Methods to reduce electrode overflow

Abstract

A method for manufacturing an electrode assembly (20) includes the steps of: applying an electrode (24) onto a first material layer (22); laser welding a lead (23) to the electrode; applying an adhesive backfill (26) onto the electrode and the lead; and applying a second material layer (28) onto the adhesive backfill and a portion of the first layer to prevent leakage paths between the electrode and the second layer.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 846,546, filed May 10, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to the field of electrodes, and more particularly, but not exclusively, to electrodes used in the field of neural modulation.

[0004] background

[0005] Electrochemical performance of electrodes is one of the highest priority areas for optimizing leads and cuffs used in neuromodulation and other applications. In neuromodulation, high-performance electrodes enable safe and effective therapeutic delivery. Ensuring high electrode performance requires more than just material selection and development. Even when electrode materials and their charge injection capabilities are optimized for the target therapy, leads may still fail to achieve the desired electrochemical performance if the charge injection surface is blocked by contaminants or other non-conductive manufacturing residues. The presence of silicone flashes from lead manufacturing and assembly processes on the electrode's charge injection surface can severely impair electrochemical performance and vary with the lead, making system optimization tailored for therapeutic purposes challenging.

[0006] Known solutions to this problem have drawbacks. One solution is to use thin-film technology to integrate the electrode directly onto the substrate, completely bypassing the molding step. The disadvantage of this approach is that, for chronic implantation applications, the thin-film material is not soft enough and is not as well-tested as silicone. Furthermore, it exhibits limited manufacturing freedom for fine-tuning the three-dimensional shape factor of neural interface devices (such as cuff electrodes or paddle electrodes) to accommodate highly variable patient anatomy and patient baseline information.

[0007] Overview

[0008] The inventors' detailed failure analysis revealed that the electrodes could be partially covered by silicone overflow from the molding process. This silicone overflow covering the electrode surface reduces the effective surface area through which treatment can be delivered. The silicone overflow can be attributed to leakage of pressurized and heated silicone around the electrode edges during manufacturing.

[0009] This disclosure addresses the problems discussed and describes the electrode assembly and method of manufacturing the electrode assembly according to the present invention. According to one embodiment, the method of manufacturing the electrode assembly includes the steps of: assembling one or more electrodes into a first-shot molded silicone having a positioning aid window; tagging down the electrodes with an implant-grade adhesive; electrically connecting one or more electrodes to an intermediate conductive wire or coil via laser or resistance welding; applying adhesive backfill to one or more electrodes and the interconnect; and a second injection applying material to the adhesive backfill and the electrodes.

[0010] In one particular embodiment, the first injection, the second injection, and the adhesive backfill may all contain silicone, but the injections and the backfill may use different materials. Furthermore, the first injection may use blind pockets shaped to match the contours of the electrode or electrode plate to secure the electrode or electrode plate in its desired position. The second injection, molded during high-pressure molding, may be applied after the adhesive backfill has cured. The adhesive backfill material may be applied to seal any gaps between the metal electrode and the first injection, preventing silicone from the second injection molding from being introduced into cracks and reaching the electrode on the tissue-facing surface.

[0011] In one embodiment, a method for manufacturing an implantable electrode assembly for neural modulation is provided, comprising: forming a first material layer including a hole formed therein; placing an electrode in the hole in the first material layer; connecting an electrical lead to the electrode; applying a backfill material to the electrode, the electrical lead connection, and a portion of the first layer sufficient to seal any gaps between the electrode and the hole; and applying a second material layer to the backfill material.

[0012] In one embodiment, an electrode assembly is provided, comprising: a first material layer having a hole formed therein; an electrode configured to be disposed within the hole and connectable to a lead; a backfill material applied to the electrode and the lead, and to any exposed portion of the electrical connection between the electrode and the lead; and a second material layer applied to the backfill material and a portion of the first layer; and wherein the backfill material fills any opening between the electrode and the first layer, thereby sealing any leakage path between the electrode and the second layer, which may cover a portion of the exposed surface of the electrode.

