An electrode implantation tool

Abstract

This invention discloses an electrode implantation tool. The distal end of the electrode is provided with a fixing component. The implantation tool includes an outer sheath and an inner sheath. The inner sheath includes an inner sheath tube and a first handle. The outer sheath includes an outer sheath tube and a second handle. The inner sheath tube can be inserted into the outer sheath tube. The first handle can be locked within the second handle. The second handle has at least a first locking position and a second locking position in the axial direction, allowing the first handle to move from the first locking position to the second locking position. The inner diameter of the inner sheath tube is smaller than the outer diameter of the fixing component, and the inner diameter of the outer sheath tube is larger than the outer diameter of the fixing component. Other parts of the electrode, excluding the fixing component, can be inserted into the inner sheath tube. This invention allows for a single puncture of the electrode and implantation tool near the target nerve tissue. After successful testing, the electrode is directly released and fixed, ensuring consistency between the test point and the implantation point.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to an electrode implantation tool. Background Technology

[0002] It is now understood that many diseases can be treated by electrical stimulation of nerves. For example, acute and chronic pain can be treated with electrical stimulation for a long time. Pain nerve electrical stimulation systems include implantable spinal nerve stimulators, non-implantable epidermal stimulation, and peripheral nerve treatment using percutaneous implantable electrodes and external electrical stimulators. Sacral nerve stimulation can treat patients with urinary and fecal incontinence. Parkinson's patients can have their muscle rigidity treated and mobility restored through electrode stimulation of the thalamus. Although these devices alleviate pain and improve quality of life for patients, these stimulation systems have various defects and limitations. Furthermore, due to differences in patient anatomy, insufficient electrical stimulation energy can result from unreliable electrode fixation mechanisms that fail, or from the fixation mechanism not fully integrating with muscle tissue, causing electrode displacement. Another more important reason is problems with the implantation tool itself, making it impossible to guarantee that the surgeon can implant and fix the electrode in the intended position. Doctors need to rely on experience, skill, and luck to achieve the precise implantation point.

[0003] Current electrode implantation tools were developed from those used for spinal pain stimulation electrodes and have been applied in percutaneous nerve stimulation. Chinese doctors also frequently use spinal implantation electrodes in the treatment of percutaneous peripheral pain. Because this is off-label use, neither the electrodes nor the implantation tools fully meet the requirements for peripheral percutaneous implantation. The implantation tools are typically 14G puncture needles with a relatively large outer diameter.

[0004] The advantage of these implantation tools is that they have been used globally, especially in the United States, for over 20 years in spinal and nerve stimulation therapy, demonstrating good safety. However, their effectiveness in currently developing percutaneous peripheral nerve stimulation therapy is relatively poor because the diameter of percutaneous stimulation electrodes (0.5-1.0 mm) needs to be smaller than that of spinal stimulation electrodes (around 1.3 mm) to minimize percutaneous trauma and reduce the risk of infection. Thus, the small diameter of percutaneous electrodes is inextricably linked to the implantation tools used to deliver them, and this requirement has become one of the pain points in the industry.

[0005] Patent CN108472484A discloses an implantable electrode in which the axial movement of the outer and inner sheaths during delivery allows the distal electrode to be locally exposed near the nerves in the human tissue. The stimulator forms a circuit by connecting one end of the outer sheath and the other end of the inner sheath to conduct electrical information, thereby stimulating the tissue at that point and evaluating whether the expected effect has been achieved. If the expected effect cannot be achieved, the inner and outer sheaths are moved axially to evaluate the next nerve stimulation point. The problem with this patent is that (1) the distal end of the electrode is designed to be delivered only a very small part by the delivery sheath. If the proximal end of the distal hook is also delivered out of the bottom of the blade tip of the outer sheath, the tip electrode will be released into the tissue. Once released, it cannot be retracted, and the electrode can only stay at that point. If the electrical properties at that point cannot meet the requirements for stimulation therapy, the implanted electrode needs to be replaced with a new electrode, resulting in waste. It is quite difficult to control the movement of the inner sheath within the outer sheath in this way, which is extremely difficult to achieve in actual products; (2) In claim 3 of this patent, the opening at the proximal end of the inner sheath opening is used to place the distal hook electrode inside. The result may be that the distal electrode hook part gets stuck in the opening and cannot be released. Moreover, the original purpose of this design was to reduce the diameter of the implantation tool, but since the wall thickness of the inner sheath at the distal end of the opening still exists, the actual diameter of the total electrode and inner sheath assembly cannot be reduced, nor can the inner diameter of the inner sheath assembly that the outer sheath needs to accommodate to deliver the electrode be reduced. Therefore, the intention of the opening cannot be achieved. (3) Similarly, the axial slot it sets cannot achieve the effect of reducing the diameter of the outer sheath. (4) The patent also discloses that a guide wire (stylet) can be embedded in the center of the electrode inner sheath delivery assembly. According to the detailed description of the patent, the inner sheath size (165 segments) has an outer diameter of 0.7-1.0 mm and an inner diameter of 0.5-0.9 mm. The example is an inner diameter of 0.61 mm. Currently, the guide wire of cardiac pacemaker is about 0.35 mm. Because any smaller diameter would not be rigid enough, and the 0.61 mm inner diameter here would be occupied by the diameter of the electrode, it can be said that the guide wire in this patent is unlikely to have a practical role in pushing the electrode. (5) Since the implantation tool of the peripheral nerve electrode directly affects the patient's puncture trauma, the design of the peripheral nerve electrode must not only consider the small diameter of the electrode, but also the small diameter of the implantation tool. This is to effectively reduce the risk of infection and reduce patient trauma. The smallest peripheral implantation tool on the market is 17G (1.47 mm). If the patient has little muscle and fat and is thin, a thinner implantation tool is more suitable. In summary, percutaneous peripheral electrode implantation is a relatively new field both domestically and internationally. Existing technologies still have many shortcomings and deficiencies, and there is room for optimization.

