Surgical needle abstract
A combined surgical needle-suture device is disclosed in which
the suture is received into a socket, or recess, formed within the
blunt end of the needle, the entrance to the socket being defined
by a circumferential sloping surface which terminates at its outer
end in a circumferential cutting edge which provides quick and convenient
suture cut-off capability when severing of the suture from the needle
is desired.
Surgical needle claims
What is claimed is:
1. In a combined surgical needle-suture which includes a surgical
needle having a sharp end and a blunt end with a suture-receiving
socket at said blunt end, a suture having one tip received within
said socket and means for retaining the tip of the suture within
the socket, the improvement which comprises a circumferential inwardly
sloping surface defining the entrance to the socket, said sloping
surface terminating at one end in the socket and at the other end
in a circumferential cutting edge separated a distance from the
suture, the slope of said being defined by an inclusive angle X
the value of which is from about 90.degree. to about 110.degree..
2. The surgical needle-suture combination of claim 1 wherein inclusive
angle X is from about 95.degree. to about 105.degree..
3. The surgical needle combination of claim 1 wherein the needle
is fabricated from stainless steel.
4. A method for separating the suture component from the surgical
needle component of a combined surgical needle-suture device wherein
a tip of the suture is retained within a socket formed within the
blunt end of the needle, said socket possessing a circumferential
sloped entrance, which comprises:
(a) orienting the suture relative to the needle such that the suture
is made to bear under a tensioning force against any location along
a circumferential cutting edge separated a distance from the suture
and formed upon the inwardly sloped entrance to the needle socket,
said sloped surface being defined by an inclusive angle X the value
of which is from about 90.degree. to about 110.degree..
5. The method of claim 4 wherein the applied tensioning force is
from about 3 ounces to about 4 pounds.
6. The method of claim 4 wherein the sloped surface of the socket
possesses an inclusive angle X of from about 95.degree. to about
105.degree..
7. The method of claim 6 wherein the applied tensioning of force
is from about 6 ounces to about 2.5 pounds.
Surgical needle description
CROSS REFERENCE TO RELATED APPLICATION
This application relates by subject matter to commonly assigned,
concurrently filed U.S. patent application entitled "Apparatus
For Forming a Suture Cut-Off Feature In A Surgical Needle Possessing
a Suture-Receiving Socket" [U.S. Ser. No. 317949].
BACKGROUND OF THE INVENTION
This invention relates to a combined surgical needle-suture device
possessing an integrated suture cut-off feature and to a method
for separating the needle from its attached suture.
The prior art describes a variety of arrangements for securing
a suture within an axial socket, or recess, provided at the blunt
end of a surgical needle and for providing release, or separation,
of the needle from the suture upon completion of suturing. Illustrative
of such suture-surgical needle combinations are those described
in U.S. Pat. Nos. 1757129; 3799169; 3910282; 3926194; 3943933;
3949756; 4054144; and, 4072041. Specific techniques provided
in these prior disclosures for achieving separation of the suture
from the needle include peeling the suture out of a channel formed
in the rear of the needle as shown in U.S. Pat. No. 3799169 and
tugging sharply at the needle within some predetermined range of
"pull-out" force to effect separation of the needle and
suture at the site of a weakened suture segment as shown in U.S.
Pat. Nos. 3926194; 3943933; 3949756; 4054144; and, 4072041.
U.S Pat. No. 2910983 describes a surgical needle-suture combination
in which the suture is held securely within a crimped socket possessing
an outer sharp circumferential edge. The sole disclosed function
of the sharp edge is to provide a flared entrance to the socket
thus preventing damage to the suture. There is no suggestion in
U.S. Pat. No. 2910983 of providing a sharp edge for the purpose
of achieving suture cut-off.
U.S. Pat. No. 86769 describes a needle-and-thread combination
for sewing canvas in which a forward section of the needle possesses
a cutting edge for cutting the attached thread when desired.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a surgical
needle-suture combination possessing a suture release feature.
It is a particular object of the invention to provide a socketed
surgical needle-suture combination which provides for separation
of the suture from the needle by a quick, sharp lateral movement
of the suture away from the needle.
