Obturator with rigid distal cannula engagement region

Abstract

Disclosed herein are obturators that prevent or reduce gaps between the obturator and the catheter into which it is inserted when the combined obturator and catheter are folded. For example, described herein are obturators that include a distal cannula engagement region that is configured to match the stiffness of the distal end region of the catheter into which it is inserted. Also described herein are obturators that include a distal cannula engagement region that has a stiffness greater than that of the surrounding portions of the obturator.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 292,415, filed December 21, 2021, and entitled "OBTURATOR WITH STIFF DISTAL CANNULA ENGAGEMENT REGION," the entirety of which is incorporated herein by reference.

[0002] Incorporation by Reference

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0003]

[0003] This application relates to the field of obturators for use in medical procedures. [Background technology]

[0004]

[0004] Obturators are medical devices that can be used to center and guide a catheter as it is guided along a guidewire to the anatomical structure of interest. For example, obturators can be used as part of a trocar assembly (e.g., including a cannula and an obturator) for laparoscopic, endoscopic, or arthroscopic surgery, or virtually any surgical procedure in which a cannulated member (e.g., a cannula) is inserted into the body. Obturators typically extend beyond the cannula into which they are inserted and may have a tapered or even pointed distal end region that can aid in insertion into the body. In some cases, obturators can be solid, or they can be hollow and / or include one or more elongated lumens that extend therethrough.

[0005]

[0005] It has long been recognized that in some cases, a gap can form between the cannula and the exterior surface of the obturator, especially when navigating tortuous portions of the anatomy. The presence of a gap between the catheter and obturator is known as a tip gap. When this gap is the result of the catheter and obturator being used in curved anatomy, the gap can become pronounced, resulting in a condition known as a fishmouth. These types of gaps, when combined together, are simply referred to as one or more "gaps."

[0006]

[0006] Gaps can be a patient safety concern and / or affect the functionality and trackability of the catheter through the vessel. Gaps can result in pinching of tissue, which can cause patient trauma and procedural complications. Gaps can get caught in branching vessels and impede advancement through the anatomy. There is a need for a device or system to minimize gaps between the catheter and the obturator. Summary of the Invention [Means for solving the problem]

[0007]

[0007] Described herein are methods and devices (e.g., systems, instruments including an obturator) that can provide an obturator that prevents a gap (fishmouth) between the obturator and a cannula. In particular, described herein are methods and devices in which at least a distal end region of the obturator that is configured to align with a distal end region of a cannula (e.g., including a distal end opening of the cannula), referred to herein as a distal cannula-engaging region of the obturator, has a stiffness that is greater than the stiffness of a region of the obturator immediately proximal and / or distal to the distal cannula-engaging region.

[0008]

[0008] Gaps are typically created when there is a large difference in bending stiffness between the obturator and the distal end region of the cannula. Gaps are exacerbated when the distal tip of the distal end region is made of a material with a lower durometer hardness and stiffness, and the region just proximal to the distal tip is stiffer than the distal tip. The distal tip is often made to have a low durometer hardness and stiffness so as not to disintegrate or damage the anatomical structures during the procedure. The region just proximal to the distal tip is typically stiffer than the distal tip because the body of the cannula must retain its shape and withstand pushing, pulling, twisting, and pinching loads. Also, the region just proximal to the distal tip is typically stiffer than the distal tip because reinforcing elements such as wires, braids, and smooth liners terminate in this region, and these terminations require reinforcement such as welds, adhesives, and heat sinks to prevent the reinforcing elements from becoming dislodged. When the distal tip is less stiff than the region just proximal to the distal tip, the bending load from the obturator is applied to the distal tip rather than folding the stiffer proximal region, deforming the soft distal tip and causing it to ovalize and create gaps. As used herein, the distal end region of a catheter may refer to the generally stiffer distal end region of the catheter (e.g., the region just proximal to the distal tip).

[0009]

[0009] The stiffness of a catheter and / or obturator may be measured in terms of flexural modulus. Generally, flexural modulus is a measure of the bending stress of a material versus elongation under load. It provides an elastic measurement of the stiffness of a material for a given test sample and geometry. For example, the stiffness of a polymer tube may be determined by the inherent stiffness (elastic modulus) of the material and the cross-sectional design of the catheter. Varying the dimensions of the cross-section may have a significant effect on stiffness. As described herein, flexural modulus may be utilized when describing the stiffness ratio of a catheter or obturator. Flexural modulus is measured in Pascals (Pa or N / m 2 or m -1 kg s -2), and in practice the units are megapascals (MPa or N / mm 2 ) or Gigapascals (GPa or kN / mm 2 ).