[0013] In one embodiment, an electrode assembly for neural modulation is provided, comprising: a first material layer having an opening; an electrode at least partially provided in the opening for connection to a lead; a backfill provided on the electrode, the backfill covering the edge of the electrode and at least a portion of the electrical connection between the electrode and the lead; and a second material layer provided on the backfill and a portion of the first layer, wherein the backfill seals any opening between the electrode and the first layer to reduce leakage paths between the target contact surface of the electrode and the second layer.

[0014] The detailed features of this disclosure are described below. Brief description of the attached diagram

[0016] Figure 1A This is a cross-sectional view of an exemplary implantable device that is fitted around a nerve bundle.

[0017] Figure 1B These are plan views and cross-sectional views of an electrode assembly manufactured according to this disclosure.

[0018] Figure 2 These are plan views and cross-sectional views of the electrode assembly and conductive wires according to this disclosure.

[0019] Figure 3 This is a flowchart of a method for manufacturing an electrode assembly according to the present disclosure.

[0020] Detailed description of exemplary embodiments

[0021] This disclosure relates to systems and apparatus for stimulating nerves intravenously or extravenously using an implantable device comprising one or more electrodes positioned near the end of a lead or within a neural interface device (including a cuff or flat paddle lead), the implantable device being implanted within or around a blood vessel (e.g., an artery, vein, or nerve or nerve bundle) such that the electrodes are in contact with surface tissue. Neural stimulation can be defined as the delivery of electrical current (e.g., electrical impulses) to neurons, nerve cells, nerve bundles, or other target locations in the nervous system to excite neurons, nerve cells, nerve bundles, or other target locations.

[0022] Figure 1A An exemplary system is depicted, comprising an implantable device 10 formed of a flexible biocompatible material, such as a biocompatible thermoplastic elastomer, a soft polymer substrate, etc., which can be used to utilize a power source 12 (not otherwise shown). Figure 1A (In the middle) Electrical stimulation of nerves induced in implantable devices. Figure 1A The implantable device 10 shown is an extravascular device in the form of a cuff that wraps around a nerve or blood vessel (not shown). The implantable device 10 is provided as an example only and many different shapes, configurations, sizes, etc., can be enabled. For example, the implantable device does not need to completely wrap around the target; it can be paddle-shaped and used for both extravascular and intravascular applications, or other configurations for stimulating nerve tissue.

[0023] The implantable device 10 may include one or more electrodes 12, sensors, or arrays thereof, each array including one or more sets of electrodes or sensors. In some embodiments, each electrode 12 may be configured to emit an electric field to stimulate nerves adjacent to the implantable device 10. Each set of electrodes 12 within an electrode array may include one or more separate electrodes for this purpose.

[0024] Each electrode 12 (or a group of such electrodes, etc.) may be coupled to a conductive wire or coil lead 30 made of essentially a conductive material. Figure 2 ), such as micro-coil leads, to achieve high-density flexible interconnects (not shown). In some embodiments, for example, the conductive wires or coil leads 30 may substantially (e.g., 90 or 95% by weight) comprise metals such as platinum, stainless steel (e.g., MP35N or titanium). Other metals, such as gold, may also be used. Figure 1A As shown, electrode 12 can be connected in series and / or in parallel to other electrodes to provide multiple channels, thereby improving the selectivity of parameters of the emitted electric field (e.g., magnitude, direction, location, etc.). In some embodiments, this arrangement can provide more targeted and effective neural stimulation.

[0025] If necessary or required, electrodes 12 may be coupled via leads 30 to one or more other components (not shown) of the implantable device 10, such as the main lead body of the neural interface device, control circuitry, battery pack, capacitor memory, and / or other rechargeable storage elements. In one embodiment, each electrode 12 is connected (i.e., soldered or otherwise suitable) to the leads 30 and subsequently to flexible interconnect leads (not shown) of the neural interface device 10. The interconnect leads may be directly connected to the lead body or provide electrical connections between the leads 30, in series or in parallel as needed. The leads 30 may be microcoils or other suitable flexible leads. The interconnect leads may also (and / or alternatively) be directly connected to the lead body or provide electrical connections between the electrodes 12, in series or in parallel as needed. The interconnect leads may be microcoils or other suitable flexible leads. Thus, in some embodiments, leads 30 may consist of both leads 30 and interconnect leads. In other embodiments, leads 30 may consist only of interconnect leads. In other embodiments, lead 30 may include only interconnecting leads between electrodes 12 and include interconnecting leads as part of lead 30 that can be connected to lead body.

