GUIDEWIRE FOR OPTICAL SHAPE SENSING

Abstract

A guidewire with a cross section of at least a part of its length, comprising a filling material (PLM), a lumen (LM) arranged inside the filling material (PLM) for accommodating an optical fiber (OF) with optical shape sensing properties. One or more stiffening elements (RD) are arranged inside the first material (PLM), wherein the stiffening element(s) (RD) is formed by a material having a higher axial stiffness than the filling material. A braiding structure (BR) encircles all of: the filling material (PLM), the lumen (LM), and the stiffening element(s) (RD). Such guidewire can be designed with a circular symmetric bending behavior, and is thus suitable as an interventional medical device, e.g. for endovascular procedures, and still it can provide optical shape sensing properties.

Claims

1. An elongated device with a cross section at at least a part of its length, comprising a filling material (PLM) with a first axial stiffness, a lumen (LM) arranged inside the filling material (PLM) for accommodating an optical fiber (OF) with optical shape sensing properties, at least one stiffening element (RD) arranged inside the filling material (PLM) and outside the lumen , the at least one stiffening element (RD) is formed by a material having a second axial stiffness, and wherein the second axial stiffness is higher than the first axial stiffness, and a braiding structure (BR) encircling all of: the filling material (PLM), the lumen (LM), and the at least one stiffening element (RD).

2. Elongated device according to claim 1, wherein the filling material (PLM), the lumen (LM), the stiffening element (RD), and the braiding structure (BR) are configured with respect to material stiffnesses, and relative geometrical position, so as to provide a circular or substantially circular bending behavior of at least a length portion of the elongated device.

3. Elongated device according to claim 1, wherein the at least one stiffening element (RD) tapers in a distal end portion of the device.

4. Elongated device according to claim 1, wherein the braiding structure (BR) has a first braiding angle (BA1) in a proximal portion of the device, which is different from a second braiding angle (BA2)in a distal end portion of the device.

5. Elongated device according to claim 1, whereinan outer diameter of the braiding structure (BR) tapers in a distal end portion of the device.

6. Elongated device according to claim 1, comprising a plurality of separate stiffening elements (RD1, RD2) arranged inside the filling material (PLM).

7. Elongated device according to claim 6, wherein said plurality of separate stiffening elements (RD1, RD2) are arranged equally spaced from each other.

8. Elongated device according to claim 6, comprising at least two straight stiffening elements (RD).

9. Elongated device according to claim 6, wherein said plurality of separate stiffening elements (RD1, RD2) are spiraled around the lumen (LM).

10. Elongated device according to claim 6, comprising two stiffening elements (RD, W) with different cross sectional shape.

11. Elongated device according to claim 6, wherein said plurality of separate stiffening elements (RD1, RD2) are arranged concentric around the lumen (LM).

12. Elongated device according to claim 1, wherein the filling material (PLM) is a polymeric material and wherein the at least one stiffening element (RD) is formed by a material comprising a metal.

13. Elongated device according to claim 1, wherein the elongated device (GW) is a guidewire.

14. An optical shape sensing system comprising an elongated device (GW) according to claim 1, an optical fiber with optical shape sensing properties along at least a part of its length, wherein the optical fiber is arranged for insertion into the lumen of the elongated device (GW) so as to follow a shape of the elongated device (GW), and an optical console system (P, SSC) arranged for interrogating said optical shape sensing properties of the optical fiber, and to accordingly determine a measure of a three-dimensional shape (I) of at least a part of the elongated device (GW).

15. Method of manufacturing an elongated device, the method comprising providing (P_ES) an elongated structure by a filling material formed by a material having a first stiffness, providing (P_STE) at least one stiffening element formed by a material having a second stiffness, and wherein the second stiffness is higher than the first stiffness, providing (P_BR) a braiding structure, forming (F_LM) a lumen inside the elongated structure formed by the filling material, arranging (A_STE) the at least one stiffening element inside the elongated structure and outside the lumen, and encircling (E_BR) all of: the elongated structure, the lumen, and the at least one stiffening element by the braiding structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

