Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
In many surgical procedures, surgeons use a
technique which employs a non-needled suture and an eyed
needle. The needle is threaded by the nurse and the surgeon
~; takes one pass through the tissue using a needleholder. He
slips the needle of~ the suture, returns the needle to the
nurse, and is ready for another threaded needle from the
nurse. An assistant follows behind and ties the suture.
,, ,
Sureeons find that this technique is more simple
than using a needled item and cutting the suture with a
scissors a~ter each pass. However, the time required for
threading results in a significant waste of expensive opera-
ting room time.
The security of attachment of eyeless needles to
~ ab~orbable surgical sutures or to nonabsorbable surgical
`~ sutures is prescribed in the U.S. Pharmacopoeia, Vol. XVIII
:, .
at Page 944 (also see U.S. Pharmacopoeia, Vol. XVII, Page 919).
It has been the practice of suture manufacturers in the
United States and abroad to securely attach the suture to
the needle by swaging or with an adhesive so that the minimum
; pull-out standard recited in the U.S. Pharmacopoeia is met
or exceeded. The conversion of the U.S. Pharmacopoeia mini-
mum standard on needle attachment ~rom kilograms to ounces
is summarized in the following table.
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TABLE I
MINIMUM LIMITS ON NEEDLE ATTACHMENT
_
_ Averaqe
size KiloqramsOunces
8/0 0.068 2.39
7/0 0.091 3.20
6/O 0.168 5.92
5/0 0.226 7.97
4/0 0.453 15.97
3/o 0.679 23.63
2/0 1.1 38.80
1/0 1.5 52.89
1 1.8 63.48
2 and larger 1.8 63.48
It will be noted from the abovetable that separation
of the suture from the needle is relatively easyif the suture
is size 5/0 or smaller since the average force requir~d is less
than ~ ounces. On the other hand, the minimal average force
required to separate a size 4/0 suture (diameter 7.0 mils to
9.5 mils) from the needle is about 16 ounces and because needles
are swaged to make quite certain that the minimum U. S. Pharma-
copoeia standards are met, many individual samples require
; forces in excess of 2 pounds to detach the needle from the suture.
There is a need for a needle-suture combination that
has the convenience of the needle being preattached to the
suture and yet permits separation of the needle from the suture
without the necessity of cutting with a scissors.
One approach to this problem is described in Canadian
Patent 1,001,516 issued December 14, 1976 to the assignee of
the present application. This approach involves manufacturing
the needle with an open channel at the blunt end thereof sized
to receive a suture. The suture is bonded to the channel with
an adhesive that prevents "pull-out" of the suture as it
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passes through tissue. After suturing, the surgeon may
easily remove the needle from the suture by turning the
needle so that the channel is at an angle of about 90 to
the direction of the suture and peeling the suture out of
the channel.
This approach has one disadvantage in that many
surgeons prefer a closed channel over an open channel needle
because of the uniform cross-section at the end of the
needle and the smooth transition between the needle and the
attached suture.
It is an ob~ect of the present invention, therefore,
to make available to the surgeon a needle-suture combination
useful in suturing, and characterized by a needle-suture
attachment that will permit facile removal of the needle
from the suture without cutting the suture with a scissors.
Another object of this invention is to provide the
surgeon with a needle-suture combination that will reduce
the time that the surgical patient must spend in the
operating room.
Yet another ob~ect of the invention is to provide
the surgeon with a needle-suture combination that will permit
separation of the needle from the suture after suturing by
a slight pull upon the needle.
Summary of The Invention
Needle-suture combinations manufactured in
accordance wlth the present invention are char~cterizcd by
a suture pull-out value substantially lower than the minimum
average force specified in the U.S. Pharmacopoeia. The
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process of the present inventlon permits better control of
the end product in that the force required to separate a
suture of a particular size from its attached needle is
uniform. Thus, in any batch of needled sutures manufactured
during a single production run, the variation of the pull-
out value from the mean is reduced.
