Surgical fastener

Various embodiments of a non-deforming surgical fastener are discussed. In one embodiment, the fastener includes two legs and a backspan extending between the two legs. The fastener also includes a backspan thickness that is adapted to reduce the pressure and/or increase the holding strength applied to underlying materials. The non-deforming fastener is constructed and arranged to retain substantially the same shape before, during and after deployment into the target implantation site.

FIELD

Aspects relate to a surgical fastener.

BACKGROUND

Surgical fasteners are widely used in many different medical procedures. For example, staples, sutures, clips and other fasteners are commonly used in laparoscopic and open surgical procedures.

SUMMARY

According to one embodiment a surgical fastener includes a first leg, a second leg, and a backspan extending from the first leg to the second leg. The backspan includes a central pad with a thickness greater than a thickness of the backspan extending between the central pad and either the first leg or second leg. The surgical fastener is a non-deforming fastener such that the first and second legs are constructed to remain in an open position after deployment of the fastener.

According to another embodiment, a method includes: deploying a non-deforming fastener into tissue, wherein a pressure applied to the underlying tissue by the fastener is greater than or equal to 27.5 kPa and less than or equal to 275 kPa.

According to yet another embodiment, a surgical fastener includes a first leg, a second leg, and a backspan extending from the first leg to the second leg. The backspan has an area less than or equal to 10 mm2and greater than or equal to 0.25 mm2. The surgical fastener is a non-deforming fastener such that the first and second legs are constructed to remain in an open position after deployment of the fastener.

DETAILED DESCRIPTION

The inventors have appreciated the benefits associated with a surgical fastener capable of applying reduced pressures over larger areas to an underlying prosthetic and/or tissue. For example, a surgical fastener might apply a larger total holding strength over a greater area, while subjecting an underlying prosthetic and/or tissue to a relatively low pressure during insertion. Alternatively, a surgical fastener might distribute a desired holding force across a larger area to avoid applying excessive pressure to an underlying prosthetic and/or tissue. In view of the above, the inventors have recognized that a surgical fastener including a backspan with an increased surface area may be used to provide reduced pressures and/or increased retention forces as compared to typical surgical fasteners.

Depending on the particular application, some types of surgical fasteners are designed to deform during deployment. For example, some surgical staples have legs that curl inward into a closed position as the staple is deployed into a tissue and/or prosthetic in order to secure the staple at the desired implantation site. Therefore, as used herein, a “deforming” fastener is one that is constructed and arranged to change shape as it is deployed into the target implantation site.

In contrast to the above, as used herein, a “non-deforming” fastener is one that is constructed and arranged to retain substantially the same shape before and after deployment into a target implantation site. While non-deforming fasteners may undergo some permanent deformation such as dents or shape alterations due to contact with hard materials or due to some amount of elastic deformation, the legs of such non-deforming fasteners are not designed or intended to bend or deform during normal use. Instead, the legs of the surgical fasteners are deployed in an open position and remain in the open position after deployment as well.

The surgical fasteners disclosed herein may be made from any appropriate material including various appropriate metals and polymers. Additionally, the material may be selected such that the surgical fastener is non-absorbable or bioabsorable as the current disclosure is not so limited. For example, a non-absorbable surgical fastener may be made from: a stainless steel, such as 316L stainless steel, titanium, a nickel titanium based alloy such as nitinol, polypropylene, a high density polyurethane, ultra high molecular weight polyethylene (UHMWPE), nylon, polyester or any other appropriate material. Appropriate bioabsorbable materials include, but are not limited to magnesium, zinc, manganese and iron, or their combination alloy, polylactic acid, polyglycolic acid, copolymers thereof, and the like.

The disclosed surgical fastener may also be manufactured in any appropriate fashion. For example, the surgical fastener may be integrally formed such that the fastener comprises a single monolithic component. In other embodiments, the fastener may be assembled by forming separate portions of the fastener and attaching them together using an adhesive, a welding process, or any suitable method or substance, as this aspect is not so limited.

For the sake of clarity, the embodiments depicted in the figures are directed to a laparoscopic device. However, the current disclosure is not limited to laparoscopic devices. Instead, the currently disclosed surgical fasteners could be used in any appropriate device for the deployment of a surgical fastener into tissue. For example, the surgical fasteners could be used in an endoscopic device, a borescopic device, a catheter, a deployment device for use in “open” procedures, or any other appropriate deployment device. Additionally, a device might use any number of surgical fasteners.

