A peripheral nerve stimulation circuit and control method thereof

Abstract

The present invention discloses a peripheral nerve stimulation circuit and a control method thereof, comprising an implanted electrode, an adapter, a first cable, a stimulator and a body surface electrode; the implanted electrode comprises at least two electrodes; one end of the adapter is electrically connected to the implanted electrode, and the other end of the adapter is electrically connected to the stimulator through the first cable, and the stimulator is used to send electrical stimulation pulses; the body surface electrode is electrically connected to the stimulator, and forms a plurality of different stimulation circuits with the implanted electrode through stimulated human tissue. The peripheral nerve stimulation circuit and the control method thereof provided by the present invention can effectively suppress pain and improve clinical treatment effects.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a peripheral nerve stimulation circuit and a control method thereof. Background Art

[0002] As we all know, pain is a disease that is difficult to cure for humans, and the pain mechanism is extremely complex. Electrical stimulation therapy has a long history, including implantable spinal nerve stimulators, non-implantable epidermal stimulation, and peripheral nerve therapy with percutaneous implanted electrodes and external electrical stimulators. Although these devices relieve pain for patients and improve their quality of life, these stimulation systems have various defects and deficiencies, as well as differences in the patient's anatomical structure, insufficient electrical stimulation energy (including electrode displacement), and electrical stimulation that cannot cover the target of the pain nerve, which leads to the inability to effectively suppress the patient's pain.

[0003] Patent documents with patent numbers US4556051 applied for in 1985 and US5830151 applied for in 1998 disclosed treatment methods and equipment for peripheral nerve electrical stimulation. Although peripheral nerve electrical stimulation treatment has a long history, it is not widely used in practice because the effectiveness of electrical stimulation provided by surface electrodes is poor and the electrical stimulator is relatively large and inconvenient to wear.

[0004] The transcutaneous stimulation system disclosed in the patent document with publication number US20180056066A1 generates a loop between the implanted electrode and the epidermal electrode to achieve the effect of nerve electrical stimulation. However, the epidermal electrode in this system can only be placed below the stimulator. If it is on the surface of the human body where the stimulator is not convenient to place, the surface electrode cannot be realized, which reduces the range of placement of many surface electrodes and may not reach the optimal path of stimulation, resulting in limited effect of treating nerve pain in patients. The most important thing is that the above patent has only a single implanted electrode, which can only achieve unipolar stimulation of the peripheral nerve implant electrode and stimulation of a single path. The effect of peripheral nerve stimulation is affected by the relative position of the stimulating electrode and the target nerve. Only when the target nerve is located in the stimulation path can the stimulation effect be produced. Similarly, if the electrode and the target nerve are close, the stimulation current can easily cover the target nerve, which is easy to produce a better effect, otherwise, it is difficult to have an effect. Therefore, the stimulation effect of a single electrode is easily affected by the implantation position. Even if the electrode is in place during implantation, the implanted electrode may shift over time. In addition, a single implanted electrode cannot perform bipolar or multipolar stimulation in the body. All of the above affect the effectiveness of a single implanted electrode system in stimulating nerves and treating pain.

[0005] In addition, the transcutaneous stimulation system disclosed in the patent document with publication number US20180056066A1 has a square wave current pulse with fixed amplitude and frequency. After the doctor selects the stimulation program, these parameters are fixed. The pulse waveform template is the smallest stimulation unit, which consists of a stimulation phase pulse and a balance phase pulse, referred to as a stimulation pulse. Studies have shown that different nerve fibers have different response spectra to stimulation, and the spectrum of the stimulation pulse also affects the propagation distance of the stimulation current. For example, a slowly rising pulse current can affect deeper nerves. The effect of the sparse wave pulse sequence output by alternating low and high frequencies is better than that of a single frequency. The stimulators of the above patents and most of the existing stimulators can only output a single frequency square wave voltage or current stimulation pulse waveform with a fixed rising edge, lacking the possibility of selecting the target nerve, and thus having corresponding limitations on suppressing pain. Moreover, stimulation with constant amplitude and frequency can easily cause fatigue and desensitization in the nervous system, thereby affecting the therapeutic effect. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a peripheral nerve stimulation circuit and a control method thereof, which can effectively suppress pain and improve clinical treatment effects.

[0007] In order to solve the above technical problems, the present invention provides a peripheral nerve stimulation circuit, including an implanted electrode, an adapter, a first cable, a stimulator and a surface electrode; the implanted electrode includes at least two electrodes; one end of the adapter is electrically connected to the implanted electrode, and the other end of the adapter is electrically connected to the stimulator through the first cable, and the stimulator is used to send electrical stimulation pulses; the surface electrode is electrically connected to the stimulator, and forms a plurality of different stimulation circuits with the implanted electrode through the stimulated human tissue.

