Patent Description:
The present disclosure relates to a medical device. More specifically, the present disclosure relates to a device for retrieving small fragments.

The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.

Lithotripsy is a common method for fragmenting stones, or calculi, in the urinary tract, kidneys, and/or bladder. Lithotripsy, however, can leave stone fragments, which act as nucleation sites for future stone formation, for example, in the lower pole of a kidney. These fragments remain in the patient after the procedure mostly because of the difficulty in capturing very small fragments of dust employing conventional removal devices such as, for example, stone baskets.

Typical corrective actions may include one or more of the following: monitoring for future stone formation, performing additional ureteroscopic procedures, or percutaneous nephrolithotomy. Among the literature that can pertain to this technology include the following patent documents and published patent applications: <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

Accordingly, there is a need for a device that can be employed with lithotripsy that removes small fragments. It would be desirable to have mechanisms which attract, retain, and contain stone fragments to reliably remove small stone fragments and debris.

<CIT> discloses a device which comprises an elongated carrier having a distal portion adapted for positioning inside a body cavity and a proximate portion. A radially expandable polymer is circumferentially attached to the distal portion of the carrier and adapted to enter a matter located inside the body cavity while in a compressed configuration. The expandable polymer is capable of transitioning to an expanded configuration while inside the matter to penetrate and engage it from within.

<CIT> discloses an apparatus for removing an object from a tubular vessel comprising an expandable catheter having a first distal end insertable to a first position adjacent to the object within the tubular vessel, a first opening adjacent to the first distal end, and a first lumen in communication with the first opening.

<CIT> discloses a clot treatment device for intravascular treatment of emboli within a blood vessel of a human patient. The device comprises a support member and a plurality of clot engagement members positioned about the circumference of the support member. The clot engagement members can be generally linear and extend generally parallel to the support member.

<CIT> discloses a medical device for removing concretions from hollow body organs with a catheter comprising a suction line and at least one suction element.

The present disclosure provides an improved small fragment retrieval device. The invention is disclosed by independent claim <NUM>, with further embodiments disclosed in the dependent claims.

In one aspect, the present disclosure provides a medical device for retrieving small fragments from within a patient's anatomy. The medical device includes a collection wire configured for entering a patient's anatomy. The collection wire includes a distalmost end with a plurality of tips. The plurality of tips comprises a plurality of filaments that are intertwined into a fibrous structure. The plurality of tips is that are configured to attract stone fragments from the patient's anatomy and comprises at least one of: i) a magnetic outer surface; or ii) a nanofunctional molecule bonded to an outer surface.

The medical device may be further characterized by one or any combination of the features described herein, such as, for example: the plurality of tips are a plurality of curled tips; the tips of the plurality of tips extend laterally from the distal end, the tips of the plurality of tips being spaced apart and positioned about the distal end in a spiral arrangement; the medical device further comprises a wire mesh that selectively surrounds the plurality of tips; the wire mesh selectively surrounds the plurality of tips by moving distally and proximally relative to the plurality of tips; the wire mesh is configured to collapse over the plurality of tips; the collection wire is formed of molded silicone; the collection wire is formed of molded plastic; the plurality of tips include a magnetic outer surface; the plurality of tips include a calcium attractive outer surface.

Further features, advantages, and areas of applicability will become apparent from the description provided herein.

Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings:.

Referring now to the drawings, a small fragment retrieval device or collection wire embodying the principles of the present invention is illustrated in <FIG> and designated at <NUM>. The collection wire <NUM> includes a shaft <NUM> with a proximal end <NUM> and a distal end <NUM>. A plurality of tips <NUM> is attached to the distal end <NUM> of the shaft <NUM>. In the configuration shown in <FIG>, the plurality of tips <NUM> is a plurality of filaments that are intertwined into a fibrous structure <NUM>. The fibrous structure <NUM> is porous to allow fluid to flow through it while capturing small stone fragments and dust particles that are generated during lithotripsy.

When in use, a physician inserts the collection wire <NUM> into a patient's anatomy so that the fibrous structure <NUM> is positioned near an anatomical region of the patient that contains small stone fragments and dust which may have been produced, for example, by lithotripsy. As the physician sweeps the fibrous structure <NUM> around the anatomical region, the small stone fragments and dust are collected by the filaments <NUM>. After the stone fragments and dust have been accumulated into a conglomeration of stone fragments <NUM>, the physician pulls on the shaft <NUM> to retrieve the collection wire <NUM> along with the conglomeration of stone fragments <NUM> from the patient's anatomy.

It is contemplated that the fibrous structure may include synthetic balls of material comprising rayon or polyester, ultra-high-molecularweight polyethylene (UHMWPE), other polymers, or the like. It is further contemplated that individual filaments of the fibrous structure may be coated with a flexible polymer or adhesive, such as for example amyloid fiber, natural amyloid fiber, mussel foot proteins (Mfps), or bundles of carbon nanotubes to make use of microscale van der Waals forces to capture the small stone
fragments or dust (that is, "gecko tape").

