Surgical needle abstract
A barbed suture for connecting tissue, and a combination surgical
needle with a barbed suture. The suture includes an elongated body
and a plurality of barbs projecting from the body. Each barb causes
the suture to resist movement in an opposite direction from which
the barb faces. The disposition of the barbs on the body may be
staggered, twist cut multiple spiral, overlapping, or random. Also,
the configuration of the barbs may be a certain spirality angle
.alpha., barb cut angle .theta., barb cut depth, barb cut length,
barb cut distance, corrugated barb underside, arcuate barb base,
or varying barb size.
Surgical needle claims
1. A barbed suture for connecting human or animal tissue in combination
with a surgical needle, said combination comprising a barbed suture
attached to a surgical needle, wherein the suture comprises a plurality
of barbs projecting from an elongated body having a first end and
a second end and a diameter, each barb facing in a direction and
being adapted for resisting movement of the suture, when in tissue,
in an opposite direction from the direction in which the barb faces,
and wherein the surgical needle has a diameter at the needle's thickest
part with a ratio of the surgical needle diameter to the barbed
suture diameter of from about 3:1 to about 1.1:1.
2. The barbed suture and surgical needle combination according
to claim 1 wherein the barbed suture and the surgical needle have
an attachment selected from the group consisting of swaging, channel
wrapping, heat shrinking, and eyelet threading.
3. The barbed suture and surgical needle combination according
to claim 1 wherein the surgical needle has a polymeric coating.
4. The barbed suture and surgical needle combination according
to claim 3 wherein the polymeric coating comprises a silicone material.
5. The barbed suture and surgical needle combination according
to claim 1 wherein the ratio of the surgical needle diameter to
the barbed suture diameter is from about 2:1 to about 1.1:1.
6. The barbed suture and surgical needle combination according
to claim 5 wherein the ratio of the surgical needle diameter to
the barbed suture diameter is about 1.1:1.
7. The barbed suture and surgical needle combination according
to claim 1 wherein the suture is made from a material selected
from the group consisting of a bio-absorbable material, a non-absorbable
material, and combinations thereof.
8. The barbed suture and surgical needle combination according
to claim 7 wherein the bio-absorbable material is selected from
the group consisting of polydioxanone, polylactide, polyglycolide,
polycaprolactone, and combinations thereof.
9. The barbed suture and surgical needle combination according
to claim 7 wherein the non-absorbable material is selected from
the group consisting of a polymer, a metal, a metal alloy, a natural
fiber, and combinations thereof.
10. The barbed suture and surgical needle combination according
to claim 9 wherein the polymer is selected from the group consisting
of polyamide, polyester, polypropylene, polyurethane, polytetrafluoroethylene,
polyether-ester, and combinations thereof.
11. The barbed suture and surgical needle combination according
to claim 1 wherein the barbs have a disposition on the body selected
from the group consisting of a staggered disposition, a twist cut
multiple spiral disposition, an overlapping disposition, a random
disposition, and combinations thereof.
12. The barbed suture and surgical needle combination according
to claim 11 wherein the barbs are in a staggered disposition, a
twist cut multiple spiral disposition, an overlapping disposition,
or a combination thereof, and the barbs are all facing in a direction
toward only one of the first end and the second end.
13. The barbed suture and surgical needle combination according
to claim 11 wherein the barbs are in a staggered disposition, a
twist cut multiple spiral disposition, an overlapping disposition,
or a combination thereof, and the barbed suture has at least a first
barbed portion and a second barbed portion, wherein the barbs of
the first portion are facing in a direction toward only the first
end and the barbs of the second portion are facing in a direction
toward only the second end.
14. The barbed suture and surgical needle combination according
to claim 11 wherein the staggered disposition includes a first
set of the barbs being radially spaced about 180 degrees from a
second set of the barbs.
15. The barbed suture and surgical needle combination according
to claim 11 wherein the staggered disposition includes a first
set of the barbs being radially spaced about 120 degrees from a
second set of the barbs and the second set of the barbs being radially
spaced about 120 degrees from a third set of the barbs.
16. A barbed suture for connecting human or animal tissue in combination
with a surgical needle, said combination comprising a barbed suture
attached to a surgical needle, wherein the suture comprises a plurality
of barbs projecting from an elongated body having a first end, a
second end, and a diameter, each barb facing in a direction and
being adapted for resisting movement of the suture, when in tissue,
in an opposite direction from the direction in which the barb faces,
wherein the barbed suture and the surgical needle have an attachment
selected from the group consisting of swaging, channel wrapping,
heat shrinking, and eyelet threading, and wherein the surgical needle
has a diameter at the needle's thickest part with a ratio of the
surgical needle diameter to the barbed suture diameter of from about
2:1 to about 1.1:1.
17. A barbed suture for connecting human or animal tissue in combination
with a surgical needle, said combination comprising a barbed suture
attached to a surgical needle, wherein the suture comprises a plurality
of barbs projecting from an elongated body having a first end, a
second end, and a diameter, each barb facing in a direction and
being adapted for resisting movement of the suture, when in tissue,
in an opposite direction from the direction in which the barb faces,
wherein the barbs are in a staggered disposition, and wherein the
surgical needle has a diameter at the needle's thickest part with
a ratio of the surgical needle diameter to the barbed suture diameter
of from about 3:1 to about 1.1:1.
18. A barbed suture for connecting human or animal tissue in combination
with a surgical needle, said combination comprising a barbed suture
attached to a surgical needle, wherein the suture comprises a plurality
of barbs projecting from an elongated body having a first end, a
second end, and a diameter, each barb facing a direction and being
adapted for resisting movement of the suture, when in tissue, in
an opposite direction from the directing in which the barb faces,
wherein the barbs are in a staggered disposition, and wherein the
surgical needle has a diameter with a ratio of the surgical needle
diameter to the barbed suture diameter of about 3:1 to about 1.1:1.
19. A barbed suture for connecting human or animal tissue in combination
with a surgical needle, said combination comprising a barbed suture
attached to a surgical needle, wherein the suture comprises a plurality
of barbs projecting from an elongated body having a first end, a
second end, and a diameter, each barb facing in a direction and
being adapted for resisting movement of the suture, when in tissue,
in an opposite direction from the direction in which the barb faces,
wherein the barbs are in a random disposition, and wherein the surgical
needle has a diameter at the needle's thickest part with a ratio
of the surgical needle diameter to the barbed suture diameter of
about 3:1 to about 1.1:1.
Surgical needle description
CROSS-REFERENCES
[0001] This application is a continuation application of U.S. patent
application Ser. No. 10/065278 filed Sep. 30 2002 the entire
contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] This invention relates, in general, to a barbed suture useful
for connecting bodily tissue in various surgical contexts, and more
particularly, to the optimization of the disposition and/or configuration
of the barbs on such barbed sutures.
BACKGROUND OF THE INVENTION
[0003] Various surgical methods employing sutures have been used
in the past for closing or binding together wounds in human or animal
tissue, such as skin, muscles, tendons, internal organs, nerves,
blood vessels, and the like. More specifically, the surgeon may
use a surgical needle with an attached conventional suture (which
can be a smooth monofilament or can be a multi-filament) to pierce
the tissue alternately on opposing faces of the wound and thus sew
the wound closed. Whether the wound is accidental or surgical, loop
stitching is the method often used, especially for surface wounds.
The surgical needle is then removed and the ends of the suture are
tied, typically with at least three overhand throws to form a knot.
[0004] As is well known, conventional sutures can be of non-absorbable
material such as silk, nylon, polyester, polypropylene, or cotton,
or can be of bio-absorbable material such as glycolic acid polymers
and copolymers or lactic acid polymers and copolymers.
[0005] Since the time of their conception, barbed sutures, which
are generally of the same materials as conventional sutures, have
offered numerous advantages over closing wounds with conventional
sutures. A barbed suture includes an elongated body that has one
or more spaced barbs, which project from the body surface along
the body length. The barbs are arranged to allow passage of the
barbed suture in one direction through tissue but resist movement
of the barbed suture in the opposite direction. Thus, the main advantage
of barbed sutures has been the provision of a non-slip attribute.
Accordingly, barbed sutures do not have to be knotted, like conventional
sutures. Like a conventional suture, a barbed suture may be inserted
into tissue using a surgical needle.
[0006] For instance, U.S. Pat. No. 3123077 to Alcamo describes
an elongated cord for sewing human flesh, where the cord has a body
portion and sharp-edged, resilient barbs projecting from the body
at acute angles relative to the body. The barbed suture can be passed
through tissue in one direction, but resists movement in the opposite
direction.
[0007] Sutures with barbs disposed in a bi-directional arrangement,
also called double-armed sutures, are shown in U.S. Pat. No. 5931855
to Buncke and U.S. Pat. No. 6241747 to Ruff. More particularly,
the suture has barbs facing toward one end of the suture for about
half the suture length and barbs facing in the opposite direction
toward the other end of the suture for the other half of the suture
length. This arrangement allows the barbs to move in the same direction
as each respective suture end is inserted into the first and second
sides of a wound. Such bi-directional barbed sutures not only are
especially suitable for closing wounds with edges prone to separation,
but also obviate the need to secure suture ends together with knotted
loops.
[0008] Of interest is European Published Patent Application No.
1075843 A1 to Sulamanidze and Mikhailov, published Feb. 2 2001
derived from PCT/RU99/00263 (published as WO 00/51658 on Sep. 8
2000), priority to RU 99103732 (Mar. 3 1999), which shows conical
barbs arranged sequentially along the length of a thread and oriented
in a direction opposite to that of the thread tension, with the
distance between barbs being not less than 1.5 times the thread
diameter.
[0009] Also of interest is U.S. Pat. No. 5342376 to Ruff. This
patent shows an insertion device that is useful for positioning
a barbed suture in order to close a wound. The insertion device
has a tubular body for receiving a barbed suture, and preferably
also has a handle to facilitate manipulation of the device by the
surgeon. The insertion device is recommended for use with a barbed
suture where the suture portion being inserted includes barbs facing
a direction opposed to the direction of insertion. Such sutures
with barbs opposing the direction of insertion are also shown in
'376 to Ruff.
[0010] The disclosures of all patents and patent applications mentioned
here are incorporated by reference.
[0011] Escarpment of barbs into a monofilament, depending on the
barb cut depth, reduces the straight pull tensile strength since
the effective suture diameter is decreased. However, the straight
pull tensile strength of a barbed suture should be compared to the
minimum knot pull strength of a conventional suture (a non-barbed
suture) in accordance with the United States Pharmacopoeia since
failure of conventional sutures (which have to be knotted and must
meet a minimum knot pull tensile strength) occurs most frequently
at the knot due to increased local stress.
[0012] To optimize the performance of a barbed suture, it is advantageous
to consider varying the barb geometry (barb cut angle, barb cut
depth, barb cut length, barb cut distance, etc.) and/or the spatial
arrangement of the barbs. This should not only enhance the tensile
strength of a barbed suture, but also should enhance the ability
of a barbed suture in holding and maintaining wound edges together.
