Surgical needle abstract
A surgical needle for use in suturing non-cutaneous soft tissues
of the body. The surgical needle includes a needle shaft and a needle
tip formed of a rigid material suitable for use inside the body.
The needle tip has a body portion integrally formed with and extending
from the needle shaft and is tapered along its length. The needle
tip is further provided with a blunt head which together with the
body portion defines a continuously smooth outer surface lacking
any sharp cutting edges. The blunt head is adapted to penetrate
muscle and fascia, muscle alone, adipose, pericostal tissue and
other non-cutaneous soft tissues or the body while at the same time
preventing skin penetration of the gloved hand of an operator.
Surgical needle claims
What is claimed is:
1. A surgical suture needle for use in directly piercing non-cutaneous
soft tissues of the body, comprising:
a needle shaft; and
a needle tip, said needle shaft and needle tip having a solid interior
lacking any lumen communicating with the exterior of said needle
and formed of a rigid material suitable for use inside the body,
said needle tip having a body portion integrally formed with and
extending from said needle shaft, said body portion being tapered
along the length thereof, said needle tip further having a blunt
head adapted to penetrate muscle and fascia, muscle alone, adipose,
pericostal tissue and other non-cutaneous soft tissues of the body
while preventing skin penetration of the gloved hand of an operator
and wherein said needle has a continuously smooth outer surface
lacking any sharp cutting edges.
2. The surgical needle of claim 1 wherein said blunt head has a
part spherical shape and a vertex which forms a portion of said
part spherical shape.
3. The surgical needle of claim 2 wherein said blunt head has a
diameter of curvature which is at least 25% of the diameter of said
needle shaft and said diameter of curvature is at least about 0.006".
4. The surgical needle of claim 3 wherein said blunt head having
a diameter of curvature in the range of 25% to 62% of the diameter
of said needle shaft.
5. The surgical needle of claim 3 wherein said diameter of curvature
of said needle tip is no greater than about 0.031".
6. The surgical needle of claim 1 wherein said needle shaft has
a generally flat pressed circular cross-section in order to facilitate
stability in a needle holder.
7. The surgical needle of claim 1 wherein said needle tip has a
generally circular cross-section.
8. The surgical needle of claim 1 wherein the diameter of said
needle shaft is in a range of about 0.026" to 0.050".
9. A surgical suture needle for use in directly piercing muscle
and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous
soft tissues of the body, comprising:
a needle shaft portion having a generally circular cross-section;
and
a needle tip portion having a generally circular cross-section,
said needle tip portion further having a body segment and a blunt
head, said body segment being tapered along the length thereof,
said blunt head having a part spherical shape and a vertex which
forms a portion of said part spherical shape, said blunt head having
a diameter of curvature which is at least 25% of the diameter of
said needle shaft to thereby prevent skin penetration of the gloved
hand of an operator, and wherein said needle tip portion and needle
shaft portion have a solid interior lacking any lumen communicating
with the exterior of said needle.
10. The surgical needle of claim 9 wherein said diameter of curvature
is in a range of 25% to 62% of the diameter of said needle shaft.
11. The surgical needle of claim 10 wherein the diameter of said
needle shaft is in a range of about 0.026" to 0.050".
12. The surgical needle of claim 10 wherein said diameter of curvature
of said needle tip is in a range between about 0.006" to about
0.031".
13. A taper point surgical suture needle for use in directly piercing
non-cutaneous soft tissues of the body, comprising:
a needle shaft; and
a means, located at the tip of said needle and extending integrally
from said needle shaft, for penetrating muscle and fascia, muscle
alone, adipose, pericostal tissue and other non-cutaneous soft tissues
of the body while preventing skin penetration of the gloved hand
of an operator, said needle shaft and tip means being formed of
a rigid material suitable for use inside the body, said tip means
having a tapered body portion integrally formed with and extending
from said needle shaft, said tip means further including a blunt
head integrally formed with and extending from said body portion,
said tip means having a continuously smooth outer surface lacking
any sharp cutting edges, and said tip means and needle shaft have
a solid interior lacking any lumen communicating with the exterior
of said needle.
