Devices for treatment of benign prostatic hyperplasia and related lower urinary tract symptoms

Abstract

To provide a sheath for retrieving an implant from a location within a body lumen or for placing the implant at the location.SOLUTION: A sheath comprises: an elongated shaft member; and a hub which is fixed to an outer surface of a proximal end portion of the elongated shaft member. The hub includes: a proximal portion in the form of a truncated cone which is configured to engage with a flared portion of the proximal end portion of the elongated shaft member; and a distal portion which is configured to engage with an outer surface of the flared portion of the proximal end portion of the elongated shaft member and be screwed to the proximal portion so as to cooperatively compress and secure the flared portion of the proximal end portion of the elongated shaft member together with the proximal portion, thereby forming a sealed connection.SELECTED DRAWING: Figure 3

Description

Disclosed Content

[0001] [Related Application This application claims the benefit of U.S. Provisional Application No. 62 / 943,112, filed on December 3, 2019. The priority of this application is expressly claimed, and the disclosure thereof is hereby incorporated by reference in its entirety into this specification.

[0002] [Field of the Disclosure The present disclosure relates to devices for managing or treating body tissue that occludes a hollow body lumen, such as prostate tissue that occludes the urethra.

[0003] [Background The prostate is a walnut-shaped gland that surrounds the urethra through which urine is discharged from the bladder and plays an important role in the male reproductive system. This gland is initially small but tends to enlarge as a man ages. When the prostate enlarges excessively, a disease known as benign prostatic hyperplasia (BPH) occurs. Benign prostatic hyperplasia (BPH) refers to an abnormal but non-malignant (non-cancerous) growth of the prostate that is very common in aging men. BPH is a chronic disease and is associated with the development of urinary outflow obstruction or luminal stenosis in the prostatic urethra. Bladder outlet obstruction (BOO) refers to an obstruction at the base of the bladder that reduces or stops the flow of urine into the urethra and may be secondary to BPH. A series of related diseases collectively referred to as lower urinary tract symptoms (LUTS) can occur, including sexual dysfunction, frequent urination, difficulty urinating, urinary retention, urinary leakage, and urinary tract infections and bladder infections that worsen as the abnormal growth of the prostate expands and progresses.

[0004] Surgical techniques relieve BPH by removing a substantial portion of the prostate tissue. Several conventional surgical techniques are available, all of which require hospitalization and some form of spinal anesthesia, epidural anesthesia, or general anesthesia. Transurethral resection of the prostate (TURP) is the primary surgical treatment for BPH and continues to be the gold standard against which other treatments are compared. Conventional surgical techniques differ in the location of the incision made by the surgeon to access the prostate and the method of removing the prostate tissue. For example, in some surgeries, laser energy, heat, or radiofrequency is used to remove tissue from the prostate. These include laser enucleation, photoselective vaporization (PVP), transurethral needle ablation (TUNA) using radiofrequency energy, transurethral microwave thermotherapy (TUMT), and transurethral incision of the prostate (TUIP). However, these conventional surgical approaches to the treatment of BPH are invasive, irreversible, and have significant drawbacks including several months of temporary catheterization, risk of infection, loss of sexual function, urinary incontinence, and restenosis. Recurrent hypertrophy of cells in the prostate can regrow and cause recurrence of urethral stricture, as well as recurrence of the LUTS symptoms described above.

[0005] Removing prostate tissue relieves some BPH symptoms, but tissue removal by conventional surgical approaches is irreversible and any side effects of the surgery can potentially afflict the patient for life or affect the patient's quality of life. Furthermore, surgical approaches are associated with the inherent risks of the surgery itself and the risk of recurrence due to regrowth of the removed prostate tissue and may require a recovery period as long as three to six weeks, depending on the extent of the disease and the specific surgical approach required for the individual patient.

[0006] Because the drawbacks of traditional surgeries have been recognized, less invasive treatment methods have been developed and can be selected by patients and physicians as an alternative to lifelong medication or surgery, depending on the extent of the disease. These less invasive treatment methods may be suitable for patients who do not wish to undergo, or are not medically appropriate to undergo, surgical procedures under general anesthesia. Additionally, younger patients also desire less invasive reversible treatments without compromising sexual function, leaving the option of undergoing permanent irreversible treatments that may affect sexual function in later years. Furthermore, less invasive treatment methods enable procedures to be performed in a hospital or clinic using local anesthesia, and the advantages include patient comfort and savings in the healthcare system compared to procedures under general anesthesia in a hospital setting.

[0007] Less invasive techniques include transurethral methods that actually remove enlarged prostate tissue, which are generally less traumatic than traditional surgeries, but both destroy prostate tissue and are irreversible. To avoid the destruction of prostate tissue, other treatment techniques have been developed that are designed to enlarge the diameter of the prostatic urethra without actually removing tissue from the prostate, such as by implanting a device designed to expand the diameter of the urethra into the prostatic urethra. Prostate implants involve a procedure in which a urologist inserts a small device into the prostatic urethra, which is narrowed by enlarged prostate tissue. Once in the correct position, this implant expands and helps to keep the urethra open by pushing out the tissue lobes, and is designed to protect the enlarged prostate tissue from total impingement and opening of the urethra. Ideally, the prostate implant is expected to eliminate the need for surgical removal of prostate tissue and reduce the risks of infection, sexual dysfunction, and incontinence, which are also inherent and traditional to less invasive surgical approaches. This procedure can also be designed to be reversible since the implant can be removed and additional surgical procedures can be performed in the future.

[0008] Accordingly, a hospital-based procedure for BPH / LUTS using a flexible cystoscope currently used to image the urinary tract, including the prostatic urethra, and diagnose BPH and related symptoms, involves placing an expander device implantable within the prostatic urethra, mechanically retracting the lobes, increasing the urethral lumen, and enabling urine passage. The expander can be made retrievable using a commercially available cystoscope, sheath, and grasper, or other retrieval tools used in urological procedures. Accordingly, it is desirable to provide a sheath having features configured to assist in retrieving the implant from the prostatic urethra at any point after implantation for a given duration. The techniques of the present disclosure satisfy these and other needs.

