Patent Publication Number: US-2021186607-A1

Title: Eus access device with electrosurgery-enhanced puncture

Description:
PRIORITY CLAIM 
     The present disclosure claims priority to U.S. Provisional Patent Application Ser. No. 62/953,307 filed Dec. 24, 2019; the disclosure of which is incorporated herewith by reference. 
    
    
     FIELD 
     The present disclosure relates to endoscopic ultrasound (EUS) access devices for accessing anatomical structures e.g. the pancreatico-biliary tree. 
     BACKGROUND 
     Endoscopic ultrasound (EUS) access procedures, e.g., under ultrasound guidance, may be used to access anatomical structures such as the pancreatico-biliary tree and pancreatic pseudocysts. A pancreatico-biliary access procedure, such as a procedure to insert a stent and bypass a blockage, may differ from other types of access procedures in that the target anatomy is exceedingly narrow. Many EUS access devices lack the maneuverability for biliary procedures and, even when possessing sufficient maneuverability, may encounter other difficulties. For example, devices with long, thin sharps may easily make an initial puncture hole, but risk extending the sharp too far, e.g. until the other side of the bile duct or other non-targeted tissue is penetrated. 
     Additionally, if an access cannula rides along the outer diameter of the sharp during the initial puncture, a long sharp may not bring the access cannula far enough distally into the puncture hole to maintain access to the duct after the sharp is removed. In another example, devices with shorter, thicker sharps may pose less of a risk for unintended punctures, but may make the initial puncture more difficult, e.g., by increasing the force required to puncture the target tissue. In still another example, a blunt access cannula may fail to follow the sharp tip into the puncture hole. 
     SUMMARY 
     The present disclosure relates to a device which includes a catheter including a lumen extending therethrough, the catheter being sized and shaped to extend through an endoscopic shaft to a target tissue within a living body; a puncturing device sized and shaped to extend through the lumen of the catheter and distally out a distal end of the catheter; and at least one of the catheter and the puncturing device including an electrode formed thereon, the electrode being energizable from a handle of the device so that, when the puncturing device is extended distally out the distal end of the catheter, the electrode may be energized as the device punctures the target tissue. 
     In an embodiment, the distal end of the catheter is biased to assume a J-shape curve when unconstrained. 
     In an embodiment, the distal end is rotatable about a longitudinal axis of the catheter to direct a distal opening of the distal end in a desired direction within the target tissue. 
     In an embodiment, when the puncturing device punctures the target tissue, the distal end of the catheter follows the puncturing device into the target tissue. 
     In an embodiment, the device further includes an electrosurgical sheath longitudinally slidable along an exterior of the catheter, the electrosurgical sheath having an electrosurgical tip for dilating an access hole created by the puncturing device in the target tissue. 
     In an embodiment, when the puncturing device extends into the distal end of the catheter, the distal end of the catheter is straightened. 
     In an embodiment, an electrode is formed at the distal end of the catheter. 
     In an embodiment, a proximal portion of the catheter between the distal end of the catheter and a distal end of the handle is formed from a non-conductive material, further comprising a conducting wire connecting the electrode to the handle. 
     In an embodiment, the device further includes an electrode formed at a distal end of the puncturing device. 
     In an embodiment, an electrode is formed at a distal end of the puncturing device. 
     In an embodiment, the device further includes an insulation layer extending along the puncturing device from a proximal end of the electrode to a proximal end of the puncturing device. 
     In an embodiment, the handle further includes a length adjust; a sharp hub; a puncture actuator advancing the puncturing device and the catheter distally out of a sheath of the device; an electrosurgical sled slidably mounted over the puncture actuator to advance the sheath distally over the catheter to apply energy to the target tissue using an electrode formed on the sheath; a puncture actuator lock; an electrosurgical sled lock to lock a position of the sheath in a desired position relative to the catheter; and a first generator connection on the electrosurgical sled configured to couple to a source of electric energy. 
