Disclosure of Invention
The present application relates to a micromachined guidewire that uses a micromachined hypotube (hypotubes) to achieve a smaller bend radius when changing the shape of the guidewire as needed while balancing the complex bending stiffness, tensile strength, and torsional strength requirements of the human vasculature.
The application adopts a tubular hypotube structure, and removes partial materials from the tubular structure in a specific pattern, thereby enhancing the flexibility of the tubular structure, providing space for further bending of the tubular structure, realizing smaller bending radius of the guide wire, and avoiding collision at a turning position when the guide wire passes through a blood vessel with a far-end and bending in the intracranial way because of the enhanced flexibility and smaller bending radius of the tubular structure when the guide wire is used, so that the bending radius of the guide wire is too large to reach the expected lesion position.
Because the guidewire has enhanced flexibility, the approach of the guidewire to the vessel wall can be reduced, thereby reducing friction during delivery. This is particularly advantageous when delivered to intracranial vessels, since the intracranial vessels are not protected by muscle traction, resulting in a more fragile structure, and if the guidewire is less flexible, there is a higher likelihood that the vessel will puncture or straighten and thereby damage the nerve. The guide wire of the application adopts the hypotube, and a part of materials of the hypotube are removed to form the concave part with the cross section in a trapezoid shape or a triangle shape and the like, and the width of the concave part gradually decreases from the outside to the inside, so the flexibility is higher, thereby being capable of conforming to the tortuous anatomical structure of a blood vessel and further reducing the friction force, traction and damage to nerves of the blood vessel.
An embodiment of the present application provides a guidewire, comprising: a core wire that tapers at a distal end portion as it extends toward a distal end side; a coil surrounding the distal end of the core wire; and a hypotube that is sleeved over the coil and a portion of the core wire, wherein the hypotube comprises: a body portion formed in a tubular shape to be fitted over the coil and a portion of the core wire; a plurality of concave portions each extending in a circumferential direction of the body portion in the body portion and arranged at intervals in an axial direction of the body portion, wherein the plurality of concave portions are formed so as to be recessed in a manner of decreasing in width from an outer circumferential surface of the body portion toward a radial inner side, the width being a distance between opposite side surfaces of the concave portions in an axial direction of the hypotube, wherein a portion of the body portion located between adjacent concave portions in the plurality of concave portions is formed as a ring portion, the concave portions decreasing in width from the outer circumferential surface of the body portion toward the radial inner side when the distal end portion of the guidewire is bent provide additional spaces for the adjacent ring portions to come close to each other so as to avoid the adjacent ring portions from abutting against each other, and wherein a maximum included angle between the opposite side surfaces of the concave portions in the axial direction of the hypotube is in a range of 5 ° to 25 ° in a sectional view passing through an axial center of the hypotube.
In one embodiment, in a sectional view through the axis of the hypotube, a maximum included angle between the opposite side surfaces of the concave portion in the axial direction of the hypotube is in a range of 10 ° to 20 °.
In one embodiment, wherein a maximum included angle between the opposite side surfaces of the recess in the axial direction of the hypotube is 5 °, 10 °, 15 °, 20 °, or 25 °.
In one embodiment, each of the plurality of recesses is formed as a through opening from an outer peripheral surface of the body portion to an inner peripheral surface of the body portion.
In one embodiment, the opening is formed to have a trapezoidal cross-sectional shape in a cross-sectional view through the axis of the hypotube.
In one embodiment, each recess of the plurality of recesses is formed as a non-penetrating aperture from an outer peripheral surface of the body portion to an interior of the body portion.
In one embodiment, the aperture is formed to have a triangular cross-sectional shape in a cross-sectional view through the axis of the hypotube.
In one embodiment, the plurality of concave portions includes a plurality of first concave portions and a plurality of second concave portions alternately arranged in an axial direction of the hypotube, wherein the plurality of first concave portions and the plurality of second concave portions are formed at different positions in a circumferential direction of the body portion.
In one embodiment, wherein each of the plurality of first recesses includes a plurality of first sub-recesses disposed at intervals along a circumferential direction of the hypotube, the plurality of first sub-recesses being equally spaced apart from each other and formed in equal length, and wherein each of the plurality of second recesses includes a plurality of second sub-recesses disposed at intervals along the circumferential direction of the body portion, the plurality of second sub-recesses being equally spaced apart from each other and formed in equal length.
In one embodiment, the recess is formed by laser cutting to remove a portion of the body portion.