[0008] Furthermore, the implanted electrode includes a first electrode and a second electrode, and any one electrode or a combination of any two electrodes among the first electrode, the second electrode and the body surface electrode can be used as a stimulation electrode or a loop electrode, and together with the remaining one or two electrodes, form six stimulation loops through the stimulated human tissue.

[0009] Furthermore, the body surface electrode is a movable body surface electrode, which is electrically connected to the stimulator via a second cable and can be placed at a desired part of the human body.

[0010] Furthermore, the stimulator is a three-channel bidirectional current pulse stimulator, including a stimulation controller and a pulse generator, the pulse generator includes at least one pulse source, and the stimulation controller includes a waveform generator, a clock reference circuit, a voltage reference circuit, a digital-to-analog converter, and an amplitude and frequency modulator, which are used to control the output amplitude, current direction, pulse width and timing of the pulse source.

[0011] Furthermore, the pulse generator includes three independently controllable bidirectional current pulse sources, one of which drives the body surface electrode, and the other two pulse sources drive the first electrode and the second electrode of the implanted electrode respectively.

[0012] Furthermore, the pulse generator includes a single unidirectional current pulse source, and the stimulation pulse output by the current pulse source is distributed to the body surface electrode, the first electrode and / or the second electrode through an output switching switch.

[0013] Furthermore, the stimulation waveform output by the stimulator includes a square wave, a trapezoidal wave, a sine wave and an asymmetric wave.

[0014] Furthermore, the stimulation waveform output modes of the stimulator include constant amplitude and constant frequency pulse sequences, key-shift amplitude and frequency modulation, sinusoidal wave amplitude and frequency modulation, triangle wave amplitude and frequency modulation, and sawtooth wave amplitude and frequency modulation modes, and the output modes can be programmed as continuous timing output or intermittent timing output.

[0015] In order to solve the above technical problems, the present invention also provides a control method for a peripheral nerve stimulation circuit, comprising the following steps: Step S1: providing at least one current stimulation pulse waveform template, each waveform module starts stimulation with a stimulation phase pulse at the stimulation phase time, and then follows a balance phase pulse or a balance phase short-circuit discharge at the balance phase time for charge neutralization; Step S2: selecting a bidirectional current pulse stimulator to generate a selected waveform signal, and controlling the current flow direction of each stimulation circuit to be opposite at the stimulation phase time and the balance phase pulse time; Step S3: controlling the total of the stimulation pulse charge and the balance charge so that the two remain balanced within a certain time interval.

[0016] Furthermore, the method further includes step S4, adjusting the current amplitude and pulse width according to the electrode surface area, and controlling the current density D of the monophasic pulse and the monophasic stimulation charge Q to satisfy Log(D*Q)≤1.85.

[0017] Furthermore, the step S4 uses a constant frequency and horizontal stimulation mode to output continuous stimulation pulses to the designated electrodes according to the set pulse frequency and the upper and lower limits of the adjustable amplitude.

[0018] Furthermore, the step S4 adopts an analog modulation stimulation mode to determine the maximum and minimum values ​​of the amplitude or frequency according to the modulation period, the average amplitude value or the average frequency value, and the modulation depth percentage, and outputs continuous stimulation pulses to the designated electrode; the analog modulation method includes sinusoidal wave modulation, triangle wave modulation and sawtooth wave modulation.

[0019] Furthermore, the step S4 adopts a key-shift modulation stimulation mode to perform amplitude or frequency modulation on the selected stimulation pulse, or simultaneously performs two-level jump switching modulation of amplitude shift keying and frequency shift keying at specified intervals.

[0020] Furthermore, the stimulator also includes an electrode voltage detection unit, which measures the impedance of the implanted electrode by outputting a fixed small current pulse to detect the voltage of the implanted electrode, so as to determine the integrity of the implanted electrode or track the change of the impedance of the implanted electrode over time.

[0021] Furthermore, the integrity judgment process of the implanted electrode is as follows: if the measured impedance of the implanted electrode is within a preset range, the implanted electrode is deemed to be intact; if the measured impedance of the implanted electrode is less than the preset range, it is determined that a short circuit has occurred in the implanted electrode; if the measured impedance of the implanted electrode is greater than the preset range, it is determined that the implanted electrode is loose or has fallen off.

[0022] Furthermore, the fixed small current pulse does not exceed 0.5 mA, and the preset range of the impedance of the implanted electrode is 100-2000 ohms.

[0023] Furthermore, when it is tracked that the impedance of the implanted electrode decreases over time and exceeds a preset threshold, it is prompted to change the stimulation waveform, stimulation mode or stimulation intensity for stimulation.

