Anvil and driver assembly for a surgical skin stapling instrument

An anvil and driver assembly for a surgical skin stapling instrument producing formed and implanted skin staples of more consistant and perfect configuration. The anvil provides an anvil surface which supports the crown of the staple during the forming operation. The driver has an inverted U-shaped notch formed therein which defines parallel side edges to bend the staple legs about the anvil and a transverse edge joining the side edges and adapted to contact the crown of the staple near the end of the forming operation. In the anvil and driver assembly of the present invention, the clearance between the parallel bending edges of the driver and the adjacent anvil edges is greater than the transverse dimension of the staple wire. The anvil surface of the anvil is concave and the crown contacting edge of the driver is so configured as to impart a temporary bow in the staple crown near the bottom of the driver stroke, which bow is of such dimension as to preclude plastic deformation of the crown. This produces a more generous bend and a slight over-bend at the junctures of the staple legs and the crown such that when the crown is released by the driver and returns to its rectilinear state, this action of the crown will compensate for the natural spring-back properties of the material from which the staple is made at the above noted junctures, consistantly producing the desired final formed configuration of the staple.

TECHNICAL FIELD 
The invention relates to an improved anvil and driver assembly for a 
surgical skin stapling instrument and more particularly to an anvil and 
driver assembly so configured as to impart a concave bow, within the 
elastic limit, to the crown of the staple during the forming operation to 
slightly overbend the junctures of the staple legs and the staple crown 
such that when the crown is released by the driver and elastic spring back 
returns it to its rectilinear state, the bends at the aforementioned 
juncture are as desired. 
BACKGROUND ART 
In recent years surgeons have come more and more to the use of surgical 
staples (sometimes referred to as staple sutures), rather than 
conventional thread sutures, for the closing of wounds or incisions in the 
skin of a patient. This is true in part because the use of surgical 
staples is a far easier procedure. Of even greater importance, however, is 
the fact that the use of surgical staples is very much faster. Thus, the 
time required for suturing can be substantially reduced, thereby reducing 
the length of time the patient must be maintained under anesthesia. 
Prior art workers have developed various types of surgical skin staplers. 
U.S. Pat. No. 3,873,016 teaches a pliers-like surgical stapler exemplary 
of those wherein the driver engages the forewardmost staple of a row 
thereof in a magazine and shifts the staple to an anvil and thereafter 
forms the staple about the anvil. U.S. Pat. Nos. 4,109,844 and 4,178,057 
teach surgical stapling instruments of the type provided with an anvil 
plate having a coextensive, forwardly extending anvil provided with an 
anvil surface. A row of staples is mounted on the anvil plate and means 
are provided to constantly urge the row of staples forwardly so that the 
forwardmost staple of the row is located on the anvil plate. The driver 
thereafter is used to form the forwardmost staple about the anvil, but no 
part of the force required of the surgeon is used to shift a staple to the 
anvil. U.S. Pat. No. 4,411,376 teaches an improved form of anvil plate 
having forward extensions such that the legs of all of the staples on the 
anvil plate and anvil are supported except the forwardmost staple in 
position to be formed and implanted. U.S. Pat. No. 4,485,953 describes a 
surgical stapling instrument adapted to extract a staple from a separate 
cartridge thereof and to thereafter form and implant the staple in the 
skin of the patient. 
The above description of surgical skin stapler types is representative 
only, and is not intended to be exhaustive. Most surgical skin staplers, 
however, are characterized by similar anvil-driver assemblies in that, 
during the forming and implanting operation, the anvil is located directly 
above the wound or incision. The anvil is characterized by a flat anvil 
surface located substantially parallel to the skin surface of the patient. 
The anvil surface supports the crown portion of the staple to be formed 
and implanted. 
The typical driver of prior art anvil and driver assemblies has an inverted 
U-shaped notch formed therein. The U-shaped notch defines parallel bending 
surfaces adapted to bend the staple legs about the anvil and at the same 
time implant the staple legs in the skin of a patient. The upper end of 
the driver notch provides a transverse surface substantially perpendicular 
to the parallel bending surfaces and extending therebetween. This 
transverse surface comprises a staple crown-contacting surface which 
engages the staple crown at the bottom of the driver stroke. The space 
between the edges of the anvil and the parallel bending surfaces of the 
driver are such as to tightly accommodate the staple legs. This is true so 
that the sharpest possible bend is achieved at the juncture between the 
staple legs and the crown. 
