Tissue anchors for purse-string closure of perforations

Medical devices for attaching suture to tissue and that provides reliable and complete closure of perforations and increases the versatility of the device for various other procedures. Embodiments of the medicals devices include a tissue anchor having a crossbar with opposing ends and structure for slidably receiving a suture.

FIELD

The present invention relates generally to tissue anchors for connecting a suture to tissue, such are for using tissue anchors and suture to close perforations in tissue.

BACKGROUND

Perforations in bodily walls may be naturally occurring, or formed intentionally or unintentionally. In order to permanently close these perforations and allow the tissue to properly heal, numerous medical devices and methods have been developed employing sutures, adhesives, clips, staples and the like. One class of such devices is commonly referred to as tissue anchors (T-anchors) or visceral anchors. An exemplary tissue anchor is disclosed in U.S. Pat. No. 5,123,914, the entire contents of which are incorporated by reference herein. Such tissue anchors have been very successful in medical procedures requiring tissue wall mobilization or wall apposition.

Tissue anchors have also been successfully used in closing perforations, but are not without their drawbacks. For example, when a series of anchors are placed around a perforation, all of the individual sutures connected to the anchors must be collected and connected together. It can often be difficult to properly tension each of the individual sutures to ensure proper approximation of the tissue around the perforation and complete closure thereof. This is especially critical within the gastrointestinal tract, where the travel of bacteria laden fluids outside of the tract may cause unwanted and sometimes deadly infection.

BRIEF SUMMARY

The present invention provides medical devices for attaching suture to tissue and that provides reliable and complete closure of perforations and increases the versatility of the device for various other procedures. One embodiment of a tissue anchor for connecting a suture to tissue, constructed in accordance with the teachings of the present invention, generally comprises a crossbar and a strand. The crossbar has first and second opposing ends and defines a longitudinal axis. The crossbar is defined by a tubular wall having an aperture between the first and second ends. The strand has first and second opposing ends connected to the first and second opposing ends of the crossbar, respectively. The strand makes a revolution to define a loop. The strand and its loop project through the aperture and away from the longitudinal axis. The loop is sized to slidably receive the suture therethrough.

According to more detailed aspects of this embodiment of the tissue anchor, the strand has a diameter less than about 50% of a diameter of the crossbar. The strand preferably has a diameter in the range of about 0.2 mm to about 0.35 mm, while the crossbar has a diameter in the range of about 0.5 mm to about 1.1 mm. The loop has an apex located about 0.35 mm or greater away from the crossbar. The loop defines a cross-point where the ends of the strand cross each other, and the cross-point is preferably positioned radially outside the outer surface of the crossbar. The strand is flexible, and the aperture is sized to permit the loop to travel longitudinally along the strand. The aperture preferably extends a longitudinal distance in the range of about 0.4 mm to about 3.0 mm, while the crossbar typically has a length in the range of about 3.0 mm to about 10.0 mm. The strand may be a metal wire, and is preferably coated with a low-friction material.

Another embodiment of a tissue anchor for connecting a suture to tissue, constructed in accordance with the teachings of the present invention, generally comprises a crossbar and a strand. The crossbar has first and second opposing ends and defines a longitudinal axis. The cross bar is defined by a tubular wall having first and second apertures between the first and second ends, the first and second apertures being longitudinally spaced apart. A flexible suture has first and second opposing ends connected to the first and second opposing ends of the crossbar, respectively. The suture extends through the first and second apertures and projects away from the crossbar between the first and second apertures to define a loop between the suture and the crossbar.