[0026] Electrode 12 may be a sensor or sensor array that measures physical or temporal parameters relating to the implantable device 10 and / or its surrounding environment. For example, in one embodiment, the sensor array may include a sensor for measuring the potential between two points. Furthermore, the sensor array may include other sensors for measuring other characteristics such as pressure, temperature, time, resistance, conductance, electrical flux / magnetic flux, etc. Each sensor in the sensor array may be coupled to any other component of the implantable device 10, such as control circuitry, electrode 12, power source, etc.

[0027] The components of the implantable device 10 may be formed within or attached to a flexible polymer substrate 14 such that the substrate supports the formed or attached components. In some embodiments, the substrate 14 may comprise a monolithic flexible polymer material, such as silicone, to facilitate implantation into and operation within a patient. In some embodiments, the substrate 14 may comprise multiple material layers with various components, such as electrodes 12 or arrays, sensors, and wires or coils 30, disposed between the layers. In one embodiment, the first layer may be formed in a mold, wherein heated silicone is injection molded under pressure, i.e., “injected” into the mold. A series of holes in the first injection layer may be formed or cut into the first layer (once the first layer has cured) by the mold. Once the holes have been formed, one or more electrodes may be disposed in the holes, wherein the electrodes are then connected to the wires or coils 30, typically by soldering leads to the back of the electrodes. Once the electrodes and leads are soldered, a second injection layer of heated and pressurized flexible polymer material may be disposed on the back of the electrodes to seal the electrodes between the first and second injection layers and hold them in place within their respective holes.

[0028] The following methods have been found to be consistently effective in preventing the aforementioned types of silicone spills. Figure 1B It is along Figure 1A The cross-section of line AA. For example... Figure 1B As shown, the first material layer 22 may be a first injection of silicone, polymer, or a biocompatible thermoplastic elastomer material or a biocompatible thermoplastic polyurethane. The first material layer 22 may be configured to include one or more holes 23, each of which can hold a metal electrode 24 in a desired location. The electrode 24 is placed in the hole 23 such that the front face of the electrode is substantially coplanar with the exposed surface of the first layer 22. A backfill material 26, such as a silicone adhesive, may then be applied to the back face of the electrode 24 without heat or pressure, or at least without pressure, thereby forming a seal on the electrode and a portion of the first layer, thereby closing any remaining openings between the electrode 24 and the first layer 22 around the edge of the hole 23. A second material layer 28, similar to the first layer, may then be applied over the backfill material 26.

[0029] The backfill material 26 may contain a material with a different hardness compared to the first layer 22 and the second layer 28. For example, the backfill material 26 may contain a material that is softer (or less rigid) than the first layer 22 and the second layer 28. In one example, the hardness of the first layer 22 and the second layer 28 may be approximately 50 Shores A–90 Shores A, advantageously 60–85 Shores A, advantageously 70–80 Shores A; and the hardness of the backfill material 26 may be ≥30 Shores A, advantageously ≥25 Shores A, advantageously ≥20 Shores A, advantageously ≥15 Shores, advantageously ≥10 Shores (e.g., measured using a Shore hardness tester).

[0030] In one embodiment, instead of using the same material for the first and second layers, the layers can be made of different materials. For example, the first layer can be made of a more rigid silicone or polymer material to make it more difficult for the metal electrode to tear through the first layer and to potentially cut into the neurovascular bundle (NVB) to which the neural interface device is applied. The second layer can then be a different material with different rigidity or the same material (silicone) with lower rigidity, configured to elicit a more favorable tissue response or to contribute to a more flexible shape factor of the neural interface device, which can benefit from reducing the pressure applied to the NVB and thereby reducing the risk of mechanically induced tissue damage. If two layers with different materials or rigidities are used, it is ideal to prevent uncontrolled mixing of the two layers, as changes in the mechanical modulus distribution can cause the neural interface device to deform in unpredictable ways due to the accumulation of residual stress. Improved control of these two layers can be achieved by using the manufacturing methods described in this disclosure.

