Apparatus and methods for stent manufacture

Apparatus and methods for manufacture of bifurcated stents are disclosed. The apparatus can include a base having a first mount, a second mount and a third mount. The first mount, the second mount and the third mount can be configured to secure a first mandrel, a second mandrel and a third mandrel at positions relative to one another. The mandrels may be configured to receive two or more mono-tubular stents so that the stents or components of the stents may be secured to one another to form a bifurcated stent.

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Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present inventions relates to medical devices and, more particularly, to apparatus and methods for manufacture of bifurcated stents.

2. Background of the Related Art

Stents and similar implantable medical devices, collectively referred to hereinafter as stents, are generally radially expandable endoprostheses. They are typically used to obtain and maintain the patency of the body passageway while maintaining the integrity of the passageway. Stents have provided doctors with a desirable alternative to the more invasive surgeries historically required to open obstructed passageways within the body. With the tendency being to avoid invasive surgeries, their use and range of applications has steadily increased.

Stents are typically tubular devices. That is, they comprise a body or wall that defines a lumen. Stents are frequently made of a thin-walled metallic or woven material and have a pattern of apertures, openings or holes defined around the circumference of the stent along most of its length. Typically, the pattern of apertures, openings or holes is configured to permit the stent to move from a contracted to an expanded position. Stents may be constructed from a variety of materials such as stainless steel, cobalt-chromium alloys, such as Elgiloy, nickel-titanium alloys, such as Nitinol, shape memory polymers, among other materials. The materials are typically selected for their biocompatibility among other physical characteristics that may be desirable for particular applications.

Stents are typically configured to be implanted translumenally and radially enlarged after being positioned within a lumen. They may be implanted in a variety of bodily lumens or vessels such as within the vascular system, urinary tracts, bile ducts, etc. The stent may provide a prosthetic intralumenal wall or wall support. Some stents are particularly adapted to reinforce blood vessels and to prevent restenosis following angioplasty in the vascular system. In the case of a stenosis, a stent may provide an unobstructed conduit for blood to move through the stenotic region of the vessel. In other variations, a stent may be used to treat an aneurysm by removing the pressure on a weakened part of an artery so as to reduce the risk of embolism, or of the natural artery wall bursting.

Stents may be formed in a variety of methods. In one exemplary methodology, a stent may be formed by etching or cutting the stent pattern from a tube or section of stent material. In another exemplary methodology, a sheet of stent material maybe cut or etched according to a desired stent pattern whereupon the sheet may be rolled or otherwise formed into the desired tubular or bifurcated tubular shape of the stent. In yet another exemplary methodology, one or more wires or ribbons of stent material may be braided or otherwise formed into a desired shape and pattern.

Early, stents typically shared the common design of being mono-tubular. These mono-tubular stents were suitable axial delivery and implantation within a bodily lumen. Recently, smaller stents have been utilized. These smaller stents have been inserted into coronary arteries after a coronary angioplasty procedure. Coronary angioplasty is a medical procedure used to treat blocked coronary arteries as an alternative to a coronary bypass operation. However, the need to manufacture these smaller stents has introduced a number of complications into stent manufacture one of which is the need for greater precision in the manufacturing process. In one technique, stents are cut with laser beams from small diameter tubes. As they are formed from small diameter tubes, laser cut stents manufactured from such processes have typically been mono-tubular.

Within the vasculature however, it is not uncommon for stenoses to form at any of a wide variety of vessel bifurcations. A bifurcation is an area of the vasculature or other portion of the body where a first (or parent) vessel is bifurcated into two or more branch vessels. Bifurcations exist within the body in a wide variety of configurations, angles, and vessel diameters. Where a stenotic lesion or lesions form at such a bifurcation, the lesion(s) can affect only one of the vessels (i.e., either of the branch vessels or the parent vessel) two of the vessels, or all three vessels.

Unfortunately, mono-tubular stents are not optimal for use at a bifurcation body passageway or about a side branch of a body passageway. When implanted, mono-tubular stents can shield side branches emanating from a bodily lumen. In these cases, there is an increased risk of closure of one of the side branches or arm of the bifurcation and, at a minimum, the increased resistance to the movement of fluid through the obscured branch or arm. Thus, a need exists for bifurcated stents to support these areas. However, the manufacture of bifurcated stents can be complicated and may introduce a number of variables that are not necessarily considered when manufacturing mono-tubular stents. These complications can be exacerbated when the bifurcated stent is of a relatively small diameter. Accordingly, a need exists for apparatus and methods for manufacture of bifurcated stents.

