Patent Application
20240130873
The disclosure is directed to a mandrel for forming a stent having anti-migration features. More particularly, the disclosure is directed to an adjustable mandrel for forming a stent having anti-migration features.
A stent may be configured to be positioned in a body lumen for a variety of medical applications. For example, a stent may be used to treat a stenosis in a blood vessel, used to maintain a fluid opening or pathway in the vascular, urinary, biliary, tracheobronchial, esophageal or renal tracts, or to position a device such as an artificial valve or filter within a body lumen, in some instances. In some cases, a stent may include anti-migration features in order to help anchor the stent in place in whichever body lumen the stent is placed. In some instances, forming these ant-migration features may be difficult to do accurately and repeatedly.
The disclosure is directed to several alternative designs, materials and methods of manufacturing medical device structures and assemblies, and uses thereof. An example device for manufacturing a medical device structure is a mandrel to form an anti-migratory stent. The mandrel includes a mandrel body having a bore extending within the mandrel body as well as one or more apertures that are radially disposed about the mandrel body. One or more movable pins are outwardly extendable from the one or more apertures. The mandrel also includes an actuation element engagable with the bore extending within the mandrel body and including a tapered surface configured to engage the one or more movable pins, the actuation element being actuatable relative to the mandrel body such that the tapered surface supports the one or more movable pins extended from the one or more apertures.
Alternatively or additionally to any embodiment above, the mandrel body may include a first stent shaping segment having a first diameter, a second stent shaping segment having a second diameter less than the first diameter, and a tapered segment disposed between the first stent shaping segment and the second stent shaping segment.
Alternatively or additionally to any embodiment above, the mandrel may further include a third stent shaping segment releasably securable to the second stent shaping segment, the third stent shaping segment having a third diameter greater than the second diameter.
Alternatively or additionally to any embodiment above, the one or more movable pins may include a plurality of pins, and the one or more apertures may include a plurality of apertures such that there is a pin disposable within each of the plurality of apertures.
Alternatively or additionally to any embodiment above, at least some of the plurality of pins have equal lengths.
Alternatively or additionally to any embodiment above, the plurality of apertures are equally spaced circumferentially about the tapered segment.
Alternatively or additionally to any embodiment above, the corresponding apertures extend through the tapered segment and are configured to enable the pins to extend orthogonally to a tapered surface of the tapered segment.
Alternatively or additionally to any embodiment above, the corresponding apertures extend through the tapered segment and are configured to enable the pins to extend at varying angles relative to a tapered surface of the tapered segment.
Alternatively or additionally to any embodiment above, an end of each of the one or more movable pins includes a recessed slot configured to accommodate a wire of a stent being shaped on the mandrel.
Another example device is a mandrel for forming a stent with a tapered outer profile and anti-migration features, the mandrel including a mandrel body having a first stent shaping segment having a first diameter and a first threaded aperture extending within the first stent shaping segment, a second stent shaping segment having a second diameter less than the first diameter and a second threaded aperture extending within the second stent shaping segment and a tapered segment disposed between the first stent shaping segment and the second stent shaping segment, the tapered segment including a tapered surface. A plurality of apertures extend through the tapered surface. The mandrel includes a plurality of movable pins, each of the plurality of movable pins outwardly extendable from one of the plurality of apertures, the plurality of movable pins being configured to form the anti-migration features in the stent. The mandrel includes a mandrel cap that is releasably securable to the second stent shaping segment and that includes a third stent shaping segment having a third diameter greater than the second diameter. An actuation element includes a tapered end that is configured to engage the plurality of movable pins and a threaded body that is configured to threadedly engage the first threaded aperture. Rotating the actuation element causes the actuation element to advance into the first stent shaping segment such that the tapered end drives the plurality of movable pins in an outward direction.
Alternatively or additionally to any embodiment above, the third diameter is equal to the first diameter.
Alternatively or additionally to any embodiment above, at least some of the plurality of pins have equal lengths.
Alternatively or additionally to any embodiment above, at least some of the plurality of pins have differing lengths.
Alternatively or additionally to any embodiment above, an end of each of the plurality of movable pins includes a recessed slot configured to accommodate a wire of a stent being shaped on the mandrel.
Alternatively or additionally to any embodiment above, the plurality of apertures extend through the tapered segment and are configured to enable the pins to extend orthogonally to a tapered surface of the tapered segment.