[0024] Furthermore, the stimulator also includes a neural signal detection unit, which includes a neural signal amplifier and a neural signal processor. The neural signal detection unit uses a stimulating electrode as a neural signal detection electrode and a non-stimulating electrode as a reference electrode or signal ground to measure neural and electromyographic signals.

[0025] Furthermore, the neural signal processor first outputs a current pulse to stimulate the target neural tissue, and simultaneously closes the neural signal detection channel to avoid blocking the high-gain neural signal amplifier. After the stimulation pulse is completed, a charge release cycle is immediately added to release the residual charge left on the output capacitor by the stimulation pulse through a short-circuit switch to reduce the DC drift interference of the electrode potential. After the charge release cycle is completed, the neural signal detection channel is opened to record the response signal formed by the action potential of the nerve caused by the stimulation as a feedback signal to adjust the stimulation intensity.

[0026] Furthermore, it also includes installing stimulation programming software for doctors on a mobile terminal or PC, and providing the following control steps on the stimulation programming software interface: selecting and configuring stimulation electrodes and loop electrodes; selecting a waveform template, and setting the amplitude, frequency, pulse width, phase width and level according to the selected waveform; selecting a continuous modulation mode or a key shift control mode; providing the following parameter configurations for the continuous modulation mode: modulation mode, modulation depth, intermittent stimulation cycle and duty cycle; providing the following parameter configurations for the key shift control mode: key shift cycle, key shift frequency, key shift amplitude, intermittent stimulation cycle and duty cycle; directly controlling the stimulator to stimulate according to the selected stimulation electrode, stimulation waveform, stimulation mode and stimulation intensity.

[0027] Furthermore, it includes a remote controller, which is connected to the stimulator via wireless communication, and the stimulation programming software provides a storage function. The remote controller stores stimulation program numbers corresponding to the program table contents in the solid-state memory of the stimulator, and the remote controller stores stimulation intensity numbers corresponding to the intensity table contents in the solid-state memory of the stimulator.

[0028] Compared with the prior art, the present invention has the following beneficial effects: the peripheral nerve stimulation circuit and control method thereof provided by the present invention, the three electrodes consisting of the double electrodes and the body surface electrodes can form six different stimulation pathways consisting of stimulation electrodes and loop electrodes, and each stimulation pathway may act on different nerve tissues. Moreover, in the case of a combination of two electrodes, by distributing the current intensity between the two electrodes and controlling the overall flow direction of the current, the effect of reaching the virtual electrode is provided, which provides new possibilities for improving the stimulation effect. In addition, an extended movable body surface electrode connected to the stimulator is provided, so that it can be placed in any part of the patient that needs stimulation, such as being placed in a part that is particularly sensitive to stimulation, which can more effectively suppress pain. Finally, a variety of novel stimulation waveform templates such as square waves, trapezoidal waves and sine waves are provided, and the changes and combinations of the pulse width, frequency and amplitude of these waveforms are used to enhance the effect of clinical treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a peripheral nerve stimulation system according to an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of a patient using a peripheral nerve stimulation system according to an embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of a peripheral nerve stimulation circuit in an embodiment of the present invention;

[0032] FIG4 (a) is a schematic diagram of six possible stimulation paths of three electrodes in an embodiment of the present invention, and FIG4 (b) is a schematic diagram of virtual electrodes formed by distributing currents of two electrodes of an electrode combination differently and changing the direction of the total current in an embodiment of the present invention;

[0033] Figure 5 (a) is a schematic diagram of a stimulation circuit formed by a stimulation electrode and a loop electrode in an embodiment of the present invention, Figure 5 (b) is a schematic diagram of the working principle of the bidirectional current pulse source in an embodiment of the present invention;

[0034] Figure 6 is a circuit diagram of a stimulator in another embodiment of the present invention;

[0035] Figure 7 (a) is a schematic diagram of the measurement circuit structure of the stimulator in an embodiment of the present invention; Figure 7 (b) is a schematic diagram of the neural response signal measurement process in an embodiment of the present invention;

[0036] Figure 8 Schematic diagram of five stimulation pulse waveform templates in an embodiment of the present invention;

[0037] Figure 9a Schematic diagram of a constant frequency and constant amplitude continuous stimulation mode and an intermittent stimulation mode in an embodiment of the present invention; Figure 9b Schematic diagram of a dual-frequency pulse continuous stimulation mode and an intermittent stimulation mode in an embodiment of the present invention;

[0038] Fig.10 is a schematic diagram of an analog amplitude modulation stimulation mode in an embodiment of the present invention, wherein the modulation modes include sine wave, triangle wave and sawtooth wave modulation;