In one embodiment, the recess is formed by etching away a portion of the body portion.
In one embodiment, the concave portion is formed to have a trapezoidal sectional shape in a sectional view through the axis of the hypotube.
In one embodiment, the concave portion is formed to have a triangular sectional shape in a sectional view through the axis of the hypotube.
In one embodiment, in a sectional view through the axis of the hypotube, the both side surfaces of the concave portion that are opposite in the axial direction of the hypotube have a curved shape.
In one embodiment, in a sectional view through the axis of the hypotube, the both side surfaces of the concave portion that are opposite in the axial direction of the hypotube have a stepped shape.
Detailed Description
Embodiments of the present application are described below with reference to the drawings in the present application. It should be understood that the embodiments described below with reference to the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application, and the technical solutions of the embodiments of the present application are not limited.
As shown in fig. 1, a guide wire 100 according to an embodiment of the present application includes a coil 110, a hypotube 120, and a core wire 130. Wherein the core wire 130 may be formed in a rod shape by integral molding, and the core wire 130 is tapered at a distal end portion as it extends toward a distal end side, so that the distal end portion is formed in a substantially tapered shape. In embodiments of the present application, the core wire 130 may be made of any one or combination of stainless steel, nickel titanium, or other metals. Wherein the distal end may be defined as the leading end of the guidewire leading into the interior of the vessel and the proximal end may be defined as the opposite end of the distal end.
The coil 110 surrounds a generally tapered distal portion of the core wire 130. In embodiments of the present application, the coil 110 may be made of any one or combination of stainless steel, nickel titanium, platinum tungsten, platinum gold, or other metals. Preferably, the coil 110 may be formed in a single-layer or multi-layer structure.
The hypotube 120 is formed in a tubular shape and is sleeved on a portion of the coil 110 and the core wire 130, and may be fixed to each other by welding, bonding, or the like. Preferably, hypotube 120 may be made of any one or combination of stainless steel, nitinol, or other metals.
Preferably, the outermost side of the guidewire 100 may be coated with a hydrophilic coating and/or a hydrophobic coating.
Referring to fig. 2, a hypotube 1 (e.g., hypotube 120 described previously) includes: a body portion 10, the body portion 10 being formed in a tubular shape; and a plurality of recesses formed in the body portion 10.
The body portion 10 is formed in a hollow tubular shape that is ideal for medical devices because the tubular structure provides a structure with an inner lumen and is capable of providing a maximum moment arm for torsional manipulation. The material of the body portion 10 includes, but is not limited to, stainless steel, nitinol, or other metallic materials. The material of the body portion 10 may also be a polymer, such as PEEK.
The outer diameter and wall thickness (inner diameter) of the tubular structure of the body portion 10 may be selected to have different base characteristics such as torque response and stiffness. For example, if the outer diameter is increased and the wall thickness is reduced, the tubular structure may achieve an improved torque response while having the same bending stiffness at the expense of some mechanical strength.
Each of the plurality of recesses is formed in the body portion 10 to extend in the circumferential direction of the body portion 10 to form an elongated groove extending along the circumferential direction of the body portion 11.
Preferably, the plurality of concave portions 10 are formed so as to include a plurality of first concave portions 11 and a plurality of second concave portions 12 alternately arranged along the axial direction of the body portion 10. As shown in fig. 2, the plurality of first concave portions 11 and the plurality of second concave portions 12 are alternately arranged with each other along the axis of the body portion 11, so that a ring portion 20 is formed between the adjacent first concave portions and second concave portions.
Preferably, each of the plurality of first recesses 11 includes a plurality of first sub-recesses spaced apart from each other in the circumferential direction, that is, a plurality of first sub-recesses formed in segments. Further preferably, the plurality of first sub-recesses are provided at equal intervals and equal length. As an example, referring to fig. 2, each first concave portion 11 includes two first sub-concave portions 11 (1) and 11 (2) disposed opposite to each other in the circumferential direction, and the two first sub-concave portions 11 (1) and 11 (2) are disposed on the body portion 10 at equal intervals and equal lengths.
The illustration of fig. 2 is merely an example and is not limited thereto. For example, the plurality of first sub-recesses may be formed in 3 or more.
Similar to the plurality of first recesses 11, preferably, each of the plurality of second recesses 12 includes a plurality of second sub-recesses spaced apart from each other in the circumferential direction. Further preferably, the plurality of second sub-recesses are provided at equal intervals and equal length. As an example, referring to fig. 2, each of the second concave portions 12 includes two second sub-concave portions disposed opposite to each other in the circumferential direction, and the two second sub-concave portions are disposed on the body portion 10 at equal intervals and with equal length.
