00O00l904H
`United States Statutory Invention Registration [191
`[ll] Reg. Number:
`[45] Published:
`
`Yates et al.
`
`H1,904
`Oct. 3, 2000
`
`[75]
`
`[54] El.E(.'l‘RDSURGlCAL HEMOS'l‘A'l‘IC
`METHO” AND DEVICE
`Inventors: David C. Yates. West Chester. James
`W. Voegele; Jesse Kulms. both of
`Cincinnati; Anil Nalagalla. West
`Eoa::fl?i':a;v:?3fu,:' wmjmnsan’ Iv’
`
`Anaignee: Ethicon Endo-Surgery, Ine..
`Cincinnati. Ohio
`
`‘
`APPL No" 08356520
`Filed:
`May 14, 1997
`A613 l8ll8
`till. CI.’
`“"50? 505M“? 5051413
`U-S- (1
`509453 W949: 505"”? M91433 5053305
`Field of Searth
`606/41. 45-52.
`505/l41’~143. 205-209
`“dare” Cited
`U.S. PATENT DOCUMENTS
`
`128034
`
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`3.398.993
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`5.383.880
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`5.403.3I2
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`s.735.s4s M993 Yates et at
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`5.8l0.3H
`FOREIGN PATENT DOCUMENTS
`0 no 315 Al
`‘M993 European Pat. OE.
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`0 m 950 A2 H1996 European Pas. otr. _
`0 737 446 Al
`1on99o
`European Fat. or. .
`Primary I-Ztamim-r-—Howard J. Tudor
`[57]
`ABSTRACT
`
`An electrostu-gical instrument is provided for cauterization
`andfor welding of tissue of varying impedance. thickness
`and vascular-ity es
`cially in the
`ormanoe of endoscopic
`procedures. The ifitrutnent comgbfsses the tissue between
`one pole of a bipolar energy source located on one inter-
`facin surface. and a second interfacin surface at:
`1
`‘:13
`prcsmglm in 3 pmdetemfined range. A secfind Pole is l§c):‘ed
`one of the two interfacing surfaces.
`In a preferred
`embodiment. the second pole is located on the same inter~
`facing surface as the first pole and an insulator elect:-icaily
`isolates the two poles. A preferred application of the inven-
`tion is in a cutting instrument wherein a hemostatic line is
`formed along a cut line using RF energy.
`
`1 Claim. 12 Drawing Sheets
`
`A statutory invention registration is not a patent. It has
`the defensive attributes of in patent but does not have the
`enforceable attributes of a patent. No article or adven-
`.
`tlsemu-it or the like may use the term patent, on-any term
`s“83°“i"° 0‘ 3 Pmfllv ‘"1"’ ”5°''l''1'8 “' 3 5‘3“"°"!’
`invention registration. For more specific information on
`the rights associated with a statutory invention registra-
`tion see 35 U.S.C. 157.
`
`.
`
`ETHICON ENDO-SURGERY, INC.
`
`EX. 1012
`
`1
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`

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`Sheet 1 of 12
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`2
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`

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`US. Patent
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`Oct. 3, 2000
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`Sheet 2 of 12
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`U.S. Patent
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`Oct. 3,2000
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`Sheet 3 of 12
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`FIG. 3
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`42
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`

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`U.S. Patent
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`Oct. 3, 2000
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`Sheet 4 of 12
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`5
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`

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`U.S. Patent
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`Oct. 3, 2000
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`U.S. Patent
`
`Oct. 3, 2000
`
`Sheet 6 of 12
`
`FIG. 10
`
`APPLY
`
`ELECTRICAL
`ENEHG Y
`
`DETEHMINE
`SYSTEM CURRENT
`AND VOLTAGE
`
`CALCULATE
`IMPEDANCE
`VALUE AND
`STORE
`
`DETERMINE
`F (2)
`
`IS
`IMPEDANCE
`VALUE WITHIN
`NORMAL
`RANGE ?
