HEADER FOR A NEUROSTIMULATOR

An implantable pulse generator (IPG) including a case containing an energy storage device and one or more electrode leads. A header is coupled to the case. The header includes a cassette, an antenna coupled to the cassette and electrically coupled to the case, the case configured as a part of the antenna for receiving and transmitting electromagnetic signals, and an electrode attachment structure configured to couple with the cassette and configured to couple with the one or more electrode leads.

BACKGROUND

There is a demand for improvement in antenna systems in implantable neurostimulation devices such as an implantable pulse generator (IPG). Current stimulation systems rely on wireless communication to maintain control of the implantable neurostimulation system. This wireless communication is frequently performed using one or more antennas. Construction of such implantable devices has many difficulties because of the biological environment that they must survive in and because of the compact size requirements. Therefore, needs exist for construction techniques for such devices, which fulfill requirements while maintaining ease of construction and manufacturing.

SUMMARY

One embodiment disclosed herein relates to an implantable pulse generator (IPG). The IPG includes a case containing an energy storage device. A header is coupled to the case. The header includes a cassette, an antenna coupled to the cassette and electrically coupled to the case, the case configured as a part of the antenna for receiving and transmitting electromagnetic signals, and an electrode attachment structure configured to couple with the cassette and configured to couple with one or more electrode leads.

Another disclosed embodiment relates to a header for an implantable biomedical device. The header includes a cassette providing a support structure, an antenna coupled to the cassette and configured to be electrically coupled to a case of the implantable biomedical device, the case configured as a part of the antenna for receiving and transmitting electromagnetic signals. The header also including an electrode attachment structure configured to couple with the cassette and configured to couple with one or more electrode leads.

Yet another disclosed embodiment relates to an implantable pulse generator (IPG). The IPG includes a case containing an energy storage device. The IPG also includes a header coupled to the case. The header include a cassette providing a support structure, an antenna bent at least partially around the cassette and electrically coupled to the case through at least one capacitor, the case configured as a part of the antenna for receiving and transmitting electromagnetic signals, an electrode attachment structure configured to couple with the cassette and configured to couple with one or more electrode leads and an epoxy fill material for sealing the header.

In addition to the foregoing, other aspects are described in the claims, drawings, and text forming a part of the disclosure set forth herein. The foregoing is a summary and thus may contain simplifications, generalizations, inclusions, and/or omissions of detail. Consequently, those skilled in the art will appreciate that the summary is descriptive only and further reference may be made to the drawings and description below for clarification. Other aspects, features, and advantages of the devices and/or processes and/or other subject matter described herein will become apparent upon review of the disclosure set forth herein.

The use of the same symbols in different drawings typically indicates similar or identical items unless context dictates otherwise.

DETAILED DESCRIPTION

The present application relates to an antenna and header for an IPG, also referred to herein as an “implantable neurostimulator” or a “neurostimulator.” The IPG may be a sacral nerve stimulation treatment system configured to treat overactive bladder (“OAB”) and relieve symptoms of bladder related dysfunction. However, the devices and systems disclosed herein may also be utilized for a variety of neuromodulation uses, such as fecal dysfunction, and the treatment of pain or other indications, such as movement or affective disorders. The devices and systems disclosed herein may further be used for other implantable devices such as but not limited to pacemakers, deep brain stimulation devices, etc.

FIG.1schematically illustrates an exemplary nerve stimulation system, which includes both a trial neurostimulation system200and a permanently implanted neurostimulation system100. An External Pulse Generator (EPG)80and an Implantable Pulse Generator (IPG)10are each compatible with and wirelessly communicate with a clinician programmer60and a patient remote70, which are used in positioning and/or programming the trial neurostimulation system200and/or permanently implanted system100after a successful trial. Each of IPG10and EPG80are configured to be connected to leads20with nerve stimulation electrodes40coupled thereto. The clinician programmer can include specialized software, specialized hardware, and/or both, to aid in lead placement, programming, re-programming, stimulation control, and/or parameter setting. In addition, each of the IPG10and the EPG80allows the patient at least some control over stimulation (e.g., initiating a pre-set program, increasing or decreasing stimulation), and/or to monitor battery status with the patient remote. This approach also allows for an almost seamless transition between the trial system and the permanent system.

