[19]
`United States Patent
`5,941,442
`[11] Patent Number:
`[45] Date of Patent: *Aug. 24, 1999
`Geiste et al.
`
`
`
`U8005941442A
`
`[54]
`
`[75]
`
`SURGICAL STAPLER
`
`Inventors: Robert J. Geiste, Milford; Mitchell J.
`Palmer, New Milford; Lisa W. Heat0n,
`Norwalk; Robert C. Savage, Stratford;
`Jon Wilson, Fairfield, all of Conn.
`
`[73]
`
`Assignee: United States Surgical, Norwalk,
`Conn.
`
`Notice:
`
`This patent is subject to a terminal dis-
`claimer.
`
`Appl. No.: 08/549,580
`
`Filed:
`
`Oct. 27, 1995
`
`Int. Cl.6 ................................................... A61B 17/068
`.. 227/175.1; 227/19; 227/176.1;
`US. Cl.
`
`227/180.1
`Field of Search .................................... 227/19, 175.1,
`227/176.1, 180.1, 179.1
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`.
`
`.
`1/1994 Fox et a1.
`Re. 34,519
`3/1963 Bobrov et a1.
`3,079,606
`1/1970 Green et a1.
`.
`3,490,675
`3/1970 Green .
`3,499,591
`12/1977 Meredith.
`4,064,881
`9/1978 Vishnevsky .
`4,111,206
`5/1983 Green .
`4,383,634
`7/1983 Moshofsky .
`4,391,401
`2/1984 Green .
`4,429,695
`6/1985 Green .
`4,520,817
`4,556,058 12/1985 Green .
`.
`4,592,498
`6/1986 Braun et a1.
`.
`4,606,343
`8/1986 Conta et a1.
`4,608,981
`9/1986 Rothfuss et a1.
`4,610,383
`9/1986 Rothfuss et a1.
`4,633,861
`1/1987 Chow et a1.
`.
`4,633,874
`1/1987 Chow et a1.
`.
`4,664,305
`5/1987 Blake, III et a1.
`4,767,044
`8/1988 Green .
`4,821,942
`4/1989 Richards et a1.
`4,863,088
`9/1989 Redmond et a1.
`
`.
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`......................... 227/180.1
`
`.
`
`.
`7/1990 Oddsen et a1.
`4,944,443
`9/1990 Tompkins et a1.
`4,955,959
`12/1990 Green .
`4,978,049
`7/1991 Tompkins et a1.
`5,031,814
`8/1991 Green et a1.
`.
`5,040,715
`11/1991 Schulze et a1.
`5,065,929
`.
`1/1992 Foslien et a1.
`5,083,695
`4/1992 Tompkins et a1.
`5,106,008
`8/1992 Foslien et a1.
`.
`5,141,144
`5,156,614 10/1992 Green et a1.
`.
`5,326,013
`7/1994 Green et a1.
`.
`5,352,238 10/1994 Green et a1.
`5,366,133
`11/1994 Geiste .
`5,415,334
`5/1995 Williamson, IV et a1.
`5,415,335
`5/1995 Knodell, Jr.
`.
`5,445,304
`8/1995 Plyley et al.
`5,447,265
`9/1995 Vidal et al.
`5,470,006
`11/1995 Rodak .
`5,478,003
`12/1995 Green et a1.
`5,485,952
`1/1996 Fontayne .
`...................... 227/180.1
`5,752,644
`5/1998 Bolanos et a1.
`FOREIGN PATENT DOCUMENTS
`
`.............................. 227/19
`.......................... 227/176.1
`
`......................... 227/176.1
`
`0365153
`
`8/1995 European Pat. Off.
`
`.
`
`Primary Examiner—Scott A. Smith
`
`[57]
`
`ABSTRACT
`
`A surgical stapler is disclosed which includes a first body
`portion supporting an anvil plate defining a fastener forming
`surface, and a second body portion configured to releasably
`mate with the first body portion. A disposable loading unit
`is removably supported in the second body portion and
`includes a cartridge defining a plurality of slots, a plurality
`of surgical fasteners disposed in the slots, a plurality of
`ejectors positioned adjacent the surgical fasteners, and a
`wedged actuator configured to enter into and translate
`through the cartridge to sequentially interact with the ejec-
`tors. An elongated actuation member is mounted for longi-
`tudinal movement within the second body portion and is
`releasably engagable with the wedged actuator, whereby
`longitudinal movement of the actuation member causes the
`wedged actuator to interact with the ejectors, driving the
`surgical fasteners from the cartridge to be formed against the
`anvil plate.
