Inferring lead placement based on sensed biomarkers

Abstract

A system may include an electrode arrangement and a neurostimulator. The electrode arrangement may have a length typically in a head-tail direction and a width typically in an inboard and outboard direction. The electrode arrangement may include a first set of electrodes and a second set of electrodes spaced apart over a width. The neural stimulator may be configured to stimulate a series of locations of the patient using a subset of the first set of electrodes and, for each stimulated location in the series of stimulated locations, identify a respective response measure for each of the second set of electrodes. Physiological midlines may be inferred or identified from these measurements, which may be used to guide lead placement and / or programming.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 527,220, filed July 17, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] This document generally relates to medical systems, and more specifically, but not in a restrictive manner, to systems, devices, and methods for determining the physiological midline of the spinal cord, which can be used for electrode placement or for programming or reprogramming stimulation therapies. Background Technology

[0004] Neuromodulation has been proposed as a therapy for a variety of conditions. Generally, neuromodulation and neurostimulation are used interchangeably to describe excitatory stimuli that elicit action potentials, as well as inhibitory and other effects. Examples of neuromodulation include spinal cord stimulation (SCS), deep brain stimulation (DBS), peripheral nerve stimulation (PNS), and functional electrical stimulation (FES). By way of example, and not limitation, SCS has been used to treat chronic pain syndromes. SCS is routinely used as a pain management therapy, but it is also implemented in conjunction with other treatments.

[0005] Some neural targets can be complex structures containing different types of nerve fibers. An example of such complex structures is the neuronal elements within and around the spinal cord targeted by the SCS. Furthermore, the number of available electrodes, combined with the ability to generate various complex electrical waveforms (e.g., pulses), presents clinicians or patients with a vast selection of modulation parameter sets. For example, if the neural modulation system to be programmed has 16 electrodes, millions of modulation parameter sets are available for programming into the system. The SCS system is implanted using surgery, which places one or more leads near the spinal cord, and the neurostimulator is implanted under the skin. Although one or more SCS leads have multiple electrodes that provide flexibility in programming the size, shape, and location of the neural modulation field, the one or more leads must still be properly positioned so that the neurostimulator can be programmed to deliver effective neural modulation energy to the correct nerves for the desired therapy.

[0006] The dorsal column (DC) fibers within the spinal cord exhibit somatic organization on the medial and lateral sides, necessitating consideration of medial and lateral placement of electrode arrangements for the spinal cord sclera (SCS). For instance, knowing the location of the physiological midline relative to the electrode arrangement helps predict activation and clinical outcomes and facilitates the directing of stimulation to the correct dermatome. Therefore, stimulation prediction algorithms and closed-loop stimulation algorithms can utilize physiological midline information.

[0007] Some systems may use image-guided techniques (such as fluoroscopy) to guide placement indicated by leads on the user interface, which can then be used to program a neurostimulator to stimulate a target. However, image-guided techniques can introduce inaccuracies because radiologists can arbitrarily position and orient the fluoroscope relative to the patient. Therefore, the imaging angle and image quality depend heavily on the angle at which the radiologist sets the fluoroscope. Summary of the Invention

[0008] Various embodiments of this subject can be used to infer the placement of a lead relative to the physiological midline by stimulating the spinal cord at different points, then sensing at different points in the spinal cord to infer the midline location, and recommending new lead placements or adjusting stimulation or anticipated stimulation based on the inferred midline.

[0009] Examples of systems (e.g., Example 1) may include an electrode arrangement and a neurostimulator configured to be connected to the electrode arrangement. The electrode arrangement may be configured to be positioned near the patient's spine. The electrode arrangement has a length generally in the head-to-tail direction of the patient and a width generally in the medial-lateral direction of the patient. The electrode arrangement may include a first set of electrodes spaced across the width and a second set of electrodes spaced across the width. The neurostimulator may be configured to stimulate a series of locations of the patient using a subset of the first set of electrodes, and for each stimulated location in the series of stimulated locations, identify a corresponding response measure for each subset of electrodes within the second set. The series of stimulated locations may include at least a first location and a second location, and the second set of electrodes may include at least a first subset of electrodes and a second subset of electrodes. For the first location, the corresponding response measure may include a first first location response measure for the first subset of electrodes and a second first location response measure for the second subset of electrodes. For the second location, the corresponding response measure may include a first second location response measure for the first subset of electrodes and a second second location response measure for the second subset of electrodes. The system can be configured to identify the physiological midline based on a corresponding response measure for each of a series of stimulated locations. A first “first location” response measure and a second “first location” response measure can be recorded or measured simultaneously or at different times. Similarly, a first “second location” response measure and a second “second location” response measure can be recorded or measured simultaneously or at different times. The subset of electrodes within the second electrode set can include, for example, a single electrode suitable for monopolar sensing, or two (or more) electrodes suitable for differential sensing.

[0010] In Example 2, the subject described in Example 1 may optionally be configured such that the neurostimulator is configured to identify the physiological midline.

[0011] In Example 3, any one or more of the subjects described in Examples 1-2 may optionally be configured such that the system includes a programmer configured to program the neurostimulator and to identify the physiological midline.

[0012] In Example 4, the subject matter described in Example 3 can optionally be configured such that the programmer is configured to program the neurostimulator using the identified physiological midline.

[0013] In Example 5, any one or more of the topics described in Examples 3-4 may optionally be configured such that the programmer is configured to compare changes in the corresponding response measure to detect relative movement between the spine and the electrode arrangement, and to reprogram the neurostimulator connected to the electrode arrangement based on the detected relative movement. The relative movement may be caused by lead migration and / or spinal movement, such as that that may occur during activity or postural changes.

[0014] In Example 6, any one or more of the topics described in Examples 3-5 may optionally be configured such that the programmer includes a display and is configured to provide a plot on the display of the corresponding response measure for each stimulated location. The displayed plot may be used to identify the physiological midline.

[0015] In Example 7, any one or more of the subjects described in Examples 1-6 may optionally be configured such that the neurostimulator is configured to stimulate the series of locations by moving at least one pole for delivering stimulation energy to stimulate the series of locations. The pole may be a single pole, such as a cathode or anode. The pole may include a bipolar, shielded tripolar, or other electrode geometries that can be moved to stimulate the series of locations.

[0016] In Example 8, the subject described in Example 7 may optionally be configured such that the at least one pole includes a bipolar, the neurostimulator is configured to stimulate the series of locations by moving the bipolar for delivering stimulation energy to stimulate the series of locations, and the bipolar includes a cathode and an anode.

[0017] In Example 9, the subject described in Example 7 may optionally be configured such that the at least one pole includes a mediolateral guarded tripole, the neurostimulator is configured to stimulate the series of locations by stimulating at least some of the locations using the mediolateral guarded tripole, and the mediolateral guarded tripole includes a cathode typically between at least two anodes.

[0018] In Example 10, the subject described in Example 7 may optionally be configured such that the at least one pole includes a monopole for stimulating at least some of the locations.

[0019] In Example 11, the subject matter described in Example 7 can optionally be configured such that the electrode arrangement includes at least a third set of electrodes spaced across the width. For each stimulated location in a series of stimulated locations, the neurostimulator can be configured to identify a corresponding response measure for each subset of electrodes within the third set, and the system can be configured to identify the physiological midline based on the corresponding response measures for each subset of electrodes within the second set and for each subset of electrodes within the third set. Alternatively, for each stimulated location in a series of stimulated locations, the neurostimulator can be configured to form corresponding differential pairs for sensing using corresponding electrodes within the second and third sets, and to use the corresponding differential pairs to identify the corresponding response measure.

