Rigid-flexible interconversion neural electrode and rigidity change control method thereof

Abstract

The invention discloses a rigid-flexible interconversion neural electrode and a rigidity change control method thereof, and belongs to the technical field of neural electrodes, the rigid-flexible interconversion neural electrode comprises a neural electrode body, and the neural electrode body is composed of electrical stimulation modules and split insulation units which are arranged in a staggered manner; a wire is arranged in the neural electrode body, one end of the wire is connected with an external signal controller, and the other end of the wire is connected with the electrical stimulation module; the split insulation units are arranged around the wire, the split insulation units are in a hollow state when no medium is injected into the split insulation units, and flexible electric field generating lines are arranged in the split insulation units. The rigidity can be adjusted according to needs, the implantation precision is guaranteed, meanwhile, abrasion to brain tissue is avoided, the inflammatory reaction of the tissue is relieved, the treatment effect is improved, the working life of the neural electrode is greatly prolonged, when the electrode shifts, the position can be accurately adjusted again in the cranium, a secondary operation is avoided, and the body pain of a patient is relieved; the economic pressure of patients is relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of neural electrodes, and particularly to a rigid-flexible transformable neural electrode and a method for controlling its stiffness change. Background Art

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] As a new type of medical device, the role of neural electrodes is mainly to record, stimulate, and regulate neural activities. By directly contacting neural tissues, they can real-time obtain the electrical signals of the brain, spinal cord, and other neural tissues, and perform accurate stimulation to regulate abnormal neural electrical activities, so as to achieve the purpose of treating diseases, namely deep brain stimulation (DBS).

[0004] DBS is an important means for treating mid- and late-stage neurodegenerative diseases. However, due to the long-term relative movement between the brain tissue suspended in cerebrospinal fluid and the rigid electrode, tissue abrasion occurs, triggering an inflammatory response, and then leading to gliosis and the failure of electrical stimulation treatment. Flexible electrodes can be suspended in cerebrospinal fluid together with the brain tissue, avoiding the relative sliding between the electrode and the tissue and reducing the abrasion of the electrode on the brain tissue. Therefore, the flexibility of the implanted electrode is an effective means to reduce the inflammatory response and improve the working life of the electrode. However, due to the small stiffness of the flexible electrode, it is difficult to accurately implant it into the deep brain target position; in addition, when the electrode is displaced or the lesion is offset, a second operation must be performed to re-implant it, so its application in the process of deep brain stimulation treatment is limited. Summary of the Invention

[0005] Aiming at the above problems, the present invention proposes a rigid-flexible transformable neural electrode and a method for controlling its stiffness change. Its stiffness can be adjusted as needed, which can avoid abrasion of the brain tissue while ensuring the implantation accuracy, relieve the inflammatory response of the tissue, improve the treatment effect, greatly improve the working life of the neural electrode. When the electrode is displaced, it can accurately adjust the position in the cranial cavity again, avoiding a second operation, relieving the physical pain of the patient, and reducing the economic pressure on the patient.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect of the present invention, a rigid-flexible transformable neural electrode is provided, including a neural electrode body, and the neural electrode body is composed of alternately arranged electrical stimulation modules and split insulation units;

[0008] A wire is arranged inside the neural electrode body, one end of the wire is connected to an external signal controller, and the other end is connected to the electrical stimulation module;

[0009] The split insulation unit is arranged around the wire and is in a hollow state when no medium is injected inside. A flexible electric field generating wire is arranged inside the split insulation unit.

[0010] As a further implementation manner, the split insulation unit is prepared from an insulating and biocompatible flexible material.

[0011] As a further implementation manner, a liquid or gas medium can be injected inside the split insulation unit.

[0012] As a further implementation manner, the adjustable range of the diameter of the split insulation unit is 10 μm - 500 μm.

[0013] As a further implementation manner, the flexible electric field generating wire is connected to a signal generator, and electric fields with different intensities are generated by regulating electric signals.

[0014] As a further implementation manner, the split insulation unit is axially divided along the wire into a plurality of independent regions, and a medium can be injected into each independent region.

[0015] As a further implementation manner, there is at least one electric stimulation module, and its position is not completely limited to the end of the nerve electrode.

[0016] As a further implementation manner, the electric stimulation module is the discharge region of the nerve electrode body and is composed of an inert metal or alloy.