For the purposes of this application, a barb associated with the surgical fastener is not considered to be part of a leg that it extends from.

Turning now to the figures, embodiments related to a non-deforming surgical fastener with a widened backspan capable of applying reduced pressures and/or increased holding strength to underlying materials is described.

FIG. 1depicts an exemplary fastener deployment device1for deploying one or more surgical fasteners into a prosthetic and/or tissue. The deployment device includes a handle4at a proximal end of the device and an actuation button such as a trigger2on the handle. The deployment device also includes a shaft5extending in a distal direction from the handle4. Actuating the trigger2moves fasteners inside shaft5in a direction from the proximal end6of the shaft to the distal end8, and deploys a distal-most surgical fastener from the distal end8of the shaft5. It should be understood that the deployed surgical fastener may be deployed into any appropriate prosthetic which may be embodied by any number of different components or materials. For example, in one embodiment, the prosthetic may be a soft tissue repair fabric, such as a surgical mesh, used for repairing a hernia.

FIGS. 2-4depict one embodiment of a non-deforming surgical fastener10. In the depicted embodiment, the fastener10has two legs20extending in a distal direction. While two legs are depicted, it should be understood that any number of legs might be used. Each leg20includes a distal tip that is adapted to be inserted into a prosthetic and/or tissue. In some embodiments, and as illustrated in the figures, the distal tips of the legs20include sharpened points52though non-sharpened points are also possible. The legs20are connected to opposing ends of a backspan36to form a surgical fastener with a somewhat U-shaped profile. Other profile shapes are also possible. For example, the surgical fastener10may have a C-shaped profile or any other desirable profile as the current disclosure is not limited in this fashion. As shown inFIG. 2, the legs20are in an open position. The legs20remain in the open position after deployment as well.

As seen inFIG. 2, the fastener may include outer corners35where the leg20and the backspan36meet. In the embodiment shown inFIG. 2, the outer corners35are rounded. However, in other embodiments, the outer corners35may be chamfered, angled or have any other suitable shape. As seen inFIG. 3, the fastener also includes inner corners33where the legs20and the backspan36meet. In the embodiment shown inFIG. 3, the inner corners33are rounded. However, similar to the above, in other embodiments, the inner corners33may also be chamfered, angled or have any other suitable shape.

In some embodiments, the surgical fastener includes an anchoring feature such as one or more barbs to keep the fastener anchored to the underlying prosthetic and/or tissue once it has been deployed. For example, as shown inFIG. 2, barbs54may be located on the distal ends of legs20of the fastener. In the depicted embodiment, the barbs54point away from the distal tips52of the legs toward the proximal direction (away from the direction of deployment). Without wishing to be bound by theory, such barbs will increase the pull out force required to remove the fastener from the target implantation site. While the embodiment shown inFIG. 2includes two barbs per leg, any number of barbs may be used, as this aspect is not so limited. For example, in the embodiment shown inFIG. 5, the legs have a third barb55. In addition, barbs may be located on the legs, the backspan or on any other suitable portion of the fastener. It should also be understood that while barbs have been described above, any appropriate anchoring feature might be used including, but not limited to, surface roughness or other suitable treatment to increase the pull out force of the surgical fastener.

In some embodiments, the anchoring feature may be provided at different heights along the fastener leg. In the embodiment shown inFIG. 2, the barbs54are arranged at the same height along leg20. In other embodiments, however, barbs may be arranged at different heights along the fastener legs. For example, in the embodiment shown inFIGS. 6A-6B, barbs71and73are positioned at different heights along leg21. Without wishing to be bound by theory, barbs or other anchoring features at different heights along the fastener leg will engage with tissue and/or a prosthetic at multiple depths and may result in increased pull out resistance.

It should be appreciated that the barbs shown in the figures are illustrative examples and may be varied. For example, the barbs may have longer lengths and may have any suitable angle and shape to provide pull out resistance. In addition, whileFIG. 2depicts the distal tip52of leg20as being symmetrical, the distal tip of the fastener tip may be asymmetrical. For example, as shown inFIGS. 6A-6B, the distal tip53of leg21is asymmetrical, where the left side of the tip is slanted and the right side of the tip is vertical.

