Medical implant
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- ACANDIS GMBH & CO KG
- Filing Date
- 2024-07-24
- Publication Date
- 2026-06-10
Smart Images
Figure EP2024070954_13022025_PF_FP_ABST
Abstract
Description
[0001] Medical implant
[0002] Description
[0003] The invention relates to a medical implant with a self-expanding, tubular mesh structure made of meshes. The mesh structure is formed by at least one wire, in particular a single wire, made of an X-ray-visible core material and a sheath material. Both ends of the mesh structure have closed loops. The mesh structure exerts an expansion force COF upon radial expansion. A medical implant according to the preamble of claim 1 is known, for example, from DE 202023102830 A1.
[0004] Medical implants, such as stents, are typically used to treat stenosis in blood vessels. The stent's function is to widen the narrowed blood vessel in the area of the stenosis, thus ensuring adequate blood flow. DE 202023102830 A1, mentioned above, describes a stent with a self-expanding, tubular mesh structure. However, this stent is designed for specific applications, such as the treatment of intracranial aneurysms.
[0005] The invention is therefore based on the object of providing a medical implant whose field of application is expanded.
[0006] According to the invention, this object is achieved by the subject matter of patent claims 1 and 11.
[0007] Specifically, this task is solved by a medical implant with a self-expanding, tubular mesh structure made of meshes. The mesh structure is formed by at least one wire, in particular a single wire, made of an X-ray-visible core material and a sheath material, and both ends of the mesh structure have closed loops. During radial expansion, the mesh structure exerts an expansion force COF. The expansion force COF is 0.15 at a lower insert diameter LIU of the mesh structure of 4 mm to 6 mm and a mesh size of 0.4 mm. 2 up to 0.7 mm 2 and a wire diameter of 80 pm to 90 pm, especially 85 pm, between 4 mmHg and 75 mmHg, especially a maximum of 25 mmHg. The expansion force COF is with a mean insert diameter MIU of the braid structure of 6 mm to 8 mm, a mesh size of 0.7 mm 2 up to 1.2 mm 2and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 4 mmHg and 60 mmHg, in particular a maximum of 12 mmHg, in particular a maximum of 50 mmHg. The expansion force COF is with an upper insert diameter UIU of the braid structure of 8 mm to 10 mm, a mesh size of 1.2 mm 2 up to 1.6 mm 2 and a wire diameter of 90 pm to 110 pm, in particular 100 pm, between 3 mmHg and 15 mmHg, in particular a maximum of 10 mmHg.
[0008] The invention has the advantage that the expansion force of the medical implant can be adapted to the specific application or the patient's anatomy. For this purpose, the geometry of the implant is adapted such that, upon radial expansion, the implant exerts an expansion force that enables optimal treatment of a vascular lesion. This means that, on the one hand, the expansion force must be sufficiently high to dilate a narrowed vessel. On the other hand, the expansion force must not be so high that the vessel could be injured during radial expansion of the implant. Furthermore, a high expansion force can lead to symptoms such as headaches. Therefore, various design parameters of the implant according to the invention, such as the insert diameter, the mesh size, and the wire diameter, are selected to achieve appropriate expansion forces for specific applications.
[0009] The implant is advantageously suitable for a wide range of applications. In particular, the implant is ideal for use in vessels with a diameter comparable to the transverse sinus (also called lateral sinus). Accordingly, the implant has an insert diameter range between 4 mm and 10 mm. The expansion force is adjusted within this insert diameter range using various parameters to achieve optimal treatment of the vessel. For this purpose, the implant has a lower insert diameter (LIU), a middle insert diameter (MIU), and an upper insert diameter (UIU). The lower insert diameter (LIU) forms the lower limit of the recommended insert diameter range, while the upper insert diameter (UIU) forms the upper limit of the recommended insert diameter range.The mean insert diameter (MIU) lies between the lower insert diameter (LIU) and the upper insert diameter (UIU). This means that the implanted implant can be expanded to different diameters within the intended use range, depending on the individual vessel size of the patient.