[0006] Existing implantable electrodes utilize a distal helical structure. For example, patent US2005251240A1 describes the design principle of this distal helical structure for intracardiac fixation. The main principle is that, based on the need for endocardial fixation, the helix of the pacemaker electrode must not be exposed during implantation; it is hidden within the distal cannula. Once the distal electrode is delivered to the intended position on the endocardium, a connecting pin at the proximal end (connected to the helical wire of the electrode body) rotates the electrode (or the entire electrode rotates), releasing the distal helix hook onto the endocardium. This works like a screw drilling into wood, fixing the pacemaker electrode to the myocardium. The connecting pin then functions as an implantation tool to release the distal fixation mechanism. However, this invention and principle are based on a pacemaker electrode diameter of 7F-8F (2.33mm-2.66mm). Within this size, a helical structure and a proximal connecting pin can be accommodated radially within the electrode, along with an implantation tool and a guide wire. The guide wire provides support, allowing the proximal rotation to drive the distal release and fixation. The natural conditions of this size and space do not exist in the percutaneous implantation electrode environment. Therefore, the design structure of the distal end of the percutaneous implantation electrode must be combined with the design of the implantation tool structure to achieve the fixation of the distal end of the implantation electrode on the human tissue and muscle.

[0007] Patent CN108136175A discloses an epicardial defibrillation lead with a side-spiral fixation device and its placement, and specifically discloses (see paragraphs

[0064] -

[0073] of the specification): the fixation mechanism 30 may be located at the distal end of the lead 18 to attach the lead 18 to the epicardial tissue; the side-spiral member 30 is configured such that it extends radially outward from the electrode lead a short distance and then spirally coils around at least a portion of the longitudinal axis along the circumference of the lead body (equivalent to the fixation member being a spiral structure); the position of the spiral fixation member 30 is based on the specific application and the intended cardiac anatomy, and for small anatomy such as pediatric patients, the spiral position may be in the range of about 3 cm to about 6 cm from the distal tip to allow the positioning of a defibrillation electrode about 2 cm to about 5 cm long; the side-spiral member 30 includes a main outer diameter (OD) approximately equal to to 1.5 F (French) (=0.5 mm) larger than the outer diameter of the lead body (equivalent to the outer diameter of the fixation member being larger than the outer diameter of the electrode body). Although the structure of this patent is somewhat similar and also serves as an electrode fixation function, its working mechanism is different from that of percutaneous electrode delivery and fixation. This is because (1) this is a cardiac rhythm electrode, which can be as large and rigid as 2.33mm-2.66mm in diameter, making it easy to push and operate for fixation. Secondly, it can accommodate the guide wire, which provides support and rotation during implantation. (2) The mechanism by which its spiral structure is larger than the electrode body is to rotate the electrode under the support of the guide wire and its own rigidity. The side spiral component is 1.5F larger than the defibrillation electrode body, which is equivalent to attaching a screw to the tissue of the nearby blood vessel wall for fixation. This is completely different from the working mechanism of percutaneous electrode fixation and delivery, which cannot be pushed and rotated in an environment where there is no guide wire support and the electrode is extremely small and lacks rigid operating force.

[0008] Existing percutaneous electrical stimulation (PES) techniques require puncture testing with special test needles, which limits the direct testing and implantation of distal fixation mechanisms using implanted electrodes. There are two delivery and testing methods, each with its own steps and limitations:

[0009] 1) The implantation tool test needle is punctured together with the implantation tool to the expected implantation point for testing, and the outer sheath serves as a channel to retain the test needle. If the test is unsuccessful, the puncture is repeated; if the test is successful, the test needle is removed and the electrode is implanted again. The drawbacks of this approach are (1) an extra step; (2) an extra test needle.

[0010] 2) The implantation tool test needle is first punctured to the expected implantation point for testing. If the test is unsuccessful, the needle is punctured again for testing. If the test is successful, the test needle is removed and the implantation electrode delivery tool is inserted again. The defects of this scheme are (1) the test point and the re-implanted electrode do not completely coincide, which reduces the treatment effect; (2) one more puncture; (3) one more test needle.

[0011] Therefore, it is necessary to provide an electrode implantation tool that, through the cooperation of the implantation tool and components, allows the electrode and implantation tool to be punctured near the target human tissue nerve in one go. After successful testing, the electrode can be directly released and fixed, thus ensuring that the test point is the electrode implantation point and that the test point and implantation point are consistent. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide an electrode implantation tool that can insert the electrode and the implantation tool into the vicinity of the intended human tissue nerve in one puncture without the need for puncture testing with a test needle.

[0013] To address the aforementioned technical problems, the present invention provides an electrode implantation tool. A fixing component is provided at the distal end of the electrode. The implantation tool includes an outer sheath and an inner sheath. The inner sheath includes an inner sheath tube and a first handle. The outer sheath includes an outer sheath tube and a second handle. The inner sheath tube can be inserted into the outer sheath tube. The first handle can be locked within the second handle. The second handle has at least a first locking position and a second locking position in the axial direction, allowing the first handle to be moved from the first locking position to the second locking position. The inner diameter of the inner sheath tube is smaller than the outer diameter of the fixing component, and the inner diameter of the outer sheath tube is larger than the outer diameter of the fixing component. Other parts of the electrode, excluding the fixing component, can be inserted into the inner sheath tube.

[0014] Preferably, the inner diameter of the inner sheath is 0.5mm-0.7mm, and the outer diameter of the outer sheath is 1.07mm-1.27mm.

[0015] Preferably, the fixing component is a spiral structure, the inner diameter of the inner sheath is smaller than the outer diameter of the spiral structure, and the inner diameter of the outer sheath is larger than the outer diameter of the spiral structure.

[0016] Preferably, the distal end of the outer sheath has a first cutting edge.

[0017] Preferably, the first cutting edge has a first cutting edge and a second cutting edge in the axial direction from the distal end to the proximal end, the first cutting edge and the second cutting edge form an angle, the second cutting edge is a beveled plane, and the first cutting edge is a beveled arc surface.

[0018] Preferably, the second handle has two symmetrical locking grooves. Each locking groove includes an axially extending slide groove and a first limiting groove and a second limiting groove extending circumferentially. Both the first limiting groove and the second limiting groove communicate with the slide groove. The first limiting groove is located at a first locking position, and the second limiting groove is located at a second locking position. The first handle is provided with a locking member that matches the locking groove. The locking member includes a locking shaft and locking buckles located at both ends of the locking shaft. The locking shaft is inserted into the locking groove, and the size of the locking buckles is larger than the width of the locking groove.