Referring further to <FIG>, the collection wire <NUM> may include an optional containment device <NUM>. The containment device <NUM> includes a sheath <NUM> and an expandable cone-shaped basket <NUM> attached to a distal end <NUM> of the sheath <NUM>. The cone-shape basket <NUM> may be made from a solid material or from a mesh.

When in use, the sheath <NUM> and the basket <NUM> are initially placed over the shaft <NUM> of the collection wire <NUM> such that basket <NUM> is collapsed about the shaft <NUM>. After the conglomeration of stone fragments <NUM> is collected by the filaments <NUM> as described above, the physician pulls the proximal end <NUM> of the shaft <NUM> relative to the containment device <NUM>. As this occurs, the basket expands or opens as the conglomeration of stone fragments <NUM> is pulled into the basket <NUM>. The physician then removes the collection wire <NUM> along with the conglomeration of stone fragments <NUM> contained in the basket <NUM> from the patient's anatomy.

Turning now to <FIG>, there is shown an alternative small fragment retrieval device or collection wire <NUM> that includes a shaft <NUM> with a proximal end <NUM> and a distal end <NUM>. A plurality of tips <NUM> is attached to the distal end <NUM> of the shaft <NUM>. The plurality of tips <NUM> includes a plurality of primary curled tips <NUM> and a plurality of secondary curled tips <NUM> attached to the primary curled tips <NUM>. The collection wire <NUM> may include a containment device <NUM> that includes a sheath <NUM> and an expandable basket <NUM> attached to a distal end <NUM> of the sheath <NUM>. The basket <NUM> may be formed from a solid material or may have a mesh structure.

When in use, the sheath <NUM> and the basket <NUM> are initially placed over the shaft <NUM> such that the basket <NUM> is collapsed about the shaft <NUM>. The collection wire <NUM> is inserted into a patient's anatomy so that the plurality of tips <NUM> is positioned near an anatomical region of the patient that contains small stone fragments and dust. As a physician sweeps the plurality of tips <NUM> around the anatomical region, the small stone fragments and dust are collected by the primary and secondary curled tips <NUM> and <NUM>. After the stone fragments and dust have been accumulated into the conglomeration of stone fragments <NUM>, the physician pulls on the proximal end <NUM> of the shaft <NUM> so that the conglomeration of stone fragments is pulled into the basket <NUM> as the basket <NUM> expands to an open state. The physician then retrieves the collection wire <NUM> along with the conglomeration of stone fragments <NUM> contained in the basket <NUM> from the patient's anatomy. In certain procedures, the collection wire <NUM> can be employed without the use of the containment device <NUM>.

The plurality of tips <NUM> and <NUM> described above are generally flexible and are made of any suitable material such as, for example, plastic, silicone or metal. The filaments <NUM> of the collection wire <NUM> and the primary and secondary curled tips <NUM> and <NUM> of the collection wire <NUM> can be coated with an adhesive material. For example, the adhesive may be a calcium attractant adhesive. It is contemplated that the filaments, collection wire, and/or curled tips may be coated (for example, sinter bonded) with calcium oxalate or an alternative calcium-based mineral. Subsequently, a nanofunctional molecule, which may be a protein or a polyanionic macromolecule and which may be provided with a calcium attractive surface at both ends, is applied to the filaments, collection wire, and/or curled tips so as to attract stone dust or stone debris containing calcium oxalate. The nanofunctional molecule could be carboxylic acid-rich proteins, osteopontin, or prothrombin fragment <NUM>, for example, or the like, and may be crosslinked with a second nanofunctional molecule. In this way, the nanofunctional molecule may be calcium attractive at two opposing ends and thereby attract and retain stone dust and debris to the filaments, curled tips, and/or collection wire. It is further contemplated that the nanofunctional molecule may be long enough such that multiple calcium
attractive sites are provided on a single molecule. In this case, the nanofunctional molecule would be sufficient to attract and retain stone dust and debris to the filaments, curled tips, and/or collection wire.

Alternatively, the filaments <NUM> and the primary and secondary curled tips <NUM> and <NUM> may be coated with magnetic material to act as a magnetic attractant. It is contemplated that contacting kidney stones with ferrous or magnetic particles that are able to bind the kidney stone debris, and reacting the kidney stone debris with the ferrous or magnetic particles may cause the kidney stone debris to become attractable magnetically. In one aspect, the ferrous or magnetic particles may further comprise an agent that specifically binds the surface of the kidney stone debris selected from proteins that interact with calcium-based biominerals, such as carboxylic acid-rich proteins, osteopontin, prothrombin fragment <NUM>. It is contemplated that the magnetic protein ferritin may be used as a second protein and cross-linked to one of the nanofunctional proteins, or first proteins, mentioned above and used for this purpose.