It is an advantage of the product o~ the present
invention, therefore, that the surgeon may readily remove `~
the needle from the suture by exerting a force less than
that specified in Table I and thereby save the time previously
required to cut the suture. The actual force required to
remove the needle from the suture will vary with the suture
size, but can be controlled within the following limits by
the method to be described.
TABLE II
Suture Size Pull-Out Range in Ounces
8/o - 1. _ 2.
7/0 1. - 3.
6/o 2. - 5.
5/ 3. - 7.
4/0 3. - 15.
3/0 3. - 23-
2/0 3. - 26.
1/0 10. - 26.
1 10~ - 26.
2 and larger 10. - 26.
It will be noted from the above table that the
"pull-out" range is lower than that specified in the
U.S. Pharma_o~oeia and in no instance exceeds about
3o 26 ounces.
The suture utilized in the present in~ention may
be any known braided or monofilament suture materials, either
absorbable, i.e., catgut, extruded collagen~ a braided
polyhydroxyacetic ester, a synthetic copolymer of L(-) lactide
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and glycolide; or non-absorbable, i.e., silk, nylon,
polypropylene, cotton, linen, or polyester.
m e needled sutures of the present invention are
manufactured b~ conventional procedures. One end of a
suture is inserted into a drilled needle, a channel needle
or a preclosed channel needle and the needle is swaged to
secure the suture. It has long been known that by proper
control of the diameter of that end of the suture which is
placed in the needle, the diameter of the needle hole and
the swaging processJ needled sutures can be manufactured
that satisfy the minimum limits on needle attachment as set
forth in the U.S. Pharmacopoeia.
It is also known that in swaging, excess force is
to be avoided as over-swaging will weaken the suture strand
and result in the sutUre breaking at the needle. In accor-
dance with the present invention, the needled sutures are
swaged so that the force required to pull the suture out
of the needle exceeds the minimum limits on needle attach-
ment set forth in Table 1, but is less than the actual
tensile strength of the suture used.
Preferably, the needles are swaged so that the
suture may be pulled out of the needle by a force in the
range of l-to 6 pounds for size 4/0 suture and larger. If
the suture is smaller than size 4/0, it is preferred that the
needle be swaged so that the suture may be pulled out of the
needle without breaking by a force in the range of 3 to
15 ounces as lndicated in the following table.
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TABL~ III
Force in Ounces Required
. . .. t.o Move.Sut.ure Relative
Suture Size to the Needle Barrel
.
8/o 3.
7/0 4.
6/o 8.
5/o 15.
The pull-out characteristicæ that distinguish
the product of the present invention are obtained by pre-
stressing the suture, i.e., tension is applled to the suture
after the swaging step partially pulling the suture out of
the needle. As the suture is pulled from the needle, the
force requlred to move the suture relative to the swaged
sectlon decreases. When the force required to move the end
of the suture relative to the needle barrel drops to the
desired pull-out value, the tension is released. ~-
It has been noted that if the bond between the
; needle and its attached suture is within the range set forth
:~ 20 in Table II, the suture will not separate from the needle
. ~ .
as the surgeon.passes the needle through tissue. Yet, the
needle can-easily be removed from the suture at any time b~
simply pulling.on the needle with a force of from 1 to about
26 ounces depending upon the suture ~lze. Needle-suture
combinations having the pull-out values summarized in Table II
ma~ be manufactured by applying sufficient tension to the
suture to move it relative to the needle barrel, and then re-
leasing the tension when the force drops to within the
following range for that size of suture.
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Suture Size Oùnces
8/0 1. - 2.
7/0 1. - 3.
6/0 2, - 5.
5/0 3. - 7.
4/0 5. - 15.
3/0 5. - 23.
2/0 5. - 26.
1/0 10. - 26,
1 10. - 26.
2 and larger 10. - 26.
According to a broad aspect of the present invention
there is provided a method of manufacturing a swaged needle-
sutu~e combination having a desired pull-out value. The
~; method comprises the steps of securing a suture within an
axial opening in the blunt end of a needle barrel by swaging.
