llllllflfilllllllililllllllilllllllilflllllllllillllllllllll
`
`US005800449A
`
`United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,800,449
`
`Wales
`
`[45] Date of Patent:
`
`Sep. 1, 1998
`
`[54] KNIFE SHIELD FOR SURGICAL
`]NsTRU1v[ENTs
`
`-
`.
`Inventor‘ Kenneth S’ wales’ Mason’ Ohm
`[75]
`173] Assignee: Ethicon En-lo-Surgery, Inc.
`Ciflcillflafia 0hi0
`
`[21] Appl. No.: 816,017
`
`5,458,598 10/1995 Fdnberg et al.
`5,462,546 10/1995 Rydell
`5527319
`6/1996 Green etal
`5,573,534 11/1996 Stone
`5,573,535 ll/1996 Viklund
`Primary EJaaminer—Michael Powell Buiz
`Assistant Examiner—Daphna Shai
`Attorney, Agent, or Finn—Bema1‘d Shay
`
`[57]
`
`ABSTRACT
`
`606/52
`.606/51
`606/170
`
`606/51
`
`Mar’ 11’ 1997
`
`A6111 17/32
`606/172; 606/170; 606/205;
`605/205; 506/207; 505/45; 606/43
`606/170, 172,
`f Se
`63312105 206 207 37 41 45 46 43 49
`’
`’
`'
`'
`’50 ’51 ’52 ’16—,’
`’
`’
`'
`
`[22] Filed:
`[51]
`Int. (31.5
`[52] U.S. C1.
`
`Fiel
`
`d 0
`
`58
`I
`]
`
`[55]
`
`A surgical instrument according to the present invention
`inclujies a handle, an elongated clrgsure tube, an end eifector,
`8 Parr of wlreform clemcnts which may be, for example,
`wireform conductors, extending thmugt the elongated tube
`f'°"1 '3“ “"515 ‘° “*6 end °‘7°°"‘°‘ 3"“ 3 k“if° 5134“ "1 3"’
`end effector and :1 tissue stop adapted to shield the knife
`blade when the lmife blade is in its proximal most position.
`In a surgical instrument according to the present invention,
`the wireform elements are positioned within wireform guide
`channels formed in the tissue stop. In a surgical inslmment
`U-S- PATENT S according to the present invention, the closure tube includes
`1/1937 Wappler et al.
`123/309.15
`“_“5‘°"‘E 5"°P m°1“‘*§“8 *' ‘W31 ‘M and *1 P‘°"“"{“ °“"- Tm’
`2,068,721
`4/1937 Iischer
`.. 12s/303.1
`"SW5 SEOP Wm“ Includes {1 b°dY« 3 Wk if knife h°“S1D8
`4,655,216
`5,174,300 1911992 Bales at :11.
`12s/751
`and knife channel. 1116
`lmlfe Channcl bcmg adapted to
`5,253,006 11/1993 Rydefl at 31,
`, 505/205
`support the shank of the knife as it moves within the knife
`5,342,359
`8/1994 Rydell
`606/51
`channel.
`5,403,342
`4/1995 Tovey et al.
`Rydell :1 al.
`
`References Cimd
`
`.........................
`
`606/51
`
`9 Claims, 7 Drawing Sheets
`
`ETHICON ENDO-SURGERY, INC.
`
`EX. 1008
`
`1
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`

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`U.S. Patent
`
`19n.eS
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`8991
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`Sheet 1 of 7
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`2
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`

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`Sep. 1, 1993
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`Sheet 2 of 7
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`5,800,449
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`3
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`

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`U.S. Patent
`
`19m.eS
`
`89911
`
`Sheet 3 of 7
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`4
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`

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`U.S. Patent
`
`,4S
`
`la
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`%91
`
`Sheet 4 of 7
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`5
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`

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`U.S. Patent
`
`Sep. 1, 1993
`
`Sheet 5 of 7
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`5,800,449
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`6
`
`

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`U.S. Patent
`
`,
`
`Sep. 1, 1998
`
`Sheet 6 of 7
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`5,800,449
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`7
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`

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`U.S. Patent
`
`Sep. 1, 1993
`
`Sheet 7 of 7
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`5,800,449
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`8
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`

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`5 , 800,449
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`1
`KNIFE SHIELD FOR SURGICAL
`INSTRUMENTS
`
`This application is related to the following patent appli-
`cations: application Ser. No. 08/537,065; application Ser.