The clinician programmer60is used by a physician to adjust the settings of the EPG80and/or IPG10while the lead20is implanted within the patient. The clinician programmer can be a tablet computer or any other computing device used by the clinician to program the IPG10, or to control the EPG80during the trial period. The clinician programmer60can also include capability to record stimulation-induced electromyograms to facilitate lead placement and programming. The patient remote70can allow the patient to turn the stimulation on or off, or to vary stimulation from the IPG10while implanted, or from the EPG80during the trial phase.

The clinician programmer60has a control unit which can include a microprocessor and specialized computer code instructions for implementing methods and systems for use by a physician in deploying the treatment system and setting up treatment parameters. The clinician programmer60generally includes a user interface which can be a graphical user interface. Other connectors of the clinician programmer60may be configured for coupling with an electrical ground or ground patch, an electrical pulse generator (e.g., an EPG80or an IPG10), or the like.

The clinician programmer is configured to operate in combination with an EPG80when placing leads in a patient body. The clinician programmer60can be electronically coupled to the EPG80during test simulation through a specialized cable set. The test simulation cable set can connect the clinician programmer device60to the EPG80and allow the clinician programmer60to configure, modify, or otherwise program the electrodes40on the leads20connected to the EPG80.

The electrical pulses generated by the EPG80and IPG10are delivered to one or more targeted nerves via one or more neurostimulation electrodes40at or near a distal end of each of one or more leads20. The leads20can have a variety of shapes, can be a variety of sizes, and can be made from a variety of materials, which size, shape, and materials can be tailored to the specific treatment application. While in this embodiment, the lead is of a suitable size and length to extend from the IPG10and through one of the foramen of the sacrum to a targeted sacral nerve, in various other applications, the leads may be, for example, implanted in a peripheral portion of the patient's body, such as in the arms or legs, and can be configured to deliver electrical pulses to the peripheral nerve such as may be used to relieve chronic pain. The leads and/or the stimulation programs may vary according to the nerves being targeted.

For reference,FIGS.2A-2Cdepict diagrams of various nerve structures of a patient, which may be used in neurostimulation treatments.FIG.2Adepicts the different sections of the spinal cord and the corresponding nerves within each section. The spinal cord is a long, thin bundle of nerves and support cells that extend from the brainstem along the cervical cord, through the thoracic cord and to the space between the first and second lumbar vertebra in the lumbar cord. Upon exiting the spinal cord, the nerve fibers split into multiple branches that innervate various muscles and organs transmitting impulses of sensation and control between the brain and the organs and muscles. Since certain nerves may include branches that innervate certain organs, such as the bladder, and branches that innervate certain muscles of the leg and foot, stimulation of the nerve at or near the nerve root near the spinal cord can stimulate the nerve branch that innervate the targeted organ, which may also result in muscle responses associated with the stimulation of the other nerve branch.

FIG.2Bdepicts the nerves associated with the lower back section, in the lower lumbar cord region where the nerve bundles exit the spinal cord and travel through the sacral foramens of the sacrum. In some illustrative embodiments, the neurostimulation lead20is advanced through the foramen until the neurostimulation electrodes are positioned at the anterior sacral nerve root, while the anchoring portion of the lead proximal of the stimulation electrodes are generally disposed dorsal of the sacral foramen through which the lead passes, so as to anchor the lead in position.FIG.2Cdepicts a detailed view of the nerves of the lumbosacral trunk and the sacral plexus, in particular, the S1-S5 nerves of the lower sacrum. The S3 sacral nerve is of particular interest for treatment of bladder related dysfunction, and in particular OAB.

FIG.3schematically illustrates an example of a fully implanted neurostimulation system100adapted for sacral nerve stimulation. Neurostimulation system100includes an IPG10implanted in a lower back region and connected to a neurostimulation lead20extending through the S3 foramen for stimulation of the S3 sacral nerve. The lead is anchored by a tined anchor portion30that maintains a position of a set of neurostimulation electrodes40along the targeted nerve, which in this example, is the anterior sacral nerve root S3 which enervates the bladder so as to provide therapy for various bladder related dysfunctions. While this embodiment is adapted for sacral nerve stimulation, similar systems can be used in treating patients with, for example, chronic, severe, refractory neuropathic pain originating from peripheral nerves or various urinary dysfunctions or still further other indications. Implantable neurostimulation systems can be used to either stimulate a target peripheral nerve or the posterior epidural space of the spine.

