Electrical conductor and preparation method thereof and implantable biological electrode

Abstract

The present invention provides an electrical conductor and a preparation method thereof and an implantable bioelectrode, which can make the implantable bioelectrode have corresponding stiffness in different sections, thereby improving the success rate of electrical stimulation treatment and the reliability of circuit connection. The implantable bioelectrode of the present invention includes an electrical conductor, and the electrical conductor includes a spiral conductive body, the conductive body at least has a distal section, a middle section and a proximal section connected in sequence, and the stiffness of the middle section is less than the stiffness of the distal section and the proximal section. In actual preparation, the conductive body can be formed by spirally cutting a metal tube, which simplifies the preparation process and effectively controls the stiffness of each section.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an electric wire and a preparation method thereof and an implantable biological electrode. Background Art

[0002] With the development of modern medical technology, more and more diseases that traditional medicine cannot treat can be treated through electrical stimulation technology. For example, electrical stimulation of the myocardium can treat abnormal heart rate, electrical stimulation of the subthalamic nucleus or internal globus pallidus can improve Parkinson's symptoms, and electrical stimulation of the vagus nerve can assist in the treatment of drug-resistant epilepsy and depression. Electrical stimulation therapy improves symptoms and treats diseases by injecting electric charges into muscles or nerve cells. The devices used usually include a pulse generator and a biological electrode (hereinafter referred to as an electrode) implanted in the human body. The pulse generator generates an electrical signal, which reaches the electrode after a certain conduction path, and the electrode transmits the electrical signal to the target. Therefore, as an important component of the electrical stimulation system, the implantable electrode plays a role in interacting with human tissue. Research on the design and manufacture of electrodes is of great significance to the effectiveness and safety of the entire electrical stimulation system.

[0003] Current electrical stimulation systems used for deep brain stimulation (DBS) include Figure 1a As shown, it includes a pulse generator (usually abbreviated as IPG) 1, an electrode extension line 2 and an electrode 3. The pulse generator 1 is implanted in the chest cavity, the pulse generator 1 is connected to the proximal end of the electrode extension line 2, the electrode extension line 2 is buried under the human skin, passes through the neck to reach the surface of the skull, the distal end of the electrode extension line 2 is connected to the proximal end of the electrode 3, the electrode 3 passes through the skull and is inserted into the brain, the distal end of the electrode 3 contacts the target point, the electrode 3 is fixed at the skull perforation through the skull cap 4, the pulse signal generated by the pulse generator 1 is transmitted to the electrode 3 through the electrode extension line 2, and then transmitted to the target point.

[0004] The electrodes currently used for DBS are usually Figure 2a The structure shown. The main structure of the electrode is a slender polymer plastic tube, called an electrode catheter 33; a number of metal rings are installed at the ends of the electrode catheter 33; the distal end is called the stimulation electrode ring 31, which plays the role of injecting electric charge into biological tissue to generate electrical stimulation; the proximal end is called the connecting electrode ring 32, which plays the role of connecting the electrode extension line to the circuit; the inside of the electrode catheter 33 is penetrated by an electric wire 34, which is used to connect the stimulation electrode ring 31 and the connecting electrode ring 32 at the end to form a conductive channel. The material of the electrode catheter 33 is usually a polymer with good biocompatibility such as polyurethane or silicone rubber, with low hardness, similar to rubber, and the material of the stimulation electrode ring 31 and the connecting electrode ring 32 is usually precious metal (such as platinum-iridium alloy) and nickel-cobalt alloy (such as MP35N), etc., with good corrosion resistance and biocompatibility.

