Surgical stapling apparatus

An improved circular anastomosis surgical stapling instrument for joining hollow tubular organs, has a body having a staple-carrying assembly at its distal end, a centered longitudinally extensible and retractable main shaft centered in the body, and an anvil opposed to the staple-carrying assembly, and is characterized by a separate shaft segment frictionably connectible with the end of the main shaft, the shaft segment having a free end and an end carrying the anvil. The main shaft has a hollow free end and the free end of the shaft segment is releasably receivable in the hollow end of the main shaft. In a preferred form the end of the main shaft is provided with a plurality of several radially-extending arms positioned to overlie the main shaft but having spring hinges biasing them radially outwardly away from the main shaft. The instrument further includes a second shaft segment releasably receivable in the hollow of the main shaft which second shaft segment has a concial pointed unit at its distal end.

FIELD OF THE INVENTION 
This invention relates to a surgical stapling apparatus and is more 
particularly concerned with an improved circular anastomosis surgical 
stapler. 
BACKGROUND OF THE INVENTION 
There are several known types of surgical staplers in which the stapling 
function takes place at a location which is relatively remote from the 
location at which the stapler is held and actuated by the operator. 
Examples of such staplers are the circular anastomosis surgical staplers 
shown illustratively in Akhalaya et al, U.S. Pat. No. 3,193,165 and Noiles 
U.S. Pat. No. 4,351,466. Typically, instruments of the types exemplified 
by these references, include a main body which is provided with a 
staple-holding assembly at its distal end and a longitudinal connecting 
shaft which is axially movable within the body and extends outwardly from 
the distal end of the body. The anvil assembly is fixed or threaded onto 
the free end of the shaft so that, when the shaft is caused to reciprocate 
with respect to the body, the anvil assembly can be caused to move toward 
and away from the staple-holding assembly. When such an instrument is 
used, tissue to be stapled is fastened about the staple-holding assembly 
and about the anvil assembly and clamped between them. The clamped tissue 
is then stapled by driving a plurality of staples from the staple-holding 
assembly so that the ends of the staples pass through the tissue and are 
clinched by contact with the anvil assembly. The forces required to 
operate the instrument to eject the staples are applied by the operator of 
the instrument to one or more actuator elements located at or near the 
proximal end of the body of the instrument. Means are also provided for 
causing the shaft to advance and retract. These means are generally at the 
proximal end of the body of the instrument. Thus, the distal and proximal 
portions of the instrument are joined by the longitudinal connecting shaft 
structure along which the actuating forces and motions are transmitted to 
the distal operating elements. This type of construction, including 
relatively widely-spaced distal and proximal portions, is conventionally 
used. 
In a typical procedure, e.g. in colon surgery, the sections of the colon to 
be joined are, respectively, secured manually about the staple-holding 
assembly and the adjacent shaft portion and about the anvil of the 
instrument and the adjacent shaft portion. The head and anvil are then 
drawn together by causing the longitudinal connecting shaft to the end of 
which the anvil assembly is rigidly mounted to retract in the instrument 
body, so that the anvil assembly approaches the staple-holding assembly 
carried by the instrument body, and thereupon the stapling operation 
ensues. 
A serious problem with the procedure just described is that, when using 
surgical stapling devices of the prior art, the surgeon must work "blind" 
to some extent since the staple-holding assembly and the anvil assembly 
are each rigidly connected to the instrument at a limited distance from 
each other and he must apply the tissue in a limited space and, at times, 
he cannot fully view all parts of the tissue to be stapled. Vision is 
limited by the rigid relationship between the staple-carrying assembly and 
the anvil assembly so that the gap or distance between the two is often 
unduly confining. In addition, because the anvil blocks the surgeon's 
view, as frequently happens, if the purse-string sutures fixing the bowel 
around the instrument are loose or incomplete, after the instrument is 
fired and withdrawn, the anastomosis has to be redone. Even worse, 
occasionally, this is not recognized and a leak can occur, resulting in 
pelvic infection or worse. 
Currently, surgical stapling instruments are constructed so that they can 
be economically discarded after use in a single surgical procedure, i.e., 
so-called disposable instruments. Typically, a disposable instrument is 
sold in sterile condition in packaging designed to keep the instrument 
sterile until used. After the instrument has been used in a surgical 
procedure, it is discarded. In this way, all difficulty and expense 
associated with cleaning, sterilizing, and reloading the instrument are 
entirely avoided. 
For an instrument to be economically disposable after use in only one 
surgical procedure, however, the cost of the instrument must be relatively 
low. This generally dictates that as much as possible of the instrument be 
made of inexpensive materials such as plastics, and that the instrument 
have the simplest and lightest possible construction. These criteria for 
an economically disposable instrument require a non-complicated 
construction for the instrument. 