[0017] As a further implementation manner, the diameter of the wire is between 100 nm and 100 μm, and the diameter of the flexible electric field generating wire is between 10 μm and 150 μm.

[0018] In the second aspect of the present invention, a method for controlling the stiffness change of a rigid-flexible transformable nerve electrode is provided. Based on the rigid-flexible transformable nerve electrode described in the first aspect of the present invention, the method includes the following steps:

[0019] According to the elastic modulus of the brain tissue, the elastic modulus of ice, and the implantation depth, combined with the stiffness calculation formula, calculate the cross-sectional area required for the nerve electrode to accurately implant at the target position, and then obtain the cross-sectional diameter of the nerve electrode, and further obtain the injection amount of the liquid medium;

[0020] According to the mathematical model of the electric field intensity and the freezing point of the medium, calculate the electric field intensity range, and change the electric field intensity of the flexible electric field generating wire by regulating the voltage to promote the injected medium column to solidify to the required stiffness within the appropriate temperature range of the human tissue;

[0021] When the electrode enters the preset coordinates and works smoothly, the power supply of the flexible electric field generating line is disconnected to melt the icicle, discharge the medium in the split insulating unit, reduce its diameter, and make the neural electrode further miniaturized and flexible;

[0022] When the lesion area shifts and the electrode position needs to be readjusted, the medium is injected into the hollow part of the split insulation unit again, and the voltage value is adjusted at the same time so that the flexible electric field generating line generates a corresponding electric field strength, so that the medium solidifies, the rigidity of the flexible electrode is increased, and the electrode position is adjusted.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. A rigid-flexible neural electrode of the present invention designs the implanted electrode into a structure with adjustable stiffness, which can conveniently realize the rigid-flexible transition of the electrode. It has rigidity during the implantation process to ensure the implantation accuracy, and is transformed into flexibility after implantation, so that it can drift synchronously with the brain tissue to avoid its wear on the brain tissue, thereby greatly alleviating the inflammatory response of the tissue, improving the treatment effect, and greatly improving the working life of the neural electrode; and when the electrode is displaced, its stiffness can be increased to temporarily transform it into a rigid electrode, so as to facilitate precise adjustment of the position in the skull, avoid secondary surgery, relieve the patient's physical pain, and reduce the patient's economic pressure.

[0025] 2. The rigid-flexible neural electrode of the present invention replaces the traditional rigid deep brain implant electrode, avoiding the relative movement between the rigid electrode and the brain tissue during daily activities, which is beneficial to alleviate brain tissue wear, reduce brain tissue inflammatory response, promote nerve cell proliferation and differentiation, and improve electrode biocompatibility.

[0026] 3. The rigid-flexible neural electrode of the present invention eliminates the electrode sleeve required for traditional deep brain implant surgery. While ensuring the treatment effect, it reduces the diameter of the implanted electrode, which is conducive to minimally invasive implantation, can effectively alleviate the patient's pain, and reduce the risk of puncturing cerebral blood vessels during surgery.

[0027] 4. The rigid-flexible neural electrode of the present invention temporarily improves the rigidity of the flexible electrode mainly by solidifying the icicle of the insulating unit. By applying an additional electric field to the water column in the insulating chamber to control the freezing point of the water column, it not only solves the problem that water is difficult to solidify in the warm environment of the cranial cavity, but also ensures that the warm icicle will not cause tissue frostbite, thus ensuring the safety of the operation. In addition, water is an important part of the human body, and even if the hollow area is broken, it will not damage the tissue, further ensuring the safety of the operation.

[0028] 5. A rigid-flexible transformable nerve electrode of the present invention has a large water injection volume in multiple split insulating units surrounding the wire, an adjustable icicle diameter, and can further increase the freezing point of the liquid medium by increasing the electric field strength, so that at body temperature, the icicle has a higher elastic modulus and greater stiffness. Therefore, the adjustable range of the icicle stiffness is wide, and it has a wide range of application scenarios for various minimally invasive puncture and implantation scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0030] Figure 1 is a schematic diagram of the overall structure of the rigid-flexible transformable nerve electrode of the present invention;

[0031] Figure 2 is Figure 1 a sectional view taken along the direction of A-A;

[0032] Figure 3 is Figure 1 a sectional view taken along the direction of B-B.