[0010] In some examples, the stiffness of the distal cannula engaging region of the obturator can be greater than a percentage of the stiffness of the region of the obturator immediately adjacent to the distal cannula engaging region. For example, the stiffness of the distal cannula engaging region of the obturator can be 10% or more (e.g., 12.5% ​​or more, 15% or more, 17.5% or more, 20% or more, 22.5% or more, 25% or more, 27.5% or more, 30% or more, 40% or more, 45% or more, 50% or more, etc.) of the stiffness of the region of the obturator immediately adjacent to the distal cannula engaging region either proximally and / or distally.

[0011]

[0011] Similarly, described herein are obturators having a distal end region (distal cannula engaging region) that matches the stiffness of a cannula, particularly the distal end region of the cannula. Thus, any of the obturators described herein may have an obturator distal cannula engaging region that has a stiffness that matches the stiffness of the distal end region of the cannula into which the obturator is inserted. The stiffness-matched distal cannula engaging region of the obturator may be matched to the stiffness of the distal end region of the cannula within ± a certain percentage of the stiffness of the distal end region of the cannula. For example, the stiffness may be matched within ±20%, ±15%, ±14%, ±13%, ±12%, ±11%, ±10%, ±9%, ±8%, ±7%, ±6%, ±5%, ±4%, ±3%, ±2%, ±1%, etc. The region of the obturator distal or proximal to the stiffness-matched distal cannula engagement region of the obturator may be significantly more or less stiff than the distal end region of the cannula. In some instances, the entire length of the obturator may be stiffness-matched to the distal end region of the cannula, or only the portion of the obturator that is configured to align with the distal end region of the cannula may be stiffness-matched.

[0012]

[0012] When matching the stiffness of the obturator distal end region (e.g., the distal cannula engaging region) to the stiffness of the cannula, the stiffness may be matched to the stiffness of a region just proximal to the distal tip which is typically stiffer than the distal tip. Generally, the stiffness of the obturator distal end region (e.g., the stiffest region in the distal x mm (e.g., the distal 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.) of the cannula distal end region.

[0013]

[0013] The obturators described herein may have a distal cannula engaging region that has a stiffness greater than the stiffness of the region of the obturator immediately proximal and / or distal to the distal cannula engaging region, and may also have a stiffness of the distal cannula engaging region that is matched to the stiffness of the distal end region of the cannula (e.g., within ± a certain percentage of the stiffness of the distal end region of the cannula).

[0014]

[0014] Generally, the distal cannula engagement region of the obturator may extend between 1 mm and 40 mm along the length of the distal end region of the obturator. For example, the distal cannula engagement region may extend a distance of 2 mm or more (e.g., 3 mm or more, 4 mm or more, 5 mm or more, 6 mm or more, 7 mm or more, 8 mm or more, 9 mm or more, 10 mm or more, 11 mm or more, 12 mm or more, 13 mm or more, 14 mm or more, 15 mm or more, between 2 and 40 mm, between 2 and 35 mm, between 2 and 30 mm, between 2 and 25 mm, between 2 and 20 mm, between 2 and 15 mm, between 2 and 10 mm, between 2 and 5 mm, etc.). The majority of the length of the obturator, including regions proximal to the distal cannula engagement region and / or regions distal to the distal cannula engagement region, may have a different stiffness than the distal cannula engagement region (e.g., may be less stiff than the distal cannula engagement region of the cannula).

[0015]

[0015] The distal cannula engagement region of the obturator may be made more rigid (or in some instances may be made to match the rigidity of the distal end region of the cannula) by including an insert within the body of the obturator at the distal cannula engagement region, a region configured to be aligned with the distal end region of the cannula during use (e.g., during advancement through the body). For example, the distal cannula engagement region of the obturator may include an inner tubular member having a greater rigidity than other regions of the obturator (and / or which may match the rigidity of the distal end region of the cannula into which the obturator is to be inserted).

[0016]

[0016] In some examples, the distal cannula engagement region of the obturator is formed of a material having a stiffness (flexural modulus) greater than the stiffness of other regions of the obturator (or in some examples, having a stiffness that matches the stiffness of the distal end region of the cannula, e.g., within ± a certain percentage of the stiffness of the distal end region of the cannula).

