| Electrosurgical hemostat -> Monitor Keywords |
|
|
 
Electrosurgical hemostatRelated Patent Categories: Surgery, Instruments, Electrical Application, ApplicatorsElectrosurgical hemostat description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060195083, Electrosurgical hemostat. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED U.S. APPLICATION DATA [0001] 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 [0002] The present invention relates to surgical tools and procedures generally and relates more particularly to the use of electrosurgical ablation to treat atrial fibrillation. [0003] 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. [0004] 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 [0005] 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. [0006] 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. [0007] 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. [0008] 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. [0009] 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. [0010] 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. [0011] 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. [0012] 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. [0013] 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. [0014] 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. [0015] 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 [0016] FIG. 1 is a plan view of an assembled hemostat according to one embodiment of the present invention. [0017] FIG. 2 is an exploded view of the jaw assembly of the hemostat of FIG. 1. [0018] FIG. 3A is a cross-section view through the jaw assembly of the hemostat of FIG. 1. [0019] FIG. 3B is a cross-section view through lines 3B-3B of FIG. 3A. [0020] 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 of FIG. 1. Continue reading about Electrosurgical hemostat... Full patent description for Electrosurgical hemostat Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Electrosurgical hemostat patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Electrosurgical hemostat or other areas of interest. ### Previous Patent Application: Dual mode lesion formation apparatus, systems and methods Next Patent Application: Method and apparatus for tissue ablation Industry Class: Surgery ### FreshPatents.com Support Thank you for viewing the Electrosurgical hemostat patent info. IP-related news and info Results in 0.1423 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
