Selective stimulation system

Abstract

The present invention relates to a selective stimulation system, comprising: a stimulator, configured to generate an electrical stimulation signal having a frequency, a pulse width, and an intensity; and at least one stimulation electrode, provided with stimulation contacts at a distal end. The stimulation electrode extends towards the head end along the course of a spinal nerve, exits from a dural sac region at the midline, exits the skin from inside to outside through an interspinous space, or is directly connected to the stimulator along a subcutaneous tunnel. The stimulation contacts provided on the stimulation electrode are elastically fixed to an exposed dorsal root nerve region in a surrounding manner, wherein the electrical resistance between the stimulation contacts and the cerebrospinal fluid is greater than the resistance between the stimulation contacts and the epineurium of the dorsal root nerve to which the stimulation contacts are elastically fixed. The present invention can solve the problem that existing stimulation electrodes are unable to effectively promote functional recovery of paralyzed lower limbs after high-level spinal cord injury due to defects between the electrodes and the spinal cord and dorsal nerve roots, such as significant individual variability in precision, poor stimulation reliability, significant influence from patient postures, and high power consumption.

Description

A selective stimulation system Technical Field

[0001] This invention relates to the field of electronic medical technology, and specifically to a selective stimulation system, particularly a spinal nerve root stimulation system, and more particularly to an implantable selective spinal nerve root stimulation system. Background Technology

[0002] Traditional treatments for spinal cord injury include medication, physical therapy, and rehabilitation training. Medication primarily relieves pain and reduces inflammation, but cannot repair damaged nerve tissue. The effectiveness of physical therapy largely depends on the patient's physical condition and rehabilitation ability. Rehabilitation training is complex and time-consuming, requiring professional guidance, and patients are prone to frustration and discouragement due to slow progress. In recent years, spinal cord electrical stimulation technology has been developed. For example, CN102202729A discloses a selective stimulation system and signal parameters for medical conditions. While it provides an improved stimulation system, device, and method for effectively delivering stimulation energy, treatment depends on electrode placement, and the therapeutic effect is primarily pain relief, not spinal cord function recovery. CN112334184A discloses mixed nerve stimulation, a technique that allows some subjects to receive effective treatment at the stimulation level. While it mentions targeting one or more proprioceptive or motor fiber types of the posterior root and / or dorsal column to treat spasticity, Parkinson's disease, or other motor control disorders, it does not disclose how the nerve stimulation is specifically performed to aid muscle activity.

[0003] Over the past five years, epidural electrical stimulation (EES) has achieved some success in neuromodulation and gait reconstruction. However, its hardware still has significant limitations in practical applications. Currently available EES devices still use traditional spinal cord stimulation electrodes for analgesia. These electrodes help patients restore motor function and improve quality of life by sequentially stimulating the spinal cord and simulating the activity of gait-related muscle groups. To some extent, patients' motor abilities have improved, and studies have shown that EES can activate key motor neural pathways to promote the coordinated contraction of specific muscle groups. However, the EES method is heavily reliant on electrode placement, as the accuracy of electrode placement directly affects the stimulation effect and precision. Poor electrode placement makes it difficult to effectively stimulate specific spinal cord regions or nerve roots, leading to a significant decrease in stimulation effect and potentially preventing the achievement of the expected functional recovery. Furthermore, current technology stimulates the dorsal column and dorsal root nerves of the spinal cord, making it difficult to selectively stimulate certain specific muscle groups.

[0004] There is cerebrospinal fluid of varying thickness between the EES electrode and the spinal cord and dorsal nerves. Due to the presence of cerebrospinal fluid, the electrical stimulation signal attenuates during transmission, thus affecting the intensity and effectiveness of the stimulation. This physiological complexity reduces the reliability and consistency of the stimulation signal. Furthermore, changes in patient position significantly impact the effectiveness of electrical stimulation. For example, sitting, standing, or lying down can alter the electrode position relative to the spinal cord or nerve roots, thus affecting the current conduction path and stimulation effect. Therefore, electrode placement and patient positioning management are crucial in clinical applications. For patients requiring precise, sequential stimulation of specific nerve roots, EES technology presents numerous limitations and challenges, thus restricting its effectiveness and stability in wider applications.

[0005] Current spinal cord stimulation (EES) technology faces key bottlenecks: First, traditional open-loop stimulation modes cannot dynamically adjust parameters according to the patient's real-time movement needs, resulting in insufficient motor coordination. For example, CN119522119A discloses a system for providing electrical stimulation to patients. This system includes an EES stimulator, a user interface device, and a controller circuit. The controller circuit is configured to: determine or adjust stimulation settings based on user input of autonomic symptoms and identifiers of affected anatomical structures; and generate control signals to the EES stimulator to deliver nerve stimulation energy according to the determined or adjusted stimulation settings to alleviate autonomic symptoms or treat autonomic disorders. Although this system can improve treatment effects through feedback regulation, its feedback input is mainly based on the patient's subjective consciousness and uses pain level as the standard. Due to individual differences in consciousness, this feedback regulation cannot truly make adaptive adjustments based on the body's objective condition, resulting in poor treatment effects. Second, the spacing between the contacts of existing EES epidural electrodes is fixed at the factory, resulting in limited spatial resolution of the contacts and making it difficult to accurately reconstruct physiological motor rhythms. Closed-loop spatiotemporal sequential biomimetic stimulation (CSBS) technology can theoretically significantly improve the motor function reconstruction effect by integrating bioelectric signal feedback and biomimetic temporal control. However, existing EES hardware systems lack a closed-loop control architecture that matches CSBS. Summary of the Invention

[0006] Following high-level spinal cord injury, the connection between the distal spinal cord and the superior central nervous system is interrupted, preventing the brain from effectively transmitting motor commands to the muscles of the lower limbs. This leads to muscle weakness or complete paralysis, and prolonged lack of movement and nerve innervation causes gradual muscle atrophy in the lower limbs, further weakening muscle strength and coordination. In recent years, most researchers have argued that the spinal cord possesses inherent functions beyond its ascending and descending motor and sensory transmission capabilities. This provides a theoretical basis for stimulating the lower spinal cord after high-level spinal cord injury to promote the recovery of motor function in the muscle groups innervated by the affected segment. EES (electrodermal stimulation) technology has gradually become one of the effective methods for treating motor disorders caused by spinal cord injury. Although some studies have attempted to use traditional epidural electrical stimulation (EDS) devices to stimulate the spinal cord, this method heavily relies on electrode placement; deviations in placement can make it difficult for the device to stimulate the target area. Furthermore, there is cerebrospinal fluid of varying thickness between the stimulating electrode and the spinal cord and dorsal nerve roots. Therefore, existing epidural electrical stimulation techniques have drawbacks such as poor reliability, significant impact of patient position, and high power consumption. In other words, existing techniques cannot accurately and effectively promote the recovery of lower limb function after high spinal cord injury, such as lower limb gait disorder.

[0007] To address the shortcomings of existing technologies, this invention provides a selective stimulation system, particularly an implantable selective spinal nerve root stimulation system comprising:

[0008] A stimulator is used to generate an electrical stimulation signal with a specific frequency, pulse width, and intensity to induce motor commands in the affected limb of a patient.

[0009] At least one stimulating electrode with a stimulating contact at its distal end extends cephalicly along the course of the cauda equina, emerges from the dural sac region at the midline, passes through the interspinous space from the inside out through the skin, or is directly connected to the stimulator along the subcutaneous tunnel.

[0010] The stimulation electrode has a stimulation contact that is elastically fixed to the freed dorsal root nerve region in a circumferential manner. The resistance of the stimulation contact to the cerebrospinal fluid is greater than the resistance between the stimulation contact and the outer perithelial membrane of the dorsal root nerve, which is elastically fixed to it. In this invention, resistance is used to express this, not to ignore the impedance when the stimulation signal is a pulse signal, but because the pulse frequency of the stimulation signal is not high, using a linear pure resistance reduces the difficulty of analysis; therefore, the scope of protection of this invention also includes impedance.

[0011] In this technical solution, the resistance between the stimulation contact and the cerebrospinal fluid is higher, while the resistance between the stimulation contact and the external membrane of the dorsal root nerve is lower. This allows the current to more easily act directly on the target nerve tissue through a path with less resistance. Specifically, the higher resistance difference makes it easier for the current to concentrate in a small area. This setting improves signal transmission quality and signal fidelity, allowing for more accurate control of nerve activation while maintaining the localization accuracy of electrical stimulation. This setting also reduces ineffective stimulation of surrounding non-target nerve tissue, avoiding unnecessary side effects. In addition, this setting reduces ineffective current passing through the cerebrospinal fluid, thereby improving energy utilization and extending battery life. In terms of biocompatibility and long-term efficacy, the low-resistance contact between the stimulation contact and the external membrane of the dorsal root nerve helps maintain good biocompatibility and mechanical stability. Furthermore, stable electrode-nerve contact ensures long-term therapeutic effects and reduces the risk of needing frequent electrode adjustments or replacements.

[0012] According to a preferred embodiment, the stimulating electrodes are arranged in pairs with stimulating contacts, wherein a certain distance is maintained between the paired stimulating contacts. This distance creates a signal loop between the paired stimulating contacts, allowing the electrical stimulation signal provided by the stimulator to travel from a first stimulating contact elastically fixed to a first region of the dorsal root nerve to a second stimulating contact elastically fixed to a second region of the dorsal root nerve. This induces a current within the dorsal root nerve along the path from the first region to the second region, causing depolarization of the axons within the nerve fibers in the form of a pulse signal. Preferably, the distance between the paired stimulating contacts changes the resistance by altering the path length of the current propagation between the first and second stimulating contacts. Preferably, the resistance between the paired stimulating contacts is less than the resistance from the stimulating contacts to the cerebrospinal fluid, and the resistance between the paired stimulating contacts is adjustable within a certain range (e.g., by changing the contact pressure and contact location) to optimize the propagation efficiency of the current within the dorsal root nerve. Specifically, the present invention preferably uses a flexible conductive material to make the stimulation contacts, and applies external force or voltage to deform the material, thereby changing the distance between the first stimulation contact and the second stimulation contact.

[0013] According to a preferred embodiment, a pair of stimulation contacts are used to provide pulsed stimulation signals to a group of nerve fibers within an inner perimysium, wherein the stimulation signal parameters of the stimulator for the pair of stimulation contacts are adjusted based on the electromyographic activity of the corresponding limb induced by the pulsed stimulation signals provided by this group of nerve fibers. Preferably, the contact resistance between the pair of stimulation contacts and the inner perimysium is less than the resistance from the stimulation contacts to the cerebrospinal fluid, ensuring that the current propagates primarily through the nerve fibers within the inner perimysium. Specifically, the pulsed stimulation signals provided by this group of nerve fibers can be transmitted to the posterior horn neurons of the spinal cord via the dorsal root nerves, and the posterior horn neurons transmit the signals to the anterior horn neurons via interneurons. The electrical activity transmitted by the anterior horn neurons through the anterior root of the spinal nerve induces electromyographic activity in the corresponding limb; or the pulsed stimulation signals directly stimulate the anterior root of the spinal nerve, inducing electromyographic activity in the corresponding limb. Further, the stimulation signal parameters of the stimulator for the pair of stimulation contacts are adjusted by recording the electromyographic activity.

[0014] According to a preferred embodiment, the stimulation electrode has stimulation contacts that are elastically fixed to the freed dorsal root nerve region by a C-shaped elastic arm that applies circumferential force. The stimulation electrode provides pulsed stimulation signals to a group of nerve fibers within the inner peritunic of the dorsal root nerve region via a conductive ring fixed to the stimulation contacts and facing the outer peritunic. The conductive ring is elastically wrapped by the C-shaped elastic arm radially outward of the dorsal root nerve, ensuring that the radially outward side of the conductive ring does not contact, or minimizes contact with, the cerebrospinal fluid within the dorsal root nerve region. Preferably, the contact resistance between the conductive ring and the inner peritunic of the dorsal root nerve is less than the resistance from the conductive ring to the cerebrospinal fluid.

