Through the scope tension member release clip

A hemostatic clip assembly for mounting on a delivery device comprises a capsule and a clip slidably mounted within the capsule so that, when the clip is drawn proximally into the capsule, arms of the clip are drawn together to a closed position, an abutting surface of at least one of the arms contacting a corresponding surface of the capsule when the clip is drawn to a predetermined position within the capsule to provide a first user feedback indicating closure of the clip in combination with a tension member connected to the clip arms and biasing the clip arms toward an open, tissue receiving configuration and a yoke slidably received within the capsule and releasably coupled to the tension member, the yoke including a ball cavity for receiving a ball connector of a control element of the delivery device to maintain the clip assembly coupled to the delivery device, wherein the control element is frangible to detach the yoke from the delivery device and to provide a second user feedback and, wherein release of the yoke from the tension member provides a third user feedback.

BACKGROUND

Endoscopic procedures to treat pathologies of the gastro-intestinal (“GI”) system, the biliary tree, the vascular system and of other body lumens are becoming increasingly common.

Hemostatic clipping tools have been inserted through endoscopes to deploy hemostatic clips which stop internal bleeding by clamping together the edges of a wound. Such a clipping tool, complete with clips attached to a distal end thereof, may be inserted through an endoscope to the location of bleeding. A clip is then remotely manipulated into position over the site of the bleeding, clamped over the wound and detached from the tool.

One challenge facing the endoscope operator is to properly position the hemostatic clips over the wound to effectively stop the bleeding. If a clip is deployed improperly, additional clips may be required to stop the bleeding, extending the time required for and the complexity of the procedure and leaving additional medical devices within the patient. It is also important for the device operator to be certain of the status of deployed clips during the deployment operation. For example, before withdrawing the tool from the endoscope, the operator should have positive indication that all of the deployed clips have been fully deployed and completely released from the tool to prevent a clip which is clamped on tissue yet cannot be released from the tool.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a hemostatic clip assembly for mounting on a delivery device comprising a capsule and a clip slidably mounted within the capsule so that, when the clip is drawn proximally into the capsule, arms of the clip are drawn together to a closed position, an abutting surface of at least one of the arms contacting a corresponding surface of the capsule when the clip is drawn to a predetermined position within the capsule to provide a first user feedback indicating closure of the clip in combination with a tension member connected to the clip arms and biasing the clip arms toward an open, tissue receiving configuration and a yoke slidably received within the capsule and releasably coupled to the tension member, the yoke including a ball cavity for receiving a ball connector of a control element of the delivery device to maintain the clip assembly coupled to the delivery device, wherein the control element is frangible to detach the yoke from the delivery device and to provide a second user feedback and, wherein release of the yoke from the tension member provides a third user feedback.

DETAILED DESCRIPTION

Hemostatic clips are used routinely to stop bleeding from openings created during surgery as well as wounds resulting from other trauma to tissues. In the simplest form, these clips grasp the tissue surrounding a wound and bring the wound's edges together to allow natural processes to heal the wound. Endoscopic hemostatic clips are used to stop internal bleeding resulting from surgical procedures and/or tissue damage from disease, etc. Specialized endoscopic hemostatic clipping devices are used to bring the clips to the desired location within a patient's body and to position and deploy the clip at the appropriate place on the tissue. The clipping device is then withdrawn, leaving the clip within the patient.

Endoscopic hemostatic clipping devices are designed to reach affected tissues deep within a patient's body, such as within the GI tract, the pulmonary system, the vascular system or within other lumens and ducts. During the procedures to treat those areas, an endoscope is generally used to provide access to and visualization of the tissue which is to be treated. The clipping device may, for example, be introduced through a working lumen of the endoscope. The design and construction of such a “through the scope” endoscopic hemostatic clipping device presents several challenges. The endoscopic clipping device has to be sufficiently small to fit in the lumen of an endoscope and, at the same time, must be designed to provide for the positive placement and actuation of the hemostatic clip. Feedback to the operator is preferably also provided so that the operator will not be confused as to whether the hemostatic clip has been properly locked in place on the tissue and released from the device before the device itself is withdrawn through the endoscope.