Properties of the electrical pulses can be controlled via a controller of the implanted pulse generator10. In some embodiments, these properties can include, for example, the frequency, strength, pattern, duration, or other aspects of the electrical pulses. These properties can include, for example, a voltage, a current, or the like. This control of the electrical pulses can include the creation of one or more electrical pulse programs, plans, or patterns, and in some embodiments, this can include the selection of one or more pre-existing electrical pulse programs, plans, or patterns. In the embodiment depicted inFIG.3, the implantable neurostimulation system100includes a controller in the IPG10having one or more pulse programs, plans, or patterns that may be pre-programmed or created as discussed above. In some embodiments, these same properties associated with the IPG10may be used in an EPG80of a partly implanted trial system used before implantation of the permanent neurostimulation system100.

FIG.4illustrates an example neurostimulation system100that is fully implantable and adapted for sacral nerve stimulation treatment. The implantable system100includes an IPG10that is coupled to a neurostimulation lead20that includes a group of neurostimulation electrodes40at a distal end of the lead. The lead includes a lead anchor portion30with a series of tines extending radially outward so as to anchor the lead and maintain a position of the neurostimulation lead20after implantation. The lead20may further include one or more radiopaque markers25to assist in locating and positioning the lead using visualization techniques such as fluoroscopy. In some embodiments, the IPG10provides monopolar or bipolar electrical pulses that are delivered to the targeted nerves through one or more neurostimulation electrodes, typically, but not limited to four electrodes. In sacral nerve stimulation, the lead is typically implanted through the S3 foramen as described herein.

The system100may further include a patient remote70and clinician programmer60, each configured to wirelessly communicate with the implanted IPG10. The clinician programmer60may be a tablet computer used by the clinician to program the IPG10. The patient remote70may be a battery-operated, portable device that utilizes radio-frequency (RF) signals to communicate with the IPG10and allows the patient to adjust the stimulation levels, check the status of the IPG10battery level, and/or to turn the stimulation on or off

FIGS.5A and5Bshow detail views of an IPG10and its internal components. In some illustrative embodiments, the pulse generator may generate one or more non-ablative electrical pulses that are delivered to a nerve to control pain or cause some other desired effect, for example to inhibit, prevent, or disrupt neural activity for the treatment of OAB or bladder related dysfunction. In some applications, the pulses having a pulse amplitude in a range between 0 mA to 1,000 mA, 0 mA to 100 mA, 0 mA to 50 mA, 0 mA to 25 mA, and/or any other or intermediate range of amplitudes may be used. One or more of the pulse generators may include a controller (e.g. processor) and/or memory adapted to provide instructions to and receive information from the other components of the implantable neurostimulation system. The processor may include a microprocessor, such as a commercially available microprocessor from Intel® or Advanced Micro Devices, Inc.®, or the like. The IPG10may include an energy source or energy storage device24, such as a battery and/or one or more capacitors, and may also include a wireless charging unit.

One or more properties of the electrical pulses may be controlled via a controller of the IPG10. In some illustrative embodiments, these properties may include, for example, the frequency, strength, pattern, duration, or other aspects of the timing and magnitude of the electrical pulses. These properties may further include, for example, a voltage, a current, or the like. This control of the electrical pulses may include the creation of one or more electrical pulse programs, plans, or patterns, and in some embodiments, this may include the selection of one or more pre-existing electrical pulse programs, plans, or patterns. The IPG10includes a controller, also referred to herein as a processor or microprocessor, having one or more pulse programs, plans, or patterns that may be created and/or pre-programmed. In some illustrative embodiments, the IPG10may be programmed to vary stimulation parameters including pulse amplitude in a range from 0 mA to 10 mA, pulse width in a range from 50 μs to 500 μs, pulse frequency in a range from 5 Hz to 250 Hz, stimulation modes (e.g., continuous or cycling), and electrode configuration (e.g., anode, cathode, or off), to achieve the optimal therapeutic outcome specific to the patient. In particular, this allows for an optimal setting to be determined for each patient even though each parameter may vary from person to person.

