Abstract:
Described are a method and biopsy device which includes a tissue cutting arrangement and a cauterizing element. The tissue cutting arrangement is operable to excise a tissue sample from a sampling site. The tissue cutting arrangement defines a sample chamber therewithin for receiving a tissue sample after excision by the tissue cutting arrangement. The sample chamber includes insulated sample contacting surfaces. The cauterizing element is formed on at least a portion of an exterior surface of the tissue cutting arrangement. The cauterizing element is actuatable to cauterize the sampling site after excision of the tissue sample.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the priority to the U.S. Provisional Application Ser. No. 60/843,963, entitled “TISSUE SAMPLE PROTECTING CAUTERIZING BIOPSY FORCEPS,” filed Sep. 12, 2006. The specification of the above-identified application is incorporated herewith by reference. 
     
     BACKGROUND INFORMATION 
       [0002]    Biopsy is the preferred method of diagnosis for many diseases and conditions. When it is desired to biopsy tissue within certain body structures such as, for example, hollow organs or lumens, an endoscope or similar device may be used to reach target issue and to insert cutting and retrieval devices to that tissue via the working lumen of the scope. 
         [0003]    Because of the cutting involved, cauterization elements are often inserted to the sampling site to stop the bleeding that may occur at the sampling site. These cauterization elements may be part of a separate device or may be included in the cutting and/or retrieval devices used to obtain the biopsy. However, it may be difficult with conventional devices to achieve a desired degree of cauterization (i.e., sufficient to stop the bleeding) without excessive damage to surrounding tissue. In addition, exposure to excessive heat may damage the tissue sample reducing or destroying its diagnostic value. 
       SUMMARY OF INVENTION 
       [0004]    The present invention relates to a biopsy device which includes a tissue cutting arrangement and a cauterizing element. The tissue cutting arrangement is operable to excise a tissue sample from a sampling site. The tissue cutting arrangement defines a sample chamber therewithin for receiving a tissue sample after excision by the tissue cutting arrangement. The sample chamber includes insulated sample contacting surfaces. The cauterizing element is formed on at least a portion of an exterior surface of the tissue cutting arrangement. The cauterizing element is actuatable to cauterize the sampling site after excision of the tissue sample. 
         [0005]    The present invention also relates to a method of biopsy. An insulated biopsy forceps is advanced to a sampling site within a body lumen. A tissue sample from the sampling site is actuated from a cutting element of the forceps from outside the body to excise. The tissue sample is retained in a sample chamber within the forceps, the sample chamber having insulated interior surfaces. A cauterizing element is energized to cauterize the sampling site. 
         [0006]    The present invention further relates to a biopsy system with cauterization. The system may include a shaft having a distal end insertable through a scope to a sampling site within a body; a non-conductive shaft coating covering at least a portion of the shaft; a housing disposed at a distal end of the shaft; a cutting element of the housing operable by a user to excise a sample tissue from the sampling site; a sample chamber defined within the housing for retaining the excised sample tissue; a cauterization element of the housing to cauterize the sampling site after excision of the sample tissue; and a non-conductive housing coating covering at least parts of surfaces of the housing. 
     
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]      FIG. 1  is a perspective view showing an embodiment of the biopsy forceps according to the invention in an open configuration; 
           [0008]      FIG. 2  is perspective view of the biopsy forceps shown in  FIG. 1  in the closed configuration; 
           [0009]      FIG. 3  is a view of the biopsy forceps shown in  FIG. 1  attached to a carrier device; 
           [0010]      FIG. 4  is a perspective view of a biopsy forceps according to a second embodiment of the present invention, in a closed configuration; 
           [0011]      FIG. 5  is a perspective view of the biopsy forceps shown in  FIG. 4 , in an open configuration; 
           [0012]      FIG. 6  is a perspective view of a biopsy forceps according to a third embodiment of the present invention, with a separate cauterization element; 
           [0013]      FIG. 7  is a perspective view of a biopsy forceps according to a different embodiment of the present invention, with a laser cauterization element; and 
           [0014]      FIG. 8  is a perspective view of a biopsy forceps according another embodiment of the present invention, comprising a sample basket. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to devices for performing a biopsy. More specifically, the invention relates to devices used to retrieve biopsy tissue samples and to cauterize the resulting wound. 
         [0016]    As shown in  FIG. 1 , a biopsy forceps  100  according to the present invention adapted to obtain a sample of tissue and immediately cauterize the sample site while preserving the tissue sampled therefrom comprises a shaft  104  used to advance through, for example, an endoscope the distal head  102  to the target sample area. The distal head  102  comprises the cutting instruments used to remove the sample tissue from its surroundings. 