[0017]

[0017] The distal cannula engagement region (or in some variations, an insert within the distal cannula engagement region) may be formed of a harder plastic material so that it does not bend or flex as much as the tapered distal trip region of the obturator and / or the adjacent proximal region of the obturator. The bulk of the obturator may be elastomeric so as to bend more easily. Elastomers may be measured in hardness (durometer hardness), although there is an approximate relationship between durometer hardness and modulus of elasticity for elastomers. See, for example, Dow Coming White Paper, "Can You Estimate Modulus From Durometer Hardness for Silicones?" (incorporated herein by reference in its entirety), at https: / / www.dow.eom / content / dam / dcc / documents / en-us / tech-art / l 1 / 11-37 / 1 l-3716-01-durometer-hardness-for-silicones.pdf.

[0018]

[0018] For example, the present specification describes a system comprising a catheter having a distal end region having a first stiffness, and an obturator having a distal cannula engaging region having a stiffness matched to the first stiffness, where the stiffness of the distal cannula engaging region is different from the stiffness of a tapered region distal to the distal cannula engaging region and different from the stiffness of a region of the obturator proximally adjacent to the distal cannula engaging region, wherein the obturator and catheter are configured to proximally engage one another such that the distal cannula engaging region is aligned with the distal end region of the catheter to form a combined structure to prevent the formation of gaps between the obturator and the catheter when the combined structure is bent or curved.

[0019]

[0019] The distal cannula engaging region may include a stiffening component. The stiffening component may include a tubular member within the distal cannula engaging region. The stiffening component may include a material having a higher stiffness than a material forming a tapered region distal to the distal cannula engaging region and / or a region of the obturator proximally adjacent thereto. In some examples, the stiffening component includes an internal skeleton.

[0020]

[0020] The distal cannula engaging region may include a length that is between 1 mm and 40 mm. For example, the distal cannula engaging region may include a length that is greater than 5 mm.

[0021]

[0021] The obturator may include an elongated guidewire channel that extends down the length of the obturator.

[0022] In some examples, the stiffness matched to the first stiffness is within ±5% of the first stiffness. The distal cannula engaging region may include a stiffening insert within the distal cannula engaging region.

[0023]

[0023] For example, the obturator may include an elongate body including a tapered distal end and including a first material, and a distal cannula engaging region of the elongate body, the distal cannula engaging region including an insert, the distal cannula engaging region proximal to the tapered distal end of the elongate body and distally adjacent to a second region of the elongate body, the insert including a material having a stiffness greater than the stiffness of the first material such that the stiffness of the distal cannula engaging region is greater than the stiffness of the tapered distal end and the second region.

[0024]

[0024] The obturator may include an obturator lumen extending through the elongate body. The insert may include an insert lumen coaxial with the obturator lumen. The insert may have a length between about 1 mm and 20 mm. The insert may have a stiffness between about 0.2 and about 2.5 GPa. In some examples, the stiffness of the insert is greater than twice the stiffness of the first material. The insert may be coaxial with the obturator. The obturator may comprise an obturator or a dilator.

[0025]

[0025] The insert may have an outer diameter smaller than the outer diameter of the distal cannula engagement region.

[0026]

[0026] Any of the obturators described herein may include a stop at the proximal end region of the obturator configured to secure the distal cannula engagement region of the obturator in alignment with the distal end region of the catheter into which the obturator is inserted.

[0027]

[0027] The novel features of the invention are set forth with particularity in the following claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings. [Brief description of the drawings]

[0028] [Figure 1A]

[0028] FIG. 1 shows an example of an obturator including a distal cannula engagement region. [Figure 1B]

[0029] FIG. 1 illustrates an example of a cannula. [Figure 1C]

[0030] 1B such that the distal cannula engagement region is engaged with the distal end region of the cannula. FIG. [Figure 2A]

[0031] FIG. 13 is a diagram showing an example of a gap (eg, a fish mouth) that occurs between an obturator and a catheter. [Figure 2B] FIG. 13 is a diagram showing an example of a gap (eg, a fish mouth) that occurs between an obturator and a catheter. [Diagram 3]

[0032] 13A-13D show an embodiment of an obturator including a stiffening component in the distal cannula engagement region. [Figure 4]

[0033] FIG. 4 shows a comparison of an obturator and catheter system with and without a stiffening component as shown in FIG. 3. [Figure 5A]

