Suture needle abstract
In the production of a suture needle, a distal end portion of an
elongated material is ground into a generally quadrangular pyramid
shape. Then, the distal end portion of the elongated material is
further ground into a generally triangular-pyramid shape, so that
the distal or foremost end of the elongated material is positively
pointed. The suture needle has four main surfaces and an auxiliary
surface. The above triangular-pyramid shape is defined by two of
the main surfaces and the auxiliary surface.
Suture needle claims
What is claimed is:
1. A suture needle including a proximal end portion serving as
a gut-attaching portion, a distal end portion whose cross-sectional
area decreases progressively toward a distal end of said suture
needle, and a main body portion lying between said proximal end
portion and said distal end portion, said distal end portion including:
(a) first, second, third and fourth main surfaces formed on an
outer periphery of said distal end portion and arranged sequentially
around the periphery of said distal end portion, said first and
second main surfaces intersecting each other to form a first main
edge, said second and third main surfaces intersecting each other
to form a second main edge, said third and fourth main surfaces
intersecting each other to form a third main edge, said first and
second main surfaces intersecting each other at an acute angle so
that said first main edge serves as a main cutting edge, said third
and fourth main surfaces intersecting each other at an acute angle
so that said third main edge also serves as another main cutting
edge;
(b) an auxiliary surface formed on said distal end portion of said
suture needle, said auxiliary surface intersecting said first, second,
third and fourth main surfaces to form first, second, third and
fourth auxiliary edges, respectively, said second and third auxiliary
edges serving as auxiliary cutting edges which are sharper than
said main cutting edges, said auxiliary surface intersecting said
first, second and third main edges at their front ends to form first,
second and third intersecting points, respectively, said second
intersecting point being disposed forwardly of said first and third
intersecting point, and serving as a foremost point of said suture
needle, said foremost point being connected to said first main edge
via said second auxiliary edge, and also being connected to said
third main edge via said third auxiliary edge, that portion of said
distal end portion disposed forwardly of said first and third intersecting
points having a triangular-pyramid shape defined by said second
and third main surfaces and said auxiliary surface, and that portion
of said distal end portion disposed rearwardly of said first and
third intersecting points having a pentagonal cross-sectional shape
defined by said first, second, third and fourth main surfaces and
said auxiliary surface, in which said first and fourth auxiliary
edges are spaced from each other by said auxiliary surface lying
therebetween.
2. A suture needle including a proximal end portion serving as
a gut-attaching portion, a distal end portion whose cross-sectional
area decreases progressively toward a distal end of said suture
needle, and a main body portion lying between said proximal end
portion and said distal end portion, said distal end portion including:
(a) first, second, third and fourth main surfaces formed on an
outer periphery of said distal end portion and arranged sequentially
around the periphery of said distal end portion, said first and
second main surfaces intersecting each other to form a first main
edge, said second and third main surfaces intersecting each other
to form a second main edge, said third and fourth main surfaces
intersecting each other to form a third main edge, said first and
second main surfaces intersecting each other at an acute angle so
that said first main edge serves as a main cutting edge, said third
and fourth main surfaces intersecting each other at an acute angle
so that said third main edge also serves as another main cutting
edge;
(b) an auxiliary surface formed on said distal end portion of said
suture needle, said auxiliary surface intersecting said first, second,
third and fourth main surfaces to form first, second, third and
fourth auxiliary edges, respectively, said second and third auxiliary
edges serving as auxiliary cutting edges which are sharper than
said main cutting edges, said auxiliary surface intersecting said
first, second and third main edges at their front ends to form first,
second and third intersecting points, respectively, said second
intersecting point being disposed forwardly of said first and third
intersecting point, and serving as a foremost point of said suture
needle, said foremost point being connected to said first main edge
via said second auxiliary edge, and also being connected to said
third main edge via said third auxiliary edge, that portion of said
distal end portion disposed forwardly of said first and third intersecting
points having a triangular-pyramid shape defined by said second
and third main surfaces and said auxiliary surface, and that portion
of said distal end portion disposed rearwardly of said first and
third intersecting points having a pentagonal cross-sectional shape
defined by said first, second, third and fourth main surfaces and
said auxiliary surface;
wherein said main body portion and said distal end portion have
a pair of base surfaces substantially parallel to each other, one
