A multi-electrode dynamic sequence control system for DRG electrical stimulation

Abstract

This application discloses a multi-electrode dynamic sequence control system for DRG electrical stimulation. The system includes: M electrodes, each used to electrically stimulate M different DRGs; and an implantable pulse generator electrically connected to each of the M electrodes. The implantable pulse generator is configured to: after the current electrode completes electrical stimulation, acquire spatial distance information between the current electrode and each unstimulated electrode; generate distance priority values ​​for each unstimulated electrode based on the spatial distance information; dynamically determine at least one unstimulated electrode with the largest distance priority value to form a candidate electrode set; and select an electrode from the candidate electrode set as the electrode for the next electrical stimulation, prioritizing the stimulation of electrodes spatially farther from the current electrode. This application can effectively reduce the degree of mutual interference between multiple electrodes due to overlapping spatial electric fields in multi-DRG electrical stimulation and has significant real-time adaptive advantages.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a multi-electrode dynamic sequence control system for DRG electrical stimulation. Background Technology

[0002] Dorsal root ganglion (DRG) electrical stimulation is a neuromodulation technique that has been increasingly applied in the treatment of chronic pain and other diseases in recent years. By placing electrodes (also called "stimulation electrodes") near the dorsal root ganglion and applying stimulation signals, the transmission of pain signals can be modulated, thereby achieving a therapeutic effect of pain relief. Due to the relatively fixed anatomical position and sensitive response to stimulation of the dorsal root ganglion, DRG electrical stimulation shows promising clinical application prospects for specific indications.

[0003] However, in actual clinical practice, many patients with chronic pain (such as those with complex regional pain syndrome, polyneuropathy, or failed back surgery syndrome) often exhibit multi-segmental and widespread pain distribution. To achieve comprehensive and effective pain coverage, physicians typically need to implant multiple electrodes in different spinal cord segments to simultaneously perform multi-point neuromodulation targeting multiple different DRGs (i.e., multiple targets).

[0004] When an implantable pulse generator drives the electrodes to output stimulation signals, a specific spatial electric field distribution is formed in the conductive tissues surrounding the electrode contacts (such as cerebrospinal fluid, epidural fat, and tissues surrounding nerve roots). Traditional control strategies for driving multiple electrodes typically employ a fixed anatomical sequence (e.g., discharging sequentially from top to bottom along the spine) or a random polling sequence. However, because human tissue is an excellent conductive medium, there is a time delay in the dissipation of stimulation signals within the tissue. When two electrodes that are spatially close discharge consecutively within a very short time interval, the residual electric field generated by the first electrode has not yet completely dissipated before the new electric field generated by the second electrode is superimposed.

[0005] This overlap and coupling of spatial electric fields can cause serious interference problems between multiple electrodes. Specifically: on the one hand, the abnormal superposition and amplification of local spatial electric fields may lead to overactivation of target nerves and even non-target nerves (such as ventral motor nerve roots), causing patients to experience tingling sensations, unexpected paresthesia, or severe muscle spasms, posing a great safety hazard; on the other hand, the disordered interweaving of electric fields may also lead to distortion of charge distribution or mutual cancellation, destroying the original analgesic mechanism and causing a significant reduction in the overall therapeutic effect.

[0006] In summary, in multi-DRG electrical stimulation therapy, how to plan the working sequence of multiple electrodes to effectively avoid or reduce the mutual interference caused by the superposition of spatial electric fields between multiple electrodes, thereby ensuring the accuracy of analgesic effect and patient safety, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] This application provides a multi-electrode dynamic sequence control system for DRG electrical stimulation, which helps to solve the problem of mutual interference between multiple electrodes caused by the superposition of spatial electric fields in the prior art.

[0008] In a first aspect, embodiments of this application provide a multi-electrode dynamic sequence control system for DRG electrical stimulation, comprising: M electrodes, wherein the M electrodes are respectively used to electrically stimulate M different DRGs, wherein M is an integer greater than 1; and an implantable pulse generator, wherein the implantable pulse generator is electrically connected to the M electrodes respectively. The implantable pulse generator is configured to: after the current electrode completes electrical stimulation, acquire spatial distance information between the current electrode and each of the unstimulated electrodes; based on the spatial distance information, generate a distance priority value for each unstimulated electrode to characterize the priority of electrical stimulation, wherein the larger the spatial distance, the higher the corresponding distance priority value; dynamically determine at least one unstimulated electrode with the largest distance priority value to form a candidate electrode set; select an electrode from the candidate electrode set as the electrode for the next electrical stimulation, so as to prioritize the control of the electrode that is spatially farther from the current electrode for electrical stimulation; wherein the unstimulated electrodes are the electrodes that have not yet performed electrical stimulation in the current stimulation cycle, and each electrode performs one electrical stimulation action in one stimulation cycle.

[0009] In one possible implementation, after the current electrode completes electrical stimulation, obtaining the spatial distance information between the current electrode and each of the unstimulated electrodes includes: obtaining the position information of the current electrode and each of the remaining unstimulated electrodes in the electrode distribution map; determining the spatial distance information between the current electrode and each of the remaining unstimulated electrodes based on the position information of the current electrode and each of the remaining unstimulated electrodes; wherein the electrode distribution map includes the position information of each of the electrodes.

