PATENT DOCUMENT

Abstract:
Apparatus for advancing a vascular implant into a blood vessel. The apparatus comprises a first elongate member, the first elongate member having sufficient column strength to function as a pusher member; and a second elongate member, the second elongate member being thinner than the first elongate member and extending to a distal end located at a first point which is at or near a distal end of the first elongate member. The elongate members form an implant retaining portion while the distal end of the second elongate member is located at the first point. The implant retaining portion is located proximal of the first point. The implant retaining portion comprises a space located between the elongate members and configured for receiving an implant portion, with the first elongate member on one side of the space and the second elongate member on another side. The implant retaining portion further comprises a proximal side and a distal side which further circumscribe the space. The proximal and distal sides are effective to prevent an implant received in the retaining portion from moving out of engagement with the retaining portion as the first elongate member is moved distally and proximally. The implant retaining portion is removable by withdrawing the second elongate member in a proximal direction with respect to the first elongate member, thereby moving the distal end of the elongate member proximally beyond the former location of the implant retaining portion. Associated methods, and other apparatus and methods, are also disclosed.

Full Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) to the following U.S. provisional patent application Ser. No. 61/139,509, filed Dec. 19, 2008, titled METHOD AND APPARATUS FOR STORAGE AND/OR INTRODUCTION OF OCCLUDING IMPLANT FOR HOLLOW ANATOMICAL STRUCTURE; Ser. No. 61/230,252, filed Jul. 31, 2009, titled METHOD AND APPARATUS FOR STORAGE AND/OR INTRODUCTION OF OCCLUDING IMPLANT FOR HOLLOW ANATOMICAL STRUCTURE; and Ser. No. 61/249,515, filed Oct. 7, 2009, titled METHOD AND APPARATUS FOR STORAGE AND/OR INTRODUCTION OF OCCLUDING IMPLANT FOR HOLLOW ANATOMICAL STRUCTURE. The entire disclosure of each of the above-mentioned provisional applications (less any material incorporated by reference therein, and less their Appendices) is incorporated by reference herein. 
    
    
     BACKGROUND 
     Field 
     Treatment of hollow anatomical structures such as blood vessels, hollow organs, fallopian tubes, gastric structures, etc. 
     Related Art 
     Referring to  FIG. 1 , the human venous system of the leg A comprises the superficial venous system, shown in white, and the deep venous system, shown in black, with perforating veins connecting the two systems. The superficial system includes the long or great saphenous vein B and the small saphenous vein C. The deep venous system includes the anterior and posterior tibial veins D, E, which unite to form the popliteal vein F, which in turn becomes the femoral vein G when joined by the short saphenous vein C. The femoral vein G and the great saphenous vein B join at the sapheno-femoral junction H. 
     The venous system contains numerous one-way valves for directing antegrade blood flow back to the heart. When an incompetent valve is in the flow path, the valve is unable to close, and retrograde flow of the blood away from the heart cannot be stopped. When a venous valve fails, increased strain and pressure occur within the lower venous sections and overlying tissues, sometimes leading to additional, distal valvular failure. Two venous conditions or symptoms that often result from valve failure are varicose veins and more symptomatic chronic venous insufficiency. Current treatments of venous insufficiency include surgical procedures such as vein stripping, vein-segment transplant, and ligation by ablation. 
     Vein stripping typically consists of tying off, or ligating, and removing the saphenous vein. Vein segment transplant has been employed in certain organ transplant procedures; however, it is not generally employed in the superficial venous system in humans. Ligation by ablation involves the cauterization or coagulation of vascular lumina using thermal energy applied through a delivery device. Energy introduced into the vein lumen causes the vein wall to shrink in cross-sectional diameter or completely collapse, thereby reducing or completely blocking blood flow through the vein. 
     An alternative treatment involves placement of an occluding implant in the hollow anatomical structure, such as the great saphenous vein. As an example, the implant can be a fibrous body, optionally textured to impart bulk. The implant causes a partial occlusion of the hollow anatomical structure, followed by a complete or substantially complete occlusion, such as by formation of an organic fibrotic occlusion resulting from the body&#39;s natural foreign body healing response. 
     SUMMARY 
     A non-exhaustive summary of embodiments disclosed herein follows. 
     The present disclosure includes, in a first embodiment, a system for introducing an occluding implant into a hollow anatomical structure, such as a vein, comprising an introducer sheath and an apparatus proximally coupled to the introducer sheath. The introducer sheath comprises a shaft sized for insertion into the hollow anatomical structure and forming a lumen. A proximal opening of the introducer sheath provides access to the shaft lumen. The apparatus comprises an occluding implant, an implant storage unit forming a chamber (e.g. an elongate chamber) that houses the implant, and an introducer coupled to the implant. An exit opening of the apparatus is in communication with the implant storage unit chamber. The introducer is movable relative to the implant storage unit and the introducer sheath and has a travel direction through the implant storage unit exit opening and the introducer sheath proximal opening to thereby move the implant from the implant storage unit chamber to the introducer sheath shaft lumen. 
     Further optional features and variations of this first embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the first embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The introducer can comprise a pushrod stored generally in a loop configuration, and the implant can be stored (and/or the implant storage unit chamber can be located) alongside the pushrod so that it extends and curves along and next to the loop formed by the pushrod (or the pushrod housing). The implant (and/or the implant storage unit chamber) can generally conform to the shape of the loop as it extends and curves along the loop. The pushrod and the implant can be contained (and/or the implant storage unit chamber can be formed) in a common casing generally shaped like a ring. The ring can generally conform to the pushrod loop and form a radially inward deflection from the ring configuration to expose a portion of the pushrod for manual gripping. The pushrod and the implant can diverge at distal portions thereof so that the pushrod exits the implant storage unit to expose a length of the pushrod for manual gripping. The pushrod and implant can be connected to each other near the distal tip of the pushrod. 
     The exit opening and the proximal opening can be aligned with each other. For example, the exit opening and the proximal opening can be axially aligned. The exit opening and the proximal opening can be directly adjacent each other when the apparatus is coupled to the introducer sheath. 
     The apparatus can further comprise a coupler coupling the apparatus to the introducer sheath. The coupler can include a proximal coupler disposed on the apparatus, such as on the implant storage unit, and a distal coupler disposed on the introducer sheath, whereby coupling of the proximal and distal couplers effects the coupling of the apparatus to the introducer sheath. The introducer sheath can further comprise a hub located at a proximal end of the sheath and forming the proximal opening, and the distal coupler can be disposed on the hub. The apparatus exit opening can be formed by the coupler, such as by the proximal coupler. The coupler can be configured to automatically align the exit opening and the proximal opening upon coupling the apparatus to the introducer sheath. 
     The implant storage unit can define a storage axis, and the introducer and the implant can have a common travel direction through the exit opening and into the introducer sheath, wherein the storage axis is offset relative to the common travel direction. For example, the storage axis can be angularly offset relative to the common travel direction. The storage axis can be offset at an obtuse angle relative to the common travel direction. 
     The implant can comprise a fibrous body. The fibrous body can be made of a bioresorbable material. In one example, the fibrous body can have a natural expanded condition and can be compressed upon application of a compressive force. For example, when the implant is in the chamber of the implant storage unit, the implant body can assume a storage condition in which the implant body is in the naturally expanded condition, and when the implant is in the lumen of the introducer sheath shaft, the shaft can compress the implant body to an introduction condition. Further, when the implant is implanted in the hollow anatomical structure upon removal of the introducer sheath from the hollow anatomical structure, the implant body can expand from the introduction condition to an implantation condition, wherein the thickness of the implant body is greater than when in the introduction condition and less than when in the storage condition. To accommodate the implant body in the storage condition, the implant storage unit can have a gauge (or cross-sectional size, or lumen inside diameter) greater than or equal to the size or thickness of the implant body when in the naturally expanded condition. Further, the gauge (or cross-sectional size, or lumen inside diameter) of the implant storage unit can be greater than a gauge (or lumen inside diameter) of the introducer sheath shaft. The apparatus can include a guide to facilitate compression of the implant body during movement of the introducer and, thereby, the implant from the implant storage unit to the introducer sheath. The guide can be, for example, a distally tapering frustoconical wall, and the frustoconical wall can terminate at the exit opening. The guide can be formed in a coupler coupling the apparatus to the introducer sheath. 
     The implant can include a tether. In one example, the implant comprises an elastic fibrous body, and the tether can be inelastic. The fibrous body can comprise multiple bulked fibers, and the tether can comprise an inelastic yarn. Further, the tether can be made of a bioresorbable material, such as the same bioresorbable material as the implant body. The tether can be coupled to the fibrous body at a distal end of the fibrous body. As an example, when the implant is fully inserted into the hollow anatomical structure, a distal end of the tether is located at the distal end of the fibrous body in the hollow anatomical structure, and a proximal end of the tether is attached externally of the hollow anatomical structure to prevent distal migration of the fibrous body in the hollow anatomical structure. The proximal end of the tether can be secured to an external surface of the body, such as by adhesive tape. The proximal end of the tether can be incorporated into sutures that close an access site for the hollow anatomical structure. 
     The implant storage unit can further comprise an end cap closing an open proximal end of the implant storage unit. The end cap can be removable. In one example, the implant can be anchored to the proximal end of the implant storage unit by the end cap, such as by the implant body and/or the tether being disposed between the end cap and the implant storage unit. 
     The introducer can comprise a pushrod. The pushrod can be coupled to a distal end of the implant; for example, a distal end of the pushrod can be coupled to a distal end of the implant. The pushrod can form a lumen that houses a wire. The distal end of the pushrod can be closed, such as by a plug, and a distal end of the wire can be attached to the closed distal end. The pushrod can further include first and second openings through which the wire passes to form an implant retaining portion externally of the pushrod lumen and between the openings. The implant can be held between the implant retaining portion and the pushrod. The first opening can be located proximally of the second opening. For example, the first and second openings can be linearly arranged along the pushrod. A proximal end of the wire can project from the pushrod to enable application of a proximal force to the wire. As an example, the proximal end of the wire can extend out of an open proximal end of the pushrod. Application of the proximal force to the wire can effect detachment of the distal end of the wire from the pushrod. Continued application of the proximal force effects liberation of the implant from the introducer as the implant retaining portion of the wire retracts into the pushrod lumen via the first, proximal opening. 
     The pushrod can be stored externally of the implant storage unit and enter the implant storage unit near a distal end of the implant storage unit. For example, the pushrod can extend through an aperture formed near the distal end of the implant storage unit. The aperture can be aligned with the apparatus exit opening such that the distal end of the pushrod is aligned with the exit opening for movement of the pushrod in the travel direction through the exit opening. The aperture and the exit opening can be axially aligned. The apparatus can further include a container that houses the pushrod externally of the implant storage unit. For example, the container can comprise a reel, or a coiled tube mounted to the implant storage unit. An exposed portion of the pushrod between the container/tube/reel and the aperture through the pushrod can extend into the implant storage unit provides a gripping area for a user to grasp and move the pushrod. 
     The apparatus comprising the implant, the implant storage unit, the coupler, and the introducer can be provided as an assembled kit wherein the implant is assembled in the implant storage unit and coupled to the introducer. When the coupler comprises the proximal and distal couplers, the proximal and distal couplers can be provided in a decoupled condition or a coupled condition. When the proximal and distal couplers are provided in the coupled condition, the user decouples the distal coupler from the proximal coupler prior to use of the apparatus. As one alternative, the kit can further include the introducer sheath. When the kit includes the introducer sheath, the introducer sheath and the apparatus can be provided as coupled or decoupled. 
     In a second embodiment, an apparatus for introducing an occluding implant into a hollow anatomical structure, such as a vein, comprises an occluding implant, an implant storage unit forming a chamber (e.g. an elongate chamber) that houses the implant, and an introducer coupled to the implant. An exit opening of the apparatus is in communication with the implant storage unit chamber. The introducer is movable relative to the implant storage unit and has a travel direction through the implant storage unit exit opening to thereby move the implant from the implant storage unit chamber to externally of the apparatus. 
     The present disclosure contemplates and includes optionally employing in the second embodiment, the optional features and variations of the first embodiment identified above, either alone or in any feasible combination of two or more such optional features and variations. 
     The introducer can comprise a pushrod stored generally in a loop configuration, and the implant can be stored (and/or the implant storage unit chamber can be located) alongside the pushrod so that it extends and curves along and next to the loop formed by the pushrod (or the pushrod housing). The implant (and/or the implant storage unit chamber) can generally conform to the shape of the loop as it extends and curves along the loop. The pushrod and the implant can be contained (and/or the implant storage unit chamber can be formed) in a common casing generally shaped like a ring. The ring can generally conform to the pushrod loop and form a radially inward deflection from the ring configuration to expose a portion of the pushrod for manual gripping. The pushrod and the implant can diverge at distal portions thereof so that the pushrod exits the implant storage unit to expose a length of the pushrod for manual gripping. The pushrod and implant can be connected to each other near the distal tip of the pushrod. 
     The present disclosure also includes methods of storing and/or introducing an occluding implant into a hollow anatomical structure, such as a vein. In a third embodiment, a method employs a system comprising an introducer sheath and an apparatus. The introducer sheath comprises a shaft sized for insertion into the hollow anatomical structure and forming a lumen. A proximal opening of the introducer sheath provides access to the shaft lumen. The apparatus comprises an occluding implant, an implant storage unit forming an elongate chamber that houses the implant, and an introducer coupled to the implant. An exit opening of the apparatus is in communication with the implant storage unit chamber. The method can optionally comprise inserting the introducer sheath shaft into the hollow anatomical structure. The method can further comprise coupling the apparatus to a proximal end of the introducer sheath, thereby arranging the implant storage unit exit opening and the introducer sheath proximal opening to establish a travel direction of the introducer therethrough, and distally advancing the introducer along the travel direction to move the implant from the implant storage unit, through the implant storage unit exit opening, through the introducer sheath proximal opening, and into the introducer sheath shaft lumen. 
     Further optional features and variations of this third embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the third embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The method can further include continuing the distal advancement of the introducer and the implant into the introducer sheath shaft lumen. For example, the advancement of the introducer and the implant can continue until the introducer reaches a distal end of the introducer sheath shaft. In the case where the hollow anatomical structure is the greater saphenous vein, the advancement of the introducer and the implant continues until a distal end of the implant is located below the sapheno-femoral junction. As an example, the distal end of the implant can be located just below, for example about 2.5 cm below, the sapheno-femoral junction. 
     The method can further include compressing the implant during the distal advancement of the introducer along the travel direction. For example, the implant can be compressed in the apparatus while moving the implant through the exit opening. The apparatus can include a guide in the form of a distally tapering frustoconical wall that terminates at the exit opening, and the compression of the implant further includes moving the implant through the guide to gradually compress the implant from a storage condition when in the implant storage unit to an introduction condition when the implant moves through the exit opening. When the implant is in the storage condition, the implant can assume a naturally expanded condition. 
     The method can further include removing the introducer sheath from the hollow anatomical structure. Further, the method can continue with removing the introducer from the hollow anatomical structure. Prior to removing the introducer, the method can include decoupling the implant from the introducer, thereby leaving the implant in the hollow anatomical structure following removal of the introducer sheath. The introducer can comprise a pushrod having an implant retaining wire attached to the pushrod, wherein the wire facilitates coupling the implant to the pushrod, and the decoupling of the implant from the introducer comprises detaching the wire from the pushrod. For example, the detaching of the wire from the pushrod can comprise applying a proximal force to the wire. 
     The method can include expanding the implant during the removing of the introducer sheath from the hollow anatomical structure. For example, the expanding of the implant can comprise expanding the implant from an introducing condition when the implant is in the introducer sheath shaft to an implantation condition when the implant is in the hollow anatomical structure. Thus, following the example provided above, the method can comprise compressing the implant from a storage condition when in the implant storage unit to the introduction condition when the implant moves through the exit opening and into the introducer sheath shaft, and the compression can be followed by the expanding of the implant from the introduction condition to the implantation condition. The thickness of the implant in the implantation condition can be smaller than in the storage condition. 
     The method can further comprise decoupling the apparatus from the introducer sheath prior to the removing of the introducer sheath from the hollow anatomical structure. The decoupling of the apparatus from the introducer sheath can comprise trimming the implant proximally of the introducer sheath. 
     The implant can comprise a fibrous body and a tether coupled to the body, and the method can comprise attaching the tether externally of the hollow anatomical structure to prevent distal migration of the body in the hollow anatomical structure. The attaching of the tether can occur after the removing of the introducer sheath and the introducer from the hollow anatomical structure. The attaching of the tether can comprise securing a proximal end of the tether to an external surface of the body, such as by adhesive tape. The attaching of the tether can comprise incorporating the proximal end of the tether into sutures that close an access site for the hollow anatomical structure. 
     A fourth embodiment comprises an apparatus for delivering an implant. The apparatus comprises a pushrod, a distal exit opening, and a pushrod passage receiving the pushrod and located proximal of the distal exit opening. The pushrod passage and the distal exit opening are located on a delivery path. The apparatus further comprises an elongate vascular implant stored in the apparatus. A portion of the implant is positioned at a first location on the delivery path, and the implant extends from the first location in a direction divergent from the delivery path. 
     Further optional features and variations of this fourth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the fourth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The pushrod can be stored in the apparatus generally in a loop configuration, and the implant can be stored (and/or an implant chamber can be located) in the apparatus alongside the pushrod so that the implant/chamber extends and curves along and next to the loop formed by the pushrod (or the pushrod housing). The implant (and/or the implant chamber) can generally conform to the shape of the loop as it extends and curves along the loop. The apparatus can include a casing generally shaped like a ring which contains the stored pushrod and the implant/chamber. The ring can generally conform to the pushrod loop and implant/chamber, and form a radially inward deflection from the ring configuration to expose a portion of the pushrod for manual gripping. The pushrod and the implant can diverge at distal portions thereof so that the pushrod exits the casing to expose a length of the pushrod for manual gripping. The pushrod and implant can be connected to each other near the distal tip of the pushrod. 
     The implant can comprise a bioabsorbable fibrous implant. The apparatus can further comprise an implant storage unit, and the implant can be stored in the unit in an expanded condition. At least a proximal portion of the implant can be stored in the unit with substantially no longitudinal bunching or folding. 
     The implant can be coupled to the pushrod at the first location. 
     A system can comprise the apparatus, and an introducer sheath coupled to the apparatus, wherein a proximal opening of the introducer sheath is aligned with the distal exit opening and located on the delivery path. The introducer sheath can be removably coupled to the apparatus. 
     The apparatus can further comprise an implant storage chamber which extends in a direction divergent from the delivery path, wherein the implant is stored in the storage chamber. The implant storage chamber can have a generally straight configuration. The implant storage chamber can have a curved configuration. 
     The pushrod can extend proximally from the pushrod passage to an exterior of the apparatus to facilitate gripping the pushrod at a location proximal of the passage. The apparatus can further comprise a pushrod container, wherein the pushrod extends further proximally from the pushrod passage into the pushrod container. The apparatus can further comprise an implant storage unit containing the implant, wherein the pushrod container is connected to the implant storage unit. 
     The apparatus can further comprise an implant chamber in which the implant is located. The implant chamber can have a proximal end and a distal end, wherein a portion of the pushrod is exposed to permit manual gripping at a grip location distal of the proximal end of the implant chamber. The grip location can be closer to the distal end of the implant chamber than to the proximal end thereof. 
     A fifth embodiment comprises a method of facilitating delivery of a vascular implant. The method can comprise the following acts, in any feasible order: (a) providing a delivery device comprising an implant chamber and a pushrod, the delivery device defining a delivery path passing through an exit opening of the delivery device; (b) holding the implant in the implant chamber; (c) connecting a distal end of the implant to a distal tip region of the pushrod; (d) positioning the distal tip region of the pushrod and the distal end of the implant on the delivery path, aligned with the exit opening, so that a distal movement of the pushrod causes the pushrod and the implant to advance through the exit opening; and (e) facilitating rapid connection of an introducer sheath to the delivery device and alignment of a proximal opening of the introducer sheath with the exit opening via a coupler, separate from the introducer sheath, configured to receive a proximal portion of the introducer sheath and connect to the delivery device distal of the exit opening. 
     Further optional features and variations of this fifth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the fifth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The method can further comprise sterilizing the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     The method can further comprise packaging the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     The method can further comprise providing to a medical practitioner the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     Holding the implant in the implant chamber can comprise holding the implant in an expanded state. The implant can tend toward the expanded state in the absence of external forces. 
     Holding the implant in the implant chamber can comprise holding at least a proximal portion of the implant with substantially no longitudinal bunching or folding. 
     The implant can comprise a bioabsorbable fibrous implant. 
     The delivery device can comprise a pushrod container and the method can further comprise storing a proximal portion of the pushrod in the pushrod container. 
     The method can further comprise arranging the implant chamber along a direction that diverges from the delivery path, and still further comprise locating the distal tip region of the pushrod on the delivery path. 
     The method can further comprise exposing a portion of the pushrod to permit manual gripping at a grip location distal of a proximal end of the implant chamber. The grip location can be closer to a distal end of the implant chamber than to the proximal end thereof. 
     The coupler can comprise a longitudinal opening formed therethrough, that aligns with the exit opening upon connection of the coupler to the delivery device. The coupler can further comprise a slot formed along a side of the coupler and communicating with the longitudinal opening to allow sideways entry of the introducer sheath into the coupler. 
     A sixth embodiment comprises method of facilitating delivery of an elongate, expandable, bioabsorbable vascular implant. The method can comprise the following acts, in any feasible order: (a) providing a delivery device comprising an implant chamber and a pushrod, the delivery device defining a delivery path passing through an exit opening of the delivery device; (b) holding the elongate, expandable, bioabsorbable vascular implant in the implant chamber in an expanded state; (c) connecting a distal end of the implant to a distal tip region of the pushrod; (d) positioning the distal tip region of the pushrod and the distal end of the implant on the delivery path, aligned with the exit opening, so that a distal movement of the pushrod causes the pushrod and the implant to advance through the exit opening; and (e) exposing a portion of the pushrod to permit manual gripping at a grip location proximal of a distal end of the implant chamber. 
     Further optional features and variations of this sixth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the sixth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The grip location can be closer to a proximal end of the implant chamber than to a distal end thereof. Exposing the portion of the pushrod can comprise arranging the implant chamber along a direction that diverges from the delivery path. 
     The method can further comprise sterilizing the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     The method can further comprise packaging the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     The method can further comprise providing to a medical practitioner the delivery device including the pushrod and the implant chamber as an assembled unit, with the implant in the implant chamber. 
     The implant can tend toward the expanded state in the absence of external forces. 
     Holding the implant in the implant chamber can comprise holding at least a proximal portion of the implant with substantially no longitudinal bunching or folding. 
     The delivery device can comprise a pushrod container, and the method can further comprise storing a proximal portion of the pushrod in the pushrod container. 
     The method can further comprise locating the distal tip region of the pushrod on the delivery path. 