of said pair of base surfaces intersecting said second and third
main surfaces at said distal end portion, and the other base surface
intersecting the first and fourth main surfaces at said distal end
portion; and
wherein the angle of intersection between said first and second
main surfaces is generally equal to the angle of intersection between
said third and fourth main surfaces, said first and fourth auxiliary
edges being spaced from each other by said auxiliary surface lying
therebetween, said auxiliary surface intersecting said other base
surface to form a fifth auxiliary edge extending generally perpendicular
to the axis of said distal end portion, said fifth auxiliary edge
being disposed rearwardly of the rear end of said second main edge,
that portion of said distal end portion lying between said first
and third intersecting points and the rear end of said second main
edge having a pentagonal cross-sectional shape defined by said auxiliary
surface and said first, second, third and fourth main surfaces,
that portion of said distal end portion lying between the rear end
of said second main edge and said fifth auxiliary edge having a
hexagonal cross-sectional shape defined by said one base surface,
said auxiliary surface and said first, second, third and fourth
main surfaces, and that portion of said distal end portion disposed
rearwardly of said fifth auxiliary edge having a hexagonal cross-sectional
shape defined by said pair of base surfaces and said first, second,
third and fourth main surfaces.
3. A method of producing a suture needle comprising the steps of:
(a) effecting main grinding by which a distal end portion of an
elongated material is ground from four directions so as to decrease
the cross-sectional area of said distal end portion progressively
toward a distal end of said elongated material, thereby forming
on an outer periphery of said distal end portion first, second,
third and fourth main surfaces arranged sequentially around the
periphery of said distal end portion, said first and second main
surfaces intersecting each other to form a first main edge, said
second and third main surfaces intersecting each other to form a
second main edge, said third and fourth main surfaces intersecting
each other to form a third main edge, and at least one of said first,
second and third main edges serving as a cutting edge; and
(b) subsequently effecting auxiliary grinding by which that portion
of said distal end portion including front ends of said first, second,
third and fourth main edges is ground to form an auxiliary surface,
said auxiliary surface intersecting said first, second, third and
fourth main surfaces to form first, second, third and fourth auxiliary
edges, respectively, said auxiliary surface intersecting said first,
second and third main edges at their front ends to form first, second
and third intersecting points, respectively, said second intersecting
point being disposed forwardly of said first and third intersecting
points, and serving as a foremost point of said suture needle, and
said foremost point being connected to said first main edge via
said second auxiliary edge, and also being connected to said third
main edge via said third auxiliary edge.
4. A method of producing a suture needle comprising the steps of:
(a) pressing a distal end portion and a main body portion of an
elongated material of a generally circular cross-section into a
flattened cross-sectional shape to thereby form a pair of parallel
base surfaces on opposite sides of said flattened portions;
(b) effecting main grinding by which said distal end portion of
said elongated material is ground from four directions so as to
decrease the cross-sectional area of said distal end portion progressively
toward a distal end of said elongated material, thereby forming
on an outer periphery of said distal end portion first, second,
third and fourth main surfaces arranged sequentially around the
periphery of said distal end portion, said second and third main
surfaces intersecting one of said pair of base surfaces, said first
and fourth main surfaces intersecting the other base surface, said
first and second main surfaces intersecting each other at an acute
angle to form a first main edge, said second and third main surfaces
intersecting each other at an obtuse angle to form a second main
edge, said third and fourth main surfaces intersecting each other
at an acute angle to form a third main edge, said first and fourth
main surfaces intersecting each other at an obtuse angle to form
a fourth main edge, and said first and third main edges serving
cutting edges, respectively; and
(c) subsequently effecting auxiliary grinding by which that portion
of said distal end portion including front ends of said first, second,
third and fourth main edges is ground to form an auxiliary surface,
said auxiliary surface intersecting said first, second, third and
fourth main surfaces to form first, second, third and fourth auxiliary
edges, respectively, said auxiliary surface intersecting said first,
second and third main edges at their front ends to form first, second
and third intersecting points, respectively, said second intersecting
point being disposed forwardly of said first and third intersecting
points, and serving as a foremost point of said suture needle, and
said foremost point being connected to said first main edge via
said second auxiliary edge, and also being connected to said third
main edge via said third auxiliary edge.