[0031] It is possible to do as Figure 2 The electrode 24 is connected to the lead 30 as shown, after which backfill 26 is applied. Laser welding or other suitable techniques can be used to connect the lead 30 to the electrode 24 and provide an electrical connection between the electrode and the lead body (not shown) or the interconnecting leads as described above. For example, at least one of the following can be used for the electrical connection between the lead and the electrode: welding (laser or resistance), crimping, and conductive adhesive.

[0032] Applying backfill 26 to the lead connection of electrode 24 helps to further fix the lead connection over time. The second material layer 28 is applied only after the backfill 26 has cured.

[0033] refer to Figure 3 The method for manufacturing an electrode assembly according to this disclosure includes steps designated S1 to S6:

[0034] S132: Establish a first material layer for the neurostimulation device, such as by first injection filling a mold with a material such as silicone to form the first layer. The first layer may include a plurality of holes formed by the mold or a plurality of holes cut out from the first layer after molding.

[0035] S233: Place one or more electrodes in the holes of the first layer.

[0036] S334: Apply backfill material, such as silicone adhesive, along the electrode edge (where coil soldering will not be performed) to one or more electrodes in each hole to secure the electrodes in place for soldering. Backfill material may be applied in small amounts. Ensure proper curing of the backfill material by following the adhesive manufacturer's curing profile, which may be moisture-curing or UV-curing.

[0037] S435: Soldering or otherwise attaching leads or similar devices to the back of one or more electrodes or interconnection points to form a physical and electrical connection between the electrodes and leads.

[0038] S536: Apply backfill to the back of the electrode and the soldered interconnects or exposed leads, as well as a portion of the first layer, to form a complete seal between the electrode, leads, and holes, thereby preventing leakage paths between the back and front of the electrode. Ensure proper curing of the adhesive as shown in S3.

[0039] S637: The first backfill layer is placed in the mold and a second injection of silicone material is applied to the back of the electrode to complete the nerve stimulation device.

[0040] Other biocompatible materials can be used instead of silicone, such as other biocompatible polymers. Similarly, different biocompatible materials can be used as backfill materials compared to silicone-only adhesives.

[0041] Furthermore, those skilled in the art will understand that although the manufacturing steps described above have been presented as an example, some of the order of the manufacturing steps can be changed. For example, the order of steps S233 to S536 can be changed so that the step of connecting the electrical leads to the electrodes (e.g., S435) is performed before applying backfill material (e.g., S334), before placing the electrodes in the holes (electrode positioning windows) in the first layer (e.g., S233), or even before forming the first layer (e.g., S132). In other words, a pre-connected (e.g., soldered) electrode and lead sub-assembly can be provided before placing the electrodes in the holes in the first layer, before applying backfill material, or even before forming the first layer.

[0042] In addition to or as an alternative to the foregoing, the following examples consistent with this teaching are listed in the following numbered clauses:

[0043] 1. A method for manufacturing an implantable electrode assembly (20) for neural modulation, comprising:

[0044] A first material layer (22) is formed, which includes pores (23) formed therein;

[0045] The electrode (24) is placed in a hole in the first material layer;

[0046] Connect the electrical lead (30) to the electrode;

[0047] Apply backfill material (26) sufficient to seal any gaps between the electrode and the hole to the electrode, lead connection, and a portion of the first layer; and

[0048] Apply a second material layer (28) over the backfill material.

[0049] 2. The method of Clause 1, wherein one or more of the first material layer and the second material layer are formed by a first injection and a second injection of a heated and pressurized polymer material.

[0050] 3. The method of Clause 2, wherein the material of the first layer formed by the first injection or the second layer formed by the second injection comprises silicone.

[0051] 4. The method of Clause 2, wherein one or more of the first material layer and the second material layer comprises a biocompatible thermoplastic elastomer.

[0052] 5. The method of Clause 1, wherein the backfill material comprises an adhesive silicone.

[0053] 6. The method of Clause 1, wherein the combination of a first material layer and holes fixes each electrode in the desired position.

[0054] 7. The method of Clause 6, further comprising, prior to connection, applying a second backfill material between the electrode edge and the hole to secure the electrode in place for connection.