[0020] In Example 12, the subject described in Example 11 may optionally be configured such that the programmer is configured to perform trend plotting across rows of the second electrode set and the at least third electrode set to infer the alignment of the lead with the physiological midline.

[0021] In Example 13, the subject described in Example 11 may optionally be configured such that the programmer is configured to perform trend plotting along the respective columns of the electrodes in the second electrode set and at least the third electrode set.

[0022] In Example 14, any one or more of the subjects described in Examples 1-13 may optionally be configured such that the electrode arrangement is located on a paddle lead, and the electrode arrangement includes at least three columns of electrodes.

[0023] In Example 15, any one or more of the topics described in Examples 1-14 may optionally be configured such that the corresponding response measure includes a measure of at least one characteristic of the induced composite action potential (ECAP), the characteristic being selected from amplitude, area under the curve (AUC), curve length (CL), power spectrum characteristics, small wave characteristics, correlation with the template, recursion with known parameters, or at least one delay between different channels.

[0024] Example 16 includes topics such as methods, means of performing actions, machine-readable media including instructions that cause a machine to perform actions when executed by a machine. The topics can be performed using an electrode arrangement located near a patient's spine, wherein the electrode arrangement has a length generally in the head-to-tail direction of the patient and a width generally in the medial-lateral direction of the patient. The electrode arrangement may include a first set of electrodes spaced across the width and a second set of electrodes spaced across the width. The method may include stimulating a series of locations of the patient using a subset of the first set of electrodes, and for each stimulated location in the series of stimulated locations, identifying a corresponding response measure for each subset of electrodes within the second set of electrodes. The series of stimulated locations may include at least a first location and a second location, and the second set of electrodes may include at least a first subset of electrodes and a second subset of electrodes. For the first location, the corresponding response measure may include a first first location response measure for the first subset of electrodes and a second first location response measure for the second subset of electrodes. For the second location, the corresponding response measure may include a first second location response measure for the first subset of electrodes and a second second location response measure for the second subset of electrodes. The method may further include identifying the physiological midline based on a corresponding response measure for each of a series of stimulated locations. The first “first location” response measure and the second “first location” response measure may be recorded or measured simultaneously or at different times. The first “second location” response measure and the second “second location” response measure may also be recorded or measured simultaneously or at different times. A subset of electrodes within the second electrode set may include, for example, a single electrode suitable for monopolar sensing, or two (or more) electrodes suitable for differential sensing.

[0025] In Example 17, the subject described in Example 16 may optionally be configured such that stimulating the series of locations includes moving at least one pole for delivering stimulus energy to stimulate the series of locations.

[0026] In Example 18, the subject described in Example 17 may optionally be configured such that the pole may include a bipolar pole, and stimulating the series of locations includes moving the bipolar pole for delivering stimulus energy to stimulate the series of locations, the bipolar pole including a cathode and an anode.

[0027] In Example 19, the subject matter described in Example 17 may optionally be configured such that the electrode may include an inner and outer shielded triode, stimulating the series of locations includes stimulating at least some of the locations using the inner and outer shielded triode, and the inner and outer shielded triode includes a cathode typically between at least two anodes.

[0028] In Example 20, the subject described in Example 17 may optionally be configured such that the pole may include a monopole for stimulating at least some of the locations.

[0029] In Example 21, the subject matter described in Example 17 can optionally be configured such that the electrode arrangement includes at least a third set of electrodes spaced across the width. Identifying the corresponding response measure for each stimulated location in a series of stimulated locations may include identifying a corresponding response measure for each subset of electrodes within the third set of electrodes, and the system may be configured to identify the physiological midline based on the corresponding response measures for each subset of electrodes within the second set of electrodes and for each subset of electrodes within the third set of electrodes. Alternatively, identifying the corresponding response measure for each stimulated location in a series of stimulated locations may include forming corresponding difference pairs for sensing using the corresponding electrodes within the second set of electrodes and the third set of electrodes, and using the corresponding difference pairs to identify the corresponding response measure.

[0030] In Example 22, the subject described in Example 21 may optionally be configured to further include comparing trend plots of rows across the second electrode set and the at least third electrode set to infer the alignment of the lead with the physiological midline.

[0031] In Example 23, the subject described in Example 21 may optionally be configured to also include trend plotting comparing individual columns of electrodes across the second electrode set and the at least third electrode set.

[0032] In Example 24, any one or more of the subjects described in Examples 16-23 may optionally be configured such that the first electrode set is close to the head end of the electrode arrangement and the second electrode set is close to the tail end of the electrode arrangement.

[0033] In Example 25, any one or more of the subjects described in Examples 16-24 may optionally be configured such that the electrode arrangement is located on the paddle lead.

[0034] In Example 26, any one or more of the subjects described in Examples 16-25 may optionally be configured such that the electrode arrangement includes at least three columns of electrodes.

[0035] In Example 27, any one or more of the subjects described in Examples 16-26 may optionally be configured such that the electrode arrangement includes multiple rows of electrodes, and at least some of the electrodes in the multiple rows are staggered relative to each other.

[0036] In Example 28, any one or more of the topics described in Examples 16-27 may optionally be configured such that the corresponding response measure includes a measure of at least one characteristic of the induced compound action potential (ECAP), the characteristic being selected from amplitude, area under the curve (AUC), curve length (CL), power spectrum characteristics, small wave characteristics, correlation with the template, recursion with known parameters, or at least one delay between different channels.

[0037] In Example 29, any one or more of the subjects described in Examples 16-28 may optionally be configured to also include a neurostimulator programmed to be connected to the electrode arrangement to deliver neural modulation using the identified physiological midline.

[0038] In Example 30, any one or more of the topics described in Examples 16-29 may optionally be configured to further include comparing changes in the corresponding response measure to detect lead migration and reprogramming the neurostimulator connected to the electrode arrangement based on the detected lead migration.

[0039] In Example 31, any one or more of the topics described in Examples 16-30 may optionally be configured to also include a plot displaying the corresponding measure of response for each stimulated location. The displayed plot can be used to identify the physiological midline.

[0040] Example 32 includes a subject (such as a non-transitory machine-readable medium including instructions that, when executed by a machine, cause the machine to perform a method using an electrode arrangement located near the patient's spine). The electrode arrangement may have a length generally in the head-to-tail direction of the patient and a width generally in the medial-lateral direction of the patient. The electrode arrangement may include a first set of electrodes spaced across the width and a second set of electrodes spaced across the width. The method performed using the machine may include stimulating a series of locations on the patient using a subset of the first set of electrodes, and for each stimulated location in the series of stimulated locations, identifying a corresponding response measure for each subset of electrodes within the second set. The series of stimulated locations may include at least a first location and a second location, and the second set of electrodes may include at least a first subset of electrodes and a second subset of electrodes. For the first location, the corresponding response measure may include a first first location response measure for the first subset of electrodes and a second first location response measure for the second subset of electrodes. For the second location, the corresponding response measure may include a first second location response measure for the first subset of electrodes and a second second location response measure for the second subset of electrodes. The method may further include identifying the physiological midline based on a corresponding response measure for each of a series of stimulated locations. The first “first location” response measure and the second “first location” response measure may be recorded or measured simultaneously or at different times. The first “second location” response measure and the second “second location” response measure may also be recorded or measured simultaneously or at different times. A subset of electrodes within the second electrode set may include, for example, a single electrode suitable for monopolar sensing, or two (or more) electrodes suitable for differential sensing.