[0010] In one possible implementation, the position information is coordinate information. Before obtaining the position information of the current electrode and the remaining unstimulated electrodes in the electrode distribution map, the method further includes: applying a first test signal between any two electrodes among the M electrodes; measuring the impedance between the arbitrary two electrodes; converting the measured impedance between the arbitrary two electrodes into spatial distance information between the arbitrary two electrodes based on a preset impedance-distance mapping relationship; using any one of the M electrodes as a spatial reference, performing three-dimensional spatial coordinate calculation based on all the spatial distance information to obtain the coordinate information of each electrode in three-dimensional space; generating an electrode distribution map based on the coordinate information of each electrode in three-dimensional space; wherein the amplitude of the first test signal is less than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the first test signal is less than the pulse width of the stimulation signal when the DRG is electrically stimulated.

[0011] In one possible implementation, the position information is coordinate information. Before obtaining the position information of the current electrode and the other unstimulated electrodes in the electrode distribution map, the method further includes: controlling a target electrode among the M electrodes to output a second test signal, wherein the target electrode is any one of the M electrodes; controlling the other electrodes besides the target electrode as monitoring electrodes to collect neurally evoked compound action potentials triggered by the second test signal; obtaining the time delay between the second test signal output by the target electrode and the neurally evoked compound action potentials collected by each of the monitoring electrodes; converting the measured time delay into spatial distance information between the target electrode and each of the monitoring electrodes based on a preset delay-distance mapping relationship; using the target electrode as a spatial reference, performing three-dimensional spatial coordinate calculations based on all the spatial distance information to obtain the coordinate information of each electrode in three-dimensional space; and generating an electrode distribution map based on the coordinate information of each electrode in three-dimensional space.

[0012] In one possible implementation, the position information is coordinate information. Before obtaining the position information of the current electrode and the other unstimulated electrodes in the electrode distribution map, the method further includes: receiving coordinate calibration data sent by an external programmable device through the implantable pulse generator, wherein the coordinate calibration data includes the coordinate information of the M electrodes in three-dimensional space extracted based on human medical images; and generating an electrode distribution map based on the coordinate information of each electrode in three-dimensional space.

[0013] In one possible implementation, the implantable pulse generator is further configured to update the electrode distribution map when a preset update condition is met; wherein the preset update condition includes at least one of the following: system initialization; reaching a preset update cycle; or detecting that the impedance change between any two electrodes exceeds a preset offset threshold.

[0014] In one possible implementation, acquiring the spatial distance information between the current electrode and each of the unstimulated electrodes after the current electrode completes electrical stimulation includes: applying a third test signal between the current electrode and each of the unstimulated electrodes after the current electrode completes electrical stimulation; measuring the impedance between the current electrode and each of the unstimulated electrodes; and converting the measured impedance between the current electrode and each of the unstimulated electrodes into spatial distance information between the current electrode and each of the unstimulated electrodes based on a preset impedance-distance mapping relationship; wherein the amplitude of the third test signal is less than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the third test signal is less than the pulse width of the stimulation signal when the DRG is electrically stimulated.

[0015] In one possible implementation, acquiring the spatial distance information between the current electrode and each of the unstimulated electrodes after the current electrode completes electrical stimulation includes: controlling the current electrode to output a fourth test signal after the current electrode completes electrical stimulation; controlling each of the unstimulated electrodes as monitoring electrodes to collect neurally evoked compound action potentials triggered by the fourth test signal; acquiring the time delay between the fourth test signal output by the current electrode and the neurally evoked compound action potentials collected by each of the monitoring electrodes; and converting the measured time delay into spatial distance information between the current electrode and each unstimulated electrode based on a preset delay-distance mapping relationship.

[0016] In one possible implementation, the implantable pulse generator is further configured to: at the start of one of the stimulation cycles, randomly select one electrode from the M electrodes as the first electrode to perform electrical stimulation.

[0017] In one possible implementation, the implantable pulse generator is further configured to reduce the amplitude and / or pulse width of the next electrical stimulation if the spatial distance between the current electrode and the electrode for the next electrical stimulation is less than or equal to a preset spatial distance threshold.

[0018] The technical solution of this application embodiment can effectively reduce the degree of mutual interference between multiple electrodes due to overlapping spatial electric fields in multi-DRG electrical stimulation. Since the electric field strength in human tissue attenuates with increasing physical distance, this control system, after each electrical stimulation, forcibly prioritizes the unstimulated electrode furthest from the current electrode for the next discharge. This mechanism establishes maximum physical spatial isolation between two consecutive stimulations, ensuring that the residual electric field of the preceding electrode has significantly attenuated by the time it spreads to the next working electrode. This reduces the cross-coupling of local electric fields and lowers the risk of unintended activation of non-target nerves (such as causing muscle spasms) or attenuation of analgesic effects.

[0019] Furthermore, the "dynamic sequence control" of this scheme has a significant real-time adaptive advantage. In actual clinical practice, changes in patient position or daily activities can easily lead to relative displacement between the implanted electrodes. Before each stimulation, this control system performs real-time optimization based on the currently unstimulated electrodes and spatial distance information. This dynamic evolution mechanism can adapt to distance changes caused by physical displacement, improving resistance to environmental interference and contributing to long-term safe regulation under complex physiological conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural block diagram of a multi-electrode dynamic sequence control system for DRG electrical stimulation provided in an embodiment of this application. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0023] Dorsal root ganglion (DRG) electrical stimulation is a neuromodulation technique that has been increasingly applied in the treatment of chronic pain and other diseases in recent years. By placing electrodes (also called "stimulation electrodes") near the dorsal root ganglion and applying stimulation signals, the transmission of pain signals can be modulated, thereby achieving a therapeutic effect of pain relief. Due to the relatively fixed anatomical position and sensitive response to stimulation of the dorsal root ganglion, DRG electrical stimulation shows promising clinical application prospects for specific indications.