`No. 08/536,726; application Ser. No. 08f75 1,898; applica-
`tion Ser. No. 08/555,741; application Ser. No. 08/761,411;
`application Ser. No. 08/762,218; and application, Ser. No.
`08/816,020.
`
`FIELD OF THE INVENTION
`
`The present invention relates, in general, to a tissue stop
`for use with a surgical instrument and, more particularly, to
`an improved tissue stop including a knife shield for use with
`an electrosurgical instrument.
`
`BACKGROUND OF THE INVENTION
`
`Electrosurgical instruments are used by surgeons to apply
`electrosurgical energy to tissue. Electrosurgical devices are
`used for eifecting improved hemostasis by heating tissue and
`blood vessels to cause coagulation or cauterization.
`Monopolar electrosurgical devices utilize one active elec-
`trode associated with the cutting or cauterizing instrument
`and a remote return or ground electrode which is usually
`attached externally to the patient. Thus, in surgery utilizing
`monopolar instruments, electrical current passes from the
`active electrode, through the patient to the return electrode.
`In bipolar electrosurgical instruments, both electrodes are
`included on the instrument and, generally, both electrodes
`are active. Thus a typical bipolar instrument includes two or
`more electrodes which are charged to ditferent electrical
`potentials. In bipolar eleclrosurgical instruments, the tissue
`is treated by passing electrical current through tissue posi-
`tioned between the electrodes.
`
`Electrical energy is used in medical instruments for a
`number of purposes including hemostasis, i.e. to stop or
`slow bleeding in tissue. Application of electrical cmrent in
`conjunction with pressure applied by the end eifeaor of a
`surgical instrument results in a significant reduction in
`bleeding. Thus, electrical current may be used to cauterize
`tissue prior to cutting the tissue, reducing or eliminating
`bleeding around the cut. The electrical cmrent which passes
`through the tissue acts to heat the tissue. As the tissue is
`heated, it changes in color and texture. The experienced
`surgeon may, by looking for changes in the color or texture
`of the tissue around the end eifector, determine when to turn
`olf the cunent to the end effector. Once the tissue has been
`treated and the cun'ent turned of, the tissue grasped by the
`end etfecttr may be cut by, for example, advancing a knife
`blade through the tissue in the end eifectcr.
`Bipolar forceps, being one type of bipolar electrosurgical
`instrument, have been used in various procedures for coagu-
`lating tissue. Generally bipolar forceps include two oppos-
`ing jaws each conneaed to an output electrode of an
`electrical generator such that, when the generator is turned
`on, the opposing jaws are charged to diiferent electrical
`potentials. Organic tissue being electrically conductive, the
`charged electrodes apply electrical current
`through the
`grasped tissue Once the tissue has been treated to limit
`blood flow, a knife or other cutting instrument may be used
`to cut the tissue. In most such devices, the knife is positioned
`to travel through a knife channel in the instrument wherein
`the knife channel positions and supports the knife as it
`moves. In such devices, tissue stops act to prevent tissue
`from being positioned past the proximal end of the end
`effector’.
`
`2
`In other electrosurgical instruments such as certain types
`of bipolar forceps, the end effector includes a knife channel
`capable of supporting the knife as it moves through the jaws
`of the end elfector. In such devices it would be desirable to
`protect tissue engaged by the jaws of the forceps until the
`surgeon desires to art the engaged tissue. It would also be
`desirable to limit the travel of the knife to the length of the
`end effector in order limit the amount of motion the surgeon
`has to apply to cut engaged tissue.
`In bipolar forceps
`wherein the jaws of the end elfector are supported by
`wireform conductors it may be difficult to align the jaws of
`the end effector as the end efiector is closed since the jaws
`may have a tendency to shift as the closure tube passes over
`the wireform conductors. It would, therefore, be advanta-
`geous to design a tissue stop including a knife shield such
`that when the knife is in its proximal most position, the knife
`blade is positioned in the knife shield within the tissue stop
`and the distal end of the tissue stop is between the jaws. It
`would also be advantageous to design a tissue stop which
`includes a support channel adapted to provide support to the
`knife as it uavels through the end effector. Finally, it would
`be advantageous to design a tissue stop as set forth above
`wherein the tissue stop included guide channels for the
`wireform conductors, the guide channels being adapted to
`guide and support the wireform conductors as the closure
`tube moves in a proximal to distal direction.