[0015] According to a preferred embodiment, the C-shaped elastic arms for elastically fixing the stimulation contact are arranged in pairs, wherein a first elastic arm, a second elastic arm, and an opening / closing window are respectively provided along the length direction of the dorsal root nerve region in which they are located. The two elastic arms are used to elastically fix the stimulation contact with increased resistance, and the opening / closing window is used to engage clamps to open or close the two elastic arms.

[0016] The C-shaped flexible arm serves two main purposes: first, to hold the electrodes in place and prevent displacement; and second, to keep the conductive parts of the electrodes away from the cerebrospinal fluid, reducing signal loss or interference. In the cauda equina region, multiple electrodes are typically distributed within the cerebrospinal fluid. To allow for patient freedom of movement, these electrodes may be stimulated simultaneously, and sometimes increased current is needed to achieve therapeutic effects. This can lead to crosstalk between electrodes. Because each electrode holds a segment of the dorsal root nerve via the C-shaped flexible arm, forming a closed loop, and multiple such loops exist within the cerebrospinal fluid, induced currents may arise between these loops, a phenomenon that is difficult to predict and control.

[0017] The technical solution of this invention uses a C-shaped elastic arm to embrace the dorsal root nerve as much as possible, ensuring that the conductive ring has a large coverage area while isolating external cerebrospinal fluid from penetration. This design makes the resistance between the radially outer side of the C-shaped elastic arm and the cerebrospinal fluid greater than the resistance between the radially inner side of the C-shaped elastic arm and the outer perithelial membrane of the dorsal root nerve. As a result, most of the stimulation signal will be efficiently transmitted to the dorsal root nerve through the stimulation contact point, reducing signal loss and interference, and improving the accuracy and effectiveness of stimulation.

[0018] According to a preferred embodiment, the stimulator is configured to deliver an electrical stimulation signal to a selected stimulation electrode among a plurality of stimulation electrodes when connected to the selected stimulation electrode, the stimulator delivering at least one stimulation mode to the selected stimulation electrode.

[0019] The stimulator adjusts the frequency, pulse width, and intensity of the electrical stimulation signal according to the spatial location of the selected stimulating electrode on the cauda equina and the application time.

[0020] Preferably, the stimulator also adjusts the frequency, pulse width, and intensity of the electrical stimulation signal based on the resistance between the selected stimulation electrode and the cauda equina, to ensure that the current mainly propagates through the nerve fibers within the cauda equina, reducing the impact on non-target tissues.

[0021] Preferably, the stimulator further includes a time-series control module, which is capable of performing phased control of the stimulation mode of the selected stimulation electrode according to a preset time sequence.

[0022] According to a preferred embodiment, the waveform of the electrical stimulation signal applied by the stimulator includes a unilateral rectangular waveform, a unilateral pulse waveform, a unilateral triangular waveform, a unilateral sine waveform, a unilateral random waveform, a unilateral modulated waveform, a unilateral pulse train waveform, a unilateral linear rising and falling waveform, or a combination thereof. Preferably, the stimulator changes the waveform of the electrical stimulation signal by adjusting the resistance between the stimulating electrode and the cauda equina (e.g., by changing the contact pressure, contact location, and contact area), thereby reducing the impact of sudden current changes on the tissue.

[0023] According to a preferred embodiment, current from the stimulating electrode flows from the conductive loop of the isolated dorsal root nerve region into the outer peritunic of the dorsal root nerve. The stimulation of the current causes a change in the potential difference across the outer peritunic, resulting in depolarization of the outer peritunic. The current propagates into the dorsal root nerve to the peritunic of the nerve fiber, causing depolarization of the peritunic. The current continues to flow to the inner peritunic surrounding the nerve fiber, causing the action potential to be conducted along the axon.

[0024] According to a preferred embodiment, paired stimulation contacts are arranged on the dorsal root nerves floating in cerebrospinal fluid in the subarachnoid space.

[0025] According to a preferred embodiment, the stimulation contacts are designed to be connected to the electrode array of the stimulator in a unilateral or bilateral arrangement, depending on the nerve to be stimulated.

[0026] Preferably, the electrode array can selectively stimulate unilateral or bilateral spinal nerves of the same segment, as well as unilateral or bilateral spinal nerves of different segments. For example, it can stimulate the left and right sides or one side of the fourth lumbar nerve, the left and right sides or one side of the fifth lumbar nerve, the left and right sides or one side of the first sacral nerve, and the left and right sides or one side of the second sacral nerve.

[0027] A second aspect of the present invention provides a selective stimulation system, the system comprising:

[0028] A stimulator, which is used to generate electrical stimulation signals;

[0029] The stimulation electrode connected to the stimulator has a conductive ring with a C-shaped elastic arm that contacts the external perineurium of the spinal nerve.

[0030] A biosignal acquisition module, used to acquire electromyographic signals from the human body, and

[0031] The closed-loop controller is configured as follows:

[0032] The movement phases are divided in real time based on the spectral characteristics of electromyographic signals; the corresponding stimulation electrodes are activated according to a pre-stored movement pattern timetable; and the stimulation intensity ratio of different spinal nerve stimulation segments is dynamically adjusted based on body position sensor data. For example, the L2-S1 segment is adjusted.

[0033] According to a preferred embodiment, the closed-loop controller further includes a motion intention decoding unit that analyzes the time-frequency characteristics of electromyographic signals and stores several neural activation templates based on the patient's individualized basic movement patterns.

[0034] According to a preferred embodiment, each neural activation template corresponds to a specific spinal cord segment-muscle group innervation relationship. For example, template T1 (walking on flat ground - stance phase), target nerve roots: L4 (femoral nerve), S1 (tibial nerve); innervated muscle groups: quadriceps femoris (rectus femoris / vastus lateralis / vastus medialis), gastrocnemius-soleus complex.

[0035] According to a preferred embodiment, the closed-loop controller is configured to dynamically adjust stimulation parameters based on the patient's real-time motion status fed back by sensors, ensuring that the stimulation mode matches the patient's actual motion needs.

[0036] According to a preferred embodiment, the closed-loop controller is configured to control the intensity and duration of stimulation applied by the stimulator to the target spinal nerve root based on the limb motor function goals that the patient expects to achieve.

[0037] According to a preferred embodiment, the selective stimulation system further includes a motion capture module capable of adjusting the stimulation mode and parameters in real time based on muscle activity and feedback from synchronous motion sensors. Specifically, the system precisely aligns the motion capture data with the electrical stimulation pulses using timestamps to ensure that the stimulation activates the target muscle at the correct movement phase (such as the support or swing phase of gait).

[0038] A third aspect of the present invention provides a method for optimizing spinal nerve root stimulation parameters. This method is based on the stimulation system provided in the second aspect of the present invention. The method for optimizing spinal nerve root stimulation parameters includes the following steps:

[0039] Collect surface electromyographic signals of multiple muscle groups in the patient's limbs;

[0040] Extracting phase features of specific actions using convolutional neural networks;

[0041] Call the pre-stored motion pattern database to match the best neural activation sequence template;

[0042] Stimulation parameters are dynamically adjusted based on monitoring data.

[0043] The preferred limbs include the upper limbs and the lower limbs.

[0044] A fourth aspect of the present invention provides a selective stimulation system, particularly an implantable selective spinal nerve root stimulation system, comprising: a stimulator for generating an electrical stimulation signal having a frequency, pulse width, and intensity to induce motor commands in the affected limb of a patient; at least one stimulation electrode having stimulation contacts at its distal end; these stimulation electrodes extending cephalicly along the course of the spinal nerve, exiting from the dural sac region at the midline, passing through the interspinous space from the inside out through the skin, or directly connecting to the stimulator along a subcutaneous tunnel; the stimulation contacts of the stimulation electrodes are flexibly fixed to the freed spinal nerve region in a 270° circumferential manner, wherein the resistance from the stimulation contacts to the cerebrospinal fluid is greater than the resistance between the stimulation contacts and the cerebrospinal fluid. The resistance of the stimulation electrode is flexibly fixed between the outer perithelial membranes of the spinal nerve. The stimulation electrode is arranged in pairs with stimulation contacts. The stimulation contacts in the pairs are spaced apart. The spacing can create a signal loop between the pairs of stimulation contacts, so that the electrical stimulation signal provided by the stimulator can travel from the first stimulation contact flexibly fixed to the first region of the spinal nerve to the second stimulation contact flexibly fixed to the second region of the spinal nerve. In the path from the first region of the spinal nerve to the second region of the spinal nerve, the stimulation contacts of the stimulation electrode are elastically fixed to the free spinal nerve region by a C-shaped 270° flexible elastic arm in a circumferentially applied force.

[0045] According to a preferred embodiment, a pair of stimulation contacts are used to provide pulsed stimulation signals to a group of nerve fibers within an inner perithelial membrane, wherein closed-loop feedback is used to adjust the stimulation signal parameters of the stimulator for the pair of stimulation contacts based on the electromyographic activity of the corresponding limb induced by the pulsed stimulation signals provided by this group of nerve fibers.

[0046] According to a preferred embodiment, the stimulation electrode provides pulsed stimulation signals to a group of nerve fibers within the inner peritunic of the spinal nerve region via a conductive ring fixed to the stimulation contact and facing the spinal nerve region. The conductive ring is elastically wrapped by the C-shaped flexible elastic arm on the radially outer side of the spinal nerve to which it is fixed, so that the radially outer side of the conductive ring does not contact or minimizes contact with the cerebrospinal fluid within the spinal nerve region.

[0047] According to a preferred embodiment, the C-shaped flexible elastic arms for flexibly fixing the stimulation contact are arranged in pairs, wherein a first elastic arm, a second elastic arm, and an opening and closing window are respectively provided along the length direction of the spinal nerve region in which they are located. The two elastic arms are used to flexibly fix the stimulation contact with increased resistance, while the opening and closing window is used to engage the clamp to open or close the two elastic arms.

[0048] According to a preferred embodiment, the stimulator is configured to deliver an electrical stimulation signal to a selected stimulation electrode among a plurality of stimulation electrodes when connected to the selected stimulation electrode. The stimulator delivers at least one stimulation mode to the selected stimulation electrode, wherein the stimulator adjusts the frequency, pulse width, and intensity of the electrical stimulation signal according to the spatial location of the selected stimulation electrode on the spinal nerve and the application time. Preferably, the stimulator also adjusts the frequency, pulse width, and intensity of the electrical stimulation signal based on the resistance between the selected stimulation electrode and the spinal nerve. The stimulator further adjusts the frequency, pulse width, and intensity of the electrical stimulation signal based on the resistance between the selected stimulation electrode and the spinal nerve to ensure that the current propagates primarily through the nerve fibers within the spinal nerve, reducing the impact on non-target tissues. The stimulator further includes a time-series control module capable of performing phased control of different combinations of stimulation modes of the selected stimulation electrodes according to a preset time sequence, achieving regular sequential stimulation of relevant muscle groups to achieve a specific physiological movement, including but not limited to flexion and extension of the hip, knee, ankle, elbow, shoulder, and wrist joints, sitting up, lying down, standing, and walking. The stimulator changes the waveform and deformation rate of the electrical stimulation signal by adjusting the stimulation intensity between the stimulation electrode and the spinal nerve, thereby reducing the rigidity or spasm of the corresponding muscle group of the spinal nerve caused by sudden changes in current.

[0049] According to a preferred embodiment, current from the stimulating electrode flows from the conductive loop of the isolated spinal nerve region into the outer perineurium of the spinal nerve. The stimulation of the current causes a change in the potential difference across the outer perineurium, resulting in depolarization of the outer perineurium. The current propagates into the spinal nerve to the perineurium of the nerve fiber, causing depolarization of the perineurium. The current continues to flow to the inner perineurium surrounding the nerve fiber, causing the action potential to be conducted along the axon.