[0033] Among them, 1. wire; 2. split insulating unit; 3. electrical stimulation module; 4. flexible electric field generating wire; 5. medium. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0035] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0036] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0037] Embodiment 1

[0038] As Figures 1-3 shown, this embodiment provides a rigid-flexible transformable nerve electrode, including a nerve electrode body, and the nerve electrode body is composed of alternately arranged electrical stimulation modules 3 and split insulating units 2;

[0039] A wire 1 is arranged inside the nerve electrode body, one end of the wire 1 is connected to an external signal controller, and the other end thereof is connected to the electrical stimulation module 3;

[0040] The split insulation unit 2 is arranged around the wire 1 and is in a hollow state when no medium 5 is injected into it (for the convenience of description, water is used as the medium in this embodiment). A flexible electric field generating wire 4 is arranged inside the split insulation unit 2.

[0041] In this embodiment, the electrical stimulation module 3 is cylindrical and mainly provides a continuous and stable specific frequency electrical signal for the target nucleus to improve the symptoms of the patient. The wire 1 is used to connect to an external signal controller to transmit electrical signals for electrical stimulation treatment.

[0042] The split insulation unit 2 is a hollow strip-shaped structure. A flexible electric field generating wire 4 is placed in the internal hollow structure. The flexible electric field generating wire 4 is respectively connected to a power supply and an external signal controller and is used to generate electric fields of different intensities to adjust the freezing point of the water column injected into the hollow area.

[0043] The split insulation unit 2 is made of a flexible material and has good biocompatibility to ensure that the electrode stiffness will not increase when no water is injected; the material of the split insulation unit 2 has good insulation properties to completely confine the generated electric field within the hollow area to ensure the safety of the brain tissue. A liquid or gas medium 5 can be injected into the split insulation unit 2. In this embodiment, water is used as the injected medium to explain the structure and usage method of the neural electrode of the present invention.

[0044] The split insulation unit 2 is axially divided into multiple independent regions along the wire 1, and each of the independent regions can be injected with the medium 5. The adjustable range of the diameter of the split insulation unit 2 is 10 μm - 500 μm.

[0045] The flexible electric field generating wire 4 is connected to a signal generator, and electric fields of different intensities are generated by regulating the electrical signal.

[0046] There is at least one electrical stimulation module 3, and its position is not completely limited to the end of the neural electrode. The electrical stimulation module 3 is arranged at the end part of the neural electrode body or at several discharge parts above 1 / 3 - 2 / 3. Setting multiple electrical stimulation modules 3 on the electrode body can cover targets at different brain depths (such as STN and Gpi targets), and the symptoms of neurodegenerative diseases can be improved synchronously through heterogenous frequency or ectopic stimulation; in addition, multi-target collaborative intervention can broaden the regulation range of electrical stimulation treatment, which is convenient for doctors to flexibly switch contacts according to the disease progression and extend the working life of the device.

[0047] The electrical stimulation module 3 is the discharge area of the neural electrode body and is composed of an inert metal or alloy, including but not limited to Au, Ag, W, Pt, Ir, and Pt-Ir alloy, etc.

[0048] The diameter of the wire 1 is between 100 nm and 100 μm, and the diameter of the flexible electric field generating wire 4 is between 10 μm and 150 μm.

[0049] The rigid-flexible transformable nerve electrode of the present invention divides the insulating area of the traditional electrode along the axial direction into multiple independent areas, and sets the multiple independent areas into a hollow structure with a flexible electric field generating wire 4 placed inside the hollow (as Figure 2 shown). Without changing the macroscopic size of the electrode, the stiffness of the implanted electrode is adjusted by forming icicles with different diameters in the hollow area, so that the electrode has the characteristics of high stiffness during the implantation process, which is convenient for accurately implanting the electrode into the preset position.

[0050] When the electrode enters the preset coordinates and operates stably, disconnect the electric field generating wire 4 to melt the icicle, drain the water column in the hollow area of the insulating part, reduce the diameter of the insulating area, miniaturize and flexibilize the nerve electrode further, reduce its abrasion to the brain tissue, and then relieve the inflammatory reaction and improve the working life of the electrode.

[0051] Among them, the specific operation of injecting or draining the water column in the hollow area of the insulating part is as follows: there is an opening at the top of the hollow part of each split insulating unit 2, which can be opened, and a micro syringe is used to inject liquid along the opening. After the electrode operates stably, the liquid is drawn out of the body through the syringe from the opening.