[0009] 〔SUMMARY〕 The present disclosure relates to a sheath for retrieving an implant from a placement location within a body lumen. The sheath can include an elongate shaft member having at least one lumen with an inner diameter, a non-traumatic distal end, and a proximal end. The shaft member has at least one region where the flexibility is altered. The distal end of the shaft member can be configured to compress the implant into a reduced profile.

[0010] In one aspect, a hub can be fixed to the proximal end of the elongate shaft member and has an opening that tapers from a proximal diameter larger than the inner diameter of the shaft member and is configured to advance a cystoscope through at least one lumen of the shaft member.

[0011] In one aspect, the hub can have a proximal portion and a distal portion that thread together such that the proximal end of the shaft member is fixed to the hub by compression. The proximal portion of the hub can have a frustoconical protrusion that engages a flare portion of the proximal end of the shaft member.

[0012] In one aspect, the hub can be further configured to form a seal with a cystoscope inserted through the opening.

[0013] In one aspect, the hub may be further configured to releasably secure a cystoscope inserted through the opening.

[0014] In one aspect, the region of the shaft member with altered flexibility may be adjacent to the distal end and may have a reduced durometer value compared to the proximal region of the shaft member. The region of the shaft member adjacent to the distal end can have a different material than the proximal region of the shaft member.

[0015] In one aspect, the region of the shaft member with altered flexibility adjacent to the distal end can be extremely flexible compared to the proximal and distal regions of the shaft member to allow for full articulation of the flexible cystoscope when introduced through the sheath. The region of the shaft member with altered flexibility adjacent to the distal end can have a lower thickness or can include features that enhance flexibility. For example, the proximal and distal ends may be reinforced with braided metal wires, and the region adjacent to the distal end may be reinforced with no metal braid or a lower density braid (or lower braid angle) to improve flexibility. Other features include, but are not limited to, laser etching linear or helical grooves in the region of the shaft member adjacent to the distal end to improve flexibility.

[0016] In one aspect, the shaft member can have a reinforcement configured to facilitate compression of the implant. The reinforcement can be at least one metal band. This reinforcement can be of a very short length, several millimeters, generally 1 - 15 mm, or more preferably 2 - 5 mm.

[0017] In one aspect, the distal end of the shaft member can have a tapered edge. The tapered edge can slope inwardly towards the inner diameter, such that the sheath follows the contour of the cystoscope while advancing through the urethra or other body lumen without causing trauma, injury or tissue damage and minimal pain to the patient during the procedure. The tapered edge of the sheath can be made softer compared to the distal end so as to provide a non-traumatic tip.

[0018] In one aspect, the distal end of the shaft member may be configured to seal with a cystoscope inserted through the shaft member.

[0019] In one aspect, the sheath can have a plurality of lumens. At least one lumen may be restricted within another lumen, or at least one lumen may be adjacent to another lumen.

[0020] In one aspect, the shaft member has an inner diameter in the range of 1.7 mm to 6.7 mm (5F to 20F) and an outer diameter in the range of 2.7 mm to 8.7 mm (8F to 26F).

[0021] In one aspect, the implant may be a prostate implant having an expandable profile configured to restore patency to the patient's urethra.

[0022] The present disclosure also includes a method for retrieving or placing an implant from or at a placement site within a body lumen. A sheath can be provided, the sheath including an elongated shaft member having at least one lumen with an inner diameter, a non-traumatic distal end, and a proximal end. The shaft member has at least one shaft member region with a modified flexibility. A cystoscope can be introduced through at least one lumen of the shaft member. The sheath and the cystoscope can be advanced through the body lumen. The implant can be retrieved or released via relative movement with the sheath.

[0023] In one aspect, the implant can be fixed to resist relative movement with the sheath. The implant can be compressed to a reduced profile within the sheath. Thus, thereafter, the sheath, the cystoscope, and the compressed implant can be withdrawn from the body lumen.

[0024] In one aspect, the cystoscope can be releasably fixed to the sheath before advancing the sheath and the cystoscope through the body lumen.

[0025] In one aspect, the compression of the implant can be confirmed by visualization.

[0026] In one aspect, the implant may be fixed by a gripper to resist relative movement with the sheath.

[0027] The present disclosure also includes a sheath for introducing a cystoscope and a delivery catheter including an implant for placement within a body lumen. The sheath can have an elongate shaft member having two or more lumens each having an inner diameter, a non-traumatic distal end, and a proximal end, a hub fixed to the proximal end of the elongate shaft member, and two or more openings within the hub, the openings each being tapered from a larger proximal diameter and configured to advance the cystoscope through one lumen of the shaft member and to advance the delivery catheter through another lumen of the shaft member.

[0028] Furthermore, the present disclosure also includes a method for placing an implant in a body lumen. The method may include providing a sheath including an elongate shaft member, a hub fixed to a proximal end of the elongate shaft member, and at least two openings of the hub each tapering from a larger proximal diameter. A cystoscope may be introduced through one opening and at least one lumen of the shaft member. A delivery catheter including the implant may be advanced through another lumen of the shaft member until the delivery catheter is visualized. The cystoscope can be fixed against relative movement with the sheath. The implant may be released at a target location within the body lumen. The sheath, cystoscope, and delivery system may be withdrawn from the body lumen.

[0029] Additional features and advantages will become apparent from the following more particular description of the preferred embodiments of the disclosure, as illustrated in the accompanying drawings. In the accompanying drawings, like reference numerals generally refer to the same parts or elements throughout the figures.

Brief Description of the Drawings

[0030]

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[0031] 〔Detailed Description〕 First, it should be understood that the present disclosure is not limited to the specifically exemplified materials, architectures, routines, methods, or structures, and thus can vary. Accordingly, some such options that are similar or equivalent to those described herein can be used in the practice or embodiments of the present disclosure, but the preferred materials and methods are described herein.

