Patent Description:
In the simplest form, these clips grasp tissue surrounding a wound, bringing edges of the wound together to allow natural healing processes to close the wound. Specialized endoscopic clipping devices are used to deliver the clips to desired locations within the body and to position and deploy the clips at the desired locations after which the clip delivery device is withdrawn, leaving the clip within the body.

Endoscopic hemostatic clipping devices are generally designed to reach tissues deep within the body (e.g., within the GI tract, the pulmonary system, the vascular system or other lumens and ducts) via a working lumen of an endoscope. Thus, the dimensions of the clipping device are limited by the dimensions of the working channels of endoscopes with which they are to be employed. <CIT> and <CIT> disclose clipping devices of the prior art.

Claim <NUM> defines the invention and dependent claims disclose embodiments. In one aspect, the present disclosure is directed to a tissue clipping apparatus comprising a flexible, elongate member, a proximal end of which remains external to the body accessible to a user while a distal end of the flexible member is inserted into the body to a location adjacent to target tissue to be clipped. A control wire extending through the flexible member in combination with a capsule is releasably coupled to a distal end of the flexible member and a clip, a proximal portion of the clip being received within the capsule. A joint releasably coupling the clip to the control wire includes a yoke extending around a proximal end of the clip and a frangible link which fails when subject to a predetermined tension to separate the clip from the control wire.

According to the embodiments of the present disclosure, a hemostatic clipping device is provided that is relatively simple to manufacture and use. Exemplary embodiments of the clipping device improve on the deployment mechanism for both single and two piece hemostatic clips as well as on the mechanism for tip-catheter separation. The embodiments also provide protection of the working channel of the endoscope from sharp edges of the clip deployment device. Examples of hemostatic clips currently employed in the field include clips such as those disclosed in <CIT> (hereinafter the '<NUM> application).

As shown in <FIG>, a clipping device <NUM> according to an exemplary embodiment of the invention deploys from within a capsule <NUM> a single piece hemostatic clip <NUM> including a pair of tissue gripping arms <NUM> to clamp tissue to, for example, clamp a wound closed to stop bleeding. The hemostatic clip <NUM> is formed of a biocompatible material including metals such as stainless steel and Nitinol, polymers, biological materials and the like, as would be understood by those skilled in the art. During an initial insertion configuration, the clip <NUM> is contained within the capsule <NUM>, constraining the arms <NUM> in a closed configuration with distal ends of the arms <NUM><NUM> in proximity to one another against a bias of the arms <NUM> which urges them apart into the open, tissue receiving configuration shown in <FIG>. Specifically, a proximal portion of the clip <NUM> is housed within the capsule <NUM> along with proximal and intermediate portions of the arms <NUM>, wherein contact between the inner walls of the capsule <NUM> and the arms <NUM> draws the arms <NUM> closed against one another. A proximal portion of the capsule <NUM> is connected to a flexible member <NUM>, which is formed, for example, as an elongated tubular structure extending to a proximal portion of the device <NUM> which remains outside the body at all times. The flexible member <NUM> may be formed as a coil or, alternatively, as any other suitable hollow, flexible structure. In an exemplary embodiment, the flexible member <NUM> is made of a suitably thin material which transmits to the distal end rotation applied in either direction to the proximal portion without substantially winding up. Specifically, rotation of the proximal portion of the device <NUM> about the longitudinal axis is transmitted along the flexible member <NUM> to the capsule <NUM> to position the clip <NUM> in an optimum orientation relative to a portion of tissue to be gripped thereby. A control wire <NUM> is slidably received within the flexible member <NUM> with a distal end thereof received within the capsule <NUM>, as will be described in greater detail below. A proximal portion of the control wire <NUM> is connected to an actuator (not shown) on the proximal portion of the device <NUM> where it remains accessible to a user throughout the procedure.