`SUMMARY OF THE INVENTION
`
`A surgical instrument according to the present invention
`includes a handle, an elongated closure tube, an end efieaor,
`a pair of wireform elements which may be, for example,
`wireform conductors, extending through the elongated tube
`from the handle to the end effector and a knife blade at the
`end etfector and a tissue stop adapted to shield the knife
`blade when the knife blade is in its proximal most position.
`The wireform conductors are connected to and support the
`jaws of the end efiector. The knife blade is connected to the
`handle through a push bar which passes through the elon-
`gated tube. In a surgical inst:rument according to the present
`invention, the push bar is positioned between the wireform
`elements and is axially moveable with respect to the wire-
`form elements. In addition, in a surgical instrument accord-
`ing to the ixesent invention, the wireform elements are
`positioned within wireform guide channels formed in the
`tissue step.
`instrument according to the present
`In a surgical
`invention, the closure tribe includes a tissue stop including
`a distal end and a proximal end The distal end of the tissue
`stop includes a lmife blade slot. The tissue stop further
`includes a knife channel connecting the distal end to the
`proximal end, the knife channel being adapted to support the
`shank of the knife as it moves within the knife channel. In
`addition, first and second wireform guide channels are
`formed on the exterior surface of the tissue stop. In a furtha
`embodiment of the present invention, the wireform guide
`channels include rib elements which are adapted to mate
`with slots in said wireform demerits to position the wire-
`form elements and hold the tissue stop in place as the closure
`tube is moved from its proximal to its distal position.
`In a further embodiment of the present invention, the
`tissue stop includes a body at its proximal end, a knife
`housing at its distal end and a neck portion connecting said
`body and said knife housing. In this embodiment of the
`present invention, the knife housing is positioned between
`the jaws of the end etfector and includes an elongated slot
`adapted to receive a knife blade. The neck portion of the
`tissue stop is positioned at the intersection of the end effector
`
`9
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`

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`5,800,449
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`3
`jaws and the wireforms while the body is positioned proxi-
`mal of the jaws of the end etfector. In a further embodiment
`of the present invention, one of the jaws is aflixed to the
`tissue stop.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The novel features of the invention are set forth with
`particularity in the appended claims. The invention itself,
`however, both as to organization and methods of operation,
`together with further objects and advantages thereof, may
`best be understood by reference to the following description,
`taken in conjunction with the accompanying drawings in
`which:
`
`FIG. 1 is a perspective View of an electrosurgical insn'u-
`meat.
`
`FIG. 2 is a side elevational View of an electrosurgical
`instrument shown with the jaws of the end effector in a first,
`unclamped position.
`FIG. 3 is a side elevational View of an electrosurgical
`instrument shown with the jaws of the end effector in a
`second, clamped position.
`FIG. 4 is a perspective view of an electrosurgical instru-
`ment of the present invention with the left side of the handle
`removed.
`
`FIG. 5 is an exploded view of a portion of the internal
`mechanism of the handle illustrated in FIG. 4.
`
`FIG. 6is an exploded perspective view ofaportion ofthe
`intunal mechanism at the distal end of one embodiment of
`an electrosurgical instrmnent including a tissue stop accord-
`ing to the present invention.
`FIG. 7 is a perspective view of an end doctor according
`to one embodiment of the present invention.
`FIG. 8 is a side view of the end effector according to one
`embodiment of the present invention.
`FIG. 9isasideview ofanendetfectoracctrdingtoone
`embodiment of the present invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`FIG. I is a perspective view of a surgical instnnnent
`according to the present invention. The surgical instrument
`of FIG. 1 may be referred to herein as a bipolar forceps. In
`bipolar forceps 10, illustrated in FIG. 1, jaws 214 and 216
`of end effedor 12 are supported by upper wirdorm 14 and
`lower wireform 16. Wire forms 14 and 16 may also act as
`electrical conductors, supplying bipolar electrical entrgy to
`end effector 12. Tissue stop 18 is positioned within tube 20.