[0010] If the braid structure has an insert diameter between 4 mm and 6 mm, a wire diameter of approx. 85 pm and a mesh size between 0.4 mm 2 and 0.7 mm 2 The braided structure exerts an expansion force (COF) of between 4 mmHg and 75 mmHg upon radial expansion. The maximum expansion force is preferably 25 mmHg.
[0011] With an implant diameter range between 6 mm and 8 mm, a wire diameter of approximately 85 pm and a mesh size of 0.7 mm 2 up to 1.2 mm 2The braided structure exerts an expansion force (COF) between 4 mmHg and 60 mmHg. The expansion force is particularly preferably a maximum of 12 mmHg or a maximum of 50 mmHg.
[0012] If the insert diameter is between 8 mm and 10 mm, the wire diameter is approximately 100 pm and the mesh size is 1.2 mm 2 up to 1.6 mm 2 , the braided structure exerts an expansion force (COF) of between 3 mmHg and 15 mmHg upon radial expansion. The expansion force is particularly preferably a maximum of 10 mmHg.
[0013] The above-mentioned parameter combinations of the implant according to the invention make it possible to dilate a narrowed vessel, such as the transverse sinus, while simultaneously preventing or reducing vascular injuries and symptoms such as headaches. Preferred embodiments of the invention are specified in the subclaims.
[0014] The mesh structure is particularly preferably designed for the treatment of vascular lesions of the transverse sinus, in particular for the treatment of pulsatile tinnitus. Pulsatile tinnitus is a special type of tinnitus and refers to the perception of rhythmic noises, usually in time with the heartbeat, which is often due to an underlying vascular pathology. For example, stenosis of the transverse sinus can be the cause of pulsatile tinnitus. Therefore, it is possible to treat pulsatile tinnitus by widening the narrowed transverse sinus with an appropriate implant. The implant according to a preferred embodiment of the invention advantageously enables optimal treatment of pulsatile tinnitus. The narrowed transverse sinus can be widened without causing symptoms such as headaches.
[0015] More preferably, the at least one wire has two wire ends that are firmly connected to one another in a central region of the braided structure, in particular by welding. This is advantageous because a simple method is used to connect the free wire ends, ensuring the braided structure remains stable. Furthermore, additional components, such as crimp sleeves, for connecting the wire ends can be dispensed with.
[0016] Furthermore, the at least one wire advantageously has a braiding angle of 60° to 75° relative to a longitudinal axis of the braided structure. The braiding angle is measured between the longitudinal axis of the tubular braided structure and a wire. The braiding angle is preferably 65°. This further improves geometric stability.
[0017] In a preferred embodiment, the braided structure has a length in the axial direction between 30 mm and 60 mm, in particular between 40 mm and 50 mm. In general, the length of the braided structure or the implant can be adapted to the specific application. A braided structure length between 30 mm and 60 mm, in particular between 40 mm and 50 mm, is particularly advantageous for the treatment of vascular lesions of the transverse sinus. Preferably, the closed loops form an enlarged diameter of the braided structure with a flaring angle α relative to a longitudinal axis of the braided structure. Such a radial widening of the axial ends can, for example, avoid the risk of stent migration.
[0018] Furthermore, the flaring angle a = approximately 45° is preferably used, which positively influences the opening behavior of the implant. Another advantage is that the normal forces between the wires are kept low by a flaring angle a = approximately 45°. This can reduce or prevent material abrasion, which positively influences the braid stability and reduces the risk of fatigue fracture. Furthermore, the deliverability of the implant is improved due to lower radial forces in the flaring area.
[0019] The flaring angle α is generally measured in the resting state, i.e., when no external forces act on the implant, between the longitudinal axis of the tubular mesh structure and a loop of the expanded axial end. The flaring angle α can be understood as a conical or tapered opening angle.