5. A method according to claim 4 in which said auxiliary grinding
is effected in such a manner that said auxiliary surface intersects
said fourth main edge.
6. A method according to claim 4 in which said auxiliary grinding
is effected along said fourth main edge so as to remove said fourth
main edge, so that said auxiliary surface intersects said other
base surface.
Suture needle description
BACKGROUND OF THE INVENTION
This invention relates to a suture needle having cutting edges
and also to a method of producing such a suture needle.
There are well known suture needles whose distal end portion has
a triangular, trapezoidal or rhombic cross-section, and has one
or two cutting edges. Such various suture needles are used in accordance
with the purpose of the surgical operation.
In order that the suture needle can have a good penetrating ability,
the distal or foremost end thereof must be pointed. In a suture
needle having a triangular cross-section as disclosed in Japanese
Patent Publication No. 26783/89 its distal end portion is ground
to form three ground surfaces so as to decrease the cross-sectional
area of the distal end portion progressively toward the distal end
of the suture needle. In this case, the foremost end of the suture
needle is naturally pointed.
In a suture needle whose distal end portion has a quadrangular
cross-section, when the distal end portion is to be ground to form
four ground surfaces so as to decrease its cross-sectional area,
the foremost end of the suture needle can be pointed only by precisely
controlling the amount of grinding of each ground surface. For example,
in a suture needle having a rhombic cross-section and having a pair
of cutting edges, as disclosed in U.S. Pat. Nos. 1506262 and 3238942
the foremost end of the suture needle can be pointed when the amounts
of grinding of the four ground surfaces are the same, and the pair
of cutting edges intersect each other at this point. Otherwise,
instead of such a pointed end, a short edge generally perpendicularly
intersecting the longitudinal axis of the distal end portion is
formed, and this edge intersects the cutting edges at its opposite
end. In this case, the penetrating ability is worsened. Further,
since the difference between the amount of actual grinding of each
ground surface and the intended amount of grinding thereof varies
from one suture needle to another, there occur variations in the
penetrating ability. For controlling the grinding amount so as to
form the foremost end of the suture needle into a pointed shape,
the narrower the suture needle is, the higher precision is required,
and the cost is increased.
Referring to other prior art, Japanese Patent Publication No. 57337/85
discloses a suture needle having a distal end portion pressed into
a flattened configuration, and first, second and third ground surfaces
are formed at this distal end portion, the second and third ground
surfaces intersecting the first ground surface at an acute angle
to form cutting edges. The cross-sectional area of the distal end
portion of the suture needle is decreasing progressively toward
the distal end thereof. The second and third ground surfaces do
not intersect each other at that portion of the suture needle remote
from the distal end thereof, and therefore this portion has a trapezoidal
cross-section. The second and third ground surfaces intersect each
other at that portion of the suture needle near the distal end thereof,
and therefore this portion has a triangular cross-section. Further,
an auxiliary ground surface is formed at the distal end portion
of the suture needle, and this auxiliary ground surface intersects
the second and third ground surfaces to make the foremost end pointed.
The auxiliary ground surface serves to make the foremost point less
sharp.
U.S. Pat. No. 4128351 discloses a suture needle in which a distal
end portion of the suture needle is formed into a triangular cross-section
by three ground surfaces. The angle between one ground surface and
the axis of the distal end portion is greater than the angle of
each of the other two ground surfaces and the axis of the distal
end portion.
