Abstract:
A tumor ablation device may be combined with a diagnostic tool and/or a surgical instrument for offering cancer treatment therapy.

Description:
FIELD OF THE INVENTION 
       [0001]    In various embodiments, the present invention relates generally to medical devices having the ability to treat cancerous tissues using radio-frequency ablation coils. 
       BACKGROUND 
       [0002]    Diagnostic tools, such as endoscopes, are instruments used to examine the interior of a hollow organ or a cavity of the body in order to minimize invasive surgeries. For example, a gastrointestinal (GI) endoscope and a cystoscope can be used to visualize a patient&#39;s GI tract and urinary tract to diagnose, respectively, an unexplained diarrhea or hematuria. Endoscopes are generally used to assist in examination of interior body regions; actually treating a disease may requireseparate procedure. 
         [0003]    Conventionally, endoscopes may be combined with a variety of surgical instruments to enable surgeons to perform various procedures. For example, a combination of a GI endoscope with an endoscopic retrograde cholangiopancreatography (ERCP) device (e.g., a catheter or an endoscopic ultrasound (EUS) fine needle aspiration (FNA) needle) may be used to treat problems associated with bile and pancreatic ducts. The surgeons may perform procedures, such as opening blocked ducts, draining a tumor cyst, or inserting stents, while imaging the region of interest using video, ultrasound, lasers, optics or other imaging modalities. Typically, treating a benign or malignant tumor cyst requires a separate procedure. As a result, patients must often make repeated clinic visits with attendant inconvenience and delays and, potentially, complications associated with progressing symptoms. 
         [0004]    EUS guided FNA (EUS-FNA) has recently been used to drain cystic lesions and collect biopsy samples from them, particulary in the pancreas and the lung, but also in the esophagus and elsewhere. However, current methods for ablating cysts after draining and/or biopsy by EUS-FNA utilize fluid ablative agents such as alcohol or mechanical tools for resection or curettage. These are imprecise and may undesirably spare potentially malignant cystic tissue and/or ablate healthy tissue near the lesion, and a significant need exists in the field for systems and methods which permit more precise tissue ablation in connection with EUS-FNA. 
       SUMMARY 
       [0005]    In various embodiments, the present invention combines endoscopic imaging and/or surgical instruments, such as endoscopic retrograde cholangiopancreatography (ERCP) devices, with systems and methods for delivering energy to tissue; this allows physicians to image the target region and deliver radiofrequency energy for heating and/or ablation of a portion of the target region immediately, if necessary. In some embodiments, the endoscope and/or ERCP device is combined with an ablation device having a flexible coil electrode at the end of a long metallic core, which electrode is deployable within a benign or malignant tumor cyst. The coil electrode assumed a coiled shape when deposited from a distal end of the device into the cyst cavity to cover the possible greatest amount of surface area therewithin. A radiofrequency source then delivers radiofrequency energy to the target cyst via the coil thereof in an amount sufficient to ablate at least a portion of the cyst or, alternatively, in an amount sufficient to heat the cyst to remodel and/or prevent its continued growth. In one implementation, the coil electrode is combined with an EUS FNA needle to allow physicians to treat the tumor cyst immediately after drainage and/or biopsy of the cyst. The combined system thus permits simultaneously assessing and treating the cancerous tissue, thereby reducing anxiety, complications or side effects associated with typical endoscopic examinations or ERCP procedures. Additionally, devices in accordance with the current invention are advantageously inexpensive and easy to operate. 
         [0006]    In one aspect, the present invention relates to an ablation device insertable into a target tissue that includes a core probe, a coil at the distal end of the core probe and a sheath catheter enclosing the core probe and the coil. The coil has a first shape when constrained within the sheath and a second shape once it extended through a distal end of the sheath catheter. In various embodiments, the first shape is straight, the second shape is one or more of an apex vortex shape, a spiral shape, or a J-shape. The coil optionally includes a shape memory material, while the sheath optionally includes an insulating material and the device optionally includes a handle which houses a radiofrequency source. The device also optionally includes a mechanical component that is connected to the sheath catheter and permits manipulation of the position and/or length of the sheath catheter. The mechanical component may also or additionally permit manipulation of the position of the coil. In some embodiments, the ablation device is configured to be inserted through a working channel of an endoscope or ERCP device and/or to be visible by ultrasound. 