[0020] The loops can preferably form large and small loops, with a small loop having a length of 57% to 81% of the length of a large loop. This means that the loops of the axial end are advantageously designed differently, in particular with different lengths. This makes it possible to improve the expansion properties of the implant in the region of the axial ends by specifically adjusting the design of individual loops, in particular the length of the loops. Furthermore, the relative movement between intersecting wires or the interaction between the wires can be reduced, thereby reducing material abrasion and consequently the risk of fatigue fracture.
[0021] The terms "large loops" and "small loops" are generally understood to mean that the large loops of one axial end of the braided structure are larger than the small loops of the same axial end. Preferably, the large loops of one axial end are of the same size. The same applies to the small loops. In other words, all large loops and all small loops, respectively, are advantageously of the same length.
[0022] Furthermore, it is preferred that the meshes be arranged in rings extending in the circumferential direction of the mesh structure, whereby the rings can each have 6 to 14 meshes, in particular 12 to 14 meshes. This allows for good stability of the mesh structure, particularly for implant insert diameters between 4 and 10 mm.
[0023] More preferably, the core material of the wire comprises platinum or a platinum alloy, with the wire having a platinum content of 5% to 20%, in particular 10%. This platinum content in the core material of the implant enables good radiopacity of the wires themselves. For example, the position of the implant can be easily determined by a surgeon during insertion of the implant or in the implanted state. The core material is particularly preferably made of platinum or a platinum alloy, as these materials have optimal radiopacity and consequently good radiopacity. Alternatively, the core material can be made of another radiopaque material, such as tungsten or gold.
[0024] The radiopaque core material can be coated with a shape-memory material. In other words, the surface of the wires can be made of a shape-memory material. The advantage here is that the shape-memory material makes the implant self-expanding or has self-expanding properties.
[0025] Such wires, which are formed from an X-ray visible core material encased in a shape memory material, are generally known as DFT wires.
[0026] Alternatively or additionally, at least one marker element can be arranged on the at least one wire of the braided structure, particularly at the ends of the braided structure. The marker element can comprise a marker sleeve that is firmly connected to the wire. Such marker sleeves have a high radiopacity, which leads to improved radiopacity. The marker sleeves are attached to the wire of the implant, particularly by crimping. This allows a stable connection between the marker sleeve and the wire to be achieved.
[0027] Furthermore, the braided structure preferably exerts a compression force RRF between 7 mmHg and 170 mmHg during radial compression.
[0028] In general, self-expanding medical implants exhibit different radial forces during the transition from the compressed state to the expanded state (expansion) than during the transition from the expanded state to the compressed state (compression). The radial force exerted by the mesh structure forms a hysteresis with a compression force RRF and an expansion force COF. A self-expanding mesh structure offers greater resistance to a radial compression process than it itself exerts when radially expanding. In other words, the compression force RRF required to compress the self-expanding implant in the expanded, particularly partially expanded, state is higher than the expansion force COF that the mesh structure automatically exerts during expansion.
[0029] Furthermore, according to claim 11, the invention relates to a medical implant with a self-expanding, tubular mesh structure made of meshes, wherein the mesh structure is formed by at least one wire, in particular a single wire, made of an X-ray-visible core material and a sheath material, and both ends of the mesh structure have closed loops, and wherein the mesh structure exerts an expansion force COF upon radial expansion. The expansion force COF is, for a lower insert diameter LIU of the mesh structure (10) of 4 mm to 6 mm, a mesh size of 0.4 mm 2 up to 0.7 mm 2 and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 4 mmHg and 75 mmHg, in particular a maximum of 25 mmHg. The expansion force COF is with a mean insert diameter MIU of the braid structure (10) of 6 mm to 8 mm, a mesh size of 0.7 mm 2 up to 1.2 mm 2and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 2 mmHg and 60 mmHg, in particular a maximum of 12 mmHg, in particular a maximum of 50 mmHg. The expansion force COF is with an upper insert diameter UIU of the braid structure (10) of 8 mm to 10 mm, a mesh size of 1.2 mm 2 up to 1.6 mm 2 and a wire diameter of 90 pm to 110 pm, in particular 100 pm, a maximum of 15 mmHg, in particular a maximum of 5 mmHg. Reference is made to the advantages explained in connection with the medical implant according to claim 1. Furthermore, the embodiments according to claims 2 to 10 are also disclosed in combination with the medical implant according to claim 11.
