WO2005102447A1 - Derivation implantable sure pour l'irm - Google Patents

Derivation implantable sure pour l'irm Download PDF

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Publication number
WO2005102447A1
WO2005102447A1 PCT/US2004/042081 US2004042081W WO2005102447A1 WO 2005102447 A1 WO2005102447 A1 WO 2005102447A1 US 2004042081 W US2004042081 W US 2004042081W WO 2005102447 A1 WO2005102447 A1 WO 2005102447A1
Authority
WO
WIPO (PCT)
Prior art keywords
medical lead
jacket
lead according
lead
conductive
Prior art date
Application number
PCT/US2004/042081
Other languages
English (en)
Inventor
Carl D. Wahlstrand
Robert M. Hrdlicka
Thomas E. Cross, Jr.
Thomas Barry Hoegh
James M. Olsen
Stephen L. Bolea
Original Assignee
Medtronic, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/993,195 external-priority patent/US7844344B2/en
Application filed by Medtronic, Inc. filed Critical Medtronic, Inc.
Publication of WO2005102447A1 publication Critical patent/WO2005102447A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0551—Spinal or peripheral nerve electrodes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0526—Head electrodes
    • A61N1/0529—Electrodes for brain stimulation
    • A61N1/0534—Electrodes for deep brain stimulation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
    • A61N1/3606—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for a particular treatment
    • A61N1/36071—Pain
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0551—Spinal or peripheral nerve electrodes
    • A61N1/0553—Paddle shaped electrodes, e.g. for laminotomy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/08—Arrangements or circuits for monitoring, protecting, controlling or indicating
    • A61N1/086—Magnetic resonance imaging [MRI] compatible leads
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362—Heart stimulators
    • A61N1/37—Monitoring; Protecting
    • A61N1/3718—Monitoring of or protection against external electromagnetic fields or currents

Definitions

  • the present invention generally relates to implantable medical devices, and more particularly to an implantable MRI-safe lead including a conductive jacket for dissipating or directing induced RF energy to a patient's body so as to reduce the generation of unwanted heat at the lead's stimulation electrodes.
  • Implantable medical devices are commonly used today to treat patients suffering from various ailments. Such implantable devices may be utilized to treat conditions such as pain, incontinence, sleep disorders, and movement disorders such as Parkinson's disease and epilepsy. Such therapies also appear promising in the treatment of a variety of psychological, emotional, and other physiological conditions.
  • One known type of implantable medical device a neurostimulator, delivers mild electrical impulses to neural tissue using an electrical lead.
  • electrical impulses may be directed to specific sites.
  • Such neurostimulation may result in effective pain relief and a reduction in the use of pain medications and/or repeat surgeries.
  • SCS Spinal Cord Stimulation
  • DBS Deep Brain Stimulation
  • An SCS stimulator may be implanted in the abdomen, upper buttock, or pectoral region of a patient and may include at least one extension running from the neurostimulator to the lead or leads which are placed somewhere along the spinal cord.
  • Each of the leads currently contains from one to eight electrodes.
  • Each extension (likewise to be discussed in detail below) is plugged into or connected to the neurostimulator at a proximal end thereof and is coupled to and interfaces with the lead or leads at a distal end of the extension or extensions.
  • the implanted neurostimulation system is configured to send mild electrical pulses to the spinal cord. These electrical pulses are delivered through the lead or leads to regions near the spinal cord or the nerve selected for stimulation.
  • Each lead includes a small insulated wire coupled to an electrode at the distal end thereof through which the electrical stimulation is delivered.
  • the lead also comprises a corresponding number of internal wires to provide separate electrical connection to each electrode such that each electrode may be selectively used to provide stimulation. Connection of the lead to an extension may be accomplished by means of a connector block including, for example, a series or combination of set-screws, ball-seals, etc.
  • a DBS system comprises similar components (i.e. a neurostimulator, at least one extension, and at least one stimulation lead) and may be utilized to provide a variety of different types of electrical stimulation to reduce the occurrence or effects of Parkinson's disease, epileptic seizures, or other undesirable neurological events.
  • the neurostimulator may be implanted into the pectoral region of the patient.
  • the extension or extensions may extend up through the patient's neck, and the leads/electrodes are implanted in the brain.
  • the leads may interface with the extension just above the ear on both sides of the patient.
  • the distal end of the lead may contain from four to eight electrodes and, as was the case previously, the proximal end of the lead may connect to the distal end of the - extension and held in place by set screws.
  • the proximal portion of the extension plugs into the connector block of the neurostimulator.
  • Magnetic resonance imaging is a relatively new and efficient technique that may be used in the diagnosis of many neurological disorders. It is an anatomical imaging tool which utilizes non-ionizing radiation (i.e. no x-rays or gamma rays) and provides a non- invasive method for the examination of internal structure and function.
