Surgical fastener

An improved surgical fastener of the type used in a surgical applicator which has been modified to enhance the gripping capability of the fastener once secured. The fastener can have apertures therethrough or the surface can be knurled, crimped, etched with a laser, layered with an abrasive coating, sand blasted, punched, notched, or modified in any other manner which enhances the grip of the fastener when secured. Additionally, the fastener can be formed from or coated with a magnetic material, which provides additional holding power to maintain the clip closed after it has been secured into the tissue. An alternate embodiment includes a double wall to reinforce the fastener when secured.

FIELD OF THE INVENTION 
The present invention relates to surgical fasteners. More particularly, the 
present invention relates to improved surgical fasteners of the type which 
are secured by surgical applicators. In even greater particularity, the 
present invention relates to improvements in surgical staples and clips. 
BACKGROUND OF THE INVENTION 
Surgical fasteners, including clips and staples, and methods of applying 
these fasteners are well known in the art. Surgical fasteners can be used 
to close incisions or wounds, or to clamp vessels or ducts to prevent 
fluid flow. Surgical applicators used to apply these fasteners comprise 
various designs depending on the use to which the fasteners are employed. 
For example, a clip applicator is typically a pistol-shaped vise used 
where a vessel or duct must be sealed. The clip is directed to the 
location of application and then the vise secures the clip, collapsing and 
sealing the vessel. A surgical stapler is typically used where an incision 
or wound must be closed. A surgical stapler typically employs an anvil to 
form the fastener during application. With increasing use and improvement 
of various surgical applicators, fasteners have also improved. Some 
examples of surgical fasteners are found in U.S. Pat. Nos. 4,407,286; 
4,489,875; and 4,932,960. 
In the '286 patent, Noiles et al. disclose a surgical staple which is 
designed to reduce the tendency of the staple to slip off the anvil during 
application or to adhere to the anvil after application. In the '875 
patent, Crawford et al. disclose a self-centering staple to remedy the 
problem of misalignment of the staple during application. In the '960 
patent, Green et al. disclose a bioabsorbable fastener designed for 
elastic expansion to prevent breakage. Although the foregoing surgical 
fasteners, as well as others known in the art, have addressed and remedied 
many problems encountered with the use of these fasteners, there still 
exist problems accompanying their use. 
One such problem is the slippage of fasteners at the point of their 
application in the tissue. During surgery it is frequently required to 
shut off fluid transfer to areas, thus fasteners are often placed around 
blood vessels or other structures to achieve this. For example, in cases 
where polyps are to be removed, fasteners are typically applied to the 
base of the structure to shut off fluid transfer and the polyp is removed. 
The fastener is left in place during the healing process to prevent fluid 
loss. As hydrostatic pressure increases due to the blockage, fasteners 
tend to slip away from the pressurized area which can result in fastener 
displacement and fluid loss or hemorrhage. Another problem seen with 
currently used fasteners concerns the closure of the fastener itself. 
During application of the fastener, the typical U or V-shaped designs 
often result in non-uniform closure of the fastener over the vessel, which 
again can lead to fastener displacement as well as fluid loss or 
hemorrhage. To avoid these problems, the fastener is tightly fastened into 
the tissue encompassed by the fastener, which still does not guarantee 
against slippage. In addition, in surgeries where fasteners are employed 
to temporarily shut off blood flow through a vessel, this form of 
application can cause irreparable injury to the vessel. 
From the foregoing it may be seen that a need exists for an improved 
surgical fastener which is designed to resist displacement once secured to 
the tissue. 
SUMMARY OF THE PRESENT INVENTION 
It is the object of the present invention to provide an improved surgical 
fastener of the type used in surgical applicators which resists 
displacement once secured to the tissue. 
It is another object of the present invention to provide a fastener which 
can be used in surgical applicators presently available. 
These and other objects of the present invention are accomplished through 
the use of a surgical fastener which has been modified to enhance the 
gripping capability of the fastener once secured. The fastener can have 
apertures therethrough or the surface can be knurled, crimped, etched with 
a laser, layered with an abrasive coating, sand blasted, punched, notched, 
or modified in any other manner which enhances the grip of the fastener 
when secured. Additionally, the fastener can be formed from or coated with 
a magnetic material, which provides additional holding power to maintain 
the clip closed after it has been secured into the tissue. For purposes of 
this disclosure, a knurled surface refers to a surface which has been 
roughened to provide an enhanced grip. Examples of knurling include 
serrations, dimples, protrusions, cross-hatches, grooves, and flutes 
pressed into a surface. The abrasive coating is a material such as 
non-toxic paint containing a plurality of solid particles wherein these 
particles form protrusions in the coating once applied to the fastener. 
