US20060195083A1 - Electrosurgical hemostat - Google Patents

Abstract

A hemostat-type device for ablative treatment of tissue, particularly for treatment of atrial fibrillation, is constructed with features that provide easy and effective treatment. A swiveling head assembly can allow the jaws to be adjusted in pitch and roll. Malleable jaws can permit curved lesion shapes. A locking detent can secure the jaws in a closed position during the procedure. An illuminated indicator provides confirmation that the device is operating. A fluid delivery system simplifies irrigated ablation procedures.

Description

RELATED U.S. APPLICATION DATA
• This application claims priority from U.S. Provisional Patent Application No. 60/422,330 filed Oct. 30, 2002, incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
• The present invention relates to surgical tools and procedures generally and relates more particularly to the use of electrosurgical ablation to treat atrial fibrillation.
• In patients with chronic atrial fibrillation or having atrial tachycardia that is resistant to medical treatment, the Maze III procedure has been employed. This procedure controls propagation of the depolarization wavefronts in the right and left atria by means of surgical incisions through the walls of the right and left atria. The incisions create blind or dead end conduction pathways, which prevent re-entrant atrial tachycardias from occurring. While the Maze procedure is successful in treating atrial fibrillation, the procedure is quite complex and is currently practiced by only a few very skilled cardiac physicians in conjunction with other open-heart procedures. The procedure also is quite traumatic to the heart, as in essence the right and left atria are cut into pieces and sewed back together, to define lines of lesion across which the depolarization wavefronts will not propagate.
• It has been suggested that procedures similar to the Maze procedure could be instead performed by means of electrosurgical ablation, for example, by applying radiofrequency (RF) energy to internal or external surfaces of the atria to create lesions across which the depolarization wavefronts will not propagate. Such procedures are disclosed in U.S. Pat. No. 5,895,417, issued to Pomeranz, et al., U.S. Pat. No. 5,575,766, issued to Swartz, et al., U.S. Pat. No. 6,032,077, issued to Pomeranz, U.S. Pat. No. 6,142,944, issued to Swanson, et al., U.S. Pat. No. 5,871,523, issued to Fleischman, et al. and U.S. Pat. No. 6,502,575, issued to Jacobs et al., all incorporated herein by reference in their entireties. Hemostat type, electrosurgical or cryo-ablation devices for use in performing such procedures are described in U.S. Pat. No. 5,733,280 issued to Avitall, U.S. Pat. No. 6,237,605 issued to Vaska, et al, U.S. Pat. No. 6,161,543, issued to Cox, et al., PCT published Application No. WO99/59486, by Wang and in pending U.S. patent application Ser. No. 09/747,609 filed Dec. 22, 2000 by Hooven, et al., all incorporated herein by reference in their entireties. In order for such procedures to be effective it is desirable that the electrosurgically created lesions are continuous along their length and extend completely through the tissue of the heart (i.e. transmural lesions). These goals may be difficult to accomplish employing dry ablation electrodes or electrodes applied only to the interior or exterior surfaces of the heart tissue. Electrosurgical hemostats configured to allow fluid-assisted tissue ablation are generally described in U.S. Pat. No. 6,096,037, issued to Mulier, also incorporated by reference in its entirety.
SUMMARY OF THE INVENTION
• The present invention provides an ablation hemostat, particularly useful in performing a maze type procedure by applying ablation energy (e.g. RF energy) across the walls of the left and right atria by means of delivery means located on either side of the atrial walls. In a preferred embodiment of the invention, the hemostat is provided with elongated RF electrodes malleable to assume various straight and curved configurations to produce lesions that approximate the incisions that would occur during the Maze III procedure as described in the book ‘Cardiac Surgery Operative Technique’ by Donald B. Doty, M.D. at pages.. 410-419, incorporated herein by reference in its entirety, or to allow creation of lines of lesion corresponding to the incisions that would be provided by other forms of the Maze procedure. The hemostat may be useful in conjunction with other procedures as well.
• The hemostat of the present invention is provided with a number of useful features, particularly adapted to ease its use in conjunction with creating elongated lines of lesion. While the disclosed and most preferred embodiments of the invention employ all of the improved features, each of the improved features discussed below is believed valuable in and of itself to improve the performance and ease of use of prior art electrosurgical hemostats.
• In order to allow the hemostat to produce straight and curved elongated lesions, the jaws of the hemostat are malleable to allow the physician to set the specific jaw configuration. The jaws are fabricated of a flexible plastic sheath enclosing elongated bendable or malleable backbones and electrodes to achieve this result. The backbones and electrodes may be shaped by the physicians ' fingers into a desired curvature and serve to retain the curvature imparted to them until reshaped for creation of a subsequent lesion. The backbones take the form of elongated plates having thicknesses substantially less than their widths to encourage bending of the jaws within a single plane so that the opposed electrodes can more readily be maintained in alignment along their lengths. The backbones are also preferably tapered along their length such that the width of the backbones diminishes as they approach the tips of the jaws, in turn making it easier to provide the jaws with the curvature extending over the entire length of the jaws.