Preferably, in the case where each of the plurality of first recesses 11 and/or the plurality of second recesses 12 includes a plurality of sub-recesses, the hypotube 1 further includes a beam 13 formed between the plurality of sub-recesses in the circumferential direction. The plurality of sub-recesses are spaced apart from each other in the circumferential direction by the beam 13. Here, liang Dingyi to be formed between the plurality of first sub-recesses (e.g., the first sub-recesses 11 (1) and 11 (2)) is a beam 13a (not shown), and Liang Dingyi to be formed between the plurality of second sub-recesses of the second recess 12 is a beam 13b (not shown).
Preferably, the plurality of first concave portions 11 are formed at positions different from the plurality of second concave portions 12 in the circumferential direction of the body portion 10 of the hypotube 1. Further preferably, the extension lengths of the plurality of first recesses 11 and the plurality of second recesses 12 in the circumferential direction are designed such that: when the guide wire is viewed in the axial direction, the beam 13a overlaps at least a portion of the recess (second sub-recess) forming the adjacent beam 13b, and the beam 13b overlaps at least a portion of the recess (first sub-recess) forming the adjacent beam 13a, so that a portion overlapping each other is not generated between any adjacent beams.
When the guide wire is bent such that the recess portions are located at the inner side of the bend, the recess portions at the inner side provide spaces (hereinafter, referred to as "contraction spaces") for adjacent ring portions 20 to be further close to each other and the ring portions 20 at opposite sides to be separated from each other, thereby achieving a smaller bending radius of the guide wire, improving the flexibility of the guide wire while maintaining torsional and bending rigidity, thereby achieving a balance among flexibility, tensile strength, and torque transmission of the tubular structure of the guide wire. Also, as the adjacent loop portions 20 at the inner side are further bent until they abut against each other, the adjacent loop portions 20 abutting against each other prevent kinking of the tubular structure of the guide wire and bending beyond a desired angle.
By providing the lengths of the plurality of first concave portions 11 and the plurality of second concave portions 12 as described above, concave portions are formed in any section passing through the axial center of the cylindrical structure of the hypotube 1. Thus, regardless of whether the hypotube 1 is bent in any direction, a recess providing further constricting space for bending is formed between the loops 20 at the inside of the bend, thereby facilitating the ability of the guidewire to achieve a smaller bend radius without kinking in any direction, increasing the flexibility of the guidewire, and thus achieving a balance between flexibility, tensile strength and torque transmission of the tubular structure of the guidewire.
As a comparative example, each of the concave portions 11 and 12 is formed so as to be recessed from the outer peripheral surface of the body portion 10 perpendicularly toward the radial inside, as shown in (b) of fig. 5.
However, in the embodiment of the present application, each of the concave portions 11 and 12 is recessed in the body portion 10 in such a manner as to decrease in width from the outer peripheral surface of the body portion 10 toward the radially inner side, the width being the distance between the opposite side surfaces of the concave portion in the axial direction of the hypotube.
Thus, as compared to the manner in which the recess in the comparative example shown in fig. 5 (b) is recessed perpendicularly to the outer and/or inner surface of the body portion, since the recess of the embodiment of the present application is gradually reduced in width radially inward (as shown in fig. 5 (a)), it is possible to further provide the adjacent ring portions 20 with additional shrink spaces for approaching each other, thereby allowing the tubular structure of the body portion of the guide wire to achieve a smaller bending radius without affecting the overall mechanical strength. Referring to fig. 5 (a) and 5 (b), the significantly reduced width recess shown in fig. 5 (a) may provide a larger (additional) constricted space for the ring portions (space for approaching each other), and thus may be bent at a smaller bending radius than the vertical recess of fig. 5 (b), avoiding the adjacent ring portions from abutting each other.
In one embodiment of the present application, referring to fig. 3, fig. 3 shows a cross-section taken along the line A-A' passing through the axis of the hypotube 1 shown in fig. 2.
As shown in fig. 3, the plurality of first concave portions 11 and the plurality of second concave portions 12 are alternately arranged in the axial direction (left-right direction in the drawing) of the hypotube 1. Each recess is formed as a through opening from the outer peripheral surface 31 to the inner peripheral surface 32 of the body portion 10, and the cross section of each recess is formed to gradually decrease in width from the outer peripheral surface 31 to the inner peripheral surface 32 of the body portion 10, wherein the width refers to the dimension of the recess in the axial direction of the guide wire.