Unlike conventional sutures, which place tensions directly at the
knots, barbed sutures can spread out the tension along the escarped
suture length, often evenly along the length. Optimizing the disposition
and/or the configuration of the barbs should therefore further increase
the effectiveness of the new barbed suture in maximizing the holding
strength and minimizing the gap formation along the wound edges.
The latter is particularly beneficial for promoting wound healing.
[0013] Also, such new barbed sutures should approximate tissue
quickly with appropriate tension, alleviate distortion of tissue,
and help to minimize scarring, due to the self-retaining benefits
imparted by the barbs. The new barbed sutures would be especially
useful in surgeries where minimization of scarring is imperative,
such as cosmetic surgery, as well as in surgeries where space is
limited, such as endoscopic surgery or microsurgery.
SUMMARY OF THE INVENTION
[0014] Accordingly, the present invention provides a barbed suture
for connecting human or animal tissue. The barbed suture comprises
an elongated body having a first end and a second end. The barbed
suture further comprises a plurality of barbs projecting from the
body. Each barb is adapted for enabling the barbed suture to resist
movement, when in tissue, in the direction that is opposite from
the direction in which that barb faces. The barbed suture further
comprises the barbs being disposed on the body in a disposition
selected from a staggered disposition, a twist cut multiple spiral
disposition, an overlapping disposition, a random disposition, or
combinations thereof.
[0015] For the staggered disposition, the twist cut multiple spiral
disposition, and/or the overlapping disposition, the barbs may all
be facing toward only one of the first and second ends. Alternatively,
the barbed suture may have at least a first portion and a second
portion, where the barbs of the first portion are facing toward
the first end and the barbs of the second portion are facing toward
the second end.
[0016] Also, in an alternative embodiment, the present invention
provides a barbed suture for connecting human or animal tissue,
where the suture comprises an elongated body having a first end
and a second end. The suture further comprises a plurality of barbs
projecting from the body. Each barb is adapted for enabling the
suture to resist movement, when the suture is in tissue, in the
direction that is opposite from the direction in which that barb
faces. The suture further comprises the barbs having a configuration
selected from a barb cut angle .theta. ranging from about 140 degrees
to about 175 degrees, a barb cut depth with a ratio of cut depth
to suture diameter ranging from about 0.05 to about 0.6 a barb
cut length with a ratio of cut length to suture diameter ranging
from about 0.2 to about 2 a barb cut distance with a ratio of cut
distance to suture diameter ranging from about 0.1 to about 6 a
corrugated underside, an arcuate base, varying sizes, or combinations
thereof.
[0017] For the twist cut multiple spiral disposition, the barbed
suture preferably has a spirality .alpha. angle ranging from about
5 degrees to about 25 degrees.
[0018] For the overlapping disposition, it is meant that at least
two adjacent barbs are disposed where one overlaps the other. During
escarpment of the barbs, the overlapping is created by a barb (i.e.,
the overlapping barb) being escarped into the topside of another
adjacent barb (i.e., the overlapped barb), and so on. Hence, part
of the topside of the overlapped barb becomes part of the underside
of the overlapping barb, and so on. Thus, with the overlapping disposition,
the barb cut distance between the overlapping barb and the overlapped
barb may be shorter than the barb cut length of overlapped second
barb, whereas, in general for barbed sutures, the barb cut distance
between two barbs.gtoreq.the barb cut length.
[0019] In still another embodiment, the present invention provides
a barbed suture for connecting human or animal tissue in combination
with a surgical needle, where the combination comprises a barbed
suture attached to a surgical needle. The suture comprises a plurality
of barbs projecting from an elongated body having a first end and
a second end. Each barb is adapted for enabling the suture to resist
movement, when the suture is in tissue, in the direction that is
opposite from the direction in which that barb faces. The ratio
of the surgical needle diameter to the suture diameter preferably
is about 3:1 or less. Suitably, any of the inventive barbed sutures
described here may be attached to a surgical needle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A is a side view of one embodiment of the present
invention, showing a barbed suture with barbs disposed in a 180
degree staggered spacing;
[0021] FIG. 1B is a sectional view along line 1B-1B of the barbed
suture in FIG. 1A;
[0022] FIG. 2A is a side view of another embodiment of the present
invention, showing a barbed suture that is bi-directional with barbs
disposed in a 180 degree staggered spacing;
[0023] FIG. 2B is a sectional view along line 2B-2B of the barbed
suture in FIG. 2A;
[0024] FIG. 3A is a side view of another embodiment of the present
invention, showing a barbed suture with barbs disposed in a 120
degree staggered spacing;
[0025] FIG. 3B is a sectional view along line 3B-3B of the barbed
suture in FIG. 3A;
[0026] FIG. 4A is a side view of another embodiment of the present
invention, showing a barbed suture that is bi-directional with barbs
disposed in a 120 degree staggered spacing;
[0027] FIG. 4B is a sectional view along line 4B-4B of the barbed
suture in FIG. 4A;
[0028] FIG. 5A is a side view of another embodiment of the present
invention, showing a barbed suture with barbs disposed in a twist
cut multiple spiral disposition;
[0029] FIG. 5B is a sectional view along line 5B-5B of the barbed
suture in FIG. 5A;
[0030] FIG. 6A is a side view of another embodiment of the present
invention, showing a barbed suture that is bi-directional with barbs
disposed in a twist cut multiple spiral disposition;
[0031] FIG. 6B is a sectional view along line 6B-6B of the barbed
suture in FIG. 6A;
[0032] FIG. 7A is a sectional side view of a barbed suture, which
is bi-directional with barbs disposed in a twist cut multiple spiral
disposition like the barbed suture in FIG. 6A, but illustrated in
an enlarged section;
[0033] FIG. 7B is the sectional side view as illustrated in FIG.
7A, but rotated and clamped to align the barbs for measurement of
the cut distance between the barbs;
[0034] FIG. 8 is a side view of another embodiment of the present
invention, showing a barbed suture with barbs in a random disposition;
[0035] FIG. 9 is a sectional side view of another embodiment of
the present invention, showing a barbed suture having a barb with
a corrugated or serrated underside;
[0036] FIG. 10A is a sectional perspective view another embodiment
of the present invention, showing a barbed suture having a barb
with an arcuate base;
[0037] FIG. 10B is a sectional top plan view of the barbed suture
in FIG. 10A;
[0038] FIG. 10C is a cross-sectional view along line 10C-10C of
FIG. 10B;
[0039] FIG. 10D is a cross-sectional view along line 10D-10D of
FIG. 10B;
[0040] FIG. 11 is a sectional side view of another embodiment of
the present invention, showing a barbed suture with barbs of various
sizes;
[0041] FIG. 12A is a sectional perspective view of another embodiment
of the present invention, showing a barbed suture with barbs in
an overlapping disposition;
[0042] FIG. 12B is a perspective view of a portion of the overlapping
barbs of the suture of FIG. 12A;
[0043] FIG. 12C is a plan view of the portion of barbs of FIG.
12B;
[0044] FIG. 12D is a side view along line 12D-12D of FIG. 12C;
and
[0045] FIGS. 13A, 13B, 13C, and 13D show various surgical needles,
where a barbed suture is attached to each surgical needle.
[0046] FIGS. 14A, 14B, 14C, and 14D show various surgical needles,
where a barbed suture is attached to each surgical needle by shrink
wrapping.
[0047] FIGS. 15A, 15B, 15C, and 15D show various surgical needles,
where a barbed suture is attached to each surgical needle by channel
wrapping.
[0048] FIGS. 16A, 16B, 16C, and 16D show various surgical needles,
where a barbed suture is attached to each surgical needle by eyelet
threading.
DESCRIPTION
[0049] As used here, the term "wound" means a surgical
incision, cut, laceration, severed tissue or accidental wound in
human or animal skin or other human or animal bodily tissue, or
other condition in a human or animal where suturing, stapling, or
the use of another tissue connecting device may be required.
[0050] Also as used here, the term "tissue" includes,
but is not limited to, tissues such as skin, fat, fascia, bone,
muscle, organs, nerves, or blood vessels, or fibrous tissues such
as tendons or ligaments.
[0051] Moreover, the term "polymer" as used here generally
includes, but is not limited to, homopolymers, copolymers (such
as block, graft, random and alternating copolymers), terpolymers,
et cetera, and blends and modifications thereof. Furthermore, the
term "polymer" shall include all possible structures of
the material. These structures include, but are not limited to,
isotactic, syndiotactic, and random symmetries.
[0052] Although the sutures are described below in a preferred
embodiment with a circular cross section, the sutures could also
have a non-circular cross sectional shape that could increase the
surface area and facilitate the formation of the barbs. Other cross
sectional shapes may include, but are not limited to, oval, triangle,
square, parallelepiped, trapezoid, rhomboid, pentagon, hexagon,
cruciform, and the like. Typically, barbs are cut into a polymeric
filament that has been formed by extrusion using a die with a circular
cross section, and thus, the cross section of the filament will
be circular, as that is what results during such extrusion. However,
extrusion dies can be custom made with any desired cross-sectional
shape.
[0053] Hence, the term "diameter" as used here is intended
to mean the transverse length of the cross section, regardless of
whether the cross section is circular or some other shape.
[0054] Suitable diameters for the inventive sutures described below
may range from about 0.001 mm to about 1 mm, and of course, the
diameter may be from about 0.01 mm to about 0.9 mm, or from about
0.015 mm to about 0.8 mm. The typical diameter ranges from about
0.01 mm to about 0.5 mm. The length of the suture can vary depending
on several factors such as the length and/or depth of the wound
to be closed, the type of tissue to be joined, the location of the
wound, and the like. Typical suture lengths range from about 1 cm
to about 30 cm, more particularly from about 2 cm to about 22 cm.
[0055] The terms "staggered" and "staggering"
as used here in relation to the disposition of barbs on a suture
are intended to mean that the suture has at least two sets of barbs
that are offset with respect to each other, where the first set
is aligned longitudinally on the suture and the second set is aligned
longitudinally on the suture, but a plane perpendicular to the suture
and cutting transversely through the suture and intersecting the
base of a barb of the first set will not intersect the base of a
barb of the second set.
[0056] The barbs project from the exterior surface of the suture
body on which the barbs are disposed. Depending on the intended
end use of the barbed suture, barbs of different sizes may be employed.
In general, larger barbs are more suitable for joining certain types
of tissue such as fat tissue or soft tissue. On the other hand,
smaller barbs are more suitable for joining other types of tissue,
such as collagen dense tissue.
[0057] As noted above, barbed sutures may be made from the same
materials used for making conventional loop sutures. Any particular
chosen material for the barbed suture depends on the strength and
flexibility requirements.
[0058] More specifically, barbed sutures may be formed from a bio-absorbable
material that allows the suture to degrade and thus to be absorbed
over time into the tissue as the wound heals. Generally, bio-absorbable
materials are polymeric, and depending on the particular polymer
selected, the degradation time in the wound ranges from about 1
month to over 24 months. The use of bio-absorbable materials eliminates
the necessity of removing the sutures from the patient.