Sufficient tension is applied to the suture to move it relative
to the needle barrel. The tension is released when the force
drops to the desired pull-out value.
.
20 ~ According to a further broad aspect of the present
invention there is provided a swaged needle-suture combination
comprising a needle having an axial opening in the blunt end
and a suture, one end of which is received within the opening and
secured therein by swaging. The suture is displaced a con-
trolled distance from the inner end of the opening whereby the
suture may be pulled out of the neadle by a force that is within
the following range for that size of suture
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Suture Size Ounces
. .
8/0 1. - 2.
7/0 1. - 3.
6/0 2. - 5,
5/0 3 _ 7
4/0 3. - 15.
3/0 3. - 23.
2/0 3. - 26.
1/0 10. - 26.
1 10. - 26,
2 and larger10. - 26.
The invention will appear more clearly from the
following detailed description when taken in connection with the
accompanying drawings which show by way of example preferred
embodiments of the inventive idea.
Brief Description of the Drawinqs
Figure 1 is an enlarged perspective view of a swaged
and stressed needle-suture combination,
Figure 2 is an enlarged perspective view of the
needle-suture combination of Figure 1 and illustrates removal
of the needle from the suture'
Figure 3 is an enlarged sectional view of a needle-
suture combination,
Figure 4 is an enlarged sectional view of the needle-
. suture combination of Figure 3 showing displacement of the
suture from the needle,
Figure 5 is a diagram of apparatus useful in manu-
facturing the needled sutures of the present invention,
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Figure 6 is a graph of`the displacement of a suture
from the drilled hole as a function of the stress applied to
the suture'
Figure 7 is a graph of the displacement of a suture
from the drilled hole as a function of the stress applied to
the suture,
,~
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Flgure 8 is a graphic representation of the pull-
out values determined on eleven prestressed needle-suture
combinations,
Figure 9 is a graph of the displacement of a
suture from the needle hole as a function of the stress
applied,
Figure 10 is a graph of the displacement of a
suture from the needle hole as a function of the stress
applied;
Figure 11 ls a graphic representation of the
7 pull-out values determined on ten needle-suture combinations.
- ;
Description of the Preferred Embodiments
In accordance with the present invention, needled
sutures are manufactured in the conventional manner and
prestressed to reduce the force required to separate the
needle from the suture to a predetermined value. The
resulting controlled release suture is then packaged and
,7~ sterilized.
Prestressing may be accomplished by the apparatus ;~
- illustrated in Fig. ~ which is designed to apply a stress
~20 to a needle ll and the attached suture 12 sufficient to
:` partially withdraw the suture from the needle. It includes
~ in part an arm 13 fitted with a gate 14 sized to retain
. .,
stationary the needle while permitting movement of the suture
-~ relative thereto. The arm is pivoted for movement around
~,
' 25 the pivot pin 15. A clamp 16 fitted with movable ~aws 17
- and 17' is aligned with the gate and grips the suture,
. .
Movement of the clamp in the direction of the arrow applies
._ 9 _
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stress to the sUture c~using it to move relative to the
needle barrel 30 thereby displaclng the end 18 of the
suture from the bottom 20 of the needle hole b~ a distance
l9 (see Figs. 3 and 4).
The stress applied to the suture by the clamp is
monitored by a force transducer 21 which acts with the clamp
to stop the movement thereof when the applied stress drops
to a predetermined value.
Figure 6 illustrates the relationship between stress,
strain, and the actual displacement of four size 0 black
braided silk sutures as tension is applied to pull the sutures
completely out of the needle. The sutures are swaged to a
39 mil drilled needle. The diameter of the drill hole is
l9 mils and the depth of the drill hole (the length of the
suture within the needle barrel) is 70 mils.
Figure 7 illustrates the relationship between stress,
strain, and-the actual displacement of four ~ize 0 black
braided silk sùtures as tension is applied to pull the
sutures out of the needle. The sutures are swaged to a 39
mil drllIed needle. The diameter o~ the drill hole is l9
mile and the depth of the drill hole (the length of the
suture within~the needle barrel) is 70 mils. In thls in-
stance, the sutures are not pulled completely out of the
needle; when the tension drops to l pound, the~movement of
the clamp is stopped.
