Patent Description:
A stereotactic biopsy procedure is performed by inserting a biopsy probe, e.g., needle, into a patient to form a tract to the biopsy site, where the biopsy probe collects one or more biopsy samples and forms a cavity as a result of tissue removal. Such a biopsy procedure typically results in significant bleeding at the tract, which may include the biopsy cavity, well after the biopsy has been completed. Also, after most biopsies, a tissue marker is deployed at the biopsy site to mark the location of the biopsy site. The tissue marker is configured to be visible under one or more imaging modalities, such as for example, ultrasound, MRI and X-ray.

What is needed in the art is a hemostatic biopsy tract article that may serve as a hemostatic tract plug, and which optionally may carry a tissue marker so as to both mark the biopsy site and effectively control bleeding at the biopsy site.

<CIT> discloses a method of making the closure device and a system that includes the closure device for closing an opening in a body lumen. Further, <CIT> relates to tissue closure devices achieving tissue closure in lieu of compression and can be configured to be quickly deployable by an introducer or from outside the body. Further, <CIT> discloses a marking device containing a bioabsorbable or non-bioabsorbable marker, which falls under subject-matter as defined in the preamble of claim <NUM>.

The present invention provides a hemostatic biopsy tract article according to claim <NUM>, which, in particular, may serve as a hemostatic tract plug, and which optionally may carry a tissue marker so as to both mark the biopsy site and effectively control bleeding at the biopsy site.

The disclosure in one form is directed to a hemostatic biopsy tract article. The hemostatic biopsy tract article includes a bioresorbable body having a microporous structure. The bioresorbable body is formed by a mixture that includes a bioabsorbable hemostatic powder, a hydrolyzed starch, hyaluronic acid, and carboxymethylcellulose. Optionally, a marker element may be coupled to the bioresorbable body, wherein the marker element is formed from a material that is imageable under at least one imaging modality.

One advantage of the invention is that the bioresorbable body instantly dehydrates and gels blood upon contact with blood by the effect of its hydrophilic materials and microporous structure.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

Referring now to the drawings, and more particularly to <FIG>, there is shown a hemostatic biopsy tract article <NUM> in accordance with the present invention.

Referring also to <FIG>, hemostatic biopsy tract article <NUM> is designed to be carried by, and expelled from, an introducer device <NUM>. In the present embodiment, hemostatic biopsy tract article <NUM> has an elongate cylindrical shape, although it is contemplated that other shapes may be selected, for example, based on the application for which hemostatic biopsy tract article <NUM> is to be used. Introducer device <NUM> includes a handle body <NUM>, a plunger <NUM>, and a cannula <NUM>. In the present embodiment, handle body <NUM> is molded to cannula <NUM>.

Referring also to <FIG>, cannula <NUM> includes a distal end <NUM>-<NUM> and a lumen <NUM>-<NUM>. Lumen <NUM>-<NUM> distally terminates at distal end <NUM>-<NUM> to define a delivery port <NUM>-<NUM> associated with lumen <NUM>-<NUM>. Plunger <NUM> includes a plunger head <NUM>-<NUM> and a plunger shaft <NUM>-<NUM> that extends from plunger head <NUM>-<NUM>. A distal portion <NUM>-<NUM> of plunger shaft <NUM>-<NUM> of plunger <NUM> is slidably received in lumen <NUM>-<NUM> of cannula <NUM>. Hemostatic biopsy tract article <NUM> is positioned in lumen <NUM>-<NUM> of cannula <NUM> distal to distal portion <NUM>-<NUM> of plunger <NUM>.

By depressing plunger head <NUM>-<NUM> in a distal direction <NUM>, plunger shaft <NUM>-<NUM> moves in distal direction <NUM> so as to expel hemostatic biopsy tract article <NUM> from delivery port <NUM>-<NUM> of cannula <NUM>.