[0041] In a further example, the subject described in Example 32 can be configured such that the method executed by the machine can include any of the subjects described in Examples 17-32.

[0042] For example, in Example 33, the subject described in Example 32 may optionally be configured such that the method performed by the machine further includes identifying the physiological midline based on a corresponding response measure for each of the stimulated locations in a series of stimulated locations.

[0043] For example, in Example 34, the subject described in Example 32 may optionally be configured such that the electrode arrangement is located on a paddle lead, and the electrode arrangement includes at least three columns of electrodes.

[0044] For example, in Example 35, the subject described in Example 32 may optionally be configured such that the corresponding response measure includes a measure of at least one characteristic of the induced composite action potential (ECAP), the characteristic being selected from amplitude, power spectrum characteristics, small wave characteristics, correlation with the template, recursion with known parameters, or at least one delay between different channels.

[0045] This summary is an overview of some of the teachings of this application and is not intended to be an exclusive or exhaustive treatment of the subject matter. Further details regarding the subject matter are found in the detailed description and the appended claims. Other aspects of this disclosure will be apparent to those skilled in the art upon reading and understanding the following detailed description and examining the accompanying drawings, which form a part of it, and each of the drawings should not be construed as limiting. The scope of this disclosure is defined by the appended claims and their legal equivalents. Attached Figure Description

[0046] Various embodiments are illustrated by way of example in the accompanying drawings. These embodiments are exemplary and are not intended to be exhaustive or exclusive embodiments of the subject matter.

[0047] Figure 1 An embodiment of the neural modulation system is shown by way of example rather than limitation.

[0048] Figure 2 Embodiments of modulation devices are shown, such as those that can be used in modulation devices. Figure 1 The modulation device implemented in the neural modulation system.

[0049] Figure 3 An embodiment of a programming system, such as a programming device, is shown, which can be implemented as... Figure 1 Programming devices in neural modulation systems.

[0050] Figure 4 An example of an implementation of the SCS system, also known as a Spinal Cord Modulation (SCM) system, is shown.

[0051] Figure 5 An example of an electrode arrangement with a set of stimulating electrodes and a set of recording electrodes is shown by way of example rather than limitation.

[0052] Figure 6 This method of identifying the midline using responses to a range of locations stimulated is shown through examples rather than limitations.

[0053] Figure 7 Examples, rather than limitations, are shown to be suitable for use with stimulation electrodes (e.g., Figure 5 The first set in the middle) or recording electrodes (e.g., Figure 6 The exclusive electrode subset of the second set in the group.

[0054] Figure 8 Examples, rather than limitations, are shown to be suitable for use with stimulation electrodes (e.g., Figure 5 The first set in the middle) or recording electrodes (e.g., Figure 6 The non-exclusive electrode subset of the second set in the [context].

[0055] Figure 9 This example, rather than a limitation, illustrates how a second set of electrodes records responses when stimulating a range of locations using a subset of the first set of electrodes.

[0056] Figure 10 A paddle-type lead is shown by way of example rather than limitation, which shifts the target bipolar on the inner and outer sides while simultaneously recording from other contacts.

[0057] Figure 11 A paddle-type lead is shown by way of example rather than limitation, which shifts the inner and outer protective triodes on the inner and outer sides while recording from other contacts.

[0058] Figure 12 The paddle-type lead is illustrated by way of example rather than limitation, showing how to construct a plotted paddle in the head-to-tail direction.

[0059] Figure 13 Measurements of internal and external biomarkers are shown by way of example rather than limitation.

[0060] Figure 14 Physiological midline identification and recommendations are shown through examples rather than restrictions.

[0061] Figure 15 The characteristic variations based on the inner and outer displacements from the midline are shown by way of example rather than limitation.

[0062] Figure 16 The characteristic response to right-inward and outward propeller displacements is shown by way of example rather than limitation.

[0063] Figure 17 The characteristic response of a correctly positioned paddle is shown through examples rather than limitations.

[0064] Figure 18 The characteristic response to leftward and inward / outward paddle displacements is shown by way of example rather than limitation.

[0065] Figure 19 The effect of increasing the amplitude of the evoked stimulus is shown through examples rather than limitations.

[0066] Figure 20Stimulus configurations are illustrated by way of example rather than limitation. In this non-limiting example used for modeling the response, the inner and outer stimulus sweeps can move from the left bipolar to the left tripolar, then to the extended tripolar, to the right tripolar, and finally to the right bipolar.

[0067] Figure 21 The displacement of the left lead midline and the average differential sensing at two levels induced in response to a 3mA stimulus are shown by way of example rather than limitation.

[0068] Figure 22 The midline displacement of the paddle centering induced in response to a 3mA stimulus and the average differential sensing at two levels are shown by way of example rather than limitation.

[0069] Figure 23 The midline displacement of the right lead induced by a midline displacement in response to a 3mA stimulus and the average differential sensing at two levels are illustrated by way of example rather than limitation.

[0070] Figure 24 The stimulation of the paddle-shaped lead's rotation is shown through examples rather than limitations.

[0071] Figure 25 Interpolation based on the sensing touchpoints of the nearest grid point is shown by way of example rather than limitation.

[0072] Figure 26 A graph is shown by way of example rather than limitation, illustrating how rotation of a paddle lead along an inside-outside-head-tail path can be detected using three pairs of contacts on the same paddle lead.

[0073] Figure 27 The rotation angle of the paddle lead relative to the centerline is shown by way of example rather than limitation. Detailed Implementation

[0074] The following detailed description of this subject matter takes into account the accompanying drawings, which illustrate, by way of example, specific aspects and embodiments in which the subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the subject matter. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the subject matter. References to “a,” “an,” or “various” embodiments in this disclosure are not necessarily references to the same embodiment, and such references contemplate more than one embodiment. Therefore, the following detailed description is not restrictive and its scope is defined only by the appended claims and the full scope of their legal equivalents.

[0075] This subject matter can be used to determine absolute or relative offset from the physiological midline based on biomarker / electrophysiological measurements and to use these measurements for programming purposes. These measurements capture the response to stimulation at a series of locations medial and lateral to the spine. For at least some of these locations, stimulation can induce action potentials along the dorsal column (DC) fibers, which can be measured using additional electrodes on the leads. The midline can be inferred or identified based on medial-lateral recursion of biomarker signals. Medial-lateral lead migration can be identified based on changes in relative measurements between two or more medial-lateral offset contacts or leads. Furthermore, in some embodiments, the dorsoventral side can also be identified. The system can be configured to use this information to recommend programming or reprogramming.

[0076] Figure 1 Embodiments of a neural modulation system are illustrated by way of example, not limitation. The illustrated system 100 includes electrodes 101, a modulation device 102, and a programming system such as a programming device 103. The programming system may include multiple devices. Electrode 101 is configured to be placed on or near one or more neural targets in a patient. Modulation device 102 is configured to be electrically connected to electrode 101 and deliver neurally modulated energy, such as in the form of electrical pulses, to one or more neural targets through electrode 101. A stimulation configuration is used to control the delivery of neural modulation. The stimulation configuration may include a set of modulation parameters to specify an electrical waveform (e.g., a pulse or pulse pattern or other waveform shape). The stimulation configuration may also include electrode configurations (e.g., selection of active electrodes through which the electrical waveform is delivered, the polarity of the active electrodes, and fractionation used to determine the energy distribution in the active electrodes). The set of modulation parameters may also define the electrode configuration. The stimulation configuration may also include pulse timing information (e.g., time delay and phase offset of the stimulation channel). In various embodiments, at least some of the multiple modulation parameters may be programmable by a user, such as a physician or other caregiver. Programming device 103 provides the user with access to user-programmable parameters. In various embodiments, the programming device 103 is configured to be communicatively coupled to the modulation device via a wired or wireless link. In various embodiments, the programming device 103 includes a graphical user interface (GUI) 104 that allows a user to set and / or adjust values ​​of user-programmable modulation parameters.