[0005] like Figure 2bAs shown, the conventional electrical conductor 34 is spiral-shaped and is wound by a plurality of uniform guide wires 34-2. The surface of the guide wire 34-2 is provided with an insulating coating 34-1, and the number of the guide wires 34-2 is equal to the number of the stimulation electrode rings 31 or the connecting electrode rings 32, thereby ensuring that each stimulation electrode ring 31 is connected to the corresponding connecting electrode ring 32 through an independent conductive channel. The guide wire used to make the electrical conductor 34 is usually circular in cross-section and wound into a spiral. The guide wire is usually a platinum-iridium alloy or MP35N. Each guide wire is insulated from each other by a coating, and the coating is usually PTFE, ETFE or PFA, etc. The spiral conductor can ensure that the electrode has good mechanical flexibility, because the electrode needs to withstand various complex forces during installation or use. As Figure 1b As shown, the electrode can be divided into four sections according to the different forces on the electrode: the first section is the intracranial section 301, which is inserted into the brain tissue; the second section is the transcranial section 302, which is connected to the skull cap, where the electrode is bent into a certain angle and fixed to the skull through the skull cap 4 to ensure that the stimulation electrode ring at the distal end of the electrode does not shift, because the displacement of the stimulation electrode ring 31 may cause the stimulation to fail; the third section is the transition section 303, which is longer, and the electrode is coiled into one or several circles and placed in the scalp outside the skull; the fourth section is the connecting section 304, which is inserted into the electrode extension line to connect the circuit.

[0006] However, the existing electrodes used for DBS have uniform overall rigidity and are relatively small relative to the actual force requirements, which can easily cause electrode displacement and lead to treatment failure. It is also inconvenient to plug and unplug the proximal end of the electrode, and axial deformation is easily generated during plugging and unplugging, resulting in changes in the spacing between the connecting electrode rings, and is more likely to cause a short circuit in the electrode connection, affecting treatment. Summary of the invention

[0007] The object of the present invention is to provide an electrical conductor and a preparation method thereof and an implantable bioelectrode to solve the problem that the overall rigidity of the electrical conductor used for the existing bioelectrode is uniform and constant and the rigidity is relatively small relative to the actual force requirement.

[0008] To solve the above technical problems, the present invention provides an electrical conductor, which includes a spiral conductive body, wherein the conductive body has at least a distal segment, a middle segment and a proximal segment connected in sequence, wherein the stiffness of the middle segment is smaller than the stiffness of the distal segment and the proximal segment.

[0009] Preferably, the helical cross-sectional width of the middle section is smaller than the helical cross-sectional widths of the distal section and the proximal section, and / or the helical pitch of the middle section is smaller than the helical pitches of the distal section and the proximal section.

[0010] Preferably, the conductive body is formed by spirally cutting a metal tube.

[0011] Preferably, the middle section includes a plurality of sub-sections connected in sequence, and the stiffness of one of the sub-sections connected to the distal section is smaller than the stiffness of the other sub-sections.

[0012] Preferably, there are two subsections.

[0013] Preferably, the stiffness of the proximal section is greater than the stiffness of the distal section.

[0014] Preferably, the outer surface of the conductive body is covered with an insulating layer.

[0015] Preferably, the conductive body is a spiral circular tube.

[0016] Preferably, the spiral cross-section of the conductive body is rectangular, parallelogram or trapezoidal.

[0017] In order to solve the above technical problems, the present invention also provides an implantable bioelectrode, which includes the above-mentioned electrical conductor.

[0018] Preferably, the implantable bioelectrode further comprises an electrode catheter, the electrical conductor is inserted into the electrode catheter, and two ends of the electrical conductor are electrically connected to two ends of the electrode catheter respectively.

[0019] In order to solve the above technical problems, the present invention also provides a method for preparing an electric conductor, which comprises:

[0020] A metal tube is cut into a spiral structure along a specified path to obtain a conductive body, wherein the conductive body has at least a distal section, a middle section and a proximal section connected in sequence, wherein the stiffness of the distal section and the proximal section is greater than the stiffness of the middle section.

[0021] Preferably, after obtaining the conductive body, the preparation method further comprises:

[0022] The conductive body is sequentially subjected to surface pickling, polishing and insulation treatment.