[0059] Various bio-absorbable polymers include, but are not limited
to, polydioxanone, polylactide, polyglycolide, polycaprolactone,
and copolymers thereof. Commercially available examples are polydioxanone
(sold as PDS II, a trade name used by Ethicon for selling surgical
sutures), copolymer of about 67% glycolide and about 33% trimethylene
carbonate (sold as MAXON.RTM., a trademark registered to American
Cyanamid for surgical sutures), and copolymer of about 75% glycolide
and about 25% caprolactone (sold as MONOCRYL.RTM., a trademark registered
to Johnson &Johnson for sutures and suture needles). Barbed
sutures made from such bio-absorbable materials are useful in a
wide range of applications.
[0060] Additionally, barbed sutures may be formed from a non-absorbable
material, which may be a polymer. Such polymers include, but are
not limited to, polypropylene, polyamide (also known as nylon),
polyester (such as polyethylene terephthlate, abbreviated here as
PET), polytetrafluoroethylene (such as expanded polytetrafluoroethylene,
abbreviated here as ePTFE and sold by Gore as GOR-TEX.RTM.), polyether-ester
(such as polybutester, which is the condensation polymerization
of dimethyl terephthlate, polytetramethylene ether glycol, and 14-butanediol,
and which is marketed by Davis & Geck and by U.S. Surgical,
companies owned by Tyco, under the name NOVAFIL.RTM., which is a
trademark registered to American Cyanamid for surgical sutures),
or polyurethane. Alternatively, the non-absorbable material may
be metal (e.g., steel), metal alloys, natural fiber (e.g., silk,
cotton, et cetera), and the like.
[0061] Most of the barbed sutures discussed below are described
as having their ends being pointed and formed of a material sufficiently
stiff to allow for piercing tissue. It is contemplated that the
ends of the barbed sutures may comprise a surgical needle. In this
embodiment, the barbed suture is adapted for attachment, such as
by swaging, channel wrapping, heat shrinking, or eyelet threading
to the surgical needle for insertion into tissue.
[0062] Attachment by swaging is well described and is typically
accomplished by inserting the suture end into the surgical needle
hole that is longitudinally disposed at one end of the surgical
needle (usually the hole has been drilled longitudinally into one
end of the needle), followed by crimping the resultant about the
needle hole so that the suture is secured to the surgical needle
for insertion into tissue. Also, some surgical needles with a longitudinal
hole in one end are heat-shrinkable tubes that are heat shrunk after
insertion of the suture in order to attach the suture to the surgical
needle. Additionally, some surgical needles have a channel or trough
at one end, and the suture is laid in the trough, followed by wrapping
to secure the suture to the surgical needle. Surgical needles with
a conventional eyelet type of hole transversely disposed in one
end of the surgical needle could also be used, but are not preferred
for barbed sutures. For the present invention, part of the discussion
below regards surgical needles swaged with barbed sutures, but it
is contemplated that any other suitable means of attaching needles
can be employed.
[0063] Attachment of sutures and surgical needles is described
in U.S. Pat. No. 3981307 Borysko, U.S. Pat. No. 5084063 to Korthoff,
U.S. Pat. No. 5102418 to Granger et al., U.S. Pat. No. 5123911
to Granger et al., U.S. Pat. No. 5500991 to Demarest et al., U.S.
Pat. No. 5722991 to Colligan, U.S. Pat. No. 6012216 to Esteves
et al., and U.S. Pat. No. 6163948 to Esteves et al. A method for
the manufacture of surgical needles is described in U.S. Pat. No.
5533982 to Rizk et al. Further, it is noted that the surgical
needle may be coated, the coating allowing for the needle of the
inventive combination surgical needle/barbed suture to be inserted
into tissue with less force than if the surgical needle were not
coated. The coating may be a polymer, for instance, a silicone resin
coating. For example, an improved siliconized surgical needle that
requires significantly less force to effect tissue penetration than
a standard siliconized surgical needle is described in U.S. Pat.
No. 5258013 to Granger et al.
[0064] The barbs are disposed in various arrangements on the body
of the suture. The barbs may be formed using any suitable method,
including injection molding, stamping, cutting, laser, and the like.
With regard to cutting, in general, polymeric threads or filaments
are purchased, and then the barbs are cut onto the filament body.
[0065] The cutting may be manual, but that is labor intensive and
not cost effective.
[0066] A very suitable cutting machine is disclosed in U.S. patent
application Ser. No. 09/943733 to Genova et al., assignors to Quill
Medical, filed Aug. 31 2001 the disclosure of which is incorporated
by reference. Such a cutting machine has a plurality of blades for
escarpment of barbs onto a suture filament. A typical cutting machine
for manufacturing barbed sutures utilizes a cutting bed, a vise,
one or more blade assemblies, and sometimes a template or guide
for the blades. The suture filament is placed in the bed and held
by the vise, with the transverse direction of the blades generally
disposed in the transverse direction of the suture filament, in
order to cut a plurality of axially spaced barbs disposed on the
exterior of a suture filament.
[0067] With reference now to the drawings, where like reference
numerals designate corresponding or similar elements throughout
the several views, shown in FIG. 1A is a side view of a barbed suture
according to the present invention and generally designated at 1.
[0068] Suture 1 includes elongated body 2 that is generally circular
in cross section and that terminates in end 4. End 4 is illustrated
in one embodiment as being pointed for penetrating tissue, but it
is contemplated that end 4 may comprise a surgical needle (not shown)
for insertion into tissue. (The other end is not shown.) Also, suture
1 includes plurality of closely spaced barbs 7 9 arranged in a
staggered unidirectional disposition. More specifically, axially
spaced barbs 7 are radially arranged about 180 degrees from and
staggered with respect to axially spaced barbs 9 with barbs 7
9 facing pointed end 4. First set of barbs 7 define a plane that
is substantially coplanar with the plane defined by second set of
barbs 9 and consequently, barbs 7 9 define substantially the same
one plane due to the radial 180 degree arrangement.
[0069] FIG. 1B, which is a cross sectional view along line 1B-1B
of suture 1 in FIG. 1A, more clearly illustrates angle X, namely
the radial 180 degree arrangement of barbs 7 with respect to barbs
9. As also can be seen from FIG. 1B, the stippling illustrates that
first barb 7 of barbs 7 is closer to pointed end 4 (not shown in
FIG. 1B), and thus, seems to be larger than farther away first barb
9 of barbs 9 due to the staggering. A transverse plane that is
perpendicular to suture body 2 and that intersects the base of one
barb 7 of barbs 7 does not intersect the base of any barb 9 of barbs
9.
[0070] Suture 1 may be made with a cutting machine that produces
two sets of barbs 7 9 usually one set at a time, in a staggered
position along suture 1 such as the cutting device described in
the above-noted Ser. No. 09/943733 to Genova et al. First set of
barbs 7 is created by placing and holding a suture filament in the
vise, and then, the set of blades, with a predetermined length,
splices into the suture filament at an angle selected to create
barbs 7 pointing in one direction toward pointed end 4. Second set
of barbs 9 is created similarly after offsetting the blades longitudinally
(to create the staggering) approximately half of the longitudinal
distance between two of barbs 7 and also rotating the suture filament
about 180 degrees on the vise, which is equipped to accommodate
first set of barbs 7 that are already cut.
[0071] Shown in FIG. 2A is suture 10 which is another embodiment
of the present invention and is like suture 1 except that suture
10 is bi-directional. Suture 10 includes elongated body 12 that
is generally circular in cross section. Elongated body 12 terminates
in first and second pointed ends 14 16 for penetrating tissue.
Also, it is contemplated that one or both ends 14 16 may comprise
a surgical needle (not shown) for insertion into tissue. Also, suture
10 includes plurality of closely spaced barbs 17 18 19 20 arranged
in a staggered bi-directional disposition.
[0072] More specifically, plurality of axially spaced barbs 17
are radially arranged about 180 degrees from and staggered with
respect to plurality of axially spaced barbs 19 with barbs 17
19 facing pointed end 14 for a portion (about half of the length)
of suture 10. Similarly, plurality of axially spaced barbs 18 are
radially arranged about 180 degrees from and staggered with respect
to plurality of axially spaced barbs 20 with barbs 18 20 facing
pointed end 16 for another portion (approximately the other half
of the length) of suture 10. First set of barbs 17 18 define a
plane that is substantially coplanar with the plane defined by second
set of barbs 19 20. As a result, all of barbs 17 18 19 20 define
substantially the same one plane due to the radial 180 degree arrangement
of first set of barbs 17 18 with respect to second set of barbs
19 20.
[0073] FIG. 2B is a cross sectional view along line 2B-2B of suture
10 in FIG. 2A, more clearly illustrating angle X, namely the radial
180 degree arrangement. Due to the staggering, first barb 17 of
barbs 17 is closer to pointed end 14 (not shown in FIG. 2B), and
thus, appears larger than farther away first barb 19 of barbs 19
as is illustrated by the stippling. A transverse plane that is perpendicular
to suture body 12 and that intersects the base of one barb 17 of
barbs 17 does not intersect the base of any barb 19 of barbs 19.
Likewise, a transverse plane that is perpendicular to suture body
12 and that intersects the base of one barb 18 of barbs 18 does
not intersect the base of any barb 20 of barbs 20.
[0074] Suture 10 may be made with the same cutting machine as suture
1 such as the cutting device described in the above-noted Ser.
No. 09/943733 to Genova et al., except with the following change
in blade direction.
[0075] For first set of bi-directional barbs 17 18 after the
suture filament is placed and held in the vise, the blades splice
with a first cutting action into approximately half of the length
of the suture filament to create barbs 17 facing in one direction
toward pointed end 14. Next, the blades are rotated 180 degrees
so that they are now disposed in the opposite direction and over
the uncut half of the length. The blades are then allowed to splice
into the other half of the length of the suture filament with a
second cutting action to create barbs 18 facing in the opposite
direction toward pointed end 16.
[0076] Next, the blades are offset longitudinally (to create the
staggering) about half of the longitudinal distance between two
of barbs 17 and also the suture filament is rotated about 180 degrees
on the vice, which is equipped to accommodate first set of bi-directional
barbs 17 18 that are already cut. Then, for second set of bi-directional
barbs 19 20 the blades splice with a first cutting action into
approximately half the length of the suture filament to create barbs
20 facing in one direction toward pointed end 16. The first cutting
action is followed by rotating the blades longitudinally 180 degrees
so that they are now disposed in the opposite direction and over
the uncut half of the length. The blades are then allowed to splice
into the other half of the length of the suture filament with a
second cutting action to create barbs 19 facing in the opposite
direction toward pointed end 14.
[0077] In an alternative embodiment (not shown) for bi-directional
suture 10 the portion of suture 10 with barbs 17 19 may have them
facing toward pointed end 16 and the portion of suture 10 with barbs
18 20 may have them facing toward pointed end 14. With this variation,
the barbed suture would be inserted into tissue with an insertion
device, such as that shown in the above-noted U.S. Pat. No. 5342376
to Ruff. Additionally, it is noted that, if desired, barbs may be
escarped so that there may be two portions with barbs facing one
end and one portion with barbs facing the other end, or two portions
with barbs facing one end and two portions with barbs facing the
other end, and so on (not shown), and thus, if a portion of barbs
is not facing the suture end to which those barbs are adjacent,
then, the barbed suture would be inserted into tissue with an insertion
device.