• The hemostat includes an elongated handle portion or handle and a jaw assembly mounted at the distal end of the handle. The jaw assembly preferably includes two elongated jaws carrying RF electrodes or other ablation elements, extending along the lengths of the jaws and arranged so that they are located on opposite sides of tissue compressed between the jaws. In preferred embodiments, the electrodes take the form of fluid irrigated RF electrodes, however, other ablation mechanisms such as cyroablation, direct current ablation, microwave ablation, and the like may be substituted for RF ablation electrodes.
• The jaw assembly preferably includes a swiveling head assembly adapted to allow the jaws to be rotated relative to the axis of the handle (roll) and allowing the jaws to pivot around an axis perpendicular to the axis of the handle (pitch). Adjustment of the jaws relative to the handle (pitch and roll) is made manually by the physician, and the jaws are retained in their desired orientation relative to the handle by means of detent mechanisms.
• The jaws are mounted to one another at a pivot point and are opened and closed by means of a trigger, mounted to the handle, which applies. tensile force to a cable or other tension member extending along the handle. The cable, when pulled, pulls the jaws toward one another to compress tissue between them. In the particular embodiments disclosed, the cable is anchored offset from the pivot point to a first one of the jaws. The first jaw is fixed, i.e. retains its location during jaw closure regardless of the pitch and roll adjustment made to the jaw assembly. The second, pivoting jaw, is mounted to the fixed jaw at a pivot point and the cable passes around an internal boss within the pivoting jaw, also offset from the pivot point. Application of tension to the tension member pulls the internal boss in the pivoting jaw toward the cable mounting point in the fixed jaw and thereby causes movement of the jaws toward one another. Tissue placed between the jaws can thus be engaged by the jaws and compressed between the jaws as the jaws close.
• The cable enters the jaw assembly along its rotational (roll) axis, so that rotation of the jaw assembly about the roll axis does not alter the operation of the cable. The cable extends around a shoulder internal to the fixed jaw, which shoulder remains essentially in the same location regardless of the pitch adjustment of the jaw assembly, so that pitch adjustment of the jaw assembly does not significantly effect operation of the cable to close the jaws.
• In preferred embodiments, the trigger mechanism is provided with a locking detent mechanism which may be engaged or disengaged and which, when engaged, retains the trigger in its position, in turn maintaining compression of the jaws against tissue located there between. The detent mechanism in a preferred embodiment is activated or deactivated by means of a sliding button, mounted to the handle.
• In preferred embodiments, irrigation fluid is provided to the electrodes by means of plastic tubing that is provided with in-line flow limiters, controlling the delivery rate of irrigation fluid to the electrodes. This feature allows the use of a simplified fluid pumping mechanism and also provides balanced, even fluid flow to the electrodes. In its preferred embodiment, the trigger, when released, also serves to block fluid flow to the electrodes, preventing irrigation while the hemostat is not in use.
• In one embodiment, the RF electrode assembly can take the form of an elongated porous material coupled to the fluid delivery lines and carrying elongated electrode wires on their inner, facing services. The electrode wires may be coupled to the porous material by means of a series of spikes extending from the electrode wires into the porous material. Other alternative electrode designs may of course be substituted, including electrodes comprised of elongated coil electrodes or perforated tubular electrodes with porous material located either inside of or surrounding the electrodes. For example, a perforated tubular electrode can be seated inside a porous polymeric support such the electrode is entirely within the support. In this embodiment, conductive fluid flows through the interior of the electrode, out of perforations in the electrode and through the porous support to facilitate ablation such that the polymeric support, not the electrode, is on the facing surfaces of the jaws to contact the tissue to be ablated.
• The hemostat may optionally also include a thermocouple, located along the jaws allowing for temperature controlled feedback of power provided to the RF electrodes and may also preferably includes an indicator LED mounted to the handle, activated to indicate that delivery of RF energy is underway. The hemostat is usable useable with conventional RF generators. Alternatively, the hemostat may be used in conjunction with an RF generator system, which incorporates a transmurality measurement and automatic shut off of ablation energy.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a plan view of an assembled hemostat according to one embodiment of the present invention.
• FIG. 2 is an exploded view of the jaw assembly of the hemostat ofFIG. 1.
• FIG. 3A is a cross-section view through the jaw assembly of the hemostat ofFIG. 1.
• FIG. 3B is a cross-section view throughlines3B-3B ofFIG. 3A.
• FIG. 4 is an end view in partial cross-section of the proximal end of the knuckle portion of the jaw assembly of the hemostat ofFIG. 1.
• FIG. 5A is a plan view of an elongated tubular electrode used in the hemostat ofFIG. 1.
• Figure 5B is an enlarged cross-section view taken alonglines5B-5B of the electrode illustrated inFIG. 5A.
• FIG. 6A is an end view of an electrode support as used in the jaw assembly of the hemostat ofFIG. 1.
• FIG. 6B is a cross-section view taken along lines6A-6A ofFIG. 6A illustrating the electrode support.
• FIG. 7A is an end view of an electrode sheath as included in the jaw assembly of the hemostat ofFIG. 1.
• FIG. 7B is a cross-section view taken alonglines7B-7B ofFIG. 7A illustrating the electrode sheath.
• FIG. 8A is a plan view of the right half of the handle employed in the hemostat ofFIG. 1.
• FIG. 8B is an enlarged plan view of the distal portion of the right handle half illustrated inFIG. 8A.
• FIG. 8C is a cross-section view taken alonglines8C-8C through the right handle half of the hemostat ofFIG. 1.
