Patent Description:
Many endoscopic ultrasound (EUS) guidance procedures involve creating a puncture tract (e.g., fistula) through the tissue layer(s) of a target anatomy using a tissue-penetrating needle, advancing a guidewire through the tissue-penetrating needle to position a distal end of the guidewire within the target anatomy and then advancing a medical device with a circular electrosurgical tip over the guidewire to dilate the puncture tract. To effectively dilate the tissue layer(s) with minimal thermal damage (e.g., charring, burning, coagulation, etc.), the electrosurgical tip must deliver radiofrequency energy with sufficient current density through a low surface area profile. Due to these design criteria, conventional electrosurgical tips tend to be expensive and difficult to manufacture.

It is with these considerations in mind that a variety of advantageous medical outcomes may be realized by the devices, systems and methods of the present disclosure. <CIT> discloses an open-irrigated catheter system that includes a catheter body and a tip assembly, coupled to a distal end of the catheter body. The tip assembly includes an exterior wall that is conductive for delivering radio frequency (RF) energy for an RF ablation procedure, and that defines an interior region. The exterior wall includes a number of proximal irrigation ports and a number of distal irrigation ports. At least one fluid chamber is defined within the interior region and is in fluid communication with at least one of the proximal irrigation ports and the distal irrigation ports. At least one fluid lumen extends from a fluid source, through the catheter body, to the tip assembly, and is in fluid communication with the at least one fluid chamber.

In one aspect, the present disclosure relates to a medical device comprising a non-conductive base component defining a longitudinal axis and a lumen therethrough. A conductive material may be disposed on an outer surface of the non-conductive base component around a distal opening of the lumen. A conductive material may be disposed on an outer surface of the non-conductive base component along the longitudinal axis. The conductive material disposed around the distal opening may include a first layer of conductive material bonded to the non-conductive base component. The conductive material disposed along the longitudinal axis may include a second layer of conductive material bonded to the non-conductive base component. The first and second layers of conductive material may be sputter-coated onto the non-conductive base component.

In the described and other embodiments, one or more of the first and second layers of conductive material may be sputter-coated onto the non-conductive base component. A channel may be formed within the outer surface of the non-conductive base component along the longitudinal axis. The second layer of conductive material may extend through the channel. The first and second layers of conductive material may include titanium. The conductive material disposed around the distal opening may further include a third layer of conductive material bonded to the first layer of conductive material and the conductive material disposed along the longitudinal axis may include a fourth layer of conductive material bonded to the second layer of conductive material. The third and fourth layers of conductive material may be sputter-coated onto the respective first and second layers of conductive material. The third and fourth layers of conductive material may include niobium. The conductive material disposed around the distal opening may further include a fifth layer of conductive material bonded to the third layer of conductive material. The conductive material disposed along the longitudinal axis may include a sixth layer of conductive material bonded to the fourth layer of conductive material. The fifth layer of conductive material may include gold. The sixth layer of conductive material may include a nickel-copper alloy. The fifth and sixth layers of conductive material may be sputter-coated onto the respective third a fourth layers of conductive material. The fifth layer of conductive material may be brazed to the third layer of conductive material. The sixth layer of conductive material may be sputter-coated onto the fourth layer of conductive material. A distal portion of a conductive wire may be soldered to the sixth layer of conductive material.

In another aspect, the present disclosure relates to a system comprising a non-conductive base component attached to a distal end of an electrosurgical sheath. The non-conductive base component may include a conductive material applied around a distal opening of the non-conductive base component and a strip of conductive material applied along a longitudinal axis of the non-conductive base component. An access cannula may be disposable within a lumen of the electrosurgical sheath and extendable through the non-conductive base component.