[0050] According to a preferred embodiment, pairs of stimulation contacts are arranged on spinal nerves floating in cerebrospinal fluid between the subarachnoid spaces.

[0051] The technical effects of this invention: Closed-loop spatiotemporal biomimetic stimulation (CSBS) is a dynamic neuromodulation technology based on real-time biosignal feedback. By simultaneously acquiring motor intentions (such as EEG, EMG, motion capture, etc.) and environmental information (such as gait phase and joint angles), it dynamically adjusts the timing, frequency, and intensity of the stimulator's pulses targeting specific spinal nerve root combinations, precisely simulating physiological motor rhythms and thus rapidly improving motor function. This invention uses the patient's motor intention as the initial driver, targeting and activating specific spinal motor neuron groups in time and space. First, the closed-loop spatiotemporal sequential biomimetic stimulation provided by this invention dynamically drives the adjustment of stimulation parameters through real-time acquired signals (such as EMG, motor intention, etc.), rather than relying on fixed programmed stimulation. Second, it simulates the timing of nerve impulse firing in healthy movement (e.g., the alternating activation of flexor and extensor muscles in the gait cycle). Third, it adjusts the stimulation strategy according to specific needs (such as climbing stairs, changes in sitting and standing posture, etc.). Specifically, this invention analyzes the activation patterns of spinal motor neurons in healthy individuals during exercise (such as the alternating activation of flexor and extensor muscles during walking) and uses CSBS to construct a precise spatiotemporal activation map. For example, during gait, L2-S1 segment neurons are activated in the sequence of "hip flexion → knee extension → ankle propulsion"; trunk control involves the activation of T12-L1 segment neurons, acting on the abdominal and quadratus lumborum muscles to maintain posture. These activation patterns are converted into pre-programmed stimulation sequences, allowing for the definition of electrode combinations, pulse frequencies (e.g., 20Hz for extensors, 100Hz for flexors), stimulation intensity, and duration for each motor phase. Attached Figure Description

[0052] Figure 1 is a schematic diagram of the direction of nerve conduction;

[0053] Figure 2 is a schematic diagram of the anatomy of the cauda equina and the location of electrode placement.

[0054] Figure 3 is a schematic diagram of the transverse anatomy of the spine and the location of electrode placement;

[0055] Figure 4 is a schematic diagram of the nerve anatomy and the elastic fixation of the stimulation contact points in a circumferential manner to the freed dorsal root nerve region.

[0056] Figure 5 is a schematic diagram of a C-shaped elastic arm fixed to the freed dorsal root nerve region;

[0057] Figure 6 is a schematic diagram of the stimulator and stimulating electrode according to a preferred embodiment;

[0058] Figure 7 is a schematic diagram of the stimulator and stimulating electrode according to another preferred embodiment;

[0059] Figure 8 is a schematic diagram of the structure of the stimulation contact point;

[0060] Figure 9 is a schematic diagram of the opening and closing window of the stimulation contact point;

[0061] Figure 10 is a schematic diagram of a clamp used to open or close two elastic arms;

[0062] Figure 11 is a waveform diagram of one embodiment of the stimulator;

[0063] Figure 12 is a waveform diagram of another implementation of the stimulator;

[0064] Figure 13 is a waveform diagram of another implementation of the stimulator;

[0065] Figure 14 is a schematic diagram of the selective stimulation system provided in Example 2 (partially referencing Wenger, N., et al. (2016). Spatiotemporal neuromodulation therapies engaging muscle synergies improve motor control after spinal cord injury. Nature Medicine, 22(2), 138–145.).

[0066] Figure 15 shows the leg muscle activity sequence of a healthy individual, the spatiotemporal map of motor neuron activation (motor hotspot map), and the spatiotemporal stimulation sequence template provided in Example 2 (refer to Rowald, A., et al. (2022). Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis. Nature Medicine, 28(2), 260–271.).

[0067] Figure 16 is a schematic diagram of the four stages of human walking and the electromyography (EMG) activity of related muscles provided in Example 2 (refer to Rowald, A., et al. (2022). Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis. Nature Medicine, 28(2), 260–271.).

[0068] List of reference numerals: 100: Stimulator; 110: Housing; 120: Lead wire interface; 130: Locking element; 200: Stimulating electrode; 210: Stimulating contact; 211: 212: Second stimulation contact; 220: Lead wire; 221: Insulating layer; 230: Conductive ring; 300: Dorsal root nerve; 310: First region; 320: Second region; 330: Posterior horn neuron; 340: Anterior horn neuron; 350: Efferent nerve; 360: Effector; 400: C-shaped elastic arm; 410: First elastic arm; 420: Second elastic arm; 430: Opening and closing window; 431: Inner edge of the section; 432: Outer edge of the section; 433: Inner flange of the window; 440: Connecting beam; 450: Opening and closing opening; 460: Opening flange; 470: Edge flange; 500: Clamp; 600: Spinal cord; 700: Cauda equina. Detailed Implementation

[0069] The following is a detailed explanation with reference to the accompanying drawings.

[0070] In this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In this invention, unless otherwise explicitly specified and limited, the terms "provided with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. It should be noted that the accompanying drawings disclosed in the following embodiments are for the purpose of explaining the technical features of the invention, and not for limiting its implementable forms.

[0071] The nerve fibers in the dorsal roots are sensory nerve fibers, which transmit sensory information from the outside world (such as touch, temperature, pain, etc.) to the central nervous system. For example, in the cauda equina 700, electrical stimulation signals are transmitted along the dorsal root fibers and enter the posterior horn of the spinal cord 600. The cauda equina 700 is composed of multiple spinal nerve roots, including the lumbar nerves (L1-L5) and sacral nerves (S1-S5). Each nerve root differentiates into posterior and anterior roots; the posterior roots are responsible for sensory information, while the anterior roots are responsible for motor signals.

[0072] In this invention, the midline refers to the central line of the body, and the spine extends along the midline.

[0073] Example 1

[0074] This embodiment provides an implantable selective spinal nerve root stimulation system, comprising a stimulator 100 and at least one stimulation electrode 200. The stimulator 100 of the implantable selective spinal nerve root stimulation system is an electronic device for generating electrical stimulation signals. The stimulator 100 can adjust the frequency, pulse width, and intensity of the electrical stimulation signals to promote motor commands in the affected limb of the patient. The stimulator 100 is preferably an electronic device with components such as a processor, memory, and output interface. The integrated design of the stimulator 100 combines the functions of stimulation signal generation and signal processing. The processor integrated within the stimulator 100 is responsible for generating, regulating, and managing the electrical stimulation signals. The electrical stimulation signals generated by the stimulator 100 to promote movement in the affected limb of the patient are realized through a built-in digital-to-analog converter (DAC). The memory is used to store stimulation parameters and preset programs. The output interface is used to connect to the stimulation electrode 200. The power supply of the stimulator 100 is preferably a built-in power supply (such as a rechargeable battery) to provide power to the entire device. The stimulator 100 can be configured with a wireless communication module (such as Bluetooth or Wi-Fi) to facilitate monitoring and control by external devices such as smartphones or computers. The stimulator 100 preferably has a built-in filter and regulator to ensure that the electrical signal transmitted from the stimulator 100 to the stimulation electrode 200 is within a preset range, thereby maximizing the stimulation effect.

[0075] The stimulator 100, which integrates a processor, is connected to the stimulation electrode 200 via leads 220, as shown in Figures 6 and 7. The stimulator 100 has a housing 110 to protect its internal electronic components from damage. The housing 110 is preferably flat and circular or rectangular. One side of the stimulator 100 has a lead interface 120. The lead interface 120 is used to connect the leads 220 of the stimulation electrode 200. The lead interface 120 is typically constructed as one or more slots. One slot preferably connects to one lead 220. The lead interface 120 transmits the electrical pulse signal generated by the stimulator 100 to the stimulation electrode 200 via the leads 220. The leads 220 are secured to the stimulator 100 by locking members 130. The leads 220 are used to transmit electrical signals emitted by the stimulator 100 to the stimulation electrode 200, allowing adjustment of the frequency, pulse width, and intensity of the electrical stimulation signal, thereby stimulating the target area. The lead 220 connecting the stimulator 100 and the stimulating electrode 200 is usually made of a conductive material, which has good conductivity, thereby reducing signal loss during transmission.

[0076] Lead 220 originates from lead interface 120 of stimulator 100 and enters the spinal region through skin puncture or surgical incision. Lead 220 extends along the epidural space of the spine, reaching the subarachnoid space of the lumbosacral or cervical segment. Lead 220 continues to extend until it reaches the area containing the cauda equina 700, brachial plexus, etc. The cauda equina 700 is an extension of the lumbosacral spinal cord and contains many nerve roots; the brachial plexus is a nerve root originating from the cervical enlargement of the spinal cord. Lead 220 extends cephalad along the course of the cauda equina 700 or brachial plexus, eventually reaching the position of stimulation electrode 200. Lead 220 is externally wrapped with an insulating layer 221, which may also be an insulating coating. The electrical signal is generated by the flow of current. When stimulator 100 emits an electrical signal, the signal generates a current in lead 220, which is transmitted along the length of lead 220 to stimulation contact 210. When current reaches the stimulating electrode 200, an electric field is created between the stimulating electrode 200 and the target tissue, causing ion flow and thereby triggering nerve or muscle excitation or contraction. The stimulating electrode 200 is preferably a conductive electrode with stimulating contacts 210.

[0077] The stimulating electrodes 200 extend cephalicly along the course of the cauda equina 700 or the brachial plexus. The stimulating electrodes 200 with stimulating contacts 210 emerge from the dural sac region at the midline, pass through the interspinous space from the inside out of the skin, or connect to the stimulator 100 via a subcutaneous tunnel and a lead 220. Preferably, several stimulating electrodes 200 with stimulating contacts 210 are arranged in parallel along the course of the cauda equina 700 or the brachial plexus, extending cephalicly, as shown in Figure 2. They emerge from the dural sac region at the midline, pass through the interspinous space from the inside out of the skin, or connect to the stimulator 100 via a subcutaneous tunnel and a lead 220. Specifically, several stimulating electrodes 200 with stimulating contacts 210 extend cephalicly along the course of the cauda equina 700 or the brachial plexus, wherein the stimulating electrodes 200 with stimulating contacts 210 are positioned between the dorsal root ganglion and the dorsal root nerve 300. The parallel stimulation electrodes 200 are anchored to the muscle fascia outside the interspinous space. The arrangement of several stimulation electrodes 200 is shown in Figure 2. The stimulation contacts 210 are arranged according to the nerve to be stimulated, and the lateral direction and nerve can be selected according to the condition. For example, the stimulation electrodes 200 can be arranged to stimulate both sides of the fourth lumbar nerve, but depending on the condition, only one side of the fourth lumbar nerve can be stimulated. The stimulation electrodes 200 can also be arranged to stimulate both sides of the fifth lumbar nerve, both sides of the first sacral nerve, or both sides of the second sacral nerve, or the cervical nerves innervating the brachial plexus. The stimulation electrodes 200 can also be arranged to stimulate both sides of the fourth lumbar nerve, both sides of the fifth lumbar nerve, both sides of the first sacral nerve, and both sides of the second sacral nerve. The placement of the stimulation electrodes 200 is shown in Figure 2.