Japanese Utility Model Publication No. 6885/86 discloses a technique
by which the grinding is carried out along a pair of cutting edges
of a suture needle of a triangular cross-section, thereby forming
another pair of cutting edges.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a suture needle in
which its foremost end is pointed while maintaining advantages achieved
by a generally square cross-sectional shape of its distal end portion,
thereby achieving a good penetrating ability.
Another object of the invention is to provide a method of producing
such a suture needle.
According to one aspect of the present invention, there is provided
a suture needle including a proximal end portion serving as a gut-attaching
portion, a distal end portion whose cross-sectional area decreases
progressively toward a distal end of the suture needle, and a main
body portion lying between the proximal end portion and the distal
end portion, the distal end portion including:
(a) first, second, third and fourth main surfaces formed on an
outer periphery of the distal end portion and arranged sequentially
around the periphery of the distal end portion, the first and second
main surfaces intersecting each other to form a first main edge,
the second and third main surfaces intersecting each other to form
a second main edge, the third and fourth main surfaces intersecting
each other to form a third main edge, and at least one of the first,
second and third main edges serving as a cutting edge; and
(b) an auxiliary surface formed on the distal end portion of the
suture needle, the auxiliary surface intersecting the first, second,
third and fourth main surfaces to form first, second, third and
fourth auxiliary edges, respectively, the auxiliary surface intersecting
the first, second and third main edges at their front ends to form
first, second and third intersecting points, respectively, the second
intersecting point being disposed forwardly of the first and third
intersecting point, and serving as a foremost point of the suture
needle, the foremost point being connected to the first main edge
via the second auxiliary edge, and also being connected to the third
main edge via the third auxiliary edge, that portion of the distal
end portion disposed forwardly of the first and third intersecting
points having a triangular-pyramid shape defined by the second and
third main surfaces and the auxiliary surface, and that portion
of the distal end portion disposed rearwardly of the first and third
intersecting points having a pentagonal cross-sectional shape defined
by the first, second, third and fourth main surfaces and the auxiliary
surface.
According to another aspect of the invention, there is provided
a method of producing a suture needle comprising the steps of:
(a) effecting main grinding by which a distal end portion of an
elongated material is ground from four directions so as to decrease
the cross-sectional area of the distal end portion progressively
toward a distal end of the elongated material, thereby forming on
an outer periphery of the distal end portion first, second, third
and fourth main surfaces arranged sequentially around the periphery
of the distal end portion, the first and second main surfaces intersecting
each other to form a first main edge, the second and third main
surfaces intersecting each other to form a second main edge, the
third and fourth main surfaces intersecting each other to form a
third main edge, and at least one of the first, second and third
main edges serving as a cutting edge; and
(b) subsequently effecting auxiliary grinding by which that portion
of the distal end portion including front ends of the first, second,
third and fourth main edges is ground to form an auxiliary surface,
the auxiliary surface intersecting the first, second, third and
fourth main surfaces to form first, second, third and fourth auxiliary
edges, respectively, the auxiliary surface intersecting the first,
second and third main edges at their front ends to form first, second
and third intersecting points, respectively, the second intersecting
point being disposed forwardly of the first and third intersecting
points, and serving as a foremost point of the suture needle, and
the foremost point being connected to the first main edge via the
second auxiliary edge, and also being connected to the third main
edge via the third auxiliary edge.