As shown inFIGS.5A and5B, the IPG10may include a header portion11. The header portion11houses a feedthrough assembly12, a connector stack13, and a communication antenna16to facilitate wireless communication with the clinician programmer60and the patient remote70. The IPG10, excluding the header11, is covered with a titanium case17, which encases the circuitry23including the printed circuit board, memory and controller components that facilitate the electrical pulse programs described above. The titanium case17further encompasses an energy storage device24, which may be a battery. Encapsulating material11amay be utilized in order to encase at least a portion of the components of the header portion11.

As shown inFIG.5B, the feedthrough assembly12includes multiple pins that pass through from the case into the header11. The pins are shown inFIG.10protruding upwards from the case. The pins couple to the connector stack13in which the proximal end of the lead is coupled. The multiple pins correspond to the four electrodes of the neurostimulation lead. In some embodiments, a Balseal® type connector stack is electrically connected to a plurality of feedthrough pins. The pins may comprise niobium. Alternatively, the pins may be platinum or a platinum/iridium alloy. The pins may be brazed to an alumina ceramic insulator plate along with a titanium alloy flange. The feedthrough assembly may be laser seam welded to a titanium-ceramic brazed case to form a complete hermetic housing for the electronics. Some or all of the pieces of the IPG10forming the hermetic housing may be biocompatible, and specifically, may have external surfaces made of biocompatible materials.

FIG.6depicts a block diagram schematic illustration of one embodiment of the architecture of the IPG10. In some embodiments, each of the components of the architecture of the IPG10may be implemented using the processor, memory, and/or other hardware component of the IPG10. In some embodiments, the components of the architecture of the IPG10may include software that interacts with the hardware of the IPG10to achieve a desired outcome, and the components of the architecture of the IPG10may be located within the housing.

The IPG10may include a data module602. The data module602may be configured to manage data relating to the identity and properties of the IPG10. In some embodiments, the data module602may include one or several database that may, for example, include information relating to the IPG10such as, for example, the identification of the IPG10, one or several properties of the IPG10, or the like. In accordance with various illustrative embodiments, the data identifying the IPG10may include, for example, a serial number of the IPG10and/or other identifier of the IPG10including, for example, a unique identifier of the IPG10. In some embodiments, the information associated with a property of the IPG10may include, for example, data identifying the function of the IPG10, data identifying the power consumption of the IPG10, data identifying the charge capacity of the IPG10and/or power storage capacity of the IPG10, data identifying potential and/or maximum rates of charging of the IPG10, and/or the like.

The IPG10may include a pulse control604. In accordance with various illustrative embodiments, the pulse control604may be configured to control the generation of one or several pulses by the IPG10. In some embodiments, for example, this may be performed based on information that identifies one or several pulse patterns, programs, or the like. This information may further specify, for example, the frequency of pulses generated by the IPG10, the duration of pulses generated by the IPG10, the strength and/or magnitude of pulses generated by the IPG10, or any other details relating to the creation of one or several pulses by the IPG10. In accordance with various illustrative embodiments, this information may specify aspects of a pulse pattern and/or pulse program, such as, for example, the duration of the pulse pattern and/or pulse program, and/or the like. In accordance with various illustrative embodiments, information relating to and/or for controlling the pulse generation of the IPG10may be stored within the memory.

In accordance with various illustrative embodiments, the pulse module604may include stimulation circuitry. The stimulation circuitry may be configured to generate and deliver one or several stimulation pulses, and specifically may be configured to generate a voltage driving a current forming one or several stimulation pulses. This circuitry may include one or several different components that may be controlled to generate the one or several stimulation pulses, to control the one or several stimulation pulses, and/or to deliver the one or several stimulation pulses.

The IPG10may include an energy source, such as an energy storage device608. The energy storage device608, which may include the energy storage features, may be any device configured to store energy and may include, for example, one or several batteries, capacitors, fuel cells, or the like. The IPG10may further include, for example, a communication module600. The communication module600may be configured to send data to and receive data from other components and/or devices of the exemplary nerve stimulation system including, for example, the clinician programmer60and/or the patient remote70. In accordance with various illustrative embodiments, the communication module600may connect to one or several antennas16and may include software configured to control the one or several antennas to send information to and receive information from one or several of the other components of the IPG10. While discussed herein in the context of the IPG10, in accordance with various illustrative embodiments, the communication module600as disclosed herein may be supplemented or alternatively located by, for example, the patient remote70and/or the clinician programmer60.