`
`21 Claims, 14 Drawing Sheets
`
`IS 1010
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` 1
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`IS 1010
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`1
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`US. Patent
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`Aug. 24, 1999
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`Sheet 1 0f 14
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`5,941,442
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`US. Patent
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`Aug. 24, 1999
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`Sheet 2 0f 14
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`5,941,442
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`US. Patent
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`Aug. 24, 1999
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`Sheet 3 0f 14
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`US. Patent
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`Aug. 24, 1999
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`Sheet 4 0f 14
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`14
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`5
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`US. Patent
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`Aug. 24, 1999
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`Sheet 5 0f 14
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`US. Patent
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`Aug. 24, 1999
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`Sheet 6 0f 14
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`5,941,442
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`US. Patent
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`Sheet 7 0f 14
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`US. Patent
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`Aug. 24, 1999
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`US. Patent
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`Aug. 24, 1999
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`Sheet 9 0f 14
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`US. Patent
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`Aug. 24, 1999
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`Sheet 10 0f 14
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`US. Patent
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`Aug. 24, 1999
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`Sheet 11 0f 14
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`5,941,442
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`US. Patent
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`Aug. 24, 1999
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`5,941,442
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`Aug. 24, 1999
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`Aug. 24, 1999
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`5,941,442
`
`1
`SURGICAL STAPLER
`
`BACKGROUND
`
`1. Technical Field
`
`This application relates to surgical staplers, and more
`particularly,
`to an apparatus for sequentially applying a
`plurality of surgical fasteners to body 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 instru-
`ments 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 fas-
`teners are also utilized
`
`Instruments for this purpose can comprise two elongated
`members which are respectively used to capture or clamp
`tissue. Typically, one of the members carries a cartridge
`which houses a plurality of staples arranged in at least two
`lateral rows while the other member comprises an anvil
`which defines a surface for forming the staple legs as the
`fasteners are driven from the cartridge. Where two part
`fasteners are used, this member carries the mating part, e.g.
`the receiver,
`to the fasteners 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 sequen-
`tially eject them from the cartridge. Aknife 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 US. Pat. No. 3,079,606
`and US. Pat. No. 3,490,675.
`A later stapler disclosed in US. Pat. No. 3,499,591
`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.
`Other examples of staplers are disclosed in US. Pat. Nos.
`4,429,695, 5,065,929, and 5,156,614.
`Many of the prior art linear stapling devices discussed
`above include a significant number of moving parts, small
`components and machined structural elements that are costly
`to fabricate and time consuming to assemble. These factors
`add to the overall cost of the stapling devices and thus
`increase the costs incurred by hospitals and health care
`professionals, and ultimately,
`the patient upon which the
`devices are utilized. A linear stapler that could be manufac-
`tured and assembled less expensively would provide great
`benefits.
`
`SUMMARY
`
`The subject application is directed to a linear surgical
`stapler that is constructed from fewer, less expensive com-
`ponents than known prior art staplers configured to sequen-
`tially apply a plurality of surgical staples to body tissue. The
`stapler includes a first body portion supporting an anvil plate
`which defines a fastener forming surface and a second body
`portion configured to releasably mate with the first body
`portion. In the detailed description which follows, the first
`and second body portions of the stapler are also referred to
`as the “anvil half-section” and “cartridge half-section”,
`respectively.
`
`10
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`2
`A disposable loading unit is removably supported in the
`second body portion and includes a cartridge defining a
`plurality of slots and a tissue contacting surface, a plurality
`of surgical fasteners disposed in the slots of the cartridge, a
`plurality of ejectors or pushers positioned adjacent
`the
`surgical fasteners. A wedged actuator provided in the dis-
`posable loading unit is positioned and configured to enter
`and translate through the cartridge to sequentially interact
`with the pushers.