[0032] Also, it should be understood that the terms used herein are for the purpose of describing only specific embodiments of the present disclosure and are not intended to be limiting.

[0033] The detailed description set forth below in connection with the accompanying drawings is intended as an explanation of exemplary embodiments of the present disclosure and is not intended to represent the only exemplary embodiments in which the present disclosure can be practiced. The term "exemplary" used throughout this description means "serving as an example, instance, or illustration" and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a complete understanding of the exemplary embodiments of the specification. It will be apparent to those skilled in the art that the exemplary embodiments of the present specification can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the novelty of the exemplary embodiments presented herein.

[0034] For purposes of convenience and clarity only, terms indicating directions such as top, bottom, left, right, up, down, over, above, below, beneath, rear, back, and front may be used with reference to the accompanying drawings. These and similar terms indicating directions shall not be construed as limiting the scope of the disclosure in any way.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Further, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise.

[0036] Definition: The terms "therapeutically effective displacement" or "therapeutically effective retraction" or "therapeutically effective dilation" are used interchangeably herein and refer to the amount of displacement of prostatic tissue adjacent to a limited region of the urethra that is sufficient to increase the urethral lumen and treat, ameliorate, or prevent the symptoms of benign prostatic hyperplasia (BPH) or a co-morbid disease or condition, including lower urinary tract symptoms (LUTS), bladder outlet obstruction (BOO), and benign prostatic obstruction (BPO), and the displacement of the prostatic tissue exhibits a detectable therapeutic, preventive, or inhibitory effect. This effect can be detected, for example, by improvement in the clinical condition, or reduction in symptoms or absence of co-morbidities. Examples of clinical measures include a decrease in the International Prostate Symptom Score (IPSS), a decrease in the post-void residual (PVR) volume in the bladder, an increase in the maximum urinary flow rate (Qmax), or an improvement in quality of life (QoL), or an improvement in sexual health after treatment (Sexual Health Inventory for Men (SHIM) score, Male Sexual Health Questionnaire (MSHQ) score for men). The exact distance or amount of displacement of the prostatic tissue is determined by the weight, size, and health status of the subject; the nature and degree of the hypertrophied or diseased prostatic condition, and the size of the implant selected for placement within the patient.

[0037] As used herein, a patient "in need of treatment for BPH" is a patient who would benefit from the presence of hypertrophied prostatic tissue caused by non-malignant enlargement of the prostate and related disorders including LUTS, urinary outflow obstruction symptoms, and luminal stenosis of the prostatic urethra, or from a reduction in symptoms resulting therefrom. As used herein, the terms "implant" or "expander" or "device" refer to a prosthetic device implanted within the prostatic urethra to alleviate LUTS associated with or caused by BPH.

[0038] As used herein, the term "tissue engagement" with respect to an arm, strut, or other extension of the structure of an implant refers to the length of the physical structure of the implant that engages prostatic tissue along the major portion of the lobe of an organ that compresses the urethra and limits the tissue from further affecting the patency of the urethra. "Tissue retraction" refers to the ability of the structure of the implant to exert the force necessary to move tissue away from the compressed or stenotic urethra. This necessary force can be provided by the inherent structure of the implant or, particularly, when the implant is manufactured from a shape memory or superelastic material having a predetermined expanded configuration designed to exert the necessary tissue retraction force when engaged with hypertrophied prostatic tissue, by expansion of the implant from a compressed configuration to an expanded configuration. The lengths of the tissue engagement or tissue retraction structural features that contact within these definitions are spaced away from the intralobular grooves that extend along the length of the prostate surrounding the urethra and require contact with the length of tissue along the lengths of the two lateral lobes or the lateral and middle lobes.

[0039] With respect to the various structural orientations and anatomical-related expressions described herein, the terms "proximal" and "distal" are related to the perspective of a medical professional such as a urologist operating the delivery system of the present disclosure to deploy the implants described herein. Thus, the features of the delivery system held by the hand of the urologist are at the "proximal" end, and the assembled system and implant, which is initially in a compressed configuration, is located at the "distal" end of the delivery system.

[0040] Referring to FIG. 1, a cross-sectional view of the male anatomical structure shows the prostate gland 1 surrounding the urethra 2. The urethra 2, in a normal state, provides fluid communication from the urine stored in the bladder 3 that is to be expelled from the body under voluntary muscle control of the external urethral sphincter. Normal or “true” prostate tissue 4 surrounds the urethra 2 and, in the absence of disease, does not affect the patency of the urethra 2. In patients suffering from benign prostatic hyperplasia (BPH), the urethra 2 is constricted by hypertrophic tissue, i.e., prostate tissue 4 that shows excessive growth towards the urethra 2. This excessive non-cancerous cell growth results in the symptoms of BPH described above, including lower urinary tract symptoms (LUTS) and urinary outflow obstruction, and urinary incontinence. In FIG. 1, the implant 5 delivered using the devices and systems of the present disclosure is illustrated engaging the prostate tissue 4 along the length of the implant 5 to restore the patency of the urethra 2 and to allow urine flow from the bladder 3 to be unobstructed. As illustrated, the selective placement of the implant 5 at the target site between the bladder neck opening 6 and the seminal colliculus 7 is an important feature to prevent the implant 5 from puncturing, perforating, or incising the surrounding tissue. The implant 5 is designed to remain in the correct position within the prostatic urethra 2. The implant 5 does not extend into the bladder 3 where the structural material of the implant 5 would be constantly exposed to urine, which could form a coating or otherwise degrade, causing complications and making retrieval even more difficult, and the implant 5 does not interfere with the voluntary control of the external urethral sphincter or sexual function.

[0041] The implant 5 according to the technology of the present disclosure has a plurality of tissue engagement structures that exert a force on the hypertrophied prostate tissue 4 adjacent to the urethra 2. As described below, the number of the plurality of tissue engagement structures can be two, four, or tissue engagement extensions, such as struts or arms, exceeding four. The use of three extensions is avoided when the three extensions are oriented to fit respectively within the intralobular grooves of the prostate 4. Thus, any plurality of tissue engagement structures are possible as long as the structures are asymmetrically oriented to ensure that the implant 5 is oriented outside the three intralobular grooves formed by the length of the tissue contact between the two lateral lobes and one middle lobe. Embodiments using three tissue engagement structures can be used to treat the anatomical structure when the anatomical structure of the urethra consists of both lateral lobes and the third lobe is not involved in urethral stricture.