[0055] 8. The method of Clause 7, wherein the second backfill material comprises an adhesive silicone.

[0056] 9. The method of Clause 7, further comprising curing a second backfill material prior to the application of the backfill material.

[0057] 10. The method of Clause 1, further comprising curing the backfill material prior to applying the second material layer.

[0058] 11. The method of Clause 1, wherein applying the second material layer includes high-pressure injection molding.

[0059] 12. The method of Clause 1, wherein the backfill material seals any leakage path between the electrode and the second material layer, and wherein the second material layer is one of a heated and pressurized polymer material and a heated and pressurized flexible thermoplastic elastomer.

[0060] 13. The method of Clause 1, wherein the first material layer is different from the second material layer.

[0061] 14. The method of Clause 1, wherein the first material layer has a first hardness and the second material layer has a second hardness, and wherein the first hardness and the second hardness are different.

[0062] 15. The method of Clause 1, wherein connecting an electrical lead to an electrode comprises connecting one end of a flexible lead to an electrode and connecting the opposite end of the flexible lead to a lead body.

[0063] 16. The method of Clause 15, wherein the flexible lead is a micro coil.

[0064] 17. The method of Clause 1, wherein connecting an electrical lead to an electrode comprises connecting one end of an interconnecting lead to an electrode and connecting the opposite end of the interconnecting lead to a lead body.

[0065] 18. The method of Clause 1, wherein connecting an electrical lead to an electrode comprises connecting one end of a flexible lead to an electrode and connecting the opposite end of the flexible lead to an interconnecting lead.

[0066] 19. The method of Clause 18, wherein an interconnecting lead is connected to a second flexible lead connected to a second electrode.

[0067] 20. The method of Clause 18, wherein interconnecting leads are connected to lead bodies.

[0068] 21. An electrode assembly, comprising:

[0069] A first material layer having pores formed therein;

[0070] The electrode is configured to be placed inside the hole;

[0071] Leads soldered to the electrodes;

[0072] Adhesive refill applied to electrodes, leads, and any exposed portions of solder joints; and

[0073] A second material layer is applied to the adhesive refill and a portion of the first layer;

[0074] The first layer is configured to fix the electrodes in the desired positions;

[0075] The second layer includes the application of high pressure; and

[0076] The adhesive backfill fills any openings between the electrode and the first layer, thereby sealing any leakage paths between the electrode and the second layer, which may cover a portion of the exposed surface of the electrode.

[0077] 22. The electrode assembly of Clause 21, wherein the first material layer, the backfill, and the second material layer are one or more of silicone, polymer, and biocompatible thermoplastic elastomer.

[0078] 23. The electrode assembly of Clause 22, wherein the first material layer and the second material layer are identical.

[0079] 24. The electrode assembly of Clause 22, wherein the first material layer and the second material layer are different.

[0080] 25. The electrode assembly of Clause 24, wherein a first material layer has a first hardness and a second material layer has a second hardness, and wherein the first hardness and the second hardness are different.

[0081] 26. The electrode assembly of Clause 21 further includes a second adhesive backfill material applied to the electrode edges and holes prior to the application of welding to position the electrode in the desired location.

[0082] 27. The electrode assembly of Clause 26, wherein the adhesive backfill is applied after the second adhesive backfill material has cured.

[0083] 28. The electrode assembly of Clause 21, wherein a second layer is applied after the backfill has cured.

[0084] 29. The method of Clause 21, wherein the lead wire soldered to the electrode is a flexible lead wire having one end soldered to the electrode and the opposite end of the flexible lead wire connected to the lead wire body.

[0085] 30. The method of Clause 29, wherein the flexible lead is a micro coil.

[0086] 31. The method of Clause 21, wherein the lead wire soldered to the electrode is an interconnecting lead wire having one end soldered to the electrode and the opposite end connected to the lead wire body.

[0087] 32. The method of Clause 21, wherein the lead soldered to the electrode is a flexible lead having one end soldered to the electrode and the opposite end connected to an interconnect lead.

[0088] 33. The method of Clause 32, wherein an interconnecting lead is connected to a second flexible lead, the second flexible lead being soldered to a second electrode.