The modification can be continuous over the entire surface of the fastener 
or it can be only on the tissue contacting surface, and can additionally 
have modified regions intermixed with unmodified regions. During the 
application of the fastener to the target tissue, the tissue conforms to 
the modified surface of the fastener. This results in resistance to 
slippage because the fastener surface presses into the tissue causing 
depressions in the tissue. Subsequently, tissue edema and growth 
encapsulates and integrates into deformities in the fastener. An alternate 
embodiment includes a double wall to reinforce the fastener when secured. 
These and other objects and advantages of the invention will become 
apparent from the following detailed description of the preferred 
embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A more complete understanding of the invention may be obtained by reference 
to the accompanying drawings wherein the fastener, according to the 
embodiment illustrated in FIG. 1, is a square-cornered U-shaped member 10 
having a base 11 and at least two parallel legs 12. The preferred 
embodiment is composed of titanium or stainless steel, although other 
metals, plastics, or ceramics can be used, as well as malleable wire. The 
preferred embodiment has a square cross-section, although the 
cross-section can be round or have any polygonal shape. Other embodiments 
of the present invention include a linear shaped member shown in FIG. 14, 
a V-shaped member shown in FIG. 15, other U-shaped members shown in FIG. 
16 and FIG. 17, or a C-shaped member shown in FIG. 18. Another beneficial 
feature is a novel double wall, which acts to reinforce the fastener when 
secured. Embodiments of the present invention illustrating the double wall 
feature are shown in FIGS. 19-22, discussed in further detail hereinbelow. 
The embodiment of choice can depend on the personal preference of the user 
as well as the procedures for which the fasteners are to be used. 
Typically, fasteners embodying features of my invention are formed from a 
sheet, or wire, of titanium or stainless steel which has been modified 
with a texturizing feature. Moreover, the fasteners can be formed from or 
coated with a magnetic material, which provides additional holding power 
to maintain the clip closed after it has been secured into the tissue. The 
sheets or wires are pulled from preformed rolls having a thickness usually 
between 0.015 to 0.025 inches. As the sheet or wire is pulled from the 
roll, it is pulled though a device for texturizing the sheet or wire. This 
texturizing device can be a crimping mechanism for crimping the sheet or 
wire; a knurling mechanism for pressing serrations, dimples, protrusions, 
cross-hatches, grooves, or flutes into the surface of the sheet or wire; 
an applicator for applying a non-toxic abrasive coating containing a 
plurality of solid particles to the surface of the sheet or wire; a series 
of lasers for etching into, or forming apertures through, the sheet or 
wire; a sand blasting chamber for pitting the surface of the sheet or 
wire; or a mechanical punch for punching dimples into, or apertures 
through, the sheet or wire. All the foregoing texturizing devices are well 
known in the various arts of manufacturing and are not shown. The sheet or 
wire can have the texturizing feature placed on only one side or on both 
sides. In addition, the texturizing feature can be continuous or it may be 
intermixed with unmodified regions. 
Some illustrations of the texturizing features include a cross-hatch design 
as illustrated in FIG. 2, dimples as illustrated in FIG. 3, protrusions as 
illustrated in FIG. 4, linear grooves as illustrated in FIG. 5, 
curvilinear grooves as illustrated in FIG. 6, etchings from a laser as 
illustrated in FIG. 7, a layer of an abrasive coating as illustrated in 
FIG. 8, apertures from a mechanical punch or laser as illustrated in FIG. 
9, crimping as illustrated in FIG. 10, or pitting from sand blasting as 
illustrated in FIGS. 19-22. In addition, the edges of the fasteners can 
have notches as illustrated in FIG. 11, which result from forming the 
dimples or apertures along a line where the individual fasteners will 
subsequently be separated. Some of the modifications are only effective to 
prevent slippage in one direction, such as the linear grooved surface of 
FIG. 5. The grooves of FIG. 5 are shown longitudinal along the fastener in 
order to prevent slippage of the fastener along the longitudinal of a 
blood vessel or the like, but could as easily be transverse along the 
fastener if another result was desired. 
