Device for, and method of, neuromodulation with closed-loop micromagnetic hybrid waveforms to relieve pain

Abstract

A Closed Loop Hybrid Modulation Methodology, including the following four methods of neural stimulation: METHOD 1: A priming electrical signal followed by a second magnetic signal. METHOD 2: A magnetic priming signal followed by a second electrical signal. METHOD 3: A priming magnetic signal followed by a second magnetic signal. METHOD 4: A priming hybrid electric and magnetic signal followed by a second hybrid electric and magnetic signal.

Claims

1. A method of modulating an interaction between neurons with a closed-loop stimulator using magnetically induced evoked compound action potentials, the neurons including ganglions, neurovasculature, and glial cells, by: exposing the neurons and the ganglions to a first signal; the first signal lowering a depolarization threshold of the neurons; the first signal having a first signal parameter; exposing the neurons and the ganglions to a second signal; the second signal causing depolarization, leading to down-regulation via neuromodulation, thus relieving nociceptive and neuropathic pain; the second signal having a second signal parameter; sensing magnetically induced evoked compound action potential and late response; measuring evoked compound action potential and late response; adjusting the first signal parameter to improve lowering the depolarization threshold; adjusting the second signal parameter to improve depolarization; repeating the step of “exposing the neurons and ganglions to a first signal”; and repeating the step of “exposing the neurons and ganglions to a second signal”; whereby exposing the neurons and the ganglions to a first signal lowers the depolarization threshold and a second signal causing depolarization, leading to down-regulation via neuromodulation, thus relieving nociceptive and neuropathic pain.

2. The method of claim 1, where; the first signal parameter and the second signal parameter have a matching frequency, amplitude, phase polarity, relative phase, or harmonic content; or the first signal parameter and the second signal parameter have a different frequency, amplitude, phase polarity, relative phase, or harmonic content.

3. The method of claim 1, wherein the second signal is generated simultaneously with the first signal or the second signal is generated after the first signal has stopped.

4. The method of claim 1, wherein: the first signal is a varying electrical field applied by an electrode or a set of annular electrodes; or the first signal is a constant electrical field applied by an electrode or a set of annular electrodes.

5. The method of claim 1, wherein the first signal is an electrical field of between 0.040 and 1500 Hz, with a pulse width between 4 to 1000 μs.

6. The method of claim 1, wherein the second signal is a magnetic field with a sinusoidal waveform, created by one or more planar coils, cylindrical coils, or inductors.

7. The method of claim 1, wherein the second signal is a magnetic field with a half sinusoidal waveform created by one or more planar coils, cylindrical coils, or inductors, resulting in increased energy efficiency.

8. The method of claim 1, wherein the second signal is: a varying magnetic field created by one or more planar coils, cylindrical coils, or inductors; or a constant magnetic field created by one or more planar coils, cylindrical coils, or inductors.

9. A method of modulating an interaction between neurons—the neurons including nociceptors—ganglions, neurovasculature, and glial cells with a closed-loop stimulator by: exposing the neurons and the ganglions to a magnetic signal; the magnetic signal lowering a depolarization threshold of the neurons; the magnetic signal having a magnetic signal parameter; the magnetic signal generated one or more planar coils, cylindrical coils, or inductors; exposing the neurons and the ganglions to a second magnetic signal; the second magnetic signal causing depolarization, leading to down-regulation via neuromodulation, thus relieving nociceptive and neuropathic pain; the second magnetic signal having a magnetic signal parameter; sensing magnetically induced evoked compound action potential (ECAP); measuring ECAP via strength duration curves (Rheobase and Chronaxie); adjusting the magnetic signal parameter based on Rheobase, Chronaxie, and Late Response to improve depolarization; adjusting the magnetic signal parameter based on Rheobase and Chronaxie and Late Response to improve depolarization leading to down-regulation via neuromodulation, thus relieving nociceptive and neuropathic pain; and repeating the step of “exposing the neurons and ganglions to a magnetic signal”; whereby exposing the neurons and the ganglions to a magnetic signal to lower the depolarization threshold and a second magnetic signal causing depolarization to down-regulate the nociceptors causing a reduction in chronic pain.

10. The method of claim 9, wherein: an initial sinusoidal magnetic pulse is followed by a second one-half sinusoidal pulsed magnetic signal, timed such that the second magnetic signal triggers an action potential and depolarization leading to down-regulation via neuromodulation, thus relieving nociceptive and neuropathic pain.

11. The method of claim 9, wherein the magnetic signal is generated simultaneously with second magnetic signal or the second magnetic signal is generated after the magnetic signal has stopped.

