Flexible spiral beam inner electrode with stress buffer structure

Abstract

The invention relates to the technical field of biomedical engineering and implantable medical instruments, and discloses a flexible spiral beam inner electrode with a stress buffer structure and a nerve regulation and control system. The electrode comprises a flexible spiral carrier made of a biocompatible elastic material, wherein the carrier is provided with a tube cavity along the central axis for accommodating a temporary support rod; a plurality of stimulation contacts distributed on the surface of the carrier form a three-dimensional contact array; the conductive traces are serpentine and release stress through geometric expansion when the carrier is deformed. The system further comprises a multi-channel pulse generator for realizing space-time cooperative selective stimulation. According to the application, the problems that a flexible electrode wire is easy to break and difficult to implant are solved, selective activation of sports fibers is realized, and pain caused by activation of sensory fibers is avoided.

Description

Technical Field

[0001] This application relates to the fields of biomedical engineering and implantable medical device technology, and in particular to an intrafascicular electrode and neuromodulation system technology for peripheral nerve function reconstruction. Background Technology

[0002] Peripheral nerve electrical stimulation (PES) is an important means of restoring function to paralyzed limbs caused by spinal cord injury, stroke, or peripheral nerve damage. In clinical applications, this technology is used in various specific scenarios: for example, for patients with spinal cord injury, stimulation of the peripheral nerves in the lower limbs can restore standing and walking function; for patients with stroke sequelae, stimulation of the upper limb nerves can restore hand grasping ability; and for patients with bladder dysfunction, stimulation of the pelvic nerves can restore urinary control. In these applications, electrodes need to be implanted into a mixed nerve containing both motor and sensory nerve fibers, and electrical stimulation is applied to activate the motor nerves to produce functional muscle contractions.

[0003] However, existing peripheral nerve electrical stimulation techniques face several technical challenges in the aforementioned clinical applications.

[0004] First, existing electrodes have significant shortcomings in selectivity. Whether it is an extrafascicular electrode surrounding the nerve or a rigid intrafascicular electrode penetrating inside the nerve, when attempting to activate motor nerve fibers, they often inevitably activate nearby sensory nerve fibers simultaneously, causing patients to experience unbearable sensations such as pain and burning, which seriously affects treatment compliance and efficacy.

[0005] Secondly, existing rigid or semi-rigid electrodes are prone to causing nerve tissue damage after long-term implantation. Due to the significant mechanical mismatch between the electrode material and soft nerve tissue, rigid electrodes will repeatedly rub, shear, or compress the nerve during physical activities, triggering chronic inflammatory reactions and fibrosis, ultimately leading to a decline in electrode performance or even failure.

[0006] Furthermore, electrodes made of ultra-flexible materials, used to address tissue damage, face challenges in terms of conductivity reliability and implantability. When the flexible carrier stretches and contracts with the nerve, the attached metal wires are prone to fatigue breakage; simultaneously, overly soft electrodes lack sufficient rigidity to penetrate the nerve sheath, making precise implantation difficult.

[0007] Therefore, there is an urgent need for a new technical solution that can achieve highly selective neural stimulation while also ensuring long-term biocompatibility, electrical reliability, and surgical operability. Summary of the Invention

[0008] The purpose of this application is to provide a flexible helical bundle internal electrode with a stress-buffering structure to solve the problems mentioned in the background art.

[0009] This application discloses a flexible helical bundle internal electrode with a stress-buffering structure, comprising: The flexible helical carrier is made of biocompatible elastic material, has a preset three-dimensional helical shape, and has a cavity along its central axis for accommodating temporary support rods. A three-dimensional contact array, comprising multiple stimulation contacts distributed on the surface of the flexible helical carrier; The stress-buffered interconnecting wire includes multiple conductive traces integrated on the flexible spiral carrier, the conductive traces respectively connecting the stimulation contact and the external interface; The conductive traces are geometrically serpentine, S-shaped, or wavy, and are configured to release stress and maintain electrical continuity when the flexible helical carrier undergoes axial stretching or bending deformation by unfolding its geometric shape.

[0010] In a preferred embodiment, each stimulation contact in the three-dimensional contact array is configured to be exposed only toward the inside or side of the flexible helical carrier, and the back of the stimulation contact is covered with an insulating layer to reduce leakage of current outward from the nerve bundle.

[0011] In a preferred embodiment, the plurality of stimulation contacts are distributed along the spiral ridge of the flexible spiral carrier, forming a 360-degree surround coverage of the internal fibers of the nerve bundle.

[0012] In a preferred embodiment, the flexible helical carrier has a variable pitch feature, wherein the pitch at both ends of the flexible helical carrier is smaller than the pitch in the middle part, presenting a structure that is dense at both ends and sparse in the middle.

[0013] In a preferred embodiment, the linewidth of the conductive trace is 10-50µm, the amplitude of the meandering geometry is 50-200µm, and the wavelength is 100-500µm.

[0014] In a preferred embodiment, the flexible helical carrier is in the shape of a helical column with an outer diameter of 0.5-2.0 mm, a pitch of 0.5-3.0 mm, and 3-8 helical turns; the diameter of the lumen is 100-300 µm.

[0015] In a preferred embodiment, the biocompatible elastic material is medical-grade silicone or liquid silicone (LSR) with a Young's modulus of less than 1 MPa; the impedance of the stimulation contact is 1-20 kΩ, and the surface is provided with a low-impedance coating, the low-impedance coating material being selected from titanium nitride (TiN) or platinum black (Pt-Black).

[0016] In a preferred embodiment, a temporary support rod is also included, which is removably inserted into the lumen and configured to provide temporary rigidification support for the flexible helical carrier during implantation.

[0017] In a preferred embodiment, the temporary support rod is made of a biodegradable material, including silk fibroin.

[0018] In a preferred embodiment, the temporary support rod is made of metal wire, including tungsten wire.

[0019] In a preferred embodiment, the multi-channel pulse generator is connected to multiple stimulation contacts of the flexible spiral bundle inner electrode, and is configured to independently control the discharge time, discharge intensity, and waveform of each stimulation contact.

[0020] In a preferred embodiment, the multichannel pulse generator is configured to perform an anode blocking strategy, forming a virtual anode barrier along the sensory fiber pathway by applying an inhibitory current at selected anode contacts to inhibit the activation of sensory nerves.

[0021] In a preferred embodiment, the multichannel pulse generator is configured to output a quasi-trapezoidal wave or an asymmetric biphasic wave optimized for the motion fibers, utilizing the difference in chronaxie between the motion fibers and the sensory fibers to amplify the activation threshold gap.