SUMMARY OF THE INVENTION

This Summary of the Invention capsulizes some of the claimed aspects of the present inventions. Additional details of aspects of the present inventions and/or additional embodiments of the present inventions are found in the Detailed Description of the Invention and associated Figures. Apparatus and methods in accordance with the present inventions may satisfy one or more of the needs listed in the Background of the Invention and will in certain configurations provide additional improvements and advantages that will be recognized by those skilled in the art upon review of the following Detailed Description of the Invention and associated Figures.

In one aspect, the present inventions may provide a fixture for manufacture of a bifurcated stent. The fixture may include a base having a first mount, a second mount, and a third mount. The base may define a lower surface adapted to be stably received on a work surface. A first mandrel, a second mandrel and a third mandrel may be secured to the base. The base may further define an orifice positioned about a central point and extending through the base between the lower surface and an upper surface. Alternatively to defining an orifice positioned about a central point, the base may define a cavity positioned about a central point and extending into the upper surface of the base.

The first mandrel may be secured to the first mount at one of a plurality of desired positions along the first mandrel. The first mount may define at least a first mandrel receiving passage in which the first mandrel may be secured. The first mandrel may be slidably positioned within the first mandrel receiving passage. The first mandrel receiving passage may define a first longitudinal axis. The second mandrel may be secured to the second mount at one of a plurality of desired positions along the second mandrel. The second mount may define at least a second mandrel receiving passage in which the second mandrel may be secured. The second mandrel may be slidably positioned within the second mandrel receiving passage. The second mandrel receiving passage may define a second longitudinal axis. The third mandrel may be secured to the third mount at one of a plurality of desired positions along the third mandrel. The third mount may define at least a third mandrel receiving passage in which the third mandrel may be secured. The third mandrel may be slidably positioned within the third mandrel receiving passage. The third mandrel receiving passage may define a third longitudinal axis. The first longitudinal axis, the second longitudinal axis, and the third longitudinal axis may intersect at a central point. Each of the first mandrel, the second mandrel and the third mandrel can be securable in at least one position that places the first tip of the first mandrel, the second tip of the second mandrel, and the third tip of the third mandrel adjacent to one another.

A first set screw lumen may be defined by the first mount. The first set screw lumen intersecting the first mandrel receiving passage. A first set screw may be threadably received within the first set screw lumen to secure the first mandrel relative to the base.

A second set screw lumen may be defined by the second mount. The second set screw lumen intersecting the second mandrel receiving passage. A second set screw may be threadably received within the second set screw lumen to secure the second mandrel relative to the base.

A third set screw lumen may be defined by the third mount. The third set screw lumen intersecting the third mandrel receiving passage. A third set screw may be threadably received within the third set screw lumen to secure the third mandrel relative to the base.

The first mandrel receiving passage may include a first internal thread. The first internal thread may be configured to receive including a first external thread defined on an outer surface of the first mandrel. The first external thread of the first mandrel may be threadably received within the first internal thread of the first mandrel receiving passage to permit the rotational positioning of the first mandrel within the first mandrel receiving passage. A first knob may be secured to a first outer end of the first mandrel to assist a user at gripping and/or rotating the first mandrel.

The second mandrel receiving passage may include a second internal thread. The second internal thread may be configured to receive including a second external thread defined on an outer surface of the second mandrel. The second external thread of the second mandrel may be threadably received within the second internal thread of the second mandrel receiving passage to permit the rotational positioning of the second mandrel within the second mandrel receiving passage. A second knob may be secured to a second outer end of the second mandrel to assist a user at gripping and/or rotating the second mandrel.

The third mandrel receiving passage may include a third internal thread. The third internal thread may be configured to receive including a third external thread defined on an outer surface of the third mandrel. The third external thread of the third mandrel may be threadably received within the third internal thread of the third mandrel receiving passage to permit the rotational positioning of the third mandrel within the third mandrel receiving passage. A third knob may be secured to a third outer end of the third mandrel to assist a user at gripping and/or rotating the third mandrel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of an embodiment of a laser welding apparatus including a fixture in accordance with the present inventions positioned on a work surface;

FIG. 2 illustrates a perspective view of an embodiment of a bifurcated stent manufactured using apparatus in accordance with the present invention;

FIG. 3A illustrates a perspective view of an embodiment of a fixture in accordance with the present invention;

FIG. 3B illustrates a top view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 3A;

FIG. 3C illustrates a side view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 3A;

FIG. 3D illustrates a cross-sectional side view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 3A;

FIG. 4A illustrates a perspective view of another embodiment of a fixture in accordance with the present invention;

FIG. 4B illustrates a top view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 4A;

FIG. 4C illustrates a side view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 4A;

FIG. 4D illustrates a cross-sectional side view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 4A;

FIG. 5A illustrates a perspective view of yet another embodiment of a fixture in accordance with the present invention;

FIG. 5B illustrates a top view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 5A;

FIG. 5C illustrates a side view of an embodiment of a fixture in accordance with the present inventions similar to the embodiment of FIG. 5A; and

FIG. 6 illustrates a top view of mandrels of a fixture in accordance with the present inventions positioning stents to be welded to one another.