[0078] The stimulation electrode 200 for transmitting electrical stimulation signals has stimulation contacts 210 at its distal end. The proximal end of the stimulation electrode 200 refers to the end connected to the stimulator 100 that generates the electrical stimulation signal via a lead 220. The distal end of the stimulation electrode 200 refers to the position close to the stimulation target (such as the dorsal root nerve 300). The stimulation electrode 200 is preferably equipped with one or more stimulation contacts 210 at its distal end. The stimulation contacts 210 are designed to be connected to the electrode array of the stimulator 100 in a unilateral or bilateral arrangement, depending on the nerve to be stimulated. The electrode array can stimulate the left and right sides or one side of the fourth lumbar nerve, the left and right sides or one side of the fifth lumbar nerve, the left and right sides or one side of the first sacral nerve, and the left and right sides or one side of the second sacral nerve. Depending on the patient's stimulation needs, either a unilateral arrangement of stimulation contacts 210 or a bilateral arrangement of stimulation contacts 210 can be selected. Specifically, a unilateral arrangement of stimulation contacts 210 means that the stimulation contacts 210 are arranged at a certain interval along one side of the lead wire 220. The unilateral arrangement of stimulation contacts 210 is mainly used to stimulate one side of the spinal cord 600. The specific number depends on the treatment needs; in this embodiment, the stimulation system may contain 4 to 16 contacts. Each stimulation contact 210 is connected to the lead wire interface 120 of the stimulator 100 via the lead wire 220. A bilateral arrangement of stimulation contacts 210 means that the lead wire 220 branches into a Y-shape at one point. The stimulation contacts 210 are arranged at a certain interval on the two arms of the Y-shaped lead wire 220. The bilateral arrangement of stimulation contacts 210 can simultaneously stimulate both sides of the spinal cord 600, typically containing 8 to 32 stimulation contacts 210, with 4 to 16 stimulation contacts 210 on each side.

[0079] The stimulation contact 210 is elastically fixed to the freed dorsal root nerve 300 region in a circumferential manner. The resistance of the stimulation contact 210 to the cerebrospinal fluid is greater than the resistance between the stimulation contact 210 and the outer pericardium of the dorsal root nerve 300, which is elastically fixed to it. The stimulation contact 210 located within the dural sac near the cerebrospinal fluid has an even greater resistance to the cerebrospinal fluid, meaning that the distribution of current flowing from the stimulation contact 210 to the cerebrospinal fluid is restricted, reducing the current intensity propagating through the cerebrospinal fluid and decreasing stimulation of surrounding non-target nerves. The resistance between the stimulation contact 210 and the outer pericardium of the dorsal root nerve 300 is smaller, allowing the current to concentrate in the area passing through the outer pericardium of the dorsal nerve, i.e., the contact area of ​​the nerve fibers. This resistance difference allows the current to be more effectively distributed to the target nerve region during stimulation, rather than spreading aimlessly. This technique ensures that the electrical stimulation signal generates clear and precise action potentials in the nerve, thereby improving the controllability of the therapeutic effect.

[0080] The stimulating electrode 200 extends from the lead interface 120 of the stimulator 100 and connects to the stimulating contact 210 of the dorsal root nerve 300. The electrical stimulation signal generated by the stimulator 100 is first processed by the processor, and the adjusted electrical stimulation signal is transmitted to the stimulating electrode 200 through the lead 220. The electrical stimulation signal from the proximal end of the stimulating electrode 200 is converted into an effective stimulation pulse at its distal end, and then applied to the stimulation target at the distal end through the stimulating contact 210.

[0081] The stimulating electrodes 200, extending cephalicly along the cauda equina 700, are preferably paired and equipped with stimulating contacts 210. These paired stimulating contacts 210, elastically fixed to the freed dorsal root nerve 300 in a circumferential manner, form a signal loop, ensuring continuous and stable current flow. The stability of this signal loop helps maintain the continuity and reliability of nerve stimulation. The stable signal loop reduces current attenuation during conduction, ensuring that the intensity of the stimulation signal does not significantly decrease with increasing propagation distance. Current from the stimulating electrodes 200 flows from the stimulating contacts 210 into the outer peritunic of the dorsal root nerve 300. The resistance between the stimulating contacts 210 and the elastically fixed outer peritunic of the dorsal root nerve 300 is much smaller than the resistance from the stimulating contacts 210 to the cerebrospinal fluid, thus allowing current to more easily enter the nerve fiber through this pathway. The path between the stimulation contact 210, with its lower resistance, and the outer periphery has less resistance, allowing current to be efficiently transmitted to the nerve fiber. The stimulation of the current causes a change in the potential difference across the outer periphery, resulting in outer periphery depolarization. This depolarization generates an electric field effect in the surrounding region, enhancing the membrane's effect on the underlying nerve fiber and propelling the current inward. The current reaches the periphery of the nerve fiber, causing its membrane potential to shift towards depolarization, i.e., the potential within the periphery increases (compared to the resting state). This change in the potential difference across the periphery due to depolarization propels the current further inward along the nerve fiber. The current flow in the periphery affects the inner periphery, causing the current to continue flowing towards the inner periphery surrounding the individual nerve fiber. Upon reaching the inner periphery, the current activates voltage-dependent sodium channels, leading to a rapid influx of sodium ions (Na+) into the cell, further triggering depolarization. When the potential within the inner periphery reaches a threshold, an action potential is triggered. The generated action potential propagates forward through the nerve fiber. The propagation of an action potential triggers the opening of sodium channels in the surrounding area through local depolarization, creating a "fluctuating" potential change. When the action potential reaches the nerve ending (presynaptic membrane), the potential change causes depolarization of the presynaptic membrane, prompting the opening of voltage-dependent calcium channels and the influx of calcium ions (Ca2+) into the presynaptic membrane. The influx of calcium ions triggers synaptic vesicle fusion with the membrane, releasing neurotransmitters (such as glutamate) into the synaptic cleft. The released neurotransmitters bind to receptors on the postsynaptic membrane, leading to depolarization of the postsynaptic membrane. When depolarization reaches a threshold, it can stimulate the postsynaptic anterior horn motor neurons in the spinal cord to generate new action potentials, which continue to transmit signals along the anterior root of the spinal nerve, acting on the target muscle group to produce muscle activity.

[0082] The stimulation electrode 200, extending cephalicly along the cauda equina 700, has paired stimulation contacts 210 spaced apart. The spacing between the paired stimulation contacts 210 is set such that the resistance between the two stimulation contacts 210 is less than the resistance between the stimulation contact 210 and the cerebrospinal fluid. The paired stimulation contacts 210 include a first stimulation contact 211 elastically fixed to a first region 310 of the dorsal root nerve 300, and a second stimulation contact 212 spaced apart from the first stimulation contact 211 along the length of the dorsal root nerve 300. This spacing enables a signal loop to be created between the paired stimulation contacts 210, allowing the electrical stimulation signal provided by the stimulator 100 to travel from the first stimulation contact 211, elastically fixed to the first region 310 of the dorsal root nerve 300, to the second stimulation contact 212, elastically fixed to the second region 320 of the dorsal root nerve 300, inducing a current within the dorsal root nerve 300 along the path from the first region 310 to the second region 320. This current causes depolarization of the axons within the nerve fiber in the form of a pulse signal. The first region 310 refers to a portion of the dorsal root nerve 300 where the first stimulation contact 211 is fixed. The second region 320 refers to another portion of the dorsal root nerve 300 spaced a certain distance from the first region 310, where the second stimulation contact 212 is fixed. The second region 320 receives the electrical signal conducted by the first stimulation contact 211 of the first region 310. The stimulator 100 sends an electrical stimulation signal in pulse form to the first stimulation contact 211 of the first region 310 of the dorsal root nerve 300. Upon receiving the electrical stimulation signal, the first stimulation contact 211 sends a current to the first region 310 of the dorsal root nerve 300 to activate the nerve fiber, thereby causing axon depolarization within the nerve fiber. The current generated by depolarization propagates along the nerve fiber, and the resulting electrical signal propagates along the axon within the nerve fiber, moving towards the second region 320. The current reaches the second region 320 of the dorsal root nerve 300, where the second stimulation contact 212 receives the pulse signal, further activating the nerve fiber in the second region 320. The current passing through the second stimulation contact 212 continues to propagate downstream to the neural structure, transmitting information to the central nervous system or other target areas, completing the transmission of the nerve signal. The paired arrangement of the stimulation contacts 210 forming the signal loop provides a more stable current distribution. The spacing between the paired stimulation contacts 210 allows for the formation of a more stable signal loop, ensuring that the flow of current in the nerve tissue is continuous and effective. When the stimulation contacts 210 are arranged in pairs and maintained at an appropriate distance, the current can simultaneously or alternately activate adjacent nerve fibers, producing a synchronization effect. This synchronization effect helps to accelerate the propagation of electrical signals in the nervous system and reduce signal conduction delay. The paired stimulation contacts 210 can also reduce the current intensity required to trigger depolarization by forming an interactive electric field.On the other hand, the paired stimulation contacts 210 allow for different stimulation patterns, such as alternating stimulation, synchronous stimulation, etc.

[0083] A pair of stimulation contacts 210 arranged at a certain interval on the dorsal root nerve 300 are used to provide pulse stimulation signals to a group of nerve fibers within the inner perineurium of a spinal nerve. The paired stimulation contacts 210 maintain a certain distance between them, for example, 1 mm. The implantable selective spinal nerve root stimulation system of this embodiment induces electromyographic activity in the corresponding limb based on the pulse stimulation signals provided by this group of nerve fibers. Specifically, the pulse stimulation signals provided by this group of nerve fibers are transmitted through the dorsal root nerve 300 to the posterior horn neurons 330 of the spinal cord. The posterior horn neurons 330 transmit the signals to the anterior horn neurons 340 through interneurons. The anterior horn neurons 340 induce electromyographic activity in the corresponding limb through the electrical activity transmitted by the anterior root of the spinal nerve. This setup uses feedback to adjust the stimulation signal parameters of the stimulator 100 for the pair of stimulation contacts 210 by recording the induced electromyographic activity of the corresponding limb. The stimulation signal parameters include, for example, the frequency, pulse width, and intensity of the electrical stimulation signal. Specifically, after incising the dura mater, the dorsal root nerve 300 is exposed by releasing the arachnoid adhesions. A 2-3 mm long portion of the dorsal root nerve 300 is "freed out" in the region between the dorsal root nerve 300's entry point into the spinal cord and the dorsal root ganglion. This freed portion of the dorsal root nerve 300 is used to fix the stimulation contact 210 of the stimulation electrode 200, as shown in Figures 3 and 4. The stimulator 100 applies an electrical stimulation signal to the stimulation electrode 200 fixed between the dorsal root ganglion of the afferent nerve and the dorsal root nerve 300. The stimulated region generates an electric field, causing depolarization of the dorsal root nerve 300. Depolarization leads to the formation of an action potential, which is conducted along the dorsal root nerve fibers. A group of nerve fibers within an inner perimysium can be subjected to a pulsed stimulation signal. The electrical stimulation signal enters the posterior horn region of the spinal cord from the dorsal root. The electrical signal is transmitted along the axon to the posterior horn neurons 330 in the posterior horn region, as shown in Figure 1. After passing through interneurons, it forms a bulge with the anterior horn neurons 340 (motor neurons), and is transmitted via the efferent nerve 350 (anterior root of the spinal nerve) to the effector 360 (such as skeletal muscle), thereby inducing skeletal muscle movement. Depolarization can be induced by applying pulsed stimulation signals (of various waveforms). For example, applying a +70mV electrical stimulation signal to a single nerve can cause Na+ in the nerve fiber to be induced because the applied electrical stimulation signal far exceeds the neuron's threshold (usually -55mV). + The passage opened quickly, Na +The action potential is generated by the stimulation of nerve cells, which causes a dramatic change in membrane potential. This action potential is transmitted along the axons within the nerve fibers (including sensory nerve fibers in the dorsal root) to the posterior horn neurons 330 of the spinal cord, then through interneurons, and finally through the anterior horn neurons 340, efferent nerves 350, and the anterior root of the spinal cord, to the skeletal muscles, thereby initiating skeletal muscle movement. Compared to direct stimulation of the anterior root of the spinal cord, the signal generated by stimulating the dorsal root nerve 300, after signal processing (synthesis) by the posterior horn neurons 330 and anterior horn neurons 340, produces a skeletal muscle movement signal that is more consistent with the natural movement state of the human body, thus simulating the voluntary movement pattern of a healthy human body. Specifically, the signal processed by the posterior horn neurons 330 and anterior horn neurons 340 through stimulation of the dorsal root nerve 300 follows the same path as the natural movement signal. The signal undergoes multi-level processing within the spinal cord 600, enabling better coordination of the movement of different muscle groups. This pathway exhibits high motor coordination and adaptability, mobilizing the intrinsic autonomic functions of the spinal cord and thus reducing unnecessary muscle spasms. Conversely, direct stimulation of the anterior root of the spinal nerve bypasses sensory processing and interneurons within the spinal cord 600°, directly causing muscle contraction. Because it skips the multi-level processing within the spinal cord 600°, the signal is directly transmitted to the target muscle. Lacking the regulation and integration of interneurons, muscle spasms may occur because the signal does not conform to the body's natural movement patterns. This pathway has low motor coordination and adaptability, thus lacking dynamic adjustment capabilities and easily leading to muscle spasms or over-contraction. In some extreme cases, such as when the dorsal root of the spinal nerve is damaged but the anterior root is normal, the system in this embodiment can directly stimulate the anterior root of the spinal nerve using specific parameters (such as narrow pulse width, high frequency, and low voltage) to induce movement of the target skeletal muscle.