[0052] When the lesion area shifts and the electrode position needs to be adjusted again, there is no need for a second craniotomy. Only liquid water needs to be injected into the hollow part of the split insulating unit 2, and at the same time, the voltage value is regulated to make the flexible electric field generating wire 4 generate an electric field with an intensity of E, change the potential energy distribution between water molecules, and then increase the freezing point of water, so that the water column solidifies at room temperature to form an icicle, and then increase the stiffness of the flexible electrode. Since there are multiple independent partitions in the split insulating unit 2 around the wire (as Figure 2 ), and each independent partition can form an icicle, the adjustable range of the stiffness of the flexible electrode is wide, which is very convenient for adjusting the subsequent electrostimulation position, avoiding the need to re-implant with a rigid cannula for a second time, and reducing the pain and economic pressure of the patient.

[0053] Embodiment 2

[0054] As Figure 2 shown, this embodiment provides a method for controlling the stiffness change of a rigid-flexible transformable nerve electrode, based on a rigid-flexible transformable nerve electrode in Embodiment 1.

[0055] According to the elastic modulus of the brain tissue, the elastic modulus of ice and the implantation depth, combined with the stiffness calculation formula, calculate the cross-sectional area required for the nerve electrode to be accurately implanted into the target position, and then obtain the cross-sectional diameter of the nerve electrode, and then obtain the injection volume of the liquid medium;

[0056] The electric field intensity range is calculated based on the mathematical model of electric field intensity and the solidification point of the medium, and the electric field intensity of the flexible electric field generating line is changed by adjusting the voltage to promote the injected medium column to solidify to the required stiffness within the temperature range suitable for human tissue;

[0057] When the electrode enters the preset coordinates and works smoothly, the power supply of the flexible electric field generating line is disconnected to melt the icicle, discharge the medium in the split insulating unit, reduce its diameter, and make the neural electrode further miniaturized and flexible;

[0058] When the lesion area shifts and the electrode position needs to be readjusted, the medium is injected into the hollow part of the split insulation unit again, and the voltage value is adjusted at the same time so that the flexible electric field generating line generates a corresponding electric field strength, so that the medium solidifies, the rigidity of the flexible electrode is increased, and the electrode position is adjusted.

[0059] The specific calculation process is as follows:

[0060] First, the elastic modulus E of brain tissue is known. 脑 , implantation depth h, and elastic modulus of ice E 冰 , then the required stiffness k for implanted electrodes e It can be expressed as: Where A is the cross-sectional area of ​​the electrode, d is the required electrode diameter, and since the electrode cross-section is not a standard circle, a shape correction factor m is introduced. To ensure that the electrode does not flex during implantation, the electrode axial stiffness is balanced with the equivalent stiffness of the brain tissue in the implantation area, and we get The required electrode diameter can be obtained by combined solution: The amount of liquid medium injected can then be obtained.

[0061] Secondly, a mathematical model ΔT = k·E was constructed between the water freezing point increase ΔT and the applied electric field strength E. n , where k is the proportionality constant and n is the power exponent.

[0062] Secondly, under normal conditions, the freezing point of water is 0℃, that is, 273k. In order to avoid frostbite of brain tissue, it is necessary to ensure that the freezing point of water is raised by ΔTk to ensure that the water injected into the hollow area can solidify at a temperature suitable for the human body (that is, 309-311k). The field strength range can be calculated by combining the field strength and the mathematical model of the freezing point of water. By regulating the intensity of the electric field, the injected water column is promoted to solidify at a temperature comfortable for the human body, so that the flexible electrode has temporary rigidity, ensuring precise implantation of the electrode.

[0063] Secondly, by adjusting the voltage to change the electric field strength, the injected water column is promoted to solidify in a temperature range suitable for human tissue, so that the flexible electrode has temporary rigidity and ensures precise implantation of the electrode.

[0064] Secondly, at T °C, the mathematical model of the elastic modulus of ice is: E(T) = E0(1 - α(T - T0)), where T0 is the freezing point of ice, E0 is the elastic modulus corresponding to the freezing point, and the temperature coefficient α ≈ 0.0045 °C -1 According to the mathematical model, by continuously increasing the electric field, the freezing point of water can be made much higher than the temperature suitable for the tissue, that is, making T0 much higher than T. As a result, the liquid column forms a more "compact" ice column with a higher elastic modulus in the temperature range suitable for the human body, and thus has a greater stiffness under the same diameter. Therefore, without increasing the diameter of the liquid column, the overall stiffness of the electrode can be increased, and the implantation trauma can be reduced.