• FIG. 9A is a plan view of the left half of the handle employed in the hemostat ofFIG. 1.
• FIG. 9B is an enlarged plan view of the distal portion of the left handle half illustrated inFIG. 9A.
• FIG. 9C is a cross-section view taken alonglines9C-9C through the left handle half of the hemostat ofFIG. 1.
• FIG. 10 is an enlarged view of the trigger portion of a hemostat as inFIG. 1 with the left handle half removed.
• FIG. 11A is a perspective view of a trigger lock as employed in the trigger assembly of the hemostat as inFIG. 1.
• FIG. 11B is a plan view of the trigger lock ofFIG. 11A.
• FIG. 12A is a top plan view of a link arm as employed in the trigger assembly of an assembled hemostat as inFIG. 1.
• FIG. 12B is a side plan view of the link arm ofFIG. 12A.
• FIG. 13A is a side plan view from the distal end of the trigger employed in the trigger assembly of the hemostat ofFIG. 1.
• FIG. 13B is a cross-section view taken alonglines13B-13B through the trigger ofFIG. 13A.
• FIG. 14 is a cut-away view of the proximal portion of the hemostat ofFIG. 1 with the left handle half removed. pFIG. 15A is a sectional view through an alternative embodiment of an upper and lower jaw for use with a hemostat otherwise as inFIG. 1.
• FIG. 15B is a cross-sectional view taken alonglines15B-15B ofFIG. 15A.
• FIG. 16A is a plan view of an electrode extension employed in the alternative embodiment of the upper and lower jaw depicted inFIGS. 15A and 15B.
• FIG. 16B is an expanded view of a barb of the electrode extension depicted inFIG. 16A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• In reference toFIG. 1, a preferred embodiment of the hemostat of the present invention generally comprises an elongated handle assembly or handle10 having ajaw assembly90 mounted at handledistal end15, atrigger20 intermediate the handle proximal anddistal ends95 and15, and astrain relief60 located at handleproximal end95. An elongated cable is coupled to thestrain relief60 and comprises afluid conduit70 extending to a proximal fluid fitting75 adapted to be coupled to a source of conductive fluid and a multi-conductorelectrical cable80 extending to a proximalelectrical connector85 adapted to be coupled to an electrosurgical unit. Thetrigger20 is employed to move the jaws of the first orlower jaw assembly40 with respect to the second orupper jaw assembly30 of thejaw assembly90 together to compress tissue therebetween to allow for creation of a linear RF ablation by electrically conductive fluid emitted from electrodes and contacting tissue or direct contact of the electrodes located along the upper andlower jaws35 and45.
• Thejaw assembly90 includes theupper jaw assembly30, thelower jaw assembly40, and aswivel assembly50, discussed in more detail below. The upper jaw andlower jaw assemblies30 and40 have opposed upper andlower jaws35 and45, respectively, each comprising a fluid assisted elongated electrode assembly. The upper andlower jaw assemblies30 and40 support elongated electrodes, discussed in more detail below, each coupled to one of the insulated conductors withinconduit70 extending proximately through thestrain relief60 toelectrical connector85. Each of thejaws35 and40 of respective upper andlower jaw assemblies30 and40 are also coupled tofluid conduit80 enabling delivery of saline or other conductive fluid from a source coupled to fitting75 along the lengths of theopposedjaws35 and45.
• Theswivel assembly50, provides the physician with the opportunity to position thejaw assembly90 in a variety of orientations relative to thehandle10, to facilitate placing the35 and45 jaws against tissue to form desired lines of lesions, e.g., the heart wall in performance of the above-described Maze procedure. The physician can manually grasp and rotate theswivel assembly50 and thejaw assembly90 to provide a roll adjustment R, preferably through an arc of at least 300 degrees, relative to the axis of thedistal end15 of thehandle10 through interaction of components of the handle and swivel assembly described further below. In addition, the physician can grasp thejaw assembly90 and adjust it in pitch P relative to theswivel assembly50 through the interaction of components of thejaw assembly90 and theswivel assembly50 described further below. Preferably, the available arc of pitch P adjustment extends over at least 90 degrees. Moreover, the upper andlower jaws35 and45 are malleable as described further below. The combination of these features and the S-shape handle10 make the hemostat highly versatile in use.
• Thetrigger20 is employed to open (separate apart) and close (draw together) thejaws35 and45 and to compress tissue between thejaws35 and45 prior to application of RF energy to create an elongated lesion. Athumb slide25 is provided in conjunction with an internal trigger lock, allowing the position of thetrigger20 and thejaws35,45 to be locked. After thetrigger20 is drawn toward thehandle10 to close thejaws35 and45, thethumb slide25 is moved distally relative to thehandle10 to cause an internal trigger lock to engage one of a series of ratcheting lock points that define a set of locking locations for thejaws35,45, as described further below. Movement of thethumb slide25 proximally relative to thehandle10 releases thetrigger20 and thejaw assembly90, allowing thejaws35,45 to return to a fully open position. The interaction of the trigger20,thumb slide25 and the associated trigger lock mechanism frees the physician from the need to maintain pressure on thetrigger20 to compress tissue between thejaws35,45 during the ablation, simplifying operation of the hemostat.