A proximal portion of the clip <NUM> may be formed in a relatively hourglass shape with a bulbed proximal end <NUM>. The bulbed shape of the proximal end <NUM> can maximize a clip-opening angle of the clip <NUM>, as those skilled in the art will understand, while the hourglass shape forms a space <NUM> within the proximal end <NUM> for receiving therein a yoke post <NUM> of a deployment mechanism. The yoke post <NUM> may be coupled to the control wire <NUM> via a yoke <NUM> and a clevis <NUM> so that movement of the control wire <NUM> proximally and distally through the flexible member <NUM> facilitates contact between the yoke post <NUM> and the proximal end <NUM> and thus moves the clip <NUM> proximally and distally relative to the capsule <NUM>. As would be understood by those skilled in the art, the shape of the yoke post <NUM> is not important so long as the yoke post <NUM> is strong enough to transmit the desired proximal and distal forces from the control wire <NUM> to the clip <NUM>. Thus, the yoke post <NUM> may be formed in various geometries including, for example, rectangular, round or oval, etc. As would be understood by those skilled in the art, a proximal portion of the yoke <NUM> can be coupled to the clevis <NUM> via a shear pin <NUM> which is designed to fail when subject to a predetermined force, such as a tension exerted thereto via the control wire <NUM>. As shown in <FIG> and <FIG>, the shear pin <NUM> may be formed, for example, as a substantially cylindrical pin extending through openings in the yoke <NUM> and the clevis <NUM> with ends thereof, in one embodiment, having a conical radius aiding in centering the clip <NUM> in the capsule <NUM>. However, any other suitable shapes of the yoke <NUM> may be applied as well. In an alternate embodiment, the shear pin <NUM> may be coupled to one or both of the yoke <NUM> and the clevis <NUM> via an interference fit. The yoke <NUM> may include lateral walls which extend over sides of the clevis so that the shear pin <NUM> may pass on a line through both the yoke <NUM> and the clevis <NUM>, as can be seen in the embodiment of <FIG>. Each lateral wall of the yoke <NUM> may further comprise a centering boss <NUM> formed as a tabbed protrusion projecting radially outward therefrom. The centering boss <NUM> can be formed with a radius consistent with the inner diameter of the capsule <NUM> to center the clip <NUM> therein. A proximal end of the clevis <NUM> can be attached to a distal end of the control wire <NUM>. In this embodiment, the distal end of the control wire includes a ball joint <NUM> which is received in a correspondingly sized and shaped recess of the clevis <NUM>, coupling the clevis <NUM> to the control wire <NUM>. Those skilled in the art will recognize that any number of attachment arrangements may be used to bond the control wire <NUM> to the clevis <NUM> so long as the attachment is capable of transmitting the desired force, such as tension from the control wire <NUM> to the clevis <NUM> and, consequently, to the yoke <NUM> and the clip <NUM>. Thus, actuation of the control wire <NUM> distally and proximally can open and close the clip according as will be described in more detail below.

The clip <NUM> of the present invention may be opened and closed a plurality of times during a procedure so long as a proximal pull force exerted on the control wire <NUM> does not exceed a predetermined threshold which is designed to cause the shear pin <NUM> to fail, thus locking the clip <NUM> closed, as will be described in more detail below. Specifically, a user may open and close the clip <NUM> a plurality of times to properly situate the clip <NUM> over target tissue before locking the clip <NUM> in place. When a desired placement area has been reached, and it is desired to lock the clip <NUM> in place, the user may draw the control wire <NUM> proximally to draw the clip <NUM> into the capsule <NUM>. Alternatively, the capsule <NUM> may be advanced distally to provide the force necessary to draw the clip <NUM> thereinto. The arms <NUM> gradually increase in width from a narrow proximal end to increased width shoulders 104b at a distal end so that, as the clip <NUM> is drawn proximally into the capsule <NUM>, a point is reached at which the clip <NUM> is closed, with distal ends of the arms <NUM> coming together to grip tissue and the shoulders 104b engaging the distal end of the capsule <NUM> to prevent the clip <NUM> from being drawn further into the capsule <NUM>. At this point, an additional pull force exerted on the control wire <NUM> increases the tension on the shear pin <NUM> until a failure level is reached. When this happens, the clevis <NUM> is separated from the yoke <NUM> and the clip <NUM> is locked in the closed configuration over any tissue gripped thereby. The clip <NUM> may employ a locking means known in the art. The shear pin <NUM> is made of a material such as a polymer or a metal such as tantalum, gold or silver, wherein the release force of the material is approximately <NUM> - <NUM> N. Alternatively, the release force may vary from <NUM> - <NUM> N. Thus, the clevis <NUM> and yoke <NUM> can be formed to have a strength greater than that of the shear pin <NUM>. These items may be formed, for example, of Stainless Steel or a high strength polymer or thermoset. The fractured shear pin <NUM> is adapted to remain housed within the capsule <NUM>, wherein a construction thereof ensures that fractured pieces thereof do not include sharp edges. In this manner, smaller fractured portions thereof pose no potential harm to a patient even if they escape the capsule <NUM>.