[0022] In a preferred embodiment, the multichannel pulse generator is further configured to combine and control multiple adjacent stimulation contacts to form a virtual contact, thereby precisely guiding the shape and direction of the current field by adjusting the current ratio of each contact.

[0023] This application also provides a spatiotemporal coordinated selective neural modulation system, comprising: The aforementioned flexible helical bundle inner electrode with stress-buffering structure; and A multi-channel pulse generator is connected to multiple stimulation contacts of the inner electrode of the flexible spiral bundle, and is configured to independently control the discharge time, discharge intensity and waveform of each stimulation contact.

[0024] In a preferred embodiment, the multichannel pulse generator is configured to perform an anode blocking strategy, forming a virtual anode barrier along the sensory fiber pathway by applying an inhibitory current at selected anode contacts to inhibit the activation of sensory nerves.

[0025] In a preferred embodiment, the multichannel pulse generator is configured to output a quasi-trapezoidal wave or an asymmetric biphasic wave optimized for the motion fibers, utilizing the time-value difference between the motion fibers and the sensory fibers to amplify the activation threshold gap.

[0026] In a preferred embodiment, the pulse width of the quasi-trapezoidal wave is 50-200 μs, and the rise time is 10-50 μs.

[0027] In a preferred embodiment, the first phase pulse width of the asymmetric biphase wave is 50-150 μs, the second phase pulse width is 2-4 times that of the first phase, and the ratio of the amplitude of the first phase to the amplitude of the second phase is 2:1 to 4:1.

[0028] In a preferred embodiment, the multichannel pulse generator is further configured to combine and control multiple adjacent stimulation contacts to form virtual contacts, and to precisely guide the shape and direction of the current field by adjusting the current ratio of each contact.

[0029] The technical solution of this application addresses a long-standing technical pain point in the field of hybrid neural electrical stimulation. Through the synergistic combination of multiple technical means, the following technical effects are achieved: To address the technical challenge of resolving the contradiction between flexibility and conductive stability, this application designs the conductive traces integrated onto a flexible helical carrier as a serpentine, S-shaped, or wavy geometric structure. This allows the conductive traces to release stress through the unfolding of their meandering geometry when the flexible helical carrier undergoes axial stretching or bending deformation due to the physiological movement of nerves, rather than relying on the limited ductility of the metal material itself to withstand the deformation. This design fundamentally eliminates the risk of fatigue fracture in traditional flexible electrodes with straight wires under repeated deformation, ensuring electrical continuity of the electrode under long-term dynamic load conditions, significantly extending the electrode's lifespan, and giving it the reliable potential for long-term clinical implantation.

[0030] To address the technical challenge of "difficult implantation of ultra-flexible electrodes," this application achieves reversible switching of electrode stiffness by creating a through- or semi-through lumen along the central axis of a flexible helical carrier, coupled with a removable temporary support rod inserted into the lumen. During implantation, the temporary support rod provides temporary stiffening support to the originally flexible helical carrier, enabling the electrode to penetrate or spiral into the epineurium and perineurium with sufficient axial stiffness. After implantation, by removing the support rod or waiting for the biodegradable material support rod to dissolve naturally, the electrode immediately returns to its ultra-flexible state, flexibly conforming to the inside of the nerve bundle. This "temporary stiffening" mechanism solves the engineering problem of "inability to insert or accurately position" of ultra-flexible electrodes, achieving minimally invasive and precise intra-bundle implantation, while preserving excellent biomechanical compliance between the implanted electrode and nerve tissue.

[0031] To address the core technical challenge of pain caused by poor selectivity, this application utilizes a three-dimensional contact array distributed along the spiral ridge of a flexible spiral carrier. This allows the stimulation contacts to form a 360-degree surround coverage of the fibers within the nerve bundle after implantation, providing a structural basis for precise stimulation of target fibers from multiple spatial orientations. Furthermore, by configuring the stimulation contacts to be oriented to expose only towards the inner or lateral side of the spiral while having an insulating layer covering the back, ineffective leakage of current to the outside of the nerve bundle is effectively reduced, improving the focusing of the current field. Based on this hardware, the spatiotemporal coordinated selective neuromodulation system of this application independently controls the discharge time, discharge intensity, and waveform of each contact through a multi-channel pulse generator. In the spatial dimension, it executes an anodic blocking strategy to form a virtual anodic barrier along the sensory fiber path. In the temporal dimension, it outputs quasi-trapezoidal waves or asymmetric biphasic waves optimized for motor fibers to utilize the temporal differences between motor and sensory fibers to amplify the activation threshold gap. The synergistic effect of spatial and temporal dimensions enables the system to "carve" a highly controllable current field in shape, direction, and intensity within the nerve bundle, precisely focusing the stimulation current onto the target motor fiber to reach its activation threshold, while keeping adjacent sensory fibers in a weak zone of the current field and thus achieving a painless selective stimulation effect where motor fibers are activated while sensory fibers are not.

[0032] Furthermore, by using medical-grade silicone or liquid silicone with a low Young's modulus to create a flexible helical carrier, its mechanical properties closely resemble those of nerve tissue. After implantation, the electrode can move, bend, and deform slightly along with the nerve, significantly reducing friction, shearing, and compression between the electrode and fragile nerve tissue, fundamentally lowering the risk of chronic injury, inflammation, and fibrosis. Optionally, by designing the flexible helical carrier as a variable-pitch structure with smaller pitch at both ends than in the middle, the electrode ends gain stronger anchoring ability to prevent axial slippage, while the middle portion maintains better flexibility to adapt to the bending movements of the nerve, achieving a balanced optimization of positioning stability and mechanical compliance.

[0033] Furthermore, by applying a low-resistance coating made of titanium nitride or platinum black to the surface of the stimulation contact, the electrode-tissue interface impedance is reduced, the charge injection efficiency is improved, which helps to reduce the voltage amplitude required for stimulation, reduce the occurrence of electrochemical side reactions, and improve the safety and effectiveness of stimulation.

[0034] Furthermore, by combining and controlling multiple adjacent stimulation contacts to form virtual contacts, and by adjusting the current ratio of each contact to precisely guide the shape and direction of the current field, the system can achieve a finer spatial resolution than the spacing between physical contacts even if the position of the physical contacts is fixed. This further enhances the system's ability to regulate the current field and precisely activate the target nerve fibers.