     A seventh embodiment comprises an apparatus for introducing an implant into a hollow anatomical structure. The apparatus comprises a storage unit, an elongate vascular implant stored inside the storage unit and having a distal end, and a pushrod at least partially stored inside the storage unit and having a distal end coupled to the distal end of the implant. The implant diverges from adjacency with the pushrod as the implant extends away from the distal end of the pushrod, such that the pushrod forms a force application region near the distal end of the pushrod, the force application region being accessible for force application but separated from the implant. 
     Further optional features and variations of this seventh embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the seventh embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The storage unit can comprise a wall separating the force application region from the implant. The pushrod can be partially located exteriorly of the storage unit to expose a length of the pushrod, which forms the force application region, for gripping and can pass through the wall near a distal end of the storage unit. 
     The storage unit can comprise an exit opening, and the implant can diverge from adjacency with the pushrod in a proximal direction from the exit opening and can converge with the pushrod proximally of the exit opening as the pushrod is advanced toward and through the exit opening. The implant can be drawn toward and through the exit opening by the pushrod as the pushrod is so advanced. The storage unit can define a storage axis, the pushrod and the implant can have a common travel direction through the exit opening, and the storage axis can be offset relative to the common travel direction. The storage axis can be non-linear. 
     The storage unit is generally shaped like a ring. 
     The implant can comprise an occluding implant. 
     The implant can comprise a bioresorbable implant. 
     An eighth embodiment comprises an apparatus for introducing an implant into a hollow anatomical structure. The apparatus comprises a storage unit comprising an exit opening, an implant storage portion, and a pushrod storage portion spaced from the implant storage portion and converging with the implant storage portion at the exit opening, an elongate vascular implant stored inside the implant storage portion and having a distal end, and a pushrod at least partially stored inside the pushrod storage portion and having a distal end coupled to the distal end of the implant. The pushrod forms a force application region near the distal end of the pushrod. The implant and the pushrod continually converge proximally of the exit opening as the pushrod is advanced toward and through the exit opening. 
     Further optional features and variations of this eighth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the eighth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant can be drawn toward and through the exit opening by the pushrod as the pushrod is so advanced. 
     The implant storage portion and the pushrod storage portion can be physically separated from each other. 
     The storage unit can comprise a common casing defining the implant storage portion and the pushrod storage portion. The common casing can be generally shaped like a ring. 
     The pushrod can be partially located exteriorly of the pushrod storage portion to expose a length of the pushrod for gripping and can enter the storage unit near a distal end of the storage unit. 
     The implant can comprise an occluding implant. 
     The implant can comprise a bioresorbable implant. 
     A ninth embodiment comprises a method for introducing an implant into a hollow anatomical structure. The method can comprise the following acts, in any feasible order: (a) inserting an introducer sheath into the hollow anatomical structure; (b) coupling a delivery apparatus to a proximal end of the introducer sheath, the delivery apparatus storing a pushrod and an implant along divergent directions; (c) converging the pushrod and the implant along a common axis defining a travel direction within the delivery apparatus; and (d) distally advancing the converged pushrod and implant along the travel direction through an exit opening of the delivery apparatus and into the introducer sheath. 
     Further optional features and variations of this ninth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the ninth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant can comprise an occluding implant. 
     Converging the pushrod and the implant can comprise distally advancing the pushrod to draw the implant toward the common axis. 
     Distally advancing the converged pushrod and implant can comprise compressing the implant from an expanded condition to a compressed condition. The method can further comprise distally advancing the converged pushrod and implant through the introducer sheath and into the hollow anatomical structure and expanding the implant in the hollow anatomical structure from the compressed condition to the expanded condition. 
     Distally advancing the converged pushrod and implant can comprise gripping an exposed portion of the pushrod proximal of the converged pushrod and implant. 
     The hollow anatomical structure can comprise a blood vessel. The method can further comprise occluding a lumen of the blood vessel with the implant. The implant can be bioresorbable. 
     The hollow anatomical structure can comprise a vein in a leg. 
     A tenth embodiment comprises an apparatus for introducing an implant into a hollow anatomical structure. The apparatus comprises a storage unit having an exit opening and defining a chamber in communication with the exit opening, an elongate, self-expanding vascular implant having an expanded condition and stored within the chamber in the expanded condition, proximal of the exit opening, and a pushrod having a distal end aligned with and proximal of the exit opening. The pushrod is pre-assembled to a distal end of the implant. 
     Further optional features and variations of this tenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the tenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The pushrod and the implant can have a common travel direction through the exit opening such that the implant is drawn toward and through the exit opening by the pushrod as the pushrod is advanced toward and through the exit opening. 
     The apparatus can further comprise a guide proximal of the exit opening for facilitating compression of the implant from the expanded condition to a compressed condition as the pushrod is advanced toward and through the exit opening. 
     The pushrod can be stored within the chamber. 
     The chamber can be generally shaped like a ring. 
     The pushrod can be partially located exteriorly of the storage unit to expose a length of the pushrod for gripping and can enter the storage unit near a distal end of the storage unit. 
     The implant can comprise an occluding implant. 
     The implant can comprise a bioresorbable implant. 
     An eleventh embodiment comprises an apparatus for introducing an implant into a hollow anatomical structure. The apparatus comprises a storage unit having an exit opening and defining a chamber in communication with the exit opening, an elongate vascular implant having a first configuration in which the implant is larger than the exit opening and a second configuration in which the implant is smaller than the exit opening, and a pushrod having a distal end aligned with and proximal of the exit opening. The pushrod is pre-assembled to a distal end of the implant and the implant is stored within the chamber in the first configuration and proximal of the exit opening. 
     Further optional features and variations of this eleventh embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the eleventh embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The pushrod and the implant can have a common travel direction through the exit opening such that the implant is drawn toward and through the exit opening by the pushrod as the pushrod is advanced toward and through the exit opening. 
     The apparatus can further comprise a guide proximal of the exit opening for facilitating compression of the implant from the first configuration to the second configuration as the pushrod is advanced toward and through the exit opening. 
     The pushrod can be stored within the chamber. 
     The chamber can be generally shaped like a ring. 
     The pushrod can be partially located exteriorly of the storage unit to expose a length of the pushrod for gripping and can enter the storage unit near a distal end of the storage unit. 
     The implant can comprise an occluding implant. 
     The implant can comprise a bioresorbable implant. 
     A twelfth embodiment comprises a method for introducing an implant into a hollow anatomical structure. The method can comprise the following acts, in any feasible order: (a) inserting an introducer sheath into the hollow anatomical structure; (b) coupling a delivery apparatus to a proximal end of the introducer sheath, the delivery apparatus storing a vascular implant in an expanded condition, proximally of an exit opening of the delivery apparatus; and (c) compressing the implant to a size sufficient to fit through the exit opening while distally advancing the implant through the exit opening and into the introducer sheath. 
     Further optional features and variations of this twelfth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twelfth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant can comprise an occluding implant. 
     Compressing the implant can further comprise compressing the implant to a size sufficient to fit in the introducer sheath. 
     Distally advancing the implant can comprise distally advancing a pushrod coupled to the implant. For example, distally advancing the implant can comprise gripping an exposed portion of the pushrod proximal of the converged pushrod and implant. 
     Distally advancing the implant through the exit opening can cause the compression of the implant. 
     The method can further comprise expanding the implant after distally advancing the implant into the hollow anatomical structure. For example, expanding the implant can comprise withdrawing the introducer sheath and allowing the implant to self-expand. 
     The implant can be radially larger than the exit opening in the expanded condition. 
     The hollow anatomical structure can comprise a blood vessel. The method can further comprise occluding a lumen of the blood vessel with the implant. The implant can be bioresorbable. 
     The hollow anatomical structure can comprise a vein in a leg. 
     A thirteenth embodiment comprises an elongate vascular implant for a hollow anatomical structure. The implant comprises a body formed by a number of generally parallel, longitudinally extending elongate fibers and having a distal end, multiple spaced bands coupled to and encircling the body, and a tether coupled with respect to the body and interacting with the bands to form multiple force application points acting on the body such that application of a proximal force to the tether causes the distance between the bands to decrease and the body to shorten and one of expand radially between the bands and increase in density between the bands. 
     Further optional features and variations of this thirteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the thirteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     At least one of the body, the bands, and the tether can comprise a bioresorbable material. 
     The body can be elastic and the tether can be inelastic. For example, the tether can comprise an inelastic yarn. 
     The tether can be coupled to a distal end of the body. 
     The implant can further comprise an adjustably-sized loop passing through or coupled to the bands and coupled to or formed by the tether, such that applying a proximal force to the tether reduces the size of the loop and relatively draws the bands toward each other to decrease the distance between the bands. For example, the multiple spaced bands can comprise a proximal band and a distal band spaced distally from the proximal band, and the tether can sequentially extend from the body through the proximal band, reverse direction a first time and extend through the distal band, and reverse direction a second time to form the loop with the tether. 
     An apparatus for introducing an implant into a hollow anatomical structure can comprise the elongate vascular implant and a pushrod coupled to the implant, such that proximal movement of the implant is prevented by the pushrod when a proximal force is applied to the tether. A distal end of the pushrod can be coupled to the distal end of the implant. 
     A fourteenth embodiment comprises an elongate vascular implant for a hollow anatomical structure. The implant comprises a body formed by a number of generally parallel, longitudinally extending elongate fibers, multiple force application points coupled to the body, an adjustably-sized loop passing through or coupled to the force application points, and a tether, the loop being coupled to or formed by the tether. Application of a proximal force to the tether causes the loop to reduce in size, which relatively draws the force application points toward each other to shorten the body and one of expand radially the body between the force application points and increase the density of the body between the force application points. 
     Further optional features and variations of this fourteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the fourteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     At least one of the body, the force application points, and the tether comprises a bioresorbable material. 
     The body can be elastic and the tether can be inelastic. For example, the tether can comprise an inelastic yarn. 
     The tether can be coupled to a distal end of the body. 
     An apparatus for introducing an implant into a hollow anatomical structure can comprise the elongate vascular implant and pushrod coupled to the implant, such that proximal movement of the implant is prevented by the pushrod when a proximal force is applied to the tether. A distal end of the pushrod can be coupled to a distal end of the implant. 
     A fifteenth embodiment comprises a method for treating a vein. The method can comprise the following acts, in any feasible order: (a) inserting an implant through an introducer sheath into the vein, the implant having a body and multiple spaced bands coupled to and encircling the body; (b) expanding the implant from a compressed condition to an expanded condition in the vein; and (c) moving the bands relative to each other with the implant in the expanded condition to shorten the body between the bands and one of further expand radially between the bands and increase in density between the bands. 
     Further optional features and variations of this fifteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the fifteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     Inserting the implant through the introducer sheath can comprise compressing the implant from the expanded condition to the compressed condition. 
     Inserting the implant through the introducer sheath can comprise distally advancing a pushrod coupled with the implant through the introducer sheath. The method can further comprise preventing proximal movement of the implant with the pushrod during shortening of the body. 
     Expanding the implant can comprise withdrawing the introducer sheath from the implant within the vein. 
     Moving the bands relative to each other can comprise applying a proximal force to a tether coupled with respect to the body and interacting with the bands. 
     Shortening the body can comprise shortening a distal portion of the body. The vein can comprise the saphenous vein, and shortening the distal portion of the body can occur in a portion of the saphenous vein nearest the sapheno-femoral junction. 
     A sixteenth embodiment comprises an apparatus for delivering an implant. The apparatus comprises a pushrod stored in the apparatus, the pushrod having a distal tip; and an elongate vascular implant stored in the apparatus, the implant being connected to the pushrod near the distal tip of the pushrod. The pushrod is stored in the apparatus generally in a loop configuration. The implant is stored in the apparatus alongside the pushrod so that the implant extends and curves along and next to the loop formed by the pushrod. 
     Further optional features and variations of this sixteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the sixteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant can generally conform to the shape of the loop as it extends and curves along the loop. 
     The apparatus can further comprise a casing generally shaped like a ring which contains the stored pushrod and implant. The ring can generally conform to the pushrod loop and implant, and the casing can form a radially inward deflection from the ring configuration to expose a portion of the pushrod for gripping. The pushrod and the implant can diverge at distal portions thereof so that the pushrod exits the casing to expose a length of the pushrod for gripping. 
     The apparatus can further comprise a distal exit opening, and a pushrod passage receiving the pushrod and located proximal of the distal exit opening, wherein the pushrod passage and the distal exit opening are located on a delivery path. A portion of the implant can be positioned at a first location on the delivery path, and the implant can extend from the first location in a direction divergent from the delivery path. 
     The apparatus can further comprise an inward-tapering channel located distal of the pushrod distal tip and aligned therewith, such that a distal movement of the pushrod advances the pushrod tip, and draws the implant, through the inward-tapering channel while the channel compresses the implant. 
     The apparatus can further comprise a distal exit opening, wherein the distal tip of the pushrod is aligned with and proximal of the exit opening so that a distal movement of the pushrod effects a distal advancement of both the pushrod and implant toward and through the exit opening. 
     The implant can be radially self-expanding, and be stored in the apparatus in an expanded state. 
     The pushrod can be stored in a pushrod housing, and the implant can be stored next to but outside of the pushrod housing. 
     The implant can be a bioabsorbable occluder. 
     A seventeenth embodiment comprises an apparatus for delivering an implant into a patient via a catheter. The apparatus comprises an exit opening configured for juxtaposition and communication with the catheter; a pushrod contained in the apparatus, the pushrod having a distal tip; and an elongate vascular implant contained in the apparatus. The implant is connected to the pushrod near the distal tip of the pushrod. The pushrod is contained in the apparatus generally in a loop configuration. The implant is contained in the apparatus alongside the pushrod so that the implant extends and curves along and next to the loop formed by the pushrod. The distal tip of the pushrod is aligned with the exit opening such that a distal advancement of the pushrod causes the distal tip to pass through the exit opening and the implant to be drawn through the exit opening along with the pushrod. 
     Further optional features and variations of this seventeenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the seventeenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant can generally conform to the shape of the loop as it extends and curves along the loop. 
     The apparatus can further comprise a casing generally shaped like a ring which contains the stored pushrod and implant. The ring can optionally generally conform to the pushrod loop and implant, and the casing can optionally form a radially inward deflection from the ring configuration to expose a portion of the pushrod for gripping. The pushrod and the implant can optionally diverge at distal portions thereof so that the pushrod exits the casing to expose a length of the pushrod for gripping. 
     The apparatus can further comprise the catheter, and the catheter can be coupled with respect to, and in communication with, the exit opening such that the pushrod and implant pass into a lumen of the catheter upon distal advancement of the pushrod. 
     The implant can be radially self-expanding, and is stored in the apparatus in an expanded state. The apparatus can optionally further comprise an inward-tapering channel located proximal of the exit opening and aligned therewith, such that a distal movement of the pushrod advances the pushrod tip, and draws the implant, through the inward-tapering channel while the channel compresses the implant. 
     The pushrod can be stored in a pushrod housing, and the implant can be stored next to but outside of the pushrod housing. 
     The implant can be a bioabsorbable occluder. 
     An eighteenth embodiment comprises a method. The method comprises holding a pushrod in a loop configuration; holding a self-expanding elongate vascular implant in an expanded state, alongside the pushrod in a curved configuration that conforms generally to the loop; receiving a distal tip of the pushrod together with a distal portion of the implant in an inward-tapering channel and compressing the implant with the channel as the pushrod advances into the channel and draws the implant through the channel; and conducting the pushrod and compressed implant with a lumen of a catheter in a distal direction beyond the channel. 
     Further optional features and variations of this eighteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the eighteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     In the method, conducting the implant can comprise conducting the implant toward a blood vessel lumen. In the method, conducting the implant can comprise conducting the implant toward a vein lumen. 
     In the method, holding the pushrod and implant can comprise holding the pushrod and implant in a casing generally shaped like a ring. 
     In the method, holding the pushrod can comprise holding the distal tip of the pushrod in a position aligned with the channel such that distal advancement of the pushrod causes the distal tip to enter the channel. 
     A nineteenth embodiment comprises an apparatus for advancing a vascular implant into a blood vessel. The apparatus comprises a first elongate member, the first elongate member having sufficient column strength to function as a pusher member; and a second elongate member, the second elongate member being thinner than the first elongate member and extending to a distal end located at a first point which is at or near a distal end of the first elongate member. The elongate members form an implant retaining portion while the distal end of the second elongate member is located at the first point, the implant retaining portion being located proximal of the first point. The implant retaining portion comprising a space located between the elongate members and configured for receiving an implant portion, with the first elongate member on one side of the space and the second elongate member on another side. The implant retaining portion further comprises a proximal side and a distal side which further circumscribe the space, the proximal and distal sides being effective to prevent an implant received in the retaining portion from moving out of engagement with the retaining portion as the first elongate member is moved distally and proximally. The implant retaining portion is removable by withdrawing the second elongate member in a proximal direction with respect to the first elongate member, thereby moving the distal end of the elongate member proximally beyond the former location of the implant retaining portion. 
     Further optional features and variations of this nineteenth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the nineteenth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The apparatus can further comprise an elongate vascular implant having a distal portion retained within the retaining portion. The elongate vascular implant can optionally extend proximally from the implant retaining portion. The implant retaining portion can optionally grip the implant sufficiently to permit the first elongate member to push and pull the implant through a confined space. 
     The second elongate member can be not configured for tissue penetration. 
     The second elongate member can extend proximally beyond a proximal end of the first elongate member. The implant retaining portion can optionally be removable by manipulating a proximal portion of the second elongate member that extends proximally beyond the proximal end of the first elongate member. The implant retaining portion can optionally be removable by distally pulling a proximal portion of the second elongate member that extends proximally beyond the proximal end of the first elongate member, to withdraw the distal end of the second elongate member proximally from the first point. 
     The first elongate member can comprise a pushrod having an internal lumen that receives the second elongate member. The second elongate member can optionally extend proximally from the first point, pass radially outward of the pushrod to form the implant retaining portion, and then radially inward into the pushrod lumen proximal of the implant retaining portion, and then proximally within the pushrod lumen toward a proximal end of the pushrod. A distal portion of the second elongate member can be within the pushrod lumen, proximal of the former location of the implant retaining portion, when the implant retaining portion is removed. The second elongate member can optionally extend proximally from the first point, and be substantially straight as it extends through and forms the implant retaining portion, and then extend proximally within the pushrod lumen toward a proximal end of the pushrod. 
     The first elongate member can have an insertable shaft portion with a maximum radial profile that defines a circle, and the radial profile can define the outermost radial extent of the apparatus along the insertable length of the apparatus when the implant retaining portion is removed. 
     The second elongate member can be metallic. 
     The implant retaining portion can be located at a sidewall opening of the first elongate member, and the sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the first elongate member. 
     The second elongate member can be removably connected to the first elongate member at the first point. 
     A twentieth embodiment comprises an apparatus. The apparatus comprises an elongate rod sized for insertion into a blood vessel lumen, the rod having a distal end, at least one sidewall opening near the distal end and an internal lumen extending proximally of the sidewall opening; an elongate member positioned in the rod and extending to an elongate member endpoint at or near the distal end of the rod; and an implant grip located proximal of the elongate member endpoint and comprising a space between the rod and the elongate member that is bounded on at least four sides thereof and is configured to prevent disengagement of an implant portion secured in the space when the rod is moved distally and proximally within a constraining lumen. The elongate member extends proximally within the lumen of the rod, proximal of the implant grip. The implant grip can be removable by withdrawing the elongate member in a proximal direction with respect to the rod, thereby moving the distal end of the elongate member proximally beyond the former location of the implant grip. 
     Further optional features and variations of this twentieth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twentieth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The implant grip can be formed at least in part by a portion of the elongate member that extends radially outward from the elongate rod via the sidewall opening. 
     The apparatus can further comprise an elongate vascular implant having a distal portion gripped by the implant grip. The elongate vascular implant can optionally extend proximally from the implant grip. 
     The implant grip can grip the implant sufficiently to permit the elongate rod to push and pull the implant through a confined space. 
     The elongate member can be not configured for tissue penetration. 
     The elongate member can extend proximally beyond a proximal end of the elongate rod. The implant grip can optionally be removable by manipulating a proximal portion of the elongate member that extends proximally beyond the proximal end of the elongate rod. The implant grip can optionally be removable by distally pulling a proximal portion of the elongate member that extends proximally beyond the proximal end of the elongate rod, to withdraw the distal end of the elongate proximally. 
     The elongate member can extend proximally from the elongate member endpoint, pass radially outward of the elongate rod to form the implant grip, and then radially inward into the elongate rod lumen proximal of the implant grip, and then proximally within the elongate rod lumen toward a proximal end of the elongate rod. 
     A distal portion of the elongate member can be within the elongate rod lumen, proximal of the former location of the implant grip, when the implant grip is removed. 
     The elongate member can extend proximally from the elongate member endpoint, and be substantially straight as it extends through and forms the implant grip, and then extend proximally within the elongate rod lumen toward a proximal end of the elongate rod. 
     The elongate rod can have an insertable shaft portion with a maximum radial profile that defines a circle, and the radial profile can define the outermost radial extent of the apparatus along the insertable length of the apparatus when the implant grip is removed. 
     The elongate member can be metallic. 
     The sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the rod. 
     The elongate member can be removably connected to the rod at the elongate member endpoint. 
     A twenty-first embodiment comprises a method. The method comprises inserting an introducer sheath into a blood vessel; pushing an elongate, bioresorbable vascular implant into the vessel through the sheath via a pushrod. The pushrod holds the distal end of the implant in an implant grip formed on one side by the pushrod and on another side by a retractable elongate flexible member received within a lumen of the pushrod proximal of the implant grip and extending to a flexible member endpoint distal of the implant grip. The elongate flexible member passes through or along a sidewall opening of the pushrod as the flexible member extends from the pushrod lumen to the flexible member endpoint. The method further comprises releasing the implant from the pushrod by retracting the elongate flexible member proximally of the sidewall opening and into the lumen of the pushrod; and reducing the chance of snagging or displacing the portion of the implant positioned in the vessel when withdrawing the pushrod, by causing the pushrod to take on a maximum radial profile no larger than that of a proximal insertable shaft portion of the pushrod once the elongate flexible member has been withdrawn into the lumen of the pushrod. 
     Further optional features and variations of this twenty-first embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twenty-first embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The method can further comprise pulling a portion of the implant proximally with the pushrod and implant grip, after pushing the implant into the vessel but before releasing the implant from the implant grip. 
     The method can further comprise expanding or increasing the density of a distal portion of the implant by pulling the distal portion of the implant proximally with the pushrod and implant grip, after pushing the implant into the vessel but before releasing the implant from the implant grip. 
     The blood vessel can comprise a vein in a leg. The method can optionally further comprise occluding the vein with the implant. 
