WO2008142677A2

WO2008142677A2 - Prostate implant and methods for insertion and extraction thereof

Info

Publication number: WO2008142677A2
Application number: PCT/IL2008/000677
Authority: WO
Inventors: Yossi Gross; Eliahu Eliachar; Nir Lilach; Ram Grossfeld; Dan Sade
Original assignee: Prostaplant, Ltd.
Priority date: 2007-05-18
Filing date: 2008-05-18
Publication date: 2008-11-27
Also published as: WO2008142677A3

Abstract

Apparatus is provided, including an implant (120, 1000, 1002, 1202) and a delivery tool (22) removably coupled to the implant (120, 1000, 1002, 1202). The tool (22) is configured to advance the implant (120, 1000, 1002, 1202) distally through a body lumen (60) of a patient until the implant (120, 1000, 1002, 1202) emerges at a distal end of the body lumen (6) into a body cavity (80) of the patient, and subsequently, implant the implant (120, 1000, 1002, 1202) around the body lumen (60) by retracting the implant (120, 1000, 1002, 1202). Other embodiments are also described.

Description

PROSTATE IMPLANT AND METHODS FOR INSERTION AND EXTRACTION

THEREOF

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from US Provisional Patent Application 60/930,705 to Gross et al., entitled, "Prostate implant and methods for insertion and extraction thereof," filed May 18, 2007, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to implants and delivery and extraction tools therefor. Specifically, the present invention relates to an implant that is placed around a body lumen, such as but not limited to, a transurethrally implantable prostatic implant for treatment of benign prostatic hyperplasia (BPH).

BACKGROUND OF THE INVENTION

Benign prostatic hyperplasia (BPH) is a condition wherein a benign (noncancerous) tumor with nodules enlarges the prostate gland. Although the growth is non-cancerous, the internal lobes of the prostate slowly enlarge and progressively occlude the urethral lumen. Severe BPH can cause serious problems over time: Urine retention and strain on the bladder can lead to urinary tract infections, bladder or kidney damage, bladder stones, and incontinence.

US Patent 7,004,965 to Gross, which is incorporated herein by reference, describes an implant system including a transurethral prostatic implant positioned in a prostate and including a lumen with an inner perimeter that surrounds an outer perimeter of a urethra at the prostate. The implant system includes a delivery tool including a shaft having a distal portion and an implant-holding portion proximal to the distal portion, the distal portion being sized for entry into a urethra, and the implant- holding portion being thicker than the distal portion, and an implant positioned on the implant-holding portion.

US Patent 6,991,647 to Jadhav, which is incorporated herein by reference, describes a bio-compatible and bioresorbable stent that is intended to restore or maintain patency following surgical procedures, traumatic injury or stricture formation. The stent composes a blend of at least two polymers that is either extruded as a monofilament then woven into a braid-like embodiment, or injection molded or extruded as a tube with fenestrations in the wall. Methods for manufacturing the stent are also disclosed.

US Patent 7,104,949 to Anderson et al., which is incorporated herein by reference, describes a minimally invasive surgical instrument for placing an implantable article about a tubular tissue structure. The surgical instrument is described as being useful for treating urological disorders such as incontinence. Surgical methods using the novel instrument are also described.

US Patent Application Publication 2004/0181287 to Gellman, which is incorporated herein by reference, describes a stent for treatment of a body lumen through which a flow is effected on either side of a sphincter, said stent comprising one or more windings and having an inner core substantially covered by an outer core and including a first segment, a second segment, and a connecting member disposed between the segments. When the stent is positioned within a patient's urinary system, the first segment and second segments are described as being located on either side of the external sphincter to inhibit migration of the stent while not interfering with the normal functioning of the sphincter. The outer coating is described as comprising an absorbable material that provides temporary structural support to the stent. After absorption of substantially all the outer coating of the stent, the remaining relatively compliant inner core facilitates removal by the patient by pulling a portion of the stent that extends outside the patient's body for this purpose.

SUMMARY OF THE INVENTION

In some embodiments of the present invention, a system for treating urethral constriction at the prostate comprises at least one transurethral Iy implantable prostatic implant and a delivery tool therefor. The delivery tool is advanced into a constricted urethra of a patient. Typically, the implant is removably coupled to the delivery tool at a distal site of the tool. The delivery tool functions to advance the implant distally through the urethra of the patient until the implant emerges at a distal end of the urethra and into a bladder of the patient. (In this context, in the specification and in the claims, "proximal" means closer to the orifice through which the tool is originally placed into the urinary tract, and "distal" means further from this orifice.)

The implant typically comprises a radially-expandable implant, e.g., a coiled implant comprising at least one coil, which is disposed in a compressed state during transurethral advancement thereof. Typically, the implant is compressed between a proximal lock and a distal lock. Once inside the bladder of the patient, the proximal end of the implant is released from the proximal lock by a designated lever controllable from a body of the delivery tool. A distal end of the implant remains fastened to the distal lock during the expansion and subsequent implantation of the implant.

Upon expansion, the implant is shaped to define an implant lumen that is configured to surround an outer circumference of the urethra as the implant is implanted within the prostate. A pointed tip at a proximal end of the implant enables the implant to puncture and penetrate into the prostatic tissue surrounding the urethra of the patient. Rotation of a portion of the delivery tool about a longitudinal axis thereof moves the implant proximally while corkscrewing the implant into the prostatic tissue and thereby around the urethra. Following implantation, the implant radially supports the prostatic tissue and maintains an expanded diameter of the pathologically constricted urethra. Typically, the implant is configured to reside chronically in the prostate of the patient.

In some embodiments, a pointed tip, e.g., a needle, having any shape thereof is soldered to a blunt proximal end of the implant. The scope of the present invention includes attaching the pointed tip using any suitable means of attachment known in the art. In some embodiments, the implant comprises a flexible, biocompatible material, e.g., nitinol, and the pointed tip comprises a rigid, biocompatible material, e.g., stainless steel, configured to facilitate ongoing penetration of the implant as it is advanced through tissue of the patient.

In some embodiments, the implant surface is polished, e.g., electro-polished, mechanically polished, or other, to reduce friction as the implant is advanced through the tissue of the patient.

In some embodiments, the implant is coated with a low-friction coating, e.g., PTFE (Teflon), MoST, ADLC or the like, which reduces friction between the implant's wire surface and the tissue as the implant is advanced through tissue of the patient. In some embodiments, the implant comprises a helical implant comprising a plurality of coils which are helically surrounded by a sheath (i.e., if the helical implant were to be pulled straight, the implant would be relatively-tightly enclosed within the sheath, analogously to a normal insulated wire (the implant) surrounded by a plastic insulator (the sheath)). The sheath is coupled at one end thereof to a tube for passage therethrough of a lubricant into the sheath surrounding the implant. In such an embodiment, the sheath surrounding the coils of the implant is shaped to define holes (e.g., toward the proximal end of the implant), for release of the lubricant externally to the implant. The lubricant, in turn, reduces the frictional force between the tissue and the implant. In some embodiments, the helical implant itself is a hollow, helical implant defining a helical lumen therein. Typically, the lumen is configured for passage of a fluid therethrough. The hollow, helical implant is shaped to define holes (e.g., typically toward the proximal end of the implant) for release of the fluid externally to the implant. In some embodiments, the fluid comprises a lubricant which passes externally to the implant via the holes defined thereby in order to reduce a frictional force between the tissue and the implant.

In some embodiments, the hollow, helical implant is shaped to define at least one hole, e.g., a plurality of holes, at the proximal end thereof. In such an embodiment, the fluid may comprise saline which is injected at high pressure through the lumen of the hollow, helical implant and externally to the implant via the at least one hole in order to cut tissue near the proximal tip of the implant as it advances through the tissue.

In some embodiments, the hollow, helical lumen is configured for passage therethrough of a laser fiber to ablate tissue in the path of the implant as it is advanced therethrough. In some embodiments, an insulated RF transmitting wire having a non- insulated transmitting tip is slidably advanced through the helical lumen of the hollow implant.

In some embodiments, the proximal end of the implant ablates the tissue as the implant is advanced through the tissue of the patient. In such an embodiment, the implant may be coated with a substance, such as but not limited to, a medication (e.g., an antibiotic) or with an electrical insulator (e.g., Teflon). A portion of the proximal end of the implant, i.e., one or more of the coils, may be energized to deliver RF energy, for example, to ablate the tissue. In some embodiments, the portion of the proximal end of the implant is coupled to a separate electrode. Additionally or alternatively, the portion of the proximal end of the implant may be energized to provide ultrasound or thermal energy (e.g., heating or cooling).

In some embodiments of the present invention, the at least one implant comprises two or more coiled implants which, when implanted within the tissue, are configured to be disposed in a relative spatial configuration in which the implants are coaxially disposed and rotationally offset by a given angle with respect to each other. Additionally, when positioned in the relative spatial configuration, at least a portion of each of the implants overlap longitudinally. Typically, the implants longitudinally essentially entirely overlap each other.

In some embodiments, a first coiled implant may be rotationally offset 180 degrees (by way of illustration and not limitation) with respect to a second coiled implant. Alternatively, three coiled implants are coaxially disposed and rotationally offset 120 degrees (by way of illustration and not limitation) with respect to each other.

In some embodiments, the two or more coiled implants are implanted at the same time into tissue of the patient. For embodiments in which two coiled implants are rotationally offset 180 degrees with respect to each other: a proximal end of the first coiled implant enters the tissue at a first location thereof, and a proximal end of the second coiled implant enters the tissue 180 degrees from the first location. In some embodiments, the first and second coiled implants are implanted sequentially. The first coiled implant punctures the tissue at a first location and is fully advanced into the tissue by the delivery system. Once the first coiled implant is implanted, the delivery system is removed from the patient, is coupled to the second coiled implant, and is reintroduced within the lumen of the body of the patient. The second coiled implant is advanced into the body cavity of the patient, expands within the cavity, and punctures the tissue at a second location which is rotationally offset 180 degrees from the first location. The second coiled implant is corkscrewed into the tissue coaxially with respect to a position of the implanted first coiled implant. The second coiled implant is advanced fully through the tissue until it is disposed coaxially and is rotationally offset by 180 degrees with respect to the first coiled implant.