The above described interaction between the anvil and the driver has 
certain drawbacks. For example, the bends produced during the forming 
procedure at the junctures of the staple legs and the crown are severe and 
constitute substantially a coining operation. In addition, when the driver 
returns to its retracted position, the surgical staple has a tendency to 
be dragged with it. Furthermore, there sometimes is difficulty in slipping 
the anvil out from under the fully formed and implanted staple. A strong 
return spring must be used to return the driver to its normal retracted 
position, since at the completion of the forming and implanting step the 
staple legs are wedged between the parallel bending surfaces of the driver 
and the edges of the anvil. Finally, due to natural elastic springback of 
the wire from which the surgical staple is made, the staple legs tend to 
separate slightly after release from the driver and anvil so that an 
absolutely perfectly formed staple is difficult to achieve. 
At the present time, the majority of surgical staples are made from 
metallic wire. Not all surgical staples are made of metallic wire, 
however. For example, some surgical staples are made of materials which 
will dissolve in the body environment over a period of time. The present 
invention will be described in terms of the use of metallic wire staples, 
but it is to be understood that the invention is applicable to the use of 
surgical staples made of any appropriate, resilient, permanently 
deformable material. 
The present invention is based upon the discovery that if the anvil surface 
of the anvil and the staple crown contacting surface of the driver are so 
configured as to impart a slight concave bow to the crown portion of the 
staple during the forming and implanting procedure, and if the bow is of 
such size as to be within the elastic limit of the material from which the 
staple is made so that the staple crown is not plastically deformed, the 
junctures of the legs and crown can be slightly overbent so that when the 
staple crown is released by the driver, it can return to its rectilinear 
configuration and perfect square bends can be achieved at the junctures of 
the legs and the crown, producing consistently perfectly formed and 
implanted staples. In other words, the natural springback of the material 
from which the staple is made tends to bring the staple into perfect 
configuration, rather than to spread the staple legs away from a perfect 
configuration. Additional benefits are also derived from the present 
invention. For example, greater tolerance can be permitted between the 
parallel bending surfaces of the driver and the adjacent edges of the 
anvil. The staple does not have a tendency to be dragged with the driver 
as the driver is shifted to its normal retracted position and the anvil is 
more easily slipped from beneath the crown after forming and implanting. 
Less force is required to form the staple since more generous bends are 
formed at the juncture of the legs and the staple crown. Since the staple 
is not wedged between the parallel bending surfaces of the driver and the 
adjacent edges of the anvil, a return spring having a lesser force can be 
used to return the driver to its normal retracted position. The teachings 
of the present invention can be applied to any of the above described 
types of surgical stapling instruments. 
It is known to provide non-surgical staple with a crown portion having a 
permanent concave bow therein. This is taught, for example, in U.S. Pat. 
No. 2,351,608. This permanent concave crown bow is provided so that when 
the staple is driven into a relatively hard workpiece such as wood by a 
hammer, the hammer blows are applied to the staple at two points 
substantially in line with the axes of the staple legs. This minimizes 
bending of the staple legs during the driving operation. The concave shape 
of the staple crown is permanent and bears no relationship to a forming 
operation. 
U.S. Pat. No. 2,687,061 teaches the use of staples having permanent concave 
crown portions in a substantially conventional desk-top stapler. The 
concave crown portion of the staples cooperates with the staple pusher in 
the magazine in such a way as to reduce the likelihood of staples jamming 
in the magazine. Again, the concave crown of this reference has nothing to 
do with staple forming. 
DISCLOSURE OF THE INVENTION 
According to the invention there is provided an improved anvil and driver 
assembly for a surgical skin stapling instrument. The anvil provides an 
anvil surface which supports the crown of the staple during the forming 
operation. The driver has an inverted U-shaped notch formed therein which 
defines parallel side surfaces to bend the staple legs about the anvil and 
a transverse surface joining the side surfaces and adapted to contact the 
crown of the staple during the forming operation. 
According to the present invention, the anvil surface is concave and the 
crown contacting surface of the driver is correspondingly convex so as to 
impart a concave bow to the surgical staple crown during the driver stroke 
of the forming and implanting procedure. The bow is of such magnitude as 
to be within the elastic limit of the wire or other material from which 
the staple is made so that the staple crown is not plastically deformed. 
The bow assures that the staple is slightly overbent at the junctures of 
the staple legs and the crown. At the same time, the clearance between the 
parallel bending surfaces of the driver and the adjacent anvil edges is 
slightly greater than the transverse dimension of the wire from which the 
staple is made so that the bends at the junctures of the staple legs and 
the crown are more gentle bends than achieved by prior art structures, and 
require less bending force. As a result of the configuration of the anvil 
surface and the crown contacting surface of the driver, when the crown is 
released by the driver and springs back to its rectilinear state, the bend 
at the junctures of the legs of the staple crown will be more nearly 
square and the staple will be consistently formed into a more nearly 
perfect configuration.