After the texturizing feature has been added, the sheet or wire is pulled 
into a cutting device, typically comprising a die having a plurality of 
longitudinal and transverse knives if sheets are used. As the die is 
actuated into contact with the sheet, the longitudinal knives cut the 
sheet into a plurality of bands, usually between 0.20 to 0.35 inches, 
which is to become the length of the fasteners. Simultaneously, the 
transverse knives cut into, but not quite through, the sheet to form a 
plurality of fasteners, each fastener having a width usually between 0.015 
to 0.030 inches. The individual fasteners are not separated from the band 
at this point but are not securely attached to each other and could be 
easily separated by hand. In the case of wire, the wire is cut into a 
plurality of members having a length usually between 0.20 to 0.35 inches, 
which is to become the length of the fasteners. The wire members are 
subsequently juxtaposed to form bands for further processing. If the 
embodiment of the fasteners is linear shaped as shown in FIG. 14, then the 
fasteners are packaged with a predetermined number of fasteners per 
package and distributed. However, if the fasteners are to be formed into 
the other embodiments shown in FIGS. 1, and 15-22, then the bands of 
fasteners are processed further. 
After leaving the cutting device, the bands of fasteners are pulled into a 
press where an upper plate having a plurality of linear ridges presses the 
bands into a reciprocal lower plate having a plurality of linear grooves 
corresponding to the ridges in the upper plate. The number of ridges or 
grooves equals the number of bands so that each band is pressed into only 
one groove. The shape of the groove complements the shape of the ridge so 
that when a band of fasteners is pressed between the ridge and groove, the 
band of fasteners will take on the form of the ridge or groove, which 
corresponds to the embodiments shown in FIGS. 1, and 15-18. The fasteners 
are then packaged with a predetermined number of fasteners per package and 
distributed. 
To make the embodiments illustrated in FIGS. 19-22, the fasteners are 
formed such that the bands are substantially wider (i.e., the length of 
the fastener) than the fasteners described hereinabove. After formation as 
described above, the distal ends of the elongated arms are folded back to 
form the inner wall 11 of the fastener. The distal ends are preferably 
folded in such a manner that the fastener ends 12 are in contact with each 
other. The outer wall 13 is preferably U-shaped, such that the outer 
portions 14 of the arms are parallel to each other, although this is not 
critical. The inner wall 11 of this embodiment can have various shapes, 
depending on the personal preference of the user as well as the procedures 
for which the fasteners are to be used. A fastener having an inner 
V-shaped wall is shown in FIG. 19; a fastener having an inner U-shaped 
wall is shown in FIG. 20; a fastener having an inner oval-shaped, or 
modified C-shaped, wall is shown in FIG. 21; and a fastener having an 
alternate inner V-shaped wall is shown in FIG. 22. It is to be understood 
that the fasteners of this embodiment are to be used in the surgical 
devices already existing. Accordingly, it may be seen that the addition of 
a secondary wall will diminish the space within the crimping or clamping 
device such that an additional mass of metal is compressed. By compressing 
the greater mass within the same volume a more certain seal is achieved. 
Note that the fastener walls are not merely thickened but formed in 
discrete segments to enhance the engagement about the vessel by selection 
of the particular inner configuration as shown. 
The fasteners of the present invention can be used in surgical staplers 
utilizing anvils or in surgical applicators utilizing a vise. Application 
of surgical fasteners has been well documented in the prior art and will 
not be repeated here. A good example of the application of fasteners with 
an anvil type surgical stapler was discussed by Noiles et al. in U.S. Pat. 
No. 4,407,286. The present discussion will focus on the fastener during 
and after application into the tissue. As the fastener is secured to close 
incisions or wounds, or to clamp vessels or ducts to prevent fluid flow, 
the novel features of the present invention become apparent. As the 
fastener closes around tissue, the tissue forms about the texturizing 
features. Since the interface between the fastener and the tissue is not 
smooth, but rather rough and abrasive, the fastener will resist 
displacement arising from hydrostatic pressure, movement of adjacent 
tissues, or other occurrences which would tend to displace the fastener. A 
fastener embodying features of my invention is shown secured to a blood 
vessel in FIG. 12 and maintaining closure of an incision in FIG. 13. 
Furthermore, the embodiment comprising the double wall feature illustrated 
in FIGS. 19-22 has the added benefit of an outer wall 13 to promote 
uniform compression of the inner wall 11 during application of the 
fastener. During application of presently used fasteners, the resistance 
from tissue can deform the fasteners, such that there is not uniform 
closure. This can subsequently lead to displacement of the fastener and 
fluid loss or hemorrhage. The outer wall 13 of the present invention acts 
to bolster the inner wall 11 during application of the fastener so that 
the inner wall will compress properly over the tissue, and subsequently 
adds fortification to the inner wall to prevent deformation from 
increasing hydrostatic pressure in the tissue. 
It is to be understood that the form of the invention shown is a preferred 
embodiment thereof and that various changes and modifications may be made 
therein without departing from the spirit of the invention or scope as 
defined in the following claims.