Typically, once the two or more coiled implants are implanted in the tissue, the two or more implants are coaxially disposed such that a respective longitudinal position of the coiled implants overlap, at least in part. Typically, a pitch of each coiled implant is directly proportional to the number of coiled implants configured to be coaxially disposed when implanted in tissue of the patient. For example, when one coiled implant is implanted in the tissue, the coiled implant may have a length of 3-5 cm and a pitch of approximately 3-9 mm. When first and second coiled implants are configured to be coaxially disposed and rotationally offset 180 degrees with respect to each other (e.g., when implanted in tissue), each coiled implant has a length of 3-5 cm and a pitch of approximately 6-18 mm, such that when the respective longitudinal positions of the implants are overlapped, and the implants are coupled together by being coaxially disposed, the effective average pitch between adjacent coils of the coaxially disposed first and second coiled implants is approximately 3-9 mm.

Typically, the frictional force of the tissue on the coiled implant is inversely related to the pitch and the length of a coil implanted. That is, a small-pitch coiled implant has an along-the-coil length, i.e., the length of the wire when the coil is straightened, that is larger than an along-the-coil length of a high-pitch coiled implant. Thus, the overall frictional force applied to a small-pitch coiled implant is larger than the overall frictional force applied to a large-pitch coiled implant, because the frictional force applied to the small-pitch coiled implant is applied along a larger coil length. Thus, as each of the first and second coiled implants is implanted within tissue of the patient, e.g., simultaneously or sequentially, the force needed in order to overcome the frictional force applied to each coiled implant is smaller in comparison to the force applied to a coiled implant having a pitch similar to the average pitch of the combined first and second coiled implants.

Additionally, the higher-pitch implant is characterized as being stronger and more rigid in comparison to the small-pitch coiled implants.

In some embodiments of the present invention, the implant comprises a coiled implant having a generally conic shape, in which the proximal coil of the coiled implant has a diameter that is larger than the diameter of the distal coil. In such an embodiment, as the proximal coils are advanced through the tissue, the tissue applies a frictional force on the proximal coils of the coiled implant. In an attempt to corkscrew into the tissue the distal coils of the coiled implant, the tissue exerts a slightly larger frictional force on the distal coils of the coiled implant. In response to the frictional force applied to the distal coils as they are corkscrewed into the tissue, the distal coils expand radially such that the respective diameters of the distal coils become closer to the respective diameters of the proximal coils.

Typically, the implantation procedure is monitored by an imaging element, e.g., a flexible cystoscope, which is introduced through the lumen of the delivery tool. Alternatively or additionally, an optical sensor, e.g., CCD, CIS, or CMOS, is coupled to a distal portion of the delivery tool. In some embodiments of the present invention, apparatus enables extraction of the implant from the prostatic tissue. Typically, the implant comprises a flexible, shape-memory composite, e.g., nitinol, which is configured to assume a predefined shape in tissue, e.g., a coil. During extraction of the implant from the prostate, the implant is first retracted into the bladder of the patient. The implant is then captured by a clamp or by forceps, and due to the flexibility of the composite, the implant is made to assume an elongated, straight configuration as it is pulled through a designated straight tube. Such conforming ability enables atraumatic extraction thereof from the bladder.

Typically, the extraction tool comprises at least one mechanically adjustable clamp which engages a portion of the implant during the extraction procedure. Typically, the portion includes the distal end of the implant which resides within the bladder neck tissue. An optical guide, e.g., a CCD, CIS, or CMOS sensor or an optical fiber-based system, guides the engaging and subsequent extraction of the implant. The extraction process is two-fold:

(a) The clamp engages a distal end of the implant. The clamp is then rotated helically around a longitudinal axis of the tool and of the urethra, thereby unscrewing and extracting the implant distally into the bladder from the prostate. In order to extract/unscrew the implant from the prostate, the implant is rotated and moved distally by counter-rotation (with respect to the direction of rotation during the implantation procedure); and (b) following extraction of the implant from the prostate, the extraction clamp detaches from the distal end of the implant, allowing the implant to slide distally off the tool until it lies against the lower wall of the bladder. The clamp then engages either the proximal or the distal end of the coiled implant. The engaged end of the coiled implant is then pulled in a proximal direction through an outer sheath surrounding the lumen of the extraction tool. Due to its elasticity, the implant assumes an elongated, straight configuration as it is pulled through the outer sheath.

In some embodiments, two clamps are used in order to extract the implant from the bladder of the subject. A distal clamp typically extracts the implant from the prostate. Subsequent to the extraction, a proximal clamp is advanced into the bladder of the patient and engages the proximal end of the implant. The proximal clamp is used to pull the implant through the outer sheath as the distal clamp remains at a fixed distance within the bladder of the patient. Such configuration of the distal clamp with respect to the proximal clamp enhances stability of the extraction procedure by maintaining the distal end of the implant within the bladder as the proximal end is being pulled by the proximal clamp into a straight configuration and ultimately outside the body of the patient. There is therefore provided, in accordance with an embodiment of the present invention apparatus, including: an implant; and a delivery tool, removably coupled to the implant, the tool configured to: advance the implant distally through a body lumen of a patient until the implant emerges at a distal end of the body lumen into a body cavity of the patient, and subsequently, implant the implant around the body lumen by retracting the implant. In an embodiment, the implant includes a low-friction coating.

In an embodiment, a surface of the implant includes a polished surface configured to reduce friction of the implant during implantation.

In an embodiment, the implant is radially-expandable, and configured to expand upon emergence into the body cavity. In an embodiment, the body lumen includes a urethra, and the implant is configured to be implanted around the urethra.

In an embodiment, the implant includes a transurethral ly-implantable prostatic implant configured to be positionable in a prostate of the patient, and the body lumen includes a urethra of the patient, the implant being shaped to define an implant lumen that surrounds an outer circumference of the urethra upon implantation.

In an embodiment, the implant is shaped to define an implant lumen that surrounds an outer circumference of the lumen upon implantation.

In an embodiment, the implant is shaped to define an inner diameter of at least 2.5 mm. In an embodiment, the implant is shaped to define an inner diameter of between

2.5 mm and 15 mm.

In an embodiment, the implant is configured to prevent restenosis of the body lumen.

In an embodiment, the delivery tool is shaped to define a delivery tool lumen for passing an imaging device therethrough. In an embodiment, the apparatus includes an imaging device configured to guide the retraction of the implant.

In an embodiment, the delivery tool includes a rotating element configured to corkscrew the implant into the tissue during the retracting of the implant. In an embodiment, the delivery tool includes a rotating element configured to corkscrew the implant into the tissue by rotation about a longitudinal axis of the delivery tool.

In an embodiment, the implant includes a flexible, biocompatible material selected from the group consisting of: nitinol and silicone. In an embodiment, the apparatus includes a needle coupled to a proximal end of the implant.

In an embodiment, the needle includes a rigid, biocompatible material configured to puncture tissue of the patient.

In an embodiment, the needle includes stainless steel. In an embodiment, the implant includes a coiled implant including at least one coil.

In an embodiment, the coiled implant is configured to corkscrew into a prostate of the patient.

In an embodiment, the coil includes a conically-shaped coiled implant. In an embodiment, a proximal coil of the conically-shaped coiled implant has a diameter that is larger than a diameter of a distal coil of the conically-shaped coiled implant.

In an embodiment, the coiled implant is configured to corkscrew into tissue of the patient. In an embodiment, the coiled implant is shaped to define a proximal pointed end configured to puncture the tissue.

In an embodiment, the delivery tool is configured to implant the implant around the body lumen by corkscrewing the coiled implant into the tissue while retracting the implant. In an embodiment, the tissue includes a prostate of the patient, and the delivery tool is configured to corkscrew the coiled implant into the prostate.

In an embodiment, the implant is shaped to define at least one slit configured for engaging of the delivery tool thereto. In an embodiment, the implant includes a coiled implant.

In an embodiment, the implant is shaped to provide a proximal slit and a distal slit.

In an embodiment, the delivery tool includes a proximal locking mechanism and a distal locking mechanism, the proximal locking mechanism is configured to engage the proximal slit of the implant, and the distal locking mechanism is configured to engage the distal slit of the implant.

In an embodiment, the proximal and distal locking mechanisms are configured to maintain the implant in a compressed state thereof during the advancement of the implant into the body cavity of the patient. In an embodiment, the implant is configured to expand radially following a disengagement of the proximal locking mechanism therefrom.

In an embodiment, the implant is shaped to define a helical implant, and the apparatus includes a sheath shaped to define a hollow lumen helically surrounding the helical implant. In an embodiment, the apparatus includes an ablation tool configured to be slidably advanced through the lumen of the sheath, and the sheath is shaped to define at least one hole at a proximal end thereof configured for advancement therethrough of at least a portion of the ablation tool.

In an embodiment, the apparatus includes a flexible tube coupled to a portion of the sheath, the tube being configured to facilitate passage of a fluid through the lumen of the sheath, and the sheath is shaped to define one or more holes configured for passage of the fluid externally to the implant.

In an embodiment, the implant includes a hollow, helical implant shaped to define a helical lumen thereof. In an embodiment, the apparatus includes an ablation tool configured to be slidably advanced through the lumen of the implant, and the implant is shaped to define at least one hole at a proximal end thereof configured for advancement therethrough of at least a portion of the ablation tool. In an embodiment, the apparatus includes a flexible tube coupled to a portion of the helical implant, the tube being configured to facilitate passage of a fluid through the lumen of the implant, and the implant is shaped to define one or more holes configured for passage of the fluid externally to the implant.

In an embodiment, the implant includes at least first and second implants. In an embodiment, the implant includes at least first and second helical implants.

In an embodiment, the at least first and second helical implants are configured to assume respective longitudinal positions and are configured to be disposed in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part.

In an embodiment, the first and second implants have the same diameter. In an embodiment, the first and second helical implants each have a first pitch, and, when disposed in the relative spatial configuration, the first and second implants define an effective second pitch which is less than half the first pitch.

In an embodiment, the delivery tool is configured to implant the first and second helical implants sequentially and position the first and second helical implants in the relative spatial configuration thereof.

In an embodiment, the first and second helical implants are configured to be coupled to the delivery tool in the relative spatial configuration.

In an embodiment, the first and second helical implants are configured to be simultaneously implanted around the body lumen of the patient. In an embodiment, the at least first and second helical implants include respective transurethrally-implantable prostatic implants configured to be positionable in a prostate of the patient, and the body lumen includes a urethra of the patient, the first and second implants being shaped to define respective implant lumens that surrounds an outer circumference of the urethra upon implantation.

In an embodiment, the first and second helical implants are shaped to define respective proximal pointed ends configured to puncture the tissue.