[0077] Figure 2 An embodiment of modulation device 202 is shown, such as that which can be used in modulation devices 202. Figure 1The modulation device 202 is implemented in the neural modulation system 100. An illustrated embodiment of the modulation device 202 includes a modulation output circuit 205 and a modulation control circuit 206. Those skilled in the art will understand that the neural modulation system may include additional components such as sensing circuitry, telemetry circuitry, and power for feedback control of patient monitoring and / or treatment. The modulation output circuit 205 generates and delivers neural modulation. Neural modulation pulses are provided herein as examples. However, the subject matter is not limited to pulses but may include other electrical waveforms (e.g., waveforms with different waveform shapes, and waveforms with various pulse patterns). The modulation control circuit 206 controls the delivery of the neural modulation pulses using multiple modulation parameters. The lead system 207 includes one or more leads, each configured to be electrically connected to the modulation device 202 and a plurality of electrodes 201-1 to 201-N distributed in an electrode arrangement using the one or more leads. Each lead may have an electrode array consisting of two or more electrodes (which may also be referred to as contacts). Multiple leads can provide multiple electrode arrays to provide an electrode arrangement. Each electrode is a single conductive contact that provides an electrical interface between the modulation output circuitry 205 and the patient tissue, where N 2. The neural modulation pulses are each delivered from the modulation output circuit 205 via a set of electrodes selected from electrodes 201-1 to 201-N. The number of leads and the number of electrodes on each lead may depend, for example, on the distribution of the targets for neural modulation and the need to control the electric field distribution at each target. In one embodiment, by way of example and not limitation, the lead system includes two leads, each with eight electrodes. Some embodiments may use a lead system including paddle-type leads.

[0078] The actual number and shape of the leads and electrodes can vary depending on the intended application. An implantable waveform generator may include a housing for housing electronics and other components. The housing may be made of a conductive, biocompatible material, such as titanium, forming a sealed compartment in which the internal electronics are protected from body tissue and fluids. In some cases, the housing may serve as electrodes (e.g., shell electrodes). The waveform generator may include electronic components such as a controller / processor (e.g., a microcontroller), memory, a battery, telemetry circuitry, monitoring circuitry, modulation output circuitry, and other suitable components known to those skilled in the art. The microcontroller executes a suitable program stored in memory to guide and control the neural modulation performed by the waveform generator. Stimulation configuration determines how energy is delivered through the electrodes. Stimulation configuration may include a set of modulation parameters, which may include amplitude, pulse width and frequency, electrode configuration (which may include fractionation and polarity), and pulse timing (which may include time delay and phase shift). Electrically modulated energy is provided to the electrodes according to the set of modulation parameters programmed into the pulse generator. By way of example, but not limitation, the electrically modulated energy may be in the form of a pulsed electrical waveform. The stimulation configuration may include an electrode set defining electrodes that are activated as anodes (positive), cathodes (negative), and off (zero), a percentage of modulation energy allocated to each electrode (detailed electrode configuration), and electrical pulse parameters defining the pulse amplitude (measured in milliamperes or volts, depending on whether the pulse generator supplies a constant current or a constant voltage to the electrode array), pulse width (measured in microseconds), pulse rate (measured in pulses per second), and burst rate (measured as modulation-on duration X and modulation-off duration Y). Electrodes selected for transmitting or receiving electrical energy are referred to herein as “activated,” while electrodes not selected for transmitting or receiving electrical energy are referred to herein as “inactive.”

[0079] Electrical modulation occurs between or among multiple activated electrodes, one of which may be a waveform generator. The system may be able to deliver modulated energy to tissue in unipolar or multipolar (e.g., bipolar, tripolar, etc.) modes. Unipolar modulation occurs when a selected lead electrode is activated along with the housing of the waveform generator, causing modulated energy to be transferred between the selected electrode and the housing. Either the electrode or the housing electrode may be assigned up to k possible groups or timing “channels.” In one embodiment, by way of example and not limitation, k may be equal to four. The timing channels identify which electrodes are selected to synchronously inject or extract current to create an electric field in the tissue to be stimulated. The amplitude and polarity of the electrodes on the channels may differ. In particular, in any of the k timing channels, the electrode may be selected as positive (anode, injection), negative (cathode, extraction), or off (no current) polarity. The waveform generator can operate in a mode that delivers electrically modulated energy, which is therapeutically effective and causes the patient to perceive the energy delivery (e.g., treatment effectively relieves pain in the presence of perceived sensory abnormalities), and can operate in a sub-perceptual mode that delivers electrically modulated energy, which is therapeutically effective and does not cause the patient to perceive the energy delivery (e.g., treatment effectively relieves pain in the presence of unperceptible sensory abnormalities).

[0080] Waveform generators can be configured to individually control the amplitude of the current flowing through each electrode. For example, a current generator can be configured to selectively generate individual current-regulated amplitudes from independent current sources for each electrode. In some embodiments, the pulse generator can have a voltage-regulated output. While individually programmable electrode amplitudes are desirable for fine control, a single output source that switches across electrodes can also be used, although with less fine control in programming. Neural modulators can be designed with hybrid current and voltage regulation devices.

[0081] Neuromodulation systems can be configured to modulate spinal target tissue or other neural tissue. The configuration of electrodes used to deliver electrical pulses to the target tissue constitutes an electrode configuration, wherein the electrodes can be selectively programmed to act as an anode (positive), cathode (negative), or off (zero). In other words, the electrode configuration represents polarity as positive, negative, or zero. The electrode configuration can be used to control or alter the delivery of electrical waveforms. The electrical waveforms can be analog or digital signals. In some embodiments, the electrical waveforms include pulses. Pulses can be delivered in a regular, repetitive pattern, or pulses can be delivered using complex, seemingly irregular patterns. Other parameters that can be controlled or altered include the amplitude, pulse width, and rate (or frequency) of the electrical pulses. Each electrode configuration, along with the electrical pulse parameters, can be referred to as a "modulation parameter set." Each modulation parameter set, including a subdivided current distribution to the electrodes (as a percentage cathode current, a percentage anode current, or off), can be stored and combined into a modulation program that can then be used to modulate multiple areas within the patient.

[0082] The number of available electrodes, combined with the ability to generate a wide variety of complex electrical waveforms (e.g., pulses), presents clinicians or patients with a vast selection of modulation parameter sets. For example, if the neural modulation system to be programmed has 16 electrodes, millions of modulation parameter sets are available for programming into the neural modulation system. Furthermore, an SCS system, for example, can have 32 electrodes, which exponentially increases the number of modulation parameter sets available for programming. To facilitate such selection, clinicians typically program the modulation parameter sets via computerized programming systems, allowing the determination of optimal modulation parameters based on patient feedback or other means, and subsequently programming the desired modulation parameter set. Modulation device 202 can also be configured to use any one or more electrodes within lead system 207 to sense the electrical response.