[0042] The implant 5 can be manufactured from shape memory materials, alloys, spring materials, and superelastic materials including nitinol (nickel-titanium alloy), nitinol-based alloys, cobalt-chromium alloys, spring steel, and spring stainless steels. Other known shape memory materials include polyetheretherketone (PEEK), as well as shape memory and bioabsorbable polymers and metals (polylactic acid, polyglycolic acid and their copolymers; magnesium alloys). The above materials may be coated with a thin film coating to prevent outer coating formation, corrosion and calculus formation. The coating can include ceramic materials such as alumina, silicon carbide, silicon nitride and zirconia, as well as other ceramic coatings that are inert to urine, prevent outer coating formation and calculus formation, and prevent degradation of the materials forming the implant in a chemical or urinary environment. The coating may also be a polymer such as polytetrafluoroethylene (PTFE), parylene, silver and other antibacterial coatings, silicone derivatives, and other similar materials recognized by those skilled in the art.

[0043] The implant 5 may also include a therapeutic coating adhered to the surface of the implant 5 to elute drugs after being implanted into the prostatic urethra 2 in a manner known as a drug-eluting implant to elute drugs gradually to reduce hypertrophy and tissue growth. The coating contains pharmaceutically active anti-inflammatory and anti-proliferative agents, including sirolimus, novolimus, everolimus, biolimus, zotarolimus, paclitaxel, and others, which are used to prevent restenosis.

[0044] The implant 5 may also be coated with a drug for treating BPH symptoms. Such embodiments have the advantage of using a high locally high tissue dose in the affected prostatic region of the urethra 2 to enhance effectiveness so as to relax smooth muscle cells and reduce tissue growth and the size of the prostate 4 without suffering side effects from drugs circulating in other parts of the body. Potential drug candidates include alpha-adrenergic blockers such as alfuzosin, doxazosin, tamsulosin, terazosin, and silodosin. Other drug candidates include 5-alpha-reductase inhibitors such as dutasteride and finasteride, as well as anticholinergic drugs. Other drug candidates are anticholinergic drugs such as oxybutynin, fesoterodine, darifenacin, tolterodine tartrate, tolterodine, solifenacin. Combinations of drugs including an alpha blocker + 5-alpha reductase inhibitor or an alpha blocker + anticholinergic drug can also be coated on the surface. Furthermore, anti-infective drugs or antibacterial drugs or antibiotics such as fluoroquinolones (e.g., ciprofloxacin), macrolides, tetracyclines, and trimethoprim.

[0045] Typically, the drug is mixed with a solvent and a polymer to form a solution, which is spray-coated onto the outer surface of the implant 5 to achieve the desired drug release characteristics. The manufacturing process is similar to that used for drug-eluting stents for the treatment of coronary artery disease. In many cases, the coating may be on the anti-lumen side to ensure more effective drug release and deposition within the urethral tissue of the prostatic urethra 2 and to minimize washout during urine flow. Also, the drug may be deposited within microreservoirs or microdepots on the outer surface of the implant 5 for filling the drug and may be coated by a polymer coating to controllably elute the drug into the urethral tissue. Typical polymers used for filling the drug are polylactic acid (PLA), poly-L-lactic acid (PLLA), polyglycolic acid (PGA), and their copolymers; polyurethanes; poly(methyl methacrylate) (PMMA) or poly(n-butyl methacrylate) (PBMA); and combinations thereof. Other polymers and solvents may be used by those skilled in the art to fill sufficient drug and maintain coating integrity with the implant surface. Multiple layers of coating may be used to achieve the desired drug filling and sustained release characteristics.

[0046] The implant 5 for restoring the patency of the urethra 2 can be removed after implantation by using a sheath 10, a gripper, and a cystoscope (not shown) in accordance with the techniques of the present disclosure, such as the retrieval sheath 10 shown in FIG. 2. In this exemplary embodiment, the sheath 10 includes an elongated tubular shaft member 12 having a hub 14 at the proximal end 16 and a distal end 18. During retrieval, relative movement between the sheath 10 and the implant 5 (not shown in this figure) allows the implant 5 to be compressed inside the sheath 10 and removed from the patient. As understood, the relative movement can occur by distal movement of the sheath 10 while the implant 5 is held relatively stationary by a gripper, proximal movement of the implant 5 being pulled by the gripper while the sheath 10 is held relatively stationary, or some combination of these movements.

[0047] To further assist in the description of this embodiment, FIG. 3 is a cross-sectional view showing details of the hub 14 and the proximal shaft end 16. As shown, the hub 14 features a beveled opening 20 having a relatively large proximal diameter that tapers to a relatively small distal diameter corresponding to the inner diameter of the shaft member 12. As will be appreciated, the relatively large proximal diameter of the opening 20 facilitates the insertion of the cystoscope that can be advanced through the lumen 22 of the shaft member 12. The hub 14 features a frustoconical proximal portion 24 that is engaged with the distal portion 26 by threads, and these cooperate to compress the flared end of the proximal end 16 of the shaft 12 against the frustoconical proximal portion 24 to form a sealed connection. If desired, an adhesive or other similar technique can be further used to enhance the adhesion between the shaft 12 and the hub 14.