Alternatively or additionally to any embodiment above, the plurality of apertures extend through the tapered segment and are configured to enable the pins to extend at varying angles relative to a tapered surface of the tapered segment.
An example method may be found in a method of manufacturing a stent having anti-migration features. A knitted stent blank may be disposed in position over a mandrel that includes a tapered outer surface and one or more anti-migration feature forming elements. A wire of the knitted stent blank may be engaged with the one or more anti-migration feature forming elements, and the woven stent blank may be annealed while disposed on the mandrel to form a shaped stent with the anti-migration feature. The one or more anti-migration feature forming elements may be disengaged in order to remove the shaped stent from the mandrel.
Alternatively or additionally to any embodiment above, the one or more anti-migration feature forming elements include pins that are configured to be driven in a radially outward direction relative to a central longitudinal axis of the mandrel, and engaging the wire with the one or more anti-migration feature forming elements includes driving the pins in the radially outward direction relative to the central longitudinal axis of the mandrel.
Alternatively or additionally to any embodiment above, disengaging the one or more anti-migration feature forming elements includes permitting the pins to move in a radially inward direction relative to the central longitudinal axis of the mandrel.
Alternatively or additionally to any embodiment above, disposing the knitted stent blank in position over the mandrel includes stretching the knitted stent blank over the mandrel and allowing the knitted stent blank to conform to the tapered outer surface of the mandrel.
The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the aspects of the disclosure.
The aspects of the disclosure may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
While the aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
Definitions of certain terms are provided below and shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
Although some suitable dimensions, ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed.
As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include or otherwise refer to singular as well as plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed to include “and/or,” unless the content clearly dictates otherwise.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.
As can be seen, the mandrel 10 includes a mandrel body 12, a mandrel cap 14, an actuation element 16 and a plurality of anti-migration feature forming pins 18.
The mandrel body 12, shown in
In some cases, particularly if the first stent shaping segment 20 and the second stent shaping segment 22 have a similar or identical outer diameter, the tapered surface 26 may itself not be tapered, but may instead have a constant outer diameter. In some instances, at least some of the plurality of apertures 27 may have a major dimension that is orthogonal to the tapered surface 26. In some cases, at least some of the plurality of apertures 27 may have a major dimension that extends at an acute angle relative to the tapered surface 26. It will be appreciated that in some cases, some of the plurality of apertures 27 may extend at different angles relative to the tapered surface 26. As shown, the plurality of apertures 27 may be considered as being radially aligned in a ring that extends around the tapered segment 24. In some cases, it will be appreciated that some of the plurality of apertures 27 may be axially displaced relative to others of the plurality of apertures 27. In other words, some of the plurality of apertures 27 may form a first ring around the tapered segment 24 while others of the plurality of apertures 27 may form a second ring around that tapered segment 24 that is axially displaced from the first ring around the tapered segment 24.
In some cases, at least some of the plurality of apertures 27 may extend linearly through the tapered segment 24 such that each corresponding pin 18 extends through the aperture 27 orthogonally to the tapered surface 26. In some cases, at least some of the apertures 27 may have a curved or helical shape, such that as the corresponding pin 18, which may have a complementary curved or helical shape, is extended out of the aperture 27, the pin 18 may rotate, and thus a distal end of the pin 18 (such as the pin end 62) may move radially as well as axially.
The actuation element 16 may be configured to extend into the bore of the mandrel body 12 from one end of the mandrel body 12 (e.g., the end of the mandrel body opposite to the mandrel cap 14) to selectively engage and actuate the pins 18 within the apertures 27. For example, the actuation element 16, shown in
As seen in
While the pin end 62 is illustrated as a curved profile and being no larger in dimension than the pin body 60, in some cases it is contemplated that the pin end 62 may extend laterally beyond the pin body 60 and form an arcuate surface. In some cases, for example, the arcuate surface of each of the pin ends 62 may align end to end, and essentially form a raised ring extending around the mandrel 10. The individual arcuate surfaces of each of the pin ends 62 may be driven outward by extending the actuation element 16 into the mandrel body 12 by rotating the actuation element 16 in a first rotational direction in order to form a raised ring anti-migration feature in the stent. Rotating the actuation element 16 in a second, opposing rotational direction, allows the pins 18 to retract, and allow removal of the stent from the mandrel 10.