As described in more detail in the '<NUM> application, as the freed clevis <NUM> is pulled proximally, it engages a distal face of a bushing support <NUM>, driving the bushing support <NUM> proximally into a bushing <NUM> at the distal end of the flexible member <NUM>. When received within the proximal end of the capsule <NUM>, the bushing support <NUM> engages at least one tab (not shown) of the bushing <NUM> urging the tab radially outward into engagement with corresponding windows (not shown) of the capsule <NUM>. The tabs of the bushing are biased toward a radially inward position out of engagement with the windows of the capsule <NUM> so that, when the bushing support <NUM> is dislodged from the proximal end of the capsule <NUM>, the tabs of the bushing <NUM> are freed to disengage the windows of the capsule and the capsule <NUM> is permanently separated from the bushing <NUM> and the flexible member <NUM>, leaving the clip <NUM> locked on the gripped tissue. The flexible member <NUM> may then be withdrawn from the body.

In an alternate embodiment, instead of the bushing support <NUM>, the capsule <NUM> may be maintained in engagement with the bushing <NUM> by a retainer <NUM> formed at the distal end of the bushing <NUM>. The retainer <NUM> may include tabs <NUM> which engage corresponding windows (not shown) in the capsule <NUM> (or, alternatively, by a friction fit). The retainer <NUM> may comprise an opening <NUM> sized to slidably receive the control wire <NUM> therein with a slot <NUM> allowing the retainer <NUM> to be slid in place over the wire <NUM>. The slot <NUM> is sized to allow the retainer <NUM> to be clipped onto the control wire <NUM>, thus obviating the need to thread the control wire <NUM> through the retainer <NUM>. The retainer <NUM> may further comprise two spring arms <NUM>, each of which may include a tab <NUM> biased to engage the corresponding window of the capsule <NUM>. Then, when the shear pin <NUM> fails and the clevis <NUM> is drawn proximally as described above, the clevis <NUM> can drive the retainer <NUM> into the bushing <NUM>, drawing the tabs <NUM> out of engagement with the capsule <NUM> and freeing the capsule <NUM> from the flexible member <NUM> in a manner similar to that described earlier. The flexible member <NUM> may then be withdrawn from the body. In one embodiment, the retainer <NUM> is composed of a metal that can be tempered, such as <NUM>-<NUM> Stainless Steel. However, it is noted that the retainer <NUM> may be made of numerous biocompatible materials including biocompatible metals and formable polymers without deviating from the scope of the present invention.

As shown in <FIG>, a clip <NUM> according to a further embodiment, not forming part of the invention, comprises a relatively hourglass-shaped proximal portion sized to engage a clevis <NUM> in a capsule <NUM> in a manner substantially similar to that described above in regard to the device <NUM>. However, in this embodiment, the yoke and clevis have been replaced by a unitary clevis <NUM> with arms <NUM> of the clevis <NUM> extending around the proximal end of the clip <NUM> so that a shear pin <NUM> received through openings <NUM> of the clevis <NUM> extends into the hourglass-shaped proximal portion of the clip <NUM> in a manner similar to the yoke post <NUM> of the device <NUM>. The clip <NUM> may be coupled to a control wire <NUM> in a manner similar to that described for the device <NUM>. Furthermore, the connection between a flexible member <NUM> and the capsule <NUM> and the mechanism for separating the capsule <NUM> from the flexible member <NUM> may also be substantially similar to that described for the device <NUM>.

The capsule <NUM> may be formed with clip retaining tabs <NUM> at a proximal portion thereof to hold the clip <NUM> in place within the capsule <NUM> after deployment, thus locking the clip <NUM> in the closed configuration. Specifically, during deployment, the clip <NUM> is retracted proximally by a predetermined distance into the capsule <NUM>, drawing the hourglass-shaped proximal portion of the clip <NUM> proximally past a proximal end of the tabs <NUM> and a decreased thickness portion <NUM> of the clip <NUM> distally of the hourglass-shaped proximal portion, adjacent to the tabs <NUM>. This movement permits the tabs <NUM> to spring radially inward so that contact between the proximal ends of the tabs <NUM> and the hourglass-shaped proximal portion of the clip <NUM> locks the clip <NUM> in the capsule <NUM> and prevents the clip <NUM> from re-opening. Furthermore, although a holding force applied by the clip retaining tabs <NUM> is substantial enough to retain the clip <NUM> therein after deployment, it is preferably selected so that a distal force, such as a compression force applied to the control wire <NUM> may move the hourglass-shaped proximal portion distally past the tabs <NUM> enabling a user to reopen the clip (e.g., for repositioning) at any time before the control wire <NUM> is separated from the clevis <NUM>.