[0048] Furthermore, FIG. 4 schematically shows a detailed view of the distal end portion 18 of the shaft 12. To facilitate retrieval of the implant 5, the distal end portion 18 is configured to have sufficient column strength to crush the implant 5 while the implant 5 is being drawn into it using a gripper. Further, the distal end portion 18 is configured to allow maneuverability and / or articulation of a flexible cystoscope advancing through the lumen 22 while reducing or minimizing anatomical trauma. To enable this, the sheath 10 can be designed to include one, all, or a combination of the following features. The distal tip portion 18 can utilize a polymer material with a different durometer than the main shaft 12. The distal end portion 18 is reinforced with one or more metal rings 24 (one skilled in the art will understand that braiding, coiling, and other configurations can also be used to provide the desired reinforcement) and can provide additional resistance to radial expansion and / or column strength, thereby helping to crush the implant 5 when it is drawn into the sheath 10. In such an embodiment, the metal ring 24 can be made of a stronger and harder (higher modulus of elasticity) material such as stainless steel, titanium, titanium alloy, cobalt-chromium alloy, or other biocompatible metals and alloys commonly used in medical devices. Further, the distal end portion 18 can be characterized by a region 26 not supported by the metal reinforcement. The intermediate region 26 has a modified flexibility and can be manufactured using a different (softer, lower modulus) material, such as a medical polymer or extrudate commonly used in medical devices, or a material with a low durometer, to exhibit greater flexibility compared to the distal end portion 18 and the proximal end 12. The region 26 may also have a lower wall thickness compared to the rest of the sheath 10. Also, other features to enhance flexibility, such as straight or helical grooves, may be included without compromising the structural integrity of the sheath. Such extreme flexibility in the region 26 does not significantly limit the range of articulation, maneuverability, or movement of the flexible cystoscope when inserted through the sheath 10. The softer region may be 1 to 50 mm in length, for example, 2.5 to 7.5 mm.Furthermore, the distal end 18 may have a tip with a tapered edge 28, which makes the transition between the cystoscope advancing through the inner lumen 22 and the outer diameter of the shaft member 12 smoother. The tapered edge 28 may be tapered inwardly, and the sheath tip does not bend outwardly while advancing the sheath, together with the cystoscope within the sheath 10, through a tortuous (or non-linear) urethral lumen (or other body lumen) and does not cause trauma and damage to the tissue. Additionally, such a configuration minimizes pain when the sheath 10 and the cystoscope advance through the prostatic urethra 2 under local anesthesia and facilitates procedures in a hospital or clinic without the need for general anesthesia. In other embodiments, the edge may also be rounded to prevent trauma or damage to the tissue during advancement within the body lumen. Furthermore, the distal end 12 can be configured to seal over the cystoscope as the cystoscope advances through the lumen 22. To achieve this, at least a portion of the distal end 18 can be formed from the same material as the remainder of the shaft member 12 or, if desired, a more elastic material including, but not limited to, polyurethane, silicone, etc.

[0049] The optional aspect of the hub 14 is to include a silicone, rubber, or other elastomeric material 30 (FIG. 3) to facilitate forming a seal between the cystoscope advancing through the lumen 22 and the sheath 10 to reduce backflow of body fluids. The seal may or may not require additional user input or steps to enable a complete seal. In one embodiment, the seal is shaped and sized such that insertion of the cystoscope automatically forms a seal between the sheath 10 and the cystoscope. In another embodiment, the hub 14 can be rotated, pushed, or interacted with to manually close the seal on the cystoscope. In such an embodiment, the seal also secures the position of the sheath 10 relative to the cystoscope during retrieval of the expander device. This facilitates advancement of the cystoscope and sheath 10 as a system (without relative slippage) without affecting the maneuverability of the flexible cystoscope during advancement of the sheath 10, advancement of the grasper, and grasping of the implant 5. Once the implant 5 is securely held, the hub 14 is loosened to allow relative advancement of the shaft member 12 over the implant 5 to crush the implant 5 within the lumen 22 of the shaft member 12. Once the implant 5 is inside the shaft member 12, the hub 14 is tightened again to securely attach the shaft member 12 to the inserted cystoscope. The system can be easily retrieved without relative movement between the sheath 10 and the cystoscope and without damaging the wall of the cystoscope and the urethra 2.

[0050] The shaft member 12 and the hub 14 have openings configured to allow insertion of a cystoscope or other endoscopic instrument to visualize anatomical features and assist in a procedure. The inner diameter of the shaft member 12 (schematically shown in FIG. 4) can range from 1.7 to 7.3 mm (5 to 22 Fr), or more preferably from 2.7 to 6.0 mm (8 to 18 F), to allow passage of instruments having different diameters. The outer diameter of the shaft member 12 (also schematically shown in FIG. 4) is designed to be as small as possible to minimize trauma to the anatomical passage and strong enough to allow advancement of the instrument, and can range from 1.7 to 8.3 mm (5 to 25 Fr), or more preferably from 3.0 to 7.0 mm (9 to 21 F). As a non-limiting example, the sheath 10 can have an inner diameter of 6.7 mm (20 F) and an outer diameter of 8.0 mm (24 F). The overall length of the sheath 10 is sufficient to reach the location of the implant 5 within the prostate 4 through the patient's urethra 2 and can be, for example, about 32 cm. The overall length can range from 20 to 50 cm depending on the patient's anatomical structure and the lengths of the different cystoscopes used during the procedure. Similarly, the hub 14 has an opening 20 configured to allow insertion of a cystoscope or other endoscopic instrument to visualize anatomical features and assist in a procedure. The inner diameter of the hub 14 can range from 1.7 to 7.3 mm (5 to 22 Fr), or more preferably from 2.7 to 6.0 mm (8 to 18 F), to allow passage of instruments having different diameters. The outer diameter of the hub 14 is designed to be ergonomic for the user and can range from 2 to 50 mm, or more preferably from 10 to 20 mm.