Those skilled in the art will recognize that the distal end <NUM>-<NUM> of cannula <NUM> may have a configuration other than the beveled tip configuration as shown. For example, it is contemplated that distal end <NUM>-<NUM> may be blunt, rounded, symmetrically pointed, asymmetrically pointed, etc. Also, as an alternative to delivery port <NUM>-<NUM> being located at distal end <NUM>-<NUM> of cannula <NUM>, it is contemplated that delivery port <NUM>-<NUM> may be formed in the side wall of cannula <NUM> to facilitate a side delivery of hemostatic biopsy tract article <NUM> from cannula <NUM>.

Hemostatic biopsy tract article <NUM> is configured such that bioresorbable body <NUM>-<NUM> is bioresorbable, hemostatic, and has a microporous structure. In the present embodiment, bioresorbable body <NUM>-<NUM> is formed by a mixture, e.g., a solution, which includes a bioabsorbable hemostatic powder, a hydrolyzed starch, hyaluronic acid, and carboxymethylcellulose. Each of the bioabsorbable hemostatic powder, the hydrolyzed starch, the hyaluronic acid, and the carboxymethylcellulose is a hydrophilic material, and thus, in the present embodiment, bioresorbable body <NUM>-<NUM> is formed using four different hydrophilic materials.

The bioabsorbable hemostatic powder is a plant-based starch powder of a different starch material from that of the hydrolyzed starch. The bioabsorbable hemostatic powder may be, for example, an unhydrolyzed starch. In one form, the bioabsorbable hemostatic powder is commercially available under the tradename, Arista(™), from C. (See, e.g., <CIT>). The Arista brand starch is an unhydrolyzed starch (plant-based) that comprises of large number of glucose units. In contrast to the Arista brand starch, the hydrolyzed starch contains shorter glucose units (e.g. monosaccharides, disaccharides or trisaccharides).

Hydrolyzed starch consists of smaller saccharides molecules than an initial starch. Starch is a polymeric carbohydrate consisting of a large number of glucose units joined by glycoside bonds. Whenever starch (polysaccharides) molecules undergo hydrolysis, it forms either monosaccharides, disaccharides or trisaccharides.

Hyaluronic acid is an anionic, nonsulfated glycosaminoglycan, which are long unbranched polysaccharides consisting of a repeating disaccharide unit.

Carboxymethylcellulose (CMC) is a cellulose derivative with carboxymethyl groups bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone.

Where the mixture is a solution containing water, e.g., distilled water, the mixture is lyophilized or compressed to remove the water and form bioresorbable body <NUM>-<NUM>. In the present embodiment, no other ingredients are added in this solution. However, it is contemplated that drugs or growth factors can be incorporated in the solution to generate foam that can deliver bioactive components, if desired.

In one example, to achieve the microporous structure having hemostatic and bioresorbable characteristics of the present invention, a ratio of hyaluronic acid to carboxymethylcellulose is in a range of <NUM>:<NUM> to <NUM>:<NUM>, and a ratio of the bioabsorbable hemostatic powder to the hydrolyzed starch is in a range of <NUM>:<NUM> to <NUM>:<NUM>. It has been observed that a pore size of bioresorbable body <NUM>-<NUM> may be increased by increasing the ratio of hyaluronic acid to carboxymethylcellulose. Conversely, a pore size of the bioresorbable body <NUM>-<NUM> may be decreased by decreasing the ratio of hyaluronic acid to carboxymethylcellulose.

In one embodiment, hemostatic biopsy tract article <NUM> is formed from a solution that includes the bioabsorbable hemostatic powder (<NUM>% to <NUM> % by weight/volume), the hydrolyzed starch (<NUM>% to <NUM> % by weight/volume), the hyaluronic acid (<NUM>% to <NUM> % by weight/volume), and the carboxymethylcellulose (<NUM>% to <NUM> % by weight/volume). The estimated overall pore size range is from <NUM> nanometers to as large as <NUM> microns.