All Figures are illustrated for ease of explanation of the basic teachings of the present invention only; the extensions of the Figures with respect to number, position, relationship and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following description has been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following description has been read and understood.

Where used in various Figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “top,” “bottom,” “right,” “left,” “forward,” “rear,” “first,” “second,” “inside,” “outside,” and similar terms are used, the terms should be understood to reference only the structure shown in the drawings and utilized only to facilitate describing the illustrated embodiments. Similarly, when the terms “proximal,” “distal,” and similar positional terms are used, the terms should be understood to reference the structures shown in the drawings as they will typically be implemented by a manufacturer of stents using apparatus and methods in accordance with the present inventions.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary laser welding apparatus 100 including a fixture 10 in accordance with the present inventions positioned on a work surface 106. Laser welding apparatus 100 generally includes a laser generator 102 having a laser source and optical focusing mechanism. The laser generator 102 generates a laser beam 110. The laser beam 110 from the laser generator 102 is directed through the laser welding apparatus 100 to a guide 104 which directs the laser beam through an aperture or lens 108 toward a target positioned on work surface 106. As illustrated, the laser beam 110 is directed downward in an orientation which is substantially perpendicular to a plane defined by the work surface 106 for exemplary purposes. A fixture 10 may be positioned on the work surface 106 to secure one or more components of a bifurcated stent 210 at a location that will permit the laser beam 110 to be directed at the desired aspects of the bifurcated stent 210. Some components of a bifurcated stent 210 are shown in FIGS. 2 and 6. The components include stents 212, 214, 216 which may be secured to fixture 10 for welding. As illustrated for exemplary purposes, the fixture 10 securing the stents 212, 214, 216 is positioned on work surface 106 so that the laser beam may be directed toward the location on or between one or more of stents 212, 214, 216 be welded.

An embodiment and components of a bifurcated stent 210 manufactured using apparatus and methods in accordance with the present inventions are generally illustrated in FIG. 2 for exemplary purposes. The elements shown in FIG. 2 are provided solely for exemplary purposes and may be out of the proper proportions for particular stenting applications. These proportions have been selected for ease of illustration of the particular elements. The bifurcated stent 210 may be particularly configured for implantation in a blood vessel. In one aspect, the bifurcated stent 210 may be adapted to maintain the lumen of a blood vessel in an open configuration. In one aspect, the bifurcated stent 210 may be configured for use in a coronary angioplasty.

As particularly illustrated in FIG. 2, the bifurcated stent 210 is positioned in a radially expanded configuration. As illustrated for exemplary purposes, the bifurcated stent 210 generally includes a first mono-tubular stent 212, a second mono-tubular stent 214, and a third mono-tubular stent 216 welded to one another at a junction 230 by first intraconnect 232, second intraconnect 234 and third intraconnect 236 in a generally radial arrangement. Each of the mono-tubular stents 212, 214, 216 defines a passage 222, 224, 226. The first mono-tubular stent 212 defines a first passage 222; the second mono-tubular stent 214 defines a second passage 224; and the third mono-tubular stent 216 defines a third passage 226.

The passages 222, 224, 226 generally extend between the proximal ends and distal ends and generally in a direction along the longitudinal axis 242, 244, 246 of the respective mono-tubular stents 212, 214, 216. The longitudinal axis 242, 244, 246 have been illustrated as relatively positioned during manufacture at 120 degree intervals about junction 30 for exemplary purposes. Those skilled in the art will recognize that a variety of relative angles distinct from those illustrated may be advantageous for various applications. Further, those skilled in the art may recognize that the mono-tubular stents 212, 214, 216 do not have to be fixed in a co-planar orientation relative to one another by the fixture 10. For example, the longitudinal axis 242 of first mono-tubular stent 212 manufactured at a 180 degree angle from the longitudinal axis 44 of the second mono-tubular stent 214. In addition, the three mono-tubular stents 212, 214, 216 are illustrated as having been manufactured in a substantially co-planar configuration. Those skilled in the art will recognize that a bifurcated stent 210 may be manufactured with a mono-tubular stent 212, for example, directed outside the plane defined by the other two mono-tubular stents 214, 216 without departing from the scope of the present inventions. Further, those skilled in the art will understand that one or more of the mono-tubular stents 212, 214, 216 may include one or more curves along its longitudinal axis which may have advantages in particular applications. Further as illustrated, the mono-tubular stents 212, 214, 216 are selected to be of generally equivalent in size and general configuration only for exemplary purposes. Those skilled in the art will recognize varying the diameter, length, cell patterns, or general configuration may have advantages in particular applications. For example, the length and diameter for each of the stents may be optimized for both deliverability of the stent and vessel coverage for particular applications.

