U.S. patent number 3,875,946 [Application Number 05/446,174] was granted by the patent office on 1975-04-08 for controlled release suture.
This patent grant is currently assigned to Ethicon, Inc.. Invention is credited to Robert Barclay Duncan.
United States Patent |
3,875,946 |
Duncan |
April 8, 1975 |
Controlled release suture
Abstract
A needle-suture combination having a suture pull-out value in
the range of 1 to 26 ounces is manufactured by applying sufficient
tension to the suture to move it relative to the needle barrel and
releasing the tension when the force drops to within the following
range for that size of suture: Suture Size Ounces
______________________________________ 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.
______________________________________
Inventors: |
Duncan; Robert Barclay
(Somerville, NJ) |
Assignee: |
Ethicon, Inc. (Somerville,
NJ)
|
Family
ID: |
23771586 |
Appl.
No.: |
05/446,174 |
Filed: |
February 27, 1974 |
Current U.S.
Class: |
606/227; 163/5;
163/1 |
Current CPC
Class: |
A61B
17/06004 (20130101) |
Current International
Class: |
A61B
17/06 (20060101); A61b 017/06 () |
Field of
Search: |
;128/335.5,339,334R
;163/5,1 ;223/102 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Eberhardt; Wayne R.
Claims
What is claimed is:
1. In a method of manufacturing a swaged needle-suture combination
comprising a needle having pointed and blunt ends, said needle
having an opening in the blunt end thereof and a suture, one end of
which is received within said opening, the improvement comprising
pre-stressing the suture with respect to said needle by applying
sufficient tension to the suture to move it relative to said
needle; and releasing the tension when the force drops to a value
within the following range for that size of suture
2. A swaged needle-suture combination comprising a needle having
pointed and blunt ends, said needle having an opening in the blunt
end thereof and a suture, one end of which is received within said
opening said suture being pre-stressed with respect to said needle
so that the suture is displaced from the inner end of said opening
whereby the suture may be pulled out of the needle by a force that
is within the following range for that size of suture
3. The needle-suture combination of claim 2, wherein the suture is
displaced from the inner end of the opening a distance of about
0.08 inches.
4. The needle-suture combination of claim 2, wherein the suture is
displaced from the inner end of the opening a distance of about 42
to 50 per cent of the length of said opening.
5. The needle-suture combination of claim 2, wherein the needle is
a drilled needle.
6. The needle-suture combination of claim 2, wherein the needle is
a channel needle.
7. The needle-suture combination of claim 2, wherein the suture is
a covered silk suture.
8. The needle-suture combination of claim 2, wherein the suture is
a braided polyester suture.
9. The needle-suture combination of claim 8, wherein said polyester
is polyhydroxyacetic ester.
10. The needle-suture combination of claim 8, wherein said
polyester is a copolymer of glycolide and L(-) lactide.
11. The needle-suture combination of claim 2, wherein the suture is
a braided nylon suture.
12. The needle-suture combination of claim 2, wherein the suture is
a braided suture.
13. The needle-suture combination of claim 2, wherein the suture is
a braided silk suture.
14. The needle-suture combination of claim 2, wherein the suture is
a monofilament.
15. The needle-suture combination of claim 2, wherein the needle is
a curved needle.
16. The needle-suture combination of claim 2, wherein the needle is
a straight needle.
17. The needle-suture combination of claim 2, wherein the needle is
a cutting edge needle.
18. The needle-suture combination of claim 2, wherein the needle is
a taper point needle.
Description
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 off 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.
Surgeons find that this technique is more simple than using a
needled item and cutting the suture with a scissors after each
pass. However, the time required for threading results in a
significant waste of expensive operating room time.
The security of attachment of eyeless needles to absorbable
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 minimum standard on needle attachment from kilograms
to ounces is summarized in the following table.
TABLE I ______________________________________ MINIMUM LIMITS ON
NEEDLE ATTACHMENT ______________________________________ Average
______________________________________ Size Kilograms Ounces
______________________________________ 8/0 0.068 2.39 7/0 0.091
3.20 6/0 0.168 5.92 5/0 0.226 7.97 4/0 0.453 15.97 3/0 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 above table that separation of the suture
from the needle is relatively easy if the suture is size 5/0 or
smaller since the average force required is less than 8 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. Pharmacopoeia 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 copending application
Ser. No. 252,176, filed May 11, 1972, now U.S. Pat. No. 3,799,169.
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 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.degree. 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 object 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 object 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 with the
present invention are characterized by a suture pull-out value
substantially lower than the minimum average force specified in the
U.S. Pharmacopoeia. The process of the present invention 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 of 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 ______________________________________ 8/0
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 larger 10. - 26.