`The stapler in a preferred embodiment, further includes an
`elongated actuation member mounted for
`longitudinal
`movement within the second body portion and releasably
`engagable with the wedged actuator, whereby longitudinal
`movement of the actuation member causes the wedged
`actuator to interact with the ejectors, driving the surgical
`fasteners from the cartridge to be formed against the anvil
`plate.
`The first body portion preferably includes an elongate
`anvil support member and a pivoting lever handle. The anvil
`plate is preferably formed separate from the anvil support
`member and includes a plurality of staple forming pockets
`defining the anvil forming surface. The anvil plate also
`includes means for engaging the anvil support member
`during assembly of the surgical stapler to securely fasten the
`anvil plate to the support member. A notched area is defined
`adjacent a proximal end of the anvil support member and
`correspondingly positioned detents are formed adjacent a
`proximal end of the second body portion. The notched area
`and the detents cooperate to facilitate relative pivotal move-
`ment of the first and second body portions when they are
`mated with one another.
`
`Preferably, a pair of upstanding flanges are formed on the
`disposable loading unit proximal of the tissue contacting
`surface thereof. The flanges define a structural tissue stop to
`limit the movement of body tissue. The flanges are also
`dimensioned to engage a pair of corresponding apertures
`formed in the anvil plate to maintain the first and second
`body portions in alignment with one another when the
`surgical stapler is in a closed or clamped position.
`The wedged actuator of the disposable loading unit is
`preferably monolithically formed from a planar piece of
`sheet metal during a stamping process and includes a planar
`base and a pair of upstanding parallel cam wedges. An
`upturned flange is formed at a distal end of the actuation
`member for releasably engaging a complementary slot
`formed in the base of the wedged actuator. The wedged
`actuator preferably further includes an upstanding support
`flange to which a knife blade is fastened. The knife blade is
`provided to form an incision in the stapled body tissue.
`A retaining channel depends from a distal end of the
`second body portion for supporting the disposable loading
`unit. Preferably, the disposable loading unit and the retaining
`channel include complementary engagement structures for
`releasably securing the disposable loading unit in the retain-
`ing channel. Opposed bearing structures are formed in the
`retaining channel at a proximal end thereof for abutting the
`anvil support beam when body tissue is clamped between
`the anvil plate and the tissue contacting surface of the
`cartridge. The bearing structures serve to inhibit the anvil
`support beam from bending as a result of the compressive
`forces generated during clamping.
`Further features of the surgical apparatus of the subject
`application will become more readily apparent
`to those
`skilled in the art from the following detailed description of
`the apparatus taken in conjunction with the drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Various embodiments of the surgical stapling apparatus of
`the subject application will be described hereinbelow with
`reference to the drawings wherein:
`16
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`5,941,442
`
`3
`FIG. 1A is a perspective view of a surgical stapling
`apparatus constructed in accordance with a preferred
`embodiment with the clamping handle thereof disposed in
`an upright open position;
`FIG. 1B is a perspective view of the surgical stapling
`apparatus illustrated in FIG. 1A with the clamping handle
`disposed in a closed position;
`FIG. 2 is an exploded perspective view of the surgical
`stapling apparatus of FIGS. 1A and 1B;
`FIG. 3 is a perspective view of the lower body portion of
`the surgical stapling apparatus of FIGS. 1A and 1B;
`FIG. 4A is a top plan view of the retention channel of the
`surgical stapling apparatus of FIGS. 1A and 1B;
`FIG. 4B is a side elevational view of the retention channel
`shown in FIG. 4A;
`FIG. 4C is a perspective view of the retention channel of
`FIGS. 4A and 4B with the disposable loading unit retained
`therein;
`FIG. 5 is an enlarged perspective view, with parts sepa-
`rated for ease of illustration, of the disposable loading unit
`and actuation assembly of the surgical stapling apparatus of
`the subject application;
`FIG. 5A is a cross-sectional view showing the engage-
`ment of the cartridge lip and the retention channel;
`FIG. 6A is a perspective view of the actuation sled of the