  • MRI permits the study of the overall function of the heart in three dimensions significantly better than any other imaging method.
  • imaging with tagging permits the non- invasive study of regional ventricular function.
  • MRI scanning is widely used in the diagnosis of diseases and injuries to the head.
  • the MRI is now considered by many to be the preferred standard of care, and failure to prescribe MRI scanning can be considered questionable. For example, approximately sixteen million MRIs were performed in 1996 followed by approximately twenty million in the year 2000. It is projected that forty million MRIs will be performed in 2004.
  • a magnet creates a strong magnetic field which aligns the protons of hydrogen atoms in the body and then exposes them to radio frequency (RF) energy from a transmitter portion of the scanner. This spins the various protons, and they produce a faint signal that is detected by a receiver portion of the scanner.
  • RF radio frequency
  • a computer renders these signals into an image.
  • three electromagnetic fields are produced; i.e. (1) a static magnetic field, (2) a gradient magnetic field, and (3) a radio frequency (RF) field.
  • the main. or static magnetic field may typically vary between 0.2 and 3.0 Tesla.
  • a nominal value of 1.5 Tesla is approximately equal to 15,000 Gauss which is 30,000 times greater than the Earth's magnetic field of approximately 0.5 Gauss.
  • the time varying or gradient magnetic field may have a maximum strength of approximately 40 milli- Tesla/meter at a frequency of 0-5 KHz.
  • the RF may, for example, produce thousands of watts at frequencies of between 8-128 MHz. For example, up to 20,000 watts may be produced at 64 MHz and a static magnetic field of 1.5 Tesla; that is, 20 times more power than a typical toaster.
  • questions have arisen regarding the potential risk associated with undesirable interaction between the MRI environment and the above-described neurostimulation systems; e.g. forces and torque on the implantable device within the MRI 'scanner caused by the static magnetic field, RF-induced heating, induced currents due to gradient magnetic fields, device damage, and image distortion.
  • a medical lead configured to be implanted into a patient's body and having at least one distal stimulation electrode and at least one conductive filer electrically coupled to the distal stimulation electrode.
  • a jacket is provided for housing the conductive filer and for providing a path distributed along at least a portion of the length of the lead for guiding induced RF energy from the filer to the patient's body.
  • FIG. 1 illustrates a typical spinal cord stimulation system implanted in a patient
  • FIG. 2 illustrates a typical deep brain stimulation system implanted in a patient
  • FIG. 3 is an isometric view of the distal end of the lead shown in FIG. 2;
  • FIG. 4 is an isometric view of the distal end of the extension shown in FIG. 2;
  • FIG. 5 is an isometric view of an example of a connector screw block suitable for connecting the lead of FIG. 3 to the extension shown in FIG. 4;
  • FIG. 6 is a top view of the lead shown in FIG. 2;
  • FIGs. 7 and 8 are cross-sectional views taken along lines 7-7 and 8-8, respectively, in FIG. 6;
  • FIG. 9 is a top view of an alternate lead configuration
  • FIGs. 10 and 11 are longitudinal and radial cross-sectional views, respectively, of a helically wound lead of the type shown in FIG. 6;
  • FIGs. 12 and 13 are longitudinal and radial cross-sectional views, respectively, of a cabled lead
  • FIG. 14 is an exploded view of a neurostimulation system
  • FIG. 15 is a cross-sectional view of the extension shown in FIG. 14 taken along line 15-15;
  • FIGS. 16-19 are schematic diagrams of potential lossy lead configurations
  • FIGs. 20 and 21 are longitudinal and cross-sectional views, respectively, of a first embodiment of the inventive lead
  • FIGs. 22 and 23 are longitudinal and cross-sectional views, respectively, of a further embodiment of the present invention.
  • FIGS. 24-30 illustrate still further embodiments of the present invention.
  • FIGs. 31-34 are isometric and cross-sectional views illustrating a still further embodiment of the present invention.
  • FIGs. 35 and 36 are isometric and cross-sectional views, respectively, of yet another embodiment of the present invention.
  • FIGs. 37 and 38 illustrate still further embodiments of the present invention.
  • FIG. 39 is an isometric view of yet another embodiment of the present invention.
  • FIG. 1 illustrates a typical SCS system implanted in a patient.
  • the system comprises a pulse generator such as a SCS neurostimulator 20, a lead extension 22 having a proximal end coupled to neurostimulator 20 as will be more fully described below, and a lead 24 having a proximal end coupled to the distal end of extension 22 and having a distal end coupled to one or more electrodes 26.
  • Neurostimulator 20 is typically placed in the abdomen of a patient 28, and lead 24 is placed somewhere along spinal cord 30.
  • neurostimulator 20 may have one or two leads each having four to eight electrodes.
  • Such a system may also include a physician programmer and a patient programmer (not shown).