         [0007]    In yet another aspect, the invention relates to methods of treating a patient which include inserting a biopsy needle into a lesion, deploying a coil electrode through the needle into the lesion, and delivering radiofrequency energy to the lesion, thereby heating or ablating the lesion and/or the surrounding tissue. In various embodiments, the biopsy needle is suitable for fine needle ablation, the cyst is a pancreatic cyst, the coil electrode comprises a wire and deploying the coil electrode comprises advancing about 5-10 inches of the length of the wire through the distal end of the needle into the cyst. The method may also include ultrasound guided endoscopic placement of the needle and/or aspiration of fluid or tissue from the lesion. In some cases, deployment of the coil electrode and delivery of radiofrequency to the lesion is based on an assessment of a predetermined characteristic, such as macroscopic characteristic associated with malignancy, a cytological characteristic associated with malignancy, a histological characteristic associated with malignancy, expression of a protein associated with malignancy, or the presence of a nucleic acid associated with malignancy. A characteristic “associated with malignancy” is, more generally, any characteristic that would be relied upon by a medical professional to make a definitive or tentative conclusion that a particular lesion is, or may become, malignant. 
         [0008]    Reference throughout this specification to “one example,” “an example,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example of the present technology. Thus, the occurrences of the phrases “in one example,” “in an example,” “one embodiment,” or “an embodiment” in various places throughout this specification are not necessarily all referring to the same example. Furthermore, the particular features, routines, steps, or characteristics may be combined in any suitable manner in one or more examples of the technology. The terms “substantially” and “approximately” mean ±10% and, in some embodiments, within ±5%. The headings provided herein are for convenience only and are not intended to limit or interpret the scope or meaning of the claimed technology. 
         [0009]    The phrase “and/or,” as used herein should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and/or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. 
         [0010]    This specification makes repeated reference to cysts, but it will be understood that these references are exemplary and are not necessarily limiting. For clarity, devices, systems and methods of the invention are useful in treating cysts as well as structures not delineated by a clear margin or membrane such as pseudocysts, abscesses and, more generally, any void or portion of a void or lumen within the body of a patient where treatment or ablation of tissue adjoining the void or lumen is desired. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, with an emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: 
           [0012]      FIG. 1A  is a cross sectional view of an endoscope; 
           [0013]      FIGS. 1B and 1C  schematically depict an ablation device integrated with the endoscope in accordance with various embodiments of the invention; 
           [0014]      FIGS. 1D and 1E  schematically depict an ablation device integrated with a surgical instrument in accordance with various embodiments of the invention; 
           [0015]      FIGS. 2A-2C  schematically depict the ablation device in accordance with various embodiments of the invention; 
           [0016]      FIG. 3A  schematically depicts the ablation device in accordance with an embodiment of the invention; 
           [0017]      FIGS. 3B and 3C  schematically depict operational mechanisms of the ablation device in accordance with various embodiments of the invention; and 
           [0018]      FIGS. 4A-4E  schematically depict exemplary shapes of a coil implemented in the ablation device in accordance with various embodiments of the invention; 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Refer first to  FIG. 1A , which illustrates an endoscope  100  typically including a catheter  102  having optical fibers  104  and multiple long, narrow working channels  106 ; the overall outer diameter D ranging from 5 mm to 15 mm is constrained by the limited dimensions of the body cavity opening (e.g., throat, intestine, trachea). The working channels  106  may include air and/or water channels that provide an airtight or watertight internal compartment for components such as electrical wiring and controls to be integrated therein, thereby protecting the components from exposure to patient secretions during use as well as facilitating submersion of the endoscope for cleaning and subsequent disinfection. The endoscope  100  generally includes a light source (such as a light-emitting diode), a halogen light source, or a metal halide light source)  108  that emits light via the optical fibers  104  to the distal (insertion) end of the catheter  102 . Referring to  FIG. 1B , in various embodiments, a tumor ablation device  110  is inserted into at least one working channel  106  to facilitate ablation of tumor tissue (such as a tumor cyst) at a target site. Alternatively, referring to  FIG. 1C , the tumor ablation device  110  may be attached to or joined to the endoscope  100  to form a single device. 
         [0020]    Referring to  FIG. 1D , in various embodiments, the tumor ablation device  110  is disposed within and/or capable of being deployed from a lumen  112  of a surgical instrument  114 , such as an FNA needle. A surgical instrument  114  suitable for use with the tumor ablation device may have a gauge (“ga”) suitable for use in percutaneous or endoscopic needle aspiration, for example 25 ga, 23 ga, 22 ga, 19 ga, etc. The tumor ablation  110  device is preferably configured to fill part or all of the volume and shape of a cyst or other void for which ablation is desired. For example, the volume may be about 1 cubic centimeter (“cc”) and may be, for example, substantially spherical, oblate, discoid, ovoid, ellipsoid, or irregular. Again, the tumor ablation device may be attached to or joined to the surgical instrument  114  to form an integrated single device as depicted in  FIG. 1E . Utilization of the ablation device  110  with the surgical instrument  114  enables the physician to treat the tumor cyst immediately after, for example, draining the cyst, if desired. 