There is further provided, in accordance with an embodiment of the present invention, a method, including: distally advancing an implant through a body lumen of a patient until the implant emerges in a body cavity of the patient; and implanting the implant in tissue surrounding the body lumen by proximally retracting the implant.

In an embodiment, the implant includes a radially-expandable implant, and advancing the implant into the body cavity includes facilitating the expansion of the implant within the body cavity of the patient.

In an embodiment, the implant includes a conically-shaped coiled implant in which a diameter of a proximal coil thereof is larger than a diameter of a distal coil thereof, and implanting the implant includes implanting the conically-shaped coiled implant in the tissue of the patient.

In an embodiment, the body lumen includes a urethra and implanting the implant includes implanting the implant around the urethra.

In an embodiment, implanting the implant includes implanting the implant in a prostate of the patient. In an embodiment, the method includes reversibly coupling the implant to a delivery tool, advancing the implant includes advancing the delivery tool, when it is reversibly coupled to the implant, through the body lumen of the patient.

In an embodiment, implanting the implant includes decoupling the implant from the delivery tool. In an embodiment, proximally retracting the implant includes corkscrewing the implant into the tissue by rotating at least a portion of the delivery tool.

In an embodiment, the tissue surrounding the body lumen includes a prostate of the patient, and implanting the implant includes corkscrewing the implant into the prostate by rotating at least a portion of the delivery tool.

In an embodiment, the method includes imaging via an imaging device coupled to the delivery tool.

In an embodiment, imaging includes examining a bladder of the patient via the imaging device, prior to the advancing of the implant through the body lumen, by imaging a vicinity of a neck of the bladder of the patient.

In an embodiment, imaging includes imaging the implanting of the implant in the tissue surrounding the body lumen of the patient.

In an embodiment, distally advancing the implant includes distally advancing at least first and second implants through the body lumen of the patient, and implanting the implant includes implanting the at least first and second implants in tissue surrounding the body lumen.

In an embodiment, implanting the at least first and second implants in tissue surrounding the body lumen implant includes corkscrewing the first and second implant into the prostate by rotating at least a portion of the delivery tool. In an embodiment, the tissue surrounding the body lumen includes a prostate of the patient, and implanting the first and second implants includes corkscrewing the first and second implants into the prostate by rotating at least a portion of the delivery tool.

In an embodiment, the method includes: reversibly coupling the first implant to a delivery tool; and reversibly coupling the second implant to the delivery tool, and advancing the first and second implants includes advancing the first and second implants through the body lumen of the patient by the delivery tool.

In an embodiment, implanting the first and second implants includes decoupling the first and second implants from the delivery tool. In an embodiment, proximally retracting the implant includes corkscrewing the first and second implants into the tissue by rotating at least a portion of the delivery tool.

In an embodiment, implanting the first and second implants includes implanting first and second implants in respective longitudinal positions thereof in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part.

In an embodiment, reversibly coupling the first and second implants to the delivery tool includes reversibly coupling to the delivery tool the first and second implants in the relative spatial configuration thereof, and advancing the first and second implants includes simultaneously advancing the first and second implants through the body lumen of the patient.

In an embodiment, implanting the first and second implants in the relative spatial configuration thereof includes: during a first period: reversibly coupling the first implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the first implant, through the body lumen of the patient, and implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant through a first opening created by the first implant, and during a second period subsequent to the first period: reversibly coupling the second implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the second implant, through the body lumen of the patient, and implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant through a second opening created by the second implant, the second opening is rotationally offset from the first opening with respect to a longitudinal axis of the body lumen. There is additionally provided, in accordance with an embodiment of the present invention, a method, including: at a first time, implanting an implant around a lumen of a patient by: advancing the implant distally through the lumen until the implant emerges at a distal end of the lumen into a cavity, and subsequently, implanting the implant around the lumen by proximal Iy retracting the implant; and at a second time, extracting the implant from around the lumen by: moving the implant distally by rotating the implant, and subsequently, pulling the implant proximally through the lumen.

In an embodiment, implanting the implant around the lumen includes rotating the implant in a first direction thereof, and extracting the implant includes rotating the implant in a reverse direction to the first direction.

In an embodiment, the implant includes a radially-expandable implant, and advancing the implant includes allowing the expansion of the implant within the cavity.

In an embodiment, extracting the implant includes: clamping a distal portion of the implant and moving the implant distally by rotating the implant; and clamping a proximal portion of the implant.

In an embodiment, the lumen includes a urethra of the patient and pulling the implant includes pulling the implant through the urethra.

In an embodiment, rotating the implant includes extracting the implant from a prostate of the patient.

There is yet further provided, in accordance with an embodiment of the present invention, apparatus, including: at least first and second helical implants configured to assume respective longitudinal positions and to be disposed in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part; and a delivery tool, configured to be reversibly coupled to the at least first and second helical implants, the tool configured to: advance the at least first and second implants distally through a body lumen of a patient until the first and second implants emerge at a distal end of the body lumen into a body cavity of the patient, and implant the at least first and second implants in the relative spatial configuration thereof around the body lumen by retracting the first and second implants.

In an embodiment, the first and second implants have the same diameter.

In an embodiment, the first and second implants includes low-friction coatings.

In an embodiment, the first and second implants are radially expandable, and configured to expand upon emergence into the body cavity. In an embodiment, the body lumen includes a urethra, and the first and second implants are configured to be implanted around the urethra.

In an embodiment, the first and second implants include respective transurethrally-implantable prostatic implants configured to be positionable in a prostate of the patient, and the body lumen includes a urethra of the patient, the implants being shaped to define respective implant lumens that surround an outer circumference of the urethra upon implantation.

In an embodiment, the first and second implants are shaped to define respective implant lumens that surround an outer circumference of the lumen upon implantation.

In an embodiment, the first and second implants are shaped to define respective inner diameters of at least 2.5 mm.

In an embodiment, the first and second implants are shaped to define respective inner diameters of between 2.5 mm and 15 mm.

In an embodiment, the first and second helical implants each have a first pitch, and, when disposed in the relative spatial configuration, the first and second implants define an effective second pitch which is less than half the first pitch. In an embodiment, the delivery tool is configured to implant the first and second helical implants sequentially and position the first and second helical implants in the relative spatial configuration thereof.

In an embodiment, the first and second helical implants are configured to be simultaneously implanted around the body lumen of the patient.

There is still further provided, in accordance with an embodiment of the present invention, a method, including: creating a first opening in tissue of a patient by puncturing the tissue; advancing through the first opening a first helical implant to a first longitudinal position; creating a second opening in tissue of the patient by puncturing the tissue, the second opening being rotationally offset from the first opening with respect to a longitudinal axis of the first helical implant when it has been advanced through the first opening; and advancing through the second opening a second helical implant to a second longitudinal position, in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset with respect to each other, and respective longitudinal positions of the first and second helical implants overlap at least in part.

In an embodiment, advancing through the first opening the first helical implant to the first longitudinal position includes corkscrewing the first helical implant into the tissue, and advancing through the second opening the second helical implant to the second longitudinal position includes corkscrewing the second helical implant into the tissue. In an embodiment, the tissue includes a prostate of the patient, and advancing the first and second helical implants includes corkscrewing the first and second helical implants into the prostate.

In an embodiment, the method includes: distally advancing the first and second helical implants through a body lumen of a patient until the first and second implants emerge in a body cavity of the patient, and: advancing through the first opening the first helical implant to the first longitudinal position includes implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant, and advancing through the second opening the second helical implant to the second longitudinal position includes implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant.

In an embodiment, the method includes: reversibly coupling the first implant to a delivery tool; and reversibly coupling the second implant to the delivery tool, and distally advancing the first and second implants includes distally advancing the first and second implants through the body lumen of the patient by the delivery tool.

In an embodiment, implanting the first and second implants includes decoupling the first and second implants from the delivery tool.

In an embodiment, proximally retracting the implants includes corkscrewing the first and second implants into the tissue by rotating at least a portion of the delivery tool.

In an embodiment, implanting the first and second implants in the relative spatial configuration thereof includes: during a first period: reversibly coupling the first implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the first implant, through the body lumen of the patient, and implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant through a first opening created by the first implant, and during a second period subsequent to the first period: reversibly coupling the second implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the second implant, through the body lumen of the patient, and implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant through a second opening created by the second implant, the second opening is rotationally offset from the first opening with respect to a longitudinal axis of the body lumen.

There is yet additionally provided, in accordance with an embodiment of the present invention, apparatus, including: a helical implant; and a sheath, helically surrounding the implant, the sheath shaped to define one or more holes. In an embodiment, the sheath is shaped to define three or more holes.

In an embodiment, the helical implant is shaped to define an inner diameter thereof that is between 2.5 mm and 15 mm.

In an embodiment, the sheath tightly surrounds the helical implant.

In an embodiment, the apparatus includes: a lubricant; and a pressure source configured to push the lubricant (a) from within a space between the helical implant and the sheath, (b) through the one or more holes, (c) to outside of the sheath. There is also provided, in accordance with an embodiment of the present invention, apparatus, including: a helical implant having a wall shaped to define a plurality of holes, the helical implant shaped to define a helical lumen thereof; a lubricant, disposed within the lumen; and a pressure source, configured to push the lubricant through the plurality of holes.

In an embodiment, the pressure source includes a syringe.