[0035] The specification of this application contains numerous technical features distributed across various technical solutions. Listing all possible combinations of these technical features (i.e., technical solutions) would make the specification excessively lengthy. To avoid this problem, the various technical features disclosed in the above-described invention, the various technical features disclosed in the following embodiments and examples, and the various technical features disclosed in the accompanying drawings can be freely combined to form various new technical solutions (all of which are considered to have been described in this specification), unless such a combination of technical features is technically infeasible. For example, one example discloses feature A+B+C, and another example discloses feature A+B+D+E. Features C and D are equivalent technical means that serve the same function, and technically only one needs to be used; they cannot be used simultaneously. Feature E can technically be combined with feature C. Therefore, the solution A+B+C+D should not be considered as described because it is technically infeasible, while the solution A+B+C+E should be considered as described. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the structure of a ring-shaped neural electrode in the prior art, intended to demonstrate the lack of focus of the current field in conventional techniques.

[0037] Figure 2 This is a schematic diagram of the overall three-dimensional structure (form before sheet unfolding) of a flexible spiral bundle inner electrode with a stress-buffering structure according to an embodiment of this application.

[0038] Figure 3 This is a planar manufacturing view (flattened state) of the inner electrode of the flexible helical bundle according to an embodiment of this application, with a partial magnified illustration of the microscopic serpentine / winding geometry of the stress-buffered interconnect wires.

[0039] Figure 4 This is a three-dimensional schematic diagram of a flexible spiral bundle inner electrode in the shape of a helical column according to a preferred embodiment of the present application, which particularly shows a central lumen inlet extending axially to accommodate a temporary support rod.

[0040] in: 10: Flexible Helical Carrier 20: Stimulating Contact Points 30: Stress-buffered interconnecting wire 40: Temporary support rod Detailed Implementation

[0041] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0042] Explanation of some concepts: Mixed nerves are peripheral nerve structures that simultaneously contain motor nerve fibers responsible for transmitting central commands to muscles and sensory nerve fibers responsible for transmitting peripheral sensory information back to the central nervous system.

[0043] Intrafascicular electrodes are neural electrodes whose working ends are configured to penetrate the epineurium and reside inside the nerve bundle, in order to distinguish them from extrafascicular electrodes (such as Cuff electrodes) that surround the outside of the nerve.

[0044] Flexible helical carriers refer to electrode body structures made of low-modulus biocompatible elastic materials with a preset three-dimensional helical geometry. They are used to carry stimulation contacts and conductive traces and provide radial support.

[0045] A three-dimensional contact array refers to a spatial array formed by multiple stimulation contacts distributed along the surface of a flexible spiral carrier. Its configuration is such that, after implantation, it surrounds and covers the fibers within the nerve bundle from different angles and depths.

[0046] Stress-buffered interconnects are conductive traces that are geometrically serpentine, S-shaped, or wavy. They are configured to absorb stress generated by carrier deformation through the unfolding or folding of their geometry, in order to maintain electrical continuity.

[0047] Temporary support rods are rigid or semi-rigid rod-shaped components that can be removably inserted into the central lumen of a flexible helical carrier to provide temporary axial stiffness for the flexible carrier during implantation surgery to assist in implantation.

[0048] Spatiotemporal synergistic selective stimulation refers to a technique that simultaneously utilizes anodizing strategies in the spatial dimension and waveform optimization strategies in the temporal dimension to synergistically regulate electrical stimulation, thereby amplifying the difference in activation thresholds between motor and sensory fibers.

[0049] Anodic blocking refers to a technique that uses the hyperpolarization effect to suppress the excitation or conduction of nerve fibers near a specific contact point by applying an anodic current to that contact point, thereby forming a virtual electric field barrier.

[0050] A virtual contact point refers to a virtual stimulation center that is spatially synthesized by coordinating the current output of multiple physical contacts and adjusting their proportions.

[0051] Time value refers to the electrophysiological parameter that characterizes the excitability of nerve fibers, that is, the shortest time required to induce excitation when the nerve is stimulated with twice the base intensity. This application utilizes the time value differences of different types of fibers to achieve selective activation.

[0052] The following is a brief summary of some of the innovative aspects of this application: In summary, the technical solution of this application is not a simple combination or patchwork of various known technical elements in the prior art, but rather based on the inventor's profound insight into the "selectivity-reliability-implantability" triadic contradiction in the field of hybrid neuroelectric stimulation. Through a unique structure-function coupling design, it achieves this through a flexible helical carrier (see...). Figure 4 ), stress-relief interconnecting wires (see) Figure 3 A mutually dependent and indispensable technical chain is established between the central cavity and the temporary support rod, thereby achieving a synergistic effect that exceeds the simple superposition of individual technical elements.

[0053] Specifically, the starting point of this application's technical concept lies in the recognition that: to achieve highly selective separation and activation of motor and sensory fibers within a nerve bundle, stimulation contacts must be arranged three-dimensionally within the nerve bundle to form a multi-angle surround and coverage of the fibers; however, achieving this three-dimensional arrangement requires the use of intra-bundle electrode structures capable of penetrating deep into the nerve bundle; and to avoid chronic mechanical damage to fragile nerve tissue caused by the intra-bundle electrodes, the electrode carrier must possess low-modulus flexibility similar to that of nerve tissue. This leads to the first layer of technical contradiction: while ultra-flexible carrier materials solve the biomechanical compliance problem, they bring two derivative engineering challenges—first, the metallic conductive traces attached to the flexible carrier are prone to fatigue fracture when the carrier stretches and deforms with the physiological expansion and contraction of the nerve, leading to electrical failure of the electrode; second, the ultra-flexible electrode, like a "noodle," lacks sufficient axial stiffness to penetrate the epineurium and perineurium, making precise implantation difficult.

[0054] To address the aforementioned intertwined technical contradictions, this application does not solve each problem in isolation. Instead, it organically integrates three structural elements: the three-dimensional spiral geometry of the flexible spiral carrier, the serpentine geometric structure of the conductive traces, and the cavity running through the central axis of the carrier. This allows each element to fulfill its individual function while simultaneously creating the structural prerequisites and spatial conditions necessary for the others to function. More specifically, the spiral columnar shape of the flexible spiral carrier (see...) Figure 4 This not only provides a geometrical basis for the three-dimensional contact array to be distributed along the spiral ridge, allowing the contacts to form a 360-degree coverage of the fibers inside the nerve bundle, but also the inherent radial elasticity of its spiral structure provides support for the self-anchoring of the electrodes within the nerve bundle, eliminating the need for additional fixing mechanisms; at the same time, the conductive traces are designed to be serpentine, S-shaped, or wavy (see...). Figure 3 This design allows the carrier to release stress through geometric expansion rather than plastic extension of the metal material itself when it undergoes axial tension or bending deformation. This design concept of "replacing material extensibility with geometric compliance" is based on the predictable deformation pattern brought about by the spiral shape of the flexible carrier. Furthermore, the coaxial configuration of the cavity set along the central axis of the flexible spiral carrier with the spiral carrier allows the temporary "straightening" and stiffening of the originally soft spiral structure along the spiral axis when a temporary support rod is inserted into the cavity. Once the support rod is removed or degraded, the carrier restores its preset spiral flexible state. The realization of this "reversible state switching" function depends on the precise geometric coaxial relationship between the cavity and the spiral carrier, as well as the inherent elastic memory characteristics of the carrier material.