It is a further particular object of the invention to provide a
socketed surgical needle-suture combination in which separation
of the suture from the needle at their junction is achieved by application
of a cutting movement to the suture while the suture is held under
tension upon any point along a circumferential cutting edge defined
upon the socketed end of the needle.
In keeping with these and other objects of the invention, in a
combined surgical needle-suture device which includes a surgical
needle having a sharp end and a blunt end with a suture-receiving
socket at said blunt end, a suture having one tip received within
said socket and means for retaining the tip of the suture within
the socket, an improvement is provided which comprises a circumferential
sloping surface defining the entrance to the socket, said sloping
surface terminating at one end in the socket and at the other end
in a circumferential cutting edge, the slope of said surface being
defined by an inclusive angle the minimum value of which is sufficient
to preserve an amount of strength in the needle material associated
with said cutting edge such that said needle material will resist
being torn away during cutting of the suture against the circumferential
cutting edge and the maximum value of which does not attain that
at which the circumferential edge of the entrance of the socket
is no longer effective as a cutting edge.
To effect separation of the needle from the suture, the suture
is oriented relative to the needle such that the suture is made
to bear against any location along the circumferential cutting edge
of the needle socket entrance and, while the suture is held in tension
against the cutting edge, an arc-like, or sweeping, movement of
the suture against the cutting edge is employed to effect separation
of the needle from the suture at their junction.
The suture cut-off feature of the combined surgical needle-suture
device of this invention provides a quick, simple, convenient and
effective means for achieving separation of the suture from the
needle at any point along the circumferential cutting edge of the
latter without the need for a separate cutting instrument. In general,
the amount of force required to effect separation of the suture
from the needle is significantly less than that required by known
and conventional needle-suture combinations which require that some
minimum "pull-out" force be applied to the suture against
the needle or that some force which is sufficient to break a weakened
suture segment be applied thereto.
Since the cutting movement required to effect separation of the
suture from the needle of this invention is a deliberate one and
is entirely distinct from any of the movements employed in suturing,
there is no possibility that in the absence of a deliberate intention
to sever the suture from the needle, there can be an accidental
separation of the one from the other. Accordingly, unlike known
and conventional surgical needle-suture combinations such as those
referred to above, the combined surgical needle-suture device of
this invention avoids any compromise in a firm attachment of the
suture to the needle and permits the surgeon to sever the suture
only by a deliberate, purposeful severing movement of the needle
held in tension against the needle's circumferential cutting edge.
BRIEF DESCRIPTION OF THE DRAWINGS
Figs. 1A and 1B are enlarged cross sectional views of the axial
suture-receiving socket end of the surgical needle component of
a surgical needle-suture combination in accordance with this invention
showing the side profile of the socketed end of the needle before
(FIG. 1A) and after (FIG. 1B) attachment of the tip of the suture
to the needle;
FIG. 2 illustrates the method of separating the suture from the
needle in the surgical needle-suture combination of this invention;
FIG. 3A is a perspective view of an axially movable cutting edge
forming tool for use in an apparatus for forming the cutting edge
in the surgical needle shown in FIGS. 1A-B and 2;
FIG. 3B is an exploded perspective view of the principal elements
of the aforesaid cutting edge forming apparatus;
FIG. 3C is an exploded side elevational view of the locking ram,
collet and collet holder elements of the apparatus of FIG. 3B; and,
FIG. 3D is a perspective view of the assembled apparatus of FIG.
3B.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The apparatus of the present invention and its operation will be
specifically described in connection with the manufacture of a preferred
type of surgical needle, i.e., the socketed needle possessing a
suture cut-off.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1A, the rear portion of surgical needle 10 possesses
a sloping surface 11 defining the entrance to a concentrically positioned
socket 12. Sloping surface 11 terminates in a circumferential cutting
edge 13 which possesses an inclusive angle x formed at the junction
of opposed sloped surfaces. The cutting edge can be smooth as shown
or it can be notched or serrated to enhance its cutting action.
