Method for connecting device elements and related device having such elements - Patents.com

Abstract

A method for connecting a first medical device element to a second medical device component, comprising the steps of: changing the first medical device element from a natural state to a modified state by reducing a cross-sectional dimension of the first medical device element; and fitting a first portion of the first medical device element in the modified state into a first opening of the second medical device element, the first medical device element including a second portion that is not disposed within the first opening of the second medical device element, allowing the second portion of the first medical device element to return to its natural state.

Description

[Technical field]

[0001] The present invention relates to connecting a device element to another device element. An example of the invention relates to a method for connecting a Nitinol wire to another element, e.g., another element of a medical device, such as a therapeutic or diagnostic device, that is formed of a different material. Another example of the invention relates to a device or medical device that includes an element connected by the method described herein. [Background technology]

[0002] Nitinol has superelastic properties that give it high flexibility, shape recovery, kink resistance, high fatigue strength, corrosion resistance, and heat resistance. Therefore, Nitinol is an ideal material for medical devices and instruments, especially those with wire form. Medical devices containing Nitinol parts may be assembled by gluing, welding, crimping, and / or swaging the Nitinol parts to another component of the medical device. However, these methods can be difficult due to Nitinol's hard oxide outer layer, which limits bonding / interlocking during and after the bonding process. In order to weld or solder Nitinol to stainless steel, a filler material may be required, but this generally creates a weak point in the bond. It may also reduce the thermal properties of Nitinol that give it its shape recovery properties. Summary of the Invention

[0003] According to one example, a method for connecting a first medical device element to a second medical device element includes the steps of: modifying the first medical device element from a natural state to a modified state by reducing a cross-sectional dimension of the first medical device; engaging a first portion of the first medical device element in the modified state into a first opening of the second medical device element, wherein the first medical device element includes a second portion that is not disposed within the first opening of the second medical device element; and allowing the second portion of the first medical device element to restore to the natural state.

[0004] Alternatively, the method may further include, after the engaging step, increasing a cross-sectional dimension of a first portion of the first medical device element to a dimension of the opening. In another example, the modifying step includes applying a force to the medical device element in a direction transverse to the direction of the cross-sectional dimension, and the enabling step includes removing the force. In a natural state, the first medical device element can be dimensionally restricted from entering the first opening. The first medical device element can be a wire. The wire can include Nitinol. The modifying step can include stretching the wire such that its diameter is equal to or smaller than the width of the first opening. The second medical device element can be disc-shaped, and the first opening can include a slot extending from an outer edge of the second medical device element to a point radially inward.

[0005] In another example, the first medical device element can be a wire and the engaging step can include sliding the second medical device element over the wire via the slot. The second medical device element can include a second opening and the method can further include engaging a third portion of the first medical device element in the altered state into the second opening.

[0006] In another example, the method may further include fitting a third portion of the first medical device element into the first opening of the second medical device element. In another example, the first medical device element can be coupled to the second medical device element such that the first medical device element cannot rotate relative to the second medical device element. The first medical device element can be a drive element for driving an end effector of the medical device. The single wire can include the drive element and the end effector, and the end effector can include a snare loop. The single wire can include Nitinol, and two portions of the single wire can be fitted within the second medical device element.

[0007] According to another example, the medical device may include a nitinol wire defining a loop, a first strand, and a second strand, each of the first and second strands may include a receiving element extending proximally of the loop and coupled to the first and second strands, the receiving element including a first opening, a portion of the first strand extending into the first opening, a diameter of the portion of the first strand being smaller than a diameter of the remainder of the first strand. A portion of the second strand extending into the first opening, a diameter of the portion of the second strand being smaller than a diameter of the remainder of the second strand. The receiving element may further include a second opening, a portion of the second strand extending into the second opening, a diameter of the portion of the second strand being smaller than a diameter of the remainder of the second strand. The diameter of the portion of the first strand may be smaller than a diameter of a portion of the nitinol wire defining the loop.

[0008] According to another example, the medical device may include a shaft, a handle connected to a proximal portion of the shaft, a nitinol wire extending from the handle to the shaft, and a receiving element, wherein the receiving element is disposed within the handle, or shaft, and a portion of the nitinol wire extends through the receiving element, wherein the diameter of the portion of the nitinol wire is smaller than the diameter of the remainder of the nitinol wire.