  • Neurostimulator 20 may be considered to be an implantable pulse generator of the type available from Medtronic, Inc. and capable of generating multiple pulses occurring either simultaneously or one pulse shifting in time with respect to the other, and having independently varying amplitudes and pulse widths.
  • Neurostimulator 20 contains a power source and the electronics for sending precise, electrical pulses to the spinal cord to provide the desired treatment therapy. While neurostimulator 20 typically provides electrical stimulation by way of pulses, other forms of stimulation may be used such as continuous electrical stimulation.
  • Lead 24 is a small medical wire having special insulation thereon and includes one or more insulated electrical conductors each coupled at their proximal end to a connector and to contacts/electrodes 26 at its distal end.
  • Lead 24 may contain a paddle at its distant end for housing electrodes 26; e.g. a Medtronic paddle having model number 3587A.
  • electrodes 26 may comprise one or more ring contacts at the distal end of lead 24 as will be more fully described below.
  • lead 24 is shown as being implanted in position to stimulate a specific site in spinal cord 30, it could also be positioned along the peripheral nerve or adjacent neural tissue ganglia or may be positioned to stimulate muscle tissue. Furthermore, electrodes/contacts 26 may be epidural, intrathecal or placed into spinal cord 30 itself. Effective spinal cord stimulation may be achieved by any of these lead placements. While the lead connector at proximal end of lead 24 may be coupled directly to neurostimulator 20, the lead connector is typically coupled to lead extension 22 as is shown in FIG. 1. An example of a lead extension is Model 7495 available from Medtronic, Inc.
  • a physician's programmer utilizes telemetry to communicate with the implanted neurostimulator 20 to enable the physician to program and manage a patient's therapy and troubleshoot the system.
  • a typical physician's programmer is available from Medtronic, Inc. and bears Model No. 7432.
  • a patient's programmer also uses telemetry to communicate with neurostimulator 20 so as to enable the patient to manage some aspects of their own therapy as defined by the physician.
  • An example of a patient programmer is Model 7434 Itrel® 3 EZ Patient Programmer available, from Medtronic, Inc.
  • Implantation of a neurostimulator typically begins with the implantation of at least one stimulation lead while the patient is under a local anesthetic. While there are many spinal cord lead designs utilized with a number of different implantation techniques, the largest distinction between leads revolves around how they are implanted. For example, surgical leads have been shown to be highly effective, but require a laminectomy for implantation. Percutaneous leads can be introduced through a needle, a much easier procedure. To simplify the following explanation, discussion will focus on percutaneous lead designs, although it will be understood by those skilled in the art that the inventive aspects are equally applicable to surgical leads.
  • the lead's distal end is typically anchored to minimize movement of the lead after implantation.
  • the lead's proximal end is typically configured to connect to a lead extension 22. The proximal end of the lead extension is then connected to the neurostimulator 20.
  • FIG. 2 illustrates a DBS system implanted in a patient 40 and comprises substantially the same components as does an SCS; that is, at least one neurostimulator, at least one extension, and at least one stimulation lead containing one or more electrodes.
  • each neurostimulator 42 is implanted in the pectoral region of patient 40.
  • Extensions 44 are deployed up through the patient's neck, and leads 46 are implanted in the patient's brain as is shown at 48.
  • each of leads 46 is connected to its respective extension 44 just above the ear on both sides of patient 40.
  • FIG. 3 is an isometric view of the distal end of lead 46.
  • four ring electrodes 48 are positioned on the distal end of lead 46 and coupled to internal conductors or filers (not shown) contained within lead 46.
  • internal conductors or filers not shown
  • FIG.4 is an isometric view of the distal end of extension 44, which includes a connector portion 45 having four internal contacts 47.
  • the proximal end of the DBS lead plugs into distal connector 45 of extension 44 and is held in place by means of, for example, a plurality (e.g. four) of set screws 50.
  • lead 46 terminates in a series of proximal electrical ring contacts 48 (only one of which is shown in FIG. 5). Lead 46 may be inserted through an axially aligned series of openings 52 (again only one shown) in screw block 54.
  • FIG. 6 is a top view of lead 46 shown in FIG. 2.
  • FIGS. 7 and 8 are cross-sectional views taken along lines 7-7 and 8-8, respectively, in FIG. 6.
  • Distal end 60 of lead 46 includes at least one electrode 62 (four are shown). As stated previously, up to eight electrodes may be utilized. Each of electrodes 62 is preferably constructed as is shown in FIG. 8.
  • electrode 62 may comprise a conductive ring 71 on the outer surface of the elongate tubing making up distal shaft 60.
  • Each electrode 62 is electrically coupled to a longitudinal wire 66 (shown in FIGS. 7 and 8) which extends to a contact 64 at the proximal end of lead 46.