DETAILED DESCRIPTION OF THE INYENTION 
As indicated above, the teachings of the present invention are applicable 
to a number of different kinds of surgical skin stapling instruments. For 
purposes of an exemplary showing only, the present invention will 
initially be described in its application to a surgical skin stapling 
instrument of the type taught in U.S. Pat. No. 4,411,378. Such a surgical 
skin stapling instrument is shown in cross section in FIG. 1. 
FIG. 1 illustrates a disposable surgical stapling instrument for forming 
and implanting surgical staples in the skin of a patient. The surgical 
skin stapling instrument is generally indicated at 1 and comprises a body 
2 having a rearward handle portion 3, a forward portion 4 and a magazine 
portion 5 located beneath the forward portion 4. A staple driver 6 is 
slidably mounted in the forward portion 4 of the instrument body 2. The 
staple driver 6 is shiftable between a first retracted or normal position 
(as shown) and a second extended or staple forming and implanting 
position. A trigger 7 is pivotally mounted within the body 2 as at 8. A 
portion of the trigger 7 is exposed beneath the body handle portion 3 for 
actuation by a surgeon. The forward end of the trigger 7 has a nose 
portion 9 in direct engagement with staple driver 6. The arrangement is 
such that when the exposed portion of trigger 7 is squeezed and caused to 
pivot into handle portion 3 of the body 2, the nose portion 9 of trigger 7 
shifts the staple driver 6 from its first retracted position to its second 
extended position. A leaf spring 10 is located within the body 2 
(primarily in the handle portion 3 thereof) above the trigger 7 to urge 
the trigger 7 to its normal unactuated position (as shown) and the staple 
driver to its normal or first retracted position. 
The magazine portion 5 of the body 2 houses an anvil plate 11. The anvil 
plate 11 terminates at its forward end in a coextensive anvil 12 located 
beneath the driver 6. A row of surgical staples 13 is mounted on anvil 
plate 11 and is slidable therealong. 
The magazine portion 5 of the instrument body 2 also houses a surgical 
staple feeder assembly. The feeder assembly comprises a feeder shoe 14 
slidably mounted on the anvil plate 11 behind the row 13 of surgical 
staples and a simple compression spring 15 which constantly urges the 
feeder shoe against the row of staples and constantly urges the row of 
staples along the anvil plate 11 to place a forwardmost staple of the row 
on the anvil 12 to be formed by staple driver 6. 
In operation, it is only necessary for the surgeon to locate the nose 16 of 
the instrument at the wound or incision site and thereafter squeeze 
trigger 7. The forwardmost staple of the row 13 will be formed and 
implanted in the patient's skin by driver 6. Upon release of trigger 7, 
the trigger 7 and driver 6 will return to their normal positions, 
permitting the next forwardmost staple of row to be located on anvil 12 by 
feeder shoe 14 and compression spring 15. At this point, the surgical 
stapling instrument 1 is again ready for use. 
The anvil plate 11 of the instrument of FIG. 1 is most clearly illustrated 
in FIG. 2. The anvil plate 11 is preferably formed of an appropriate metal 
for use in a surgical environment, such as stainless steel or the like. 
The anvil plate 11 has a longitudinally extending raised central portion 
17. At its forwardmost end, the raised central portion 17 terminates in 
anvil 12 which constitutes an integral one-piece part of the raised 
portion 17. The upper surface of anvil 12 constitutes anvil surface 18, 
which is coextensive with the upper surface of raised central portion 17. 
The raised central portion 17 of anvil plate 11 has lateral edges which 
terminate in downwardly depending portions, one of which is shown at 19. 
The portion 19 and its equivalent portion on the other side of the anvil 
plate (not shown) terminate in laterally extending flanges 20 and 21. The 
laterally extending flanges 20 and 21 may be provided with forward 
extensions 22 and 23, respectively, the purpose of which will be apparent 
hereinafter. 
Reference is made to FIG. 3 wherein a typical surgical staple, prior to 
forming and implanting, is generally indicated at 24. While not required, 
it is usual that the surgical staple 24 be made of wire of circular cross 
section. As is evident from FIG. 3, the staple in its initial, unformed 
condition comprises an elongated rectilinear portion terminating in 
downturned ends. That part of the elongated rectilinear portion supported 
by anvil surface 18 of anvil 12 comprises the crown 25 of the staple. That 
part of the rectilinear portion to the left of crown 25 constitutes a leg 
portion 26. The leg portion 26 terminates in a downturned leg portion 27 
which, in turn, terminates in a sharp point or tip 28. Similarly, that 
portion of the rectilinear part of the unformed staple to the right of 
crown 25 (as viewed in FIG. 3) constitutes leg portion 29. Leg portion 29 
terminates in downturned leg portion 30 which, itself, terminates in a 
point or tip 31. 