[0083] Figure 3 An embodiment of a programming system, such as programming device 303, is shown, which can be implemented as... Figure 1 Programming device 103 in a neural modulation system. Programming device 303 includes storage device 308, programming control circuitry 309, and graphical user interface (GUI) 304. Programming control circuitry 309 generates multiple modulation parameters controlling the delivery of neural modulation pulses based on the pattern of the neural modulation pulses. In various embodiments, GUI 304 includes any type of presentation device, such as an interactive or non-interactive screen, and any type of user input device that allows a user to program the modulation parameters, such as a touchscreen, keyboard, keypad, touchpad, trackball, joystick, and mouse. Storage device 308 may store, among other things, modulation parameters to be programmed into the modulation device. Programming device 303 may transmit multiple modulation parameters to the modulation device. In some embodiments, programming device 303 may send power to the modulation device. Programming control circuitry 309 may generate multiple modulation parameters. In various embodiments, programming control circuitry 309 may check the values ​​of the multiple modulation parameters against safety rules to limit these values ​​within the constraints of the safety rules.

[0084] In various embodiments, a combination of hardware, software, and firmware may be used to implement one or more devices. For example, circuitry for a GUI, modulation control circuitry, and programmable control circuitry, including various embodiments of them discussed in this document, may be implemented using dedicated circuitry configured to perform one or more specific functions or general-purpose circuitry programmed to perform such functions. Such general-purpose circuitry includes, but is not limited to, microprocessors or portions thereof, microcontrollers or portions thereof, and programmable logic circuitry or portions thereof.

[0085] Figure 4An embodiment of the SCS system, also known as a spinal cord modulation (SCM) system, is illustrated by way of example. The SCS system 410 typically includes one or more (two illustrated) implantable neural modulation leads 411 (which may also be paddle leads), an electrical waveform generator 412, an external remote controller (RC) 413, a clinician's programmer (CP) 414, and an external trial modulator (ETM) 415. An IPG is used herein as an example of an electrical waveform generator. However, it is particularly noteworthy that the waveform generator can be configured to deliver regular, repetitive pulse patterns or complex patterns that appear to be irregular pulse patterns, where the pulses have different amplitudes, pulse widths, pulse intervals, and bursts with different numbers of pulses. It is also particularly noteworthy that the waveform generator can be configured to deliver electrical waveforms other than pulses. The waveform generator 412 may be physically connected to one or more neural modulation leads 411 via one or more percutaneous lead extensions 416, which carry multiple electrodes 417. As shown, the neural modulation lead 411 can be a percutaneous lead, with electrodes arranged in a row along the neural modulation lead. Any suitable number of neural modulation leads (including only one) can be provided, as long as the number of electrodes is greater than two (including the waveform generator housing used as a housing electrode) to allow for lateral current redirection. Alternatively, surgical paddle leads can be used instead of one or more percutaneous leads. In some embodiments, the waveform generator 412 may include a pulse generation circuit that delivers electrically modulated energy to the electrodes in the form of pulsed electrical waveforms (i.e., a time series of electrical pulses) according to a set of modulation parameters.

[0086] The ETM 415 can also be physically connected to the neural modulation lead 411 via a percutaneous lead extension 418 and an external cable 419. The ETM 415 may have waveform generation circuitry similar to that of the waveform generator 412 to deliver electrically modulated energy to the electrodes according to a set of modulation parameters. The ETM 415 is a non-implantable device used experimentally after the neural modulation lead 411 has been implanted and before the waveform generator 412 has been implanted to test the responsiveness of the modulation to be provided. The functionality described herein with respect to the waveform generator 412 can also be performed with respect to the ETM 415.

[0087] RC 413 can be used to telemetry control ETM 415 via bidirectional RF communication link 420. RC 413 can also be used to telemetry control waveform generator 412 via bidirectional RF communication link 421. This type of control allows waveform generator 412 to be turned on or off and programmed with different sets of modulation parameters. Waveform generator 412 can also be operated to modify the programmed modulation parameters to actively control the characteristics of the electrically modulated energy output by waveform generator 412. Clinicians can use CP 414 to program modulation parameters into waveform generator 412 and ETM 415 in the operating room and subsequent sessions. Waveform generator 412 can be implantable. Implantable waveform generator 412 and ETM 415 can have [specific features related to] [the specific ... Figure 2 The features discussed in the described modulation device 202 are similar to those of the features discussed in the original text.

[0088] CP 414 can communicate indirectly with waveform generator 412 or ETM 415 via IR communication link 422 or other links through RC 413. CP 414 can also communicate directly with waveform generator 412 or ETM 415 via RF communication link or other links (not shown). Detailed modulation parameters provided by CP 414 can also be used to program RC 413, allowing the modulation parameters to be subsequently modified by operating RC 413 in stand-alone mode (i.e., without the assistance of CP 414). Various devices can be used as CP 414. Such devices can include portable devices such as laptops, minicomputers, personal digital assistants (PDAs), tablets, telephones, or remote controls (RC) with extended functionality. Therefore, programming can be performed by executing software instructions contained within CP 414. Alternatively, such programming can be performed using firmware or hardware. In any event, CP 414 can actively control the characteristics of the electrical modulation generated by waveform generator 412 to allow the determination of desired parameters based on patient feedback or other feedback, and to subsequently program waveform generator 412 using the desired modulation parameters. To allow the user to perform these functions, CP 518 may include user input devices (e.g., a mouse and keyboard) and a programming display screen housed within a housing. In addition to or in place of a mouse, other directional programming devices may be used, such as a trackball, touchpad, joystick, touchscreen, or directional keys included as part of the keys associated with the keyboard. External devices (e.g., CP) can be programmed to provide a display screen that, among other functions, allows clinicians to select or enter patient profile information (e.g., name, date of birth, patient identifier, physician, diagnosis, and address), enter surgical information (e.g., programming / follow-up, implantation of experimental systems, implantation of waveform generators, implantation of waveform generators and leads, replacement of waveform generators, replacement of waveform generators and leads, replacement or modification of leads, transplantation, etc.), generate a patient pain map, define lead configuration and orientation, initiate and control the electrically modulated energy output from the neuromodulation leads, and select and program the IPG using modulation parameters in both surgical and clinical settings.

[0089] The external charger 423 can be a portable device for percutaneous charging of the waveform generator via a wireless link (such as an inductive link 424). Once the waveform generator has been programmed and its power supply has been charged by the external charger or otherwise supplemented, the waveform generator can operate as programmed in the absence of RC or CP.

[0090] Figure 5An example of an electrode arrangement having a stimulating electrode set and a recording electrode set is shown by way of example, not limitation. The electrode arrangement 525 can be located on a paddle lead or a percutaneous lead. The electrode arrangement can be close to the spinal cord implant and can have a length generally in the rostral-caudal direction of the patient and a width generally in the mediolateral direction of the patient. The electrode arrangement includes multiple electrode sets, including at least a first electrode set 526 and a second electrode set 527, spaced apart in width corresponding to the mediolateral direction across the spinal cord. The first electrode set 526 can be used for positioning on the stimulating electrode arrangement, and the second electrode set 527 can be used for recording the response to stimulation using the first electrode set 526. The second electrode set 527 can be maximally spaced from the first electrode set 526 in the rostral-caudal direction to increase the resolution for detecting the relative angle between the electrode arrangement and the spine. However, other embodiments may use a second electrode set 527 closer to the first electrode set 526. Furthermore, some embodiments may use additional electrode sets (e.g., a third set 528 and a fourth set 529) to record responses to stimuli using the first electrode set. These additional recording electrode sets can be used to construct plots in a cephalocoaxial direction. These plots can be compared with each other, which can be used to determine whether the SCS leads are truly anteroposteriorly oriented and parallel to the spinal cord.