  • Longitudinal wires 66 may be of a variety of configurations; e.g. discreet wires, printed circuit conductors, etc. From the arrangement shown in FIG. 6, it should be clear that four conductors or filers run through the body of lead 46 to electrically connect the proximal electrodes 64 to the distal electrodes 62.
  • the longitudinal conductors 66 may be spirally configured along the axis of lead 46 until they reach the connector contacts.
  • the shaft of lead 46 preferably has a lumen 68 extending therethrough for receiving a stylet that adds a measure of rigidity during installation of the lead.
  • the shaft preferably comprises a comparatively stiffer inner tubing member 70 (e.g. a polyamine, polyamide, high density polyethylene, polypropylene, polycarbonate or the like). Polyamide polymers are preferred.
  • the shaft preferably includes a comparatively softer outer tubing member or jacket 72; e.g. silicon or other suitable elastomeric polymer.
  • the conductive rings 71 are preferably of a biocompatible metal such as one selected from the noble group of metals, preferably palladium, platinum or gold and their alloys.
  • FIG. 9 illustrates an alternative lead 74 wherein distal end 76 is broader (e.g. paddle-shaped) to support a plurality of distal electrodes 78.
  • a lead of this type is shown in FIG. 1.
  • distal electrodes 78 are coupled to contacts 64 each respectively by means of an internal conductor or filer.
  • a more detailed description of the leads shown in the FIGS. 6 and 9 may be found in U.S. Patent No. 6,529,774 issued March 4, 2003 and entitled "Extradural Leads, Neurostimulator Assemblies, and Processes of Using Them for Somatosensory and Brain Stimulation".
  • FIGs. 10 and 11 are longitudinal and radial cross-sectional views, respectively, of a helically wound lead of the type shown in FIG. 6.
  • the lead comprises an outer lead body or jacket 80; a plurality of helically wound, co-radial lead filers 82; and a stylet lumen 84.
  • a stylet is a stiff, formable insert placed in the lead during implant so as to enable the physician to steer the lead to an appropriate location.
  • FIG. 10 illustrates four separate, co-radially wound filers 86, 88, 90 and 92 which are electrically insulated from each other and electrically couple a single electrode 62 (FIG. 6) to a single contact 64 (FIG. 6).
  • the lead filers 82 have a specific pitch and form a helix of a specific diameter.
  • the helix diameter is relevant in determining the inductance of the lead.
  • These filers themselves also have a specific diameter and are made of a specific material.
  • the filer diameter, material, pitch and helix diameter are relevant in determining the impedance of the lead.
  • the inductance contributes to a frequency dependent impedance.
  • FIGs. 12 and 13 are longitudinal and radially cross- sectional views, respectively, of a cabled lead.
  • the lead comprises outer lead body or jacket 94, stylet lumen 96, and a plurality (e.g. four, eight, etc.) of straight lead filers 98.
  • FIG. 14 is an exploded view of a neurostimulation system that includes an extension 100 configured to be coupled between a neurostimulator 102 and lead 104.
  • the proximal portion of extension 100 comprises a connector 106 configured to be received or plugged into connector block 109 of neurostimulator 102.
  • the distal end of extension 100 likewise comprises a connector 110 including internal contacts 111 configured to receive the proximal end of lead 104 having contacts 112 thereon.
  • the distal end of lead 104 includes distal electrodes 114.
  • FIG. 15 is a cross-sectional view of extension 100.
  • Lead extension 100 has a typical diameter of 0.1 inch, which is significantly larger than that of lead 104 so as to make extension 100 more durable than lead 104.
  • Extension 100 differs from lead 104 also in that each filer 106 in lead body 100 is helically wound or coiled in its own lumen 108 and not co-radially wound with the rest of the filers as was the case in lead 104.
  • the diameter of typical percutaneous leads is approximately 0.05 inch. This diameter is based upon the diameter of the needle utilized in the surgical procedure to deploy the lead and upon other clinical anatomical requirements.
  • the length of such percutaneous SCS leads is based upon other clinical anatomical requirements.
  • the length of such percutaneous SCS leads is typically 28 centimeters; however, other lengths are utilized to meet particular needs of specific patients and to accommodate special implant locations.
  • Lead length is an important factor in determining the suitability of using the lead in an MRI environment. For example, the greater length of the lead, the larger the effective loop area that is impacted by the electromagnetic field (i.e. the longer the lead, the larger the antenna). Furthermore, depending on the lead length, there can be standing wave effects that create areas of high current along the lead body. This can be problematic if the areas of high current are near the distal electrodes.
  • the cable lead has a smaller DC resistance because the length of the straight filer is less than that of a coiled filer and the impedance at high frequency is reduced because the inductance has been significantly reduced. It has been determined that the newer cabled filer designs tend to be more problematic in an MRI environment than do the wound helix filer designs. It should be noted that straight filers for cable leads sometimes comprise braided stranded wire that includes a number of smaller strands woven to make up each filer. This being the case, the number of strands could be varied to alter the impedance.