[0078] An advantage of a barbed suture having a radial 180 degree
arrangement with staggering is that the 180 degree spacing is readily
fabricated on relatively small diameter filaments and the staggering
improves anchoring performance. Thus, in thin and delicate tissue,
where a smaller suture is desirable, the staggered 180 degree spacing
generates effective anchoring performance.
[0079] Turning now to FIG. 3A, depicted is a side view of another
embodiment of a suture according to the present invention, and generally
designated at suture 30. Suture 30 is like suture 1 shown in FIG.
1A, except that the radial spacing for suture 30 is 120 degrees
instead of 180 degrees as is shown for suture 1.
[0080] More particularly, suture 30 includes elongated body 32
that is generally circular in cross section and that terminates
in pointed end 34 for penetrating tissue. It is contemplated that
end 34 may comprise a surgical needle (not shown) so that the suture
can be inserted into tissue. (The other end is not shown.) Additionally,
suture 30 includes plurality of closely spaced barbs 35 37 39
arranged so that all face in the same direction toward pointed end
34. Hence, the disposition of barbs 35 37 39 is uni-directional.
[0081] Also, axial spaced barbs 35 are radially arranged about
120 degrees from and staggered with respect to axially spaced barbs
37 which are radially arranged about 120 degrees from and staggered
with respect to axially spaced barbs 39. Hence, axially spaced barbs
39 are also arranged about 120 degrees from and staggered with respect
to axially spaced barbs 35. As a result of the radial 120 degree
arrangement, first set of barbs 35 define substantially the same
one plane; second set of barbs 37 define substantially another same
one plane; and third set of barbs 39 define substantially still
another same one plane. Thus, suture 30 has barbs 35 37 39 arranged
in a staggered uni-directional 120 degree disposition.
[0082] FIG. 3B is a cross sectional view along line 3B-3B of suture
30 in FIG. 3A and shows with more particularity angle Y, namely
the radial 120 degree arrangement of barbs 35 with respect to barbs
37 barbs 37 with respect to barbs 39 and barbs 39 with respect
to barbs 35.
[0083] As illustrated by the stippling, first barb 35 of barbs
35 because of the staggering, is closer to pointed end 34 (not
shown in FIG. 3B), and thus, seems to be larger than farther away
first barb 37 of barbs 37. Also, first barb 37 of barbs 37 due
to the staggering, is closer to pointed end 34 (not shown in FIG.
3B), and thus, seems to be larger than even farther away first barb
39 of barbs 39. A transverse plane that is perpendicular to suture
body 32 and that intersects the base of one barb 35 of barbs 35
does not intersect the base of any barb 37 of barbs 37. Likewise,
a transverse plane that is perpendicular to suture body 32 and that
intersects the base of one barb 37 of barbs 37 does not intersect
the base of any barb 39 of barbs 39. Similarly, a transverse plane
that is perpendicular to suture body 32 and that intersects the
base of one barb 39 of barbs 39 does not intersect the base of any
barb 35 of barbs 35.
[0084] Suture 30 may be made with the same cutting machine as suture
1 such as the cutting device described in the above-noted Ser.
No. 09/943733 to Genova et al. The cutting machine is now used
to produce three sets of barbs 35 37 39 usually one set at a
time, in a staggered position along suture 30.
[0085] First set of barbs 35 is created by placing and holding
a suture filament in the vise, followed by the blades, after having
been adjusted to a predetermined length, splicing into the suture
filament at an angle that is chosen to create barbs 35 so that all
are facing in the same direction toward pointed end 34.
[0086] Next, the blades are offset longitudinally (to create the
staggering) approximately half of the longitudinal distance between
two of barbs 35. Also, the filament is rotated about 120 degrees
on the vise, which is equipped to accommodate first set of barbs
35 that have already been cut, and then second set of barbs 37 is
created in a similar manner.
[0087] Likewise, the blades are again offset longitudinally (to
create the staggering) approximately half the longitudinal distance
between two of barbs 35 and also the suture filament is rotated
about 120 degrees on the vise, which is equipped to accommodate
both already cut first set of barbs 35 and already cut second set
of barbs 37. Following the longitudinal movement and rotation, third
set of barbs 39 is created in a similar manner.
[0088] Preferably, each successive barb is escarped at a position
about 120 degrees around suture body 32 from the preceding barb
and does not overlap with any other barb.
[0089] With reference now to FIG. 4A, illustrated is suture 40
another embodiment of the present invention. Suture 40 is similar
to suture 30 except that suture 40 is bi-directional. Suture 40
includes elongated body 42 that is generally circular in cross section
and that terminates in first and second pointed ends 44 46 for
penetrating tissue. Also, it is contemplated that one or both ends
44 46 may comprise a surgical needle (not shown) in order to be
inserted into tissue. Suture 40 further includes plurality of closely
spaced barbs 47 48 49 50 51 52 arranged in a staggered bi-directional
disposition.
[0090] For about half of the length of suture 40 axially spaced
barbs 47 are circumferentially arranged about 120 degrees from and
staggered with respect to axially spaced barbs 49 which are radially
arranged about 120 degrees from and staggered with respect to axially
spaced barbs 51. Consequently, axially spaced barbs 51 are also
arranged about 120 degrees from and staggered with respect to axially
spaced barbs 47. Thus, a portion of suture 40 has all of barbs 47
49 51 facing in the same direction toward pointed end 44.
[0091] For the other half of the length of suture 40 axially spaced
barbs 48 are radially arranged about 120 degrees from and staggered
with respect to axially spaced barbs 50 which are radially arranged
about 120 degrees from and staggered with respect to axially spaced
barbs 52. Consequently, axially spaced barbs 52 are also arranged
about 120 degrees from and staggered with respect to axially spaced
barbs 48. Thus, another portion of suture 40 has all of barbs 48
50 52 facing in the same direction toward pointed end 46.
[0092] As a result of the radial 120 degree arrangement, first
set of barbs 47 48 define substantially the same one plane; second
set of barbs 49 50 define substantially another same one plane;
and third set of barbs 51 52 define substantially still another
same one plane.
[0093] FIG. 4B, which is a cross sectional view along line 4B-4B
of suture 40 in FIG. 4A, shows more clearly angle Y, namely the
radial 120 arrangement with greater specificity. As illustrated
by the stippling, first barb 47 of barbs 47 on account of the staggering,
is closer to pointed end 44 (not shown in FIG. 4B), and thus, appears
larger than farther away first barb 49 of barbs 49. Also because
of the staggering, first barb 49 of barbs 49 is closer to pointed
end 44 (not shown in FIG. 4B), and thus, appears larger than even
farther away first barb 51 of barbs 51.
[0094] A transverse plane that is perpendicular to suture body
42 and that intersects the base of one barb 47 of barbs 47 does
not intersect the base of any barb 49 of barbs 49. Likewise, a transverse
plane that is perpendicular to suture body 32 and that intersects
the base of one barb 49 of barbs 49 does not intersect the base
of any barb 51 of barbs 51. Similarly, a transverse plane that is
perpendicular to suture body 42 and that intersects the base of
one barb 51 of barbs 51 does not intersect the base of any barb
47 of barbs 47. Also, a transverse plane that is perpendicular to
suture body 42 and that intersects the base of one barb 48 of barbs
48 does not intersect the base of any barb 50 of barbs 50. Likewise,
a transverse plane that is perpendicular to suture body 32 and that
intersects the base of one barb 50 of barbs 50 does not intersect
the base of any barb 52 of barbs 52. Similarly, a transverse plane
that is perpendicular to suture body 42 and that intersects the
base of one barb 52 of barbs 52 does not intersect the base of any
barb 48 of barbs 48.
[0095] Suture 40 may be made with the same cutting machine as suture
1 such as the cutting device described in the above-noted Ser.
No. 09/943733 to Genova et al., except with the following change
in blade direction.
[0096] For first set of bi-directional barbs 47 48 after the
suture filament is placed and held in the vise, the blades splice
with a first cutting action into approximately half of the length
of the suture filament to create barbs 47 facing in one direction
toward pointed end 44. Then, the blades are rotated 180 degrees
so that they are now disposed in the opposite direction and over
the uncut half of the length. The blades then are allowed to splice
into the other half of the length of the suture filament with a
second cutting action to create barbs 48 facing in the opposite
direction toward pointed end 46.
[0097] Next, the blades are offset longitudinally (to create the
staggering) for about half the longitudinal distance between two
of barbs 47 and also the suture filament is rotated about 120 degrees
on the vise, which is equipped to accommodate first set of bi-directional
barbs 47 48 that are already cut. Then, for second set of bi-directional
barbs 49 50 the blades splice with a first cutting action into
approximately half of the length of the suture filament to create
barbs 50 facing in one direction toward pointed end 46. The first
cutting action is followed by rotating the blades 180 degrees so
that they are now disposed in the opposite direction and over the
uncut half of the suture filament. They then splice into the other
half of the length of the suture filament with a second cutting
action to create barbs 49 facing in the opposite direction toward
pointed end 44.
[0098] Then, the blades are again offset longitudinally (to create
the staggering) for about half the longitudinal distance between
two of barbs 47. Additionally, the suture filament again is rotated
about 120 degrees on the vise, which is equipped to accommodate
already cut first set of bi-directional barbs 47 48 and already
cut second set of bi-directional barbs 49 50. Following the longitudinal
movement and rotation, the third set of bi-directional barbs 51
52 are made by having the blades splice with a first cutting action
into approximately half of the length of the suture filament to
create barbs 51 facing in one direction toward pointed end 44. The
first cutting action is followed by rotating the blades 180 degrees
so that they are now disposed in the opposite direction and over
the uncut half of the suture filament. They next splice into the
other half of the length of the suture filament with a second cutting
action to create barbs 52 facing in the opposite direction toward
pointed end 46.
[0099] Preferably, each successive barb is escarped at a position
about 120 degrees around suture body 42 from the preceding barb
and does not overlap with any other barb.
[0100] In an alternative embodiment (not shown) for bi-directional
suture 40 the portion of suture 40 having barbs 47 49 51 may
have them facing toward pointed end 46 and the portion of suture
40 having barbs 48 50 52 may have them facing toward pointed end
44. With this variation, the barbed suture would be inserted into
tissue with an insertion device, such as that shown in the above-noted
U.S. Pat. No. 5342376 to Ruff. Additionally, it is noted that,
if desired, barbs may be escarped so that there may be two portions
with barbs facing one end and one portion with barbs facing the
other end, or two portions with barbs facing one end and two portions
with barbs facing the other end, and so on (not shown), and thus,
if a portion of barbs is not facing the suture end that those barbs
are adjacent, then, the barbed suture would be inserted into tissue
with an insertion device.
[0101] An advantage of a barbed suture with a radial 120 degree
arrangement is that the barbs exert force in three distinct planes
that compliment each other, resulting in maximization of the retention
force of the suture overall. As noted above, the staggering enhances
anchoring performance.
[0102] Turning now to FIG. 5A, shown is another embodiment of the
present invention, which is generally designated at suture 60 with
radial spacing that is in a twist cut multiple spiral. Suture 60
includes elongated body 62 of generally circular cross section.