As described above, arms <NUM> of the clip <NUM> are provided with shoulders 204b defining an increased thickness portion 204a which prevent the clip <NUM> from being pulled into the capsule <NUM> beyond a predetermined length. Thus, when the clip <NUM> has been drawn into the capsule <NUM> by this distance, additional pulling force applied to the control wire increases a tension thereon until the fail level of the shear pin <NUM> is reached as described above. As shown in <FIG>, the shear pin <NUM> may, for example, be provided with one or more stress concentrators <NUM> formed as grooves formed along the outer diameter thereof, the stress concentrators <NUM> defining a weaker point along the length of the shear pin <NUM>. Those skilled in the art will understand that the size and number of these stress concentrators may be varied to obtain any desired fail level of the shear pin <NUM>.

As shown in <FIG> and <FIG>, a clip <NUM> according to another exemplary embodiment not forming part of the invention can be releasably attached at a proximal end to a shell <NUM>. The shell <NUM> may comprise proximal and distal halves <NUM>, <NUM>, respectively, releasably attached to one another. A proximal end of the proximal half <NUM> can be attached to a control wire <NUM>. The proximal half <NUM> may be formed as two complementary pieces which are assembled over the distal end of the control wire <NUM>. For example, a first one of the pieces of the proximal half <NUM> may include one or more male posts <NUM>, while the other piece includes a corresponding set of female holes <NUM> which aid in aligning the pieces with one another and bonding the pieces together (e.g., via adhesive) to form the proximal half <NUM>. Similarly, the distal half <NUM> may be formed as two pieces which are assembled over the proximal end of the clip <NUM> with a similar set of complementary male posts <NUM> and female holes <NUM> to align the pieces when assembled (e.g., via adhesive) as the distal half <NUM>. Those skilled in the art will understand that the pieces of the proximal and distal halves <NUM>, <NUM>, respectively, may be formed by, for example, injection molding. Specifically, each of the proximal half <NUM> and distal half <NUM> in this embodiment can be formed from a pair of complementary semi-cylindrical pieces, attached to one another using the male posts <NUM> and female holes <NUM> as references. Furthermore, the male posts <NUM> and female holes <NUM> may serve as energy directors for ultrasonic welding, as those skilled in the art will understand.

The clip <NUM> may comprise two arms <NUM>, each comprising a proximal portion extending radially outward and contained within a capsule <NUM>, as shown in <FIG> and <FIG>. It is noted that although exemplary embodiments are disclosed as having two arms, any plurality of arms may be employed without deviating from the scope of the present disclosure. The clip <NUM> is further provided with shoulders (not shown) which prevent the clip <NUM> from being retracted into a capsule <NUM> beyond a predetermined distance as described above in regard to the embodiments of <FIG>. A large cavity <NUM> is formed in the proximal end of the distal half <NUM> while a corresponding cavity <NUM> is formed in the distal end of the proximal half <NUM>. The cavities <NUM>, <NUM> receive proximal ends of the arms <NUM> and constrain them to remain therein against a bias which urges the proximal ends of the arms <NUM> and tabs <NUM> formed thereby radially outward.

Movement of the clip <NUM> is controlled by the control wire <NUM>, which extends through a flexible member <NUM> in the same manner described above out of the body to a proximal portion accessible to a user. A distal end of the control wire <NUM> may include an increased diameter portion such as a sphere or cylinder is received within a correspondingly sized and shaped recess <NUM> at the end of a lumen in the proximal half <NUM> sized to receive the distal portion of the control wire <NUM>. Thus, the proximal half 362can be coupled to the control wire <NUM> for movement proximally and distally therewith. A center post <NUM>, which may extend proximally from a proximal end of the distal half <NUM>, may include an increased diameter portion <NUM> at a proximal end thereof. The proximal end of the post <NUM> may be coupled to side walls of the cavity <NUM> to bind the center post <NUM> to the distal half <NUM>. The increased diameter portion <NUM> may be inserted into the recess <NUM> before the pieces of the proximal half <NUM> are bonded to one another in the same manner as the distal end of the control wire <NUM>. Thus, the post <NUM> can bind the proximal and distal halves <NUM>, <NUM> to one another The recess <NUM> may also be sized to receive the distal end of the control wire <NUM> and the proximal end of the center post <NUM> with a substantial friction fit to prevent unwanted movement of the respective elements therein. Those skilled in the art will recognize that the control wire <NUM> and the post <NUM> may be coupled to the proximal half <NUM> in any number of ways (e.g., with separate recesses <NUM>) including, but not limited to, welding, bonding, melting, etc..