12. The method of claim 9, wherein the step of “sensing a magnetically induced evoked compound action potential” is performed by reference electrodes.

13. The method of claim 9, wherein the step of “sensing a magnetically induced evoked compound action potential” is performed by a planar coil or cylindrical coil or inductor via induced electromotive force.

14. A neural stimulator for insertion into nervous system (central nervous system or peripheral nervous system) of a patient, the neural stimulator comprising: a lead; the lead having a proximal portion and a distal portion; and the distal portion able to unfold and expand after insertion into the patient; whereby the unfolded distal portion is wider than the proximal portion, thus permitting insertion of a lead that unfolds to a greater size than able to be directly inserted.

15. The neural stimulator for insertion into nervous system of a patient of claim 14 wherein; the lead is constructed of a biologically compatible material that causes the lead to unfold when the lead is warmed by body heat from the patient; whereby the lead automatically unfolds, reducing a number of steps that a surgeon must take to place the lead.

16. The neural stimulator for insertion into nervous system of a patient of claim 14, wherein: a planar coil is incorporated in a pseudoelastic memory metal or shape-memory polymer, the planar coil conforming to structure in a central or peripheral nervous system to provide more effective neuromodulation; or a cylindrical coil is incorporated in a pseudoelastic memory metal or shape-memory polymer, the cylindrical coil conforming to structure in a central or peripheral nervous system to provide more effective neuromodulation.

17. The neural stimulator for insertion into nervous system of a patient of claim 14, further comprising: a cylindrical coil housed in a circular disc that can rotate between 0 to 360 degrees, thus allowing the neural stimulator to steer electrical or eddy currents providing a neuromodulation effect; or a planar coil housed in a circular disc that tilts on one axis or several different axes, thus allowing the neural stimulator to steer electrical or eddy currents providing a neuromodulation effect.

18. The neural stimulator for insertion into nervous system of a patient of claim 15, further comprising: two or more magnets that interact to hold a first medial portion of the lead to a second medial portion of a second lead as a means to increase a strength of a magnetic field.

19. The neural stimulator for insertion into nervous system of a patient of claim 14, further comprising: an implantable pulse generator connected to the lead.

20. The neural stimulator for insertion into nervous system of a patient of claim 14, further comprising: a nanogenerator that functions as an implantable pulse generator; the nanogenerator converting kinetic energy into electrical energy; the electrical energy used to charge the lead.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0131] The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:

[0132] FIG. 1A illustrates a view of a cylindrical (isodiametric) embodiment of the collapsible neural stimulator.

[0133] FIG. 1B illustrates a view of insertion of the collapsible neural stimulator that expands increasing in width.

[0134] FIG. 2 illustrates a view of a cylindrical (isodiametric) neural stimulator.

[0135] FIG. 3 illustrates an anatomical view of insertion of the collapsible neural stimulator.

[0136] FIG. 4 illustrates a close-up view of insertion of the collapsible neural stimulator.

[0137] FIG. 5 illustrates a schematic view of a first means of powering of the collapsible neural stimulator.

[0138] FIG. 6 illustrates a schematic view of a second means of powering of the collapsible neural stimulator.

[0139] FIG. 7 illustrates a schematic view of a third means of powering of the collapsible neural stimulator, integrated into the lead of the stimulator.

[0140] FIG. 8 illustrates a front isometric of an embodiment of the Closed-Loop Omnidirectional Neuromodulation with Eddy Currents (CLONE).

[0141] FIG. 9 illustrates a rear isometric of an embodiment Closed-Loop Omnidirectional Neuromodulation with Eddy Currents (CLONE).

[0142] FIG. 10 illustrates a front view and side view of an embodiment of Closed-Loop Omnidirectional Neuromodulation with Eddy Currents (CLONE).

[0143] FIG. 11 illustrates an isometric of a cylindrical (isodiametric) embodiment of the Closed-Loop Omnidirectional Neuromodulation with Eddy Currents (CLONE).

[0144] FIG. 12 illustrates a side view of a cylindrical (isodiametric) embodiment of the Closed-Loop Omnidirectional Neuromodulation with Eddy Currents (CLONE).

[0145] FIG. 13A illustrates a planar coil for use as an electrode.

[0146] FIG. 13B illustrates a cylindrical coil for use as an electrode.

[0147] FIG. 14A illustrates a full-circle annular electrodes with an upper half activated.

[0148] FIG. 14B illustrates a full-circle annular electrodes with a lower half activated.

[0149] FIG. 15 illustrates a triple electrical peak.