     In an embodiment, the handle further includes a second generator connection on the puncture actuator configured to couple to a source of electric energy and/or a third generator connection on the sharp hub configured to couple to a source of electric energy 
     The present disclosure also relates to a system which includes a catheter including a lumen extending therethrough, the catheter being sized and shaped to extend through an endoscopic shaft to a target tissue within a living body; a puncturing device sized and shaped to extend through the lumen of the catheter and distally out a distal end of the catheter; and at least one of the catheter and the puncturing device including an electrode formed thereon, the electrode being energizable from a handle of the device so that, when the puncturing device is extended distally out the distal end of the catheter, the electrode may be energized as the device punctures the target tissue; and an electrosurgical sheath longitudinally slidable along an exterior of the catheter, the electrosurgical sheath having an electrosurgical tip for dilating an access hole created by the puncturing device in the target tissue. 
     In an embodiment, the distal end is rotatable about a longitudinal axis of the catheter to direct a distal opening of the distal end in a desired direction within the target tissue. 
     Furthermore, the present disclosure relates to a method which includes extending a puncturing device through a lumen of a catheter, the catheter being sized and shaped to extend through an endoscopic shaft to a target site within a living body, at least one of the catheter and the puncturing device including an electrode formed thereon; energizing the electrode; puncturing target tissue with the puncturing device; advancing the catheter distally through an access hole created by the puncturing device in the target tissue; and withdrawing the puncturing device proximally through the lumen past a distal end of the catheter. 
     In an embodiment, the method further includes sliding an electrosurgical sheath along an exterior of the catheter, the electrosurgical sheath having an electrosurgical tip; positioning the electrosurgical tip in contact with tissue surrounding the access hole; and applying an electrical current to dilate the access hole. 
     In an embodiment, the method further includes locking the electrosurgical sheath in a desired position relative to the catheter. 
     In an embodiment, the method further includes rotating the distal end of the catheter about a longitudinal axis of the catheter to direct a distal opening of the distal end of the catheter in a desired direction within the target tissue. 
     In an embodiment, the electrode is formed at the distal end of the catheter. The method further includes energizing an electrode formed at a distal end of the puncturing device, prior to puncturing the target tissue with the puncturing device. 
    
    
     
       BRIEF DESCRIPTION 
         FIGS. 1 a -1 b    show the distal end of an endoscopic access device. 
         FIG. 2 a    shows an endoscopic access device with a long sharp. 
         FIG. 2 b    shows an endoscopic access device with a short sharp. 
         FIG. 2 c    shows an endoscopic access device with an excessive displacement formed between the sharp and the J-tip. 
         FIG. 3  shows a distal tip of a microcatheter having an exposed metal end that may be energized for hot puncturing in an EUS access procedure. 
         FIG. 4  shows a sharp having an exposed metal end that may be energized for hot puncturing in an EUS access procedure. 
         FIG. 5  shows a handle for controlling an EUS access procedure. 
         FIG. 6  shows a fine needle aspiration (FNA) needle having a blunted end that may be energized for hot puncturing in an EUS access procedure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure 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 exemplary embodiments describe EUS access devices with a hot sharp and/or J-tip for effective puncturing and placement of the J-tip with low puncture forces and lower risk of losing access to the target tissue. In the present disclosure, the term “hot” refers to an element that is electrosurgically activated. Hot elements are designed so that, when activated, they pass a current through tissue, while remaining relatively unheated as they run a current through the target tissue so that electrical resistance of the target tissue causes the target tissue to heat and boil, thus enabling the target tissue to be cut and dilated. In the present disclosure, the term “cold” refers to an element that is not electrosurgically activated. 