[0055] Therefore, it is evident that the helical shape of the flexible helical carrier, the serpentine geometry of the conductive traces, and the coaxial configuration of the central lumen in this application exhibit a structural nesting, functional synergy, and effect enhancement relationship. The absence or alteration of any single element will prevent the overall technical solution from achieving its intended comprehensive technical effect of "high selectivity, high reliability, and minimally invasive implantation." This non-linear synergistic relationship among multiple elements, transcending simple superposition, is not something that those skilled in the art could easily conceive of or anticipate based on existing technology.

[0056] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0057] Through long-term and in-depth research, the inventors of this application have discovered that the problems of poor selectivity, tissue damage, insufficient reliability, and implantation difficulties faced by existing peripheral nerve electrical stimulation technology actually constitute a set of interrelated and mutually restrictive technical contradictions. The reason why existing technologies have failed to effectively solve these problems is that they have failed to systematically understand and deal with the inherent connections between these contradictions.

[0058] Through in-depth analysis of the principles of existing extra-fascicular and intra-fascicular electrodes, the inventors discovered that the poor selectivity of extra-fascicular electrodes (such as cuff electrodes) stems from their location outside the nerve, far from the target fiber. The resulting electric field, like a "floodlight," roughly covers the entire nerve cross-section, failing to distinguish between the interwoven motor and sensory fibers. While existing intra-fascicular electrodes shorten the distance to the target fiber by penetrating the nerve interior, the limited spatial distribution of contact points and lack of precise current field modulation capabilities still hinder differentiated activation of different fiber types. The inventors realized that truly solving the selectivity problem requires not only physical proximity of the electrode to the target fiber but also a three-dimensional surround coverage of the nerve bundle with the contact points, and the ability to precisely "sculpt" the current field.

[0059] Further research by the inventors revealed that, in order to achieve the aforementioned three-dimensional coverage and reduce damage to soft neural tissue, the electrode carrier must be made of a flexible material with extremely low modulus—however, this choice led to two other technical challenges. Through long-term practical observation of failure modes in flexible electronic devices, the inventors discovered that when the flexible carrier undergoes physiological expansion and contraction with the nerve, the traditional straight metal wires attached to it are subjected to repeated tensile stress. Due to the limited ductility of the metal material itself, fatigue fracture is highly likely after multiple deformation cycles, leading to the loss of electrical connectivity of the electrode—a common engineering problem restricting the long-term reliability of flexible neural electrodes. After in-depth consideration, the inventors creatively proposed that the wires should be designed with a meandering geometric structure, allowing them to absorb stress through geometric unfolding or folding during carrier deformation, rather than relying on the ductility of the metal material itself.

[0060] Meanwhile, through analysis of the surgical implantation process, the inventors discovered that flexible electrodes made of ultra-low modulus materials, like a "noodle," lack sufficient axial stiffness to penetrate or screw into the tough epineurium and perineurium, making precise implantation almost impossible. The inventors recognized that the seemingly irreconcilable contradiction between "the need for ultra-flexibility to achieve biomechanical compliance" and "the need for sufficient stiffness to achieve precise implantation" could be simultaneously satisfied if the two states could be decoupled over time—that is, temporarily gaining stiffness during implantation and restoring flexibility afterward. Based on this insight, the inventors creatively proposed a "temporary stiffening" mechanism that involves pre-setting a lumen within a flexible carrier and using a removable or biodegradable temporary support rod.

[0061] More importantly, through in-depth research into neuroelectrophysiology, the inventors discovered that even with a precise three-dimensional contact array, spatial contact configuration alone is insufficient to achieve complete separation and activation of motor and sensory fibers. Further analysis revealed inherent differences in electrophysiological parameters such as time-dependent nerve fibers, providing a possibility for further enhancing selectivity from a temporal perspective. The inventors thus proposed a "spatiotemporal synergy" stimulation strategy: spatially, anodic blockade is implemented using a three-dimensional contact array to create an inhibitory barrier along the sensory fiber pathway; temporally, a specific waveform optimized for motor fibers is employed to widen the difference in activation thresholds between the two types of fibers; the synergistic effect of these two dimensions significantly improves selectivity.

[0062] Based on the above in-depth research, the inventors of this application propose a spatiotemporally coordinated flexible spiral electrode system with a central lumen-assisted implantation and a serpentine stress-buffered lead wire. This system systematically solves the aforementioned interrelated technical problems through the synergistic cooperation between specific structural elements. The implementation process of this application is described in detail below through specific embodiments.

[0063] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0064] Example 1: Flexible spiral bundle internal electrode with stress buffer structure This embodiment provides a flexible helical bundle electrode with a stress-buffering structure. This electrode is mainly used in the field of peripheral nerve function reconstruction, and is particularly suitable for selective electrical stimulation of mixed nerves. It should be noted that mixed nerves refer to nerve bundles that simultaneously contain motor nerve fibers and sensory nerve fibers. The core objective of this application is to achieve precise selection by activating only motor nerves to restore limb function and not activating sensory nerves to avoid pain when electrically stimulating mixed nerves.

[0065] Reference Figure 4 In this embodiment, the flexible helical bundle internal electrode has an overall helical columnar structure, resembling a miniature telephone line. This electrode mainly comprises three core components: a flexible helical carrier 10, a three-dimensional contact array, and stress-buffered interconnecting wires 30. For example... Figure 2 As shown, these three parts work together to achieve the electrode's highly selective stimulation function and long-term reliability. Each component will be described in detail below.

[0066] Regarding the flexible helical carrier 10, it is the structural basis of the electrode of this application, and undertakes multiple functions such as supporting the stimulation contact 20, accommodating the interconnecting wires, and achieving biomechanical matching with nerve tissue.

[0067] Specifically, the flexible helical carrier 10 is made of a biocompatible elastic material and has a preset three-dimensional helical shape. In this embodiment, the biocompatible elastic material is preferably medical-grade silicone or liquid silicone with a Young's modulus of less than 1 MPa. It should be noted that choosing a low-modulus material has significant technical implications: nerve tissue itself is very soft, and its modulus is typically in the kPa range. Using a flexible material with a modulus close to that of nerve tissue to make the electrode carrier allows the electrode to move, bend, and deform slightly along with the nerve after implantation, thereby greatly reducing friction, shearing, and compression between the electrode and the fragile nerve tissue. This excellent mechanical compliance fundamentally reduces the risk of chronic injury, inflammation, and fibrosis, ensuring that the electrode can work stably and safely for a long time.