[0030] The invention is explained in more detail using an embodiment in conjunction with the schematic drawing.
[0031] In this shows
[0032] Fig. 1 shows an embodiment of a medical implant according to the invention with a self-expanding, tubular mesh structure.
[0033] Fig. 1 shows an exemplary embodiment of a medical implant according to the invention with a self-expanding, tubular mesh structure 10. This application involves the implant for the treatment of pulsatile tinnitus. Specifically, the implant is used to treat narrowed transverse sinus veins, which can be the cause of pulsatile tinnitus. Other applications, such as the treatment of aneurysms, are conceivable.
[0034] As shown in Fig. 1, the mesh structure 10 of the implant is formed from meshes 11. The meshes 11 form circumferential segments that continue in the axial direction of the mesh structure 10.
[0035] The implant according to Fig. 1 is also a single-wire stent, which is formed from or consists of a single wire 12. The wire 12 is braided in such a way that the mesh shape shown in Fig. 1 results. It is also possible for the stent to be formed from or consist of multiple wires 12. The wire 12 of the braided structure 10 shown in Fig. 1 is formed from an X-ray-visible core material that is encased in a sheath material. The sheath material can be, for example, a nickel-titanium alloy, such as Nitinol, or another biocompatible alloy.
[0036] Fig. 1 further shows that the two ends of the braided structure 13 form closed loops 14a, 14b that delimit the braided structure 10 in the axial direction. The loops 14a, 14b differ from the meshes 11 of the braided structure 10 in their size. Thus, it can be seen in Fig. 1 that the loops 14a, 14b form larger openings than the meshes 11 of the braided structure 10. In the embodiment according to Fig. 1, the meshes 11 have a diamond shape.
[0037] Fig. 1 further shows that the wire 12 has two wire ends that are firmly connected to each other in a central region of the braided structure 10. Specifically, the two wire ends are connected by welding. The wire ends can also be connected in another region between the ends of the braided structure 13, for example, off-center relative to the braided structure 10.
[0038] In the embodiment according to Fig. 1, the braided structure 10 has an insert diameter of between 4 mm and 6 mm. This insert diameter corresponds to a rest diameter, ie, a diameter in the unloaded state of the implant, of approximately 6 mm. Furthermore, the braided structure 10 shown in Fig. 1 has a wire 12 with a diameter of approximately 85 μm. By braiding this wire 12 accordingly, a mesh size of the braided structure 10 results between 0.4 mm 2 and 0.7 mm 2 . The mesh size corresponds to the pore size or the porosity of the mesh structure 10. Due to these parameters, ie the diameter of the mesh structure 10, the wire diameter and the mesh size, the mesh structure 10 exerts an expansion force COF between 4 mmHg and 75 mmHg, in particular a maximum of 25 mmHg, upon radial expansion.
[0039] Alternatively, it is conceivable for the mesh structure 10 to have an insert diameter between 6 mm and 8 mm. This insert diameter corresponds to a resting diameter of the implant of approximately 8 mm. If the wire 12 also has a diameter of approximately 85 mm, the mesh structure 10 exerts an expansion force COF of between 4 mmHg and 60 mmHg upon radial expansion, in particular a maximum of 12 mmHg, in particular a maximum of 50 mmHg.
[0040] Alternatively, it is conceivable for the braided structure 10 to have an insert diameter between 8 mm and 10 mm. This insert diameter corresponds to a resting diameter of the implant of approximately 10 mm. If the wire 12 also has a diameter of approximately 100 μm, the braided structure 10 exerts an expansion force COF of between 3 mmHg and 15 mmHg, in particular a maximum of 10 mmHg, upon radial expansion.