Elongated body 62 terminates in pointed end 64 for penetrating tissue.
Also, it is contemplated that end 64 may comprise a surgical needle
(not shown) for insertion into tissue. Furthermore, suture 60 includes
plurality of closely spaced barbs 67 arranged in a twist cut multiple
spiral pattern around body 62 and facing in the same direction toward
pointed end 64.
[0103] FIG. 5B is a cross sectional view along line 5B-5B of suture
60 in FIG. 5A. Due to the twist cut multiple spiral disposition,
each respective barb 67 seems to be smaller and smaller as each
is farther and farther away from pointed end 64 (not shown in FIG.
5B), the illusion of size difference being illustrated by the stippling.
[0104] Suture 60 may be constructed with a similar cutting machine
as that used for making suture 1 such as the cutting device described
in the above-noted Ser. No. 09/943733 to Genova et al. With a twist
cutting method, barbs 67 may be produced in multiple spirals that
preferably are created at the same time as the suture filament is
held stationary, instead of being rotated, when the cutting takes
place.
[0105] More particularly, a suture filament that is about 7 inches
(about 178 mm) in length, is longitudinally twisted for a portion
of the suture length, such as 39 times for a portion that is about
4.5 inches (about 114 mm) of the suture length. Thus, an end is
secured, and the other end is grasped and rotated 360 degrees, 39
times, so the portion of the suture filament is twisted when the
suture is then placed and held in the vise.
[0106] Twisting preferably is performed 28 to 50 times, and may
be performed more or less, such as 19 to 70 times. Suitably, twisting
may be from about 2 to about 17 twists per inch, or about 3 to about
15 twists per inch, or about 5 to about 13 twists per inch (per
inch being per 25.4 mm).
[0107] Next, the blades, after having been adjusted to a predetermined
length, simultaneously splice into the suture filament. The cutting
action makes cuts to create barbs 67 so that all are facing in the
same direction toward pointed end 64. After twist cut multiple spiral
barbed suture 60 is released from the vice and untwisted, barbs
67 are disposed in multiple spirals on suture 60.
[0108] Turning now to FIG. 6A, shown is another embodiment of the
present invention, which is generally designated at suture 70. Suture
70 is of a twist cut multiple spiral disposition and thus is similar
to suture 60 except that suture 70 is bi-directional. Suture 70
includes elongated body 72 that is generally circular in cross section
and that terminates in first and second pointed ends 74 76 for
penetrating tissue. It is contemplated that one or both of ends
74 76 may comprise a surgical needle (not shown) for insertion
into tissue.
[0109] Suture 70 further includes plurality of closely spaced barbs
77 78 arranged in two respective spiral patterns, each being a
multiple spiral around body 72. Barbs 77 78 are disposed on middle
portion MP that is approximately 3 inches (approximately 76 mm)
of suture 70 with each end portion EP of suture 70 being barb-free.
More particularly, plurality of barbs 77 are arranged in a multiple
spiral pattern with all barbs 77 facing toward pointed end 74 for
a part (about half) of middle portion MP along the length of suture
70. Similarly, plurality of barbs 78 are arranged in a multiple
spiral pattern with all barbs 78 facing toward pointed end 76 for
another part (the other approximate half) of middle potion MP along
the length of suture 70.
[0110] FIG. 6B is a cross sectional view along line 6B-6B of suture
60 in FIG. 6A. Due to the multiple spiral configuration, each respective
barb 77 seems to be smaller and smaller as each is farther and farther
away from pointed end 74 (not shown in FIG. 6B), as illustrated
by the stippling.
[0111] Suture 70 may be made with the same cutting machine as suture
60 such as the cutting device described in the above-noted Ser.
No. 09/943733 to Genova et al., but with the following change in
blade direction. Using the twist cutting method, barbs 77 may be
produced in multiple spirals that preferably are created at the
same time, and then after the direction change for the blades, barbs
78 may be produced in multiple spirals that preferably are created
at the same time. Thus during the cutting, the suture filament is
held stationary instead of being rotated.
[0112] More specifically, a section of about 4.5 inches (about
114 mm) in length of a suture filament is twisted, such as 39 times
for a suture about 7 inches (about 178 mm) in length. Thus, an end
is secured, and the other end is grasped and rotated 360 degrees,
39 times, so the twisted section of the suture filament has about
82/3 twists per inch (per 25.4 mm) when the suture filament is then
is placed and held in the vise.
[0113] Twisting preferably is performed 28 to 50 times, and may
be performed more or less, such as 19 to 70 times. Suitably, twisting
may be from about 2 to about 17 twists per inch, or about 3 to about
15 twists per inch, or about 5 to about 13 twists per inch (per
inch being per 25.4 mm).
[0114] Next, the blades, after having been adjusted to a predetermined
length, splice into approximately half of the approximately 3 inch
(approximately 76 mm) length of middle portion MP of the approximately
4.5 inch (approximately 114 mm) twisted section of the suture filament
in a first cutting action with the blades making cuts to create
barbs 77 so that all are facing in one direction toward pointed
end 74. Depending on how many blades there are on the cutting machine
and how many barbs 77 are desired, there may be one cutting motion
to cut all barbs 77 simultaneously, or there may be repeated cutting
motions until the desired number of barbs 77 are escarped into a
portion of the suture filament.
[0115] Then, the blades are rotated 180 degrees so that they are
now disposed in the opposite direction and over the other half of
the approximately 3 inch (approximately 76 mm) length of middle
portion MP of the approximately 4.5 inch (approximately 114 mm)
twisted section of the suture filament. The blades are then allowed
to splice into the other half in a second cutting action with the
blades making cuts to create barbs 78 so that all are facing in
the opposite direction toward pointed end 76. Depending on how many
blades there are on the cutting machine and how many barbs 78 are
desired, there may be one cutting motion to cut all barbs 78 simultaneously,
or there may be repeated cutting motions until the desired number
of barbs 78 are escarped into a portion of the suture filament.
[0116] When twist cut multiple spiral barbed suture 70 is released
from the vise and untwisted, the first cuts and the second cuts
result in barbs 77 78 being in two respective multiple spiral patterns
on two respective portions of suture 70 the two respective portions
defining middle portion MP of about 3 inches (about 76 mm) in length.
[0117] More particularly, several twist cut multiple spiral, barbed
sutures were manufactured from a monofilament having a diameter
of about 0.018 inch (about 0.457 mm) and spun from polydioxanone
(which is a synthetic absorbable suture material). A diameter of
about 0.018 inch (about 0.457 mm) is slightly larger than the size
0 synthetic absorbable suture, which has a diameter range from about
0.35 mm to about 0.399 mm in accordance with the specifications
of the United States Pharmacopoeia (USP).
[0118] Each suture contained a total of 78 barbs introduced in
two respective multiple spiral patterns around the circumference
of the suture. Since the barbed suture was bi-directional, the barbs
were divided into a left group with 39 barbs disposed on a first
portion of the suture and a right group with 39 barbs on a second
portion of the suture, each group opposing the direction of the
other group from the approximate middle of the suture. The specific
cutting machine employed had 13 blades. Thus, for each group of
39 barbs, there were 3 cutting motions (3.times.13=39), with the
blades being offset with a guide for each of the 3 cutting motions.
[0119] Each suture was about 7 inches (about 178 mm) long. The
middle portion MP was about 3 inches (about 76 mm) long and contained
the 78 barbs that were escarped into the suture filament. Extending
beyond the 3 inch (76 mm) barbed middle portion MP were two unbarbed
end portions EP of the suture that were each about 2 inches (about
51 mm) long. Depending on the suturing technique, one or both ends
of the barbed suture may be sufficiently pointed and rigid for insertion
into tissue, or may comprise a straight or curved surgical needle.
[0120] The strength of the twist cut, 7 inch (178 mm) barbed sutures
was tested by two methods. One method was a straight pull tensile
strength test with a Universal Tester and the other method was an
in vivo performance test with dogs.
[0121] For the straight pull tensile strength measurement, testing
was performed using a Test Resources Universal Tester, Model 200Q.
The average reading of 10 repeated measurements made for each kind
of suture was recorded for the barbed sutures and for the comparison
unbarbed sutures.
[0122] Comparison unbarbed sutures were polydioxanone monofilaments
(a synthetic absorbable suture material) of various suture diameters
of about 0.018 inch (about 0.457 mm), about 0.015 inch (about 0.381
mm), and about 0.0115 inch (about 0.292 mm), which are respectively
slightly larger than the United States Pharmacopoeia sizes 0 2-0
and 3-0 for synthetic absorbable sutures. In accordance with United
States Pharmacopoeia specifications for synthetic absorbable sutures,
size 0 has a diameter range of about 0.35 mm to about 0.399 mm;
size 2-0 has a diameter range of about 0.30 mm to about 0.339 mm;
and size 3-0 has a diameter range of about 0.20 mm to about 0.249
mm.
[0123] Each barbed suture was gripped at each end by being held
with cork gasket padding in two respective serrated jaws, whereas
each unbarbed suture was gripped at each end by being wrapped around
two respective capstan roller grips. Capstan rollers were used for
holding the unbarbed sutures to avoid stress and distension.
[0124] The portion of each suture specimen between the two gripped
places was about 5 inches (about 126 mm) in length, which, in the
case of barbed sutures, contained the entire 3 inches (76 mm) of
the barbed middle portion.
[0125] Each specimen was pulled longitudinally at a rate of about
10 inches (about 254 mm) per minute until breakage occurred. The
peak load was recorded as the straight pull tensile strength.
[0126] The results are summarized in Table 6A below, and the far
right column denotes the USP knot pull test minimum requirements
for conventional (unbarbed) sutures made from a synthetic absorbable
material. TABLE-US-00001 TABLE 6A (Tensile Strength) USP Minimum
Barbed or Suture Straight Pull Requirements Unbarbed Size (pounds)
for Knot Pull (pounds) Unbarbed 0 17.72 8.60 Unbarbed 2-0 11.86
5.91 Unbarbed 3-0 8.82 3.90 Barbed 0 7.03 not applicable
[0127] As can be seen, escarpment of barbs into the size 0 polydioxanone
monofilament reduced the straight pull tensile strength by approximately
60% as compared to the conventional unbarbed size 0 polydioxanone
monofilament (7.03 pounds=40% of 17.72 pounds).
[0128] However, the straight pull tensile strength of 7.03 pounds
at breakage for the size 0 polydioxanone barbed suture (which, due
to the escarpment of the barbs, has an effective diameter that is
smaller than the diameter of the conventional unbarbed size 0 polydioxanone
suture) compared favorably with the minimum USP knot pull requirement
of 8.60 pounds for the size 0 polydioxanone conventional unbarbed
suture.
[0129] Additional straight pull tensile strength tests were performed
on additional size 0 polydioxanone barbed sutures, as discussed
below in Tables 7K-7Z, in connection with FIGS. 7A and 7B.
[0130] For the in vivo performance, 3 mongrel dogs, each about
14 kg, were used. On each dog, 7 incisions were made at the thorax
(twice), thigh (twice), flank, ventral midline, and paramedian,
each of the 7 incisions having 1 2 or 3 closure sites. The length
of each incision ranged from about 0.5 inch (about 12.5 mm) to about
4 inches (about 101 mm) and the depth of each incision was from
the superficial dermis to the peritoneum.
