Patent ID: 12193956

DETAILED DESCRIPTION

The example embodiments described herein are directed to urological stents and applicators and, more particularly to prostatic chitosan urological stents and associated applicators configured to be inserted into the urethra of a patient. In the example embodiments described, a combined stent and applicator has a catheter function, with the stent and the applicator being connected in series. This allows an inner lumen of the stent to remain sufficiently open to provide for both irrigation and drainage of an irrigation solution. In doing so, the need to insert a multi-lumen tube into the inner lumen of the stent is avoided. The applicator can be maintained in place with the prostatic chitosan stent to allow for irrigation of the bladder and drainage of the solution back through the applicator, thereby flushing the bladder.

FIG.1is a diagram illustrating some features of male human anatomy. In particular, a bladder is shown along with various elements of the male urological system. The urethra extends from the bladder through the prostate and allows urine to pass. The locations of the urethral sphincter, which is a set of muscles that controls the flow of urine, the verumontanum, and the bladder neck are also shown.

Referring toFIGS.2and3, one example of a prostatic chitosan stent is shown generally at10and is hereinafter referred to as “stent10.” In this example, the stent10comprises a first member12(braid) forming a first layer and a second member14(sponge layer) forming a second layer with the first member12retained in the second member14. The second member14is either formed on the first member12or attached to the first member to form the stent as a unitary structure for insertion into the patient's urethra.

The first member12has a general tubular shape forming an inner lumen16between a proximal end18and a distal end20. The first member12or braid, in this example, has a scaffold structure formed as a lattice or grille and comprises at least one bioresorbable material. In this example, the distal end20of the first member12has the lattice or grille forming an open tip22and extending outward from a distal end26of the second member14. As shown inFIG.3, the proximal end18of the first member12is also open and extends beyond the proximal end of the second member14.

The second member14forms the layer around at least a portion of the scaffold structure of the first member12. The second member14also comprises at least one bioresorbable material which may be at least partially the same as the bioresorbable material(s) of the first member12.

The second member14has a substantially uniform outer diameter in the non-expanded configuration as shown by diameter C inFIG.3, but expands into a non-uniform outer diameter as shown inFIGS.2and3as the second member14expands, such as by hydroscopic expanding or swelling for example, and/or by means of removing a compression covering. In this example, the non-uniform exterior shape of the second member14in its expanded configuration includes a distal section38, a proximal section42, and a middle section40. The distal section38provides an enlarged section which is configured to be located inside the bladder and function as a bladder neck cover to seat against the bladder neck of the patient. This can help the user to position the stent10and prevent the stent10from moving away from the bladder neck, at least until dissolved. The middle section40can have a general conical shape extending down to the narrower diameter proximal section42. The middle section40and the proximal section42can form the active length in the bladder. In one type of example, the shape of the middle section40and the proximal section42may be designed based upon clinical observations of the general shape of the area inside the prostate and usually formed by resection to thereby fit or fill the area efficiently. In this example, the second member14is formed as a chitosan sponge-type outer layer on the braid. A sponge-type outer layer allows for compression during a production process for easier insertion into the urethra of the patient.

Referring toFIGS.4-8, one example of the prostatic chitosan stent10and a method of placing the stent10using an applicator50is shown. The generally tubular shape of the scaffold structure of the first member12is configured to provide structural strength and sufficient radial force to hold the urethra open and allow passage of urine through the inner lumen16. The scaffold structure may be provided initially in a radially collapsed configuration about the longitudinal axis of the inner lumen16, at least partially, which is subsequently allowed to expand or deploy, such as by self-expandable resilient deflection, into an expanded configuration.

The stent10is serially located on a distal end of the applicator50. The second member14is compressed and protected by the compression covering, which is a retractable protective film layer or cover and is hereinafter referred to as a sheath72, which, as described below, is comprised of three layers. The stent10includes a balloon60that, in a non-expanded state (FIG.4), is positioned in the distal end of the stent10within the first member12. After the stent10is suitably located and at least a portion of the sheath72is removed, the balloon60may be expanded as shown inFIG.5to help position and hold the stent10relative to the prostate.

Referring now toFIGS.6and7, because the first member12is longer than the second member14on both ends, both the proximal end18and the distal end20of the first member12(or braid) deform into funnel shapes when the first member12expands. The funnel shape at the distal end20allows the stent10to anchor between the verumontanum and the external urethral sphincter.

Still referring toFIGS.6and7, the stent10is allowed to expand inside the patient. This expansion may be merely resilient expansion and/or hydroscopic expansion of the material of the second member14of the stent10. If the expansion of the second member14is hydroscopic, such expansion may be due to contact with urine or other fluids.