`
`F (2')
`INDICATE THAT
`COAGULATE LEVEL
`HEACHED
`9
`
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`AND
`mD:cA1'E
`E3303
`
`INDICATE
`GOAGULA TION
`COMPLETED
`
`7
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`U.S. Patent
`
`Sheet 7 of 12
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`8
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`Oct. 3, 2000
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`Sheet 8 of 12
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`9
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`U.S. Patent
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`Oct. 3, 2000
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`Sheet 9 of 12
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`10
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`11
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`U.S. Patent
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`12
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`

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`

`
`Hl,904
`
`I
`ELECTROSURGICAL HEMOSTATIC
`MF.'I'HOD AND DEVICE
`
`FIELD OF THE INVENTION
`
`This invention relates to an improved electrosurgicttl
`instrument and met.l1od for cauterization. coagulation andlor
`tissue welding in the performance of surgical procedures.
`especially endoscopic procedures.
`
`'
`
`BACKGROUND OF THE INVENTION
`
`Surgical procedures requiring cutting of tissue can cause
`bleeding at the site of the cutting. Before surgeons had the
`means to control bleeding many surgical procedures were
`quite difficult to perform because of excessive blood loss.
`l-Iernostasis is even more crucial in endoscopic or laparo-
`scopic surgery where if the bleeding is not kept under
`control.
`the laparoscopy must be abandoned and the
`patient's body cut to perfonn open surgery so that inacces-
`sible bleeding may be controlled.
`Tlius. various techniques have been adapted to control
`bleeding with varying degrees of success such as. for
`example. suturing. applying clips to blood vessels. and
`stapling. as well as electrocautery and other thermogenic
`techniques. Advances in tissue joining. tissue repair and
`wotutd closure also have permitted surgical procedures
`previously not possible or too risky.
`Initially. suturing was one of the primary means for
`providing hemostasis and joining tissue. Before other l'lcI'no~
`static and tissue repair means were introduced. surgeons had ‘
`to spend a great deal of tithe sewing the tissue of patients
`back together.
`Stu-gi-ca] clips were introduced as a means to close olf
`blood vessels. particularly when cutting highly voscularized _
`tissue. Application of surgical clips. however. can be cum-
`bersome in certain procedures. The vessels must be identi-
`fied. Then a clip must be individually applied on both sides
`of the intended cut of each identified vessel. Also. it may be
`difficult to find some vessels. particularly where the vessel is
`surrounded by fatty tissue.
`Surgical staplers have been eficctlve in decreasing the
`amount of time it takes to fasten tissue together. There are
`various types of surgical staplers. Staplers have been used
`for tissue joining. and to provide hemostasis in conjunction
`with tissue cutting. Such devices include. for example. linear
`and circular cutting and stapling instruments. Typically. a
`linear cutter has parallel rows of staples with a slot for a
`cutting means to travel between the rows of staples. This
`type of surgical stapler secures tissue for improved cutting.
`joins layers of tissue. and provides hemostasis by applying
`parallel rows of staples to layers of surrounding tissue as the
`cutting means cuts between the parallel rows. These types of
`cutting and stapling devices have been used successfully in
`pi-ocedtues involving fleshy tissue such as muscle or bowel.
`particularly in bowel resection procedures. Circular cutting
`and stapling devices have succwsfully been used. for
`example.
`in anastotnotic procedures where a lumen is
`rejoined. However.
`the results with cutting and stapling
`devices have been less than optimum where the procedure
`involves cutting highly vascularized tissue. such as meson-
`tery or adneita, which are prone to having hemostasis
`problems.
`Elecuocautsery devices have also been used for effecting
`helnostasis. Monopolar devices utilize one electrode asso-
`ciated with a cutting or cautetizing instrument and a remote
`return electrode. usually adhered externally to the patient.
`
`2
`More recently. bipolar instruments have been used because
`the cautcrizing current is generally limited to tissue between
`two electrodes of the instrument.