Figure 9 illustrates the relationship between
stress, strain, and the actual displacement of a size 0
polye8ter suture ~rom a channel needle. The needle is made
of 39 mil wire and has a channel length (prior to closure)
of 178 mils.
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As tension is applled to the suture by the clamp,
the suture is elongated (about 0.02 inches) until the stress
exceeds 6 pounds. At that point, the suture moves relative
to the needle and the stress drops as the suture is with-
drawn. Movement of the clamp is stopped when the stressreaches 1 pound at which point the displacement of the
suture ~rom the end of the needle channel is about 0.09
inches (about 50~ displacement).
Figure 10 deplcts the relationship of stress,
strain, and suture displacement when force is applied to a
size 0 polypropylene suture swaged to a channel needle. me
needle is made of 39 mil wire and has a channel length (prior
to closure) 188 mils. In this instance, as the stress is
increased to about 4 pounds, the suture is stretched about
0.02 inches. Increasing the stress above 4 pounds results in
vement of the suture relative to the needle channel.
Stress is removed when the force applied drops to 1 pound at
which point the suture has been displaced ~rom the channel
~; needle a d1stance of about o.o8 inches (about 42% dis-
placement).
e following examples will serve to further
illustrate the invention.
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EXAMPLE
Size O black braided silk æuture strands are
swaged to drilled needles manu~actured of 39 mil wire and
having a drilled hole in the blunt end 19 mils in diameter
and 70 mils deep. The suture ends are inserted into the
needles until they are in contact with the bottom of the
drilled hole as shown in Figure 3. The needles are then
swaged so that the force required to pull out the suture is
within the range of about from 2 to 5 pounds.
The swaged needle-suture combinations are pre-
stressed in a Table Model INSTRON Tensile Tester (ModelTT-DL) using a Type CT Tension Cell (full-scale range 100
pounds), and the machine is set so that full-scale deflection
is obtained at 20 pounds. Two line contact jaws are used
to secure the needled sutures in the INSTRON machine. The
upper jaw grips the needle and the lower jaw grips the
suture about 0.25 inches below the needle. Both jaws are
closed under 20 p.s.i. air pressure. The INSTRON machine
is operated at a cross-head speed of 0.1 inches per minute
and a chart speed of 5 inches per minute until the t~n~ion
drops to one pound.
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Ten prestressed needle-suture comblnations ran-
domly selected from this production batch are replaced
in the INSTRON machine and stressed to pull the suture out
o~ the needle. The pull-out value for each o~ the ten
sutures is'recorded below:
14 ounces 14-1/2 ounces
13 ounces 13-1/2 ounces
14 ounces 11 ounces
14 ,ounces 15 ounces
16-1/2 ounces 15 ounces.
The narrow distribution of pull-out values is graphically
illustrated in Figure 11.
EXAMPLE 2
Size O monofilament polypropylene suture strands
are swaged to drilled needles manufactured o~ 3g mil wire
~15 and having a drilled hole in the blunt end 19 mils in dia-
meter and 70 mils deep. m e ends are inserted into the
needIes until they are in contact with the bottom of the
drilled hole,as shown in Figure 3. The needles are swaged
so that the,force required to pull the suture out o~ the
needle is within the range of from about 3 to 5 pounds.
The swaged needle-suture combinations are pre-
stressed in a Table Model INSTRON Tensile Tester (Model
TT-DL) using a Type CT Tension Cell (full-scale range
100 pounds), and the machine is set-so that ~ull-scale
'I 2'5 de~lection is obtained at 20 pounds. Two line contact jaws
J ~ are used to secure the needled sutures in the INSTRON
i, machine. The upper jaw grips the needle and the lower jaw
~, grips the suture about 0.25 inches below the needle. Both
' jaws are closed under 20 p.s.1. air pressure. The INSTRON
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machine is operated at a cross-head speed of 0.1 lnches per
minute and a chart speed of 5 inches per minute until the
tension drops to one pound.
