Stents are medical devices commonly used to maintain patency of diseased body vessels, such as those of the vascular and gastrointestinal systems. Stents are often delivered via a minimally invasive procedure and thereafter expanded to contact and support the inner wall of the targeted vessel. In general, most stents include a tubular shaped support structure having a plurality of interstices or struts configured to facilitate compression and expansion of the stent.
Esophageal self-expandable metal stent placement is a common procedure used to palliate inoperable esophageal carcinoma, manage benign strictures, seal the esophagus after a perforation, and manage other issues. Stents have achieved positive results in the esophagus, but complications occasionally arise. For example, when a stent is used, migration of the stent is one of the most common complications, arising between about 4-36% of the time depending on certain factors. After a stent migrates, the stent may fail to serve its intended purpose and may cause additional detrimental effects. For example, migrated stents may cause chest pain, recurrent dysphagia, and even more serious effects such as intestinal obstruction. Further, a migrated stent may be difficult to retrieve from the body, particularly without using invasive procedures.
In light of this background, it would be advantageous to provide an improved stent having features for preventing stent migration without inhibiting the stent's primary purpose and without increasing the difficulty and invasiveness of removing the stent after a period of time.
One general aspect of the present disclosure is a method for installing a stent within a patient body. The method may include deploying the stent such that at least one opening of the stent is aligned with a tissue surface within a body of a patient. The method may further include manipulating a tissue portion through the at least one opening of the stent. The method may further include securing the tissue portion with respect to the opening of the stent to prevent migration of the stent.
Another general aspect of the present disclosure includes a stent. The stent may have a body including a plurality of struts, a covering extending to an end of the body, the end being a proximal end of a distal end, and an anchor secured to the end of the body, where the anchor includes an opening that is exposed with respect to the covering.
Another general aspect of the present disclosure includes a stent with a biodegradable portion. The stent may further include a second portion, where the biodegradable portion is secured to a proximal end or a distal end of the second portion. The stent may further include a stent covering that at least partially covers the second portion of the stent. The biodegradable portion may include at least one opening that is exposed with respect to the cover to facilitate tissue ingrowth when the stent is deployed against a tissue surface.
The embodiments of the present disclosure may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the present disclosure. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views and arrangements.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.
The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following detailed description. However, the embodiments of this invention are not limited to the embodiments illustrated in the drawings. It should be understood that the drawings are not to scale, and in certain instances details have been omitted which are not necessary for an understanding of the present invention, such as conventional fabrication and assembly.
As used in the specification, the terms proximal and distal should be understood as being in the terms of a physician delivering the medical device to a patient. Hence the term “distal” means the portion of the medical device that is farthest from the physician and the term “proximal” means the portion of the medical device that is nearest to the physician.
The stent is depicted as having struts 104 that are uncovered, but in other embodiments (and as described below), the struts 104 may be fully covered or partially covered. If the stent 102 is uncovered (as depicted), the uncovered struts 104 may contact tissue of the esophagus wall when the stent 102 is deployed. Over time (e.g., typically between 3-7 days), the tissue of the esophagus wall may form tissue ingrowth through and/or around the struts 104 so that the stent 102 becomes embedded in the wall of the esophagus. Advantageously, the embedded nature of the stent 102 may substantially prevent it from migrating. However, an uncovered stent may be difficult to remove, and thus it may not be ideal for all procedures.
As shown in
To solve this problem, the stent 102 may include one or more anchors 106, 112, 114. While many embodiments are contemplated, in some embodiments, the anchor 106 may be formed with a loop 108 of metal wire surrounding an opening 118 (and while a “loop” may be an oval, the term “loop” does not require any particular shape in this disclosure). The loop 108 of metal wire may be integral and continuous with at least one of the struts 104 shown in
In the depicted embodiment of
The stent 102 may also include a second anchor 112 and a third anchor 114 as depicted, and it is not limited to three anchors. Each of the anchors 106, 112, 114 may be formed with different dimensions (as shown) and/or different materials, but alternatively, at least two of them may be substantially identical. The anchors 106, 112, 114 may be configured for maximizing tissue ingrowth, and thus, it is contemplated that no additional method for enhancing the tissue ingrowth may be necessary beyond deployment of the stent 102. However, it may be advantageous to enhance tissue ingrowth using the method of engaging a tissue portion 206 described below with reference to
In the depicted embodiment, after the stent 102 is deployed to a suitable location within the esophagus 202, the manipulation of the tissue portion 206 is accomplished through use of an endoscope 302. In some embodiments, the endoscope 302 may include a gripping device (not shown) and/or may be coupled to a vacuum source 306 to provide a suction force on the tissue portion 206. The suction force may be used to force the tissue portion 206 away from the wall 204 of the esophagus 202 and through the opening 118 of the anchor 106.
For example, initially, the tissue portion 206 may be flush with the remainder of the wall 204 of the esophagus 202 prior to manipulation). Then, a cap 304 of the endoscope 302, which may have an opening 308 at a distal end 310 that communicates with a vacuum source 306, may be placed in a location such that it contacts or in close proximity to the tissue portion 206—and then can pull the tissue portion 206 through the opening 118 upon initiation of the vacuum source 306. If necessary, the distal end 310 of the endoscope may be moved with respect to the loop 108 to guide the tissue portion 206 through the opening 118, but in other embodiments, the vacuum source 306 alone may be sufficient.