[0019] Preferably, each locking groove further includes a third limiting groove opened along the circumferential direction, the third limiting groove communicating with the sliding groove, and the position of the third limiting groove being a third locking position for locking the first handle onto the second handle.

[0020] Preferably, when the outer sheath and the inner sheath are locked in the first locking position, the axial length of the outer sheath is 1-5 mm longer than the axial length of the inner sheath combined with the distal end of the electrode, and the axial distance between the first limiting groove and the second limiting groove is 10 mm-15 mm.

[0021] Preferably, the distal end of the inner sheath has a second blade, or the distal end of the inner sheath is flat-headed, and the distal edge of the inner sheath is chamfered circumferentially.

[0022] Preferably, the outer surface of the outer sheath is provided with a first mark, and the outer surface of the inner sheath exposed to the outer sheath in the test state is provided with a second mark.

[0023] Preferably, two radially extending push plates are symmetrically arranged on the proximal end of the second handle.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. The implantation point of existing electrical stimulation therapy often requires multiple searches and tests to be successful. How to keep the successfully tested point consistent with the final implantation point is a difficult problem in the design of the distal electrode and the implantation tool. The present invention, through the cooperation of the inner sheath and the distal electrode structure, and the cooperation of the inner sheath assembly and the outer sheath, allows the surgeon to puncture into the vicinity of the expected nerve and release the distal electrode a certain distance for testing. If the result is not ideal, the surgeon can withdraw the released distance, remove the outer sheath and the inner sheath assembly of the electrode, and re-puncture at a new position. After the test is successful, the distal electrode is completely released to integrate and fix it with human tissue. Therefore, it ensures that the implantation point of the distal electrode is consistent with the test point, thus solving this difficult problem. 2. The electrode implantation tool provided by this invention uses inner and outer sheaths that match the distal fixation mechanism of the implanted electrode. The implanted electrode works together with the implantation tool. During the delivery process, it cooperates with the distal fixation component to deliver and fix the distal electrode in the expected position, solving the technical difficulty of permanently fixing the implanted electrode in human tissue. 3. This invention uses the force cooperation between the outer sheath, the inner sheath for delivering the electrode, and the distal fixation structure of the electrode to deliver the electrode into the body and firmly integrate and fix it with human tissue, solving the problem of delivering and fixing the implanted electrode without a guide wire. 4. Percutaneous implantation of electrodes not only requires the electrode itself to have a small diameter, but the diameter of the implantation tool should also be as small as possible, because a large diameter results in greater trauma. Doctors and patients both hope for minimal trauma and no infection. The diameter of the percutaneous implantation tool should be as small as 17G-19G (1.07mm-1.47mm), which is another challenge in this technical field. The implantation tool provided by this invention can be 18G (1.27mm diameter), or even smaller (19G, 1.07mm) based on the radial dimensions of the electrode design, which is much smaller than the 14G (2.11mm diameter) implantation tool for spinal stimulation electrodes. Attached Figure Description

[0025] Figure 1a This is a schematic diagram of the implantation tool equipped with electrodes in the implantation state according to an embodiment of the present invention. Figure 1b for Figure 1a A partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes;

[0026] Figure 2a This is a schematic diagram of the implantation tool equipped with electrodes in a first test state according to an embodiment of the present invention. Figure 2b for Figure 2a A partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes;

[0027] Figure 3a This is a schematic diagram of the implantation tool equipped with electrodes in the second test state / retrieval and removal state according to an embodiment of the present invention. Figure 3b for Figure 3aA partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes;

[0028] Figure 4 This is a schematic diagram of the overall structure of the outer sheath in an embodiment of the present invention;

[0029] Figure 5 (a) Figure 5 (b) Figure 5 (c) is a partially enlarged schematic diagram of the distal end of the outer sheath in an embodiment of the present invention;

[0030] Figure 6a This is a schematic diagram of the structure of the inner sheath containing electrodes in an embodiment of the present invention. Figure 6b and Figure 6c This is a partially enlarged side view showing the engagement of two different structures of the second cutting edge at the distal end of the inner sheath and the spiral fixing component at the distal end of the electrode. Figure 6d and Figure 6e A magnified side view of the distal helical fixing component of the electrode at different bend angles;

[0031] Figure 7 This is a schematic diagram of the overall structure of the inner sheath in an embodiment of the present invention;

[0032] Figure 8 (a)- Figure 8 (d) is a side view of five different blade structures at the distal end of the inner sheath in the first embodiment of the present invention;

[0033] Figure 9 This is a front view of the second cutting edge at the distal end of the inner sheath in the second embodiment of the present invention;

[0034] Figure 10a , Figure 10b This is a schematic diagram of the parameter variables of the blade in an embodiment of the present invention;

[0035] Figure 11 (a)- Figure 11 (e) is a schematic diagram of the design parameters of five different cutting edges in an embodiment of the present invention;

[0036] Figure 12a This is a schematic diagram of the test connection in the first test method, showing the electrode connected to the stimulator via an adapter; Figure 12b This is a schematic diagram of the test connection of the inner sheath to the stimulator in the second test method.

[0037] In the picture:

[0038] 100-Implantation tool, 1-Outer sheath, 2-Inner sheath, 3-Blade, 4-Adapter, 5-Stimulator, 6-Electrode, 10-Fixing component, 11-Outer sheath tube, 12-Second handle, 13-Push plate, 14-Locking groove, 15-First blade, 16-First mark, 21-Inner sheath tube, 22-First handle, 23-Lock, 24-Locking shaft, 25-Second blade, 26-Second mark, 27-Cable, 31-First cutting edge, 32-Second cutting edge, 61-Electrode wire, 141-Slide groove, 142-First limiting groove, 143-Second limiting groove. Detailed Implementation

[0039] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0040] To more clearly describe the structural features of the present invention, the terms "proximal end," "distal end," and "axial" are used as directional terms, where "proximal end" refers to the end closer to the operator; "distal end" refers to the end farther from the operator; and "axial" refers to the direction in which the central axis of the inner or outer sheath lies or is parallel to the central axis of the inner or outer sheath. The term "or" is generally used in a meaning including "and / or" unless otherwise expressly indicated.