EXAMPLE: In the present example, a bioresorbable body having a microporous structure in accordance with the present invention is formed by making a solution that is formed by dissolving in distilled water: bioabsorbable hemostatic powder, e.g. Arista brand starch powder, (<NUM>% by weight/volume), hydrolyzed starch (<NUM>% by weight/volume), hyaluronic acid (<NUM>% by weight/volume), and carboxymethylcellulose (<NUM>% by weight/volume). The solution is mixed for <NUM> minutes or until all particles are dissolved, and is then poured into an open-top container which is then placed onto a pre-cooled shelf, and the microporous foam is formed by removing water by a sublimation process or freeze drying process (e.g., the entire process takes about <NUM> hours). The pore size of the microporous foam of this example is in a range of <NUM> nanometers to about <NUM> microns.

Advantageously, bioresorbable body <NUM>-<NUM> of hemostatic biopsy tract article <NUM> instantly dehydrates and gels blood upon contact with blood by the effect of the hydrophilic materials and microporous structure. Also, hemostatic biopsy tract article <NUM> is completely resorbed over a period of time, with the bioabsorbable hemostatic powder being resorbed within <NUM> to <NUM> hours of amylases. Again, the bioabsorbable hemostatic powder is a plant-based starch powder of a different starch material from that of the hydrolyzed starch.

It is contemplated that bioresorbable body <NUM>-<NUM> of hemostatic biopsy tract article <NUM> may be placed into any biopsy tract to achieve hemostasis following a biopsy. Such biopsies may include, for example, a breast biopsy or an organ biopsy, such as for example, a liver or renal biopsy. Further, it is contemplated that lung biopsies may also be embolized with bioresorbable body <NUM>-<NUM> of hemostatic biopsy tract article <NUM> to form a blood clot at the pleural surfaces and prevent a pneumothorax and promote tissue re-modeling of the lung parenchyma once a blood clot is formed.

Referring to the embodiments of <FIG>, hemostatic biopsy tract article <NUM> may be adapted to include a tissue marker formed from a material that is imageable under at least one imaging modality, e.g., x-ray, MRI, or ultrasound.

For example, as depicted in <FIG>, hemostatic biopsy tract article <NUM> may be adapted to include a marker element <NUM> that is coupled to bioresorbable body <NUM>-<NUM>. Marker element <NUM> is formed from a material that is imageable under at least one imaging modality, e.g., x-ray, MRI, or ultrasound. For example, where the desired imaging modality is x-ray or MRI, marker element <NUM> may be formed from stainless steel or titanium. Where the desired imaging modality is ultrasound, marker element <NUM> may be formed to include reflective surfaces. In the present embodiment depicted in <FIG>, marker element <NUM> is an exterior band attached to an exterior of bioresorbable body <NUM>-<NUM>.

In the example depicted in <FIG>, hemostatic biopsy tract article <NUM> may be adapted to contain a marker element <NUM>, which in turn is coupled to bioresorbable body <NUM>-<NUM> by being contained within bioresorbable body <NUM>-<NUM>. Marker element <NUM> is formed from a material that is imageable under at least one imaging modality, e.g., x-ray, MRI, or ultrasound. For example, where the desired imaging modality is x-ray or MRI, marker element <NUM> may be formed from stainless steel or titanium. Where the desired imaging modality is ultrasound, marker element <NUM> may be formed to include reflective surfaces. In the present embodiment depicted in <FIG>, marker element <NUM> has a ribbon shape, but it is to be recognized that other shapes of marker element <NUM>, e.g., ring, flat, coil, loop, hook, polygonal, spherical, elliptical, star, ribbon, a combination, etc., may be utilized based on the medical application or user preference.

While in the embodiments set forth above, bioresorbable body <NUM>-<NUM> of hemostatic biopsy tract article <NUM> is depicted as having an elongate cylindrical shape, it is contemplated that other shapes may be selected, for example, based on the application for which hemostatic biopsy tract article <NUM> is to be used. For example, it is contemplated that bioresorbable body <NUM>-<NUM> of hemostatic biopsy tract article <NUM> could also be a rolled flat sheet, or multiple flat sheets, and may include a radiopaque or other imageable marker element embedded in the sheet or between sheets.