  • the resistance R of a lead filer is governed by the equation:
  • R — Equation (1) ⁇ a
  • R the resistance
  • L the length of the filer
  • ⁇ the conductivity
  • a the cross- sectional area. Decreasing the conductivity and/or the cross-sectional area of the filer will increase resistance proportionally.
  • One typical lead utilizes a chromium-cobalt (non-cored MP35N) filer having a conductivity of l.lxlO 6 mhos/meter, a diameter of approximately 0.005 inch, and a length of approximately 100 centimeters.
  • the resistance R of the lead is approximately twenty ohms. If the diameter were reduced to 0.002 inch, R could be increased to approximately 710 ohms (or approximately 126 ohms for a 28 centimeter lead).
  • the lead body or lead jacket is configured to shunt induced RF energy from the filers to the patient's body along the length of the lead (or at least a portion thereof). That is, the lead body or lead jacket itself acts as a distributed shunt from the conductive lead filers to the patient's body during an MRI scan. This may be accomplished by (1) providing a shunt conductance (i.e. a DC path) between a filer and a patient's body creating a current path regardless of frequency; (2) a shunt capacitance (i.e. an AC current path) that allows current to flow at high frequency (i.e.
  • a shunt conductance i.e. a DC path
  • a shunt capacitance i.e. an AC current path
  • FIGs. 16-19 are schematic diagrams illustrating how the lossy jacket may be configured. If a filer is represented by conductor 81 and a patient's body is represented by a grounded conductor 83, FIG. 16 illustrates a capacitive shunt 85 in parallel with a conductive shunt 87. In FIG. 17, the shunt is comprised of the series combination of resistor 89 and capacitor 91. In FIG. 18, the shunt comprises the parallel combination of capacitor 93 and resistor 95 in series with resistor 97, and in FIG.
  • FIG. 20 is a longitudinal view of a first exemplary embodiment of the inventive medical lead illustrating a partially exploded portion of lead jacket 120.
  • FIG. 21 is a cross- sectional view of the lead shown in FIG. 20 taken along line 21-21.
  • the lead shown in FIGs. 20 and 21 is substantially similar to that shown in FIGs. 12 and 13 respectively and therefore like reference numerals denote like elements.
  • Straight filers 98 shown in FIG. 21 are each provided with protective insulation 121 (e.g. Teflon), and jacket 120 may be made from materials such as silicone, polyether urethane, etc.
  • protective insulation 121 e.g. Teflon
  • the jacket material may be doped with a dielectric material such as carbon, talc, and minerals such as calcium carbonate, titanium dioxide, aluminum dioxide, sapphire, mica, and silica. Both pyrolitic and vitreous carbon would be suitable.
  • the dopant should be biocompatible and preferably have a dielectric constant greater than five. Both the type and concentration of dopant is selected to obtain the desired frequency response in accordance with known techniques.
  • the dopant is represented graphically in FIGs. 20 and 21 as particles 122. These particles form tiny capacitors with each other and with the conductive filers so as to conduct induced RF energy at high frequencies from filers 98 to body tissue or fluids.
  • the doping concentration may be uniform or non-uniform along the length of the lead. For example, only certain portions of the lead might be doped; e.g. the distal end of the lead close to the stimulation electrode so as to create a different characteristic impedance than the rest of the lead. Alternatively, the dopant concentration may vary along the length of the lead. This change in characteristic impedance could create a reflection at high frequencies so as to keep induced RF energy away from the stimulation electrode.
  • the lead body or jacket may be provided with a plurality of pores 124 shown in FIGs. 22 and 23, which are longitudinal and cross-sectional views, respectively.
  • Pores 124 (produced by means of, for example, laser drilling) permit body fluid to enter the lead and create a larger capacitance between the patient's body and lead filers 98. This larger capacitance at higher frequency would enhance the conduction of induced RF energy from filers 98 to the patient's body.
  • pores 124 may be placed anywhere along the length of the lead (e.g. close to the stimulation electrodes) or the pore density may be varied along the length of the lead. If desired, the jacket may be doped in addition to being provided with pores 124.
  • the dopant and/or pores may be concentrated in a longitudinal path limited to one or more selected circumferential sectors as is shown in FIGs. 24 and 25, respectively, or the concentration of dopant may be varied circumferentially.
  • concentrations of dopant and pores can vary both ' longitudinally and circumferentially.
  • one or more conductive strips 125 may be disposed longitudinally along the length of the lead (or a portion thereof) as is shown in FIG. 26.
  • the jacket material may be varied along the length of the lead to provide different lossy conduction at different locations.