[0039] Fig.11 A schematic diagram of a simulated frequency modulation stimulation mode in an embodiment of the present invention, wherein the modulation modes include sine wave, triangle wave and sawtooth wave modulation;

[0040] Fig.12 Schematic diagram of a key-shift modulation stimulation mode in an embodiment of the present invention, wherein the modulation modes include amplitude shift keying, frequency shift keying, and a combination of amplitude shift and frequency shift keying;

[0041] Fig.13 It is a structural schematic diagram of a method for realizing stimulation modulation by a stimulation controller in an embodiment of the present invention;

[0042] Fig.14 A schematic diagram of a flow chart of patient debugging settings for implementing a stimulation prescription in an embodiment of the present invention;

[0043] Fig.15 Schematic diagram of the programming interface of the stimulation programmer used by doctors in an embodiment of the present invention.

[0044] In the figure:

[0045] 1-subcutaneous tissue, 2-wound, 3-patient, 10-implanted electrode, 20-adapter, 30-first cable, 40-third cable, 50-stimulator, 51-stimulation controller, 52-pulse generator, 521-pulse source, 60-remote control, 66-tablet computer, 70-body surface electrode, 72-second cable, 80-movable body surface electrode, 100-stimulation programmer, 111-first electrode, 112-second electrode. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0047] See also Figure 1 and Figure 3 The present embodiment provides a peripheral nerve stimulation circuit, comprising an implanted electrode 10, an adapter 20, a first cable 30, a stimulator 50 and a surface electrode 70; the implanted electrode 10 comprises at least two electrodes, and the implanted electrode 10 can be percutaneously inserted into the patient's body. In a specific embodiment, the number of electrodes is 2, namely a first electrode 111 and a second electrode 112; one end of the adapter 20 is electrically connected to the implanted electrode 10, and the other end of the adapter 20 is electrically connected to the stimulator 50 through the first cable 30, and the stimulator 50 is used to send electrical stimulation pulses; the surface electrode 70 is electrically connected to the stimulator 50, and forms a plurality of different stimulation circuits with the implanted electrode 10 through the stimulated human tissue.

[0048] See also Figure 2, a stimulation system using the peripheral nerve stimulation circuit of the present invention, the body surface electrode 70 takes the movable body surface electrode 80 as an example, when in use, the implant electrode 10 having the first electrode 111 and the second electrode 112 is percutaneously implanted near the target nerve in the body of the patient 3, the adapter 20 is placed on the skin of the patient 3, the stimulator 50 is fixed to the body surface of the patient 3, and the movable body surface electrode 80 is placed at the place where the patient 3 needs stimulation through the second cable 72. During the treatment process, the patient 3 selects the stimulation program and stimulation intensity through the remote control 60, and the stimulator 50 is used to stimulate the target part. In addition, the system also includes a stimulation programmer 100 implemented by the doctor using a tablet computer. During the electrode implantation process, the doctor determines the integrity and function of the electrode by operating the control interface of the stimulation programmer 100. In another embodiment, the doctor debugs and determines the stimulation plan (program) through the programming interface of the stimulation programmer 100, including the waveform, modulation method and safe stimulation intensity range, and fixes these parameters into the stimulator 50. The patient uses the remote control 60 to select a stimulation program and stimulation intensity by selecting a number. The Bluetooth communication transmits the control information to the stimulator 50. The stimulator 50 generates a specific current pulse sequence according to the selected program, which is output to the target neural tissue through the external wire, the adapter 20 and one of the implanted electrodes, and forms a stimulation circuit through another electrode in the implanted electrode 10 or the designated surface electrode 70.

[0049] Please continue to see Figure 3The stimulator 50 is a three-channel bidirectional current pulse stimulator, including a stimulation controller 51 and a pulse generator 52. The pulse generator 52 includes at least one pulse source 521. The stimulation controller 51 controls the output amplitude, current direction, pulse width and / or timing of the pulse source 521. The stimulation controller 51 is a microprocessor or a dedicated control chip for the stimulator. In another embodiment, the three-channel pulse generator 52 is implemented by three independent bidirectional current pulse sources 521 as electrode drivers (Driver). Each pulse source 521 can be controlled to generate cathode (N) and anode (P) current pulses. One of the pulse sources 521 drives the body surface electrode 70, and the remaining two drive the two implanted first electrodes 111 and the second electrode 112 respectively. In this embodiment, the output function and performance of each channel are equivalent (Indifferent), that is, any electrode or a combination of two electrodes can be used as a stimulation electrode (cathode) or a loop electrode (anode), and form a stimulation loop with the remaining one or two electrodes. Therefore, the three electrodes can form six different stimulation pathways consisting of stimulation electrodes and loop electrodes, as shown in Figure 4 (a). Each stimulation pathway may have an effect on different neural tissues, or in other words, under the same electrode implantation conditions, there are six possible stimulation options. Moreover, as shown in Figure 4 (b), in the case of a two-electrode combination, by distributing the current intensity between the two electrodes, the overall flow direction of the current (Current Steering) can be controlled to achieve the effect of the virtual electrode, thereby providing new possibilities for improving the stimulation effect. When stimulation occurs, the pulse source of the stimulation electrode and the pulse source of the loop electrode form a "bridge" push-pull output mode, such as Figure 5 As shown in (a), during the stimulation phase, the current flows from the anode to the cathode, and in the equilibrium phase, the current reverses, as shown in Figure 5 (b) shown.