[0024] However, in actual clinical practice, many patients with chronic pain (such as those with complex regional pain syndrome, polyneuropathy, or failed back surgery syndrome) often exhibit multi-segmental and widespread pain distribution. To achieve comprehensive and effective pain coverage, physicians typically need to implant multiple electrodes in different spinal cord segments to simultaneously perform multi-point neuromodulation targeting multiple different DRGs (i.e., multiple targets).

[0025] When an implantable pulse generator drives the electrodes to output stimulation signals, a specific spatial electric field distribution is formed in the conductive tissues surrounding the electrode contacts (such as cerebrospinal fluid, epidural fat, and tissues surrounding nerve roots). Traditional control strategies for driving multiple electrodes typically employ a fixed anatomical sequence (e.g., discharging sequentially from top to bottom along the spine) or a random polling sequence. However, because human tissue is an excellent conductive medium, there is a time delay in the dissipation of stimulation signals within the tissue. When two electrodes that are spatially close discharge consecutively within a very short time interval, the residual electric field generated by the first electrode has not yet completely dissipated before the new electric field generated by the second electrode is superimposed.

[0026] This overlap and coupling of spatial electric fields can cause serious interference problems between multiple electrodes. Specifically: on the one hand, the abnormal superposition and amplification of local spatial electric fields may lead to overactivation of target nerves and even non-target nerves (such as ventral motor nerve roots), causing patients to experience tingling sensations, unexpected paresthesia, or severe muscle spasms, posing a great safety hazard; on the other hand, the disordered interweaving of electric fields may also lead to distortion of charge distribution or mutual cancellation, destroying the original analgesic mechanism and causing a significant reduction in the overall therapeutic effect.

[0027] In summary, in multi-DRG electrical stimulation therapy, how to plan the working sequence of multiple electrodes to effectively avoid or reduce the mutual interference caused by the superposition of spatial electric fields between multiple electrodes, thereby ensuring the accuracy of analgesic effect and patient safety, is a technical problem that urgently needs to be solved by those skilled in the art.

[0028] To address the aforementioned issues, this application provides a multi-electrode dynamic sequence control system for DRG electrical stimulation. This system effectively reduces the mutual interference between multiple electrodes due to overlapping spatial electric fields during multiple DRG electrical stimulation, and offers significant real-time adaptive advantages through "dynamic sequence control." The specific implementation will be described in detail below.

[0029] See Figure 1 This is a structural block diagram of a multi-electrode dynamic sequence control system for DRG electrical stimulation provided in an embodiment of this application. Figure 1 As shown, the control system includes M electrodes, each used to electrically stimulate M different DRGs, where M is an integer greater than 1; and an implantable pulse generator, which is electrically connected to each of the M electrodes.

[0030] In this embodiment, to more clearly describe the operating logic of the control system, the electrodes and spatial distance information are first explained. Typically, an electrode physically includes an electrode wire and electrode contacts located at the ends (distal ends) of the electrode wire. The spatial distance information acquired by the implanted pulse generator usually refers to the spatial distance between the electrode contacts of each electrode. Since the electrode contacts are the physical interfaces through which the electrical stimulation signal is actually released and comes into contact with human tissue, using them as the basis for distance calculation can more accurately reflect the distribution of the spatial electric field.

[0031] In practice, the control system operates on a cycle basis. Within a stimulation cycle, each electrode performs one electrical stimulation action. Electrodes that are not electrically stimulated within this cycle are those that have not yet received electrical stimulation in the current stimulation cycle.

[0032] To determine the order of stimulation, after the current electrode completes electrical stimulation, the implantable pulse generator acquires the spatial distance information between the current electrode and each of the unstimulated electrodes. Based on this distance data, the implantable pulse generator generates a distance priority value for each unstimulated electrode, characterizing the priority of electrical stimulation. The system follows the following mapping logic when generating this distance priority value: the larger the spatial distance, the higher the corresponding distance priority value.

[0033] Furthermore, the implantable pulse generator dynamically determines at least one unstimulated electrode with the largest distance priority value to form a candidate electrode set, and selects one electrode from the candidate electrode set as the electrode for the next electrical stimulation, so as to prioritize the electrical stimulation of the electrode that is spatially farther away from the current electrode.

[0034] Understandably, due to the conductivity of human tissue and internal fluid environment, electrode contacts generate a specific spatial electric field around them when outputting stimulation signals. If two electrodes with relatively close physical locations discharge consecutively on the time axis, the dissipation of the preceding electric field requires a certain amount of time, and the appearance of the subsequent electric field may cause local spatial electric fields to overlap and couple. This application incorporates spatial dimension considerations into the control logic, prioritizing the electrode that is farther away as the next electrical stimulation target, thereby actively introducing maximum physical spatial isolation between two consecutive electrical stimulation actions. This spatial isolation mechanism allows the residual electric field generated by the preceding electrode to be significantly attenuated by the time it diffuses to the next working electrode, thereby reducing the cross-coupling of local electric fields and reducing the risk of non-target nerves being mistakenly activated (such as causing muscle spasms) or the analgesic effect being reduced.

[0035] Furthermore, the "dynamic sequence control" of this scheme has a significant real-time adaptive advantage. In actual clinical practice, changes in patient position or daily activities can easily lead to relative displacement between the implanted electrodes. Before each stimulation, this control system performs real-time optimization based on the currently unstimulated electrodes and spatial distance information. This dynamic evolution mechanism can adapt to distance changes caused by physical displacement, improving resistance to environmental interference and contributing to long-term safe regulation under complex physiological conditions.

