A detachable embolic coil system

Abstract

The present invention provides a detachable embolic spring coil system. The detachable embolic spring coil system includes a conveying device, a detaching device and an embolic spring coil; wherein: the conveying device includes a push rod, the push rod is a hollow tube, and a limiting portion is provided on the inner wall of the distal end; the detaching device includes a detaching wire and a detaching ball, the detaching wire is arranged inside the push rod, and the distal end of the detaching ball is connected to the embolic spring coil; in the limiting state, the detaching wire and the limiting portion limit the detaching ball inside the push rod; in the releasing state, the detaching ball breaks away from the restriction and detaches from the push rod from the distal end, thereby releasing the embolic spring coil. The detachable embolic spring coil system provided by the present invention can stably deliver the spring coil into the position in the human body where thrombus occlusion is required, and then easily mechanically detach the spring coil, which is simple to operate, sensitive to reaction, and will not cause damage to blood vessels.

Description

Technical Field

[0001] The invention relates to a detachable embolic spring coil system, belonging to the technical field of vascular stent preparation. Background Art

[0002] Intracranial Aneurysm (AN) is a common disease with a prevalence of 1%-5%. Because intracranial aneurysms are generally small, about 50-80% of patients' AN will not rupture in their lifetime and are not life-threatening. However, once AN ruptures, it manifests as primary subarachnoid hemorrhage (SAH) and causes acute stroke. It is a common disease that is seriously life-threatening. About 10% of acute strokes are caused by ruptured intracranial aneurysms. A survey by the World Health Organization shows that the incidence rate in China is about 2.0 / 100,000 person-years, and there are also reports of 6-20 / 100,000 people per year.

[0003] The treatments for primary subarachnoid hemorrhage caused by AN rupture are surgical clipping and endovascular embolization. With the advancement of endovascular treatment technology, the indications of this treatment method are becoming more and more extensive, and the effect is more certain. A recent multicenter collaborative large-scale case prospective study showed that the mortality and disability rates of endovascular treatment are significantly lower than those of surgical clipping, which is inseparable from the development of new technologies and new materials for endovascular treatment. Now more and more physicians and patients choose this minimally invasive and reliable treatment method.

[0004] The embolic coil is the main device for endovascular interventional treatment. It is superior to medical treatment in terms of mortality and complication rate (rebleeding rate, secondary cerebral vasospasm rate, hydrocephalus rate), and has no significant difference compared with the "gold standard" microsurgery. The latest statistics show that the proportion of interventional treatment of aneurysms in European medical centers has reached 90%, and this proportion in the United States has exceeded 50%. Interventional treatment has become the preferred method for treating aneurysms.

[0005] Existing embolic coil products mainly include delivery devices, release mechanisms and embolic coils, among which embolic coils include two-dimensional and three-dimensional coils. The three-dimensional coils are used to build a stable frame and support the aneurysm neck, and the two-dimensional coils are used in the internal space of the aneurysm to obtain a dense filling effect.

[0006] Typically, the embolic coil is placed at the distal end of the introducer sheath. When the distal end of the introducer sheath is properly positioned, the coil can be pushed out of the end of the introducer sheath by a push rod to release the coil at the desired location. This process of placing the embolic coil is performed under fluoroscopy, which helps place the coil at the desired location.

[0007] However, the existing coil designs have shortcomings such as the contradiction between the basket structure and dense packing and poor system release stability, which cannot meet the clinical needs for aneurysm embolization, increase the surgical risks for doctors, affect the treatment effect, and even endanger the patient's life.

[0008] U.S. Patent No. 5,108,407 discloses a method of retaining a spring coil at the distal end of an introducer sheath using a heat-melt releasable bond. This system uses a fiber optic cable to transmit laser energy to apply heat to the bond, which melts the connection to release the spring coil from the distal end of the introducer sheath.

[0009] US Patent Application No. 5895391A discloses another device for mechanically releasing a spring coil, comprising a manipulation wire, a prototype sphere fixed to the embolic spring coil, and a locking device at the distal end of a delivery tube. The sphere and the distal end of the manipulation wire are assembled in the locking device to fix the push rod and the embolic coil, and the circular sphere is released by pulling the manipulation wire, thereby releasing the embolic spring coil.