In FIG. 1B, tip 14 of suture 15 is shown occupying socket 12 of
needle 10 and is held tightly within the socket by a crimping of
needle section 16 about the tip of the suture. Crimping has no appreciable
affect upon the value of inclusive angle X.
Aforesaid angle x which defines the slope of the socket entrance
is critical to achieving effective suture cut-off. On the one hand,
if the value for inclusive angle X is below a certain minimum (which
depends upon the structural/mechanical properties of the material
from which the needle is fabricated and can be readily determined
in a given case by simple and routine testing), the slope of the
socket entrance will be too steep for the needle material in the
vicinity of the socket entrance to withstand the force of the tensioned
cutting movement which is employed to sever the suture upon the
circumferential cutting edge. If, on the other hand, the value for
inclusive angle X exceeds a certain maximum (again, as in the case
of the minimum value of X, a variable which depends some extent
upon the nature of the material from which the needle is fabricated
and is readily determined for a specific needle construction by
simple, routine testing), the slope of the socket entrance will
be too shallow to provide an effective cutting edge. For surgical
needles manufactured from any of the stainless steels which are
commonly used for the construction of such needles, the value of
inclusive angle X is advantageously on the order of from about 90.degree.
to about 110.degree. and preferably is from about 95.degree. to
about 105.degree..
In addition to the values, supra, for inclusive angle X, other
suitable dimensions for various sizes of needle-suture devices in
accordance with this invention are set forth in the following table.
TABLE __________________________________________________________________________
Needle Dimensions Socket Suture Needle Diameter, Socket Size Suture
Diameter Diameter, thousands of an Depth, Designation mm inches
inches inch (mils) inches __________________________________________________________________________
6-0 0.070-0.099 0.0026-0.0039 0.013 6.4-7.0 0.030 5-0 0.10-0.149
0.0039-0.0059 0.015 8.8-9.6 0.035 4-0 0.15-0.199 0.0059-0.0078 0.017
10.2-11.0 0.042 0.022 3-0 0.20-0.249 0.0079-0.0098 0.024 12.5-13.5
0.050 0.039 2-0 0.030-0.399 0.0118-0.0133 0.026 15.2-16.2 0.057
0.039 0.050 1-0 0.35-0.399 0.0138-0.0157 0.039 18.2-19.2 0.060 0.044
0.050 1 0.40-0.499 0.0157-0.0196 0.039 21.2-22.2 0.070 0.044 0.050
__________________________________________________________________________
While the surgical needle-suture combination herein is in use,
suture 15 will ordinarily avoid contact with cutting edge 13 of
socket entrance 11. Occasional, unintentional and non-tensioned
contact of the suture with circumferential cutting edge 13 will
not affect the integrity of the surgical needle-suture combination.
However, upon completion of suturing when separation of the surgical
needle from the suture is desired, a deliberate arc-like, or sweeping,
movement applied to the tensioned suture generally in the direction
indicated by the arrow in FIG. 2 will be sufficient to sever the
suture against circumferential cutting edge 13. Depending upon the
size of the suture, an amount of force on the order of from about
3 oz. to about 4.0 lb., and preferably from about 6 oz. to about
2.5 lb., and one or just a few back-and-forth sweeps of the suture
against cutting edge will be effective to accomplish suture cut-off.
The surgical needle component herein can be fabricated from any
suitable material, e.g., any of the stainless steels heretofore
known or used for the construction of surgical needles. The needle
can possess any appropriate shape, e.g., it can be straight or it
can possess the largely curved configuration shown in FIG. 2.
Referring once again to Figs. 1A and 1B, circumferential sloping
socket entrance 11 socket 12 and circumferential cutting edge 13
of needle 10 can be formed employing known or conventional machining
techniques. However, it is particularly advantageous to form these
elements employing the suture cut-off needle manufacturing apparatus
of commonly assigned concurrently filed U.S. patent application
Ser. No. 317949 referred to above and illustrated in FIGS. 3A-D
herein.