According to a further aspect of the invention, there is provided
a method of producing a suture needle comprising the steps of:
(a) pressing a distal end portion and a main body portion of an
elongated material of a generally circular cross-section into a
flattened cross-sectional shape to thereby form a pair of parallel
base surfaces on opposite sides of the flattened portions;
(b) effecting main grinding by which the distal end portion of
the elongated material is ground from four directions so as to decrease
the cross-sectional area of the distal end portion progressively
toward a distal end of the elongated material, thereby forming on
an outer periphery of the distal end portion first, second, third
and fourth main surfaces arranged sequentially around the periphery
of the distal end portion, the second and third main surfaces intersecting
one of the pair of base surfaces, the first and fourth main surfaces
intersecting the other base surface, the first and second main surfaces
intersecting each other at an acute angle to form a first main edge,
the second and third main surfaces intersecting each other at an
obtuse angle to form a second main edge, the third and fourth main
surfaces intersecting each other at an acute angle to form a third
main edge, the first and fourth main surfaces intersecting each
other at an obtuse angle to form a fourth main edge, and the first
and third main edges serving cutting edges, respectively; and
(c) subsequently effecting auxiliary grinding by which that portion
of the distal end portion including front ends of the first, second,
third and fourth main edges is ground to form an auxiliary surface,
the auxiliary surface intersecting the first, second, third and
fourth main surfaces to form first, second, third and fourth auxiliary
edges, respectively, the auxiliary surface intersecting the first,
second and third main edges at their front ends to form first, second
and third intersecting points, respectively, the second intersecting
point being disposed forwardly of the first and third intersecting
point, and serving as a foremost point of the suture needle, and
the foremost point being connected to the first main edge via the
second auxiliary edge, and also being connected to the third main
edge via the third auxiliary edge.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a bar subjected to pressing which
is one step of a suture needle-producing method of the present invention;
FIG. 2 is a plan view of a distal end portion of the bar subjected
to main grinding;
FIG. 3 is a view as seen from arrow III of FIG. 2;
FIG. 4 is a view as seen from arrow IV of FIG. 2;
FIGS. 5 to 8 are cross-sectional views taken along the lines Qa,
Qb, Qc and Qd of FIG. 3 respectively;
FIG. 9 is an enlarged plan view of the distal end portion of the
bar subjected to auxiliary grinding after the ideal main grinding
is applied to the distal end portion;
FIG. 10 is a view as seen from arrow X of FIG. 9;
FIG. 11 is a view as seen from arrow XI of FIG. 9;
FIGS. 12 to 14 are cross-sectional views taken along the lines
Ra, Rb and Rc of FIG. 10 respectively;
FIG. 15 is an enlarged plan view of the distal end portion of the
bar subjected to auxiliary grinding after the non-ideal main grinding
is applied to the distal end portion;
FIG. 16 is a view as seen from arrow XVI of FIG. 15;
FIG. 17 is a view as seen from arrow XVII of FIG. 15;
FIGS. 18 to 20 are cross-sectional views taken along the lines
Sa, Sb and Sc of FIG. 15 respectively;
FIG. 21 is a perspective view of the suture needle in its finished
form;
FIG. 22 is a front-elevational view of a distal end portion of
a modified suture needle of the invention;
FIG. 23 is a view as seen from arrow XXIII of FIG. 22;
FIGS. 24 to 26 are cross-sectional views taken along the lines
Ta, Tb and Tc of FIG. 23 respectively; and
FIG. 27 is a view similar to FIG. 12 but showing another modified
form of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
One preferred embodiment of a suture needle-producing method of
the present invention will now be described with reference to the
drawings. The suture needle produced by the method of this embodiment
is used for an operation on the eye. A hole 1a for attaching a suture
gut thereto is formed in one end portion (proximal end portion)
1 of a cross-sectionally circular bar (elongated material) A, as
shown in FIG. 1. Then, except for the proximal end portion 1 the
bar A (that is, a major body portion 2 and a distal end portion
3) is pressed into a flattened cross-sectional shape. As a result,
the major body portion 2 and the distal end portion 3 have flat
base surfaces 5a and 5b parallel to each other.