In the embodiment shown in fig. 3, the cross section of each recess is formed in a trapezoidal shape gradually decreasing in width from the outer peripheral surface to the inner peripheral surface as described above.
Preferably, the recess has a maximum included angle X (refer to fig. 4) between both side surfaces opposite to each other in the axial direction of the guide wire (hypotube), which is the maximum value of the included angle between the corresponding positions of the both side surfaces. The magnitude of the maximum included angle may be appropriately set according to the circumstances, and for example, the magnitude of the included angle X may be appropriately set as an optimum angle according to the outer diameter of the tubular structure of the body portion 10, the width of the recess 10, and the like.
Specifically, when the maximum included angle X is larger, more material is removed from the body portion to form a recess with a larger width, so that the strength of the whole hypotube is affected, and the tensile strength, torque transmission and the like of the hypotube may be affected; and when the maximum angle X is smaller, smaller material is removed at the body portion to form a recess having a smaller width, the flexibility of the hypotube is reduced and the contraction space of the ring portion is reduced to facilitate collision. Therefore, the angle of the maximum included angle X should be within a proper range to ensure a balance of properties such as flexibility, tensile strength, and torque transmission.
Therefore, it is preferable that the maximum included angle X between the opposite side surfaces of the concave portion in the axial direction of the guide wire is in the range of 5 ° to 25 °. Further preferably, the maximum angle is in the range of 10 ° to 20 °. In an embodiment of the present application, the maximum included angle may be 5 °,10 °,15 °, 20 °, or 25 °.
However, the present application is not limited thereto. For example, each recess may be formed as a non-penetrating aperture from the outer peripheral surface 31 of the body portion 10 to the inside of the body portion (i.e., the recess does not reach the inner peripheral surface 42), and in a sectional view similar to that shown in fig. 3, the sectional surface of each recess is formed in a triangular shape gradually decreasing in width from the outer peripheral surface 41 toward the radially inner side, as shown in fig. 6. The maximum included angle X' between the opposite side surfaces (the surfaces on the left and right sides of the triangle in fig. 6) of the recess in the axial direction of the guide wire is in the range of 5 ° to 25 °. Further preferably, the maximum angle is in the range of 10 ° to 20 °. In an embodiment of the present application, the maximum included angle may be 5 °, 10 °, 15 °,20 °, or 25 °.
In one embodiment of the present invention, the cut pattern may be formed by removing a portion of the material of the body portion 10 by laser cutting as the recess in any of the embodiments described above.
A portion of material may be removed from the body portion 10 in a particular laser cutting pattern by a laser cutting technique to form the recesses in any of the embodiments described previously to achieve different desired mechanical properties. The cutting pattern may be formed to linearly extend in an arc shape along the circumferential direction of the body part 10 as shown in fig. 2. However, the present application is not limited thereto, and for example, the cutting pattern may be formed in a wavy shape, a zigzag shape, a spiral shape, or the like extending in the circumferential direction.
Existing ways of machining, such as micro-sawing or wire EDM, may be limited by the geometry of the kerf, the length that can be cut, the speed of machining, etc., resulting in limited cutting efficiency, application scenarios, etc.
Compared with the existing processing mode, the laser cutting technology can be used for cutting geometric shapes in medical instruments such as guide wires, narrower cutting width and higher cutting efficiency can be achieved, and further, the design of complex cutting patterns which cannot be achieved by the existing processing mode can be achieved, and therefore balance among bending rigidity, torsional rigidity and tensile strength is achieved. And, the laser cutting technique can be used to adjust the direction of laser cutting by adjusting the angle of the laser, thereby achieving the removal of more material near the outer peripheral surface of the guide wire, thereby forming a cut of trapezoidal or triangular cross-section, for example, as described above.
In another embodiment of the application, the recess in any of the embodiments described above may be formed by removing a portion of the material of the body portion 10, for example by etching. And the characteristics of the formed recess may be substantially the same as the recess formed by laser cutting as described above, and will not be described here.
In one embodiment, as shown in fig. 7, an etching mask 51 may be first formed on the outer circumferential surface of the body portion 10, the etching mask 51 having a specific etching pattern (e.g., a stripe-shaped circular arc corresponding to the recess) formed thereon, and then an etchant is applied to the etching mask 51 to etch and thus remove the material of the body portion 50 (e.g., the aforementioned body portion 10) within the etching pattern to form the recess in any of the aforementioned embodiments. Finally, the etching mask 51 is removed.