[0050] See also Figure 6 In another embodiment, the stimulator 50 includes a single unidirectional current pulse source. In this embodiment, three stimulation channels share a unidirectional current pulse source driver, and the stimulation pulse output by the driver is distributed to one or more designated electrodes by the output switching switch, that is, the stimulation pulse output by the current pulse source is distributed to the body surface electrode 70, the first electrode 111 and / or the second electrode 112 through the output switching switch. The switching of the stimulation phase and the balance phase direction of the current pulse is also achieved by the output switching switch. This design can also achieve six stimulation circuits through electrode combinations, as shown in Figure 4 (a). However, this design cannot achieve a controllable virtual electrode as shown in Figure 4 (b). This design can achieve the effect of reducing circuit power consumption and reducing circuit elements.

[0051] In any of the above embodiments, the stimulator 50 also includes an electrode voltage detection unit, which measures the impedance of the implanted electrode by outputting a fixed small current pulse to detect the voltage of the implanted electrode, so as to judge the integrity of the implanted electrode or track the change of the impedance of the implanted electrode over time. Specifically, the integrity judgment process of the implanted electrode is as follows: if the measured impedance of the implanted electrode is within a preset range, the implanted electrode is deemed to be intact; if the measured impedance of the implanted electrode is less than the preset range, the implanted electrode is determined to be short-circuited; if the measured impedance of the implanted electrode is greater than the preset range, the implanted electrode is determined to be loose or detached. Furthermore, the fixed small current pulse does not exceed 0.5 mA, and the preset range of the impedance of the implanted electrode is 100 to 2000 ohms. When it is tracked that the impedance of the implanted electrode decreases over time and exceeds a preset threshold, it is prompted to change the stimulation waveform, stimulation mode or stimulation intensity for stimulation.

[0052] At the same time, the dual implanted electrode structure also facilitates the detection of nerve response signals to stimulation pulses. Figure 7 In the embodiment shown in (a), the stimulator also includes a neural signal detection unit, which includes a neural signal amplifier and a neural signal processor. The neural signal detection unit uses the stimulating electrode as the detection electrode and uses the non-stimulating electrode as the reference electrode or signal ground. The neural signal detection process is reflected in the following Figure 7 In the implementation scheme of (b), first, the stimulator outputs a current pulse to stimulate the target nerve tissue, and at the same time closes the nerve signal detection channel to avoid blocking the high-gain nerve signal amplifier. After the stimulation pulse is completed, a charge release cycle is immediately added to release the residual charge left on the output capacitor by the stimulation pulse through the short-circuit switch to reduce interference such as DC drift of the electrode potential. After the charge release cycle is over, the nerve signal detection channel is opened to record the response signal formed by the action potential of the nerve caused by the stimulation. All the timing of the signal detection process is set according to the signal conduction characteristics of the target nerve to achieve the best recording effect. The recorded nerve response signal can be used for clinical diagnosis or as stimulation feedback to adjust the stimulation intensity.

[0053] See also Figure 8In addition to the default square wave stimulation pulse, the stimulation system provided by the present invention adds four new current stimulation pulse waveform templates, namely trapezoidal, sinewave, asymmetric and passively balanced. Each waveform module starts with a stimulation phase pulse with an amplitude of A1 and a width of tx, followed by a balance phase pulse with an amplitude of A2 and a width of tz responsible for charge neutralization. An adjustable inter-wave delay ty is set between the two-phase pulses. If the balance phase is set to a current pulse for rapid neutralization, it is an active balanced stimulation. Regardless of the waveform template used, the safety of the stimulation requires that the charges of the stimulation phase and the balance phase are equal, that is, Q1=Q2, where Q1 and Q2 are the integrals of the current pulse waveform within the pulse width, that is . At the same time, the maximum stimulation intensity of the monophasic pulse is also subject to the Shannon Criteria, that is, K=Log(D*Q)≤1.85. Where D is the current density of the monophasic pulse, milliamperes per square centimeter, which is related to the electrode surface area, and Q is the monophasic stimulation charge, which is related to the current amplitude and pulse width. The latest research shows that for peripheral nerve stimulation, the K value can exceed 1.85, but this limit can be adjusted through the stimulator's software. The equilibrium phase can also use short-circuit discharge instead of current pulses, that is, passive balanced stimulation. Passive balanced stimulation can save the stimulation current of the equilibrium phase, but the required discharge time is long and it is not suitable for high-frequency stimulation. If the stimulation phase and the equilibrium phase use the same pulse form, it is symmetrical stimulation. Conversely, if different pulse forms are used, it is asymmetrical stimulation. In asymmetrical stimulation, the charges of the two stimulation phases may be unbalanced, but the sum of the charges of the stimulation pulse and the equilibrium pulse should be balanced within a certain time interval. The default values ​​of each parameter of the stimulation pulse waveform are adjusted to the optimal default values ​​through clinical trials, but doctors can further adjust them through the stimulation programmer according to the patient's response to the stimulation.