In the described and other embodiments, one or more of the conductive material and the strip of conductive material may be applied via sputter-coating. A channel may be formed within an outer surface of the non-conductive base component along the longitudinal axis. The strip of conductive material may extend through the channel. The channel may be disposed within a distal portion of the electrosurgical sheath. A distal portion of a conductive wire may be disposed within the channel. The distal portion of the conductive wire may be bonded to the channel using solder. The conductive wire may extend along the electrosurgical sheath and a proximal end of the conductive wire may be connectable to an electrosurgical generator. A guidewire may be extendable through a lumen of the access cannula.

In yet another aspect, the present disclosure relates to a medical device comprising a non-conductive base component defining a longitudinal axis and a lumen therethrough. A first layer of conductive material may be disposed around an outer surface of the non-conductive base component in a spiral pattern. A second layer of conductive material may be disposed around an outer surface of the non-conductive base component in a spiral pattern. The first and second layers of conductive material may be electrically insulated from each other.

In the described and other embodiments, the first and second layers of conductive material may be the same. The first and second layers of conductive material may be different. The first and second layers of conductive material may be sputter-coated to the non-conductive base component.

The present disclosure is not limited to the particular embodiments described herein. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting beyond the scope of the appended claims. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs.

Although embodiments of the present disclosure are described with specific reference to an electrosurgical surgical tip comprising one or more layers of conductive metal(s) coated onto a non-conductive ceramic base using physical vapor deposition (PVD), electroless plating, electrolytic plating or brazing, the disclosed devices and methods are not limited to medical devices or electrosurgical devices, but may include a variety of non-conductive devices coated with one or more layers of a variety of conductive materials.

As used herein, the term "distal" refers to the end farthest away from the medical professional when introducing a device into a patient, while the term "proximal" refers to the end closest to the medical professional when introducing a device into a patient.

In various embodiments, the present disclosure relates generally to a medical device (e.g., electrosurgical tip) comprising single or multiple layers of conductive material(s) precisely applied/deposited onto a non-conductive (e.g., ceramic) base in a controlled location and/or pattern and with a low surface area. The layer(s) of conductive material(s) may provide high current density radiofrequency (RF) energy and minimize or prevent collateral thermal damage to surrounding tissues. The components of the medical device local to the layer(s) of conductive material(s) may be electrically and thermally insulative to prevent harm to the patient and/or prevent thermal damage to the medical device itself.

Referring to <FIG>, in one embodiment, a medical device <NUM> (e.g., electrosurgical tip) of the present disclosure may include a non-conductive base component <NUM> comprising a conical or tapered distal portion <NUM> (e.g., an increasing taper or angled surface extending in a constant or varying distal to proximal direction) and a cylindrical proximal portion <NUM> (e.g., with a substantially constant outer dimension). A lumen <NUM> may extend along a longitudinal axis of the non-conductive base component <NUM>. An outer dimension of the cylindrical proximal portion <NUM> may be less than a maximum outer dimension of the tapered distal portion <NUM>. A groove or channel <NUM> may be formed within (e.g., extend along) an outer surface of the non-conductive base component <NUM> along the longitudinal axis of the proximal portion <NUM>. In addition, the channel <NUM> may be formed within (e.g., extend along) a proximal end of the distal portion <NUM> of the non-conductive base component <NUM>. In various embodiments, the non-conductive base component <NUM> may include a variety insulative materials, including, but not limited to ceramic, hard plastics and the like. A ring <NUM> (e.g., circular ring, trace, etc.) of conductive material may be disposed on an outer surface of the non-conductive base component <NUM> around a distal opening <NUM> of the lumen <NUM>. A strip <NUM> (e.g., longitudinal strip, trace, etc.) of conductive material may be disposed on an outer surface of the distal and proximal portions <NUM>, <NUM> along the longitudinal axis of the non-conductive base component <NUM>. A distal end of the strip <NUM> may intersect, overlap or otherwise contact a portion of the ring <NUM> to provide a contiguous layer of conductive material (e.g., a single/unitary conductive layer) on/along the outer surfaces of the distal and proximal portions <NUM>, <NUM> of the non-conductive base component <NUM>. In various embodiments, a portion of the strip <NUM> of conductive material may be disposed within (e.g., extend through) the channel <NUM>.