[0010] Generally speaking, there are four main ways to release the coil: hydrolysis, electrolysis, heat-melt and mechanical release. Hydrolysis is to add solvent into the delivery rod and use the dissolving property to release the coil. It has the problem of unstable release and the injection of solvent is easy to increase the blood vessel pressure. If the amount of solvent injected is insufficient and the position of the coil release is not reached, it is difficult to achieve release. Electrolysis is to weld the coil and the guide wire together by electric welding. After the welding is cooled, the welding part will be uneven, which is easy to generate a relatively high voltage, resulting in the time of electrolysis release of the coil from the introduction sheath is not easy to control. The time of electrolysis release ranges from 30 seconds to several minutes. Heat-melt release requires the introduction of current, wires and electrodes, etc. It generates heat through electrical energy. When the heat reaches a certain level, the thermal fuse is melted to achieve the release of the coil. Smoke will be generated during hot melting, causing local damage in the human body and increasing the pain of the patient. The current mainstream method of mechanical release is the loop type, that is, adding a movable connecting rod with a spherical feature at the end. The head end of the movable connecting rod is connected to the spring coil. The release wire is assembled with the movable connecting rod and placed into the delivery sheath. The spring coil is released by withdrawing the release wire.

[0011] The art still lacks an embolization coil system with simple structure, easy operation, safety and reliability. Summary of the invention

[0012] The purpose of the present invention is to provide a safe and reliable detachable embolic coil system, thereby solving the shortcomings of existing embolic coil products such as complex structure and inconvenient operation.

[0013] To achieve the above-mentioned object, the present invention provides a detachable embolic coil system, wherein the detachable embolic coil system comprises a delivery device, a detachment device and an embolic coil; wherein:

[0014] The conveying device comprises a push rod, which is in the shape of a hollow tube and has a limiting portion on the inner wall of the distal end;

[0015] The release device comprises a release wire and a release ball, wherein the release wire is arranged inside the push rod, and the distal end of the release ball is connected to the embolization spring coil;

[0016] In the limited state, the release wire and the limit part limit the release ball inside the push rod;

[0017] In the released state, the release ball is freed from the restriction and the push rod from the far end, thereby releasing the embolic spring coil.

[0018] In the present invention, "proximal end" refers to the end of the device tending to be outside the body, and "distal end" refers to the end of the device tending to be inside the body or close to the embolic spring coil, or in other words, the side close to the thrombus during use.

[0019] In the above-mentioned detachable embolic spring coil system, the delivery device is mainly used to deliver the embolic spring coil to the required position, and at the same time, cooperate with the release wire, the limit part, etc. to limit the release ball in the limited state. The specific limiting method can be: using the release wire to squeeze the release ball between the inner wall of the push rod and the limit part, so that it cannot move and cannot be separated from the push rod to achieve limited fixation; the specific limiting method is not limited to this. The delivery device is provided with a push rod. The push rod is actually a tube containing a release wire and a release ball at the distal end. The push rod is generally divided into three sections: the proximal end is a simple tubular shape; the diameter and wall thickness of the distal end can be reduced, and a spiral coil can be embedded in the tube wall to form a microstructure of the distal section of the push rod to increase flexibility and maintain strength; between the proximal end and the distal end is a transition section connecting the two sections, and due to the different diameters of the proximal and distal ends, the transition section is conical.

[0020] In the above-mentioned detachable embolic spring coil system, the release device is mainly used to achieve limiting and release, so as to release the embolic spring coil. The release device includes components such as a release wire and a release ball, wherein the release ball is limited inside the push rod, and the distal end of the release ball can be connected to the embolic spring coil by laser, hot melt or the like. After the embolic spring coil is transported to the position where it needs to be released, the release wire is pulled, and the release ball is released, thereby releasing the embolic spring coil. The release ball can be selected to have an appropriate spherical shape, and the part connected to the embolic spring coil can be realized by a straight rod, but is not limited to this method. The maximum outer diameter of the release ball should be smaller than the inner diameter of the limiting part set at the distal end of the push rod, so that the release ball can leave the push rod.

[0021] In the above-mentioned detachable embolic spring coil system, the limiting part is used to fix the release ball before the spring coil is released to prevent the spring coil from being released by mistake.

[0022] Preferably, the limiting portion is arranged on the inner wall of the distal end of the push rod by welding and / or bonding. The limiting portion can be of any suitable shape, preferably a rectangular interface, and its size should be adapted to the size of the release ball, so that the release ball can be restricted in the limiting state and can be smoothly pushed out from the inside of the push rod in the released state.

[0023] In the above-mentioned detachable embolic coil system, preferably, the delivery device further comprises an introduction sheath, the distal end of the push rod is inserted into the proximal end of the introduction sheath, and the embolic coil is arranged inside the introduction sheath. The introduction sheath plays a role in assisting the introduction of the detachable embolic coil system into the microcatheter in application, specifically placing and protecting the coil. During the operation, the push rod and the connected introduction sheath enter the body through the microcatheter (such as a nerve catheter) to reach the corresponding part (such as the hemangioma part), and the push rod pushes the coil placed in the introduction sheath to make the coil enter the desired part, and then withdraws from the proximal end together with the push rod and the introduction sheath.