By the etching process as described above, substantially the same technical effects as those of the laser cutting technique described above can be efficiently achieved.
Further, in addition to the cross-sectional shape of a trapezoid (refer to fig. 8) or a triangle, a cross-section of other shape may be formed by etching.
For example, as shown in fig. 9, the cross-section of the concave portion may be formed in a curved shape on both sides facing each other in the axial direction of the hypotube by using an anisotropic etching process.
Further, for example, since the etching process can realize layered etching, the sectional shape of the recess formed by etching is not limited to the trapezoid, triangle, or shape having a curve described above, but may be formed in an arbitrary curve shape as long as a variation tendency in which the width of the recess decreases from the outer peripheral surface of the body portion to the radially inner side can be ensured.
As an example, referring to fig. 10, for example, the concave portion 11 or 12 may be formed in such a manner that a plurality of rectangular-section layers having widths w1, w2, w3, w4 … … wN (w 1 < w2 < w3 < w4 … … wN) from the inner peripheral surface to the outer peripheral surface, respectively, are formed by N continuous etching processes using the first etching mask, the second etching stamper … …, the N-th etching mask, so that both side surfaces of the concave portion opposite in the axial direction of the hypotube have a stepped shape. At this time, the range of the maximum included angle between the contour lines on both sides connecting the corner points of the steps is in the range of 5 ° to 25 °.
As another example, the shape and depth of the recess, etc. may be controlled by controlling the etching time of the etching process.
According to an embodiment of the present application, as shown in fig. 11, a guidewire of an embodiment of the present application guides an outer catheter (microcatheter) 200, such as that shown in fig. 11, to a desired location within a vessel to release various interventional instruments, such as coils, stents, etc., into place.
In the embodiment of the application, due to the adoption of the tubular hypotube structure, part of materials are removed from the tubular structure in a specific pattern, so that the flexibility of the tubular structure is enhanced, and meanwhile, space is provided for further bending of the tubular structure, so that a smaller bending radius of the guide wire is realized.
Because the guidewire has enhanced flexibility, the approach of the guidewire to the vessel wall can be reduced, thereby reducing friction during delivery. This is particularly advantageous when delivered to intracranial vessels, since the intracranial vessels are not protected by muscle traction, resulting in a more fragile structure, and if the guidewire is less flexible, there is a higher likelihood that the vessel will puncture or straighten and thereby damage the nerve. The guide wire of the application adopts the hypotube, and a part of materials of the hypotube are removed to form the concave part with the cross section in a trapezoid shape or a triangle shape and the like, and the width of the concave part gradually decreases from the outside to the inside, so the flexibility is higher, thereby being capable of conforming to the tortuous anatomical structure of a blood vessel and further reducing the friction force, traction and damage to nerves of the blood vessel.
Further, since the plurality of concave portions in the hypotube are formed to be concave in such a manner as to decrease in width from the outer peripheral surface of the body portion toward the radially inner side, an additional space is provided for adjacent loop portions to be close to each other to further avoid the adjacent loop portions from abutting against each other, thereby realizing a smaller bending radius as compared with the vertically concave portions, so that collision between the loops can be avoided or prevented when the guidewire passes through a blood vessel having an intracranial distal end meandering, so that the bending radius of the guidewire is too large to reach a desired lesion position. Thus, the flexibility is further improved and the tortuous anatomy of the blood vessel is further complied with, thereby further reducing friction, traction and damage to the nerve of the blood vessel.
Further, since the maximum included angle between the opposite side surfaces of the concave portion of the hypotube of the guide wire in the axial direction of the hypotube is in the range of 5 ° to 25 °, the balance of the flexibility, tensile strength, torque transmission and other performances of the guide wire can be ensured, the phenomenon that the guide wire is close to the vascular wall can be reduced, the friction force in the conveying process can be reduced, and at the same time, the pushing force and the torque control force can be smoothly transmitted from the proximal end of the guide wire to the distal end of the guide wire.
The foregoing is merely an optional implementation manner of some of the implementation scenarios of the present application, and it should be noted that, for those skilled in the art, other similar implementation manners based on the technical ideas of the present application are adopted without departing from the technical ideas of the scheme of the present application, and the implementation manner is also within the protection scope of the embodiments of the present application.