Yet another embodiment of a tissue anchor for connecting a suture to tissue, constructed in accordance with the teachings of the present invention, generally comprises a crossbar and a flange. The crossbar has first and second opposing ends and defines a longitudinal axis. The flange is connected to the crossbar between the first and second ends and extends away from the longitudinal axis. The flange has a thickness less than a diameter of the crossbar. The flange defines a hole sized to receive the suture therein. According to more detailed aspects of this embodiment of the tissue anchor, an outer end surface of the flange follows a curved shape. Preferably, the crossbar and flange are unitarily and integrally formed. The crossbar and flange are optionally molded from a resorbable material.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the figures,FIGS. 1-2depict a tissue anchor20constructed in accordance with the teachings of the present invention. The anchor20is utilized to connect a suture22to tissue, such as for closing a perforation10in a bodily wall12(see, e.g.,FIGS. 6 to 9) or for use in other procedures. The anchor20generally includes a crossbar24having opposing ends26and28and defining a longitudinal axis14. The crossbar24is preferably elongated, but may take any form suitable for connecting the suture22to the bodily wall12. A strand30is connected to the crossbar24and is configured to form a loop32. As best seen inFIG. 2, the crossbar24is constructed of a cannula having a tubular wall34defining a lumen36. An elongated aperture38is formed in the tubular wall34, and the strand30passes through the aperture38. The ends of strand30are secured within the lumen36of the cannula by welds44. It will be recognized by those skilled in the art that the strand30may be secured to the crossbar24using any now known or hereinafter developed attachment means, including mechanical fasteners, adhesives or various welding or soldering techniques. Similarly, the strand30may have sufficient rigidity such that its ends do not need to be directly attached to the crossbar, as the formation of loop32projecting through the aperture38can be enough to retain the strand30within the crossbar24, and/or the ends of the strand30may simply be bent or otherwise deformed to keep them within the crossbar24and prevent them from passing through the aperture38.

The strand30is preferably formed from a metal wire, including single filament and multi-filament wires, and wound and braided wires, although the strand30can have other constructions such as suture material, plastic strings, rope and the like. As best seen inFIG. 1, the strand30is structured to include a revolution thereby defining a loop32through which the suture22passes. The loop32is positioned longitudinally in-line with the elongated aperture38so that it projects through the aperture38and away from the longitudinal axis14. Accordingly, it will be seen that the strand30and its loop32are flexible and may adjust its shape and orientation based on how the suture22is being tensioned. The size of the elongated aperture38and the flexibility of the strand30allow the loop32to travel longitudinally along the length of the strand30. The loop32defines an apex A which is preferably located about 0.35 mm or greater away from the crossbar24. The loop32also defines a cross-point CP where the ends of the strand30cross each other. The cross-point CP is preferably positioned radially outside the outer surface of the crossbar24including radially outside the side walls of the aperture38, but also preferably as close to the crossbar24as possible. The aperture38preferably extends a longitudinal distance in a range of about 0.4 mm to about 3.0 mm, while the crossbar24typically has a length in the range of about 3.0 mm to about 10.0 mm. The strand preferably has a diameter less than about 50% of a diameter of the crossbar24, and most preferably less than about 35%. The strand30preferably has a diameter in the range of about 0.20 mm to about 0.35 mm, and most preferably about 0.254 mm. The crossbar24preferably has a diameter in the range of about 0.5 mm to about 1.0 mm, and most preferably about 0.8 mm. The strand30may be coated with a low-friction material such as known plastic or hydrophilic coatings.

This construction of the tissue anchor24and its loop32allows the suture22to be tensioned and slid through the loop32relative to the crossbar24while preventing the suture22from engaging the crossbar24or the edges defined by the elongated aperture38. That is, no matter which direction the ends of the suture22are pulled or slid relative to the crossbar24, the wire30and its loop32will serve as a barrier between the suture22and the canula24to prevent any undesired abrasion therebetween. Generally, the strand30has a length and the location of the apex A of the loop32are such that the loop32is sized to project through the tissue in which it is embedded (e.g. it projects from the proximal side of the tissue), allowing reliable tensioning of the suture22and preventing abrasion of the tissue.

Turning now toFIG. 3, another embodiment of a tissue anchor120is depicted in accordance with the teachings of the present invention. As in the prior embodiment, the anchor120generally includes a crossbar124having opposing ends126and128. A strand130is connected to the crossbar124, and in this embodiment, the strand130is formed of a flexible suture. The crossbar24defines first and second apertures138,140which are longitudinally spaced apart. Moving from left to right inFIG. 3, the strand130is attached to the crossbar124and passes through the interior of the crossbar124and exits radially from the first aperture138, then extends along the outer periphery of the crossbar124, and passes back through the second aperture140into the interior of the crossbar124, where it is fixed to the second end128thereof. Accordingly, the flexible suture130and the crossbar124define a loop132therebetween which is sized to slidably receive the tying suture22. The suture130has a length, preferably about 10 mm to about 30 mm, such that the distance the suture130projects away from the crossbar124is variable. The suture130, when pulled taut, defines an apex that is positioned away from an outer surface of the crossbar about 5 mm. Preferably the suture130has a length 18 mm, whereas the crossbar124has a length of about 8 mm. The suture130may be of a single filament or multi-filament constructions. Through this construction of the suture130to form the loop132, while friction between the anchor120and the tying suture22is reduced. The loop132and with the extra length of the suture130, the crossbar124may be embedded deeper into the tissue.