[0023] Preferably, the designated path includes a cutting path formed based on the spiral cross-sectional width of the middle segment being smaller than the spiral cross-sectional widths of the distal segment and the proximal segment; and / or includes a cutting path formed based on the spiral pitch of the middle segment being smaller than the spiral pitch of the distal segment and the proximal segment.

[0024] Preferably, the step of insulating the conductive body comprises:

[0025] An insulating material is sprayed or dipped onto the conductive body to cover an insulating layer on the outer surface of the conductive body.

[0026] Preferably, the step of insulating the conductive body comprises:

[0027] The conductive body is co-extruded with an insulating material to cover an outer surface of the conductive body with an insulating layer.

[0028] Preferably, the metal tube is cut into the spiral structure along the specified path by laser cutting.

[0029] In the electric wire and its preparation method and implantable bio-electrode provided by the present invention, since the electric wire has different rigidity, especially the rigidity of the middle section is less than the rigidity of the distal section and the proximal section, the implantable bio-electrode such as DBS, spinal nerve stimulation, vagus nerve stimulation and the like electrodes using the electric wire is easy to bend and deform in the middle part during actual use, while the distal part has greater rigidity and is not easy to shift. In addition, the proximal part also has greater rigidity and is not easy to deform when plugging and unplugging with the electrode extension line, etc., so that the implantable bio-electrode can meet the rigidity requirements of different sections, so that the electrode is not easy to shift in the body, and it is also convenient to plug and unplug the electrode, so as not to cause a short circuit in the electrode connection. Therefore, the electric wire of the present invention can improve the success rate of electrical stimulation treatment and ensure the reliability of circuit connection.

[0030] In a preferred embodiment, the spiral cross-sectional width of the middle section is smaller than the spiral cross-sectional width of the distal section and the proximal section, so that the wire can obtain a larger spiral cross-sectional area in the proximal section and the distal section. In this case, since the resistance of the electrical conductor is inversely proportional to the spiral cross-sectional area and directly proportional to the length, when the length of the electrical conductor is constant, the total length of the conductor is reduced, and the impedance of the entire conductor is effectively reduced, which is beneficial to reducing the energy consumption of electrical stimulation therapy and increasing the service life of the electrode.

[0031] In a preferred embodiment, the conductive body is formed by spirally cutting a metal tube, and a spiral structure with a variable pitch and / or a variable cross-section can be obtained simply by controlling the parameters of the cutting seam. Not only is the preparation process simple, but it is also easy to control the stiffness of each section, and it is also convenient to flexibly configure the stiffness of the conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1a It is a schematic diagram of the installation of an existing electrical stimulation system for DBS in vivo;

[0033] Figure 1b It is a schematic diagram of the structure of an existing bioelectrode used for DBS;

[0034] Figure 2a It is a schematic diagram of the insertion of the electrical lead wire of the existing bioelectrode for DBS into the electrode catheter;

[0035] Figure 2b It is a schematic diagram of the electrical conductor of the existing bioelectrode used for DBS;

[0036] Figure 3 is a schematic structural diagram of an electrical conductor of a bioelectrode for DBS provided in an embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of a process for preparing an electrical conductor provided by an embodiment of the present invention.

[0038] In the figure,

[0039] Pulse generator 1; electrode extension line 2; electrode 3; intracranial section 301; transcranial section 302; transition section 303; connecting section 304; electrode catheter 33; stimulation electrode ring 31; connecting electrode ring 32; electric wire 34; coating 34-1; guide wire 34-2; skull cap 4;

[0040] Electrical conductor 340 ; intracranial section 341 ; transcranial section 342 ; transition section 343 ; connecting section 344 ; insulating layer 3401 ; spiral sections 3402 , 3402 ′; thin-walled tube 30 . DETAILED DESCRIPTION