In one embodiment, the ring <NUM> of conductive material may include a first layer of conductive material bonded to the non-conductive base component <NUM> and the strip <NUM> of conductive material may include a second layer of conductive material bonded to the non-conductive base component <NUM>. The first and second layers of conductive material may be the same or different materials. In various embodiments, the first and second layers of conductive material may include a metal (e.g., titanium) that provides the advantage of forming/creating a strong atomic bond (e.g., adhesion) with the non-conductive base component <NUM> (e.g., ceramic). In various embodiments, the first and/or second layers of conductive material may be applied or deposited to the non-conductive base component <NUM> using physical vapor deposition (e.g., sputter-coating, thermal evaporation, arc spraying, etc.), electroless plating, electrolytic plating or brazing, or other coating applications.

In one embodiment, the ring <NUM> of conductive material may include a third layer of conductive material bonded to the first layer of conductive material, and the strip <NUM> of conductive material may include a fourth layer of conductive material bonded to the second layer of conductive material. The third a fourth layers of conductive material may be the same or different materials (e.g., different from each other and/or different from the first and second layers of material). In various embodiments, the third and fourth layers of conductive material may include a metal (e.g., niobium) that provides the advantage of forming/creating a strong atomic bond (e.g., solderability) with the respective first and second layers of conductive material. In various embodiments, the third and fourth layers of conductive material may be applied or deposited to the non-conductive base component <NUM> using physical vapor deposition (e.g., sputter-coating, thermal evaporation, arc spraying, etc.), electroless plating, electrolytic plating or brazing or other coating applications.

In one embodiment, the ring <NUM> of conductive material may include a fifth layer of conductive material bonded to the third layer of conductive material, and the strip <NUM> of conductive material may include a sixth layer of conductive material bonded to the fourth layer of conductive material. The fifth and sixth layers of conductive material may be the same or different materials (e.g., different from each other and/or different from the first, second, third and fourth layers of material). In various embodiments, the fifth layer of conductive material may include a highly conductive metal (e.g., gold) that forms/creates a strong atomic bond with the third layer of conductive material. In various embodiments, the sixth layer of conductive material may include a conductive metal (e.g., nickel-copper alloy) that form/creates a strong atomic bond with the fourth layer of conductive material and which may form a strong atomic bond with a layer of solder (discussed below). In various embodiments, the fifth and sixth layers of conductive material may be applied or deposited to the non-conductive base component <NUM> using physical vapor deposition (e.g., sputter-coating, thermal evaporation, arc spraying, etc.), electroless plating, electrolytic plating or brazing or other coating applications. In one embodiment, the layers of conductive material comprising the ring <NUM> (e.g., first, third and fifth layers) and the layers of conductive material comprising the strip <NUM> (e.g., second, fourth and sixth layers) may intersect (e.g., overlap, touch, contact, etc.) each other in a variety of different patterns, layers and/or configurations to form a contiguous layer of conductive material (<FIG>). Alternatively, the fifth layer of conductive material may include a compatible filler material <NUM> (e.g., gold, silver, tin, etc.) brazed or welded (<FIG>) to the non-conductive base component (e.g., rather than using physical vapor deposition), and the sixth layer of conductive material may be applied or deposited to the non-conductive base component <NUM> using physical vapor deposition (e.g., sputter-coating, thermal evaporation, arc spraying, etc.), electroless plating, electrolytic plating or brazing or other coating applications. In various embodiments, the brazed or welded layer of conductive material may provide a cutting surface with a geometry designed for a specific application (e.g., a raised, enlarged or thicker cutting surface, etc.).

In various embodiments, the ring <NUM> of conductive material may be the patient contacting portion (e.g., cutting surface) of the medical device <NUM> and the strip <NUM> of conductive material may be the non-patient contacting portion of the medical device. In one embodiment, a distal portion of a conductive wire (not shown) may be disposed within the groove <NUM> and attached to the sixth layer of conductive material by a layer of solder formed within the channel <NUM> on top of (e.g., over) the sixth layer of conductive material and the conductive wire disposed therebetween. A proximal end of the conductive wire may be electrically connected to an electrosurgical generator, as discussed below.