[0036] Furthermore, in the embodiments of this application, the "at least one unstimulated electrode with the largest distance priority value" can include different configurations in specific cases: In one scenario, when there is only one "at least one with the largest distance priority value", the implantable pulse generator extracts only the unstimulated electrode with the highest distance priority value (i.e., the largest absolute spatial distance), forming a candidate electrode set. In this case, the implantable pulse generator selects one electrode from the candidate electrode set as the electrode for the next electrical stimulation, effectively directly identifying the farthest electrode as the next target.

[0037] In another scenario, when there are multiple "at least one with the largest distance priority value," it doesn't mean there are multiple electrodes with completely equal spatial distances. Instead, it refers to the top few electrodes ranked from largest to smallest distance priority value. For example, an implantable pulse generator can extract the three unstimulated electrodes with the top three distance priority values, forming a candidate electrode set. In scenarios where the candidate electrode set contains multiple electrodes, the implantable pulse generator can use a random selection algorithm to randomly select one electrode from this set as the electrode for the next electrical stimulation, prioritizing the stimulation of electrodes that are spatially farther from the current electrode.

[0038] This application's embodiment, by randomly selecting from multiple electrodes (i.e., electrodes ranked high in distance priority) within a candidate electrode set, introduces a moderate degree of spatial randomness into the temporal scheduling of the control system while ensuring the anti-crosstalk principle of "prioritizing control of more distant electrodes." In long-term neuromodulation therapy, if the system mechanically seeks the single, absolutely furthest target each time, it can easily form a rigid, cyclical stimulation path between a few fixed electrodes. Introducing a random selection mechanism for the top candidate electrodes allows for dynamic fine-tuning of the electrode triggering sequence within each stimulation cycle. To some extent, this may help reduce synaptic habituation (i.e., neural tolerance) of the nervous system to fixed electrical stimulation paths, thereby maintaining a more stable analgesic effect in long-term chronic pain intervention.

[0039] In one possible implementation, after the current electrode completes electrical stimulation, spatial distance information between the current electrode and each of the unstimulated electrodes is obtained, including: obtaining position information of the current electrode and each of the other unstimulated electrodes in the electrode distribution map; and determining the spatial distance information between the current electrode and each of the other unstimulated electrodes based on the position information of the current electrode and each of the other unstimulated electrodes.

[0040] In practice, the electrode distribution map includes the positional information of each electrode. At the physical level, this positional information typically refers to the coordinate data of the electrode contacts within the human anatomical structure or the device's three-dimensional coordinate system. The electrode distribution map can be understood as a spatial topology mapping table stored in the memory of the implantable pulse generator, recording the relative positional relationships of all electrode contacts in three-dimensional space.

[0041] Specifically, the process by which an implanted pulse generator acquires spatial distance information includes: First, the position information of the current electrode and all other electrodes that have not yet been electrically stimulated is obtained from the electrode distribution map. That is, the implantable pulse generator retrieves the coordinate data of the electrode contact that has just completed an electrical stimulation action, as well as the coordinate data of all other electrode contacts that have not yet undergone electrical stimulation action, from the aforementioned mapping table.

[0042] Then, based on the position information of the current electrode and the other unstimulated electrodes, the spatial distance information between the current electrode and each of the unstimulated electrodes is determined. In specific implementation, the implantable pulse generator can use its internal processor and spatial geometry algorithm (such as the Euclidean distance formula) to directly calculate the straight-line distance between each pair of the current electrode and each of the unstimulated electrodes based on the extracted coordinate data.

[0043] Understandably, in practical applications, it's possible to measure and calculate the spatial distance between electrodes in real time by temporarily transmitting test signals after each electrical stimulation (e.g., transmitting weak impedance probe currents or neural evoked potential probe pulses). However, the transmission, conduction, reception, sampling, and subsequent analog-to-digital conversion and analysis of the test signals all consume physical time. This means that if real-time detection is used, this detection time will forcibly occupy the time interval between two regular stimulation signals, passively lengthening the time interval between adjacent stimulations. In multi-DRG electrical stimulation, the frequency of the stimulation signal is one of the core parameters determining the analgesic effect. A prolonged interval between two stimulations leads to a decrease in the overall stimulation frequency, which in turn weakens or even affects the original therapeutic effect to some extent.

[0044] In contrast, the embodiments of this application determine spatial distance by directly reading the positional information in the electrode distribution map and performing mathematical calculations. The calculation process can usually be completed in a short time, hardly occupying the physical time interval between two electrical stimulations. This approach avoids the reduction in stimulation frequency caused by the time spent on distance measurement, thereby ensuring the analgesic therapeutic effect during continuous multi-electrode stimulation to a certain extent.

[0045] Furthermore, by not relying on real-time transmission of test signals, this approach avoids, to some extent, the high power consumption issues caused by high-frequency physical detection, thus helping to extend the battery life of the implantable pulse generator and reducing the possibility of introducing additional electromagnetic noise interference into neural tissue. Therefore, this solution is particularly suitable for applications requiring high stimulation frequency, low power consumption, and low noise interference.

[0046] In this embodiment, the position information of the electrodes can be specifically represented as coordinate information in three-dimensional space. To successfully obtain position information from the electrode distribution map for subsequent dynamic timing control, the implanted pulse generator needs to first construct and store the electrode distribution map. Specifically, this embodiment provides various implementation schemes for generating electrode distribution maps.