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 2 is a side view of an unmodified Nitinol wire according to one embodiment. [Figure 1B] FIG. [Figure 2A] FIG. 1B is a side view of the nitinol wire of FIG. 1A in an elongated state. [Figure 2B] 2B is a front view of the receiver of FIG. 1B including the Nitinol wire of FIG. 2A in an extended state. [Figure 2C]FIG. 2C is a top view of the receiver and nitinol wire of FIG. 2B. [Figure 2D] FIG. 2C is a perspective view of the receiver and Nitinol wire of FIG. 2B. [Figure 3A] 1 is a perspective view of a medical device according to one embodiment. [Figure 3B] 3B is a cross-sectional view of the receiver of the device of FIG. 3A taken along line 3B-3B. [Figure 3C] 1 is a perspective view of a medical device according to another embodiment. [Figure 3D] 3D is a cross-sectional view of the receiver of the device of FIG. 3C taken along line 3D-3D. [Figure 4] 1 is a perspective view of a medical device according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same or similar reference numbers will be used throughout the drawings to refer to the same or similar parts. The term "distal" refers to the portion of the device that is furthest from the user when introducing the device into the body of a subject (e.g., a patient). In contrast, the term "proximal" refers to the portion of the device that is closest to the user when the device is placed inside the subject's body.

[0012] Both the general description above and the detailed description below are exemplary and explanatory only and are not intended to limit the claimed features. As used herein, the terms "comprises," "contains," "has," "includes," or other variations thereof mean that a process, method, article, or device that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or device. In the present invention, relative terms such as, for example, "about," "substantially," "generally," and "approximately" are used to indicate a possible variation of ±10% in a stated value or characteristic.

[0013] Aspects of the present invention may address one or more of the limitations in the art. However, the scope of the present invention is defined by the appended claims, not the ability to address a particular problem. The present invention relates to a method for connecting device elements to other elements, and to a medical device / instrument including elements connected by this method. In an exemplary embodiment, the device element is a wire, such as a wire containing Nitinol, a nickel-titanium alloy that has superelastic properties. However, the present invention is not limited to wires containing Nitinol. Device elements, such as wires suitable for use in the methods and devices of the present invention, may include any material that can be stretched / extended when a force is applied and return to its original unstretched form when the force is removed. Throughout this specification, embodiments refer to wires made of Nitinol. However, any of the materials mentioned herein and other suitable materials may be used in the methods and devices of the present invention.

[0014] In the exemplary embodiments described herein, the element that is modified to couple to another device element is a wire. Other elements that can expand in one direction and contract in another direction can be used in devices and methods according to embodiments of the present invention.

[0015] According to exemplary embodiments, Nitinol elements may be modified to couple to other materials and elements via receivers. Thus, in a manner described in more detail below, Nitinol components may be coupled to other materials without the use of fillers or adhesives or exposure to heat. Such receivers may be implemented into a variety of medical devices or instruments that contain Nitinol, such as endoscopes, instruments having end effectors, and the like.

[0016] 1A-2D, an example of a method for connecting / fixing the Nitinol wire 100 to the receiver 200 will be described. The Nitinol wire 100 has a diameter D. The diameter D is not particularly limited and may be in the range of about 0.02 inches (about 0.51 mm) to 0.04 inches (about 1.02 mm), for example, about 0.029 inches (about 0.74 mm). The Nitinol wire 100 has a circular cross section, but is not particularly limited thereto. The diameter D is greater than the width W of the opening 210 of the receiver 200. The receiver 200 is disc-shaped and is any suitable material, such as stainless steel. The receiver 200 is formed of a material different from the wire 100. The opening 210 communicates with a slot 215 having a width W over its entire length. The width W should be smaller than the diameter D of the wire 100, but is not particularly limited thereto and may be, for example, about 0.028 inches (about 0.71 mm). The slot 215 extends from the outer surface to an end point 220, which may be located at or about the center point of the disc-shaped receiver 200. The end point 220 may be shaped to correspond to the cross-sectional shape of the Nitinol wire 100. However, the Nitinol wire 100, in its unaltered state with no applied force, does not fit within the receiver 200, as shown by the dotted outline representing the outer circumference of the wire 100 in FIG. 1B.