[0051] FIG. 1 shows the guidewire with an OSS fiber arranged in a lumen,

[0052] FIG. 2 illustrates an cross sectional sketch of an embodiment,

[0053] FIGS. 3a and 3b illustrates a cross sectional sketch and a longitudinal section of another embodiment, respectively,

[0054] FIG. 4 illustrates a cross sectional view of yet another embodiment,

[0055] FIG. 5a illustrates a longitudinal section of a distal end portion of a guidewire of another embodiment,

[0056] FIG. 5b illustrates a longitudinal section of a proximal portion of the guide wire of the embodiment in FIG. 5a,

[0057] FIG. 6a illustrates a longitudinal section of a distal end portion of a guidewire of another embodiment,

[0058] FIG. 6b illustrates a longitudinal section of a proximal portion of the guide wire of the embodiment in FIG. 6a,

[0059] FIG. 7a illustrates a longitudinal section of a distal end portion of a guidewire of another embodiment,

[0060] FIG. 7b illustrates a longitudinal section of a proximal portion of the guide wire of the embodiment in FIG. 7a,

[0061] FIG. 8a illustrates a longitudinal section of a distal end portion of a guidewire of another embodiment,

[0062] FIG. 8b illustrates a longitudinal section of a proximal portion of the guide wire of the embodiment in FIG. 8a,

[0063] FIG. 9 illustrates basic parts of a system embodiment, and

[0064] FIG. 10 shows steps of a method embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0065] FIG. 1 shows a longitudinal section sketch of an elongated device embodiment in the form of a guidewire. A flexible guidewire structure GWS, to be explained in further details later, has a lumen shaped to provide space for an OSS fiber OF to which light L can be applied for optical interrogation, and OSS to allow reconstruction of the shape if the guidewire.

[0066] FIG. 2 shows a cross sectional sketch of an embodiment in the form of a guidewire. Here, the lumen LM for the OSS fiber is positioned in the center of the guidewire which has an overall circular cross sectional shape. Three rods RD, here shown with circular cross section, are equally spaced from each other. The rods RD serve as stiffening elements and are cast or embedded within a polymeric filling material PLM. A braiding structure BR encircles the cross sectional area which includes the lumen LM, the rods RD and the filling material PLM, i.e. over the entire circumference. A polymer “jacket” PJK serves to cover the braiding structure BR.

[0067] The three stiffening rods RD can be made from any metal or other stiff material, i.e. with an axial stiffness which is higher than the stiffness of the filling material PLM, and will ensure (almost) circular symmetry in bending while providing additional axial stiffness.

[0068] With the braiding structure BR, a torque from proximal to distal of the guidewire can transferred. The braiding wire forming the braiding structure BR can be made of different materials and can have the form of a wire like stainless steel, copper, Kevlar, nylon, or any other type of metal or polymer. In a variant, it is to be understood that even more than three (identical or different) rods can be distributed in the filling material PLM, e.g. 4, 5, 6, or even more separate stiffening elements.

[0069] FIG. 3a shows a cross sectional sketch, and FIG. 3b shows a longitudinal view another guidewire embodiment, which however has the same braiding structure BR, and filling material PLM, and has an overall circular cross section, as in FIG. 2. Here, two stiffening rods RD1, RD2 are counter spiraled around the lumen LM to ensure almost circular symmetry in bending, while providing additional axial stiffness. The counter spiraled stiffening rods RD1, RD2 arranged within the filling material PLM are shown in FIG. 3b. In an example, the stiffening rods RD1, RD2 are spiraled to provide at least 1 spiral revolutions per meter, but can have more spiral revolutions per meter to increase the flexibility and torque response of the guide wire.

[0070] FIG. 4 shows a cross sectional sketch of still another guidewire embodiment which has a similar braiding structure BR, and filling material PLM, and has an overall circular cross section, as in FIG. 2. In FIG. 4, the OSS lumen LM is placed eccentric with a stiffening RD rod with circular cross section, and an additional stiffening element in the form of a wire W with a rectangular cross sectional shape. The rod RD and rectangular wire W will provide axial and bending stiffness where the bending stiffness can be made equal for both main bending directions by a well-chosen design. The braiding structure BR is placed around over the entire circumference, covered e.g. by a polymer “jacket”. The rod RD and/or wire W can be made of any metal or other stiff material.