FIG. 1shows a side elevation view of a through the scope hemostatic clipping device according to an exemplary embodiment of the present invention. This device is a hand operated tool that is used to insert a hemostatic clip through an endoscope lumen, position the clip over a wound, clamp it and deploy it over the affected tissue. The tool is further designed to release the hemostatic clip once it has been clamped in place, and to be withdrawn through the endoscope. To more clearly explain the operation and construction of the exemplary device, it may be divided into three principal components. As shown, the hemostatic clipping device100comprises a handle assembly102, a shaft section104, and a clip assembly106. The clip assembly106is shown more clearly inFIG. 1A.

The handle assembly102forms the component that supplies a mechanical actuation force to deploy and clamp the clip. In this embodiment, the device100is hand operated (i.e., the user's hands provide the force required to carry out all the functions related to the hemostatic clip). The handle assembly102may be constructed in a manner similar to conventional handle assemblies of the type generally employed in endoscopic biopsy devices or in similar applications. The handle assembly102allows the user to move a control wire118or other force transmission member, which extends through the shaft section104to the clip assembly106at a distal end of the device100. The handle assembly102comprises a handle body108which can be grasped by the user to stabilize the device and apply a force to it. A sliding spool110is connected to control wire118, so that the user can easily pull or push said wire118as desired.

As shown inFIGS. 1 and 2, a sliding spool110is mounted on the handle body108so that it can slide along a slot116, which maintains its position within the handle assembly102. Because the sliding spool110is connected to the control wire118, the user may manipulate the control wire118by grasping the handle body108and moving the sliding spool110along the slot116. A return spring112may be provided within the handle body108to bias the sliding spool110, and thus the control wire118toward a desired position. In the present embodiment, the sliding spool110is biased to the proximal position. The handle assembly102may also include a connection portion114, which receives the control wire118and attaches the shaft section104to the handle assembly102.

The shaft section104mechanically connects the handle assembly102to the clip assembly106and, together with the clip assembly106, is designed to be inserted into a lumen of an endoscope. As shown inFIGS. 3 and 4, the shaft section104comprises an outer flexible coil130which is designed to transmit a torque from the proximal end to the distal end of the device100and to provide structural strength to the shaft section104. The coil130may be a conventional coil used in biopsy devices and may, for example, comprise a single, coiled wire. The coiled wire may have a round, square or a rectangular cross section, and may be made of a biocompatible material such as, for example, stainless steel. Additional protective and low friction outer layers may be included on the shaft section104, according to known methods of construction.

The control wire118transmits mechanical force applied to the handle102to the clip assembly106. The control wire118has a proximal end which is attached to a movable part of the handle102, such as the sliding spool110, using known methods. Stainless steel or other high yield biocompatible materials may be used to manufacture the control wire118, so that the structural integrity of the assembly is maintained. It is also important to prevent stretching of the control wire118when under tension since, if the wire stretches, the handle102will have to travel a greater distance to carry out a desired operation. As shown inFIG. 5, the distal end of the control wire118ends in a ball140which is used to connect the control wire118to the appropriate elements of the clip assembly106, as will be described below. In this embodiment, the diameter of the control wire118is substantially constant from a proximal end thereof to a proximal end of a distal tapered section144. The ball140may have a diameter which is greater than the diameter of the control wire118, to facilitate attachment to a yoke204. The control wire118may extend the length of the device100, from the yoke204to the sliding spool110, and slides longitudinally through the device100. It may be made, for example, of stainless steel or other biocompatible metal.

The control wire118may also include a reduced diameter section142designed to fail when a predetermined tension is applied thereto through the handle assembly102. The tapered section144may be used to transition between the main body of the control wire118and the reduced diameter section142, without steps or other discontinuities which may concentrate stress and make the fracture point more unpredictable. As will be described in greater detail below, one purpose of the reduced diameter section142is to facilitate the release of a hemostatic clip from the hemostatic clipping device100once the clip has been properly deployed. It will be apparent to those of skill in the art that the location of the reduced diameter section142along the control wire118may be varied to take into account specific requirements of the device100.