       FIGS. 1 a -1 b    show an exemplary EUS access device  100  including a microcatheter  102  (i.e., access cannula) with a flexible distal tip  104  biased to assume, when unconstrained, a natural J-shape (J-tip). A puncturing element  106  with a pointed tip (i.e., the sharp) is advanced through the lumen of the microcatheter  102  so that the flexible J-tip  104  is straightened via the stiffness of the sharp  106  until the sharp  106  extends distally out the distal end of the J-tip  104  by a desired distance so that the sharp  106  may be used to puncture target tissue and the sharp  106  and J-tip  104  may be advanced together into the target anatomy. 
     The distance  108  by which the distal tip of the sharp  106  protrudes distally beyond the distal end of the J-tip  104  when the sharp  106  is inserted therein is referred to as the “setback.” After the J-tip  104  and sharp  106  have been advanced into the target anatomy as desired, the sharp  106  is withdrawn proximally out of the J-tip  104  freeing the J-tip  104  to return to its curved J-shape, as shown in  FIG. 1 b   . A guidewire may then be inserted through the lumen of the microcatheter  102  and out of the distal end of the J-tip  104  into the target anatomy. Before, while, or after the guidewire is inserted into the microcatheter  102 , the J-tip  104  may be rotated to point a distal opening of the J-tip  104  in a desired direction within the target anatomy. 
     For example, where the target anatomy is a bile duct, the J-tip  104  may be rotated so that the distal opening of the lumen of the microcatheter  102  faces either upstream in the bile duct or downstream toward an outlet of the bile duct into the small intestine. When the J-tip  104  is oriented as desired, the guidewire is passed through the microcatheter  102  to exit the opening at the distal end of the J-tip  104  and is extended out of the J-tip  104  in the desired direction along the bile duct by a desired distance. At this point, a flexible electrosurgical sheath  110  with an electrosurgical tip  112  may be advanced over the microcatheter  102  and the J-tip  104  to dilate a hole by which the microcatheter  102  exited the small intestine and a hole by which the microcatheter  102  entered the target bile duct. The electrosurgical tip may dilate the access holes(s) (fistula) to e.g. 5-11 Fr. As would be understood by those skilled in the art, an electrode of the electrosurgical tip may be activated when this tip is located at the entrance to and within hole to cut and widen the holes to facilitate access to the target anatomy for further procedures (e.g., placing a stent therein to bypass a blockage). 
     The sharp  106  is typically used to make a starter hole in the anatomy through which the wider diameter J-tip  104  may be pushed, so that when the sharp  106  is removed the J-tip  104  is firmly inserted through the puncture hole within the target anatomy. However, various complications may arise when performing this operation. 
     For example, an access device  200  with a long, thin sharp  201 , as shown in  FIG. 2 a   , may puncture the tissue  203  easily, i.e., reduce puncture forces necessary to make the hole. However, the long setback between the distal tip of the sharp  201  and the distal end of the J-tip  202  requires the sharp to be pushed further into the tissue  203  before the J-tip  202  is firmly inserted in the puncture hole. Thus, using a long, thin sharp  201  risks pushing the sharp  201  too far distally and inadvertently puncturing tissue  204  distal to the initially punctured tissue  203 . Conversely, if the long sharp  201  is not pushed far enough to firmly entrench the J-tip  202 , the J-tip  202  may recede from and fall out of the puncture hole when the sharp  201  is removed. 
     In another example, an access device  210  with a shorter, thicker sharp  211 , as shown in  FIG. 2 b   , may carry less risk of unintentionally puncturing the tissue  214  distal to the initially punctured tissue  213 , or having the J-tip  212  fall out of the puncture hole. However, the force required to puncture target tissue with a device including such a thickened sharp  211  are increased as compared to those required with a long, thin sharp. 
     In still another example, an access device  220 , as shown in  FIG. 2 c   , may have a J-tip  222  that catches on the anatomy walls as the sharp  221  is advanced through the tissue  223 , resulting in a displacement between the sharp tip  221  and the J-tip  222  and potentially pushing the tissue  223  distally as the J-tip  222  is forced against the tissue wall (i.e. tenting). Tenting may occur when a blunt or poorly tapered J-tip is used. However, using a sharper-edged J-tip may risk damaging surrounding tissue when the J-tip is rotated within the duct to direct the guidewire. 