As is evident in FIG. 1, the unformed staples are arranged in a tandem row 
straddling the upper raised portion 17 of anvil plate 11. The tips of the 
staples are supported by lateral flanges 20 and 21. The lateral flange 
extensions 22 and 23 assure that all of the staple legs are supported, 
except for those of the forwardmost staple of row 13, as is clearly shown 
in FIG. 1. 
FIG. 3 also illustrates, in fragmentary form, the driver 6 of FIG. 1. The 
driver 6, at its lower end, has an inverted U-shaped notch (generally 
indicated at 32), formed therein. The U-shaped notch 32 defines a pair of 
vertical side edges 33 and 34 and a joining horizontal edge 35. The 
horizontal edge 35 may be interrupted by an additional notch, generally 
indicated at 36. The notch 36 may accommodate an element in the form of a 
lug or spring finger 37 mounted on the inside surface of the forward 
portion 4 of instrument body 2. The purpose of lug or spring finger 37 
will be described hereinafter. 
To complete the structure of driver 6, it will be noted that adjacent the 
vertical edges 33 and 34, the driver is provided with horizontal edges 38 
and 39, respectively. At the juncture of vertical edge 33 and horizontal 
edge 38 there is a gently curved edge 40. Similarly, at the juncture of 
vertical edge 34 and horizontal edge 39 there is a gently curved edge 41. 
FIG. 3 illustrates driver 6 at that point in its downward stroke (from its 
normal retracted position to its extended forming position) wherein it 
first contacts surgical staple 24. It will be noted that the lower 
horizontal edges 38 and 39 first contact leg portions 26 and 29 of staple 
24 beyond the side edges of anvil 12. It will be apparent that as the 
driver 6 shifts further downwardly, leg portions 26 and 29 will begin to 
bend at the edges of anvil 12 (i.e. at their juncture with the crown 
portion 25 of staple 24). As leg portions 26 and 29 shift downwardly and 
inwardly toward each other, they will be contacted by the gentle curved 
edges 40 and 41 of driver 6, and ultimately by vertical edges 33 and 34 
thereof. 
FIG. 4 illustrates the driver near its extendedmost position. It will be 
noted that lug or spring finger 37 limits the amount of upward bowing of 
staple crown portion 25 during the bending operation. When the driver has 
reached its extendedmost position, its horizontal joining edge 35 will 
press staple crown portion 24 against anvil surface 18. It will further be 
noted from FIG. 4 that the clearances provided between the edges of anvil 
12 and the vertical driver edges 33 and 34 are just sufficient to tightly 
engage staple leg portions 26 and 29 therebetween, in an attempt to 
achieve the squarest bends possible at the junctures of staple leg 
portions 26 and 29 and staple crown portion 25. When the staple is 
perfectly formed, the staple assumes a rectangular configuration with the 
leg points 28 and 31 aligned and substantially contiguous. 
At the end of the forming operation, the driver will reverse its direction 
of travel and shift upwardly (as viewed in FIGS. 3 and 4) to its normal, 
retracted position (shown in FIG. 1) under the influence of leaf spring 
10. Due to friction between the formed staple legs and the vertical driver 
edges 33 and 34, there is a tendency of staple 24 to drag upwardly with 
the driver. The amount by which the staple can shift upwardly with the 
driver is limited by the lug or spring finger 37. Once the driver 6 has 
attained its normal, retracted position, it is necessary to shift the skin 
stapling instrument 1 rearwardly of the staple to disengage anvil 12 
therefrom. This is sometimes difficult because the staple is tightly 
formed about anvil 12. 
Once the staple is free of driver 6, the natural spring back tendency of 
the wire or other material from which staple 24 is made tends to cause the 
staple leg tips 28 and 31 to separate slightly so that they are no longer 
in alignment and no longer nearly contiguous (see FIG. 5A). Leg portions 
26 and 29 are no longer substantially parallel and leg portions 27 and 30 
are no longer substantially coaxial. Thus, the desired perfect shape of 
the formed staple is very difficult to achieve. The bends at the junctures 
of leg portions 26 and 29 and crown portion 25 are severe and constitute 
substantially a coining operation, as is indicated in exaggerated form in 
FIG. 5A at 42 and 43, and in FIG. 5B at 43. 
The general configuration of the driver 6 and the anvil 12, as shown in 
FIGS. 3 and 4, is typical of the configurations found in most prior art 
surgical skin stapling instruments. The fully formed staple of FIG. 5A, in 
slightly less than perfect shape, is again typical of the formed staples 
of most prior art instruments. 
FIGS. 6 and 7 illustrate an anvil plate according to the present invention. 
The anvil plate is similar to that of FIG. 12, and like parts have been 
given like index numerals. The only difference between anvil plate 11 of 
FIG. 6 and anvil plate 11 of FIG. 2 lies in the coextensive anvil 12a and 
its anvil surface 18a. As can be most clearly seen in FIG. 7, the anvil 
surface 18a is concave. 