• Referring toFIG. 2, theupper jaw assembly30 includes a pivotable, relatively rigid,upper jaw mount300, anelongated backbone310, an elongatedinsulated electrode sheath320, an elongatedconductive electrode330, and anelongated electrode support340.Upperjaw mount300 may be fabricated of plastic or other insulated material, and in preferred embodiments may be fabricated of Teflon filled polycarbonate plastic.Backbone310 is preferably fabricated of malleable stainless steel or other malleable metal and is attached at a proximal end toupper jaw mount300. Aninsulated electrode sheath320 is fitted overspine310 with its proximal end located adjacentupper jaw mount300. The elongatedconductive electrode330 comprises a length of malleable conductive metal tubing as shown inFIGS. 5A and 5B is fitted into a lumen of theelongated electrode support340. Theinsulated electrode sheath320 is formed with a channel that receives the sub-assembly of the elongatedconductive electrode330 andelectrode support340 disposed along thejaw35.Electrode sheath320 may be fabricated of a flexible, electrically insulating, material, for example, silicone rubber.Elongated electrode support340 is preferably fabricated of a porous material, such as Porex™ plastic, allowing for conductive fluid infiltration through its sidewall along its length and correspondingly delivery of conductive fluid along the length ofjaw35. Thejaw35 can therefore be bent laterally with respect to theupper jaw mount300 to form a curve along the length thereof.
• Thelower jaw assembly40 also includes a relatively rigid,lower jaw mount400, anelongated backbone410, an elongatedinsulated electrode sheath420, an elongatedconductive electrode430, and anelongated electrode support440 that are all formed of the same materials as the corresponding elements of theupper jaw assembly30. The assembly of theelongated backbone410, elongated insulatedelectrode sheath420, elongatedconductive electrode430, andelongated electrode support440 is also shown inFIG. 3B.
• Thejaw45 can therefore also be bent laterally with respect to thelower jaw mount400 to form a curve along the length thereof. In use, the physician manually forms a lateral curve in both the upper andlower jaws35 and45 to fit the contour of the tissue, e.g., the heart wall.
• Thelower jaw mount400 is formed with a pair of spaced apart, parallel, plates orflanges401 and403 each bearing a series ofnotches402 and404, respectively, along the edges thereof. When assembled, a proximal portion of theupper jaw mount300 is fitted between theflanges401 and403. Apin480 extends through aligned holes through the proximal portion ofupper jaw mount300 and theflanges401 and403. The ends ofpin480 are fixed to theflanges401 and403 allowing the proximal portion of theupper jaw mount300 to be rotated about thepin480, thereby allowingjaws35 and45 to open and close. The upper andlower jaws35 and45 are separated apart a predetermined distance in the fully closed positions although the electrically insulated distal ends of theinsulated electrode sheaths320 and420 may contact one another. Aspring450 urges the upper andlower jaws35 and45 apart from one another, facilitating opening of thejaws35 and45 upon release of thetrigger20 after application of RF energy.
• As shown inFIGS. 2 and 3A, theswivel assembly50 includes aswivel500 that may also be fabricated of Teflon filled polycarbonate plastic to have a tubularproximal swivel portion506, a pair of parallel plates orflanges502 and504 extending distally from swivelproximal portion506 and a extendingdetent501 extending laterally betweenflanges502 and504. Thejaw assembly90 is mounted to theswivel assembly50 by outwardly and laterally extending bosses405 on the outer surfaces offlanges401 and403 that are fitted into bores503 throughswivel flanges502 and504. Theupper jaw mount300 is mounted to thelower jaw mount400 bypin480 as described above, and the lower jaw mount is400 pivotably mounted relative to theswivel500. Therefore, the upper andlower jaw assemblies30 and40 may be pivoted together relative to theswivel500, allowing for movement of thejaws35 and45 together through the range of pitch P adjustment. The selected pitch P adjustment is maintained by the engagement of thedetent501 into an opposed pair ofnotches402 and404, stabilizing the upper andlower jaws35 and45 in a desired orientation relative to theswivel assembly50. In use, the physician adjusts the relative positions of thejaws35 and45 relative to theswivel assembly50 by simply manually moving thejaw assemblies30 and40 in the pitch P direction around the pivot axis defined by bosses405 within the correspondingbores505 inswivel flanges502 and504. Thedetent501 simply rides over the ridges separatingadjacent notches402 and404.
• As noted above, theswivel assembly50 and the upper andlower jaw assemblies30 and40 can be rotated around the axis of thedistal end15 of thehandle10 to a desired roll adjustment R to facilitate positioning thejaws35 and45 for creation of elongated lesions. Theproximal portion506 ofswivel500 is rotatably mounted within a collar550 that is mounted fixedly to thedistal end15 of thehandle10 as shown inFIG. 3A. The collar550 has a wavy or sinusoidal distally facingsurface551 of collar550. A washer-shapedinsert510 having a wavy or sinusoidal proximally facingsurface511 is fitted over the elongatedproximal portion506 ofswivel500 and attached to theswivel500 throughnotches514, engaging correspondingbosses557 and567 (shown inFIG. 4) formed onswivel500. A C-clip524 mounted in a circumferential groove formed in theproximal portion506 ofswivel500 maintains theproximal portion506 within the lumen of collar550. Aspring washer522 and aflat washer520 are interposed between the C-clip524 and the proximal end of collar550.Spring washer522 urges the wavy or sinusoidal surfaces of collar550 and insert510 against one another, whereby a plurality of detent locations are defined that maintain a selected roll R adjustment relative to thedistal end15 of thehandle10. In use, the physician adjusts the roll R of thejaw assembly90 by simply turning theswivel assembly50 relative to thehandle10. The detent mechanism maintains theswivel assembly50 in the selected desired roll R adjustment prior to and during closure of thejaws35,45 to compress tissue during application of RF energy.