  • sheath 120 may be comprised of alternating sections 127 and 129 of dielectric (e.g. urethane) and conductive sections (e.g. titanium, platinum, stainless steel, conductive/ polymers, chromium-cobalt alloys, etc.), respectively.
  • Yet another embodiment of the present invention comprises a multi-layered jacket of the type shown in FIG. 28 including, for example, alternating layers 131 and 133 of dielectric and conductive material, respectively; e.g. alternating layers of Teflon TM impregnated to be conductive or non-conductive.
  • the alternating layers may be produced by, for example, co-extrusion, dispersion, coating, vapor deposition or atomized coating in accordance with known techniques; or alternatively, the lead jacket could be wrapped with alternating conductive and non-conductive layers to create a shunt capacitance. This could be done using two conductive layers (e.g. doped Teflon TM or PTFE) and one dielectric layer (e.g.
  • FIGs. 29 and 30 PTFE doped with a dielectric material as is shown in FIGs. 29 and 30.
  • Layers could be, for example, extruded or wrapped. Preferably, the two conductive layers are wrapped and the intermediate non-conductive layer is extruded. In FIG. 29, the layers 135 are wrapped in an edge-abutting manner, whereas in FIG. 30, the layers are wrapped in an overlapping manner as indicated by dotted line 137.
  • FIG. 39 illustrates a medical lead comprised of a plurality of filers jacketed as described above and bundled as, for example, by adhering or otherwise securing the jacketed filers.
  • FIGs. 31-36 illustrate yet another exemplary embodiment of the inventive lead incorporating a helical coil of wire that forms a continuous first plate of a capacitor, the second plate being each of the conductive filers 98.
  • This increases the capacitance to the patient's body to shunt induced RF energy to the patient's body at MRI frequencies.
  • Helical coil 126 may take the form of a flat ribbon and may be imbedded in lead jacket 120 as is shown in FIGs. 31 and 32 which are isometric and cross-sectional views respectively. It is known that
  • C is the capacitance
  • A is the area of the capacitor plates
  • d is the distance between the plates
  • ⁇ is the dielectric constant of the material between them. It can be seen that the capacitance increases with area. Thus, the use of a flat ribbon coil will increase the capacitance. It should also be apparent that the smaller the distance between coil 126 and filers 98, the greater the capacitance between them. Thus, the lead may be constructed so as to place filers 98 closer to jacket 120. Additionally, the capacitance will increase if the jacket is made of a material having a higher dielectric constant.
  • jacket 120 may be provided with a plurality of pores 124 to expose coil 126 to body tissue.
  • coil 126 may be placed on the inner surface of jacket 120 as is shown in FIG. 34 in order to reduce the distance between coil 126 and filers 98.
  • Jacket 120 may be doped with a conductive material or provided with pores in order to increase the capacitance as described above.
  • coil 126 may be positioned on or imbedded within an outer surface of jacket 120 as is shown in FIGs. 35 and 36 which are isometric and cross-sectional views, respectively.
  • FIG. 37 is a cross-sectional view of yet another exemplary embodiment of the present invention.
  • the region between the insulated filers and the interior surface of jacket 120 is filled with a material 130 (preferably having a dielectric constant greater than three) that creates a capacitance with conductive filers 98.
  • a material 130 preferably having a dielectric constant greater than three
  • the conductive gel could fill only selected portions along the length of the lead.
  • the entire lead jacket 120 may be made of a flexible biocompatible conductive material.
  • FIG. 38 illustrates yet another embodiment of the present invention.
  • the entire lead jacket could be removed (i.e. the lead is manufactured without a lead jacket) or no lead jacket is placed around selected portions of the lead as is shown at 132.
  • the individual filers are separated from each other and from the patient's body tissue or fluids by the insulation 121 on each of the conductive filers. Certain areas of the lead that are most prone to damage could be provided with a lead jacket while other portions of the lead are jacket-free.
  • a lead may be provided with a jacket that could be retracted or removed after the lead has been implanted. This provides for good handling and steerability while maximizing its lossy characteristics along the length of the lead.

Abstract

L'invention concerne une dérivation de stimulation (104) configuré pour s'implanter dans le corps d'un patient (28), qui comprend au moins une électrode de stimulation distale (114) et au moins une limeuse conductrice (98) couplée électriquement à l'électrode de stimulation distale (114). Une gaine (120) enveloppe la limeuse conductrice (98) et crée un chemin ménagé le long d'au moins une partie de la longueur de la dérivation (104) pour conduire l'énergie RF induite de la limeuse conductrice (98) au corps du patient (28).