         [0021]      FIGS. 2A-2C  depict various exemplary tumor ablation devices  210  in accordance with various embodiments of the current invention. The ablation device  210  may include a central core (or a radiofrequency probe)  212  and a coil  214  at the distal end thereof. The coil  214  may be an extension of the central core  212  ( FIG. 2A ) or may attach to the central core  212  using, for example, a weld ( FIG. 2B ). It should be noted that the terms “distal” and “proximal,” as used herein, are intended to refer to a direction away from (distal) and towards (proximal) a user of the device. In some embodiments, the central core  212  is preferably made of a conductive material which is stiff enough to push the coil  214  out of the distal end of the ablation device  210  but flexible enough to enable the physician to guide the coil  214  to the target region. 
         [0022]    The coil  214 , in preferred embodiments, includes one or more metals or metal alloys, such as platinum, a platinum alloy (e.g., platinum-tungsten alloy), or stainless steel. In a preferable embodiment, the coil  214  is made of a shape-memory material, such as Nitinol. Because a shape-memory material “remembers” its original, cold-forged shape and can be deformed substantially and still return to that shape, one of the advantages of using a shape-memory material is the high level of recoverable plastic strain that can be included. The maximum recoverable strain the shape-memory material can hold without permanent damage may be, for example, 8%, much larger than conventional steels with a maximum strain of, e.g., 0.5%. Therefore, the shape-memory material can be used to provide the coil  214  with a permanent shape, which the coil  214  assumes when in an unstressed configuration. This advantageously permits the coil  214  to be drawn into the surgical instrument prior to deployment, and to be bent, curved, etc. as the surgical instrument 
         [0023]    The coil  214  is generally made from a narrow gauge (e.g. 1/1000″- 1/100″ or 0.00254 cm-0.0254 cm) wire with a length of between 5 and 10 inches (12-25 cm), so that, when the coil  214  is deployed, the cyst is filled with a length of coil that is sufficient to achieve contact with or proximity to substantially of the wall of the cyst to be treated. Those of skill of art will appreciate that a substantial length of coil is used to fill or partially fill the volume of a cyst. For example, to fill a volume of about 1 cc, a length of wire ranging between 5 and 10, 10 and 15, 15 and 20 and 20 or more cm may be inserted into the cyst. In various embodiments, the wire forming the coil  214  has a length of 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm or more. One or more of the ablation device  210 , endoscope or ECRP device  100  or needle  114  preferably has a length sufficient to accommodate the full retracted length of the wire coil  214  and the central core  212 . As explained below, the wire may remain coiled when it is retracted into the ablation device  210  or it may be straightened out. In some instances, when the coil is retracted the wire is straightened in one portion of the ablation device  210  while it is coiled in another portion of the ablation device  210 . 
         [0024]    In various embodiments, the ablation device  210  further includes a sheath catheter  216  to enclose the central core  212  and the coil  214  therewithin. The sheath catheter  216  is preferably made of an insulating material. Additionally, the sheath catheter  216  may have a very small outer diameter (e.g., ˜2 millimeters) such that the entire ablation device  210  is insertable into the working channel  106  of the endoscope  100  or the lumen  112  of the surgical instrument  114 . The coil  214  may be constrained in a coiled form within the sheath catheter  216  as depicted in  FIGS. 2A and 2B . Alternatively, the coil  214  may be straightened in the sheath catheter  216  for shipping ( FIG. 2C ) and furled into the coiled form upon exiting the sheath catheter  216  or being deployed in the target tumor tissue. Delivering the coil  214  using an unfurled form in the sheath catheter  216  advantageously reduces the required outer diameter of the sheath catheter  216 , thereby allowing the ablation device  210  to be easily inserted into the working channel  106  of the endoscope  100  or the, lumen  112  of the surgical instrument  114 . Accordingly, the coil  214  may have a temporary shape and a permanent shape: The coil  214  exhibits its temporary shape when being constrained within the sheath catheter  216 . As the coil  214  exits the sheath catheter  216 , the coil  214  is released from the temporary shape and exhibits its permanent shape. The temporary shape and permanent shape may be the same or different. 