It will be appreciated that the relative dimensions of the anti-migration features 78 and the anti-migration features 78a may be a function of the ultimate end-use of the knitted stent 70 (or 70a). Relatively larger anti-migration features 78, 78a may be useful in situations where the knitted stent 70 (or 70a) will be placed in anatomical locations where the knitted stent 70 (or 70a) may be subjected to relatively stronger migration forces and/or anatomical locations where the dimensions of the patient's anatomy are more variable. Relatively smaller anti-migration features 78, 78a may be useful in situations where the knitted stent 70 (or 70a) may be subjected to relatively weaker migration forces and/or anatomical locations where the dimensions of the patient's anatomy are less variable. In some cases, the overall dimensions of the knitted stent 70 (or 70a) may play a part as well. In some cases, for example, a larger diameter knitted stent 70 (or 70a) may have relatively larger anti-migration features 78, 78a while a smaller diameter knitted stent 70 (or 70a) may have relatively smaller anti-migration features 78, 78a.
The one or more anti-migration feature forming elements (such as but not limited to the pins 18) may be engaged, as noted at block 94, in order to provide a desired shape prior to annealing, as indicated at block 96. In some cases, the one or more anti-migration feature forming elements are pins that are configured to be driven in a radially outward direction relative to the outer surface of the mandrel, and engaging the one or more anti-migration feature forming elements includes driving the pins in radially outward direction relative to the mandrel to urge the wire(s) or filament(s) engaged with the end of each of the pins in a radially outward direction relative to the knitted tubular structure of the stent. The mandrel and the stent thereon, with the anti-migration features formed, may then be subjected to an annealing or shape setting process. As seen at block 98, after the annealing or shape setting process, the one or more anti-migration feature forming elements may be disengaged in order to remove the shaped stent from the mandrel. In some cases, disengaging the one or more anti-migration feature forming elements comprises permitting the pins to move in an inward direction relative to the mandrel.
In some cases, a constant diameter metallic knitted stent blank may be positioned over a mandrel having a tapered outer surface and one or more anti-migration feature forming elements, as generally indicated at block 102. The mandrel may be the mandrel 10, for example. In some cases, disposing a constant diameter metallic knitted stent blank in position over a mandrel includes stretching the constant diameter metallic knitted stent blank over the mandrel and allowing the constant diameter metallic knitted stent blank to conform to the varied diameter outer surface of the mandrel, such conforming to the various constant diameter regions and/or tapered diameter regions of the mandrel.
The one or more anti-migration feature forming elements (such as but not limited to the pins 18) may be engaged, as noted at block 104, in order to provide a desired shape prior to annealing, as indicated at block 106. In some cases, the one or more anti-migration feature forming elements are pins that are configured to be driven in a radially outward direction relative to the outer surface of the mandrel, and engaging the one or more anti-migration feature forming elements includes driving the pins in radially outward direction relative to the mandrel to urge the wire(s) or filament(s) engaged with the end of each of the pins in a radially outward direction relative to the knitted tubular structure of the stent. The mandrel and the stent thereon, with the anti-migration features formed, may then be subjected to an annealing or shape setting process. As seen at block 108, after the annealing or shape setting process, the one or more anti-migration feature forming elements may be disengaged in order to remove the shaped stent from the mandrel. In some cases, disengaging the one or more anti-migration feature forming elements comprises permitting the pins to move in an inward direction relative to the mandrel.
In some cases, once the shaped metallic stent has been removed from the mandrel, a constant diameter biodegradable knitted stent blank may be positioned over a mandrel having a tapered outer surface and one or more anti-migration feature forming elements, as generally indicated at block 110. In some cases, disposing a constant diameter biodegradable knitted stent blank in position over a mandrel includes stretching the constant diameter biodegradable knitted stent blank over the mandrel and allowing the constant diameter biodegradable knitted stent blank to conform to the varied diameter outer surface of the mandrel, such conforming to the various constant diameter regions and/or tapered diameter regions of the mandrel. The one or more anti-migration feature forming elements may be engaged, as noted at block 112, in order to provide a desired shape prior to annealing, as indicated at block 114.