14. The surgical needle of claim 13 wherein said blunt head has
a part spherical shape and a vertex which forms a portion of said
part spherical shape, said blunt head having a diameter of curvature
which in a range from about 50% to 62% of the diameter of said needle
shaft.
15. A surgical suture needle for use in directly piercing non-cutaneous
soft tissues of the body, comprising:
a needle shaft; and
a needle tip, said needle shaft and needle tip formed of a rigid
material suitable for use inside the body, said needle tip having
a body portion integrally formed with and extending from said needle
shaft, said body portion being tapered along the length thereof,
said needle tip further having a blunt head adapted to penetrate
muscle and fascia, muscle alone, adipose, pericostal tissue and
other non-cutaneous soft tissues of the body while preventing skin
penetration of the gloved hand of an operator, said blunt head having
a part spherical shape and a vertex which forms a portion of said
part spherical shape, said blunt head being formed so as to provide
a safety factor of at least 200% over a needle having 0% bluntness,
and wherein said needle tip and needle shaft have a solid interior
lacking any lumen communicating with the exterior of said needle.
16. The surgical needle of claim 15 wherein said blunt head is
formed so as to provide a safety factor of between about 200% to
800% over a needle having 0% bluntness.
Surgical needle description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of surgical
instruments and, more specifically, to surgical needles for suturing
wounds.
2. Description of the Art
In recent years, there has been an increasing awareness of the
problems associated with accidental sticking of medical personnel
with suturing and syringe needles. Before the advent of biological
warfare contaminants and the spreading of infectious health hazards
such as hepatitis B (HBV), human immunodeficiency virus (HIV) infection
and acquired immune deficiency syndrome (AIDS), the consequences
of sustaining a needle stick wound were not considered serious.
However, the knowledge that infectious diseases such as the AIDS
virus can be spread by an accidentally inflicted needle-stick from
a contaminated needle administered to a person having the AIDS virus
has done much to change this belief. Accordingly, there has been
an increasing amount of activity in the area of addressing this
problem. For example, U.S. Pat. No. 4828547 to Sahi et al. describes
a needle assembly containing a blunting member which is movable,
either by fluid flow through the needle or by mechanical pressure,
from a retracted position in which the blunting member does not
interfere with the puncture tip of the needle, to an extended position
attained after use in which the blunting member extends beyond the
punture tip and thereby blunts the needle. Further examples of shield
or guard type assemblies for syringe needles are disclosed in U.S.
Pat. Nos. 4883469 to Glazier and 4883471 to Braginetz et al.
While the devices disclosed in the above patents and other similar
type devices may be useful for hypodermic syringe needles which
are intended to be disposed of after a single "stick",
it is not a practicable solution for use with surgical needles since
such needles must make repeated "sticks" into the body.
While surgeons are highly trained and skilled individuals, the possibility
of an accidental stick from a surgical needle is still present.
Even a highly skilled surgeon can eventually become tired or, as
in trauma situations, in a hurry at the end of a long operation
and thus more prone to such an occurrence. Then too, it is not uncommon
that a less experienced individual in the operating room team is
assigned to close the wound.
The present invention is intended to decrease the potential transmission
of all infectious agents, including those referred to above, in
situations where accidental needle stick is the means for such transmission.
SUMMARY OF THE INVENTION
The present invention is a surgical needle for use in suturing
non-cutaneous soft tissues of the body. In a preferred embodiment
thereof, the present invention comprises a needle shaft and a needle
tip formed of a rigid material suitable for use inside the body.
The needle tip has a body portion integrally formed with and extending
from the needle shaft. The body portion is tapered along the length
thereof. The needle tip is further provided with a blunt head adapted
to penetrate muscle and fascia, muscle alone, adipose, pericostal
tissue and other non-cutaneous soft tissues of the body while at
the same time decreasing potential skin penetration of the gloved
hand of an operator and operating personnel such as surgeons, surgeon
assistants, scrub and circulating nurses, fabric care and housekeeping
personnel.
As additional features, the blunt head may have a part spherical
shape and a vertex which forms a portion of the part spherical shape.
Further, the blunt head may have a diameter of curvature which is
in a range from about 25% to 62% of the diameter of the needle shaft
and the needle tip may be formed so as to have a continuously smooth
outer surface lacking any sharp cutting edges.