`
`Bipolar forceps have been used for cutting andfor coagu-
`lation in various procedures. For example. bipolar forceps
`have been used in sterilization procedures where the fallo-
`pian tubes are settled ofl. Generally. bipolar forceps grasp
`tissue between two poles and apply electrical current
`through the grasped tissue. Bipolar forceps. however. have
`certain drawbacks. some of which include the tendency of
`the current to are between poles when tissue is thin or the
`forceps to short when the poles of the forceps touch. The use
`of forceps for coagulation is also very technique dependent
`and the forceps are not adapted to simultaneously caulerize
`a larger area of tissue.
`Bipolar scissors have been disclosed where two scissors
`blades act as nvo electrodes having insulated shearing
`surfaces. This device mechanically cuts tissue as coagulat-
`ing electrical current is delivered to tissue in the current
`path. Bipolar scissors are also highly technique dependent in
`their use.
`
`In prior devices. such as the device described in U.S. Pat.
`No. 5.403.312, clectrosurggical energy has been delivered to
`biologic tissue in order to create a region of coagulation. as.
`for example. on either side of an incision. thus preventing
`blood and other bodily fluids from leaking out of the
`incision. In such a device. if tissue grasped by the jaws is
`compressed too much by applying excessive pressure to the
`region of coagulation. the tissue grasped by the end effector
`may be torn or crushed. If the tissue is not compressed
`enough because to little pressure is applied to the region of
`coagulation. the tissue in the region of coagulation may not
`be not efiectively or uniformly cauterized because fluid (e.g.
`blood) could remain in the region of cauterization. In prior
`art devices. the strgeon has used tactile feedback and visual
`clues to determine the amount of pnessun: to apply to the
`region in order to obtain optimum coagulation. In instru-
`ments wherein the region of coagulation is partially or fully
`obscured. either by the end effector or by tissue, and is.
`therefore. not visible tothe surgeon. it is particularly diificult
`for the surgeon to ensure that the appropriate pressure is
`being applied by the end effectors to ensure proper coagu-
`lation. It would, thaefore, be advantageous to develop an
`_ electrosurgical
`instrument wherein the surgeon is not
`required to adjust the pressure applied by the end effector
`prior to applying electrosurgical energy to tissue in the
`region of coagulation. It would further be advantageous to
`-design an instrument wherein the pressure applied to the
`tissue prior to coagulation is within a predetermined range.
`One lcnown method of varying the pressure applied to the
`tissue by the jaws of the end elfector involves varying the
`gap between the jaws depending upon the tissue being
`grasped. However. such an arrangement would necessitate
`the use of dilferent instruments. dilfettnt end elfcclors or
`dilfctent staple cartridges depending upon the tissue being
`grasped. It would, therefore, be advantageous to design an
`instnurtent wherein the pressure applied by the end eltector
`would vary with the thickness and makeup of the tissue
`being grasped.
`Non electrosurgical endocutters such as those described in
`U.S. Pat. No. 5.591.107, employ a. relatively stifl lower jaw
`member which includes a staple cartridge in conjunction
`withamote flexiblettpperrnembcrwhich actsasananvil
`against which the staples are fomied. In such insu-tunents.
`the anvil is generally ntanufactmed to be as stifas possible.
`within the limits of size. tnaterials and other design consid-
`
`14
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`

`
`3
`
`HL904
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`4
`
`erations and the spring rate of such an anvil may be. for
`example. in the range of 350-450 pounds per inch. A still"
`anvil helps to ensure that the staples form properly when the
`instrument is fired. Spring rate. in terms of tissue compres-
`sion forces in conventional staplers with gap spacing pins. is
`used in conjunction with the gap pin to create and maintain
`a minimum gap between the staple cartridge and the anvil.
`setting the height of the formed staple. Therefore.
`the
`designers of conventional stapling instruments with gap
`spacing pins are primarily interested in the formation of a
`simple beam with consistent gap to form consistent staples.
