U.S. patent number 3,815,476 [Application Number 05/125,077] was granted by the patent office on 1974-06-11 for gas powered driving unit for surgical instrument.
This patent grant is currently assigned to United States Surgical Corporation. Invention is credited to Graham W. Bryan, David T. Green.
United States Patent |
3,815,476 |
Green , et al. |
June 11, 1974 |
GAS POWERED DRIVING UNIT FOR SURGICAL INSTRUMENT
Abstract
A surgical instrument for applying sterilized staples from a
disposable staple-carrying cartridge to the disunited skin of a
patient in order to effect a joining of the skin. The instrument
consists of an anvil adapted to lie flush with the skin, a
disposable cartridge housing a plurality of staples which are to be
folded around the anvil, and a pusher for bending the staples
around the anvil. The pusher is U-shaped with chamfers on the arms
thereof to effect the bending with a minimum of force. A
gas-powered unit serves to eject and form the staples in a neat and
uniform manner. A novel disposable gas cartridge is also
disclosed.
Inventors: |
Green; David T. (Norwalk,
CT), Bryan; Graham W. (Ridgefield, CT) |
Assignee: |
United States Surgical
Corporation (Baltimore, MD)
|
Family
ID: |
26823237 |
Appl.
No.: |
05/125,077 |
Filed: |
March 17, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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852822 |
Aug 25, 1969 |
3643851 |
|
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Current U.S.
Class: |
91/410; 227/130;
91/469 |
Current CPC
Class: |
A61B
17/0684 (20130101); A61B 2017/00544 (20130101); A61B
2017/00548 (20130101) |
Current International
Class: |
A61B
17/068 (20060101); A61B 17/00 (20060101); B25c
001/04 (); F15b 013/04 () |
Field of
Search: |
;91/318,356,398,410,469
;227/130 ;173/15-17 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cohen; Irwin C.
Attorney, Agent or Firm: Fleit, Gipple & Jacobson
Parent Case Text
REFERENCE TO ANOTHER APPLICATION
This application is a division of Ser. No. 852,822, filed August
25, 1969, now U.S. Pat. No. 3,643,851.
Claims
What is claimed is:
1. A gas-powered driving unit for converting gas pressure into a
single forward thrust and for then returning to its static
readiness position, the unit comprising: a body defining a
plurality of chambers including an inlet chamber and a piston
chamber; an inlet port in said body for the introduction of
pressurized gas into said body; a piston mounted to reciprocate
between a forward and returned position in said piston chamber;
spool valve means intermediate said inlet port and said piston for
sealing said inlet port, said spool valve means mounted to
reciprocate in said body into and away from sealing engagement with
said inlet port and away from and into sealing engagement with said
piston chamber; biasing means for urging said piston towards said
inlet port, said biasing means further biasing said spool valve
means via said piston into sealing engagement with said inlet port
when said piston reciprocates to its return position; sealing means
connected to said spool means and defining said inlet chamber
between said sealing means and said inlet port; the area of said
spool valve means exposed to said piston chamber and the area of
said spool valve means and said sealing means in the inlet chamber
when said spool valve means is in sealing engagement with said
piston chamber being such that equal pressure in both said chambers
urges the spool means towards said inlet port: a transfer port
through said spool valve means communicating between said inlet
chamber and said piston chamber; a seal connected to said piston
for preventing the passage of pressurized gas past said piston and
out of said piston chamber; exhaust means for relieving pressure
from said piston chamber for permitting the return stroke of said
piston; and triggering means connected to said body for overcoming
the bias imparted to said spool valve means by said biasing means
so that the gas pressure in said inlet port can be introduced into
said inlet chamber and thence through the transfer port to the
piston chamber to cause said piston to reciprocate to its forward
position, and further so that when pressure substantially equalizes
in said piston chamber and said inlet chamber via said transfer
port, said spool means moves into sealing engagement with said
inlet port whereupon the gas pressure in said piston chamber is
relieved and said biasing means moves said piston back to its
return position.
2. The unit as defined in claim 1 wherein said transfer port is of
a small orifice size so that a finite period of time elapses
between the time when said spool valve means moves out of sealing
engagement with said inlet port and the time when enough
pressurized gas flows through said transfer port to equalize the
pressure in said inlet chamber and said piston chamber, said finite
time period being sufficiently long to enable the piston to
substantially move from its return position to its forward position
under the influence of the gas pressure in the piston chamber.
3. The unit of claim 1 wherein said exhaust means is an exhaust
port communicating on one side with said transfer port and said
piston chamber during the return stroke of said piston and on its
other side with the atmosphere.
4. The unit as defined in claim 3 wherein said exhaust port is of a
small orifice size so that the pressure of the gas in said piston
chamber remains high enough to move said spool valve into sealing
engagement with said inlet port and keep said spool valve in
sealing engagement with said inlet port until said piston means
returns to its return position so that said biasing means can then
urge said spool valve means into sealing engagement with said inlet
port via said piston.
5. The unit as defined in claim 3 wherein said sealing means
includes first and second seals which define a chamber
therebetween, said body having a vent port communicating on one
side with said chamber intermediate said first and second seals and
on its other side with the atmosphere.
6. The unit as defined in claim 1 wherein said piston means
comprises a piston and an output shaft integral therewith.
Description
BACKGROUND OF THE INVENTION
The use of sterilized staples for medical applications has been
steadily and rapidly increasing in popularity. However, the use has
largely been restricted to applications wherein the tissue to be
stapled can be positioned between the staple-ejecting unit and the
anvil of the instrument. Where the tissue joint is to be made on
the external skin of the patient, medical instrumentation is
noticeably weak. Thus, there exists a void in modern surgical
instruments making effective use of the staple in uniting external
tissue.
