US 20060195083 A1
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.
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.
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.
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.
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.
In reference to
The jaw assembly 90 includes the upper jaw assembly 30, the lower jaw assembly 40, and a swivel assembly 50, discussed in more detail below. The upper jaw and lower jaw assemblies 30 and 40 have opposed upper and lower jaws 35 and 45, respectively, each comprising a fluid assisted elongated electrode assembly. The upper and lower jaw assemblies 30 and 40 support elongated electrodes, discussed in more detail below, each coupled to one of the insulated conductors within conduit 70 extending proximately through the strain relief 60 to electrical connector 85. Each of the jaws 35 and 40 of respective upper and lower jaw assemblies 30 and 40 are also coupled to fluid conduit 80 enabling delivery of saline or other conductive fluid from a source coupled to fitting 75 along the lengths of the opposedjaws 35 and 45.
The swivel assembly 50, provides the physician with the opportunity to position the jaw assembly 90 in a variety of orientations relative to the handle 10, to facilitate placing the 35 and 45 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 the swivel assembly 50 and the jaw assembly 90 to provide a roll adjustment R, preferably through an arc of at least 300 degrees, relative to the axis of the distal end 15 of the handle 10 through interaction of components of the handle and swivel assembly described further below. In addition, the physician can grasp the jaw assembly 90 and adjust it in pitch P relative to the swivel assembly 50 through the interaction of components of the jaw assembly 90 and the swivel assembly 50 described further below. Preferably, the available arc of pitch P adjustment extends over at least 90 degrees. Moreover, the upper and lower jaws 35 and 45 are malleable as described further below. The combination of these features and the S-shape handle 10 make the hemostat highly versatile in use.
The trigger 20 is employed to open (separate apart) and close (draw together) the jaws 35 and 45 and to compress tissue between the jaws 35 and 45 prior to application of RF energy to create an elongated lesion. A thumb slide 25 is provided in conjunction with an internal trigger lock, allowing the position of the trigger 20 and the jaws 35, 45 to be locked. After the trigger 20 is drawn toward the handle 10 to close the jaws 35 and 45, the thumb slide 25 is moved distally relative to the handle 10 to cause an internal trigger lock to engage one of a series of ratcheting lock points that define a set of locking locations for the jaws 35, 45, as described further below. Movement of the thumb slide 25 proximally relative to the handle 10 releases the trigger 20 and the jaw assembly 90, allowing the jaws 35, 45 to return to a fully open position. The interaction of the trigger20, thumb slide 25 and the associated trigger lock mechanism frees the physician from the need to maintain pressure on the trigger 20 to compress tissue between the jaws 35, 45 during the ablation, simplifying operation of the hemostat.
The lower jaw assembly 40 also includes a relatively rigid, lower jaw mount 400, an elongated backbone 410, an elongated insulated electrode sheath 420, an elongated conductive electrode 430, and an elongated electrode support 440 that are all formed of the same materials as the corresponding elements of the upper jaw assembly 30. The assembly of the elongated backbone 410, elongated insulated electrode sheath 420, elongated conductive electrode 430, and elongated electrode support 440 is also shown in
The jaw 45 can therefore also be bent laterally with respect to the lower jaw mount 400 to form a curve along the length thereof. In use, the physician manually forms a lateral curve in both the upper and lower jaws 35 and 45 to fit the contour of the tissue, e.g., the heart wall.
The lower jaw mount 400 is formed with a pair of spaced apart, parallel, plates or flanges 401 and 403 each bearing a series of notches 402 and 404, respectively, along the edges thereof. When assembled, a proximal portion of the upper jaw mount 300 is fitted between the flanges 401 and 403. A pin 480 extends through aligned holes through the proximal portion of upper jaw mount 300 and the flanges 401 and 403. The ends of pin 480 are fixed to the flanges 401 and 403 allowing the proximal portion of the upper jaw mount 300 to be rotated about the pin 480, thereby allowing jaws 35 and 45 to open and close. The upper and lower jaws 35 and 45 are separated apart a predetermined distance in the fully closed positions although the electrically insulated distal ends of the insulated electrode sheaths 320 and 420 may contact one another. A spring 450 urges the upper and lower jaws 35 and 45 apart from one another, facilitating opening of the jaws 35 and 45 upon release of the trigger 20 after application of RF energy.