[0041] In order to make the purpose, advantages and features of the present invention more clear, the medical tube and the preparation method thereof proposed by the present invention are further described in detail below in conjunction with specific drawings and embodiments. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0042] As used in this specification and the appended claims, the term "or" is generally used in a sense including "and / or", unless the content clearly indicates otherwise. In addition, in the following description, "distal" and "proximal" are used for ease of description; "proximal" is the side close to the operator of the medical device; "distal" is the end away from the operator of the medical device. In addition, in the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

[0043] Here, we first explain in detail the problems raised in the background technology and the core idea of ​​the present invention. As described in the background technology, the inventors found that the existing electrodes for DBS have the problem of uniform overall rigidity and low rigidity. The inventors further found that the electrical conductor 34 of the traditional electrode is wound by a uniform guide wire, and the cross-sectional area, cross-sectional shape and winding pitch d of the guide wire remain unchanged. Therefore, the mechanical properties of the electrical conductor 34 along the length direction are also unchanged, that is, the rigidity is uniform and unchanged, which is obviously inconsistent with the actual force requirements of the electrode.

[0044] For details, see Figure 1b and Figure 2a For the intracranial section 301 of the electrode, it is necessary to always keep the stimulation electrode ring 31 in the optimal stimulation area and not shift during the movement. Therefore, this section requires the electrode to have greater rigidity to prevent the electrode from being deformed and shifted by external force after implantation. For the transcranial section 302 of the electrode, it is necessary to bend the electrode at a larger angle, such as 90 degrees, and when bending, it is necessary to prevent the distal end of the electrode from being lifted by force, thereby causing the electrode to shift. Therefore, this section requires the electrode to have the minimum rigidity. In addition, for the transition section 303 of the electrode, which is the redundant length of the electrode, it is necessary to coil it around the outer surface of the skull. This section should have relatively small rigidity to facilitate coiling, and it can also buffer the large stress generated by the proximal end of the electrode after being pulled. This stress applied to the electrode may cause the electrode to break. Finally, for the connecting section 304 of the electrode, it is necessary to insert the electrode into the electrode extension line, so a larger rigidity is required to resist the plug-in and pull-out force. Therefore, DBS applications have different requirements for the rigidity of each segment of the electrode, but the electrode wires reported so far are not segmented, or the rigidity of each segment is consistent.

[0045] In addition, the inventors have also found that the stiffness of traditional electrodes is usually small. This is because the overall stiffness of traditional electrodes is uniform. For example, in DBS electrodes, since the electrode of the transcranial segment 302 needs to be bent at a large angle, in order to ensure that the distal end of the electrode does not shift after being subjected to force during bending, the rigidity needs to be designed to be very small. Since the rigidity is uniform, the overall rigidity of the electrode is relatively low.

[0046] Therefore, the overall rigidity of the traditional electrode is not only single and unchanged, but also relatively small relative to the actual force requirements. As a result, the following problems are prone to occur:

[0047] First, since the rigidity of the intracranial section 301 is relatively low, the electrodes of the intracranial section 301 are easily deformed by external forces, thereby causing the electrodes to shift and resulting in treatment failure.

[0048] Second, since the overall rigidity of the electrode is relatively low, a relatively rigid reinforcing core needs to be inserted into the electrode during the electrode implantation surgery to increase the overall rigidity of the electrode and resist the axial force applied to the electrode when it is inserted into the brain. Even so, since the axial rigidity of the electrode itself is relatively low, a certain residual strain will be generated during the implantation process, and the electrode will still shift to a certain extent after the reinforcing core is removed.

[0049] Third, due to the low rigidity of the connecting section 304, the proximal end of the electrode can usually only withstand an insertion and removal force of less than 1N, which is not convenient for the proximal end of the electrode to be inserted and removed. During insertion and removal, the electrode is prone to axial deformation, resulting in changes in the spacing between the connecting electrode rings. More seriously, it may also cause the electrode connection to be broken.