[0084] The stimulation contact 210 of the stimulation electrode 200 is elastically fixed to the region of the freed dorsal root nerve 300 by a C-shaped elastic arm 400 in a circumferentially applied, encircling manner, as shown in Figures 4, 5, 8, and 9. The C-shaped elastic arm 400 is elastically fixed to the region of the freed dorsal root nerve 300 in such an encircling manner that the resistance between its radially outer side and the cerebrospinal fluid is greater than the resistance between its radially inner side and the outer perithelial membrane of the dorsal root nerve 300. This arrangement allows the stimulation signal to be efficiently transmitted to the dorsal root nerve 300 through the stimulation contact 210. The C-shaped elastic arm 400 refers to an elastic robotic arm with a C-shaped profile, whose curved portion can encircle or surround a target object. It is typically made of highly elastic materials (such as silicone, rubber, or other elastic polymers) and can deform under applied force without losing its original shape. The elasticity and fixing force of the C-shaped elastic arm 400 can be adjusted under specific conditions. Preferably, the radially outer side of the C-shaped elastic arm 400 is provided with an insulating coating to increase the resistance between the conductive ring 230 and the cerebrospinal fluid. Preferably, the resistance between the stimulation contact 210 and the outer perimeter of the dorsal root nerve 300 is changed by altering the contact area between the conductive ring 230 on the radially inner side of the C-shaped elastic arm 400 and the dorsal root nerve 300. Surface roughness affects the contact area; a larger contact area results in a smaller contact resistance. Increasing the contact area between the conductive ring 230 and the dorsal root nerve 300 can be achieved by using annular, mesh, or comb-shaped stimulation contacts 210. The roughness of the contact surface between the conductive ring 230 and the dorsal root nerve 300 is preferably designed to be much smaller than the roughness of the radially outer surface of the C-shaped elastic arm 400 in contact with the cerebrospinal fluid, thereby making the resistance from the stimulation contact 210 to the cerebrospinal fluid greater than the resistance between the stimulation contact 210 and the outer perimeter of the dorsal root nerve 300. Alternatively, conductive gel can be used to fill the tiny gaps between the conductive ring 230 and the dorsal root nerve 300, increasing the contact area and reducing the contact resistance. The conductive ring 230 is preferably made of a highly conductive material to significantly reduce the resistance of the stimulation contact 210 itself, so that the resistance between the stimulation contact 210 and its outer pericardium, which is elastically fixed to the dorsal root nerve 300, is significantly less than the resistance from the stimulation contact 210 to the cerebrospinal fluid.

[0085] As shown in Figure 4, the stimulation contact 210 has a certain width h in the longitudinal direction Z of the dorsal root nerve 300. The width h is set such that the resistance from the stimulation contact 210 to the cerebrospinal fluid is greater than the resistance between the stimulation contact 210 and its outer peritunic, which is elastically fixed to the dorsal root nerve 300. The width h is also set such that the contact area between the stimulation contact 210 and the outer peritunic is increased, thereby reducing the resistance between the stimulation contact 210 and its outer peritunic, which is elastically fixed to the dorsal root nerve 300. The width h is preferably in the range of 1 to 5 mm. According to one specific embodiment, the width h is approximately 1 mm. The stimulation contact 210 has a size in the circumferential direction C of the dorsal root nerve 300 that matches the diameter of the cauda equina 700, for example, approximately 1 mm. When the stimulation contact 210 encircles the dorsal root nerve 300, it applies a certain pressure to the dorsal root nerve 300 through its C-shaped elastic arm 400 to maintain itself within the dorsal root nerve 300. The stimulation contact 210 has an interface in the circumferential direction for fixing the stimulation electrode 200, which holds the electrode together with the stimulation contact 210, for example, by integral bonding or welding. Since the resistance from the radially lateral side of the C-shaped elastic arm 400 to the cerebrospinal fluid is greater than the resistance between the radially inner side of the C-shaped elastic arm 400 and the outer pericardium, most of the stimulation signal will be transmitted to the dorsal root nerve 300 via the stimulation contact 210. Specifically, the larger contact area between the radially inner side of the C-shaped elastic arm 400 and the outer pericardium reduces the resistance between the radially inner side of the C-shaped elastic arm 400 and the outer pericardium. On the other hand, the stimulation contact 210 of the stimulation electrode 200 is elastically fixed to the freed dorsal root nerve 300 region by the circumferentially applied force of the C-shaped elastic arm 400, resulting in a shorter distance between the stimulation contact 210 and the outer pericardium to which it is elastically fixed, thereby reducing the resistance between the stimulation contact 210 and the outer pericardium to which it is elastically fixed. The stimulation electrode 200 provides pulsed stimulation signals to a group of nerve fibers within the inner peritunic of the dorsal root nerve 300 via a conductive ring 230 fixed to the stimulation contact 210 and facing the region of the freed dorsal root nerve 300. The conductive ring 230 is elastically wrapped by a C-shaped elastic arm 400 radially outward of the dorsal root nerve 300, ensuring that the radially outward side of the conductive ring 230 does not contact, or minimizes contact with, the cerebrospinal fluid within the region of the dorsal root nerve 300. Specifically, the conductive ring 230 is positioned within the cavity of the C-shaped elastic arm 400 and closely adheres to its inner wall. The conductive ring 230 is tightly attached to the outer peritunic of the dorsal root nerve 300, while the C-shaped elastic arm 400 wraps around the radially outward side of the conductive ring 230, forming a protective layer and preventing displacement of the conductive ring 230. The C-shaped elastic arm 400 provides additional protection, reducing friction between the conductive ring 230 and surrounding tissues, thereby extending the electrode's lifespan. The conductive ring 230 and the C-shaped elastic arm 400 are aligned axially to ensure that the conductive ring 230 is effectively protected by the C-shaped elastic arm 400 as a whole.In addition, the elastic design of the C-shaped flexible arm 400 allows it to adapt to the slight movements of the dorsal root nerve 300 while maintaining the stable position of the conductive ring 230, thus reducing pressure on the nerve.

[0086] The C-shaped elastic arms 400 for elastically fixing the stimulation contact 210 are arranged in pairs. Each pair has a first elastic arm 410, a second elastic arm 420, and an opening / closing window 430 between the first and second elastic arms 420, along the length of the dorsal root nerve 300 region where it is located. These two elastic arms are used to elastically fix the stimulation contact 210 with increased resistance, while the opening / closing window 430 is used to engage the clamp 500 to open or close the two elastic arms, as shown in Figure 10. Specifically, the opening / closing window 430 has a connecting beam 440 on the tip of the C-shaped elastic arm 400, connecting the two elastic arms along the length of the dorsal root nerve 300 region. The ends of the first elastic arm 410 and the second elastic arm 420 away from the connecting beam 440 are not closed, forming a freely opening / closing opening 450, which allows the first elastic arm 410 and the second elastic arm 420 to open or close under the action of the clamp 500. The connecting beam 440 can be opened by the radially outward force of the jaws of the clamp 500 to surround the dorsal root nerve 300 and the corresponding conductive ring 230 of the stimulation contact 210 disposed thereon. When the clamp 500 releases the opening force, the first elastic arm 410 and the second elastic arm 420 can return to hold the conductive ring 230 under the restoring force of their elastic arms. When the first elastic arm 410 and the second elastic arm 420 rotate back to hold their respective conductive rings 230, the connecting beam 440 can act as the vertical axis of rotation of the first elastic arm 410 and the second elastic arm 420.

[0087] As shown in Figure 9, this invention features a C-shaped elastic arm 400 with a cylindrical structure, designed to achieve elastic fixation of the stimulation contact point 210. The C-shaped elastic arm 400 consists of a first elastic arm 410 and a second elastic arm 420 arranged opposite each other, connected by a connecting beam 440 located in the middle. The connecting beam 440 ensures that the first elastic arm 410 and the second elastic arm 420 are connected to each other at their ends furthest from each other. Both the first elastic arm 410 and the second elastic arm 420 are designed with an arc-shaped surface structure, preferably made of elastic materials such as silicone or medical-grade polyurethane. Under no external force, the two elastic arms have the same degree of curvature, ensuring that they can uniformly adhere to the dorsal root nerve 300 with the same elastic clamping force, forming a stable and uniform pressure distribution, and achieving a clasping fixation of the dorsal root nerve 300.

[0088] The ends of the first elastic arm 410 and the second elastic arm 420, away from the connecting beam 440, can be selectively closed or kept open depending on the diameter of the dorsal root nerve 300 to which they are fitted. When fitted onto a smaller diameter dorsal root nerve 300, the ends of the two elastic arms are in close contact to achieve natural closure; while when fitted onto a larger diameter dorsal root nerve 300, the two elastic arms are insufficient to achieve complete closure, so that an opening 450 is formed between their two ends.

[0089] On the inner wall of the C-shaped elastic arm 400, near both axial ends, there is at least one approximately circular conductive ring 230. Given the openable and closable characteristics of the first elastic arm 410 and the second elastic arm 420, the conductive ring 230 is designed to be in an open state at the openable and closable ends of the two elastic arms, and at least a certain gap is reserved to accommodate the fine adjustment changes in the shape of the two elastic arms.

[0090] The design of the C-shaped elastic arm 400 in this invention not only helps to fix the conductive ring 230 and prevent its displacement, but also effectively isolates the conductive ring 230 from the cerebrospinal fluid in the external environment. The two elastic arms elastically fix the stimulation contact 210 in a wrapping manner to increase the resistance between the stimulation contact 210 and the cerebrospinal fluid, reducing the attenuation or interference that may be encountered during the transmission of the stimulation signal. To this end, the axial ends of the C-shaped elastic arm 400 are fitted with flanges 470 to achieve effective isolation between the inside and the outside, especially to isolate the conductive ring 230 from the cerebrospinal fluid. The conductive ring 230 is not directly installed at the axial ends of the C-shaped elastic arm 400, but is left with a distance, so that the flanges 470 can fill this gap, further preventing cerebrospinal fluid from intruding into the internal space of the C-shaped elastic arm 400 from the axial direction. Meanwhile, viewed from the axial perspective of the C-shaped elastic arm 400, the flange 470 protrudes a certain thickness in the radial direction, which is greater than or at least equal to the thickness of the conductive ring 230, so as to ensure that the flange 470 can effectively protect the conductive ring 230 from the influence of the external environment from the axial direction.