• Acable390 is also shown inFIGS. 3A and 4 that extends from thetrigger20 and that is employed to open and close thejaws35 and45.Cable390 passes through the internal lumen ofproximal swivel portion502, throughcable bore565, aroundshoulder404 oflower jaw mount400, aroundboss303 inupper jaw mount300 and then upward intobore408 inlower jaw mount400. The distal end of thecable390 is maintained withinbore408 byball350. When thecable390 is pulled proximally by squeezingtrigger25,boss303 ofupper jaw300 is pulled towardbore408 inlower jaw400, thereby pullingupper jaw35 towardlower jaw45, allowing for compression of tissue there between. It should be noted that during this operation, thelower jaw mount400 remains fixed relative to theswivel assembly50 and onlyupper jaw mount300 moves relative to theswivel assembly50 or thehandle10. Proximal movement of cable380 does not affect the position of thelower jaw45 relative to thehandle10, nor does it affect the selected roll R adjustment ofswivel500. Rotation of thejaw assembly90 and swivel500 about the roll axis does not affect the operation of thecable390 because thecable390 passes through theswivel500 and enters thejaw assembly90 along the roll axis. Pitch P adjustment of thejaw assembly90 does not significantly effect operation of thecable390 in opening or closing thejaws35,45 becauseshoulder404 is at the center of rotation oflower jaw mount400 relative to swivel500 and remains essentially in the same location regardless of the pitch P adjustment.
• FIGS. 3A and 4 also internal electrical wiring and fluid delivery conduits of this embodiment of the invention including,insulated conductors360 and460 andfluid conduits370 and470 that both terminate at connections with the proximal ends of the upper andlower electrodes330 and430, respectively. Thefluid conduits370 and470 deliver conductive fluid into the lumens of the tubular upper andlower electrodes330 and430, respectively. As shown inFIG. 4, the upperinsulated conductor360 and the upperfluid conduit370 are routed to one side of thecable390, and the lowerinsulated conductor460 and thelower fluid conduit470 are routed to the other side of thecable390 while passing through thelumen534.
• The elongatedtubular electrodes330 and430 are illustrated inFIGS. 5A and 5B. Thetubular electrodes330 and430 are preferably formed of thin-walled, malleable stainless steel tubing extending between a proximal open end331,431 and a distal closed end333,433. A series of fluid ports335,435 are formed, e.g., by laser drilling, through the sidewall of the tubing from the lumen339,439 and extending in a single line, although the fluid ports could be formed in any selected array extending around the circumference of the sidewall of the tubing. The proximal ends331,431 are notched in alignment with the series of fluid ports335,435 to assist in assembly so that the fluid ports335,435 are directed in a particular alignment with theporous electrode support340,440.
• Theporous electrode support340,440, depicted inFIGS. 6A and 6B, comprises a length of non-conductive, porous, malleable tubing having a channeled side343,443 adapted to fit within an elongated channel323,423 of theinsulated electrode sheath320,420, depicted inFIGS. 7A and 7B. Theporous electrode support340,440 is conically shaped at the support distal end347,447 to fit within a conically shaped terminus327,427 of the elongated channel323,423 of theinsulated electrode sheath320,420. During assembly, the elongatedtubular electrode330,430 is inserted into the elongated lumen341,441 of theporous electrode support340,440. Preferably, the series of fluid ports335,435 are oriented toward the channeled side343,443 so that the conductive fluid emitted from the lumen through the series of fluid ports335,435 then migrates laterally through the pores of theporous electrode support340,440 and around its circumference to thoroughly and uniformly wet theporous electrode support340,440 along the upper andlower jaws35 and45.
• The sub-assembly so formed is fitted into the shaped terminus327,427 and the elongated channel323,423 of theinsulated electrode sheath320,420 as also shown inFIGS. 3A and 3B. Adhesive is applied to the contacting surfaces323,343 and423,443 to maintain the sub-assembly of the elongatedtubular electrode330,430 inserted into the elongated lumen341,441 of theporous electrode support340,440 affixed to theinsulated electrode sheath320,420. The adhesive does not block migration of conductive fluid around theporous electrode support340,440. Electrode sheathe320,420 is also formed having an elongated tapered internal recess421441 that receives themalleable backbone310,410 as shown inFIGS. 2 and 3. Again, adhesive may be applied to the contacting surfaces of thebackbone310,410 and the elongated tapered internal recess421441.
• Thehandle10 is formed of aright handle half600 depicted inFIGS. 8A-8C and aleft handle half700 depicted inFIGS. 9A-9C.Trigger sections620 and720 of the respective right and lefthandle halves600 and700 include downwardly openingrecesses621 and721 in which trigger20 is mounted (as shown inFIGS. 1 and 10) to pivot inward to apply tension oncable390 or outward to release tension oncable390.Upward openings627 and727 in respective right and lefthandle halves600 and700 receive thethumb slide25. Inwardly extendingprojections630 and730 are also formed in respective right and lefthandle halves600 and700 that function to constrict thefluid conduits370 and470 to prevent conductive fluid flow therethrough when thetrigger20 is released as described further below.