[0050] Based on the above research, the present invention proposes an electric wire, which is suitable for DBS electrodes but not limited thereto, and the electric wire includes a spiral conductive body, and the conductive body has at least a distal segment, an intermediate segment and a proximal segment connected in sequence, wherein the stiffness of the intermediate segment is less than the stiffness of the distal segment and the proximal segment. Preferably, the stiffness of the distal segment is less than the stiffness of the proximal segment. Therefore, the stiffness of the electric wire of the present invention is uneven as a whole, and has a minimum stiffness and a maximum stiffness, which facilitates the implantable bioelectrode using the electric wire to meet the mechanical requirements of different segments during use, thereby preventing the electrode from shifting, short-circuiting and other problems, and ensuring the normal use of the electrode.

[0051] Next, take the electrical conductor of the DBS electrode as an example. Figure 3 As shown, an electric wire 340 includes a spiral conductive body, and the conductive body includes four sections, which are, from far to near, an intracranial section 341, a transcranial section 342, a transition section 343, and a connecting section 344, which are connected in sequence. Here, it should be understood that the middle section of the present invention includes two sub-sections, namely, the transcranial section 342 and the transition section 343, and the intracranial section 341 constitutes the distal section of the present invention, and the connecting section 344 constitutes the proximal section of the present invention. Therefore, the intracranial section 341 is used to connect the stimulation electrode ring at the distal end of the DBS electrode catheter, and the connecting section 344 is used to connect the connecting electrode ring at the proximal end of the DBS electrode catheter, and the connection method is not limited to welding or bonding.

[0052] In some embodiments, the stiffness of the conductive body of the electric wire 340 is configured as follows: the transcranial section 342 < the transition section 343 < the intracranial section 341 < the connecting section 344, so the transcranial section 342 has the smallest stiffness, while the connecting section 344 has the largest stiffness. However, in other embodiments, the present invention does not limit the relative size of the stiffness of the intracranial section 341 and the connecting section 344, and the stiffness of the two can be the same or different. When the stiffness is different, the stiffness of the intracranial section 341 is smaller than the stiffness of the connecting section 344, or the stiffness of the intracranial section 341 can also be greater than the stiffness of the connecting section 344; and the present invention does not specifically limit the relative size of the stiffness of the transcranial section 342 and the transition section 343, and the stiffness of the two can actually be the same, which is specifically configured according to the force requirements of the electrode. Therefore, the present invention only needs to ensure that the stiffness of the transcranial section 342 and the transition section 343 are both smaller than that of the intracranial section 341 and the connecting section 344 .

[0053] Therefore, according to the different stress conditions of the DBS electrode, the stiffness of each section of the electrical conductor 340 is configured to be different, which can ensure that the DBS electrode can better cope with the stress of each section during use, prevent the electrode from shifting, avoid proximal short circuit of the electrode, and facilitate the plugging and unplugging of the proximal electrode.

[0054] More specifically, in the DBS electrode, the intracranial section 341 corresponds to the intracranial section 301 of the electrode. This part of the electrode needs to be inserted into the brain tissue, which can ensure that the stimulation electrode ring is always in the best stimulation area, and when the electrode is subjected to external force after implantation, the stimulation electrode ring is not easy to shift under the support of the greater rigidity of the intracranial section 341, so that it can better resist the external force. In addition, the transcranial section 342 corresponds to the transcranial section 302 of the electrode. This section of the electrode has less rigidity and can be bent to a greater extent to adapt to the morphology of the electrode after final implantation, and it is not easy to cause the distal end of the electrode to move when the electrode is bent. In addition, the transition section 343 corresponds to the transition section 303 of the electrode, has good flexibility, and can reduce the pulling on the intracranial electrode through its own deformation when the electrode is subjected to external force, thereby avoiding problems such as circuit disconnection caused by this. The connecting section 344 corresponds to the connecting section 304 of the electrode and has a relatively large rigidity. When the proximal end of the electrode is inserted into the electrode extension line, it can better resist the plugging and unplugging force, so that the electrode does not produce axial deformation during plugging and unplugging, thereby avoiding the change of the distance between the connecting electrode rings and preventing the electrode connection from short-circuiting. Therefore, the rigidity of the electric wire 340 of the embodiment of the present invention can meet these force requirements of the electrode, ensuring its reliability and effectiveness in use.