In various embodiments, an inner wall of the lumen <NUM> may not be coated with a conductive material to thermally and electrically insulate the lumen <NUM>, and any medical devices extending therethrough (e.g., cannulas, guidewires, etc.), from the conductive ring <NUM> and/or strip <NUM>. In various embodiments, the low profile/low surface area of the conductive ring <NUM> and strip <NUM> and the surrounding surfaces of the non-conductive base component <NUM> (e.g., distal portion <NUM>, proximal portion <NUM>, lumen <NUM>) may conduct sufficient RF energy to efficiently cut through/penetrate various soft tissue walls (e.g., stomach, duodenum, gallbladder, pancreas, liver, etc.) with minimal collateral thermal damage to the surrounding tissues. The ring <NUM> may be disposed on a distalmost portion of the distal portion <NUM>, such that tissue contacts the ring <NUM> first, and subjected to the RF energy for penetration through the tissue.

In various embodiments, the layer(s) of conductive material(s) may be applied/deposited on the non-conductive base component <NUM> using a line-of-sight PVD process that displaces metal atoms from a cathode using inert plasma atoms. Referring to <FIG>, in one embodiment, a non-conductive base component <NUM> of the present disclosure may be disposed within a fixture <NUM> which masks all outer surfaces of the non-conductive base component <NUM> except for the surfaces to which the ring <NUM> and strip <NUM> are to be applied. A plug or blank <NUM> may be disposed within the distal opening <NUM> of the non-conductive base component <NUM> to shield the lumen <NUM> from contact/coating with the atomized metals. Alternatively, the non-conductive base component <NUM> may be masked with a preformed tape, patternable coating, photoresist or other removable coating to delineate the ring <NUM> and strip <NUM>.

Referring to <FIG>, in one embodiment, the fixture <NUM> may be positioned within a sputter chamber <NUM> such that one side of the fixture <NUM> is directly opposite a metal target 148a (e.g., the conductive material to be sputtered). The sputter chamber <NUM> may serve as an anode, the metal target 148a may serve as a cathode and the inner surface of the sputter chamber <NUM> may serve as an electrode. An inert gas <NUM> (e.g., argon) may be pumped into the sputter chamber <NUM>, energized to a plasma state and an electric field applied to bombard the cathode/metal target 148a. As the plasma atoms contact the metal target 148a, metal atoms may be displaced from the metal target 148a and directed towards the surface of the fixture <NUM>. A thin layer (e.g., approximately <NUM> microns) of sputtered metal 148b may then form on the surface of the fixture <NUM>, including the unmasked/exposed portion of the non-conductive base component <NUM> disposed therein. In various embodiments, the fixture <NUM> may be rotated within the sputter chamber <NUM> to expose the other unmasked surface of the non-conductive base component to the metal target 148a and the process repeated. In addition, the metal target 148a may be replaced with a different metal target to apply/deposit the various layers of metal to the respective portions (e.g., ring <NUM> and strip <NUM>) of the non-conductive base component <NUM>, as discussed above.

Referring to <FIG>, in one embodiment, a system <NUM> of the present disclosure may include a non-conductive base component <NUM> of a medical device <NUM> attached to a distal end of a non-conductive electrosurgical sheath <NUM>. In various embodiments, the proximal portion (not shown) of the non-conductive base component <NUM> may be received/disposed within a distal portion of the electrosurgical sheath <NUM> such that the channel <NUM> (not shown) and distal portion of the conductive wire (not shown) disposed therein are thermally and electrically insulated. The conductive wire may extend along the electrosurgical sheath <NUM> (e.g., embedded within a sidewall of the electrosurgical sheath) to connect a proximal end of the conductive wire to an electrosurgical generator. An access cannula <NUM> may be extendable through the lumen (not shown) of the non-conductive base component <NUM>.