<FIG> shows an embodiment of a hemostatic biopsy tract article <NUM>, in accordance with another embodiment of the invention. Hemostatic biopsy tract article <NUM> may be used to mark a biopsy cavity and/or tract, such as for example, a breast biopsy cavity where tissue samples have been removed.

Hemostatic biopsy tract article <NUM> includes a bioresorbable body <NUM>, a bioresorbable sleeve <NUM>, a void <NUM>, and a marker element <NUM>. In the present embodiment, hemostatic biopsy tract article <NUM> has an elongate cylindrical shape, and also may be carried and delivered by an introducer device, such as introducer device <NUM> shown in <FIG>.

Bioresorbable body <NUM> includes a first body segment <NUM>-<NUM> and a second body segment <NUM>-<NUM>. First body segment <NUM>-<NUM> and a second body segment <NUM>-<NUM> are arranged along a longitudinal axis <NUM>. First body segment <NUM>-<NUM> is spaced a distance <NUM> from second body segment <NUM>-<NUM> along longitudinal axis <NUM> to form the void <NUM> between first body segment <NUM>-<NUM> and second body segment <NUM>-<NUM>. Marker element <NUM> is positioned in void <NUM> between first body segment <NUM>-<NUM> and second body segment <NUM>-<NUM>. Bioresorbable sleeve <NUM> encapsulates void <NUM> to contain marker element <NUM>, and bioresorbable sleeve <NUM> connects, e.g., by a friction fit or biocompatible adhesive, to each of first body segment <NUM>-<NUM> and second body segment <NUM>-<NUM>.

Bioresorbable body <NUM> has the same chemical composition as that of bioresorbable body <NUM>-<NUM> described above. Accordingly, each of first body segment <NUM>-<NUM> and a second body segment <NUM>-<NUM> also has the same chemical composition as that of bioresorbable body <NUM>-<NUM> described above. First body segment <NUM>-<NUM> and a second body segment <NUM>-<NUM> may be formed individually, or separated from the same base bioresorbable body, such as for example, by dividing bioresorbable body <NUM>-<NUM> into two body segments.

Bioresorbable sleeve <NUM> may have the same chemical composition as that of bioresorbable body <NUM>-<NUM>, described above, or alternatively, may be a tube formed from another type of bioresorbable material.

Void <NUM> may be an air space, or alternatively, may be filled with a biocompatible fluid, such as saline or an MRI contrast agent.

Marker element <NUM> is formed from a material that is imageable under at least one imaging modality, e.g., x-ray, MRI, or ultrasound. Marker element <NUM> is shown schematically as a rectangle, but may be any suitable shape as determined or desired for a particular purpose. For example, the shape of marker element <NUM> may be a ring, flat, coil, loop, hook, polygonal, spherical, elliptical, star, ribbon, a combination, etc. Where the desired imaging modality is x-ray or MRI, marker element <NUM> may be formed from stainless steel or titanium. Where the desired imaging modality is ultrasound, marker element <NUM> may be formed to include reflective surfaces. It is noted that void <NUM> may itself provide ultrasound and MRI contrast. Also, it is contemplated that marker element <NUM> may itself be a plurality of individual marker elements.

As used herein, the terms "connected" or "attached" mean a direct or indirect affixation of one component to another component. The term "about", and other words of degree, are relative modifiers intended to indicate permissible variation from the characteristic so modified.

Claim 1:
A hemostatic biopsy tract article (<NUM>), comprising a bioresorbable body (<NUM>-<NUM>) characterised in that the bioresorbable body has a microporous structure, and in that the bioresorbable body is formed by a mixture that includes a bioabsorbable hemostatic powder, a hydrolyzed starch, hyaluronic acid, and carboxymethylcellulose.