[0089] 34. The method of Clause 32, wherein interconnecting leads are connected to lead bodies.

[0090] 35. A method for manufacturing an implantable electrode assembly (20) for neural modulation, comprising:

[0091] Connect the electrical lead (30) to the electrode;

[0092] A first material layer (22) is formed, which includes pores (23) formed therein;

[0093] The electrode (24) is placed in a hole in the first material layer;

[0094] Apply backfill material (26) sufficient to seal any gaps between the electrode and the hole to the electrode, lead connection, and a portion of the first layer; and

[0095] Apply a second material layer (28) over the backfill material.

[0096] 36. A method for manufacturing an implantable electrode assembly (20) for neural modulation, comprising:

[0097] A first material layer (22) is formed, which includes pores (23) formed therein;

[0098] Connect the electrical lead (30) to the electrode;

[0099] The electrode (24) is placed in a hole in the first material layer;

[0100] Apply backfill material (26) sufficient to seal any gaps between the electrode and the hole to the electrode, lead connection, and a portion of the first layer; and

[0101] Apply a second material layer (28) over the backfill material.

[0102] The foregoing description of examples of the invention (including illustrated examples) is given for illustrative purposes only and is not intended to be exhaustive or to limit the invention to the exact forms disclosed. Many modifications, adjustments, and uses will be apparent to those skilled in the art without departing from the scope of the invention. The illustrative examples described above are given to introduce the general subject matter discussed herein and are not intended to limit the scope of the concepts disclosed.

Claims

1. A method for manufacturing an implantable electrode assembly (20) for neural modulation, comprising: A first material layer (22) is formed, which includes pores (23) formed therein; The electrode (24) is placed in a hole in the first material layer; Connect the electrical lead (30) to the electrode; Apply backfill material (26) sufficient to seal any gaps between the electrode and the hole to the electrode, electrical lead connection and part of the first layer; and A second material layer (28) is applied to the backfill material. The backfill material contains an adhesive silicone, and / or the backfill material fills any leakage path between the electrode and a second material layer that may cover a portion of the exposed surface of the electrode.

2. The method of claim 1, wherein one or more of the first material layer and the second material layer are formed by a first injection and a second injection of a heated and pressurized polymer material.

3. The method of claim 2, wherein the material of the first layer formed by the first injection or the second layer formed by the second injection comprises silicone.

4. The method according to claim 1 or 2, wherein one or more of the first material layer and the second material layer comprises a biocompatible thermoplastic elastomer.

5. The method of claim 1, wherein the combination of the first material layer and the holes fixes the electrodes in the desired positions.

6. The method of claim 5, further comprising, prior to connection, applying a second backfill material between the electrode edge and the hole to secure the electrode in place for connection.

7. The method of claim 6, wherein the second backfill material comprises an adhesive silicone.

8. The method according to claim 6 or 7, further comprising curing the second backfill material before applying the backfill material.

9. The method of claim 1, further comprising curing the backfill material prior to applying the second material layer.

10. The method of claim 1, wherein applying the second material layer comprises high-pressure injection molding.

11. The method of claim 1, wherein the second material layer is one of a heated and pressurized polymer material and a heated and pressurized flexible thermoplastic elastomer.

12. The method of claim 1, wherein the first material layer is different from the second material layer.

13. The method of claim 1, wherein the first material layer has a first hardness and the second material layer has a second hardness, and wherein the first hardness and the second hardness are different.

14. The method of claim 1, wherein connecting the electrical lead to the electrode comprises connecting one end of the flexible lead to the electrode and connecting the opposite end of the flexible lead to the lead body.

15. The method of claim 14, wherein the flexible lead is a microcoil.

16. The method of claim 1, wherein connecting the electrical lead to the electrode comprises connecting one end of the interconnecting lead to the electrode and connecting the opposite end of the interconnecting lead to the lead body.

17. The method of claim 1, wherein connecting the electrical lead to the electrode comprises connecting one end of the flexible lead to the electrode and connecting the opposite end of the flexible lead to the interconnect lead.

18. The method of claim 17, wherein the interconnecting lead is connected to a second flexible lead connected to the second electrode.