10. - 26. ______________________________________
It will be noted from the above table that the "pull-out" range is
lower than that specified in the U.S. Pharmacopoeia and in no
instance exceeds about 26 ounces.
The suture utilized in the present invention 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 and glycolide; or
non-absorbable, i.e., silk, nylon, polypropylene, cotton, linen, or
polyester.
The needled sutures of the present invention are manufactured by
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 process, 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 accordance 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
attachment set forth in Table I, 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 1 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 indicated in the following table.
TABLE III ______________________________________ Force in Ounces
Required to Move Suture Relative Suture Size to the Needle Barrel
______________________________________ 8/0 3. 7/0 4. 6/0 8. 5/0 15.
______________________________________
The pull-out characteristics that distinguish the product of the
present invention are obtained by prestressing the suture, i.e.,
tension is applied 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 required to move the suture relative to the
swaged section 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 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 by simply pulling on the needle with a force
of from 1 to about 26 ounces depending upon the suture size.
Needle-suture combinations having the pull-out values summarized in
Table II may be manufactured by applying sufficient tension to the
suture to move it relative to the needle barrel, and then releasing
the tension when the force drops to within the following range for
that size of suture.
______________________________________ Suture Size Ounces
______________________________________ 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.
______________________________________
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 DRAWINGS
FIG. 1 is an enlarged perspective view of a swaged and stressed
needle-suture combination;
FIG. 2 is an enlarged perspective view of the needle-suture
combination of FIG. 1 and illustrates removal of the needle from
the suture;
FIG. 3 is an enlarged sectional view of a needle-suture
combination;
FIG. 4 is an enlarged sectional view of the needle-suture
combination of FIG. 3 showing displacement of the suture from the
needle;
FIG. 5 is a diagram of apparatus useful in manufacturing the
needled sutures of the present invention;
FIG. 6 is a graph of the displacement of a suture from the drilled
hole as a function of the stress applied to the suture;
FIG. 7 is a graph of the displacement of a suture from the drilled
hole as a function of the stress applied to the suture;
FIG. 8 is a graphic representation of the pull-out values
determined on eleven prestressed needle-suture combinations;
FIG. 9 is a graph of the displacement of a suture from the needle
hole as a function of the stress applied;
FIG. 10 is a graph of the displacement of a suture from the needle
hole as a function of the stress applied;
FIG. 11 is a graphic representation of the 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 sterilized.
Prestressing may be accomplished by the apparatus illustrated in
FIG. 5, which is designed to apply a stress to a needle 11 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
the pivot pin 15. A clamp 16 fitted with movable jaws 17 and 17' is
aligned with the gate and grips the suture. Movement of the clamp
in the direction of the arrow applies stress to the suture causing
it to move relative to the needle barrel 30 thereby displacing the
end 18 of the suture from the bottom 20 of the needle hole by a
distance 19 (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.
FIG. 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 19 mils and the depth of the drill
hole (the length of the suture within the needle barrel) is 70
mils.
FIG. 7 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 out of the needle. The
sutures are swaged to a 39 mil drilled needle. The diameter of the
drill hole is 19 mils and the depth of the drill hole (the length
of the suture within the needle barrel) is 70 mils. In this
instance, the sutures are not pulled completely out of the needle;
when the tension drops to 1 pound, the movement of the clamp is
stopped.
FIG. 9 illustrates the relationship between stress, strain, and the
actual displacement of a size 0 polyester suture from a channel
needle. The needle is made of 39 mil wire and has a channel length
(prior to closure) of 178 mils.
As tension is applied 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 withdrawn. Movement of the clamp is stopped
when the stress reaches 1 pound at which point the displacement of
the suture from the end of the needle channel is about 0.09 inches
(about 50% displacement).
FIG. 10 depicts the relationship of stress, strain, and suture
displacement when force is applied to a size 0 polypropylene suture
swaged to a channel needle. The 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 movement 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 from the channel needle a
distance of about 0.08 inches (about 42% displacement).
The following examples will serve to further illustrate the
invention.
EXAMPLE 1
Size 0 black braided silk suture strands are swaged to drilled
needles manufactured 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 FIG. 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 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 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 tension drops to one pound.
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:
14 ounces 141/2 ounces 13 ounces 131/2 ounces 14 ounces 11 ounces
14 ounces 15 ounces 161/2 ounces 15 ounces
The narrow distribution of pull-out values is graphically
illustrated in FIG. 11.