[0051] The shaft member 12 is desirably thin, flexible, soft, and strong enough to easily advance without kinking. In one embodiment, the shaft member 12 is formed from a reinforced polymer extrusion. For example, the polymer extrusion can be made of materials such as PEBA (polyether block amide), polytetrafluoroethylene (PTFE), etc. The extrusion can also be a multi-layer structure using different polymers or the same polymer but having different hardnesses. The reinforcing material can be a metal such as stainless steel, nitinol, etc., or a polymer such as PEEK (polyether ether ketone), nylon, etc. The reinforcing material can be arranged in a coil or braided pattern and does not necessarily extend over the entire length of the sheath 10. Alternatively, the shaft member 12 can be composed of only the extruded polymer. The sheath 10 can also be characterized by a liner 32 (FIG. 4) along the inner diameter to help facilitate the advancement of the cystoscope or other instrument by reducing friction. The liner can be made of PTFE, nylon, or other materials with a low coefficient of friction. The sheath 10 can also be coated with an additional lubricious or hydrophilic material on the outer diameter to help facilitate advancement through the urinary tract. A suitable wall thickness for the sheath 10 is 0.0254 - 0.635 mm (0.001 - 0.025 inches), or more preferably 0.0762 - 0.381 mm (0.003 - 0.015 inches). As described above, the hub 14 provides an angled opening 20 to facilitate the introduction of the cystoscope or other instrument and also functions as a handle for the user to hold and manipulate the sheath 10 during retrieval of the implant 5. The hub 14 can be composed of polycarbonate plastic or other suitable materials including most thermoplastic polymers or metals.

[0052] In other embodiments, the sheath 10 according to the techniques of the present disclosure can use a shaft 12 having a plurality of lumens. An example is schematically shown in the cross-section of FIG. 5 of a shaft member 12 having two adjacent lumens 34 and 36. The inner diameters of the lumens 34 and 36 may have different inner diameters as shown for accommodating a cystoscope and other auxiliary devices, or may have the same diameter in an alternative embodiment. Another example of a sheath 10 with multiple lumens is schematically shown in FIG. 6, which shows a shaft member 12 having a first lumen 38 and a second lumen 40 defined within the first lumen 38 by an inner tubular member 42. The shaft member 12 and the inner tubular member 42 can share a common portion of their respective circumferences, and the second lumen 40 is restricted within the first lumen 38, having a crescent shape configuration as shown. Alternatively, the inner tubular member 42 may be coaxially disposed within the shaft member 12 to form concentric lumens. As will be understood, in any of these alternative embodiments, the shape and dimensions of the multiple lumens can optimize their respective inner dimensions within the constraints of the overall cross-sectional area of the shaft member 12 and be configured to be adjusted to fit the profiles of different cystoscopes or other instruments. The shaft member 12 may be made from a multi-lumen extruded product having two or more lumens. The separate lumens allow for the advancement of a cystoscope, a grasper, and other instruments, or irrigation through the lumen. Such embodiments are characterized by a reduced outer diameter or profile in order to minimize patient discomfort and trauma during the introduction and treatment of the device.

[0053] As will be appreciated by those skilled in the art, sheaths having multiple lumens as described in FIGS. 5 and 6 also require different hubs having multiple lumens, sizes (length and diameter), and shapes to accommodate the introduction of different types of cystoscopes (disposable and / or reusable digital video cystoscopes and / or flexible and rigid fiber scopes) as well as other auxiliary devices or instruments (flexible and rigid graspers) during a medical procedure.

[0054] Furthermore, such a sheath 10 can be used not only for the retrieval of the implant 5 but also for the placement of the implant 5 using a cystoscope. For example, one of the lumens can be used to introduce the cystoscope, and another lumen can be used to introduce a delivery catheter together with the implant 5 and deploy it at the target location. The length, number of lumens, and lumen size of the sheath 10 can be optimized according to the specific instruments used in the medical procedure. Typically, the inner diameter of the lumen 34 for introducing a cystoscope with an outer diameter of 1.7 mm to 6.0 mm (5F to 18F) ranges from 2.0 mm to 6.7 mm (6F to 20F), and the inner diameter of the lumen 36 for introducing a delivery catheter with an outer diameter of 1.7 mm to 4.0 mm (5F to 12F) ranges from 2.0 mm to 4.7 mm (6F to 14F). The typical length of the sheath 10 ranges from 20 to 50 cm, depending on the type of cystoscope used during the medical procedure. Similarly, the lumens 38 and 40 can be designed and optimized to introduce various medical instruments into the body lumen using the lowest-profile sheath 10 to minimize trauma and damage. To achieve the desired properties, different materials (with different strengths and elastic moduli or durometers; reinforced or not reinforced with braided wires), dimensions (thicknesses) can be selected for the proximal portion, central portion, and distal portion of the sheath 10, as well as for the hub 14. In some embodiments, the hub 14 can incorporate a perfusion port for saline perfusion to facilitate imaging during the medical procedure.

[0055] Subjects diagnosed with BPH / LUTS can be treated using an implant 5 to open the occluding lobe in the prostatic urethra 2. The implant 5 is placed between the bladder neck 6 and the seminal colliculus 7 for a predetermined period ranging from 30 days to several (1 - 5) years. Whenever desired, the implant 5 can be retrieved using a retrieval sheath according to the techniques of the present disclosure. One exemplary routine includes inserting a flexible cystoscope through the angled opening 20 of the hub 14 into the sheath 10 such that the sheath 10 does not interfere with the articulation of the flexible cystoscope. In particular, the flexible cystoscope may be advanced through the hub 14 and the shaft member 12 of the sheath 10 until the cystoscope exits the distal end 18. In one embodiment, the distal end of the cystoscope tip should extend about 2 - 5 cm beyond the tip at the distal end 18 of the sheath 10 while checking the maneuverability of the cystoscope. In embodiments featuring sealing the cystoscope or a hub 14 attached to the cystoscope, appropriate operations can be performed to fix the cystoscope and the sheath 10 together. Next, the cystoscope and the sheath 10 are inserted into the patient's urethra 2 as a system to the location of the implant 5 until the implant 5 (or other target device) is visible. As schematically shown in FIG. 7, the grasper 8 is inserted through the working channel of the cystoscope 9 and operated to hold or fix the implant 5 in the correct position. Once the implant 5 is firmly grasped, the retrieval sheath 10 is advanced forward (distally) on the cystoscope 9, and the implant 5 is gradually crushed into a small profile at the distal end 18 as it is drawn into the sheath 10 under direct visualization of the cystoscope 9. As described above, the grasping portion 8 can also be used to pull the implant 5 proximally within the sheath 10, such as by simultaneously retracting the grasping portion 8 and the cystoscope 9, or a combination of these movements can be used to cause the necessary relative movement. The implant 5 is compressed or crushed into a lower profile when the sheath 10 is pushed or advanced over it. A visual confirmation that the implant 5 is sufficiently compressed within the sheath 10 can be obtained when the distal edge of the implant 5 is barely visible by the cystoscope 9.Once the implant 5 comes inside the sheath 10, the retrieval sheath 10, the cystoscope 9, and the grasper 8 are removed from the urinary tract simultaneously.