[0041] This invention provides an electrode implantation tool for delivering fully implantable peripheral electrodes or percutaneously implantable electrodes. In this embodiment, the "electrode" primarily refers to fully implantable peripheral electrodes or percutaneously implantable electrodes for use in peripheral nerve stimulation systems. This invention utilizes a combined design of an outer and inner sheath, along with the electrode and a special fixation structure at the distal end of the electrode (see patent application number CN202111154697.4 for details), to deliver a small electrode (0.6-0.7 mm in diameter) to the operator's intended implantation point without the support of a guide wire. Furthermore, it ensures the distal electrode is firmly fixed to the human tissue, reducing or even completely eliminating the clinical adverse event of electrode dislocation. Additionally, percutaneous electrical stimulation therapy often requires multiple attempts to locate the stimulation point to achieve pain suppression. After successful testing, the electrode is implanted near the test point. If the test point and implantation point are not punctured in a single session, it is difficult or impossible to keep the tested point consistent. This invention, through the design and component coordination of the implantation tool, enables the electrode and implantation tool to be inserted into the vicinity of the target human tissue nerve in a single puncture. After successful testing, the electrode is directly released and fixed, thus ensuring that the test point is the electrode implantation point and maximizing the consistency between the test point and the implantation point. Furthermore, it allows for firm fixation of the distal electrode to the tissue, reducing or even completely eliminating the clinical adverse event of electrode dislocation.

[0042] Figure 1a This is a schematic diagram of an implantation tool equipped with electrodes in the implantation state. Figure 1b for Figure 1aA partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes; Figure 6a This is a schematic diagram of the inner sheath containing electrodes.

[0043] Please see Figure 1a , Figure 1b and Figure 6a The electrode implantation tool provided by this invention has a fixing component 10 at the distal end of the electrode 6. The implantation tool 100 includes an outer sheath 1 and an inner sheath 2. The inner sheath 2 includes an inner sheath tube 21 and a first handle 22. The outer sheath 1 includes an outer sheath tube 11 and a second handle 12. The inner sheath tube 21 can be inserted into the outer sheath tube 11. The first handle 22 can be locked into the second handle 12. The second handle 12 has at least a first locking position and a second locking position in the axial direction that can lock the first handle 22. The inner diameter of the inner sheath tube 21 is slightly smaller than the outer diameter of the fixing component 10, and the inner diameter of the outer sheath tube 11 is slightly larger than the outer diameter of the fixing component 10. This allows the fixing component 10 to remain at the opening of the second blade 25 of the inner sheath tube 21 after the electrode 6 is inserted into the inner sheath tube 21, and at the same time, it can be combined with the inner sheath tube 21 and then inserted into the patient's body through the outer sheath tube 11. Further, the fixing component 10 has a spiral structure, such as... Figure 1b As shown, at this time, the inner diameter of the inner sheath tube 21 is smaller than the outer diameter of the spiral structure, and the inner diameter of the outer sheath tube 11 is larger than the outer diameter of the spiral structure. Other parts of the electrode 6, except for the fixing component 10, can be inserted into the inner sheath tube 21.

[0044] Please continue reading Figure 1a The inner sheath 2 is inserted into the outer sheath 1 for assembly, and the first handle 22 is locked onto the second handle 12 in the first locking position. In this state, the axial length of the outer sheath 11 is 1-5 mm longer than the axial length of the electrode 6 and the inner sheath 21 combined, so that the distal end of the inner sheath 21 and the fixing component 10 at the distal end of the electrode are both located inside the outer sheath 11. In this way, when the outer sheath 11 punctures human tissue, it protects the electrode 6 and the spiral fixing component 10 at the distal end of the inner sheath 21.

[0045] Figure 2a This is a schematic diagram of the implantation tool equipped with electrodes in the first test state. Figure 2b for Figure 2a A partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes; Figure 12a This is a schematic diagram of the test connection of the adapter connected to the electrodes in an embodiment of the present invention.

[0046] Please see Figure 2a , Figure 2b and Figure 12aAfter the operator inserts the puncture needle into place, the stimulator 5 is connected to the electrode 6 via the adapter 4 and the electrode wire 61 for testing. In the first testing method, after the first handle 22 is unlocked from the first locking position, the outer sheath 1 is moved axially towards the proximal end until the part of the inner sheath tube 21 exposed at the distal end of the electrode 6 is exposed to form a test electrode. The test electrode, the stimulator 5 and the body surface electrode form a circuit signal.

[0047] Figure 3a This is a schematic diagram of the implantation tool equipped with electrodes in the second test state / retrieval and removal state according to an embodiment of the present invention. Figure 3b for Figure 3a A partially enlarged schematic diagram of the distal end of an implantation tool containing electrodes;

[0048] Please see Figure 3a , Figure 3b and Figure 12b In the second testing method, the outer sheath 1 is moved proximally to expose the distal end of the electrode 6 and the inner sheath 21 by approximately 10 mm. At this time, the first handle 22 is locked in the second locking position. In this state, the inner sheath 21 can be used as the test electrode. The inner sheath 21 is connected to the stimulator 5 via cable 27. The inner sheath 21, the stimulator 5, and the surface electrode form a circuit signal. After a successful test, the outer sheath 1 and the inner sheath 2 are locked together, i.e., the first handle 22 is locked in the second locking position. At this time, the outer sheath 1 and the inner sheath 2 are pulled out of the body together. Since the spiral fixing component 10 at the front end of the electrode 6 is already fixed in the human body, it will not move simultaneously with the outer sheath 1. After the outer sheath 1 is completely pulled out of the body, the electrode 6 completes the implantation process. If the test is unsuccessful, the first handle 22 is re-locked to the first locking position, the electrode 6 retracts into the outer sheath 1, and the outer sheath 1, the inner sheath 2, and the electrode 6 can be pulled out of the human tissue together, or a new target point can be punctured.