An inner sheath132may be used in the construction of the shaft section104, as shown inFIGS. 3 and 4. The inner sheath132provides a low friction bearing surface disposed between the outer diameter of the control wire118, and the inner diameter of the shaft section104. The inner sheath132may be formed of a low friction material such as, for example, Teflon™, HDPE or Polypropylene. In one exemplary embodiment, the inner sheath132is slidable within the shaft section104, and the control wire118is slidable within the inner sheath132forming a low friction system of multiple bearing surfaces. To further reduce friction, a bio-compatible lubricant may be applied to the inner and outer surfaces of the inner sheath132, along the length of the shaft section104. For example, silicone lubricants may be used for this purpose.

A slidable over-sheath150may be included in the design of the shaft section104, as shown inFIGS. 1 and 2. The over-sheath150is designed to protect the inner lumen of the endoscope from the metal clip assembly106and from the metal coil130while the hemostatic clipping device100passes through the endoscope's lumen. After the clipping device100and, more specifically, after the clip assembly106has passed through the endoscope, the over-sheath150may be withdrawn to expose the distal portion of the clipping device100. The over-sheath150may be formed, for example, as a single lumen plastic extrusion element slidable over the distal portions of the clipping device100to selectively cover and uncover the clip assembly106. In one embodiment, the over-sheath150is formed of a low friction polymer such as, for example, Teflon™, HDPE, Polypropylene, or similar materials.

The over-sheath150may include a grip portion152and an elongated body154. The grip portion152is designed as a handle making it easier for the user to slide the over-sheath150over the shaft of the clipping device100. In one exemplary embodiment, the grip portion152is made of a rubber-like material to provide a good gripping surface for the user. For example, an injection moldable polymer such as TPE may be used to construct the grip portion152. The elongated body154may be formed as a substantially cylindrical shell surrounding the shaft of the clipping device100. The elongated body154may be attached to the grip portion152using conventional methods as would be understood by those skilled in the art.

As shown inFIGS. 6 and 7, an exemplary grip portion152comprises a central hollow channel160that may be used to receive the shaft of the clipping device100. The central hollow channel160is aligned with the elongated body154to provide a continuous channel containing the shaft of the clipping device100. The material of the grip portion152may have a high coefficient of friction, so that an interference fit is possible between the central hollow channel160and the shaft of the clipping device100without the use of adhesives or mechanical fastening devices. In one embodiment, friction bosses158may be provided on an inner diameter of the hollow channel160to provide additional friction between the shaft of the clipping device100and the over-sheath150assembly. The friction bosses158may be formed, for example, as protrusions extending from the inner diameter of the over-sheath150and may have a variety of stubby or elongated shapes. The amount of friction between these two components may be balanced so that no unwanted relative movement takes place while, at the same time, making it relatively easy for the user to slide the over-sheath150proximally and distally when necessary.

A sheath stop156may be provided for the clipping device100to prevent the over-sheath150from sliding away from the distal end while the clipping device100is inserted in the endoscope. As shown in the exemplary embodiment ofFIGS. 2 and 8, the sheath stop156physically blocks the grip portion152from sliding proximally to prevent the over-sheath150from being withdrawn and exposing the clip assembly106. The sheath stop156is designed to easily snap in place near the proximal end of the shaft section104where it can be reached and manipulated by the operator during the surgical procedure. Once the clip assembly106has been inserted in the endoscope and has reached the desired location in the patient's body, the sheath stop156may be removed from the shaft section104so that the user can move the grip portion152proximally to uncover the clip assembly106.

The connection between the sheath stop156and the shaft section104may include, for example, pairs of opposing fingers162,164that are designed to snap over the shaft section104. The fingers162,164cooperate to securely and releasably hold the body of the shaft section104therebetween. The fingers162,164respectively comprise guide portions170,172; shaft channel portions166,168; and blocking portions174,176. Insertion of the sheath stop156on the elongated body154is accomplished by pressing the body of the shaft section104between the guide portions170,172, to spread the fingers162,164and allow further insertion of the shaft104between the fingers162,164. The guide portions170,172and the blocking portions174,176are shaped so that insertion of the shaft section104towards the channel portions166,168requires less effort than moving the shaft section104in the opposite direction.