There is another void in the field of modern surgical stapling
instrumentation. Despite the wide use of sterilized staples for
pefforming suture-like maneuvers, it has customarily been difficult
for the surgeon, or assistant, to perform successive stapling
operations in a way so that the staples are uniformly injected and
shaped. The main reason for the resulting disuniformity of
injection and shaping operations is that the surgeon is unable to
exert a constant manipulative force on the instrument which he
uses. Another reason is that after numerous stapling operations,
the hand of the surgeon tends to tire, thus adding to the
disuniformity of staple injection and shaping.
It is toward the elimination of the above-noted drawbacks of
presently existing surgical stapling instruments, that the present
invention is directed.
SUMMARY OF THE INVENTION
The present invention relates to a surgical instrument for stapling
together disunited segments of the external skin of a patient.
Since this instrument functions externally to the body, the anvil
serving to form the staple must be and is, at all times, external
to the skin being stapled. More particularly, the anvil is adapted
to rest on the external skin of the patient and to bend the staples
so that they tightly grip and join the severed skin.
The staple is acted upon by a U-shaped pusher element having a
chamfer on each leg thereof so that the staples are acted upon by
forces remote from the points about which they are bent. In this
manner, less force is required to bend the staples. The central
region of each staple is made to contact the anvil. The pusher
element then bends the staple around the anvil, the chamfer
surfaces reducing the force required for such bending, and the
U-shape of the pusher allowing the pusher to partially encircle the
anvil during the bending operation for forming the staple. The
anvil releases the staple by means of a spring and the stapling
maneuver is complete.
In the instrument of the present invention, a plurality of staples
are housed in a disposable cartridge. These staples are housed in
such a manner that only a small area of the instrument need contact
the patient. For this reason, the stapling instrument of the
present invention may also be used for the stapling of internal
fascia.
The instrument of the present invention is powered by a disposable
gas cartridge. Thus, there is complete uniformity of staples from
one stapling operation to the next. Also, there is no fatigue of
the surgeon or his assistant since the gas-powered unit is
activated by a slight movement of a lever or trigger. In operation,
the gas-powered staple-ejecting unit is activated by the operator
and performs its stapling operation, returning to its initial state
for further activation in a minimum of time and with a maximum of
efficiency. The power unit is simple in design, contains but few
moving parts and is a repeating unit having an extremely long life
cycle.
The cartridge contains 25 staples. Each staple lies in the threads
of a pair of adjacent screws and each is propelled one step when
the screws are simultaneously turned one revolution. The power unit
is fired and a rod-like element initiates the operation of a
gearbox and simultaneously drives the pusher forward. The gearbox
ensures that a staple is put in a readiness position before the
pusher reaches the contact area. The pusher unit then automatically
returns to its rearward position and the instrument is put in
readiness for another stapling maneuver.
The present invention thus provides a surgical stapling instrument
which fills the gaps noted above with regard to the instrumentation
known to the prior art. Staples may be used to unite the external
skin of a patient and may be uniformly shaped without causing
fatigue in the surgeon.
As noted above, the instrument of the present invention is powered
by means of a sterilized disposable gas cartridge. It is customary
when gas-powering units are employed, to provide the recipient
device with a pin for puncturing the seal in the gas cartridge. It
has been found, however, that the pin wears rapidly and thus
detracts from the useful life of the gas-powered device.
The present invention contemplates that a gas cartridge be fitted
with its own puncturing mechanism, thereby adding to the life of
the basic instrument. In this manner, a sterilized gas cartridge
with its puncturing mechanism and a sterilized and filled staple
cartridge may be packaged together so that the reloading operation
is greatly facilitated.
Accordingly, it is one object of the present invention to provide a
surgical stapling instrument for stapling disunited portions of the
external skin of a patient.
It is another object of the present invention to staple the skin of
the patient in such a manner that a minimum of force if required to
form the staple during the maneuver.
It is yet a further object of the invention to provide a stapling
instrument having a disposable staple-carrying cartridge.
It is a further object of the invention to provide a medical
instrument for stapling the skin of a patient, which instrument is
powered by a gas under pressure.
It is still another object of the present invention to provide a
unique and disposable pressurized gas-powering assembly.
It is yet a further object of the invention to provide a
gas-powered driving mechanism which is simple in design, economical
in cost and is yet efficient and long lived.
These and other objects of the invention, as well as many of the
attendant advantages thereof, will become more readily apparent
when reference is made to the following description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view, partially in section, showing the skin
stapler of the present invention;
FIG. 2 is an enlarged side view, partially in section, of te
mechanism shown in FIG. 1 after the cartridge is mounted and ready
for use;
FIG. 3 is a top view of the cartridge of the present invention;
FIG. 4 is a bottom view of the cartridge shown in FIG. 3;
FIG. 5 is an enlarged view of the rear portion of the cartridge
shown in FIG. 3 with a portion of the cover removed;
FIG. 6 is a cross-section taken along lines 6--6 of FIG. 5;
FIG. 7 is a cross-section taken along lines 7--7 of FIG. 6;
FIG. 8 is an enlarged view of the front portion of the cartridge
shown in FIG. 3 with the cover partially removed;
FIG. 9 is a cross-section taken along lines 9--9 of FIG. 8;
FIG. 10 is a cross-section taken along lines 10--10 of FIG. 8;
FIG. 11 is a front view of the cartridge shown in FIG. 3;
FIG. 12 is a top view of the pusher element forming a part of the
present invention;
FIG. 13 is a side view of the pusher element shown in FIG. 12;
FIGS. 14 through 17 are sequential views showing the formation of a
staple during a stapling operation;
FIGS. 18 through 22 show the sequential formation of a staple in
the skin of a patient;
FIG. 23 is a cross-section through the gas-powered driving
mechanism of the present invention;
FIGS. 24 through 28 are drawings showing the sequential steps
involved in ejecting and forming a staple with the gas-powered
mechanism shown in FIG. 23;
FIG. 29 is a front view of the main body portion of the skin
stapler shown in FIG. 1;
FIG. 30 is a top plan view of the gearbox housing;
FIG. 31 is a cross-section through lines 31-31 of FIG. 30;
FIG. 32 is a side elevation of the gear arrangement shown in FIG.