[0091] The first elastic arm 410 and the second elastic arm 420 can form ports of a specific shape at the opening 450, which can perfectly align when the opening 450 is closed. This specific shape can be serrated, wavy, or other forms with similar structural features. Traditional planar contacts tend to lead to a large parallel-plate capacitor effect, resulting in high parasitic capacitance. In contrast, irregular structures (such as serrated or wavy shapes) effectively reduce parasitic capacitance by reducing the alignment of parallel surfaces between the two conductors. Furthermore, the design of irregular structures also plays an important role in reducing parasitic inductance. It makes the current flow path more tortuous, increasing the current path length. Simultaneously, this tortuous path design also helps to disrupt any potential closed loops in the magnetic field, reducing mutual inductance effects, thereby further reducing parasitic inductance and maximizing the effect of electrical stimulation.

[0092] The first elastic arm 410 and the second elastic arm 420 are equipped with an opening flange 460 extending axially along the C-shaped elastic arm 400 on the inner side of their ends near the opening 450. To prevent cerebrospinal fluid from seeping into the cylindrical space inside the C-shaped elastic arm 400 through the opening 450, the opening flange 460 is specifically designed to fill the gap between the conductive ring 230 and the irregularly shaped opening / closing ports of the two elastic arms, and extends axially along the C-shaped elastic arm 400 to match the profile of the irregularly shaped port. The opening flange 460 protrudes radially outward with a certain thickness, ensuring that this thickness is greater than or at least equal to the thickness of the conductive ring 230, thereby effectively protecting the conductive ring 230 circumferentially and preventing it from being affected by external environmental factors. This configuration ensures that when the C-shaped elastic arm 400 is elastically fixed to the freed dorsal root nerve 300 region in a circumferentially applied force-embracing manner, the resistance between the stimulation contact 210 and the outer pericardium of the dorsal root nerve 300 is much smaller than the resistance between the stimulation contact 210 and the cerebrospinal fluid.

[0093] The connecting beam 440, together with the first elastic arm 410 and the second elastic arm 420, aims to achieve complete or partial encirclement of the dorsal root nerve 300 region. The connecting beam 440 forms an opening / closing window 430 on its circumferential sidewall through partial resection, connecting the inner and outer spaces of the C-shaped elastic arm 400. Preferably, the shape and area of ​​the opening / closing window 430 are defined by four circumferential cross-sections, wherein the left and right cross-sections serve as boundary markers between the connecting beam 440 and the first elastic arm 410 or the second elastic arm 420, respectively; while the distance between the upper and lower cross-sections along the axial direction of the C-shaped elastic arm 400 is set with an upper limit to ensure that the conductive ring 230 is not exposed. The opening / closing window 430 is preferably designed as a regular rectangle, which facilitates the insertion of the clamp 500 tip, allowing the clamp 500 to open or close the first elastic arm 410 and the second elastic arm 420 by equal amount, and its regular edge design better adapts to the surface curvature of the dorsal root nerve 300, effectively reducing the risk of external cerebrospinal fluid infiltration.

[0094] Each cross-section of the opening / closing window 430 includes two boundaries: one is the inner edge 431 of the cross-section that is close to the surface of the dorsal root nerve 300, and the other is the outer edge 432 of the cross-section located on the circumference of the C-shaped elastic arm 400. To further improve the sealing performance of the edges of the opening / closing window 430, the area enclosed by the four inner edges 431 of the four cross-sections is designed to be larger than the area enclosed by the four outer edges 432. This means that in the upper cross-section of the opening / closing window 430, the height of the inner edge 431 of the cross-section located radially inward of the C-shaped elastic arm 400 is higher than the height of the outer edge 432 of the cross-section located radially outward; while in the lower cross-section of the opening / closing window 430, the height of the inner edge 431 of the cross-section located radially inward is lower than the height of the outer edge 432 of the cross-section located radially outward. In addition, the included angle formed between the left or right cross-section of the opening / closing window 430 and the circumference of the C-shaped elastic arm 400 is preferably an acute angle. Viewed radially, the opening / closing window 430 exhibits a constricted structure that gradually narrows from the inside out across its four cross-sections. Conversely, viewed from the (possible) direction of cerebrospinal fluid infiltration, the opening / closing window 430 has its smallest cross-section on the circumferential surface of the C-shaped elastic arm 400, and its cross-section gradually increases as cerebrospinal fluid gradually infiltrates inward. According to Bernoulli's principle, when cerebrospinal fluid flows in the constricted region, its flow velocity increases, and this increase in velocity is accompanied by a decrease in pressure. In the constricted structure of the opening and closing window 430, the cerebrospinal fluid first passes through the narrowest part (i.e., the smallest cross-section formed by the four outer edges 432 of the opening and closing window 430), and then enters a larger space (i.e., the area between the smallest cross-section and the largest cross-section formed by the four inner edges 431 of the cross-section). This design allows the cerebrospinal fluid to be rapidly accelerated when flowing through the smallest cross-section of the opening and closing window 430, resulting in a rapid decrease in pressure entering this space. External cerebrospinal fluid is less likely to seep into the interior through the opening and closing window 430, thereby enhancing the anti-permeability capability. Ultimately, the resistance from the stimulation contact 210 to the cerebrospinal fluid is greater than the resistance between the stimulation contact 210 and its outer perimeter membrane, which is elastically fixed to the dorsal root nerve 300.

[0095] Preferably, the inner edges 431 of all four cross-sections of the opening and closing window 430 are provided with inner flanges 433 to further enhance the ability to prevent cerebrospinal fluid penetration. Specifically, the inner flanges 433 of the left and right cross-sections of the opening and closing window 430 can extend to a certain width along the circumference of the inner wall of the connecting beam 440; the inner flanges 433 of the upper and lower cross-sections of the opening and closing window 430 extend to a certain width along the axial direction of the inner wall of the connecting beam 440.

[0096] The stimulator 100 is configured to deliver an electrical stimulation signal to a selected stimulation electrode 200 among the plurality of stimulation electrodes 200 when connected to the selected stimulation electrode 200. The stimulator 100 delivers at least one stimulation mode to the selected stimulation electrode 200, wherein the stimulator 100 adjusts the frequency, pulse width, and intensity of the electrical stimulation signal according to the spatial location of the selected stimulation electrode 200 on the cauda equina 700 and the application time. Preferably, the stimulator 100 further includes a time sequence control module capable of performing staged control of the stimulation mode of the selected stimulation electrode 200 according to a preset time sequence. Preferably, the stimulation mode delivered by the stimulator 100 to the selected stimulation electrode 200 includes one or more of a single-pulse mode, a continuous-pulse mode, an alternating-pulse mode, and a modulated-pulse mode. For example, during surgery, clamps 500 are used to open the C-shaped elastic arm 400 through the opening and closing window 430, and the conductive ring 230 is fixed to the outer perithelial membrane of the dorsal root nerve 300. This embodiment uses electrical stimulation at specific locations on the cauda equina 700 (L4-L5 and S1-S2 segments) as an example. For the L4-L5 segment, a continuous pulse mode is selected with a frequency of 20Hz, a pulse width of 200μs, and an initial intensity of 0.5mA. For the S1-S2 segment, a modulated pulse mode is selected, with the frequency gradually increasing from 20Hz to 30Hz, a pulse width of 200μs, and an initial intensity of 0.5mA. The intensity is gradually adjusted according to the patient's tolerance and treatment effect. For example, the initial intensity can be set to 0.5mA and gradually increased to 1.0mA based on patient feedback.

[0097] The waveform of the electrical stimulation signal applied by the stimulator 100 includes unilateral rectangular waveforms, unilateral pulse waveforms, unilateral triangular waveforms, unilateral sine waveforms, unilateral random waveforms, unilateral modulated waveforms, unilateral pulse train waveforms, unilateral linear rising and falling waveforms, or combinations thereof. Furthermore, another innovation of this embodiment is the use of different stimulation waveforms related to duration to selectively stimulate specific nerve roots at different time intervals within a single action cycle, inducing sequential muscle activity and achieving specific movements. Waveform examples provided in this embodiment are shown in Figures 11 to 13.

[0098] The current from the stimulating electrode 200 flows from the conductive ring 230 of the separated dorsal root nerve 300 region into the outer periphery of the dorsal root nerve 300. The stimulation of the current causes a change in the potential difference between the inside and outside of the outer periphery, which causes the outer periphery to depolarize. The current propagates into the dorsal root nerve 300 to the periphery of the nerve fiber, causing the periphery to depolarize. The current continues to flow to the inner periphery surrounding the nerve fiber, which causes the action potential to be conducted along the axon.

[0099] Pairs of stimulation contacts 210 are positioned on the dorsal root nerve 300, which floats in the cerebrospinal fluid within the subarachnoid space. The paired stimulation contacts 210 provide independent current channels with low or negligible resistance between the stimulation contacts 210 and the outer perimeter of the dorsal root nerve 300, thus reducing the likelihood of current flowing through the cerebrospinal fluid. Preferably, the stimulator 100 can adjust the number, arrangement, and order of application of the electrical stimulation signals according to the patient's condition. For example, for the L4-L5 segment, one stimulation electrode 200 is used, with four stimulation contacts 210 arranged unilaterally along the outer perimeter of the dorsal root nerve 300; for the S1-S2 segment, one stimulation electrode 200 is used, with four stimulation contacts 210 arranged bilaterally along the outer perimeter of the dorsal root nerve 300. The order of application of the electrical stimulation signals is as follows:

[0100] Initial Phase: L4-L5 segments: Activated first using a continuous pulse pattern with a frequency of 20Hz, a pulse width of 200μs, an initial intensity of 0.5mA, and a duration of 200ms, aiming to generate a 200ms sustained dorsiflexion movement. S1-S2 segments: Activated subsequently using a modulated pulse pattern with a frequency gradually increasing from 20Hz to 30Hz, a pulse width of 200μs, an initial intensity of 0.5mA, and a duration of 300ms, aiming to generate a 300ms sustained plantarflexion movement. Through the above sequential stimulation, the goal is to complete a full set of dorsiflexion and plantarflexion movements within 500ms.

[0101] Mid-term adjustments: L4-L5 segment: maintain 20Hz and 0.5mA; if the patient's dorsiflexion strength recovery is limited, the frequency can be increased to 30Hz and the intensity to 1.0mA. Similarly, 200ms after L4-L5 stimulation, subsequent stimulation of S1-S2 segment: adjust the frequency range to 20Hz to 40Hz and increase the intensity to 1.0mA.

[0102] Post-treatment optimization: Based on patient feedback and treatment results, further optimize the stimulation mode and parameters.

[0103] The temporal stimulation effects of this invention are not limited to the ankle joint activities described above. Similar stimulation can be used to achieve wrist, elbow, shoulder, hip, and knee joint activities. By combining the aforementioned stimulation parameters in different ways, coordinated multi-joint activities of the upper or lower limbs can be accomplished. In addition, continuous baseline stimulation can maintain muscle tone, thereby maintaining fixed positions such as sitting, lying on one's side, and standing.

[0104] Example 2

[0105] This embodiment provides a selective stimulation system that achieves stimulation through selective sequential spinal nerve stimulation. The selective stimulation system provided in this embodiment adds a closed-loop spatiotemporal sequential biomimetic stimulation operation to the system described in Embodiment 1; details will not be repeated here.

[0106] According to this embodiment, the selective stimulation system includes a stimulator 100, a stimulation electrode 200, a biosignal acquisition module, and a closed-loop controller. The stimulator 100 preferably includes a programmable pulse generator and a multi-channel switching module. The conductive ring 230 of the C-shaped elastic arm 400 of the stimulation electrode 200 contacts the outer periphery. The biosignal acquisition module preferably includes a surface electromyography (EMG) sensor and an implanted neural signal electrode. The closed-loop controller is configured to: real-time segment the motor phase based on the spectral characteristics of the EMG signal; activate the corresponding stimulation electrode 200 according to a pre-stored motor pattern timing table; and dynamically adjust the stimulation intensity ratio of the L2-S1 segments based on body position sensor data. The closed-loop controller preferably also includes: a motor intention decoding unit, which uses a CNN network to analyze the time-frequency characteristics of the surface EMG signal; and a timing reconstruction unit, which stores neural activation templates for several basic motor patterns.