During insertion, the clip <NUM> can be partially retracted into the shell <NUM>, causing the arms <NUM> to approach one another. Upon reaching a target tissue site, a distal compressive force may be applied to a control wire <NUM>, which translates the force to the center post <NUM>, the force being further translated to the distal half <NUM> of the shell <NUM>, thereby pushing the clip <NUM> out of the shell and causing the arms <NUM> to expand radially away from one another. When target tissue is received between the arms <NUM>, the control wire <NUM> can be withdrawn proximally while maintaining the flexible member <NUM> and the capsule <NUM> substantially immobile so that the clip <NUM> is retracted into the shell <NUM> drawing the arms <NUM> toward one another. After the shoulders (not shown) have engaged the capsule <NUM> to prevent further withdrawal of the clip <NUM> thereinto, additional proximally directed force applied to the control wire <NUM> increases tension on the control wire <NUM> and, consequently, on the post <NUM> until a failure level of the post <NUM> is exceeded. In one embodiment, the center post <NUM> is composed of a material similar to that of the shear pin <NUM> formed to fail at approximately <NUM> - <NUM> N, as those skilled in the art will understand. Alternatively, the center post <NUM> may be formed of another suitable material and/or geometry. When the post <NUM> fails, the proximal and distal halves <NUM>, <NUM> can be separated from one another, and the tabs <NUM> which are no longer constrained by the walls of the cavity <NUM> of the proximal half <NUM> can spring outward and engage corresponding features of the capsule <NUM> (e.g., windows <NUM>) to lock the clip closed and keep it in position within the capsule <NUM>.

As shown in <FIG>, a clip <NUM> according to another exemplary embodiment not forming part of the invention may include arms <NUM> residing in a capsule <NUM>. The arms <NUM> bend along a curve to bias the proximal and distal ends thereof radially away from one another in a manner similar to that of the embodiment of <FIG> and <FIG>. C urves of the proximal portions of the arms <NUM> may form a pocket <NUM> while the distal ends of the arms <NUM> are formed in a manner substantially similar to that of the previously described embodiments. Proximal ends of the arms <NUM> may contain openings <NUM> through which a wire loop <NUM> may pass to couple the clip <NUM> to a control wire <NUM>. Those skilled in the art will recognize that the openings <NUM> may be formed as rounded openings with smoothed edges to prevent unwanted trauma to the wire loop <NUM>. In assembly, an end of the wire loop <NUM> can be passed through the openings <NUM> and the two ends of the wire loop <NUM> can be coupled to the distal end of the control wire <NUM> using, for example, a wire mate <NUM> compressed thereover. For example, the wire mate <NUM> may comprise a section of hypotube crushed over the wire loop <NUM>. Alternatively, as would be understood by those skilled in the art, the wire mate <NUM> may be coupled to the wire loop <NUM> and the control wire <NUM> by staking, bonding, welding or any other known method. In the initial configuration, the wire loop <NUM> can be bound with a minimal clearance, thereby gripping the proximal ends of the arms <NUM> tightly against one another against the bias of the arms <NUM> urging the proximal ends of the arms <NUM> radially outward away from one another. In yet another embodiment (not shown), the control wire <NUM> may be formed as a single continuous wire extending from a proximal portion accessible to a user to a distal portion joined to the openings <NUM> with no mating portions at a distal portion thereof.