Eleven prestressed needle-suture combinations
randoml~ selected from this production batch are replaced
in the INSTRON machine and stressed to pull the suture out
of the needle. The pull-out value for each of the eleven
sutures is recorded below:
17-1/2 ounces 16 ounces
17-1/2 ounces 16 ounces
17 ounces 17 ounces
17 ounces 17 ounces
16-l/2 ounces 1~ ounces
1~ ounces.
The narrow distribution of the pull-out values is graphically
illustrated in Figure 8.
EXAMPLE 3
A size 2 black braided silk suture strand is
swaged to a channel needle mRnufactured of 39 mil wire.
The length of the channel (the length of the suture within
the needle barrel) is 7/32 inches. me needles are swaged
so that the force required to pull out the suture is about
5 pounds.
The swaged needle-suture combination is pre-
stressed in a Table Model INSTRON Tensile Tester as described
in Example l above, until the tension required to pull the
suture from the needle drops to 21 ounces.
Ten~prestressed needle-suture combinations ràndomly
selected from this production batch are replaced in the
INSTRON machine and stressed to pull the suture out o~ the
needle. The pull-out value for each of the ten sutures is
; recorded below:
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14 ounces 17 ounces
15 ounces 18 ounces
22 ounces 21 ounces
14 ounces 20 ounces
16-1/2 ounces 26 ounces.
EXAMPLE 4
A size 1 black braided silk suture strand is
swaged to a drilled needle manufactured of 32 mil wire and
having a drilled hole in the blunt end 22 mils in diameter
and 70 mils deep. The end of the suture is inserted into
the needle until it is in contact with the bottom of the
drilled hole as shown in Figure 3. The needle is then
swaged so that the force required to pull the suture out of
the needle is~withln the range of about from 3 to 6 pounds.
The swaged needle-suture combination is then
prestressed in a Table Model INSTRON Tensile Tester (Model
TT-DL) using a Type CT Tension Cell (full-scale range 100
pounds), and the machine is set so that full-scale deflection
1s obtained at 20 pounds. Two line contact jaws are used
to secure the needled suture in the INSTRON machine. The
20 - upper ~aw grips the needle and the lower jaw grips the
.
suture about 0.25 inches below the needle. Both jaws are
closed under 20 p.s.i. air pressure. me INSTRON machine
is operated at a cross-head speed oi 0.1 inches per minute
and a chart speed of 5 inches per minute until the tensicn
~25 drops to 20 ounces.
Ten prestressed needle-suture combinations ran-
domly selected from this production batch are replaced in
the INSTRON machine and stressed to pull the suture out of
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the needle. The pull-out value ~or each of the ten
sutures is recorded below:
15 ounces 20 ounces
16 ounce~ 24 ounces
15 ounces 21 ounces
18 ounces 19 ounces
16-1/2 ounces 22 ounces.
ExAMpLE 5
Size-3/0 black braidëd silk suture strands are
swaged to channel needles manufactured of 22 mil wire and
having a channel in the blunt end 5/32 inch in length
(5/32 inch suture engagement~. The needles are swaged to
close the channel so that the force required to pull out
the suture is within the ra~ge of about from 1 to 2 pounds.
m e swaged needle-suture combinations are
prestressed in a Table Model INSTRON Tensile Tester as
descrlbed above until the tension drops to 11 ounces.
Ten prestressed needle-suture combinations randomly
selected from this production batch are replaced in the
INSTRON machine and stressed to pull the suture out of the
needle. The pull-out value for each of the ten sutures is
recorded below:
11 ounces 12 ounces
8 ounces 8 ounces
7 ounces ~ ounces
11 ounces 8 ounces
13 ounces 7 ounces.
EXAMPLE 6
Slze 4/0 black bralded silk suture strands are
swaged to channel needles manufactured of 17 mil wire (suture
engagement 9/64 inches). The needles are swaged so that the
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force required to pull out the suture ls about 1 pound.