[0017] To couple the nitinol wire 100 to the receiver 200, the nitinol wire 100 may be modified in any suitable manner to fit the opening 210 and slot 215 of the receiver 200. For example, the nitinol wire 100 may be stretched to form a reduced diameter nitinol wire 100' having a diameter D' as shown in FIG. 2A. The extent to which the nitinol wire 100 is reduced to the nitinol wire 100' is not particularly limited, so long as the nitinol wire 100' has a diameter D' that is equal to or less than the width W of the opening 210 of the receiver 200. For example, the diameter D' may range from about 0.02 inches (about 0.51 millimeters) to 0.04 inches (about 1.02 millimeters), such as about 0.028 inches (about 0.71 millimeters), and is equal to or less than the width W. Additionally, the nitinol wire 100 may be modified / stretched in any suitable manner. For example, one or both ends of the nitinol wire 100 may be secured to a hydraulic press or any other suitable tensioning fixture. The hydraulic press or tensioning fixture may then be used to elongate the nitinol wire 100 by superelastically stretching it. The nitinol wire 100 may be stretched to the extent described above before the nitinol wire 100 reaches its breaking point.

[0018] Since the elongated nitinol wire 100' has a diameter D', the elongated nitinol wire 100' may then be fitted / inserted into the receiver 200 through the opening 210 (shown in FIGS. 2A-2B). Due to the shape recovery properties of nitinol, the nitinol wire 100' is fitted / slid into the opening 210 and slot 215 before recovering to its original dimensions, e.g., diameter D. Thus, the nitinol wire 100' may be coupled to the receiver 200 while maintaining the diameter D'. The manner in which the nitinol wire 100' is attached to the receiver 200 is not particularly limited. For example, the receiver 200 may be slid over the nitinol wire 100' through the opening 210 until the nitinol wire 100' reaches the end 220 of the slot 215. Furthermore, the receiver 200 is not limited to receiving one nitinol element, e.g., a single nitinol wire, but may be configured to receive multiple nitinol wires. For example, multiple nitinol wires can be stacked within the slot 215 and / or the receiver 200 can include multiple openings and slots arranged radially around the circumference of the receiver 200. The opening 210 of the receiver 200 is not particularly limited to a slot. The opening 210 can be any suitable opening capable of receiving the wire 100'. For example, instead of a slot, the opening 210 of the receiver 200 can be a through hole through which the wire 100' can be threaded in an extended state.

[0019] Once the nitinol wire 100' is attached to the receiver 200, the force applied to the nitinol wire 100' may be removed to allow the nitinol wire 100' to move to a relaxed state. This allows the portion of the nitinol wire 100' not fitted within the slot 215 to return to its original dimension, for example, diameter D. The portion of the nitinol wire 100' fitted within the slot 215 expands to a diameter corresponding to the width W. For example, if the diameter D' is less than the width W, the portion of the nitinol wire 100' fitted within the slot 215 may expand to fill the width W. As a result, the nitinol wire 100' is securely fitted within the slot 215 of the receiver 200. In an exemplary embodiment, the receiver 200 may be coupled to the nitinol wire 100' such that it cannot rotate relative to the nitinol wire 100'. The remaining portion of the nitinol wire 100' will return to its original diameter D, e.g., about 0.029 inches (about 0.74 mm), due to its shape recovery properties. As a result, the receiver 200 is restrained from moving along the longitudinal axis of the nitinol wire 100' due to the interference fit between the wire 100' and the receiver 200.

[0020] As noted above, the device element that is modified and coupled to another device element is not limited to being a wire, but may be any suitable shape or form having a first configuration that prevents the element from fitting into receiver 200 through opening 210, and a second configuration that is modified to fit into opening 210.

[0021] Similarly, the receiver 200 is not limited to a disk shape, and the opening 210 and slot 215 are not limited to those shown in the drawings. The receiver 200 may be of any suitable material and form / shape. The opening 210 and slot 215 may be of any suitable width and shape, so long as they are configured to receive the device element in its second modified form. In some examples, the receiver 200 may include multiple openings and slots having different shapes and / or dimensions. Additionally, as noted above, the change of the device element from the first form to the second form is not limited to stretching. The device element may be modified in any suitable manner to fit the opening 210.