[0047] In one possible implementation, the implantable pulse generator can generate an electrode distribution map based on the impedance characteristics of human tissue. Specifically, the implantable pulse generator applies a first test signal between any two electrodes out of M electrodes and measures the impedance between those two electrodes. Since the tissues of the epidural space (such as fat, cerebrospinal fluid, etc.) have specific resistivity, the equivalent impedance of an electrical signal propagating through the tissue is usually strongly correlated with the physical conduction distance. Therefore, the system can convert the measured impedance between any two electrodes into spatial distance information between them based on a preset impedance-distance mapping relationship. After obtaining the spatial distances between each pair of electrodes within the system, the implantable pulse generator uses any one of the M electrodes as a spatial reference (e.g., set as the origin of the coordinate system) and performs three-dimensional spatial coordinate calculations based on all the spatial distance information to obtain the coordinate information of each electrode in three-dimensional space. Finally, based on the coordinate information of each electrode in three-dimensional space, an electrode distribution map is generated and saved.

[0048] Furthermore, to ensure patient safety and comfort, the amplitude of the first test signal is smaller than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the first test signal is smaller than the pulse width of the stimulation signal when the DRG is electrically stimulated. This parameter setting ensures that the first test signal is typically in a subthreshold state of neural activation.

[0049] In this embodiment, the implantable pulse generator can independently and autonomously perform spatial coordinate self-calibration within the patient's body, reducing reliance on external large-scale surveying equipment. Simultaneously, employing a subthreshold first test signal with smaller amplitude or pulse width avoids accidental neural depolarization during the detection and ranging phase, reducing the likelihood of unexpected paresthesia or muscle twitching in the patient and improving system safety.

[0050] In another possible implementation, the implantable pulse generator can generate an electrode distribution map based on the neurophysiological conduction characteristics. Specifically, the implantable pulse generator controls a target electrode (any one of the M electrodes) to output a second test signal. Simultaneously, the remaining electrodes (excluding the target electrode) are controlled as monitoring electrodes to collect evoked compound action potentials (ECAPs) triggered by the second test signal. An ECAP refers to the macroscopic electrophysiological response signal synchronously generated by a group of nerve fibers after effective electrical stimulation. Next, the implantable pulse generator acquires the time delay between the second test signal output by the target electrode and the ECAPs collected by each monitoring electrode. Since nerve conduction velocity is relatively stable under specific physiological conditions, the system can convert the measured time delay into spatial distance information between the target electrode and each monitoring electrode based on a preset delay-distance mapping relationship. Subsequently, using the target electrode as a spatial reference, three-dimensional spatial coordinates are calculated based on all spatial distance information to obtain the coordinate information of each electrode in three-dimensional space, and an electrode distribution map is generated based on this coordinate information.

[0051] In this embodiment, the distance is estimated by the time delay of action potential conduction; the system actually obtains the "physiological conduction distance" between electrodes along the neuroanatomical pathway. Compared to purely physical straight-line distance, this physiological distance can more realistically reflect the topological coupling relationship of the various nodes of the nervous system in response to electrical stimulation. The electrode distribution map generated using this data helps the system make anti-crosstalk decisions that are more in line with neurophysiological characteristics during subsequent dynamic sequence optimization.

[0052] In another possible implementation, the implantable pulse generator can also generate an electrode distribution map using an external medical system. Specifically, the implantable pulse generator receives coordinate calibration data from an external programmable device via its internal communication module. This coordinate calibration data contains the coordinate information of M electrodes in three-dimensional space extracted from human medical images (such as intraoperative X-ray fluoroscopy, CT scans, or MRI images). Upon receiving this data, the implantable pulse generator directly generates an electrode distribution map based on the coordinate information of each electrode in three-dimensional space.

[0053] In this embodiment, coordinate information is extracted directly from high-resolution medical images, which typically has high anatomical and physical accuracy and is less susceptible to interference from local tissue inflammation, fluctuations in body fluid impedance, or individual differences in nerve conduction velocity. Furthermore, the massive computational work involved in image recognition and coordinate calculation is primarily performed by external medical devices or the cloud, with the implant only needing to perform receiving and storage actions. This conserves the computational resources of the implantable pulse generator and conserves valuable battery power.

[0054] It should be noted that the three methods for generating electrode distribution maps described above are only possible implementations and are not limiting. In specific implementations, the system may use any one of the above methods individually or combine multiple methods. For example, during the initial implantation surgery, coordinates from external medical images may be used as the initial electrode distribution map, while during long-term operation after the patient's discharge, the electrode distribution map may be dynamically updated periodically using impedance measurement or neurophysiological conduction methods. This application embodiment does not impose specific limitations on this approach.

[0055] In this embodiment, based on the aforementioned construction of the electrode distribution map, considering that the epidural space or the area surrounding nerve roots is a dynamic physiological environment, the physical positions of the electrode contacts within the human body are not absolutely static. To maintain the accuracy of system scheduling, this application also provides a mechanism for dynamically maintaining and updating the electrode distribution map.

[0056] In one possible implementation, the implantable pulse generator is further configured to update the electrode distribution map when preset update conditions are met. Specifically, the preset update conditions include at least one of the following: system initialization; reaching a preset update cycle; or detecting an impedance change between any two electrodes exceeding a preset offset threshold.

[0057] In practice, the "system initialization" condition typically occurs after the implantable pulse generator is first powered on, after a system reset, or after a firmware upgrade. Triggering an update to the electrode distribution map at this stage provides the latest and most reliable spatial reference topology data for dynamic sequence scheduling throughout the entire operational lifecycle.

[0058] To address the condition of "reaching the preset update cycle," the implantable pulse generator can be configured with a long-term timer. When the system's continuous operation or standby time reaches the set time interval (e.g., several days or weeks), a reassessment and update of the electrode distribution map is automatically triggered. This periodic maintenance mechanism is primarily used to correct chronic electrode displacement caused by factors such as slow growth and encapsulation of human tissue and minute muscle traction.