Once the shaft section104has been placed within the channel portions166,168, the fingers162,164snap back to their non-spread position and retain the shaft section104in place therebetween. The shaft section104is removed by pulling the sheath stop156away from the shaft section104. Due to the shape of the blocking portions174,176, removing the shaft section104requires the application of more force than does insertion thereinto. Stops180may also be provided on the sheath stop156to limit the movement of the shaft section104towards the grasping portion161to prevent damage to the device that may be caused by excessive spreading of the fingers162,164. The sheath stop156may be formed of a resilient material, such as a polymer, and may be manufactured by injection molding.

The clip assembly106is disposed at the distal end of the clipping device100, and contains the mechanism that converts the proximal and distal movement of the control wire118into the actions necessary to deploy and release a hemostatic clip90.FIGS. 9,10and11show, respectively, side, top and perspective views of the distal end of the clipping device100, including the clip assembly106having clips in the folded configuration. This configuration is used, for example, to ship the clipping device100and to insert the clipping device100through the lumen of an endoscope. Some of the components of the clip assembly106include a capsule200which provides a structural shell for the clip assembly106, the clip arms208which move between open and closed positions, a bushing202attached to the coil130, and a yoke204connecting the control wire ball140and the tension member206.

As depicted in the exemplary embodiment, the proximal end of the capsule200slides over the distal end of the bushing202. A locking arrangement between these two exemplary components is provided by capsule tabs212, which are designed to lock into the bushing202so that mechanical integrity is temporarily maintained between the capsule200and the bushing202. Within the capsule200are contained a yoke204and a tension member206which transmit forces applied by the control wire118to the clip arms208. The ball140formed at the distal end of the control wire118is mated to a receiving socket210formed at the proximal end of the yoke204. A male C-section214extending from the tension member206is received in a corresponding female C-section216formed in the yoke204, so that the two components are releasably connected to one another, as will be described below. The clip arms208in the closed configuration have a radius section300which is partially contained within the capsule200to prevent opening of the arms. Each of the clip arms208goes over the tension member206and has a proximal end252which slips under a yoke overhang254, to further control movement of the arms208.

FIGS. 12 and 13show a top and a perspective view of one exemplary embodiment of the clip assembly106in an open configuration, with the clip arms208in a fully open position. The open configuration is obtained when the sliding spool110shown inFIG. 1is moved distally so that the ball140of the control wire118pushes the assembly containing the yoke204and the tension member206distally within the capsule200. As will be described below, the distal ends of the clip arms208are biased toward the open position and revert to this position whenever they are not constrained by the capsule200. In the exemplary embodiment, a maximum opening of the clip arms208occurs when the clip arms208ride over the folded distal folding tabs220which extend from the distal end of the capsule200, as shown inFIGS. 14 and 15. In this embodiment, the tabs220provide a cam surface, and the clip arms208act as cam followers, being deflected by the tabs220. In addition, the folding tabs220may also provide a distal stop for the tension member206, to retain it within the capsule200. Thus, by moving the sliding spool110distally, the user opens the clip arms208to prepare to grasp tissue therebetween.

When the sliding spool110is moved proximally by the user, the assembly within the capsule200also moves proximally and the clip arms208are withdrawn within the capsule200. As the clip arms208move proximally within the capsule200, clip stop shoulders (CSS)222contact a distal portion of the capsule200, for example, the folded tabs220. This interaction of the CSS222with the capsule200provides to the user a first tactile feedback in the form of increased resistance to movement of the sliding spool110. This feedback gives to the operator a positive indication that further movement of the handle control will cause the hemostatic clip90to be deployed from the clip assembly106. The operator may then decide whether the current position of the clip90is acceptable or not. If the position is acceptable, the operator can fully deploy the clip90by continuing to move the sliding spool110with increased proximal pressure to separate the yoke204from the tension member206. If not, the operator can move the sliding spool110distally to re-open the clip arms208and extend them out of the capsule200, reposition the clip90, and repeat the above steps to close the clip90at a more appropriate location.