         [0017]    The forceps  100  according to the exemplary embodiment of the present invention comprises a pair of hinged jaws  106 ,  108  including overlapping teeth  112 , or other similar cutting surfaces. The opposing cutting surfaces of the jaws  106 ,  108  may be brought together over the sample tissue once the distal head  102  has been advanced to the sampling site within, for example, a body lumen or cavity. The exemplary jaws  106 ,  108  pivot about a hinge  110 , so that they can open and close using a remote actuator  104 , that may be operated by a user from outside the patient&#39;s body. 
         [0018]    The jaws  106 ,  108  are preferably shaped to form a sample holder, such as a sample cup  114  that becomes an enclosed sample chamber  116  once the jaws  106 ,  108  are closed. The sample chamber  116  retains the sample for removal from the body while protecting the sample from contamination during removal. The jaws  106 ,  108  are preferably designed to automatically enclose the sample within the chamber  116  after the sample has been excised to prevent loss of the sample during retrieval. Those of skill in the art will understand that different shapes and locations of the sample chamber  116  may be used, without departing the scope of the present invention. 
         [0019]    Multiple surfaces of the biopsy forceps  100  are coated with an insulating material to prevent the non target tissue and the sample tissue from being damaged. For example, the insulation may comprise PTFE or PFA materials, ceramics or any other coating that reduces heat transfer and is electrically non-conductive. The insulating coating may be sprayed, dipped or painted on the device. As shown in the drawings, the device according to this embodiment comprises coated, non-conductive surfaces  120  formed as described above as well as non-coated, conductive surfaces  122  which deliver energy to cauterize the sampling site. A large portion of the exemplary device is coated with the non-conductive insulation, including the shaft  104  and the sample cup  114 . As would be understood by those skilled in the art, for forceps according to alternate embodiments using other forms of energy (e.g., laser) to cauterize tissue, the insulation need not be electrically non-conductive and may be simply thermally insulative. For example, an electrically conductive, thermally insulative material such as conductive acetal polymer black carbon filled Pomaflux CN-F may be used to the shaft  104  and/or the sample cup  114 . A laser may be used to heat the jaws  106 ,  108  for cauterizing tissue when need to be thermally insulated but not electrically insulated. 
         [0020]    When the jaws  106 ,  108  are closed, the conductive portions  122  form a generally bullet shaped cauterization tool that may be used to stop bleeding within the sampling site. The user may, for example, visualize the site via an endoscope to direct the distal head  102  to the site of bleeding to cauterize and seal the wound. Because of the insulation disposed on the surfaces  120 , the portion of tissue cauterized may be accurately targeted minimizing inadvertent cauterization of the surrounding tissue. The sample within the sample chamber  116  is also protected from damage during the cauterization steps by insulation coated on the inside portions of the jaws  106 ,  108 . 
         [0021]    A second embodiment of a biopsy forceps according to the present invention is shown in  FIGS. 4 and 5 . In this embodiment the conductive region of the device is smaller and shaped to more closely direct RF energy path in a selected direction. As shown, the forceps  202  comprises a pair of jaws  206 ,  208  having a cutting portion  212  for removing tissue samples. A cup  214  is preferably formed by the jaws  206 ,  208  to hold the tissue sample during retrieval and large portions of the jaws  206 ,  208  are coated with a non-conductive material to form non-conductive surfaces  220  that extend over the internal portions of the jaws  206 ,  208  to protect the sample tissue. 
         [0022]    In this embodiment, the conductive surfaces  222  of the device are limited to the distal tip of the jaws  206 ,  208 . For example, the outer distal ends of the forceps  202  are left uncoated to form a substantially circular cauterization zone. According to this embodiment, the shape of the conductive surfaces  222  directs RF energy toward a grounding pad and away from the sample of tissue contained within the sample chamber  216 . In other exemplary embodiments, the conductive surfaces  222  may be located on external surfaces of sidewalls of the jaws  206 ,  208 , e.g., about 180° apart. For example, the conductive surfaces  222  may be located on opposite sides of the jaws  206 ,  208  adjacent the contacting edges and/or on upper external portion of the jaw  206  and a lower external portion of the jaw  208  when the contacting edges are in a horizontal plane. In this manner, the forceps  202  need only be rotated, at most, about 90° to align one of the conductive surfaces  222  with the target tissue region to be cauterized. In another exemplary embodiment, the conducting surfaces  222  may be selectively activated, e.g., one on/one off. Preferably, the conductive surfaces  222  are semi-circular, forming a substantially circular shape when the jaws  206 ,  208  are closed. 