`In other designs. the gap pin is not used and the anvil is
`designed with suflicient stillness to facilitate the formation
`of tissue. It would. therefore. be advantageous to design an
`electrosurgical instrument where the spring rate of the anvil
`is sufliciently stiff for the formation of staples while exerting
`a pressure in a range which facilitates the proper cauten'za-
`tion of tissue.
`
`SUMMARY OF THE INVENTION
`
`It is therefore an object of the present invention to provide
`a hemostatic electrosurgical
`instrument which can exert
`pressure in a range to efficiently provide improved hemo-
`stasis in multiple tissue types and thickness. e.g.. in fleshy or
`vascular tissue areas. and high. low or combination imped-
`ance tissues. Hemostasis is used herein to mean generally
`the arresting of bleeding including by coagulation. camer-
`ization andfor tissue joining or welding.
`Another object of the invention is to provide an improved
`cutting and stapling device with an electrocautery means for ‘
`tissue welding or cauterization along a cutting path wherein
`the device is adapted to grasp tissue and exert a pressure
`within a predetermined range in order to provide improved
`hemostasis prior to cutting the tissue.
`These and other objects of the invention are described in '
`an electrosurgical device having an end effector with oppos-
`ing interfacing surfaces associated with jaws for engaging
`tissue therebetween. and two elecu-ically opposite poles
`located on one or both of the opposing surfaces. The poles
`are isolated from each other with an insulating material. or.
`where the poles are on opposite interfacing surfaces. they
`may be offset from each other so that they do not directly
`oppose each other on interfacing surfaces. In particular, an
`electrosurgical device according to the present invention
`includes a substantially fixed lower jaw. Fturher. an elec-
`trosurgical device according to the present
`invention
`includes a substantially flexible upper jaw having a spring
`rate in the range of between apptoxitnately 200 pounds per
`inch and approximately 600 pounds per inch. More
`particularly. the spring rate of the upper jaw is approxi-
`mately 275 pounds per inch.
`An electrosurgical instrument of a preferred embodiment
`compresses tissue to a pressure within a predetermined
`range in a compression zone between a first interfacing
`surface and a second interfacing surface and applies elec-
`trical energy through the compression zone. The first inter-
`facing surfacc is comprised of: a lirst pole of a bipolar
`energy source. which interfaces with the compressed tissue
`in the compression zone; and a second pole electrically
`isolated front the first pole and located on the same or
`opposite interfacing surface. Electrically isolated poles are
`defined herein to mean electrodes isolated from each other
`by an imulating material in the end effector andlor oflset
`from cad: other on opposing stnfaces.
`In a preferred embodiment. the compression zone is an
`area defined by a compression ridge on one of the interfacing
`
`the other
`surfaces which compresses the tissue against
`interfacing surface. Also. there may be a compression ridge
`on both interfacing surfaces. A coagulation none is defined
`by the first pole. the second pole, and an insulator insulating
`the first pole from the second pole. The second pole. located
`on one of the interfacing surfaces. is generally adjacent to
`the insulator on the same interfacing surface or across from
`the insulator on an opposing surface. This arrangement
`electrically isolates the two poles and enables the current
`path between the first and second poles to cross through a
`desired area of tissue.
`
`-
`
`It is believed that the tissue compression nonnalizes tissue
`impedance by reducing structural differences in tissue which
`can cause impedance differences. Compression also stops
`significant blood flow and squeezes out blood which acts as
`a heat sink. particularly when flowing through blood vessels.
`Thus. compression optimizes delivery of energy to tissue in
`part by enabling the rate of energy delivery to exceed the rate
`of dissipation due to blood flow. The arrangement of the
`electrodes. which make up the poles. is important to ensure
`that the current passing between the two poles passes though
`the compression zone. Also. insulation or isolation of the
`opposite poles from each other on the instrument pen-nits
`tissue compression without shorting of the instrument poles
`- or electrical arcing common in bipolar instruments.
