Patent Publication Number: US-2004044341-A1

Title: Electrosurgical device and method of use

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] This invention relates to electrosurgical devices and techniques for applying energy to tissue for hemostasis, coagulation or tissue-shrinkage purposes. More particularly, the system provides an electrosurgical “tape” or “patch” that consists of a thin surface-conforming member that can be applied to the surface of a targeted body structure. The system provides mono-polar or bi-polar electrode means within an engagement surface for active Rf energy delivery from the conforming member that conforms and adheres to an organ&#39;s surface (e.g., a liver or lung).  
       [0003] 2. Description of the Background Art  
       [0004] Various devices and techniques have been developed for coagulation or sealing broad surface areas of tissues or organs. For example, argon coagulators are known wherein an ionized gas serves as a gas electrode that is sprayed over a targeted site. Such argon coagulation relies on a first polarity electrode at the instrument working end delivers energy across the gas electrode in cooperates with a ground pad serving as a return electrode. In argon coagulation, the depth of ohmic heating in the tissue surface is not controllable since surface desiccation causes localized high impedances. What is needed is an improved means to cause ohmic heating in tissue to a controlled depth with a conductive electrode that conforms to the targeted tissue surface.  
       SUMMARY OF THE INVENTION  
       [0005] This invention relates to electrosurgical systems and techniques for applying ohmic heating to tissue. More particularly, the invention provides a tape or patch member for conforming to, and adhering to, the surface of a body structure. The tape or patch member then can coupled to a electrical energy source for applying Rf energy to a conductive engagement portion of the tape or patch, which in turn will controllably cause ohmic heating in the engaged tissue surface to shrink, coagulate, ablate or create lesions therein.  
       [0006] The method of the invention is useful for applying energy to surface areas of an organ or other anatomic structure. At the same time, the tape, patch or pad can provide a sealing film over the treated region. Also, the conforming member can carry a pharmacologically active agent for delivery to the treatment site. Further, the tape or patch can be fabricated, at least in part, of a heat-shrink polymer that can contract a selected dimension of the engaged tissue surface.  
       [0007] The use of the thermal shrinkage aspect of the tape or patch can be useful for both thermally shrinking tissue and mechanically contracting the engaged tissue is altering the elastic and dimensional parameters of a patient&#39;s pelvic floor. The use of thermal shrinkage of the tape or patch also can be useful in a lung volume reduction surgery wherein the conforming material is folded or wrapped around a targeted lung segment—and the conforming device of the invention collapses, compresses and seals the substantially surrounded lung segment to thereby reduce to overall lung dimension to allow other non-treated portions of the lung to function better.  
       [0008] The invention advantageously provides a tissue surface conforming member with a bi-polar electrode system that can be used to deliver bi-polar Rf energy to tissue.  
       [0009] The invention provides a system and method for creating a bi-polar electrode that perfectly conforms to irregular tissue surfaces.  
       [0010] The invention provides a method for controllably delivering Rf energy to a selected depth in tissue by (i) controlling the center-to-center distance between spaced apart tissue-surface conforming electrodes, and for (ii) controlling the rate of energy delivery between the spaced apart electrodes.  
       [0011] The invention provides devices and methods for controllably shrinking and collapsing an engaged tissue volume such as a lung.  
       [0012] The invention provides devices and methods for controllably coagulating and sealing an organ surface such a patient&#39;s liver.  
       [0013] The invention provides devices and methods for creating controlled depth lesions in tissue, such as in pulmonary vessels to alter conduction pathways. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014] Other objects and advantages of the present invention will be understood by reference to the following detailed description of the invention when considered in combination with the accompanying Figures, in which like reference numerals are used to identify like components throughout the disclosure.  
     [0015]FIG. 1 shows a plan view of an exemplary hand-held instrument with a working end that dispenses a Type “A” conforming electrosurgical device or tape member corresponding to the invention.  
     [0016]FIG. 2 is an enlarged cut-away view of the conforming electrosurgical member of the invention.  
     [0017]FIG. 3 depicts multiple layers of the conforming electrosurgical tape member over a targeted site.  
     [0018]FIG. 4 is a bi-polar embodiment of the conforming electrosurgical tape member of FIG. 2.  
     [0019]FIG. 5 illustrates an alternative Type “B” embodiment of the conforming electrosurgical patch member and its method of use.  
     [0020]FIG. 6 illustrates a bi-polar embodiment of the conforming electrosurgical member of FIG. 5 and its method of use. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0021] 1. Type “A” embodiment of surface-conforming electrosurgical device tape. FIGS. 1 and 2 illustrate a Type “A” electrosurgical device or tape  100  corresponding to the invention for creating ohmic heating in a tissue surface, after adhering to the surface. The handle portion  108  and introducer member  112  in FIG. 1 are an optional component of the system for dispensing tape  100  as shown in FIG. 2, for example in an endoscopic surgery. In an open surgery, the tape or patch can be applied manually—and is cuttable and trimmable with a scissors.  
     [0022] Of particular interest, the tape member  100  is adapted to completely conform to, and adhere to, the surface of a targeted body structure T in FIG. 2, which for example can be the surface of a liver. The tape  100  can be used to controllably cause ohmic heating of a tissue surface to coagulate, ablate, shrink or create lesions in the targeted surface. At the same time, the polymer tape member can have provide a sealing member with a controlled porosity, or no porosity, in the device. A microporous tape member also can carry any desired pharmacological agent for delivery to the tissue. The layers of the device  100  also can be substantially of a biodegradable polymer.  