PCT/US2004/042081 2004-03-30 2004-12-14 Derivation implantable sure pour l'irm WO2005102447A1 (fr)

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US60/557,991 2004-03-30
US10/993,195 US7844344B2 (en) 2004-03-30 2004-11-18 MRI-safe implantable lead
US10/993,195 2004-11-18

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WO2010038178A1 (fr) * 2008-10-02 2010-04-08 Koninklijke Philips Electronics N.V. Electrode pour dispositif médical implantable
US7844344B2 (en) 2004-03-30 2010-11-30 Medtronic, Inc. MRI-safe implantable lead
US7844343B2 (en) 2004-03-30 2010-11-30 Medtronic, Inc. MRI-safe implantable medical device
US7853332B2 (en) 2005-04-29 2010-12-14 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US7877150B2 (en) 2004-03-30 2011-01-25 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US8027736B2 (en) 2005-04-29 2011-09-27 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US8244375B2 (en) 2008-08-25 2012-08-14 Pacesetter, Inc. MRI compatible lead
US8280526B2 (en) 2005-02-01 2012-10-02 Medtronic, Inc. Extensible implantable medical lead
US8335570B2 (en) 2008-10-09 2012-12-18 Boston Scientific Neuromodulation Corporation Electrical stimulation leads having RF compatibility and methods of use and manufacture
US8483842B2 (en) 2007-04-25 2013-07-09 Medtronic, Inc. Lead or lead extension having a conductive body and conductive body contact
US8897887B2 (en) 2006-06-08 2014-11-25 Greatbatch Ltd. Band stop filter employing a capacitor and an inductor tank circuit to enhance MRI compatibility of active medical devices
US8989840B2 (en) 2004-03-30 2015-03-24 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9044593B2 (en) 2007-02-14 2015-06-02 Medtronic, Inc. Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
US9108066B2 (en) 2008-03-20 2015-08-18 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US9155877B2 (en) 2004-03-30 2015-10-13 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9186499B2 (en) 2009-04-30 2015-11-17 Medtronic, Inc. Grounding of a shield within an implantable medical lead
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US9463317B2 (en) 2012-04-19 2016-10-11 Medtronic, Inc. Paired medical lead bodies with braided conductive shields having different physical parameter values
US9731119B2 (en) 2008-03-12 2017-08-15 Medtronic, Inc. System and method for implantable medical device lead shielding
USRE46699E1 (en) 2013-01-16 2018-02-06 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US9931514B2 (en) 2013-06-30 2018-04-03 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US9993638B2 (en) 2013-12-14 2018-06-12 Medtronic, Inc. Devices, systems and methods to reduce coupling of a shield and a conductor within an implantable medical lead
US10080889B2 (en) 2009-03-19 2018-09-25 Greatbatch Ltd. Low inductance and low resistance hermetically sealed filtered feedthrough for an AIMD
US10155111B2 (en) 2014-07-24 2018-12-18 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10279171B2 (en) 2014-07-23 2019-05-07 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10350421B2 (en) 2013-06-30 2019-07-16 Greatbatch Ltd. Metallurgically bonded gold pocket pad for grounding an EMI filter to a hermetic terminal for an active implantable medical device
US10537730B2 (en) 2007-02-14 2020-01-21 Medtronic, Inc. Continuous conductive materials for electromagnetic shielding
US10559409B2 (en) 2017-01-06 2020-02-11 Greatbatch Ltd. Process for manufacturing a leadless feedthrough for an active implantable medical device
US10561837B2 (en) 2011-03-01 2020-02-18 Greatbatch Ltd. Low equivalent series resistance RF filter for an active implantable medical device utilizing a ceramic reinforced metal composite filled via
US10589107B2 (en) 2016-11-08 2020-03-17 Greatbatch Ltd. Circuit board mounted filtered feedthrough assembly having a composite conductive lead for an AIMD
US10905888B2 (en) 2018-03-22 2021-02-02 Greatbatch Ltd. Electrical connection for an AIMD EMI filter utilizing an anisotropic conductive layer
US10912945B2 (en) 2018-03-22 2021-02-09 Greatbatch Ltd. Hermetic terminal for an active implantable medical device having a feedthrough capacitor partially overhanging a ferrule for high effective capacitance area
US11198014B2 (en) 2011-03-01 2021-12-14 Greatbatch Ltd. Hermetically sealed filtered feedthrough assembly having a capacitor with an oxide resistant electrical connection to an active implantable medical device housing

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US9295828B2 (en) 2001-04-13 2016-03-29 Greatbatch Ltd. Self-resonant inductor wound portion of an implantable lead for enhanced MRI compatibility of active implantable medical devices
US9248283B2 (en) 2001-04-13 2016-02-02 Greatbatch Ltd. Band stop filter comprising an inductive component disposed in a lead wire in series with an electrode
US8989840B2 (en) 2004-03-30 2015-03-24 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
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US7877150B2 (en) 2004-03-30 2011-01-25 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US9155877B2 (en) 2004-03-30 2015-10-13 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