[0041] Fig. 1 further shows that the wire 12 has a braiding angle of 60° relative to a longitudinal axis L of the braided structure 10. Other braiding angles are conceivable. For example, the braiding angle can be 65° or 70°.
[0042] As shown in Fig. 1, the braided structure 10 has a length of 40 mm in the axial direction. Other lengths of the braided structure 10 are possible. For example, the braided structure 10 can have a length of 30 mm, 35 mm, 45 mm, 50 mm, 55 mm, or 60 mm.
[0043] It can be seen in Fig. 1 that the closed loops 14a, 14b form an enlargement of the diameter of the braided structure 10 with a flaring angle α relative to a longitudinal axis L of the braided structure 10. In the specific exemplary embodiment, the flaring angle α = approximately 45°. It can be seen that the flaring angle α extends essentially constantly around the longitudinal axis L and can be conical or tapered. It can also be seen that the diameter of the tubular braided structure 10 is larger in the region of the axial ends 13 than in the central region between the two axial ends of the braided structure 13. The increase in diameter occurs continuously, beginning in the region of the meshes 11 and continuously transitioning into the loops 14a, 14b.
[0044] In use, i.e. in the implanted state (not shown), the axial ends 13 are stretched or almost stretched and follow the course of the vessel. Fig. 1 shows that the loops 14a, 14b at the axial ends of the gel fence structure 13 form large and small loops 14a, 14b. It can be seen that the length of a large or small loop 14a, 14b extends from the apex of the loop 14a, 14b to the next, oppositely arranged wire crossing. In the embodiment according to Fig. 1, the loops 14a, 14b are diamond-shaped, with the length of the loops 14a, 14b being formed by the longer axis, i.e. the longitudinal axis, of the diamond.
[0045] Fig. 1 also shows that the large and small loops 14a, 14b are arranged alternately in the circumferential direction. This allows for uniform expansion behavior.
[0046] In Fig. 1 it can also be seen that the meshes 11 of the mesh structure 10 are arranged in rings which extend in the circumferential direction of the mesh structure
[0047] 10. In the embodiment according to Fig. 1, a ring has 12 stitches
[0048] 11. A different number of 11 stitches per ring is conceivable. For example, the number of 11 stitches per ring can be 6, 7, 8, 9, 10, 11, 13, or 14. A number of 12 to 14 11 stitches per ring is particularly preferred.
[0049] Furthermore, the implant according to Fig. 1 comprises a wire 12 with a core material made of platinum or a platinum alloy. Specifically, the wire 12 has a platinum content of 10%. Alternatively, it is conceivable that the wire 12 has a platinum content of 5%, 15%, or 20%. It is also conceivable that the core material is made of another, radiopaque material.
[0050] Furthermore, the X-ray-visible core material is encased in a shape-memory material. Specifically, the wire 12 in the embodiment shown in Fig. 1 is designed as a DFT wire.
[0051] Furthermore, the implant, as shown in Fig. 1, exerts a compression force RRF between 7 mmHg and 170 mmHg during radial compression.