     The exemplary embodiments describe EUS access devices with one or more energized features for hot puncturing that address the aforementioned issues. An electrosurgical generator, such as an Erbe generator, may be used to apply an RF cutting current to the device to allow the puncturing tip(s) to pass easily into the tissue with low puncture forces. The devices may be substantially similar to the device described in  FIGS. 1 a -1 b   , with modifications to be described below. 
       FIG. 3  shows a distal tip  300  (J-tip) of a microcatheter (in its straightened configuration) having an exposed metal end  302  that may be energized for hot puncturing in an EUS access procedure. The metal end  302  is blunt to minimize trauma to the surrounding tissue as the J-tip  300  (in its curved configuration) is rotated within a duct to direct a guidewire as desired. Any sharp may be used with the distal tip  300  as would be understood by those skilled in the art. However, a shorter sharp may be used without increasing the required puncture forces. As noted above, the use of a cold, blunt J-tip with a short sharp requires increased puncture forces. However, a hot, blunt J-tip has been shown to puncture with relatively low puncture forces. In this embodiment, the hot, blunt J-tip may have a minimum setback of approximately 0.5 mm. 
     When the microcatheter is entirely metal, the entirety of the microcatheter with the exception of the exposed metal end  302  is insulated to prevent the heating or cutting of non-targeted tissue (i.e., tissue other than that at the target site). The exposed metal end  302  may, for example, be less than ˜1 mm long to minimize thermal damage to the target site during the cutting. The exposed metal end  302  of the hot J-tip  300  may also be wired to the handle, and the remainder of the microcatheter may be formed of a different, non-conductive material eliminating the need for a separate electrically insulative coating. 
       FIG. 4  shows a sharp  400  having an exposed metal end  402  that may be energized for hot puncturing in an EUS access procedure. The exposed metal end  402  may be a short, sharpened tip, or may be relatively blunt. When the metal end  402  is sharpened the sharp  400  may be used for cold puncture as well. However, if the attempted cold puncture is unsuccessful, a user has the option to energize the exposed metal end  402  for a hot puncture. 
     Similarly to the hot J-tip  300 , the hot sharp  400  may have a flexible shaft of the same conductive material (e.g. metal) as the exposed metal end  402  yet be insulated along its length (with the exception of the exposed metal end  402 ). If the access cannula being used with the sharp  400  is not intended to have a hot J-tip, the J-tip may be insulated to prevent conduction of electricity from the sharp  400  through the J-tip. Alternately, the J-tip may not be insulated and the access device will have both a hot sharp and a hot J-tip. In such a case, only one of the J-tip or the sharp need be connected to the electrosurgical generator (by wire, or otherwise) to effectively energize both tips. 
     Although a hot sharp cuts well enough to allow a blunt, cold J-tip to pass through the fistula, energizing both of the tips may further reduce puncture forces. However, choosing which one or both of the J-tip and sharp to energize may depend on the nature of the intervention. For example, a hot J-tip has been shown to make a larger fistula than a cold J-tip. A larger fistula would not affect a procedure such as a stent implant, considering the fistula will need to be made larger still with an electrosurgical dilator prior to implanting the stent. However, for a procedure where a smaller hole is desired (e.g., a rendezvous procedure), an energized sharp with a cold J-tip may be preferred over energizing both the sharp and the J-tip. 
     In an alternate embodiment, a hot blunt stylet may be used instead of a sharp. The stylet has a blunt distal end, as opposed to the sharp which has a sharpened distal end. In this embodiment, the stylet and the J-tip may have a very short setback, e.g. 2 mm, to ensure that when the stylet tip is passed into the duct the access cannula will pass into the duct as well. This embodiment allows for targeting of smaller tissues as there is lower risk of the tip extending to the opposite side of the duct and inadvertently puncturing the opposite side. 