[0059] Regarding the update condition of "detecting an impedance change between any two electrodes exceeding a preset offset threshold," in practice, the implantable pulse generator can monitor the loop impedance between the two electrodes in the background using a weak detection signal during breaks in routine electrical stimulation therapy. Because the impedance between two electrodes is highly correlated with their physical distance in a relatively stable bodily fluid environment, when a patient experiences a drastic change in position, an accidental fall, or strenuous exercise, causing sudden slippage or significant displacement of the electrodes, the corresponding loop impedance value will exhibit a significant jump. Once the calculated impedance change exceeds the preset offset threshold, the system can determine that the current electrode map is invalid, thereby immediately triggering an update of the electrode map. In practice, to reduce system data processing load and shorten update time, only the position information of the electrodes that have shifted in the electrode map (i.e., the electrodes whose impedance change exceeds the preset offset threshold) can be updated, rather than a global update of the electrode map.

[0060] In this embodiment, the core of the multi-electrode dynamic sequence anti-crosstalk control relies heavily on accurate and real-time spatial distance information. If the electrode distribution map remains unchanged for a long period during the treatment cycle, and the electrodes physically shift due to internal or external factors, the system will still use the old, erroneous spatial distance information to search for the so-called "farthest electrode." This may cause the system to continuously discharge between two electrodes that are actually very close together, thereby triggering severe superposition and mutual interference of local spatial electric fields again. This embodiment ensures, to a certain extent, that the spatial distance information upon which the implantable pulse generator relies always conforms to the actual anatomical physical state, maintaining long-term anti-crosstalk isolation and control safety.

[0061] It should be noted that the specific settings for the preset update conditions mentioned above are only one possible implementation method and are not limiting. In a specific implementation, the system may also combine other triggering mechanisms to update the electrode distribution map. For example, when the body feature sensor detects an unexpected change in the patient's posture, or when the radio frequency communication module receives a manual calibration command from an external terminal device, the electrode distribution map update process can also be initiated.

[0062] In this embodiment of the application, in addition to the aforementioned method of obtaining spatial distance information by reading a pre-constructed electrode distribution map, the system can also obtain spatial distance information between the current electrode and each unstimulated electrode by performing real-time physical detection during the stimulation interval, without relying on the electrode distribution map.

[0063] In one possible implementation, impedance detection is used. Specifically, after the current electrode completes electrical stimulation, spatial distance information between the current electrode and each unstimulated electrode is acquired. This includes: applying a third test signal between the current electrode and each unstimulated electrode after electrical stimulation; then measuring the impedance between the current electrode and each unstimulated electrode; and finally, based on a preset impedance-distance mapping relationship, converting the measured impedance between the current electrode and each unstimulated electrode into spatial distance information between the current electrode and each unstimulated electrode.

[0064] In practice, to ensure patient comfort and overall system safety during the detection process, the parameters of the third test signal are subject to specific constraints. Specifically, the amplitude of the third test signal is less than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the third test signal is less than the pulse width of the stimulation signal when the DRG is electrically stimulated. This parameter setting ensures that the third test signal is typically in a subthreshold state of neural activation.

[0065] It is understandable that human tissues (such as epidural fat, cerebrospinal fluid, and muscle) possess certain resistivity characteristics as conductive media. The greater the physical distance between electrodes, the greater the equivalent impedance of the circuit they form. By transmitting a third test signal in real time after each electrical stimulation to measure impedance, the system can capture the true physical distance between the electrodes within the current extremely short time window. To a certain extent, this real-time detection mechanism does not require the system to continuously maintain and update a large electrode distribution map in memory, and it can quickly respond to and handle transient electrode displacements caused by sudden patient movements (such as sneezing or violent bending). This approach is particularly suitable for applications requiring high stimulation accuracy.

[0066] In another possible implementation, the implantable pulse generator can also acquire distance in real time based on the neurophysiological conduction characteristics. Specifically, after the current electrode completes electrical stimulation, the spatial distance information between the current electrode and each unstimulated electrode is acquired, including: after the current electrode completes electrical stimulation, controlling the current electrode to output a fourth test signal; simultaneously, controlling each unstimulated electrode as a listening electrode to collect the neurally evoked compound action potentials triggered by the fourth test signal; then, acquiring the time delay between the fourth test signal output by the current electrode and the neurally evoked compound action potentials collected by each listening electrode; finally, based on a preset delay-distance mapping relationship, the measured time delay is converted into spatial distance information between the current electrode and each unstimulated electrode.

[0067] In practice, a neurally evoked compound action potential (PEP) refers to a macroscopic electrophysiological response signal that is synchronously generated and conducted along the nerve fiber pathway after a group of nerve fibers receives an effective intensity of electrical stimulation. Since the conduction velocity of an action potential in a specific neuroanatomical pathway is relatively stable, a longer conduction time (i.e., time delay) usually means a longer spatial distance traveled by the signal.

[0068] Compared to the purely physical straight-line distance, the distance calculated from the conduction time delay of neurally evoked compound action potentials is essentially the "physiologically effective distance" along which the electrical signal travels along the patient's actual neuroanatomical pathway. In the complex anatomical environment of the spinal cord and dorsal root ganglia, the heterogeneity of tissue structure may lead to a discrepancy between the physical straight-line distance and the actual electrophysiological coupling degree. This physiologically effective distance can, to some extent, more objectively reflect the true risk of electrophysiological crosstalk between different electrodes. Utilizing the spatial distance information derived from this time delay for subsequent dynamic sequence priority evaluation helps the system develop anti-crosstalk scheduling strategies that are more aligned with individual neurobiological characteristics, further improving the accuracy of multi-DRG modulation.