`Tube 20 may be, for tire present example, an elongated
`hollow closure tube extending from handle 26 toward end
`efiector 12. Rotation knob 22 is attached to closure tube 20
`tocaI1serotationofc|osIrret11be20andendcfi‘ector12with
`respect to handle 26. Handle 26 includes knife button 24,
`grip28andtrigger30.Elect:ricalcord34isconnect.edto
`ha.ndle26throughstrainrclief32.'I‘riggerlat.d:t36is
`positioned on trigger 30. Handle latch shield 38 is positioned
`on grip 28.
`As illustratedin FIG. 2, end effector 12 of bipolar forceps
`10 has a firs! open position when trigger 30 is open. As
`illustrated in FIG. 3, end effector 12 of bipolar forceps 10
`has a second closed position when trigga 30 is in the closed
`position. Movement of trigger 30 in direction Al moves
`closuretube20i.n directionA2toforce wireforms 14 and 16
`together, forcing the jaws of end effector 12 in direction A3.
`In the closed position, as illustrated in FIG. 3, end effector
`
`4
`12 is adapted to grasp tissue 40. Tissue 44) is positioned
`within jaws 214 and 216 at the proximal end of end eifector
`12. The distal end of tissue stop 18 prevents tissue 40 from
`moving past the grasping portion of jaws 214 and 216. In
`addition. the distal end of tissue stop 18 positions tissue 40
`adjacent to knife blade 94 to facilitate cutting. Movement of
`knife button 24 in direction B1 moves knife 42 out of tissue
`stop 18 in direction B2. Movement of knife 42 in direction
`B2 cuts tissue positioned in end etfector 12.
`FIG. 4 is a perspective View of bipolar forceps 10 with the
`left side of grip 28 removed. In FIG. 4, handle latch 44 is
`illustrated. Wire form anchor 46, which is adapted to receive
`the proximal end of upper wireform 14 and lower wireforrn
`16,isattachedtointeriorstrainrelief48whicl1inturnisa
`part of strain relief 32. Trigger yoke 56 on trigger 30 may
`include trigga yoke cam face 52.
`FIG. 5 is an exploded view of a pcrtion of the internal
`mechanism of the handle illustrated in FIG. 4. In FIG. 5, the
`proximal end of push bar 54 is adapted to fit with connector
`100 in hub 98. In the embodiment of the invention illustrated
`in FIG. 5, connector 100 and hub 98 cooperate to form
`coupler 99. Ribs 60 on knife button 24 are adapted to slide
`within the handle and guide knife button 24 as it moves
`axially along the handle 26. Yoke 62 of knife button 24
`includes hub slot 64 which is adapted to receive knife hub
`98.Rib68ofwi1'eformanchor46isadaptedtofitwit:hin
`slots 110 and 112 of upper wireform 14 and lower wireform
`16, respectively. Wireforms 14 and 16 each include insula-
`tion lays 15 and an electrical conductor 17. Knife return
`spring 70 wcrks against lmife spring retainer 72 to provide
`a counter force which counters the movement of button 24
`in direction B1. Clostne tnbe collar 14 is adapted to fit ova‘
`the maximal end of closure tube 20 and includes chive rib 76
`and retract rib 78, which intuaa with trigga yoke 50 as
`illustrated in FIG. 4. Closure tube washer 80 is adapted to fit
`within slots in closure tube 23 to hold closure tnbe collar 74
`inplaceclosuretubewashersoalso acsstoretaintrigger
`rettun spring 82. Closure tube washer80 is guided axially by
`washer ribs 84 and rotation knob 22. Electrical connectors
`102 and 104 are positioned within interior strain relief 48
`and connected to upper wirefrrm proximal connector 106
`and lower wireform proximal connector 108 respectively to
`form an electrical comedian between wireforms 14 and 16
`and chord 34. Slot 110 in upper wireform 14 and slot 112 in
`lower wireform 16 are adapted to mate with ribs 68 and 69,
`respectively, in wireform anchor 46.