         [0025]    Referring to  FIGS. 3A-3C , in some embodiments, the sheath catheter  216  interfaces with a handle  302  that, in turn, connects to a radiofrequency source  304  such that the proximal end of the central core  212  is electrically connected to the radiofrequency source  304  via, for example, an electrical connector  306 . This therefore allows the radiofrequency source  304  to directly deliver ablation energy to the coil  214  for treating the target tumor cyst. The radiofrequency energy delivered to the cyst is sufficient to ablate the tumor tissue and eliminate or slow down the growth thereof. Alternatively, the radiofrequency energy is sufficient only to heat the tissue without ablating it. The handle  302  may also include a mechanical component  308  for facilitating deployment of the coil  214 . In one implementation, the mechanical component  308  is connected to the sheath catheter  216  for controlling the position and/or length thereof. For example, the component  308  may retract the sheath catheter  216  in a direction  310  to a positive stop (not shown) located at the proximal end, thereby exposing the coil  214  to the target cyst as depicted in  FIG. 3B . In another implementation, the mechanical component  308  is connected to the central core  212  for manipulating the position of the coil  214 . For example, the component  308  may push the central core  212  in a direction  312  passing the sheath catheter  216  (that may have a fixed position) to the distal end, thereby exposing the coil  214  as depicted in  FIG. 3C . The mechanical component  308  may be located inside or outside the handle  302 . In addition, exposing the coil  214  outside the delivery sheath catheter  216  using the approaches as described above are exemplary embodiments, any other means that is suitable for exposing the coil  214  to the target tumor tissue is within the scope of the current invention. In one embodiment, the handle  302  is sized and shaped to be grasped by the physician. 
         [0026]    During operation, an operator (e.g. a physician) first gains access to the cyst to make a diagnosis using, for example, an endoscope or ERCP device, and/or perform a procedure, such as drainage or biopsy, using a surgical instrument (e.g., an FNA needle). If an immediate treatment is necessary, the physician may insert the ablation device  210  into the lumen  112  of the FNA needle  114  or the working channel  106  of the endoscope  100  and deploy the coil  214  within the cyst. The physician may then activate the radiofrequency source  304  to deliver sufficient energy to the coil  214  for treating the tumor cyst. In various embodiments, the ablation device  210  is integrated with the endoscope or surgical instrument and form a single device. The physician may perform the tumor treatment simply by deploying the coil  114  into the tumor cyst and subsequently switching on the radiofrequency source  304  to deliver ablation energy to the target cyst. When a treatment goal is achieved (i.e., ablating at least a portion of tumor tissue or eliminating or slowing down the growth thereof), the physician may determine to stop the treatment. In one embodiment, the coil  214  is retracted to the sheath catheter  216  using the mechanical component  308  in a manner as described above and re-constrained within the sheath catheter  216 . The ablation device  210  (and the endoscope  100  or surgical instrument  114 ) may then be removed from the patient&#39;s body. 
         [0027]    The coil  214  may have various permanent shapes depending on the structure of the target cyst. In a preferable embodiment, the permanent shape is capable of “packing” the space of the cyst&#39;s cavity such that the coil  214  is in contact with the maximum possible surface area thereof. This ensures that the cyst can be efficiently and effectively ablated or treated using the deployed coil  204 . Referring to  FIGS. 4A-4D , the coil  214  may have a dual apex vortex shape (or “ball” shape), a single apex vortex shape (or “cone” shape), a complex shape (or “bird&#39;s nest” shape), or a spiral shape as depicted in  FIGS. 4A. 4B ,  4 C, and  4 D, respectively. In one embodiment, referring to  FIG. 4E , the coil  214  has a permanent shape in the form of a “J,” which may be used, for example, to fill remaining space in the cavity that was not filled by other coils. For example, the physician may hook the curved portion of the J coil into a coil that has been deployed within the cyst and then shape the straighter portion of the J coil to fill the space within the cavity. The shape of the coil  214  is not limited to the above-identified shapes; for example, the coil  214  may have a triangular, rectangular, octagonal or other shape. Any shape that is suitable for being inserted into a tumor cyst for ablation purposes is within the scope of the current invention. In addition, the coil  214  may include any number of different shapes, which may, again, depend on the structure of the cyst. 
         [0028]    Finally, implants utilizing coil electrodes according to the present invention may be used in bipolar or monopolar configurations, as will be appreciated by those of skill in the art. 
         [0029]    Certain embodiments of the present invention were described above. It is, however, expressly noted that the present invention is not limited to those embodiments, but rather the intention is that additions and modifications to what was expressly described herein are also included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein were not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations were not made express herein, without departing from the spirit and scope of the invention. In fact, variations, modifications, and other implementations of what was described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention. As such, the invention is not to be defined only by the preceding illustrative description.