[0055] Furthermore, the conductive body of the electric wire 340 is preferably formed by spiral cutting of a metal thin-walled tube, and the metal thin-walled tube is preferably a round tube, and the outer diameter can be selected to be 0.8 mm, and the inner diameter can be 0.5 mm. Here, multiple independent spiral electric wires can be cut from the same metal thin-walled tube, which is convenient for manufacturing. In practice, the number of electric wires is consistent with the number of stimulation electrode rings or connection electrode rings, and the electric wires are insulated from each other.

[0056] Furthermore, the spiral cross section of the conductive body is a rectangle, a parallelogram or a trapezoid, and under a certain cross-sectional area, its fatigue strength is higher than that of the existing guide wire with a circular cross section. Here, the spiral cross section refers to the axial cross section of the spiral structure formed by spirally cutting the metal tube.

[0057] Furthermore, the material of the metal thin-walled tube is selected from biocompatible materials, and the material can be one or more combinations of materials such as platinum-iridium alloy, stainless steel, and MP35N. In addition, an insulating layer 3401 is formed on the outer surface of the conductive body, and the material of the insulating layer 3401 is selected from one or more combinations of materials such as PTFE, ETFE, and PFA, and the thickness of the insulating layer 3401 can be 0.025 mm. The insulating layer 3401 is used to electrically insulate the electrical conductors.

[0058] Furthermore, when spiral cutting a metal thin-walled tube, the cutting is performed along a specified path so that the stiffness of each section is different. The specified path includes different spiral cross-sectional widths of each section, or different pitches of each section, or different spiral cross-sectional widths and pitches of each section. Preferably, the spiral structure is obtained by laser cutting, which not only has high processing accuracy, but also can better control the stiffness of each section compared with the simple spiral winding method. Specifically, the spiral structure is obtained by spiral cutting a metal thin-walled tube, which is convenient for controlling the mechanical stiffness of the wire by controlling the cross-sectional size and pitch of the spiral structure in the wire, for example, using a large cross-sectional area and a large pitch to obtain greater mechanical stiffness, which is not only convenient for continuous production of pipes, but also convenient for good control of the stiffness of the pipes, and can also obtain wires with arbitrary parameters and performances, which is convenient for flexible configuration of the stiffness of the wire. Furthermore, since the resistance of the wire is inversely proportional to the cross-sectional area of ​​the conductor and directly proportional to the length, when the spiral structure of a certain section has a larger spiral cross-sectional area, the total length of the conductor (i.e., the spiral structure) can be reduced (i.e., the length of the conductor stretched into a straight state) when the length of the section is constant, which can effectively reduce the impedance of the entire wire and is beneficial to reducing the energy consumption of electrical stimulation therapy. Here, the spiral cross-sectional width refers to the cross-sectional size of the spiral structure in the axial direction of the metal tube.

[0059] and then Figure 3A preferred embodiment of the present invention is disclosed, in which the upper left corner partially enlarges four continuous spiral sections 3402 at the intracranial section 341, each spiral section 3402 has a width w and a pitch d, and at the same time Figure 3 The upper right corner partially enlarges four continuous spiral sections 3402 ′ at the transition section 343 , each of which has a width of w and a pitch of d.