The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic illustration of a delivery tool being introduced within a constricted urethra of a patient, in accordance with an embodiment of the present invention;

Fig. 2 is a schematic illustration of an implant disposed in a compressed state at a distal end of the delivery tool of Fig. 1, in accordance with an embodiment of the present invention;

Figs. 3 and 4 are schematic illustrations of the implant of Fig. 2 expanding once inside a bladder of the patient, in accordance with an embodiment of the present invention;

Fig. 5 is a schematic illustration of the implant of Fig. 2 being implanted around the urethra in a prostate of the patient, in accordance with an embodiment of the present invention;

Fig. 6 is a schematic illustration of the implant of Fig. 2 implanted within the prostate of the patient, in accordance with an embodiment of the present invention;

Fig. 7 is a schematic illustration of an extraction tool being advanced into the bladder of the patient, in accordance with an embodiment of the present invention; Fig. 8 is a schematic illustration of the extraction tool removing the implant from the prostate of the patient, in accordance with an embodiment of the present invention;

Fig. 9 is a schematic illustration of the implant being extracted from the body of the patient, in accordance with an embodiment of the present invention;

Fig. 10 is a schematic illustration of the delivery tool coupled to first and second coiled implants, in accordance with an embodiment of the present invention;

Fig. 1 1 is a schematic illustration of the delivery tool coupled to a conic coiled implant, in accordance with an embodiment of the present invention; and Fig. 12 is a schematic illustration of an implant configured to be implanted around a body lumen of the patient, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference is made to Fig. 1, which is a schematic illustration of a system 20 comprising a delivery tool 22 being introduced into a urethra 60 of a patient, in accordance with an embodiment of the present invention. Urethra 60 is constricted due to pressure exerted thereupon by a prostate 100 of the patient. Stenosis of urethra 60 by prostate 100 defines a diameter Dl at a bladder neck 64 of the patient and along a portion of urethra 60 surrounded by prostate 100. Untreated stenosis of urethra 60 by prostate 100 often engenders acute urinary retention by bladder 80 of the patient, thus causing infrequent urination and ultimately, incontinence. An outer sheath 24 is advanced distally through a proximal end 62 of urethra 60 and toward bladder neck 64 of the patient. Outer sheath 24 expands urethra 60 as sheath 24 is distally advanced toward bladder 80 of the patient. Typically, outer sheath 24 is advanced via an introducer tube (not shown) having a rounded proximal end which facilitates atraumatic advancement of outer sheath 24 through urethra 60. Outer sheath 24 is advanced along urethra 60 prior to the advancement of delivery tool shaft 25, thus creating an open passageway for the subsequent insertion of delivery tool 22. Typically, outer sheath 24 is hollow and enables passage of tools through the urethra by providing a working channel of sheath 24. An imaging device (not shown), e.g., a fiberscope or a cystoscope, is advanced through outer sheath 24 into bladder 80. Bladder 80 and bladder neck 64 are examined prior to the introduction of delivery tool 22 into urethra 60 of the patient. The imaging device is typically flexible and bends 180 degrees in a proximal direction, facilitating visualization of a vicinity of bladder neck 64 of the patient.

Delivery tool 22 comprises a body 21 and a delivery tool shaft 25 which is advanced distally through outer sheath 24 toward bladder 80 of the patient. Typically, shaft 25 comprises a hollow lumen for passing substances and/or tools therethrough, such as but not limited to, medications, fiber optics, biopsy tools, optical devices (e.g.,

CCD) and/or other imaging devices.

Reference is now made to Fig. 2, which is a schematic illustration of system 20 comprising a transurethral Iy implantable prostatic implant 120, which surrounds a distal end of shaft 25 of delivery tool 22, in accordance with an embodiment of the present invention. Typically, implant 120 comprises a radially-expandable implant, e.g., a coil. Implant 120 typically comprises a flexible biocompatible material, e.g., nitinol or silicone.

During transurethral advancement, implant 120 is disposed in a compressed state thereof between a proximal implant holder 124 and a distal implant holder 54.

Typically, a distal end 126 and a proximal end 122 of implant 120 are each shaped to define a slit (134 and 132, respectively). Each slit is configured for passage of respective fastening devices therethrough. The fastening devices maintain the compressed state of implant 120 during advancement thereof into bladder 80 of the patient.

Proximal implant holder 124 is shaped to provide a latitudinal groove 125 for holding and securing proximal end 122 of implant 120. Additionally, proximal implant holder 124 is shaped to provide a longitudinal slit for advancement of a first elongate mechanical fastener 127 therethrough and subsequently through slit 132 of proximal end 122 of implant 120. Fastener 127 is advanced (a) through the longitudinal slit within holder 124, (b) subsequently through slit 132 of proximal end 122 of implant 120, and (c) back into a slit at a portion of holder 124 distal to groove 125.

Distal implant holder 54 comprises a similar securing mechanism as holder 124. Distal implant holder 54 is shaped to provide a latitudinal groove 56 at a proximal end thereof which holds and secures distal end 126 of implant 120 in a compressed state during advancement thereof. Additionally, distal implant holder 54 maintains coupling of implant 120 to tool 22 during implantation of implant 120. A second elongate mechanical fastener 129 is advanced (a) through a longitudinal slit within distal implant holder 54, (b) subsequently through slit 134 of distal end 126 of implant 120, and (c) back into a slit at a portion of distal implant holder 54 proximal to groove 56.

The securing and releasing of fasteners 127 and 129 are controlled remotely, by body 21 of delivery tool 22. Fig. 3 shows implant 120 expanding from a compressed state thereof, in accordance with an embodiment of the present invention. The distal-most end of sheath 24 is disposed distally to bladder neck 64, facilitating proper placement within bladder 80 of any device passed through sheath 24, e.g., implant 120. Typically, outer sheath 24 is shaped to define a length which is shorter than a length of delivery tool shaft 25. Thus, once shaft 25 has been fully advanced through sheath 24, proximal end 122 of implant 120 is disposed distally with respect to the distal-most end of sheath 24. When proximal end 122 of implant 120 has sufficiently entered bladder 80 of the patient (e.g., as shown), proximal end 122 is released from proximal implant holder 124, allowing implant 120 to assume an expanded configuration.

Reference is again made to Fig. 1. Delivery tool 22 comprises a rotating element 30 at a proximal end thereof which is configured to facilitate implantation of implant 120 once the implant is inside bladder 80 of the patient. During the distal advancing of delivery tool shaft 25 toward bladder 80 of the patient, rotating element

30 is disposed adjacent to body 21 of tool 22, as shown.

Body 21 comprises one or more control elements 28 on a surface of tool 22 which enables a physician to control, from outside of the patient's body, one or more functional elements located at the distal end of delivery tool 22. Typically, but not necessarily, control elements 28 comprise rings for the physician to engage her fingers therethrough and push or pull on control elements 28. During advancement of delivery tool 22 within sheath 24, elements 28 are disposed in a distal orientation with respect to delivery tool 22, e.g., at the distal end of a slot 130 in delivery tool 22 (configuration not shown).

As shown in Fig. 3, once the distal end of delivery tool shaft 25 enters bladder 80, implant 120 is further pushed distally by pushing on a switch 42 disposed at a proximal end of body 21 of tool 22. Such pushing further facilitates that proximal end 122 of implant 120 is disposed distal to bladder neck 64 prior to implantation of implant 120 therearound. Control elements 28 are then pulled proximally with respect to delivery tool 22. Control elements 28 are coupled to a proximal end of fastener 127. In response to the pulling, a distal end of fastener 127 is pulled to a position that is proximal to proximal end 122 of implant 120, thereby releasing proximal end 122 of implant 120 and effecting radial expansion thereof. Fig. 3 shows system 20 immediately after control elements 28 have reached their proximal-most extent, decoupling fastener 127 from implant 120, but prior to the resultant radial expansion of the implant. During expansion of implant 120, distal end 126 of implant 120 remains coupled to distal implant holder 54.

To minimize the chance of physician error, tool 22 may comprise a distal lock

32, a proximal lock 34, and a release 36. Pulling and pushing of control elements 28 is restricted by locks 32 and 34. For example, when elements 28 are disposed distally with respect to tool 22, distal lock 32 automatically maintains the distal position of elements 28 such that elements 28 are not inadvertently pulled (resulting in premature expansion of implant 120 during advancement thereof). When proximal motion of control elements 28 is desired, the physician activates release 36, to release lock 32, allowing for such proximal motion of elements 28. Once disposed proximally with respect to tool 22, proximal lock 34 secures elements 28 in place, typically automatically.

Reference is now made to Fig. 4, which is a schematic illustration of system 20 comprising expandable guiding elements 26, in accordance with an embodiment of the present invention.

Reference is now made to Figs. 3 and 4. As shown in Fig. 3, during advancement of tool 22 through outer sheath 24, distal implant holder 54 is disposed in a configuration such that a distal portion thereof covers a lumen of shaft 25 of delivery tool 22. Switch 42 is oriented in a downward configuration indicative of the closed configuration of distal implant holder 54. As shown in Fig. 4, manually rotating switch 42 in an upward configuration, e.g., 180 degrees, rotates distal implant holder 54, thereby exposing the lumen of delivery tool shaft 25. Additionally, rotation of distal implant holder 54 positions implant 120 coaxially with respect to the urethra, such that implant 120 is properly corkscrewed symmetrically around the urethra. Imaging device 70 is then advanced through the lumen of shaft 25, and guides the subsequent implantation of implant 120. Imaging device 70 is configured to bend 180 degrees and rotate 360 degrees in order to image the implantation procedure.

Reference is now made to Figs. 2 and 4. As shown in Fig. 2, expandable guiding elements 26 surround a portion of delivery tool shaft 25 proximal to implant 120. Distal and proximal ends of expandable elements 26 are each coupled to a first ring 27 and a second ring 29, respectively. Typically, first ring 27 is fixed to a portion of shaft 25 while second ring 29 is configured to slide distally and proximally along shaft 25. Alternatively, first ring 27 is configured to slide distally until a stopping element impedes continued distal motion of ring 27. Such distal motion of ring 27 facilitates positioning of ring 27 and distal portions of guiding elements 26 within the lumen of the implant prior to expansion of elements 26. During the advancing of delivery tool shaft 25 toward bladder 80, guiding elements 26 are typically pressed against the outer surface of shaft 25.

Fig. 4 shows deployment of expandable guiding elements 26 following expansion of implant 120. Distal pushing of control elements 28 slides ring 29 distally toward ring 27. The distal and proximal ends of expandable elements 26 are drawn toward one another, resulting in the radial expansion of expandable elements 26. Expandable guiding elements 26 expand such that they align with an inner surface of implant 120. Such alignment facilitates the guiding of implant 120 and the maintenance of a straight configuration thereof during the implantation procedure. Typically, once implant 120 is fully disposed within bladder 80, body 21 of tool 22 is disposed adjacent to a proximal-most end of sheath 24. The implantation of implant 120 within prostate 100 begins when the physician distances body 21 from outer sheath 24, thereby shifting tool 22 proximally. Such shifting positions proximal end 122 of implant 120 in proximity with bladder neck 64 immediately prior to implantation of implant 120.

Reference is now made to Fig. 5, which is a schematic illustration of implant

120 of system 20 being partially implanted in prostate 100 of the patient, in accordance with an embodiment of the present invention. Upon expansion within bladder 80 of the patient, implant 120 is shaped to define an inner lumen diameter, e.g., 2.5 mm to 15 mm, typically larger than the non-constricted outer diameter of urethra 60.