In some cases, the annealing process for the biodegradable knitted stent blank may involve lower temperatures than that used for the metallic knitted stent blank. The mandrel and the stent thereon, with the anti-migration features formed, may then be subjected to an annealing or shape setting process. As seen at block 116, after the annealing or shape setting process, the one or more anti-migration feature forming elements may be disengaged in order to remove the shaped biodegradable stent from the mandrel. In some cases, disengaging the one or more anti-migration feature forming elements comprises permitting the pins to move in an inward direction relative to the mandrel. In some cases, while not illustrated, the shaped biodegradable stent may be disposed about or within the shaped metallic stent.
In some embodiments, the knitted stent 70 may be formed from any desired material, such as a biocompatible material including biostable, bioabsorbable, biodegradable or bioerodible materials. For instance, the knitted stent 70 may be formed of a metallic material. Some suitable metallic materials include, but are not necessarily limited to, stainless steel, tantalum, tungsten, nickel-titanium alloys such as those possessing shape memory properties commonly referred to as nitinol, nickel-chromium alloys, nickel-chromium-iron alloys, cobalt-chromium-nickel alloys, or other suitable metals, or combinations or alloys thereof. In some cases, the mandrel 10 may be formed of a material that is thermally stable and does not materially expand at the temperatures used in annealing the knitted stent 70. In some cases, for example, the mandrel 10 may be formed of a metallic material such as stainless steel, titanium or a nickel-titanium alloy. In some cases, the mandrel 10 may be formed of a ceramic material
In some embodiments, the knitted stent 70 may include one or more metals. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material.
As alluded to herein, within the family of commercially available nickel-titanium or nitinol alloys, is a category designated “linear elastic” or “non-super-elastic” which, although may be similar in chemistry to conventional shape memory and super elastic varieties, may exhibit distinct and useful mechanical properties. Linear elastic and/or non-super-elastic nitinol may be distinguished from super elastic nitinol in that the linear elastic and/or non-super-elastic nitinol does not display a substantial “superelastic plateau” or “flag region” in its stress/strain curve like super elastic nitinol does. Instead, in the linear elastic and/or non-super-elastic nitinol, as recoverable strain increases, the stress continues to increase in a substantially linear, or a somewhat, but not necessarily entirely linear relationship until plastic deformation begins or at least in a relationship that is more linear that the super elastic plateau and/or flag region that may be seen with super elastic nitinol. Thus, for the purposes of this disclosure linear elastic and/or non-super-elastic nitinol may also be termed “substantially” linear elastic and/or non-super-elastic nitinol.
In some cases, linear elastic and/or non-super-elastic nitinol may also be distinguishable from super elastic nitinol in that linear elastic and/or non-super-elastic nitinol may accept up to about 2-5% strain while remaining substantially elastic (e.g., before plastically deforming) whereas super elastic nitinol may accept up to about 8% strain before plastically deforming. Both of these materials can be distinguished from other linear elastic materials such as stainless steel (that can also can be distinguished based on its composition), which may accept only about 0.2 to 0.44 percent strain before plastically deforming.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a large temperature range. For example, in some embodiments, there may be no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about −60 degrees Celsius (° C.) to about 120° C. in the linear elastic and/or non-super-elastic nickel-titanium alloy. The mechanical bending properties of such material may therefore be generally inert to the effect of temperature over this very broad range of temperature. In some embodiments, the mechanical bending properties of the linear elastic and/or non-super-elastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, for example, in that they do not display a super-elastic plateau and/or flag region. In other words, across a broad temperature range, the linear elastic and/or non-super-elastic nickel-titanium alloy maintains its linear elastic and/or non-super-elastic characteristics and/or properties.
In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, with the remainder being essentially titanium. In some embodiments, the composition is in the range of about 54 to about 57 weight percent nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy commercially available from Furukawa Techno Material Co. of Kanagawa, Japan. Some examples of nickel titanium alloys are disclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which are incorporated herein by reference. Other suitable materials may include ULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available from Toyota). In some other embodiments, a superelastic alloy, for example a superelastic nitinol can be used to achieve desired properties.
Those skilled in the art will recognize that aspects of the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope of the present disclosure as described in the appended claims.
This application is a continuation of U.S. patent application Ser. No. 16/046,174, filed Jul. 26, 2018, which claims priority to U.S. Provisional Application Ser. No. 62/537,761, filed Jul. 27, 2017, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62537761 | Jul 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16046174 | Jul 2018 | US |
| Child | 18403502 | US |