[0022] The above methods may be used to connect device components, such as Nitinol components, to other medical device components, such as medical devices or medical device receivers. Examples of such medical devices and devices are described below with reference to Figures 3A-4.

[0023] FIG. 3A shows a medical device 50 including a single nitinol wire 100″ used for the drive element 51 and the end effector 54. The wire 100″ extends distally from another medical device element, such as a handle (not shown). The drive element 51 is proximal to the end effector 54. The drive element 51 may be coupled to the handle (not shown) at the proximal end of the device in any suitable manner. The drive element 51 and the end effector 54 may move linearly along the longitudinal axis of the element 51. Both the element 51 and the end effector 54 may extend through a sheath (not shown) of the device. The loop of the end effector 54 may be opened and closed by moving the end effector 54 in and out of the sheath (not shown).

[0024] The nitinol wire 100'' may be in the form of a wire, cable, or ribbon and may be formed in any suitable cross-sectional shape or dimensions to accommodate the receiver 61. The portion of the wire 100'' proximal to the end effector 54 is the first strand 52 of the drive element 51. The portion of the nitinol wire 100'' distal to the drive element 51 defines the end effector 54, e.g., a distal loop in a plane. The size and shape of the end effector 54 is not particularly limited and may be, for example, circular, oval, teardrop shaped, etc. The distal-most end of the end effector 54 may include a tip 55. The tip 55 may be a distal protrusion, thereby forming an atraumatic distal end. However, the tip 55 is not particularly limited or necessary in the end effector 54. In some other embodiments, the end effector 54 may have an atraumatic distal end.

[0025] A distal portion of the nitinol wire 100'' is looped back on itself to form the loop of the end effector 54. The remainder of the wire 100'' distal to the portion of the wire 100'' forming the end effector 54 extends straight to form a second strand 53. The first strand 52 and the second strand 53 are parallel to each other and both are proximal to the loop 54. The length of the second strand 53 is not particularly limited. The strands 52, 53 may be spaced apart, in contact with each other, or any suitable distance apart, to accommodate the opening of the receiver 60.

[0026] 3A-3B, the medical device 50 further includes a receiver 60. The receiver 60 may be formed of any suitable material, such as, for example, stainless steel. The receiver 60 is an annular / ring-like element including an opening 61. However, the receiver 60 is not specifically limited to being a ring, and may be any suitable shape and / or size, as described above. The receiver 60 is a complete closed ring. However, in another exemplary embodiment, the receiver 60 may be a partial ring including a break in its annular structure. The break may be any suitable distance that allows the receiver 60 to receive and hold the strands 52, 53. The opening 61 may be any suitable shape, such as, for example, circular, rectangular, and may be a shape that matches the cross-sectional shape of the strands 52, 53. The opening 61 should have a width or diameter that is less than the total diameter of the combined diameters of the strands 52, 53, but is not specifically limited thereto. In another exemplary embodiment, the receiver 60 may have two separate openings for the corresponding strands 52, 53. In such an embodiment, both openings may have a diameter smaller than the diameter of each of the strands 52,53.

[0027] The strands 52, 53 of the nitinol wire 100'' are coupled to the receiver 60 by the coupling methods described above. In their unaltered state, e.g., in a first configuration, the strands 52, 53 have a total width / diameter that is greater than the width / diameter of the opening 61. The strands 52, 53 are modified to a second configuration, e.g., stretched / contracted, and coupled to the receiver 60. As shown in FIG. 3B, the strands 52, 53 are contracted so that they fit within the opening 61. In some instances, the strands 52, 53 are stretched and inserted into the opening 61 sequentially or simultaneously. In other instances, the nitinol wire 100'' is stretched prior to forming the distal loop 54, such that the strands 52, 53 are already in a contracted / stretched state when coupled to the receiver 61. Regardless of the method performed, the modification to the second configuration involves a reduction in the cross-sectional dimensions of the device elements, e.g., the strands 52, 53.