Each of the illustrated stents 212, 214, 216 further includes one or more intraconnects 232, 234, 236 at their proximal ends for exemplary purposes. These intraconnects 232, 234, 236 may be used to interconnect the stents 212, 214, 216 into a bifurcated stent 210. Such interconnects are described in more detail in a U.S. patent application, entitled Bifurcated Stenting Apparatus and Methods and assigned Ser. No. 11/049,323 the disclosure of which is hereby incorporated by reference in its entirety. Those skilled in the art will recognize additional structures and configurations for stents or components thereof that may utilize a fixture 10 in accordance with the present inventions in their assembly into a bifurcated stent.

As particularly illustrated, each of the stents 212, 214, 216 includes a pair of intraconnects 232, 234, 236 at their proximal ends for exemplary purposes. For purposes of describing the elements and construction of the bifurcated stent 210, the term proximal shall refer to the end of the components adjacent to junction 230 and the term distal shall refer to the end opposite the proximal end of each element. The first stent 212 includes a first intraconnect 232, the second stent 214 includes a second intraconnect 234, and the third stent 216 includes a third intraconnect 236. The intraconnects 232, 234, 236 are used to weld each of the stents 212, 214, 216 relative to one another to form a bifurcated stent 210. Intraconnects 232, 234, 236 are configured to be secured at their distal ends to the proximal ends of the stents 212, 214, 216 and at their proximal ends to one another. Typically, the intraconnects 232, 234, 236 are secured to one another by laser welding as is generally illustrated throughout the figures for exemplary purposes. However, the intraconnects 232, 234, 236 may be welded using alternative methods, adhesively bonded or otherwise secured to one another using a fixture 10 in accordance with the present inventions as will be understood by those skilled in the art upon review of the present disclosure.

Fixtures 10 in accordance with the present inventions generally include a base 12 relatively securing the position of at least two mounts 20, 30, 40. A mandrel 22, 32, 42 is secured within each of the mounts 20, 30, 40. The mounts 20, 30, 40 secure the relatively position at least two mandrels 22, 32, 42 to permit components of a bifurcated stent 210 to be precisely positioned and secured relative to one another. Fixtures 10 in accordance with the present inventions may facilitate manufacture of bifurcated stent 210 by permitting the precision assembly of three independently fabricated mono-tubular stents 212, 214, 216. The manufacture of a bifurcated stent 210 from two or more mono-tubular stents 212, 214, 216 can allow for the use of conventional mono-tubular stent manufacturing techniques to provide the precursors of a bifurcated stent 210. This can reduce the need for special or complex tooling typically required for manufacture and/or assembly of bifurcated stents. Embodiments and components of embodiments of fixtures 10 and methods in accordance with the present inventions are generally illustrated in FIGS. 1 and 3A to 6.

The present inventions are generally described with reference to the figures wherein the same numbers indicate similar, identical or analogous elements in different figures and within individual figures. The elements identified in the figures may be drawn out of the proper proportions for particular applications. However, these proportions have been selected for ease of illustration and description. Further, the figures are intended to be illustrative rather than limiting and are included to facilitate the explanation of the apparatus of the present inventions not to limit the scope of the claims.

Exemplary embodiments of fixtures 10 in accordance with the present inventions are generally illustrated in FIGS. 1 and 3A to 6. In accordance with the present inventions, fixtures 10 are generally configured to position two or more mono-tubular stents 212, 214, 216. The two or more mono-tubular stents 212, 214, 216 may be positioned relative to one another to permit the mono-tubular stents 212, 214, 216 to be secured to one another by techniques such as laser welding, adhesive bonding, among other techniques. As illustrated, the fixture 10 generally includes a first mandrel 22, a second mandrel 32, and a third mandrel 42 over which one or more mono-tubular stents 212, 214, 216 may be secured. The mandrels 22, 32, 42 are secured to a base 12 to properly position the stents 22, 32, 42 relative to one another.