In FIG. 8, a driver 44a is illustrated, for use with the anvil plate 11 and 
its anvil surface 18a. The driver 44a has a notch, generally indicated at 
45a, formed in its lower end, as viewed in FIG. 8. The notch 45a provides 
a pair of parallel leg bending edges 46 and 47, equivalent to the leg 
bending edges 33 and 34 of driver 6 of FIG. 3. The upper ends of leg 
bending edges 46 and 47 are joined by a transverse crown contacting edge 
48a, equivalent to the crown contacting edge 35 of FIG. 3. The driver 44a 
is also provided with substantially horizontal edges 49 and 50, equivalent 
to horizontal edges 38 and 39 of FIG. 3. Between the vertical edge 46 and 
the horizontal edge 49 there is a rounded edge 51. Similarly, between the 
vertical edge 47 and the horizontal edge 50, there is a rounded edge 52. 
The rounded edges 51 and 52 are equivalent to the rounded edges 40 and 41 
of FIG. 3. Finally, if the instrument in which the driver 44a is to be 
used is provided with a lug or spring finger equivalent to lug or spring 
finger 37 of FIGS. 3 and 4, the upper crown engaging edge can be 
additionally notched as at 53. Additional notch 53 serves the same purpose 
as the additional notch 36 of FIG. 3. It will be noted from FIG. 8 that 
the crown contacting edge 48a is convex and is arcuate in configuration 
and substantially corresponds to the arcuate concave anvil surface 18a. 
This is the only real difference between the driver 44a of FIG. 8 and the 
driver 6 of FIG. 3. 
FIGS. 9, 10 and 11 illustrate the manner in which driver 44a of FIG. 3 and 
anvil surface 18a of FIG. 7 cooperate. FIG. 9 is similar to FIG. 3 and 
shows a forwardmost staple mounted and supported by anvil surface 18a. The 
surgical staple illustrated in FIG. 9 is identical to the staple 
illustrated in FIG. 3, and like parts have been given like index numerals. 
In FIG. 9, the driver 44a has shifted from its normal retracted position 
toward its forming position and is shown at its position of first contact 
with staple 24. It will be evident from FIG. 9 that the horizontal edges 
49 and 50 first engage staple leg portions 26 and 29. As is apparent from 
a comparison of FIGS. 9 and 10, further downward progress of driver 44a 
will cause the leg portions 26 and 29 to thereafter be contacted by 
rounded driver edges 51 and 52, followed by vertical leg bending edges 46 
and 47. FIG. 10 illustrates the driver 44a at the bottom of its stroke. 
Several things are to be noted in FIG. 10. First of all, the convex 
crown-contacting surface 48a of driver 44 has caused the crown 25 to 
conform to the concave bow of anvil surface 18a. The concave bow in crown 
25 has, however, not exceeded the elastic limit of the wire from which 
staple 24 is made and therefore, crown 25 has not been plastically 
deformed. It will be noted that the bends at the juncture of crown 25 and 
leg portions 26 and 29 are more generous and that the clearances between 
the edges of anvil 12 and the adjacent vertical leg bending driver edges 
46 and 47 is slightly greater than the transverse dimension of the staple 
wire. Finally, it will be noted that the staple points 28 and 31 are 
aligned and substantially contiguous. 
When driver 44a is withdrawn to its normal retracted position, the bends at 
the junctures of leg portions 26 and 29 and crown portion 25 tend to open 
slightly due to natural spring-back. At the same time, however, crown 25 
of staple 24 will return to its rectilinear condition. This is true 
because, as indicated above, the bow formed in the crown when the driver 
is at the bottom of its stroke does not create plastic deformation of the 
crown. When the crown 25 returns to its rectilinear condition, the points 
28 and 31 of the legs maintain an aligned, nearly contiguous position. 
Return of crown 25 to its rectilinear condition compensates for the 
natural spring-back at the bends at the junctures of crown 25 and leg 
portions 26 and 29. FIG. 11 illustrates the staple once driver 44a has 
been retracted and the anvil 12a has been withdrawn therefrom. FIG. 11 
shows a substantially perfectly formed surgical staple, a result 
consistently achieved with the structures of FIGS. 6-10. 