A variety of advantages may be realized by the devices, systems and methods of the present disclosure. For example, the disclosed layer(s) of conductive material(s) applied/deposited onto an outer surface of an electrosurgical device using PVD may allow for broader processing conditions at elevated temperature to provide finer surface features (e.g., lower surface area, lower profile, etc.), thereby reducing production costs, simplifying manufacturing, minimizing collateral thermal damage and maximizing patient safety. The disclosed PVD process may be applied to new medical devices and/or lower the cost of manufacturing or modifying existing medical devices. For example, the manual and expensive process involved in manufacturing a conventional electrosurgical tip, e.g., in which bi-polar traces of gold are printed in a spiral pattern around a non-conductive tip (Gold Probe™ Boston Scientific Corp. , Marlborough MA. ; <FIG>) or a steel wire is formed around a ceramic tip (Hot Axios™ Boston Scientific Corp. , Marlborough MA. ; <FIG>), may be modified to apply/deposit the bipolar or monopolar conductive layers using a PVD process. In various embodiments, for medical applications in which thicker conductive layers may be required, additional layer(s) of conductive material(s) may be applied to the PVD layer using electroless plating, electrolytic plating and/or brazing.

In various embodiments, the order in which the various layers of conductive materials outlined above (e.g., titanium, niobium, gold, nickel-copper alloy) may be applied/deposited to the non-conductive base component may be based on their respective properties of adhesion to the non-conductive base (e.g., ceramic), solderability (e.g., the ability to adhere/bond the highly conductive outer/top layer to the adhesive inner/bottom layer) and/or conductivity (e.g., of the outer/tissue contacting layer). It should be appreciated, however, that the present disclosure is in no way limited to these materials/metals, the number of layers of such materials and/or their order or pattern of deposition. A variety of conductive materials, including, by way of non-limiting example, titanium, niobium, gold, molybdenum, titanium nitride, tantalum, tungsten, platinum, palladium, iridium, tin, nickel, copper, vanadium, silver, zinc or other biocompatible metals, as well as alloys, oxides and nitrides of such materials may be applied/deposited on the disclosed medical device <NUM> in a variety of orders/layers, patterns and/or thicknesses.

In various additional embodiments, the number of layers of conductive material(s) applied to the non-conductive base component (e.g., the ring <NUM> and/or strip <NUM>), is not limited to the first through sixth layers outlined above, but may include a single layer, two layers or any number of additional layers.

In various additional embodiments, the layers of conductive material comprising the ring <NUM> (e.g., first, third and fifth layers) and the layers of conductive material comprising the strip <NUM> (e.g., second, fourth and sixth layers) may intersect (e.g., overlap, touch, contact, etc.) each other in a variety of different patterns, layers and/or configurations to form a contiguous layer of conductive material. For example, a portion of the second layer may partially overlap a portion of the first layer of conductive material, a portion of the third layer of conductive material may partially overlap a portion of the second layer of conductive material, a portion of the fourth layer of conductive material may partially overlap a portion of the third layer of conductive material, a portion of the fifth layer of conductive material may partially overlap a portion of the fourth layer of conductive material and a portion of the sixth layer of conductive material may partially overlap a portion of the fifth layer of conductive material.

Claim 1:
A medical device (<NUM>), comprising:
a non-conductive base component (<NUM>) defining a longitudinal axis and a lumen (<NUM>) therethrough;
a conductive material disposed on an outer surface of the non-conductive base component (<NUM>) around a distal opening (<NUM>) of the lumen (<NUM>); and
wherein the conductive material disposed around the distal opening (<NUM>) includes a first layer of conductive material bonded to the non-conductive base component (<NUM>),
characterized in that
a strip (<NUM>) of conductive material is disposed along the longitudinal axis and includes a second layer of conductive material bonded to the non-conductive base component (<NUM>).