[0024] In the above-mentioned detachable embolic spring coil system, preferably, the release device further includes a pre-compressed elastic coil, and during the assembly process, the elastic coil is in a compressed state. The pre-compressed elastic coil is arranged in the push rod, and the proximal end of the pre-compressed elastic coil is fixed in the push rod, and the distal end of the pre-compressed elastic coil is close to the proximal end of the release ball; in the release state, the release ball is freed from the restriction, and the pre-compressed elastic coil is relaxed to push the release ball out of the push rod, thereby releasing the embolic spring coil. According to a specific embodiment of the present invention, in this case, preferably, the elastic coil is coaxially welded with the push rod, and a limiting portion (such as an arched washer) is provided at both ends of the elastic coil. The proximal end of the elastic coil is fixedly connected to the push tube as a whole, and through the assembly gap and pre-compression force, the elastic coil will only pop out to the distal end after being released, and will not get stuck in design. By adopting the "coaxial welding" method, it can be ensured that the push rod and the elastic coil are coaxial in geometric position relationship, so that the force on the release ball at any position is the same, that is, uniform force.

[0025] In the above-mentioned detachable embolic spring coil system, preferably, the detachment device further comprises a pre-stretched elastic coil, and during the assembly process, the elastic coil is in a stretched state. The proximal end of the pre-stretched elastic coil is connected to the distal end of the detachment ball, and the distal end of the pre-stretched elastic coil is connected to the proximal end of the embolic spring coil; in the released state, the detachment ball is freed from the restriction, and the pre-stretched elastic coil contracts to pull the detachment ball out of the push rod, thereby releasing the embolic spring coil.

[0026] In the above-mentioned detachable embolic spring coil system, preferably, a stopper is provided at the proximal end of the inner cavity of the embolic spring coil; the release device also includes a pre-compressed elastic coil, and during the assembly process, the elastic coil is in a compressed state. The proximal end of the pre-compressed elastic coil is connected to the distal end of the push rod, and the distal end of the pre-compressed elastic coil is close to the stopper; in the release state, the release ball is freed from the restriction, and the pre-compressed elastic coil expands to push the release ball out of the push rod, thereby releasing the embolic spring coil.

[0027] In the above-mentioned detachable embolic spring coil system, preferably, the wire diameter of the elastic coil is 0.01 mm-0.3 mm.

[0028] In the above-mentioned detachable embolic coil system, preferably, in a compressed state, the elastic coil is in a tight state; when relaxed after release, the pitch of the elastic coil is restored to 1-5 times of the wire diameter.

[0029] In the above-mentioned detachable embolic coil system, preferably, the elastic coil is made of nickel-titanium alloy, stainless steel or polymer material. The elastic coil is preferably made by cutting and winding.

[0030] The detachable embolic coil system provided by the present invention can stably deliver the coil into the position in the human body where thrombus occlusion is required, and then easily mechanically detach the coil. It is simple to operate, responsive, and will not cause damage to blood vessels. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the detachable embolic coil system of Example 1.

[0032] Figure 2 It is a schematic diagram of the structure of the limit block at the far end of the push rod.

[0033] Figure 3 This is a schematic structural diagram of the detachable embolic coil system of Example 2.

[0034] Figure 4 This is a schematic diagram of pulling the release wire during release in Example 2.

[0035] Figure 5 This is a schematic diagram of the release ball after the constraint is removed during release in Example 2.

[0036] Figure 6 Schematic diagram of the compressed state and the relaxed state of the elastic coil in Example 2.

[0037] Figure 7 This is a schematic diagram of Example 2 after the embolic coil is released.

[0038] Figure 8 Schematic diagram of the structure of the detachable embolic coil system of Example 3.

[0039] Fig. 9 This is a schematic diagram of pulling the release wire during release in Example 3.

[0040] Fig.10 This is a schematic diagram of Example 3 after the embolic coil is released.

[0041] Fig.11 Schematic diagram of the structure of the detachable embolic coil system of Example 4.