[0065] Secondly, when the electrode is implanted into the target target, since the brain tissue is in a suspended state, reducing the rigidity of the electrode is beneficial to keeping the electrode and the tissue drift synchronously. Therefore, by simply stopping the electric field, the ice column can be naturally melted, and then the water can be drained to convert the rigid electrode into a flexible one.

[0066] Secondly, during the long-term treatment process, due to the micro-offset of the lesion and the low stiffness of the flexible electrode, the coordinates of the electrical stimulation area cannot be finely adjusted. At this time, only need to inject a water column into the hollow part of the split insulation unit, and adjust the electric field strength again to make the liquid column solidify into an ice column again in the temperature range suitable for the human body, improve the stiffness of the electrode, and convert the flexible electrode into a rigid electrode, which is convenient for medical staff to adjust the position of the electrode.

[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0068] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made without creative labor by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A rigid-flexible transformable neural electrode, characterized in that, It includes a neural electrode body, which is composed of staggered electrical stimulation modules and split insulation units; A wire is provided inside the neural electrode body, one end of the wire is connected to the external signal controller, and the other end of the wire is connected to the electrical stimulation module; The split insulating unit is arranged around the conducting wire and is in a hollow state when no medium is injected into the interior thereof. A flexible electric field generating wire is arranged inside the split insulating unit.

2. The flexible-rigid transformable nerve electrode according to claim 1, wherein The split insulating unit is made of insulating, biocompatible flexible material.

3. The flexible-rigid interconverting nerve electrode according to claim 2, wherein Liquid or gas medium may be injected into the split insulation unit.

4. The flexible-rigid transformable neural electrode according to claim 1, wherein The diameter of the split insulation unit can be adjusted in the range of 10 μm to 500 μm.

5. A rigid-flexible interconverting nerve electricity as described in claim 1, characterized in that, The flexible electric field generating wire is connected to a signal generator and generates electric fields of different intensities by regulating the electric signal.

6. The flexible-rigid transformable neural electrode according to claim 1, wherein The split insulation unit is divided into a plurality of independent regions along the axial direction of the conductor, and each of the independent regions can be injected with a medium.

7. The flexible-rigid convertible nerve electrode according to claim 1, wherein There is no less than one electrical stimulation module, and the location is not completely limited to the end of the nerve electrode.

8. The flexible-rigid transformable neural electrode according to claim 1, wherein The electrical stimulation module is the discharge area of ​​the neural electrode body and is composed of an inert metal or alloy.

9. The flexible-rigid convertible neural electrode according to claim 1, characterized in that, The diameter of the conductive wire is between 100 nm and 100 μm, and the diameter of the flexible electric field generating wire is between 10 μm and 150 μm.

10. A method for controlling the stiffness change of a rigid-flexible transformable neural electrode, characterized in that, A rigid-flexible neural electrode according to any one of claims 1 to 9 comprises the following steps: According to the elastic modulus of brain tissue, the elastic modulus of ice and the implantation depth, combined with the stiffness calculation formula, the cross-sectional area required for the accurate implantation of the neural electrode at the target position is calculated, and then the cross-sectional diameter of the neural electrode is obtained, and then the amount of liquid medium injected is obtained; The electric field intensity range is calculated based on the mathematical model of electric field intensity and the solidification point of the medium, and the electric field intensity of the flexible electric field generating line is changed by adjusting the voltage to promote the injected medium column to solidify to the required stiffness within the temperature range suitable for human tissue; When the electrode enters the preset coordinates and works smoothly, the power supply of the flexible electric field generating line is disconnected to melt the icicle, discharge the medium in the split insulating unit, reduce its diameter, and make the neural electrode further miniaturized and flexible; When the lesion area shifts and the electrode position needs to be readjusted, the medium is injected into the hollow part of the split insulation unit again, and the voltage value is adjusted at the same time so that the flexible electric field generating line generates a corresponding electric field strength, so that the medium solidifies, the rigidity of the flexible electrode is increased, and the electrode position is adjusted.

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