`In one embodiment of the present invention. the pressure
`initially applied to tissue in the compression zone is between
`approximately 30 pounds per square inch (psi) and approxi-
`mately 250 psi. la a further embodiment of the present
`invention.
`the pressure initially applied to tissue in the
`compression zone is between approximately 75 psi and 250
`psi. In a further embodiment of the present invention. the
`pressure initially applied to tissue in the compression zone
`is between approximately US psi and I85 psi.
`Thus. the tissue compression and the arrangement of the
`electrodes permit more elificient cautciiaation and olfcr the
`advantage of achieving hemostasis in a wide range of tissue
`impedance. thickness and vascularity.
`In an alternative embodiment of the intention. the first
`pole is locatedon a first interfacing surface of a that jaw and
`the second pole is located on the same jaw as the first pole.
`but not on the interfacing surface.
`The present invention also provides a device capable of
`_ coagulating a line or path of tissue along or lateral to a cut
`line or a cutting path. In one embodiment, the first pole
`comprises an elongated electrode. The elongated electrode
`along with the adjacent insulator form a ridge to compress
`the tissue to be cauterized. The second pole is adjacent the
`insulator on an opposite side of the insulator from the llrst
`pole.
`
`'
`
`In one preferred embodiment. a cutting means for cutting
`tissue is incorporated into the device and the device provides
`hemostatic lines adjacent an-the path of the cutting means. Of
`course. caning may occur at anytime either before. during or
`after cauterizalzion or welding.
`In one variation of this
`preferred embodiment. stapling means is provided on one or
`both sides of the cutting path.
`In one embodiment. an indicator means communicates to
`the user that the tissue has been cauterizaed to a desired or
`predetermined degree.
`In another embodiment. the coagulation is completed
`prior to any mechanical cutting. i.e.. actuation of the cutting
`means. If an indicator means is used. once tissue is
`cauterized.
`the cutting means may be actuated to out
`between the parallel bars while the rows of staples are
`applied to the tissue.
`
`15
`
`

`
`Hl.904
`
`5
`In another embodiment. the hemostatic device is incor-
`porated into a linear cutter similar to a linear cutting
`mechanical stapler.
`In this embodiment
`the hemostatic
`device comprises two parallel and joined elongated elec-
`trode bars which form one pole. and a slot for a cutting
`means to travel between the bars. Optionally, one or more
`rows of staples may be provided on each side of the slot and
`bats to provide additional hemostasis. In operation. tissue is
`clamped between two jaws. Electrical energy in the form of
`radio frequency current is applied to the compressed tissue
`to cauterize the blood vessels along the two parallel bars.
`Another embodiment provides a means for detecting
`abnonnal impedance or other electrical paralneters which
`are out of a predetermined range. For example, the means for
`detecting may be used to indicate when the instrument has
`been applied to tissue exhibiting impedance out of range for
`anticipated good coagulation. It may also be used for detect-
`ing other instrument abnormalities. II is possible to detect
`the abnormal condition. for example. by using comparisons
`of normal ranges of initial tissue impedance in the interface
`electronics. This could be sensed in the first few millisec-
`onds of the application of RF energy and would not present
`a significant therapeutic dose of energy. A warning mecha-
`nism may be used to warn the user when the impedance is
`out of range. Upon repositioning of the instrument. the same
`rneasurement criteria would apply and if the tissue imped-
`ance was again out of range, the user would again be
`warned. This process would continue until
`the aroma!
`impedarrcc range was satisfied and good coagulation could
`be anticipated.
`Sinrilarly another embodiment provides a tissue welding
`and cautcrizing cutting device similar to an intralumina]
`stapler. Preferably. the poles are formed in two concentric
`circle electrodes separated by an insulator. The electrodes
`which make up the poles may be located on either the stapler -
`cartridge or the anvil.