[0049] This invention allows for the coordinated movement of the outer sheath 1 and the inner sheath 2 to release a portion of the distal electrode head. The inner sheath 2 can also be used as a test electrode to test the stimulation effect. After a successful test, the surgeon removes the electrode lead 61 through the inner and outer sheath implantation tool 100, completely releasing the electrode 6. The distal fixing component of the electrode 6 is then released and fixed to the human tissue, ensuring that the distal electrode 6 is firmly fixed to the tissue. This reduces or even completely eliminates clinical adverse events such as electrode dislocation. Furthermore, the implantation point remains consistent with the successful test location, guaranteeing the treatment effect.

[0050] Figure 4 This is a schematic diagram of the overall structure of the outer sheath in an embodiment of the present invention; Figure 5 (a) Figure 5 (b) Figure 5 (c) is a partially enlarged schematic diagram of the distal end of the outer sheath in an embodiment of the present invention.

[0051] Please see Figure 4The outer sheath 1 includes an outer sheath tube 11 and a second handle 12. In a specific embodiment, two locking grooves 14 are symmetrically arranged on the second handle 12. Each locking groove 14 includes an axially opened sliding groove 141 and a first limiting groove 142 and a second limiting groove 143 opened circumferentially. The first limiting groove 142 and the second limiting groove 143 are both connected to the sliding groove 141. The first limiting groove 142 is located at a first locking position, and the second limiting groove 143 is located at a second locking position. The locking member on the first handle 22 can move axially along the sliding groove 141 and can be locked in the first limiting groove 142 or the second limiting groove 143. A first blade 15 is provided at the distal end of the outer sheath tube 11. The axial spacing between the first limiting groove 142 and the second limiting groove 143 is 10-15mm.

[0052] In other embodiments, each locking groove 14 further includes a third limiting groove (not shown) opened along the circumferential direction. The third limiting groove is connected to the slide groove 141. The position of the third limiting groove is a third locking position for locking the first handle 22 on the second handle 12, so as to achieve the purpose of testing different positions. Those skilled in the art can also set more different locking positions as needed, and the present invention does not limit this.

[0053] Further reading is available upon request. Figure 4 The outer sheath 11 has a length mark, namely the first mark 16, on its surface after being sanded, so that the surgeon can see the depth of the implantation tool 100 entering the human body under ultrasound.

[0054] Further, see Figure 5 (a)- Figure 5 (c) The first blade 15 set at the distal end of the outer sheath tube 11 can be set with blades of different lengths and shapes according to the needs of the human implantation target.

[0055] The inner diameter of the outer sheath tube 11 needs to accommodate the inner sheath 2 assembly with the implanted electrode 6. That is, the inner diameter of the outer sheath tube 11 needs to accommodate the fixing component 10 of the spiral structure with the distal end of the implanted electrode larger than the electrode body, or the electrode distal end fixing component 10 of other structures, and allow the inner sheath tube 21 assembly with the implanted electrode 6 to move smoothly.

[0056] Furthermore, the proximal second handle 12 of the outer sheath 1 needs to be designed for easy one-handed operation by the surgeon; please refer to [link to relevant documentation]. Figure 4 The second handle 12 is provided with two radially extending push plates 13 on its proximal end. The two push plates 13 are symmetrically arranged at the proximal end of the second handle 12 like two blades, which can be held by the operator's index and middle fingers for single-hand operation.

[0057] The outer sheath 11 can be made of 304 stainless steel or other medical alloys such as 316L. The outer sheath 11 and the inner sheath 21, where they may come into contact, need to be insulated. This can be achieved by coating the insulated surface of the outer sheath 11 with PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), or parylene, so that during testing, only the exposed distal portion of the inner sheath 21 conducts electricity, rather than the entire assembly of the outer sheath 1 and inner sheath 2 discharging together. This more realistically simulates the therapeutic effect of the distal electrode emitting a discharge stimulation signal within the body. This insulation effect can also be achieved by insulating the outer surface of the inner sheath 21, except for the distal discharge portion, while ensuring that the inner sheath 21 is not electrically connected to the outer sheath 1. The second handle 12 can be made of a relatively robust plastic, such as ABS plastic (a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S) monomers) or PC plastic (polycarbonate). Because the smaller the outer diameter of the implantation tool 100, the better, it helps to reduce puncture trauma. The outer diameter and wall thickness of the outer sheath 11 should be designed to be small enough. Considering that the outer sheath 11 also needs to be held and placed in human tissue, while meeting the requirements of strength and rigidity and delivering the electrode 6, the implantation tool 100 provided by the present invention can achieve an outer diameter of 1.27 mm (18G) or even smaller (19G, 1.07 mm diameter), which is much smaller than the outer diameter of existing implantation tools.

[0058] Figure 6a This is a schematic diagram of the structure of the inner sheath containing electrodes in an embodiment of the present invention. Figure 6b and Figure 6c This is a partially enlarged side view showing the engagement of two different structures of the second cutting edge at the distal end of the inner sheath and the spiral fixing component at the distal end of the electrode. Figure 6d and Figure 6e A magnified side view of the distal helical fixing component of the electrode at different bend angles; Figure 7 This is a schematic diagram of the overall structure of the inner sheath in an embodiment of the present invention.

[0059] Please see Figure 6a and Figure 7 The inner sheath 2 of the delivery electrode 6 is a key component in the entire implantation tool, ensuring the distal end of the electrode is firmly positioned and integrated with the tissue. The implanted electrode 6, from proximal to distal, comprises the electrode body, the stimulating electrode, and the fixation component 10. The inner diameter of the inner sheath 21 is specially designed based on the outer diameters of the electrode body and the stimulating electrode, and the gradually increasing spiral structure of the fixation component 10 at the distal end of the electrode. It can be 0.5mm-0.7mm to allow for the space between the electrode body and the stimulating electrode, enabling them to move smoothly within the inner sheath 21. Furthermore, it ensures that the gradually increasing spiral structure of the fixation component 10 at the distal end of the electrode is locked at the opening of the inner sheath 21, preventing it from entering the inner sheath 21. Figure 6b and Figure 6cAs shown; if under the action of tension at the proximal end of electrode 6 and the action of tissue muscle, the bending angle of the fixation component 10 of the distal spiral structure will be larger, such as Figure 6d and 6e As shown, the bending of the cephalic electrode is described in relatively dense and loose muscle near the nerve. That is, when the implanted electrode 6 is delivered from the inner sheath 2 to the vicinity of the nerve or other treatment target, the outer diameter of the distal spiral fixation component 10 is prevented from moving further into the inner sheath 21 at the point where the outer diameter is equal to the inner diameter of the inner sheath 21. The compression between the distal spiral fixation component 10 and the pushing force of the inner sheath 21 causes the muscle tissue to enter the spiral gap of the fixation component 10, thereby fixing the distal end of the electrode and fixing the electrode to the human body. Therefore, this design is beneficial for the spiral structure at the distal end of the electrode to hook onto the human tissue and fix it.