     The method can further comprise withdrawing the introducer sheath from the blood vessel while leaving the implant in position in the vessel. The method can optionally further comprise holding the implant in position in the vessel with the pushrod while withdrawing the sheath. The method can optionally further comprise allowing the implant to self-expand within the vessel by virtue of withdrawing the sheath. 
     The sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the pushrod. 
     The elongate flexible member can be removably connected to the pushrod at the flexible member endpoint, and releasing the implant can comprise disconnecting the flexible member from the pushrod. 
     A twenty-second embodiment comprises an apparatus for inserting an implant into a blood vessel. The apparatus comprises an elongate rod sized for insertion into a blood vessel lumen, the rod having a sidewall, a distal end, at least one sidewall opening near the distal end and an internal lumen extending proximally of the sidewall opening; and an elongate member positioned in the rod and extending to an elongate member endpoint located distal of the sidewall opening, the elongate member extending proximally along or through the sidewall opening and into the elongate rod lumen, proximally of the sidewall opening. The sidewall opening has an upper edge, and the sidewall opening extends into the rod to a first depth. The upper edge extends distally from the first depth while sloping upward so that the sidewall opening gradually becomes shallower as it extends distally, the upper edge thereby forming a distal slope. The sidewall opening is configured, by virtue of the distal slope, to gently urge outward from the opening any implant material located in the sidewall opening as the rod is retracted, thereby reducing snagging. 
     Further optional features and variations of this twenty-second embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twenty-second embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The apparatus can further comprise an elongate vascular implant with a portion received and secured between the rod and the elongate member. The received portion of the implant can optionally traverse from one side of the rod and elongate member through a space between the rod and elongate member to the other side of the rod and elongate member. The implant can optionally fowl two legs which extend proximally from the received portion of the implant. The implant can optionally comprise a bundle of bioresorbable fibers. The rod and the elongate member can optionally grip the fibers therebetween. The rod and the elongate member can optionally form an implant grip located proximal of the elongate member endpoint and comprising a space between the rod and the elongate member that is bounded on at least four sides thereof and is configured to prevent disengagement of the implant portion when the rod is moved distally and proximally within a constraining lumen. 
     The upper edge of the sidewall opening can extend proximally from the first depth while sloping upward so that the sidewall opening gradually becomes shallower as it extends proximally, the upper edge thereby forming a proximal slope. The sidewall opening can optionally be configured, by virtue of the proximal slope, to gently urge any material of the implant found to be in the sidewall opening outward therefrom as the rod is pushed distally with the apparatus in the release configuration. 
     The distal slope can be angled or curved. 
     The elongate member can extend radially outward from the sidewall opening and the rod to form an implant grip. The elongate member can optionally no longer extend radially outward from the sidewall opening and the rod when the apparatus is in the release configuration. 
     The rod can have an insertable shaft portion with a maximum radial profile that defines a circle, and said radial profile can define the outermost radial extent of the apparatus along the insertable length of the apparatus when the apparatus is in the release configuration. 
     The elongate member can be substantially straight as it extends from the elongate member endpoint to the elongate rod lumen proximal of the sidewall opening. 
     The sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the rod. 
     The elongate member can be removably connected to the rod at the elongate member endpoint. 
     A twenty-third embodiment comprises an apparatus. The apparatus comprises an elongate vascular implant; an elongate rod sized for insertion into a blood vessel lumen, the rod having a sidewall, a distal end, at least one sidewall opening near the distal end and an internal lumen extending proximally of the sidewall opening; and an elongate member positioned in the rod and extending to an elongate member endpoint located distal of the sidewall opening, the elongate member extending proximally along or through the sidewall opening and into the elongate rod lumen, proximally of the sidewall opening, the elongate member being retractable into the elongate rod lumen proximal of the sidewall opening to form a release configuration of the apparatus. The sidewall opening has an upper edge, and the sidewall opening extends into the rod to a first depth. The upper edge extends distally from the first depth while sloping upward so that the sidewall opening gradually becomes shallower as it extends distally, the upper edge thereby forming a distal slope. A portion of the implant is received and secured between the elongate rod and the elongate member. The sidewall opening is configured, by virtue of the distal slope, to gently urge any material of the implant found to be in the sidewall opening outward therefrom as the rod is retracted with the apparatus in the release configuration. 
     Further optional features and variations of this twenty-third embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twenty-third embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     The received portion of the implant can traverse from one side of the rod and elongate member through a space between the rod and elongate member to the other side of the rod and elongate member. The implant can optionally form two legs which extend proximally from the received portion of the implant. The implant can optionally comprise a bundle of bioresorbable fibers. The rod and the elongate member can optionally grip the fibers therebetween. 
     The upper edge of the sidewall opening can extend proximally from the first depth while sloping upward so that the sidewall opening gradually becomes shallower as it extends proximally, the upper edge thereby forming a proximal slope. The sidewall opening can optionally be configured, by virtue of the proximal slope, to gently urge any material of the implant found to be in the sidewall opening outward therefrom as the rod is pushed distally with the apparatus in the release configuration. 
     The distal slope can be angled or curved. 
     The elongate member can extend radially outward from the sidewall opening and the rod to form an implant grip. The elongate member can optionally no longer extend radially outward from the sidewall opening and the rod when the apparatus is in the release configuration. 
     The rod can have an insertable shaft portion with a maximum radial profile that defines a circle, and the radial profile can define the outermost radial extent of the apparatus along the insertable length of the apparatus when the apparatus is in the release configuration. 
     The elongate member can be substantially straight as it extends from the elongate member endpoint to the elongate rod lumen proximal of the sidewall opening. 
     The rod and the elongate member can form an implant grip located proximal of the elongate member endpoint and comprising a space between the rod and the elongate member that is bounded on at least four sides thereof and is configured to prevent disengagement of the implant portion when the rod is moved distally and proximally within a constraining lumen. 
     The sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the rod. 
     The elongate member can be removably connected to the rod at the elongate member endpoint. 
     A twenty-fourth embodiment comprises a method. The method comprises inserting an introducer sheath into a blood vessel; pushing an elongate, bioresorbable vascular implant into the vessel through the sheath via a pushrod. The pushrod holds the distal end of the implant in an implant grip formed on one side by the pushrod and on another side by a retractable elongate flexible member received within a lumen of the pushrod proximal of the implant grip and extending to a flexible member endpoint distal of the implant grip. The elongate flexible member passes through or along a sidewall opening of the pushrod as it extends from the pushrod lumen to the flexible member endpoint. The method further comprises releasing the implant from the pushrod by retracting the elongate flexible member proximally of the sidewall opening; and withdrawing the pushrod proximally from the portion of the implant positioned in the blood vessel while gently urging any implant material found to be in the sidewall opening outward therefrom. 
     Further optional features and variations of this twenty-fourth embodiment are presented in the following paragraphs. The present disclosure contemplates and includes employing these optional features and variations in the twenty-fourth embodiment (or in any other embodiment summarized or described herein), either alone or in any feasible combination of two or more such optional features and variations. 
     In the method, gently urging any implant material comprises doing so with a sloping portion of the sidewall opening. 
     The method can further comprise avoiding snagging or displacing the portion of the implant positioned in the vessel when withdrawing the pushrod by virtue of the gently urging. 
     The method can further comprise reducing the chance of snagging or displacing the portion of the implant positioned in the vessel when withdrawing the pushrod, by causing the pushrod to take on a maximum radial profile no larger than a proximal insertable shaft portion of the pushrod once the elongate flexible member has been drawn into the lumen of the pushrod. 
     The method can further comprise pulling a portion of the implant proximally with the pushrod and implant grip, after pushing the implant into the vessel but before releasing the implant from the implant grip. 
     The method can further comprise expanding or increasing the density of a distal portion of the implant by pulling the distal portion of the implant proximally with the pushrod and implant grip, after pushing the implant into the vessel but before releasing the implant from the implant grip. 
     In the method, the blood vessel can comprise a vein in a leg. The method can optionally further comprise occluding the vein with the implant. 
     The method can further comprise withdrawing the introducer sheath from the blood vessel while leaving the implant in position in the vessel. The method can optionally further comprise holding the implant in position in the vessel with the pushrod while withdrawing the sheath. The method can optionally further comprise allowing the implant to self-expand within the vessel by virtue of withdrawing the sheath. 
     In the method, the sidewall opening can face radially outward in a direction transverse to the longitudinal axis of the pushrod. 
     The elongate member can be removably connected to the pushrod at the flexible member endpoint, and releasing the implant can comprise disconnecting the flexible member from the pushrod. 
     Certain objects and advantages of the disclosed embodiments are described herein. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment. Thus, for example, an embodiment may be practiced or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. 
     Despite the foregoing discussion of certain embodiments, only the appended claims, and such other claims as may be presented in the future based on the disclosure herein (and not the present Summary), are intended to define the invention(s) protected hereby. The summarized embodiments, and other embodiments, are presented in the following detailed description having reference to the attached figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic view of a human leg and portions of the deep and superficial venous systems. 
         FIG. 2  is an elevation view of an embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 . 
         FIG. 3  is a perspective view of an exemplary introducer sheath according to one embodiment for facilitating introduction of the implant of  FIG. 2  into a hollow anatomical structure. 
         FIG. 4  is an elevation view of a system according to one embodiment comprising the introducer sheath of  FIG. 3  and an embodiment of an apparatus for storage and/or introduction of the implant of  FIG. 2 . 
         FIG. 5  is an elevation view identical to  FIG. 4  with the introducer sheath and an embodiment of a coupler assembly of the apparatus comprising proximal and distal couplers shown as exploded. 
         FIG. 6  is an enlarged view of the region labeled “VI” in  FIG. 5 . 
         FIG. 7  is an enlarged view of the region labeled “VII” in  FIG. 5 . 
         FIG. 8  is a sectional view of distal portions of the system of  FIG. 4  with an introducer of the apparatus in a storage position according to one embodiment. 
         FIG. 9  is a perspective view of  FIG. 8 . 
         FIG. 10  is a perspective view of the distal coupler of the coupler assembly of  FIG. 5 . 
         FIG. 11  is an enlarged sectional view of an embodiment of the introducer, particularly the proximal end of the introducer, of the apparatus of  FIG. 4 . 
         FIG. 12  is a sectional perspective view of the distal end of the introducer (in section) from  FIG. 11  and the implant of  FIG. 2  according to one embodiment. 
         FIG. 13  is a sectional view similar to  FIG. 8  with the introducer of the apparatus of  FIG. 4  in an advancing position according to one embodiment; the implant is not shown for clarity. 
         FIG. 14  is a perspective view of  FIG. 13 ; the implant is not shown for clarity. 
         FIGS. 15-24A  illustrate various exemplary stages of a method of use of the system according to one embodiment: 
         FIG. 15  illustrates the leg of  FIG. 1  with a shaft of the introducer sheath of  FIG. 3  located in the greater saphenous vein of the leg. 
         FIG. 15A  is an enlarged view of the region labeled “XV-A” in  FIG. 15 . 
         FIG. 16  is a view similar to  FIG. 15  with the distal coupler of the apparatus of  FIG. 5  mounted to the introducer sheath. 
         FIG. 17  is a view similar to  FIG. 16  with the apparatus of  FIG. 5  mounted to the distal coupler and introducer sheath. 
         FIG. 18  is a view similar to  FIG. 15A  with the introducer of  FIG. 11  and the implant of  FIG. 2  fully advanced into the introducer sheath in the greater saphenous vein. 
         FIG. 19  is a view similar to  FIG. 16  during removal of the apparatus from the distal coupler and the introducer sheath. 
         FIG. 20  is a view similar to  FIG. 19  after removal of the apparatus from the distal coupler and the introducer sheath and trimming of the implant. 
         FIG. 21  is a view similar to  FIG. 18  after removal of the distal coupler and the introducer sheath from the greater saphenous vein. 
         FIG. 22  is a view similar to  FIG. 19  illustrating release of the implant from the introducer. 
         FIG. 23  is a view similar to  FIG. 22  illustrating the implant in the greater saphenous vein after removal of the introducer from the greater saphenous vein. 
         FIG. 24  illustrates the leg after implantation of the implant in the greater saphenous vein. 
         FIG. 24A  is a plan view of the exterior region of the leg labeled “XXIV-A” in  FIG. 24 . 
         FIGS. 25A, 25B, and 25C  provide sectional views of a body of the implant of  FIG. 2  in storage, introduction, and implantation conditions, respectively. 
         FIG. 26  is an elevation view of a system according to another embodiment comprising the introducer sheath of  FIG. 3  and an embodiment of an apparatus for storage and/or introduction of the implant of  FIG. 2 . 
         FIG. 27  is an exploded view of the apparatus shown in  FIG. 26 . 
         FIG. 28  is a side view of a right housing shell of the apparatus. 
         FIG. 29  is a side view of a left housing shell of the apparatus. 
         FIG. 30  is perspective view of the apparatus shown in  FIG. 26 . 
         FIG. 31  is a sectional view of distal portions of the system of  FIG. 26  with an introducer of the apparatus in a storage position according to one embodiment. 
         FIG. 32  is a perspective view of  FIG. 31 . 
         FIG. 33  is a sectional view through line  33 - 33  of  FIG. 30 . 
         FIG. 34  is a sectional view through line  34 - 34  of  FIG. 30 , with only a portion of a pushrod is shown for clarity. 
         FIG. 35  is a sectional view through line  35 - 35  of  FIG. 26 . 
         FIG. 36  is a sectional view through line  36 - 36  of  FIG. 26 . 
         FIG. 37  is a sectional view similar to  FIG. 31  with the introducer of the apparatus of  FIG. 26  in an advancing position according to one embodiment; the implant is not shown for clarity. 
         FIG. 38  is a perspective view of  FIG. 37 ; the implant is not shown for clarity. 
         FIG. 39  illustrates the leg of  FIG. 1  with a shaft of the introducer sheath of  FIG. 3  located in the greater saphenous vein of the leg, the distal coupler of the apparatus of  FIG. 26  mounted to the introducer sheath, and the apparatus of  FIG. 26  mounted to the distal coupler and introducer sheath. 
         FIG. 40  is a view similar to  FIG. 39  during removal of the apparatus from the distal coupler and the introducer sheath. 
         FIG. 41  is a view similar to  FIG. 40  after removal of the apparatus from the distal coupler and the introducer sheath and trimming of the implant. 
         FIG. 42  is an elevation view of another embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 , showing the implant in an unaugmented configuration. 
         FIG. 43  is an elevation view of similar to  FIG. 42 , showing the implant in an augmented configuration. 
         FIG. 44  illustrates the leg of  FIG. 1  and the implant of  FIG. 42  located in the greater saphenous vein, with the implant in the unaugmented configuration. 
         FIG. 45  is a view similar to  FIG. 44  illustrating the implant in the augmented configuration. 
         FIG. 46  is an elevation view of another embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 , showing the implant in an unaugmented configuration. 
         FIG. 47  is an elevation view of similar to  FIG. 46 , showing the implant in an augmented configuration. 
         FIG. 48  is an elevation view of another embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 , showing the implant in an augmented configuration. 
         FIG. 49  is an elevation view of similar to  FIG. 48 , showing a first augmentation zone in an augmented configuration. 
         FIG. 50  is an elevation view of similar to  FIG. 49 , showing a second augmentation zone in an augmented configuration. 
         FIG. 51  is an elevation view of similar to  FIG. 50 , showing a third augmentation zone in an augmented configuration. 
         FIG. 52  is an elevation view of another embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 , showing the implant in an unaugmented configuration. 
         FIG. 53  is an elevation view of similar to  FIG. 52 , showing a first augmentation zone in an augmented configuration. 
         FIG. 54  is an elevation view of similar to  FIG. 53 , showing a second augmentation zone in an augmented configuration. 
         FIG. 55  is an elevation view of another embodiment of an implant for occluding a hollow anatomical structure, such as a vein in the venous systems shown in  FIG. 1 , showing the implant in an unaugmented configuration. 
         FIG. 56  is an elevation view of similar to  FIG. 55 , showing a first augmentation zone in an augmented configuration. 
         FIG. 57  is an elevation view of similar to  FIG. 56 , showing second augmentation zone in an augmented configuration. 
         FIG. 58  is an enlarged sectional view of another embodiment of an introducer, particularly the proximal end of the introducer. 
         FIG. 59  is an enlarged top view of the introducer from  FIG. 58 . 
         FIG. 60  is a sectional perspective view of the distal end of the introducer (in section) from  FIG. 58  and the implant of  FIG. 2  according to one embodiment. 
         FIG. 61  is a view similar to  FIG. 60  illustrating release of the implant from the introducer. 
         FIG. 62  is an enlarged sectional view of another embodiment of an introducer, particularly the proximal end of the introducer. 
         FIG. 63  is an enlarged top view of the introducer from  FIG. 62 . 
         FIG. 64  is a sectional perspective view of the distal end of the introducer (in section) from  FIG. 62  and the implant of  FIG. 2  according to one embodiment. 
         FIG. 65  is a view similar to  FIG. 64  illustrating release of the implant from the introducer. 
         FIG. 66  is an enlarged sectional view of another embodiment of an introducer, particularly the proximal end of the introducer. 
         FIG. 67  is an enlarged top view of the introducer from  FIG. 66 . 
         FIG. 68  is a sectional perspective view of the distal end of the introducer (in section) from  FIG. 66  and the implant of  FIG. 2  according to one embodiment. 
         FIG. 69  is a view similar to  FIG. 68  illustrating release of the implant from the introducer. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed embodiments relate generally to a method and apparatus for storage and/or introduction of an implant into a hollow anatomical structure (HAS). The term “hollow anatomical structure” is a broad term and is used in its ordinary sense, including, without limitation, veins, arteries, gastric structures, coronary structures, pulmonary structures, tubular structures associated with reproductive organs such as fallopian tubes, uteri, hollow organs and the like. Hollow anatomical structures particularly suited to treatment or occlusion by the methods and apparatuses of the disclosed embodiments include veins, such as veins of the lower extremities, for example, veins in the leg, and fallopian tubes. 
     Methods, systems, and apparatuses for occluding a hollow anatomical structure, such as the veins shown in  FIG. 1 , in a patient or subject using an implant such as occluding device or occluding material are disclosed. The terms “subject” and “patient” as used herein, refer to animals, such as mammals. For example, mammals contemplated by one skilled in the art include humans, primates, dogs, cats, sheep, cattle, goats, pigs, horses, mice, rats, rabbits, guinea pigs, and the like. The terms “subject” and “patient” are used interchangeably. 
     The terms “occluding device,” “occluding implant,” and “occluding material” as used herein are broad terms and are used in their ordinary sense, including, without limitation, a substance or device that is capable of occluding or causing occlusion of a HAS. Occluding materials or occluding devices can be formed or fabricated ex situ or formed in situ (e.g., by curing of a prepolymer or uncured polymer). The term “occluding material” as employed herein, includes prepolymers, uncured polymers, unsolidified materials, as well as occluding materials inserted into a patient in polymerized, procured, or solidified form. Biologic materials, e.g., gelatin and thrombin, can also be used separately or in combination with the occlusive materials. Bioresorbable materials are exemplary occluding materials, although other materials can also be used as desired. For example, in one embodiment, the occluding implant can include fibers and/or other components formed from polylactides (PLA) and/or polyglycolides (PGA) or copolymers thereof. 
     Occluding can include, but is not limited to, blocking by insertion of a plug or other structure into the HAS, such as any one or combination of the veins shown in  FIG. 1 , that prevents or inhibits flow therethrough, adhering opposite walls of the HAS together so as to prevent or inhibit flow therethrough, compressing the walls of the HAS together so as to prevent or inhibit flow therethrough, or initiating a physiological reaction to an applied force or substance (e.g., energy, chemicals, drugs, physical contact, pressure or the like) that causes flow through the HAS to be inhibited or prevented (e.g., formation of a fibrotic plug or growth of connective tissue). Occlusion can be immediate, or onset of occlusion can be delayed. Occlusion can be partial (i.e., permitting a reduced flow through the HAS) or complete (i.e., permitting no or substantially no flow through the HAS). Occlusion can be permanent or temporary. Occlusion can be affected by resorption characteristics of the material. Occlusion can result in physical change or damage to the HAS (e.g., tissue fibrosis or necrosis) or can block the HAS without substantial physical change (e.g., a biocompatible plug). The mechanisms by which occlusion can occur include but are not limited to formation of an organized fibrotic occlusion resulting from the body&#39;s natural foreign body healing response, formation of a wound or damage to tissue, expansion of the occluding device or occluding material, release of a chemical or bioactive agent (e.g., a sclerosant, inflammatory agent, cytokine, growth factor, clotting factor, tissue attachment factor, or other agent) from the occluding device or occluding material, venoconstriction, compression, and ligation. 
     Referring to  FIG. 2 , an implant  10  according to one embodiment for occlusion of a hollow anatomic structure comprises a bioresorbable body  12 . In one embodiment, the body  12  comprises a bioresorbable material in fibrous form, which can comprise a collection of individual fibers that can be spun into multi-filament yarns. The fibers or yarns can be textured to impart bulk. In one embodiment, multiple fibers or yarns can be assembled together to form the body  12 . The textured fibers or yarns can be made wavy to prevent adjacent yarns from lying closely together; some fibers or yarns may tangle together. The fibers can be treated and/or agglomerated in any suitable manner to achieve a desired texture, density, geometry, etc. The fibers can be made or treated such that the body  12  can be compressible and/or expandable. For example, as shown in the illustrated embodiment, the body  12  can naturally assume an expanded condition and convert to a compressed condition upon application of a compressive force. Alternatively, the body  12  can naturally assume a compressed condition and convert to an expanded condition upon application of an expansive force. The bioresorbable material can be any suitable bioresorbable material, such as a material from the family of alpha hydroxy acids, for example polylactide (PLA) and/or polyglycolide (PGA). 
     Suitable forms and materials for the bulked fibrous bioresorbable body (and/or individual yarns or fibers) are disclosed in U.S. Patent Application Publication No. 2006/0212127, published Sep. 21, 2006, and entitled, “Structures for Permanent Occlusion of a Hollow Anatomical Structure,” and in U.S. Patent Application Publication No. 2007/0248640, published Oct. 25, 2007, and entitled, “Occlusive Implant and Methods for Hollow Anatomical Structure.” Of those publications, the following is incorporated herein by reference: paragraphs 0010-0171 of Publication No. 2007/0248640 and the drawings referenced in those paragraphs. 