     The aforementioned embodiments may be implemented via an endoscope, with the device having a handle for controlling the endoscopic procedure. 
       FIG. 5  shows a handle  500  for controlling an EUS access procedure. The handle  500  extends from a proximal sharp hub  502  to a distal collar  504  that attaches to a coupling at a proximal end of an endoscope shaft. The sharp hub  502  is connected to the sharp such that the sharp hub  502  can be pulled to withdraw the sharp from the device. The sharp hub  502  includes a generator connection  520  at which a source of electrical energy may be coupled to the device. The handle  500  includes a length adjust  506  via which a user can adjust a length of the handle  500  so that, when coupled to an endoscope, a length of the electrosurgical sheath will extend to a desired distance distally beyond a distal end of the endoscope (i.e., the length adjust may be used to achieve an extension of the device out the endoscope). The handle  500  further includes a puncture actuator  508  that is slidable over a base  512  of the handle  500  so that, when unlocked via a puncture actuator lock  510 , the J-tip and the sharp are advanced distally out of a sheath (e.g., electrosurgical sheath  110  shown in  FIG. 1 ) so that the J-tip and the sharp can penetrate target tissue to a desired depth. The puncture actuator  508  includes a generator connection  522  at which a source of electrical energy may be coupled to the device. 
     The handle  500  further includes an electrosurgical sled  514  slidably mounted over the puncture actuator  508  so that the sheath can be advanced distally over the J-tip to bring an electrosurgical tip (e.g., electrosurgical tip  112  shown in  FIG. 1 ) at the distal end of the sheath into contact with target tissue so that the tissue may be treated by the application of energy from the tip (e.g., to cut and dilate tissue around an opening formed through a wall of the gastrointestinal tract and an entry opening into a target pancreatico-biliary lumen). The electrosurgical sled  514  includes a generator connection  516  at which a source of electrical energy may be coupled to the device. The electrosurgical sled  514  is maintained in a desired position over the puncture actuator  508  via an electrosurgical sled lock  518 . Similarly to the puncture actuator lock  510 , the electrosurgical sled lock  518  includes a projection that may engage a geared surface on the base  512  until the corresponding lock is depressed to disengage the connection with the base  512 , permitting the puncture actuator  508  or the electrosurgical sled  514  to slide over the base  512 . 
     The generator connection  516  provides the coupling to electrical energy that may be transmitted to the electrosurgical sled  514 . The generator connections  520  and  522  would provide energy to each of the metal end  402  of the sharp and the metal end  302  of the J-tip microcatheter, respectively, in the manner described above. The base  512  may have depth indicators thereon, providing greater control of the puncture depth of the sharp/J-tip and the electrosurgical sheath length. As indicated previously, the ideal depth of the puncture may vary for different procedures and for different sharp/J-tip configurations. Thus, the handle  500  has precise puncture depth controllability compatible with different access devices having different puncture depths. 
       FIG. 6  shows a fine needle aspiration (FNA) needle  600  having a blunted end  602  that may be energized for hot puncturing in an EUS access procedure. The FNA needle  600  has a lumen for a guidewire to extend through. A blunted, as opposed to sharp, needle allows for easier guidewire directionality with less risk of skiving the guidewire. The blunted end  602 , despite being blunt, is able to puncture anatomy when energized. 
     Each of the aforementioned energized puncturing features may be actuated via an electrosurgical plug extending from or built into the endoscope handle. The hot tip feature may be actuated at any time during the endoscopic intervention. Thus, a clinician may begin a procedure using e.g. a cold sharp tip and, if the cold puncture is unsuccessful, actuate the hot tip and perform a hot puncture. 
     It will be appreciated by those skilled in the art that changes may be made to the embodiments described above without departing from the inventive concept thereof. It should further be appreciated that structural features and methods associated with one of the embodiments can be incorporated into other embodiments. It is understood, therefore, that this invention is not limited to the particular embodiment disclosed, but rather modifications are also covered within the scope of the present invention as defined by the appended claims.