[0060] The inner sheath 2 assembly containing the electrode 6 needs to be smoothly inserted from the proximal end of the outer sheath 1, while allowing the outer sheath 1 assembly to move freely axially outside the inner sheath 2. Furthermore, the first handle 22 can engage with the first locking position and the second locking position on the second handle 12 of the outer sheath 1 to axially lock the inner sheath 2 to the outer sheath 1, and, as needed, cover or expose the distal end of the inner sheath 2 at the distal end of the outer sheath 1. In a specific embodiment, please also refer to... Figure 6a , Figure 4 and Figure 1a The first handle 22 is provided with a locking component that matches the locking groove 14. The locking component includes a locking shaft 24 and locking buckles 23 disposed at both ends of the locking shaft 24. The locking shaft 24 is inserted into the locking groove 14 and can move axially along the sliding groove 141, thereby allowing the outer sheath 1 to move freely axially outside the inner sheath 2. When the locking shaft 24 moves to the first limiting groove 142 or the second limiting groove 143, the circumferentially slotted upper and lower shells at the first limiting groove 142 or the second limiting groove 143 restrict the axial movement of the locking shaft 24. The size of the locking buckles 23 is larger than the width of the locking groove 14, restricting the radial movement of the locking shaft 24, thereby locking the outer sheath 1 and the inner sheath 2 together, so that the combination of the outer sheath 1 and the inner sheath 2 can be pierced into the human body or withdrawn from the human body together. When the locking shaft 24 is located in the first limiting groove 142, as Figure 1a As shown, the distal end of the inner sheath 21 and the fixing component 10 of the distal end of the electrode are located inside the outer sheath 11. When puncturing human tissue, the outer sheath 11 protects the distal electrode 6 and the spiral fixing component 10 installed in the inner sheath 21. When the locking shaft 24 is located in the second limiting groove 143, as... Figure 3a As shown, the distal end of the inner sheath 21 and the spiral fixation component 10 are exposed. At this time, the inner sheath 21 can be used as a test electrode, or the electrode 6 can be released and the implantation tool 100 can be retrieved.

[0061] Furthermore, the axial length of the inner sheath 21 is slightly shorter than that of the outer sheath 11. After the first handle 22 is locked in the first limiting groove 142, the distal end of the outer sheath 11 in the axial direction after the inner sheath 21 and the electrode 6 are combined is 1-5 mm shorter. This ensures that the distal end of the electrode 6 is concealed inside the outer sheath 11 and protected when transported together with the outer sheath 11.

[0062] Furthermore, after the first handle 22 is locked in the second limiting groove 143, a second mark 26 with a frosted finish is set on the outer surface of the inner sheath tube 21 about 10 mm outside the outer sheath tube 11, which makes it convenient for the operator to see the position where the outer sheath stops retracting proximally under ultrasound.

[0063] Furthermore, the proximal end of the first handle 22 is provided with a cable 27 for connecting to the stimulator 5, which facilitates connection to the stimulator 5 during testing.

[0064] The distal end of the inner sheath 2 can be selected from various existing blade shapes based on the expected implantation site's anatomical structure, such as... Figure 8 The second cutting edge 25 shown in (a)-8(d) includes two cutting edges in the axial direction, with an angle formed between the two cutting edges.

[0065] In the first embodiment, the distal end of the inner sheath 2 can be selected from various existing blade shapes based on the intended human anatomy, such as... Figure 8 The second cutting edge 25 shown in (a)-8(d) includes two axially oriented cutting edges with an angle between them. In the second embodiment, the distal end of the inner sheath 2 may also be flat-headed with a rounded edge and a chamfered edge, such as... Figure 9 As shown, this facilitates puncture and insertion into the human body. The inner diameter of the inner sheath 21 is clearance-fitted with the rest of the electrode 6 except for the fixing component 10, and engages with the gradually increasing spiral fixing component 10 at the distal end of the electrode 6 to lock it in place. Therefore, the distal end of the electrode 6 cannot enter the inner sheath. The inner diameter of the inner sheath 21 causes the gradually increasing diameter spiral fixing component 10 at the distal end of the electrode to lock at the distal opening of the inner sheath 21, forming an angle in its natural state. The first handle 22 at the proximal end of the inner sheath 2 is integrally molded by plastic injection molding through the inner sheath 21. Alternatively, medical adhesive can be used to bond the inner sheath 21 and the first handle 22 (separately injection molded) into an inner sheath assembly. The first handle 22 is made of relatively strong plastic materials, such as ABS plastic (a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S) monomers) and PC plastic (polycarbonate). The first handle 22 is provided with a locking element that engages with two locking positions on the second handle 12 of the outer sheath 1. One locking position is used to insert the locked state, and the other is used to test the locked state.

[0066] Figure 10a , Figure 10bThis is a schematic diagram of the parameter variables of the blade in an embodiment of the present invention; Figure 11 (a)- Figure 11 (e) is a schematic diagram of the design parameters of five different blades in the embodiments of the present invention.

