofelectrical interface50 may be provided with notches orperforations126 to facilitate tearing of theelectrical interface50 just outside ofinner tray104. Tearing ofelectrical interface50 allowsinner tray104 to be removed fromouter tray114 without hindrance due to attachment ofelectrical interface50 toouter tray114 along outertray seal area118.
• FIG. 8 is a partial, side, cut-away view of an IMD packaging system according to an alternative embodiment of the invention wherein an electrical interface is formed on a substrate that includes a surface of the sterilizable package. In this example,inner surface103 ofinner tray lid102 serves as a substrate forelectrical interface50. In this embodiment,conductors56 andpackage contacts52 are shown printed or laminated toinner surface103 ofinner tray lid102.Conductors56 may be insulated by adielectric layer124.
• FIG. 9 is a bottom view of the inner tray lid shown inFIG. 8.Tray lid102 is provided with a shape that mates with theseal area108 of inner tray104 (shown inFIG. 5) and serves as a substrate forelectrical interface50.Inner tray lid102 is formed withneck64 extending there from withpatient terminals54 coupled to the exterior ends57 ofconductors56.Inner tray lid102 may be fabricated from paper or a high-density, woven or non-woven polymer, such as a high-density polyethylene.Conductors56,patient terminals54 andpackage contacts52 may be printed oninner tray lid102 using a conductive ink or may be provided as foil, tape, film conductive material laminated totray lid102. In some embodiments, theinner surface103 ofinner tray lid102, or any other substrate onto whichelectrical interface50 is formed, may be bonded or treated with a coating to promote good adhesion of the conductive material on the substrate. Thetray lid102 is coated with an adhesive alongseal area108 for sealinglid102 toinner tray104.
• FIG. 10A is a top view of an alternative embodiment of an electrical interface formed on the inner surface of an inner tray lid. Thesubstrate55 is formed withlateral flaps130 alongneck64 which can be folded alongfold lines132 overelongated conductors56 thereby providing insulation toconductors56.Lateral flaps130 are formed havingpatient electrode windows134 such that whenlateral flaps130 are folded alongfold lines132, patient electrodes are exposed and not insulated bylateral flaps130. Aportion136 ofneck64 corresponding to theseal area108 of an outer tray, when used, is provided without lateral flaps130. The portions ofconductors56 that become enclosed withininner tray104, innertray seal area108, and outertray seal area118 may not need to be insulated and may remain exposed.FIG. 10B is a top view of the electrical interface shown inFIG. 10A after foldingsubstrate55 alongfold lines132 to provide insulation to the portions ofconductors56 which will be located outside of an outer tray.
• FIG. 10C is a top view of the electrical interface shown inFIG. 10B further including elements for protecting the electrical interface. In some embodiments, a removable patientterminal insulator137 may be provided for protectingpatient terminals54 from mechanical damage or wear and/or to prevent unwanted electrical signals to be coupled through to the IMD electronics viaterminals54. Removable patientterminal insulator137 may be provided, for example, in the form of a removable tape that is pulled away to expose patient terminals at the time of pre-implant testing or other use ofelectrical interface50. Patientterminal insulator137 may be provided as a replaceable element such that after testing is completed,insulator137 may be placed back overpatient terminals54.
• A removableshort circuit element138 may be provided acrossconductors56 so as to prevent unwanted electrical signals from reaching the IMD electronics.Short circuit element138 may be provided, for example, as a strip of conductive tape extending acrossconductors56 which can be removed at the appropriate time to enable pre-implant testing or other use ofelectrical interface50.Short circuit element138 may be provided as a replaceable element such that after testing is completed,short circuit element138 can be put back in place to create a short acrossconductors56.
• FIG. 11 is a perspective view of an alternative embodiment of an electrical interface.Substrate55 is provided with a singlelateral flap130 alongneck64 sized to cover and insulateconductors56 after foldinglateral flap130 along foldingline132.Windows134 are provided inlateral flap130 such thatpatient terminals54 remain exposed after foldinglateral flap130 overconductors56. Lateral flap(s)130 as shown inFIGS. 10B and 11 may be laminated toneck64 or sealed toneck64 using the same method for sealinginner tray lid102 to an inner tray. InFIG. 11,patient terminals54 are shown to includeconnection members135, which may be in the form of snaps or clips, to facilitate connection of electrode leads or cable extensions as described previously.
• WhileFIGS. 8 through 11 depictelectrical interface50 formed on an inner surface ofinner tray lid102, it is recognized thatelectrical interface50 may be formed on any inner surface ofpackage60 so long aspackage contacts52 become electrically coupled toIMD electrodes14. For example, in some embodiments, the IMD may be configured and contained within an inner tray such that contact with an electrode terminal15 (shown inFIG. 4A) is best made from an inner surface of the inner tray rather than the tray lid. In such a configuration,package contact52 and a portion of theconductor circuit53 may be formed on an inner surface of the inner tray instead of the tray lid.