[0042] Description of main figures:

[0043] Embolic spring coil 1; push rod 2; introduction sheath 3; limiter 4; release wire 5, release ball 6; pre-compressed elastic coil 7; pre-stretched elastic coil 8; stopper 9; pre-compressed elastic coil 10 DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0045] Example 1

[0046] This embodiment provides a detachable embolic coil system, the structure of which is as follows: Figure 1 The detachable embolic coil system comprises: a delivery device, a detachment device and an embolic coil 1; wherein:

[0047] The delivery device includes a push rod 2 and an introduction sheath 3; the push rod 2 is a hollow tube, and a limit portion 4 (such as Figure 2 As shown), the distal end of the push rod 2 is inserted into the proximal end of the introduction sheath 3, and the embolic spring coil 1 is arranged in the introduction sheath 3;

[0048] The release device comprises a release wire 5 and a release ball 6. The release wire 5 is arranged inside the push rod 2. The distal end of the release ball 6 is connected to the embolization spring coil 1.

[0049] In the limited state, the release wire 5 and the limit part 4 limit the release ball 6 inside the push rod 2;

[0050] When releasing, the release wire 5 is pulled at the proximal end of the push rod 2, and the release ball 6 is released from the restriction and unlocked. Under the influence of factors such as blood flow dynamics or gravity, the release ball 6 moves to the distal end of the push rod 2 and is separated from the push rod 2 from the distal end, thereby being released from the delivery device to achieve the release of the embolic spring coil 1. The release method of this embodiment is a natural separation without active release.

[0051] Example 2

[0052] This embodiment provides a detachable embolic coil system, the structure of which is as follows: Figure 3 The detachable embolic coil system comprises: a delivery device, a detachment device and an embolic coil 1; wherein:

[0053] The delivery device includes a push rod 2 and an introduction sheath 3 (not shown in the figure); the push rod 2 is a hollow tube, and a limit portion 4 is provided on the inner wall of the distal end thereof. The distal end of the push rod 2 is inserted into the proximal end of the introduction sheath 3, and the embolization spring coil 1 is arranged in the introduction sheath 3;

[0054] The release device includes a release wire 5, a release ball 6, and a pre-compressed elastic coil 7. The release wire 5 is arranged inside the push rod 2, and the distal end of the release ball 6 is connected to the embolization spring coil 1; the pre-compressed elastic coil 7 is arranged in the push rod 2, and a pre-compression force is given to the elastic coil by assembly, and its proximal end is fixed in the push rod 2 (coaxially welded with the push rod 2), and the distal end is close to the proximal end of the release ball 6, and the two are only close together, and are not fixedly connected together; and arch washers are respectively provided at both ends of the pre-compressed elastic coil 7, and the material of the pre-compressed elastic coil 7 is preferably nickel-titanium, stainless steel or polymer materials;

[0055] In the limited state, the release wire 5 and the limit part 4 limit the release ball 6 inside the push rod 2, and the pre-compressed elastic coil 7 is also limited and in a compressed state, shrinking inside the push rod 2;

[0056] When releasing, the release wire 5 is pulled at the proximal end of the push rod 2 ( Figure 4 ), the release ball 6 is released from the restriction and unlocked, and the pre-compressed elastic coil 7 also loses the restriction ( Figure 5 ), gradually relax ( Figure 6 ), push the release ball 6 out of the push rod 2 ( Figure 7 ), thereby disengaging from the delivery device and achieving the release of the embolic spring coil 1.

[0057] Example 3

[0058] This embodiment provides a detachable embolic coil system, the structure of which is as follows: Figure 8The detachable embolic coil system comprises: a delivery device, a detachment device and an embolic coil 1; wherein:

[0059] The delivery device includes a push rod 2 and an introduction sheath 3; the push rod 2 is a hollow tube, and a limit portion 4 is provided on the inner wall of the distal end thereof, the distal end of the push rod 2 is inserted into the proximal end of the introduction sheath 3, and the embolic spring coil 1 is arranged in the introduction sheath 3;

[0060] The release device comprises a release wire 5, a release ball 6, and a pre-stretched elastic coil 8. The release wire 5 is arranged inside the push rod 2, and the distal end of the release ball 6 is connected to the embolic spring coil 1; the pre-stretched elastic coil 8 is located inside the embolic spring coil 1, and its proximal end is fixedly connected to the distal end of the release ball 6, and the distal end of the pre-stretched elastic coil 8 is connected to the proximal end of the embolic spring coil 1;

[0061] In the limited state, the release wire 5 and the limit part 4 limit the release ball 6 inside the push rod 2, and the pre-stretched elastic coil 8 is also limited and in a stretched state, located inside the embolic spring coil 1;

[0062] When releasing, the release wire 5 is pulled at the proximal end of the push rod 2, the release ball 6 is released from the restriction and unlocked, and the pre-stretched elastic coil 8 also loses the restriction ( Fig. 9 ), gradually shrinks, pulls the release ball 6 out of the push rod 2, and releases it from the conveying device ( Fig.10 ) to achieve the release of the embolic spring coil 1.