OBJECTS OF THE INVENTION 
In view of the foregoing, it is an object of this invention to provide an 
improved surgical stapler of the type having distal stapling elements and 
proximal actuating elements. 
It is another object of this invention to provide an improved surgical 
stapler of the character described which is economically disposable. 
It is a further object of this invention to provide an improved circular 
anastomosis surgical stapler. 
It is a still further object of this invention to provide an improved 
circular anastomosis surgical stapler which will give the surgeon 
increased freedom of action, as well as improved visibility, to ensure 
proper stapling and thus improved results and safety for patents. 
SUMMARY OF THE INVENTION 
These and other objects of the invention are accomplished in accordance 
with the principles of the invention by providing a surgical stapler which 
includes a longitudinal shaft assembly which is movable axially within a 
hollow stapler body which has a staple-carrying assembly at its distal 
end, the invention being characterized by a separable shaft segment 
removably connected to the main body of the portion shaft so that the 
shaft portion which projects from the stapler body is in two connectible 
but separable parts. i.e. the distal end of the shaft is made separable by 
the provision of the removable end segment which carries the anvil 
assembly. In a preferred form of the invention, the free end of the shaft 
which remains after the end segment is removed, is provided with movable 
tissue-restraining members to prevent tissue from slipping off the shaft 
end, and the removable end segment, which releasably interconnects with 
the free end of the shaft, if formed with a shroud or hood which depresses 
the restraining members when the end segment and the main body of the 
shaft are releasably joined. Also contemplated are separable puncturing 
means releasably connectible with the free end of the shaft prior to using 
the anvil-carrying segment, and means for rapidly binding tissue to the 
free end of the shaft adjacent the staple-carrying assembly of the stapler 
body and to the shaft segment carrying the anvil.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, and particularly to FIG. 1, there is shown a 
typical circular anastomosis surgical stapler of the type used for 
end-to-end anastomosis and thus known as an EEA Stapler and indicated 
generally by the reference number 10. A stapler of this nature is shown, 
for example in Noiles U.S. Pat. No. 4,351,466 in Conta U.S. Pat. No. 
4,573,468 and in Clanton U.S. Pat. No. 4,665,917, the disclosures of which 
are incorporated herein by reference. Stapler 10 has an elongated hollow 
tubular body or housing 12 which has an axial bore 14 through which 
extends a shaft 16 which can be reciprocated i.e. extended and retracted, 
in the body 12 by means of a control nut 18 at the proximal end of the 
instrument 10. The body 12 has at its distal end a staple-carrying 
assembly 20. In a conventional circular anastomosis surgical stapler, the 
shaft 16 carries at its distal end an anvil assembly 22 threadedly or 
fixedly engaged with it, i.e. the shaft 16 is continuous as it extends 
through the staple-carrying assembly 20 to the anvil assembly 22, which 
anvil assembly is rigidly connected to the entire shaft when it has been 
been screwed into place. 
In accordance with the invention, however, as seen in FIG. 2, the portion 
of the shaft which is visible when it has been extended out of the housing 
12 to its greatest length, is not a continuous shaft but, rather, has a 
frictionally-separable end portion or segment 25. The anvil 22 is fixedly 
secured to the distal end of the shaft segment 25. The 
frictionally-separable segment 25 can be frictionally engaged with the end 
portion of shaft 16 in any convenient manner but, in the embodiment 
illustrated and in a preferred form of the invention, the end portion of 
shaft 16 is hollow and formed with interior flexible detents 30. At the 
same time, shaft segment 25 is formed with a shaft portion 31 dimensioned 
to be received in the hollow of shaft 16 but of greater diameter than the 
space between detents 30. Shaft portion is formed with an annular recess 
32. The detents 30 are positioned to receive the proximal end portion 31 
of the shaft segment 25 between them and to engage in the recess 32 which 
is formed in proximal end portion 31 carried by the segment 25. 
Conveniently, the shaft end portion 31 may have a point 35 at its proximal 
end in order to facilitate guiding the portion 31 into the hollow distal 
end of the main body of shaft 16 when the segment 25 and the main body of 
shaft 16 are to be releasably interconnected. 