[0034] FIG. 13 shows an obturator having a distal cannula engagement region that is matched in stiffness to the distal end region of the catheter into which it is inserted. [Figure 5B]

[0035] 13A-13C show an example of a proximal end of an obturator including a distal cannula engagement region. [Figure 6A]

[0036] FIG. 1 illustrates an example of an obturator including a distal cannula engagement region having two stiffness-matched regions arranged in a line having different stiffnesses that can be used with catheters having different stiffnesses at their distal end regions, the obturator being in a first position with the first stiffness-matched region aligned with the distal end region of a first catheter (having equal or nearly equal stiffness). [Figure 6B] FIG. 13 illustrates an example of an obturator including a distal cannula engagement region having two rigidity-matched regions arranged in a line having different rigidity that may be used with a catheter having a different rigidity at its distal end region, the obturator being in a second position with the second rigidity-matched region aligned with the distal end region of a second catheter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029]

[0037] Generally described herein are devices (instruments and systems including obturators) and methods for their use that prevent or reduce a "fishmouth" or gap between an obturator and a catheter in which the obturator is positioned when the two are advanced through a curved body lumen. These devices may include an obturator having a distal cannula-engaging region that is configured to have a stiffness (flexural modulus) that is approximately the same as the stiffness of a distal end region of the cannula in which the obturator is positioned. In some examples, the obturator has a distal cannula-engaging region that is stiffer than other adjacent regions of the obturator. For example, the obturator may include an insert positioned within the distal cannula-engaging region. For example, the insert may be positioned proximal to a tapered distal end of the elongated body of the obturator. The insert may include a material that has a greater stiffness than the stiffness of adjacent regions of the obturator that may be formed of a less stiff material.

[0030]

[0038] For example, Figure 1A shows one example of an obturator 102. The obturator has an elongate body 115 and a tapered distal end 107. The obturators described herein also include a distal cannula engagement region 103 proximal from the tapered distal end and configured to engage a distal end region of a cannula (see, e.g., Figure 1C), such that the distal cannula engagement region 103 can span a distal end opening of the distal end region.

[0031]

[0039] The obturator can be solid or hollow, hi some instances, the obturator includes a lumen extending through the length of the obturator.

[0032]

[0040] In FIG. 1A, the distal cannula engagement region 103 can be stiffer than the adjacent distal region (which may include the tapered distal end 107) and the proximal body region 109, 109' of the elongate member 115. In some cases, the distal cannula re-engagement region is formed of a stiffer material than the adjacent regions. In some cases, the distal cannula region includes an internal structure or insert (e.g., a support, a framework, a tube, etc.) that increases the stiffness of the distal cannula re-engagement region. The outer diameter of the obturator can be the same all along the obturator to the tapered distal end 107. The outer diameter of the obturator can be generally smaller than the inner diameter of the cannula into which the obturator is to be inserted. The insert can be the full diameter or a portion of the diameter (as described below with reference to FIG. 3).

[0033]

[0041] The obturator may be used with a cannula 104, such as the cannula shown in FIG. 1B. The cannula includes a distal end region 105 that includes a distal end opening 153. Any suitable cannula may be used and configured to engage the obturator such that the obturator and cannula engage one another with the distal cannula engagement region 103 aligned with the distal end region 105 of the catheter, as shown in FIG. 1C. In this example, the distal cannula engagement region extends slightly from the distal end opening 153 of the catheter. In some examples, the distal cannula engagement region is configured to align with the distal end opening. The cannula and obturator may be configured to engage one another, for example, at the proximal ends of the cannula and obturator such that the obturator is gripped in alignment with the distal end region, as shown in FIG. 1C.

[0034]

[0042] The distal cannula engaging region (and thus the stiffness matching or stiffer region) may extend for any suitable length of the obturator, for example between 1 mm and 50 mm (e.g., between 1 mm and 40 mm, between 2 mm and 40 mm, between 1 mm and 35 mm, between 2 mm and 35 mm, between 1 mm and 30 mm, between 2 mm and 30 mm, between 1 mm and 25 mm, between 2 mm and 25 mm, etc.). Similarly, the distal end region of the catheter may extend for any suitable length of the catheter, typically reflecting the stiffness of the distal end. The distal end region of the catheter may be shorter than the distal cannula engaging region. For example, the distal end region of the catheter can be between 1 mm and 50 mm, between 1 mm and 45 mm, between 1 mm and 40 mm, between 1 mm and 35 mm, between 1 mm and 30 mm, between 1 mm and 25 mm, between 1 mm and 20 mm, between 1 mm and 15 mm, between 1 mm and 10 mm, between 1 mm and 9 mm, between 1 mm and 8 mm, between 1 mm and 7 mm, between 1 mm and 6 mm, between 1 mm and 5 mm, between 1 mm and 4 mm, between 1 mm and 3 mm, between 1 mm and 2 mm, etc.