As shown in
As noted above, the swivel assembly 50 and the upper and lower jaw assemblies 30 and 40 can be rotated around the axis of the distal end 15 of the handle 10 to a desired roll adjustment R to facilitate positioning the jaws 35 and 45 for creation of elongated lesions. The proximal portion 506 of swivel 500 is rotatably mounted within a collar 550 that is mounted fixedly to the distal end 15 of the handle 10 as shown in
A cable 390 is also shown in
The elongated tubular electrodes 330 and 430 are illustrated in
The porous electrode support 340, 440, depicted in
The sub-assembly so formed is fitted into the shaped terminus 327, 427 and the elongated channel 323, 423 of the insulated electrode sheath 320, 420 as also shown in
The handle 10 is formed of a right handle half 600 depicted in
A set of circular matching, laterally opposed, sockets 623 and 723 are formed in the interior surfaces of the respective right and left handle halves 600 and 700. The set of sockets 623, 723, receive a pair of pivot bosses 206, 206′ of trigger 20 (shown in Figure. 13A) about which the trigger 20 pivots as described further below. A set of matching, laterally opposed, and slightly elongated or oblong, sockets 624 and 724 are formed in the interior surfaces of the respective right and left handle halves 600 and 700. The set of sockets 624, 724 receive and guide a trigger lock 27 (shown in
A further set of matching, laterally opposed, elongated sockets 625 and 725 are also formed in the interior surfaces of the respective right and left handle halves 600 and 700. The set of sockets 625, 725 receive and guide a link arm 26 (shown in
As shown in
As shown in
The trigger 20, thumb slide 25, and the associated link arm 26 and trigger lock 27 are shown assembled to the right handle half 600 in
Trigger 20 is provided with laterally extending cylindrical pivot bosses 206, 206′ that are mounted into sockets 723 and 623, respectively. When released, trigger 20 extends outward through downwardly opening recesses 621 and 721. When pulled, trigger 20 is pivoted inwardly into the handle recesses 621 and 721 about pivot bosses 206, 206′ to apply tension to the cable 390 that draws the upper and lower jaws 35 and 45 together. Cable 390 is mounted within a lubricious tube 391, extending from the proximal wall 628 to the distal end 15 of the handle 10, to allow the cable 390 to move freely within the handle 10 when trigger 20 is pulled or released.
Trigger 20 is coupled to the proximal end of cable 390 through link arm 26, illustrated in isolation in
Cable 390 is coupled to the link arm 26 by means of a swaged retainer 24, mounted within a coil spring 28. Coil spring 28 is fitted within a generally cylindrical chamber 266 formed extending at 90 degrees to the proximal end of link arm 26. Cable 390 passes through an upwardly facing slot 270 in link arm 26 and through the interior of spring 28 to retainer 24. Spring 28 is normally extended within chamber 266 but is compressed to provide protection against over tensioning of the cable 390, if the upper and lower jaws 35 and 45 encounter significant resistance to further movement toward one another. The configuration of the trigger 20, link arm 26 and slots 625 and 725 provide a mechanism whereby, the cable 390 is pulled proximally relatively quickly during initial upward movement of the trigger 20 to facilitate initial rapid closing of the jaws 35 and 45. The cable 390 is pulled relatively more slowly during further upward movement of the trigger 20 to provide increased control to the physician during final compression of the jaws 35 and 45 against the tissue to be ablated.