19. The method of claim 17 or 18, wherein the interconnecting leads are connected to the lead body.

20. The method of claim 1, wherein the step of connecting the electrical leads to the electrodes may be performed before the step of forming the first material layer or before the step of placing the electrodes in a hole in the first material layer, the first material layer including the hole formed therein.

21. The method of claim 1, wherein the first layer is more rigid than the second layer.

22. The method of claim 1, wherein the backfill material is softer than the first layer and the second layer.

23. An electrode assembly for neural modulation, comprising: A first material layer having pores formed therein; An electrode configured to be placed inside a hole and connected to a lead; Backfill material applied to electrodes and leads, as well as any exposed portions of the electrical connection between electrodes and leads; and A second material layer is applied to the backfill and a portion of the first layer; and The backfill filler fills any openings between the electrode and the first layer, thereby sealing any leakage path between the electrode and the second layer, which may cover a portion of the exposed surface of the electrode.

24. An electrode assembly for neural modulation, comprising: The first material layer includes the opening; At least partially, an electrode that can be connected to a lead is provided in the opening; Backfill material provided on the electrode, the backfill material covering the edge of the electrode and at least a portion of the electrical connection between the electrode and the lead; and A second material layer is provided on the backfill and a portion of the first layer, wherein the backfill seals any gaps between the electrode and the first layer to reduce the leakage path between the target contact surface of the electrode and the second layer.

25. The electrode assembly according to claim 23 or claim 24, wherein the opening is adapted to accommodate an electrode.

26. The electrode assembly according to claim 23 or claim 24, wherein the electrode is connected to the lead by at least one of the following: soldering, crimping, and conductive adhesive.

27. The electrode assembly according to claim 23 or claim 24, wherein the electrical connection is at least one of the following: welding, crimping, or conductive adhesive.

28. The electrode assembly of claim 23 or claim 24, wherein the backfill comprises an adhesive silicone.

29. The electrode assembly according to claim 23 or claim 24, wherein the second layer includes high voltage application.

30. The electrode assembly of claim 23 or claim 24, wherein the first layer is configured to fix the electrode in the desired position.

31. The electrode assembly according to claim 23 or claim 24, wherein the backfill material covers the outer peripheral edge of the electrode.

32. The electrode assembly according to claim 23 or claim 24, wherein the first material layer, the backfill, and the second material layer are one or more of silicone, polymer, and biocompatible thermoplastic elastomer.

33. The electrode assembly according to claim 32, wherein the first material layer and the second material layer are identical.

34. The electrode assembly according to claim 32, wherein the first material layer and the second material layer are different.

35. The electrode assembly of claim 34, wherein the first material layer has a first hardness and the second material layer has a second hardness, and wherein the first hardness and the second hardness are different.

36. The electrode assembly of claim 23 or claim 24, further comprising a second backfill material containing an adhesive applied to the electrode edges and holes prior to electrical connection to position the electrodes in the desired locations, wherein optionally the electrical connection comprises performing welding.

37. The electrode assembly of claim 36, wherein the backfill material comprises an adhesive and is applied after the second backfill material has cured.

38. The electrode assembly according to claim 23 or 24, wherein a second layer is applied after the backfill has cured.

39. The electrode assembly according to claim 23 or 24, wherein the lead connected to the electrode is a flexible lead having one end soldered to the electrode and the opposite end of the flexible lead connected to the lead body.

40. The electrode assembly of claim 39, wherein the flexible lead is a microcoil.

41. The electrode assembly according to claim 23 or 24, wherein the leads connected to the electrodes are interconnecting leads having one end soldered to the electrode and the opposite end connected to the lead body.

42. The electrode assembly according to claim 23 or 24, wherein the lead connected to the electrode is a flexible lead having one end connected to the electrode and the opposite end connected to an interconnect lead.

43. The electrode assembly of claim 42, wherein the interconnecting lead is connected to a second flexible lead connected to the second electrode.

44. The electrode assembly according to claim 42 or 43, wherein interconnecting leads are connected to the lead body.

45. The electrode assembly according to claim 23 or 24, wherein the first layer is more rigid than the second layer.

46. ​​The electrode assembly according to claim 23 or 24, wherein the backfill material is softer than the first layer and the second layer.

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