[0063] Example 4

[0064] This embodiment provides a detachable embolic coil system, the structure of which is as follows: Fig.11 The detachable embolic coil system comprises: a delivery device, a detachment device and an embolic coil 1; wherein:

[0065] The delivery device includes a push rod 2 and an introduction sheath 3; the push rod 2 is a hollow tube, and a limit portion 4 is provided on the inner wall of the distal end thereof, the distal end of the push rod 2 is inserted into the proximal end of the introduction sheath 3, and the embolic spring coil 1 is arranged in the introduction sheath 3;

[0066] A stopper 9 is provided at the proximal end of the inner cavity of the embolic spring coil 1;

[0067] The release device comprises a release wire 5, a release ball 6, and a pre-compressed elastic coil 10. The release wire 5 is arranged inside the push rod 2, and the distal end of the release ball 6 is connected to the embolic spring coil 1; the proximal end of the pre-compressed elastic coil 10 is fixedly connected to the distal end of the release ball 6, and the distal end is close to the stopper 9;

[0068] In the limited state, the release wire 5 and the limit part 4 limit the release ball 6 inside the push rod 2, and the pre-compressed elastic coil 10 is also limited between the push rod 2 and the embolic spring coil 1 and is in a compressed state;

[0069] When releasing, the release wire 5 is pulled at the proximal end of the push rod 2, the release ball 6 is released from the restriction and unlocked, and the pre-compressed elastic coil 10 also loses the restriction and gradually relaxes, pushing the block 9 away to release it from the delivery device, thereby achieving the release of the embolic spring coil 1.

[0070] The devices provided in Examples 1-4 can stably deliver the spring coil into the location in the human body where thrombus occlusion is required, and then easily mechanically release the spring coil. The operation is simple, the response is sensitive, and no damage is caused to the blood vessels.

Claims

1. A detachable embolic coil system, characterized in that: The detachable embolic coil system comprises a delivery device, a detachment device and an embolic coil; wherein: The conveying device comprises a push rod, which is in the shape of a hollow tube and has a limiting portion on the inner wall of the distal end; The release device comprises a release wire and a release ball, wherein the release wire is arranged inside the push rod, and the distal end of the release ball is connected to the embolization spring coil; The release device further comprises a pre-compressed elastic coil or a pre-stretched elastic coil; the pre-compressed elastic coil is arranged in the pushing rod, the proximal end of the pre-compressed elastic coil is fixed in the pushing rod, and the proximal end of the pre-compressed elastic coil is close to the distal end of the release ball; the proximal end of the pre-stretched elastic coil is connected to the distal end of the release ball, and the distal end of the pre-stretched elastic coil is connected to the proximal end of the embolic spring coil; In the limited state, the release wire and the limit part limit the release ball inside the push rod; In the released state, the release ball is freed from the restriction, the pre-compressed elastic coil is relaxed to push the release ball out of the push rod, and the release ball is separated from the push rod from the distal end, thereby releasing the embolic spring coil; In the released state, the release ball is freed from the restriction, the pre-stretched elastic coil contracts to pull the release ball out of the push rod, and the release ball is separated from the push rod from the far end, thereby releasing the embolic spring coil.

2. The detachable embolic coil system according to claim 1, characterized in that: The limiting portion is arranged on the inner wall of the distal end of the pushing rod by welding and / or bonding.

3. The detachable embolic coil system according to claim 1, characterized in that: The delivery device also includes an introduction sheath, the distal end of the push rod is inserted into the proximal end of the introduction sheath, and the embolization spring coil is arranged inside the introduction sheath.

4. The detachable embolic coil system according to claim 1, characterized in that: The elastic coil is coaxially welded with the pushing rod, and limiting parts are provided at both ends of the elastic coil.

5. The detachable embolic coil system according to claim 1, characterized in that: A stopper is provided at the proximal end of the inner cavity of the embolic spring coil; The proximal end of the pre-compressed elastic coil is connected to the distal end of the pushing rod, and the distal end of the pre-compressed elastic coil is close to the stopper.

6. The detachable embolic coil system according to claim 1, characterized in that: The wire diameter of the elastic coil is 0.01mm-0.3mm.

7. The detachable embolic coil system according to claim 6, characterized in that: In a compressed state, the elastic coil is in a tight state; when it is relaxed after being released, the pitch of the elastic coil is restored to 1-5 times of the wire diameter.

8. The detachable embolic coil system according to any one of claims 1 to 7, characterized in that: The elastic coil is made of nickel-titanium alloy, stainless steel or polymer material.

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