[0056] Correspondingly, it will be understood from the above disclosure that sheaths according to these techniques can be used at any point after the placement of implant 5, for example, immediately after implantation or after any given duration. As will be described in further detail, the present disclosure describes a sheath 10 that meets a plurality of performance requirements including any or all of the following characteristics. Sheath 10 can be non-traumatic to urethra 2 and the surrounding anatomical structures within the body during forward and backward advancement of sheath 10 through the urinary system. Sheath 10 can facilitate the retrieval of implant 5 under direct visualization of a commercially available flexible cystoscope 9 using a commercially available grasper 8 such as a laparoscopic grasper. The distal end of sheath 10 can be strong enough with respect to radial expansion and column strength to crush implant 5 into a smaller profile without causing torsion when implant 5 is pulled within sheath 10. Sheath 10 can hold implant 5 in a constrained (compressed to a low profile or small diameter) configuration such as less than 6.0 mm (18F) after implant 5 is placed within sheath 10. Sheath 10 is configured to minimize pain or bleeding caused during use and to minimize discomfort to the patient. Sheath 10 is configured to have a length sufficient to reach a target site including prostatic urethra 2 and bladder 3. Sheath 10 is configured to be compatible with the lengths of all commercially available flexible cystoscopes, for example, about 40 - 60 cm. Sheath 10 is configured to be sufficiently flexible and compliant to easily pass through the tortuous portion of urethra 2 from the penis to bladder 3. Sheath 10 is configured to be sufficiently flexible so as not to significantly impede the operability of the cystoscope at the distal end and to be able to visualize anatomical features and landmarks (external sphincter, seminal colliculus, bladder neck, and bladder) during forward advancement and deployment. Sheath 10 can also be configured to be fixed / locked onto cystoscope 9 during forward advancement and after implant 5 is compressed within sheath 10. Sheath 10 may also be configured to enable use by a single operator using flexible cystoscope 9 and grasper 8 to retrieve implant 5 without the need for an assistant.

[0057] It should be noted that the previously available devices are not configured to be used in the above method together with a flexible cystoscope for retrieving a prostate implant. Existing sheaths with a smaller diameter cannot accommodate a 5.7 mm (17F) cystoscope, while larger sheaths are rigid and can damage the urethra when advancing through the tortuous prostatic urethra, causing discomfort and pain to the patient. Further, conventional sheaths typically have a very stiff valve, which, despite the use of a medical-grade lubricant, makes the insertion of the scope through the sheath or the advancement of the sheath over the cystoscope very difficult.

[0058] The exemplary embodiments disclosed above are merely intended to illustrate the various utilities of the present disclosure. Numerous modifications, variations, and combinations of the functional elements and features of the present disclosure are possible in light of the above teachings, and thus, within the scope of the appended claims, the present disclosure can be practiced other than as particularly disclosed, and it is understood that the principles of the present disclosure can be readily extended to other applications with appropriate modifications.

[0059] All patents and publications are incorporated herein by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. Although the present disclosure has been specifically disclosed by way of preferred embodiments and optional features, modifications and variations of the concepts disclosed herein may be made by those skilled in the art, and it is to be understood that such modifications and variations are considered to be within the scope of the present disclosure.

[0060] 〔Embodiments〕 (1) A sheath for retrieving an implant from a placement location within a body lumen or for placing the implant at the placement location, An elongate shaft member having at least one lumen with an inner diameter, a non-traumatic distal end, and a proximal end, and having at least one shaft member region with a changed flexibility, wherein the non-traumatic distal end is positioned opposite the proximal end, and the non-traumatic distal end is configured to compress the implant to a reduced profile, a sheath. (2) A hub fixed to the proximal end of the elongate shaft member, and an opening of the hub that is tapered from a proximal diameter larger than the inner diameter of the shaft member and is configured to advance a cystoscope through the at least one lumen of the shaft member, further included in the sheath according to Embodiment 1. (3) The hub includes a proximal portion having a frustoconical protrusion that engages with a flare portion of the proximal end of the shaft member, and a distal portion, and these are screwed together such that the proximal end of the shaft member is fixed to the hub by compression, the sheath according to Embodiment 2. (4) The hub is further configured to form a seal with a cystoscope inserted through the opening, the sheath according to Embodiment 2. (5) The hub is further configured to releasably fix a cystoscope inserted through the opening, the sheath according to Embodiment 2.

[0061] (6) The shaft member region with a changed flexibility is adjacent to the non-traumatic distal end and has a reduced durometer value compared to the proximal region of the shaft member, the sheath according to Embodiment 1. (7) The shaft member region adjacent to the non-traumatic distal end includes a material different from that of the proximal region of the shaft member, the sheath according to Embodiment 6. (8) Further including a reinforcing material configured to facilitate compression of the implant, the sheath according to Embodiment 1. (9) The reinforcing material includes at least one metal strip, the sheath according to Embodiment 8. (10) The non-traumatic distal end of the shaft member has a tapered edge, the sheath according to Embodiment 1.

[0062] (11) The non-traumatic distal end of the shaft member is configured to be sealed with a cystoscope inserted through the shaft member, the sheath according to Embodiment 1. (12) The sheath includes a plurality of lumens, the sheath according to Embodiment 1. (13) The sheath according to Embodiment 12, wherein at least one lumen is circumscribed within another lumen. (14) The sheath according to Embodiment 12, wherein at least one lumen is adjacent to another lumen. (15) The shaft member has an inner diameter in the range of 1.7 mm to 6.7 mm (5F to 20F) and an outer diameter in the range of 2.7 mm to 8.7 mm (8F to 26F), the sheath according to Embodiment 1.