Proximal end 122 of implant 120 is typically pointed and is configured to puncture tissue of prostate 100. In some embodiments, proximal end 122 is coupled to, e.g., soldered to or attached using any other applicable attachment means, a pointed needle which is configured to puncture tissue of the patient. Typically, the needle coupled to proximal end 122 comprises a rigid, biocompatible material, e.g., stainless steel, configured to configured to facilitate ongoing penetration of the implant as it is advanced through tissue of prostate 100. It is to be noted that the needle is shaped to define any suitable shape configured for cutting/penetrating tissue.

Following the puncturing of the tissue by proximal end 122 or, in some embodiments, the needle coupled thereto, implant 120 is further advanced proximally in the tissue of prostate 100, around urethra 60 of the patient. Counterclockwise rotation of rotating element 30 rotates and proximally retracts implant 120, thus corkscrewing implant 120 within tissue of prostate 100 surrounding urethra 60. Positioning of implant 120 within tissue of prostate 100 is typically guided by imaging element 70. In some embodiments, as proximal end 122 (or a needle coupled thereto) of implant 120 is advanced through the tissue of the patient, it is configured to ablate the tissue. In such an embodiment, implant 120 may be coated with a substance, such as but not limited to, a medication (e.g., an antibiotic) or with an electrical insulator (e.g., Teflon). A portion of proximal end 122 of implant 120, i.e., one or more of the coils, may be energized to deliver RF energy, for example, to ablate tissue. In some embodiments, the portion of proximal end 122 of implant 120 is coupled to an electrode. Additionally or alternatively, the portion of proximal end 122 of implant 120 may be energized to provide ultrasound or thermal energy (e.g., heating or cooling). In some embodiments, the implant 120 comprises a hollow, helical implant shaped to define a helical lumen and at least one hole, e.g., a plurality of holes, at the proximal end thereof. In such an embodiment, a fluid, e.g., saline, is injected at high pressure through the lumen of the hollow, helical implant and externally to the implant via the at least one hole in order to cut tissue near the proximal tip of the implant as it advances through the tissue.

In some embodiments, the hollow, helical implant is configured for passage through its lumen and through the hole at the proximal end thereof, of a laser fiber to ablate tissue in the path of the implant as it is advanced therethrough. In some embodiments, an insulated RF transmitting wire (i.e., having a non-insulated transmitting-tip) is advanced through the helical lumen of the hollow implant. In some embodiments, the hollow, helical implant is configured for passage through its lumen of a fluid (configuration described hereinbelow with reference to Fig. 12). The hollow, helical implant is shaped to define holes (e.g., typically toward the proximal end of the implant) for release of the fluid externally to the implant. In some embodiments, the fluid comprises a lubricant which passes externally to the implant via the holes defined thereby in order to reduce a frictional force between the tissue and the implant.

Expandable guiding elements 26 guide the initial - implantation (e.g., longitudinal motion of 6 mm to 1 1 mm in a proximal direction) of proximal end 122 of implant 120 around urethra 60. Control elements 28 are then pulled proximally, thereby sliding ring 29 proximally such that guiding elements 26 are pressed once again against the outer surface of shaft 25 (alignment shown in Fig. 2). As shown in Fig. 5, control elements 28 are disposed in a proximal orientation with respect to body 21 of delivery tool 22 indicating a retracted state of guiding elements 26. Clockwise rotation of rotating element 30 retracts shaft 25, thereby retracting distal implant holder 54 attached to distal portion 126 of implant 120. In response to the retracting, distal implant holder 54 helps corkscrew implant 120 into tissue of prostate 100 by applying to implant 120 a force in the proximal direction. During the clockwise rotation, rotating element 30 is distanced from body 21 of delivery tool 22 by a distance Ll. Ll is typically smaller than a maximal distance between rotating element 30 and body 21 of tool 22, thus indicating partial implantation of implant 120 around urethra 60 of the patient.

Following initial partial implantation of implant 120 and alignment of expandable guiding elements 26 along shaft 25, implant 120 is further advanced proximally through prostate 100, around urethra 60 of the patient. Once implant 120 is fully implanted in prostate 100, distal end 126 is decoupled from distal implant holder 54 by retracting fastener 129 from slit 134 at distal end 126 of implant 120. Fastener 129 is controlled by a control element 40, which is disposed at a proximal end of body 21 of delivery tool 22. Pulling on element 40 retracts fastener 129 from slit 134, thereby releasing implant 120 from holder 54. Switch 42 is then rotated in a downward direction, e.g., 180 degrees (not shown), restoring the original position of distal implant holder 54, enabling subsequent passage thereof through sheath 24. Imaging device 70 is then straightened and extracted from bladder 80 via sheath 24.

Typically, as implant 120 is advanced through tissue of prostate 100, tissue of prostate 100 applies a frictional force to implant 120. In some embodiments, in order to reduce the effect of the frictional force applied to implant 120, implant 120 is coated with a low-friction coating, e.g., PTFE (Teflon), MoST, ADLC or the like. In some embodiments, the implant surface is polished, e.g., electro-polished, mechanically polished, or other, to reduce friction as implant 120 is advanced through the tissue of the patient. In some embodiments, implant 120 comprises a helical implant comprising a plurality of coils which are helically surrounded by a sheath coupled to a tube for passage therethrough of a lubricant into the sheath surrounding the implant (configuration shown hereinbelow with reference to Fig. 12). Typically, a lubricant is passed through the sheath surrounding implant 120. In such an embodiment, the sheath surrounding the implant is shaped to define holes (e.g., typically toward proximal end 122 of implant 120) for release of the lubricant externally to implant 120. The lubricant reduces a frictional force between the tissue of prostate 100 and implant 120. In some embodiments, implant 120 itself is a hollow, helical implant defining a helical lumen therein configured for passage of lubricant therethrough. The hollow, helical implant is shaped to define holes (e.g., typically toward proximal end 122 of implant 120) for release of the lubricant externally to implant 120. In such an embodiment, the implant is coupled to the tube for delivering the lubricant thereto, typically without the use of a sheath.

Reference is now made to Fig. 6, which is a schematic illustration of implant 120 implanted within prostate 100 of the patient, in accordance with an embodiment of the present invention. Once implant 120 is implanted within prostate 100, delivery tool shaft 25 and outer sheath 24 are extracted from within urethra 60. Following implantation of implant 120 within prostate 100, a post-operative diameter D2 of the portion of urethra 60 at prostate 100 is larger than diameter Dl of the portion of urethra 60 prior to implantation of implant 120. Implant 120 is generally rigid relative to the rigidity of the prostate. The implant thus supports the urethral tissue, minimizing restenosis of urethra 60 should prostate 100 continue to enlarge. Typically, implant 120 is selected to provide a length according to the needs of a given patient. A length of prostate 100 is measured prior to the implantation procedure such that an implant of a suitable length is selected. Typically, the end-to- end length of the coiled implant ranges from between 2.5 cm and 7 cm, to accommodate a prostate length of between 3 and 8.6 cm, respectively.

Typically, implant 120 supports prostatic tissue 100 surrounding urethra 60 without touching the urethral epithelium or other delicate tissue, and enlarges the lumen in urethra 60.

Figs. 7 and 8 show a system 400 comprising an extraction tool 300 configured to remove implant 120 from prostate 100, in accordance with an embodiment of the present invention. An outer sheath 230 is advanced distally through proximal end 62 of urethra 60 and toward bladder neck 64 of the patient.

Subsequently, a resection tool, e.g., a resectoscope (not shown), is advanced through sheath 230. The resection tool removes tissue surrounding distal end 126 of implant 120, thereby exposing a portion of implant 120 and enabling engaging thereof by extraction tool 300.

Typically, extraction tool 300 comprises a shaft 210 which is coupled at a distal end thereof to a mechanically adjustable clamp 224 via a hinge 240. Clamp 224 is advanced through sheath 230 into bladder 80 in an "extended" configuration with respect to hinge 240 (as shown in Fig. 7), and later assumes a "flexed" configuration with respect to the hinge, which enables clamp 224 to engage implant 120 (as shown in Fig. 8). An optical guide 250, e.g., a CCD, CIS, or CMOS sensor or an optical fiber- based system, guides the engaging and subsequent extraction of implant 120.

As shown in Fig. 8, a control element 320 is disposed along extraction tool 300 and enables a physician to control, from a location outside the body of the patient, various mechanical functions being performed at the distal end of tool 300. By proximal pulling of element 320, clamp 224 is flexed at hinge 240 with respect to shaft

210.

Additionally, extraction tool 300 comprises a proximal rotating element 360 and a distal rotating element 340. Proximal rotating element 360 regulates a distance between an upper jaw 222 and a lower jaw 220 of clamp 224. Upon an indication from imaging device 250 that clamp 224 surrounds a portion of implant 120, proximal rotating element 360 is rotated in a clockwise direction in order to reduce the distance between jaws 220 and 222 thus facilitating clamping of implant 120 by clamp 224.

The extraction process begins when clamp 224 engages a distal portion of implant 122. Distal rotating element 340 is rotated in a counterclockwise direction, i.e., in a direction opposite the direction used in the implantation procedure. Such rotation of element 340 moves implant 120 distally by rotating implant 120 about a longitudinal axis of extraction tool 300.

Once implant 120 is extracted fully from within prostate 100, jaws 220 and 222 are released from the distal portion of implant 120 by counterclockwise rotation of proximal rotating element 360. Element 320 is pushed distally, restoring clamp 224 to an extended configuration with respect to hinge 240. Clamp 224 is then pulled proximally, such that jaws 220 and 222 are aligned with a proximal portion of implant

120. Element 320 is again pulled proximally, and rotating element 360 is once again rotated in a clockwise direction such that jaws 220 and 220 are drawn together and engage the proximal end of implant 120 (configuration not shown).

Fig. 9 is a schematic illustration of extraction tool 300 extracting implant 120, in accordance with an embodiment of the present invention. The proximal end of the coiled implant is pulled in a proximal direction through a lumen of shaft 210. Due to the relative flexibility of implant 120 compared to extraction tool 300, pulling of implant 120 through sheath 230 enables implant 120 to assume an elongated, generally straightened configuration.