         [0023]    The preceding embodiments of the biopsy forceps may be based on existing forceps used for sample tissue retrieval. For example, the Barracuda and the Tiger Shark lines of biopsy forceps, and the Stone Retrieval Devices Basket line manufactured by the Boston Scientific Corporation of Natick, Mass., may be modified to operate in accord with the teachings of the present invention by applying non-conductive coatings in to selected areas as described above. 
         [0024]    In alternate embodiments of the present invention, the jaws or cutting elements of the device are not used to perform the cauterization of the sampling area. Instead, a separate media is used to cauterize the wound, for example by directing RF or other energy to the target tissue. According to these embodiments, a path of least resistance is provided toward the tissue to be cauterized (e.g., toward a grounding pad located on an opposite side of the tissue to be cauterized) and away from the sample tissue held within the device. The cauterization media may be a fixed or a movable protrusion that extends from the biopsy forceps towards the target tissue. 
         [0025]    As shown in  FIG. 6 , forceps  300  according to an exemplary embodiment of the invention comprises a pair of jaws  302 ,  304  at the distal end of a shaft  312  of the forceps  300  forming a sample chamber  314  when pivoted about the hinge  310  to the closed configuration. The forceps  300  may further include a tissue grabber  306  which telescopes distally from a lumen  308  of the shaft  312  to hold tissue in place. The forceps  300  further includes an optic fiber  326  (shown in  FIG. 7 ) which, during insertion of the device and excision of the tissue, is preferably stored within the shaft  312  and, after the sample has been placed within the sample chamber  314 , extended to the site from which the tissue was removed to cauterize the resulting wound. Alternatively, the optic fiber  326  may be fixed in an extended position and activated only after the tissue sample has been enclosed within the sample chamber  314 . 
         [0026]    A biopsy forceps  320  as shown in  FIG. 7 , comprises a pair of pivoting jaws  322 ,  324  that include cutting elements to remove the sample tissue from the sampling site. As described above in regard to the previous embodiments, the jaws  322 ,  324  close to form a sample chamber  330  in which the tissue sample is stored for removal from the body. The laser light is transmitted to the distal end of the forceps  320  via the optic fiber  326  to a selected position for irradiating tissue in a desired spatial relation to the distal end of the forceps  320 . As would be understood by those skilled in the art, heat transferred to the sample within the sample chamber  330  as the laser energy passes by via the optic fiber is minimal and only a small amount of heat is transferred to non-targeted surrounding tissue on which the laser is not aimed. 
         [0027]    Furthermore as would be understood by those skilled in the art, other mechanisms and/or forms of energy may be used to cauterize the tissue. For example, a resistance type heater may be utilized instead of the laser and RF energy systems described above. Alternatively, a dual lumen may be provided in the shaft of the biopsy forceps according to the invention through which a wire loop (e.g., of nickel-chrome wire) for RF or other forms of electric energy may be advanced to the sampling site to cauterize the tissue. As would be understood, such devices may be powered by an external battery, RF generator or other power source and, as in the embodiments described above, the loops may be fixed or may be telescoping from the shaft of the device. 
         [0028]    As shown in  FIG. 8 , a biopsy forceps  400  according to a further embodiment of the invention includes a basket  410  which captures the tissue sample after it has been excised. The basket  410  of the forceps  400  comprises a channel  408  opening at the distal end  406  and accommodating a heating element such as an RF wire, a fiber-optic cable for delivering laser energy, a nickel-chrome wire or other device which, when passed through the channel  408  to a location adjacent to the target site, may be energized to cauterize the tissue surrounding the site from which the tissue sample was removed. As described above, for electric and RF cauterizing systems, outer surfaces of the channel  408  are preferably made non-conductive, and may be used as an insulator. Teflon PTFE, Teflon PFA, ceramic or other heat resistant materials may be used to form the coating. Of course, such coatings need not be electrically non-conductive for laser based systems. 
         [0029]    In another embodiment, the basket  410  is formed of a plurality of filaments  404  with one or more of the filaments  404  transmitting energy to the target tissue. For example, the one or more filaments  404  may be formed of an electrically conductive wire or fiber-optic cable to transmit RF, laser or other energy to a cauterization element disposed at the distal tip  406 . For example, where one of the filaments  404  is used as a hot element for cauterization, the location of this filament  404  with respect to the interior of the basket  410  is selected to minimize the affect of the heat on a tissue sample retained within the basket  410 . In addition, selected portions of the filament  404  may be insulated (thermally and/or electrically) to maximize energy transfer to the target tissue while minimizing energy transfer to sample tissue retained within the basket  410 . 
         [0030]    The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.