The inventors have also appreciated that certain barb orientations may allow an increased width of the fastener backspan while satisfying the constraints that arise with use of the fastener within the confined space of a shaft. As shown inFIG. 3, the fastener may have a width W1corresponding to the length between the two exterior sides of the legs20that is sized to be delivered through an outlet of the delivery shaft. In some cases, the barbs may be oriented to permit as wide a backspan width W1as possible that still permits the fastener to be delivered through the outlet of the delivery shaft. As shown inFIGS. 2-3, in some embodiments, the barbs54may extend in a direction that is perpendicular to the width W1(the barbs54extend in and out of the page inFIG. 3along the z-axis). Having the barbs oriented in this way may permit the legs20to be spaced as far apart as possible within the constraints of delivery through a surgical port, thereby increasing the backspan width W1. However, other barb orientations are also possible. For example, in the embodiment shown inFIG. 5, the fastener has a third barb55pointed in a direction that is perpendicular to barb54. In some embodiments, the third barb55points inwards towards a central axis of the fastener and thus does not increase the overall width of the fastener profile.

Depending on the embodiment, the fastener10may have a width W1extending between the exterior sides of the two legs of about 4 mm to 4.9 mm, 4.1 mm to 4.8 mm, 4.2 mm to 4.7 mm, 4.3 mm to 4.6 mm, or 4.4 mm to 4.5 mm inclusive. However, it should be understood that other suitable widths are possible, as this aspect is not so limited.

As also shown inFIG. 3, the fastener may have a height H1from a top surface of the fastener to the distal pointed tips of the legs of about 3 mm to 6.5 mm, 3.5 mm to 5 mm, or 4 mm to 4.5 mm, inclusive. However, it should be understood that other suitable heights are possible, as this aspect is not so limited.

In addition to the general structure described above, the backspan36can include a central pad30. As best seen inFIG. 3, the central pad30may protrude downward slightly from the bottom surface25of the backspan. Without wishing to be bound by theory, such a protrusion31may help the fastener to maintain flush contact with an underlying prosthesis and/or tissue once it has been deployed. The central pad30may have a height H2of about 0.25 mm to 1 mm, 0.35 mm to 0.9 mm, 0.45 mm to 0.8 mm, or 0.55 mm to 0.7 mm, inclusively. The central pad30may also extend between about 0 mm to 0.65 mm inclusively below the bottom surface25of the backspan. In other embodiments, the central pad30may extend inclusively between about 0.1 mm to 0.65 mm, 0.2 mm to 0.65 mm, 0.3 mm to 0.65 mm, 0.4 mm to 0.65 mm, 0.5 mm to 0.65 mm, or any other appropriate distance below the bottom surface25. Additionally, the surgical fastener may include a transition27from the bottom surface25of the backspan to the bottom of the central pad30that may be curved in a concave downwards shape as depicted in the figure. However, in other embodiments, the transition27may be concave upwards, a flat slant, rounded, chamfered, or any other suitable shape. While the central pad30has been depicted as protruding below the bottom surface25of the backspan, it should be appreciated that in some embodiments, the bottom of the central pad may be flush with the bottom surface25of the backspan such that no transition between the two exists.

In some embodiments, the transition29from the top surface26of the backspan36to the top surface of the central pad30is curved. As shown inFIG. 3, in some embodiments, the transition29is concave downwards. In other embodiments, the transition may be concave upwards, a flat slant, rounded, chamfered, or any other suitable shape. However, it should be appreciated that in some embodiments, the top surface26is coplanar with the top of the central pad30such that no transition between the two exists.

In some embodiments, the central pad of the backspan may be thicker than each of the legs and/or a portion of the backspan attached to the central pad. For example, as shown inFIG. 2, the thickness T2of central pad30may be greater than the thickness T1of leg20which is also the thickness of the backspan portions attached to the central pad. In some cases, having a central pad30with an increased thickness T2may increase the surface area of the fastener backspan36, which may further reduce the pressure applied to underlying material when the fastener is deployed. In one embodiment, the legs20may have a thickness T1of about 0.25 mm to 3.5 mm, 0.75 mm to 3.0 mm, 1.25 mm to 2.5 mm, or 1.75 mm to 2 mm, inclusive. The central pad30of the fastener may have a thickness T2of about 0.25 mm to 3.5 mm, 0.75 mm to 3.0 mm, 1.25 mm to 2.5 mm, or 1.75 mm to 2 mm, inclusive. In some embodiments, the width W2 of the central pad is less than the width W1of the backspan. In other embodiments, however, the width of the central pad is equal to the width of the backspan. While any appropriate width might be used, in one embodiment, the central pad may have a width W2 of about 0.25 mm to 3.5 mm, 0.75 mm to 3.0 mm, 1.25 mm to 2.5 mm, or 1.75 mm to 2 mm, inclusive.