Referring now to <FIG>, there is shown yet another small fragment retrieval device or collection wire <NUM>. The collection wire <NUM> includes a shaft <NUM> and a plurality of tips <NUM>. The plurality of tips <NUM> may be formed integrally with a distal portion of the shaft <NUM>, or the plurality of tips <NUM> may include a primary projection <NUM> attached the distal end <NUM> of the shaft <NUM>. The plurality of tips <NUM> further includes a collection of projections <NUM> that extend substantially laterally from the distal portion of the shaft <NUM> or from the primary projection <NUM>. As illustrated in <FIG>, the projections <NUM> are spaced apart and are arranged in a spiral pattern or arrangement about the primary projection <NUM>. The plurality of tips can be coated with an adhesive, such as, for example, calcium attractant adhesive or a magnetic attractant.

The collection wire <NUM> also includes a containment device <NUM>. The containment device <NUM> includes a sheath <NUM> and a basket <NUM> attached to a distal end <NUM> of the sheath <NUM>. The basket <NUM> may be made of a solid material or a mesh-like structure with a plurality of holes <NUM>.

When in use, the sheath <NUM> and the basket <NUM> are placed over the shaft <NUM>. A physician inserts the retrieval device <NUM> into a patient's anatomy so that the plurality of tips <NUM> is positioned near an anatomical region of the patient that contains small stone fragments and dust. As the physician sweeps the plurality of tips <NUM> around the anatomical region, the small stone fragments and dust are collected by the collection of projections <NUM>. After the stone fragments have been accumulated into a conglomeration of stone fragments, the physician pulls on the proximal end of the shaft <NUM> so that the conglomeration of stone fragments and dust are pulled into a distal end <NUM> of the basket <NUM>. The physician then retrieves the collection wire <NUM> along with the conglomeration of stone fragments and dust contained in the basket <NUM> from the patient's anatomy. In certain procedures, the collection wire <NUM> can be employed without the use of the containment device <NUM>.

It is contemplated that various substances and methods may be used to produce a flocculation or aggregation of stone dust or debris particulates prior to the various collection methods described herein being commenced. For example, flocculation may be accomplished through the creation of a low pH environment in the kidney. It is further contemplated that adding, ejecting, and/or inserting an adhesive agent such as polyethylenimine, biocompatible nanoadhesive such as alginate gel, cellulose gel, protein based gel, collagen, polysaccharide, chitosan gel, in vivo gel formulations which at least in part polymerize and/or gel at the target site in a human body to form a biocompatible hydrogel polymer, ferrogels, and/or biocompatible magnetic gels which may include polyvinyl alcohol and gluteraldehyde may help to aggregate stone dust or stone debris. It is contemplated that such an adhesive agent may be added, injected, and/or inserted with an additional device such as a catheter or out of an opening in a distal most end of the primary projection <NUM>, for example. The adhesive agent may be given some time to collect stone dust or stone debris, the primary projection <NUM> or other collection device may be inserted into the region containing the adhesive agent to attract the adhesive agent containing stone dust and stone debris, the containment device <NUM> may surround the primary projection <NUM> or other collection device, and the device may be subsequently removed from a patient.

In some arrangements, the plurality of tips <NUM>, such as, for example, the primary projection <NUM> and the collection of projections <NUM>, may be coated with a calcium attractant adhesive, similar to the coating described previously with respect to filaments <NUM> of the collection wire <NUM> and the primary and secondary curled tips <NUM> and <NUM> of the collection wire <NUM>. For example, the plurality of tips <NUM> may be coated (for example, sinter bonded) with calcium oxalate or an alternative calcium-based mineral <NUM>, as shown in <FIG>. Subsequently, a nanofunctional molecule <NUM>, which may be a protein or a polyanionic macromolecule and which may be provided with a calcium attractive surface at both ends, is applied to the plurality of tips <NUM> so as to attract stone dust or stone debris <NUM> containing calcium oxalate. The nanofunctional molecule <NUM> could be carboxylic acid-rich proteins, osteopontin, or prothrombin fragment <NUM>, for example, or the like, and may be crosslinked with a second nanofunctional molecule. In this way, the nanofunctional molecule <NUM> may be calcium attractive at two opposing ends and thereby attract and retain stone dust and debris to the plurality of tips <NUM>. It is further contemplated that the nanofunctional molecule <NUM> may be long enough such that multiple calcium attractive sites are provided on a single molecule. In this case, the nanofunctional molecule would be sufficient to attract and retain stone dust and debris <NUM> to the plurality of tips <NUM>.

Claim 1:
A medical device comprising:
a collection wire (<NUM>) configured for entering a patient's anatomy, the collection wire including a distalmost end with a plurality of tips (<NUM>), the plurality of tips comprising a plurality of filaments intertwined into a fibrous structure (<NUM>), wherein the plurality of tips are configured to attract stone fragments from the patient's anatomy and comprise at least one of:
i) a magnetic outer surface; or
ii) a nanofunctional molecule bonded to an outer surface.