In the same manner described above, the control wire <NUM> may be manipulated to position the clip <NUM> over a target portion of tissue. As the clip <NUM> is urged distally out of the capsule <NUM>, the bias of the arms <NUM> moves the distal ends thereof away from one another to an open tissue receiving configuration. When the target tissue is received between the distal ends of the arms <NUM>, the control wire <NUM> may be drawn proximally to retract the clip <NUM> into the capsule <NUM> bringing the distal ends of the arms <NUM> together to grip the tissue therebetween. As the clip <NUM> enters the capsule <NUM>, shoulders (not shown) of the arms <NUM> may contact the capsule <NUM> preventing further entry of the clip <NUM> into the capsule <NUM>. Additional proximally directed force applied to the control wire <NUM> after this point increases tension in the control wire <NUM> until the wire loop <NUM> fails, releasing the proximal ends of the arms <NUM> to spring radially outward away from one another allowing tabs <NUM> to engage windows <NUM> of the capsule <NUM>, locking the clip <NUM> closed and maintaining the clip <NUM> in the capsule <NUM>. The wire mate <NUM> now moves proximally to disengage the capsule <NUM> from a flexible member (not shown) using a mechanism similar to any of those described in the previous embodiments.

As shown in <FIG>, any of the above embodiments may include a locking mechanism which will lock the control wire and any components coupled to the distal end thereof within the distal end of a bushing or flexible member as described above. This should prevent a user from moving the severed control wire distally out of the distal end of the flexible member or bushing after the clip has been deployed to safeguard against injuries that may be caused by contact with the control wire or any components (e.g., proximal half <NUM>) attached thereto.

Specifically, a closeable or crushable wire lock <NUM> is disclosed which may provide a streamlined system to more safely remove these components from the body. The closeable wire lock <NUM> is intended to prevent pushing the sharp, sheared control wire into the anatomy for safety reasons. The closeable wire lock <NUM> may be used to forcibly separate the capsule <NUM> from a bushing <NUM> attached to a flexible member <NUM>, the bushing <NUM> adapted to be separatable from the capsule <NUM> via a retainer or other mechanism as disclosed with reference to <FIG>. Specifically, the closeable wire lock <NUM> may be particularly useful in cases where all other frangible links between the capsule <NUM> and bushing <NUM> have been broken. Furthermore, the closeable wire lock <NUM> may be employed in any of the clip deployment mechanisms disclosed herein.

With reference to <FIG>, a closeable wire lock <NUM> can be formed as a tube slidably receiving therein a control wire <NUM>. A closeable section of the lock <NUM> may include a series of hubs <NUM> coupled to one another by a series of struts <NUM> and separated from one another by a series of openings <NUM>. It is noted that although the present embodiment is disclosed with three hubs <NUM> and four struts <NUM>, any number of hubs <NUM> and struts <NUM> may be employed herein without deviating from the scope of the present disclosure. As in the embodiments described above, a control wire <NUM> may extend through the lock <NUM> to a distal end comprising, for example, a ball and socket joint within a bushing <NUM>. When the control wire <NUM> is separated from the clip and moves proximally through the capsule, the ball <NUM> is adapted to enter an enlarged distal end <NUM> of the lock <NUM> formed, for example, as a series of fins <NUM> separated from one another and bent slightly radially outward. As the ball <NUM> moves proximally into the end <NUM> of the lock <NUM>, the fins <NUM> can grip the ball <NUM> preventing relative movement between the control wire <NUM> and the lock <NUM>. Further proximally directed force applied to the control wire <NUM> should draw the ball <NUM> pushes the lock <NUM> proximally. A proximal end (not shown) of the lock <NUM> can be immovably coupled to the flexible member <NUM> so that this proximally directed force applied to the control wire <NUM> compresses the lock <NUM> causing the struts <NUM> to bend radially outward moving the hubs <NUM> toward one another as the openings <NUM> are closed. When bent outward, the struts <NUM> engage spaces between the coils of the flexible member <NUM> preventing relative movement between the lock <NUM> and the flexible member <NUM>. Thus, the control wire <NUM> can be locked within the distal end of the flexible member <NUM> and can not be advanced distally therefrom to cause injury.

Claim 1:
A tissue clipping apparatus, comprising:
a flexible, elongate member (<NUM>), a proximal end of which remains external to the body accessible to a user while a distal end of the flexible member is inserted into the body to a location adjacent to target tissue to be clipped;
a control wire (<NUM>) extending through the flexible member;
a capsule (<NUM>) releasably coupled to a distal end of the flexible member; and
a clip (<NUM>),
a proximal portion of which is received within the capsule;
wherein a distal end of the flexible member comprises a bushing (<NUM>) releasably coupled to the capsule wherein the capsule is maintained in engagement with the bushing by a retainer (<NUM>),
characterised in that the retainer engages the capsule by a friction fit.