`In FIG. 5, coupler 99 comprises hub 98 and a connector
`100 disposed within hub 98. Connector 100 includes a pair
`of connector legs 200 and a bridge 202 connecting con-
`nected legs 200. Connector legs 200 include books 204
`whicharedesignedtograspthepushbar54 such thataxial
`movement of coupler 99 moves push bar 54 along the axis
`of elongated tube 20. In addition, rotational movement of
`couple 99 results in rotational movement of push bar 54.
`Wireforms 14 and 16 pass through hub 98 of coupler 99 on
`either side of connector 100, thus allowing coupler 99 and
`push bar 54 to move axially without moving wireforms 14
`and 16 axially. Rotational movement of coupler 99, on the
`other hand, results in rotational movement of wireforms 14
`and 16 in conjunction with push bar 54. Thus, where
`Wireforms 14 and 16 are connected to jaws 214 and 216 of
`end effector 12 andpush bar54 is connected to a working
`tool such as knife 42. the working tool may be moved axially
`independent of wireforms 14 and 16 of end effector 12 while
`the working tool moves rotationally in conjunction with
`wireforms 14 and 16 and with end effector 12.
`FIG. 6 is an exploded perspective view of the intunal
`mechanisms of bipolar forceps 10 atthe distal end of closure
`
`10
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`5,800,449
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`5
`tube 20. In FIG. 6, upper Wireform distal connector 114 may
`be soldered or welded to upper end eflector jaw 214 to form
`a mechanical and electrical connection between jaw 12 and
`wireform 14. Similarly, lower Wireform distal connector 116
`may be soldered or welded to lower end effector jaw 216.
`Upper Wireform 14 and lower wireform 16 are biased away
`from tissue stop 18 at their distal end. Therefore, jaws 214
`and 216 of end effector 12 are biased in the open position
`when closure tube 29 is retracted. Wireforms 14 and 16 may
`be biased away from tissue stop 18 by, for example, spring
`action resulting from forming wireforms 14 and 16 with an
`outward bend near their distal end, as illustrated in FIG. 6.
`End eifector 12 may be closed by forcing wireforrns 14 and
`16 together, thus forcing jaws 214 and 216 together. As
`illustrated in FIG. 4, knife 42, which is connected to knife
`button 24 by push bar 54 and coupler 99, includes knife
`blade 94 and knife edge 96. Upper Wireform 14, and lower
`Wireform 16 pass through gas seal 118 which is positioned
`in the distal end of closure tube 20. Tissue stop 18 is
`positioned distal to gas seal 118. Closure tube 20 may be
`surrounded by an electrical insulator 120 such as shrink
`wrap tubing. Slot 86 in llppfl Wireform 14 is adapted to mate
`with rib 88 in tissue stop 18. Similarly, slot 92 in lower
`wireform 16 is adapted to mate with rib 93 in tissue stop 18.
`Slot 90 in tissue stop 18 is adapted to receive knife blade 94
`when knife button 24 is in its proximal position (ie. when
`it is retracted). Knife slot 90 also acts to protect knife edge
`96 of lmife blade 94. Thus, tissue stop 18 may altunately be
`referred to as a knife guard.
`In the embodiment of the invention illustrated in FIG. 6,
`tissue stop 18 is positioned within closure tube 20 and held
`in place by closure tube 20 andribs 88 and 93 which fit into
`slots 86 and 92 of upper Wireform 14 and lower wirefrrm 16
`respectively. Ribs 88 and 93 are located within wireform
`guide channels 85 and 87, respectively. Knife shank 95 and
`push bar 54 pass through tissue stop knife channel 91 which
`extends from the proximal end of tissue stop 18 to slot 90 in
`end surface 89 at the distal end of tissue stop 18. Knife
`channel 91 is adaptedto support knife shank95 andpush bar
`54, thus providing support to knife blade 94 as it moves from
`its proximal position to its distal most position At least a
`portion of knife channel 91 conforms to the shape ofknife
`shank:95toprovide supporttoknife shank95.K.nifeblade
`slot 90 is adapted to receive knife blade 94, shielding knife
`edge 96 from tissue positioned in end effector 12 when knife
`42 is in its proximal most postion. Distal end surface 89 of
`tissue stop 18 prevents tissue grasped by end effector 12
`from contacting knife edge 96 and, in addition, positions the
`tissue within jaws 214 and 216 by preventing the tissue from
`moving past the proximal d of end effector 12.