Reference is now made to Fig. 10, which is a schematic illustration of a system 200 comprising first and second transurethrally implantable prostatic implants 1000 and 1002, which surround the distal end of shaft 25 of delivery tool 22, in accordance with an embodiment of the present invention. Typically, implants 1000 and 1002 comprise helical, radially-expandable implants, e.g., coils, each having an inner diameter of at least 2.5 mm, e.g., between 2.5 mm and 15 mm. The respective diameters of the inner lumens of implants 1000 and 1002 enable implants 1000 and 1002 to be implanted in tissue surrounding urethra 60. Typically, the respective diameters of implants 1000 and 1002 are the same. Implants 1000 and 1002 typically comprise a flexible biocompatible material, e.g., nitinol or silicone.

First implant 1000 comprises a pointed proximal end 1010, and second implant 1002 comprises a pointed proximal end 1012. In some embodiments, proximal ends 1010 and 1012 are each coupled to, e.g., soldered to, a respective pointed tip, e.g., a needle. Typically, the needles coupled to each proximal end 1010 and 1012 comprise a generally rigid, biocompatible material, e.g., stainless steel, and are configured to provide strength to implants 1000 and 1002, respectively, to facilitate their puncture of and advancement through tissue of prostate 100. During transurethral advancement, implants 1000 and 1002 are disposed in a compressed state thereof. In some embodiments, implants 1000 and 1002 are compressed between respective proximal and distal implant holders 1020 and 1030. Typically, distal implant holders 1020 and 1030 function similarly to distal implant holder 54 as described hereinabove with reference to Figs. 2-5. Typically, the distal and proximal ends 1010 and 1012 of implants 1000 and 1002, respectively, are each shaped to define a slit. Each slit is configured for passage of respective fastening devices therethrough. The fastening devices maintain the compressed state of implants 1000 and 1002 during advancement thereof into bladder 80 of the patient. Once delivery tool 22 positions implants 1000 and 1002 in bladder 80, the fastening devices are released and implants 1000 and 1002 are allowed to expand to assume the configuration shown.

As shown, implants 1000 and 1002 are disposed in a relative spatial configuration in which implants 1000 and 1002 are coaxially disposed and rotationally offset 180 degrees with respect to each other, by way of illustration and not limitation. Additionally, a longitudinal position of implant 1000 overlaps at least in part (e.g., entirely, as shown) a longitudinal position of implant 1002. Implants 1000 and 1002 may be rotationally offset at any given angle with respect to each other. It is to be noted that although two implants are shown, any suitable number of implants may be corkscrewed into tissue of prostate 100. For example, three or four longitudinally- overlapping coiled implants may be coaxially disposed and rotationally offset 120 or 90 degrees with respect to each other. Typically, implants 1000 and 1002 are corkscrewed at the same time into tissue of prostate 100. During implantation: proximal end 1010 of the first implant 1000 punctures the tissue of prostate 100 at a first location thereof, and proximal end 1012 of second implant 1002 punctures the tissue of prostate 100, at a location 180 degrees from the first location.

The scope of the present invention includes sequentially implanting first and second implants 1000 and 1002. Delivery tool 22 is coupled to first implant 1000 and delivers implant 1000 to within bladder 80 and allows implant 1000 to expand, as described hereinabove in Figs. 1-4, with reference to the delivering and expanding of implant 120 within bladder 80. (As appropriate, delivery tool 22 may be sold already coupled to first implant 1000.) First implant 1000 punctures the tissue at a first location and is fully advanced into prostate 100 by delivery tool 22, as described hereinabove in Figs. 5-6, with reference to the implanting of implant 120 within prostate 100.

Once first implant 1000 is implanted, delivery tool 22 is removed from the patient, is coupled to second implant 1002, and is reintroduced within urethra 60 of the patient. (Alternatively, another delivery tool 22 coupled to implant 1002 is used in the following steps.) Second implant 1002 is advanced into bladder 80 of the patient, is allowed to expand within bladder 80, as described hereinabove in Figs. 1-4, with reference to the delivering and expanding of implant 120 within bladder 80. Second implant 1002 then punctures the tissue of prostate 100 at a second location which is rotationally offset 180 degrees from the first location. Second implant 1002 is corkscrewed into the tissue (as described hereinabove in Figs. 5-6, with reference to the implanting of implant 120 within prostate 100). Second implant 1002 is implanted coaxially with respect to a position of the implanted first implant 1000. Second implant 1002 is advanced fully through the tissue, until it is disposed coaxially and is rotationally offset by 180 degrees with respect to first implant 1000.

For either embodiment in which implants 1000 and 1002 are implanted simultaneously or sequentially, once implanted, implants 1000 and 1002 are configured to assume the relative spatial configuration, as shown and as described hereinabove. Typically, once implanted, implants 1000 and 1002 maintain substantially the same spatial relationship as shown in Fig. 10, i.e., coaxially disposed, longitudinally overlapping, and rotationally offset by 180 degrees with respect to each other.

In order to minimize the frictional force of prostate 100 on each implant 1000 and 1002 during implantation:

1) when implanted, the end-to-end respective lengths of each of the coiled implants range from between 2.5 cm and 7 cm, to accommodate a prostate length of between 3 cm and 9 cm, respectively, and

2) in accordance with the lengths of implants 1000 and 1002 in the abovementioned range, implants 1000 and 1002 are each shaped to define a pitch of between 8 mm and 23 mm, respectively.

For example, each of implants 1000 and 1002 may have an end-to-end length of about 4.5-5.5 cm and a pitch of about 14-16 mm.

The scope of the present invention includes the implantation of any suitable number of coiled implants around the urethra of the patient. For example, when one coiled implant is implanted in the tissue, the coiled implant may have a length of 4.5-5 cm and a pitch of approximately 8 mm. When first and second coiled implants (e.g., implants 1000 and 1002, as shown) are configured to be coaxially disposed and rotationally offset 180 degrees with respect to each other, each coiled implant 1000 and 1002 has a length of 4.5-5 cm and a pitch of approximately 16 mm (i.e., twice that indicated for an embodiment in which one coiled implant is implanted). In this manner, when the respective longitudinal positions of the implants are overlapped, and the implants are rotationally offset and coaxially disposed within tissue of prostate 100, the average effective pitch between adjacent coils of the coaxially disposed first and second coiled implants 1000 and 1002 is approximately 8 mm.

The total frictional force of the tissue of prostate 100 on any coiled implant during implantation is generally inversely related to the pitch and the length of the coil that is being implanted. That is, a small-pitch coiled implant has an along-the-coil length, i.e., the length of the wire when the coil is straightened, that is larger than an along-the-coil length of a high-pitch coiled implant. Thus, the overall frictional force applied to a small-pitch coiled implant is larger than the overall frictional force applied to a large-pitch coiled implant, because the frictional force applied to a small-pitch coiled implant is applied along a larger coil length, i.e., a larger cumulative surface area. Thus, as each of first and second coiled implants 1000 and 1002 is implanted within prostate 100, e.g., simultaneously or sequentially, the force needed in order to overcome the frictional force applied to each coiled implant 1000 and 1002 is smaller in comparison to the force applied to a coiled implant having a pitch similar to the average pitch of the combined first and second coiled implants 1000 and 1002. By reduction of the frictional force applied by the prostate to the implant during implantation, any undesired deformation of the portion of the implant that has not yet entered the prostate is reduced.

Fig. 1 1 shows a system 202 comprising a prostatic implant 1202, which surrounds the distal end of shaft 25 of delivery tool 22, in accordance with an embodiment of the present invention. Typically, implant 1202 is shaped to define a conical ly-shaped implant comprising a proximal coil 1220 having a larger diameter than a distal coil 1260. Typically, the respective diameters of adjacent coils decrease from proximal coil 1220 to distal coil 1260.

Prior to advancement of implant 1202 through urethra 60, delivery tool 22 is coupled to implant 1202 in a compressed state thereof. Delivery tool 22 maintains the compressed state of implant 1202 as it is advanced through urethra 60 and into bladder 80. Once within bladder 80, implant 1202 is allowed to expand, as described hereinabove in Figs. 1-4 with reference to the delivering and expanding of implant 120 within bladder 80. Pointed proximal end 122 of coil 1220 punctures the tissue of prostate 100 and is fully advanced into prostate 100 by delivery tool 22, as described hereinabove in Figs. 5-6 with reference to the implanting of implant 120 within prostate 100. Once first implant 1000 is implanted, delivery tool 22 is removed from the patient.

As proximal coil 1220 of implant 1202 is advanced through the tissue of prostate 100, the tissue applies a frictional force on the proximal coils of coiled implant 1202. In an attempt to continue corkscrewing into the tissue, the tissue exerts an increasingly larger cumulative frictional force on the increasing number of coils that are within the prostate. In response to the frictional force applied to the intra-prostate coils as they are corkscrewed into the tissue, the distal coils have a tendency to expand radially, such that the respective diameters of the distal coils are generally similar to the respective diameters of the proximal coils. In this manner, the overall outline of the entire implant when it has finished being inserted into the prostate tends to be generally rectangular (i.e., coils of same radius), rather than conical. Once implanted, the distal coils maintain their expanded diameters such that implanted implant 1202 resembles implanted implant 120 as shown in Fig. 5.

Fig. 12 shows an implant system 300 comprising a helical implant 302 helically surrounded by a sheath 304, in accordance with an embodiment of the present invention. Typically, implant system 300 is advanced toward the bladder and is implanted around the urethra, as described hereinabove in Figs. 1-6 with reference to the delivering and implantation of implant 120. Helical implant 302 is shaped to define a proximal end (not shown for clarity of illustration) comprising a pointed distal tip configured to puncture tissue of the prostate and facilitate ongoing penetration of implant system 300 within the tissue. Typically, the proximal end of helical implant 302 extends proximally from a proximal-most end of sheath 304 in order to facilitate unobstructed penetration of system 300 through tissue of the patient.

Typically, sheath 304 is shaped to define a plurality of holes 306 and is coupled at a distal end 308 thereof to a tube 310. Sheath 304 is fixedly attached to implant 302 at a site distal to the proximal end of implant 302 and is shaped to provide a helical lumen surrounding helical implant 302. Fluid is injected via tube 310 through the lumen of sheath 304. Holes 306 are configured for release of the fluid externally to implant system 300. In some embodiments, the fluid comprises a lubricant which passes externally to implant system 300 via holes 306 in order to reduce a frictional force between the tissue and implant system 300. In some embodiments, sheath 304 is shaped to define at least one hole at the proximal end thereof (configuration not shown for clarity of illustration). In such an embodiment, the fluid may comprise saline which is injected at high pressure through the lumen sheath 306 and externally to implant system 300 via the at least one hole in the proximal end of sheath 304 in order to cut tissue near the proximal tip of implant 302 as it advances through the tissue. It is to be noted that the scope of the present invention includes the use of the high-pressure fluid to cut tissue independently of or in combination with cutting tissue using helical implant 302.