• FIG. 12 is a diagram of an alternative embodiment of an electrical interface used for connecting to IMD electronics while the IMD is within sterile packaging.Conductor circuit53 includesconductors56 andcapacitive elements140 used to conduct signals acrossseal area108 ofpackage60. It is recognized thatconductive circuit53 may include any circuitry used to convey signals sensed usingpatient terminals54 to packagecontacts52. Acapacitive element140 may be used to conduct signals across a sterile barrier ofpackage60. The inner tray wall or theseal area108 may serve as a dielectric in thecapacitive element140. Aconductor circuit53 including acapacitive element140 may protect the patient and/or IMD from noise or signal baseline variation that may be induced onconductors56.
• FIG. 13 is a partial, side cut-away view of a packaging system according to another embodiment of the invention.Package60 includes sterilizableinner tray104 containingIMD10 havingsubcutaneous electrode14.Inner tray104 is sealed closed alongseal area108 withtray lid102.Tray lid102 serves as the substrate forelectrical interface50 includingpackage contact52 positioned to provide electrical contact withelectrode14.Electrical interface50 further includeselongated conductors56 as shown previously extending topatient terminal54.Electrical interface50 is shown in a folded arrangement over anouter tray lid112 sealed toouter tray114, containinginner tray104. Anouter carton150 is provided for containingouter tray114 andelectrical interface50.
• Astrain relief member165 is shown inFIG. 13 extending fromneck64 to an outer surface ofouter tray114.Strain relief member165 may be coupled to any portion ofpackage60 to provide strain relief to the portion ofneck64crossing seal areas118 and108.Strain relief member165 may prevent inadvertent breach of the outer tray seal or inner tray seal whenpatient terminals54 are being attached or repositioned on a patient.
• Outer carton150 has aninner surface154 and anouter surface152 which form arecess156 in which a carton contact160 is mounted on acompressible member162. When carton contact160 is pressed down, carton contact160 makes electrical contact withpatient terminal54. Carton contact160 may be provided with a snap or clip member to facilitate attaching an external electrode extension or cable. Connection to the electronics withinIMD10 is thereby made possible via carton electrode160 andelectrical interface50 whileIMD10 remains inside sterilizedinner tray104,outer tray114 andouter carton150. It is recognized that in various embodiments, other signal conveying elements may be added to or substituted for carton electrode160, such as capacitive elements, inductive elements, optical fibers, or antennas.
• Carton150 may be formed with a closingmember158, such as a closable flap or resealable tape that can be closed overrecess156 to protect carton electrode160. It is recognized that numerous configurations may be conceived for incorporating a carton electrode160 inouter carton150. For example, in other embodiments, carton electrode160 may be located alongouter surface152 extending through toinner surface154 without being positioned in arecess156. It is further recognized that a removable insulating layer may be provided over carton electrode160. In some embodiments,compression member162 may not be provided, and the normal position of carton contact160 may be in electrical contact withpatient terminal54. An insulating material over carton contact160 may or may not be used.
• FIG. 14 is a partial, side cut-away view of anelectrical interface50 provided with asubstrate55 that extends along theouter surface105 oftray lid102.Electrical interface50 includes apackage contact52 formed extending throughtray lid102 to make electrical contact with IMDsubcutaneous electrode14. In an alternative embodiment, aseparate substrate55 is not used andelectrical interface50 is formed on theouter surface105 oftray lid102.Conductor56 would extend along tray lidouter surface105 to packagecontact52 which would extend throughtray lid102 to make electrical contact withIMD electrode14. Alternatively, elongatedconductor56 may extend throughtray lid102.Conductor56 may be provided as a conductive wire, foil, or film that penetratestray lid102 or may include an capacitive or inductive element for conveying current acrosstray lid102. It is recognized that in various embodiments, any element ofelectrical interface50 may extend across a sterile barrier, i.e., from an outer surface to an inner surface of a sterilizable IMD package, along any portion of the package and is not limited to extending across a seal area of the package.