[0060] like Figure 3 As shown, in a preferred embodiment, the spiral cross-sectional width w of the transcranial segment 342 is less than the spiral cross-sectional width w of the transition segment 343, less than the spiral cross-sectional width w of the intracranial segment 341, and less than the spiral cross-sectional width w of the connecting segment 344. At the same time, the pitch d of the transcranial segment 342 is less than the pitch d of the transition segment 343, less than the pitch d of the intracranial segment 341, and less than the pitch d of the connecting segment 344. However, it is not limited thereto. In other embodiments of the present invention, only the spiral cross-sectional width w of the transcranial segment 342 is less than the spiral cross-sectional width w of the transition segment 343, less than the spiral cross-sectional width w of the intracranial segment 341, and less than the spiral cross-sectional width w of the connecting segment 344, and the spiral pitch d of these segments is the same. Alternatively, in other embodiments of the present invention, only the spiral pitch d of the transcranial segment 342 is less than the pitch d of the transition segment 343, less than the pitch d of the intracranial segment 341, and less than the pitch d of the connecting segment 344, and the spiral cross-sectional width w of these segments is the same. It should be understood that the stiffness of the segment is positively correlated with the spiral cross-sectional width w and the pitch d. The larger the spiral cross-sectional width w and the pitch d, the greater the stiffness of the segment. Therefore, a larger spiral cross-sectional width and pitch can obtain greater mechanical rigidity.

[0061] Further, in an optional solution, the helical cross-sectional width and pitch of each section are set as follows:

[0062] Intracranial segment 341: The spiral section width and pitch are larger, the spiral section width w ranges from 0.5 to 1.0 mm, and the pitch d ranges from 0.51 to 1.01 mm;

[0063] Transcranial section 342: The spiral section width and pitch are small, the spiral section width w ranges from 0.15 to 0.19 mm, and the pitch d ranges from 0.16 to 0.2 mm;

[0064] Transition section 343: the spiral section width and the pitch are set to a medium size, the spiral section width w is in the range of 0.2 to 0.3 mm, and the pitch d is in the range of 0.21 to 0.31 mm;

[0065] Connecting section 344: The spiral section width and pitch are relatively large, the spiral section width w is in the range of 0.6 to 1.5 mm, and the pitch d is in the range of 0.61 to 1.51 mm, which can obtain relatively maximum mechanical rigidity.

[0066] Next, combine Figure 4 (a)- Figure 4 (c) further describes the preparation process of the electrical conductor 340 according to the embodiment of the present invention. Figure 4 As shown in (a)-(b), the preparation process of the electrical conductor 340 specifically includes:

[0067] First, Figure 4 As shown in (a), a platinum-iridium alloy thin-walled tube 30 is provided;

[0068] Secondly, Figure 4 As shown in (b), the platinum-iridium alloy thin-wall tube is laser cut into a spiral shape along a specified path to obtain a spiral original conductive body;

[0069] After that, the original conductive body is pickled, polished and insulated in turn, and finally obtained Figure 4 (c) shows a conductive body with an insulating layer on its surface. Among them, the residue formed by laser melting can be removed by pickling; and the polishing is preferably electrochemical polishing, which can remove burrs on the metal surface, make the metal surface smooth, and improve the fatigue life of the wire; the original conductive body after polishing is subjected to insulation treatment, such as spraying or dipping insulating material to insulate each electric wire, but the insulation treatment is not limited to spraying or dipping, and can also be achieved by co-extruding the polished original conductive body with the insulating material, so that the insulating material covers the surface of the conductive body.

[0070] It should be further explained that the preferred embodiments of the present invention are as described above, but are not limited to those disclosed in the above embodiments. For example, the segments included in the electric conductor are not limited to four, but may be three or more, which are mainly divided according to the stress conditions of the electrodes used in the electric conductor.

[0071] Finally, the embodiment of the present invention also provides an implantable bioelectrode, which is not limited to DBS electrodes, but can also be other electrodes, such as electrodes for spinal nerve stimulation and vagus nerve stimulation. The implantable bioelectrode of the present invention includes the electrical wire provided by the embodiment of the present invention.