[0069] It should be noted that the above-mentioned methods of obtaining spatial distance information through real-time impedance measurement or real-time neural signal monitoring are only one possible implementation and are not limited thereto. In specific implementations, the implanted pulse generator may also combine the system's real-time power status and computing resource load to dynamically and automatically switch between the electrode distribution map query scheme and the above-mentioned real-time physical detection scheme, in order to achieve a balance between reducing system power consumption and improving measurement real-time performance.

[0070] In one possible implementation, the implantable pulse generator is also configured to randomly select one electrode from M electrodes as the first electrode to perform electrical stimulation at the start of a stimulation cycle.

[0071] In practice, as described above, each electrode performs one electrical stimulation action within a stimulation cycle. When a new stimulation cycle begins, all M electrodes are initially idle and have not yet undergone electrical stimulation. At this time, the implantable pulse generator can randomly select one electrode from these M electrodes using an internally configured random number generator or pseudo-random algorithm, without any physical distance weighting preference. This selected electrode is then activated and becomes the first electrode to output an electrical stimulation signal within that stimulation cycle. Once this first electrode completes its discharge, the system immediately enters the aforementioned dynamic scheduling process based on spatial distance information to continuously search for the next electrode for electrical stimulation until all electrodes within that cycle have completed their discharge.

[0072] Understandably, although the aforementioned distance-first optimization strategy can maximize the physical isolation between electrodes in a single cycle, if each stimulation cycle is fixed with the same electrode (e.g., the electrode at the top of the anatomical position) as the starting point, then under the condition that the physical distribution of electrodes is relatively static, the subsequent electrical stimulation sequence calculated by the system according to the distance maximization principle may fall into a rigid, completely repetitive fixed arrangement pattern between multiple cycles (e.g., in each cycle, it always mechanically cycles in the order of electrode A, electrode D, electrode C, and electrode B).

[0073] This application introduces a random initial factor into each round of dynamic spatial optimization by randomly selecting the first electrode at the start of a stimulation cycle. Because the starting point of the system scheduling is randomly changed, the entire electrical stimulation sequence trajectory, dynamically derived based on spatial distance constraints, is also rearranged, resulting in rich dynamic diversity in the spatial stimulation timing between stimulation cycles. In long-term neuromodulation therapy, this macroscopically changing spatial stimulation sequence can, to some extent, break the synaptic habituation of the nervous system to fixed electrical stimulation pathways. This helps to delay or reduce the nervous system's tolerance to stimulation signals, thereby maintaining a more stable and long-lasting analgesic effect in long-term chronic pain intervention. Simultaneously, the constantly changing timing also helps to avoid long-term, regular accumulation and interference from residual spatial electric fields in a single local area.

[0074] In one possible implementation, the implantable pulse generator is further configured to reduce the amplitude and / or pulse width of the next electrical stimulation if the spatial distance between the current electrode and the electrode for the next electrical stimulation is less than or equal to a preset spatial distance threshold.

[0075] In practice, a preset spatial distance threshold typically represents a physical isolation safety boundary benchmark. When the distance between two electrodes activated sequentially is lower than this benchmark, the probability of severe superposition and crosstalk between their respective spatial electric fields increases significantly. Amplitude and pulse width are the core stimulation parameters that determine the total energy output of a single pulse of the electrical stimulation signal. Reducing the amplitude and / or pulse width of the next electrical stimulation can be achieved by individually lowering the voltage or current amplitude of the stimulation signal, or by individually shortening the pulse duration, the latter reducing both amplitude and duration.

[0076] In this embodiment, although the system prioritizes the farthest electrode as the target for the next electrical stimulation in the preceding dynamic control logic, the number of electrodes that have not yet been stimulated gradually decreases as a stimulation cycle nears its end. In some scenarios, the remaining few selectable electrodes may all be physically close to the current electrode; or in scenarios where the anatomical structure of a specific nerve segment of the patient is limited and the density of multiple electrode implantations is high, even if the system selects the relatively "farthest" electrode in the current candidate set, the absolute spatial distance may still be less than the preset spatial distance threshold. In this case, the system will trigger the aforementioned parameter reduction logic.

[0077] When the system, due to a reduction in the number of unstimulated electrodes or anatomical limitations, has to select a physically close electrode for continuous stimulation, maintaining conventional stimulation parameters can lead to the superposition of residual electric fields from previous stimulations with newly generated high-intensity spatial electric fields. This can easily cause charge accumulation overload in local neural tissue, resulting in misactivation of motor nerves or causing intense tingling sensations in the patient. This application addresses this issue by actively reducing the amplitude and / or pulse width of the next electrical stimulation when the execution distance is less than or equal to a preset spatial distance threshold. Essentially, this dynamically compensates for insufficient physical spatial isolation by actively reducing the volumetric range of the subsequent spatial electric field. This compensation mechanism can, to some extent, weaken the superposition peak of local electric fields, ensuring that the overall electric field strength after coupling remains within a safe physiological tolerance range. This helps to further prevent the safety risks of multi-electrode electric field crosstalk in dense electrode array control and timing scheduling at the end of stimulation cycles, improving the system's robustness in complex and extreme topological environments.