Accordingly, it is an object of the present invention to provide
an improved surgical needle for use in suturing muscle and fascia,
muscle alone, adipose, pericostal tissue and other non-cutaneous
soft tissues of the body while at the same time significantly decreasing
the probibility of skin penetration of the gloved hand of an operator.
Related objects and advantages of the present invention will become
more apparent by reference to the following figures and detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph showing the relationship between penetration
force and needle bluntness using data obtained from Table I.
FIG. 2 is a graph showing the variation in difference in resistance
to penetration between gloved plantar skin and abdominal rectus
muscle as a function of needle bluntness using data obtained from
Table III.
FIG. 3 is a graph showing the variation in average penetration
force as a function of needle bluntness using data obtained from
Table III.
FIG. 4 is a side view of a preferred embodiment of the surgical
needle of the present invention.
FIG. 5 is an enlarged fragmentary view of the tip portion of the
surgical needle of FIG. 4.
FIG. 6 is an enlarged cross-sectional view taken along lines 6--6
in FIG. 4.
FIG. 7 is an alternative embodiment of the enlarged cross-sectional
view taken along lines 6--6 in FIG. 4.
FIG. 8 is an enlarged cross-sectional view taken along lines 8--8
in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
For the purposes of promoting an understanding of the principles
of the invention, reference will now be made to the embodiment illustrated
in the drawings and specific language will be used to describe the
same. It will nevertheless be understood that no limitation of the
scope of the invention is thereby intended, such alterations and
further modifications in the illustrated device, and such further
applications of the principles of the invention as illustrated therein
being contemplated as would normally occur to one skilled in the
art to which the invention relates.
As used herein, the term "bluntness" is intended to refer
to the relation between the diameter of curvature of the needle
point or vertex to the diameter of the needle shaft. For comparison
purposes, this relationship is expressed as a percentage. As an
example, a needle having 50% bluntness is intended to describe a
needle having a diameter of curvature at the vertex which is half
the diameter of the needle shaft. The term "diameter of curvature"
as used herein describes the hypothetical diameter of a fury spherical
surface coincident with the part spherical surface which forms the
vertex, or forwardmost point, of the needle. Thus, a totally sharp
needle, i.e., a needle having 0% bluntness, has zero curvature present
at the needle vertex.
A number of tests were conducted to determine whether there existed
a blunt needle point configuration which would permit relatively
easy penetration of soft non-cutaneous body tissues while providing
increased protection against an unintended stick of the gloved hand
of the operator. These included tests to determine the penetration
force as a function of "bluntness" in muscle/fascia and
in gloved palmar skin.
In a first series of tests, four groups of test results were obtained
corresponding to the following four test specimens: (1) abdominal
rectus muscle/fascia, (2) gloved palmar skin, (3) abdominal rectus
muscle/fascia vs. gloved plantar skin, and (4) intercostal muscle.
In each group of tests, eight needle point configurations were tested
having a bluntness of 0%, 25%, 37%, 50%, 62%, 75%, 87%, and 100%.
A sample set of six needles per each configuration were used for
each of the first, second and fourth groups of tests, making a total
of 48 needles for each of these groups of tests. In the third group
of tests, a sample set of twelve needles was used for each needle
configuration, making a total of 96 needles for this test group.
All needles were type T-20 surgical needles manufactured by the
Medical Divice Division of American Cyanamid Company of Danbury,
Conn. having a length of 1.891 inches, a wire diameter of 0.050
inches, and a curved shape having a radius of curvature along the
needle shaft of 0.656 inches and an included angle of 165 degrees.
The first group of test remits for the abdominal rectus muscle/fascia
was conducted as follows. The skin overlying the abdominal fascia
of a single cadaver was opened and retracted. The supra-umbilical
abdominal rectus muscle with its anterior and posterior sheaths
was then excised from the cadaver. Using this specimen, the force
of penetration was measured for each of the needles in the sample.
A total of three passes were made for each needle. In each pass,
penetration was made away from the midline of the specimen so that
the penetration sequence would always be fascia, muscle, then fascia.