As shown inFIG.7, the balloon60may be collapsed and retracted. Upon retraction of the balloon60and the applicator50from the proximal end18of the stent10, the stent10remains deployed in the patient as shown inFIG.8.

Referring now toFIGS.9A and9B, an applicator/stent system is shown generally at70and is hereinafter referred to as “system70.” The system70comprises the applicator50having a main body52defined by a multi-lumen tube having a drain lumen74(first lumen) and an irrigation lumen75(second lumen), similar to that of a 2-way catheter, with the irrigation lumen75extending as the branched portion of the main body52. The balloon60is operably coupled to a tube62and is expanded and retracted through the drain lumen74using the tube62. The multi-lumen tube may also include a third lumen for additional functions. In any embodiment, the applicator50is serially coupled to the stent10defined by the first member12and the second member14. As shown inFIG.9A, the balloon60in non-expanded state is positioned at the distal end of and within the first member12.

When the applicator50is serially coupled to the stent10to form the system70, the sheath (shown at72) having the three layers is located over a distal portion of the main body52and the stent10. A first layer80(inner layer) of the sheath72covers the proximal end of the first member12and a portion of the main body52of the applicator50and couples the stent10to the main body52to maintain the catheter-like function of the system70. In maintaining the catheter-like function, irrigation fluid may be delivered and drained through the applicator50.

A second layer82(middle layer) of the sheath72covers from the distal end26of the second member14to the main body52to protect the second member14from contact with fluid.

A third layer84(outer layer) of the sheath10covers from the distal end of the stent10(with the balloon60therein) to the main body52. The entire stent10assembled with the unexpanded balloon60is covered by the third layer84. This third layer84may be stretchable to compress the applicator assembly to maintain the assembled stent10, balloon60, and applicator50sufficiently thin for insertion into a patient's urethra and to restrict the expansion of the stent10.

After insertion of the assembled stent10, balloon60, and applicator50into the urethra of a patient, the third layer84(outer layer) is removed to expose the distal portion of the stent10with the balloon60therein. In doing so, the distal end20of the first member12and the balloon60are no longer restricted from being opened. As shown inFIG.9B, the balloon60may be expanded, thus expanding the distal end20of the first member12, to facilitate the positioning of the stent10. Once the stent10is positioned, the second layer82(middle layer) is subsequently removed, thereby exposing the second member14to urine to allow the second member14to expand (in the case of hydroscopic expansion of the material of the second member14). A suitable period of time (for example, about three minutes) is allowed to pass to ensure that the stent10is fully expanded. The balloon60may then be collapsed and retracted through the applicator50. Once the balloon60is clear of the drain lumen74, irrigation fluid may be delivered through the irrigation lumen75to the bladder.

Referring now toFIGS.10A-10H, the steps of one example method of using the prostatic chitosan stent10are shown. As shown inFIG.10A, the stent10with the multi-lumen applicator50may be inserted into the urethra of a patient and into the prostate P. As can be seen, the stent10and the applicator50are serially arranged with the sheath72over the stent10such that the third layer84covers the second member14as well as the extended portion of the first member12. As shown inFIG.10B, the third layer84of the sheath72is removed such that the distal end of the first member12can be opened. As shown, the lattice or grille structure at the extended portion of the first member12is splayed. The second layer82remains on the second member14. As shown inFIG.10C, the balloon60is expanded, for example, via the injection of sterile water or by being inflated with a gas such as air or any inert gas. This expansion of the balloon60also expands the extended portion of the first member12to form the funnel. As shown inFIG.10D, upon removal of the second layer82of the sheath72, the second member14absorbs urine, and the chitosan material begins to expand. As shown inFIG.10E, the second member14is expanded, and the stent10is maintained in place for a period of time (for example, three minutes) to allow for the full expansion of the second member14. As shown inFIG.10F, the balloon60is deflated, for example, by the suction of the sterile water from the balloon60. As shown inFIG.10G, the balloon60is extracted. Irrigation fluid may be provided through the second lumen of the multi-lumen tube. Drainage of the irrigation fluid (as well as other fluid from the bladder) may be through the first lumen. In general, the patient may be maintained catheterized in a recovery room. As shown inFIG.10Hthe multi-lumen tube defining the applicator50is separated from the stent10and retracted. Retraction of the applicator50will generally be conditioned on an analysis of the drained urine and/or solution. The first layer80of the sheath72may be removed to allow the proximal end of the first member12to expand into the funnel shape, shown at90. If the applicator50is retracted, the patient may be allowed to leave the place of treatment without any tubes and with only the bioresorbable stent10in the urethra.