     In the embodiment of  FIG. 2 , the implant further includes a tether  14  coupled to the body  12 . As one example, the body  12  can be generally elongated with a distal end  16  and a proximal end  18 , the distance between the distal end  16  and the proximal end  18  (i.e., the length of the body  12 ) optionally being greater than the cross-sectional diameter of the body  12 , and the tether  14  is coupled near or to the distal end  16  of the body  12 . The tether  14  can be coupled to the body  12  in any suitable manner, examples of which include tying or stitching the tether  14  to the body  12 , employing a coupling agent, such as a bioresorbable or non-bioresorbable adhesive, and making the tether  14  integral with the body  12 . In the embodiment of  FIG. 2 , the tether  14  is coupled to the body  12  by tying the tether  14  around the body  12  near a center of the length of the body  12 , and the body  12  is bent or turned where the tether  14  is coupled to the body  12  such that the body  12  is folded upon itself. As a result of this configuration, the coupling location of the tether  14  forms the distal end  16  of the body  12 , and the free ends of the body  12  folded upon each other form the proximal end  18  of the body  12 . The tether  14  can have any suitable length relative to the length of the body  12 . For example, the length of the tether  14  can be greater than, equal to, or less than that of the body  12 . 
     The tether  14  can be bioresorbable and made of the same material as the body  12  or of a material different than that of the body  12 . Alternatively, the tether  14  can be non-bioresorbable. Further, the tether  14  can be inelastic or elastic. In the illustrated embodiment of  FIG. 2 , the tether  14  is made of the same bioresorbable material as the body  12 ; the body  12  comprises multiple fibers processed and textured such that the body  12  is bulked, elastic, and compressible, and the tether  14  comprises multiple fibers spun into a single, relatively smooth, and inelastic yarn, wherein the cross-sectional diameter of the body  12  in its natural expanded condition is significantly greater than the cross-sectional diameter of the tether  14 . 
     The implant  10  can be positioned in a HAS to occlude the HAS such that blood flow through the HAS is reduced or prevented. While the implant  10  can be positioned in the HAS in any suitable manner, such as the manners disclosed in the above-incorporated material from a patent application publication, additional or alternative techniques and/or apparatus can be employed, as discussed herein. 
     In one embodiment, the implant body  12  has an overall linear mass density of 7200 denier, and is formed from 48 plies of 75 denier, 30 filament, 100% polyglycolide (PGA) yarns. The PGA material has a molecular weight (Mn) over 12,750 and a polydispersity (PDI) between 1.1 and 1.8. A 30 cm length of the collected 48 plies has a breaking load between 30 and 50 lbf. Among the 48 plies, 24 are “S” twisted and 24 are “Z” twisted, all with a false twist texture of 90 twists per inch. The yarns are false twisted individually using pin twist texturing. The 48 plies are doubled over once at the distal end  16  of the body  12  to create a 7200 denier implant body  12 . The tether  14  is formed from 16 plies of 75 denier, 30 filament, 100% polyglycolide (PGA) yarns. The filament denier is 2.5, or about 2.5. All 16 plies are “Z” twisted between 3 and 4 twists per inch and heat set. A 40 cm length of the collected 16 plies has a breaking load between 10 and 17 lbf. 
     The 48-ply yarn is preferably cleaned by passing it in “reel to reel” fashion through an ultrasonic cleaning bath filled with ≧99% isopropyl alcohol at a temperature maintained below 85 degrees Fahrenheit. The alcohol is replaced at a rate sufficient to clean no more than 100 grams of yarn per gallon of alcohol. After the cleaning bath the yarn is dried by running it past one or more drying air jets. 
     After cleaning and drying, the yarn can be further bulked by heating. From a supply reel, the yarn is passed through a roller set and then downward in a generally vertical orientation from the roller set, and through a vertically oriented cylindrical heating chamber positioned below the roller set. A takeup reel positioned below and to the side of the lower end of the heating chamber takes up the yarn after it moves through and past the heating chamber. The roller set above the heating chamber pulls the yarn from the supply reel and pushes it downward through the heating chamber. The takeup reel is driven at a speed or speeds that leave the yarn fairly slack between the roller set and the takeup reel, and the yarn passes through the heating chamber in this slack condition so that the filaments separate somewhat for heating. The heating chamber is 4 inches long and 2 inches in inside diameter and the yarn is fed into the heating chamber at a feed speed of 0.0124 meters per second. The heating chamber heats the passing yarn with a circumferential hot air flow directed inwardly at the yarn, which travels approximately along the central vertical axis of the chamber. Air is flowed at a pressure of 60 PSI (+/−5 PSI) through a heater operated at a temperature of 250-350 degrees Fahrenheit, preferably 275 degrees. The heated, pressurized air then flows into the chamber via a circumferential opening or “slit” formed in the chamber inner wall. The temperature inside the chamber, measured at the chamber inner wall next to the circumferential slit (and the incoming airflow) is 155-165 degrees Fahrenheit. The circumferential arrangement of the hot air inflow helps to prevent asymmetric inward airflows which can tend to blow the yarn off-axis and induce tension in the yarn and thereby disrupt the bulking. 
     The dried and heat-bulked yarn can then be cut to the appropriate length (preferably 50 cm) and the tether  14  is tied to the midpoint. The two halves of the yarn are folded against each other to form the implant body  12  with the tether  14  tied at the distal end of the body  12 . 
     The above specified parameters for the implant body  12  and tether  14  can be varied or disregarded in other embodiments. The implant body  12  can have a linear mass density between 6000 and 8000, or between 4000 and 10,000. Between 60 and 120, or between 40 and 140, or between 20 and 200 twists per inch can be employed in texturing the plies/fibers/filaments of the implant body  12 . The number and size of the plies can be varied, or a single ply can be employed. Where multiple plies are employed in the body  12 , half can be “S” twisted and half can be “Z” twisted. Bioabsorbable materials other than PGA, such as polylactic acid (PLA), or any other suitable bioabsorbable or bioresorbable material specified herein can be employed, either alone or in combination with other such materials. For example, a mixture of PGA and PLA plies/fibers/filaments can be used. Non-bioabsorbable or non-bioresorbable materials can be employed as well. The filament denier in the body  12  can vary between 1.5 and 3.5, or between 0.5 and 5.0, while the filament count can vary between 2000 and 4000, or between 1000 and 5000, or otherwise to fall within the above specified ranges for linear mass density. Where PGA is used in forming the body  12 , the molecular weight (Mn) can vary between 10,000 and 15,000, or between 5,000 and 20,000. 
       FIG. 3  illustrates an exemplary embodiment of an introducer sheath  20  that can be used to facilitate introduction of an implant, such as the implant  10  in  FIG. 2  or other suitable implant, into a HAS. The introducer sheath  20  can be any suitable device configured for insertion into the HAS and for introduction of the implant  10  into the HAS; many varieties of introducer sheaths are commercially available and known to one skilled in the art. On example of an introducer sheath  20  is disclosed in U.S. Pat. No. 5,897,497, issued Apr. 27, 1999, and entitled “Guiding Catheter Introducer Assembly.” The depicted introducer sheath  20  in  FIG. 3  is provided for illustrative purposes and is not intended to limit the present disclosure in any manner. 
     The illustrated introducer sheath  20  has a tubular and flexible shaft  22  with a lumen  24  and, at its distal end, a protective distal tip portion  26 . The sheath  20  further includes a hub  28  attached to a proximal end of the shaft  22  and having a pair of annular shoulders, a proximal shoulder  30  and a distal shoulder  32 . The hub  28  also comprises a proximal opening  34  generally aligned with and in communication with the lumen  24  at the proximal end of the shaft  22 , a distal rotatable frustoconical sleeve  36  that includes the distal shoulder  32  and a radially extending anchoring flange  38 , and a side port  40  extending radially from the hub  28  between the shoulders  30 ,  32 . A sidearm  42  connected to the side port  40  of the hub  28  terminates at a fluid fitting  44  to facilitate introduction of fluids through the sidearm  42  and into the side port  40 . In the depicted embodiment, the hub  28  is configured for fluid communication between the side port  40  and the shaft  22  such that a fluid introduced into the fluid fitting  44  can flow into the lumen  24  of the shaft  22 . The sheath  20  can be sized for insertion into a HAS; as an example, the shaft  22  of the sheath  20  can have an outer diameter of about 1-5 mm. Another example of the introducer sheath  20  is an 8F sheath having a length of about 55 cm. 
     Referring now to  FIG. 4 , the introducer sheath  20  can be included in a system  46  with the implant  10  of  FIG. 2 , or other suitable implant, and an apparatus  50  configured for storing and/or surgically introducing the implant  10  into a HAS. The depicted apparatus  50  comprises an implant storage unit  52  adapted to store the implant  10  prior to and during introduction of the implant  10  into the HAS, a coupler assembly  54  configured to couple the apparatus  50  to the introducer sheath  20 , and an introducer assembly  56  that, when manipulated by the practitioner manually or through the operation of a motorized drive system, or through a manually operated gear train or other mechanism, feeds the implant from the implant storage unit  52 , through the coupler assembly  54 , and into the introducer sheath  20  for placement of the implant  10  in the HAS. In  FIG. 5 , the coupler assembly  54  of the apparatus  50  is illustrated as exploded to facilitate viewing the relative positioning of the introducer sheath  22  and the apparatus  50 . 
     With continued reference to  FIG. 5 , the implant storage unit  52  of the depicted embodiment comprises a generally cylindrical tube  60  sized to accommodate the implant  10 , as will be discussed in further detail below, and having a lumen  62  extending between the tube proximal and distal ends. An end cap  64  closes the proximal end of the tube  60 , and the coupler assembly  54  receives the open distal end of the tube  60 , as will be described in more detail below. The exemplary end cap  64  (see  FIG. 6 ) has a closure wall  66  oriented generally perpendicular to the longitudinal axis of the tube  60 , a generally cylindrical body  68  extending axially within the tube  60 , and an annular flange  70  surrounding the closure wall  66  and abutting the proximal end of the tube  60 . The tube  60  and corresponding end cap  64  can be generally cylindrical, as described above and shown in  FIGS. 4 and 5 , and other configurations are contemplated, including tubes and end caps having triangular, rectangular, and square cross-sectional shapes. The tube  60  and end cap  64  can have any suitable configuration and are not limited to the geometries described herein and illustrated in the figures. 
     As shown in  FIG. 6 , which is an enlarged view of the region labeled “VI” in  FIG. 5 , the end cap  64  can optionally function as an anchor for the implant  10  stored within the tube  60 . Anchoring of the implant  10  inhibits bunching of the implant body  12  toward the distal end of the tube  60  and tangling of the tether  14 . The end cap  64  can anchor the implant  10  in any desired manner, and, in the illustrated embodiment, the proximal end  18  of the implant body  12  and the proximal end of the tether  14  are positioned or sandwiched between the end cap body  68  and the side wall of the tube  60 . The relative dimensions of the end cap body  68  and the tube  60  provide sufficient clearance for the body  12  and the tether  14  while applying a compressive force thereto to thereby retain the body  12  and the tether  14  at the proximal end of the tube  60 . Optionally, a portion of the body  12  and/or the tether  14  can extend out the tube  60  between the flange  70  and the proximal end of the tube  60 . Alternative methods of anchoring the implant  10  include, but are not limited to, employing an adhesive between the implant  10  and the end cap  64  and/or the tube  60 . Further, the implant  10  can be anchored by the body  12 , the tether  14 , or both the body  12  and the tether  14 . 
     Referring now to  FIGS. 7 and 8 , which is an enlarged view of the region labeled “VII” in  FIG. 5 , the depicted coupler assembly  54  that couples the apparatus  50  to the introducer sheath  20  comprises mating proximal and distal couplers  80 ,  82 . The proximal coupler  80  includes a tubular conduit  84  having a storage portion  86  and a coupling portion  88 . In the depicted embodiment, the storage portion  86  and the coupling portion  88  are oriented at an obtuse angle α relative to each other. As an example, the angle α can be about 150 degrees; other examples of the angle α include 0-180 degrees. As best viewed in the sectional view of  FIG. 8  and the perspective view of the same region in  FIG. 9 , the storage portion  86  aligns axially with the tube  60  and receives the distal end of the tube  60  to thereby connect the tube  60  and the storage portion  86  of the proximal coupler  80 . The tube  60  and the proximal coupler  80  can be joined in any suitable fashion, such as, for example, an interference fit, with an adhesive, a snap fit, etc. An aperture  90  formed through a side wall of the storage portion  86  is aligned and can be generally collinear with the longitudinal axis of the coupling portion  88  and, when the system  46  is assembled, the proximal opening  30  of the hub  28  and the lumen  24  of the introducer sheath shaft  22 . 
     As shown in  FIGS. 8 and 9 , the coupling portion  88  houses an insert  92  having an introducer guide  94  in the form of a frustoconical wall that tapers distally and terminates at a duct  96  defining a channel  98  having an exit opening  100  surrounded by an annular distal face  102 . The channel  98  and the exit opening  100  are oriented in axial alignment with the aperture  90  in the storage portion  86 . The insert  92  further comprises a pair of opposing bayonet fitting keyways  104  formed in an outer wall  106  generally coaxial with the duct  96  and extending from the introducer guide  94  to a distal face  108  generally coplanar with the duct distal face  102 . The insert  92  can be secured to the coupling portion  88  in any suitable fashion, such as, for example, an interference fit, with an adhesive, a snap fit, etc.; alternatively, the insert  92  or the features of the insert  92  can be integrally formed with the coupling portion  88 . 
     While the proximal coupler  80  has been described as comprising the tubular conduit  84  having the storage portion  86  and the coupling portion  88  that houses the insert  92 , the proximal coupler  80  can alternatively be considered as comprising only the insert  92 , which performs a coupling function, with the tubular conduit  84 , which performs a storage function, considered as an extension or part of the implant storage unit  52 . Regardless, the exit opening  100  functions as an exit opening for the implant storage unit  52  and the overall apparatus  50  as the implant  10  exits the implant storage unit  52  and the apparatus  50  through the exit opening  100 . The tubular conduit  84  and the insert  92  can be constructed in any desired manner with either or both parts functioning to partially store the implant  10  and/or couple the apparatus  50  to the introducer sheath  20 . 
     Referring now to  FIG. 10 , the depicted embodiment of the coupler assembly distal coupler  82  comprises a distal generally cylindrical body  110 , a proximal generally cylindrical body  112 , and a distally tapering frustoconical flange  114  therebetween. The distal body  110  and the frustoconical flange  114  can optionally include a grip  116 , such as a grip  116  in the form of a plurality of grooves, to facilitate manipulation of the distal coupler  82  by the practitioner. While the distal and proximal bodies  110 ,  112  can have any suitable relative dimensions, the distal body  110  of the illustrated embodiment is longer than and has a smaller cross-sectional diameter than the proximal body  112 . The proximal body  112  is sized for insertion into and receipt by the proximal coupler  80  of the coupler assembly  54 , particularly the insert  92  of the proximal coupler  80 , and includes a pair of opposing keys  118  configured for receipt and sliding movement in the bayonet fitting keyways  104  of the insert  92  (see  FIGS. 8 and 9  for relationship between the proximal body  112  and the insert  92 ). The proximal body  112  and the frustoconical flange  114  meet at a proximally-facing annular surface  120 . 
     With continued reference to  FIG. 10 , the distal coupler  80  includes an elongated slot  122  extending the entire length of the distal coupler  80  and providing access to a central bore  124 . The slot  122  comprises a first portion  126  sized at least for receipt of the shaft  22  of the introducer sheath  20  and a second portion  128  sized at least for receipt of the side port  40  of the introducer sheath  20 . In the illustrated embodiment, the first and second portions  126 ,  128  are sized to receive the shaft  22  and the side port  40  such that the shaft  22  and the side port  40  have limited lateral movement within the slot  122 . Referring back to  FIGS. 8 and 9 , the bore  124  has three coaxial sections, first, second, and third sections  130 ,  132 ,  134 , that increase proximally in cross-sectional area relative to each other. The first section  130  is sized for receipt of the shaft  22  of the introducer sheath  20 , the second section  132  is sized for receipt of the sleeve  36  on the hub  28  of the introducer sheath  20 , and the third section  134  is sized for receipt of the remaining portion of the hub  28  and of the duct  96  of the proximal coupler  80 . The first and second sections  130 ,  132  join at a frustoconical wall  136 ; the frustoconical wall  136  and the first section  130  are coincident with the first portion  126  of the slot  122 . The second and third sections  132 ,  134  meet at a proximally-facing stop  138 . 
     The proximal and distal couplers  80 ,  82  of the coupler assembly  54  can be connected together, as shown in  FIGS. 8 and 9 , to couple the apparatus  50  to the introducer sheath  20 . In the coupled condition, the proximal and distal couplers  80 ,  82  retain the hub  28  of the introducer sheath  20  therebetween. In particular, the proximal end of the hub  28  abuts the duct distal face  102  of the proximal coupler  80 , and the distal shoulder  32  of the hub  28  abuts the stop  138  of the distal coupler  82 . Consequently, the aperture  90  and the channel  98  defined by the duct  96  of the proximal coupler  80  align axially with the proximal opening  34  of the hub  28  and, thereby, the lumen  24  at the proximal end of the shaft  22 . The slot  122  of the distal coupler  82  accommodates the radially extending components of the hub  28 , particularly the retaining flange  38  and the side port  40 , which is connected to the sidearm  44  seen in  FIG. 9 . To retain the coupler assembly  54  in the coupled condition, the proximal coupler keyways  104  receive the distal coupler keys  118  in a known bayonet fitting fashion, and the proximally-facing annular surface  120  between the proximal body  112  and the frustoconical flange  114  of the distal coupler  82  abuts the distal face  108  of the proximal coupler  80 . 
     Referring back to  FIG. 4 , the depicted embodiment of the introducer assembly  56  of the apparatus  50  comprises an introducer or pushrod  150  partially stored within a tubular casing  152  mounted to the tube  60  of the implant storage unit  52  via brackets  154 . The brackets  154  can be mounted to an exterior wall of the tube  60 ; alternatively, the brackets  154  can join adjacent segments that form the tube  60 , whereby the brackets  154  can themselves form part of the tube  60 . The length of the casing  152  is sufficient to encase the proximal end of the pushrod  150  prior to use of the apparatus  50  for delivery of the implant  10 . Further, the casing  152  can be coiled one or more times to accommodate the length of the pushrod  150  and, thereby, maintain a relatively compact configuration for the assembly  50 . The pushrod  150  projects from the distal end of the casing  152  and into the aperture  90  of the proximal coupler  80 . An exposed portion  156  of the pushrod  150  between the distal end of the casing  152  and the aperture  90  provides a gripping area for the practitioner to grasp and manipulate the pushrod  150 . Alternatively, the exposed portion  156  can be gripped or engaged by a motorized drive system (not shown) or a non-motorized gear train or other mechanism operated by the practitioner to manipulate the pushrod  150 . Using such a motorized drive system, etc. may advantageously provide for single-handed operation of the apparatus  50  by the practitioner. 
     As shown in  FIGS. 8 and 9 , the pushrod  150  extends through the aperture  90  and into the tubular conduit  84 , where it terminates at a distal tip region  158 , which is shown in an enlarged sectional view of the proximal and distal ends of the pushrod  150  in  FIG. 11  (implant  10  not shown for clarity). As seen in this figure, the distal tip region  158  of the pushrod  150  includes spaced openings  160 ,  162  providing access to an internal lumen  164  that terminates at a distal plug  166 . A wire  168  resides within the lumen  164  except for an implant retaining portion  170  located externally of the lumen  164  between the openings  160 ,  162 . The wire  168  exits and enters the lumen  164  through the openings  160 ,  162  to form the implant retaining portion  170 . The wire  168  can be coupled to the pushrod  150  at or near the distal ends thereof by any suitable means, such as welding, adhesives, crimping of the pushrod  150  onto the wire tip, a friction fit, interference fit, etc. Alternatively, the distal portion of the wire  168  can be located in but not connected to the distal portion of the pushrod  150 . 
     With reference to  FIG. 12 , which illustrates the distal end of the pushrod  150  and the implant  10 , the implant retaining portion  170  attaches the implant  10  to the pushrod  150  for cooperative movement during advancement of the pushrod  150 . In the illustrated embodiment, the implant  10  attaches to the implant retaining portion  170  at the distal end  16  of the body  12  at or near where the tether  14  connects to the body  12 . In particular, the distal end  16  is held between the implant retaining portion  170  of the wire  168  and the portion of the pushrod  150  between the openings  160 ,  162 . In this configuration, the tether  14  and about half of the length of the body  12  are located on one side of the wire  168  and the other half of the length of the body  12  are located on the opposite side of the wire  168 . The body  12  wraps around the wire  168  such that the free ends of the body  12  are folded upon each other form the proximal end  18  of the body  12 , as described above. The implant retaining portion  170  forms a closed noose or snare around the implant  10  that permits the implant  10  to be retained whether the pushrod  150  is pushed distally or pulled proximally. The implant retaining portion  170  can further be configured to hold the implant  10  against the portion of the pushrod  150  between the openings  160 ,  162  tightly enough to prevent shifting of the implant  10 . The above-described attachment of the implant  10  and the pushrod  150  provides an exemplary manner of attachment; the implant  10  and the pushrod  150  can be joined in any suitable manner and are not limited to that described above and shown in the figures. 
     Referring again to  FIG. 11 , the distal end of the wire  168  is removably attached to the distal plug  166  such that the wire  168  separates from the distal plug  166 , or other portion of the pushrod  150 , upon application of a suitable proximal force to the wire  168 . Continuation of the proximal force pulls the wire  168  through the openings  160 ,  162  such that the distal end of the wire  168  resides within the lumen  164  proximally of the openings  160 ,  162 , thereby releasing the implant  10  ( FIG. 12 ) from the wire  168  and the pushrod  150 . Releasing the implant  10  from the pushrod  150  will be described in greater detail with respect to the description below of the operation of the system  46 . The proximal force can be applied by, for example, the practitioner or a motorized drive system, non-motorized gear train or mechanism, etc. pulling on the wire  168 , in which case, a proximal end of the wire  168  can project from the pushrod  150 , such as through the proximal end of the pushrod  150 , as shown in  FIG. 11 . The type and degree of attachment between the wire  168  and the pushrod  150  can be selected according to a desired proximal force required to effect separation of the wire  168  from the pushrod  150 . As examples, the wire  168  can be attached to the pushrod  150  with an adhesive or by chemical joining processes, including various types of welding. Alternatively, the wire  168  can be integrally formed with the pushrod  150  and, optionally, scored, such as by a notch or incision, to facilitate the separation. 
     The pushrod  150  can be manipulated by the practitioner, manually or through the operation of a motorized or non-motorized drive system, between various positions for introducing the implant  10  into a HAS.  FIGS. 8 and 9  illustrate a retracted or storage position of the pushrod  150 ; the storage position corresponds to a position of the pushrod  150  and, thereby, the implant  10  prior to use of the apparatus for introduction of the implant  10  into the HAS (i.e., during storage). In the exemplary storage position of  FIGS. 8 and 9 , the distal tip region  158  of the pushrod  150  resides in the proximal coupler  80 , particularly at the bend between the storage portion  86  and the coupling portion  88  of the tubular conduit  84 , and in axial alignment with the channel  98 . As a result, the implant  10  extends from the pushrod  150 , through the storage portion  86  of the tubular conduit  84 , and through the tube  60  for storage in the storage portion  86  and the tube  60 . 