[0028] After the strands 52, 53 are crimped, the receiver 60 is mounted over the crimped strands 52, 53 (or the Nitinol wire 100″ that was crimped prior to forming the loop 54) through the opening 61. The manner in which the receiver 60 is mounted over the strands 52, 53 is not particularly limited. In some examples, the receiver 60 is mounted over the crimped strands 52, 53 before the drive element 51 is coupled to another device element, such as a handle (not shown). In other examples, the receiver 60 is mounted over the crimped Nitinol wire 100″ prior to forming the loop of the end effector 54. The looped portion of the Nitinol wire 100″ (that forms the second strand 53) can then be slid into the opening 61 during or after the formation of the end effector 54. In another exemplary embodiment where receiver 60 is a partial ring, receiver 60 can be slid through a slit in the partial ring onto reduced diameter strands 52, 53. Receiver 60 can be mounted onto strands 52, 53 in a variety of other ways beyond the above examples.

[0029] After mounting the receiver 60 on the strands 52,53, the force applied to the strands 52,53 may be removed so that the strands 52,53 may transition to a relaxed state. This allows the portions of the strands 52,53 mounted within the openings 61 to expand to the extent permitted by the openings 61. However, the mating portions of the strands 52,53 do not expand to their original diameter due to the spatial constraints of the openings 61. Meanwhile, the remaining portions of the strands 52,53 that are not fitted within the openings 61 will return to their original dimensions, e.g., diameter, due to the shape recovery properties of the nitinol wire 100''. Thus, the receiver 60 may be restrained from moving along the longitudinal axis of the strands 52,53 due to the interference fit between the strands 52,53 and the receiver 200.

[0030] 3C-3D show a similar device to that shown in FIGS. 3A-3B, except that receiver 60' differs from receiver 60. Receiver 60' includes two openings 61', 62. Openings 61', 62 are configured to receive first and second strands 52, 53, respectively. Thus, opening 61' may be located directly below opening 62. Openings 61', 62 are spaced apart according to the distance between strands 52, 53. Opening 61' is a clamp-like opening that receives first strand 52. Opening 61' may be any suitable shape to accommodate first strand 52. Opening 61' may be any suitable width that is equal to or less than the width / diameter of first strand 52 when unmodified. Opening 62 receives second strand 53. Opening 62 is within the structure of receiver 60 and extends longitudinally. Thus, unlike opening 61', opening 62 is a fully enclosed opening. Opening 62 may be of any suitable shape to accommodate second strand 53. Opening 62 may be of any suitable width / diameter that is smaller than the width / diameter of second strand 53 when in an unmodified state.

[0031] The strands 52, 53 of the nitinol wire 100'' are also coupled to the receiver 60' via the coupling methods described above. For example, the second strand 53 is modified, e.g., stretched / contracted, so that the receiver 60' can be slid onto the second strand 53 through the opening 62. The receiver 60' can be attached to any portion of the second strand 53 as long as it is proximal to the distal loop 54. In some instances where the width of the opening 61' is smaller than the width / diameter of the first strand 52, the first strand 52 is also modified, e.g., stretched / contracted, so that the first strand 52 can fit within the clamp-like opening 61'. In other instances where the width of the opening 61' is equal to or approximately equal to the width / diameter of the first strand 52, the unmodified first strand 52 is fitted within the clamp-like opening 61' by any suitable method.

[0032] 4 illustrates an example of a medical instrument, such as an endoscope, that includes a Nitinol component that is coupled to other medical instrument elements, such as a receiver, by the methods described above. The endoscope 10 includes a flexible shaft 20, a tip 30 at the distal end of the endoscope 10, and an articulation joint 50 disposed between and connecting the flexible shaft 20 and the tip 30. A handle 40 or another device for driving or controlling the endoscope 10, and any tools or devices associated with the endoscope 10, are connected to the proximal end of the flexible shaft 20.