• A set of circular matching, laterally opposed,sockets623 and723 are formed in the interior surfaces of the respective right and lefthandle halves600 and700. The set ofsockets623,723, receive a pair ofpivot bosses206,206′ of trigger20 (shown in Figure.13A) about which thetrigger20 pivots as described further below. A set of matching, laterally opposed, and slightly elongated or oblong,sockets624 and724 are formed in the interior surfaces of the respective right and lefthandle halves600 and700. The set ofsockets624,724 receive and guide a trigger lock27 (shown inFIGS. 11A and 11B) that interacts withtrigger20 as described further below. The oblong shape of the set ofsockets624,724 assists in allowing thetrigger20 to ratchet along thetrigger lock27 when trigger is drawn inward to tension thecable390 during closing of thejaws35,45 as described further below.
• A further set of matching, laterally opposed,elongated sockets625 and725 are also formed in the interior surfaces of the respective right and lefthandle halves600 and700. The set ofsockets625,725 receive and guide a link arm26 (shown inFIGS. 12A and 12B) that interacts withtrigger20 as described further below.
• As shown inFIGS. 8B and 9B, the distal portions of right and lefthandle halves600 and700 are formed with internal cylindrical recesses orsockets612 and712 that receive the laterally extendingbosses552 of collar550 (FIG. 2).Internal grooves611 and711 are also formed within the distal portions of right and lefthandle halves600 and700 in which the c-clip524,flat washer520 and spring washer522 (FIGS. 2 and 3A) are fitted.
• As shown inFIGS. 8C and 9C, the right and lefthandle halves600 and700 are also provided with a series of laterally extending, perpendicularinternal walls628 and728 that include slots and recesses for routing the fluid conduits ortubes370 and470, thecable390 and theinsulated wire conductors360 and460 that extend through the length ofhandle10.
• Thetrigger20,thumb slide25, and the associatedlink arm26 and triggerlock27 are shown assembled to theright handle half600 inFIG. 10 with thetrigger20 in the released position and thethumb slide25 in the unlocked distal or retracted position. Thetrigger lock27 is shown in greater detail inFIGS. 11A-11B, thelink arm26 is shown in greater detail inFIGS. 12A-12B, and thetrigger20 is shown in isolation inFIGS. 13A-13B.
• Trigger20 is provided with laterally extendingcylindrical pivot bosses206,206′ that are mounted intosockets723 and623, respectively. When released, trigger20 extends outward through downwardly openingrecesses621 and721. When pulled, trigger20 is pivoted inwardly into the handle recesses621 and721 aboutpivot bosses206,206′ to apply tension to thecable390 that draws the upper andlower jaws35 and45 together.Cable390 is mounted within alubricious tube391, extending from theproximal wall628 to thedistal end15 of thehandle10, to allow thecable390 to move freely within thehandle10 whentrigger20 is pulled or released.
• Trigger20 is coupled to the proximal end ofcable390 throughlink arm26, illustrated in isolation inFIGS. 12A and 12B.Link arm26 is provided at a distal end with two laterally extendingbosses262 and262′ that are received in circular sockets204 (one of which is shown inFIG. 13B) formed on the interior walls of theinternal chamber202 oftrigger20 to thereby pivotally mount the distal end of thelink arm26 to thetrigger20.Link arm26 is formed with alongitudinally extending slot266, allowing compression of the distal end of thelink arm26 to facilitate positioning ofcylindrical bosses262 and262′ within the correspondingsockets204 within thetrigger20. As also shown inFIG. 13B,longitudinal slots215 are provided in the interior202 to assist insertion of thebosses262,262′ onlink arm26 intosockets204 intrigger20 during assembly.Link arm26 is provided at its proximal end with two laterally extending,circular bosses264 and264′ that are received within theelongated slots625 and725, respectively, in the respective right and lefthandle halves600 and700. Whentrigger20 is released, thecircular bosses264 and264′ are disposed at the distal ends of the opposedelongated slots625 and725, respectively. Whentrigger20 is pulled inward, the proximal end of thelink arm26 is moved proximally within theopposed slots625 and725, applying tension tocable390.
• Cable390 is coupled to thelink arm26 by means of a swagedretainer24, mounted within acoil spring28.Coil spring28 is fitted within a generallycylindrical chamber266 formed extending at 90 degrees to the proximal end oflink arm26.Cable390 passes through an upwardly facingslot270 inlink arm26 and through the interior ofspring28 toretainer24.Spring28 is normally extended withinchamber266 but is compressed to provide protection against over tensioning of thecable390, if the upper andlower jaws35 and45 encounter significant resistance to further movement toward one another. The configuration of thetrigger20,link arm26 andslots625 and725 provide a mechanism whereby, thecable390 is pulled proximally relatively quickly during initial upward movement of thetrigger20 to facilitate initial rapid closing of thejaws35 and45. Thecable390 is pulled relatively more slowly during further upward movement of thetrigger20 to provide increased control to the physician during final compression of thejaws35 and45 against the tissue to be ablated.