In the second group of tests, skin from the palms of the same cadaver
used in the first series of tests was harvested. The area harvested
was bounded proximally by the skin crease at the wrist and distally
by the base of the digits. A standard latex procedure glove was
placed over the skin specimen in order to simulate unintended puncture
of the surgeon's hand. The penetration sequence was glove, epidermis,
dermis, and lastly, the back side of the latex glove. As with the
first group of tests, the force of penetration was measured for
each of the needles in the sample, with a total of three passes
being made for each needle.
The goal in the third group of tests was to directly compare the
penetration force of gloved skin as compared to that of abdominal
rectus muscle/fascia using the same needle. Since all usable palmar
skin had been harvested from the test cadaver in performing the
previous group of tests and another suitable cadaver was unavailable,
plantar skin was harvested from the test cadaver's feet. This skin
is similar to the skin of the palm in that both are thick skin areas.
Only the central non-weight bearing portion of the plantar skin
was used. The rectus muscle and fascia was harvested from the same
test cadaver from the umbilicus to just superior to the pubic bone.
The rectus muscle/fascia tissue was penetrated first, followed by
the gloved plantar skin. In order to assess the difference in penetration
force of palmar skin versus plantar skin, several passes were made
through some remaining palmar skin after the plantar skin had been
penetrated. The results obtained indicated that the penetration
force was approximately the same for the two skin specimens using
the sharp (0% bluntness) needles, with the plantar penetration force
increasing as the bluntness fo the needle increased (approximately
twice the penetration force was necessary with a 62% dull needle).
Again, the force of penetration was measured for each of the needles
in the sample. In this group of tests, one pass was made into both
specimens with each needle.
For the fourth group of tests, intercostal muscle was harvested
from the same cadaver front interspaces 3 through 5 at the mid-clavicular
line. The specimen blocks also consisted of the pleural lining of
the chest (parietal pleura). The force of penetration was measured
for each of the needles in the sample, with a total of three passes
being made for each needle.
The data set forth in Table I is shown in graph form in FIG. 1
wherein resistance to penetration is plotted along the vertical
axis and degree of tip bluntness, expressed as a percentage, is
plotted along the horizontal axis. Proceeding from uppermost to
lowest, the four curves in FIG. 1 correspond to gloved plantar skin,
gloved palmar skin, abdominal rectus muscle, and intercostal muscle,
respectively. As can be seen with reference to FIG. 1 at all bluntness
settings both gloved palmer skin and gloved plantar skin exhibit
a greater resistance to penetration than do abdominal rectus fascia/muscle
or intercostal fascia/muscle. Further, as can be seen with reference
to FIG. 2 the difference in penetration force between gloved skin
(plantar) and fascia/muscle (abdominal rectus) remains about the
same for needle bluntness in the range between about 0 and 25%.
However, as the degree of needle bluntness approaches about 25%,
the difference in penetration force between gloved skin (palmar)
and fascia/muscle (abdominal rectus) beans to increase. This difference
in penetration force continues to increase throughout the remaining
range of needle bluntness. It is also perceived from these tests
that at bluntness settings greater than about 62% the resistance
to penetration of the type needle becomes sufficiently great in
abdominal rectus and intercostal fascia/muscle that usage would
be disfavored.
In a second series of tests, needles having bluntness settings
in a range from 25% to 62% were tested in comparison with totally
sharp needles having 0% bluntness. The specific bluntness settings
tested were 0%, 25%, 37%, 50%, and 62%. Thirty-two penetration measurements
were taken at each bluntness setting, broken into four test series
identified as A, B, C and D. Each test series was done on a single
cadaver. For each test, a needle was passed through muscle fascia
and the required penetration force was recorded. Thus, this series
of tests involved 160 needles. Table II shows the raw data obtained
while Table III presents a statistical summary of the results of
these tests. FIG. 3 is a graph showing the variation in average
penetration force as a function of needle bluntness using data obtained
from Table III. In Table III "Avg" refers to the average
force of penetration expressed in grams of the thirty-two tests
conducted at each bluntness setting, while "SD" refers
to the standard deviation of the test results.