The base 12 may be modular or a unitary component. The base 12 is typically sized to be easily handled and to permit its positioning on a work surface 106 of a laser welding apparatus 100. The base 12 includes a lower surface 14 configured to stably support the base 12 when the base is positioned on a work surface 106 as shown in FIG. 1. In one aspect, the lower surface 14 may be substantially planar to permit the base to stably rest on a flat surface. In another aspect, the lower surface 14 may define one or more feet or extensions upon which the base 12 may rest or which may be secured to the laser welding apparatus 100. As illustrated, a first mount 20, a second mount 30 and a third mount 40 may be secured to or may be integral with the base 12. One or more of the mounts 20, 30, 40 are configured to secure one or more of the first mandrel 22, the second mandrel 32 and/or the third mandrel 42 at fixed positions relative to one another and/or the base 12.

The first mount 20, the second mount 30 and the third mount 40 may be integral with the base 12 or may be secured to a surface such as for example an upper surface 16 of the base 12. In one aspect, one or more of the mounts 20, 30, 40 may be formed within the base 12. In another aspect, one or more of the mounts 20, 30, 40 may extend upward from an upper surface 16 of the base 12. Mounts 20, 30, 40 may be secured to base 12 with bolts 50 or may otherwise be secured to the base such as by adhesives or welding for example as will be recognized by those skilled in the art. The base 12 may define an orifice 18 extending through the base between the lower surface 14 and the upper surface 16. Alternatively, the base may define a cavity 19 formed in the upper surface 16 of the base 12.

Each of mandrels 22, 32, 42 is generally configured to be received through a passage 222, 224, 226 in one of the mono-tubular stents 212, 214, 216. Mandrels 22, 32, 42 are typically configured in the form of rods having a generally circular cross-section although other configurations may be utilized as will be recognized by those skilled in the art. Typically, mandrels 22, 32, 42 are generally illustrated as linear however, the mandrels may have one or more curves or bends as will be recognized by those skilled in the art upon review of the present disclosure. Mandrels 22, 32, 42 are oriented such that there longitudinal axes are generally aligned with a central point 300 to permit the alignment and securing of aspects of mono-tubular stents 212, 214, 216 adjacent to one another. In one aspect, the central point 300 may be aligned with the central axis of a circular orifice 18 or cavity 19. First mandrel 22, second mandrel 32, and third mandrel 42 are typically secured to the base 12 to allow the first tip 28, second tip 38 and third tip 49 to be positioned adjacent to one another. Depending on the embodiment, tips 28, 38, 48 may be blunt, rounded or in the form of a point or edge or otherwise configured as will be recognized by those skilled in the art. In certain aspects, first mandrel 22, second mandrel 32, and third mandrel 42 may be secured to the base 12 to allow the first tip 28, second tip 38 and third tip 49 of the respective mandrels 22, 32, 42 to be abutted against one another. A first knob 62, second knob 72 and a third knob 82 may be positioned at the respective first outer end of the first mandrel 22, the second outer end of the second mandrel 32, and the third outer end of the third mandrel 42, respectively. Knobs 62, 72, 82 may include ridges or cavities to accept tools to simplify the manipulation of the mandrels 22, 32, 42 by a user.

As is generally illustrated for exemplary purposes, first mandrel 22, second mandrel 32, and third mandrel 42 may be received through a first mandrel receiving passage 66, a second mandrel receiving passage 76 and a third mandrel receiving passage 86, respectively. The first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86 can be defined in base 12 and/or by first mount 20, second mount 30 and third mount 40, respectively. Typically, the mandrel receiving passage 66, 76, 86 will fix the angular position of each of first mandrel 22, second mandrel 32, and third mandrel 42 relative to the base 12. The first mandrel 22, second mandrel 32, and third mandrel 42 may be relatively sized to slide through first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86, respectively. In one aspect, the base 12 may further define a first set screw lumen 25, a second set screw lumen 35 and a third set screw lumen 45 in communication with first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86, respectively. A first set screw 24, a second set screw 34 and a third set screw 44 may be threadably engaged within first set screw lumen 25, second set screw lumen 35 and third set screw lumen 45 to lock the first mandrel 22, second mandrel 32 and third mandrel 42 at desired positions. To lock a mandrel 22, 32, 42 at a desired position, a set screw 24, 34, 44 may be rotated relative to the base within the set screw lumen 25, 35, 45 to bias an end of the set screw 24, 34, 44 against the mandrel 22, 32, 42. In another aspect, first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86 may include first internal thread 65, second internal thread 75, and third internal thread 85, respectively. When the mandrel receiving passage 66, 76, 86 include internal thread 65, 75, 85, first mandrel 22, second mandrel 32, and third mandrel 42 may include first external thread 64, second external thread 74, and third external thread 84 respectively, to engage internal thread 65, 75, 85. When external thread 64, 74, 84 are engaged with external thread 65, 75, 85, the respective mandrel 22, 32, 42 may be longitudinally positioned relative to base 12 by rotating the mandrel 22, 32, 42.