Turning now toFIGS. 4 and 5, in yet another embodiment of a tissue anchor220has been depicted in accordance with the teachings of the present invention. As with the prior embodiments the anchor220generally includes a crossbar224having opposing ends226and228. In this embodiment the crossbar224is preferably formed of a solid cylinder, and may be a metal bar, plastic molded piece, or any stock materials. The tissue anchor220also includes a flange240connected to the crossbar224and projecting radially away therefrom. The flange240preferably has a thickness (best seen in the side view ofFIG. 5) that is less than 50% of the diameter of the crossbar224. The flange240defines a hole242sized to slidably receive the tying suture22therein. Preferably, the crossbar224and flange240are unitarily and integrally formed, such as in a plastic molding process. Accordingly, the entire tissue anchor220may be formed of a single plastic material, and most preferably a resorbable material. This construction of the tissue anchor220allows it to be placed in locations where, once the anchor was freed, it would likely not naturally pass through the body. Accordingly, no matter the location the tissue anchors220, they are still allowed to naturally exit the body.

As used herein, the term “resorbable” refers to the ability of a material to be absorbed into a tissue and/or body fluid upon contact with the tissue and/or body fluid. A number of resorbable materials are known in the art, and any suitable resorbable material can be used. Examples of suitable types of resorbable materials include resorbable homopolymers, copolymers, or blends of resorbable polymers. Specific examples of suitable resorbable materials include poly-alpha hydroxy acids such as polylactic acid, polylactide, polyglycolic acid (PGA), or polyglycolide; tri-methlyene carbonate; polycaprolactone; poly-beta hydroxy acids such as polyhydroxybutyrate or polyhydroxyvalerate; or other polymers such as polyphosphazines, polyorgano-phosphazines, polyanhydrides, polyesteramides, poly-orthoesters, polyethylene oxide, polyester-ethers (e.g., poly-dioxanone) or polyamino acids (e.g., poly-L-glutamic acid or poly-L-lysine). There are also a number of naturally derived resorbable polymers that may be suitable, including modified polysaccharides, such as cellulose, chitin, and dextran, and modified proteins, such as fibrin and casein.

Turning now toFIGS. 6-9, the tissue anchors20are preferably deployed as a set of anchors20a,20b,20c,20dlinked together by a single suture22, all of which collectively forms a medical device50for closing the perforation10in the bodily wall12. The suture22is slidably connected to each of the tissue anchors20a,20b,20c, and20d, leaving two free ends52,54of the suture22which may be independently tensioned to close the perforation10. As best seen inFIG. 7, the tissue anchors (20band20cdepicted) are positioned on a distal side of the bodily wall12, while the majority of suture22is positioned on a proximal side of the bodily wall12, including the suture ends52,54. Accordingly, it will be recognized that the medical device50operates in a purse-string fashion to close the perforation10in the bodily wall, as will be described in more detail below.

A method of closing the perforation10, in accordance with the teachings present invention, includes passing each tissue anchor20a,20b,20c, and20dthrough the bodily wall12adjacent the periphery of the perforation10, as shown inFIG. 6. Preferably, the anchors are sequentially positioned around the perforation10in a semi-annular or annular shape as shown. The ends52,54of the suture are then tensioned to reduce the distance between the tissue anchors20a,20b,20c,20dand compress the bodily wall12around the perforation10, as depicted inFIGS. 8 and 9. As best seen inFIG. 9, the ends52,54of the suture22are secured to maintain the compression of the bodily wall10, such as through the use of a suture lock56. Exemplary suture locks are disclosed in copending U.S. patent application Ser. Nos. 12/125,525 and 12/191,001, the disclosures of which are incorporated herein by reference in their entirety. It will be recognized that any now known or future developed method for securing the ends52,54of the suture22may be employed, such as knotting, tying, clamps, rivets and the like.