In some embodiments, the hollow, helical lumen is configured for passage therethrough of a laser fiber to ablate tissue in the path of the implant as it is advanced therethrough. In some embodiments, an insulated RF transmitting wire having a non- insulated transmitting tip is advanced through the helical lumen of the hollow implant. It is to be noted that the scope of the present invention includes the use of the laser fiber and/or the RF wire independently of or in combination with helical implant 302.

In some embodiments, sheath 304 is shaped to define holes 304 only at the proximal end of the implant 300.

In some embodiments, helical implant 302 itself is a hollow, helical implant defining a helical lumen therein. Typically, the hollow, helical implant is functionally and structurally similar to and has the properties of sheath 304. In such an embodiment, the hollow, helical implant is typically implanted independently of sheath 304. In such an embodiment, the hollow, helical implant is coupled directly to tube 310.

Reference is now made to Figs. 7-12. It is to be noted that the scope of the present invention includes use of extraction tool 300 (Figs. 7-9) for extracting implants 1000 and 1002 (Fig. 10), 1202 (Fig. 1 1), and 300 (Fig. 12). Reference is still made to Figs. 7-12. In some embodiments of the present invention, a proximal clamp and a distal clamp are used in order to extract implants 120, 1000, 1002, 1202 and/or 300 from prostate 100 and bladder 80 of the subject. The distal clamp typically extracts the implant from the prostate (as described hereinabove with reference to clamp 224). Subsequent to the extraction, the proximal clamp is advanced into bladder 80 of the patient and engages the proximal end of the implant (in a manner as described hereinabove with respect to clamp 224). The proximal clamp is used to guide the implant through outer sheath 230 as the distal clamp remains within bladder 80 of the patient.

For some applications, techniques described herein are practiced in combination with techniques described in one or more of the references cited in the Background and Cross-References section of the present patent application, which are incorporated herein by reference.

The scope of the present invention includes application of the techniques described herein to body lumens other than the urethra, in order to treat a condition of patient. For example, implants 120, 1000, 1002, 1202, and 300 may be sized for implantation around another body lumen of the patient, such as the esophagus or a blood vessel which is connected to a body cavity.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

1. Apparatus, comprising: an implant; and a delivery tool, removably coupled to the implant, the tool configured to: advance the implant distally through a body lumen of a patient until the implant emerges at a distal end of the body lumen into a body cavity of the patient, and subsequently, implant the implant around the body lumen by retracting the implant.

2. The apparatus according to claim 1, wherein the implant comprises a low- friction coating.

3. The apparatus according to claim 1, wherein a surface of the implant comprises a polished surface configured to reduce friction of the implant during implantation.

4. The apparatus according to claim 1, wherein the implant is radially-expandable, and configured to expand upon emergence into the body cavity.

5. The apparatus according to claim 1, wherein the body lumen includes a urethra, and wherein the implant is configured to be implanted around the urethra.

6. The apparatus according to claim 1, wherein the implant comprises a transurethrally-implantable prostatic implant configured to be positionable in a prostate of the patient, and wherein the body lumen includes a urethra of the patient, the implant being shaped to define an implant lumen that surrounds an outer circumference of the urethra upon implantation.

7. The apparatus according to claim 1, wherein the implant is shaped to define an implant lumen that surrounds an outer circumference of the lumen upon implantation.

8. The apparatus according to claim 1, wherein the implant is shaped to define an inner diameter of at least 2.5 mm.

9. The apparatus according to claim 1, wherein the implant is shaped to define an inner diameter of between 2.5 mm and 15 mm.

10. The apparatus according to claim 1, wherein the implant is configured to prevent restenosis of the body lumen.

11. The apparatus according to claim 1, wherein the delivery tool is shaped to define a delivery tool lumen for passing an imaging device therethrough.

12. The apparatus according to claim 1, comprising an imaging device configured to guide the retraction of the implant.

13. The apparatus according to claim 1, wherein the delivery tool comprises a rotating element configured to corkscrew the implant into the tissue during the retracting of the implant.

14. The apparatus according to claim 1, wherein the delivery tool comprises a rotating element configured to corkscrew the implant into the tissue by rotation about a longitudinal axis of the delivery tool.

15. The apparatus according to any one of claims 1-14, wherein the implant comprises a flexible, biocompatible material selected from the group consisting of: nitinol and silicone.

16. The apparatus according to claim 15, further comprising a needle coupled to a proximal end of the implant.

17. The apparatus according to claim 16, wherein the needle comprises a rigid, biocompatible material configured to puncture tissue of the patient.

18. The apparatus according to claim 16, wherein the needle comprises stainless steel.

19. The apparatus according to any one of claims 1-14, wherein the implant comprises a coiled implant comprising at least one coil.

20. The apparatus according to claim 19, wherein the coiled implant is configured to corkscrew into a prostate of the patient.

21. The apparatus according to claim 19 wherein the coil comprises a conically- shaped coiled implant.

22. The apparatus according to claim 21, wherein a proximal coil of the conically- shaped coiled implant has a diameter that is larger than a diameter of a distal coil of the conically-shaped coiled implant.

23. The apparatus according to claim 19, wherein the coiled implant is configured to corkscrew into tissue of the patient.

24. The apparatus according to claim 23, wherein the coiled implant is shaped to define a proximal pointed end configured to puncture the tissue.

25. The apparatus according to claim 23, wherein the delivery tool is configured to implant the implant around the body lumen by corkscrewing the coiled implant into the tissue while retracting the implant.

26. The apparatus according to claim 25, wherein the tissue includes a prostate of the patient, and wherein the delivery tool is configured to corkscrew the coiled implant into the prostate.

27. The apparatus according to any one of claims 1-14, wherein the implant is shaped to define at least one slit configured for engaging of the delivery tool thereto.

28. The apparatus according to claim 27, wherein the implant comprises a coiled implant.

29. The apparatus according to claim 27, wherein the implant is shaped to provide a proximal slit and a distal slit.

30. The apparatus according to claim 29, wherein the delivery tool comprises a proximal locking mechanism and a distal locking mechanism, wherein the proximal locking mechanism is configured to engage the proximal slit of the implant, and wherein the distal locking mechanism is configured to engage the distal slit of the implant.

31. The apparatus according to claim 30, wherein the proximal and distal locking mechanisms are configured to maintain the implant in a compressed state thereof during the advancement of the implant into the body cavity of the patient.

32. The apparatus according to claim 31, wherein the implant is configured to expand radially following a disengagement of the proximal locking mechanism therefrom.

33. The apparatus according to any one of claim 1-14, wherein the implant is shaped to define a helical implant, and wherein the apparatus comprises a sheath shaped to define a hollow lumen helically surrounding the helical implant.

34. The apparatus according to claim 33, further comprising an ablation tool configured to be slidably advanced through the lumen of the sheath, and wherein the sheath is shaped to define at least one hole at a proximal end thereof configured for advancement therethrough of at least a portion of the ablation tool.

35. The apparatus according to claim 33, further comprising a flexible tube coupled to a portion of the sheath, the tube being configured to facilitate passage of a fluid through the lumen of the sheath, and wherein the sheath is shaped to define one or more holes configured for passage of the fluid externally to the implant.

36. The apparatus according to any one of claims 1-14, wherein the implant comprises a hollow, helical implant shaped to define a helical lumen thereof.

37. The apparatus according to claim 36, further comprising an ablation tool configured to be slidably advanced through the lumen of the implant, and wherein the implant is shaped to define at least one hole at a proximal end thereof configured for advancement therethrough of at least a portion of the ablation tool.

38. The apparatus according to claim 36, further comprising a flexible tube coupled to a portion of the helical implant, the tube being configured to facilitate passage of a fluid through the lumen of the implant, and wherein the implant is shaped to define one or more holes configured for passage of the fluid externally to the implant.

39. The apparatus according to any one of claims 1-14, wherein the implant comprises at least first and second implants.

40. The apparatus according to claim 39, wherein the implant comprises at least first and second helical implants.

41. The apparatus according to claim 39, wherein the at least first and second helical implants are configured to assume respective longitudinal positions and are configured to be disposed in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part.

42. The apparatus according to claim 41, wherein the first and second implants have the same diameter.

43. The apparatus according to claim 41, wherein the first and second helical implants each have a first pitch, and wherein, when disposed in the relative spatial configuration, the first and second implants define an effective second pitch which is less than half the first pitch.

44. The apparatus according to claim 41, wherein the delivery tool is configured to implant the first and second helical implants sequentially and position the first and second helical implants in the relative spatial configuration thereof.

45. The apparatus according to claim 41, wherein the first and second helical implants are configured to be coupled to the delivery tool in the relative spatial configuration.

46. The apparatus according to claim 45, wherein the first and second helical implants are configured to be simultaneously implanted around the body lumen of the patient.

47. The apparatus according to claim 46, wherein the at least first and second helical implants comprise respective transurethrally-implantable prostatic implants configured to be positionable in a prostate of the patient, and wherein the body lumen includes a urethra of the patient, the first and second implants being shaped to define respective implant lumens that surrounds an outer circumference of the urethra upon implantation.

48. The apparatus according to claim 46, wherein the first and second helical implants are shaped to define respective proximal pointed ends configured to puncture the tissue.

49. A method, comprising: distally advancing an implant through a body lumen of a patient until the implant emerges in a body cavity of the patient; and implanting the implant in tissue surrounding the body lumen by proximally retracting the implant.

50. The method according to claim 49, wherein the implant includes a radially- expandable implant, and wherein advancing the implant into the body cavity comprises facilitating the expansion of the implant within the body cavity of the patient.

51. The method according to claim 49, wherein the implant includes a conically- shaped coiled implant in which a diameter of a proximal coil thereof is larger than a diameter of a distal coil thereof, and wherein implanting the implant comprises implanting the conically-shaped coiled implant in the tissue of the patient.

52. The method according to any one of claims 49-51, wherein the body lumen includes a urethra and wherein implanting the implant comprises implanting the implant around the urethra.

53. The method according to claim 52, wherein implanting the implant comprises implanting the implant in a prostate of the patient.