As seen in FIG. 3, the anvil of the releasable segment 25 is of 
conventional construction and has surfaces 36 for suitably crimping or 
clinching the ends of the staples when they are ejected from the 
staple-carrying end of the instrument and after they pass through the 
tissue to be stapled. As seen in FIG. 4, the staple-carrying distal end of 
body 12 contains a plurality of surgical staples (not shown) pointing 
towards the distal end of the instrument and arranged in two concentric 
annular rows. Shown in FIG. 4 are the openings 38 through which the 
staples are ejected. Conventionally, the staple-carrying assembly 20 also 
contains a circular knife 40 which is on the radially-inner side of the 
annular staple array. The staples and blade are of known construction and 
form no part of the present invention. In accordance with the invention, 
however, as previously mentioned, the distal end of the main shaft 16 is 
hollow and is interiorly formed with detents 30, the purpose of which has 
been indicated above. In addition, in accordance with a preferred form of 
the invention, the distal end of the main body of the shaft 16 is formed 
with spring-loaded tissue holders or restrainers 45. The restrainers 45 
are at least two in number but most suitably may be greater in number, 
such as the four restrainers illustrated in the drawings. They are 
connected to the shaft 16 by means of spring hinges 48 which permit the 
restrainers to lie flat against the shaft but normally urge the ends of 
the restrainers away from the shaft into an acute-angled position, as 
illustrated. Referring again to the right-hand portion of FIG. 2, which 
shows the releasable segment 25 of shaft 16, it will be seen that the 
shaft portion 31 previously mentioned is surrounded by an outer shroud 
member 37 which has in internal surface which is spaced from the shaft 
portion 31 by a distance at least as great as the length of the tissue 
restrainers 45. As will be apparent from FIG. 2, when the segment 25 is 
interlocked with the main body portion of shaft 16, by inserting the shaft 
portion 31 into the hollow end of shaft 16 until detents 30 are received 
in recess 32, the shroud 54 will strike and cause the tissue restrainers 
45 to lie closer to the surface of the distal end of shaft 16 and will 
enclose them as the detents 30 enter recess 32 and the separable segment 
25 is locked into place as a separable extension of shaft 16. 
In using the instrument of the invention, e.g. for an end-to-end 
anastomosis during rectal surgery, the sections to be joined by stapling, 
e.g., the ends of proximal bowel and the rectum, must be tied around the 
shafts 16 and 25 with purse-string sutures. This may be a exacting 
process, especially for the rectal end if deep in the pelvis. The 
instrument is inserted into the bowel and advanced until the anvil 
protrudes through the rectal lumen. The stapler is then opened fully by 
advancing the shaft 16. The shaft segment 25 with the anvil 22 attached to 
it is then separated from the shaft 16 by pulling the shaft segment 25 to 
release recess 32 from detents 30. As this occurs, tissue restrainers 45 
are urged outwardly by spring hinges 48 so that the sutured rectum, or 
other tissue to be stapled, will be held in place on the exposed end of 
shaft 16, and accidental dislodgement is effectively prevented. Such 
dislodgement frequently occurs when using currently constructed staplers. 
The sutured proximal bowel or other opposed tissue to be stapled is then 
advanced over the now-released and freely movable anvil 22. The distal 
purse string is then secured around the end of shaft 16 between the end of 
body 14 and restrainers 45 and the proximal purse string is similarly 
secured around shaft segment 25. Since the staplecarrying assembly 20 and 
the anvil assembly 22 are completely separate from each other, the surgeon 
has complete freedom of movement and visibility and is not hampered or 
constrained by limitations of the stapling instrument as he would have 
been when using instruments of the prior art. After the securing of the 
tissue has been completed, the shaft segment 25 is again interconnected 
with the main shaft 16 by inserting shaft end portion 31 into the hollow 
end of shaft 16 until detents 30 interlock in recess 32. While this is 
occurring, shroud 37 forces restrainers 45 downwardly and overlies and 
conceals them, leaving the tissue secured about the shaft 16 free to be 
stapled. The anvil 22, with the opposed tissue to be stapled secured about 
shaft segment 25, is then drawn toward staple-carrying assembly 20 the 
desired amount and the staples fired, the circular knife 40 simultaneously 
cutting two rings of tissue radially inside the staple line, thus creating 
the desired end-to-end anastomosis. The anvil 22 is then removed by 
disengaging end shaft portion 31 from detents 30 as described above. The 
anvil and its attached shaft segment 25 are then removed from the lumen by 
making a suturable opening in the wall of the bowel and removing the anvil 
assembly from the bowel lumen in the same manner as threadedly-engaged 
anvils are conventionally removed. The shaft 16 and the staple-carrying 
assembly 20 are removed from the opposed lumen in conventional manner 
simply by carefully withdrawing the instrument body. 
While end-to-end anastomosis has been described, for which the instrument 
is particularly adapted, it will be apparent that the improved instrument 
of the invention can be used for other anastomosis procedures such as 
end-to-side, side-to-side and side-to-end anastomoses. 
An important feature of the invention is that, by reason of the provisions 
of a two-part separable shaft, it permits optional use of shaft 
attachments or extensions other than the shaft segment 25 with its 
attached anvil 22. 
Thus, it sometimes occurs that the purse-string sutures are too tightly 
originally formed or the rectal end intentionally oversewn completely, 
either during this operation or during previous surgery, so that the 
instrument with interconnected anvil cannot be conveniently passed through 
the lumen unless the opening is enlarged. 
