Patent Description:
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.

<CIT> discloses an apparatus for causing tissue ablation at a specified therapeutic site in the body of a patient. The apparatus comprises a catheter and an ablation device with at least one energy delivery element for inducing tissue ablation. The catheter comprises a lumen and the ablation device is capable of being coaxially positioned within the lumen and being advanced distally out of the lumen of the catheter.

<CIT> discloses a puncture instrument for punctured high frequency treatments. The puncture instrument essentially includes a guide, a puncture needle member with a sharp-pointed needle head provided with a high frequency electrode. The needle member is received in the guide tube and the sharp-pointed needle head is protrudable out of the guide tube to penetrate into a target intracorporeal portion to be treated.

<CIT> discloses a device for ablating tissue comprising a guide element and a rigid elongate tubular member passing over the guide element. The rigid tubular member comprises an electrode to thermally ablate tissue.

<CIT> discloses an electrosurgical device comprising an electrically conductive elongate member.

<CIT> discloses an electro-coagulation device constructed for passage into a living body to perform therapy on a selected region of body tissue.

The methods described below are not part of the claimed invention, but are useful for the general understanding of the invention.

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. 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, 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, 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, not part of the claimed invention as such, 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.

Furthermore, the present disclosure relates to a method, not part of the claimed invention as such, 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.

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.

<FIG> show an exemplary EUS access device <NUM> including a microcatheter <NUM> (i.e., access cannula) with a flexible distal tip <NUM> biased to assume, when unconstrained, a natural J-shape (J-tip). A puncturing element <NUM> with a pointed tip (i.e., the sharp) is advanced through the lumen of the microcatheter <NUM> so that the flexible J-tip <NUM> is straightened via the stiffness of the sharp <NUM> until the sharp <NUM> extends distally out the distal end of the J-tip <NUM> by a desired distance so that the sharp <NUM> may be used to puncture target tissue and the sharp <NUM> and J-tip <NUM> may be advanced together into the target anatomy.

The distance <NUM> by which the distal tip of the sharp <NUM> protrudes distally beyond the distal end of the J-tip <NUM> when the sharp <NUM> is inserted therein is referred to as the "setback. " After the J-tip <NUM> and sharp <NUM> have been advanced into the target anatomy as desired, the sharp <NUM> is withdrawn proximally out of the J-tip <NUM> freeing the J-tip <NUM> to return to its curved J-shape, as shown in <FIG>. A guidewire may then be inserted through the lumen of the microcatheter <NUM> and out of the distal end of the J-tip <NUM> into the target anatomy. Before, while, or after the guidewire is inserted into the microcatheter <NUM>, the J-tip <NUM> may be rotated to point a distal opening of the J-tip <NUM> in a desired direction within the target anatomy.

For example, where the target anatomy is a bile duct, the J-tip <NUM> may be rotated so that the distal opening of the lumen of the microcatheter <NUM> faces either upstream in the bile duct or downstream toward an outlet of the bile duct into the small intestine. When the J-tip <NUM> is oriented as desired, the guidewire is passed through the microcatheter <NUM> to exit the opening at the distal end of the J-tip <NUM> and is extended out of the J-tip <NUM> in the desired direction along the bile duct by a desired distance. At this point, a flexible electrosurgical sheath <NUM> with an electrosurgical tip <NUM> may be advanced over the microcatheter <NUM> and the J-tip <NUM> to dilate a hole by which the microcatheter <NUM> exited the small intestine and a hole by which the microcatheter <NUM> entered the target bile duct. The electrosurgical tip may dilate the access holes(s) (fistula) to e.g. <NUM>-<NUM> 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 <NUM> is typically used to make a starter hole in the anatomy through which the wider diameter J-tip <NUM> may be pushed, so that when the sharp <NUM> is removed the J-tip <NUM> 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 <NUM> with a long, thin sharp <NUM>, as shown in <FIG>, may puncture the tissue <NUM> easily, i.e., reduce puncture forces necessary to make the hole. However, the long setback between the distal tip of the sharp <NUM> and the distal end of the J-tip <NUM> requires the sharp to be pushed further into the tissue <NUM> before the J-tip <NUM> is firmly inserted in the puncture hole. Thus, using a long, thin sharp <NUM> risks pushing the sharp <NUM> too far distally and inadvertently puncturing tissue <NUM> distal to the initially punctured tissue <NUM>. Conversely, if the long sharp <NUM> is not pushed far enough to firmly entrench the J-tip <NUM>, the J-tip <NUM> may recede from and fall out of the puncture hole when the sharp 201is removed.

In another example, an access device <NUM> with a shorter, thicker sharp <NUM>, as shown in <FIG>, may carry less risk of unintentionally puncturing the tissue <NUM> distal to the initially punctured tissue <NUM>, or having the J-tip <NUM> fall out of the puncture hole. However, the force required to puncture target tissue with a device including such a thickened sharp <NUM> are increased as compared to those required with a long, thin sharp.