[0035]

[0043] 2A and 2B, an obturator 102 is shown positioned within a catheter 104. A deflected (e.g., bent) obturator tip 106 is shown, illustrating a gap 108 between the obturator tip 106 and the catheter. The gap 108 is clearly shown in the enlarged view of FIG. 2B. Thus, when an obturator such as that shown in FIGS. 2A-2B is advanced over a tortuous path, the distal end openings of the obturator and catheter distal end region may separate, creating a gap that can snag or tear the body wall.

[0036]

[0044] Gaps such as those shown in Figures 2A and 2B can be exacerbated when there is a stiffness mismatch between the parts. Catheters are often constructed to be very flexible, especially in the distal end region of the catheter, and may be somewhat more flexible than the obturator. Catheter tips can vary in stiffness, including plastic catheter tips (which are relatively stiff) and elastomeric tips (which are relatively soft, flexible, and easily deformed). Catheter tips are thin-walled structures, which may allow them to be easily flexed.

[0037]

[0045] The obturator may be a solid body (or may include a narrow channel for a guidewire, for example) and may have a particular stiffness as a result of its geometry. The obturator tip may be very flexible at its distal most tapered point so that it easily tracks over the guidewire. However, proximal to this distal most point, the obturator tip may widen in the proximal portion of a generally constant diameter section where the geometry creates a more rigid body. In some instances, the obturator may vary in diameter to minimize potential tip clearance distance.

[0038]

[0046] Stiffness mismatch may include cases where the tip of the catheter is softer and / or more flexible than the catheter body and the obturator has a flexible distal end. Increasing the flexibility and / or softness of one part may allow that part to deflect more under the same applied force than a stiffer and / or more rigid part. This difference in the amount of deflection may lead to gaps.

[0039]

[0047] In some embodiments, the obturator can be more flexible than the catheter.In some embodiments, the catheter can be more flexible than the obturator.

[0040]

[0048] Disclosed herein are embodiments of obturators that include a relatively stiff distal cannula engagement region of the obturator (e.g., possibly including a stiffening insert) proximal to the axial location of the contact point between the catheter tip and the obturator. The distal cannula engagement region may be configured to substantially match the stiffness of the distal end region of the cannula 104 into which the obturator 102 is inserted. More closely matching the stiffness or flexibility of the catheter tip and the obturator can help minimize gaps.

[0041]

[0049] 3 shows one embodiment of an obturator 200 comprising a distal cannula engaging region 103 that includes an internal stiffening component 202. The obturator 200 is shown positioned within a catheter 204. The distal end 206 of the catheter can be aligned with the distal cannula engaging region 203 (and, in this example, the distal end 208 of the stiffening component 202). In this example, both the obturator and stiffening component include holes or lumens 210 that allow for the passage of a guidewire.

[0042]

[0050] The inlay 202 shown in FIG. 3 is one example of a stiffening component. The insert may have an outer diameter that is a portion of the diameter of the distal cannula engagement region, or it can be the full diameter of the distal cannula engagement region. The length of the insert may be the full length of the distal cannula engagement region, or the length of the insert may be a portion of the distal cannula engagement region. For example, the length may be between about 2 mm and about 20 mm, between about 2 mm and about 17.5 mm, between about 2 mm and about 15 mm, between about 2 mm and about 12.5 mm, between about 2 mm and about 10 mm, etc. In some examples, multiple inserts may be included in the distal cannula engagement region. The insert may be formed of a stiffer material, such as an elastomer or plastic having a higher durometer material, for example, a Shore A durometer hardness of between about 80-110 (e.g., Shore A 80, 85, 90, 95, 100, 105, etc.), or a Shore D durometer hardness of between about 20-100 (e.g., Shore D 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, etc., or any subdivision therein). In some examples, the insert may have a modulus of elasticity of 0.2 GPa or greater. Generally, as shown in FIG. 3, the distal end region of the cannula may have two (or more) sections. For example, the distal end region may include the distal tip 206 and a bond region just proximal to and joining the distal tip, which may be of a lower durometer (e.g., softer) material relative to the remainder of the cannula.