[0150] FIG. 16A illustrates it closed loop hybrid simulation showing optimal timing of electrical and magnetic pulses.

[0151] FIG. 16B shows closed loop hybrid simulation using only magnetic pulses.

[0152] FIG. 17 shows coinciding electric and magnetic field peaks to obtain the desired complementary effect.

BEST MODE FOR CARRYING OUT THE INVENTION

[0153] The present disclosure will be more completely understood through the following description, which should be read in conjunction with the drawings. In this description, like numbers refer to similar elements within various embodiments of the present disclosure. The skilled artisan will readily appreciate that the methods, apparatus and systems described herein are merely exemplary and that variations can be made without departing from the spirit and scope of the disclosure.

[0154] The techniques disclosed herein may be achieved with minimally invasive procedures which are preferred over those that require extensive surgical intervention and healthcare expenses although in particular circumstances, a surgical implantation may be required. In an embodiment, a lead comprises a cylindrical arrangement of multiple electrodes, e.g., between 2 and 64. The diameter of the lead may be small enough to allow for percutaneous implantation into the spinal canal using an epidural needle under standard clinical practice. The electrodes are made of biocompatible materials such as titanium nitride, boron-doped diamond (BDD), poly(3,4-ethylenedioxythiophene (PEDOT), thiol-ene acrylate polymers, Silicon Carbide, platinum-iridium alloys, which are also resistant to corrosion. For example, a 50 cm long lead implemented with eight electrodes may have a diameter of 1.35 mm, with each cylindrical (isodiametric) electrode having a length of 3.0 mm, and a spacing between electrodes of 4.0 mm. Conducting wires may run from the electrodes to the distal part of the lead into metal connectors. The wires may be enclosed within a triple-insulated containment made of a biocompatible material, such as a pseudoelastic memory metal or SMP.

[0155] Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.

[0156] Referring to FIGS. 1A and 1B, a view of a cylindrical (isodiametric) embodiment of the collapsible neural stimulator is shown.

[0157] The collapsible neural stimulator 1 includes a guide wire 10, a sheath 12 with electrodes 50 placed along the lead 14 (see FIG. 2).

[0158] The body 30 folds along the first hinge 32 and the second hinge 34.

[0159] The collapsible neural stimulator 1 is formed from a main section 60, with first arm 62, second arm 64, and folding ramp 66.

[0160] Referring to FIG. 2, a view of insertion of the collapsible neural stimulator is shown.

[0161] The collapsible neural stimulator 1 is inserted percutaneously through the epidural space between the vertebrae 206 (see FIG. 2). A guide tube 15 directs the lead 14 between vertebrae T12 and L1 (see FIG. 2). This insertion point is only shown by way of example.

[0162] Referring to FIGS. 3 and 4, an anatomical view and a close-up view of insertion of the collapsible neural stimulator are shown.

[0163] The collapsible neural stimulator 1 is inserted into the patient 200, through the skin 202 and into the spine 204, between the vertebral foramen 206 using a percutaneous epidural approach, placement guided by use of a spinal needle 13.

[0164] The lead 14 passes over a guidewire 10 and within a guide tube 15 until in position.

[0165] Referring to FIGS. 5, 6, and 7, three schematic views of means of powering of the collapsible neural stimulator are shown.

[0166] In FIG. 5, the power and control unit 160 is fully internal. One or more piezoelectric generators 70, each including a cantilever arm 72 and weight 74, generate electricity for storage in the IPG 90. This power is carried to the collapsible neural stimulator 1 using a power transmission cable 92.

[0167] In FIG. 6, power is provided by a triboelectric generator 80. The motion of a first element 82 with respect to a second element 84 creates power for storage in the IPG 90, again carried to the collapsible neural stimulator 1 using a power transmission cable 92.

[0168] In FIG. 7, power is provided by a triboelectric generator 80, but the triboelectric generator 80 is now integrated into body of the collapsible neural stimulator 1. As before, the motion of a first element 82 with respect to a second element 84 creates power for storage in the IPG 90.

[0169] Referring to FIGS. 8 through 10, a second embodiment of the neural stimulator is shown.

[0170] The nerve stimulator 100 includes a body 102 with optional arms 104 that include suture holes 106.

[0171] The nerve stimulator 100 is connected to implantable pulse generator via the electrical contacts 110. The contacts no carry electrical signals to and from the nerve stimulator 100 across the array via wires 112.

[0172] The leads connect to the components of the nerve stimulator 100, including one or more recording/reference electrodes 120, a first magnetic planar coil 122, a second magnetic planar coil 124, an anode 126, and a cathode 128.