[0091] Figure 6 Method 630 illustrates, rather than limits, a method for identifying the midline using responses to a range of locations stimulated. Figure 5The method is implemented using an electrode arrangement. As shown at 631, the neurostimulator can be configured to stimulate a series of locations of the patient using a subset of a first electrode set. Each subset can correspond to a stimulation location. Each subset can include at least two electrodes to provide at least one stimulating electrode and at least one returning electrode to stimulate each location. For each stimulated location in the series of stimulated locations, method 630 can include identifying a corresponding response measure for each subset within a second electrode set 631. For example, the series of stimulated locations using the first electrode set can include at least a first location and a second location. The second electrode set can include at least a first electrode and a second electrode. When the first location is stimulated, the corresponding response measure can include a first first location response measure for the first electrode and a second first location response measure for the second electrode. When the second location is stimulated, the corresponding response measure can include a first second location response measure for the first electrode and a second second location response measure for the second electrode. At 633, the system can be configured to identify the physiological midline based on the corresponding response measure for each stimulated location in the series of stimulated locations. The first and second "first position" response measures can be recorded or measured simultaneously, or at different times. The first and second "second position" response measures can also be recorded or measured simultaneously, or at different times.

[0092] Figure 7 Examples, rather than limitations, are shown in a way that demonstrates what can be used as stimulation electrodes (e.g.) Figure 5 The first set 526 in the middle) or the recording electrode (e.g., Figure 5 The second set (527) of electrodes is an exclusive subset. For example, a subset of stimulating electrodes may include at least one stimulating electrode and at least one returning electrode to stimulate each location. Each subset may include a single electrode (e.g., monopolar stimulation or monopolar sensing). Each subset may include at least two electrodes. Similarly, a subset of sensing electrodes may include differential pairs. If a subset is exclusive, an electrode used in one subset is not used in another subset.

[0093] Figure 8 Examples, rather than limitations, are shown to be suitable for use with stimulation electrodes (e.g., Figure 5 The first set in the middle) or recording electrodes (e.g., Figure 6 The second set of electrodes is a non-exclusive subset. If a subset is non-exclusive, electrodes used in one subset can be used in another subset, as illustrated by the overlapping subsets. This can be used to provide more stimulation and / or sensing locations across the width of the electrode array in the inward and outward directions.

[0094] Figure 9The recording of responses using a second electrode set 927 is illustrated by way of example, not limitation, when a series of locations are stimulated using a subset of the first electrode set 926. A series of locations can be stimulated using subset 1, then subset 2, and then subset 3 of the first set 926, such that the sequence moves gradually medially and laterally across the spinal cord. However, locations can be stimulated using subsets of other orders (e.g., subset 2, then subset 1, then subset 3). Each stimulated location can produce a response, which is recorded at sensing subsets 1, 2, and 3. Recording can be performed simultaneously or at different times. When a location is stimulated at subset 1, a first “first location” response measure 928A can be recorded at sensing subset 1, a second “first location” response measure 928B can be recorded at sensing subset 2, and a third “first location” response measure 928C can be recorded at sensing subset 3. Similarly, when the stimulus is located at subset 2, a first "second position" response measure 929A can be recorded at sensing subset 1, a second "second position" response measure 929B can be recorded at sensing subset 2, and a third "second position" response measure 929C can be recorded at sensing subset 3. When the stimulus is located at subset 3, a first "third position" response measure 930A can be recorded at sensing subset 1, a second "third position" response measure 931B can be recorded at sensing subset 2, and a third "third position" response measure 931C can be recorded at sensing subset 3. It should be noted that the number of subsets used for stimulation and the number of subsets used for sensing can be different, and it should also be noted that the number of subsets used for stimulation can be different from the number of subsets used for sensing.

[0095] ECAP features for each sensing point can be used to generate curves. Inner and outer trends can be used to infer lead position. Trend plotting across rows or along individual columns can be used to infer lead alignment relative to the spinal cord.

[0096] Figure 10 A paddle-type lead is illustrated by way of example, not limitation, which shifts a target bipolar inwards and outwards while simultaneously recording from other contacts. Electrodes used to provide stimulation can be considered a first electrode set 1026, and bipolars 1028 formed in each column can be referred to as subsets of the first electrode set. Electrodes used to provide recording can be referred to as a second electrode set 1027. The target bipolar can be shifted to move the target poles inwards and outwards while simultaneously recording from associated contact pairs on the paddle. Recordings can be plotted relative to the inward and outward positions to establish a relative relationship. As stimulation moves, each of these subsets of recording electrodes (e.g., a monopolar electrode or a differential pair) can receive an ECAP signal or a signal scaled according to the amount of activation of the dorsal column fibers.

[0097] A profile can be developed from the recording to indicate the proximity to the midline and the position of the cathode. For example, when the cathode is centered on the midline, the two middle contacts may sense a larger signal, while the lateral contacts may sense a smaller signal, and these signals may progress symmetrically. Models, estimates from previous studies, or anatomical knowledge can be used to construct the expected profile, based on the cathode's position and the expected distance to or from the midline. The actual recorded profile can be compared to the predicted profile. For example, the predicted profile can be created at the initial lead placement or based on the assumption that we are exactly on the midline. ECAP features that can be used, by way of example rather than limitation, include amplitude, area under the curve (AUC), curve length, power spectrum characteristics, small wave characteristics, correlation with the template, and progression with known stimulus parameters (e.g., amplitude, PW).

[0098] Figure 11 A paddle-type lead is illustrated by way of example, not limitation, which shifts inner and outer shielded triodes while recording from other contacts. Instead of using target bipolars to stimulate these sites, inner and outer shielded triodes or cathode monopolars are used to attempt to provide more concentrated stimulation, selectively engaging specific groups of back-pillar fibers. The electrodes used to provide stimulation can be considered a first electrode set 1126, and the triodes 1129 formed in each column can be referred to as a subset of the first electrode set. The triodes can be compressed into bipolars near the edges of the electrode arrangement. The profiles for bipolars and tripolars may differ in some respects, and these differences can be determined using multiple target poles. The electrodes used to provide recording can be referred to as a second electrode set 1127.

[0099] Figure 12A paddle-shaped lead is illustrated by way of example, not limitation, constructing plots in the anteroposterior direction. These plots can be compared with each other, which can be used to determine whether the SCS lead is truly anteroposteriorly oriented and parallel to the spinal cord. For example, three, four, or five rows can be used for recording instead of recording on a single row. The electrodes used to provide stimulation can be considered as the first electrode set 1226. The electrodes used to provide recording can be referred to as the second electrode set 1227, the third electrode set 1228, and the fourth electrode set 1229. Not only is anteroposterior orientation evaluated, but the system can also evaluate how left-to-right orientation changes up and down the lead. Thus, a maximum value may indicate the midline position, but the midline may sway or shift to the left or right when you move the lead up or down, for example, if the lead bends. If the lead is indeed parallel to the dorsal column, the system can be configured to determine whether the trend for the contact and / or the trend along each row (when compared between rows) is consistent with the predicted signal. In addition to the ECAP features identified above, when using multiple recording electrode sets, delays between different sensing channels can also be used.