31;
FIG. 33 is a cross-section of the gearbox through lines 33--33 of
FIG. 30 in its retracted, or readiness, position;
FIG. 34 is a view similar to FIG. 33 but with the gearbox in its
stapling position;
FIG. 35 is a view similar to FIGS. 33 and 34, showing the moving
parts of the gearbox when returning from the position shown in FIG.
34 to the position shown in FIG. 33;
FIG. 36 is a side view of a second embodiment of the main body
portion of a skin stapler constructed in accordance with the
present invention;
FIG. 37 is a sectional view through lines 37--37 of FIG. 36 with
the gas-cartridge assembly removed;
FIG. 38 is a sectional view through lines 38--38 of FIG. 36;
and
FIG. 39 is an exploded perspective view of the gas cartridge and
piercing mechanism shown in FIGS. 36 through 38.
DETAILED DESCRIPTION OF THE DRAWINGS
In FIG. 1, the skin stapler of the present invention is shown
generally at 10 and comprises a disposable staple cartridge
indicated generally at 12 and a main body portion indicated
generally at 14. The main body portion 14 has a region 16 serving
as the handle which the surgeon holds during use. The handle 16
further serves to house the gas-powered firing mechanism 17
including a source of CO.sub.2 gas. The forwardmost region of the
main body portion 14 defines a cartridge-mounting assembly 18 for
positioning and holding the cartridge 12. Intermediate the handle
16 and the cartridge mounting assembly 18 is a gearbox region 19.
Region 19 houses the gearbox which synchronizes the movements of
the elements forming a part of the inventive skin stapler.
In FIG. 1, the cartridge 12 is in the process of being seated in
the cartridge-mounting assembly 18. It can be seen that the
assembly 18 has defined therein a cavity 20, this cavity being of
such dimensions as to allow the angular insertion of the cartridge
12. A hand operated semicylindrical cam 22 is rotatably mounted on
the assembly 18.
When the cartridge 12 is being inserted or removed from the main
body portion 14, the cam 22 is in the position shown in FIG. 1. To
lock the cartridge 12 in the main body portion 14, cam 22 is
rotated 180.degree. until it takes the position shown in FIG. 2 and
securely contacts the bottom of cartridge 12 with its camming
surface 23. The cartridge 12 is held in horizontal alignment with
the main body portion 14 by means of a pair of upwardly extending
flanges 24 on the cover plate of the cartridge 12. Flanges 24
engage a pair of recesses 26 defined in the cartridge mounting
assembly 18.
As is best shown in FIGS. 6 and 11, the two flanges 24 extend
upwardly from the rear end of the cartridge cover and are spaced
apart. This spacing is provided to enable a driving member 28 (FIG.
2) to reciprocate between the two flanges 24.
As shown in FIG. 1, the driving member 28 has an elongated central
region 29. A pusher-engaging extension 30 is positioned at the
extreme front end and an inclined surface 32 is positioned at the
mid section of the driving member 28. The inclined surface 32 is
adapted to engage a slidable plunger 34 which is spring biased
upwardly by a spring 35.
In FIG. 1, the driving member 28 is shown in its rearwardmost
position to allow for the insertion or the removal of the cartridge
12. In this position, the plunger 34 is maintained in its uppermost
position by the force of the biasing spring 35. When the member 28
is driven forward during a stapling operation, the plunger 34 is
acted upon by the surface 32 and is forced downward against the
biasing force of spring 35. The functions of these elements are
described in more detail below.
The configuration of the cartridge 12, and its operation, will now
be explained with reference to FIGS. 3 through 13. The cartridge 12
is defined by a body 36 adapted to be covered by a cover plate 38.
The body 36 has provided thereon a pair of alignment extensions 40
which serve to engage the cover plate 38 at respective recesses 42
provided therein. This is best shown in FIGS. 4 and 5. The body 36
of the cartridge 12 is fitted with a pair of cylindrical
depressions 44, shown best in FIG. 7. Depressions 44 extend
substantially the entire length of the body 36 and serve to
position a pair of rotatably mounted screws 46.
As best seen in FIGS. 7 and 8, the pair of depressions 44 are
defined in the body 36 of the cartridge 12. These depressions 44
serve to define ledges 49 of lateral walls 51, which ledges and
walls function to guide a plurality of staples 50.
From FIGS. 6 and 7, it can be seen that the ledges 49 and lateral
walls 51 guide the staples 50, over a substantial length of the
cartridge, at a level beneath the external circumference of each
screw 46. This is made possible since the screws 46 are provided
with threads 52 for guiding and propelling the staples 50 along the
ledges 49 and between the walls 51.
A pusher plate 54 covers the staples 50 and slides within an
indentation 56 provided in the cover plate 38, the pusher plate 54
being guided by the top of the screws 46 and the bottom of the
cover plate 38. The pusher plate 54 serves to hold each staple 50
against the ledges 49 except during a driving operation. Then, the
forwardmost staple is propelled forward and away from the cover of
the pusher element 54.
Each screw 46 is provided, at its rearwardmost end, with an
extension 58. Each extension 58 is unthreaded, is rotatably held in
a cylindrical recess 59 in the body 36, and it fitted at its
extremity with a flat extension 60. See FIGS. 5 and 6.
In FIGS. 12 and 13, the configuration of the pusher element 54 is
illustrated. The pusher element 54 is in the form of a flat plate
having a pair of upwardly extending guide projections 66 centered
thereon. Projections 66 are adapted to slide in recesses 67 on the
top of the cover plate 38. The rearwardmost region of the pusher
element 54 is cut out at 68 and is adapted to be engaged by the
pusher-engaging extension 30 on the driving member 28, described
with reference to FIG. 1. The extension 30 reaches the hole 68
through a slot 69 provided in the cover plate 38. The forwardmost
region of the pusher element 54 is U-shaped, defining a pair of
tines 70. As best seen in FIGS. 8, 9, 12 and 13, the tines 70 are
V-shaped in order to best guide the staples 50 during the
staple-discharging operation. For reasons which are explained
below, each tine 70 is provided with a chamfer 72.
At the forwardmost region of the cover plate 38, and as illustrated
in FIGS. 1, 3, 9 and 11, projects an anvil 62. The anvil 62 is an
extension of the top of the cover plate 38 and curls into the plane
of the pusher element 54. The anvil 62 is fitted with
staple-ejecting springs 64 for forcing the staples out of the
region of the anvil 62 after the completion of each stapling
operation. It should be evident that the pusher element 54 moves
the springs 64 out of the staple-forming plane during the stapling
operation and releases the springs when it begins to retract. Once
the pusher element 54 is retracted from the anvil area, the springs
64 urge the staple 50, just formed, out of the plane of the
pusher.
As best shown in FIG. 3, the tines 70 of the pusher element 54 are
spaced apart a distance sufficient to comfortably accommodate the
anvil 62. More particularly, with reference to FIG. 17, the
distance between the tines 70 is equal to the width of the anvil
62, plus twice the diameter of a staple 50, plus a small clearance
to avoid "sluggish" operation.
In loading the cartridge 12, the following procedure may be used.
The screws 46 may be fitted into their respective cylindrical
depressions 44. Then the staples 50 may be inserted between the
lateral walls 59 of the body 36. The screws should be in the
position shown in FIG. 5 with the flat extensions 60 aligned and
vertical. The pusher element 54 is then fit over the staples 50 and
the cover plate 38 is put in position. Once, this procedure has
been followed, the cartridge 12 is ready to be loaded into the
instrument.
The screws 46 are threaded so that when they, by means of the
extensions 60, are rotated through 360.degree., each staple moves
one staple unit. A "staple unit" may be defined as that distance
required to move the second staple from its readiness position into
a position ready to be fired. Thus, in FIGS. 8 and 9, one staple
unit is shown at a.
With reference now to FIGS. 8, 9 and 10, the positioning of the
forwardmost staple 50 will be described. This staple is, initially,
one staple unit from a position ready for firing. The pusher
element 54 is then in its rearwardmost position, which position
holds all staples in the threads 52 of the screws 46.
As is seen in FIG. 9, each ledge 49 is terminated as its
forwardmost region in an inclined surface 74. Surface 74 serves to
guide the point of the forwardmost staple 50 upwardly and into the
plane of the pusher element 54 during the forward thrust of the
pusher. Simultaneous with the action of the surface 74, the
forwardmost portion of each screw 46 serves to raise the
cross-piece of the first staple 50 into the plane of the pusher
element 54. This is best shown in FIG. 10 which illustrates the
forwardmost portion of the screw 46. The direction of rotation of
screw 46 is indicated by arrow 75. It is seen that the thread depth
decreases from a maximum at 76 to a minimum at 78. The thread depth
at 76 is equal to the thread depth uniform throughout the thread
save for the most forward region. The depth of the thread at 78 is
zero. Thus, when the cross-piece of a staple rides along the screw
at 78, it is in the plane of the pusher element 54.
The staple-ejecting and guiding operation will now be explained.
When the pusher element 54 is activated, it is thrust forward by
the member 28. Before, however, the pusher element 54 reaches the
contact area, the inclined surface 32 on member 28 causes plunger
34 to be depressed, thus advancing a staple into stapling position.
Once the staple is properly positioned, pusher element 54 reaches
the contact area and forces the first staple (See FIGS. 8 and 9.)
out of the cartridge 12 and against the anvil 62. When the pusher
element 54 reaches its forwardmost position, its direction of
travel is reversed (it being controlled by the driving member 28
shown in FIGS. 1 and 2). At a time during the rearward journey of
the pusher element 54, the inclined surface 32 on the driving
member 28 releases the plunger 34, allowing the plunger and the
gearing mechanism to be put in readiness for the next stapling
operation. The gear mechanism causes the two screws 46 to turn
slightly better than one revolution during the forward movement of
the pusher element 54. This will be explained below.
The interaction of the pusher element 54, the staples 50, the ledge
49 with its inclined surface 74 and the screws 46 with their
diminishing thread arrangements will now be explained. A gearbox,
described below, turns each screw 46 through slightly more than one
revolution during the forward stroke of the pusher element 54,
thereby advancing each staple but the first, slightly more than one
staple unit. The forwardmost staple moves only one staple unit and
into a readiness position because of the lack of threads at the
forward ends of the screws 46. When the screws 46 turn, thereby
advancing each staple, the forwardmost staple 50 is simultaneously
acted upon by the ledge 74 and the diminishing thread of the screws
46. In this manner, the first staple is raised from its position
below the pusher element 54 into the plane of the pusher, while
remaining parallel, at all times, to the plane of the pusher. This
is done while the pusher moves forward but before it reaches the
contact area. Once the first staple is ready to be expelled from
the instrument, the pusher element 54 makes contact with the
staple.
The disposable cartridge of the present invention may house any
number of staples, but is shown to house, in this example,
twenty-five. It is therefore possible that more than one cartridge
is required during a single operation. It becomes important, then
to keep the surgeon advised as to the number of staples remaining
in his disposable cartridge. The present invention provides for the
indication of the number of remaining staples.
Reference should now be directed to FIGS. 4 through 7. Beneath each
cylindrical depression 44 in the body 36 is a small rectangular
depression 80. Depressions 80 extend substantially the entire
length of the body 36 and communicate with depressions 44. Through
the bottom of body 36 extend twenty-five tapered bores 82. As is
best seen in FIG. 7, the recesses 44 communicate with the bores 82
by means of a plurality of cylindrical bores 84 of a smaller
diameter than the smallest diameter of the tapered bores 82.
A pair of pads 86 and 88 of a rectangular shape are housed within
the slide in the recesses 80. Each pad 86 and 88 is provided with a
cylindrical extension 90. Each extension 90 serves to ride within
the thread 52 of a screw 46.
As shown in FIG. 4, the tapered bores 82 are staggered throughout
the length of the cartridge 12. As is also seen in FIG. 4, the pads
86 and 88 ride in their respective recesses 80 in alignment.
Because of the alignment between pads 86 and 88 and the staggered
arrangement of bores 82, only a single pad at a time is visible
through a bore.
In operation, the pads 86 and 88 are positioned in alignment with
the rearwardmost bore 82, as shown in FIG. 4. This bore is numbered
"25" and indicates that 25 staples remain in the cartridge.
Initially, pad 88 is visible through this bore. After one staple
has been ejected from the cartridge, each screw 46 has been rotated
360.degree.. Since the projections 90 on the pads 86 and 88,
respectively, engage the threads 52 of the screws 46, the pads move
one staple unit. The bores 82 are separated by one staple unit.
Consequently, pad 86 is visible through bore 82 which is labeled
"24". This staggering relationship of visible pads continues until
pad 88 is visible through the bore 82 referenced 1, this indicating
that one staple remains. When the last staple is ejected, the pads
86 and 88 are both masked by the body 36. In this manner, the
surgeon is constantly appraised of the number of staples remaining
in this instrument.
With reference now to FIGS. 14 through 17, the interaction between
the pusher element 54, a staple 50 and the anvil 62 is explained.
In each of these four figures, the pusher element 54 is shown to be
moving toward the left of the page, in the direction of the
arrow.
In FIG. 14, the relative positions of the pusher element 54 and a
staple 50 are shown at impact. In FIG. 14, the pusher element is
shown in the contact area. It is evident, then, that the screws
have already been turned to advance the staples 50.
The pusher element 54 moves forward from the position shown in FIG.
14 until the staple 50 contacts the anvil 62, the staple 50 being
guided by the V-shaped surface of the pusher tine 70. The pusher 54
is driven to the left and, because of the chamfers 72 in the tines
70, staple 50 is easily bent around the anvil 62. After the pusher
element 54 advances slightly, the staple takes the shape shown in
FIG. 16, still being guided by the V-shape of the pusher tine. The
chamfer surface allows a bending force to be exerted on the staple
50 at points remote from the anvil 62. In this manner, the required
initial bending force is reduced.
Once the staple is in the position shown in FIG. 16, the bending
force is moved from the outermost region of the chamfer to the
innermost region. However, because of the build-up of inertial
forces, bending is still easily accomplished. The pusher element
advances until it reaches the position shown in FIG. 17. In this
position, the staple 50 is substantially rectangular and has its
points in engagement.
With reference now to FIGS. 18 through 22, the formation of the
staple with respect to the skin will be explained. The external
skin of the patient is shown at 92 and is split at an incision 94.
The function of the skin stapler of the present invention is to
securely fasten the two segments of skin 92 and to maintain the
fastened position neatly and securely to facilitate the healing
process.
As seen in FIG. 18, the front end of the skin stapler is pressed
against the skin of the patient covering the incision 94. If
properly positioned, the anvil 62 is centered with respect to the
incision 94. The member 28 is activated and the pusher element 54
begins its forward journey. Simultaneously, the staples 50 are
guided forward. When the pusher element 54 reaches the contact
area, the forward staple is ready to be ejected. The pusher
contacts the first staple, as shown in FIG. 18. Pusher element 54
then expels the staple 50 from the cartridge and drives same until
it contacts the anvil 62, as shown in FIG. 19. In this Figure, it
is seen that the staple pierces the skin of the patient.
In FIG. 20, the staple is shown when beginning to crimp the skin
92. In this position, the staple is formed as described above with
respect to FIG. 16.
The staple is then completely curled around the anvil 62 so that it
takes the shape illustrated in FIG. 17. The corresponding position
of the staple with respect to the skin is shown in FIG. 21.
During the forward thrust of the pusher element 54, the tines 70
move the springs 64 out of the staple plane. After the stapling
operation is completed and the pusher begins to return to its rest
position, springs 64, associated with the anvil 62, serve to eject
the staple 50 from the anvil. The skin 92 is then free, under the
force of sub-surface tissue, to expand toward the crossbar of the
staple. This is shown in FIG. 22.
Since only the forwardmost portion of the skin stapler 10, which
portion is relatively small, contacts the patient during a stapling
operation, the stapler of the present invention is quite versatile.
It may be used to staple external skin or an internal organ. This
has never before been possible in the prior art.
The pusher element may be driven by any of a large number of
configurations. It may be driven manually or it may be driven by
springs. The present invention, however, contemplates that the
pusher element be driven by a gas under pressure. More
particularly, the present invention contemplates that the pusher
element be driven by a charge of carbon dioxide housed within small
pressurized and disposable tanks.
With reference, now, to FIGS. 23 through 28, the gas-powering unit
of the present invention is described.
With reference first to FIG. 23, the configuration of the drive
mechanism is as follows. The drive mechanism is shown generally at
100 and comprises a gas inlet port 102, a spool 104, a pair of
diaphragm seals 106 and 108, respectively, a transfer port 110
extending from one side to the other of the spool 104, a piston 112
sealed against the wall 114 of a piston chamber 134 by means of a
rolling diaphragm 115 and a spring 117 serving to resiliently bias
the piston 112 upwardly. Secured to the piston 112 is an output
shaft 116 provided with a notch 118. The uppermost part of the
output shaft 116 is designated 120 and serves, under the action of
spring 117, to exert an upward force on the spool 104. A seal 122
is defined at the opening of the gas inlet port 102 and prevents
the escape of gas from the inlet port 102 when contacted by the
spool 104. A vent 124 and an exhaust 126 are provided and
communicate with a vent chamber 128 and an exhaust chamber 130,
respectively. An inlet chamber 132 communicates with the inlet port
102.
With reference, now, to FIGS. 24 through 28, the operation of the
power unit 100 will be explained. As noted above, when the spool
104 is acted upon by the spring 117, it impinges upon the seal 122,
thus preventing the entrance of the pressurized gas into the inlet
chamber 132. The pressure acting on the top of spool 104 is less
than the force exerted by the spring 117 since the pressure in the
inlet port acts on a small area when spool 104 abuts seal 122.
In FIG. 24, a trigger mechanism 136 is shown pivoting around a
pivot 138. The forwardmost end of the trigger 136 engages the notch
118 in the output shaft 116. Thus, when the trigger 136 is
activated, the force exerted by the spring 117 is overcome and the
spool 104 is driven from the seal 122, downwardly, off the inlet
port 102, by the gas under pressure. When the spool 104 reaches the
bottom of the exhaust chamber 130, the exhaust port 126 is sealed
with respect to the pressurized gas in the inlet port 102. The
pressurized gas then flows through the inlet port 102, into the
inlet chamber 132, then through the transfer port 110 and into the
piston chamber 134. The pressure exerted by the gas drives the
piston 112 downwardly and into the position shown in FIG. 25.
Initially, the pressure in the piston chamber 134 is lower than the
pressure in the inlet chamber 132 due to the restriction in the
transfer port 110. The pressure in the piston chamber 134, however,
rapidly builds up until it overcomes the pressure in the inlet
chamber 132. The pressure in the piston chamber overcomes the
pressure in the inlet chamber because the piston chamber acts on a
larger area (the bottom of spool 104) than does the inlet chamber
pressure (which acts on the top of diaphragm 106).
As a consequence the area differential noted above, the pressure in
the piston chamber 134 drives the spool 104 upwardly, thus sealing
the inlet port when the spool again contacts seal 122. This is
shown in FIG. 26. The pressure in the piston chamber 134 at this
point is directly proportional to the ratio of the areas between
the upper and lower diaphragm seals 106 and 108. The pressures
inside the system then tend to equalize.
The gas in the piston chamber 134 is now free to escape through the
restricted exhaust port 126 and into the atmosphere. At the same
time, the spring 117 forces the piston 112 upwardly, thus
maintaining a back pressure on the lower diaphragm 108 and thus
holding the spool 104 against the seal 122. This continues until
the upper region 120 of the output shaft 116 contacts the spool
104. Once this contact occurs, the action of the spring 117
maintains the spool 104 against the seal 122. An intermediate step
is shown in FIG. 27, and the final step is shown in FIG. 28. When
the system reaches the position shown in FIG. 28, it is ready for
another firing operation. It should be noted that in FIG. 28, all
regions of the mechanism but for the inlet port 102 are held at
atmospheric pressure. The notch 121 on the member 120 allows
chamber 132 to communicate with the exhaust port 126,
notwithstanding the contact between element 120 and the port
110.
The vent 124, communicating with the vent chamber 128, is provided
to ensure that sluggish operation of the spool and pistons is
prevented. In this manner, no pressure buildup occurs between
diaphragms 106 and 108.
With particular reference, now, to FIG. 2 and FIGS. 29 through 35,
the construction and operation of the gearbox will be explained. As
best seen in FIG. 2, the rear portion of the driving member 28 is
fitted with a yolk 150 adapted to be engaged by the forward end of
the output shaft 116. When the power unit 17 is fired, the output
shaft 116, the driving member 28 and the pusher element 54 are
driven forward and effect the formation of a rectangular staple
against the anvil 62.
When the member 28 is thrust forward, the inclined surface 32,
integral with member 28, moves forward and engages the plunger 34,
which plunger 34 moves downwardly against the compression in the
biasing spring 35.
As is best shown in FIG. 2, the front surface of the plunger 34 is
provided with a notch 152, which notch engages a flange 154 fitted
on the bottom of the rear surface of a triangular carrier plate
156. Thus, when the member 28 is thrust forward and the inclined
surface 32 engages the plunger 34, the notch 152 in the plunger 34
causes the triangular carrier plate 156 to move downwardly due to
the interaction between the notch 152 and the flange 154. In FIG.
34, it can be seen that the flange 154 extends a substantial
distance across the triangular carrier plate 156, which carrier
plate 156 is adapted to pivot at 157. This arrangement is further
shown in FIG. 35 where there are also shown a pair of pins 161 and
163, mounted in the plunger 34, which pins serve to prevent wear on
the flange 154 of the triangular carrier plate 156.
In FIGS. 2 and 33, the relative positions of the plunger 34 and the
triangular carrier plate 156 are shown when the driving member 28
is out of engagement with the plunger 34. FIG. 34 shows the
relative positions of these elements when the plunger 34 engages
the inclined surface 32 on the driving member 28 during the
stapling operation. When comparing FIGS. 33 and 34, then, it is
readily seen that when the plunger 34 moves downwardly, the carrier
plate 156 pivots in a counterclockwise direction around its pivot
point 157.
With continuing reference to FIG. 33, a pawl 158 is shown mounted
on the triangular carrier plate 156 by means of a pivot pin 160.
The forwardmost surface of the pawl 158 is adapted to engage the
surface of a six-toothed ratchet 159. It is seen, though, that in
its rest position, the pawl 158 is out of engagement with the teeth
of the ratchet 159. The movement of the pawl 158 is restricted by a
pin 162, mounted on the rear surface of the pawl and extending
through a hole 164 in the carrier plate 156. A second pawl 168 is
pivotally mounted on a pin 170 secured to the housing of the
gearbox and thus independent of both the carrier plate 156 and the
pawl 158. Pawls 158 and 168 are, however, biased towards the
ratchet 159 by means of a spring 166. Spring 166 may be replaced by
a pair of tension springs (not shown) mounted on the respective
pivot pins of the pawl 158 and 168. Pawl 168 serves as a stop
member for limiting the rotation of the ratchet 159.
On the lower portion of the carrier plate 156 is an extension
carrying a pin 172. Pin 172 extends forwardly a distance sufficient
to engage a depression in a clover-shaped cam 174 which serves to
positively position the elements of the gearbox when the instrument
is in its readiness mode.
With reference to FIG. 32, a main drive gear 176 is shown to be
mounted on the same axis that carries the ratchet 159 and the cam
174. These elements move together and in unison. FIG. 31 shows that
the main drive gear 176 engages two pinion gears 180, the ratio
between the main drive gear 176 and the pinion gears 180 being 6 to
1. In this manner, when the ratchet 159 is turned through the
rotation necessary to move from one tooth to the next, each pinion
gear 180 turns one complete revolution.
Each pinion gear 180 is mounted on a shaft 181 which terminates in
a slot 183. Each slot 183 is adapted to engage a respective
extension 60 integral with each screw 46. In this manner, when the
pinion gear turns through one revolution, the staples are driven
forward one "staple unit."
With particular reference, now, to FIGS. 33 through 35, the
operation of the gearbox will be described. Prior to firing the
skin stapler (FIG. 33), the driving member 28 is in its
rearwardmost position. The plunger 34, with its notch 152, is in
its upper position, biased by the spring 35. Thus, the carrier
plate 156 is in its full clockwise position, pawl 168 being in
engagement with a tooth on the rachet 159. The driving region of
pawl 158 is removed from the nearest tooth on the ratchet 159 to
allow for slight "play" in the plate 156 before the ratchet 159 is
rotated. This allows the pin 172 to disengage from the depression
in the cam 174.
When the driving member 28 moves forward, during a stapling
operation, plunger 34 moves down against the force of the spring
35. During the downward movement of the plunger 34, the carrier
plate 156 rotates in a counter-clockwise direction about its pivot
point 157, pawl 158 rotating the ratchet 159.
In FIG. 34, the elements of the gearbox are shown after the pawl
158 has rotated the ratchet 159 through its maximum angle. This
maximum angle is greater than that needed to advance each staple
one staple unit. Thus, the gearbox elements are overdriven.
In FIG. 35, the gearbox elements are shown in their overdriven
condition, but after the plunger 32 is partially raised due to the
member 28 having moved rearwardly for part of its return
stroke.
The gearbox operation will now be described. In FIG. 33, the gears
are at rest, the member 28 retracted and waiting for an activating
charge. The pin 172 is in engagement with a depression in the cam
174 and thus the ratchet 159, the main gear 176 and the pinion
gears 180 are locked in place. In this position, the slots 183 are
aligned as shown in FIGS. 29 and 30 to allow for the easy insertion
or removal of a staple-carrying cartridge.
When the powering unit is fired, the driving member is thrust
forward and its inclined surface 32 moves plunger 34 downward.
Plunger 34 carries with it plate 156 which rotates in a
counter-clockwise direction.
During the first stage of movement, no gears turn. The play between
pawl 158 and the nearest tooth in the ratchet 159 allows the pin
172 to move out of the depression in cam 174 before gear rotation.
The necessity for this is obvious. Then pawl 158 engages a tooth on
the ratchet 174 and rotates the ratchet, the main gear 176 and the
pinion gears 180 to the positions shown in FIG. 34.
In the position shown in FIG. 34, the gears are over-indexed. That
is, they are driven more than is necessary to move the staples one
staple unit. This is done to ensure that the slots 183 associated
with pinion gears 180 are in proper alignment for insertion or
removal of a cartridge.
After the stapling operation, member 28 moves rearwardly, thus
allowing the plunger 34 to ride upwardly on the incline 32. This
moves the plate 156 and hence the pin 172 into the position shown
in FIG. 35 with the pin 172 moving toward the surface of the cam
174. From this position, the spring 35 urges the pin 172 against
the surface of the cam 174 with the pin coming into contact with
the cam at one of its depressions. Because of the stopping position
of this cam, the action of the pin 172 rotates cam 174 in a
clockwise direction. This rotation continues until the gear
mechanism is in the position shown in FIG. 33, in readiness for
another stapling maneuver.
With reference, now, to FIG. 36, a second embodiment of the main
body portion of the inventive skin stapler will be described. The
main body portion is shown generally at 200 and comprises a region
202 for mounting the cartridge 12 described above with reference to
FIGS. 3 through 13. A cam 204, similar to the cam 22 shown in FIG.
2, is provided. The main body portion 200 has a handle region 206
and a trigger 208. A region 210 serves to house a power unit
identical with that described in FIGS. 23 through 28.
The handle 206 is threaded at the extremity thereof and is fitted
with a plug 214. A pressurized cartridge 216 is filled with a gas
such as carbon dioxide and held in the handle 206, and its charge
is fed to the powering unit 210 by means of a passage 218, which
passage terminates in a chamber 220, similar to the gas inlet port
202 shown in FIG. 23.
The trigger 208 is similar to the triggering mechanism 136 shown in
FIG. 24. Therefore, when the trigger 208 is depressed, the output
shaft of the power unit is moved slightly so as to initiate the
power stroke necessary to drive and form a staple.
When the surgeon uses the instrument 200, all four fingers of one
hand wrap around the handle 206 with the thumb of that hand resting
against trigger 208. The anvil of the staple-carrying cartridge 12
is pressed against the region of the body to be stapled and the
trigger 208 is depressed. The power stroke is initiated, the staple
is formed and the unit is then removed from the stapled area and
moved to the next area where it is desired to position a staple.
The operation is repeated until the incision is completely
sutured.
FIG. 37 is a cross-section viewed in the direction of arrows 37--37
of FIG. 36. From this Figure, it is evident that the passage 218
communicates with the forwardmost bore in the handle 206 at a
position removed from the center thereof. The off-center position
is to ensure that the gas passage is not blocked by any portion of
the gas cartridge or the cartridge-piercing mechanism.
In FIGS. 36 and 37, it can be seen that the handle 206 is fitted
with a bore 222 adapted to house the gas cartridge 216 and a bore
224 serving to mount the cartridge-piercing mechanism described
below. Bores 222 and 224 are communicated by means of a sloped
wall.
As indicated above, it has been found that when gas-powering units
have been used in the past, the pin which serves to pierce the gas
cartridge tends to wear rapidly. As also noted above, it is
contemplated that a loaded and sterilized staple-carrying cartridge
be packaged with a filled and sterilized gas-containing cartridge.
To overcome the drawbacks noted above, a piercing mechanism which
is simple in design and inexpensive in cost is fitted on a gas
cartridge and is adapted to break the seal of the gas cartridge
when same is positioned within the handle 206 of the instrument 200
and screwed into place by means of the plug 214.
With reference, now, to FIGS. 38 and 39, the novel
cartridge-piercing mechanism will be described. A bottle containing
a pressurized gas such as carbon dioxide is shown at 216. The mouth
of the bottle 216 is fitted with a conventional seal 226. A cap 228
is positioned over the mouth of the bottle 216 and an O-ring 230
serves to seal the joint between the bottle 216 and the cap 228.
When packaged and ready for use, a pin shown generally at 232 is
positioned between an inwardly directed flange 234 on the cap 228
and the seal 226 of the bottle 216. The pin 232 comprises a main
body region, a pointed region 238 and an end region 240. The end
region 240 is fitted with a slot 242 extending entirely
thereacross. A passage 246 passes from the extremity of the pin 238
to the extremity of the slot 242.
As seen in FIGS. 36 and 38, when the plug 214 is screwed into the
handle 206, the bottle 216 is urged to move toward the base 244 of
the bore 224. When this takes place, region 240 abuts the base 244
and thus the pointed region 238 of the pin 232 pierces the seal 226
of the bottle 216. Gas from the bottle 216 is thus forced through
the passage 246, out of the slot 242 and into the chamber defined
by the bore 224.
The cap 228 has a thin extension 248 which is flexible and which
comfortably rests against the wall of the core 224. When the
pressurized gas passes into the chamber defined by the bore 224, it
rushes into the region between the main body of the cap 228 and the
extension 248, thus forcing the extension 248 against the wall of
the bore 224. In this manner, the passage of gas is prevented from
backing up into the handle 206.
Above, there have been described specific embodiments of the
present invention. It should be noted, however, that the above
description was given for illustrative purposes only and that many
alterations and modifications may be practiced by those skilled in
the art without departing from the spirit or the scope of the
invention. It is the intent therefore that the present invention
not be limited to the above but be limited only as defined in the
appended claims.
* * * * *