Then, as shown in FIGS. 2 to 8 main grinding is applied to the
distal end portion 3. More specifically, the distal end portion
3 is ground from four directions to be formed into a tapered configuration,
so that four (1st to 4th) main surfaces 10a, 10b, 10c and 10d are
formed on the distal end portion and are arranged sequentially around
the periphery of the distal end portion 3. The first and second
main surfaces 10a and 10b are formed at one lateral edge portion
of the distal end portion 3 whereas the third and fourth main surfaces
10c and 10d are formed at the other lateral edge portion of the
distal end portion 3. The first and second main surfaces 10a and
10b intersect each other at an acute angle (for example, 40.degree.
to 45.degree. ) to form a first main edge 11a. Similarly, the third
and fourth main surfaces 10c and 10d intersect each other at the
same acute angle to form a third main edge 11c. The first main edge
11a and the third main edge 11c serve as cutting edges, respectively.
The second main surface 10b and the third main surface 10c intersect
each other at an obtuse angle (135.degree. to 140.degree.) in the
vicinity of a distal end 4 of the bar A, thereby forming a second
main edge 11b. Similarly, the first main surface 10a and the fourth
main surface 10d intersect each other at the same obtuse angle in
the vicinity of the distal end 4 thereby forming a fourth main
edge 11d. Therefore, that portion of the bar A where the four main
surfaces 10a to 10d intersect one another has a generally quadrangular
pyramid shape, and has the cross-section of a flattened rhombic
shape as shown in FIGS. 7 and 8.
At that portion of the bar A remote from its distal end 4 the
second main surface 10b and the third main surface 10c intersect
one base surface 5a to form edges 12b and 12c, respectively. The
edges 12b and 12c intersect each other at the rear end of the second
main edge 11b. The first main surface 10a and the fourth main surface
10d intersect the other base surface 5b to form edges 12a and 12d,
respectively. The edges 12a and 12d intersect each other at the
rear end of the fourth main edge 11d. That portion of the distal
end portion 3 disposed rearwardly of the rear ends of the second
and fourth main edges 11b and 11d has a flattened hexagonal shape
defined by the pair of base surfaces 5a and 5b and the four main
surfaces 10a to 10d, as shown in FIG. 6.
Each of the four main surfaces 10a to 10d is convexly curved outwardly,
and the main edges 11a to 11d as well as the edges 12a to 12d are
also curved. However, the main surfaces 10a to 10d may be flat,
and the main edges 11a to 11d as well as the edges 12a to 12d may
be straight.
Next, the shape of the distal end 4 obtained by the above main
grinding will now be described in detail. If the main grinding is
carried out so ideally that the amounts of grinding of the four
main surfaces 10a to 10d can be equal to one another, the four main
surfaces 10a to 10d equally decrease in width progressively toward
the distal end 4 and finally converge on a point 13 as shown in
phantom in FIGS. 9 to 11.
If the amounts of grinding of the four main surfaces 10a, 10b,
10c and 10d are slightly different, for example, if the amount of
grinding of one main surface 10c is larger than those of the other
three main surfaces 10a, 10b and 10d with the result that the main
surface 10c is disposed inwardly of its ideal position, as shown
in phantom in an exaggerated manner in FIG. 18 the point 13 is
not formed on the distal end 4. In this case, as shown in phantom
in FIGS. 15 to 17 a short edge 14 generally perpendicularly intersecting
the axis of the distal end portion 3 is formed. This edge 14 intersects
the first and second main edges 11a and 11b at its one end, and
also intersects the third and fourth main edges 11c and 11d at its
other end. The existence of this edge 14 adversely affects the penetrating
ability of the suture needle (final product).
In this embodiment, after the four main surfaces 10a to 10d are
formed by the above main grinding, auxiliary grinding is carried
out regardless of whether the distal end 4 has the ideal shape with
the point 13 or the shape with the edge 14. More specifically, that
portion of the bar A including the front ends of the four main edges
11a to 11d (that is, that portion in the vicinity of the front end
4) is slightly ground to form an auxiliary surface 15 as shown
in FIGS. 9 to 11 or FIGS. 15 to 17 thereby removing the above point
13 or the above edge 14.