[0054] Both trapezoidal waves and sine waves have slow rising and falling edges, which reduce the high-frequency components of the stimulation pulse. Reported clinical studies have shown that stimulation or electric field changes with high-frequency components can easily excite (activate) nerves close to the electrode, while low-frequency stimulation allows the electric field changes caused by stimulation to travel farther, thus being effective on nerves that are far from the electrode. After the electrode is implanted, its position is fixed, and thus the relative position of the electrode and each nerve tissue is also fixed. Trapezoidal waves and sine waves provide us with the possibility of stimulating the target nerve in a targeted and selective manner after the electrode is implanted.

[0055] In addition to providing a variety of stimulation waveforms, the stimulator also provides a variety of stimulation modes, that is, dynamically modulating the amplitude or frequency of the stimulation pulse sequence in different ways, and arranging the stimulation program to output the modulated pulse sequence (called a stimulation module) continuously or intermittently at a specified time, in a specified manner, and within a specified intensity range. Embodiments of the stimulation module provided by the present invention include:

[0056] 1. Constant frequency banner stimulation mode: The stimulator outputs continuous stimulation pulses to the specified electrodes according to the selected stimulation pulse waveform, frequency and amplitude, such as Figure 9a The stimulation program selects continuous output or intermittent output mode and specifies the pulse frequency and the upper and lower limits of the adjustable amplitude. The patient can adjust the stimulation intensity, that is, the amplitude between the upper and lower limits of the stimulation pulse, according to the effect he feels. When using intermittent output, the patient can also choose to slowly increase or decrease the amplitude (Ramp-up and Ramp-down) to increase or decrease the stimulation intensity smoothly and increase comfort. In addition, this stimulation mode also includes dual-frequency stimulation sequences, such as Figure 9b Dual-frequency stimulation adds a slow interference frequency to the main frequency and is used in some special stimulation cases.

[0057] 2. Analog (continuous) modulation stimulation mode: The stimulator continuously modulates the amplitude or frequency of the selected stimulation pulse waveform using different analog methods, such as Fig.10 and Fig.11 As shown. Analog modulation methods include sine wave modulation, triangle wave modulation and sawtooth wave modulation. This mode adds a modulation frequency to the basic stimulation element, which is called interference frequency. Interference frequency may have a certain stimulation effect on specific symptoms. However, the main purpose of this stimulation mode is to reduce or even eliminate the rapid disappearance of the therapeutic effect caused by nerve sensory desensitization (habituation) and fatigue (fatigue) caused by extracellular electrical stimulation of nerve cells (extracellular stimulation). The control parameters of the analog modulation mode include modulation period, average amplitude value or average frequency value, and modulation depth percentage, which can determine the maximum and minimum values ​​of the amplitude or frequency.

[0058] 3. Key shift modulation stimulation mode: The stimulator performs two-level jump switching of amplitude or frequency of the selected stimulation pulse or simultaneously performs amplitude shift keying (Amplitude Shift Keying) and frequency shift keying (Frequency Shift Keying) at specified intervals, such as Fig.12As shown. Research on the principle of transcutaneous electrical stimulation analgesia shows that the analgesic effect of interactive stimulation with low frequency and high current and high frequency and low current is better than stimulation with a single frequency or two frequencies at the same time at different stimulation points. The adjustment parameters of key-shift stimulation include high amplitude and low amplitude, high frequency and low frequency, modulation frequency, and modulation duty cycle, that is, the proportion of high value time in the modulation cycle.

[0059] See also Fig.13 In one embodiment, the stimulation waveform and modulation stimulation mode functions of the stimulator are mainly implemented by a stimulation controller. The stimulation controller includes a waveform generator, a clock reference, a voltage reference, a digital-to-analog converter, and an amplitude and frequency modulator.