[0063] (16) The implant is a prostate implant having an expandable profile configured to restore patency to a patient's urethra, the sheath according to Embodiment 1. (17) A method for retrieving an implant from or placing the implant at a placement location within a body lumen, comprising: providing a sheath including an elongate shaft member having at least one shaft member region with a changed flexibility and a non-traumatic distal end; introducing a cystoscope through at least one lumen of the shaft member; advancing the sheath and the cystoscope through the body lumen; retrieving or releasing the implant via relative movement with the sheath. (18) The step of retrieving the implant includes fixing the implant against relative movement with the sheath, compressing the implant to a reduced profile within the sheath, and withdrawing the sheath, the cystoscope, and the compressed implant from the body lumen, the method according to Embodiment 17. The method according to embodiment 17, further comprising releasably fixing the cystoscope to the sheath before advancing the sheath and the cystoscope through the lumen of the body. The method according to embodiment 18, further comprising confirming compression of the implant by visualization.

[0064] The method according to embodiment 18, wherein the implant is fixed by a gripper to resist relative movement with the sheath. A sheath for introducing a cystoscope and a delivery catheter including an implant for placement within a body lumen, an elongate shaft member having two or more lumens each having an inner diameter, a non-traumatic distal end, a proximal end, and at least one shaft member region with altered flexibility, a hub fixed to the proximal end of the elongate shaft member, and two or more openings within the hub, the openings each being tapered from a larger proximal diameter and configured to advance a cystoscope through one lumen of the shaft member and to advance a delivery catheter through another lumen of the shaft member. The sheath according to embodiment 22, wherein the hub is further configured to form a seal with the cystoscope inserted through the opening. A method for placing an implant within a body lumen, providing a sheath including an elongate shaft member having at least one shaft member region with altered flexibility and a non-traumatic distal end, a hub fixed to the proximal end of the elongate shaft member, and at least two openings of the hub each being tapered from a larger proximal diameter, introducing a cystoscope through one opening and at least one lumen of the shaft member, advancing the delivery catheter through another lumen of the shaft member until the delivery catheter including the implant is visualized, fixing the cystoscope so as to resist relative movement with respect to the sheath; releasing the implant at a target location within the body lumen; and withdrawing the sheath, the cystoscope, and the delivery catheter from the lumen of the body. A method comprising these steps.

Claims

1. A sheath for retrieving an implant from or placing the implant at a placement location within a body lumen, the sheath comprising: an elongate shaft member having at least one lumen with an inner diameter configured to allow a cystoscope to advance therethrough, a non-traumatic distal end, and a proximal end, the elongate shaft member having at least one shaft member region having a flexibility different from that of the non-traumatic distal end and the proximal end, the proximal end having a tubular portion, a flare portion, an inner surface, and an outer surface, the non-traumatic distal end being positioned opposite the proximal end, the non-traumatic distal end being configured to compress the implant to a reduced profile; a hub fixed to the outer surface of the proximal end of the elongate shaft member, the hub comprising: i) a proximal portion frustoconical in shape and configured to engage the flare portion of the proximal end of the elongate shaft member; ii) a distal portion configured to engage the outer surface of the flare portion of the proximal end of the elongate shaft member, the distal portion being screwed to the proximal portion and configured to cooperate with the proximal portion to compress and fix the flare portion of the proximal end of the elongate shaft member together to form a sealed connection; a hub; a sheath.

2. The sheath of claim 1, wherein the hub is further configured to include silicone, rubber, or other elastomeric material to facilitate forming a seal with the cystoscope inserted through an opening of the hub.

3. The sheath of claim 1, wherein the hub is further configured to releasably fix the cystoscope inserted through an opening of the hub.

4. The sheath of claim 1, wherein the shaft member region is adjacent to the non-traumatic distal end and has a reduced durometer value compared to the proximal region of the elongate shaft member.

5. The sheath of claim 4, wherein the shaft member region adjacent to the non-traumatic distal end includes a material different from that of the proximal region of the elongate shaft member.

6. The sheath of claim 1, further comprising a reinforcing member configured to facilitate compression of the implant.

7. The sheath according to claim 6, wherein the reinforcing member includes at least one metal strip.

8. The sheath according to claim 1, wherein the atraumatic distal end of the elongated shaft member has a tapered edge.

9. The sheath according to claim 1, wherein the atraumatic distal end of the elongated shaft member is configured to be sealed by the cystoscope inserted through the elongated shaft member.

10. The sheath according to claim 1, wherein the sheath includes a plurality of lumens.

11. The sheath according to claim 10, wherein at least one of the plurality of lumens is restricted within another lumen.

12. The sheath according to claim 10, wherein at least one of the plurality of lumens is adjacent to another lumen.

13. The sheath according to claim 1, wherein the elongated shaft member has an inner diameter in the range of 1.7 mm to 6.7 mm (5F to 20F) and an outer diameter in the range of 2.7 mm to 8.7 mm (8F to 26F).

14. The sheath according to claim 1, wherein the implant is a prostate implant having an expandable profile configured to restore patency to the patient's urethra.

15. The proximal portion includes a cylindrical distal lumen having an inner diameter corresponding to the inner diameter of the elongated shaft member, and a proximal opening that is tapered from a proximal diameter larger than the inner diameter of the elongated shaft member to a distal diameter corresponding to the inner diameter of the elongated shaft member. The sheath according to claim 1.

16. The sheath according to claim 6, wherein the shaft member region does not include the reinforcing member.

17. The sheath according to claim 1, wherein the shaft member region exhibits greater flexibility compared to the atraumatic distal end and the proximal end.

18. The sheath according to claim 1, wherein the shaft member region has a lower wall thickness compared to adjacent regions.

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