In still another example, an access device <NUM>, as shown in <FIG>, may have a J-tip <NUM> that catches on the anatomy walls as the sharp <NUM> is advanced through the tissue <NUM>, resulting in a displacement between the sharp tip <NUM> and the J-tip <NUM> and potentially pushing the tissue <NUM> distally as the J-tip <NUM> 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 <FIG>, with modifications to be described below.

<FIG> shows a distal tip <NUM> (J-tip) of a microcatheter (in its straightened configuration) having an exposed metal end <NUM> that may be energized for hot puncturing in an EUS access procedure. The metal end <NUM> is blunt to minimize trauma to the surrounding tissue as the J-tip <NUM> (in its curved configuration) is rotated within a duct to direct a guidewire as desired. Any sharp may be used with the distal tip <NUM> 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 <NUM>.

When the microcatheter is entirely metal, the entirety of the microcatheter with the exception of the exposed metal end <NUM> 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 <NUM> may, for example, be less than ~<NUM> long to minimize thermal damage to the target site during the cutting. The exposed metal end <NUM> of the hot J-tip <NUM> 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> shows a sharp <NUM> having an exposed metal end <NUM> that may be energized for hot puncturing in an EUS access procedure. The exposed metal end <NUM> may be a short, sharpened tip, or may be relatively blunt. When the metal end <NUM> is sharpened the sharp <NUM> 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 <NUM> for a hot puncture.

Similarly to the hot J-tip <NUM>, the hot sharp <NUM> may have a flexible shaft of the same conductive material (e.g. metal) as the exposed metal end <NUM> yet be insulated along its length (with the exception of the exposed metal end <NUM>). If the access cannula being used with the sharp <NUM> is not intended to have a hot J-tip, the J-tip may be insulated to prevent conduction of electricity from the sharp <NUM> 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. <NUM>, 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> shows a handle <NUM> for controlling an EUS access procedure. The handle <NUM> extends from a proximal sharp hub <NUM> to a distal collar <NUM> that attaches to a coupling at a proximal end of an endoscope shaft. The sharp hub <NUM> is connected to the sharp such that the sharp hub <NUM> can be pulled to withdraw the sharp from the device. The sharp hub <NUM> includes a generator connection <NUM> at which a source of electrical energy may be coupled to the device. The handle <NUM> includes a length adjust <NUM> via which a user can adjust a length of the handle <NUM> 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 <NUM> further includes a puncture actuator <NUM> that is slidable over a base <NUM> of the handle <NUM> so that, when unlocked via a puncture actuator lock <NUM>, the J-tip and the sharp are advanced distally out of a sheath (e.g., electrosurgical sheath <NUM> shown in <FIG>) so that the J-tip and the sharp can penetrate target tissue to a desired depth. The puncture actuator <NUM> includes a generator connection <NUM> at which a source of electrical energy may be coupled to the device.

The handle <NUM> further includes an electrosurgical sled <NUM> slidably mounted over the puncture actuator <NUM> so that the sheath can be advanced distally over the J-tip to bring an electrosurgical tip (e.g., electrosurgical tip <NUM> shown in <FIG>) 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 <NUM> includes a generator connection <NUM> at which a source of electrical energy may be coupled to the device. The electrosurgical sled <NUM> is maintained in a desired position over the puncture actuator <NUM> via an electrosurgical sled lock <NUM>. Similarly to the puncture actuator lock <NUM>, the electrosurgical sled lock <NUM> includes a projection that may engage a geared surface on the base <NUM> until the corresponding lock is depressed to disengage the connection with the base <NUM>, permitting the puncture actuator <NUM> or the electrosurgical sled <NUM> to slide over the base <NUM>.

The generator connection <NUM> provides the coupling to electrical energy that may be transmitted to the electrosurgical sled <NUM>. The generator connections <NUM> and <NUM> would provide energy to each of the metal end <NUM> of the sharp and the metal end <NUM> of the J-tip microcatheter, respectively, in the manner described above. The base <NUM> 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 <NUM> has precise puncture depth controllability compatible with different access devices having different puncture depths.

<FIG> shows a fine needle aspiration (FNA) needle <NUM> having a blunted end <NUM> that may be energized for hot puncturing in an EUS access procedure. The FNA needle <NUM> 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 <NUM>, despite being blunt, is able to puncture anatomy when energized.

Claim 1:
A device (<NUM>), comprising:
a catheter (<NUM>) including a lumen extending therethrough, the catheter (<NUM>) being sized and shaped to extend through an endoscopic shaft to a target tissue within a living body;
a puncturing device (<NUM>) sized and shaped to extend through the lumen of the catheter and distally out a distal end (<NUM>) of the catheter (<NUM>);
at least one of the catheter (<NUM>) and the puncturing device (<NUM>) including an electrode formed thereon, the electrode being energizable from a handle (<NUM>) of the device so that, when the puncturing device (<NUM>) is extended distally out the distal end of the catheter (<NUM>), the electrode may be energized as the device (<NUM>) punctures the target tissue; and
an electrosurgical sheath (<NUM>) longitudinally slidable along an exterior of the catheter (<NUM>), the electrosurgical sheath having an electrosurgical tip (<NUM>) for dilating an access hole created by the puncturing device (<NUM>) in the target tissue.