[0033] A number of drive elements, such as Nitinol steering wires 48, 49 suitable for medical procedures, may extend distally from the handle 40. The wires 48, 49 may be supported and secured by medical device elements, such as a number of receivers 45, 47, 25, and 27, by the above-described coupling methods. Thus, the wires 48, 49 may be securely fitted into the receivers 45, 47, 25, and 27 by an interference fit between the wires and the receivers. The proximal receivers 45, 47 are positioned in a suitable location within the handle 40. The method of positioning the receivers 45, 47, e.g., molding, bonding, etc., is not particularly limited. The receivers 45, 47 may be any of the receivers described above or variations thereof. The distal receivers 25, 27 are positioned within the shaft 20. Additionally or alternatively, the distal receivers 25, 27 may be positioned in any suitable location within the tip 30 or articulation joint 50. There is no particular limitation on the method of arranging the receivers 25, 27, e.g., molding, gluing, etc. The receivers 25, 27 may be any of the receivers described above or variations thereof.

[0034] The Nitinol wires 48, 49 may be indirectly coupled to first and second actuators 42, 43 which control articulation in multiple directions of the articulation joint 50. The actuators 42, 43 may be, for example, rotatable knobs that rotate about their axes to push or pull the Nitinol steering wires 48, 49.

[0035] Alternatively or additionally, a user may manipulate the steering wires 48, 49 independently of the handle 40. The distal ends of the steering wires 48, 49 extend through the flexible shaft 20 and terminate at the articulation joint 50 and / or the tip 30. For example, one or more steering wires 48, 49 may be coupled to the articulation joint 50 while one or more other steering wires 48, 49 are attached to the tip 30. Actuation of the steering wires 48, 49 may control the articulation joint 50, the tip 30, and / or elements attached to the tip 30, such as an end effector (not shown). Additionally, one or more electrical cables (not shown) may extend from the proximal end of the endoscope 10 to the tip 30 to provide electrical control to imaging, illumination, and / or other electrical devices on the tip 30, as well as to deliver imaging signals proximally from the tip 30 for processing and display on a display. The handle 40 may include ports 44, 46 for introducing and / or removing instruments, fluids, or other substances from a patient. Port 44 may be used for the introduction of instruments. Port 46 may be connected to an umbilicus for introducing fluid suction and / or wiring for electronic components.

[0036] Those skilled in the art will appreciate that various modifications and variations can be made to the disclosed stapling mechanism without departing from the scope of the invention. For example, the configuration of the coupler, actuator, and stapler can be modified to suit any medical device and are not limited to the examples set forth herein. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the scope and spirit of the invention being indicated by the following claims.

Claims

1. modifying a first medical device element from a natural state to an altered state by reducing a cross-sectional dimension of a first portion and a second portion of the first medical device element from a first cross-sectional dimension in the natural state to a second cross-sectional dimension in the altered state, the first cross-sectional dimension being greater than a dimension of a first opening of a second medical device element and the second cross-sectional dimension being less than or equal to a dimension of the first opening of the second medical device element; mating the first portion of the first medical device element in the altered state with the first opening of the second medical device element, the first medical device element including a second portion not disposed within the first opening of the second medical device element; increasing a cross-sectional dimension of the first portion of the first medical device element to a dimension of the first opening after the engaging step; and returning the second portion of the first medical device element to the natural state; A method for connecting a first medical device element to a second medical device element, wherein the first medical device element is a drive element for driving an end effector of a medical device, and the first portion and the second portion are formed from a single wire.

2. The method of claim 1 , wherein the modifying step comprises applying a force to the first medical device element in a direction perpendicular to the direction of the cross-sectional dimension, and the restoring step comprises removing the force.

3. The method of claim 1 or 2, wherein in the natural state, the first medical device element is dimensionally restricted from entering the first opening.

4. The method of claim 1 , wherein the single wire comprises Nitinol.

5. The method of claim 4 , wherein the modifying step includes the step of stretching the single wire.

6. The method of any one of claims 1 to 5, wherein the second medical device element is disc-shaped and the first opening comprises a slot extending from an outer edge of the second medical device element to a point radially inward of the outer edge.

7. The method of claim 6, wherein the fitting step includes sliding the second medical device element over the single wire through the slot.

8. The method of any one of claims 1 to 7, wherein the second medical device element includes a second opening, and the method further includes fitting a third portion of the first medical device element in the changed state into the second opening, the third portion of the first medical device element including a first cross-sectional dimension in the natural state that is larger than the second opening, and the third portion including a second cross-sectional dimension in the changed state that is smaller than or equal to the second opening.

9. The method of claim 8 , further comprising mating the third portion of the first medical device element with the first opening of the second medical device element.

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