[0131] Using the barbed sutures (all made from size 0 polydioxanone
monofilament), 24 of the sites were closed. For comparison, the
remaining sites were closed with various diameter sizes of conventional
unbarbed sutures (1 site with size 2-0 silk braided filament, 6
sites with size 2-0 nylon monofilament, and 7 sites with size 3-0
polydioxanone monofilament), which were knotted. All closing of
sites was performed according to a randomized scheme.
[0132] The dogs were monitored daily, and then subjected to euthanasia
at 14 days. At the time of death, the incisions were evaluated macroscopically.
With regard to various tissues, incision sizes, and locations on
the dogs, all sites apposed with the size 0 polydioxanone barbed
sutures stayed closed and appeared to be healing normally throughout
the 14 day observation period. No dehiscence occurred.
[0133] The site apposed with the conventional unbarbed silk sutures
and the sites apposed with the conventional unbarbed polydioxanone
sutures also healed will without complications. No dehiscence occurred.
[0134] For the 6 topical skin sites closed with the size 2-0 nylon
monofilament conventional unbarbed sutures, 3 sites exhibited partial
or complete suture loss, apparently due to self-mutilation by the
dogs. Knots in the conventional sutures possibly caused discomfort
by creating localized pressure, and animals cannot understand that
they should not manipulate the sutures. Thus, barbed sutures should
help obviate the problem of an animal manipulating and pulling out
the sutures.
[0135] In summary, the in vivo performance of the size 0 polydioxanone
barbed sutures was efficacious when compared to the size 2-0 silk
braided filament unbarbed sutures, the size 2-0 nylon monofilament
unbarbed sutures, and the size 3-0 polydioxanone monofilament unbarbed
sutures.
[0136] In an alternative embodiment (not shown) for bi-directional
twist cut, multiple spiral suture 70 the portion of suture 70 on
which is disposed barbs 77 may have barbs 77 facing toward pointed
end 76 and the portion of suture 70 on which is disposed barbs 78
may have barbs 78 facing toward pointed end 74. With this variation,
the barbed suture would be inserted into tissue with an insertion
device, such as that shown in the above-noted U.S. Pat. No. 5342376
to Ruff. Also if desired, it is noted that barbs may be escarped
so that there may be 2 portions with barbs facing an end and 1 portion
with barbs facing the other end, or 2 portions with barbs facing
an end and 2 portions with barbs facing the other end, and so on
(not shown), and thus, if a portion of barbs is not facing the suture
end to which those barbs are adjacent, then, the barbed suture would
be inserted into tissue with an insertion device.
[0137] An advantage of a barbed suture having a twist cut, multiple
spiral disposition is that such a barbed suture affords better wound
holding capability as compared to the 120 degree spaced barbed suture.
The reason is that the twist cut, multiple spiral pattern results
in groups of barbs that complement successive and preceding groups
of barbs, which tends to provide improved anchoring when the suture
is in tissue. This feature is especially useful for tissue such
as fat tissue, which has fewer connective fibers compared with other
types of tissues, so that greater suture retention force is desirable.
[0138] With reference now to FIG. 7A, shown is a sectional side
view of barbed suture 80. Barbed suture 80 has plurality of closely
spaced barbs 81 on elongated suture body 82 of generally circular
cross section. Each barb 81 has barb tip 85. Shown are suture longitudinal
axis A, suture diameter SD, barb length L, barb cut depth D, barb
cut angle .theta., cut distance P, spirality angle .alpha., cut-out
depression CD, and tip T of cut-out depression CD.
[0139] FIG. 7B is the sectional side view as illustrated in FIG.
7A, but rotated and clamped to align the barbs for measurement of
the cut distance P between barbs 81. Barbed suture 80 is a twist
cut, multiple spiral, bi-directional barbed suture, like suture
70 in FIG. 6A, but illustrated as an enlarged section in order to
show more detail with respect to the configuration of barbs 81 vis-a-vis
suture longitudinal axis A, suture diameter SD, barb length L, barb
cut depth D, barb cut angle .theta., cut distance P, spirality angle
.alpha., cut-out depression CD, and terminus T of cut-out depression
CD.
[0140] More specifically, several twist cut, multiple spiral, barbed
sutures were manufactured from monofilament spun from polydioxanone
and having a diameter of about 0.018 inch (about 0.457 mm, which
is slightly more than the USP requirement for a size 0 synthetic
absorbable suture). Each suture contained 78 barbs introduced in
2 separate multiple spiral patterns around the circumference of
the suture. Since the barbs were bi-directional, they were divided
into a left group with 39 barbs and a right group with 39 barbs,
each group opposing the direction of the other group from the approximate
middle of the suture. Each suture was about 7 inches (about 178
mm) long. The middle portion was about 3 inches (about 76 mm) of
the suture and contained the 78 barbs that were escarped into the
suture filament. Extending beyond the 3 inch (76 mm) barbed middle
portion toward each suture end were two unbarbed end portions of
the suture filament that were each about 2 inches (about 51 mm)
long. Depending on the stitching technique, one or both ends of
the barbed suture may be sufficiently pointed and rigid for insertion
into tissue, or may comprise a straight or curved needle.
[0141] In order to characterize the configuration of barbs 81
an Optem Zoom 100 custom microscope with both ring and back lighting
was used together with a CCD brand video camera in order to measure
selected barbs 81 at .times.21.5 magnification from each of the
left and right groups.
[0142] The average was calculated for 10 repeated measurements
(5 from the left group of barbs and 5 from the right group of barbs
on the same suture) that were made for each of cut angle .theta.
and cut depth D. Barb cut angle .theta. was measured from the surface
of the cut to the outer surface of barbed suture 80. Barb cut depth
D was measured along a perpendicular from the outer surface of barbed
suture 80 toward longitudinal axis A of barbed suture 80. The measurements
enabled cut length L to be calculated using the following formula.
L=D/{Sin (180-.theta.)}
[0143] Also, angle .alpha. of spirality was measured microscopically
on various barbed sutures 80 as follows. When the twisted suture
filament is gripped by the vise during cutting of barbs 81 the
vise leaves a very light mark designated as line M impressed on
the suture filament. Thus, line M will be parallel to the longitudinal
axis of the vise while the twisted suture filament is being held
in the vise. If the vise does not leave a light mark on the suture
filament, then line M can be determined in that it is parallel to
a line connecting the two respective terminus T of the two successive
cut-out depressions CD left in suture body 82 from the escarpment
of two successive barbs 81. After cutting of barbs 81 when barbed
suture 80 is released from the vise and untwisted so that suture
80 lies free, then line M spirals on suture body 82 around barbed
suture 80 forming angle .alpha. of spirality.
[0144] Specifically for measuring spirality angle .alpha., the
Optem Zoom 100 custom microscope was set with ring lighting at 60
and back lighting at coarse 12 and fine 10. Also, imaging analysis
system software was used. Spirality angle .alpha. was then measured
between the outer surface of the barbed suture and line M. The average
was calculated for repeated measurements (5 from the left group
of barbs and 5 from the right group of barbs on the same suture).
[0145] Then, barbed suture 80 was mounted in a twisting device
with one end of suture 80 clamped in a fixed position. The other
end of suture 80 was rotated to insert twist until barbs 81 were
aligned. Next on barbed suture 80 longitudinal cut distance P between
two adjacent barbs 81 was measured microscopically between the two
respective terminus T of the two successive cut-out depressions
CD left in suture body 82 from the escarpment of two successive
barbs 81. The average was calculated for 10 repeated measurements
(5 from the left group of barbs and 5 from the right group of barbs
on the same suture).
[0146] The results are summarized in the following Tables 7A, 7B,
7C, and 7D. TABLE-US-00002 TABLE 7A (size 0 barbed suture) Ratio
of D, L, or P over Suture Diameter Measurement Units Left Right
(0.457 mm) cut angle .theta. degrees 156 .+-. 2 157 .+-. 1 not applicable
cut depth D mm 0.15 .+-. 0.02 0.16 .+-. 0.04 0.35 cut length L mm
0.36 .+-. 0.03 0.40 .+-. 0.10 0.87 cut distance P mm 0.90 .+-. 0.17
0.88 .+-. 0.15 1.92
[0147] TABLE-US-00003 TABLE 7B (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 151 1.642 not applicable
cut depth D mm 0.215 0.027 0.47 cut length L mm 0.446 0.042 0.97
cut distance P mm 0.962 0.073 2.1 spirality angle .alpha. degrees
20.833 1.602 not applicable
[0148] TABLE-US-00004 TABLE 7C (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 154 2.870 not applicable
cut depth D mm 0.205 0.033 0.45 cut length L mm 0.469 0.044 1.03
cut distance P mm 0.975 0.103 2.13 spirality angle .alpha. degrees
19.333 1.506 not applicable
[0149] TABLE-US-00005 TABLE 7D (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 155 2.390 not applicable
cut depth D mm 0.186 0.026 0.41 cut length L mm 0.437 0.039 0.96
cut distance P mm 0.966 0.071 2.11 spirality angle .alpha. degrees
18.833 2.137 not applicable
[0150] Also, some additional measurements of angle .alpha. were
performed on a few additional bi-directional twist cut, multiple
spiral barbed sutures with a diameter of about 0.018 inch (about
0.457 mm, slightly more than the USP requirement for a size 0 synthetic
absorbable suture). The mean average was 16.87 and the standard
deviation was .+-.0.85.
[0151] Additionally, measurements of barb cut angle .theta., barb
length L, barb cut depth D, and cut distance P were performed on
3 additional bi-directional twist cut, multiple spiral barbed sutures
like sutures 80 but having a diameter of about 0.0115 inch (about
0.292 mm, which is slightly more than the USP requirement for a
size 3-0 synthetic absorbable suture), and measurements of spirality
angle .alpha. were performed on 2 of these 3 additional barbed sutures.