• Furthermore, theelectrical interface50 may be formed on a substrate extending along any outer or inner surface of the sterilizable IMD package, including an outer or inner surface of any tray, tray lid, pouch or other sterilizable IMD package. Alternatively,electrical interface50 may be fabricated using aseparate substrate55, which likewise may extend along any outer or inner surface of the sterilizable IMD package. The exact configuration ofelectrical interface50 with respect to theIMD package60 may vary from embodiment to embodiment depending on the orientation of the IMD within the package and the resulting location of IMD electrodes or electrode terminals with which package contact(s)52 are to be electrically coupled.
• FIG. 15 is a plan view of an IMD in a sterilizable package provided with an electrical interface for accessing IMD electronics according to another embodiment of the invention. Some IMDs may be used in conjunction with electrodes carried by leads extending from the IMD rather than being incorporated on the IMD housing.IMD20 is shown havingconnector header24 provided with aconnector bore200 adapted for receiving a connector assembly of a lead carrying one or more electrodes or other sensors. Connector header and lead connector assembly configurations are known in the art. In the example shown, connector bore200 is provided withcontacts202 and204 for coupling with connectors included on a lead connector assembly.
• To facilitate electrical connection toelectrical interface50,IMD20 may be packaged withinsterilizable package60 with aconnector appliance210 inserted intoconnector bore200.Connector appliance210 is provided with aconnector assembly212 adapted for insertion intoconnector bore200.Connector assembly212 includes twoconnectors214 and215 separated by an insulatingsegment216.Connectors214 and215 align with and become electrically coupled tocontacts202 and204 whenconnector assembly212 is fully inserted inconnector bore200.Connector assembly212 ofconnector appliance210 generally corresponds to a connector assembly provided on a lead intended for use withIMD20.Connector appliance210 is provided withelectrode contacts220 which are separately coupled to each ofconnectors214 and215 by conductors217 extending throughappliance210.Package contacts52 included onelectrical interface50 are positioned overelectrode contacts220 such thatpatient terminals54, located outside ofpackage60, can be coupled to the electronics included inIMD20 viaconnector appliance210. Alternatively, conductors217 may extend along a substrate to the outside ofpackage60 directly topatient terminals54, without the use ofpackage contacts52.
• Patient terminals54 may be positioned on or in a patient or coupled to electrodes or any other physiological sensors positioned on or in a patient via appropriate leads or extension cables. As such,electrical interface50 may be used to access IMD electronics included in an IMD having aconnector header24 with the use of aconnector appliance210.
• FIG. 16 illustrates a bifurcated electrical interface. In some embodiments, two or more electrodes carried by branching or separate leads may be placed independently of each other. Anelectrical interface50 may be provided with abifurcation230 such thatpatient terminals54 may be placed at separate, spaced apart locations. It is recognized thatsubstrate55 may be provided with numerous shapes or configurations for allowing placement ofpatient terminals54 during pre-implant testing in any appropriate manner that mimics placement of the actual electrodes to be used in conjunction with the IMD. Alternatively,patient terminals54 may be connected to separate electrode extensions that allow unencumbered placement of electrodes on the patient during pre-implant testing, as described previously.
• For the sake of illustration, various embodiments described herein have generally related to an electrical interface that allows connection to IMD electronics for pre-implant testing relating to optimizing subcutaneous electrode placement. However, it is recognized that an electrical interface used to access the electronics within an IMD still contained in a sterile package may be designed to mimic electrodes/sensors adapted for other implant locations, e.g., epicardial, endocardial, sub-muscular, or otherwise. As such, embodiments that include using an electrical interface for testing non-subcutaneous implant locations of an IMD or electrodes/sensors are included in the scope of the invention. Pre-implant testing using the interface may be performed to determine if the patient meets implant criteria and/or selecting an optimal implant site.
• Various embodiments of theelectrical interface50 shown inFIG. 4A have been described primarily in the context of an interface used to couple electrodes, for example ECG electrodes, to an IMD electronics module across a sterile barrier. However, theelectrical interface50 may be used to couple any type and number of electrodes and/or sensors to the IMD electronics. Furthermore,electrical interface50 may be used for purposes other than pre-implant testing.Electrical interface50 may be used, for example, for performing IMD system tests or for demonstration purposes.
• Packaging systems having an interface that allows access to IMD electronics across a sterile barrier have been presented in the foregoing description with reference to specific embodiments. It is appreciated that various modifications to the referenced embodiments may be made without departing from the scope of the invention as set forth in the following claims.