`As illustrated in FIGS. 7-9, in an alternate embodiment of
`the present invention, one of jaw 214 or jaw 216 may be
`fixed in place by, for example, fixing one of upper Wireform
`14 or lower wireform 16 to tissue stop 18. Alternatively, one
`ofjaw 214 orjaw 216 may be fixed in place by, for example,
`biasing one of upper wireform 14 cr lower wireforrn 16
`against tissue stop 18. Wireforms 14 or 16 may be biased
`toward tissue stop 18 by, for example, spring action resulting
`fi'om forming wireforms 14 or 16 with an inward bend near
`their distal end.
`
`Referring now to FIGS. 7-9, tissue stop 18 includes a
`body 320, a neck 322 and a blade housing 324 Body 320
`includes knife channel 91 and upper slot 86 and lower slot
`92 which are adapted to receive, hold and guide wireforms
`14 and 16. Neck 322 of tissue stop 18 is adapted to conned
`blade housing 324 to body 320. Neck 322 is positioned at the
`intersection of wireforms 14 and 16 with jaws 214 and 216.
`
`6
`Because neck 322 is positioned at the intersection of jaws
`214 and 216 with wire forms 14 and 16 it is smaller than
`either body 320 or blade housing 324. Blade housing 324 is
`positioned within jaws 214 and 216 and distal to the distal
`ends of wireforrns 14 and 16. Blade housing 324, being
`adapted to hold blade 94 and to include end surface 89 is
`larger than neck 322 and is elongated in shape. Blade
`housing 324 has an elongated shape to guide jaw 214 to mate
`with jaw 216 as end etfector 52 is closed. The shape of tissue
`stop 18 is particularly advantageous in small electrosurgical
`instruments which are adapted to fit through trocars having
`a diameter of five millimeters or less. In such instruments, it
`is important to have an actuatable blade which is large
`enough to cut all of the tissue engaged by the jaws of the end
`effector. In addition, it is important to include a housing
`which protects the tissue from blade edge 96 when the knife
`is retracted. It is further necessary to provide sufficient
`support and stifiness to the Wireform-jaw interconnection to
`ensure that the jaw can firmly grasp and manipulate tissue.
`The design of tissue stop 18 is particularly adapted to meet
`those objectives. The elongated shape of blade housing 324
`is advantageous because it facilitates the proper positioning
`ofjaws 214 and 216 as end etfector 12 is closed, preventing
`jaws 214 and 216 from being ofiset as end eifector 12 is
`,5 closed.
`Referring now to FIGS. 2 and 3, the operation of a
`surgical instrument according to the present invention may
`be described. In FIG. 2, end eflector 12 is open, l-mife button
`24 is in its proximal position and trigger 30 is open. When
`trigger 30 is closed, closure tube 21) slides forward over
`upper and lower wireforms 14 and 16, closing end etfector
`12. Alternatively, as illustrated in FIGS. 7-9 in an embodi-
`ment of the present invention wherein, for example, jaw 216
`is fixed, when trigger 30 is closed, closure tube 20 slides
`forward over wireform 14, forcing movable jaw 214 against
`fixed jaw 216 and closing end eflector 12. Knife 42 is
`deployed by moving lmife button 24 from its proximal to its
`distal position in direction B1, thus cutting tissue positioned
`within end effector 12 Handle latch 44 is adapted to hold
`trigger 30 in position until released, by, for example, squeez-
`ing trigger 30 a second time.