FIGS. 3A to 3D illustrate similar exemplary embodiments of a fixture 10 in accordance with one or more of the present inventions. As illustrated, the base 12 is a modular component including a first mount 20, a second mount 30 and a third mount 40 extending from an upper surface 16 of base 12. The first mount 20, second, mount 30 and third mount 40 are secured to the upper surface 16 of the base 12 with bolts 50 which extend through the mounts 20, 30, 40 into base 12. As illustrated, the first mount 20, second mount 30 and third mount 40 include a first channel 26, a second channel 36 and a third channel 46, respectively on an upper surface of the mount. The first channel 26, second channel 36, and third channel 46 extend in a substantially parallel orientation with the first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86, respectively. The first channel 26, second channel 36, and third channel 46 may include a first biasing member 126, a second biasing member 136 and a third biasing member 138 which may be in contact with a first mandrel 22, a second mandrel 32 and a third mandrel 42, respectively. The biasing members 126, 136, 146 may inhibit unwanted movement of associated mandrels 22, 32, 42 within mounts 20, 30, 40. As illustrated in FIGS. 3A to 3D, the base 12 includes a lower surface of base 12 is flat to permit base 12 to be stably rested on a flat work surface such as work surface 106, shown in FIG. 1. Further, the base 12 defines an orifice 18 extending through the base 12 between the lower surface 14 and the upper surface 16. The orifice 18 may permit the welding of mono-tubular stents 212, 214, 216 when either the lower surface 14 or the upper surface is placed adjacent to a work surface 106 of a laser welding apparatus 100. Thus, the orifice 18 may permit the fixture 10 mono-tubular stents 212, 214, 216 to be secured to one another on opposing sides without requiring that the removal of the mono-tubular stents 212, 214, 216 from their respective mandrels 20, 30, 40.

Mandrels 22, 32, 42 are illustrated in FIGS. 3A to 3D as linear rods. The first mandrel 22, second mandrel 32, and third mandrel 42 are received through a first mandrel receiving passage 66, a second mandrel receiving passage 76 and a third mandrel receiving passage 86, respectively. The mandrels 22, 32, 42 are illustrated as slidably positioned within mandrel receiving passage 66, 76, 86. Fixture 10 of FIGS. 3A to 3D uses set screws 24, 34, 44 to lock the mandrels in desired positions. Mandrels 22, 32, 42 shown as oriented to align their longitudinal axes with central point 300. The central point 300 is illustrated as generally aligned with the central axis of orifice 18. First mandrel 22, second mandrel 32, and third mandrel 42 are secured to the base 12 to allow the first tip 28, second tip 38 and third tip 49 to be positioned adjacent to one another. If desired by a user of the illustrated embodiment, first mandrel 22, second mandrel 32, and third mandrel 42 may be positioned with the first tip 28, second tip 38 and third tip 49 abutted against one another. Accordingly, aspects of mono-tubular stent 212, 214, 216 positioned about the mandrels 22, 32, 42 may be properly positioned for laser welding or other techniques used to secure such aspects.

FIGS. 4A to 4D illustrate another set of similar exemplary embodiments of a fixture 10 in accordance with the present inventions. As illustrated, the base 12 is a unitary component without distinct mounts 20, 30, 40. As illustrated, the base 12 includes a lower surface of base 12 is flat to permit base 12 to be stably rested on a flat work surface such as work surface 106, shown in FIG. 1. Further, the base 12 defines an orifice 18 extending through the base 12 between the lower surface 14 and the upper surface 16. Similar to the embodiments illustrated in FIGS. 3A to 3B, the orifice 18 may permit the welding of mono-tubular stents 212, 214, 216 when either the lower surface 14 or the upper surface is placed adjacent to a work surface 106 of a laser welding apparatus 100. In addition, the base 12 of FIGS. 4A to 4D include a first lateral passage 60, a second lateral passage 70, and a third lateral passage 80. First lateral passage 60, second lateral passage 70, and third lateral passage 80 extend about the longitudinal axis extending from the third mandrel receiving passage 86, the first mandrel receiving passage 66, and the second mandrel receiving passage 76, respectively. The first lateral passage 60, second lateral passage 70, and third lateral passage 80 may permit the passage of a laser apparatus 100 or laser beam 110. Accordingly, another portion of the mono-tubular stents 212, 214, 216 may be welded without removal of the mono-tubular stents 212, 214, 216 from fixture 10. The first mandrel receiving passage 66, a second mandrel receiving passage 76 and a third mandrel receiving passage 86 are radially spaced about a central point 300 positioned within the approximate center of the orifice 18. For exemplary purposes, the mandrel receiving passage 66, 76, 86 are oriented with their longitudinal axis at approximately 120 degree angles from one another for exemplary purposes.