The swaged needle-suture combinatlons are pre-
stressed ln a Table Model INSTRON Tenslle Tester as
described ln Example 1 above untll the tenslon drops to
8 ounceæ.
Ten prestressed needle-suture combinations ran-
domly selected from this production batch are replaced ln
the INSTRON machine and stressed to pull the suture out of
the needle. The pull-out value for each of the ten sutures
is recorded belcw:
6-1/2 ounces 6 ounces
ounces 7-1/2 ounces
8 ounces 9 ounces
6 ~unces 7 ounces
~15 6 1~2 ounces 6 ounces.
EXAMPLE 7
Size 5/0 black braided silk suture strands are
swaged to channel needles manufactured of 14 mil wire
(channel eng;agement 7/64 inch). The needles are swaged
~; 20~ so that~the rOrce required to pull out the suture is within
the range oi 7 to 15 ounces.
e swaged needle-suture combinations are pre-
stressed in a TaOle Model INSTRON Tensile Te~ter (Model TT-
DL) using a Type G-01-3 Tension Cell (full-scale range 50
25~ pounds), and the machlne is set so that full-scale deflection
is obtained at 5 pounds. Two line contact ~aws are used to
sècure the~needled sutures in the INSTRON machlne. The upper
Jaw grips the needle and the lower ~aw grips the suture about
0.25 inches below the needle. Both ~aws are closed under
~; 30 20 p.s.i. air pressure. m e INSTRON machlne ls operated at a
cross-head speed of 0.1 inches per mlnute and a chart speed of
5 inche~ per minute until the tension drops to 4 ounces.
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Ten prestressed needle-suture combinations ran-
domly selected from this production batch are replaced in
the INSTRON machine and stressed to pull the suture out of
the needle. The pull-out value ~or each of the ten sutures
is recorded below:
3.2 ounces 3.~2 ounces
3.76 ounces 4.61 ounces
4.71 ounces 3.10 ounces
3.70 ounces 3.25 ounces
4.12 ounces 3.15 ounces.
EXAMP~E 8
Size 6/o polyester suture strands are swaged to
preclosed channel needles manufactured of 12 mil wire and
having a suture engagement of 7/64 inches. The needles are
swaged so that the force required to pull out the suture is
within the range of 5 to 8 ounces.
The swaged needle-suture combinations are prestressed
in a Table Model INSTRON Tensile Tester (Model TT-DL) using
a Type G-01-3 Tension Cell (full-scale range 50 pounds), and
the machine is set so that full-scale deflection is obtained
at 5 pounds. Two line contact jaws are used to secure the
needled sutures in the INSTRON machine. The upper jaw grips
the neèdle and the lower jaw grips the suture about 0.25 inches
below the needle. Both jaws are closed under 20 p.s.i. air
pressure. The INSTRON machine is operated at a cross-head
speed of o.i inches per minute and a chart speed of 5 inches
per minute until the tension drops to 3 ounces.
Ten prestressed needle-suture combinations random-
ly selected from this productlon batch are replaced in the
30 INSTRON machine and stressed to pull the suture out of the
needle. The pull-out value for each of the ten sutures
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is recorded below:
3.05 ounces 3.10 ounces
2.51 ounces 2.75 ounces
2.35 ounces 2.70 ounces
2.56 ounces 3.58 ounces
2.78 ounces 2.93 ounces.
EXAMPLE 9
Size 7/0 white virgin silk suture strands are
swaged to preclosed channel needles manu~actured of 8 mil
wire tchannel engagement 50 m~ls). The needles are swaged so
that the force required to pull out the suture is within the
range of 3 to 4 ounces.