     The components in which the implant  10  is stored, specifically the storage portion  86  and the tube  60  in the depicted embodiment, can be sized to accommodate the implant  10 . In one embodiment, the storage portion  86  and the tube  60  have a collective length (i.e., the length of the storage portion  86  plus the length of the tube  60  less any overlap between the two components) corresponds to the length of the implant  10 , that is, the distance between the distal and proximal ends  16 ,  18  of the body  12  of the implant  10 . In such an embodiment, the body  12  of the implant  10  extends the collective length of the storage portion  86  and the tube  60  with no or minimal bunching or folding of the body  12 . Alternatively, the collective length of the storage portion  86  and the tube  60  can be less than the length of the body  12  such that the body  12  undergoes some bunching or folding upon itself within the storage portion  86  and/or the tube  60 . In yet another embodiment, the collective length of the storage portion  86  and the tube  60  can be greater than the length of the body  12 . Further, as illustrated in the exemplary embodiment, the storage portion  86  and/or the tube  60  can each have an inner diameter sufficiently large to accommodate the implant  10  in its natural expanded condition. Alternatively, the storage portion  86  and/or the tube  60  can each have an inner diameter that effectively compresses the implant  10  from its expanded condition to a compressed condition, at any appropriate degree of compression. 
       FIGS. 8 and 9  illustrate an exemplary storage position; other storage positions are possible. In other exemplary storage positions, the distal tip region  158  of the pushrod  150  can be located proximally of that shown in  FIGS. 8 and 9 , such as between the aperture  90  and the position shown in  FIGS. 8 and 9 . Alternatively, the distal tip region  158  of the pushrod  150  can be located distally of that shown in  FIGS. 8 and 9 , such as between the position shown in  FIGS. 8 and 9  and the exit opening  100  of proximal coupler  80 . As another alternative, the pushrod  150  can project beyond the exit opening  100  with the implant  10  residing within the proximal coupler  80  and the tube  60 . 
       FIGS. 13 and 14  illustrate an advancing position of the pushrod  150 ; the advancing position corresponds to a position of the pushrod  150  and, thereby, the implant  10  during use of the apparatus for introduction of the implant  10  into the HAS. In the advancing position, the distal tip region  158  of the pushrod  150  is located distally of its location when in the storage position; therefore, any distal movement of the pushrod  150  from the storage position corresponds to moving the pushrod  150  to the advancing position.  FIGS. 13 and 14  illustrate an exemplary advancing position with the implant  10  not shown for clarity. When moving the pushrod  150  from the storage position to the advancing position, the distal tip region  158  of the pushrod  150  advances through the channel  98  and exit opening  100  of the proximal coupler  80  and into the introducer sheath  20 , particularly into the hub proximal opening  34 , through the hub  28 , including the collar  36 , and into the shaft lumen  24  of the introducer sheath  20 , which is held by the distal coupler  82 . As the pushrod  150  so advances, the implant  10  is compressed radially and elongated as it is forced through the tapering introducer guide  94  and into the lumen  24  of the introducer sheath  20 . Thus, when advancing, the pushrod  150  and the implant  10  have a common travel direction leaving the apparatus  50  through the exit opening  100  and entering the introducer sheath  20  through the proximal opening  34 ; in the illustrated embodiment, the travel direction is substantially linear, but other forms of travel direction are possible depending on the configuration of the apparatus  50 . Other positions of the pushrod  150  will be described below in conjunction with the description of methods of use of the system  46 . 
     Embodiments of methods of use of the system  46  are described below. While the system  46  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. The methods can also be modified or adapted as necessary, if necessary, for use with embodiments of the system  46  other than the embodiment employed in the following description. In the description of the methods, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system. 
     In one embodiment of a method of use of the system  46 , various stages of which are depicted in  FIGS. 15-24A , the target HAS (e.g., a vein such as the greater saphenous vein B) can first be accessed at an access site through the skin by using a suitable access technique (e.g., the Seldinger technique). A guidewire is passed into the vein B, and the introducer sheath  20  is fed over the guidewire into the vein B and advanced to the desired implant location. In the case of the greater saphenous vein B, the desired implant location is just below the sapheno-femoral junction H. The guidewire is then withdrawn from the introducer sheath  20 , thereby leaving the shaft  22  or a portion thereof in the vein B. The position of the introducer sheath  20  relative to the vein B and the sapheno-femoral junction H can be verified using appropriate techniques, such as ultrasound imaging.  FIG. 15  illustrates the leg A with the shaft  22  of the introducer sheath  20  located in the greater saphenous vein B and the hub  28  positioned externally of the leg A.  FIG. 15A  provides an enlarged view of the region labeled “XV-A” in  FIG. 15  to show the location of the distal tip portion  26  in the saphenous vein B and relative to the sapheno-femoral junction H. 
     After advancement of the introducer sheath  20  to the desired implant location, the apparatus  50  is coupled to the introducer sheath  20 . To this end, the distal coupler  82  is mounted to the introducer sheath  20 , followed by coupling the proximal and distal couplers  80 ,  82 . In particular, the distal coupler  82  is placed onto the shaft  22  distally of the hub  28 , as indicated by the arrow I in  FIG. 15 , by inserting the shaft  22  through the slot  122  and into the bore  124 , and the distal coupler  82  is then slid proximally along the shaft  22 , as indicated by the arrow J in  FIG. 15 , and onto the hub  28  with the flange  38  and the side port  40  extending through the slot  122 .  FIG. 16  illustrates the introducer sheath  20  with the distal coupler  82  mounted to the hub  28  and the proximal end of the shaft  22 . Alternatively, the distal coupler  82  and the introducer sheath  20  can be coupled together prior to insertion of the introducer sheath  20  into the vein B, whereby the distal coupler  82  can be placed onto the introducer sheath  20  through the slot  122  in the manner described above, or, in another embodiment, the shaft  22  of the introducer sheath  20  can be inserted directly and axially into the bore  124  at the proximal end of the bore  124  rather than radial insertion through the slot  122 . 
     After the distal coupler  82  is mounted to the introducer sheath  20 , the proximal coupler  80  and, thereby, the remainder of the apparatus  50 , is attached to the distal coupler  82 . Particularly, the keys  118  of the distal coupler  82  are inserted into the keyways  104  of the proximal coupler  80 , and the proximal and/or distal couplers  80 ,  82  are manipulated as needed (e.g., rotated or twisted) to construct the bayonet fitting.  FIG. 17  illustrates the introducer sheath  20  with the apparatus  50  mounted thereto. Details of the proximal and distal couplers  80 ,  82  and the introducer sheath  20  in the coupled configuration are described above and shown in  FIGS. 8 and 9 . Notably, the proximal coupler exit opening  100  and the introducer sheath proximal opening  34  are aligned with each other to enable advancement of the pushrod  150  from the apparatus  50 , through both openings  100 ,  34 , and into the introducer sheath  20 , as will be described in more detail below. In the depicted embodiment, the proximal coupler exit opening  100  and the introducer sheath proximal opening  34  are directly adjacent one another to effect the alignment, and other methods of aligning the openings  100 ,  34  are possible. 
     With the apparatus  50  coupled to the introducer sheath  20 , as illustrated in  FIG. 17 , the apparatus  50  can be easily handled and manipulated by the practitioner due to various aspects of the apparatus  50 . One exemplary contributing aspect is the obtuse angle α. Because of the obtuse angle α, the portion of the apparatus  50  located proximally of the angle vertex, i.e., in the depicted embodiment, the storage portion  86  of the proximal coupler  80 , the implant storage unit  52 , and the introducer assembly  56 , hereinafter referred to as the system proximal portion, is angled relative the introducer sheath  20  and the portion of the apparatus  50  located distally of the angle vertex, i.e., in the depicted embodiment, the coupling portion  88  of the proximal coupler  80  and the distal coupler  82 , hereinafter referred to as the system distal portion, when the apparatus  50  is coupled to the introducer sheath  20 . The system proximal portion, depending on the manner in which the practitioner holds the apparatus  50 , can be angled upward, downward, laterally, or a combination of laterally and upward or laterally and downward relative to the system distal portion. As a result, the portion of the apparatus  50  for storing the implant  10 , which defines a storage axis, is offset, particularly, angularly offset, from the location where the implant  10  enters the introducer sheath  20  and the vein B, or the travel direction of the pushrod  150  and the implant  10 . This geometry facilitates ease of use of the apparatus  50  because the practitioner can orient the system proximal portion as desired (i.e., upward, downward, laterally, or combination thereof) to allow the practitioner to comfortably hold the apparatus  50  while locating the gripping area or exposed portion  156  of the pushrod  150  as desired for optimal manual manipulation of the pushrod  150 . 
     When the apparatus  50  is oriented as desired, the practitioner can optionally remove the end cap  64  from the tube  60  such that the implant  10  is no longer anchored at the proximal end of the tube  60 ; the apparatus  50  in this state is ready for introduction of the implant  10  into the vein B. The practitioner grasps the exposed portion  156  of the pushrod  150  and moves the pushrod  150  distally from the storage position (see  FIGS. 8 and 9 ) to and distal of the advancing position (see  FIGS. 13 and 14 ) by applying a proximal force to the pushrod  150 , as illustrated by the arrow K in  FIG. 17 , thereby advancing the pushrod  150  and the implant  10  through the coupler assembly  54 . In particular, as depicted in  FIGS. 13 and 14 , the pushrod  150  and the implant  10  (not shown for clarity) move distally through the channel  98  and the exit orifice  100  of the proximal coupler  80  to enter the introducer sheath  20  at the proximal opening  34 . The introducer guide  94  directs the pushrod  150  toward the channel  98  if the pushrod  150  diverges from axial alignment with the channel  98  prior to entering the channel  98 . After entering the proximal opening  34 , the pushrod  150  and the implant  10  continue their advancement through the hub  28  and into the lumen  24  of the shaft  22 . 
     As the pushrod  150  advances the implant  10  through the proximal coupler  80 , the body  12  of the implant  10  converts from its expanded condition to a compressed condition as a result of the relatively small cross-sectional diameter of the channel  98  and exit opening  100 ; the channel  98  effectively forces the implant body  12  to compress in order to pass therethrough. The introducer guide  94  also facilitates the compression of the implant body  12  as it approaches the channel  98  by gradually reducing the cross-sectional diameter of the implant body  12 . Lengthening of the implant body  12  can accompany the compression. Because the proximal opening  34 , the hub  28 , and the shaft lumen  24  of the introducer sheath  20  preferably have a cross-sectional diameter about equal to that of the channel  98  and the exit opening  100 , the implant body  12  retains substantially the same compressed condition as it moves through the introducer sheath  20 . 
     The pushrod  150  and the implant  10  cease advancement when reaching the desired implant location, which is just below the sapheno-femoral junction H in the present example.  FIG. 18  illustrates the pushrod  150  and the implant  10  fully advanced into the greater saphenous vein B to just below the sapheno-femoral junction H. In one embodiment, the practitioner advances the pushrod  150  and the implant  10  until the distal end of the pushrod  150  is aligned with the distal tip portion  26  of the shaft  22  as observed under imaging guidance, such as ultrasound guidance. Depending on the resolution of the imaging equipment and other factors, the distal end of the pushrod  150  can be flush with the distal tip portion  26  of the shaft  22  (i.e., the pushrod end does not project beyond the shaft  22 ), or the distal end of the pushrod  150  can project beyond the shaft distal tip portion  26  when observed as being aligned. In another embodiment, the practitioner can advance the distal end of the pushrod  150  beyond the distal tip portion  26  of the shaft  22 . With the pushrod  150  and the implant  10  fully advanced, the implant  10 , including the tether  14 , preferably extends along the entire length of the shaft lumen  24 . 
     While the method of use of the system  46  is described in terms of advancement of the pushrod  150  and implant  10  to place the implant  10  at the desired implant location, some proximal retraction of the may also accompany the placement of the implant  10 . Since the implant retaining portion  170  of the pushrod  150  forms a closed noose or snare around the implant  10 , the pushrod  150  can be retracted proximally to withdraw the implant  10 , which is a useful feature in case the pushrod  150  and implant  10  are advanced beyond the desired implant location. This feature can further be used to add additional bulk to the implant  10  once it is placed at the desired implant location, as described below. 
     After the pushrod  150  and the implant  10  are advanced to the desired implant location, the practitioner disconnects the proximal coupler  80  from the distal coupler  82  and pulls the implant storage unit  52  and the proximal coupler  80  proximally away from the introducer sheath  20  a predetermined distance, as illustrated in  FIG. 19 . During the decoupling of the coupler assembly  54  and retraction of the implant storage unit  52 , the pushrod  150  and the implant  10  remain in the position shown in  FIG. 18  in the vein B; thus, the pushrod casing  152  moves proximally along the pushrod  150 , thereby exposing a greater length of the pushrod  150 . The predetermined distance between the introducer sheath  20  and the implant storage unit  52  can be selected to expose a predetermined length of the implant  10  between the introducer sheath  20  and the implant storage unit  52 . In one embodiment, the practitioner pulls the implant storage unit  52  and the proximal coupler  80  to expose about 4 cm of the implant  10 . The practitioner then trims the implant body  12  and the tether  14  at the exposed portion. After trimming the implant  10 , the practitioner continues to pull the implant storage unit  52 , the proximal coupler  80  and, thus, the pushrod casing  152 , proximally away from the introducer sheath  20  to fully uncoil and expose the pushrod  150  and separate the pushrod  150  and the implant  10  from the remainder of the apparatus  50 .  FIG. 20  illustrates the introducer sheath  20 , the pushrod  150 , and the implant  10  in the leg A after removal of the implant storage unit  52 . 
     Removal of the introducer sheath  20  follows removal of the implant storage unit  52 . In one embodiment, the practitioner removes the introducer sheath  20  by holding the pushrod  150  fixed to maintain the implant  10  just below the sapheno-femoral junction H and withdrawing the introducer sheath  20  completely from the vein B. As the introducer sheath  20  is withdrawn from the vein B, the implant body  12  expands from the compressed condition when in the introducer sheath shaft  22  to effectively fill the vein B less the space occupied by the pushrod  150 .  FIG. 21  illustrates the pushrod  150  and the implant  10  in the greater saphenous vein B after removal of the introducer sheath  20 . 
     With the pushrod  150  and the implant  10  in the vein B, the practitioner releases the implant  10  from the pushrod  150 . In one embodiment, the practitioner can withdraw the pushrod  150  a predetermined distance prior to releasing the implant  10 . As an example, the practitioner can withdraw the pushrod  150  about 1 cm below the sapheno-femoral junction H to position the distal end  16  of the implant  10  about 2.5 cm below the sapheno-femoral junction H as the distal end  16  of the implant  10  in the illustrated embodiment is located about 1.5 cm proximally of the distal end of the pushrod  150 . Withdrawal of the pushrod  150  after placement in the vein B but prior to releasing the implant  10  can reduce longitudinal tension in the body  12  of the implant and allow the body  12  near the distal end  16  the freedom and space to bulk up or expand even further from the expanded condition following removal of the introducer sheath  20 . 
     The practitioner then applies a proximal force to the wire  168 , such as by pulling on the proximal end of the wire  168 , thereby detaching the wire  168  from the distal plug  166 . Continued application of the proximal force retracts the wire  168  through the openings  160 ,  162  and releases the implant  10  from between the wire  168  and the pushrod  150 , as illustrated in  FIG. 22 . The wire  168  can be retracted any desired distance corresponding to releasing the implant  10  from the pushrod  150 . For example, the wire  168  need not be retracted through the proximally located opening  160  if pulling the wire  168  through only the distally located opening  162  effects release of the implant  10 . The retraction of the wire  168  through the proximally located opening  160  removes the implant retaining portion  170  from the implant  10  and gives the pushrod  150  a lower profile since the wire  168  is contained within the circumferential profile of the pushrod  150 . 
     The practitioner follows release of the implant  10  with retraction of the pushrod  150  from the vein B. The removal of the implant retaining portion  170  when releasing the implant  10  and the lower profile during pushrod removal reduce the possibility of snagging the implant  10  on the pushrod  150  as the pushrod  150  is retracted from the vein B. If desired, the practitioner can apply external compression to the vein B and the implant  10  to maintain the position of the implant  10  in the vein B. The distal end  16  of the implant  10  retains its position in the vein B during retraction of the pushrod  150  due to its apposition against the vein wall, which is aided with coagulation or “sticking” by blood that is present in the vicinity.  FIG. 23  illustrates the implant  10  in the greater saphenous vein B after removal of the pushrod  150 . 
     The practitioner can optionally secure the implant  10  to the leg A following removal of the pushrod  150 . In one embodiment, the implant body  12  can be trimmed the location where the implant body  12  exits the leg A (i.e., the access site), and the tether  14  can be trimmed a desired length beyond the location where the tether  14  exits the leg A to form a tether securing portion  180  projecting from the leg A. The securing portion  180  can be taped or otherwise attached to the exterior surface, i.e., the skin, of the leg A, as shown in  FIG. 24  and in greater detail in  FIG. 24A , which is an enlarged view of the exterior surface of the leg A, particularly the region of the leg A labeled “XXIV-A” in  FIG. 24 . With the distal end of the tether  14  attached to the distal end  16  of the implant body  12 , and with the securing portion  180  attached to the skin, the tether  14  prevents migration of the implant  10  in the direction of the sapheno-femoral junction. In another embodiment, the implant  10 , including the tether  14 , can be secured to the access site by incorporation with access site sutures, such as 4-0 Vicryl braided or similar sutures. 
     During the storage and introduction of the implant  10 , the implant body  12  assumes multiple conditions with respect to the expansion and compression of the implant body  12 .  FIGS. 25A-25C  illustrate sectional views of the implant body  12  in the exemplary conditions. As examples, the implant body  12  in the illustrated embodiment assumes an expanded condition when in the implant storage unit  52  of the apparatus  50  during storage (i.e., a storage condition,  FIG. 25A ), a first compressed condition when in the shaft  22  of the introducer sheath  20  during introduction (i.e., an introduction condition,  FIG. 25B ), and, assuming the HAS has a differing cross-sectional diameter than the shaft  22 , a second compressed condition when in the HAS, shown as the greater saphenous vein B for illustrative purposes, after implantation (i.e., an implantation condition,  FIG. 25C ). The implant body  12  also undergoes transitional conditions when converting between the storage, introduction, and implantation conditions. These conditions are imposed on the implant body  12  because of the cross-sectional diameter of the structure that houses the implant body  12 ; once the housing structure cross-sectional diameter is sufficient to cause compression of the implant body  12 , compression of the implant body  12  increases as the housing structure cross-sectional diameter decreases. The housing structures corresponding to the storage, introduction, and implantation conditions of the illustrated embodiment are, respectively, the tube  60  of the implant storage unit  52 , the shaft  22  of the introducer sheath  20 , and the HAS, in this case, the greater saphenous vein B. 
     The order of the steps described above for the method of use of the system  46  can be performed in any desired and suitable order and are not intended to be limited to the order the steps are described above. For example, the retraction of the pushrod  150  and the introducer sheath  20  can occur in any desired order, i.e., the pushrod  150  first, the introducer sheath  20  first, or the pushrod  150  and introducer sheath  20  simultaneously. 
     The method can be used with the illustrated apparatus  50 , other embodiments of the illustrated apparatus  50 , or other types of apparatuses for storage and/or introduction of the implant  10  or other suitable implant. Similarly, the apparatus  50  can be employed with the illustrated implant  10 , other embodiments of the illustrated implant  10 , or other types of occluding implants. The case is the same with respect to the use of the introducer sheath  20  with the apparatus  50 . 
     The apparatus  50  can be provided as a ready-to-use kit having the implant  10  disposed in the implant storage unit  52  and connected to the pushrod  150  such that the apparatus  50  can be removed from its packaging for immediate surgical use. In one embodiment, the kit includes only the apparatus  50 ; alternatively, the kit can optionally include the introducer sheath  20  such that the entire system  46  is provided as a ready-to-use kit. In one embodiment, the apparatus  50  can be a single use device that is disposed after surgical use. Alternatively, the apparatus  50  can be a multiple use device that can be sterilized and provided with a new implant  10  and, if necessary, a new pushrod  150  having a new wire  168 , for each surgical use. 
       FIG. 26  illustrates another embodiment of an apparatus  200  configured for storing and/or surgically introducing the implant  10  into a HAS, which apparatus  200  can be included in a system  190  with the implant  10  of  FIG. 2 , or other suitable implant, and the introducer sheath  20  of  FIG. 3 , or other suitable introducer sheath. The apparatus  200  can be similar in structure, function and method of use to the apparatus  50  of  FIGS. 4-25C , except as further described herein. The depicted apparatus  200  comprises a coupler assembly  202  configured to couple the apparatus  200  to an introducer sheath, such as the introducer sheath  20  of  FIG. 3 , and a combined implant storage/introducer unit  204  adapted to store the implant  10  prior to and during introduction of the implant  10  into the HAS. The storage/introducer unit  204  is adapted to feed the implant through the coupler assembly  202 , and into the introducer sheath  20  for placement of the implant  10  in the HAS, when manipulated by the practitioner. 
     With additional reference to  FIG. 27 , where the apparatus  200  is illustrated as exploded, the implant storage/introducer unit  204  of the depicted embodiment comprises a single casing  206  sized to accommodate both the implant  10  and an introducer assembly  208 , as will be disclosed in further detail below. The casing  206  comprises a right housing shell and  210  a left housing shell  212  adapted for cooperative registry. 
     Referring to  FIG. 28 , the right housing shell  210  comprises a curved side wall  214  joined to an inner wall  216  and an outer wall  218 . The walls  214 ,  216 ,  218  are contoured, and can be configured with openings, bosses, flanges, and the like, for operational support of the elements comprising the apparatus  200 . The right housing shell  210  can be molded such that the openings, bosses, flanges, and the like are integrally formed with the right housing shell  210 . As illustrated, the continuity of the outer wall  218  is interrupted by a first opening  220  and a second opening  222 . The right housing shell  210  further has multiple hollow bosses  224  spaced along the inner and outer walls  216 ,  218 . 
     A first, inner flange  226  extends from the side wall  214  in spaced relation to the inner wall  216  and forms a closed loop. A second, middle flange  228  extends mainly from the side wall  214  in spaced relation to the inner flange  226 . The middle flange  228  has a first end  230  and a second end  232  that do not meet each other; rather, the middle flange  228  is formed as a spiral, with the first end  230  being disposed on the side wall  214  and inwardly spaced from the outer wall  218 , and the middle flange  228  gradually spirals outwardly until the second end  232  joins the outer wall  218 . A third, outer flange  234  extends mainly from the side wall  214  and has a first end  239  which meets the outer wall  218  adjacent the first opening  220  and a second end  236  which joins with the first end  230  of the middle flange  228 . The flanges  226 ,  228 ,  234  cooperatively form a channel  240  in communication with the first opening  220 , with the channel  240  following a generally spiral-shaped path defined by the flanges  226 ,  228 ,  234 . The channel  240  at least partially receives and/or stores the introducer assembly  208 , as will be described below. 