`disposable loading unit shown in FIG. 5 in a pre-formed
`condition;
`FIG. 6B is a perspective view of the actuation sled shown
`in FIG. 6A in a formed condition with the knife blade
`
`separated therefrom for illustrative purposes;
`FIG. 6C is a perspective view of the formed actuation sled
`shown in FIG. 6B with the knife blade mounted to the blade
`
`support portion thereof;
`FIG. 7 is a plan view of the preformed anvil plate which
`is mounted to the anvil support beam of the upper body
`portion of the stapling apparatus shown in FIGS. 1A and 1B;
`FIG. 8 is a cross-sectional view of the preformed anvil
`plate taken along line 8—8 of FIG. 7;
`FIG. 9 is a front end view of the preformed anvil plate
`illustrated in FIGS. 7 and 8;
`FIG. 10 is a perspective view of the upper body portion
`of the surgical stapling apparatus of FIGS. 1A and 1B with
`an enlarged localized view of a distal portion thereof illus-
`trating the connective engagement between the anvil plate
`and the anvil support beam;
`FIG. 11 is an exploded perspective view of an embodi-
`ment utilizing a lockout mechanism to prevent reactuation of
`the apparatus;
`FIG. 11A is an enlarged cross-sectional view of the
`T-shaped member of the lockout mechanism;
`FIG. 12 is an enlarged perspective view of the actuation
`channel having an edge for engagement by the hook of the
`lockout mechanism;
`FIGS. 13 and 13A are side views of the lockout mecha-
`
`nism illustrating its movement from a non-engaged to an
`engaged position;
`FIG. 14 is a side elevational view in cross-section of the
`
`surgical stapling apparatus of the subject application with
`the actuation sled disposed in a pre-actuated proximal posi-
`tion;
`FIG. 15 is a side elevational view in cross-section of the
`
`surgical stapling apparatus of the subject application with
`the actuation sled disposed in a partially advanced position;
`and
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`60
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`65
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`4
`FIG. 16 is a side elevational view in cross-section of the
`surgical stapling apparatus of the subject application with
`the actuation sled advanced to the distal end of the cartridge
`at the conclusion of a staple firing procedure.
`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 closer to the operator, while the term
`“distal” will refer to the end of the apparatus which is further
`from the operator.
`Referring now to the drawings wherein like reference
`numerals identify similar structural elements, there is illus-
`trated in FIGS. 1A and 1B a surgical stapling device
`constructed in accordance with a preferred embodiment and
`designated generally by reference numeral 10 which
`includes a cartridge half section 11A and an anvil half
`section 11B. As will become readily apparent
`to those
`having ordinary skill
`in the art, surgical stapler 10 is
`constructed in such a manner so as to substantially reduce
`the costs associated with its fabrication and assembly as
`compared to prior art linear staplers.
`Referring to FIGS. 2 and 3, surgical stapler 10 includes a
`body portion 12 defining a handle for grasping and support-
`ing the device. A retaining channel 14 is mounted in the
`interior cavity 15 of body portion 12 adjacent the distal end
`thereof. Retaining channel 14 is dimensioned and configured
`to support a disposable loading unit 20, as illustrated in FIG.
`4C.
`
`the disposable loading unit 20
`As shown in FIG. 5,
`includes a cartridge 22 having a plurality of slots which
`support a corresponding number of surgical staples 24, a
`plurality of staple pushers or ejectors 26 adapted and con-
`figured to eject the staples from the slots when acted upon
`by a staple driving force, and an actuation sled 28 which is
`mounted to translate through cartridge 22 in a longitudinal
`direction to transmit a staple driving force to the ejectors.
`The cartridge is preferably composed of liquid crystal poly-
`mer material; although other materials are contemplated.
`The cartridge 22 has a lip 23 which engages the retention
`channel 14 to prevent inward rotation of the cartridge (see
`FIG. 5A).
`As best seen in FIG. 6A, actuation sled 28 is preferably
`monolithically formed from a single piece of sheet metal or
`a similar material which is folded into the desired structural
`
`In this configuration,
`configuration shown in FIG. 6C.
`actuation sled (staple actuator) 28 defines a base portion 30,
`two upstanding cam wedges 32 and 34, and an upstanding
`shank 35 which supports a knife blade 36. Knife blade 36 is
`preferably spot welded to shank 35, although other known
`fastening methods may be employed. As illustrated in FIG.