Also, measurements of barb cut angle .theta., barb length L, barb
cut depth D, cut distance P, and spirality angle .alpha. were performed
on 3 additional bi-directional twist cut, multiple spiral barbed
sutures like sutures 80 but with a diameter of about 0.015 inch
(about 0.381 mm, which is slightly more than the USP requirement
for a size 2-0 synthetic absorbable suture). The results are summarized
in the following Tables 7E, 7F, 7G, 7H, 7I, and 7J. TABLE-US-00006
TABLE 7E (size 3-0 barbed suture) Ratio of D, L, or Standard P over
Suture Measurement Units Average Deviation Diameter (0.292 mm) cut
angle .theta. degrees 166 1.651 not applicable cut depth D mm 0.107
0.007 0.37 cut length L mm 0.443 0.042 1.52 cut distance P mm 0.956
0.079 3.27 spirality angle .alpha. degrees not not not applicable
tested applicable
[0152] TABLE-US-00007 TABLE 7F (size 3-0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.292 mm) cut angle .theta. degrees 164 2.055 not applicable
cut depth D mm 0.106 0.006 0.36 cut length L mm 0.395 0.042 1.35
cut distance P mm 0.959 0.074 3.28 spirality angle .alpha. degrees
7.329 0.547 not applicable
[0153] TABLE-US-00008 TABLE 7G (size 3-0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.292 mm) cut angle .theta. degrees 165 1.031 not applicable
cut depth D mm 0.104 0.009 0.36 cut length L mm 0.390 0.035 1.34
cut distance P mm 0.975 0.103 3.34 spirality angle .alpha. degrees
7.258 0.636 not applicable
[0154] TABLE-US-00009 TABLE 7H (size 2-0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.381 mm) cut angle .theta. degrees 160.2 1.320 not applicable
cut depth D mm 0.152 0.019 0.40 cut length L mm 0.449 0.057 1.18
cut distance P mm 0.944 0.098 2.48 spirality angle .alpha. degrees
9.40 1.606 not applicable
[0155] TABLE-US-00010 TABLE 7I (size 2-0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.381 mm) cut angle .theta. degrees 161.0 1.707 not applicable
cut depth D mm 0.158 0.014 0.41 cut length L mm 0.489 0.054 1.28
cut distance P mm 0.962 0.054 2.52 spirality angle .alpha. degrees
7.96 1.075 not applicable
[0156] TABLE-US-00011 TABLE 7J (size 2-0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.381 mm) cut angle .theta. degrees 161.0 1.506 not applicable
cut depth D mm 0.154 0.017 0.40 cut length L mm 0.474 0.058 1.24
cut distance P mm 0.973 0.068 2.55 spirality angle .alpha. degrees
6.53 1.755 not applicable
[0157] Additional measurements were performed on several other
twist cut, multiple spiral, barbed sutures manufactured from monofilament
spun from polydioxanone and having a diameter of about 0.018 inch
(about 0.457 mm, which is slightly more than the USP requirement
for a size 0 synthetic absorbable suture) and thus similar to the
above-described tested barbed sutures, except that these other barbed
sutures were cut with a different cutting machine, namely a machine
with one blade that moved longitudinally along the twisted filament
between cutting strokes and that was controlled with a computer
to make the various cuts for the escarpment of the barbs. These
other barbed sutures were also tested for straight pull tensile
strength and for chamois cloth closure strength. (A discussion of
how chamois cloth closure strength is performed can be seen below
in connection with FIGS. 13A and 13B.) The results for these other
barbed sutures are summarized in the following Tables 7K-7Z. TABLE-US-00012
TABLE 7K (size 0 barbed suture) Ratio of D, L, or Standard P over
Suture Measurement Units Average Deviation Diameter (0.457 mm) cut
angle .theta. degrees 152.6 0.718 not applicable cut depth D mm
0.221 0.011 0.48 cut length L mm 0.479 0.022 1.05 cut distance P
mm 0.784 0.015 1.71 spirality angle .alpha. degrees 12.9 0.453 not
applicable
[0158] TABLE-US-00013 TABLE 7L (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 152.4 0.947 not applicable
cut depth D mm 0.216 0.014 0.47 cut length L mm 0.465 0.024 1.02
cut distance P mm 0.774 0.015 1.69 spirality angle .alpha. degrees
13.2 0.349 not applicable
[0159] TABLE-US-00014 TABLE 7M (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 152.3 0.576 not applicable
cut depth D mm 0.227 0.015 0.50 cut length L mm 0.489 0.034 1.07
cut distance P mm 0.796 0.018 1.74 spirality angle .alpha. degrees
13.1 0.193 not applicable
[0160] TABLE-US-00015 TABLE 7N (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 152.8 0.612 not applicable
cut depth D mm 0.207 0.007 0.45 cut length L mm 0.453 0.016 0.99
cut distance P mm 0.798 0.017 1.75 spirality angle .alpha. degrees
13.6 0.560 not applicable
[0161] TABLE-US-00016 TABLE 7O (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 152.9 0.549 not applicable
cut depth D mm 0.188 0.016 0.41 cut length L mm 0.413 0.030 0.90
cut distance P mm 0.787 0.024 1.72 spirality angle .alpha. degrees
13.8 0.270 not applicable
[0162] TABLE-US-00017 TABLE 7P (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 153.1 0.655 not applicable
cut depth D mm 0.204 0.007 0.45 cut length L mm 0.451 0.019 0.99
cut distance P mm 0.792 0.018 1.73 spirality angle .alpha. degrees
13.6 0.410 not applicable
[0163] TABLE-US-00018 TABLE 7Q (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 163.1 0.505 not applicable
cut depth D mm 0.245 0.013 0.54 cut length L mm 0.842 0.045 1.84
cut distance P mm 0.774 0.009 1.69 spirality angle .alpha. degrees
10.8 0.449 not applicable
[0164] TABLE-US-00019 TABLE 7R (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 161.1 1.126 not applicable
cut depth D mm 0.233 0.017 0.51 cut length L mm 0.721 0.035 1.58
cut distance P mm 0.773 0.010 1.69 spirality angle .alpha. degrees
12.6 0.189 not applicable
[0165] TABLE-US-00020 TABLE 7S (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 160.9 0.708 not applicable
cut depth D mm 0.240 0.014 0.52 cut length L mm 0.734 0.037 1.61
cut distance P mm 0.774 0.009 1.69 spirality angle .alpha. degrees
13.6 0.312 not applicable
[0166] TABLE-US-00021 TABLE 7T (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 154.6 1.434 not applicable
cut depth D mm 0.210 0.009 0.46 cut length L mm 0.492 0.026 1.08
cut distance P mm 0.538 0.011 1.18 spirality angle .alpha. degrees
12.3 0.223 not applicable
[0167] TABLE-US-00022 TABLE 7U (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 152.9 0.809 not applicable
cut depth D mm 0.212 0.014 0.46 cut length L mm 0.464 0.026 1.01
cut distance P mm 0.530 0.015 1.16 spirality angle .alpha. degrees
13.7 0.411 not applicable
[0168] TABLE-US-00023 TABLE 7V (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 153.4 0.903 not applicable
cut depth D mm 0.221 0.010 0.48 cut length L mm 0.495 0.023 1.08
cut distance P mm 0.537 0.012 1.17 spirality angle .alpha. degrees
13.9 0.605 not applicable
[0169] TABLE-US-00024 TABLE 7W (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 155.2 0.829 not applicable
cut depth D mm 0.202 0.008 0.44 cut length L mm 0.483 0.017 1.06
cut distance P mm 0.789 0.031 1.73 spirality angle .alpha. degrees
12.6 0.328 not applicable
[0170] TABLE-US-00025 TABLE 7X (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 155.5 0.799 not applicable
cut depth D mm 0.200 0.010 0.44 cut length L mm 0.484 0.027 1.06
cut distance P mm 0.798 0.017 1.75 spirality angle .alpha. degrees
11.8 0.362 not applicable
[0171] TABLE-US-00026 TABLE 7Y (size 0 barbed suture) Ratio of
D, L, or Standard P over Suture Measurement Units Average Deviation
Diameter (0.457 mm) cut angle .theta. degrees 155.4 0.560 not applicable
cut depth D mm 0.196 0.008 0.43 cut length L mm 0.471 0.017 1.03
cut distance P mm 0.799 0.019 1.75 spirality angle .alpha. degrees
11.8 0.496 not applicable
[0172] TABLE-US-00027 TABLE 7Z Chamois Straight Pull Cloth Closure
Strength Strength Barbed Suture (pounds) (pounds to rupture) Sample
1 7.29 11.23 (Tables 7K-7M) Sample 2 8.73 12.14 (Tables 7N-7P) Sample
3 8.5 9.22 (Tables 7Q-7S) Sample 4 5.92 9.27 (Tables 7T-7V) Sample
5 7.69 9.97 (Tables 7W-7Y)
[0173] Although all the above-noted measurements were performed
on bi-directional, twist cut, multiple spiral barbed sutures, the
below-noted desirable ranges for measurements for barb length L,
barb cut depth D, barb cut angle .theta., and/or cut distance P
should be the same for the various other inventive barbed sutures
described here.
[0174] A suitable ratio of cut length L to barbed suture diameter
SD ranges from about 0.2 to about 2 more preferably from about
0.4 to about 1.7 even more preferably from about 0.8 to about 1.5.
However, very suitable barbed sutures may have a ratio of cut length
L to barbed suture diameter SD from about 1 down to about 0.2 whereby
the ratio of the highest possible barb elevation (the elevation
of barb tip 85 above suture body 82) to the suture diameter SD correspondingly
ranges from about 1 down to about 0.2. (The highest possible barb
elevation is the same as the barb length L.) Also, a suitable ratio
of cut depth D to barbed suture diameter SD ranges from about 0.05
to about 0.6 more preferably from about 0.1 to about 0.55 even
more preferably from about 0.2 to about 0.5.
[0175] Regardless, length L may be desirably varied depending on
the intended end use, since larger barbs are more suitable for joining
certain types of tissue such as fat tissue or soft tissue, whereas
smaller barbs are more suitable for joining other types of tissues
such as fibrous tissue. As discussed in more detail below vis-a-vis
FIG. 11 there will also be instances where a barb configuration
that is a combination of large, medium, and/or small barbs disposed
on the same suture will be desirable, for instance, when the barbed
suture is employed in tissue that has differing layer structures.
[0176] Cut angle .theta. formed between the barb and the elongated
suture body desirably would range from about 140 degrees to about
175 degrees, more preferably would range from about 145 degrees
to about 173 degrees. The most preferred cut angle .theta. for all
barbs ranges from about 150.degree. to about 170.degree..
[0177] For instance, for a polydioxanone barbed suture with a diameter
of about 0.018 inch (about 0.457 mm), which is slightly larger that
the USP requirement for a synthetic absorbable suture of size 0
the preferred barb length L would be 0.45 mm; the preferred barb
depth D would be 0.2 mm; and the preferred barb cut angle would
be 153 degrees.
[0178] Longitudinal spacing between any two barbs is generally
effected with the goal of creating as many barbs as possible along
the suture, and is a factor in the ability of the barbed suture
to anchor tissues while maintaining firmness. As barbs are spaced
farther apart, tissue-anchoring capacity decreases. Nevertheless,
if barbs are spaced too close, the integrity of the filament may
be jeopardized, which could lead to a tendency of the barbs to peel
back and also to a decrease in suture tensile strength.
[0179] Generally, a suitable ratio of cut distance P to barbed
suture diameter SD ranges from about 0.1 to about 6 more preferably
from about 0.5 to about 4.5 even more preferably from about 1.0
to about 3.5. Very suitable barbed sutures may have a ratio of cut
distance P to barbed suture diameter SD from about 1.5 down to about
0.2 whereby cut distance P may be as low as about 0.1 particularly
for the overlapping barb embodiment, which is discussed in more
detail below vis-a-vis FIGS. 12A, 12B, 12C, and 12D.
[0180] Additionally, spirality angle .alpha. formed between line
M and the longitudinal direction of the elongated suture body for
a twist cut, multiple spiral barbed suture typically would range
from about 5 degrees to about 25 degrees, more preferably from about
7 degrees to about 21 degrees. The most preferred angle .alpha.
for all barbs on a twist cut, multiple spiral barbed suture is about
110.degree. to about 18.degree..