[0043]

[0051] The distal cannula engagement region, and in some examples the stiffening component, can have a variety of different diameters, lengths, and can be made of a variety of different materials. In some embodiments, the insert can have a length of about 2 mm to 40 mm (e.g., between about 2 mm and 30 mm, between about 2 mm and 25 mm, between about 2 mm and 20 mm, between about 2 mm and 15 mm, between about 2 mm and 10 mm, between about 2 mm and 8 mm, etc.).

[0044]

[0052] In some embodiments, the stiffening component can include a cylindrical shape. Other configurations (e.g., rectangular, tubular, etc.) are also possible. In some examples, the stiffening component can be a mesh material. In some examples, the distal cannula engaging region can be formed of a stiffer material, including a stiffer polymeric material. In some examples, the distal cannula engaging region can include a support or scaffolding material within the distal cannula engaging region.

[0045]

[0053] The dimensions of the stiffening component can be selected based on the desired stiffness of the component. The desired stiffness can be based on stiffness matching between the catheter and the obturator. As noted above, in any of these examples, the stiffness of the distal cannula engagement region can be matched to the stiffness of the distal end region of the cannula. For example, the stiffness of the distal cannula engagement region can be within ± a certain percentage of the stiffness of the distal end region of the catheter. For example, the stiffness of the distal cannula engagement region can be matched to within ± 20%, ± 15%, ± 14%, ± 13%, ± 12%, ± 11%, ± 10%, ± 9%, ± 8%, ± 7%, ± 6%, ± 5%, ± 4%, ± 3%, ± 2%, ± 1%, etc. of the distal end region of the cannula. In variations that include a stiffening component, the stiffness of the obturator at the distal cannula engagement region can be a combination of the stiffness of the stiffening component and the surrounding obturator material and structure. The stiffening components may be axially aligned with the device body, or may favor one side if the intended curvature is known.

[0046]

[0054] Generally, the obturator may be formed of a rigid material such as a plastic (e.g., polycarbonate) or a high durometer elastomer (>Shore A 100). Examples of these materials may include, but are not limited to, ABS (acrylonitrile butadiene styrene), ASA (acrylonitrile styrene acrylate), ETFE (ethylene tetrafluoroethylene), LDPE (low density polyethylene), PET (polyethylene terephthalate), and the like.

[0047]

[0055] The distal cannula engagement region can be formed in any suitable manner and can include adding stiffening components. For example, the distal cannula engagement region can be formed by overmolding a soft material onto a stiff material, butt-connecting a stiff material between two softer materials, adding a ring of stiff material to the outside of a softer material, and injecting a different material (e.g., a UV-cured adhesive) into a void in the softer body. The subject device can be another catheter instead of an obturator.

[0048]

[0056] In any of the devices described herein, a closer match in stiffness between the catheter and obturator at the point of potential gaps can allow for a softer catheter tip, thereby minimizing trauma to the patient, and a closer match in stiffness can help minimize gaps, resulting in many clinical benefits including reduced procedural complications.

[0049]

[0057] FIG. 4 shows a comparison of the tip clearance present in systems with and without a stiffening component (e.g., with and without a stiffening component matched to the stiffness of the distal cannula engagement region and the distal end of the catheter). In this example, the obturator is similar to that shown in FIG. 3 including a stiffening component. Point 302 represents a system without a stiffening component. Data point 304 represents a system with a stiffening component having a length of 5.84 mm. Data point 306 represents a system with a stiffening component having a length of 7.62 mm. As shown by this data, the clearance was approximately 40% higher for the system without the insert.

[0050]

[0058] 5A and 5B show one example of an obturator being inserted into a catheter such that the distal cannula engagement region 103 of the obturator 200 is aligned with the distal end region of the catheter 204. The stiffness of the distal cannula engagement region 103 is matched to the stiffness of the distal end region 105 of the catheter. FIG. 5B shows the obturator 200 and the proximal end of the catheter 204, showing the two engaged to one another at the proximal end such that the distal cannula engagement region of the obturator is aligned with the distal end region of the cannula (or in some examples, the distal cannula engagement region extends slightly beyond (and extends beyond) the distal end region of the catheter). In this example, a stop 518 at the obturator proximal end region may engage the proximal end region of the catheter.