The embodiment of fixture 10 illustrated in FIGS. 4A to 4D includes internal thread 65, 75, 85 positioned within first mandrel receiving passage 66, second mandrel receiving passage 76 and third mandrel receiving passage 86 to lock the mandrels in desired positions. Accordingly, the mandrels 22, 32, 42 are illustrated as linear rods having external thread 64, 74, 84 received by internal thread 65, 75, 85. Accordingly, first mandrel 22, second mandrel 32, and third mandrel 42 are positioned relative to the base by rotation. In one aspect, the first mandrel 22, second mandrel 32, and third mandrel 42 may be rotated by rotation of a first knob 62, a second knob 72 and a third knob 82 secured to the outer end of the respective mandrel 22, 32, 42. Mandrels 22, 32, 42 are again secured to the base 12 to allow the first tip 28, second tip 38 and third tip 49 to be positioned adjacent to one another. If desired by a user of the illustrated embodiment, first mandrel 22, second mandrel 32, and third mandrel 42 may be positioned with the first tip 28, second tip 38 and third tip 49 abutted against one another. Accordingly, aspects of mono-tubular stent 212, 214, 216 positioned about the mandrels 22, 32, 42 may be properly positioned for laser welding or other techniques used to secure such aspects.

FIGS. 5A to 5C illustrate yet another exemplary embodiment of a fixture 10 in accordance with the present inventions. The fixture 10 as illustrated in FIGS. 5A to 5C is generally similar to the embodiment of fixture 10 illustrated in FIGS. 3A to 3D with the addition of a platform 92 upon which the base 12 is secured. The platform 92 defines an upper platform surface 96 which is configured to stably receive the base 12. As particularly illustrated, the upper platform surface 96 is configured to abut a lower surface 14 of the base 12. The upper platform surface 96 may be configured to receive an upper surface 16 of the base 12. A plurality of detents 95, 97, 99 may be provided on the upper platform surface 96 to maintain the base 12 in a desired position on the upper platform surface 96. The detents 95, 97, 99 may extend upward from the upper platform surface 96. In one aspect, the detents 95, 97, 99 are relatively positioned to abut a peripheral portion of the base 12 to stably secure the base 12 to the platform 92. As particularly illustrated, detents 95, 97, 99 may permit the base 12 to be secured to the platform 92 in one of three relative positions. The relative positions may be adjusted by lifting the base 12 from in between detents 95, 97, 99 and rotating the base 12 in 120 degree relative to the platform 92 before repositioning the base 12 between detents 95, 97, 99. In addition, a focusing aid 93 may be provided and positioned adjacent to the tips 28, 38, 48 of mandrels 22, 32, 42 to aid in the positioning of the laser apparatus 100 relative to fixture 10. The focusing aid 93 may be in the form of a rod extending upward from the platform 92 or, in other aspects, from the base 12 to position an upper surface 97 of the rod adjacent to the tips 28, 38, 48 of mandrels 22, 32, 42. Such a focusing aid 93 may assist in focusing the optics by better facilitating a determination of the focal position of the laser relative to the workpiece.

A fixture 10 in accordance with the present inventions may be used to manufacture a bifurcated stent 210 from mono-tubular stents 212, 214, 216 using a range of techniques as will be recognized by those skilled in the art upon review of the present disclosure. Generally, the each mono-tubular stent 212, 214, 216 may be made by laser cutting, water-jet cutting, or chemical etching of a preformed tube or a sheet to be rolled into a tube; by molding; by weaving; or by other methods that will be recognized by those skilled in the art. In one exemplary method, the mono-tubular stent 212, 214, 216 can be cut from a tube. In this method, the mono-tubular stent 212, 214, 216 is generally formed by removal of material from the cylindrical wall of the tube. The material remaining typically forms the mono-tubular stent 212, 214, 216. Exemplary apparatus and methods for manufacturing mono-tubular stents 212, 214, 216 in accordance with the present inventions are disclosed in U.S. Pat. Nos. 5,324,913, 5,852,277 and 6,1214,653, the disclosures of which are hereby incorporated by reference. After cutting, the cut mono-tubular stent 212, 214, 216 is typically cleaned to remove the laser scale. This cleaning may be accomplished using chemicals and methods that are known to those skilled in the art. The mono-tubular stents 212, 214, 216 may then be heat treated in an annealing process to 1850 degrees Fahrenheit followed by cooling with nitrogen to a temperature of about 100 degrees Fahrenheit before removing from the furnace. In one aspect, three mono-tubular stents 212, 214, 216 may be laser welded together. To relatively position mono-tubular stents 212, 214, 216, each of the mono-tubular stents 212, 214, 216 is fitted over a mandrel 22, 32, 42 of a fixture 10. The first tip 28, second tip 38 and third tip 38 of the respective mandrels 22, 32, 42 are then secured in a generally radial orientation about central point 300. The mono-tubular stents 212, 214, 216 are positioned on the mandrels 22, 32, 42 such that their proximal ends are positioned relative to one another in a manner to permit the laser welding of aspects of proximal ends to one another. As illustrated for exemplary purposes in FIG. 6, the aspects to be welded together include terminal connectors 262, 264, 266. The terminal connectors 262, 264, 266 may then be laser welded at their first surfaces 272, 274, 276 and/or second surfaces 282, 284, 286. Once welded or otherwise secured to one another, the mandrels 22, 32, 42 may be released from the base and removed from their respective passages within the mono-tubular stents 212, 214, 216 to leave the substantially completed bifurcated stent 210.