EXAMPLE 2
Size 0 monofilament polypropylene suture strands are swaged to
drilled needles manufactured of 39 mil wire and having a drilled
hole in the blunt end 19 mils in diameter and 70 mils deep. The
ends are inserted into the needles until they are in contact with
the bottom of the drilled hole as shown in FIG. 3. The needles are
swaged so that the force required to pull the suture out of the
needle is within the range of from about 3 to 5 pounds.
The swaged needle-suture combinations are 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 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 tension drops to 1 pound.
Eleven 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 11 sutures is recorded below:
171/2 ounces 16 ounces 171/2 ounces 16 ounces 17 ounces 17 ounces
17 ounces 17 ounces 161/2 ounces 17 ounces 18 ounces
The narrow distribution of the pull-out values is graphically
illustrated in FIG. 8.
EXAMPLE 3
A size 2 black braided silk suture strand is swaged to a channel
needle manufactured of 39 mil wire. The length of the channel (the
length of the suture within the needle barrel) is seven
thirty-seconds inches. The needles are swaged so that the force
required to pull out the suture is about 5 pounds.
The swaged needle-suture combination is prestressed in a Table
Model INSTRON Tensile Tester as described in Example 1 above, until
the tension required to pull the suture from the needle drops to 21
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 10 sutures is recorded below:
14 ounces 17 ounces 15 ounces 18 ounces 22 ounces 21 ounces 14
ounces 20 ounces 161/2 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 FIG. 3. The needle is then
swaged so that the force required to pull the suture out of the
needle is within 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 is obtained at 20 pounds. Two line contact
jaws are used to secure the needled suture 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 tension drops to 20 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 10 sutures is recorded below:
15 ounces 20 ounces 16 ounces 24 ounces 15 ounces 21 ounces 18
ounces 19 ounces 161/2 ounces 22 ounces
EXAMPLE 5
Size 3/0 black braided silk suture strands are swaged to channel
needles manufactured of 22 mil wire and having a channel in the
blunt end five thirty-seconds inch in length (five thirty-seconds
inch suture engagement). The needles are swaged to close the
channel so that the force required to pull out the suture is within
the range of about from 1 to 2 pounds.
The swaged needle-suture combinations are prestressed in a Table
Model INSTRON Tensile Tester as described 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 10 sutures is recorded below:
11 ounces 12 ounces 8 ounces 8 ounces 7 ounces 9 ounces 11 ounces 8
ounces 13 ounces 7 ounces
EXAMPLE 6
Size 4/0 black braided silk suture strands are swaged to channel
needles manufactured of 17 mil wire (suture engagement nine
sixty-fourths inches). The needles are swaged so that the force
required to pull out the suture is about 1 pound.
The swaged needle-suture combinations are prestressed in a Table
Model INSTRON Tensile Tester as described in Example 1 above until
the tension drops to 8 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 10 sutures is recorded below:
61/2 ounces 6 ounces 9 ounces 71/2 ounces 8 ounces 9 ounces 6
ounces 7 ounces 61/2 ounces 6 ounces
EXAMPLE 7
Size 5/0 black braided silk suture strands are swaged to channel
needles manufactured of 14 mil wire (channel engagement seven
sixty-fourths inch). The needles are swaged so that the force
required to pull out the suture is within the range of 7 to 15
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 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 tension drops to 4 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 10 sutures is recorded below:
3.2 ounces 3.42 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
EXAMPLE 8
Size 6/0 polyester suture strands are swaged to preclosed channel
needles manufactured of 12 mil wire and having a suture engagement
of seven sixty-fourths 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 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 tension drops to 3 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 10 sutures 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 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 3 to 4 ounces.
The swaged needle-suture combinations are prestressed 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-1 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 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 tension
drops to 1.8 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 10 sutures is recorded below:
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 8/0 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 full-scale
deflection on the X-1 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 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 tension drops to 1.3 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 10 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
EXAMPLE 11
Size 2/0 black braided silk suture strands are swaged to channel
needles manufactured of 26 mil wire (channel engagement eleven
sixty-fourths inch). The suture ends are inserted into the needles
until they are in contact with the bottom of the drilled hole as
shown in FIG. 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 combinations are 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 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 stress drops to 14 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 10 sutures is recorded below:
8 ounces 11 ounces 16 ounces 13 ounces 9 ounces 13 ounces 101/2
ounces 12 ounces 11 ounces 14 ounces
The needle-suture combinations of the present invention may be used
by the surgeon employing conventional suturing technique as
illustrated in FIG. 1. After the suture has been placed, the needle
may be separated by a wrist motion snapping the needle off the end
of the suture as best illustrated in FIG. 2. The force required to
pull the needle from 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.
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