[0071] The shown elongated device embodiments are in the form of guidewires, since it is appreciated that it is possible to provide OSS fiber properties within a thin guidewire to allow medical applications in the form of e.g. endovascular procedures, and still maintain a high flexibility in combination with a high axial stiffness. However, the structural design may be considered to resemble a microcatheter.

[0072] FIG. 5a shows a longitudinal sectional sketch of a distal end portion of still another guidewire embodiment. FIG. 5b shows a longitudinal sectional sketch of a proximal portion of the embodiment in FIG. 5a. In cross-section, the embodiment in FIGS. 5a and 5b is similar with the embodiment in FIG. 2, i.e. has a central lumen LM, three stiffening elements RD placed 120° from each other about the longitudinal axis, and a filling material PLM in which the stiffening elements RD are embedded. A brading structure BR is placed around over the entire circumference with respect to the longitudinal axis of the device. A polymer “jacket” PJK covers the arrangement.

[0073] In this embodiment, the stiffening elements RD extend over the entire length of the guidewire or end proximal of the distal end, in this case preferably maximally about 100 mm proximal of the distal end.

[0074] According to FIG. 5b, the stiffening elements RD which are configured as wires or rods, have a constant diameter in the proximal portion of the guidewire. In the distal end portion shown in FIG. 5a, the stiffening elements RD have a tapering section TS, in which the stiffening elements RD taper over a length of preferably at least 250 mm, or less if needed.

[0075] In a preferred example, the outer diameters of the stiffening elements RD are about 0.10 mm in the proximal portion according to FIG. 5b, while the outer diameters of the stiffening elements RD taper in the tapering section TS from 0.10 mm to about 0.05 mm. The stiffening elements RD are preferably made of stainless steel or nitinol, but can be any high strength metal and/or alloy like MP35N. The braiding structure BR has a braiding angle BA which is constant over the entire length of the braiding structure BR. The braiding structure BR extends til the distal end of the guidewire in a configuration where the stiffening elements RD end proximal of the distal end. Vice versa, in case the stiffening elements RD end at the distal end of the guidewire, the braiding structure BR ends about maximally 100 mm proximal of the distal end.

[0076] The braiding angle BA is in a range from about 25° to about 70°. The lower the braiding angle is, the stiffer is the braiding structure BR and, thus, the guidewire, while larger braiding angles BA lead to more flexible guidewires. In a preferred example, the braiding angle BA is about 55°.

[0077] The braiding structure BA is formed by braiding wires which are rectangular or circular in cross-section. In a preferred example, the braiding wires have a cross-sectional size of 25×125 micron when being rectangular, or 50 micron in diameter when being circular in cross-section.

[0078] In the embodiment shown, the maximum outer diameter of the total guidewire is about 0.98 mm, but can also be thinner, such as about 0.89 mm.

[0079] FIG. 6a shows a longitudinal sectional sketch of a distal end portion of still another embodiment of a guidewire, and FIG. 6b shows a longitudinal sectional sketch of a proximal portion of the same guidewire. This embodiment is similar to the embodiment shown in FIGS. 5a and 5b with the difference that the stiffening elements RD are straight over their entire length, i.e. do not taper in the distal end portion of the device.

[0080] In a preferred example, the outer diameter of the stiffening elements RD is constant and about maximally 0.10 mm, and can be smaller if preferred.

[0081] FIG. 7a shows a longitudinal sectional sketch of a distal end portion of a guidewire according to a further embodiment, and FIG. 7b shows a longitudinal sectional sketch of the proximal portion of this guidewire.

[0082] This embodiment is similar to the embodiment shown in FIGS. 5a and 5b, with the difference that the braiding angle of the braiding structure BR is different in the proximal portion of the guidewire (FIG. 7b) than in the distal end portion of the guidewire (FIG. 7a). In particular, the braiding structure BR has a first braiding angle BA1 in the proximal portion, and a second braiding angle BA2 in the distal end portion of the guidewire. The braiding structure BR can be made such that there is a continuous transition from the braiding angle BA1 to the second braiding angle BA2 along the length of the braiding structure BR, or there is a position P along the length of the braiding structure BR at which the braiding angle discontinuously changes from the braiding angle BA1 to the braiding angle BA2. The position P can coincide with the proximal end of the tapering sections TS of the stiffening elements RD.