It is perceived that the degree of safety provided to an operator
by a particular needle configuration is directly related to the
magnitude of difference in the penetration force needed to pierce
the target body tissues and the gloved hand of the operator. As
is indicated by the data in Table III, a totally sharp needle having
0% bluntness requires an average of 172.5 grams greater penetration
force to penetrate gloved skin as compared to muscle fascia. This
"safety factor" of 172.5 grams is of course insufficient
in many instances in preventing accidental sticks of the gloved
hand of the operator. The Table III results show that needles having
a bluntness in the 25-62% range exhibit a much greater magnitude
of difference in the penetration force needed to pierce the target
body tissues and the gloved hand of the operator than sharp needles
(i.e., needles having 0% bluntness).
A preferred embodiment of the surgical suture needle or the present
invention, incorporating the desired safety characteristics is generally
indicated at 10 in FIGS. 4 and 5. The needle 10 has a shaft portion
11 having a uniform outer diameter, and a tip portion 12 integrally
formed with shaft portion 11 and extending distally there from.
In order to provide stability and control of the needle 10 during
use, the shaft portion 11 may have a flat pressed circular cress
section such as shown in FIG. 6 or, alternatively, a modified square
cross sectional shape such as shown in FIG. 7. In the needle 10
of FIG. 4 the shaft portion 11 is curved and possesses a constant
radius of curvature. This configuration is, however, not critical
to the present invention and shaft portion 11 may therefore assume
any straight and/or curved configuration which is considered suitable
for the particular purpose that is intended. Both the shaft portion
11 and tip portion 12 are rigidly formed of a suitable material
for suture needle use inside the body, such as surgical grade steel.
The needle tip portion 12 has an essentially circular cross sectional
shape, as shown in FIG. 8 and a tapered body 14. The needle tip
portion 12 terminates in a blunt head 16 which is configured to
permit piercing of muscle and fascia, muscle alone, adipose, pericostal
tissue and other non-cutaneous soft tissues of the body While preventing
skin penetration of the gloved hand of an operator. As can be best
appreciated with reference to FIG. 5 head 16 preferably has a part
spherical shape which encompasses vertex 17 of tip portion 12. Other
curved shapes may also be employed as suitable configurations for
head 16 so long as there are no sharp edge surfaces.
It should be noted that the surgical needle of the present invention
is specifically designed such that it is not suitable for suturing
cutaneous tissues. Accordingly, based upon the test results obtained,
it is considered important that blunt head 16 have a minimum diameter
of curvature which is at least 25% of the diameter of the needle
shaft portion 11 and a maximum diameter of curvature which no greater
than about 62% of the diameter of the needle shaft. Within this
range, it is perceived that needles having a bluntness which is
toward the higher end of the range will be especially preferred
as they offer a greater safety factor while still being acceptable
for use. Further, the diameter of the needle shaft should be in
a range of about 0.026" to 0.050" with the diameter of
curvature of the needle tip ranging between about 0.006" to
about 0.031". In addition, it is considered critical that the
entire needle tip portion has a continuously smooth outer surface
lacking any discontinuities or sharp cutting edges.
In practice, the surgical suture needle of the present invention
may be used to close non-cutaneous soft tissues of the body employing
the same techniques used with conventional suture needles. However,
since the cutaneous tissues of the wound cannot be closed with the
blunt tip needle, another closing technique must be used to complete
the wound closure. This does not pose a problem, however, in that
it is quite common to employ different closing techniques for closing
the cutaneous and non-cutaneous tissues in a wound. For example,
the needle of the present invention may be used to close the non-cutaneous
tissues while final closure of the cutaneous tissues may be accomplished
by conventional stapling techniques.
It is perceived that the blunt needle off the present invention
may, in addition to reducing the risk of infectious disease transmission
by reducing the risk of an accidental needle stick, also serve to
reduce the risk of needle contamination by reducing the amount of
bleeding caused by the needle. Decreased bleeding occurs because
the blunt needle is more likely to simply push blood vessels aside
rather than penetrate them as it is being advanced in the body.
While the invention has been illustrated and described in detail
in the drawings and foregoing description, the same is to be considered
as illustrative and not restrictive in character, it being understood
that only the preferred embodiment has been shown and described
and that all changes and modifications that come within the spirit
or the invention are desired to be protected. |