Claims (23)

1. A system, comprising:

a sterilizable package;

an implantable medical device placed inside the sterilizable package; and

means for conveying a physiological signal to the implantable medical device within the sterilizable package without breaching the implantable medical device sterility.

2. The system ofclaim 1 wherein the implantable medical device includes a sensor terminal and the conveying means includes means for making electrical contact with the sensor terminal.

3. The system ofclaim 2 wherein the implantable medical device sensor terminal is adapted for coupling to any of: an electrode, a blood pressure sensor, an accelerometer, a blood chemistry sensor.

4. The system ofclaim 1 wherein the conveying means includes means for receiving the physiological signal.

5. The system ofclaim 1 wherein the means for receiving the physiological signal includes means for connecting a medical sensor operatively disposed in or on a patient to the receiving means.

6. The system ofclaim 1 wherein the conveying means includes any of: an inductive element, a capacitive element, an antenna, and an optical fiber.

7. The system ofclaim 1 wherein the conveying means includes a flexible substrate and, disposed on the flexible substrate, any of: conductive ink, conductive foil, conductive film, and conductive tape.

8. The system ofclaim 1 further including means for transmitting signals received by the implantable medical device from the conveying means to an external device.

9. The system ofclaim 1 further including:

a computerized database;

a communication network coupled to the database;

means for transmitting data from the implantable medical device to the database via the communication network.

10. The system ofclaim 1 wherein further including means for processing signals received by the implantable medical device using the conveying means.

11. The system ofclaim 10 wherein the implantable medical device further includes means for generating an signal corresponding to signals received by the implantable medical device using the conveying means.

12. The system ofclaim 1 wherein the sterilizable package includes an inner surface and an outer surface and wherein the conveying means is formed on a portion of any of: the inner surface and outer surface.

13. The system ofclaim 1 wherein the sterilizable package includes a device tray and a tray lid sealed to the device tray.

14. The system ofclaim 1 further including means for generating pressure for promoting electrical contact between the conveying means and the implantable medical device.

15. The system ofclaim 1 wherein the conveying means includes a template corresponding to the shape of the implantable medical device.

16. The system ofclaim 15 wherein the template includes means for facilitating marking a selected implant arrangement.

17. The system ofclaim 1 wherein the implantable medical device includes a connector header having electrical contacts disposed in a connector bore, and the conveying means includes means for electrically coupling the conveying means to the connector bore electrical contacts.

18. The system ofclaim 1 wherein the conveying means includes a means for insulating any portion of the conveying means.

19. The system ofclaim 1 wherein the conveying means includes means for creating a short circuit across the conveying means for protecting the implantable medical device from electrical signals when the conveying means is not in use.

20. The system ofclaim 1 wherein the conveying means includes means for relieving mechanical strain across the conveying means.

21. The system ofclaim 1 further including an outer carton containing the sterilizable package means for electrically coupling to the conveying means from outside of the outer carton.

22. The system ofclaim 1 wherein the conveying means includes means for indicating electrical signal conduction by the conveying means.

23. An electrical interface that allows electrical coupling to an implantable medical device placed inside a sterilizable package without breaching the sterility of the sterilizable package, comprising:

package contacts in electrical contact with the implantable medical device;

patient terminals positioned outside the sterilizable package; and

a conductor circuit extending between the package contacts and the patient terminals.

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