When the user determines that the clipping device100is positioned correctly, the proximal pressure on the sliding spool110may be increased to continue deployment of the hemostatic clip90from the clip assembly106.FIGS. 16 and 17show respectively a top and side view of the clipping device100in this condition. As the proximal tension on sliding spool110is increased, the control cable118pulls the yoke204proximally, away from the tension member206. The tension member206is firmly attached to the clip arms208which are prevented from moving proximally by the interaction of the CSS222with the folded tabs220. If sufficient pulling force is applied to the yoke204, the male C section214of the tension member206yields and loses integrity with the female C section216of the yoke204. This can occur because, in the exemplary embodiment, the tension member206is formed of a material with a lower yield strength than the material of the yoke204.

The force required to break the tension member206away from the yoke204may be tailored to achieve a desired feedback that can be perceived by the user. The minimum force required to break the tension member206free of the yoke204may be selected so that a tactile feedback is felt by the user, to prevent premature deployment of the hemostatic clip90while a maximum force may be selected so that other components of the linkage between the sliding spool110and the clip arms208do not fail before the male C section214and the female C section216disconnect from one another. In one exemplary embodiment, the tension force necessary to disconnect the two components may be in the range of approximately 4 lbf to about 12 lbf. This range may vary depending on the size of the device and the specific application. To obtain this force at the interface of the male and female C sections214,216a larger force will be applied by the user at the sliding spool110, since friction within the device may cause losses along the long flexible shaft.

When the male C section214of tension member206yields, several events take place within the exemplary device100nearly simultaneously. More specifically, the yoke204is no longer constrained from moving proximally by the CSS222abutting the capsule200. Thus the yoke204travels proximally until coming to rest against a distal bushing shoulder250. The tension member206is not affected by this movement since it is no longer connected to the yoke204. The proximal ends252of the clip arms208are normally biased away from a center line of the device100and are no longer constrained by the yoke overhangs254. Accordingly, the clip latches302are free to engage the latch windows304of the capsule200, thus maintaining the integrity of the capsule-clip arms combination after deployment. Details of one exemplary embodiment of the capsule200are shown in FIGS.14,15and details of the clip arms208are shown inFIGS. 18,19and20.

As the yoke204moves proximally to abut against the bushing202, the capsule tabs306are bent away from the centerline of the capsule200by the cam surfaces of the yoke204. As a result, the capsule tabs306no longer engage the corresponding bushing undercuts350, shown in the side and perspective views of the bushing202depicted inFIGS. 21,22. Since the capsule200and the bushing202(which is securely connected to shaft section104) are no longer connected, the clip assembly106is prevented from being released from the shaft section104only by its connection to the ball140of the control wire118. As will be described in greater detail below, in different exemplary embodiments of the capsule, the capsule tabs306may be replaced by different structures.

A further result of moving the yoke204against the distal bushing shoulder250of the bushing202is that the distal end of the wire stop360(shown in FIGS.12,16) is placed near the proximal bushing shoulder364(shown inFIG. 22). The flared fingers362located at the distal end of the wire stop360, better shown inFIG. 23, are compressed as they pass through the central ID of the bushing202, but return to their normally biased open position (shown inFIG. 23) after passing past the proximal bushing shoulder364. Further distal movement of the sliding spool110is thus prevented since that movement would engage the fingers362of the wire stop360with the proximal bushing shoulder364. This feature prevents the clip assembly106from being pushed away from the bushing202before the ball140is separated from the control wire118, as will be described below.

The wire stop360comprises a tube with a first slotted and flared end attached to the control wire118by conventional means. As shown inFIG. 23, the slots impart flexibility to the device so it can easily pass through the central lumen of the bushing202. Flared fingers362are formed by the slots, and engage the proximal bushing shoulder364. The wire stop360is made of a material that is biocompatible and that has enough resilience so that the fingers362re-open after passage through the bushing202. For example, stainless steel may be used for this application. In different exemplary embodiments that will be described in greater detail below, the wire stop360may be omitted from the device.