`These and other objects of the invention will be better
`understood from the following attached Detailed Descrip-
`tion of the Drawings. when taken in conjunction with the
`Detailed Description of the invention.
`
`DETAILED DESCRIPTION OF THE DRAWINGS
`
`FIG. I is a side elevational view of an endoscopic
`electrocatrtery linear stapling and crnting instrument of one
`etrtbodinrent of the present invention;
`FIG. 2 is a side cross sectional view of the instrument of
`FIG. 1:
`FIG. 3 is a partial cross sectional view of the distal end of .
`the instrument of FIG. I in an open position;
`FIG.-Iisapartialcrosssectionalviewofthcdistalcndof
`the instrument of FIG. I in a closed. unlired position:
`FIG. 5 is a partial cross sectional view of the distal end of
`the instrument of FIG. 1 in a closed. fired position:
`FIG. 6 is a front cross sectional view of the distal end of 55
`the instrument of FIG. 3 taken along the line 6-6:
`FIG. 7 is a bottom isolated view of the anvil jaw of tire
`instrument of FIG. I;
`FIG. 8 is a top isolated view of a cartridge of the
`instrument of FIG. 1:
`
`FIG. 9 is a side cross sectional view of the jaw of FIG. 7
`along the line 9-9;
`'
`FIG. I0 is a how chart illustrating a feedback system of
`the present invention;
`FIG. 11 is a front cross sectional view of the end elfector
`of another embodiment of the present invention;
`
`6
`FIG. I2 is a front cross sectional view of the end effector
`of another embodiment of the present invention:
`FIG. 13 is a front cross sectional view of the end cffcclor
`of another embodiment of the present invention:
`FIG. 14 is a front cross sectional view of the end elfector
`of another embodiment of the present invention;
`FIG. 15 is a bottom isolated view of the anvil of another
`embodiment of the present invention:
`FIG. 16 is a bottom isolated view of the anvil of another
`embodiment of the present invention:
`FIG. 17 illustrates a cross sectional view of the distal end
`of another embodiment of the present invention:
`FIG. 13 is front cross sectional view of the end effector of
`FIG. 17:
`FIG. 19 is a front cross sectional view of the end efiector
`of another embodiment of the present invention:
`FIG. 20 is atop view of a cartridge of a circular cutter of
`the present invention;
`FIG. 21 is a bottom view of the anvil of a circular cutter
`of the present invention.
`FIG. 22 is a cross sectional view of the end effector
`according to a further embodiment of the present invention.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`Referring now to FIGS. l—9. there is illustrated a pre-
`ferred embodiment of the present invention. An endoscopic
`electrocaulery linear cutting and stapling instrument It} is
`shown having a body 16 coupled to it shall 30 with a lumen
`extending thcretlrrough and an end effector 50 extending
`from the distal end 21 of the shaft 30. The shaft 30 is formed
`of an insulative material and has an electrically conductive
`sheath 38 extending through its lumen. A channel 39 extend-
`ing through the sheath 38 guides co-axial movement of a
`driver means 44 within the channel 39. In this particular
`embodiment. the driver means 44 includes a firing nigger 14
`associated with the body 16. coupled to a flexible firing rod
`40 coupled to a driving rod 41. coupled no a block 43. The
`block 43 is coupled to a cutting mean 11 and a staple
`driving wedge 13. which the driving means 44 advances by
`way of the block 43 into the end elfector S0.
`
`The end eliector 50 comprises two interfacing jaw mem-
`bers 32. 34. The end eflector 50 is secured by way of jaw
`member 34 to the channel 39. The jaw rnetnbcr 32 is
`movably secured to jaw member 34. The body 16 has a
`clamping trigger 12 for closing the jaws 32. 34 which
`longitudinally advances a close rack 45 coupled to the
`proximal end of the sheath 38. The close rack 45 advances
`the sheath 38 co-axially through the shaft 30. The sheath 38
`advances over a cumming srnface 27 of jaw 32 to close the
`jaws 32 and 34 onto tissue situated between the jaws. As
`described in more detail below. the close rack 45 also act:
`as a switch to close the circuit which communicates elec-
`trical energy to the end elfector 50.