     [0023] As can be seen in FIG. 2, the tape  100  has a first surface portion  120  that comprise a flexible conductive material that defines an engagement surface  122  for engaging tissue. The tape  100  has second surface  125  that comprises a flexible insulative material. In one embodiment as shown in FIG. 2, the flexible conductive material comprises conductive filaments  128  in a conductively doped polymer  130 . The tape  100 , and more specifically, the conductive filaments  128  are coupled to electrical source  140 . Conductively doped plastics are known in the art, and for example can be doped with carbon particles.  
     [0024] In another embodiment depicted in FIG. 4, the tape  100  has a first surface portion  120  that carries a plurality of spaced-apart flexible conductive portions indicated at  142  and  144 . Each such portion can be a conductive polymer, and each may have its own conductive filaments therein that are coupleable to an electrical source. These conductive portions  142  and  144  can operate as spaced-apart bi-polar electrodes to control depth of ohmic heating—which is largely a function of center-to-center spacing of the electrodes. A multiplexer can be provided to apply Rf energy between selected various spaced-apart electrode groups to further control depth of ohmic heating.  
     [0025] In a preferred embodiment, the tape  100  has a second insulative surface  125  of a transparent polymer. The tape  100 , and each of its layers, can be of any suitable flexible polymer, such as a polysiloxane, polyurethane, PFTE, polyacrylate, polyamide, polyester, polyolefin, nylon or any co-polymers thereof. In one preferred embodiment, the tape  100  is stretchable. In another preferred embodiment, the tape  100  is elastic. In a typical embodiment, the tape  100  is foldable and deformable to adhere to irregular tissue surfaces. In another preferred embodiment, either or both the first and second surfaces of the tape member  100  carry a thermochromic composition to provide a visual indicator of temperature of the tape and the engaged tissue.  
     [0026] The tape  100  can carry any suitable adhesive composition on its engagement surface  122 . The adhesive can be a cyanoacrylate glue, or a fibrin-carrying glue.  
     [0027] In FIG. 3, it can be seen that many multiple layers of the tape  100  can be applied over each other to engage broad tissue surfaces. This is a particular advantage of providing the insulative layer  125  over the conductive layer  120 , particularly in the bi-polar tape version of FIG. 4.  
     [0028]FIG. 1 shows a handle member that serves as a dispenser of tape  100 . It can be understood how the lever  146  can operate an internal ratchet to rotate a tape spool of FIG. 2 to dispense tape. The lever  146  can serve as a dual-acting actuator wherein a full squeeze of the lever cuts the tape after Rf energy delivery with a blade or wire element. The trigger  148  can be used to turn on the Rf delivery from the electrical source.  
     [0029] 2. Type “B” embodiment of surface-conforming electrosurgical tape or pad. FIGS. 5 and 6 illustrate a Type “B” electrosurgical device in the form of patch-like surface-conforming member  200  for creating ohmic heating in a tissue surface. In this embodiment, the conforming member  200  is not directly coupled to the electrical source  140  by electrical leads as is contemplated by the Type “A” device. The conforming member  200  rather is applied and adhered to the tissue surface as an independent component. Thereafter, the distal end of an introducer with an exposed electrode contact (or contacts) is placed in substantial contact with electrode portion  215  in the otherwise insulated outer layer  225  of the patch  200  to deliver Rf energy thereto. FIG. 5 shows a first engagement layer  225  that is of a conductive flexible polymer as described previously. FIG. 6 shows a bi-polar variant of the invention. It can be seen how an introducer with bi-polar electrodes can interface with contacts  235   a  and  235   b  to apply energy to the conforming member  200 .  
     [0030]FIG. 6 shows another aspect of the invention wherein the conforming member  200 , that is, either or both the first and second surfaces  220  and  225  are at least in part a heat-shrink polymer. Thus, after the conforming member  200  is glued to the tissue surface—such as a pelvic floor—the material can be reduced in a selected dimension (see arrows in FIG. 6) by heat from the first and second surfaces  220  and  225  which effectively can be resistively heated. At the same time, the tissue can be heated for the purpose of shrinkage.  
     [0031] In another similar embodiment, it can be easily understood how a patch or tape having a heat-shrink capacity can be folded and adhered around a lung segment. Thereafter, the entire patch can be shrunken by heat to compress the engaged lung volume that is substantially surrounded by the tape. At the same time, the patch will seal an exterior of the lung. The compressed lung segment then will allow other lung tissue to function better—in a type of lung volume reduction surgery. The sealed, encapsulated and shrunken lung volume also can be resected to further enhance lung volume reduction.  
     [0032] In another embodiment, it can be understood how a patch or tape (without heat-shrink capacity) can be extended around at least a portion of a patient&#39;s vasculature to create thermal effects and lesions therein. For example, a tape device could extended about a patient&#39;s pulmonary vessels to alter conduction pathways in an endoscopic surgery, as in known in treatments for atrial fibrillation and similar disorders of electrical conduction pathways in and about the heart.  
     [0033] Those skilled in the art will appreciate that the exemplary embodiments and descriptions of the invention herein are merely illustrative of the invention as a whole. Specific features of the invention may be shown in some figures and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention. While the principles of the invention have been made clear in the exemplary embodiments, it will be obvious to those skilled in the art that modifications of the structure, arrangement, proportions, elements, and materials may be utilized in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from the principles of the invention. The appended claims are intended to cover and embrace any and all such modifications, with the limits only being the true purview, spirit and scope of the invention.