`When trigger 30 is moved to its closed position, dosure
`tube 20 is forced to its most distal position. Referring now
`to FIG. 4 and FIG. 5. as trigger 30 is closed, drive rib 76
`moves along cam face 52. Drive rib 76 is forced against cam
`face 52 by the action oftrigger return spring 82 whidr acts
`against closure tube washer 80 whid: engages closure tube
`20 and closure tube collar 74. Tissue stop 18, being engaged
`by the interaction of ribs 88 and 93 with slots 86 and 92 in
`wirefornm 14 and 16 does not move when closure tube 20
`moves from its proximal to its distal position. Thus, closure
`tube 20 slides over tissue stop 18 and w-ireforms 14 and 16,
`forcing wireforms 14 and 16 into wireform guide channels
`85 a.nd8‘7.Aswireforms 14 and16 areforcedintowireform
`guide channels 85 and 87, jaws 214 and 216 of end etfector
`12 are forced together, closing end eifector 12. Wireform
`guide channels 85 and 87 position and align wireforms 14
`and 16, thus positioning and aligning jaws 214 and 216 and
`ensuring that jaw 214 is accurately aligned with jaw 216 as
`the jaws are closed by the proximal to distal movement of
`closure tube 20. As trigger 30 is released, trigger return
`spring 82 forces closure tube collar '74 back by acting on
`closure tube washer 80. As closure tube 20 moves in a distal
`to proximal direction, wireforms 14 and 16 move apart,
`separating wireform jaws 214 and 216 and opening end
`etfector 12. If for some reason closure tube 20 or end effector
`12 becomes stuck, the interior face of trigger yoke 50 may
`
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`5 ,800,449
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`be used to force closure tube collar 74 towards the proximal
`end of the instrument, thus opening the end efiector. Handle
`latch 44 releasably engages trigger latch 36 such that by
`further pressure on trigger 30, latch 36 is released.
`Referring now to FIGS. 4 and 5, knife button 24 is used
`to move knife b% 94. As knife button 24 is moved in a
`proximal to distal direction, yoke 62 moves in a proximal to
`distal direction. Coupler 99 being positioned in hub slot 64,
`the movement of yoke 62 in a proximal to distal direction
`moves coupler 99 in a proximal to distal direction. Coupler
`99 being attached to push bar 54, movement of coupler 99
`in a proximal to distal direction moves push bar 54 axially
`through closure tube 29 in a proximal to distal direction.
`Push bar 54 being connected to knife 42, movement of push
`bar 54 in a proximal to distal direction results in movement
`of knife 42 in a proximal to distal diredion. Thus, movement
`of knife button 24 in a proximal to distal direction results in
`movement of knife 42 in a proximal to distal direction.
`likewise, movement of knife button 24 in a distal
`to
`proximal direction results in movement of coupler 99, push
`bar54 andknife42in a distaltoproximaldirection. Pushbar
`54 moves through closure tube 20 on a line which is
`substantially parallel to the central axis of closure tube 20.
`Wireform conductors 14 and 16, which are positioned on
`either side of push bar 54, pass throng: coupler 99 such that
`jroximal to distal or distal to proximal movement of coupla
`99 does not result
`in movement of either of wireform
`conductors 14 or 16.
`
`Referring now to FIGS. 4, 5 and 6, rotation of rotation
`knob 22 results in rotation of end eifector 12, including
`wireform conductors 14 and 16 and knife 42. When rotation
`knob 22 is turned or rotated, that rotational motion is
`transmitted to closure tube washer 80 which rotates dosure
`tube 20. Closure tube 20 being connected to wireform
`conductors 14 and 16 through closure tube washer 80,
`rotational movement of closure tube 20 results in rotational
`movement of wireform conductors 14 and 16. Push bar 54,
`being positioned between wirefcrm conductors 14 and 16
`and attached to knife 42, rotational movement of wireform
`conductors 14 and 16 results in rotational movement of push
`barS4which,intJn'n,rotates coupler99. Coupler99rotates
`freelywithinhub slot64ofyoke 62allowingpushbar54
`rotate with wireform conductors 14 and 16.
`Itwillbeapparenttothoseofskillintheartthatan
`instrument including a tissue stop according to the present
`invention will have a number of advantages. In particular,
`such a tissue stop will provide a protective cover for the
`knife blade, preventing it from nicking tissue and reducing
`the potential for unintentional electrical arcing between the
`jaws and the blade in an eledro-surgical instrument. In
`addition, as previously stated, the distal face of the tissue
`stop prevents tissue from getting lodged behind the back of
`the jaws, facilitating proper cauterization of the tissue.
`Further, the wireform guide channels in the tissue stop assist
`in accurately aligning the wireforms and the jaws axially
`whiletheribsinthewireformguidechannelsassistin
`accurately aligning the distal end of the jaws. Finally, the
`tissue stop prevents the retracted knife blade from being
`pinched by the wirefoerms when the jaws are closed.