One feature of the exemplary embodiment of the invention described above is that the user receives both tactile and auditory feedback as the clip assembly106is deployed and released. The separation of the tension member206from the yoke204produces a small clicking noise and a tactile feel that is perceptible while holding the handle assembly102. The change in axial position of the sliding spool110is thus augmented by the changes in resistance to its movement and by the clicking sound and feel through the start and stop of the movement. As a result the user is always aware of the status of the clip assembly106, and the inadvertent deployment of a hemostatic clip90in an incorrect location is made less likely. It will be apparent to those of skill in the art that the order of male and female connectors in the device may be reversed or changed without affecting the operation of the device.

It may be beneficial for the user to be certain that the clip assembly106has been deployed before the rest of the clipping device100is removed from the endoscope. Injury to the tissue being treated could result if the clipping device100is removed from the operative site when the hemostatic clip90is only partially deployed. Accordingly, a large tactile feedback may be incorporated, to augment the auditory and tactile feedback stemming from the separation of the yoke204from the tension member206.FIG. 24depicts the condition where the clip assembly106separates from the rest of the clipping device100. According to the described embodiment, this second user feedback is obtained by designing the control wire118so that it will separate from the end ball140when a predetermined tension is applied to it. In other words, the ball140of the control wire118is mechanically programmed to yield and separate from the body of the control wire118when a pre-set tension is applied thereto. The size of the reduced diameter section142can be selected so that, when the user continues to move the sliding spool110proximally as the programmed yield tension is reached, the ball140detaches from the tapered section144and provides a large tactile feedback to the operator.

When the ball140detaches, the sliding spool110bottoms out at the proximal end of the handle108, such that a full stroke of the handle assembly102is reached. The tension required to cause the reduced diameter section142to yield and release the ball140may vary over a range of values. However, for best results the force should be greater than the tension force required for the male C section member214to separate from the yoke204. If this condition is not satisfied, a situation may occur where the clip assembly106is locked in place on the patient's tissue, but cannot be released from the clipping device100. It will be apparent that this situation should be avoided. In one exemplary embodiment, the tension force required to separate the ball140from the body of the control wire118is in the range of between about10lbf and20lbf at the distal end of the control wire118. As discussed above, losses along the elongated flexible shaft may require the user to apply a force substantially greater than this to the handle body102.

Once the ball140has separated from the rest of the control wire118, the user can pull the rest of the clipping device100from the endoscope. As this is done, the yoke204is retained within the capsule200by the spring and frictional forces of various features of the capsule200, such as, for example, the capsule tabs306. Prior to withdrawing the clipping device100, the over-sheath150may be moved distally by the user over the entire remaining portions of the shaft section104to prevent damage to the endoscope as the clipping device100is withdrawn therethrough. The sheath stop156may also be placed on the shaft section104proximally of the over-sheath grip152to prevent inadvertent sliding of the over-sheath150from the distal end of the device100.

A more detailed description of several components of the clipping device100follows. The clip arms208are shown in detail inFIGS. 18,19and20; the tension member206is shown in side and top views inFIGS. 25,26; while top and side views of the yoke204are shown respectively inFIGS. 27 and 28the clip arms208may be formed of a biocompatible material such as Nitinol, Titanium or stainless steel. Maximum spring properties may be obtained by using materials such as400series stainless or 17-7 PH. As shown, a tear drop keyway400is formed in the clip arm208to mate with a corresponding tear drop key402formed on the tension member206. This feature maintains the relative positions of these two components and of the yoke204substantially constant. The shape of the keyways400may be varied. For example, the keyway400may be oval or elliptical. Central portions of the clip arms208define a spring section404. When the proximal ends252of the clip arms208are under the yoke204overhangs254, the clip arms208are allowed to pivot over the tension member206, which in turn biases the distal ends252towards the open configuration when no longer restrained by the capsule200. As a result, the proximal end252of each clip arm208springs upward and engages the latch windows304in the capsule200.