For this purpose, in accordance with the invention, there is provided a 
temporarily-attachable device. Thus, referring to FIG. 5, there is shown a 
puncturing and enlarging unit 50. Unit 50 has a sharply-pointed conical 
head 52 a shaft portion 54, corresponding to shaft end portion 31. Like 
shaft end portion 31, shaft portion 54 is formed with a recess 56 for 
reception of detents 30, and conveniently may have a pointed end 58 to 
guide it into the hollow end of shaft 16. It is also provided with a 
shroud 60. 
When it is desired to use unit 50, the anvil assembly with its shaft end 31 
is disengaged from shaft 16, simply by pulling it to release detents 30 
from recess 32, and it is replaced at the end of shaft 16 by inserting 
shaft portion 54 into the end of the hollow end of shaft 16 until the 
detents 30 engage in recess 56. The instrument 10, with the unit 50 
attached, is then used to pierce and open the closed end of the lumen so 
that the anvil and the staple-carrying assembly may readily pass through 
it. Thereupon, the instrument is withdrawn, the unit 50 disengaged and 
replaced by shaft segment 25 and its attached anvil 22, and the procedure 
of anastomosis can proceed as described above. 
In accordance with another aspect of the invention, means are provided for 
cooperating with the improved anastomosis instrument above described to 
facilitate securing tissue on the instrument for stapling in a rapid, 
convenient manner, thus avoiding the difficult task of saturing the edge 
of the rectal end around shaft 16. 
Thus, referring to FIG. 6, there is shown a perspective of a 
tissue-securing device 70 which comprises a rod 72 telescoped and slidable 
within a tube 74. The shells 76 and 78 are illustrated in FIG. 6 as 
cylindrical fragments in order to show details of construction. At its 
distal end tube 74 is secured to cylindrical shell 76. Rod 72 is secured 
to cylindrical shell 78 which is telescopingly slidable within shell 76. 
The relationship of telescoping shells 76 and 78 to each other is such 
that when rod 72 is extended from tube 74, the distal edge of shell 78 
will extend beyond the distal edge of shell 76, but rod 72 can be 
retracted so that the distal edge of shell 78 will coincide with the 
distal edge of shell 76. 
The mechanism for telescopingly moving shells 76 and 78 is shown at the 
right in FIG. 6. The free end of rod 72 is threaded, as seen at 77. An arm 
79 is pivotally connected to an arm 80. Arm 78 is threadedly-engaged with 
threaded end 76. Arm 80 is bifurcated at its end, as seen at 82, and is 
received in a slot (not shown) in rod 72 adjacent the free end 84 of tube 
74. Threaded end 76 also carries a nut 86. The device 70 is employed to 
discharge an elastic band of circular cross-section 88. Thus, the band 88 
is placed about the shell 78. When shell 78 is retracted within shell 76 
by squeezing arms 78 and 80, band 88 is forced off shell 78 and 
discharged. It is a feature of the invention that the device 70 can be 
used to secure tissue to be stapled about shaft 16 and about releasable 
segment 25. For this purpose, shells 76 and 78 are given an internal 
diameter somewhat smaller then the external diameter of the 
staple-carrying assembly 20 and the external diameter of the anvil 22 but 
sufficiently greater than the external diameter of rod 16 and segment 25 
such that the shells will easily receive the ends of rod 16 and of segment 
25 as well as tissue overlying them. Thus, the device 70 is used after 
tissue to be stapled has been placed about the distal end of body 12 and 
about the free end of shaft 16, as well as about shaft segment 25, but 
before the anvil assembly has been united with the end of shaft 16. For 
this purpose shell 78 is extended, the round elastic band 88 is placed 
about it, and shell 78 is positioned to enclose the free end of shaft 16 
and the tissue overlying it. Then handles 79 and 80 are squeezed, and the 
band 88 is discharged as shell 78 is retracted within shell 76. The band 
88 thereupon secures the tissue about the shaft. Shell 78 is again 
extended by separating handles 79 and 80, a band 88 is placed about shell 
78, shell 78 is positioned to surround the tissue overlying shaft segment 
25, and the procedure above described is repeated to discharge the band 88 
and secure the tissue about shaft segment 25. The above-described 
procedure easily and safely fixes the tissue ends, e.g. the bowel ends, 
permitting an improved anastomosis. In particular, this procedure prevents 
the bowel distal end which is to be stapled from slipping off the end of 
the instrument. When the stapling device 10, with its circular knife 40, 
is actuated, the portion of the tissue within the staple line cut out by 
the knife will include the bands 88 so that they will be removed from the 
lumen when the device and the separable anvil assembly 22 with attached 
segment 25 are removed. 
It will be obvious that various changes and modifications may be made 
without departing from the invention as defined in the appended claims and 
it is intended, therefore, that all matter contained in the forgoing 
description and in the drawing shall be interpreted as illustrative only 
and not as limitative of the invention.