In any example described herein, the first member12is comprised of at least one bioresorbable material such as, for example, poly(L-lactide) or poly(D,L-lactide), and the second member14is comprised of chistosan, which is used to support the healing of treated mucosa. Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit).

Below are provided further descriptions of various non-limiting, exemplary embodiments. The below-described exemplary embodiments may be practiced in conjunction with one or more other aspects or exemplary embodiments. That is, the exemplary embodiments of the invention, such as those described below, may be implemented, practiced, or utilized in any combination (for example, any combination that is suitable, practicable, and/or feasible) and are not limited only to those combinations described herein and/or included in the appended claims.

In one exemplary embodiment, an apparatus comprises: a first layer, wherein the first layer comprises a scaffold structure forming an inner lumen along a length of the scaffold structure, and wherein the first layer comprises a bioresorbable material; a second layer on the first layer, wherein the second layer comprises a bioresorbable material configured to expand, wherein the second layer is positioned on the first layer such that ends of the first layer extend beyond ends of the second layer; and an expandable balloon located within a distal end of the inner lumen of the first layer.

The balloon may be expandable through the inner lumen, collapsible through the inner lumen, and retractable from a distal end of the first layer through the inner lumen. The apparatus may further comprise an applicator serially coupled to a proximal end of the apparatus, the applicator comprising a multi-lumen tube having at least an irrigation lumen through which a fluid may be delivered to a patient and a drain lumen through which the fluid may be removed from the patient. The applicator may be serially coupled to the proximal end of the apparatus using a compression covering on a distal end of the applicator and the proximal end of the apparatus. The compression covering may comprise a sheath having a first sheath layer coupling the distal end of the applicator to the proximal end of the applicator. The sheath may further comprise a second sheath layer on the first sheath layer and covering from a distal end of the second layer to the proximal end of the applicator such that upon removal of the second sheath layer the second layer may be exposed to a liquid. The sheath may further comprise a third sheath layer on the second sheath layer and covering from a distal end of the first layer to the proximal end of the applicator. At least one of a distal end of the first layer or a proximal end of the first layer may be configured to expand into a funnel shape. The bioresorbable material of the second layer may be chitosan.

In another exemplary embodiment, an apparatus comprises: a scaffold structure forming an inner lumen along a length thereof, the scaffold structure being substantially tubular in shape and expandable in radial directions from an axis extending longitudinally through the tubular shape of the scaffold structure, an expandable layer on the scaffold structure and coveting a portion of the scaffold structure along a length thereof such that a distal end of the scaffold structure extends beyond a distal end of the expandable layer and a proximal end of the scaffold structure extends beyond a proximal end of the expandable layer, wherein a material of the second layer is configured to expand, and an expandable balloon located within the distal end of the scaffold structure.

The balloon may be accessible through the inner lumen. The balloon may be expandable through the inner lumen by injection of a liquid or a gas. The balloon may be expandable through the inner lumen and collapsible and retractable through the inner lumen. The apparatus may further comprise an applicator comprising a multi-lumen tube having at least an irrigation lumen through which a fluid may be delivered through the apparatus and to a patient and a drain lumen through which the fluid may be removed through the apparatus and from the patient, and a compression covering serially coupling the multi-lumen tube to the proximal end of the apparatus. The compression covering may comprise a first sheath layer coupling a proximal end of the scaffold structure to the applicator, a second sheath layer covering the expandable layer, and a third sheath layer covering from the distal end of the scaffold structure to the multi-lumen tube. A material of the scaffold structure and the material of the expandable layer may each comprise a bioresorbable material. The bioresorbable material of at least the expandable layer may comprise chitosan.

In another exemplary embodiment, a method comprises: inserting an apparatus into a prostatic urethra of a patient, wherein the apparatus comprises a stent comprising a first layer comprising a scaffold structure of a bioresorbable material forming an inner lumen along a length of the scaffold structure, a second layer on the first layer, the second layer comprising a bioresorbable material configured to expand and being positioned on the first layer such that ends of the first layer extend beyond ends of the second layer, and an expandable balloon located within a distal end of the inner lumen of the first layer; expanding the balloon to position the stent in the prostatic urethra; expanding the second layer to cause the second member to press against an inner surface of the prostatic urethra; and collapsing the balloon and retracting the balloon through the inner lumen.

Expanding the balloon may comprise injecting the balloon with a liquid or a gas. Expanding the second layer may comprise exposing the second layer to a liquid draining through the prostatic urethra. The method may further comprise serially coupling an applicator to a proximal end of the stent. Exposing the second layer to the liquid draining through the prostatic urethra may comprise removing a sheath layer at least partially serially coupling the applicator to the proximal end of the stent.

It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the invention is intended to embrace all such alternatives, modifications, and variances which fall within the scope of the appended claims.