[0083] In particular, the braiding angle BA2 is larger than the braiding angle BA1. In a preferred example, the braiding angle BA1 is in a range from about 20° to about 40°, while the braiding angle BA2 is in a range from about 40° to about 60°.

[0084] A varying braiding angle over the length of the braiding structure and, thus, the guidewire, allows for a more optimal distribution of mechanical properties over the length of the braiding structure and, thus, the guidewire.

[0085] FIG. 8a shows a longitudinal sectional sketch of a distal end portion of a guidewire according to a further embodiment, and FIG. 8b shows a longitudinal section sketch of a proximal portion of this guidewire.

[0086] This embodiment is similar to the embodiment shown in FIGS. 5a and 5b with the difference that the braiding structure BR tapers in the distal end portion of the guidewire. This means, since the braiding structure BR has a tubular shape, that the outer diameter of the braiding structure BR decreases towards the distal end in the distal end portion of the guidewire. In particular, the tapering profile of the braiding structure BR can follow the tapering profile of the stiffening elements RD. Such a configuration increases the flexibility of the guidewire at the distal end thereof.

[0087] It is to be understood that features of the embodiments according to FIGS. 5a, 5b to 8a, 8b can be combined with one another. For example, in the embodiment according to FIGS. 8a and 8b, the braiding structure BR can have a varying braiding angle between the proximal portion and the distal end portion as described with respect to FIGS. 7a and 7b. Other combinations are also conceivable to a person skilled in the art.

[0088] FIG. 9 illustrates basic parts of a system embodiment where a medical guidewire GW according to the invention, which has an OSS fiber arranged inside. A processor P is arranged to control an optical shape sensing console SSC which is connected to the OSS fiber arranged inside the guidewire GW, and arranged to optically interrogate strain sensing optical elements in the OSS fiber. Accordingly, an image I of a three-dimensional shape of at least a part of the OSS fiber can be reconstructed, and thereby also of a three-dimensional shape of at least a part of the guidewire GW, and thus also a catheter in which the guidewire GW may be inserted. E.g. such 3D image I can be displayed as an image I on a monitor in real time.

[0089] Especially, the system may form part of an interventional medical examination system which allows the user to navigate an interventional medical instrument inside during an interventional procedure.

[0090] FIG. 10 shows steps of an embodiment of a method of manufacturing a guidewire. The method comprises providing P_ES an elongated structure by a filling material formed by a material having a first axial stiffness, providing P_STE at least one stiffening element formed by a material having a second stiffness, and wherein the second stiffness is higher than the first stiffness, and providing P_BR a braiding structure. A lumen is formed F_LM inside the elongated structure formed by the first material, and the at least one stiffening element is arranged A_STE inside the elongated structure, such as cast or in other ways embedded therein. The braiding structure is then encircled E_BR around all of: the elongated structure, the lumen, and the at least one stiffening element. Further, the method may comprise the step of arranging an OSS fiber inside the lumen.

[0091] It is to be understood, that the steps may be performed in a different order than mentioned above, such as known by the person skilled within manufacturing of guidewires and/or catheters.

[0092] To sum up the invention provides a guidewire with a cross section of at least a part of its length, comprising a filling material PLM, a lumen LM arranged inside the filling material PLM for accommodating an optical fiber OF with optical shape sensing properties. One or more stiffening elements RD are arranged inside the first material PLM, wherein the stiffening element(s) RD is formed by a material having a higher axial stiffness than the filling material. A braiding structure BR encircles all of: the filling material PLM, the lumen LM, and the stiffening element(s) RD. Such guidewire can be designed with a circular symmetric bending behavior, and is thus suitable as an interventional medical device, e.g. for endovascular procedures, and still it can provide optical shape sensing properties.

[0093] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.