[0072] Furthermore, the implantable bioelectrode of the embodiment of the present invention also includes an electrode catheter, in which an electric conductor is inserted, and the two ends of the electric conductor are respectively electrically connected to the two ends of the electrode catheter, such as electrode rings are respectively provided at the two ends of the electrode catheter, so that the two ends of the electric conductor are respectively connected to the electrode rings.

[0073] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An electrical conductor for deep brain stimulation, comprising a spiral conductive body, characterized in that: The conductive body has at least a distal segment, an intermediate segment and a proximal segment connected in sequence, wherein the stiffness of the intermediate segment is smaller than the stiffness of the distal segment and the proximal segment; the conductive body includes four segments, which are, from far to near, an intracranial segment, a transcranial segment, a transition segment and a connecting segment connected in sequence, the transcranial segment and the transition segment constitute the intermediate segment, the intracranial segment constitutes the distal segment, and the connecting segment constitutes the proximal segment; the spiral cross-sectional width of the intermediate segment is smaller than the spiral cross-sectional width of the distal segment and the proximal segment, and / or the pitch of the intermediate segment is smaller than the pitch of the distal segment and the proximal segment.

2. The electric conductor according to claim 1, characterized in that The conductive body is formed by spirally cutting a metal tube.

3. The electric conductor according to claim 1, characterized in that The middle section includes a plurality of sub-sections connected in sequence, and the stiffness of one of the sub-sections connected to the distal section is smaller than the stiffness of the other sub-sections.

4. The electric conductor according to claim 3, characterized in that There are two subsections.

5. The electric conductor according to claim 1, characterized in that The stiffness of the proximal section is greater than the stiffness of the distal section.

6. The electric conductor according to claim 1, characterized in that The outer surface of the conductive body is covered with an insulating layer.

7. The electric conductor according to claim 1, characterized in that The conductive body is a spiral round tube.

8. The electric conductor according to claim 1, characterized in that The spiral cross section of the conductive body is rectangular, parallelogram or trapezoidal.

9. An implantable bioelectrode, characterized in that: Comprising an electrical conductor according to any one of claims 1 to 8.

10. The implantable bioelectrode according to claim 9, characterized in that: It also includes an electrode catheter, the electric wire is inserted into the electrode catheter, and the two ends of the electric wire are electrically connected to the two ends of the electrode catheter respectively.

11. A method for preparing an electrical conductor for deep brain stimulation, characterized in that: include: Cutting a metal tube into a spiral structure along a specified path to obtain a conductive body, wherein the conductive body comprises four sections, which are, from far to near, an intracranial section, a transcranial section, a transition section and a connecting section, which are connected in sequence. The conductive body at least comprises a distal section, an intermediate section and a proximal section, which are connected in sequence. The stiffness of the distal section and the proximal section is greater than that of the intermediate section. The transcranial section and the transition section constitute the intermediate section, the intracranial section constitutes the distal section, and the connecting section constitutes the proximal section. Wherein, the designated path includes a cutting path formed based on the spiral cross-sectional width of the middle segment being smaller than the spiral cross-sectional widths of the distal segment and the proximal segment; and / or includes a cutting path formed based on the spiral pitch of the middle segment being smaller than the spiral pitch of the distal segment and the proximal segment.

12. The method for preparing an electric conductor according to claim 11, characterized in that: After obtaining the conductive body, the preparation method further comprises: The conductive body is sequentially subjected to surface pickling, polishing and insulation treatment.

13. The method for preparing an electric conductor according to claim 11 or 12, characterized in that: The step of insulating the conductive body comprises: An insulating material is sprayed or dipped onto the conductive body to cover an insulating layer on the outer surface of the conductive body.

14. The method for preparing an electric conductor according to claim 11 or 12, characterized in that: The step of insulating the conductive body comprises: The conductive body is co-extruded with an insulating material to cover an outer surface of the conductive body with an insulating layer.

15. The method for preparing an electric conductor according to claim 11, characterized in that: The metal tube is cut into the spiral structure along the specified path by laser cutting.

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