[0060] See also Fig.14 The neurostimulation system provides a patient-specific stimulation plan, or "stimulation prescription". Each patient's stimulator has a specific stimulation plan, including the appropriate stimulation waveform, stimulation program, and effective range of stimulation intensity. The stimulation plan is implemented through the "patient fitting" procedure. Patient fitting is performed in a hospital or clinic, and the required settings are as follows: Fig.14 As shown. The doctor uses the doctor programming interface (Clinician App) to select parameters such as stimulation electrodes, stimulation waveforms, stimulation modes and stimulation intensity, and directly controls the stimulator to stimulate. The doctor evaluates the selected stimulation parameters through the patient's feedback to determine the stimulation mode, stimulation program and corresponding effective stimulation intensity range suitable for the patient. The result of the patient's debugging is a stimulation prescription suitable for the patient, which is sintered in the solidification memory of the stimulator in the form of a table. The patient selects the corresponding table directory number in the memory of the stimulator through the remote control, including the stimulation program and stimulation intensity. Fig.15 An embodiment of a programming interface for a physician-use stimulation programmer.

[0061] In summary, the present invention has at least the following advantages: 1. The three electrodes consisting of the dual electrodes and the surface electrodes can form six different stimulation pathways consisting of stimulation electrodes and loop electrodes, and each stimulation pathway may act on different neural tissues, thereby increasing the stimulation range and improving the effectiveness of treatment. Moreover, in the case of a combination of two electrodes, by distributing the current intensity between the two electrodes and controlling the overall flow direction of the current, the effect of the virtual electrode is achieved, providing new possibilities for improving the stimulation effect. 2. More effective neural regulation is provided through novel stimulation waveforms and pulse modulation methods; 3. The movable surface electrodes can be placed on any part of the patient that needs stimulation, which can increase the stimulation range and make neural regulation more effective.

[0062] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A peripheral nerve stimulation circuit, characterized in that: It includes an implanted electrode, an adapter, a first cable, a stimulator and a body surface electrode; The implanted electrode comprises a first electrode and a second electrode, any one electrode or any combination of the first electrode, the second electrode and the body surface electrode can be used as a stimulation electrode or a loop electrode, and the remaining one or two electrodes form six stimulation loops through stimulated human tissues, the body surface electrode is a movable body surface electrode, the movable body surface electrode is electrically connected to the stimulator through a second cable, and can be placed at a desired part of the human body; One end of the adapter is electrically connected to the implanted electrode, and the other end of the adapter is electrically connected to the stimulator through the first cable, and the stimulator is used to send electrical stimulation pulses; The body surface electrodes are electrically connected to the stimulator and form a plurality of different stimulation circuits with the implanted electrodes through the stimulated human tissues; The stimulator further comprises an electrode voltage detection unit, which measures the impedance of the implanted electrode by outputting a fixed small current pulse to detect the voltage of the implanted electrode, so as to judge the integrity of the implanted electrode or track the change of the impedance of the implanted electrode over time; When it is tracked that the impedance of the implanted electrode decreases over time and exceeds a preset threshold, a prompt is given to change the stimulation waveform, stimulation mode or stimulation intensity for stimulation; the integrity judgment process of the implanted electrode is as follows: if the measured impedance of the implanted electrode is within a preset range, the implanted electrode is deemed to be intact; if the measured impedance of the implanted electrode is less than the preset range, it is determined that the implanted electrode is short-circuited; if the measured impedance of the implanted electrode is greater than the preset range, it is determined that the implanted electrode is loose or detached; The stimulator further comprises a neural signal detection unit, which comprises a neural signal amplifier and a neural signal processor, and the neural signal detection unit uses the stimulating electrode as a neural signal detection electrode and uses the non-stimulating electrode as a reference electrode or a signal ground to measure neural and electromyographic signals; The neural signal processor first outputs a current pulse to stimulate the target neural tissue and simultaneously closes the neural signal detection channel to avoid blocking the high-gain neural signal amplifier. After the stimulation pulse is completed, a charge release cycle is immediately added to release the residual charge left on the output capacitor by the stimulation pulse through a short-circuit switch to reduce the DC drift interference of the electrode potential. After the charge release cycle is completed, the neural signal detection channel is opened to record the response signal formed by the action potential of the nerve caused by the stimulation as a feedback signal to adjust the stimulation intensity.

2. The peripheral nerve stimulation circuit according to claim 1, characterized in that: The stimulator is a three-channel bidirectional current pulse stimulator, including a stimulation controller and a pulse generator. The pulse generator includes at least one pulse source. The stimulation controller includes a waveform generator, a clock reference circuit, a voltage reference circuit, a digital-to-analog converter, and an amplitude and frequency modulator, which are used to control the output amplitude, current direction, pulse width and timing of the pulse source.