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US8280526B2 (en) 2005-02-01 2012-10-02 Medtronic, Inc. Extensible implantable medical lead
US7853332B2 (en) 2005-04-29 2010-12-14 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US8027736B2 (en) 2005-04-29 2011-09-27 Medtronic, Inc. Lead electrode for use in an MRI-safe implantable medical device
US8897887B2 (en) 2006-06-08 2014-11-25 Greatbatch Ltd. Band stop filter employing a capacitor and an inductor tank circuit to enhance MRI compatibility of active medical devices
US10398893B2 (en) 2007-02-14 2019-09-03 Medtronic, Inc. Discontinuous conductive filler polymer-matrix composites for electromagnetic shielding
US10537730B2 (en) 2007-02-14 2020-01-21 Medtronic, Inc. Continuous conductive materials for electromagnetic shielding
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US9731119B2 (en) 2008-03-12 2017-08-15 Medtronic, Inc. System and method for implantable medical device lead shielding
US9108066B2 (en) 2008-03-20 2015-08-18 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US8244375B2 (en) 2008-08-25 2012-08-14 Pacesetter, Inc. MRI compatible lead
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WO2010027711A2 (fr) * 2008-09-02 2010-03-11 Boston Scientfic Neuromodulation Corporation Systèmes, dispositifs et procédés pour le couplage électrique de bornes à des électrodes de systèmes de stimulation électriques
WO2010027711A3 (fr) * 2008-09-02 2010-05-06 Boston Scientfic Neuromodulation Corporation Systèmes, dispositifs et procédés pour le couplage électrique de bornes à des électrodes de systèmes de stimulation électriques
WO2010038178A1 (fr) * 2008-10-02 2010-04-08 Koninklijke Philips Electronics N.V. Electrode pour dispositif médical implantable
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US10080889B2 (en) 2009-03-19 2018-09-25 Greatbatch Ltd. Low inductance and low resistance hermetically sealed filtered feedthrough for an AIMD
US10035014B2 (en) 2009-04-30 2018-07-31 Medtronic, Inc. Steering an implantable medical lead via a rotational coupling to a stylet
US9216286B2 (en) 2009-04-30 2015-12-22 Medtronic, Inc. Shielded implantable medical lead with guarded termination
US9186499B2 (en) 2009-04-30 2015-11-17 Medtronic, Inc. Grounding of a shield within an implantable medical lead
US9629998B2 (en) 2009-04-30 2017-04-25 Medtronics, Inc. Establishing continuity between a shield within an implantable medical lead and a shield within an implantable lead extension
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US10561837B2 (en) 2011-03-01 2020-02-18 Greatbatch Ltd. Low equivalent series resistance RF filter for an active implantable medical device utilizing a ceramic reinforced metal composite filled via
US11071858B2 (en) 2011-03-01 2021-07-27 Greatbatch Ltd. Hermetically sealed filtered feedthrough having platinum sealed directly to the insulator in a via hole
US11198014B2 (en) 2011-03-01 2021-12-14 Greatbatch Ltd. Hermetically sealed filtered feedthrough assembly having a capacitor with an oxide resistant electrical connection to an active implantable medical device housing
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USRE46699E1 (en) 2013-01-16 2018-02-06 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US9427596B2 (en) 2013-01-16 2016-08-30 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US10350421B2 (en) 2013-06-30 2019-07-16 Greatbatch Ltd. Metallurgically bonded gold pocket pad for grounding an EMI filter to a hermetic terminal for an active implantable medical device
US9931514B2 (en) 2013-06-30 2018-04-03 Greatbatch Ltd. Low impedance oxide resistant grounded capacitor for an AIMD
US9993638B2 (en) 2013-12-14 2018-06-12 Medtronic, Inc. Devices, systems and methods to reduce coupling of a shield and a conductor within an implantable medical lead
US10279171B2 (en) 2014-07-23 2019-05-07 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10155111B2 (en) 2014-07-24 2018-12-18 Medtronic, Inc. Methods of shielding implantable medical leads and implantable medical lead extensions
US10589107B2 (en) 2016-11-08 2020-03-17 Greatbatch Ltd. Circuit board mounted filtered feedthrough assembly having a composite conductive lead for an AIMD
US10559409B2 (en) 2017-01-06 2020-02-11 Greatbatch Ltd. Process for manufacturing a leadless feedthrough for an active implantable medical device
US10905888B2 (en) 2018-03-22 2021-02-02 Greatbatch Ltd. Electrical connection for an AIMD EMI filter utilizing an anisotropic conductive layer
US10912945B2 (en) 2018-03-22 2021-02-09 Greatbatch Ltd. Hermetic terminal for an active implantable medical device having a feedthrough capacitor partially overhanging a ferrule for high effective capacitance area
US11712571B2 (en) 2018-03-22 2023-08-01 Greatbatch Ltd. Electrical connection for a hermetic terminal for an active implantable medical device utilizing a ferrule pocket

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