[0067] Please refer to 10a. Figure 10b In this embodiment, the first cutting edge 15 and the second cutting edge 25 have similar structures. The first cutting edge 15 and the second cutting edge 25 will be collectively referred to as cutting edge 3. Preferably, cutting edge 3 includes a first cutting edge 31 and a second cutting edge 32, with the first cutting edge 31 and the second cutting edge 32 forming an angle. The total axial length of cutting edge 3 is a, and the axial length of the second cutting edge 32 is b. Further, the second cutting edge 32 is a beveled plane, forming an angle α with the axis, and the first cutting edge 31 is a beveled arc surface, with its tangent forming an angle β with the axis. Figure 11 The chamfers α of the blades shown in (a)-11(d) are 7°, 11°, 17° and 20° respectively, the total lengths a are 6.77 mm, 4.28 mm, 2.73 mm and 2.3 mm respectively, and the lengths b are 3.66 mm, 2.32 mm, 1.47 mm and 1.1 mm respectively; in this embodiment, the included angle α is 17° and the included angle β is 33°. Figure 11 The structure shown in (c) allows for the application of this puncture blade to most peripheral sites. These blade parameters can be rationally selected and adjusted according to the patient's condition and the implantation site, such as... Figure 11 (e) is a novel design of the present invention, with included angle α close to 90°, angle β of 20°, a of 1.93 mm, and b of only 0.28 mm. This structure allows the spiral fixing component 10 at the distal end of the electrode 6 to be engaged at a relatively small angle at the distal end of the inner sheath 2, thus reducing the radial force on the spiral fixing component 10 and keeping it as straight as possible in the axial direction. At the same time, it provides a certain support force for the spiral fixing component 10 during implantation, preventing it from deforming too much; it is suitable for areas with dense muscle.

[0068] Figure 12a This is a schematic diagram of the test connection in the first test method, showing the electrode connected to the stimulator via an adapter; Figure 12b This is a schematic diagram of the test connection of the inner sheath to the stimulator in the second test method.

[0069] This invention utilizes the combination of an outer sheath 1 and an inner sheath 2 to deliver the electrical stimulation signal of the stimulator 5 to the surgeon's intended stimulation point for testing. After the surgeon and patient agree that pain or other neurological disorders have been suppressed, the surgeon uses the implantation tool 100 provided by this invention to release and fix the electrode 6 to the human tissue with the special fixation component 10 at the distal end of the electrode. This ensures that the implantation point is consistent with the successful test location and allows for firm fixation of the distal stimulation electrode to the human tissue, reducing or even completely eliminating the clinical adverse event of electrode dislocation. The specific steps for delivering the electrode 6 using the implantation tool 100 provided by this invention are as follows:

[0070] 1) The surgeon diagnoses the nerve site that the patient needs to treat and locates the expected implantation point under ultrasound guidance;

[0071] 2) Lock the inner sheath 2 containing electrode 6 and the outer sheath 1 together in the insertion and puncture state. The inner sheath 2 is locked in the first locking position, such as... Figure 1a As shown, the combination of the inner sheath 2 and the outer sheath 1, which are equipped with electrodes 6, is punctured into human tissue, so that the distal tip of the steel needle in the outer sheath 1 reaches 1-5 mm further from the expected nerve implantation point, and the implantation point is 20 mm away from the expected nerve to be stimulated.

[0072] 3) Loosen the locking points of the inner and outer sheath handles, and retract the outer sheath 1 3-5mm to expose the spiral portion of the distal fixing component 10 of the electrode 6 into the human tissue. Connect the proximal end of the electrode 6 to the adapter 4 via the electrode wire 61, and connect it to the stimulator 5 to form a circuit with the surface electrode for testing. Perform the test according to the first test method, see details below. Figure 12a ;

[0073] 4) If the above method fails, use the second testing method, or directly use the second testing method: Loosen the locking point of the inner and outer sheath handles, retract the outer sheath 1 10mm from the implantation point, lock the outer sheath 1 and inner sheath 2 in the second locking position, so that approximately 10mm of the distal end of the inner sheath 2 and the distal spiral fixing component 10 of the electrode 6 are exposed in the human tissue. The inner sheath 2 is connected to the stimulator 5 via cable 27, forming a circuit with the surface electrode for testing. See details below. Figure 12b ;

[0074] 5) Evaluate whether the stimulation information emitted by the two test stimulators 5 above can meet the requirements of electrical stimulation and achieve the therapeutic effect;

[0075] 6) If the treatment effect is not achieved, move the outer sheath 1 to the first locking position at the distal end to lock the inner and outer sheath handles, withdraw the inner and outer sheaths and re-puncture, and test again; until the test meets the treatment needs of the operator and the patient.

[0076] 7) After the operator determines that the electrical stimulation treatment is satisfactory, disconnect the test cable 27 from the stimulator 5, and ensure that the handles of the inner and outer sheaths are locked in the second locking position. Figure 3aIn the second test state shown, the outer sheath 1 and inner sheath 2 are pulled out of the body together. The locked outer sheath 1 and inner sheath 2 are removed. Since the distal end of electrode 6 has a spiral structure, human tissue will be squeezed into the gap of the spiral and combined with human tissue to fix it. The inner sheath 2 has a relatively loose gap fit with electrode 6. When the inner and outer sheaths are pulled out together, electrode 6 will remain in human tissue, and the implantation will end.

[0077] In summary, the present invention solves the following technical problems in this field:

[0078] 1. Current electrical stimulation therapy often requires multiple attempts to find and test the implantation site successfully. Maintaining consistency between the successfully tested point and the final implantation point is a challenge in electrode distalization design and implantation tool design. This invention utilizes the cooperation between the inner sheath and the distal electrode structure, as well as the cooperation between the inner sheath assembly and the outer sheath, to allow the surgeon to puncture near the intended nerve. The distal electrode is then released a certain distance for testing. If the result is unsatisfactory, the surgeon can retract the released distance, withdraw the outer sheath and electrode inner sheath assembly, and re-puncture at a new location. After successful testing, the distal electrode is completely released, allowing it to integrate and fix with the human tissue. Therefore, this ensures consistency between the distal electrode implantation point and the test point, solving this difficult problem.

[0079] 2. Fixing the implanted electrode in tissue is a persistent challenge for active implantable electrode products. Furthermore, the requirements for electrode fixation vary depending on the treatment and intended implantation site anatomy, making it impossible to reuse techniques interchangeably. Electrode fixation requires not only a well-designed distal electrode structure but also seamless integration with the implantation tool. During delivery, a distal fixation structure is designed to transport and fix the distal electrode in the intended position. This invention solves this problem and enables its implementation in the product.