The auxiliary surface 15 is inclined relative to the axis of the
distal end portion 3. The auxiliary surface 15 intersects the second
and third main surfaces 10b and 10c at acute angles to form second
and third auxiliary edges 16b and 16c. The auxiliary surface 15
intersects the first and fourth main surfaces 10a and 10d at obtuse
angles to form first and fourth auxiliary edges 16a and 16d.
The auxiliary surface 15 intersects the four main edges 11a, 11b,
11c and 11d to form 1st to 4th intersecting points 18a, 18b, 18c
and 18d. The second intersecting point 18b is disposed forwardly
of the first and third intersecting points 18a and 18c, and serves
as a foremost point of the suture needle as later described. The
fourth intersecting point 18d is disposed rearwardly of the first
and third intersecting points 18a and 18c. The foremost point 18b
is connected to the first and third main edges 11a and 11c via the
acute second and third auxiliary edges 16b and 16c.
That portion of the distal end portion 3 disposed forwardly of
the first and third intersecting points 18a and 18c has a triangular-pyramid
shape defined by the second and third main surfaces 10b and 10c
and the auxiliary surface 15 as shown in FIG. 14 or FIG. 20. Namely,
this portion has a triangular cross-section, and decreases in cross-sectional
area progressively toward the point 18b. That portion of the distal
end portion 3 lying axially between the first and second intersecting
points 18a and 18c and the fourth intersecting point 18d has a pentagonal
cross-sectional shape defined by the four main surfaces 10a to 10d
and the auxiliary surface 15 as shown in FIG. 13 or FIG. 19. That
portion of the distal end portion 3 (where the auxiliary surface
15 is not provided) lying axially between the fourth intersecting
point 18d and the rear ends of the second and fourth main edges
11b and 11d has a rhombic cross-sectional shape defined by the four
main surfaces 10a to 10 d, as shown in FIG. 12 or FIG. 18. Incidentally,
if the main grinding for forming the main surfaces 10a to 10d is
carried out not ideally with the result that the first and third
intersecting points 18a and 18c are displaced relative to each other
in the direction of the axis of the distal end portion 3 that portion
of the distal end portion 3 lying between the intersecting points
18a and 18c has a square cross-section.
After the above auxiliary grinding is finished, the bar A is bent
into a curved shape to obtain the suture needle 50 as shown in FIG.
21. In this case, the second main edge 11b is disposed on the inner
side of the curved suture needle 50 and the fourth main edge 11d
is disposed on the outer side of the curved suture needle 50. Then,
the suture needle 50 is subjected to electrolytic polishing or chemical
polishing if necessary, and then one end portion of the suture gut
is inserted into the hole 1a, and the proximal end portion 1 of
the suture needle 50 is deformed or compressed to fixedly hold the
suture gut.
The distal end portion 3 of the suture needle of this embodiment
is generally analogous in shape to the distal end portion of the
above-mentioned conventional suture needle having a rhombic cross-section
and having a pair of cutting edges. Therefore, the distal end portion
3 has the function similar to that of the distal end portion of
this conventional suture needle. More specifically, the distal end
portion 3 can advance while cutting the tissue by the pair of cutting
edges 11a and 11c. That portion of the distal end portion 3 disposed
forwardly of the intersecting points 18a and 18c is formed into
a triangular-pyramid shape by providing the auxiliary surface 15
and therefore the foremost end of the suture needle 50 can be positively
formed into the point 18b. This allows the suture needles to penetrate
smoothly. Although the suture needle 50 is slightly inferior in
penetrating ability to the type of suture needle in which the four
main surfaces 10a to 10d are ideally formed, the difference in penetrating
ability between the two is negligibly small.
The point 18b of the suture needle 50 is formed in the vicinity
of the axis of the distal end portion 3 and is connected to the
cutting edges 11a and 11c via the acute auxiliary edges 16b and
16c. With this arrangement, the good penetrating ability can be
ensured. Further, the point 18b is formed on the front end of the
second main edge 11b and is spaced generally equidistantly from
the cutting edges 11a and 11c, and therefore during the surgical
operation, the suture needle 50 is prevented from being displaced
in the tissue in a direction generally transverse to the cutting
edges, thus providing a good operability of the suture needle 50.