As shown in the apparatus of FIG. 3A, drilling unit 20 is provided
as a fluted drill bit 21 held in spindle 22 of a high speed motor
23. Spindle 22 should be capable of holding drill 21 with considerable
accuracy, e.g., with a maximum positional variation of no more than
about 0.00015 inches. The drill together with its motor is supported
upon a linear bearing member 24 which permits movement of drill
21 toward and away from the rear face of a socketed needle, e.g.,
with a straight line accuracy of at least 0.0005 in./in. of travel,
as shown in FIG. 3D.
As shown in FIGS. 3B-D, needle receiving and holding collet 30
possesses a central bore 31 extending its full length for receiving
the socketed end of a surgical needle. The collet possesses three
slots 34a, 34b and 34c extending from its front face 33 to rear
face 32 along conical shaped wall 35. These slots enable the collet
to convert an axially directed force exerted against its rear face
32 to a circumferentially compressive force exerted against the
blunt end of a needle present within bore 31 whereby the needle
is held firmly and accurately in place within the collet for the
subsequent circumferential suture-cutting edge-forming operation
(as well as any optional socket forming operation). Collet holder
40 functions as a support frame for collet 30 and orients and guides
the axial movement of the collet upon activation of locking ram
50. Opening 41 in collet holder 40 possesses a conical configuration
providing an accurate mating support surface for collet 30 and permitting
a limited degree of forward, axial movement of the collet therein
when locking ram 50 is set in motion. Key 42 along the periphery
of opening 41 of collet holder 40 cooperates with slot 36 in the
collet to precisely orient the collet and make certain that the
socketed end of the needle held within the collet is accurately
positioned relative to drilling tool 21. Clearance slot 43 is provided
on the collet holder in order to fully accommodate a curved needle
during the machining thereof.
To accomplish locking of the needle within the collet and locking
of the collet within its holder, a vertical movement of locking
ram 50 against the upwardly sloping surface 37 of rear face 32 of
collet 30 causes an axial forward movement of the collet within
opening 41 of collet holder 40. Activation of locking ram 50 results
in the application of an amount of force against collet 30 which
is sufficient to slightly compress the sections of the collet as
defined by slots 34a, 34b and 34c thereby securely locking the needle
in place for drilling.
The geometries of those surfaces of collet 30 collet holder 40
and locking ram 50 which come into mutual contact during the locking
step are important to achieving effective and accurate locking.
Thus, the forward face 51 of locking ram 50 is so shaped as to present
a downwardly sloping angle, in the embodiment shown, 5.degree.
corresponding to the 5.degree. angle of upwardly sloping surface
37 formed on the rear face 32 of collet 30. As the driving ram moves
upwardly along a vertical axis which is perpendicular to the longitudinal
axis of the collet, the resulting engagement of mating surfaces
51 and 37 forces collet 30 forward within the collet holder, the
9.degree.30' slope of collet wall 35 engaging the 9.degree. sloping
wall 44 of collet holder 40. The slightly greater angle of wall
35 of collet 30 relative to that of wall 44 of collet holder opening
41 results in the application of a transversally directed spring-like
compressive force against collet 30 upon activation of locking ram
50 which firmly locks the needle in place.
When locking ram 50 is lowered, i.e., returned to the unlocked
position, release of the compressive force against collet 30 results
in rearward movement of the collet within collet holder 40 accompanied
by a rearward ejection of the needle, now possessing a circumferential
suture-cutting edge, from the collet bore.
In the embodiment shown, positional needle tolerance in the locked
condition of the apparatus is held to a maximum deviation from the
longitudinal axis of the needle of not more than about 0.00025.degree..
Thus, the apparatus of this invention makes it possible to obtain
very accurate positioning of the blunt end of the needle relative
to the drill and to maintain this position throughout the socket
and circumferential suture-cutting edge-forming operations. In the
enlargement of the tip of drill 21 shown in FIG. 3B, the included
angle formed by the sloping surfaces of the drill is established
so as to define the value of inclusive angle x of the slope of the
socket edge. In the embodiment shown, this angle is set at 100.degree..
During the cutting edge forming operation minute metal shavings
or particles may tend to lodge within the socket. Prior to inserting
the suture within the socket, it is preferred to remove these shavings
employing any effective technique, for example, an ultrasonic cleaning
operation.
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