[0100] Figure 13 The measurement of medial and lateral biomarkers is illustrated by way of example, not limitation. An example of a programmer's programming screen 1330 is shown. Medical imaging can be used to provide images. The figure shows an electrode arrangement 1325 on a spinal anatomy. Four recording sites ("1", "2", "3", and "4") are shown in the figure. Furthermore, medial and lateral stimulation sweeps can be performed along the top (cephalic end) of the electrode arrangement 1325 while recording simultaneously at each of the recording sites. The sweeps can generate recordings as a function of the medial and lateral (recording) locations, which can be used to track the recursion of the recorded biomarkers relative to the recording locations. Example recordings at each of these sites are shown at 1331, and ECAP amplitudes (e.g., N1-P2) can be plotted for each of these medial and lateral recording sites as shown at 1332. The highest amplitude is at the second site, which infers that the midline is closer to the second site. Figure 13 The plot shows the "true profile". Instead of plotting N1-P2 against the ML position of the recording electrodes, curves can be generated for stimulation sites (e.g., more than four stimulation sites), as shown in the figure. Figure 15 As shown.

[0101] Figure 14Physiological midline identification and recommendations are illustrated by way of example, not limitation. A characteristic relationship should exist between biomarkers and medial / lateral locations. This relationship is expected to be roughly symmetrical about the physiological midline, with biomarkers (at the direct caudal contact) maximally located where the distal cerebrospinal fluid (dCSF) is thinnest and where the most activated DC fibers are found. Locations where the degree of “imbalance” and / or the trend of signal intensity reverses relative to medial / lateral locations can be used as a means of detecting and recommending midline and / or thus shift programming.

[0102] The "expected" ratio can be based on user-defined placement and image registration, etc. A "mismatch" between the model contour (based on the initial placement on the programming screen and the measured contour) can be used to "adjust" or suggest adjustments to the lead position on the programming screen. During periodic calibration checks / if the patient experiences unwanted changes, contour shape can be monitored and / or maintained within a certain range. The direction of displacement corresponds to the direction of the detected imbalance / contour change.

[0103] The system can display a comparison between the actual contour 1433 and the hypothetical position 1434. The hypothetical position 1434 can be exactly in the middle of the spinal cord, thus generating curve 1435. The actual contour 1433 is generated based on actual recordings. These contours can be compared. The system can preload a contour library and compare the actual contour 1433 with the library to find the best match, thus finding the actual placement 1436. The device can then quickly switch to the correct contour or the contour that best matches the actual contour. Therefore, if the paddle is displaced, the system may attempt to find the actual paddle placement that best suits the actual contour.

[0104] Figure 15 The characteristic variations based on medial and lateral displacement from the midline are illustrated by way of example, not limitation. The figure shows a paddle-shaped lead with a set of stimulating electrodes and a set of recording electrodes, and further illustrates a plotting of the average characteristic range across all locations relative to the medial and lateral bipolar displacement from the midline (e.g., in millimeters). Sweeping stimulation medially and laterally relative to the physiological midline of the system causes a change in the average amplitude of evoked potentials sensed by a series of monopoles throughout the space. Traces can be derived (e.g., plotted) by always recording at a fixed contact, recording at a contact depending on which contact is used for stimulation, or averaging traces from multiple contacts together. The amplitude or intensity required to produce a given magnitude of evoked neural response at a given contact can also be plotted relative to the medial and lateral stimulation locations.

[0105] Figure 16The characteristic response to right-side medial-lateral paddle displacement is illustrated by way of example, not limitation. The midline is shown to the right of the paddle lead shown. When the modeled physiological midline deviates from its central location and a 3mA stimulus is moved in the medial-lateral direction, the mean evoked potential characteristic range (as sensed and plotted by the paddle lead) skews towards the midline. Since the biomarker is expected to be maximum when most dorsal columns are activated, the “skew” indicates an imbalance regarding the midline orientation towards “row” 4. This effect also scales with amplitude as the effect becomes more pronounced with increasing stimulus delivery. Measurements can be repeated for the stimulus at different amplitudes to more definitively infer the midline.

[0106] Figure 17 The characteristic response to a correctly positioned paddle is illustrated by way of example rather than limitation. As shown in the plot, small changes were detected when the physiological midline was at or near the center of the lead, and when a 3mA bipolar stimulation was applied across the paddle lead for a sweep. Since the biomarker is expected to be maximum when most dorsal columns are activated, the symmetry suggests that the midline is located between the intermediate dorsal columns, as the contact point is closest to the midline.

[0107] Figure 18 The characteristic response to left-side medial-lateral paddle displacement is illustrated by way of example, not limitation. The midline is shown to the left of the paddle lead shown. When the physiological midline is deviated from its central location and a 3mA stimulus is moved medially and laterally, the mean evoked potential characteristic range (as sensed by the paddle lead) skews toward the midline. Since the biomarker is expected to be maximum when most dorsal columns are activated, the term "deviation" indicates an imbalance regarding the midline's orientation toward the first column.

[0108] Figure 19 The effect of increasing the amplitude of the evoked stimulus is illustrated by example rather than as a limitation. The plot provides representations of 1.0 mA, 2.5 mA, and 7.0 mA stimuli. This effect is first detectable at around 2.5 mA and becomes more pronounced at higher stimulus amplitudes. The consistency of the trend with changes in amplitude (e.g., increasing amplitude) can be used as a confirmatory indicator for identifying the midline.

[0109] Figure 20 Stimulus configurations are illustrated by way of example rather than limitation. In this non-limiting example for modeling the response, the inner and outer stimulation sweeps can move from the left bipolar to the left tripolar, then to the extended tripolar, to the right tripolar, and finally to the right bipolar. As indicated above, the stimulus can be swept gradually from one side of the electrode arrangement to the other. Alternatively, the stimulus may not be swept across, but rather directed to the stimulus location in a different order, such as, but not limited to, the extended tripolar, left bipolar, left tripolar, right bipolar, and right tripolar.

[0110] Figure 21 The displacement of the right lead midline in response to a 3mA stimulus and the average differential sensing at two levels are illustrated by way of example, not limitation. The right bipolar provides the maximum signal. Due to the different geometry, the profile will also differ. The actual way the electrodes use tripolar activated back posts will differ from the way they use bipolar activated back posts. However, it will still generate characteristics or unique profiles that can be used to infer lead placement.

[0111] Figure 22 The midline displacement of the paddle centering induced in response to a 3mA stimulus and the average differential sensing at two levels are illustrated by way of example, not limitation. These plots are relatively symmetrical between the left and right bipolar poles and between the left and right tripolar poles, and can be used to infer lead placement.

[0112] Figure 23 The midline displacement of the right lead induced by a 3mA stimulus and the average differential sensing at two levels are illustrated by way of example, not limitation. The left bipolar displacement is the largest, greater than the right bipolar displacement, and the left tripolar displacement is the largest, greater than the right tripolar displacement. This can be used to infer lead placement. Therefore, as... Figures 21-23 As shown, the response to different geometries can also serve as a “profile” indicating the placement of the lead wire.

[0113] Figure 24 The stimulation of a paddle-shaped lead rotation is illustrated by way of example, not limitation. A spinal cord lookup table corresponds to measurement grid points, which are associated with contact positions and medial / lateral displacements. The diagram shows the rotation point around the stimulating electrode (e.g., the cathode). The sensing anode and cathode can be moved independently. The axis can be rotated around the rotation point from -3 degrees to 3 degrees. The directions of medial / lateral displacement are indicated by arrows. The medial / lateral positions of the rotation point can be swept across.