Once the tissue portion 206 is pulled through the opening 118 of the anchor 106, a securement device may be used to retain the tissue portion 206 through the opening 118 of the anchor 106. The securement device may be any suitable device (e.g., a mechanical clip or other fastener, a band formed of rubber, a sewn seam of tissue, etc.). In the depicted embodiment, the securement device includes at least one band 312 formed of a material with a high elasticity and resilience. The band 312 may be formed of a natural rubber latex in some embodiments, but other materials are also contemplated (e.g., silicon, urethane, etc.).
The band 312 may be installed around the tissue portion 206 by the endoscope 302. For example, the band 312 may be ejected from the cap 304 while the tissue portion 206 is subjected to suction. The band 312 may be provided and installed by any suitable device or method. In some embodiments, the band 312 is installed around the tissue portion 206 by the endoscope cap 304, which may have a mechanism that disengages with the band 312 in a manner such that the band 312 is ejected or “fired” from the cap 304 to its depicted located around the tissue portion 206. For example, the endoscope 302 may include a trigger cord (not shown) at its proximal end that can be pulled to eject the band from the distal end 310 of the cap 304. In one non-limiting specific example, the endoscope 302 and cap 304 may be included in a device marketed as a 6 Shooter® Universal Saeed® Multi-Band Ligator sole by Cook® Medical. The device may be capable of ejecting any suitable number of bands 312 (e.g., 6 bands, for example). Alternatively, instead of using a cap 304 of an endoscope 302 to suction tissue before banding, a smaller tissue portion may be suctioned through the distal end of a catheter and then a band can be pushed off of the same catheter for securement.
In some embodiments, and as illustrated by
The biodegradable portion 430 of the stent 402 may be at least partially uncovered, and may be fully uncovered as shown in
Similar to as described above, the anchors 406 and/or the cells 436 of the biodegradable portion 430 may be uncovered such that they are exposed with respect to the covering 316, and thus such that they are capable of facilitating tissue ingrowth when engaged with a tissue surface. In other words, over time (e.g., typically between 3-7 days), the tissue of the esophagus wall (or other tissue surface) may form tissue ingrowth through and/or around the cells 436 and/or the anchors 406 such that the biodegradable portion 430, and therefore the stent 402 itself, are prevented from unintentional migration.
Over time, the biodegradable portion 430 may degrade within the patient body due to its biodegradable material composition. Advantageously, the biodegradable portion 430 may be weakened over a period of weeks, months, or even years, such that, when it is time for the stent 402 to be removed, the weakened biodegradable portion 430 may be broken and/or otherwise decoupled from the second portion 432. After a predetermined period of time, the second portion 432 may then be removed without substantial damage to the esophagus wall or other tissue within the body of the patient.
The biodegradable portion 430 may be “tuned” or configured for stent removal after a particular time period. For example, dimensions of the components of the biodegradable portion 430 (e.g., the thickness of the struts 434) and the specific materials used in their construction may be preselected based on the desired time between stent deployment and removal. In some embodiments, for example, the materials and dimensions of the biodegradable portion 430 may be selected and used such that the biodegradable portion 430 is ready to suitably facilitate removal of the stent 402 after approximately a week from the time of deployment and installation. In other embodiments, the biodegradable portion 430 may be constructed with dimensions and materials such that it retains suitable structural integrity to prevent stent migration for a much longer time period (e.g., up to 6 months, a year, or even longer). It is preferable for the biodegradable portion 430 to be constructed such that it will not completely degrade prior to when the stent 402 will be removed from the body.
Optionally, the biodegradable portion 430 may include a selected failure point 438, where the biodegradable portion 430 is designed to break at the failure point 438 as the stent 402 is removed. The failure point 438 may be the point of attachment between the biodegrade portion 430 and the second portion 432, but other locations are also possible. The failure point 438 may be constructed using dimensions and/or materials such that, at least after a period of biodegradation with the patient, the failure point 438 will be the first location to fracture during stent removal. For example, the failure point 438 may have one or more strands or connectors 440 that have a thickness less than a thickness of the struts 434, a material that degrades faster than the material of the struts 434, or a combination of the two. Advantageously, the failure point 438 may ensure the stent 402 can be cleanly removed without leaving undesirable portions of the stent 402 within the body without creating pointed or jagged edges that may damage body tissue during or after stent removal.
When the biodegradable portion 430 includes the failure point 438, it is contemplated that the remainder of the biodegradable portion 430 may be formed of materials that do not substantially degrade within the patient body. However, it may still be advantageous for the remainder of the biodegradable portion 430 to degrade since it may be left within the patient body after stent removal. Thus, after a period of time, the biodegradable portion 430 may completely degrade, advantageously leaving the patient without an artificial device at the treated area.
In some embodiments, instead of (or in addition to) the inclusion of a biodegradable failure point as described above, the biodegradable portion 430 may be connected to the second portion 432 by another suitable device that is capable of releasing the biodegradable portion 430 from the second portion 432 such that the second portion 432 of the stent 402 can be removed from the patient. For example, a wire or other connector may secure the biodegradable portion 430 to the second portion 432, and the wire or other connector may be cut and/or pulled from the stent 402 by a medical professional during a removal procedure. Additionally or alternatively, a connector may be used that may be weakened and/or fracture by the application of RF energy, the application of an electrical current (e.g., D.C. current), the application of a chemical selected to dissolve the material of the connector, etc.
The figures and disclosure are intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in the art. All such variations and alternatives are intended to be encompassed within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the attached claims.
The present application claims the benefit of the filing date under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/629,332, filed Feb. 12, 2018, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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62629332 | Feb 2018 | US |