[0068] Furthermore, the flexible helical carrier 10 is integrally helical cylindrical in shape. See also Figure 4 In a preferred embodiment, the outer diameter of the flexible helical carrier 10 can be adapted to the diameter of the target nerve bundle. For example, the outer diameter can be set in the range of 0.5-2.0 mm; the pitch can be set in the range of 0.5-3.0 mm; and the number of helical turns can be set in the range of 3-8 turns. Those skilled in the art will understand that the above parameter ranges are merely exemplary and can be adjusted according to specific neuroanatomical structures and clinical needs in practical applications.

[0069] Furthermore, the flexible helical carrier 10 has a cavity along its central axis for accommodating the temporary support rod 40. This cavity extends through or partially extends through the entire carrier along the helical central axis. Exemplarily, the diameter of the cavity can be set in the range of 100-300 μm. The arrangement of this cavity is a key structural feature of this application in solving the problem of difficult implantation of ultra-flexible electrodes, and its specific function will be described in detail in the section on the temporary support rod 40 later.

[0070] Optionally, the flexible helical carrier 10 can also have a variable pitch feature. More specifically, the pitch at both ends of the flexible helical carrier 10 is smaller than the pitch in the middle, presenting a structure that is denser at both ends and sparser in the middle. The technical effect of this variable pitch design is that the denser helical structure at both ends provides better anchoring capability, which helps the electrode to remain stably within the nerve bundle; while the sparser helical structure in the middle provides greater flexibility and compliance, which is beneficial for adapting to the physiological movement of the nerve. The structure design of dense at both ends and sparse in the middle enables the electrode to have both good positioning stability and mechanical compliance.

[0071] The three-dimensional contact array is the core actuator for the selective stimulation function of the electrodes in this application. This array includes multiple stimulation contacts 20 distributed on the surface of the flexible helical carrier 10.

[0072] Specifically, multiple stimulation contacts 20 are distributed along the spiral ridge of the flexible helical carrier 10. After the electrodes are implanted into the nerve bundle, these contacts surround the fibers within the nerve bundle from different angles and depths (i.e., in three-dimensional space), forming a 360-degree surround coverage of the fibers inside the nerve bundle. This three-dimensional array of contacts allows the electrodes to stimulate the nerve fibers from multiple spatial orientations, providing a structural basis for subsequent precise current field modulation.

[0073] Furthermore, each stimulation contact 20 in the three-dimensional contact array is configured to be exposed only towards the inner or lateral side of the flexible helical carrier 10, and the back of the stimulation contact 20 is covered with an insulating layer. This directional exposure design has significant technical implications: because the contacts are exposed only towards the inner or lateral side of the helix, the current is primarily conducted towards the interior of the nerve bundle; while the insulating layer on the back effectively prevents current leakage to the exterior of the nerve bundle. This design reduces ineffective current diffusion, improves the focusing of the current field, and thus enhances the selectivity of stimulation to the target nerve fiber.

[0074] Furthermore, the impedance of the stimulation contact 20 is preferably set in a low range, exemplarily 1-20 kΩ. To further reduce the electrode-tissue interface impedance and improve charge injection efficiency, a low-impedance coating may be provided on the surface of the stimulation contact 20. This low-impedance coating material may be selected from titanium nitride or platinum black. The low-impedance coating helps to reduce the voltage amplitude required for stimulation, decrease the occurrence of electrochemical side reactions, and improve the safety and effectiveness of stimulation.

[0075] Regarding the stress-buffered interconnecting wire 30, it is one of the core innovations that distinguishes this application from the prior art, and it solves a common engineering problem that has long existed in the field of flexible electronic implants: the contradiction between flexibility and conductivity stability.

[0076] Specifically, the stress-buffered interconnecting wire 30 includes multiple conductive traces integrated on the flexible helical carrier 10, which connect the stimulation contact 20 to the external interface. Each stimulation contact 20 is connected to the external interface through an independent conductive trace, thereby enabling independent addressing control of each contact.

[0077] The key feature of this application is that the conductive traces are not in a traditional straight-line geometric shape, but rather meander in a serpentine, S-shaped, or wavy form. This meandering geometric design allows the conductive traces to be configured to release stress and maintain electrical continuity when the flexible helical carrier 10 undergoes axial tension or bending deformation through the unfolding of its geometric shape.

[0078] It should be noted that the working principle of this design can be understood as follows: when the helical carrier is stretched along with the nerve, the curved portion of the serpentine wire gradually "straightens" to release stress; when the carrier is compressed, the curved portion of the wire "folds" to adapt to deformation. This geometric compliance allows the stress during carrier deformation to be absorbed by the geometric unfolding / folding of the wire, rather than relying on the ductility of the metal material itself. Since the ductility of metal materials (such as gold and platinum) is limited, fatigue fracture is prone to occur under repeated deformation, while the serpentine geometric design of this application effectively eliminates this risk.

[0079] Reference Figure 3 The flattened schematic diagram shows simplified straight lines for the conductors. However, in the preferred embodiment of this application, the conductors connecting the contact point and the external interface exhibit a continuous serpentine, S-shaped, or wavy geometric structure at the microscopic level. For example, the linewidth of the conductive trace can be set to a range of 10-50 μm, the amplitude of the serpentine geometric structure can be set to a range of 50-200 μm, and the wavelength can be set to a range of 100-500 μm. Those skilled in the art will understand that the above parameters can be optimized and adjusted according to specific material properties and expected deformation.

[0080] In terms of manufacturing process, optionally, serpentine metal wires and contact arrays can first be formed on a planar substrate (such as polyimide or parylene) using photolithography; then, the planar structure can be rolled or encapsulated in liquid silicone, and the central cavity and spiral shape can be formed by molding. This process route of first processing the planar surface and then forming the three-dimensional shape not only ensures the processing accuracy of the micro-wire pattern, but also realizes the manufacturing of complex three-dimensional spiral structures.

[0081] Regarding the temporary support rod 40, it is a key component in this application for solving the problem of difficult implantation of ultra-flexible electrodes.

[0082] Specifically, in order to achieve a good mechanical fit with nerve tissue, the flexible helical carrier 10 of this application uses a flexible material with extremely low modulus. However, this ultra-flexible design brings an operational problem: this "noodle"-shaped electrode lacks sufficient stiffness to penetrate or screw into the tough epineurium and perineurium, making the surgery difficult to perform or inaccurate in positioning.