• Trigger20 is also provided with adistally extending projection208 terminating with a laterally extending, generally cylindrical,boss210 shown best inFIG. 13B. As illustrated inFIG. 10, when thetrigger20 is released and in its most downward position (corresponding to the point of maximum jaw opening), the fluid conduits ortubes370 and470 are disposed side by side and compressed betweencylindrical boss210 and the inwardly extendingprojections630 and730. This compression of the fluid conduits ortubes370 and470 prevents flow of conductive fluid from the fluid source and out of theelectrodes330 and430 and the electrode mounts340 and440 when the hemostat is not in use.
• Thetrigger20 is also formed with a laterally extendingslot212 having an array ofteeth214 formed along one side of theslot212. A trigger lock mechanism is provided involving the interaction of thethumb slide25 with thetrigger20 through atrigger lock27 that is coupled at one end with thethumb slide25 and selectively engages theteeth214 to retain the upper andlower jaws35 and45 at a fixed position adjacent tissue to be ablated without requiring the physician to continually apply pressure to trigger20. Distal or forward movement of thethumb slide25 causes thetrigger lock27 to engage theteeth214, and proximal or rearward movement of thethumb slide25 releases the engagement. Thetrigger20 can be operated freely by the physician to open or close the upper andlower jaws35 and45 when thethumb slide25 is in the rearward position. With thethumb slide25 in the forward position, thetrigger20 can be moved inward ratcheting over theteeth214 to close the upper andlower jaws35 and45, but thetrigger20 will not move outward upon release by the physician.
• Thetrigger lock27 depicted in isolation inFIGS. 11A and 11B comprises an elongated link arm275 havingrods272 and278 laterally extending parallel to one another from opposed ends of the link arm275. As shown inFIG. 10, therod272 is inserted through theslot202 so that the link arm275 extends alongside thetrigger20 within therecess721. Therod278 extends into a generally centrally locatednotch252 of a resilient beam section250 of thethumb slide25.Cylindrical pivot bosses276 and276′ extend laterally on either side of the link arm275 in alignment withrod272 and are inserted intosockets724 and624, respectively.
• Therod272 inserted through theslot212 extending through thetrigger20 is formed with a laterally extending rampedtooth274 that is selectively engagable with one of the rampedteeth214 formed along the proximal edge ofslot212, when thetrigger lock27 is pivoted forward from the position illustrated inFIG. 10 by distal or forward movement of thethumb slide25 by the physician. Movement of thetrigger20 inwardly into the handle recess with thetrigger lock27 advanced forward from the position illustrated inFIG. 10 causes the interaction of thetooth274 on thetrigger lock27 with theteeth214 to retain thetrigger20 in position when pressure is released. The oblong configuration ofsockets624 and724 that receivebosses276′ and276 of thetrigger lock27 allow thetrigger lock27 to move slightly forward during inward movement of thetrigger20 so that thetooth276 ontrigger lock27 may ratchet along the rampedteeth214 oftrigger20. Interaction of theteeth214 with the rampedtooth274 on thetrigger lock27 prevents outward movement of thetrigger20 as long as thethumb slide25 remains in the forward position in the slot formed byopenings627 and727.
• Release of thetrigger20 is accomplished by proximal or rearward movement ofthumb slide25, pivoting the rampedtooth274 out of engagement with a tooth of theteeth214 alongslot212 which allows the upper andlower jaws35 and45 to open unless the physician holds thetrigger20 in position. Thetrigger20 is urged outwardly out of the recess inhandle10 byspring23 upon release of thetrigger20 and rearward movement of thethumb slide25. When thetrigger20 reaches its full outward position, flow of conductive fluid throughfluid conduits370 and470 is terminated as the tubing is compressed between the laterally extendingboss210 and the inwardly extendingprojections630 and730, as discussed above.
• Thethumb slide25 is provided with a resilient beam section250, having a generally centrally locatednotch252 which engages the laterally extendingrod278 ontrigger lock27, coupling thethumb slide25 to thetrigger lock27. Thethumb slide25 is preferentially retained at either the proximal, rearward or distal, forward point of its travel, without the necessity of the physician manually maintaining pressure on thethumb slide25 due to the resilience of the beam250 and the arcuate path of travel of therod278.
• FIG. 14 illustrates a proximal portion of the assembled hemostat ofFIG. 1 with theleft handle half700 removed to show themulti-conductor cable80 andfluid conduit70 extending through thestrain relief60 and their joinder to thewire conductors360,460 and thefluid conduits370,470.
• The distal end of thefluid conduit80 is coupled through a fitting802 to proximal end offlexible tubing804. The distal end offlexible tubing804 is coupled to the trunk of a Y-connector806, and the distal legs of theY connector806 are coupled to arms of a D-connector810. TheD connector810 is formed of a flexible plastic; e.g., silicone rubber, providing spaced apart fluid channels that are coupled to the proximal ends of thefluid conduits370 and470.
• The fitting804 supports a proximal flow controller orregulator820 that has a precisely sized orifice that limits conductive fluid flow into the Y-connector806. Theflow regulator820 establishes a fixed flow rate and pressure within the Y-connector806 regardless of the pressure of the fluid source that is available in the surgical theatre. The flow rate is established depending upon the upper and lower electrode area and design.