`Referring now to FIGS. 3-9 and 22 an enlargement of the
`end elfector 50 of the Instrument 10 is illustrated. The jaw
`members 32 and 34 are shown in mi unclamped position in
`FIG. 3, in a clamped. unfired position in FIG. 4 and in a
`clamped. tired position in FIG. 5. law member 32 comprises
`an anvil 18. a U—shapcd first pole 52 extending longitudi-
`nally with respect to the jaw 32, and a U-shaped insulating
`material 55 sturorurding the outside of the first pole 51. law
`me-mber32 has anirurersurface33 whichfaces aninner
`surface 35 ofjaw 34. The irurer surface 33 Includes first pole
`52 which comprises two electrically communicating elec-
`
`16
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`7
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`HL904
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`trode bars 53. 54 comprised of stainless steel or aluminum.
`extending substantially along the length of the inner surface
`33. The bars 53. 54 are separated by a knife channel 42
`extending longitudinally through the first po|e's center to
`form its U—shape. The surface of the bars are forntcrl in flat
`strips to provide more surface area Contact with tissue. Two
`series of pockets 36, 37 located on anvil 18. for receiving
`staple ends. extend along tlte inner surface 33. lateral to and
`outside of bars 53. 54 respectively. The electrode bars 53.54
`and the insulating material 55 form a ridge 56 extending out
`relative to the anvil portion 33a of the inner surface 33 (FIG.
`ti}. The anvil 18 is formed of an electrically conductive
`material and acts as a second pole electrically opposite to the
`fit-st pole. The anvil 18 is isolated from the first pole 52 by
`the U-shaped insulating material 55.
`Jaw member 34 comprises a cartridge channel 22 and a
`cartridge 23. The cartridge 23 includes a track 25 for the
`wedge 13. knife channel 26 extending longitudinally
`through the center of the cartridge 23, a series of drivers 24
`extending into track 25 and staples I00 arranged in two sets
`of parallel double rows. When tissue is engaged between the
`jaws 32. 34. the driver means 44 may be actuated or fired
`using trigger 14 to advance the cutting means H and wedge
`13 through the engaged tissue to staple and cut the tissue.
`When the firing mechanism 14 is actuated. the wedge 13 is
`advanced through the track 25 causing the drivers 24 to
`displace towards the staples lllll. thereby driving the staples
`100 through tissue and into anvil pockets 36. 37.
`In the embodiment of the invention illustrated in FIG. 22.
`dimension B. which is measured front inner surface 33 of '
`jaw member 32 to tissue surface 8-0 of U-shaped insulating
`material 55. is preferably in the range of from approximately
`0.0 inches to approximately 0.045 inches and preferably
`approximately 0.0 inches. Dimension C. which is measured
`front inner edge 82 to outer edge 84 of U-shaped insulator "
`55 along tissue surface 80. is preferably in the range of from
`approximately 0.01 inches to approximately 0.04 inches and
`preferably approximately 0.02 inches. Dimension E. which
`is measured from inner edge 86 to outer edge 88 of first pole
`52 as measured along tissue surface 90. is preferably in the
`range of from approximately 0.002 inches to 0.04 inches and
`preferably approxirnately 0.020 inches. Dimension G. which
`is measured from tissue stu-face 90 to tissue surface 92 with
`jaws 32 and 34 closed.
`is preferably in the range from
`approxirrtately 0.0 inches to approximately 0.020 inches and
`preferably approximately 0.00]
`inches. Dimension (3 is
`measured without tissue engaged.
`A knob 15 located on the distal end of the body 16 rotates
`the shaft 30. sheath 38, channel 39 and end etfector-Sti which
`are directly or indirectly coupled to the 1-mob 15 so that the
`knob 15 may be used for rotational placement of the end
`effector jaws 32.34.