The above method of forming the point 18b by the provision of the
auxiliary surface 15 can make the manufacturing cost lower as compared
with the case where the main surfaces 10a to 10d are highly precisely
controlled.
FIGS. 22 to 26 shows another embodiment of the invention. In this
embodiment, the same main grinding as described above for the preceding
embodiment is carried out. Those portions of this embodiment, formed
by the main grinding and corresponding to those portions of the
preceding embodiment, are designated respectively by identical reference
numerals used in the preceding embodiment, and explanation thereof
is omitted. In an auxiliary grinding operation, the grinding is
carried out along a fourth main edge 11d to form an auxiliary surface
115. By this grinding, a point or an edge 14 on a distal end 4 is
removed, and the fourth main edge 11d is also removed. The auxiliary
surface 115 intersects a base surface 5b at its rear end to form
a fifth auxiliary edge 116e generally perpendicularly intersecting
the axis of the distal end portion 3. The auxiliary surface 115
intersects second and third main surfaces 10b and 10c to form acute
second and third auxiliary edges 116b and 116c. The auxiliary edges
116b and 116c are acuter than the auxiliary edges 16b and 16c of
the preceding embodiment. Also, the auxiliary surface 115 intersects
first and fourth main surfaces 10a and 10d to form obtuse first
and fourth auxiliary edges 116a and 116d. The first auxiliary edge
116a and the fourth auxiliary edge 116d are spaced from each other
by the auxiliary surface 115 lying therebetween, and are generally
parallel to each other. The auxiliary surface 115 intersects first,
second and third main edges 11a, 11b and 11c to form first, second
and third intersecting points 118a, 118b and 118c. The second intersecting
point 118b serves as a foremost point of the suture needle.
That portion of the distal end portion 3 disposed forwardly of
the first and third intersecting points 118a and 118c has a triangular-pyramid
shape defined by the second and third main surfaces 10b and 10c
and the auxiliary surface 115 and has a triangular cross-section
as shown in FIG. 26. That portion of the distal end portion 3 lying
between the first and third intersecting points 118a and 118c and
a rear end 11b' of the second main edge 11b has a pentagonal cross-sectional
shape defined by the four main surfaces 10a to 10d and the auxiliary
surface 115 as shown in FIGS. 24 and 25. That portion of the distal
end portion 3 lying between the rear end 11b' of the second main
edge 11b and the fifth auxiliary edge 116e has a hexagonal cross-sectional
shape defined by one base surface 5a, the auxiliary surface 115
and the four main surfaces 10a to 10d. That portion of the distal
end portion 3 disposed rearwardly of the fifth auxiliary edge 116e
has a hexagonal cross-sectional shape defined by the pair of base
surfaces 5a and 5b and the four main surfaces 10a to 10d. Incidentally,
if the first and third intersecting points 118a and 118c are displaced
relative to each other in the direction of the axis of the distal
end portion 3 that portion of the distal end portion 3 lying between
the intersecting points 18a and 18c has a square cross-section.
The present invention is not limited to the above embodiments,
and various modifications can be made. For example, the major body
portion of the bar may not be flattened, but may have a circular
cross-section. The angle of intersection between the first and second
main surfaces, as well as the angle of intersection between the
third and fourth main surfaces, may be about 60.degree.. The proximal
end portion of the suture needle may be pressed into a flattened
shape, and a gut-attaching hole may be formed in this flattened
proximal end portion so as to extend perpendicular to the axis thereof.
As shown in FIG. 27 the main grinding may be carried out to form
a distal end portion 203 into a parallelogrammatic shape, so that
the width of first and third main surfaces 210a and 210c is smaller
than the width of second and fourth main surfaces 210b and 210d.
In this case, also, a pair of cutting edges 211a and 211c as well
as a pair of obtuse edges 211b and 211d are formed. |