`6B, a weldment port 37 and a winglet 39 are provided to
`facilitate the proper alignment and cohesion of knife blade
`36 to shank 35 during fabrication. Cam wedges 32 and 34
`are staggered with respect to one another so that one leads
`the other throughout the sled’s translation through cartridge
`22. In doing so, the staple driving forces within cartridge 22
`remain balanced during a staple driving operation. Longi-
`tudinal slots 22a and 22b accommodate the longitudinal
`translation of cam wedges 32 and 34, while slot 22C accom-
`modates the longitudinal translation of shank 35 (see FIG.
`5). Although illustrated with a knife, it is also contemplated
`that the apparatus can be provided without a knife blade and
`therefore would staple tissue without making an incision.
`The base portion 30 of actuation sled 28 has a transverse
`slot 40 defined therein which is dimensioned and configured
`17
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`17
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`

`

`5,941,442
`
`5
`to releasably retain an upturned flange 42 formed at the
`distal end of elongated actuation channel 44 (FIG. 5). When
`the disposable loading unit 20 is placed into retaining
`channel 14 and actuation sled 28 is disposed in its proximal-
`most position, flange 42 releasably engages slot 40. Thus,
`movement of actuation channel 44 moves actuation sled 28.
`After a stapling operation, when the disposable loading unit
`is removed from the retaining channel, flange 42 is easily
`disengaged from slot 40.
`With continued reference to FIG. 5, actuation channel 44
`is defined by a base portion 45 and two parallel upstanding
`beams 46 and 48 of elongate configuration. The distal ends
`of beams 46 and 48 are staggered to match the staggered
`orientation of cam wedges 32 and 34, respectively. The
`proximal end of each beam projects rearwardly to engage
`the mounting block 49 that is associated with firing knob 50.
`A pair of slots 52 (only one of which is shown) are formed
`in mounting block 49 for receiving the proximal end of each
`of the upstanding beams 46, 48 of actuation channel 44 and
`the slots are provided with detents 54 for engaging apertures
`56 in the beam ends to lockingly retain the beams in
`mounting block 49. In use, longitudinal movement of firing
`knob 50 causes corresponding longitudinal translation of
`actuation channel 44 and actuation sled 28.
`
`retention channel 14
`Referring to FIGS. 2 and 4C,
`includes a base portion 60 and two upstanding parallel walls
`62 and 64. Numerical indicia is imprinted on the walls 62,
`64 of retention channel 14 to indicate the length of the staple
`line. Retention structures are provided at the distal end of
`each of the walls 62, 64 to engage corresponding structures
`provided on the disposable loading unit 20. In particular,
`notches 66a and 66b are provided for engaging correspond-
`ing protuberances, such as protuberance 67, and slots 68a
`and 68b are provided for engaging corresponding detents,
`such as detent 69. These structures inhibit lateral, longitu-
`dinal and perpendicular shifting of the cartridge 22 (and
`disposable loading unit 20) within the retaining channel 14.
`Ramped engagement slots 70a and 70b are also defined in
`the opposed walls of retention channel 14 for interacting
`with a pair of opposed protuberances 72a and 72b (FIG. 5)
`to guide the disposable loading unit 20 into retention chan-
`nel 14 when loaded into surgical stapler 10.
`Referring again to FIG. 2, surgical stapler 10 further
`includes an elongate anvil support beam 80 which has a
`generally U-shaped cross-sectional configuration. Anvil
`support beam 80 and its associated structures are also
`referred to herein as the “anvil half-section”. The distal end
`
`portion 88 of the anvil support beam 80 in one embodiment
`is tapered in height h in a distal direction to provide
`additional support and reduce deflection during a staple
`firing operation. The proximal end portion 82 of support
`beam 80 has a notched area 84 for engaging a pair of
`corresponding detents 86 (only one of which is shown),
`which extend into the cavity 15 of body portion 12 adjacent
`the proximal end thereof The detents 86 are engaged when
`the cartridge half-section 11a and anvil half-section 11b are
`mated with one another. The distal end portion 88 of anvil
`support beam 80 is configured to support a preformed anvil
`plate 90 against which staples are driven and formed during
`a stapling procedure.
`Referring to FIGS. 7 and 8, anvil plate 90 is formed from
`a unitary piece of metal and is cold formed and stamped to
`define a plurality of staple forming recess or cups 91. Each
`staple forming recess corresponds to a particular staple
`housed within cartridge 22. Anvil plate 90, as shown in FIG.