Since the bow imparted to crown 25 in FIG. 10 does not exceed the elastic 
limit, so that plastic deformation of the crown does not take place, the 
natural spring-back tendency of the staple wire brings the staple into a 
more nearly perfect form, rather than away from a perfect form, as in the 
case of prior art instruments as illustrated in FIGS. 3-5B. With more 
generous bends formed at the junctures of leg portions 26 and 29 and crown 
25, less force is required by the surgeon to form the staple. With greater 
clearance between the vertical leg bending driver surfaces 46 and 47 and 
the adjacent edges of anvil 12a, and with return of the staple crown 25 to 
its initial rectilinear state, there is less tendency for the staple to be 
dragged upwardly upon withdrawal of driver 44. As a result, a return 
spring 10 (see FIG. 1) of less force is required. Finally, as the crown 
portion 25 returns from its bowed state to its rectilinear state, it will 
elongate slightly, making withdrawal of the anvil 12a from beneath the 
crown 25 easier. The more generous bending of the staple at the juncture 
of its leg portions 26 and 29 and the crown 25 is not of the nature of a 
coining operation. 
As used herein and in the claims, the term "concave" as applied to the 
anvil surface is not limited to an arcuate concavity. Any appropriate, 
depressed center configuration can be used. FIG. 12, for example, is a 
cross sectional view similar to FIG. 7. In FIG. 12, the anvil 12b has a 
concave anvil surface 18b having a V-shaped configuration. 
FIG. 13 is a fragmentary elevational view of a driver 44b to be used with 
the anvil 12b. FIG. 13 is similar to FIG. 8, and like parts have been 
given like index numerals. The only difference between the driver 44b of 
FIG. 13 and the driver 44a of FIG. 8 lies in the fact that the convex 
crown-contacting edge 48b of FIG. 13 has a convex V-shape corresponding to 
the anvil surface 18b of FIG. 12. Thus the term "convex", as used herein 
in association with the driver, is not limited to arcuate convexity. The 
crown-contacting edge 48b may be provided with an additional notch (not 
shown) equivalent to the notch 53 of FIG. 8, if desired. 
FIG. 14 is a cross sectional view similar to FIG. 7 and shows an anvil 12c 
having a concave anvil surface 18c which is faceted, having a rectilinear 
depressed central surface flanked by upwardly and outwardly sloping 
lateral surfaces. Thus, the concave anvil surface may be made up of a 
number of adjacent surfaces. 
FIG. 15 is similar to FIG. 8 and illustrates a driver 44c to be used with 
the anvil 12c of FIG. 14. Again, like parts have been given like index 
numerals. In this instance, the crown-engaging convex edge 48c comprises a 
central rectilinear surface flanked by a pair of arcuate surfaces. Again, 
the central recilinear surface can be interrupted by an additional notch 
(not shown) similar to the notch 53 of FIG. 8, if desired. FIGS. 14 and 15 
illustrate the fact that the shape of the crown-contacting edge of the 
driver need not match the shape of the anvil surface. 
The combination of anvil 12b and driver 44b and the combination of anvil 
12c and driver 44c operate in substantially the same manner described with 
respect to FIGS. 9 and 10 and demonstrate the same results and advantages. 
FIGS. 16 and 17 illustrate another form an anvil. FIG. 17 is an elevational 
view of the rearward side of an anvil plate 53, normally mounted at the 
forward end of a surgical stapling instrument. The anvil plate has a 
rearwardly extending anvil 54 providing an anvil surface 55. As is most 
clearly seen in FIG. 16, a driver 56 is mounted adjacent the rearward face 
of anvil plate 53. The driver 56 is capable of being shifted from its 
normal retracted position shown in FIG. 16 toward anvil 54 to a staple 
forming position. A row of staples 57 is mounted on a staple guide 58. 
Means (not shown) are provided to constantly urge the row of staples 57 
toward anvil plate 53. The forwardmost staple of the row is maintained off 
the forward end of staple guide 58 between the row of staples 57 and the 
rearward surface of anvil plate 53. When the driver 56 is shifted 
downwardly (as seen in FIG. 16), it strips the forwardmost staple from the 
row and shifts the forwardmost staple downwardly to anvil surface 55, 
about which the staple is formed by the driver 56. Once the staple has 
been formed and the driver retracted, the instrument is moved slightly 
forward to disengage the anvil 54 from beneath the staple crown. 
It will be apparent from FIG. 17 that anvil 54 is similar to anvil 12a of 
FIG. 7, having an anvil surface 55 identical to anvil surface 18a of FIG. 
7. The driver 56 will be provided with a notch (not shown) configured 
substantially identically to the notch 45a in driver 44a of FIG. 8. As a 
result, the forming step of the structure of FIG. 16 will be substantially 
identical to that described with respect to FIGS. 9-11. 
FIG. 18 illustrates an anvil plate 59 similar to anvil plate 53 of FIG. 17. 
In this instance, however, anvil plate 59 has an anvil 60 with an anvil 
surface 61 similar to anvil 12b and anvil surface 18b of FIG. 12. The 
anvil plate 59 will be used with a driver having a notch and crown 
contacting edge substantially identical to notch 45b and crown contacting 
edge 48b of FIG. 13. 