3. The peripheral nerve stimulation circuit according to claim 2, characterized in that: The pulse generator comprises three independently controllable bidirectional current pulse sources, one of which drives the body surface electrode, and the other two pulse sources drive the first electrode and the second electrode of the implanted electrode respectively.

4. The peripheral nerve stimulation circuit according to claim 2, characterized in that: The pulse generator comprises a single unidirectional current pulse source, and the stimulation pulse output by the current pulse source is distributed to the body surface electrode, the first electrode and / or the second electrode through an output switching switch.

5. The peripheral nerve stimulation circuit according to claim 2, characterized in that: The stimulation waveform output by the stimulator includes a square wave, a trapezoidal wave, a sine wave and an asymmetric wave.

6. The peripheral nerve stimulation circuit according to claim 2, characterized in that: The stimulation waveform output modes of the stimulator include constant amplitude and constant frequency pulse sequences, key-shift amplitude and frequency modulation, sinusoidal wave amplitude and frequency modulation, triangle wave amplitude and frequency modulation, and sawtooth wave amplitude and frequency modulation modes. The output modes are programmable as continuous timing output or intermittent timing output.

7. A method for controlling a peripheral nerve stimulation circuit according to any one of claims 1 to 6, characterized in that: The steps include: Step S1: providing at least one current stimulation pulse waveform template, each waveform module starts stimulation with a stimulation phase pulse at a stimulation phase time, and then follows a balance phase pulse or a balance phase short-circuit discharge to neutralize the charge at a balance phase time; Step S2: Select a bidirectional current pulse stimulator to generate a selected waveform signal, and control the current flow direction of each stimulation circuit to be opposite during the stimulation phase and the balance phase; Step S3: Control the total of the stimulation pulse charge and the balance charge so that the two are balanced within a certain time interval.

8. The control method of the peripheral nerve stimulation circuit according to claim 7, characterized in that: The method further includes step S4, adjusting the current amplitude and pulse width according to the electrode surface area, and controlling the current density D of the monophasic pulse and the monophasic stimulation charge Q to satisfy Log(D*Q)≤1.

85.

9. The control method of the peripheral nerve stimulation circuit according to claim 8, characterized in that: The step S4 uses a constant frequency and constant amplitude stimulation mode to output continuous stimulation pulses to the designated electrodes according to the set pulse frequency and the upper and lower limits of the adjustable amplitude.

10. The control method of the peripheral nerve stimulation circuit according to claim 8, characterized in that: The step S4 adopts the analog modulation stimulation mode to determine the maximum and minimum values ​​of the amplitude or frequency according to the modulation period, the average amplitude value or the average frequency value, and the modulation depth percentage, and outputs continuous stimulation pulses to the designated electrode; Analog modulation methods include sine wave modulation, triangle wave modulation and sawtooth wave modulation.

11. The control method of the peripheral nerve stimulation circuit according to claim 8, characterized in that: The step S4 adopts the key shift modulation stimulation mode to perform amplitude or frequency modulation on the selected stimulation pulse, or simultaneously performs two-level jump switching modulation of amplitude shift keying and frequency shift keying at specified intervals.

12. The control method of the peripheral nerve stimulation circuit according to claim 7, characterized in that: The fixed small current pulse does not exceed 0.5 mA, and the preset range of the impedance of the implanted electrode is 100-2000 ohms.

13. The control method of the peripheral nerve stimulation circuit according to claim 7, characterized in that: It also includes installing stimulation programming software for doctors to use on a mobile terminal or a PC, and providing the following control steps on the stimulation programming software interface: Choose to configure stimulation electrodes and loop electrodes; Select a waveform template, and set the amplitude, frequency, pulse width, phase width and level according to the selected waveform; Select continuous modulation mode or key shift modulation mode; The following parameter configurations are provided for the continuous modulation mode: modulation mode, modulation depth, intermittent stimulation period and duty cycle; The following parameter configurations are provided for the key shift control mode: key shift period, key shift frequency, key shift amplitude, intermittent stimulation period and duty cycle; Directly control the stimulator to stimulate according to the selected stimulation electrode, stimulation waveform, stimulation mode and stimulation intensity.

14. The control method of the peripheral nerve stimulation circuit according to claim 13, characterized in that: It includes a remote controller, which is connected to the stimulator via wireless communication. The stimulation programming software provides a storage function. The remote controller stores stimulation program numbers corresponding to the program table contents in the solid memory of the stimulator, and the remote controller stores stimulation intensity numbers corresponding to the intensity table contents in the solid memory of the stimulator.

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