FIG.7depicts the antenna circuit within the header11of the IPG10. The header11of the implantable nerve stimulator10includes an inverted F-type antenna16. A multi-purpose housing (i.e. case17) may serve as an electrode during stimulation and as a part of the antenna16during communication. The case17is coupled to circuit ground via at least one capacitor (e.g.,102and104). The capacitors may be configured to function as an open circuit to stimulation pulses and a conductive path (or closed circuit) for communication signals. For example, the capacitor may either function as an open circuit by having a high impedance or as a conductive path (closed circuit) by having little to no impedance. The impedance may be varied by changing the frequency of the electrical signal through the capacitor. The capacitor102and the capacitor104provide the case17an RF ground path allowing the case to be a ground reference for the antenna.

The feedthrough connector plate928may include a first riser plate929and a second riser plate930. Each of the riser plates may include a set of capacitively coupled feed through pins. In addition, a separate pin may be provided on the connector plate for connecting to the case. Each of the capacitively coupled feedthrough pins may include a ceramic layer between a metal portion (i.e., core) of the pin and the surrounding metal portions of a feedthrough plate or case (i.e., metal plate of the header). As shown inFIG.7, certain pins may be connected to the same conductive circuit and the case17. For example, pins P2, P3, P4and P7may be connected to pin P6via the feedthrough connector plate928and, thus, are connected to the case17of the IPG10and two of the capacitors102,104. While each riser plate depicted in the exemplary embodiment shown inFIG.7includes a set of five capacitively coupled feed through pins, any number of pins may be used depending upon the use and needs of the IPG10. In addition, the communication module, pulse control module and case may be connected to one or more of the feed through pins.

The capacitively coupled pins may also provide Magnetic Resonance Imaging (MRI) protection. For example, the presence of a magnetic field may be detected using the signal carried by the pins and the operation of the IPG10may be adjusted accordingly during an MRI procedure. For example, the IPG10may be temporarily shut down during the MRI procedure. As shown inFIG.7, the capacitors101,103and the inductor105may be configured as antenna impedance matching components. The electromagnetic field created during the MRI procedure impacts the inductive coil105and may be detected by the communication module.

Pulse control module604is configured to be connected to certain of the capacitively coupled feed through pins. For example, as shown inFIG.7, four of the pins (P8-P11) may each be connected to one of the output lines (604a-604d) of the pulse control module604. The communication module600is configured to be connected to one of the capacitively coupled feed through pins (e.g., P5). The communication module may include a transceiver configured to send and/or receive data to and/or from the antenna in order to communicate with outside devices such as the clinician programmer60and/or the patient remote70.

FIG.8depicts an isometric view of another embodiment of an IPG10. The header11is encapsulated with a material, typically transparent epoxy, but the encapsulating material is omitted from the view depicted inFIG.8.

FIG.9depicts an illustrative embodiment of the header11and an exploded view of its components for the illustrative embodiment shown inFIGS.5A and5B. The header11may include an antenna16, strain relief915, set screw block917, cassette923, X-ray identification925, lead frame927, and the encapsulating material11awhich surrounds the entire header11components. The header also includes the connector stack which includes contact(s)919, seal(s)913, and an end cap921. The X-ray identification925is configured to be radiopaque to X-radiation in order to aid in identifying the IPG10during an X-ray procedure.

FIG.10depicts the case17of the IPG10. The case17may include a feedthrough connector plate928including the first riser having the first set of capacitively coupled feedthrough pins and the second riser having the second set of feedthrough pins. A separate pin (e.g., P6) may be connected to the feedthrough connector plate928. Each of the pins may be configured to function as part of a signal carrying circuit for one of the patient electrodes20, antenna16, and case17. For example, certain pins are configured to connect to the antenna16while other pins are configured to connect to the lead frame927. The case17may include a first attachment opening10aand a second attachment opening10bconfigured to attach to the cassette923. The case may further include holders17aconfigured to hold the encapsulating material11awhen the material solidifies around the header11components.