The clip arms208also comprise a radius section300that adds strength to the clip and reduces system friction. The radius of the radius section300approximately matches the inner diameter of the capsule200and has a smooth profile to avoid scratching the inner surface of the capsule200. A pre-load angle α is defined between the radius section300and the spring section404. The pre-load angle α a determines how much interference (pre-load) exists between the two opposing clip arms208at their distal ends when closed. The greater the pre-load angle α , the greater the engaging force that is applied by the clip arms208. However, this condition also causes the greatest system friction when the hemostatic clip90is closed. The clip arms208also comprise interlocking teeth408disposed at their distal ends. In the exemplary embodiment, the teeth408are identical so that the arms may be interchangeable and will mesh smoothly with the set facing them. The teeth408are disposed at a nose angle β which may be between approximately 90 and 135 degrees, but in other applications may be greater or lesser than the described range.

One exemplary embodiment of the capsule200is shown in detail inFIGS. 14 and 15. The device comprises alignment keyways500that are designed to mate with corresponding features on the bushing202to rotationally align the two components. In this exemplary embodiment, the capsule tabs306may be bent towards the centerline of the capsule200to engage the bushing undercuts350. The engagement maintains the integrity between the capsule assembly200and the rest of the clipping device100until the yoke204is pulled into the distal bushing shoulder the capsule overhangs502provide added clamping strength to the deployed clip arms208. This is achieved by reducing the length of the portion of each clip arm208that is not supported by a portion of the capsule200. This feature does not affect the amount of tissue that may be captured by the clip arms208since the capsule overhangs502extend on a plane substantially parallel to the plane of the clip arms208.

Additional features of the capsule200include an assembly aid port which may be used to assist in aligning the components of the clip assembly106. Bending aids506facilitate a smooth bend when the distal folding tabs220are bent inward, as described above. The bending aids506, as shown, are holes aligned with the folding line of the tabs220, but may also include a crease, a linear indentation, or other type of stress concentrator. The capsule200may be formed from any of a variety of biocompatible materials. For example, stainless steel, Titanium or Nitinol or any combination thereof may be used. High strength polymers like PEEK™ or Ultem™ may also be used to form the capsule200, with a heat set treatment being used to adjust positionable elements.

A different exemplary embodiment of the present invention is shown inFIGS. 30-33. In this embodiment, several features of the clip capsule and of the control wire actuation mechanism are modified to further facilitate the release of the clips from the delivery mechanism. As indicated above, it is important to ensure that the clip completely separates from the control wire after deployment to prevent a situation where the clip is clamped to the patient's tissue, but cannot be released from the deployment mechanism. Accordingly, the exemplary embodiment shown inFIGS. 30-33incorporates design features which reduce mechanical side loads between the clip capsule and the bushing, and facilitate a smoother and more certain disengagement of the clip.

More specifically, the present exemplary embodiment incorporates an interface portion816of the clip capsule804that is axially shorter than this portion in the above-described embodiments. For example, the interface portion816may up to 60% shorter in this embodiment than in the above-described embodiments. The interface portion816is adapted to releasably connect with the bushing806to temporarily provide structural strength to the assembly. The exemplary embodiment also incorporates a different distal end of the control wire810, which can be used to help separate the clip802and capsule804from the bushing806.

FIGS. 34-37show in greater detail the capsule804according to the exemplary embodiment also shown inFIGS. 30-33.FIGS. 38 and 39show the corresponding bushing806, which is adapted to cooperate with the capsule804to provide a smoother separation of the clip802from the delivery mechanism. Several features of the present exemplary capsule804are similar to features of the embodiments described above and carry out the same functions. For example, the key ways820are designed to cooperate with features822of the bushing806to rotationally align the two components. The latch windows824also perform the same function as described above with respect to other embodiments and cooperate with proximal ends of the clips802.

One feature of the present embodiment is a shortened interface portion816which comprises a different releasable locking mechanism to connect the capsule804to the bushing806. In this embodiment, an “A” frame tab830is designed to cooperate with bushing hooks832to temporarily maintain the capsule804and the bushing806attached to one another.FIGS. 40-43show additional views of the capsule804while it is connected to the bushing806. During assembly of the delivery device, the two components are attached by moving the capsule804over the bushing806and then bending the “A” frame tabs830into the bushing hooks832. The inside distal edge834of each “A” frame tab830is pushed down when joining the two components and locks behind the bushing hooks832.