Although illustrated and described herein with reference to certain specific embodiments, the present inventions is nevertheless not intended to be limited to the details provided in the foregoing description. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.

Claims

1. An apparatus for manufacture of a bifurcated stent, comprising:

a base including a first mount, a second mount, and a third mount, the base defining a lower surface adapted to be stably received on a work surface,
a first mandrel defining a first tip, the first mandrel secured to the first mount at one of a plurality of first desired positions along the first mandrel;
a second mandrel defining a second tip, the second mandrel secured to the second mount at one of a plurality of second desired positions along the second mandrel;
a third mandrel defining a third tip, the third mandrel secured to the third mount at one of a plurality of third desired positions along the third mandrel;
each of the first mandrel, the second mandrel and the third mandrel being securable in at least one position that places the first tip, the second tip, and the third tip adjacent to one another.

2. An apparatus, as in claim 1, further comprising the first mount defining at least a first mandrel receiving passage, the second mount defining at least a second mandrel receiving passage and the third mount defining at least a third mandrel receiving passage, the first mandrel receiving passage defining a first longitudinal axis, the second mandrel receiving passage defining a second longitudinal axis and the third mandrel receiving passage defining a third longitudinal axis, the first mandrel slidably positioned within the first mandrel receiving passage, the second mandrel slidably received within the second mandrel receiving passage, and the third mandrel slidably received in the third mandrel receiving passage.

3. An apparatus, as in claim 2, further comprising a first set screw lumen intersecting the first mandrel receiving passage and a first set screw threadably received within the first set screw lumen to secure the first mandrel relative to the base; a second set screw lumen intersecting the second mandrel receiving passage and a second set screw threadably received within the second set screw lumen to secure the second mandrel relative to the base; and a third set screw lumen intersecting the third mandrel receiving passage and a third set screw threadably received within the third set screw lumen to secure the third mandrel relative to the base.

4. An apparatus, as in claim 2, further comprising the first longitudinal axis, the second longitudinal axis, and the third longitudinal axis intersecting at a central point.

5. An apparatus, as in claim 2, further comprising:

the first mandrel receiving passage including a first internal thread and the first mandrel including a first external thread, the first external thread of the first mandrel threadably received within the first internal thread of the first mandrel receiving passage to permit the rotational positioning of the first mandrel within the first mandrel receiving passage;
the second mandrel receiving passage including a second internal thread and the second mandrel including a second external thread, the second external thread of the second mandrel threadably received within the second internal thread of the second mandrel receiving passage to permit the rotational positioning of the second mandrel within the second mandrel receiving passage; and
the third mandrel receiving passage including a third internal thread and the third mandrel including a third external thread, the third external thread of the third mandrel threadably received within the third internal thread of the third mandrel receiving passage to permit the rotational positioning of the third mandrel within the third mandrel receiving passage.

6. An apparatus, as in claim 5, further comprising a first knob secured to a first outer end of the first mandrel, a second knob secured to a second outer end of the second mandrel, and a third knob secured to a third outer end of the third mandrel.

7. An apparatus, as in claim 1, further comprising the base defining an orifice positioned about a central point and extending through the base between the lower surface and an upper surface.

8. An apparatus, as in claim 1, further comprising the base defining a cavity positioned about a central point and extending into the upper surface of the base.

Patent History
Publication number: 20070266760
Type: Application
Filed: May 17, 2006
Publication Date: Nov 22, 2007
Inventors: Gladwin S. Das (St. Paul, MN), Gary Oberg (Darwin, MN)
Application Number: 11/436,734
Classifications
Current U.S. Class: With Tool Carrier (e.g., Press Frame) (72/455)
International Classification: B21J 13/04 (20060101);