[0051]

[0059] The distal cannula engagement region may be longer than the distal end region of the catheter, as shown in Figure 5 A. The length of the cannula and the length of the obturator may be selected such that the stop engages the proximal end of the cannula when the distal cannula engagement region of the obturator is aligned with the distal end region, as described above.

[0052]

[0060] In some examples, such as those shown in Figures 6A-6B, multiple longitudinally separated distal cannula engagement regions may be included that allow the same obturator to be used with different catheters having different stiffnesses at the distal end. For example, in Figure 6A, obturator 200 includes a first distal cannula engagement region and a second distal cannula engagement region adjacent to one another. The first distal cannula engagement region and the second distal cannula engagement region may be separated from one another by a spacer distance (e.g., between 0.1 mm and 20 mm, between 0.1 mm and 10 mm, etc.). In Figure 6A, the first distal cannula engagement region is aligned with the distal end region 105 of the first cannula 204. The second distal cannula engagement region 103' is shown drawn proximally into the first cannula. In FIG. 6B, the same obturator 200 is shown engaged with a second cannula such that the second distal cannula engagement region of the obturator is aligned with the distal end region 105' of the second cannula 204'.

[0053]

[0061] Throughout this description, the term obturator may apply to both obturators and dilators.

[0054]

[0062] In this specification, when a feature or element is referred to as being "on" another feature or element, it can be directly on the other feature or element, or there may be intervening features and / or elements. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features and / or elements. It will also be understood that when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it can be directly connected, attached, or coupled to the other feature or element, or there may be intervening features or elements. In contrast, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements. Although described or illustrated with reference to one embodiment, the features and elements so described or illustrated may be applicable to other embodiments. Those skilled in the art will also recognize that a reference to a structure or feature being disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0055]

[0063] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. For example, as used herein, the singular forms "a" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the term "comprising" as used in this specification specifies the presence of stated features, steps, operations, elements, and / or components, but does not exclude the presence and addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0056]

[0064] Spatial relative terms such as "below," "belower," "lower," "above," and "upper" may be used herein for ease of description to describe the relationship of one element or feature shown in the drawings to another element or feature. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the drawings. For example, if the device in the drawings were inverted, an element described as being "below" or "below" the other element or feature would become "above" the other element or feature. In this manner, the exemplary term "below" can encompass both an above and below orientation. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatial relative descriptors used herein will be interpreted accordingly. Similarly, terms such as "upward," "downward," "vertical," and "parallel" are used for descriptive purposes only, unless expressly indicated otherwise.

[0057]

[0065] In this specification, the terms "first" and "second" may be used to describe various features / elements (including steps), but these features / elements should not be limited by these terms unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another. In this manner, a first feature / element discussed below may be referred to as a second feature / element, and similarly, a second feature / element discussed below may be referred to as a first feature / element, without departing from the teachings of the present invention.

[0058]

[0066] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprises" and variations thereof mean that various components can be employed in conjunction with one another in methods and articles (e.g., apparatus and composites that include methods). For example, it will be understood that the term "comprises" implies the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[0059]

[0067] As used herein in the specification and claims, including those used in the examples, all numbers, unless expressly specified otherwise, can be read as if they are prefaced by the words "about" or "approximately" even if the words do not explicitly appear. The phrases "about" or "approximately" can be used when describing a size and / or location to indicate that the stated value and / or location is within a reasonably expected range of values ​​and / or locations. For example, a numerical value can have a value that is ±0.1% of the stated value (or range of values), ±1% of the stated value (or range of values), ±2% of the stated value (or range of values), ±5% of the stated value (or range of values), ±10% of the stated value (or range of values), etc. Any numerical value given herein should be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value "10" is disclosed, "about 10" is also disclosed. Any numerical range given herein is intended to include all subranges incorporated therein. It is also understood that when a value is disclosed, "less than or equal to" that value, "more than or equal to" that value, and possible ranges between values ​​are also disclosed, as will be properly understood by those skilled in the art. For example, if a value "X" is disclosed, "less than or equal to" and "more than or equal to X" (e.g., X is a number) are also disclosed. It is also understood that throughout this application, data is given in several different formats, and this data represents end and starting points, and ranges for any combination of data points. For example, if a specific data point "10" and a specific data point "15" are disclosed, it is understood that greater than 10 and 15, greater than or equal to 10 and 15, less than 10 and 15, less than or equal to 10 and 15, and equal to 10 and 15, and between 10 and 15 are considered to be disclosed. It is also understood that each unit between two specific units is also disclosed. For example, if 10 and 15 are disclosed, 11, 12, 13, and 14 are also disclosed.