54. The method according to any one of claims 49-51, comprising reversibly coupling the implant to a delivery tool, wherein advancing the implant comprises advancing the delivery tool, when it is reversibly coupled to the implant, through the body lumen of the patient.

55. The method according to claim 54, wherein implanting the implant comprises decoupling the implant from the delivery tool.

56. The method according to claim 54, wherein proximally retracting the implant comprises corkscrewing the implant into the tissue by rotating at least a portion of the delivery tool.

57. The method according to claim 54, wherein the tissue surrounding the body lumen includes a prostate of the patient, and wherein implanting the implant comprises corkscrewing the implant into the prostate by rotating at least a portion of the delivery tool.

58. The method according to claim 54, comprising imaging via an imaging device coupled to the delivery tool.

59. The method according to claim 58, wherein imaging comprises examining a bladder of the patient via the imaging device, prior to the advancing of the implant through the body lumen, by imaging a vicinity of a neck of the bladder of the patient.

60. The method according to claim 58, wherein imaging comprises imaging the implanting of the implant in the tissue surrounding the body lumen of the patient.

61. The method according to any one of claims 49-51, wherein distally advancing the implant comprises distally advancing at least first and second implants through the body lumen of the patient, and wherein implanting the implant comprises implanting the at least first and second implants in tissue surrounding the body lumen.

62. The method according to claim 61, wherein implanting the at least first and second implants in tissue surrounding the body lumen implant comprises corkscrewing the first and second implant into the prostate by rotating at least a portion of the delivery tool.

63. The method according to claim 62, wherein the tissue surrounding the body lumen includes a prostate of the patient, and wherein implanting the first and second implants comprises corkscrewing the first and second implants into the prostate by rotating at least a portion of the delivery tool.

64. The method according to claim 61 , further comprising: reversibly coupling the first implant to a delivery tool; and reversibly coupling the second implant to the delivery tool, and wherein advancing the first and second implants comprises advancing the first and second implants through the body lumen of the patient by the delivery tool.

65. The method according to claim 64, wherein implanting the first and second implants comprises decoupling the first and second implants from the delivery tool.

66. The method according to claim 64, wherein proximally retracting the implant comprises corkscrewing the first and second implants into the tissue by rotating at least a portion of the delivery tool.

67. The method according to claim 64, wherein implanting the first and second implants comprises implanting first and second implants in respective longitudinal positions thereof in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part.

68. The method according to claim 67, wherein reversibly coupling the first and second implants to the delivery tool comprises reversibly coupling to the delivery tool the first and second implants in the relative spatial configuration thereof, and wherein advancing the first and second implants comprises simultaneously advancing the first and second implants through the body lumen of the patient.

69. The method according to claim 67, wherein implanting the first and second implants in the relative spatial configuration thereof comprises: during a first period: reversibly coupling the first implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the first implant, through the body lumen of the patient, and implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant through a first opening created by the first implant, and during a second period subsequent to the first period: reversibly coupling the second implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the second implant, through the body lumen of the patient, and implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant through a second opening created by the second implant, wherein the second opening is rotationally offset from the first opening with respect to a longitudinal axis of the body lumen.

70. A method, comprising: at a first time, implanting an implant around a lumen of a patient by: advancing the implant distally through the lumen until the implant emerges at a distal end of the lumen into a cavity, and subsequently, implanting the implant around the lumen by proximally retracting the implant; and at a second time, extracting the implant from around the lumen by: moving the implant distally by rotating the implant, and subsequently, pulling the implant proximally through the lumen.

71. The method according to claim 70, wherein implanting the implant around the lumen comprises rotating the implant in a first direction thereof, and wherein extracting the implant comprises rotating the implant in a reverse direction to the first direction.

72. The method according to claim 70, wherein the implant includes a radially- expandable implant, and wherein advancing the implant comprises allowing the expansion of the implant within the cavity.

73. The method according to claim 70, wherein extracting the implant comprises: clamping a distal portion of the implant and moving the implant distally by rotating the implant; and clamping a proximal portion of the implant.

74. The method according to any one of claims 70-73, wherein the lumen includes a urethra of the patient and wherein pulling the implant comprises pulling the implant through the urethra.

75. The method according to claim 74, wherein rotating the implant comprises extracting the implant from a prostate of the patient.

76. Apparatus, comprising: at least first and second helical implants configured to assume respective longitudinal positions and to be disposed in a relative spatial configuration in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset, and the respective longitudinal positions of the first and second helical implants overlap at least in part; and a delivery tool, configured to be reversibly coupled to the at least first and second helical implants, the tool configured to: advance the at least first and second implants distally through a body lumen of a patient until the first and second implants emerge at a distal end of the body lumen into a body cavity of the patient, and implant the at least first and second implants in the relative spatial configuration thereof around the body lumen by retracting the first and second implants.

77. The apparatus according to claim 76, wherein the first and second implants have the same diameter.

78. The apparatus according to claim 76, wherein the first and second implants comprises low-friction coatings.

79. The apparatus according to claim 76, wherein the first and second implants are radially expandable, and configured to expand upon emergence into the body cavity.

80. The apparatus according to claim 76, wherein the body lumen includes a urethra, and wherein the first and second implants are configured to be implanted around the urethra.

81. The apparatus according to claim 76, wherein the first and second implants comprise respective transurethrally-implantable prostatic implants configured to be positionable in a prostate of the patient, and wherein the body lumen includes a urethra of the patient, the implants being shaped to define respective implant lumens that surround an outer circumference of the urethra upon implantation.

82. The apparatus according to claim 76, wherein the first and second implants are shaped to define respective implant lumens that surround an outer circumference of the lumen upon implantation.

83. The apparatus according to claim 76, wherein the first and second implants are shaped to define respective inner diameters of at least 2.5 mm.

84. The apparatus according to claim 76, wherein the first and second implants are shaped to define respective inner diameters of between 2.5 mm and 15 mm.

85. The apparatus according to claim 76, wherein the first and second helical implants each have a first pitch, and wherein, when disposed in the relative spatial configuration, the first and second implants define an effective second pitch which is less than half the first pitch.

86. The apparatus according to claim 76, wherein the delivery tool is configured to implant the first and second helical implants sequentially and position the first and second helical implants in the relative spatial configuration thereof.

87. The apparatus according to claim 76, wherein the first and second helical implants are shaped to define respective proximal pointed ends configured to puncture the tissue.

88. The apparatus according to any one of claims 76-87, wherein the first and second helical implants are configured to be coupled to the delivery tool in the relative spatial configuration.

89. The apparatus according to claim 88, wherein the first and second helical implants are configured to be simultaneously implanted around the body lumen of the patient.

90. A method, comprising: creating a first opening in tissue of a patient by puncturing the tissue; advancing through the first opening a first helical implant to a first longitudinal position; creating a second opening in tissue of the patient by puncturing the tissue, the second opening being rotationally offset from the first opening with respect to a longitudinal axis of the first helical implant when it has been advanced through the first opening; and advancing through the second opening a second helical implant to a second longitudinal position, in which: the first and second helical implants are disposed coaxially, the first and second helical implants are rotationally offset with respect to each other, and respective longitudinal positions of the first and second helical implants overlap at least in part.

91. The method according to claim 90, wherein advancing through the first opening the first helical implant to the first longitudinal position comprises corkscrewing the first helical implant into the tissue, and wherein advancing through the second opening the second helical implant to the second longitudinal position comprises corkscrewing the second helical implant into the tissue.

92. The method according to claim 91, wherein the tissue includes a prostate of the patient, and wherein advancing the first and second helical implants comprises corkscrewing the first and second helical implants into the prostate.

93. The method according to claim 90, further comprising: distally advancing the first and second helical implants through a body lumen of a patient until the first and second implants emerge in a body cavity of the patient, and wherein: advancing through the first opening the first helical implant to the first longitudinal position comprises implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant, and advancing through the second opening the second helical implant to the second longitudinal position comprises implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant.

94. The method according to claim 93, further comprising: reversibly coupling the first implant to a delivery tool; and reversibly coupling the second implant to the delivery tool, and wherein distally advancing the first and second implants comprises distally advancing the first and second implants through the body lumen of the patient by the delivery tool.

95. The method according to claim 94, wherein implanting the first and second implants comprises decoupling the first and second implants from the delivery tool.

96. The method according to claim 94, wherein proximally retracting the implants comprises corkscrewing the first and second implants into the tissue by rotating at least a portion of the delivery tool.

97. The method according to claim 94, wherein reversibly coupling the first and second implants to the delivery tool comprises reversibly coupling to the delivery tool the first and second implants in the relative spatial configuration thereof, and wherein advancing the first and second implants comprises simultaneously advancing the first and second implants through the body lumen of the patient.

98. The method according to claim 94, wherein implanting the first and second implants in the relative spatial configuration thereof comprises: during a first period: reversibly coupling the first implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the first implant, through the body lumen of the patient, and implanting the first implant in tissue surrounding the body lumen by proximally retracting the first implant through a first opening created by the first implant, and during a second period subsequent to the first period: reversibly coupling the second implant to the delivery tool, advancing the delivery tool, when it is reversibly coupled to the second implant, through the body lumen of the patient, and implanting the second implant in tissue surrounding the body lumen by proximally retracting the second implant through a second opening created by the second implant, wherein the second opening is rotationally offset from the first opening with respect to a longitudinal axis of the body lumen.

99. Apparatus, comprising: a helical implant; and a sheath, helically surrounding the implant, the sheath shaped to define one or more holes.

100. The apparatus according to claim 99, wherein the sheath is shaped to define three or more holes.

101. The apparatus according to claim 99, wherein the helical implant is shaped to define an inner diameter thereof that is between 2.5 mm and 15 mm.

102. The apparatus according to claim 99, wherein the sheath tightly surrounds the helical implant.

103. The apparatus according to any one of claims 99-102, further comprising: a lubricant; and a pressure source configured to push the lubricant (a) from within a space between the helical implant and the sheath, (b) through the one or more holes, (c) to outside of the sheath.

104. Apparatus, comprising: a helical implant having a wall shaped to define a plurality of holes, the helical implant shaped to define a helical lumen thereof; a lubricant, disposed within the lumen; and a pressure source, configured to push the lubricant through the plurality of holes.

105. The apparatus according to claim 104, wherein the pressure source comprises a syringe.

106. The apparatus according to claims 104 or 105, wherein the helical implant is shaped to define an inner diameter thereof that is between 2.5 mm and 15 mm.