     The left housing shell  212 , shown in  FIG. 29 , is generally a mirror image of the right housing shell  210 , and includes some, but not all, of the same structural elements of the right housing shell  210 . Particularly, as illustrated, the left housing shell  212  preferably does not include any flanges or hollow bosses, but does include a curved side wall  242  joined to an inner wall  244  and an outer wall  246  with first and second openings  248 ,  250 , respectively, in mirrored-relation to those corresponding features of the right housing shell  210 . The walls define a cavity  252  in which the implant  10  is at least partially stored, as will be described below. The left housing shell  212  further has multiple projections  254  spaced along the inner and outer walls  244 ,  248  for receipt within the hollow bosses  224  on the right housing shell  210 . The left housing shell  212  can be molded such that the openings, projections, and the like are integrally formed with the left housing shell  212 . 
     Referring to  FIG. 30 , when the right and left housing shells  210 ,  212  are assembled, the hollow bosses  224  ( FIG. 28 ) receive the projections  254  ( FIG. 29 ) and the inner walls  216 ,  244  and the outer walls  218 ,  246  meet in cooperative registry to form the casing  206 . The first openings  220 ,  248  register to form a single first aperture  256  and the second openings  222 ,  250  register to form a single second aperture  258 ; thus, in total, the assembled casing  206  can form two apertures. 
     The assembled casing  206  has a closed-loop portion  260  that that is generally oval in shape except for a saddle-like portion  262  and a coupler portion  264  extending generally from one of the junctures between the closed-loop portion  260  and the saddle-like portion  262 . The first aperture  256  is formed at or near one end of the saddle-like portion  262  and the second aperture  258  is formed at the coupler portion  264  (which can be at or near the opposite end of the saddle-like portion  262 ). The second aperture  258  can be generally collinear with the longitudinal axis of the coupler portion  264 . The channel  240  ( FIG. 28 ) that at least partially receives and/or stores the introducer assembly  208  and the cavity  252  ( FIG. 29 ) in which the implant  10  is at least partially stored are both generally formed along and situated within the closed-loop portion  260  and the saddle-like portion  262 . 
     The casing  206  can be shaped to facilitate comfortable gripping of the implant storage/introducer unit  204 . The implant storage/introducer unit  204  can be gripped according to the practitioner&#39;s preference, such as with one hand wrapped around the saddle-like portion  262  or part of the closed-loop portion  260 , although other gripping arrangements or techniques are possible. 
     Referring now to  FIGS. 31 and 32 , which are enlarged views of the region labeled “XXXI” in  FIG. 26 , the depicted coupler assembly  202  that couples the apparatus  200  to the introducer sheath  20  is shown. The coupler assembly  202  can comprise a distal coupler that can be similar or identical to the distal coupler  82  shown in  FIGS. 7-10 , and will therefore not be further described for this embodiment, and like elements of the distal coupler  82  will be referred to with the same reference numerals. The coupler assembly  202  further comprises a proximal coupler which mates with the distal coupler  82 . In the depicted embodiment, the proximal coupler is integrally formed as part of the casing  206  as the coupler portion  264 , and therefore may alternately be considered part of the implant storage/introducer unit  204  rather than the coupler assembly  202 . The coupler portion or proximal coupler  264  includes a tubular conduit having a storage portion  266  and a coupling portion  268 . As best viewed in the perspective view of  FIG. 32 , the storage portion  266  joins the saddle-like portion  262  of the casing  206  to thereby connect the cavity  252  in which the implant  10  is at least partially stored, and the storage portion  266  of the proximal coupler  264 . The casing  206  and the proximal coupler  264  do not have to be integrally molded, and can be joined in any suitable fashion, such as, for example, an interference fit, with an adhesive, a snap fit, etc. The second aperture  258  is formed through a side wall of the storage portion  266 , and is aligned and can be generally collinear with the longitudinal axis of the coupling portion  268  and the exit opening  100 , and, when the system  190  is assembled, the proximal opening  30  of the hub  28  and the lumen  24  of the introducer sheath shaft  22 . 
     As shown in  FIGS. 31 and 32 , the coupling portion  268  houses an insert that can be similar or identical to the insert  92  shown in  FIGS. 8-9 , and will therefore not be further described for this embodiment, and like elements of the insert  92  will be referred to with the same reference numerals. In this embodiment, the channel  98  and the exit opening  100  of the insert  92  are oriented in axial alignment with the second aperture  258 . The insert  92  can be secured to the coupling portion  268  in any suitable fashion, such as, for example, an interference fit, with an adhesive, a snap fit, etc.; alternatively, the insert  92  or the features of the insert  92  can be integrally formed with the coupling portion  268 . The insert  92  will in turn receive the distal coupler  82  as described for the apparatus  50  of  FIGS. 4-14 . 
     While the proximal coupler  264  has been described as comprising the storage portion  266  and the coupling portion  268  that houses the insert  92 , the proximal coupler  264  can alternatively be considered as comprising only the insert  92 , which performs a coupling function, with the casing  206 , which performs a storage function, considered as an extension or part of the implant storage/introducer unit  204 . Regardless, the exit opening  100  functions as an exit opening for the implant storage/introducer unit  204  and the overall apparatus  200  as the implant  10  exits the implant storage/introducer unit  204  and the apparatus  200  through the exit opening  100 . The proximal coupler  264  and the insert  92  can be constructed in any desired manner with either or both parts functioning to partially store the implant  10  and/or couple the apparatus  200  to the introducer sheath  20 . 
     The proximal and distal couplers  264 ,  82  of the coupler assembly  202  can be connected together, as shown in  FIGS. 31 and 32 , to couple the apparatus  200  to the introducer sheath  20 . In the coupled condition, the proximal and distal couplers  264 ,  82  retain the hub  28  of the introducer sheath  20  therebetween, as described above with respect to  FIGS. 8-9 . In the current embodiment, due to the placement of the hub  28  relative to the proximal and distal couplers  264 ,  82 , the second aperture  258  and the channel  98  align axially with the proximal opening  34  of the hub  28  and, thereby, the lumen  24  at the proximal end of the shaft  22 . 
     Referring back to  FIG. 27 , the depicted embodiment of the implant storage/introducer unit  204  of the apparatus  200  comprises the introducer assembly  208  partially stored within the casing  206  along with the implant  10 . The introducer assembly  208  includes an introducer or pushrod that can be similar or identical to the pushrod  150  shown in  FIGS. 8-9 , and will therefore not be further described for this embodiment, and like elements of the insert  150  will be referred to with the same reference numerals. In this embodiment, the introducer assembly  208  further comprises a tubular housing  270  defining a lumen  272  in which the pushrod  150  is partially stored. The length of the housing  270  is sufficient to encase the proximal end of the pushrod  150  prior to use of the apparatus  200  for delivery of the implant  10 . Further, the housing  270  can be coiled one or more times within the casing  206  to accommodate the length of the pushrod  150  and, thereby, maintain a relatively compact configuration for the apparatus  200 . 
     As shown in  FIGS. 33-36 , the implant  10  and the introducer assembly  208  are commonly stored by the casing  206 . As shown in  FIG. 33  in particular, in which the implant  10  is not shown for clarity, the introducer assembly  208  is received in and retained by the right housing shell  210  by placing the housing  270  in the channel  240  created by the flanges  226 ,  228 ,  234 , with the distal end of the pushrod  150  extending out of the first aperture  256  and into the second aperture  258 . The pushrod  150  projects from the distal end of the housing  270 , through the first and second apertures  256 ,  258 , and into the proximal coupler  264 , where it terminates at a distal tip region, which can be similar or identical to the distal tip region  158  shown in  FIG. 11 , and will therefore not be further described for this embodiment, and like elements of the distal tip region  158  will be referred to with the same reference numerals. 
     The exposed portion  156  of the pushrod  150  between the two apertures  256 ,  258  provides a gripping area for the practitioner to grasp, either manually or through the operation of a motorized drive system, or a non-motorized drive system, gear train, or other mechanism that engages the pushrod  150 , and manipulate the pushrod  150 , and can generally follow the natural curve created by the closed-loop portion  260  of the casing  206 . The exposed portion  156  generally extends over the saddle-like portion  262  of the casing  206 , and the offset between the pushrod  150  and the saddle-like portion  262  allows the practitioner to grip and apply force to (e.g., push distally or pull proximally) the pushrod  150  at a location close to its distal tip region  158 . 
     As best viewed in the sectional views of  FIGS. 35 and 36 , the housing  270  can be coiled one or more times to extend along the channel  240 . The flanges  226 ,  228 ,  234  function as guides and help maintain the housing  270  in an orderly coil within the casing  206 . 
     As shown in  FIG. 34  in particular, in which a portion of the pushrod  150  is shown for clarity, the implant  10  is received in the cavity  252  of the left housing shell  212 . The implant  10  attaches to the distal tip region  158  in a manner similar to that described above with reference to  FIGS. 11 and 12 , and will therefore not be further described for this embodiment. The implant  10  generally extends back from its point of attachment to the distal tip region  158  of the pushrod  150 , through the storage portion  266  of the proximal coupler  264 , and through the cavity  252  for storage in the storage portion  266  and the casing  206 , as can further be seen in  FIG. 34 . As a result, the implant  10  extends from the pushrod  150 , which is positioned in the proximal coupler  264 , along the saddle-like portion  262 , and around the closed-loop portion  260  of the casing  206 . 
     The components in which the implant  10  is stored, specifically the storage portion  266 , the saddle-like portion  262 , and the closed-loop portion  260  (the portions  266 ,  262 ,  260 ) of the casing  206  in the depicted embodiment, can be sized to accommodate the implant  10 . In one embodiment, the portions  266 ,  262 ,  260  have a collective effective length (i.e., the length of the storage portion  266  plus the length of the saddle-like portion  262  plus the length of the closed-loop portion  260 , less any overlap between the components) corresponds to the length of the implant  10 , that is, the distance between the distal and proximal ends  16 ,  18  of the body  12  of the implant  10 . In such an embodiment, the body  12  of the implant  10  extends the collective effective length of the portions  266 ,  262 ,  260  with no or minimal bunching or folding of the body  12 . Alternatively, the collective length of the portions  266 ,  262 ,  260  can be less than the length of the body  12  such that the body  12  undergoes some bunching or folding upon itself within the portions  266 ,  262 ,  260 . In yet another embodiment, the collective length of the portions  266 ,  262 ,  260  can be greater than the length of the body  12 . 
     Further, as illustrated in the exemplary embodiment, the storage portion  266  and the cavity  252  can be sized sufficiently large to accommodate the implant  10  in its natural or default expanded condition. Alternatively, the storage portion  266  and the cavity  252  can each have a size that effectively compresses the implant  10  from its expanded condition to a compressed condition, at any appropriate degree of compression. As best viewed in the sectional views of  FIGS. 35 and 36 , the ends of the flanges  226 ,  228 ,  234  may help retain the implant  10  within the cavity  252 . 
     The pushrod  150  can be manipulated by the practitioner between various positions for introducing the implant  10  into a HAS.  FIGS. 31 and 32  illustrate a retracted or storage position of the pushrod  150 ; the storage position corresponds to a position of the pushrod  150  and, thereby, the implant  10  prior to use of the apparatus  200  for introduction of the implant  10  into the HAS (i.e., during storage). In the exemplary storage position of  FIGS. 31 and 32 , the distal tip region  158  of the pushrod  150  resides in the proximal coupler  264 , particularly at the bend between the storage portion  266  and the coupling portion  268  of the tubular conduit, and in axial alignment with the channel  98 . 
       FIGS. 31 and 32  illustrate an exemplary storage position; other storage positions are possible. In other exemplary storage positions, the distal tip region  158  of the pushrod  150  can be located proximally of that shown in  FIGS. 31 and 32 , such as between the second aperture  258  and the position shown in  FIGS. 31 and 32 . Alternatively, the distal tip region  158  of the pushrod  150  can be located distally of that shown in  FIGS. 31 and 32 , such as between the position shown in  FIGS. 31 and 32  and the exit opening  100  of the proximal coupler  64 . As another alternative, the pushrod  150  can project beyond the exit opening  100  with the implant  10  residing within the casing  206 . 
       FIGS. 37 and 38  illustrate an advancing position of the pushrod  150 ; the advancing position corresponds to a position of the pushrod  150  and, thereby, the implant  10  during use of the apparatus  200  for introduction of the implant  10  into the HAS. In the advancing position, the distal tip region  158  of the pushrod  150  is located distally of its location when in the storage position; therefore, any distal movement of the pushrod  150  from the storage position tends to move the pushrod  150  to (or towards) the advancing position.  FIGS. 37 and 38  illustrate an exemplary advancing position with the implant  10  not shown for clarity. When moving the pushrod  150  from the storage position to the advancing position, the distal tip region  158  of the pushrod  150  advances through the channel  98  and exit opening  100  of the proximal coupler  264  and into the introducer sheath  20 , particularly into the hub proximal opening  34 , through the hub  28 , including the collar  36 , and into the shaft lumen  24  of the introducer sheath  20 , which is held by the distal coupler  82 . As the pushrod  150  so advances, the implant  10  is compressed radially and elongated as it is forced through the tapering introducer guide  94  and into the lumen  24  of the introducer sheath  20 . Thus, when advancing, the pushrod  150  and the implant  10  have a common travel direction leaving the apparatus  200  through the exit opening  100  and entering the introducer sheath  20  through the proximal opening  34 . In the illustrated embodiment, the travel direction is substantially linear, but other forms of travel direction are possible depending on the configuration of the apparatus  200 . Other positions of the pushrod  150  will be described below in conjunction with the description of methods of use of the system  190 . 
     Embodiments of methods of use of the system  190  are described below. While the system  190  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. The methods can also be modified or adapted, as necessary, for use with embodiments of the system  190  other than the embodiment employed in the following description. Aspects of the method of use of the system  190  that overlap with the method of use of the system  46 , described above, will be briefly summarized, but will not be described in detail. In the description of the methods, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system, gear train, mechanism, etc. 
     In one embodiment of a method of use of the system  190 , various stages of which are depicted in  FIGS. 39-41 , the target HAS (e.g., a vein such as the greater saphenous vein B) can first be accessed at an access site through the skin and the introducer sheath  20  is advanced to the desired implant location as described above for the system  46  with respect to  FIGS. 15 and 15A . After advancement of the introducer sheath  20  to the desired implant location, the apparatus  200  is coupled to the introducer sheath  20  by first placing the distal coupler  82  onto the shaft  22  and thereafter attaching the proximal coupler  264  and, thereby, the remainder of the apparatus  200 , to the distal coupler  82 , as described above for  FIGS. 15 and 16 . 
       FIG. 39  illustrates the introducer sheath  20  with the apparatus  200  coupled thereto. Details of the proximal and distal couplers  264 ,  82  and the introducer sheath  20  in the coupled configuration are described above and shown in  FIGS. 31 and 32 . Notably, the proximal coupler exit opening  100  and the introducer sheath proximal opening  34  are aligned with each other to enable advancement of the pushrod  150  from the apparatus  200 , through both openings  100 ,  34 , and into the introducer sheath  20 , as will be described in more detail below. In the depicted embodiment, the proximal coupler exit opening  100  and the introducer sheath proximal opening  34  are directly adjacent one another to effect the alignment, although other methods of aligning the openings  100 ,  34  are possible. 
     With the apparatus  200  coupled to the introducer sheath  20 , as illustrated in  FIG. 39 , the apparatus  200  can be easily handled and manipulated by the practitioner due to various aspects of the apparatus  200 . One exemplary contributing aspect is the casing  206  that stores both the implant  10  and the introducer assembly  208 . Because the implant  10  and the introducer assembly  208  are commonly stored within a single casing, the apparatus  200  can be made more compact and may be easier the handle. Furthermore, because the casing  206  is shaped as a closed loop, and the implant  10  and introducer assembly  208  are at least partially stored within the closed loop, the apparatus can be made even more compact in comparison to the embodiment of the apparatus  50  above that stores the implant in a straight tube  60 . Another exemplary contributing aspect is the saddle-like portion  262  of the casing  206 . The offset between the exposed portion  156  of the pushrod  150  and the saddle-like portion  262  allows the practitioner to grip the pushrod  150  closer to its distal tip region  158  where the pushrod is coupled to the implant  10 . 
     The apparatus  200  in this state is ready for introduction of the implant  10  into the vein B. The practitioner grasps the exposed portion  156  of the pushrod  150  and moves the pushrod  150  distally from the storage position (see  FIGS. 31 and 32 ) to and distal of the advancing position (see  FIGS. 37 and 38 ) by applying a proximal force to the pushrod, as illustrated by the arrow L in  FIG. 37 , thereby advancing the pushrod  150  and the implant  10  through the coupler assembly  202 . In particular, as depicted in  FIGS. 37 and 38 , the pushrod  150  and the implant  10  (not shown for clarity) move distally through the channel  98  and the exit orifice  100  of the proximal coupler  264  to enter the introducer sheath  20  at the proximal opening  34 . The introducer guide  94  directs the pushrod  150  toward the channel  98  if the pushrod  150  diverges from axial alignment with the channel  98  prior to entering the channel  98 . After entering the proximal opening  34 , the pushrod  150  and the implant  10  continue their advancement through the hub  28  and into the lumen  24  of the shaft  22 . 
     As the pushrod  150  advances the implant  10  through the proximal coupler  264 , the body  12  of the implant  10  changes conditions from its expanded condition to a compressed condition as a result of the relatively small cross-sectional diameter of the channel  98  and exit opening  100 ; the channel  98  effectively forces the implant body  12  to compress in order to pass therethrough. The introducer guide  94  also facilitates the compression of the implant body  12  as it approaches the channel  98  by gradually reducing the cross-sectional diameter of the implant body  12 . Lengthening of the implant body  12  can accompany the compression. Because the proximal opening  34 , the hub  28 , and the shaft lumen  24  of the introducer sheath  20  preferably have a cross-sectional diameter about equal to that of the channel  98  and the exit opening  100 , the implant body  12  retains substantially in the same compressed condition as it moves through the introducer sheath  20 . 
     The pushrod  150  and the implant  10  cease advancement when reaching the desired implant location, which is just below the sapheno-femoral junction H, as illustrated in  FIG. 18 . After the pushrod  150  and the implant  10  are advanced to the desired implant location, the practitioner disconnects the proximal coupler  264  from the distal coupler  82  and pulls the implant storage/introducer unit  204  and the proximal coupler  264  proximally away from the introducer sheath  20  by a suitable distance, as illustrated in  FIG. 40 . During the decoupling of the coupler assembly  202  and retraction of the implant storage/introducer unit  204 , the pushrod  150  and the implant  10  remain in the position shown in  FIG. 18  in the vein B; thus, the housing  270  moves proximally along the pushrod  150 , thereby exposing a greater length of the pushrod  150 . The distance between the introducer sheath  20  and the implant storage/introducer unit  204  shown in  FIG. 40  can be selected to expose a predetermined length of the implant  10  between the introducer sheath  20  and the implant storage/introducer unit  204 . In one embodiment, the practitioner pulls the implant storage/introducer unit  204  and the proximal coupler to expose about 10-50 cm of the implant  10 . The practitioner then trims the implant body  12  and the tether  14  at the exposed portion. After trimming the implant  10 , the practitioner continues to pull the implant storage/introducer unit  204  and the proximal coupler  264  proximally away from the introducer sheath  20  to fully uncoil and expose the pushrod  150  and separate the pushrod  150  and the implant  10  from the remainder of the apparatus  200 .  FIG. 41  illustrates the introducer sheath  20 , the pushrod  150 , and the implant  10  in the leg A after removal of the implant storage/introducer unit  204 . 
     The remaining steps in the method of use of the system  190  are similar to the final steps of the method of use of the system  46 . Removal of the introducer sheath  20  follows removal of the implant storage/introducer unit  204 , described for and illustrated in  FIG. 21  which illustrates the pushrod  150  and the implant  10  in the greater saphenous vein B after removal of the introducer sheath  20 . With the pushrod  150  and the implant  10  in the vein B, the practitioner releases the implant  10  from the pushrod  150 , as described for and illustrated in  FIG. 22 , which illustrates the implant  10  released from between the wire  168  and the pushrod  150 . The practitioner follows release of the implant  10  with retraction of the pushrod  150  from the vein B, as described for and illustrated in  FIG. 23  which illustrates the implant  10  in the greater saphenous vein B after removal of the pushrod  150 . The practitioner can optionally secure the implant  10  to the leg A following removal of the pushrod  150  described for and illustrated in  FIGS. 24 and 24A . 
     During the storage and introduction of the implant  10 , the implant body  12  assumes multiple conditions with respect to the expansion and compression of the implant body  12 . The implant body  12  in the illustrated embodiment assumes an expanded condition when in the implant storage/introducer unit  204  of the apparatus  200  during storage (i.e., a storage condition), as best seen in  FIGS. 35 and 36 . A first compressed condition when in the shaft  22  of the introducer sheath  20  during introduction (i.e., an introduction condition) is shown in  FIG. 25B , and, assuming the HAS has a differing cross-sectional diameter than the shaft  22 , a second compressed condition when in the HAS, shown as the greater saphenous vein B for illustrative purposes, after implantation (i.e., an implantation condition), as shown in  FIG. 25C . The implant body  12  also undergoes transitional conditions when converting between the storage, introduction, and implantation conditions. These conditions are imposed on the implant body  12  because of the cross-sectional diameter of the structure that houses the implant body  12 ; once the housing structure cross-sectional diameter is sufficient to cause compression of the implant body  12 , compression of the implant body  12  increases as the housing structure cross-sectional diameter decreases. The housing structures corresponding to the storage, introduction, and implantation conditions of the illustrated embodiment are, respectively, the cavity  252  of the implant storage/introducer unit  204 , the shaft  22  of the introducer sheath  20 , and the HAS, in this case, the greater saphenous vein B. 
     The order of the steps described above for the method of use of the system  190  can be performed in any desired and suitable order and are not intended to be limited to the order the steps are described above. For example, the retraction of the pushrod  150  and the introducer sheath  20  can occur in any desired order, i.e., the pushrod  150  first, the introducer sheath  20  first, or the pushrod  150  and introducer sheath  20  simultaneously. 
     The method can be used with the illustrated apparatus  200 , other embodiments of the illustrated apparatus  200 , or other types of apparatuses for storage and/or introduction of the implant  10  or other suitable implant. Similarly, the apparatus  200  can be employed with the illustrated implant  10 , other embodiments of the illustrated implant  10 , or other types of occluding implants. The case is the same with respect to the use of the introducer sheath  20  with the apparatus  200 . 