FIG. 19 illustrates an anvil plate 62 having an anvil 63 with an anvil 
surface 64. The anvil 63 and anvil surface 64 are similar to anvil 12c and 
anvil surface 18c of FIG. 14. Anvil plate 62 would be used with a driver 
having a notch and crown contacting edge equivalent to the notch 45c and 
crown contacting edge 48c of driver 44c of FIG. 15. It will be understood 
that the operation of anvil plate 59 of FIG. 18 and anvil plate 62 of FIG. 
19, together with their respective drivers, will be otherwise 
substantially similar to that described with respect to FIGS. 9-11. 
FIGS. 20 and 21 illustrate the teachings of the present invention applied 
to a surgical stapling instrument of the type taught in U.S. Pat. No. 
3,873,016. 
U.S. Pat. No. 3,873,016 teaches a pliers-like surgical stapling instrument, 
the lower jaw of which is illustrated in FIGS. 20 and 21. The lower jaw 65 
supports a staple feed housing 66 in which a row of staples 67 is slidably 
mounted. The row of staples is constantly urged forwardly by a pusher head 
68, and a compression spring 69. 
To the forward end of lower jaw 65 and staple feed housing 66 there is 
affixed a vertical staple guide, generally indicated at 70. The staple 
guide comprises a front plate 71 and a rear plate 72 forming a slideway 73 
therebetween. A ram or driver 74 is mounted in the slideway 73 and is 
operatively connected to the upper jaw (not shown) of the instrument. 
Thus, when the upper and lower instrument jaws are shifted from an open to 
a closed position, the ram or driver 74 will shift downwardly to a staple 
forming position, from a normal retracted position. The pusher head 68 and 
compression spring 69 constantly urge the row of staples 67 forwardly, so 
that the forwardmost staple of the row passes through an opening in rear 
plate 72 and is located in slideway 73. 
An angle plate 75 is affixed to the staple feed housing 66 and provides at 
the lower end of the slideway 73 an anvil 76 having an anvil surface 76a. 
When the ram or driver 74 is shifted downwardly by the closing of the 
instrument jaws, the driver will shift the forwardmost staple in slideway 
73 downwardly until its crown engages anvil surface 76a. Further downward 
movement of driver 74 will form the staple about anvil 76. 
To achieve the benefits of the teachings of the present invention in the 
operation of the surgical stapling instrument of U.S. Pat. No. 3,873,016, 
it is only necessary to provide the anvil 76 with an anvil surface 76 a 
having a concave configuration similar to anvil surface 18a of FIG. 7. 
This is shown in FIG. 21. Under these circumstances, the driver 74 will be 
provided at its lower end with a notch and crown contacting edge 
equivalent to notch 45a and crown contacting edge 48a of FIG. 8. The 
operation of the thus modified anvil 76 and driver 74 will be the same as 
described with respect to FIGS. 9-11. 
It will be understood that it would be within the scope of the invention to 
configure the anvil surface 76a of FIG. 21 after the manner of anvil 
surface 18b of FIG. 12 or anvil surface 18c of FIG. 14. Under these 
circumstances, the driver would be provided with a notch and crown 
contacting edge at its lower end configured like notch 45b and crown 
contacting edge 48b of FIG. 13 or notch 45c and crown contacting edge 48c 
of FIG. 15, respectively. 
The same sort of modification could be made to other types of skin 
staplers, such as that taught in U.S. Pat. No. 4,485,953. U.S. Pat. No. 
4,485,953 describes a pliers-like surgical stapling instrument for use 
with a wholly separate one-piece cartridge containing a plurality of 
staples. Each staple is individually withdrawn from the cartridge by the 
surgical stapling instrument, to be implanted and formed in the skin of a 
patient. This surgical stapling instrument is illustrated in FIG. 22 and 
is generally indicated at 77. The surgical stapling instrument comprises a 
first or upper handle 78, a second or lower handle 79, a pivot pin and 
keeper assembly 80, a former 81, an upper spring 82 affixed to the upper 
handle 78 and a lower spring 83 affixed to the lower handle 79. The upper 
handle 78 has at its forward end a central body portion 84 terminating in 
an elongated downwardly depending nose portion 85. The central body 
portion 84 has a slot (not shown) formed therein. The forward end of lower 
handle 79 is located in this slot and is pivotally affixed therein by the 
pivot pin and keeper assembly 80. 
The elongated nose portion 85 provides a flat forward face 86. Near its 
lower end the nose portion 85 is provided with a forwardly extending lug 
of T-shaped cross section, the shank portion of which is shown at 87 in 
FIG. 23. The nose portion 85 terminates in a forwardly extending anvil 87 
having an anvil surface 88. The forwardly extending anvil 87 also has a 
downwardly depending flange or keel 89 which cooperates with the separate 
cartridge to properly align the bottom end of the nose portion 85 within 
the cartridge during pickup and removal therefrom of a surgical staple. 