In view of the above, the central pad may have an area between about 0.1 mm2to 10 mm2, 1 mm2to 10 mm2, 2 mm2to 10 mm2, 5 mm2to 10 mm2, or any other appropriate area. Additionally, the backspan, which includes the central pad, may have an area between about 0.25 mm2to 10 mm2, 1 mm2to 10 mm2, 2 mm2to 10 mm2, 5 mm2to 10 mm2, or any other appropriate area. Without wishing to be bound by theory, a surgical fastener including a backspan with dimensions as noted above, or other appropriate dimension, may be designed to provide a pressure that is greater than or equal to 27.5 kPa (4 psi) and less than or equal to 275 kPa (40 psi) for a particular deployment force. In other embodiments, the pressure may be between about 27.5 kPa (4 psi) to 200 kPa (29 psi), 27.5 kPa (4 psi) to 150 kPa (21.8 psi), 27.5 kPa (4 psi) to 100 kPa (14.5 psi), 27.5 kPa (4 psi) to 50 kPa (7.3 psi), or any other appropriate pressure. Typical deployment forces can be greater than or equal to about 4.4 N (1 lbf) and less than or equal to about 44 N (10 lbf). In other embodiments the deployment force may be inclusively between about 4.4 N (1 lbf) to 30 N (6.8 lbf), 4.4 N (1 lbf) to 20 N (4.5 lbf), 4.4 N (1 lbf) to 10 N (2.3 lbf), or any other appropriate deployment force.

As depicted inFIG. 4, the central pad30can include rounded corners37connecting the central pad connects to the rest of the backspan. However, the corners37may be any other suitable shape including chamfered, angled, or right angles as the current disclosure is not so limited.

According to one aspect, the fastener backspan width and thickness are selected to fit within a certain surgical port size while being both wide and thick enough (width being in the X-direction and thickness being in the Z direction, seeFIG. 2) to reduce the pressure and/or increase the holding strength applied to underlying materials to desired thresholds. As an example, a common port size used in laparoscopic surgeries is a 5 mm port. Therefore, in some embodiments, the fastener dimensions are selected to be used with such a port.

As seen inFIGS. 2 and 4, in some embodiments, the central pad30of the fastener can include a through-hole40. In such an embodiment, a mandrel or guide rod of the fastener deployment device1passes through the through-hole40of each fastener to guide and stabilize the fasteners as they are moved distally through the fastener deployment device and subsequently deployed. Alternatively or in addition to the above, the through-hole40may allow tissue ingrowth, which may help to stabilize the fastener at the target implantation site.

According to one aspect, the fasteners may be shaped to be stackable inside a fastener deployment device. Therefore, in some embodiments, a fastener deployment device includes a plurality of surgical fasteners that are arranged in any appropriate fashion within the shaft. When the distal-most fastener is deployed, the rest of the fasteners are sequentially advanced in a deployment direction. In some embodiments, the top surface24of the backspan of a fastener includes recesses (not depicted) that are shaped and arranged to receive the distal ends of the legs of a proximally located adjacent fastener (not depicted). Receiving and retaining the legs of one fastener within the recesses of an adjacent fastener may help to decease lateral slippage between adjacent fasteners as they are advanced distally through the fastener deployment device. As a result, such a stacking feature may help fasteners to remain aligned within a fastener deployment device as the fasteners are advanced. While a particular arrangement is described above, any suitable stacking feature may be used, as this aspect is not so limited.

It should be appreciated that the fasteners shown inFIGS. 2-4are illustrative embodiments, and that other arrangements are possible. Specifically, the fastener may have more than two legs. In such an embodiment, the fastener may have three or more legs, or any other number of legs, that are evenly spaced from one another. For instance, if the fastener has three legs, the legs could be spaced 120° apart from one another. Similarly, if the fastener has four legs, the legs could be spaced 90° apart from one another. Alternatively, the legs might be spaced at regular intervals according to length. However, in other embodiments, the legs may be spaced at irregular intervals.

The above aspects and embodiments may be employed in any suitable combination, as the present invention is not limited in this respect.