`While preferred embodiments of the present invention
`have been shown and described herein, it will be obvious to
`those skilled in the art that such embodiments are provided
`by way of example only. Numerous variations, changes, and
`substitutions will now occur to those skilled in the art
`without departing from the invention. Accordingly, it is
`intended that the invention be limited only by the spirit and
`scope of the appended claims.
`
`8
`
`What is claimed is:
`1. A surgical instrument including a handle, an end
`effector and an elongated closure tube connected to said
`handle and adapted to actuate said end etfector comprising:
`a tissue stop for use in a surgical instrument, wherein said
`tissue stop comprises:
`a distal end and a proximal end;
`a body at said proximal end;
`a knife housing at said distal end;
`a neck interconnecting said body and said knife hous-
`mg;
`a knife blade slot in said lmife housing at said distal
`end;
`a knife channel connecting said distal end to said
`proximal end through said body, said neck and said
`housing;
`a first wireform guide channel on a first side of said
`body; and
`a second wirefonn guide channel on a second side of
`said body;
`a first wireform element passing through said elongated
`tube on a first side of said tissue stop;
`a second wirefonn element passing through said elon-
`gated tube on a second side of said tissue stop;
`a knife positioned within said tissue stop whuein said
`knife includes a black: positioned in said knife blade
`slot;
`aknifeedge ata distal endofsaidknife blade suchthat
`the entirety of said knife edge is contained within said
`slot when said knife is in a proximal position.
`2. A surgical instrument according to claim 1 wherein said
`first wireform guide channel includes a rib element adapted
`to engage a slot in said first wireftrm element and said
`second wireform guide channel includes a rib element
`adapted to engage a slot in said second wireform guide
`channel.
`3. A surgical instrument according to claim 2 wherein said
`knifeincludes aknife shankwhich is moveablewithin said
`knife channel, said knife channel providing support for said
`knife shank.
`4.Asurgical instrumentaccordingtoclaiml whereinsaid
`first wireform element is connected to a first jaw of said
`surgical instrument and said second wireform element is
`connected to a second jaw of said surgical instrument.
`5. An electrosurgical instrument comprising:
`a handle;
`an end effector operatively connected to said handle
`through an elongated tube;
`first wireformmeans for supporting a first jaw of said end
`eifector wherein said first wireform means extends
`from said handle to said first jaw through said elon-
`gated tube;
`second wirefrrm means for supporting a second jaw of
`said end effector wherein said second wireform means
`extends from said handle to said second jaw through
`said elongated tube;
`a knife means for culling tissue, said knife means being
`moveable within said end efiector and including a knife
`edge at a distal end thereof;
`button means for moving said knife means, said button
`means being positioned on said handle;
`tissue stop means for positioning tissue engaged by said
`end effector, wherein said tissue stop means comprises:
`a distal end and a proximal end;
`a body at said proximal end;
`
`12
`
`

`
`5,800,449
`
`9
`a knife housing at said distal end;
`a neck interconnecting said body and said knife hous-
`1113:
`a knife blade slot in said knife housing at said distal
`end; wherein said knife edge is positioned such that
`the entirety of said knife edge is contained within
`said knife blade slot when said knife means is in a
`proximal position;
`a knife channel connecting said distal end to said
`proximal end through said body, said neck and said
`housing;
`a first wireform guide channel on a first side of said
`body; and
`a second wireform guide channel on a second side of
`said body.
`6. A surgical instrument according to claims wherein said
`first wireform guide channel includes a rib element adapted
`
`10
`to engage a slot in said first wireform means and said second
`wireform guide channel includes a rib element adapted to
`engage a slot in said second wireforrn means.
`7. A surgical instrument according to claim 6 wherein said
`knife includes a knife shank means adapted to support a
`knife blade wherein said knife shank is moveable within said
`knife channel, said knife channel providing support for said
`knife shank means.
`8. A surgical instrument according to c1ai1n5 wherein said
`first wireform means is connected to a first jaw of said
`surgical instrument and said second wireform means is
`connected to a second jaw of said surgical instrument.
`9. A surgical instalment according to claim 8 wherein said
`knife housing is positioned between said jaws and is elon-
`15 gated in a direction parallel to the movement of said jaws.
`it
`*
`4'
`IF
`*
`
`13