`Bipolar energy is supplied to the end elfector 50 from an
`- electrosurgical generator 60 through when 19. Zllcxtending _
`into the body 16 of the instrument. The generator 60 is user
`controlled by way of a footswitch 65.
`Wire 19 which provides electrical current to the first pole,
`is coupled through a wire or other electrical contact means
`61 to electrical contact 62. associated with the first pole.
`located on the distal end of close rack 45. Wire 20 which
`carries the current of the opposite pole. is coupled through
`It wire or other electrical contact It:-carts 66 to it disc contact
`67 located at
`the distal end of the close rack 45 and
`electrically isolated from contact 62.
`A disc contact 63. associated with the first pole. located at
`the distal end of the body 16 is in electrical communication
`
`8
`with a wire or other Contact means 64. Contact means 64
`extends through channel 39 to end elfector jaw 32 where it
`contacts first pole S2. The disc contact 63 permits the knob
`15 to rotate while contact
`is maintained between the disc
`Contact 63 and the contact means 64. The contact means 64
`is electrically insulated from the sheath 38.
`When tlte clamping trigger 12 is actuated. the close rack
`45 moves distally so that the contact 62 comes in electrical
`communication with the disc Contact 63 and the disc contact
`67, associated with the second pole 51. comes in electrical
`contact with the electrically conductive sheath 38. The
`sheath 33 moves over the camming surface 27 of the
`electrically conductive anvil 18 which acts as the ren.trn
`electrode. Thus the electrical circuit is closed when and only
`when the clamping trigger 12 is closed.
`is
`In operation. the end elfector 50 of the instrument
`located at a tissue site where tissue is to be cut. The jaw
`members 32. 34 are opened by pressing a release button 70
`which releases a button spring 71 and permits the close rack
`45 to move prortimally. Tissue is then placed between the
`interfacing inner surfaces 33. 35 respectively of the jaw
`members 32. 34. The clamping trigger 12 is squeeaed to
`cause the sheath 38 to move over the carruning surface 2'?
`and thereby close the jaws 32, 34 and simultaneously close
`the electrical circuit as described above. The electrode bars
`' 53. 54 and the insulating material 55. which together form
`the ridge S6. compress the tissue against the inner surface 35
`ofjaw member 34. A user then applies RF energy from the
`generator 60 using the footswitch 65 or other switch. Current
`flows through the compressed tissue between the first pole
`52. i.e. the bars 53, 54, and the second pole S1. i.e.. the anvil
`18.
`
`In one embodiment of the present invention the initial
`pressure applied to compress the tissue in the compression
`zone is between approximately 30 pounds per square inch
`(psi) and 250 psi. More particularly. in a further embodiment
`of the present
`invention the initial pressure applied to
`compress the tissue in the compression zone is between
`approximately 75 psi and 250 psi. More pa.rticula.rly in a
`further emhorlirnent of the present
`invention the initial
`pressure applied to compress the tissue in the compression
`zone is between approximately 75 psi and 175 psi. in one
`embodiment of the present invention. the initial pressure
`applied to compress tissue positioned between the jaws is
`approximately I25 psi. With suflicient pressure applied
`fluid.
`including blood. is forced out of the tissue in the
`compression mite. facilitating coagulation. In addition. pres~
`sure applied to tissue within the compression zone facilitates
`coupling of electrosurgical energy to the tissue by forcing
`the tissue against the electrode.
`is it ftutctiort of the
`The pressure exerted by the anvil
`spring rate of the anvil. By providing a “pre-bertd" angle on
`the anvil it is possible to obtain a pre-load [at a zero gap.)
`Thus. where it pre-bend angle is applied. the anvil may be
`viewed as a prestressed beam. A Preferred value of pteload
`is in the range of between 12 and 13 pounds with a preferred
`value of approximately l5 pounds. The spring rate of the
`anvil is more accurately it function of the stiffness of the
`“system”. where the system includes the anvil. cha