[0107] The stimulator 100 incorporates a closed-loop system. The selective stimulation system provided in this embodiment utilizes positive electromyographic feedback to cater to patients with spinal cord injury and weak lower limb motor function (grade 1-2 muscle strength). Specifically, for a specific patient group with high-level spinal cord injury and weak voluntary electromyographic activity in the lower limbs, this system innovatively features a set of patch Bluetooth electromyographic sensors applied to the surface of the major muscle groups of the lower limbs. These sensors are made of thin, soft, and biocompatible materials, allowing them to closely adhere to the muscle surface and, without affecting the patient's normal muscle activity, to acquire weak electrical signals generated by muscle contraction and relaxation in real time with high sensitivity. The signal acquisition frequency and accuracy have been rigorously calibrated and optimized. The acquired electromyographic signals are transmitted to the stimulator 100 via stable and efficient Bluetooth wireless transmission technology. The stimulator 100's built-in intelligent analysis module uses pre-built algorithms to analyze key features such as signal strength, frequency, and waveform, accurately locating the muscle groups that currently require enhanced stimulation. The stimulation command is then immediately fed back to the corresponding stimulation electrode 200, triggering a new round of contraction in the muscle group. This cycle repeats, forming a virtuous positive feedback loop. Under the continuous action of this closed-loop system, the patient's weak voluntary electromyographic activity, aided by precise stimulation, gradually restores and strengthens the voluntary movement ability of the lower limb muscles. Its principle is similar to that of a steering wheel or brake assist system.

[0108] The selective stimulation system provided in this embodiment can also be adapted to patients with complete high spinal cord injury and no lower limb electromyographic activity via an EEG signal analysis interface. Specifically, the stimulator 100 hardware architecture has a dedicated interface that uses a high-speed, high-stability data transmission protocol to ensure rapid and accurate data exchange between the EEG signal acquisition and analysis equipment and the stimulator 100 in the future. Built-in signal-to-analog conversion and signal conditioning technologies can convert EEG signals of different formats, frequency bands, and amplitudes into instruction formats that the stimulator 100 control system can accurately recognize and process. Built-in intelligent filtering and noise reduction algorithms perform preliminary screening and purification of the raw EEG signals, removing interference noise and extracting effective signals, ensuring that the accessed EEG signals have high accuracy and usability, laying the foundation for future deep integration with EEG technology.

[0109] Preferably, the stimulation system provided in this embodiment also includes a speech recognition system, which is preferably integrated into a wireless controller and has a built-in high-sensitivity microphone. This configuration reduces the interference of environmental noise on the speech signal, ensuring that the acquired speech signal is clear and accurate. The microphone collects the patient's speech commands and then matches them with preset patient speech commands (using an encrypted speech recognition algorithm specific to the individual to avoid malicious or non-malicious commands from others). The stimulation program preset in the stimulator 100 is then activated via a wireless module. Given the current difficulty in extracting EEG features, recognizing speech commands is an effective way to enable the system on demand.

[0110] The closed-loop system built into the stimulator 100 in this embodiment is shown in Figure 14, and its implementation is as follows:

[0111] S1: Sensor Data Acquisition and Analysis. Real-time collection of various sensor data from the patient's lower limbs, such as electromyography (EMG) sensors monitoring muscle activity, force sensors detecting limb force, and position sensors detecting limb spatial position and velocity. This data is analyzed to extract key features, such as the intensity and duration of muscle contractions, as well as the magnitude and distribution of limb force. For example, by analyzing the amplitude and frequency of EMG signals, it can be determined whether the muscles are in a state of over-fatigue or insufficient activation. Upon receiving a positional change signal from the gyroscope, the system immediately switches to the preset stimulation mode for the corresponding position based on a pre-built position-stimulation pattern database. When the patient sits up, the stimulation mode quickly activates to adapt to the sitting posture, precisely controlling the stimulation of the relevant spinal nerve roots to ensure that the lower limb muscles are appropriately relaxed and maintain a comfortable sitting posture. When standing, it immediately and seamlessly switches to the support and stability stimulation mode to strengthen the support of the lower limb muscles and prevent falls due to instability. When walking and turning, it quickly adjusts to the flexible turning stimulation mode to coordinate the coordinated turning movements of the lower limb muscle groups, ensuring that the stimulation is precisely matched with the patient's real-time movements. This comprehensively eliminates stimulation failure or discomfort that may be caused by changes in body position, significantly improving the safety and comfort of patients in daily use.

[0112] S2: Feedback-based parameter adjustment. Based on the sensor data analysis results, the software algorithm automatically adjusts the stimulation parameters. If the electromyographic signal shows that a certain muscle is over-fatigued, the algorithm reduces the stimulation intensity of the corresponding nerve root or extends the stimulation interval; if the force sensor detects uneven force on the limb, the algorithm adjusts the stimulation sequence or duration of the relevant nerve roots to improve limb balance and motor coordination.

[0113] S3: Setup of the Biosignal Acquisition Module. The biosignal acquisition module is preferably configured as a surface Bluetooth wireless electromyography (EMG) acquisition module. This module includes a high-precision sensor array and a signal preprocessing unit. The high-precision sensor array employs an array-type EMG sensor layout, using highly sensitive, low-noise electrode materials such as silver chloride electrodes. These electrodes fit closely to the skin surface of the patient's lower limbs, capturing weak spontaneous EMG signals and ensuring accurate and comprehensive signal acquisition, capturing no subtle changes in muscle electrical activity. The signal preprocessing unit, integrated within the biosignal acquisition module, performs preliminary amplification and filtering on the acquired raw EMG signals. It removes environmental noise, power frequency interference, and physiological noise from the body itself, such as ECG signal interference, extracting pure EMG signal characteristics to provide a high-quality input signal for subsequent positive feedback amplification.

[0114] S4: Bluetooth wireless transmission module setup. A low-power, high-stability Bluetooth chip is selected to achieve wireless data transmission between the acquisition module and the implantable stimulator 100. Data is encapsulated and transmitted according to the Bluetooth standard protocol to ensure fast and accurate transmission, and the processed electromyographic signals are fed back to the stimulator 100 in real time to achieve closed-loop control information interaction.

[0115] S5: Setting up external control and monitoring equipment. External control is achieved through a programmable terminal. Portable programmable terminals are preferred, such as tablets or smartphone applications, allowing doctors and patients to operate them through an intuitive graphical interface. The terminal displays real-time electromyographic (EMG) signal data, the stimulator's operating status, and pre-set stimulation program parameters. It also facilitates adjustments to stimulation parameters and program switching, enabling remote control of the entire system. The programmable terminal has a built-in large-capacity storage function to record long-term EMG data and treatment process information, facilitating subsequent review and analysis of the patient's rehabilitation progress. Built-in data analysis algorithms are used to mine the accumulated data, such as comparing EMG signal trends over different time periods, evaluating rehabilitation effects, and providing a basis for further optimization of the stimulation program.

[0116] The implementation steps of the selective stimulation system in this embodiment are as follows:

[0117] S1: Data collection and individualized patient information entry;

[0118] S2: Stimulation parameter initialization settings;

[0119] S3: Sequential stimulus logic implementation;

[0120] S4: Algorithm storage and user interface interaction.

[0121] According to this embodiment, data collection and individualized patient information entry include the following operations:

[0122] Obtaining basic patient information: A patient information database is created within the software system, recording the patient's basic physical data, such as age, height, weight, and body mass index (BMI). This information provides a basic reference for subsequently determining the appropriate range of stimulus intensity. For example, younger and more physically robust patients may be able to tolerate relatively higher intensity stimuli.

[0123] Obtain neurological function assessment data: Import data on the functional status of spinal nerve roots in the lumbosacral region or cervical enlargement area obtained through neurophysiological examinations (such as electromyography, nerve conduction velocity testing, etc.). Identify which nerve roots retain some function and which nerve roots are more severely damaged, and use this as a basis to plan stimulation strategies for different nerve roots. For example, for nerve roots with better functional preservation, a relatively low initial stimulation intensity can be set.

[0124] Obtaining a motor function needs assessment: Thoroughly communicate with the patient to understand their desired level of motor function recovery, such as whether they only wish to stand or further aspire to perform complex movements like walking. Analyze the patient's daily activity scenarios to determine the specific requirements for lower limb muscle strength and motor coordination under different motor tasks. For example, if the patient wishes to walk short distances indoors, the software algorithm should focus on optimizing the stimulation programs related to stepping and balance.

[0125] According to this embodiment, the initialization setting of stimulation parameters includes the following operations:

[0126] Setting the stimulation intensity: Based on the patient's neurological function and physical condition, set the initial stimulation intensity for each spinal nerve root to be stimulated. Generally, start with a lower intensity to avoid overstimulating the nerve. For example, for patients receiving stimulation for the first time, the initial stimulation intensity can be set to a threshold level that can elicit a slight muscle contraction response, and then gradually adjusted based on patient feedback and actual movement effects.

[0127] Setting the stimulation duration: For nerve roots corresponding to different motor functions, set the initial stimulation duration. For example, in standing movements, the nerve root that maintains the contraction of the leg extensor muscles can be stimulated for a relatively long and stable duration; while in walking movements, the nerve root responsible for leg swinging needs to be dynamically adjusted according to the walking rhythm. Initial settings can refer to the contraction time patterns of the corresponding muscles during normal human movement, and fine-tuned based on the patient's actual situation.

[0128] Stimulation sequence is set: Based on the anatomical and physiological principles of lower limb movement, the initial sequence of nerve root stimulation is determined. For example, in the standing preparation phase, the nerve roots responsible for stabilizing the pelvis and hip joint are stimulated first, followed by the nerve roots controlling the extension of the knee and ankle joints in sequence. The software algorithm records these nerve root stimulation sequences in the form of an ordered list to ensure the coordination of movement, as shown in Figure 15. Figure a shows the electromyographic activity of different leg muscles, such as the rectus femoris (RF), vastus lateralis (VLat), semitendinosus (ST), tibialis anterior (TA), and soleus (Sol), in a healthy individual during the standing and swinging phases. The vertical axis represents the amplitude of the electromyographic signal (0.5mV), and the horizontal axis represents time (1s). Figure b is a spatiotemporal diagram of motor neuron activation, marking the posture and swinging phases, as well as different nerve root levels (L1-L5, S1-S2). Different colors and outlines in the figure represent different motor function areas, such as weight acceptance, propulsion, and flexion. Figure c is a spatiotemporal stimulus sequence template, showing the stimulation sequence of the left and right legs during the standing and swinging phases, with different colored squares and numbers 1-4 indicating the order of stimulation.