`2, is provided with two opposed tangs 92a and 92b which
`extend inwardly to engage complementary engagement slots
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`93b (only one is shown) in anvil support beam 80 during
`fabrication and assembly (see FIG. 10). The cross-sectional
`configuration of anvil plate 90 is dimensioned to comple-
`ment the cross-sectional geometry of support beam 80 (see
`FIG. 9). More particularly,
`the cavity 97 which extends
`along the length of the anvil plate 90 corresponds to a similar
`channel formed in support beam 80. These areas accommo-
`date shank 35 and knife blade 36 as it translates distally to
`form an incision in stapled body tissue during a stapling
`operation.
`Apair of rectangular apertures 95a and 95b are formed in
`anvil plate 90 adjacent the proximal end thereof for receiv-
`ing a pair of correspondingly positioned flanges 96a and 96b
`which project upwardly away from the tissue contacting
`surface (see FIGS. 2 and 4C). The interaction between
`aperture 95a, 95b and flanges 96a, 96b ensures that the
`cartridge 22 and the anvil plate 90 are properly aligned with
`one another during a stapling procedure. Flanges 96a, 96b
`are spaced proximally of tissue stop portion 61 of retention
`channel 14. Portion 61 and the distal edge 13 of handle
`portion, best seen in FIG. 3, cooperate to prevent tissue from
`extending proximally.
`Referring again to FIG. 2, the anvil half-section of sur-
`gical stapler 10 further includes clamping handle 100 which
`is used to securely clamp tissue between the staple forming
`surface of anvil plate 90 and the tissue contacting surface of
`cartridge 22. Clamping handle 100 is pivotably mounted to
`anvil support beam 80 about a transverse pivot pin which is
`not shown in the drawings. Apair of clamping hooks 102a
`and 102b depend from clamping handle 100 for interacting
`with the U-shaped clamping beam 104 supported within the
`internal cavity defined in handle portion 12.
`When stapler 10 is assembled prior to use, the notched
`area 84 at the proximal end 82 of anvil support beam 80 is
`engaged with the cooperating detents 86 in the inner cavity
`15 of body portion 12. Thereupon, the anvil half-section is
`mated with the cartridge half-section, and clamping handle
`100 is disposed in the upright unclamped position shown in
`FIG. 1A. Subsequently, when body tissue is properly dis-
`posed between the staple forming surface of anvil plate 90
`and the tissue contacting surface of cartridge 22, the anvil
`half section is pivoted toward the cartridge half section,
`about the detents in body portion 12, such that the distal ends
`of clamping hooks 102a and 102b are positioned immedi-
`ately adjacent the proximal end of the base of U-shaped
`clamping beam 104. Concomitantly, flanges 96a and 96b
`engage apertures 95a and 95b in anvil plate 90 to ensure
`proper alignment of the anvil and the cartridge.
`Then, to securely clamp the captured body tissue, clamp-
`ing handle 100 is pivoted from the position illustrated in
`FIG. 1A to that which is shown in FIG. 1B. At such a time,
`clamping hooks 102a and 102b engage the base of clamping
`beam 104,
`locking the stapler in a clamped condition.
`During clamping, the captured body tissue exerts a counter-
`force against the tissue contacting surface of cartridge 22
`and the fastener forming surface of the anvil plate 90, urging
`the two structures apart. To overcome these forces and
`prevent the proximal portion 82 of anvil support beam 80
`from bending, bearing surfaces are defined within the reten-
`tion channel 14 to support the compressive forces generated
`during clamping. In particular, as illustrated in FIG. 4A,
`opposed bearing shelves 110a and 110b are stamp formed in
`the opposed walls 62 and 64 of retention channel 14. The
`bearing shelves are positioned to abut the medial section of
`anvil support beam 80 proximate the clamping handle pivot
`point
`It may also be desirable to provide a locking mechanism
`to prevent reactuation of the apparatus after it has been
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`7
`actuated. For example, a locking member 120 shown in FIG.