The former 81 of the surgical stapling instrument comprises an elongated 
member having a flat rear surface adapted to cooperate with the flat 
forward surface 86 of nose portion 85. Near its upper end, the former 81 
has a slot or window (not shown) formed therethrough. The forwardmost end 
79a of lower handle 79 extends through this slot and thereby engages the 
former 81. Just below the slot, the rear surface 90 of the former 81 is 
provided with a rearwardly extending lug of T-shaped cross section. This 
lug is adapted to be slidably received in appropriately configured slot 
means in the central body portion 84. Similarly, the lug of T-shaped cross 
section on the forward face of nose portion 85 is adapted to be received 
in an appropriately configured slot in former 81, a portion of which is 
shown at 91 in FIG. 23. In this way, former 81 is slidably and captively 
mounted on the forward surface 86 of nose portion 85 and is shiftable 
through the agency of lower handle 79 between a retracted position 
illustrated in FIG. 22 and a staple forming position. 
In operation, the lower end of nose portion 85 including keel 89 is 
inserted in a longitudinal slot in the separate cartridge. The anvil 87 is 
located beneath the crown portion of a staple within the cartridge and the 
lower handle 79 is shifted toward the upper handle 78 until the staple 
crown in engaged between the anvil surface 88 and the lower end of former 
81. Means are provided at the rearward ends of springs 82 and 83 to lock 
the handles in this position so that the as yet unformed staple can be 
withdrawn from the cartridge and located over the wound or incision site. 
Further closure of lower handle 79 toward upper handle 78 releases the 
springs 82 and 83 and causes the staple to be formed in substantially the 
same manner described with respect to FIGS. 3, 4 and 5A above. Upon 
release of the lower handle 79, the springs 82 and 83 cause it to return 
to its normal, unactuated position, returning the former 81 to its 
retracted position. 
FIG. 23 illustrates the lower end of nose portion 85, the lower end of 
former 81, anvil 87 and keel 89 of the instrument of FIG. 22 with the 
anvil 87 and former 81 modified in accordance with the teachings of the 
present invention. To this end, the anvil surface 88a of anvil 87 is 
provided with a concave shape, as shown. Thus, the anvil surface 88a is 
similar to anvil surface 18a of FIGS. 7, 9 and 10. 
The lower end of former 81 is provided with a notch generally indicated at 
92. The notch 92 comprises a pair of parallel sides 93 and 94 joined by an 
arcuate, convex, staple crown-contacting surface 95. It will be noted that 
the parallel notch sides 93 and 94 terminate at their lower ends in gentle 
curves 96 and 97, which, in turn terminate in horizontal surfaces 98 and 
99. Thus, the former notch 92 is similar to the notch 45a illustrated in 
FIG. 8. In FIG. 23, a surgical staple 100 is illustrated in position on 
anvil surface 88a. It will be understood by one skilled in the art that 
the forming of staple 100 will be substantially identical to that 
described in detail with respect to FIGS. 9, 10 and 11 with all of the 
advantages achieved by the practice of the present invention. It will 
further be understood that anvil surface 88a and the crown engaging edge 
95 of the former could be configured as shown in FIGS. 12 and 13, 
respectively, or FIGS. 14 and 15, respectively. 
In the description of the present invention presented above, the ideal 
shape of a surgical staple is shown and described with respect to FIG. 11 
as being rectangular with leg portions 27 and 28 being substantially 
coaxial and leg tips 28 and 31 being substantially contiguous. At the 
present time, a surgical staple of this formed configuration is considered 
to be the industry standard. Should this standard change, or should other 
shapes be developed for specialized purposes, the teachings of the present 
invention can be employed to achieve controlled positioning and spacing of 
the leg tips and the particular desired angularity between leg portions 26 
and 29 and the crown 25 utilizing a low force, with consistent results and 
without coining. By appropriate configuration of the anvil surface and the 
driver or former and its crown contacting edge, the final desired 
configuration of the staple can be achieved with compensation for the 
natural spring back properties of the material from which the staple is 
made. 
It will be understood by one skilled in the art that words used herein such 
as "vertical", "horizontal", "upwardly", and "downwardly" are used in 
conjunction with the drawings for purposes of clarity. It will be 
appreciated that in use, a surgical stapling instrument can be held in any 
orientation required by the skin surface to which a staple is to be 
applied. 
Modifications may be made in the invention without departing from the 
spirit of it. For example, throughout the above description, the crown 
portion of the surgical staple has been described as being rectilinear 
before and after forming. While this is generally the case, it is not a 
requirement for the practice of this invention. As an example, staples 
have been devised having crown portions with a raised central part for 
easier engagement by an extractor. The teachings of the present invention 
are equally applicable to such staples.