[0052] 10 Braided structure
[0053] 11 mesh 12 wire
[0054] 12a, 12b wire ends
[0055] 13 ends of the braid structure
[0056] 14a large loops
[0057] 14b small loops L longitudinal axis a flaring angle
Claims
Claims 1. Medical implant with a self-expanding, tubular mesh structure (10) made of meshes (11), wherein the mesh structure (10) is formed by at least one wire (12), in particular a single wire (12), made of an X-ray visible core material and a sheath material and both ends (13) of the mesh structure (10) have closed loops (14a, 14b), and wherein the mesh structure (10) exerts an expansion force COF upon radial expansion, characterized in that - the expansion force COF at a lower insert diameter LIU of the braid structure (10) of 4 mm to 6 mm, a mesh size of 0.4 mm 2 up to 0.7 mm 2 and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 4 mmHg and 75 mmHg, in particular a maximum of 25 mmHg; - the expansion force COF at a mean insert diameter MIU of the braid structure (10) of 6 mm to 8 mm, a mesh size of 0.7 mm 2 up to 1.2 mm 2 and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 4 mmHg and 60 mmHg, in particular a maximum of 12 mmHg, in particular a maximum of 50 mmHg; - the expansion force COF at an upper insert diameter UIU of the braid structure (10) of 8 mm to 10 mm, a mesh size of 1.2 mm 2 up to 1.6 mm 2 and a wire diameter of 90 pm to 110 pm, in particular 100 pm, between 3 mmHg and 15 mmHg, in particular a maximum of 10 mmHg.
2. Medical implant according to claim 1, characterized in that the mesh structure is designed for the treatment of vascular lesions of the transverse sinus, in particular for the treatment of pulsatile tinnitus.
3. Medical implant according to claim 1 or 2, characterized in that the at least one wire (12) has two wire ends (12a, 12b) which are firmly connected to one another in a central region of the braid structure (10), in particular by welding.
4. Medical implant according to one of the preceding claims, characterized in that the at least one wire (12) has a braiding angle of 60° to 75°, in particular 65°, relative to a longitudinal axis (L) of the braided structure (10).
5. Medical implant according to one of the preceding claims, characterized in that the braided structure (10) has a length in the axial direction between 30 mm and 60 mm, in particular between 40 mm and 50 mm.
6. Medical implant according to one of the preceding claims, characterized in that the closed loops (14a, 14b) form an enlargement of the diameter of the braided structure (10) with a flaring angle a relative to the longitudinal axis (L) of the braided structure (10), where: a = approximately 45°.
7. Medical implant according to one of the preceding claims, characterized in that the loops (14a, 14b) form large and small loops (14a, 14b), wherein a small loop (14b) has a length of 57% to 81% of the length of a large loop (14a).
8. Medical implant according to one of the preceding claims, characterized in that the meshes (11) are arranged in rings which extend in the circumferential direction of the mesh structure (10), wherein the rings each have 6 to 14 meshes (11), in particular 12 to 14 meshes (11).
9. Medical implant according to one of the preceding claims, characterized in that the core material of the wire (12) is platinum or a platinum alloy wherein the wire has a platinum content of 5% to 20%, in particular 10%.
10. Medical implant according to one of the preceding claims, characterized in that the braided structure (10) exerts a compression force RRF between 7 mmHg and 170 mmHg during radial compression.
11. Medical implant with a self-expanding, tubular mesh structure (10) made of meshes (11), wherein the mesh structure (10) is formed by at least one wire (12), in particular a single wire (12), made of an X-ray visible core material and a sheath material and both ends (13) of the mesh structure (10) have closed loops (14a, 14b), and wherein the mesh structure (10) exerts an expansion force COF upon radial expansion, characterized in that - the expansion force COF at a lower insert diameter LIU of the braid structure (10) of 4 mm to 6 mm, a mesh size of 0.4 mm 2 up to 0.7 mm 2 and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 4 mmHg and 75 mmHg, in particular a maximum of 25 mmHg; - the expansion force COF at a mean insert diameter MIU of the braid structure (10) of 6 mm to 8 mm, a mesh size of 0.7 mm 2 up to 1.2 mm 2 and a wire diameter of 80 pm to 90 pm, in particular 85 pm, between 2 mmHg and 60 mmHg, in particular a maximum of 12 mmHg, in particular a maximum of 50 mmHg; - the expansion force COF at an upper insert diameter UIU of the braid structure (10) of 8 mm to 10 mm, a mesh size of 1.2 mm 2 up to 1.6 mm 2 and a wire diameter of 90 pm to 110 pm, in particular 100 pm, a maximum of 15 mmHg, in particular a maximum of 5 mmHg.