Trigger 20 is also provided with a distally extending projection 208 terminating with a laterally extending, generally cylindrical, boss 210 shown best in
The trigger 20 is also formed with a laterally extending slot 212 having an array of teeth 214 formed along one side of the slot 212. A trigger lock mechanism is provided involving the interaction of the thumb slide 25 with the trigger 20 through a trigger lock 27 that is coupled at one end with the thumb slide 25 and selectively engages the teeth 214 to retain the upper and lower jaws 35 and 45 at a fixed position adjacent tissue to be ablated without requiring the physician to continually apply pressure to trigger 20. Distal or forward movement of the thumb slide 25 causes the trigger lock 27 to engage the teeth 214, and proximal or rearward movement of the thumb slide 25 releases the engagement. The trigger 20 can be operated freely by the physician to open or close the upper and lower jaws 35 and 45 when the thumb slide 25 is in the rearward position. With the thumb slide 25 in the forward position, the trigger 20 can be moved inward ratcheting over the teeth 214 to close the upper and lower jaws 35 and 45, but the trigger 20 will not move outward upon release by the physician.
The trigger lock 27 depicted in isolation in
The rod 272 inserted through the slot 212 extending through the trigger 20 is formed with a laterally extending ramped tooth 274 that is selectively engagable with one of the ramped teeth 214 formed along the proximal edge of slot 212, when the trigger lock 27 is pivoted forward from the position illustrated in
Release of the trigger 20 is accomplished by proximal or rearward movement of thumb slide 25, pivoting the ramped tooth 274 out of engagement with a tooth of the teeth 214 along slot 212 which allows the upper and lower jaws 35 and 45 to open unless the physician holds the trigger 20 in position. The trigger 20 is urged outwardly out of the recess in handle 10 by spring 23 upon release of the trigger 20 and rearward movement of the thumb slide 25. When the trigger 20 reaches its full outward position, flow of conductive fluid through fluid conduits 370 and 470 is terminated as the tubing is compressed between the laterally extending boss 210 and the inwardly extending projections 630 and 730, as discussed above.
The thumb slide 25 is provided with a resilient beam section 250, having a generally centrally located notch 252 which engages the laterally extending rod 278 on trigger lock 27, coupling the thumb slide 25 to the trigger lock 27. The thumb slide 25 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 the thumb slide 25 due to the resilience of the beam 250 and the arcuate path of travel of the rod 278.
The distal end of the fluid conduit 80 is coupled through a fitting 802 to proximal end of flexible tubing 804. The distal end of flexible tubing 804 is coupled to the trunk of a Y-connector 806, and the distal legs of the Y connector 806 are coupled to arms of a D-connector 810. The D connector 810 is formed of a flexible plastic; e.g., silicone rubber, providing spaced apart fluid channels that are coupled to the proximal ends of the fluid conduits 370 and 470.
The fitting 804 supports a proximal flow controller or regulator 820 that has a precisely sized orifice that limits conductive fluid flow into the Y-connector 806. The flow regulator 820 establishes a fixed flow rate and pressure within the Y-connector 806 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.
The D connector 810 supports a pair of downstream flow regulators 822 and 824 that have equal, precisely sized orifices that further reduce the fluid flow rate and pressure of the conductive fluid entering the fluid conduits 370 and 470. The downstream flow regulators 822 and 824 ensure that an even flow of conductive fluid is provided from within the Y connector 806 into the fluid conduits 370 and 470. 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 and lower jaws 35 and 45 that contact the tissue to be ablated.
An optional light emitter, e.g., an LED 830, is depicted in
The proximal portion of the handle 10 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.
The electrode extension 350A, 450A is depicted prior to assembly with the electrode support 340A, 440A and the elongated tubular electrode 330A, 430A in
A series of barbed projections 354A, 454A extend laterally away from the elongated straight portion 352A, 452A. The electrode extension 350A, 450A is adapted to be bent back at junction 356A, 456A to enable insertion of the series of barbed projections 358A, 458A into the electrode support 340A, 440A. The proximal end 362A, 462A is electrically connected to the proximal ends of the tubular electrodes 330A, 430A and the distal ends of the wire conductors 360, 460.
This alternative exposed electrode embodiment can be formed by modifying the tubular electrode 330, 430 to have a conductive electrode band extending from the tubular electrode along the surface of the electrode support 340, 440. Alternatively, this alternative electrode design can be accomplished without use of the tubular electrode 330, 430, whereby conductive fluid is delivered to a lumen of the electrode support 340, 440 or to a fluid channel between the electrode support 340, 440 and the sheath 320, 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.