[0181] Turning now to FIG. 8 shown is suture 90 which is another
embodiment of the present invention. Suture 90 includes elongated
body 92 that is generally circular in cross section. Elongated body
92 terminates in first and second pointed ends 94 96 for penetrating
tissue. It is contemplated that one or both ends 94 96 may comprise
a surgical needle (not shown) for insertion into tissue. Additionally,
suture 90 includes plurality of closely spaced barbs 97 arranged
in a random disposition.
[0182] Suture 90 may be made with the same cutting machine as the
above-discussed sutures, such as the cutting device described in
the above-noted Ser. No. 09/943733 to Genova et al. With combinations
of the above-described methods for making the 180 degree disposition
(sutures 1 10), the 120 degree disposition (sutures 30 40), and/or
the twist cut multiple spiral disposition (sutures 60 70 80),
barbed suture 90 with a very random barb disposition is obtained.
The advantage of the random disposition is that the many barb angles
provide superior anchoring in tissues and thus afford superior wound
holding properties. With the random disposition, the barbed suture
would be inserted into tissue with an insertion device, such as
that shown in the above-noted U.S. Pat. No. 5342376 to Ruff.
[0183] With regard to FIG. 9 shown is a sectional side view of
barbed suture 100 which is another embodiment of the present invention.
Suture 100 includes elongated suture body 102 of generally circular
cross section. Also, suture body 102 has disposed on it a plurality
of closely spaced barbs 107. Each barb 107 has a barb configuration
such that barb underside 108 is serrated or corrugated. One or both
suture ends (not shown) are pointed for penetrating tissue and it
is contemplated that one or both may comprise a surgical needle
(not shown) for insertion into tissue.
[0184] Suture 100 may be made with the same cutting machine as
the above-discussed sutures, such as the cutting device described
in the above-noted Ser. No. 09/943733 to Genova et al. Barb 107
having serrated underside 108 is achieved by vibrating or oscillating
the cutting blades of the cutting device when barbs are being escarped
into the body of a monofilament. It is intended that any of the
barbed sutures of the present invention as described here may have
barbs with a configuration that includes a serrated or corrugated
underside.
[0185] With reference now to FIGS. 10A and 10B, depicted in FIG.
10A is a perspective view and depicted in FIG. 10B is a top view
of barbed suture 110 which is another embodiment of the present
invention. Suture 110 includes elongated suture body 112 of generally
circular cross section. Also, suture body 112 has disposed on it
a plurality of closely spaced barbs 115 having barb tips 117 (one
barb 115 is shown for purposes of brevity). Barb 115 has a configuration
with an arcuate base 119 where barb 115 is attached to suture body
112. One or both suture ends (not shown) are pointed for penetrating
tissue and it is contemplated that one or both may comprise a surgical
needle (not shown) for insertion into tissue.
[0186] FIGS. 10C and 10D are cross-sectional views respectively
along line 10C-10C and line 10D-10D of FIG. 10B. FIGS. 10C and 10D
further clarify that barb 115 becomes narrower going from base 119
toward tip 117.
[0187] Suture 110 may be made with the same cutting machine as
the above-discussed sutures, such as the cutting device described
in the above-noted Ser. No. 09/943733 to Genova et al. To achieve
barb 115 having arcuate base 119 the cutting device is provided
with cutting blades with ends that are correspondingly arcuate with
respect to arcuate base 119.
[0188] It is intended that any of the barbed sutures of the present
invention as described here may have barbs with a configuration
that includes an arcuate base. The arcuate base should enhance tissue
anchoring as compared to a flat, linear base. Regardless, it is
not desired for the base to be circular or oval, which would result
from conical shaped barbs, as that could decrease tissue anchoring.
[0189] Shown in FIG. 11 is a sectional side view of a barbed suture
that is another embodiment of the present invention, and that is
generally designated at 120. Suture 120 includes elongated body
122 that is generally circular in cross section. Elongated body
122 terminates in end 124. End 124 is pointed for penetrating tissue
and it is contemplated that end 124 may comprise a surgical needle
(not shown) for insertion into tissue. (The other end is not shown,
and also may be pointed for penetrating tissue and may comprise
a surgical needle for penetrating tissue.)
[0190] Also, suture 120 includes plurality of closely spaced barbs
125 plurality of closely spaced barbs 127 and plurality of closely
spaced barbs 129. Barbs 125 are relatively small in size with a
relatively short barb length as compared to barbs 127 which are
relatively medium in size with a relatively medium barb length,
as compared to barbs 129 which are relatively large in size with
a relatively long barb length.
[0191] Suture 120 may be made with the same cutting machine as
the above-described sutures were made, such as the cutting device
described in the above-noted Ser. No. 09/943733 to Genova et al.
By altering the amount of blade movement during cutting into a suture
filament, then the barb cut length is made longer or shorter, as
desired, to result in each of the three sets of barbs 125 127
and 129 being of a size different from the others, where the varying
sizes are designed for various surgical applications. The barb size
may also vary in the transverse direction, whereby the barb base
may be short, medium, or long, and regardless, the barb base typically
is less than about 1/4 of the suture diameter.
[0192] For instance, relatively larger barbs are desirable for
joining fat and soft tissues, whereas relatively smaller barbs are
desirable for joining fibrous tissues. Use of a combination of large,
medium, and/or small barbs on the same suture helps to ensure maximum
anchoring properties when barb sizes are customized for each tissue
layer. Only two different sized sets of barbs (not shown) may be
escarped into suture body 122 or additional sets of barbs (not
shown) with four, five, six, or more different sized sets than three
sizes as illustrated for sets of barbs 125 127 and 129 may be
escarped into suture body 122 as desired, in accordance with the
intended end use. Also, although suture 120 is illustrated with
the barbs being unidirectional, it is intended that barbed sutures
with barbs having a configuration of varying sizes in accordance
with the invention also may be bi-directional barbed sutures or
random barbed sutures or any of the other inventive barbed sutures
described here.
[0193] FIG. 12A is a perspective view of another embodiment of
the present invention, showing barbed suture 130 having elongated
body 132 of generally circular cross section. One or both suture
ends (not shown) are pointed for penetrating tissue and it is contemplated
that one or both ends may comprise a surgical needle (not shown)
for insertion into tissue.
[0194] Suture 130 further includes plurality of barbs 135 projecting
from body 132 such that at least two longitudinally adjacent first
and second barbs 135 are disposed on body 132 where first barb 135
overlaps second barb 135 if first and second barbs 135 which is
readily apparent if barbs 135 are laid flat on body 132.
[0195] FIG. 12B is a perspective view of a portion of overlapping
barbs 135 of the overlapping disposition barbed suture 130 of FIG.
12A, and FIG. 12C is a top plan view of FIG. 12B. FIG. 12D is a
cross-sectional view along ling 12D-12D of FIG. 12C. As can be more
clearly seen from FIGS. 12B, 12C, and 12D, during escarpment of
barbs 135 overlapping first barb 135 is escarped into part of topside
TS of overlapped second barb 135 and so on. Part of topside TS
of overlapped second barb 135 becomes part of underside US of overlapping
first barb 135.
[0196] Thus, with the overlapping disposition, the barb cut distance
between first barb 135 and second barb 135 may be shorter than the
barb cut length of overlapped second barb 135 whereas, in general
for barbed sutures, the barb cut distance between two barbs.gtoreq.the
barb cut length. Particularly for the overlapping barb disposition,
very suitable barbed sutures may have a ratio of the barb cut distance
to the barbed suture diameter from about 1.5 down to about 0.2
since the barb cut distance P may be as low as about 0.1. (See discussion
of FIG. 7 for comments vis-a-vis the barb cut length and the barb
cut distance.) This overlapping disposition allows for closely packing
many barbs 135 on body 132 and typically, barbs 135 are thin, as
compared to when the barb cut distance between two barbs.gtoreq.the
barb cut length.
[0197] Also, although suture 130 is illustrated with barbs 135
being unidirectional, it is intended to include that suture 130
in accordance with the invention also may be a bi-directional barbed
suture as described here.
[0198] FIGS. 13A, 13B, 13C, 13D, 14A, 14B, 14C, 14D, 15A, 15B,
15C, 15D, 16A, 16B, 16C, and 16D show various surgical needles,
where a barbed suture is attached to each surgical needle. In order
to facilitate insertion into tissue, the surgical needles may be
coated with a polymer, for instance, as described above vis-a-vis
U.S. Pat. No. 5258013 to Granger et al.
[0199] FIG. 13A shows surgical needle N1 that is a straight elongated
needle in the longitudinal direction and that is generally circular
in cross section. Surgical needle N1 has pointed tip T1 for insertion
into tissue and also has hole H1. Surgical needle N1 is illustrated
as attached, such as by swaging, to barbed suture S1. Barbed suture
S1 is a barbed suture including, but not limited to, any of the
above-described barbed sutures. Additionally, surgical needle N1
has diameter D1 in the transverse direction, which is illustrated
as a relatively thin diameter, such as about 0.02 inch (about 0.51
mm). As discussed above vis-a-vis swaging, surgical needle N1 after
having suture S1 inserted into hole H1 may be crimped by standard
procedures about hole H1 to hold suture S1 in place for suturing
tissue.
[0200] FIG. 13B shows surgical needle N2 that is a straight elongated
needle in the longitudinal direction and that is generally circular
in cross section. Surgical needle N2 has pointed tip T2 for insertion
into tissue and also has hole H2. Surgical needle N2 is illustrated
as attached, such as by swaging, to barbed suture S2. Barbed suture
S2 is a barbed suture including, but not limited to, any of the
above-described barbed sutures. Additionally, surgical needle N2
has diameter D2 in the transverse direction, which is illustrated
as a suitably thin diameter, such as about 0.032 inch (about 0.81
mm), but not as thin as diameter D1 of surgical needle N1. As discussed
above vis-a-vis swaging, surgical needle N2 after having suture
S2 inserted into hole H2 may be crimped by standard procedures
about hole H2 to hold suture S2 in place for use in suturing tissue.
[0201] FIG. 13C shows surgical needle N3 that is a curved elongated
needle in the longitudinal direction and that is generally circular
in cross section. Surgical needle N3 has pointed tip T3 for insertion
into tissue and also has hole H3. Surgical needle N3 is illustrated
as attached, such as by swaging, to barbed suture S3. Barbed suture
S3 is a barbed suture including, but not limited to, any of the
above-described barbed sutures. Additionally, surgical needle N3
has diameter D3 in the transverse direction, which is illustrated
as a relatively thin diameter, such as about 0.02 inch (about 0.51
mm). As discussed above vis-a-vis swaging, surgical needle N3 after
having suture S3 inserted into hole H3 may be crimped by standard
procedures about hole H3 to hold suture S3 in place for use in suturing
tissue.
[0202] FIG. 13D shows surgical needle N4 that is a curved elongated
needle in the longitudinal direction and that is generally circular
in cross section. Surgical needle N4 has pointed tip T4 for insertion
into tissue and also has hole H4. Surgical needle N4 is illustrated
as attached, such as by swaging, t |