[0080] 3. Electrodes in neurotherapy systems are very small, with percutaneous electrodes requiring even smaller diameters (0.5mm-1.0mm). This is because a percutaneous electrode needs to be half implanted in the body, with the other half exposed through the skin. The smaller the diameter of this exposed point, the better, as a larger diameter increases the risk of infection, necessitating electrode and system removal and cessation of treatment. Therefore, percutaneous electrodes have smaller diameters than other implanted electrodes. For example, spinal stimulation electrodes have a diameter of approximately 1.3mm, and pacemaker electrodes (2.33mm-2.67mm). During distal electrode delivery and positioning, the small radial diameter of the electrode limits the internal space for the support stylet. Spinal and pacemaker electrodes can be designed with a 0.35mm space at their center to accommodate the stylet. Therefore, when delivering spinal nerve electrodes and pacemaker electrodes, the delivery tool must include and support the stylet to reach the intended implantation point. However, the implantable percutaneous electrode faces significant technical challenges during delivery, particularly in securing the distal end of the electrode to the surrounding tissue without the use of a stylet. This presents a greater challenge than other electrode implantations. This invention addresses these challenges by utilizing the combined forces of the outer sheath, the inner sheath of the delivery electrode, and the distal electrode's fixation structure. This allows for the electrode to be delivered and securely fixed to the tissue, solving the technical difficulties of electrode delivery and fixation without a stylet and enabling its implementation in a product.

[0081] 4. Percutaneous electrode implantation requires not only a small electrode diameter but also a very small implantation tool diameter, as a larger diameter results in greater trauma, and both doctors and patients prefer minimal trauma and no infection. The implantation tool for spinal stimulation electrodes is 14G (2.11mm in diameter), but achieving a percutaneous implantation tool diameter as small as 17G-18G (1.27mm-1.47mm) presents another challenge. The implantation tool provided by this invention can achieve 18G (1.27mm in diameter), or even smaller (19G, 1.07mm in diameter), solving this challenge and representing the smallest diameter implantation tool currently achievable.

[0082] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined by the claims.

Claims

1. An electrode implantation tool, wherein a fixing component is provided at the distal end of the electrode, characterized in that, The implantation tool includes an outer sheath and an inner sheath. The inner sheath includes an inner sheath tube and a first handle. The outer sheath includes an outer sheath tube and a second handle. The inner sheath tube can be inserted into the outer sheath tube. The first handle can be locked into the second handle. The second handle has at least a first locking position and a second locking position in the axial direction that can lock the first handle. The first handle can move from the first locking position to the second locking position. The fixing component is a spiral structure. The inner diameter of the inner sheath tube is smaller than the outer diameter of the spiral structure, and the inner diameter of the outer sheath tube is larger than the outer diameter of the spiral structure. Other parts of the electrode, except for the fixing component, can be inserted into the inner sheath tube. The inner sheath is inserted into the outer sheath assembly, and the first handle is locked into the second handle in the first locking position. In this state, the outer sheath is 1-5 mm longer in the axial direction than the combined axial length of the electrode and the inner sheath, so that the distal end of the inner sheath and the fixing component at the distal end of the electrode are both located inside the outer sheath. In the first test method, after the first handle is unlocked from the first locking position, the outer sheath is moved axially towards the proximal end until the distal end of the electrode exposes part of the inner sheath to form a test electrode. The test electrode, stimulator, and body surface electrode form a circuit signal. In the second test method, the outer sheath is moved towards the proximal end to expose the distal end of the electrode and the inner sheath by about 10 mm. At this time, the first handle is locked in the second locking position. In this state, the inner sheath serves as the test electrode, and the inner sheath, stimulator, and body surface electrode form a circuit signal.

2. The implantation tool as described in claim 1, characterized in that, The inner diameter of the inner sheath is 0.5mm-0.7mm, and the outer diameter of the outer sheath is 1.07mm-1.27mm.

3. The implantation tool as described in claim 1, characterized in that, The distal end of the outer sheath has a first cutting edge.

4. The implantation tool as described in claim 3, characterized in that, The first cutting edge has a first cutting edge and a second cutting edge in the axial direction from the distal end to the proximal end. The first cutting edge and the second cutting edge form an angle. The second cutting edge is a beveled plane, and the first cutting edge is a beveled arc surface.

5. The implantation tool as described in claim 1, characterized in that, The second handle has two symmetrical locking grooves. Each locking groove includes an axially extending slide groove and a first limiting groove and a second limiting groove extending circumferentially. Both the first limiting groove and the second limiting groove are connected to the slide groove. The first limiting groove is located at a first locking position, and the second limiting groove is located at a second locking position. The first handle is provided with a locking member that matches the locking groove. The locking member includes a locking shaft and locking buckles located at both ends of the locking shaft. The locking shaft is inserted into the locking groove, and the size of the locking buckles is larger than the width of the locking groove.

6. The implantation tool as described in claim 5, characterized in that, Each locking groove also includes a third limiting groove opened along the circumferential direction. The third limiting groove is connected to the sliding groove, and the position of the third limiting groove is the third locking position for locking the first handle onto the second handle.

7. The implantation tool as described in claim 5, characterized in that, When the outer sheath and the inner sheath are locked in the first locking position, the axial length of the outer sheath is 1-5 mm longer than the axial length of the inner sheath combined with the distal end of the electrode, and the axial distance between the first limiting groove and the second limiting groove is 10 mm-15 mm.

8. The implantation tool as described in claim 1, characterized in that, The distal end of the inner sheath has a second cutting edge, or the distal end of the inner sheath is flat-headed, and the distal edge of the inner sheath is chamfered circumferentially.

9. The implantation tool as described in claim 1, characterized in that, The outer surface of the outer sheath is marked with a first mark, and the outer surface of the inner sheath exposed at the distal end of the outer sheath in the test state is marked with a second mark.

10. The implantation tool as claimed in claim 1, characterized in that, Two radially extending push plates are symmetrically arranged on the proximal end of the second handle.

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