[0083] To address this issue, this application includes a cavity pre-formed on the central axis of the flexible helical carrier 10, and a corresponding temporary support rod 40. The temporary support rod 40 is removably inserted into the cavity and is configured to provide temporary rigidification support for the flexible helical carrier 10 during implantation.

[0084] Furthermore, there are multiple options for the material of the temporary support rod 40.

[0085] In one alternative approach, the temporary support rod 40 is made of a biodegradable material, including but not limited to silk fibroin. With this approach, the temporary support rod 40 does not need to be actively removed after implantation; instead, it gradually degrades and dissolves within the body, allowing the electrode to naturally return to its ultra-flexible state. The advantage of this approach is its simplicity and reduced surgical steps.

[0086] In another alternative, the temporary support rod 40 is made of metal wire, including but not limited to tungsten wire. With this approach, the wire needs to be actively removed after implantation. The advantages of this method are its mature technology and good controllability.

[0087] Regardless of the material used, the core function of the temporary support rod 40 remains the same: to provide temporary mechanical support for the ultra-flexible electrode during the implantation phase, giving it sufficient rigidity to complete the puncture or screwing operation; and after implantation, to remove the support by pulling it out or degrading it, allowing the electrode to return to its original ultra-flexible state, thereby achieving a good mechanical match with the nerve tissue. This "temporary rigidification" design ingeniously solves the engineering problem of ultra-flexible electrodes being "unable to be inserted or accurately positioned".

[0088] The implantation and working principle of the electrodes in this application will be explained below.

[0089] Based on the above structural design, the implantation and workflow of the electrodes in this application are as follows.

[0090] During the assembly stage, the temporary support rod 40 is inserted into the central cavity of the electrode. At this time, the originally soft spiral electrode becomes straighter and harder, making it easier to operate.

[0091] During the implantation phase, the electrode is inserted or screwed into the target location along the long axis of the nerve bundle. Thanks to the support of the temporary support rod 40, the electrode possesses sufficient mechanical strength to complete the puncture procedure.

[0092] During the recovery phase, the support rod is removed (if it is a wire design) or the support rod is allowed to dissolve (if it is a biodegradable material design). The electrode then returns to its soft, helical state, flexibly conforming to the internal nerve tissue. At this point, the helical structure of the electrode provides moderate radial support, achieving self-anchoring within the nerve bundle; simultaneously, its flexibility allows it to move with the nerve, avoiding damage to the nerve tissue.

[0093] From a functional perspective, the core of the selective stimulation achieved by the electrodes in this application lies in their alteration of the shape and control method of the current field. Traditional electrodes act like a "floodlight," activating all surrounding nerve fibers (including motor and sensory fibers) when energized. The spiral electrodes of this application, however, function like a programmable three-dimensional spotlight array. Because the contacts are distributed in three-dimensional space and can be independently controlled, the system can "guide" the current through complex combinations of electrical signals. This allows the electrodes to "sculpt" a highly controllable current field in shape, direction, and intensity within the nerve bundle, precisely focusing the current onto the target motor fiber to reach its activation threshold; simultaneously, it cleverly positions the adjacent sensory fibers in a weaker region of the current field, keeping their activation level below the sensory threshold. Ultimately, this achieves the following: motor fibers are activated (muscle contraction), while sensory fibers are not activated (the patient experiences no pain).

[0094] Example 2: Spatiotemporal Coordination Selective Neuromodulation System This embodiment provides a spatiotemporal coordinated selective neuromodulation system. Based on the flexible helical bundle internal electrode described in Embodiment 1, the system is further configured with a multi-channel pulse generator to achieve a more advanced selective stimulation control strategy.

[0095] Specifically, the spatiotemporal coordinated selective neural modulation system of this embodiment includes: the flexible helical bundle internal electrode with stress buffer structure as described in Embodiment 1; and a multi-channel pulse generator.

[0096] The multi-channel pulse generator is connected to multiple stimulation contacts 20 of the flexible helical bundle inner electrode, and is configured to independently control the discharge time, discharge intensity, and waveform of each stimulation contact 20. This ability to independently control multiple channels is the hardware foundation for realizing spatiotemporally coordinated selective stimulation.

[0097] It should be noted that the so-called "spatiotemporal coordinated selective stimulation" refers to the system simultaneously and precisely controlling electrical stimulation from both spatial and temporal dimensions to achieve maximum separation of motor and sensory fibers. These will be explained in detail below.

[0098] Regarding the coordinated control of spatial dimensions, this application adopts an anode blocking strategy.

[0099] Specifically, the multichannel pulse generator is configured to execute an anodic blocking strategy. This strategy creates a virtual anodic barrier along the sensory fiber pathway by applying an inhibitory current to selected anodic contacts, thereby inhibiting the activation of sensory nerves. The principle behind this is that when a contact is set as an anode and a current is applied, the membrane potential of the nearby nerve fibers becomes hyperpolarized, meaning the membrane potential becomes more negative than the resting potential. This hyperpolarization effect inhibits the excitability of the nerve fibers, making them more difficult to activate.

[0100] In practical applications, the system can align the cathode contact with the location of the motor fiber bundle (for activation) and the anode contact with the location of the sensory fiber bundle (for blocking) based on the neural map information obtained from a pre-scan. Through this spatially differentiated configuration, while activating the target motor fibers, a "virtual anode barrier" is set up on the adjacent sensory fiber path, effectively inhibiting the excitation of sensory nerves.

[0101] Regarding the coordinated control of the time dimension, this application adopts a waveform optimization strategy.

[0102] Specifically, the multichannel pulse generator is configured to output a specific waveform optimized for motor fibers. This specific waveform can be a quasi-trapezoidal wave or an asymmetric biphasic wave. The technical principle behind using these specific waveforms lies in the differences in electrophysiological characteristics between motor and sensory fibers, particularly in parameters such as chronaxie and membrane capacitance. Chronaxie is an important parameter characterizing the excitability of nerve fibers, and different types of nerve fibers have different chronaxies. By designing specific pulse waveform parameters (such as pulse width, rising edge slope, etc.), the differences in chronaxie between motor and sensory fibers can be utilized to make the stimulation pulse more likely to activate motor fibers and less likely to activate sensory fibers, thereby further widening the gap in activation thresholds between the two.

[0103] Regarding virtual contact control, this is an advanced function in this application that enables refined current field regulation.

[0104] Furthermore, the multi-channel pulse generator can also be configured to combine and control multiple adjacent stimulation contacts 20 to form virtual contacts, and precisely guide the shape and direction of the current field by adjusting the current ratio of each contact.