[0078] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0079] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0080] The embodiments described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A multi-electrode dynamic sequence control system for DRG electrical stimulation, characterized by, include: M electrodes, each used to electrically stimulate M different DRGs, where M is an integer greater than 1; An implantable pulse generator, wherein the implantable pulse generator is electrically connected to the M electrodes respectively; The implantable pulse generator is configured as follows: After the current electrode completes electrical stimulation, obtain the spatial distance information between the current electrode and each electrode that has not been electrically stimulated; Based on the spatial distance information, a distance priority value is generated for each of the unstimulated electrodes to characterize the priority of electrical stimulation. The larger the spatial distance, the higher the corresponding distance priority value. Dynamically determine at least one unstimulated electrode with the largest distance priority value to form a candidate electrode set; Select one electrode from the candidate electrode set as the electrode for the next electrical stimulation, so as to give priority to the control of the electrode that is spatially farther away from the current electrode for electrical stimulation; The unstimulated electrodes are those that have not yet been electrically stimulated in the current stimulation cycle. In one stimulation cycle, each electrode performs an electrical stimulation action once.

2. The control system of claim 1, wherein, The step of acquiring spatial distance information between the current electrode and each unstimulated electrode after the current electrode has completed electrical stimulation includes: Obtain the position information of the current electrode and all other unstimulated electrodes from the electrode distribution map; Based on the position information of the current electrode and each of the other unstimulated electrodes, determine the spatial distance information between the current electrode and each of the unstimulated electrodes; The electrode distribution map includes the location information of each electrode.

3. The control system of claim 2, wherein, The location information is coordinate information. Before obtaining the location information of the current electrode and the other unstimulated electrodes in the electrode distribution map, the method further includes: A first test signal is applied between any two electrodes among the M electrodes; Measure the impedance between any two electrodes; Based on a preset impedance-distance mapping relationship, the measured impedance between any two electrodes is converted into spatial distance information between the two electrodes. Using any one of the M electrodes as a spatial reference, three-dimensional spatial coordinates are calculated based on all the spatial distance information to obtain the coordinate information of each electrode in three-dimensional space; An electrode distribution map is generated based on the coordinate information of each electrode in three-dimensional space; Wherein, the amplitude of the first test signal is less than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the first test signal is less than the pulse width of the stimulation signal when the DRG is electrically stimulated.

4. The control system of claim 2, wherein, The location information is coordinate information. Before obtaining the location information of the current electrode and the other unstimulated electrodes in the electrode distribution map, the method further includes: Control the target electrode among the M electrodes to output a second test signal, wherein the target electrode is any one of the M electrodes; The electrodes other than the target electrode are controlled as listening electrodes to collect neural evoked compound action potentials triggered by the second test signal; The time delay between the second test signal output by the target electrode and the neural evoked compound action potential acquired by each of the listening electrodes is obtained. Based on a preset delay-distance mapping relationship, the measured time delay is converted into spatial distance information between the target electrode and each of the listening electrodes; Using the target electrode as a spatial reference, three-dimensional spatial coordinates are calculated based on all the spatial distance information to obtain the coordinate information of each electrode in three-dimensional space. An electrode distribution map is generated based on the coordinate information of each electrode in three-dimensional space.

5. The control system according to claim 2, characterized in that, The location information is coordinate information. Before obtaining the location information of the current electrode and the other unstimulated electrodes in the electrode distribution map, the method further includes: The implantable pulse generator receives coordinate calibration data from an external programmable device. The coordinate calibration data includes the coordinate information of the M electrodes in three-dimensional space extracted from human medical images. An electrode distribution map is generated based on the coordinate information of each electrode in three-dimensional space.

6. The control system according to claim 2, characterized in that, The implantable pulse generator is also configured to: The electrode distribution map is updated when the preset update conditions are met; The preset update conditions include at least one of the following: system initialization; reaching a preset update cycle; or detecting that the impedance change between any two electrodes exceeds a preset offset threshold.

7. The control system according to claim 1, characterized in that, The step of acquiring spatial distance information between the current electrode and each unstimulated electrode after the current electrode has completed electrical stimulation includes: After the current electrode has been electrically stimulated, a third test signal is applied between the current electrode and each of the electrodes that have not been electrically stimulated. Measure the impedance between the current electrode and each of the unstimulated electrodes; Based on a preset impedance-distance mapping relationship, the measured impedance between the current electrode and each of the unstimulated electrodes is converted into spatial distance information between the current electrode and each of the unstimulated electrodes. Wherein, the amplitude of the third test signal is less than the amplitude of the stimulation signal when the DRG is electrically stimulated; and / or, the pulse width of the third test signal is less than the pulse width of the stimulation signal when the DRG is electrically stimulated.

8. The control system according to claim 1, characterized in that, The step of acquiring spatial distance information between the current electrode and each unstimulated electrode after the current electrode has completed electrical stimulation includes: After the current electrode completes electrical stimulation, the current electrode is controlled to output a fourth test signal; Each unstimulated electrode is controlled as a listening electrode to collect neural evoked compound action potentials triggered by the fourth test signal. The time delay between the fourth test signal output by the current electrode and the neural evoked compound action potential acquired by each of the monitoring electrodes is obtained. Based on a preset delay-distance mapping relationship, the measured time delay is converted into spatial distance information between the current electrode and each unstimulated electrode.

9. The control system according to claim 1, characterized in that, The implantable pulse generator is also configured to: At the start of one of the stimulation cycles, an electrode is randomly selected from the M electrodes as the first electrode to perform electrical stimulation.

10. The control system according to claim 1, characterized in that, The implantable pulse generator is also configured to: If the spatial distance between the current electrode and the electrode for the next electrical stimulation is less than or equal to a preset spatial distance threshold, then the amplitude and / or pulse width of the next electrical stimulation are reduced.

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