[0114] Figure 25 Interpolation of sensing contacts based on nearest grid points is illustrated by way of example, not limitation. The predicted position can be based on the mapped rotational position. Interpolation (e.g., element-wise bilinear interpolation) can be performed on known grid points to estimate the points between grid points. Some embodiments determine the degree of rotation of the electrode arrangement based on the shape of the recorded action potential or on a recursive basis of the set action potential along the lead, such as... Figures 26-27 As shown.

[0115] Figure 26 The plot is shown by way of example rather than limitation, illustrating how three pairs of contacts on the same paddle lead can be used to detect rotation of the paddle lead along the inner-outer-tail path. Figure 27 The rotation angles of the paddle-shaped lead relative to the centerline are shown by way of example rather than limitation (e.g., 0 degrees from the centerline, +3 degrees from the centerline, -3 degrees from the centerline), and the construction is further identified. Figure 26 The plots are derived from the recording electrode differential pairs. The paddles shown are simplified versions of the actual leads to illustrate the determination of rotation. The dimensions of the modeled leads include 0.5 mm spacing (center-to-center between columns), 6.6 mm spacing (center-to-center between rows), and sensing using the bottom two rows of contacts, with stimulation and sensing occurring from the left contact column, the middle contact column, and the right contact column. It should be noted that the electrode dimensions may vary in different columns. The system can be designed with a library of entries specific to the paddles used. These figures show that if you rotate the leads, you can detect rotation as the contacts rotate closer to the centerline, making the ECAP larger. As rotation increases, the displacement and asymmetry between the lateral differential pairs relative to the middle differential pair become more pronounced. Stimulation can be delivered on a set of contacts initially assumed to be “centerline” or “symmetrical.” As a calibration check, the stimulation can be periodically swept inside and outside to assess symmetry. The steering and lead placement can be adjusted to account for this rotation / displacement.

[0116] Preliminary modeling results suggest that the relationship between evoked neural response characteristics and medial / lateral location can be used as a method for detecting the physiological midline, potentially simplifying programming. For example, the midline could be located without medical imaging, as some known software mirrors fluorescence microscope images to provide lead drag-and-drop functionality on the image. This information can be fed into algorithms / programs that determine the simulated parameters of the implanted lead, taking into account lead offset and relative lead movement during trial, post-permanent implantation, or surgery.

[0117] The above detailed description includes references to the accompanying drawings, which form part of the detailed description. The drawings illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as “examples.” Such examples may include elements other than those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Furthermore, the inventors also contemplate examples using combinations or arrangements of those elements shown or described.

[0118] The methods described herein may be implemented, at least in part, by a machine or computer. Some examples may include a computer-readable or machine-readable medium encoded with instructions operable to configure an electronic device to perform the methods described in the examples above. Implementations of this method may include code, such as microcode, assembly language code, high-level language code, or the like. This code may include computer-readable instructions for performing various methods. The code may form part of a computer program product. Furthermore, in the examples, the code may be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of such tangible computer-readable media may include, but are not limited to, hard disks, removable disks or magnetic tapes, removable optical discs (e.g., optical discs and digital video discs), memory cards or sticks, random access memories (RAM), read-only memories (ROM), and the like.

[0119] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used by those skilled in the art upon review of the above description. The scope of the invention should be determined by reference to the appended claims, together with the full scope of their legally claimed equivalents.

Claims

1. A system comprising: an electrode arrangement configured to be positioned proximate to a patient’s spinal column, wherein the electrode arrangement has a length generally in a cranial-caudal direction of the patient and a width generally in a medial-lateral direction of the patient, and the electrode arrangement includes a first set of electrodes spaced across the width and a second set of electrodes spaced across the width; a neurostimulator configured to be connected to the electrode arrangement, and further configured to: stimulate a series of locations of the patient using a subset of the first set of electrodes; for each stimulated location of the stimulated series of locations, identify a respective response measure for each subset of electrodes within the second set of electrodes, wherein the stimulated series of locations includes at least a first location and a second location, and the second set of electrodes includes at least a first subset of electrodes and a second subset of electrodes, for the first location, the respective response measure includes a first first-location response measure for the first subset of electrodes and a second first-location response measure for the second subset of electrodes, and for the second location, the respective response measure includes a first second-location response measure for the first subset of electrodes and a second second-location response measure for the second subset of electrodes, wherein the system is configured to identify a physiological midline based on the respective response measure for each stimulated location of the stimulated series of locations.

2. The system of claim 1, wherein the neurostimulator is configured to identify the physiological midline.

3. The system of claim 1, wherein the system includes a programmer configured to program the neurostimulator, and the programmer is configured to identify the physiological midline.

4. The system of claim 3, wherein the programmer is configured to program the neurostimulator using the identified physiological midline.

5. The system of any of claims 3-4, wherein the programmer is configured to compare changes in the respective response measures to detect relative movement between the spinal column and the electrode arrangement, and to reprogram the neurostimulator connected to the electrode arrangement based on the detected relative movement.

6. The system of any of claims 3-5, wherein the programmer includes a display, and is configured to provide a plot of the respective response measure for each stimulated location on the display, wherein the displayed plot is used to identify the physiological midline.

7. The system of any of claims 1-6, wherein the neurostimulator is configured to stimulate the series of locations by moving at least one pole used to deliver stimulation energy to stimulate the series of locations.

8. The system of claim 7, wherein the at least one pole includes a bipolar, the neurostimulator is configured to stimulate the series of locations by moving the bipolar used to deliver stimulation energy to stimulate the series of locations, and the bipolar includes a cathode and an anode.

9. The system of claim 7, wherein the at least one pole comprises a medial-lateral shielded tri-pole, the neurostimulator is configured to stimulate the series of locations by stimulating at least some of the locations using the medial-lateral shielded tri-pole, and the medial-lateral shielded tri-pole comprises a cathode generally between at least two anodes.

10. The system of claim 7, wherein the at least one pole comprises a monopole for stimulating at least some of the locations.

11. The system of claim 7, wherein the electrode arrangement comprises at least a third set of electrodes spaced across the width, wherein for each stimulated location in the series of stimulated locations, the neurostimulator is configured to: identify a respective response measure for each subset of electrodes within the third set of electrodes, wherein the system is configured to identify the physiological midline based on the respective response measures for each subset of electrodes within the second set of electrodes and the respective response measures for each subset of electrodes within the third set of electrodes; or form respective differential pairs for sensing using respective electrodes within the second set of electrodes and the third set of electrodes, and identify the respective response measures using the respective corresponding differential pairs.

12. The system of claim 11, wherein the programmer is configured to trend across rows of the second set of electrodes and the at least third set of electrodes to infer alignment of the lead with the physiological midline.

13. The system of claim 11, wherein the programmer is configured to trend along individual columns of electrodes in the second set of electrodes and at least the third set of electrodes.

14. The system of any of claims 1-13, wherein the electrode arrangement is on a paddle lead, and the electrode arrangement comprises at least three columns of electrodes.

15. The system of any one of claims 1-14, wherein, the respective response measures comprise a measure of at least one characteristic of an evoked compound action potential (ECAP), the characteristic selected from amplitude, area under the curve (AUC), curve length (CL), power spectral properties, wavelet properties, correlation with a template, recursion with known parameters, or at least one latency between different channels.

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