[0060]

[0068] Although various exemplary embodiments have been described above, any of a number of modifications may be made to the various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which the various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments, one or more method steps may be skipped entirely. Optional features of the various device and system embodiments may be included in some embodiments and not in others. Thus, the preceding description has been provided primarily for illustrative purposes and should not be construed as limiting the scope of the invention as described in the claims.

[0061]

[0069] The examples and figures contained herein show, by way of illustration and not by way of limitation, specific embodiments in which the subject matter may be practiced. As stated, other embodiments may be utilized and derived, such that structural and logical substitutions or changes may be made without departing from the scope of the present disclosure. Such embodiments of the subject matter of the invention may be referred to herein individually or collectively under the term "invention" merely for convenience, when in fact more than one is disclosed, without any intention to autonomously limit the scope of this application to a single invention or single inventive concept. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiment illustrated. This disclosure is intended to cover any and all adaptations or variations of the various embodiments. Combinations of the above embodiments and other embodiments not specifically described herein will be apparent to one of ordinary skill in the art upon reviewing the above description.

Claims

1. a catheter having a distal end region having a first stiffness; an obturator having a distal cannula engaging region having a stiffness matched to the first stiffness, the stiffness of the distal cannula engaging region being different from a stiffness of a tapered region distal to the distal cannula engaging region and different from a region of the obturator proximally adjacent to the distal cannula engaging region; Equipped with the obturator and catheter are configured to proximally engage one another such that the distal cannula engagement region is aligned with the distal end region of the catheter to form a combined structure to prevent the formation of a gap between the obturator and the catheter when the combined structure is bent or curved. system.

2. The system of claim 1 , wherein the distal cannula engagement region includes a stiffening component.

3. The system of claim 2 , wherein the stiffening component comprises a tubular member in the distal cannula engagement region.

4. 3. The system of claim 2, wherein the stiffening component comprises a material having a higher stiffness than a material forming the tapered region distal to the distal cannula engaging region and / or the region of the obturator proximally adjacent to the distal cannula engaging region.

5. The system of claim 2 , wherein the stiffening component comprises an internal skeleton.

6. The system of claim 1 , wherein the distal cannula engagement region comprises a length that is between 1 mm and 40 mm.

7. The system of claim 1 , wherein the distal cannula engagement region comprises a length greater than 5 mm.

8. The system of claim 1 , wherein the obturator includes an elongated guidewire channel extending down the length of the obturator.

9. The system of claim 1 , wherein the stiffness that is matched to the first stiffness is within ±5% of the first stiffness.

10. The system of claim 1 , wherein the distal cannula engaging region includes a stiffening insert within the distal cannula engaging region.

11. an elongate body including a tapered distal end and including a first material; a distal cannula engagement region of the elongate body; and the distal cannula engaging region includes an insert, the distal cannula engaging region is proximal to the tapered distal end of the elongate body and distally adjacent a second region of the elongate body, the insert including a material having a stiffness greater than a stiffness of the first material such that a stiffness of the distal cannula engaging region is greater than the stiffness of the tapered distal end and the second region. Obturator.

12. The obturator of claim 11 , further comprising an obturator lumen extending through the elongate body.

13. The obturator of claim 12 , wherein the insert includes an insert lumen coaxial with the obturator lumen.

14. The obturator of claim 11, wherein the insert comprises a length of about 1 mm to 20 mm.

15. The obturator of claim 11 , wherein the insert comprises a stiffness of between about 0.2 and about 2.5 GPa.

16. The obturator of claim 11 , wherein the stiffness of the insert is greater than twice the stiffness of the first material.

17. The obturator of claim 11 , wherein the insert is coaxial with the obturator.

18. 12. The obturator of claim 11 comprising an obturator or dilator.

19. The obturator of claim 11 , wherein the insert has an outer diameter smaller than an outer diameter of the distal cannula engaging region.

20. 12. The obturator of claim 11, further comprising a stop at a proximal end region of the obturator configured to secure the distal cannula engaging region of the obturator in alignment with a distal end region of a catheter through which the obturator is inserted.

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