FIG.11A-11Dshow different views of an alternative embodiment of a cassette950located in the IPG header11. The cassette950is configured to attach to the top of the case17of the IPG10and provides support for the antenna16and other components located in the header11. The cassette950includes a first attachment portion14and a second attachment portion15. The first attachment portion14is configured to attach to the first attachment opening10avia interference fit or press fit. The interference fit is configured to hold the first attachment portion14of the cassette within the first attachment opening10a.Preferably, the first attachment portion14may be configured as a post with a hexagonal cross-section in order to ensure correct alignment of the cassette and the case. However, other shapes and configurations of the first attachment portion may be employed as suitable to ensure a proper alignment and connection between the cassette and the case. The second attachment portion15is configured to be positioned within a second attachment opening10bof the case17. The second attachment portion15fits the second attachment opening10bwith some clearance to allow for positional flexibility of the cassette950relative to the case17, and to allow for an encapsulating material (e.g., epoxy)11ato further secure the cassette950to the case17. The second attachment portion15is preferably configured as a cylindrical post. However, other shapes and configurations of the second attachment portion may be employed as suitable to ensure a proper alignment and connection between the cassette and the case. For example, the cassette may be connected to the case with a single snap fit type attachment portion as an alternative to the two posts shown in the figures.

As shown inFIG.11C, the cassette950may also include support legs28. The support legs28are configured to minimize the contact between the cassette and the case and provide for additional space including a gap28afor encapsulating material11ato flow under the cassette950. The support legs are shown as a “v” shape inFIGS.11A-11D, but conical or other appropriate shape may be employed. The cassette950may includes upper projections29which are configured to providing for positioning attachment to the antenna16.

FIG.12Ais a perspective view of the antenna16andFIG.12Bshows the antenna fitted onto the cassette. The antenna is an inverted F type antenna having projection openings31configured to be coupled to the upper projections29of the cassette950. The antenna16may include one or more side wings32that extend downwardly along the cassette950to ensure stability and positioning of the antenna to the cassette950. The antenna16may alternatively be any of a variety of antennas such as but not limited to other patch antennas and the like. Such antennas are those suitable for compact portable devices which may be designed for UHF and microwave frequencies among others.

FIG.13depicts the lead frame927which may include four leads. Each of leads is a conductor configured to form part of an electrode circuit of the IPG. The conductor leads927a-927dmay be configured as generally flat or planar and may be positioned to extend along the top surface of the case17. At one end, each of the the conductor leads927a-927dmay be configured to bend upwardly and coil or wrap around one of the feedthrough pins to increase the surface area of the lead frame conductor in contact with the feedthrough pin. For example, as shown inFIG.13, each of the leads927a-927dmay include a curved end33a-33dcylindrically coiled to wrap around one of feedthrough pins. At the other end of the lead frame, each of the conductor leads927a-927dmay be configured to make electrical contact with a corresponding connector919or end cap921of the connector stack. Each conductor leads may include ends34a-34dthat bend upwardly to make contact with a corresponding connector919and the end cap921. The lead frame may be welded at one end to the feedthrough pins and at the other end to the connector stack to ensure the electrical connections are secure.

FIG.14depicts an exemplary connection of the antenna16and the lead frame927onto the feedthrough pins with the cassette omitted in order to improve visibility of the connection between the various electrical conductors. The antenna16may include a shorting arm16aconnected to one of the feedthrough pins (e.g., P1) and a feed arm16bconnected to another one of the feedthrough pins (e.g., P5). The connections between the antenna16and the feedthrough pins may be welded connections in order to ensure secure electrical connections. As shown inFIG.14, the conductor leads927a-927bmay each be connected to one of the feedthrough pins. For example, lead927amay be configured to connect to pin P8, conductor lead927bmay be configured to connect to pin P10, conductor lead927cmay be configured to connect to pin P11, and conductor lead927dmay be configured to connect to pin P9. The arrangement of and the number of the conductor leads927a-927dand/or pins P8-P11may be modified or altered as necessary depending upon the configuration of the IPG circuitry and the output of the pulse control module604.

Components or parts of embodiments described herein are exemplary and other known components or known designs to one or ordinary skill in the art may be utilized.

Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present disclosure.