• TheD connector810 supports a pair ofdownstream flow regulators822 and824 that have equal, precisely sized orifices that further reduce the fluid flow rate and pressure of the conductive fluid entering thefluid conduits370 and470. Thedownstream flow regulators822 and824 ensure that an even flow of conductive fluid is provided from within theY connector806 into thefluid conduits370 and470. By this mechanism, the hemostat may be operated without the necessity of an associated pressurized fluid source and still provide controlled and even fluid flow to the upper andlower jaws35 and45 that contact the tissue to be ablated.
• An optional light emitter, e.g., anLED830, is depicted inFIG. 14 located within thestrain relief60 and coupled through anelectrical junction832 with theinsulated wire conductors360 and460. Thewire conductors360 and460 can take the form of a twisted wire cable that extends distally from theelectrical junction832 through the length of the handle to theswivel assembly50 where they are separated as shown inFIGS. 3A and 4. Separate wire conductors within acable834 extend from theelectrical junction832 to theLED830. In use, theLED830 is illuminated in response to activation of an associated RF electrosurgical generator, and the LED illumination illuminates thestrain relief60, which is preferably fabricated of a translucent flexible material, such as silicone rubber or the like. The physician will typically hold thehandle10 in orientations that make thestrain relief60 visible, and illumination of theLED830 indicates to the physician that RF energy is being applied to the electrodes
• The proximal portion of thehandle10 may also optionally carry other electronic components including circuitry containing calibration information, for example calibrating a thermocouple if provided to sense electrode or tissue temperature. Circuitry containing identification information or providing re-use prevention may also be included, however such features are not believed to be essential to or a part of the present invention.
• FIGS. 15A and 15B illustrate an alternative embodiment of the electrode described above that can be employed in modified upper and lower jaw assemblies30A and40A corresponding generally to upper andlower jaw assemblies30 and40. The upper and lower jaw assemblies30A,40A have amalleable backbone310,410 and asheath320,420 as described above that are attached to the respective upper and lower jaw mounts300 and400 as shown inFIGS. 2 and 3. However, electrode330A,430A incorporates an exposedelongated electrode extension350A,450A extending to the outer surface ofporous electrode support340A,440A and along thejaw35,45 that is intended to directly contact the tissue to be ablated. In this embodiment, conductive fluid is delivered as described above into the lumen of the internaltubular electrode330A,430A, which may be substantially the same as thetubular electrodes330,430. Anelongated electrode surface352A,452A of theelectrode extension350A,450A and the contacted tissue are irrigated by conductive fluid emitted through the fluid ports of the internaltubular electrode330A,430A and conducted through the pores of theelectrode support340A,440A.
• Theelectrode extension350A,450A is depicted prior to assembly with theelectrode support340A,440A and the elongatedtubular electrode330A,430A inFIGS. 16A and 16B. As formed, theelectrode extension350A,450A includes an elongatedstraight portion352A,452A that is mounted against the exposed to the exterior of theelectrode support340A,440A. A distally extending portion360A,460A is adapted to be inserted into the lumen of theelectrode support340A,440A to extend alongside the elongatedtubular electrode330A430A as shown inFIG. 15B.
• A series ofbarbed projections354A,454A extend laterally away from the elongatedstraight portion352A,452A. Theelectrode extension350A,450A is adapted to be bent back atjunction356A,456A to enable insertion of the series ofbarbed projections358A,458A into theelectrode support340A,440A. Theproximal end362A,462A is electrically connected to the proximal ends of thetubular electrodes330A,430A and the distal ends of thewire conductors360,460.
• This alternative exposed electrode embodiment can be formed by modifying thetubular electrode330,430 to have a conductive electrode band extending from the tubular electrode along the surface of theelectrode support340,440. Alternatively, this alternative electrode design can be accomplished without use of thetubular electrode330,430, whereby conductive fluid is delivered to a lumen of theelectrode support340,440 or to a fluid channel between theelectrode support340,440 and thesheath320,420, and the exposed electrode band is supported by the electrode support
• The embodiments of the electrosurgical hemostat described above contain a number of valuable features and components, all of which contribute to provide a hemostat, which is convenient to use while providing substantial flexibility in use. However, many of the features of the hemostat could be employed in hemostats of other designs. For example, the trigger mechanism and/or the trigger lock mechanism of the above-described hemostat would certainly be of use in conjunction with cable activated hemostats having jaws of alternative designs to that described above. Similarly, the jaw assembly of the present hemostat might well be employed in conjunction with alternative trigger mechanisms. And/or in conjunction with alternative electrode designs, including electrodes which might not include provision for fluid irrigation and/or in the context of the hemostat having jaws that are rigid and not malleable by the physician to assume desired configurations. Further the specific electrode design employed in the hemostat design described above would be of significant use in conjunction with other hemostat types, including hemostats having jaws which are moved toward one another by alternative mechanisms. Similarly, a strain relief of the type described above including an LED indicator is believed to be of value in conjunction with any number of electrosurgical tools, particularly those in which the strain relief is within the physician's field of view, during normal operation of the hemostat. As such, the above description should be taken as exemplary, rather than limiting, with regard to the claims which follow.

Claims (2)

1. A device for performing a surgical procedure, comprising.

an elongated handle;

a pair of closeable jaws on a distal portion of the handle;

means on at least one of the jaws for ablative treatment of tissue;

means for closing the jaws on tissue; and

means for adjusting roll and pitch of the pair ofjaws relative to the handle.

2.-72. (canceled)

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