     The apparatus  200  can be provided as a ready-to-use kit having the implant  10  disposed in the implant storage/introducer unit  204  and connected to the pushrod  150  such that the apparatus  200  can be removed from its packaging for immediate surgical use. In one embodiment, the kit includes only the apparatus  200 ; alternatively, the kit can optionally include the introducer sheath  20  such that the entire system  190  is provided as a ready-to-use kit. In one embodiment, the apparatus  200  can be a single use device that is disposed after surgical use. Alternatively, the apparatus  200  can be a multiple use device that can be sterilized and provided with a new implant  10  and, if necessary, a new pushrod  150  having a new wire  168 , for each surgical use. 
     One problem that has been observed with some occluding implants, such as implant  10  of  FIG. 2 , is blood leakage around or through the implant near the sapheno-femoral junction H (see  FIG. 1 ). This may be a result of the blood flow at the sapheno-femoral junction H pushing the implant to one side of the vein and allowing blood to flow past the implant, and/or from insufficient bulk or packing density of the implant, which can allow blood to flow between the fibers of the implant itself. Blood leakage may be prevented or at least reduced by using the manipulation technique of withdrawing the pushrod  150  after placement in the vein B but prior to releasing the implant  10 , as described above with respect to  FIGS. 21 and 22 , to shorten the implant, increase the packing density of implant material, radially expand the implant, and/or increase the radially outward force exerted by the implant body on the inner wall of the HAS or vein near the sapheno-femoral junction H while reducing longitudinal tension in the portion of the implant positioned in the saphenous vein. 
       FIGS. 42-57  illustrate alternate embodiments of implants that can effectively prevent or at least reduce the potential for blood leakage around or through the implant without requiring manipulation of a pushrod. Rather, the implants can be augmented to locally bulk the implant, shorten the implant, increase the packing density of implant material, radially expand the implant, and/or increase the radially outward force exerted by the implant body on the inner wall of the HAS or vein near the sapheno-femoral junction H. 
       FIG. 42  illustrates one embodiment of an implant  300  for occlusion of a hollow anatomic structure that can effectively prevent or at least reduce the potential for blood leakage around or through an implant without requiring manipulation of a pushrod. The implant  300  can be employed in place of implant  10  of  FIG. 2  in the system  45  of  FIG. 4 , the system  190  of  FIG. 26 , or any other suitable system. The implant  300  can be similar in structure, function, and method of use to the implant  10 , except as further described herein. The depicted implant  300  comprises a bioresorbable body  302 . The body  302  can comprise a bioresorbable material in fibrous form that can be similar or identical to the material and construction of the body  12  of implant  10 , and will therefore not be further described for this embodiment. For example, as shown in the illustrated embodiment, the body  302  can naturally assume an expanded condition and convert to a compressed condition upon application of a compressive force or upon placement in a confined space such as a blood vessel lumen. Alternatively, the body  302  can naturally assume a compressed condition and convert to an expanded condition upon application of an expansive force. 
     The implant  300  further includes a tether  304  coupled to the body  302 . As one example, the body  302  can be generally elongated with a distal end  306  and a proximal end  308 , the distance between the distal end  306  and the proximal end  308  (i.e., the length of the body  302 ) optionally being greater than the cross-sectional diameter of the body  302 , and the tether  304  is coupled near or to the distal end  306  of the body  302 . The tether  304  can be coupled to the body  302  in any suitable manner, examples of which include tying or stitching the tether  304  to the body  302 , employing a coupling agent, such as a bioresorbable or non-bioresorbable adhesive, and making the tether  304  integral with the body  302 . In the embodiment of  FIG. 42 , the tether  304  is coupled to the body  302  by tying the tether  304  around the body  302  near a center of the length of the body  302 , and the body  302  is bent or turned where the tether  304  is coupled to the body  302  such that the body  302  is folded upon itself. As a result of this configuration, the coupling location of the tether  304 , or the tie point  310 , generally forms the distal end  306  of the body  302 , and the free ends of the body  302  folded upon each other form the proximal end  308  of the body  302 . The tether  304  can have any suitable length relative to the length of the body  302 . For example, the length of the tether  304  can be greater than, equal to, or less than that of the body  302 . The material and construction of tether  304  can be similar or identical to the material and construction of the tether  14  of implant  10 , and will therefore not be further described for this embodiment. 
     The implant  300  can further include force application points coupled to the body  302  and interacting with the tether  304  to apply force to the body  302  when force is applied to the tether  304 . One example of a force application point is a band coupled to and encircling the body  302 . In the embodiment of  FIG. 42 , the implant  300  includes multiple spaced bands in the form of a distal tack  312  and a proximal tack  314  coupled to the body  302 . The tacks  312 ,  314  can be coupled to the body  302  in any suitable manner, examples of which include tying or stitching the tacks  312 ,  314  to the body  302 , employing a coupling agent, such as a bioresorbable or non-bioresorbable adhesive, and making the tacks  312 ,  314  integral with the body  302 . In the embodiment of  FIG. 42 , the tacks  312 ,  314  are coupled to the body  302  by tying; both tacks  312 ,  314  are tied around the body  302  near the distal end  306 , with the distal tack  312  being closer to the distal end  306  than the proximal tack  314 . 
     Each tack  312 ,  314  can be bioresorbable and made of the same material as the body  302  or of a material different than that of the body  302 . Alternatively, the tacks  312 ,  314  can be non-bioresorbable. Further, the tacks  312 ,  314  can be inelastic or elastic. In the illustrated embodiment of  FIG. 42 , the tacks  312 ,  314  comprise a loop or ring of bioresorbable thread tied around the body  302 . Each tack  312 ,  314  can be looped around the body  302  one or more times. Preferably, the tacks  312 ,  314  are fixed and immovable relative to the fibers of the implant body  302 . In other words, the tacks  312 ,  314  preferably cannot “slip” or slide along the fibers of the body  302  when forces are applied to the tacks  312 ,  314 . However, as discussed in further detail below, the tacks  312 ,  314  preferably can move relative to each other or relative to the distal end  306  as the body  302  compresses (or bunches) longitudinally, or elongates. 
     The pushrod  150  can facilitate the bulking/augmentation of the implant  300  by holding the distal tack  312  via the wire  168 . As illustrated, the distal tack  312  can encircle the pushrod  150  beneath the wire  168  such that the implant retaining portion  170  ( FIG. 11 ) attaches the distal tack  312  to the pushrod  150 . Alternatively, the distal tack  312  can encircle just the wire  168  for a similar effect. In either configuration, detachment of the wire  168  from the distal plug  166  and its subsequent retraction through openings  160 ,  162  (see  FIG. 11 ) is uninhibited by the distal tack  312 . 
     In the embodiment of  FIG. 42 , the portion of the tether  304  extending from the tie point  310  sequentially extends generally proximally from the tie point  310 , through the proximal tack  314 , thus reversing direction and extending generally distally back toward the distal end  306 , through the distal tack  312 , reversing direction once again and extending generally proximally from the distal tack  312  along the body  302 . As a result of this configuration, the tether  304  forms a loop  316  that is adjustably-sized. Applying a proximal force to the tether  304 , such as by pulling the tether  304 , reduces the size of the loop  316  and moves the tacks  312 ,  314  toward each other. 
     The tacks  312 ,  314  and loop  316  create an augmentation zone  318 , which is an area of the body  302  generally between the tacks  312 ,  314  that can selectively be augmented in order to locally increase the radial size and/or material density of the body  302 , or shorten the implant, increase the packing density of implant material, radially expand the implant, or increase the radially outward force exerted by the implant body on the inner wall of the HAS or vein in the zone  318 . The augmentation zone  318  is selectively configurable in an unaugmented configuration, shown in  FIG. 42 , and an augmented configuration, shown in  FIG. 43 . In the unaugmented configuration, the augmentation zone  318  can have dimensions (e.g. radial size) and/or material density generally similar to the rest of the body  302 . In the augmented configuration, the augmentation zone  318  can have increased cross-sectional area and/or material density, while exerting a larger radially outward force against the inner walls of the HAS in comparison with the rest of the body  302 . In the example shown in  FIG. 43 , the body  302  in the augmentation zone  318  has both increased cross-sectional area and density in the augmented configuration. The distance between the distal tack  312  and the proximal tack  314  can directly relate to the degree of localized augmentation possible for the implant  300 . A smaller distance between the tacks  312 ,  314  results in less localized augmentation, while a greater distance between the tacks  312 ,  314  results in more localized augmentation. 
     The tether  304  acts as an actuator for the augmentation zone  318  and can be used to selectively configure the augmentation zone  318  in the augmented configuration. Specifically, pulling the tether  304  proximally reduces the size of the loop  316 , which causes the proximal tack  314  to move relative to the distal tack  312  such that the distance between the tacks  312 ,  314  is reduced. This causes the body  302  to locally “bulk up” by increasing in cross-sectional area and/or density of the body  302  in the augmentation zone  318 , as illustrated in  FIG. 43 . Pulling the tether  304  can cause the proximal tack  314  to move distally, while the distal tack  312  stays relatively stationary due to its coupling with the pushrod  150 . Alternately, if the distal tack  312  is not coupled with the pushrod  150 , pulling the tether  304  can cause the distal tack  312  to move proximally, while the proximal tack  314  stays relatively stationary. In many cases, the former may be preferred, since the localized bulking or augmentation of the body  302  can be maintained closer to the sapheno-femoral junction H. 
     The pushrod  150  can further facilitate the bulking/augmentation of the implant  300  by holding the distal portion or end  306  of the implant  300 , in addition to or instead of holding the distal tack  312 , via the wire  168 . The pushrod  150  and wire  168  thus prevent proximal movement of the distal portion or end  306  of the implant  300  as the tether  304  is pulled proximally. Thus, rather than simply moving the entire implant  300  proximally, the proximal pulling of the tether  304  takes up the “slack” in the tether forming the loop  316 , resulting in augmentation of the body  302 . 
     In various embodiments, the practitioner can grip the pushrod  150  (e.g., a portion proximal of the zone  318 ), to prevent proximal movement of the pushrod  150  and implant  300 , while pulling the tether  304  proximally. Alternatively, the practitioner can push the pushrod  150  slightly in the distal direction while pulling the tether  304 , or rely on non-manual means such as a clamp, or the inertia of and friction in the delivery system (e.g. the system  46 / 190 ), to prevent proximal movement of the implant  300  and pushrod  150  while pulling the tether  304  proximally to augment the implant  300 . Alternatively, instead of being manually gripped by the practitioner, any of the above can be accomplished by a motorized or non-motorized drive system, gear train, mechanism, etc. that grips or engages the pushrod  150  and is operated by the practitioner. 
     One embodiment of a method of using of the implant  300  is described below. While the implant  300  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. It will also be understood that while the implant  300  is described for use with the system  46 , the methods can also be modified or adapted, as necessary, for use with embodiments of the system  46  other than the embodiment employed in the following description. Aspects of the method of use of the implant  300  that overlap with the method of use of the implant  10 , described above, will be briefly summarized, but will not be described in detail. Generally, the method of use of the implant  300  can be similar to the use of the implant  10 , except as further described herein. In the description of the method, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system, etc. 
     In one embodiment of a method of use of the implant  300 , the various stages of the method proceed as depicted for implant  10  as shown in  FIGS. 15-22 . Release of the implant  300  from the pushrod  150  proceeds generally as described above for implant  10  with respect to  FIGS. 21 and 22 , with the added step that the pushrod  150  slides through and out of the distal tack  312  as it is withdrawn. The distal tack  312  can encircle the pushrod  150  with sufficient clearance to allow the pushrod  150  to slide out of the distal tack  312  as it is retracted from the vein B. 
       FIG. 44  illustrates the implant  300  in the greater saphenous vein B before release of the implant  300  and removal of the pushrod  150  from the vein B. Initially, the augmentation zone  318  is in the unaugmented configuration, as shown in  FIG. 44 . The practitioner then applies a proximal force to the tether  304 , such as by pulling on the proximal end of the tether  304 , thereby reducing the size of the loop  316  and moving the distal and proximal tacks  312 ,  314  relative to each other such that the distance between the tacks  312 ,  314  is reduced. The pushrod  150  and wire  168 , assisted by any force applied thereto or anchoring of a proximal portion of the pushrod, prevent proximal movement of the implant  10  as the proximal force  314  is applied to the tether  304 . The pulling and loop-reduction action places the augmentation zone  318  in the augmented configuration, as shown in  FIG. 45 . With the augmentation zone  318  in the augmented configuration as shown in  FIG. 45 , the implant  300  prevents or at least reduces the potential for blood leakage around or through the implant  300  by locally bulking or augmenting the body  302  (e.g., radially expanding the body, increasing the density of material in the body, and/or increasing the radially outward force exerted by the body on the inner wall of the HAS or vein) within the vein B near the sapheno-femoral junction H. The practitioner can then optionally secure the implant  300  to the leg A, as described above with respect to  FIGS. 24 and 24A . 
       FIG. 46  depicts another embodiment of an implant  300  which can be similar in structure, function and method of use to the implant  300  of  FIGS. 42-45 , except as further described herein. As illustrated, the proximal tack  314  encircles the pushrod  150  as well as the body  302 . Therefore, the proximal tack  314  can cooperate with the distal tack  312  to hold the body  302  against the pushrod  150 . Detachment of the wire  168  from the distal plug  166  and its subsequent retraction through openings  160 ,  162  (see  FIG. 11 ) is uninhibited by the tacks  312 ,  314 . Release of the implant  300  from the pushrod  150  proceeds generally as described above for implant  10  with respect to  FIGS. 21 and 22 , with the added step that the pushrod  150  slides through and out of the tacks  312 ,  314  as it is withdrawn. The tacks  312 ,  314  can encircle the pushrod  150  with sufficient clearance to allow the pushrod  150  to slide out of the tacks  312 ,  314  as it is retracted from the vein B. 
     The augmentation zone  318  can be actuated before the release of the implant  300  from the pushrod  150 , as shown in  FIG. 47 , thereby placing the augmentation zone  318  in the augmented configuration. Applying a proximal force to the tether  304 , such as by pulling, reduces the size of the loop  316 , which causes the tacks  312 ,  314  to move relative to each other such that the distance between the tacks  312 ,  314  is reduced. At this time, the proximal tack  314  will also move relative to the pushrod  150 , such as by sliding along the pushrod  150 . Otherwise, the process can proceed generally as described above for the embodiment shown in  FIGS. 42-45 . 
       FIG. 48  depicts another embodiment of an implant  300  which can be similar in structure, function and method of use to the implant  300  of  FIGS. 42-45 , except as further described herein. The implant  300  includes at least one intermediate tack between the distal and proximal tacks  312 ,  314 . As illustrated, implant  300  includes a first intermediate tack  320  and a second intermediate tack  322 , with the second intermediate tack  322  adjacent to and spaced proximally from the distal tack  312 , the first intermediate tack  320  adjacent to and spaced proximally from the second intermediate tack  322 , and the proximal tack  314  adjacent to and spaced proximally from the first intermediate tack  320 . 
     In this embodiment, the distal end  306  is at or near the coupling location of the distal tack  312  rather than the tie point of the tether  304 . The distal tack  312  is coupled to the body  302  near a center of the length of the body  302 , and the body  302  is bent or turned where the distal tack  312  is coupled to the body  302  such that the body  302  is folded upon itself. As a result of this configuration, the coupling location of the distal tack  312  forms the distal end  306  of the body  302 , and the free ends of the body  302  folded upon each other form the proximal end  308  of the body  302 . 
     The tether  304  is coupled to the proximal tack  314  at a tie point  324  and looped through the remaining tacks  312 ,  320 ,  322  to create three distinct augmentation zones; a first augmentation zone  326  generally between the proximal tack  314  and the first intermediate tack  320 , a second augmentation zone  328  generally between the first and second intermediate tacks  320 ,  322 , and a third augmentation zone  330  generally between the second intermediate tack  322  and the distal tack  312 . The portion of the tether  304  extending from the tie point  324  extends generally distally from the proximal tack  314 , sequentially through the first intermediate tack  320 , the second intermediate tack  322 , and the distal tack  312 , and then generally proximally from the distal tack  312  along the body  302 . As a result of this configuration, the tether  304  does not form a loop, but rather has an adjustable length between the tie point  324  and the distal tack  312 . Applying a proximal force to the tether  304 , such as by pulling the tether  304 , reduces the length of the tether between the tie point  342  and the distal tack  312 . 
     Each augmentation zone  326 ,  328 ,  330  is configurable in an unaugmented configuration, shown in  FIG. 48 , and an augmented configuration, shown variously in  FIGS. 49-51 . The tether  304  acts as an actuator for all three augmentation zones. As illustrated in  FIG. 49 , pulling the tether  304  initially causes at least the proximal tack  314  and the first intermediate tack  320  to move relative to each other; for example, the proximal tack  314  can be pulled distally toward the first intermediate tack  320 . This action places the first augmentation zone  326  in the augmented configuration. As illustrated in  FIG. 50 , continued pulling of the tether  304  causes at least the first and second intermediate tacks  320 ,  322  to move relative to each other; for example, the first intermediate tack  320  can be pulled distally toward the second intermediate tack  322 . This action places the second augmentation zone  328  in the augmented configuration. As illustrated in  FIG. 51 , continued pulling of the tether  304  causes at least the second intermediate tack  322  and distal tack  312  to move relative to each other; for example, the second intermediate tack  322  can be pulled distally toward the distal tack  312 . This action places the third augmentation zone  330  in the augmented configuration. 
     While the drawings show the sequential actuation of the augmentation zones  326 ,  328 ,  330 , it will be understood from the drawings and the description that there may be some overlap between the actuation of the augmentation zones, and that the augmentation zones may be actuated generally simultaneously with each other. Furthermore, less than all of the augmentation zones can be actuated by exerting less pulling action on the tether  304 . For example by only pulling the tether  304  a short distance, the first augmentation zone  326  may be actuated, but not the second or third augmentation zones  328 ,  330 . Further, while three augmentation zones are illustrated in the drawings, any number of zones can be provided by including additional tacks on the body  302  and following the tethering pattern shown in the figures. 
     In addition to the embodiment having multiple augmentation zones shown in  FIGS. 48-51 , the arrangement depicted (wherein the tether  304  is fixed to the proximal tack  314 , extends distally and passes through the distal tack  312  coupled to the distal end of the implant body  302  before extending proximally along the body  302 ) can be employed in an implant  300  having a single augmentation zone, between the distal and proximal tacks  312 ,  314 . 
     The use of multiple augmentation zones, as seen in  FIGS. 48-57 , advantageously facilitates the formation of an augmented region of the implant which is greater in overall length than in a single-zone implant, while controlling the radial expansion of the implant and the shape of the augmentation zone when expanded. Instead of a relatively short zone of very wide radial expansion, a relatively long zone of moderate radial expansion can be formed. 
       FIG. 52  depicts another embodiment of an implant  300  which can be similar in structure, function and method of use to the implants  300  of  FIGS. 42-51 , except as further described herein. The implant  300  includes at least one intermediate tack between the distal and proximal tacks  312 ,  314 . As illustrated, implant  300  includes a single intermediate tack  336  between and spaced from the distal and proximal tacks  312 ,  314 . Further, all of the tacks  312 ,  314 ,  336  are coupled to the pushrod  150  as well as the body  302 , as described above with reference to  FIG. 46 . 
     The tether  304  is coupled to the body  302  at the distal tie point  310  and is looped through the tacks  312 ,  314 ,  336  to create two augmentation zones; a first augmentation zone  338  generally between the proximal tack  314  and the intermediate tack  336 , and a second augmentation zone  340  generally between the intermediate tack  336  and the distal tack  312 . The portion of the tether  304  extending from the tie point  310  sequentially extends generally proximally from the tie point  310 , through the proximal tack  314 , through the intermediate tack  336 , through the distal tack  312 , and generally proximally from the distal tack  312  along the body  302 . As a result of this configuration, the tether  304  forms loop  316 . 
     Each augmentation zone  338 ,  340  is configurable in an unaugmented configuration, shown in  FIG. 52 , and an augmented configuration, shown variously in  FIGS. 53 and 54 . The tether  304  acts as an actuator for both augmentation zones. As illustrated in  FIG. 53 , pulling the tether  304  initially begins to reduce the size of the loop  316 , which causes at least the proximal tack  314  and the intermediate tack  336  to move relative to each other; for example, the proximal tack  314  can be pulled distally toward the intermediate tack  336 . This action places the first augmentation zone  338  in the augmented configuration. At this time, at least one of the tacks  314 ,  336  will also move relative to the pushrod  150 , such as by sliding along the pushrod  150 . As illustrated in  FIG. 54 , continued pulling of the tether  304  further reduces the size of the loop, which causes at least the intermediate tack  336  and the distal tack  312  to move relative to each other; for example, the intermediate tack  336  can be pulled distally toward the distal tack  312 . This action places the second augmentation zone  340  in the augmented configuration. At this time, the intermediate tack  336  will also move relative to the pushrod  150 , such as by sliding along the pushrod  150 . 
     While the drawings show the sequential actuation of the first and second augmentation zones  338 ,  340 , it will be understood from the drawings and the description that there may be some overlap between the actuation of the augmentation zones, and that the augmentation zones may be actuated generally simultaneously with each other. Furthermore, less than all of the augmentation zones can be actuated by exerting less pulling action on the tether  304 . For example by only pulling the tether  304  a short distance, the first augmentation zone  338  may be actuated, but not the second augmentation zone  340 . Further, while two augmentation zones are illustrated in the drawings, any number of zones can be provided by including additional tacks on the body  302  and following the tethering pattern shown in the figures. 
       FIG. 55  depicts another embodiment of an implant  300  which can be similar in structure, function and method of use to the implants  300  of  FIGS. 42-54 , except as further described herein. The implant  300  includes multiple tethers coupled to the body  302 . As illustrated, the implant  300  includes two tethers  304 ,  342 , each of which is coupled to the body  302  at the distal tie point  310 . In  FIGS. 55-57 , the first tether  304  is drawn in solid line, while the second tether  342  is drawn in dotted line to help distinguish it from the first tether  304 ; however, the tethers  304 ,  342  can have the same structure and be made from the same material. 
     The tethers  304 ,  342  are looped through the tacks  312 ,  314 ,  336  to create the two augmentation zones  338 ,  340 . The portion of the first tether  304  extending from the tie point  310  sequentially extends generally proximally from the tie point  310 , through the proximal tack  314 , generally distally back toward the distal end  306 , through the distal tack  312 , and generally proximally from the distal tack  312  along the body  302 . As a result of this configuration, the first tether  304  forms a first loop  316  that is adjustably-sized. The portion of the second tether  342  extending from the tie point  310  sequentially extends generally proximally from the tie point  310 , through the intermediate tack  336 , generally distally back toward the distal end  306 , through the distal tack  312 , and generally proximally from the distal tack  312  along the body  302 . As a result of this configuration, the second tether  342  forms a second loop  344  that is adjustably-sized. Pulling proximally on either tether  304 ,  342  reduces the size of the respective loop  316 ,  344 . 