`11 can be positioned in the retaining channel 114. The
`locking member 120 is biased to an upward engagement
`position and each end extends through a window 141, 145
`in the channel 114. A T—shaped member 124 is positioned
`between the cam wedges 132, 134 to bias the hook portion
`122 out of engagement with the actuation channel 144. Head
`portion 126 of T—shaped member 124 (FIG. 11A) is initially
`retained in the cartridge by a pair of detents in the cartridge
`which extend into the knife slot. When the stapler is
`actuated, head portion 126 of T—shaped member 124 is
`positioned in the knife slot. A second pair of detents (not
`shown) at
`the distal end of the knife slot engages head
`portion 126 of T—shaped member 124 to hold it at the distal
`end of cartridge 122 when the cam wedges 132, 134 are
`advanced to the distal position. When actuation channel 144
`is retracted from the post-actuated position to the pre-
`actuated position, the T—shaped member 124 remains for-
`ward allowing hook portion 122 to return to the upward
`position and extend through the window 141 in retaining
`channel 114 to engage edge 143 (see FIGS. 12 and 13A) of
`actuation channel 144 to prevent advancement of the actua-
`tion channel. FIGS. 13A, 13B illustrate movement of the
`locking member 120 from an initial non-engaged position
`(FIG. 13A) out of engagement with actuation channel 144 to
`an engaged position (FIG. 13B) in engagement with actua-
`tion channel 144 to prevent distal movement thereof.
`Referring now to FIGS. 14—16, there is illustrated, in
`sequential order, a staple firing operation in which a plurality
`of staples are ejected from cartridge 22 and driven against
`the staple forming surface of anvil plate 90. In operation,
`prior to firing surgical stapler 10, actuation sled 28 is in the
`proximal-most position shown in FIG. 14. At such a time,
`knife blade 36 is enclosed in a protective housing 25 formed
`adjacent the proximal end of disposable loading unit 20. To
`fire the apparatus, firing knob 50 is moved in a distal
`direction. Accordingly, as illustrated in FIG. 15, actuation
`channel 44 drives actuation sled 28 distally into and through
`cartridge 22. During its distal translation, the angled leading
`surfaces of cam wedges 32 and 34 sequentially contact
`ejectors 26, urging them in a direction transverse to the
`direction of movement of actuation sled 28. As a result, the
`ejectors 26 push the staples 24 from their individual slots,
`driving each staple into a respective staple forming cup 91
`in anvil plate 90.
`Sequential firing of the staples continues until actuation
`sled 28 is advanced to the distal end of cartridge 22, at which
`time, all of the staples once housed within the cartridge 22
`win have been ejected (see FIG. 16). Thereafter, the firing
`knob 50 is retracted to its original position, the cartridge and
`anvil sections are separated, and the spent disposable load-
`ing unit 20 is removed from retaining channel 14.
`Subsequently, a new, fully loaded disposable loading unit
`can be positioned in retaining channel 14 such that the slot
`40 of the actuation sled 28 engages the flange 42 of actuation
`channel 44 to enable re-use of the apparatus.
`Although the subject 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 subject apparatus as
`defined by the appended claims.
`What is claimed is:
`
`1. A surgical stapler comprising:
`a) a first body portion supporting an anvil which defines
`a fastener forming surface;
`b) a second body portion configured to releasably mate
`with the first body portion;
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`c) a disposable loading unit removably supported in the
`second body portion and including:
`i) a cartridge defining a plurality of slots and a tissue
`contacting surface;
`ii) a plurality of surgical fasteners disposed in the slots
`of the cartridge;
`iii) a plurality of ejectors positioned adjacent the sur-
`gical fasteners; and
`iv) an actuator configured to translate through the
`cartridge to sequentially interact with the ejectors,
`the actuator having engagement structure; and
`d) an elongated actuation member mounted for longitu-
`dinal movement within the cartridge,
`the elongated
`actuation member having an engagement member
`releasably coupled to the engagement structure to
`enable pushing and pulling of the actuation member to
`effect movement of the actuation member in proximal
`and distal directions, respectively.
`2. A surgical stapler as recited in claim 1, wherein the first
`body portion includes an elongate anvil support member and
`a pivoting lever handle for approximating the first and
`second body portions.
`3. A surgical stapler as recited in claim 2, wherein the
`anvil includes an anvil plate formed separate from the first
`body portion and includes a plurality of staple forming
`pockets defining the anvil forming surface.
`4. A surgical stapler as recited in claim 3, wherein the first
`body portion has an anvil support member and the anvil
`plate includes means for engaging the anvil support member
`during assembly of the surgical stapler to securely