[0129] According to this embodiment, the sequential stimulus logic implementation steps are as follows:

[0130] (1) State Machine Model Construction: A state machine model is used to describe the transitions between different lower limb movement states. Various movement states are defined, such as standing, preparing to step, stepping, support phase, and swinging phase. Each state corresponds to a specific set of nerve root stimulation parameters. For example, in the standing state, the stimulation electrode 200 continuously stimulates the lumbosacral spinal nerve roots responsible for maintaining leg extension and body balance at a specific intensity and duration; when entering the preparing to step state, the state machine triggers the corresponding program, adjusting the stimulation parameters so that the nerve roots responsible for leg lifting begin to receive stimulation sequentially. The four phases of human walking include hip flexion, full leg flexion, weight-bearing phase, and propulsion phase. Figure 16 shows the four phases of human walking and the electromyographic (EMG) activity and stimulation methods of the related muscles. The muscles involved in hip flexion include the iliopsoas (Il), rectus femoris (RF), vastus lateralis (VLat), semitendinosus (ST), tibialis anterior (TA), gastrocnemius (MG), and soleus (Sol). The most important of these is the iliopsoas, which is divided into the psoas major and iliacus. The psoas major is mainly innervated by the anterior branches of the 2nd and 3rd lumbar nerves, while the iliacus is mainly innervated by the anterior branches of the 1st, 2nd, and 3rd lumbar nerves. The electromyography (EMG) frequency is 100 Hz, and the waveforms in the figure illustrate the electrical activity of these muscles during this phase. Therefore, in this embodiment, hip flexion primarily stimulates the L2 and L3 spinal nerves. The muscles involved in full leg flexion are similar to those in the first stage, including the iliopsoas, rectus femoris, vastus lateralis, semitendinosus, tibialis anterior, gastrocnemius, and soleus. The iliopsoas is the most important, primarily innervated by the L2-L3 spinal nerves. The electromyography (EMG) frequency is also 100Hz, and the waveforms of different muscle electrical activity reflect their working state during full leg flexion. The weight-bearing stage mainly involves the vastus lateralis, rectus femoris, semitendinosus, tibialis anterior, gastrocnemius, and soleus. The vastus lateralis, gastrocnemius, and soleus are the most important in this stage, primarily innervated by the L2-L4 spinal nerves. The EMG frequency drops to 20Hz in this stage, and the waveforms show the changes in electrical activity of each muscle under body weight. The propulsion stage involves the semitendinosus, gastrocnemius, soleus, rectus femoris, vastus lateralis, and tibialis anterior. The gastrocnemius and soleus are the most important in this stage, primarily innervated by the tibial nerve (anterior branches of the S1-S2 spinal nerves). The electromyography (EMG) frequency is 20 Hz, and the EMG waveform at this stage shows how these muscles work together to propel the body forward.

[0131] (2) Timing Control: Within each movement state, the start and end times of stimulation of different nerve roots are precisely controlled according to the timing requirements of the movement. For example, during stepping, the nerve root that flexes the hip joint is stimulated first, and after a short delay, the nerve roots that flex the knee joint and dorsiflex the ankle joint are stimulated sequentially to simulate normal stepping movements. By setting precise time intervals, the stimulation of each nerve root is ensured to be coordinated in time to achieve smooth movement. To achieve precise reconstruction of lower limb motor function, multiple sets of specially designed stimulation electrodes 200 are rationally arranged and precisely connected to different lumbosacral spinal nerve roots. This connection arrangement is not arbitrary, but based on in-depth research on the anatomy, physiology, and biomechanics of the human lower limb nerves. Based on the lower limb motor function goals that patients expect to achieve, covering the needs of different stages from the most basic static standing to maintain body balance, to gradually bearing body weight to achieve weight-bearing forward, to taking steady steps and walking smoothly and naturally, a series of closely related stimulation program groups have been programmed. Each program set is like a precise "neural instruction set," which can accurately control the intensity of stimulation applied to each spinal nerve root, simulate the strong and weak changes of the human body's natural nerve impulses, and precisely set the stimulation duration to ensure that each stimulation can perfectly match the contraction and relaxation rhythm of the lower limb muscles, thereby driving the lower limb muscle groups to move in a coordinated and efficient manner, and gradually reshaping the patient's lower limb movement pattern.

[0132] (3) Condition Judgment and Transition: Set state transition conditions for the state machine. These conditions are based on sensor feedback data (such as changes in plantar pressure detected by the pressure sensor, acceleration of limb movement detected by the accelerometer, etc.) and preset motion targets. For example, when the plantar pressure sensor detects that the pressure on one side of the foot has decreased to a certain extent, and the accelerometer detects that the leg has a tendency to swing forward, the state machine determines that the stepping condition is met, transitions from the standing state to the stepping state, and adjusts the nerve root stimulation program accordingly.

[0133] According to this embodiment, the steps for algorithm storage and user interface interaction are as follows:

[0134] Algorithm storage and management: Individualized sequential stimulation algorithms generated for each patient are stored in a database, including essential lower limb movements in daily life (sitting → standing; lying down → sitting up; maintaining a standing position; alternating steps on flat ground; going upstairs; going downstairs; going uphill; going downhill, etc.). A unique patient identifier is established to correspond with the algorithm data. The algorithm data is backed up regularly to prevent data loss and facilitate subsequent review and analysis of the patient's treatment process.

[0135] User Interface Design: A simple and intuitive user interface was developed for doctors and patients. Doctors can view detailed patient information, current stimulation parameters, and real-time sensor feedback data on the interface, and manually adjust algorithm parameters as needed. Patients can use the interface to report their movement sensations and discomfort, such as muscle pain and the smoothness of movement. The interface also provides operation guides and help documentation to facilitate user experience with the software system.

Claims

1. A stimulating electrode, characterized in that The stimulating electrodes (200) are arranged in pairs with stimulating contacts (210). Among them, the paired stimulation contacts (210) maintain a certain distance between them. The spacing enables a signal loop to be generated between the paired stimulation contacts (210), allowing the electrical stimulation signal provided by the stimulator (100) to travel from the first stimulation contact (211) in the first region (310) of the dorsal root nerve (300) to the second stimulation contact (212) in the second region (320) of the dorsal root nerve (300). Initiate an electric current within the dorsal root nerve (300) along the pathway from the first region (310) of the dorsal root nerve (300) to the second region (320) of the dorsal root nerve (300).

2. The stimulating electrode according to claim 1, characterized in that The stimulation contacts (210) of the stimulation electrode (200) are elastically fixed to the freed dorsal root nerve (300) region by a C-shaped elastic arm (400) in a circumferentially applied force-encircling manner.

3. The stimulating electrode according to claim 1, characterized in that The current is in the form of a pulse signal that causes depolarization of the axons within the nerve fiber.

4. The stimulating electrode of claim 1, wherein A pair of stimulation contacts (210) are used to provide pulsed stimulation signals to a group of nerve fibers within an inner perithelial membrane, wherein the stimulation signal parameters of the stimulator (100) for the pair of stimulation contacts (210) are adjusted according to the electromyographic activity of the corresponding limb induced by the pulsed stimulation signals provided by this group of nerve fibers.

5. The stimulating electrode according to claim 1 or 4, characterized in that The stimulation electrode (200) provides pulsed stimulation signals to a group of nerve fibers within the inner peritunic via a conductive ring (230) of the outer peritunic fixed to the stimulation contact (210) and facing the region of the freed dorsal root nerve (300). The conductive ring (230) is elastically wrapped by the C-shaped elastic arm (400) on the radially outer side of the dorsal root nerve (300) that fixes it, so that the radially outer side of the conductive ring (230) does not contact or minimizes contact with the cerebrospinal fluid in the area of ​​the dorsal root nerve (300).

6. The stimulating electrode according to claim 1 or 2, characterized in that The C-shaped elastic arms (400) for elastically fixing the stimulation contact (210) are arranged in pairs, wherein a first elastic arm (410), a second elastic arm (420), and an opening and closing window (430) between the first elastic arm (410) and the second elastic arm (420) are respectively provided along the length direction of the dorsal root nerve (300) region where they are located. The two elastic arms are used to elastically fix the stimulation contact (210) with increased resistance, and the opening and closing window (430) is used to engage the clamp (500) to open or close the two elastic arms.

7. The stimulating electrode according to claim 1 or 4, characterized in that The stimulator (100) is configured to deliver an electrical stimulation signal to a selected stimulation electrode (200) among the plurality of stimulation electrodes (200) when connected to it, the stimulator (100) delivering at least one stimulation mode to the selected stimulation electrode (200). The stimulator (100) adjusts the frequency, pulse width and intensity of the electrical stimulation signal according to the spatial position of the selected stimulation electrode (200) on the cauda equina (700) and the application time.

8. The stimulating electrode according to claim 7, characterized in that The waveform of the electrical stimulation signal applied by the stimulator (100) includes a unilateral rectangular waveform, a unilateral pulse waveform, a unilateral triangular waveform, a unilateral sine waveform, a unilateral random waveform, a unilateral band-modulated waveform, a unilateral pulse train waveform, a unilateral linear rise and fall waveform, or a combination thereof.

9. The stimulating electrode of claim 1, wherein, The current from the stimulation electrode (200) flows from the conductive loop (230) of the separated dorsal root nerve (300) region into the outer peritunic of the dorsal root nerve (300). The stimulation of the current causes a change in the potential difference between the inside and outside of the outer peritunic, which causes the outer peritunic to depolarize. The current propagates into the dorsal root nerve (300) to the peritunic of the nerve fiber, which causes the peritunic to depolarize. The current continues to flow to the inner peritunic surrounding the nerve fiber, which causes the action potential to be conducted along the axon.

10. The stimulating electrode of claim 1, wherein Paired stimulation contacts (210) are arranged on the dorsal root nerves (300) floating in the cerebrospinal fluid between the subarachnoid spaces.

11. The stimulating electrode according to claim 1 or 10, characterized in that The stimulation contacts (210) are designed to be connected to the electrode array of the stimulator (100) in a unilateral or bilateral arrangement, depending on the nerve to be stimulated.

12. A selective stimulation system, in particular an implantable selective spinal nerve root stimulation system based on the operation of the stimulation electrode according to any one of claims 1 to 11, characterized in that The system includes: A stimulator (100) is used to generate an electrical stimulation signal with a frequency, pulse width, and intensity to induce motor commands in the affected limb of the patient. At least one stimulating electrode (200) with a stimulating contact (210) at its distal end extends cephalicly along the course of the cauda equina (700), emerges from the dural sac region at the midline, passes through the interspinous space from the inside out through the skin, or is directly connected to the stimulator (100) along a subcutaneous tunnel. The stimulation electrode (200) has a stimulation contact (210) that is elastically fixed to the region of the freed dorsal root nerve (300) in a circumferential manner. The resistance of the stimulation contact (210) to the cerebrospinal fluid is greater than the resistance between the stimulation contact (210) and the outer pericardium that is elastically fixed to the dorsal root nerve (300). The stimulation electrodes (200) are arranged in pairs with stimulation contacts (210). The paired stimulation contacts (210) are spaced apart by a certain distance, which creates a signal loop between the paired stimulation contacts (210). This allows the electrical stimulation signal provided by the stimulator (100) to travel from the first stimulation contact (211) elastically fixed to the first region (310) of the dorsal root nerve (300) to the second stimulation contact (212) elastically fixed to the second region (320) of the dorsal root nerve (300), thereby inducing a current in the dorsal root nerve (300) along the path from the first region (310) of the dorsal root nerve (300) to the second region (320) of the dorsal root nerve (300). The stimulation contacts (210) of the stimulation electrode (200) are elastically fixed to the freed dorsal root nerve (300) region by a C-shaped elastic arm (400) in a circumferentially applied force-encircling manner.

13. A selective stimulation system characterized by, The system includes: Stimulator (100) for generating electrical stimulation signals; The stimulating electrode (200) connected to the stimulator (100) has a conductive ring (230) of its C-shaped elastic arm (400) in contact with the outer beam membrane; A biosignal acquisition module, used to acquire electromyographic signals from the human body, and The closed-loop controller is configured as follows: The movement phases are divided in real time according to the spectral characteristics of electromyography signals; the corresponding stimulation electrodes (200) are activated according to the pre-stored movement mode time sequence table; and the stimulation intensity ratio of different spinal nerve stimulation segments is dynamically adjusted according to the body position sensor data.

14. The system of claim 13, wherein, The closed-loop controller also includes a motion intention decoding unit that analyzes the time-frequency characteristics of electromyographic signals and a neural activation template that stores several basic motion patterns.

15. The system of claim 13, wherein, The closed-loop controller is also configured to control the intensity and duration of stimulation applied by the stimulator (100) to the target spinal nerve root according to the limb motor function goals that the patient expects to achieve.

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