     The tethers  304 ,  342  act as actuators for their respective augmentation zones  338 ,  340 , which can be actuated independently of each other with the illustrated embodiment of the implant  300 . As illustrated in  FIG. 56 , pulling the first tether  304  reduces the size of the first loop  316 , which causes the proximal tack  314  and the intermediate tack  336  to move relative to each other; for example, the proximal tack  314  can be pulled distally toward the intermediate tack  336 . This action places the first augmentation zone  338  in the augmented configuration. At this time, at least one of the tacks  314 ,  336  will also move relative to the pushrod  150 , such as by sliding along the pushrod  150 . As illustrated in  FIG. 57 , pulling the second tether  342  reduces the size of the second loop  344 , which causes the intermediate tack  336  and the distal tack  312  to move relative to each other; for example, the intermediate tack  336  can be pulled distally toward the distal tack  312 . This action places the second augmentation zone  340  in the augmented configuration. At this time, the intermediate tack  336  will also move relative to the pushrod  150 , such as by sliding along the pushrod  150 . 
     While the drawings show the independent, sequential actuation of the first and second augmentation zones  338 ,  340 , it will be understood from the drawings and the description that the zones can be actuated in any sequence, or that the zones may be actuated generally simultaneously with each other by pulling the tethers  304 ,  342  at the same time. Further, while two augmentation zones are illustrated in the drawings, any number of zones can be provided by including additional tacks and tethers on the body  302  following the tethering pattern shown in the figures. 
       FIGS. 58-61  illustrate another embodiment of an introducer or pushrod  350  for introducing an implant, such as implant  10  or implant  300 , into a hollow anatomic structure.  FIG. 58  is an enlarged sectional view of the proximal end of the pushrod  350 . The pushrod  350  can be employed in place of pushrod  150  of  FIG. 11  in the system  45  of  FIG. 4 , the system  190  of  FIG. 26 , or any other suitable system. The pushrod  350  can be similar in structure, function, and method of use to the pushrod  150 , except as further described herein. 
     The pushrod  350  terminates at a distal tip region  352 , which includes a single opening  354  that provides access to an internal lumen  356  that terminates at a distal plug  358 . A wire  360  resides within the lumen  356  except for an implant retaining portion  362  located externally of the lumen  356  adjacent the opening  354 . The wire  360  exits and enters the lumen  356  through the opening  354  to form the implant retaining portion  362 . 
     The opening  354  is made by forming a cut in the side wall of the pushrod  350 , and includes a distal end  364  and a proximal end  366 . When viewed from the side, as shown in  FIG. 58 , the side profile of the opening  354  gradually rises toward the proximal and distal ends  364 ,  366  such that both ends  364 ,  366  are nearly flush with the side wall of the pushrod  350 , and the pushrod  350  has its full sidewall thickness at either end  364 ,  366  of the opening  354 . The opening  354  can further have an elliptical profile at both ends  364 ,  366 ; or, alternatively each end can have a “wedge” profile wherein the adjacent upper edge of the pushrod sidewall is straight but angled with respect to the longitudinal axis of the pushrod, giving the opening  354  a shallow or flat-bottomed “V” configuration when viewed from the side as in  FIG. 58 . Furthermore, the edges of the opening  354  can be deburred during manufacture of the pushrod  350  so that they are relatively smooth, with no rough or sharp corners. These features of the opening  354 —flush ends, gently sloping (e.g. elliptical or double-wedge) profile, and deburred edges—reduce the possibility of snagging a portion of the implant on the pushrod  350  when withdrawing the pushrod  350  from the vein or other HAS. 
     The above-described profiles for the opening  354  provide a gently sloping and gradual transition from the deep central portion of the opening  354  to the shallow or flush distal or proximal end of the opening. This reduces the tendency of the pushrod to snag the implant after the wire  360  has been retracted to release the implant. As the pushrod is withdrawn, the sloping sidewall edge adjacent the opening  354  gently urges the implant material to the side of the pushrod, allowing the pushrod to pass in the proximal direction without snagging the implant at the distal end of the opening  354  and inadvertently pulling the implant in the proximal direction. 
     With reference to  FIG. 60 , which illustrates the distal end of the pushrod  350  and the implant  10  within the greater saphenous vein B, the implant retaining portion  362  attaches the implant  10  to the pushrod  350  for cooperative movement during advancement of the pushrod  350 . In the illustrated embodiment, the implant  10  attaches to the implant retaining portion  362  at the distal end  16  of the body  12  at or near where the tether  14  connects to the body  12 . In particular, the distal end  16  is held between the implant retaining portion  362  of the wire  360  and the portion of the pushrod  350  defining the opening  354 . In this configuration, the tether  14  and about half of the length of the body  12  are located on one side of the wire  360  and the other half of the length of the body  12  are located on the opposite side of the wire  360 . The body  12  wraps around the wire  360  such that the free ends of the body  12  are folded upon each other form the proximal end  18  of the body  12 , as described above. The implant retaining portion  362  thus forms a closed noose or snare around the implant  10  that permits the implant  10  to be retained whether the pushrod  350  is pushed distally or pulled proximally. This in turn facilitates use of the pushrod  350  either to push the implant  10  distally, or pull the implant  10  proximally, even when the implant is in a tightly confined space such as an HAS lumen or a sheath lumen. “Pull” functionality can be useful to longitudinally compress, radially expand, increase the density of, and increase the radial outward force applied by, the implant by slightly retracting the pushrod after insertion of the implant, as discussed above. The implant retaining portion  362  can further be configured to hold the implant  10  against the portion of the pushrod  350  adjacent the opening  354  tightly enough to prevent shifting of the implant  10 . The above-described attachment of the implant  10  and the pushrod  350  provides an exemplary manner of attachment; the implant  10  and the pushrod  350  can be joined in any suitable manner and are not limited to that described above and shown in the figures. 
     One embodiment of a method of use of the pushrod  350  is described below. While the pushrod  350  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. It will also be understood that while the pushrod  350  is described for use with the system  46 , the methods can also be modified or adapted, as necessary, for use with embodiments of the system  46  other than the embodiment employed in the following description. Aspects of the method of use of the pushrod  350  that overlap with the method of use of the pushrod  150 , described above, will be briefly summarized, but will not be described in detail. Generally, the method of use of the pushrod  350  can be similar to the use of pushrod  150 , except as further described herein. In the description of the method, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system, etc. 
     In one embodiment of a method of use of the pushrod  350 , the various stages of the method can proceed as depicted for implant  10  as shown in  FIGS. 15-20 .  FIG. 60  illustrates the pushrod  350  and implant  10  in the greater saphenous vein B after removal of the introducer sheath  20  from the vein B. The practitioner applies a proximal force to the wire  360 , such as by pulling on the proximal end of the wire  360 , thereby detaching the wire  360  from the distal plug  358 . Continued application of the proximal force retracts the wire  360  through the opening  354  and releases the implant  10  from between the wire  360  and the pushrod  350 , as illustrated in  FIG. 61 . The wire  360  can be retracted any desired distance corresponding to releasing the implant  10  from the pushrod  350 . For example, the wire  360  need not be retracted past the proximal end  366  of the opening  354  if pulling the wire  360  only partly back from the distal end  364  of the opening  354  effects release of the implant  10 . Retraction of the wire  360  removes the implant retaining portion  362  from the implant  10  and gives the pushrod  350  a lower profile for withdrawal since the wire  360  is contained within the circumferential profile of the pushrod  350 . In other words, the pushrod  350  takes on a withdrawal profile upon retraction of the wire  360  into the pushrod lumen as seen in  FIG. 61 . The pushrod  350  (and the pushrods  150 ,  370 ,  390 ) advantageously achieves a withdrawal profile along its entire working length (the portion that enters, or is configured to enter, the sheath or HAS during use) which is no larger than the outer circumference (or other outer perimeter) of the pushrod sidewalls when viewed in cross-section (taken orthogonal to the longitudinal axis of the pushrod  350 ). This in turn reduces the chance of undesirably snagging and pulling the implant proximally when retracting the pushrod. 
     The practitioner follows release of the implant  10  with retraction of the pushrod  350  from the vein B and the remaining stages of the method proceed as shown in  FIGS. 23-24A . Features of the pushrod  350 , including the flush proximal and distal ends  364 ,  366  on the opening  354 , the elliptical profile of the opening  354 , the deburred edges of the opening  354 , the removal of the implant retaining portion  362  when releasing the implant  10 , and the lower profile during pushrod removal, reduce the possibility of snagging the implant  10  on the pushrod  350  as the pushrod  350  is retracted from the vein B. 
       FIGS. 62-65  illustrate another embodiment of an introducer or pushrod  370  for introducing an implant, such as implant  10  or implant  300 , into a hollow anatomic structure, and can be similar in structure, function and method of use to the pushrod  150  of  FIG. 11  or the pushrod  350  of  FIG. 58 , except as further described herein.  FIG. 62  is an enlarged sectional view of the proximal end of the pushrod  370 . The pushrod  370  terminates at a distal tip region  372 , which includes a single opening  374  that provides access to an internal lumen  376  that terminates at an open distal end  378 . A through-hole  380  is formed in the sidewall of the pushrod  370  adjacent to the open distal end  378 . A wire  382  resides within the lumen  376  except for an implant retaining portion  384  located externally of the lumen  376  adjacent the opening  374 . The wire  382  exits the lumen  376  through the opening  374  and is captured by the through-hole  380  to form the implant retaining portion  384 . The implant retaining portion  384  is formed closer to the distal end of the pushrod  370  as compared with other embodiments of pushrods shown herein. This permits an implant to be held closer to the distal end of the pushrod  370 , as discussed in further detail below. 
     The distal end of the wire  382  is removably retained by the through-hole  380  such that the wire  382  separates from the through-hole  380  upon application of a suitable proximal force to the wire  382 . Continuation of the proximal force pulls the wire  382  through the opening such that the distal end of the wire  382  resides within the lumen  376  proximally of the opening  374 . The proximal force can be applied by, for example, the practitioner pulling on the wire  382 , in which case, a proximal end of the wire  382  can project from the pushrod  370 , such as through the proximal end of the pushrod  370  (not shown). The type and degree of attachment between the wire  382  and the through-hole  380  can be selected according to a desired proximal force required to effect separation of the wire  382  from the through-hole  380 . As an example, the wire  382  can be fit into to the through-hole  380  and retained by friction. Alternatively, the wire  382  can be attached to the through-hole  380  with an adhesive or by chemical joining processes, including various types of welding. 
     The opening  374  is made by forming a cut in the side wall of the pushrod  370 , and includes a distal end  386  and a proximal end  388 . When viewed from the side, as shown in  FIG. 62 , the side profile of the opening  374  gradually rises from the distal end  386  toward the proximal end  388  such that the proximal end  388  is nearly flush with the side wall of the pushrod  370 , and the pushrod  370  has its full sidewall thickness at the proximal end  388  of the opening  374 . When viewed from the top, as shown in  FIG. 63 , which does not show the wire  382  for clarity purposes, the opening  374  further has an elliptical profile at the proximal end  388 . Furthermore, the edges of the opening  374  can be deburred during manufacture of the pushrod  370  so that they are relatively smooth, with no rough or sharp corners. These features of the opening  375 —flush proximal end  388 , elliptical profile, and deburred edges—reduce the possibility of snagging an implant on the pushrod  370 . 
     With reference to  FIG. 64 , which illustrates the distal end of the pushrod  370  and the implant  10  within the greater saphenous vein B, the implant retaining portion  384  attaches the implant  10  to the pushrod  370  for cooperative movement during advancement of the pushrod  370 . In the illustrated embodiment, the implant  10  attaches to the implant retaining portion  384  at the distal end  16  of the body  12  at or near where the tether  14  connects to the body  12 . In particular, the distal end  16  is held between the implant retaining portion  384  of the wire  382  and the portion of the pushrod  370  defining the opening  374 . In this configuration, the tether  14  and about half of the length of the body  12  are located on one side of the wire  382  and the other half of the length of the body  12  are located on the opposite side of the wire  382 . The body  12  wraps around the wire  382  such that the free ends of the body  12  are folded upon each other form the proximal end  18  of the body  12 , as described above. The implant retaining portion  384  forms a closed noose or snare around the implant  10  that permits the implant  10  to be retained whether the pushrod  370  is pushed distally or pulled proximally, thereby providing the push-pull functionality discussed above. The implant retaining portion  384  can further be configured to hold the implant  10  against the portion of the pushrod  370  adjacent the opening  374  tightly enough to prevent shifting of the implant  10 . The above-described attachment of the implant  10  and the pushrod  370  provides an exemplary manner of attachment; the implant  10  and the pushrod  370  can be joined in any suitable manner and are not limited to that described above and shown in the figures. 
     The implant  10  attaches to the pushrod  370  closely to the distal end of the pushrod  370  due to the arrangement of the implant retaining portion  384  and the through-hole  380 . This reduces the “dead space” associated with the pushrod  370 , which is any portion of a pushrod that extends distally beyond an implant attached to the pushrod. For the present embodiment, the dead space can be approximately equivalent to the distance between the open distal end  378  and the implant retaining portion  384 . Reduction of dead space is advantageous because it allows the practitioner to place an implant very close to the sapheno-femoral junction H without extending the pushrod  370  into the femoral vein G, which may carry a risk of abrading or puncturing the femoral vein G and injuring the patient, or of generating thrombosis within the femoral vein. 
     One embodiment of a method of use of the pushrod  370  is described below. While the pushrod  370  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. It will also be understood that while the pushrod  370  is described for use with the system  46 , the methods can also be modified or adapted, as necessary, for use with embodiments of the system  46  other than the embodiment employed in the following description. Aspects of the method of use of the pushrod  370  that overlap with the method of use of the pushrod  150 , described above, will be briefly summarized, but will not be described in detail. In the description of the method, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system, etc. 
     In one embodiment of a method of use of the pushrod  370 , the various stages of the method can proceed as depicted for implant  10  as shown in  FIGS. 15-20 .  FIG. 64  illustrates the pushrod  370  and implant  10  in the greater saphenous vein B after removal of the introducer sheath  20  from the vein B. The practitioner applies a proximal force to the wire  382 , such as by pulling on the proximal end of the wire  382 , thereby detaching the wire  382  from the through-hole  380 . Continued application of the proximal force retracts the wire  382  through the opening  374  and releases the implant  10  from between the wire  382  and the pushrod  370 , as illustrated in  FIG. 65 . The wire  382  can be retracted any desired distance corresponding to releasing the implant  10  from the pushrod  370 . For example, the wire  382  need not be retracted past the proximal end  388  of the opening  374  if pulling the wire  384  only partly back from the distal end  386  of the opening  374  effects release of the implant  10 . Retraction of the wire  382  removes the implant retaining portion  384  from the implant  10  and gives the pushrod  370  a lower profile since the wire  382  is contained within the circumferential profile of the pushrod  370 . As discussed above with respect to the pushrods  350  and  150 , a withdrawal profile is achieved with the pushrod  370  in which no portion of the pushrod protrudes radially beyond the outer circumference (or other outer perimeter) of the pushrod sidewall. This withdrawal profile advantageously prevails along the working length of the pushrod. The practitioner follows release of the implant  10  with retraction of the pushrod  370  from the vein B and the remaining stages of the method proceed as shown in  FIGS. 23-24A . Features of the pushrod  370 , including the flush proximal end  388  on the opening  374 , the elliptical profile of the opening  374 , the deburred edges of the opening  374 , the removal of the implant retaining portion  384  when releasing the implant  10 , and the low withdrawal profile during pushrod removal, reduce the possibility of snagging the implant  10  on the pushrod  370  as the pushrod  370  is retracted from the vein B. Furthermore, the dead space associated with the pushrod  370  is reduced by attaching the implant close to the distal end of the pushrod  370 . 
       FIGS. 66-69  illustrate another embodiment of an introducer or pushrod  390  for introducing an implant, such as implant  10  or implant  300 , into a hollow anatomic structure, and can be similar in structure, function and method of use to the pushrods  150 ,  350 ,  370 , except as further described herein.  FIG. 66  is an enlarged sectional view of the distal end of the pushrod  390 . The pushrod  390  terminates at a distal tip region  392 , which includes a single sidewall opening  394 . A wire  400  resides within the lumen  396  and forms an implant retaining portion  402  adjacent the opening  394 . The wire  400  is relatively straight, with little or no curvature in the implant retaining portion  402  or other portion of the wire  400 . Employing the straight or only slightly curved wire  400  can afford greater flexibility in selecting a material for the wire  400 . For example, stainless steel is a suitable material for the wire  400 , whereas it may not be suitable for embodiments of the pushrod having a relatively highly curved wire (e.g. forming a highly curved implant retaining portion) since a curved stainless steel wire may plastically deform and may not straighten sufficiently to enable the wire to be retracted into the lumen  396  to release the implant. Stainless steel is also less expensive than other suitable wire materials, such as Nitinol. However, Nitinol is superelastic, and is suitable for embodiments of the pushrod having a relatively highly curved wire or retaining portion. 
     The opening  394  is made by forming a cut in the side wall of the pushrod  390 , and includes a distal end  404  and a proximal end  406 . When viewed from the side, as shown in  FIG. 66 , the proximal end  406  of the opening  394  is cut down deeper into the side wall of the pushrod  390  than the distal end  404 . The side profile of the opening  394  gradually slopes or rises from the proximal end  406  to the distal end  404  such that the distal end  404  is flush or nearly flush with the side wall of the pushrod  390 . In the depicted embodiment, the opening  394  has a curved or elliptical profile defined by the upper edge of the pushrod sidewall. Alternatively, the opening  394  can have a simpler “wedge” profile defined by a straight (but angled with respect to the longitudinal axis of the pushrod  390 ) upper edge of the pushrod sidewall. Furthermore, the edges of the opening  394  can be deburred during manufacture of the pushrod  390  so that they are relatively smooth, with no rough or sharp corners. 
     These features of the opening  394 —flush distal end  404 , sloping (e.g., curved/elliptical or wedge) profile of the opening  394 , and deburred edges—reduce the possibility of snagging an implant on the pushrod  390 . The above-described profiles for the opening  394  provide a gently sloping and gradual transition from the deep proximal portion of the opening  394  to the shallow or flush distal end of the opening. This reduces the tendency of the pushrod to snag the implant after the wire  400  has been retracted to release the implant. As the pushrod is withdrawn, the sloping sidewall edge adjacent the opening  394  (see, e.g.,  FIG. 69 ) gently urges the implant material to the side of the pushrod, allowing the pushrod to pass in the proximal direction without snagging the implant material at the distal end of the opening  394  and inadvertently pulling the implant in the proximal direction. 
     With reference to  FIG. 68 , which illustrates the distal end of the pushrod  390  and the implant  10  within the greater saphenous vein B, the implant retaining portion  402  attaches the implant  10  to the pushrod  390  for cooperative movement during advancement of the pushrod  390 . In the illustrated embodiment, the implant  10  attaches to or underlies the implant retaining portion  402  at the distal end  16  of the body  12  at or near where the tether  14  connects to the body  12 . In particular, the distal end  16  is held between the implant retaining portion  402  of the wire  400  and the portion of the pushrod  390  defining the opening  394 . In this configuration, the tether  14  and about half of the length of the body  12  are located on one side of the wire  400  and the other half of the length of the body  12  are located on the opposite side of the wire  400 . The body  12  wraps around the wire  400  such that the free ends of the body  12  are folded upon each other and form the proximal end  18  of the body  12 , as described above. The implant retaining portion  402  forms a closed noose or snare around the implant  10  that permits the implant  10  to be retained whether the pushrod  390  is pushed distally or pulled proximally. The implant retaining portion  402  can further be configured to hold the implant  10  against the portion of the pushrod  390  adjacent the opening  394  tightly enough to prevent shifting of the implant  10 . The above-described attachment of the implant  10  and the pushrod  390  provides an exemplary manner of attachment; the implant  10  and the pushrod  390  can be joined in any suitable manner and are not limited to that described above and shown in the figures. 
     One embodiment of a method of use of the pushrod  390  is described below. While the pushrod  390  can be employed in conjunction with any suitable HAS, the methods are described with respect to the greater saphenous vein B for illustrative purposes. It will be understood that the methods can be modified or adapted as necessary, if necessary, for use in other HASs. It will also be understood that while the pushrod  390  is described for use with the system  46 , the methods can also be modified or adapted, as necessary, for use with embodiments of the system  46  other than the embodiment employed in the following description. Aspects of the method of use of the pushrod  390  that overlap with the method of use of the pushrod  150 , described above, will be briefly summarized, but will not be described in detail. Generally, the method of use of the pushrod  390  can be similar to the use of the pushrods  150 ,  350  or  370 , except as further described herein. In the description of the method, the various steps are discussed in terms of being performed by the practitioner; however, it is understood that these steps may be performed by the practitioner manually or through the operation of a motorized or non-motorized drive system, etc. 
     In one embodiment of a method of use of the pushrod  390 , the various stages of the method proceed as depicted for implant  10  as shown in  FIGS. 15-20 .  FIG. 68  illustrates the pushrod  390  and implant  10  in the greater saphenous vein B after removal of the introducer sheath  20  from the vein B. The practitioner applies a proximal force to the wire  400 , such as by pulling on the proximal end of the wire  400 , thereby pulling the distal portion of the wire  400  into the pushrod lumen  396  proximal of the opening  394 . In this embodiment, since the wire  400  is kept relatively straight and has little or no curvature at the implant retaining portion  402 , a reduced proximal force can be applied to the wire  400  to pull it proximally along the lumen  396 , since the force will be more closely aligned with the axis of the wire  400  as compared with previous pushrod embodiments having curved wires. 
     Continued application of the proximal force retracts the wire  400  through the opening  394  and releases the implant  10  from between the wire  400  and the pushrod  390 , as illustrated in  FIG. 69 . The wire  400  can be retracted any desired distance corresponding to releasing the implant  10  from the pushrod  390 . For example, the wire  400  need not be retracted past the proximal end  406  of the opening  394  if pulling the wire  400  only partly back from the distal end  404  of the opening  394  effects release of the implant  10 . Retraction of the wire  400  removes the implant retaining portion  402  from the implant  10  and gives the pushrod  390  a low profile since the wire  400  is contained within the circumferential profile of the pushrod  390 . The practitioner follows release of the implant  10  with retraction of the pushrod  390  from the vein B and the remaining stages of the method proceed as shown in  FIGS. 23-24A . Features of the pushrod  390 , including the flush distal end  404  of the opening  394 , the sloping profile of the opening  394 , the deburred edges of the opening  394 , the removal of the implant retaining portion  402  when releasing the implant  10 , and the lower profile during pushrod removal, reduce the possibility of snagging the implant  10  on the pushrod  390  as the pushrod  390  is retracted from the vein B. Furthermore, the pushrod  390  requires less force to operate by employing a relatively straight wire  400 , and may cost less to manufacture since the wire  400  can be made from less expensive materials, such as stainless steel. 
     Despite the foregoing discussion of certain embodiments, only the following claims, and such other claims as may be presented in the future based on the disclosure herein (and not the present Detailed Description), are intended to define the invention(s) protected hereby.