[0105] More specifically, a virtual contact refers to creating a spatially equivalent "virtual" stimulation location by simultaneously controlling the current output of multiple physical contacts. For example, if two adjacent contacts A and B are activated simultaneously with different current intensities, the equivalent stimulation center will be located somewhere between A and B, depending on the current ratio between the two contacts. In this way, even if the positions of the physical contacts are fixed, the system can fine-tune the equivalent stimulation location by adjusting the current ratio, achieving a finer spatial resolution than the spacing between physical contacts.

[0106] The introduction of virtual contact technology further enhances the system's ability to control the current field, enabling the system to more accurately focus stimulation on the target motor fibers while avoiding sensory fibers.

[0107] Regarding system calibration and operation, a calibration process is typically required before actual system use. During calibration, the system sequentially scans each contact point, identifying the distribution areas of motor and sensory fibers within the nerve bundle by observing muscle contraction responses and patient sensory feedback. Based on the calibration results, the system automatically generates an optimized stimulation strategy, including: which contacts act as cathodes (aligning with motor fibers), which contacts act as anodes (aligning with sensory fibers for blocking), and the current intensity and waveform parameters of each contact. In subsequent treatment phases, the system executes spatiotemporally coordinated selective stimulation according to the optimized strategy.

[0108] The technical effects of this application are summarized below.

[0109] In summary, the technical solution of this application has the following significant technical effects: Firstly, in terms of reliability, the serpentine stress-buffered lead wire design solves the problems of easy breakage and short lifespan of traditional flexible electrode leads. The meandering geometry of the conductive traces can absorb stress by unfolding / folding when the carrier deforms, avoiding metal fatigue fracture and enabling the electrode to truly have the potential for long-term implantation.

[0110] Secondly, in terms of selectivity, a high degree of separation between motor and sensory fibers is achieved through a three-dimensional contact array combined with a spatiotemporal coordinated stimulation strategy. The combination of spatial anodic blocking and temporal waveform optimization effectively solves the problem of pain caused by traditional electrical stimulation.

[0111] Furthermore, in terms of biocompatibility, the flexible helical carrier 10 is made of low-modulus medical-grade silicone, whose mechanical properties are similar to those of nerve tissue. It can move and deform along with the nerve, greatly reducing the risk of chronic damage, inflammation and fibrosis.

[0112] Finally, regarding feasibility, the design of a central lumen combined with a temporary support rod 40 solves the operational challenge of implanting ultra-flexible electrodes. The temporary stiffening mechanism ensures that the electrode has sufficient mechanical strength during implantation and can return to its ultra-flexible state after implantation, thus balancing surgical operability and long-term biomechanical compatibility.

[0113] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

[0114] Furthermore, to enable those skilled in the art to better implement the spatiotemporal coordinated selective stimulation strategy of this application, the specific parameters of the stimulation waveform are explained below by way of example.

[0115] In neuroelectrophysiology, the chroma of motor nerve fibers (such as Aα fibers) is typically in the range of 50-100 μs, while the chroma of sensory nerve fibers (such as Aδ and C fibers) is typically greater than 200 μs. This application utilizes this difference to achieve selective activation—selecting a shorter pulse width can preferentially activate motor fibers while keeping sensory fibers in a subthreshold state.

[0116] In one specific implementation, the quasi-trapezoidal wave may optionally have the following parameter characteristics: pulse width of 50-200 μs, preferably 80-150 μs; rise time of 10-50 μs, preferably 20-40 μs, a slower rise time can reduce the instantaneous activation effect on large-diameter sensory fibers; fall time of 10-50 μs; and pulse amplitude of 0.1-5 mA, which is adjusted according to the activation threshold of the target fiber.

[0117] In another specific embodiment, optionally, the asymmetric biphasic wave has the following parameter characteristics: the pulse width of the first phase (stimulation phase) is 50-150 μs, and the pulse width of the second phase (charge balance phase) is 2-4 times that of the first phase; the phase interval between the first and second phases is 0-100 μs; the amplitude of the first phase is greater than that of the second phase, with a ratio of 2:1 to 4:1. This asymmetric design allows the first phase to effectively activate the moving fibers, while the wider but lower amplitude second phase is used for charge balance, avoiding electrochemical damage.

[0118] Regarding the specific parameters of the anode blocking strategy, in one implementation, optionally, the injection current amplitude at the anode contact is set to 1.2-2.0 times the cathode stimulation current amplitude to ensure that a sufficiently deep hyperpolarization barrier is formed in the sensory fiber path; the anode pulse can be applied synchronously with the cathode pulse, or it can be applied 10-100 μs in advance to form a pre-blocking effect.

[0119] Regarding the adjustment of the current ratio of the virtual contact, optionally, when it is necessary to position the equivalent stimulus location between two adjacent physical contacts A and B, this can be achieved by setting the current ratio between contacts A and B. For example, if I_A:I_B = 7:3 is set, the equivalent stimulus center will be located approximately 30% from contact A and approximately 70% from contact B. By continuously adjusting this ratio, continuous movement of the equivalent stimulus location can be achieved, with a spatial resolution reaching 1 / 10 to 1 / 20 of the distance between the physical contacts.

[0120] The choice of stimulation frequency depends on the specific clinical application. Optionally, for applications involving functional muscle contraction, the stimulation frequency is typically set to 20-50 Hz to produce smooth tetanic contractions; for applications involving pain suppression, the stimulation frequency can be set to a higher 80-150 Hz.

[0121] The above parameter ranges are only preferred examples. In actual applications, the system can automatically fine-tune based on feedback during the calibration process.

[0122] The above embodiments have the following technical effects: The technical solutions of the above embodiments address long-standing technical pain points in the field of hybrid neural electrical stimulation. Through the synergistic cooperation of multiple technical means, the following technical effects are achieved: To address the technical challenge of resolving the conflict between flexibility and conductive stability, the aforementioned embodiments design the conductive traces integrated onto the flexible helical carrier as serpentine, S-shaped, or wavy geometric structures. This allows the conductive traces to release stress through the unfolding of their meandering geometry when the flexible helical carrier undergoes axial stretching or bending deformation due to the physiological movement of nerves, rather than relying on the limited ductility of the metal material itself to withstand the deformation. This design fundamentally eliminates the risk of fatigue fracture in traditional flexible electrodes with straight wires under repeated deformation, ensuring electrical continuity of the electrode under long-term dynamic load conditions, significantly extending the electrode's lifespan, and giving it the reliable potential for long-term clinical implantation.