[0173] During operation, an implantable pulse generator causes the first magnetic planar coil 122 and the second magnetic planar coil 124 to emit magnetic signals, and the anode 126 and cathode 128 to emit electrical signals. The resulting evoked compound action potential is sensed by the recording/reference electrodes 120, which is reported back to the implantable pulse generator. The implantable pulse generator processes the resulting data, calculates a response, and issues a follow-up set of magnetic and electrical signals. This process repeats as the implantable pulse generator continues to optimize signaling to result in the most-effective pain reduction while managing power consumption to conserve its power reserves.

[0174] Referring to FIGS. 11 and 12, a cylindrical (isodiametric) embodiment of the collapsible neural stimulator is shown.

[0175] Again shown are a nerve stimulator 100 with body 102, recording/reference electrodes 120, a first magnetic cylindrical coil 123, a second magnetic cylindrical coil 125, an anode 126, and a cathode 128.

[0176] Referring to FIGS. 13A and 13B, exemplary coils are shown. Embodiments of the electrodes 50 include planar coil 130 and cylindrical coil 132.

[0177] Planar coil 130 is housed within cylindrical disc placed at the location of an electrode 50. The planar coil 130 can tilt about one or more axes, allowing the planar coil 130 to be best positioned to steer the electrical or eddy currents. The result is neuro modulation between neurons—the neurons including nociceptive and neuropathic pain—ganglions, neurovasculature, and glial cells. Correctly positioning the planar coil 130 may be performed in conjunction with a 3D software program with epidural ultrasound above, postoperative imaging, or both.

[0178] Cylindrical coil 132 it is housed within its logical disk placed at the location of an electrode 50. The cylindrical coil 132 can rotate within its plane, allowing the cylindrical coil 132 to be best positioned to steer the electrical or eddy currents.

[0179] The result is neuro modulation between neurons—the neurons including nociceptive and neuropathic pain—ganglions, neurovasculature, and glial cells. Correctly positioning the planar coil 130 may be performed in conjunction with a 3D software program with epidural ultrasound above, postoperative imaging, or both.

[0180] FIGS. 14A and 14B illustrate a full-circle annular electrodes alternating between lower half activation and upper half activation.

[0181] Outer annular electrode 60 is shown alternating between outer annular electrode first segment 62 activation, FIG. 14B, and outer annular electrode second segment 64 activation, FIG. 14A.

[0182] Outer annular electrode 60 surrounds inner electrode 66.

[0183] The outer electrode 66 is segmented to create between 2 and 64 doublets, or between 1 and 32 pairs. Each individual electrode can act as either an anode or a cathode, steering the electrical current to the magnetic field peak. The timing of the electrical field and magnetic field pulses must coincide such that the combined effect of each subthreshold pulse will trigger an action potential.

[0184] The pairs of outer electrodes 60, in total, have the same surface area as the inner electrode 66. The charges are balanced due to the equivalent surface areas. Alternatively, the pairs of outer electrodes 60, in total, have a different surface area than inner electrode 66, and the difference in surface area is compensated for by varying the current. By increasing the charge applied to the smaller surface area, the electrode can balance its charge with a lesser current applied to a larger surface area. The higher surface charge density of the smaller surface area electrode can be restricted to not exceed a given desired or safety maximum, such as 30 μC/cm2.

[0185] FIG. 15 illustrates a triple electrical peak.

[0186] The electrical peaks between two annular electrodes—inner and outer—are further divided into a circular peak between the two electrodes, rather than a single linear peak with a linear electrode array; in a slice plot, the circular peak appears as three electrical peaks, providing a superior means to achieve more precise steering to coincide the electric field and magnetic field peaks.

[0187] FIG. 16A illustrates it closed loop hybrid simulation showing optimal timing of electrical and magnetic pulses.

[0188] An electrical prime 170 is followed by a magnetic sine wave pulse 174, creating an action potential 178 and a magnetically induced ECAP 180.

[0189] FIG. 16B illustrates it closed loop hybrid simulation using only magnetic pulses.

[0190] The magnetic prime 172 is followed by a magnetic half sine wave pulse 176, creating an action potential 178 and a magnetically induced ECAP 180

[0191] Referring to FIG. 17, coinciding electric and magnetic field peaks to obtain the desired complementary effect.

[0192] Modeling shows that the planar spiral produces a peak magnetic field of 3 mT at the center of the coil, reduced to 0.3 mT at the distance of the dorsal column.

[0193] Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.

[0194] It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof.