Self-contained powered surgical apparatus

A self-contained powered surgical stapling device is provided which includes an elongate body and a disposable cartridge assembly detachably supported in a distal end portion of the body. The cartridge assembly includes a frame configured to engage the distal end portion of the body, a housing supported within the frame and containing a plurality of surgical fasteners, an anvil mounted for movement with respect to the housing, an actuation assembly configured to translate relative to the housing and the anvil to progressively move the anvil from an open position to a closed position and to sequentially eject the surgical fasteners from the housing to be formed against the anvil, and an axial drive screw mounted in the frame and threadably associated with the actuation assembly for effectuating the longitudinal translation thereof. A motor assembly having an axial drive shaft is disposed within the elongate body, and a coupling is provided for detachably connecting the axial drive shaft and the axial drive screw. A power source is disposed within the elongate body for energizing the motor assembly.

BACKGROUND 
1. Technical Field 
A self-contained powered surgical stapling apparatus is provided for 
sequentially applying a plurality of surgical fasteners to body tissue and 
optionally incising the fastened tissue. 
2. Background of Related Art 
Surgical devices wherein tissue is first grasped or clamped between 
opposing jaw structure and then joined by means of surgical fasteners are 
well known in the art. In some instruments a knife is provided to cut the 
tissue which has been joined by the fasteners. The fasteners are typically 
in the form of surgical staples however, two part polymeric fasteners are 
also utilized. 
Instruments for this purpose can include two elongated members which are 
respectively used to capture or clamp tissue. Typically, one of the 
members carries a disposable cartridge which houses a plurality of staples 
arranged in at least two lateral rows while the other member includes an 
anvil which defines a surface for forming the staple legs as the fasteners 
are driven from the cartridge. Generally, the stapling operation is 
effected by a pusher which travels longitudinally through the cartridge 
carrying member, with the pusher acting upon the staples to sequentially 
eject them from the cartridge. A knife may travel with the pusher between 
the staple rows to longitudinally cut and/or open the stapled tissue 
between the rows of staples. Such instruments are disclosed in U.S. Pat. 
No. 3,079,606 to Bobrov et al. and U.S. Pat. No. 3,490,675 to Green. 
A later stapler disclosed in U.S. Pat. No. 3,499,591 to Green applies a 
double row of staples on each side of the incision. This is accomplished 
by providing a cartridge assembly in which a cam member moves through an 
elongate guide path between two sets of staggered staple carrying grooves. 
Staple drive members are located within the grooves and are positioned in 
such a manner so as to be contacted by the longitudinally moving cam to 
effect ejection of the staples. 
Each of the instruments described above were designed for use in 
conventional surgical procedures wherein surgeons have direct manual 
access to the operative site. However, in endoscopic or laparoscopic 
procedures, surgery is performed through a small incision or through 
narrow a cannula inserted through small entrance wounds in the skin. In 
order to address the specific needs of endoscopic and/or laparoscopic 
surgical procedures, an endoscopic surgical stapling apparatus has been 
developed and is disclosed in U.S. Pat. No. 5,040,715. This apparatus is 
well suited for such procedures and includes a fastener applying assembly 
having an anvil and a staple cartridge provided at the distal end of an 
endoscopic body portion which permits the instrument to be inserted into a 
cannula and be remotely operated by the surgeon through manipulation of a 
proximal handle mechanism. 
The instruments discussed above all require some degree of manually applied 
force in order to clamp, fasten and/or cut tissue. Surgeons have thus 
recognized the benefits of using self-powered instruments that are 
actuable with only a limited degree of physical force. Self-powered 
surgical instruments have been provided to serve these needs and include 
both gas powered surgical staplers, as shown, for example, in U.S. Pat. 
No. 5,312,023, and electrically powered surgical instruments as described 
in U.S. Pat. Nos. 4,635,638 and 5,258,007, and European Pat. Appln. No. 0 
552 050. In general, prior art electrically powered surgical instruments 
have been driven by external power sources. The instruments were connected 
to the power sources by conductive cables. Such cables could, however, 
become entangled during a surgical procedure, thereby complicating the 
operation. 
It would be beneficial to provide a self-contained powered surgical 
apparatus for applying a plurality of surgical staples to body tissue and 
concomitantly incising the stapled tissue. Such an apparatus should be 
compact, lightweight and easy to manufacture. Currently, surgical 
instruments are designed for use in either open, i.e. invasive procedures, 
or endoscopic/laparoscopic procedures. As noted above, endoscopic 
instruments require elongate shafts to access remote surgical sites. 
Conventional surgical instruments are not constructed in this manner. It 
would be advantageous to provide a powered surgical instrument which can 
be readily adapted for use in both conventional and laparoscopic 
procedures. 
SUMMARY 
A self-contained powered surgical apparatus for applying a plurality of 
surgical fasteners to body tissue is provided. The apparatus includes an 
elongate instrument body defining a longitudinal axis, a cartridge 
assembly housing a plurality of surgical fasteners, and an anvil member 
mounted adjacent the cartridge assembly and configured for movement with 
respect thereto between an open and a closed position. 
The apparatus further includes a motor assembly disposed within the 
elongate instrument body, an actuating assembly driven by the motor 
assembly for effectuating progressive closure of the anvil and sequential 
ejection of the surgical fasteners and a power source disposed within the 
body for energizing the motor assembly. Preferably, the actuating assembly 
includes a drive member which is threadably associated with an axial drive 
screw that is driven by the motor assembly. 
In a preferred embodiment, the actuating assembly includes a first camming 
mechanism configured to move the anvil member into a closed position to 
clamp tissue, and a second camming mechanism configured to sequentially 
eject fasteners from the cartridge as it translates therethrough. A tissue 
cutting member is preferably associated with the actuating assembly for 
translating through the cartridge assembly to incise the stapled body 
tissue. A control for the motor assembly to operate the powered surgical 
apparatus preferably includes first and second control buttons for 
effecting distal and proximal movement of the actuating assembly. 
In one embodiment, the powered surgical apparatus includes an elongate 
shaft configured to engage with a proximal end of the main instrument body 
to facilitate utilization of the apparatus during an endoscopic procedure. 
Preferably, the extension shaft interacts with the motor control buttons 
at the proximal end of the main instrument body to operate the apparatus 
from a location remote from the surgical site. 
In another embodiment the powered surgical apparatus is intended to be 
employed during a laparoscopic procedure by providing a mechanical hand 
which is configured to extend into the abdominal cavity through a cannula 
and be remotely manipulated to actuate the apparatus. 
In another embodiment, the powered surgical apparatus includes an elongate 
body defining a longitudinal axis, and a disposable cartridge assembly 
which is detachably supported in a distal end portion of the elongate 
body. 
The disposable cartridge assembly includes a frame having a proximal end 
portion configured to engage the distal end portion of the elongate body, 
and a housing supported within the frame and containing a plurality of 
surgical fasteners. An anvil member is pivotably associated with the frame 
and is mounted for movement with respect to the housing between an open 
position and a closed position. An actuation assembly is disposed within 
the frame and is configured to translate in a longitudinal direction 
relative to the housing and the anvil to progressively move the anvil from 
the open position to the closed position and sequentially eject the 
surgical fasteners from the housing to be formed against the anvil. An 
axial drive screw is rotatably mounted within the frame and threadably 
associated with the actuation assembly for effectuating the longitudinal 
translation thereof 
The surgical apparatus further includes a motor assembly having an axial 
drive shaft, and a coupling to detachably connect the axial drive screw of 
the cartridge assembly to the axial drive shaft of the motor. A power 
source is disposed within the elongate body for energizing the motor 
assembly. Preferably, a bayonet-type fitting is associated with the distal 
end portion of the elongate body and the proximal end portion of the frame 
to facilitate the detachable connection of the cartridge assembly. 
Further features of the powered surgical apparatus will become more readily 
apparent to those skilled in the art from the following detailed 
description of the invention taken in conjunction with the drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In the drawings and in the description which follows, the term "proximal", 
as is traditional, will refer to the end of the apparatus which is closest 
to the operator, while the term "distal" will refer to the end of the 
apparatus which is furthest from the operator. 
The apparatus shall be discussed in terms of both conventional and 
endoscopic procedures. However, use herein of terms such as "endoscopic", 
"endoscopically", and "endoscopic portion", among others, should not be 
construed to limit the present apparatus for use only in conjunction with 
an endoscopic tube. To the contrary, it is believed that the present 
apparatus may find use in procedures wherein access is limited to a small 
incision including but not limited to arthroscopic and/or laparoscopic 
procedures. 
Referring now to the drawings wherein like reference numerals identify 
similar structural elements of the apparatus, there is illustrated in FIG. 
1 a self-contained powered surgical stapler constructed in accordance with 
a preferred embodiment and designated generally by reference numeral 10. 
Referring to FIG. 1, powered surgical apparatus 10 is configured for use as 
a hand-held device for applying a plurality of surgical staples to tubular 
vessels and body tissue during conventional invasive surgical procedures. 
By way of example only, surgical apparatus 10 may have a length measuring 
from about 5.0 inches to about 7.0 inches, and an outer diameter of about 
0.450 inches to about 0.500 inches. Preferably, the length of surgical 
apparatus 10 is between 6.0 inches and 6.5 inches, while the preferred 
diameter is between 0.470 inches and 0.480 inches. Clearly, other 
dimensions are contemplated. In one embodiment, surgical apparatus 10 is 
also adapted for use in endoscopic procedures through remote actuation 
from a location outside the patients body, as shown in FIGS. 2A and 2B. 
This is achieved by providing an elongated extension shaft 12 which 
attaches to the proximal end of surgical apparatus 10 by commonly known 
connective methods such as snap fit. Extension shaft 12 is preferably 
dimensioned and configured for insertion through a cannula or trocar 
device and has a length measuring from about 10.0 inches to about 17.0 
inches. A flexible shaft 12 or rigid shaft 12' can be utilized. 
Referring to FIG. 3, in another embodiment, surgical apparatus 10 is 
intended to be operated by a mechanical hand 15 which is configured to 
extend through trocar device 17 during a laparoscopic surgical procedure. 
Mechanical hand 15 includes four articulated fingers 15a-15d and an 
opposable thumb 15e which are hinged together to enable relative movement 
between a constricted position wherein the forehand and fingers are drawn 
together into a narrowed formation to facilitate their extension through 
trocar 17 and a relaxed position wherein the forehand and fingers are 
deployed into a spread position to perform dexterous tasks such as 
operating surgical apparatus 10 by actuating a switch provided on the 
apparatus. 
Referring to FIG. 4, surgical apparatus 10 includes an elongate body 20 
including complimentary body sections 22 and 24 which define a series of 
internal chambers for housing and supporting various mechanical components 
of apparatus 10. The internal chambers defined within body sections 22 and 
24 include distal chamber 26, medial chamber 28, and proximal chamber 30. 
The components housed within body sections 22 and 24 of surgical apparatus 
10 include an elongate housing channel 32 having a base 34 and opposed 
upstanding channel walls 38a and 38b. Housing channel 32 is maintained 
within the distal chamber 26 of body 20 and is configured to support the 
assembly 40 and the actuating assembly 42. 
The assembly 40 includes an elongate staple cartridge 44 having a plurality 
of transverse slots 46 each configured to support a respective staple 48 
and staple pusher 50. Cartridge 44 is also provided with five spaced apart 
longitudinal slots including a central slot 52 and lateral slot pairs 54a, 
54b and 56a, 56b. The lateral slot pairs 54a, 54b and 56a, 56b serve to 
accommodate longitudinal translation of the elongate camming bars 58a, 58b 
and 60a, 60b of actuating assembly 42 while the central slot 52 serves to 
accommodate longitudinal translation of a cutting blade 62. Actuating 
assembly 42 and the components associated therewith will be described in 
greater detail hereinbelow. 
Assembly 40 further includes an elongate anvil 64 which defines an interior 
fastener forming surface 65 against which staples are driven when ejected 
from cartridge 44 by the actuating assembly 42. A pair of outwardly 
depending wings 66a and 66b are formed adjacent the proximal end of anvil 
64 for engaging a pair of correspondingly positioned reception slots 68a 
and 68b formed in the opposed upstanding channel walls 38a and 38b of 
housing channel 32. The engagement of wings 66a and 66b within slots 68a 
and 68b facilitates pivotal movement of anvil 64 with respect to cartridge 
44. A longitudinal slot 70 extends along a substantial portion of the 
length of anvil 64 to accommodate the longitudinal translation of cutting 
blade 62 and the portion of actuating assembly 42 which supports the 
cutting blade. Similarly, a longitudinal slot 75 is formed in the base 34 
of housing channel 32 (see FIG. 6). The orientation and length of slots 70 
and 75 correspond substantially to that of the central slot 52 provided in 
cartridge 44. 
A spring 65 extends from the proximal end of anvil 64 and is attached to 
body section 22 (or alternatively base 34) to bias the anvil towards the 
cartridge 44. Thus, in use, as tissue is positioned between the anvil and 
cartridge, the anvil is forced away from the cartridge by the tissue. 
Actuation of the actuating assembly (discussed below) forces anvil 64 into 
closer cooperative alignment with cartridge 44 to more firmly and 
progressively clamp the tissue. In an alternate embodiment, the anvil 64 
is biased to an open position, i.e. biased away from cartridge 44, by, for 
example, a pair of springs positioned at a proximal end of the anvil 
between the anvil and cartridge 44. It is also contemplated that the anvil 
can be connected for free movement with respect to the cartridge without a 
spring bias. 
As best seen in FIG. 4, actuating assembly 42 includes two pairs of 
elongate camming bars 58a, 58b and 60a, 60b. The camming bars serve to 
sequentially eject staples 48 from cartridge 44 through interaction with 
staple pushers 50. In particular, each of the elongate camming bars 
includes a distal head portion 72 having an angled camming surface 74. 
Camming surface 74 is configured to contact staple pushers 50 and drive 
the staple pushers in a direction transverse to the longitudinal axis of 
cartridge 44, thereby urging the staples from cartridge 44. An engagement 
notch 76 is formed adjacent the proximal end of each of the camming bars 
for engaging corresponding grooves 78 provided in drive member 80. 
Drive member 80 includes a threaded bore 82 for operatively engaging an 
axial drive screw 84. Drive screw 84 is driven by a motor assembly 86 and 
is connected to the drive shaft 88 of motor assembly 86 by a supporting 
hub assembly which includes an outer support hub 90, an intermediate 
support hub 92, and an inner engagement hub 94 (see FIG. 9). Engagement 
hub 94 is fastened to the proximal end of drive screw 84 and is engaged 
within the intermediate support hub 92. As shown in FIG. 10, drive shaft 
88 is keyed into the opposed end of support hub 92. Support hub 92 is 
coaxially disposed within outer support hub 90 which is maintained with 
the medial chamber 28 of elongate body 20. Motor assembly 86 and the power 
cells 98a-9c which supply energy thereto are maintained with the proximal 
chamber 30 of elongate body 20. A transfer plate 158 is disposed between 
the distal-most power cell 98a and the proximal end of motor assembly 86 
for transferring energy from the power cell to the motor assembly. 
Actuating assembly 42 further includes a camming beam 100 for effectuating 
the progressive closure of anvil 64 to clamp body tissue disposed between 
fastener forming surface 65 of anvil 64 and the tissue contacting surface 
45 of staple cartridge 44. Camming beam 100 includes an upper beam portion 
102, a central web portion 104, and a lower beam portion 106. Central web 
portion 104 supports cutting blade 62. Upper and lower beam extensions 108 
and 109 extend proximally from central web portion 104 to engage drive 
member 80. As shown, the upper and lower beam portions 102, 106 are 
substantially planar. Thus, the mechanism for clamping the anvil (camming 
beam 100) and the mechanism for firing the staples from the cartridge 
(camming bars 58a, 58b and 60a, 60b) are directly connected to drive 
member 80. In use, the upper beam portion 102 of camming beam 100 
progressively contacts the outer surface 67 of anvil 64 to effect 
progressive anvil closure. The central web 104 translates through slots 
52, 70, and 75, and the lower beam portion 106 translates along the outer 
surface 35 of the base 34 of housing channel 32 to maintain anvil closure 
during a stapling procedure. 
Referring to FIG. 8 in conjunction with FIG. 4, a support gate 110 is 
mounted intermediate housing channel 32 which has an aperture 115 for 
supporting the distal end portion of axial drive screw 84. As best seen in 
FIG. 4, support gate 110 includes a pair of opposed winglets 112a and 112b 
for engaging corresponding reception slots 114a and 114b in the opposed 
channel walls 38a and 38b of housing channel 32. Upper and lower grooves 
116 and 118 are formed in support gate 110 to accommodate the translation 
of the upper and lower beam extensions 108 and 109. Lateral slot pairs 
120a, 120b and 122a, 122b are provided in support gate 110 to accommodate 
the translation of camnming bar pairs 58a, 58b and 60a, 60b. 
Surgical apparatus 10 further includes a switching assembly 130 for 
selectively controlling the operation of motor assembly 86. Switching 
assembly 130 includes distal and proximal switch housings 132 and 134, and 
right and left spring biased actuation buttons 136 and 138. A plurality of 
coiled compression springs 135 bias actuation buttons 136 and 138 in a 
proximal direction. Switch housings 132 and 134 are mounted to one another 
and fastened to the proximal end of surgical apparatus 10 by a threaded 
connector 140, and are operatively separated from one another by a distal 
insulating ring 141, a distal contact plate 142, a medial insulating ring 
143, and a proximal contact plate 144. A distal contact ring 145 is 
disposed between distal switch housing 132 and spring 137. 
Distal contact plate 142 includes a pair of opposed upturned contact tabs 
142a and 142b, and proximal contact plate 144 includes a pair of opposed 
upturned contact tabs 144a and 144b which are positioned 60.degree. out of 
phase with tabs 142a and 142b. Each actuation button has associated 
therewith three contact pins, two of which interact with contact plates 
142 and 144 to control the relative movement of drive screw 84. In 
particular, actuation button 136 includes two long pins 146a and 146b and 
one short pin 146c. Short pin 146c is seated within a central reception 
port 147c, while long pins 146a and 146b are seated within lateral 
reception ports 147a and 147b. 
Long pin 146a and short pin 146c are positioned to selectively engage 
contact tabs 142a and 144b respectively, while long pin 146b remains free 
from electrical contact Similarly, actuation button 138 includes long pins 
150a and 150b, and short pin 150c. Short pin 150c is seated within a 
central reception port 151c, while long pins 150a and 150b are seated 
within lateral reception ports 151a and 151b. Long pin 150b and short pin 
150c are positioned to selectively engage contact tabs 142b and 144b 
respectively, while long pin 150a remains free from electrical contact. 
The wiring configuration of switching assembly 130 is illustrated in FIG. 5 
and includes motor line 152 which interconnects the positive terminal 86a 
of motor assembly 86 to contact pins 146a and 150c, and a motor line 154 
which interconnects the negative terminal 86b of motor assembly 86 to 
contact pins 146c and 150b. In addition, a transmission line 156 extends 
between battery transfer plate 158 and contact plate 144, and a 
transmission line 160 interconnects contact plate 142 and contact ring 
145. 
In use, when actuation button 138 is depressed, long pin 150b contacts tab 
142b of distal contact plate 142 and short pin 150c contacts tab 144b of 
proximal contact plate 144. Thus, the positive terminals of power cells 
98a-98c will be connected to the negative terminal 86b of motor assembly 
86 and the negative terminals of power cells 98a-98c will be connected to 
the positive terminal 86a of motor assembly 86, causing drive shaft 88 to 
rotate in a clockwise direction to move drive member 80 distally. When 
actuation button 136 is depressed, long pin 146a contacts tab 142a of 
distal contract plate 142 and short pin 146c contacts tab 144a proximal 
contact plate 144. Thus, the positive terminals of power cells 98a-98c 
will be connected to the positive terminal 86a of motor assembly 86 and 
the negative terminals of power cells 98a-98c will be connected to the 
negative terminal 86b of motor assembly 86, causing drive shaft 88 to 
rotate in a counter-clockwise direction to move the axial drive member 80 
in a proximal direction. It is also envisioned that a single actuator 
button can be provided which will be actuable to operate an axial drive 
screw having a reverse thread formed therein. The reverse thread will 
cause a distally translating drive screw to automatically translate in a 
proximal direction at the conclusion of a fastener forming stroke. 
As discussed briefly hereinabove, surgical apparatus 10 is preferably 
designed for insertion through a trocar or cannula device to apply 
surgical staples to body tissue located within a body cavity while being 
actuable remote from the surgical site. Shaft 12 includes elongate 
transmission members 12a and 12b (or 12a' and 12b') for effectuating 
remote actuation of switching assembly 130 (see FIGS. 2A and 2B). 
Transmission members 12a and 12b (or 12a' and 12b') may include a pair of 
substantially rigid rods for transmitting a mechanical signal to actuation 
buttons 136 and 138, or, in the alternative, the transmission members may 
include transmission cables for directing an electrical signal to 
switching assembly 130. In either instance, the shaft would include two 
actuation buttons to respectively actuate buttons 136 and 138 and cause 
the rotation of drive screw 84 in opposed directions. 
Referring now to FIGS. 6 and 7, prior to operating the surgical stapling 
device 10, the anvil 64 is disposed in a free-movement position to 
facilitate the capture of body tissue (or spring biased to a closed or an 
open position as in the aforementioned alternate embodiments). Movement of 
anvil 64 is accommodated by the pivotal engagement of anvil wings 66a and 
66b in reception slots 68a and 68b. The pivotal movement of anvil 64 is 
best seen in FIG. 6. Prior to actuation, camming beam 100 is maintained 
within a support seat 26a defined in the distal chamber 26 of instrument 
body 20. At such a time, the upper beam portion 102 is out of contact with 
the outer surface 67 of anvil 64 permitting the pivotal movement thereof. 
Also at this time, the distal head portion 72 of each of the camming bars 
58a, 58b and 60a, 60b is disposed proximal to and out of contact with the 
proximal-most staple pushers 50 in cartridge 44. 
Upon actuation, i.e. when actuation button 136 is depressed, motor assembly 
86 is energized and drive shaft 88 rotates axial drive screw 84, causing 
drive member 80 to translate in a distal direction. As best seen in FIG. 
11, as drive member 80 translates distally, the upper beam portion 102 of 
camming beam 100 progressively urges anvil 64 toward cartridge 44 to clamp 
body tissue 165 therebetween. Concomitantly, the camming surface 74 on the 
distal head portion 72 of each of the camming bars of actuation assembly 
42 interacts with staple pushers 50 to sequentially eject surgical staples 
48 from cartridge 44. 
Staples ejected from cartridge 44 are driven through body tissue 165 and 
formed against the inner fastener forming surface 65 of anvil 64. As the 
rows of staples are placed in body tissue 165, cutting blade 62, which 
travels behind the distal head portion 72 of each of the camming bars of 
actuation assembly 42, cuts the stapled body tissue, forming an incision 
between the staple rows. 
Continued actuation of motor assembly 86 effects distal translation of 
drive member 80 until the drive member contacts support gate 110. At such 
a time, camming beam 100 is disposed at the distal end of fastener 
applying assembly 40 and the distal head 70 of each of the camming bars is 
disposed within the distal portion 45 of staple cartridge 44. Following 
the stapling operation, depression of actuation button 138 causes drive 
member 80 to translate proximally, drawing therewith camming beam 100 and 
camming bars 58a, 58b and 60a, 60b to their proximal-most position (FIG. 
6). 
It is also contemplated that the staple cartridge 44 can be removable so 
that once actuation assembly 42 has returned to its proximal-most position 
after firing the fasteners, staple cartridge 44 can be removed and 
replaced with a loaded staple cartridge and actuation button 136 can be 
depressed again to fire the stapling apparatus. 
Referring now to FIG. 13, there is illustrated another self-contained 
powered surgical apparatus constructed in accordance with a preferred 
embodiment of the subject application and designated generally by 
reference numeral 200. Surgical apparatus 200 is configured to 
sequentially apply a plurality of surgical fasteners to body tissue during 
conventional and/or endoscopic surgical procedures. In brief, surgical 
apparatus 200 includes an elongate instrument body 210 and a disposable 
cartridge assembly 220 which is detachably connected to a distal end 
portion of the instrument body 210 by a bayonette-type coupling 
arrangement. Instrument body 210 houses a motor assembly 212 and a 
plurality of power cells or batteries 214 for energizing the motor 
assembly. The power cells can be lithium, alkaline or nickel-cadmium 
batteries. An insulating material is wrapped around the power cells to 
isolate them from conductive outer casing 215. A conductive contact plate 
216 is disposed between the terminal end 212a of motor assembly 212 and 
the distal-most battery 214a, and a coiled spring 218 is disposed within 
the proximal end of instrument body 210 to bias the batteries distally 
(see FIG. 17). 
Referring to FIGS. 13 and 14, cartridge assembly 220 includes a frame 222 
having an adapter 224 configured to detachably engage a distal end portion 
of instrument body 210 (see generally FIG. 16), and a housing channel 226 
configured to retain a cartridge 228 containing a plurality of surgical 
fasteners 230. Cartridge assembly 220 further includes an anvil 232 which 
is pivotably mounted to housing channel 226, and an actuation assembly 
designated generally by reference numeral 240 which is driven by motor 
assembly 212 and configured to eject the surgical fasteners 230 from 
cartridge 228, and concomitantly move anvil 232 between an open position 
and a closed position (see generally FIGS. 18 and 19). 
With continuing reference to FIG. 14, adapter 224 includes an elongate 
distal portion 234 and a proximal mounting portion 236 dimensioned and 
configured for reception within the distal end of instrument body 210. 
Housing channel 226 includes opposed side walls 226a and 226b, and a floor 
226c. An aperture 238 is defined in floor 226c adjacent the proximal end 
of housing channel 226 for receiving a threaded fastener 242 which mounts 
the housing channel 226 to the adapter 224. A pair of opposed apertures 
244a and 244b are defined in the side walls 226a and 226b of housing 
channel 226 for receiving a pair of outwardly extending flanges 232a and 
232b which are formed adjacent the proximal end of anvil 232 and about 
which anvil 232 pivots between closed and opened positions to capture and 
release body tissue. A pair of spring members 246a and 246b are disposed 
within apertures 244a and 244b for biasing anvil 232 into an open 
position. Opposed engagement notches 248a and 248b are also defined in the 
opposed side walls 226a and 226b of housing channel 226 for receiving a 
pair of corresponding detents formed on cartridge 228, i.e. detent 228b. 
The detents are formed monolithically with the fastener retaining 
cartridge 228 and secure the cartridge within the distal portion of 
housing channel 226. 
With continuing reference to FIG. 14, the actuation assembly 240 of 
cartridge assembly 220 includes an actuation sled 250 configured to 
translate through cartridge 228 to effectuate the ejection of surgical 
fasteners therefrom. Sled 250 includes a plurality of spaced apart 
upstanding cam plates 252 each having an angled leading edge 254 for 
sequentially engaging a plurality of staple drivers 256 which drive 
surgical fasteners 230 from cartridge 228. Actuation sled 250 is driven 
through cartridge 228 by an actuation beam 260 and an axial drive screw 
270. Actuation beam 260 has a pair of parallel elongate beam extensions 
262 and 264 the proximal ends of which are mounted to a follower housing 
266. Follower housing 266 supports a drive nut 268 which is threadably 
associated with axial drive screw 270. Follower housing 266 is mounted 
within frame 222 in such a manner so that axial rotation of drive screw 
270 causes the longitudinal translation thereof. The distal end 270a of 
drive screw 270 is rotatably supported in a stationary support mount 272 
which is maintained within frame 222 and engaged in a slotted region 235 
of the distal portion of adapter 234. Support mount 272 also serves to 
guide the longitudinal translation of beam extensions 262 and 264 as 
actuation beam 260 is driven in a longitudinal direction by follower 
housing 266. A knife blade 265 is mounted adjacent the leading edge of 
actuation beam 260 for cutting body tissue as actuator 250 translates 
through cartridge 228. 
Referring to FIGS. 14-16, the proximal end 270b of drive screw 270 is 
configured to engage a screw coupling 274. Screw coupling 274 is rotatably 
supported within an axial bore 276 defined in the proximal mounting 
portion 236 of adapter 224 and is detachably connected at a proximal end 
to a shaft coupling 278 which is supported on the drive shaft 280 of motor 
assembly 212. The cooperative engagement of the two couplings will be 
discussed in greater detail hereinbelow. 
Referring once again to FIG. 14, the distal end of actuation beam 260 
include a retention flange 282 for supporting a generally cylindrical cam 
roller 284 and an engagement slot 286 for retaining a substantially planar 
cam beam 288. Cam roller 284 engages and translates relative to an upper 
camming surface 290 of anvil 232 to effectuate the progressive closure 
thereof as follower housing 266 and actuation beam 260 translate through 
housing channel 226 to fire surgical fasteners 230 from cartridge 228. Cam 
beam 288 engages and translates relative to the outer surface of the floor 
226c of housing channel 226 to balance the forces exerted upon anvil 232 
by cam roller 284 during closure. A longitudinal slot 292 is defined in 
the floor 226c of housing channel 226 and a corresponding longitudinal 
slot 294 is defined in the anvil 232 to accommodate the longitudinal 
translation of actuation beam 260. A transverse slot extension 296 is 
defined at the distal end of anvil slot 294 to receive cam roller 284 at 
the end of its translation, and thereby permit anvil 232 to return to an 
open position under the bias of spring members 246a and 246b following a 
fastening operation. Thus, body tissue is automatically unclamped as soon 
as all of the fasteners have been fired. 
Referring now to FIGS. 13 and 16, as noted hereinabove, the cartridge 
assembly 220 of surgical apparatus 200 is configured as a separate unit 
which is detachably mounted to the distal end of the instrument body 210 
by a bayonette-type coupling arrangement. The bayonette coupling 
arrangement includes a pair of generally J-shaped slots 304 defined 
adjacent the distal end of instrument body 210, and a pair of 
corresponding engagement pins 312 and 314 mounted in the proximal mounting 
portion 234 of adaptor 224 (see also FIG. 14). During attachment of 
cartridge assembly 220, the proximal mounting portion 236 of adapter 224 
is axially rotated approximately 20 degrees to engage pins 312 and 314 in 
corresponding slots 302, 304. 
Referring to FIGS. 16 and 17, a coiled compression spring 316 is supported 
on the drive shaft 280 of motor assembly 212 for biasing the shaft 
coupling 278 in a distal direction. Shaft coupling 278 is supported within 
a stepped axial bore 318 defined in instrument body 210 and includes a 
transverse slot 320 which is dimensioned and configured to engage a 
corresponding teeth 322 formed at the proximal end of screw coupling 274. 
The function of coupling spring 316 is two fold. Firstly, if teeth 322 and 
flange 322 are not aligned when the proximal mounting portion of adapter 
224 is inserted into the distal end of instrument body 210, coupling 
spring 316 will compensate for the misalignment and facilitate engagement 
of the couplings upon initial rotation of drive shaft 280. More 
particularly, upon insertion of the adapter, if misaligned, teeth 322 will 
abut the distal-most surface of shaft coupling 278. When drive shaft 280 
initially rotates and slot 320 aligns with flange 322, coupling spring 316 
will decompress and force shaft coupling 278 in a distal direction to 
cause the two couplings to detachably engage. The second function of 
coupling spring 316 is to bias adapter 224 in a distal direction when the 
bayonette coupling which detachably maintains cartridge assembly 220 in 
body portion 210 is engaged. 
Referring to FIGS. 15-17, a switch 330 is provided for selectively 
controlling the operation of motor assembly 212. Switch 330 is a 
touch-sensitive contact switch that is wrapped around the circumference of 
instrument body 210 within a recessed area 332. Switch 330 includes an 
outer contact layer 330a, a medial insulating layer 330b, and an inner 
conductive layer 330c. A slot 333 is provided in insulating layer 330b to 
permit contact between the outer contact layer 330a and the inner 
conductive layer 330c. A motor control circuit is defined by a first 
electrically conductive metallic strip 334 which connects switch 330 to 
the conductive outer casing 215 of instrument body 210, a second 
conductive strip 235 which connects outer casing 215 to the terminal T of 
the proximal-most power cell 214d, and a third conductive strip 336 which 
connects switch 330 to the terminal end 212a of motor assembly 212. 
Referring now to FIGS. 18 and 19, in operation, when surgical apparatus 200 
is introduced into a surgical site, body tissue is captured between anvil 
232 and cartridge 228. A radially inwardly directed force in two locations 
on switch 330 brings outer layer 330a into contact with inner layer 330c, 
then causing current to flow to motor assembly 212 to rotate the drive 
shaft 280 of motor assembly 212. The rotational motion of drive shaft 280 
is transferred to drive screw 270 through couplings 274 and 278. Axial 
rotation of drive screw 270 causes corresponding longitudinal translation 
of follower housing 266 and actuation beam 260. 
As actuation beam 260 translates distally, cam roller 284 progressively 
moves anvil 232 from the normally biased open position shown in FIG. 18 to 
the closed position illustrated in FIG. 19. Concomitantly, actuation sled 
250 is driven from the proximal position illustrated in FIG. 18, through 
fastener retention cartridge 228, to the distal-most position shown in 
FIG. 19 sequentially engaging staple drivers 256 so as to drive surgical 
fasteners 230 through body tissue 350. At the same time, knife blade 265 
trails actuation sled 250 to form an incision in the stapled body tissue 
350. When cam roller 284 reaches the distal end of longitudinal slot 294, 
it drops into transverse slot extension 296, permitting anvil 232 to 
return to an open position and release the stapled body tissue 350. At the 
conclusion of the fastener applying operation, cartridge assembly 212 is 
manipulated in such a manner so as to disengage pins 312 and 314 from 
slots 302 and 304, and detach the cartridge adapter 224 from the distal 
end of instrument body 210. Thereafter, the cartridge assembly may be 
discarded and a new cartridge assembly may be detachably mounted to 
instrument body 210. 
Although the apparatus has been described with respect to preferred 
embodiments, it will be readily apparent to those having ordinary skill in 
the art to which it appertains that changes and modifications may be made 
thereto without departing from the spirit or scope of the appended claims.