The swaged needle-suture combinations are pre-
stressed in a Table Model INSTRON Tensile Tester (Model
TT-DL) using a B Tension Cell and the associated upper jaw
(red). The instrument is calibrated with a 100 gram weight
on the B cell clamp to full-scale deflection on the X-l
scale. Two line contact jaws are used to secure the needled
sutures in the INSTRON machine. The upper jaw grips the
needle and the lower Jaw grips the sùture about 0.25 inches
below the needle. Both ~aws are closed under 20 p~s.i. air
preæsure. The INSTRON machine is operated at a cross-head
speed of 0.1 inches per minute and a chart speed of 5 inches
per minute until the tension drops to 1.8 ounces.
Ten prestressed needle-suture comblnations randoml~
; selected from this production batch are replaced in the
INSTRON machine and stressed to pull the suture out o~ the
needle. The pu}l-out value for each of the ten sutures is
recorded below:
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1.73 ounces 1.53 ounces
1.46 ounces 1.60 ounces
1.28 ounces 1.98 ounces
1.40-ounces 1.39 ounces
1.82 ounces 1.77 ounces.
EXAMPLE 10
Size 8/o white virgin silk suture strands are
swaged to preclosed channel needles manufactured of 8 mil
wire (channel engagement 50 mils). The needles are swaged so
that the force required to pull out the suture is within the
range of 2 to 3 ounces.
The swaged needle-suture combinations are prestressed
in a Table Model INSTRON Tensile Tester (Model TT-DL) using
a Type B Tension Cell and the associated upper jaw (red). The
instrument is calibrated with a 100 gram weight on the B cell
clamp to ~ull-scale deflection on the X-l scale. Two line
contact jaws are used to secure the needled sutures in the
INSTRON machine. m e upper jaw grips the needle and the lower
jaw grips the suture about 0.25 inches below the needle.
Both ~aws are closed under 20 p.s.i.air pressure. The INSTRON
machine is operated at a cross-head speed of 0.1 inches per
minute and a chart speed of 5 inches per minute until the
tension drops to 1.3 ounces.
Ten prestressed needle-suture combinations randoml~
selected from this production batch are replaced in the INSTRON
machine and stressed to pull the suture out of the needle.
The pull-out value for each of the ten sutures is recorded
; below:
1.08 ounces 1.45 ounces
1.04 ounces 1.18 ounces
1.24 ounces 1.11 ounces
1.27 ounces 1.29 ounces
1.13 ounces 1.31 ounces.
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EX~MPLE 11
Size 2/0 black braided silk suture strands are
swaged to channel needles manufactured of 26 mil wire
(channel engagement 11/64 inch). The suture ends are
inserted into the needles until they are in contact with the
bottom of the drilled hole as shown in Figure 3. The needles
are then swaged so that the force required to pUll out the
suture is within the range of about from 2 to 4 pounds.
The swaged needle-suture combinatlons are
prestressed in a Table Model INSTRON Tensile Tester (Model
TT-DL) using a T~pe CT Tension Cell ~full-scale range
100 pounds), and the machine is set so that full-scale
deflection is-obtained at 20 pounds. Two line contact ~aw~
are used to secure the needled sutures in the INSTRON
machine. m e upper jaw grips the needle and the lower jaw
grips the suture about 0.25 inches below the needle. Both
jaws are closed under 20 p.s.i. air pressure. The INSTRON
machine is operated at a cross-head speed of 0.1 inches per
minute and a chart speed of 5 inches per minute until the
stress drops to 14 ounces.
Ten prestressed needle-suture combinations ran-
domly selected from this production batch are replaced in
the INSTRON machine and stressed to pull the suture out of
the needle. The pull-out value for each of the ten sutures
is recorded below:
~ 258 ounces 11 ounces
; 16 ounces 13 ounces
9 ounces 13 ounces
10-1/2 ounces 12 ounces
11 ounces 14 ounces.
'
ETH-382
~04Z301
The needle-suture combinatlons of the present
invention may be used by the surgeon employing conventional
suturing technique as illustrated in Figure 1. After the
sUture has been placed, the needle may be separated by a
wrist motion snapping the needle o~f the end of the suture
as best illustrated in Figure 2. The force required to pull
the needle ~rom the end of the suture is related to the
suture size and is in the range of from about 1 ounce to
about 26 ounces.
-2~-