[0123] To address the technical challenge of "difficult implantation of ultra-flexible electrodes," the aforementioned embodiment achieves reversible switching of electrode stiffness by creating a through- or semi-through lumen along the central axis of a flexible helical carrier, coupled with a removable temporary support rod inserted into this lumen. During implantation, the temporary support rod, once inserted into the lumen, provides temporary stiffening support to the originally flexible helical carrier, enabling the electrode to possess sufficient axial stiffness to penetrate or spiral into the epineurium and perineurium. After implantation, by removing the support rod or allowing it to dissolve naturally from the biodegradable material, the electrode immediately returns to its ultra-flexible state, flexibly conforming to the interior of the nerve bundle. This "temporary stiffening" mechanism solves the engineering problem of "inability to insert or accurately position" ultra-flexible electrodes, achieving minimally invasive and precise intra-bundle implantation while preserving excellent biomechanical compliance between the implanted electrode and nerve tissue.

[0124] To address the core technical challenge of pain caused by poor selectivity, the aforementioned embodiments utilize a three-dimensional contact array distributed along the spiral ridge of a flexible spiral carrier. This allows the stimulation contacts to form a 360-degree surround coverage of the fibers within the nerve bundle after implantation, providing a structural basis for precise stimulation of target fibers from multiple spatial orientations. Furthermore, by configuring the stimulation contacts to be oriented to expose only towards the inner or lateral side of the spiral, while the back is covered with an insulating layer, ineffective leakage of current to the outside of the nerve bundle is effectively reduced, improving the focusing of the current field. Based on this hardware, the spatiotemporal coordinated selective neuromodulation system of the aforementioned embodiments independently controls the discharge time, discharge intensity, and waveform of each contact through a multi-channel pulse generator. Spatially, it executes an anodic blocking strategy to form a virtual anodic barrier along the sensory fiber path; temporally, it outputs quasi-trapezoidal waves or asymmetric biphasic waves optimized for motor fibers to utilize the temporal differences between motor and sensory fibers to amplify the activation threshold gap. The synergistic effect of spatial and temporal dimensions enables the system to "carve" a highly controllable current field in shape, direction, and intensity within the nerve bundle, precisely focusing the stimulation current onto the target motor fiber to reach its activation threshold, while keeping adjacent sensory fibers in a weak zone of the current field and thus achieving a painless selective stimulation effect where motor fibers are activated while sensory fibers are not.

[0125] Furthermore, by using medical-grade silicone or liquid silicone with a low Young's modulus to create a flexible helical carrier, its mechanical properties closely resemble those of nerve tissue. After implantation, the electrode can move, bend, and deform slightly along with the nerve, significantly reducing friction, shearing, and compression between the electrode and fragile nerve tissue, fundamentally lowering the risk of chronic injury, inflammation, and fibrosis. Optionally, by designing the flexible helical carrier as a variable-pitch structure with smaller pitch at both ends than in the middle, the electrode ends gain stronger anchoring ability to prevent axial slippage, while the middle portion maintains better flexibility to adapt to the bending movements of the nerve, achieving a balanced optimization of positioning stability and mechanical compliance.

[0126] Furthermore, by applying a low-resistance coating made of titanium nitride or platinum black to the surface of the stimulation contact, the electrode-tissue interface impedance is reduced, the charge injection efficiency is improved, which helps to reduce the voltage amplitude required for stimulation, reduce the occurrence of electrochemical side reactions, and improve the safety and effectiveness of stimulation.

[0127] Furthermore, by combining and controlling multiple adjacent stimulation contacts to form virtual contacts, and by adjusting the current ratio of each contact to precisely guide the shape and direction of the current field, the system can achieve a finer spatial resolution than the spacing between physical contacts even if the position of the physical contacts is fixed. This further enhances the system's ability to regulate the current field and precisely activate the target nerve fibers.

[0128] It should be noted that in this patent application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0129] All documents mentioned in this application are considered to be incorporated in their entirety into the disclosure of this application so that they can serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A flexible helical bundle inner electrode with a stress-buffering structure, characterized in that, include: The flexible helical carrier is made of biocompatible elastic material, has a preset three-dimensional helical shape, and has a cavity along its central axis for accommodating temporary support rods. A three-dimensional contact array, comprising multiple stimulation contacts distributed on the surface of the flexible helical carrier; The stress-buffered interconnecting wire includes multiple conductive traces integrated on the flexible spiral carrier, the conductive traces respectively connecting the stimulation contact and the external interface; The conductive traces are geometrically serpentine, S-shaped, or wavy, and are configured to release stress and maintain electrical continuity when the flexible helical carrier undergoes axial stretching or bending deformation by unfolding its geometric shape.

2. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, Each stimulation contact in the three-dimensional contact array is configured to be exposed only toward the inside or side of the flexible helical carrier, and the back of the stimulation contact is covered with an insulating layer to reduce current leakage out of the nerve bundle.

3. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, The plurality of stimulation contacts are distributed along the spiral ridge of the flexible spiral carrier, forming a 360-degree surround coverage of the internal fibers of the nerve bundle.

4. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, The flexible helical carrier has a variable pitch feature, wherein the pitch at both ends of the flexible helical carrier is smaller than the pitch in the middle part, presenting a structure that is dense at both ends and sparse in the middle.

5. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, The linewidth of the conductive trace is 10-50µm, the amplitude of the meandering geometry is 50-200µm, and the wavelength is 100-500µm.

6. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, The flexible helical carrier is in the shape of a helical column with an outer diameter of 0.5-2.0 mm, a pitch of 0.5-3.0 mm, and 3-8 helical turns; the diameter of the lumen is 100-300 µm.

7. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, The biocompatible elastic material is medical-grade silicone or liquid silicone (LSR) with a Young's modulus of less than 1 MPa; the impedance of the stimulation contact is 1-20 kΩ, and the surface is provided with a low-impedance coating, the low-impedance coating material being selected from titanium nitride (TiN) or platinum black (Pt-Black).

8. The flexible helical bundle inner electrode with stress-buffering structure as described in claim 1, characterized in that, It also includes a temporary support rod, which is removably inserted into the lumen and configured to provide temporary rigidification support for the flexible helical carrier during implantation.

9. A spatiotemporal coordinated selective neural modulation system, characterized in that, include: Flexible helical bundle inner electrode with stress-buffering structure as described in any one of claims 1 to 8; as well as A multi-channel pulse generator is connected to multiple stimulation contacts of the inner electrode of the flexible spiral bundle, and is configured to independently control the discharge time, discharge intensity and waveform of each stimulation contact.

10. The spatiotemporal coordinated selective neural modulation system as described in claim 9, characterized in that, The multichannel pulse generator is configured to execute an anode blocking strategy, which forms a virtual anode barrier along the sensory fiber pathway by applying an inhibitory current at selected anode contacts to inhibit the activation of sensory nerves.

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