As a clip802is deployed to clamp tissue and is then released from the deployment device800, the “A” frame tabs830disengage from the hooks832of the bushing806after the tension member814has been broken and the cam surfaces of the yoke engage the “A” frame tabs830as described above. The release sequence is accomplished through movement of the internal components within the capsule804in response to movement of the sliding spool110and the handle108(FIG. 2), as described above with reference to the previous exemplary embodiments of the device.

A second feature included in this embodiment of the clip delivery device800comprises a control wire810and a hypo tube900, as shown inFIGS. 30-33. In the present exemplary embodiment, no wire stop is included and the control wire810may be used to push the clip802away from the clip delivery device800after deployment of the clip802therefrom. This additional function of the control wire810may be utilized after the control wire ball902has separated from the control wire810, for example by programmed failure of the reduced diameter section904. Using the control wire810to push the deployed clip802provides additional assurance that, when the clip802is clamped to the patient's tissue, it will be completely released from the clip delivery device800.

According to the exemplary embodiment shown herein, after failure of the tension member814and before the control wire810is severed, if a user pushes the control wire810distally in an attempt to re-open the clip802, the clip802will remain coupled to the tissue while bound to the control wire810. At this point, due to the shorter longitudinal length of the clip capsule804, the yoke812may be drawn out of the proximal end of the capsule804by proximal movement of the control wire810. The bushing806may then be moved distally as the yoke812is drawn proximally to draw the proximal tapered end of the yoke812into the distal opening in the bushing806. The proximal tapered end of the yoke812allows the yoke812to be realigned with the bushing806as the yoke may have rotated about the control wire ball902. After the yoke812has been re-aligned with the bushing806, the control wire810may be drawn further proximally to separate the control wire ball902from the proximal portion of the control wire810to completely release the clip802.

One mode of operation of the exemplary embodiment of the clip release device800is described with reference toFIGS. 30-33, and also referring back toFIGS. 1 and 2. After the reduced diameter section904has yielded and the control wire810has been separated from the control wire ball902, the sliding spool110is advanced distally by the user relative to the handle108so that the distal (separated) end of the control wire810pushes the clip802distally away from the clip delivery device800, providing a further assurance that the clip802has completely separated from the delivery device800. The user may then safely remove the delivery device800.

After the reduced diameter section904has yielded, the distal end of the control wire810may be jagged or sharp. To limit the possibility of injury from the sharp end of the control wire810, a protective shroud, e.g., the hypo tube900, is placed around the distal portion of the control wire810. For example, the hypo tube900may be crimped onto the control wire810, causing both to move together longitudinally in and out of the catheter. It will be apparent to those of skill in the art that other methods of attaching the hypo tube900to the control wire810may be used without departing from the scope of the invention. The hypo tube900placed around the sharp end of control wire810acts as a blunt surface to minimize trauma to tissue against which the control wire810may be pushed. In addition, the hypo tube90stiffens the reduced diameter section of the control wire810to aid the reduced diameter section in resisting buckling when subjected to compression as the control wire810is moved distally.

In the present exemplary embodiment, the control wire810is free to move longitudinally along the clip delivery device800. Accordingly, various internal passages of the delivery device800are sized to prevent interference with the movement of the control wire810. For example, an inner diameter of the bushing shoulders906may be such that the hypo tube900can pass therethrough without catching the lip of the bushing shoulders906. This feature further facilitates longitudinal movement of the control wire810and its use to push deployed clips802longitudinally away from the deployment device800.

The exemplary embodiment of the clip delivery device800described above thus promotes a more positive and smooth separation of the clip802after it has clamped on the target tissue and before the delivery device800is withdrawn from the patient's body. A clip capsule804having a shorter longitudinal length and “A” frame locking tabs may promote a smoother separation of the capsule804from the bushing806, by reducing the side loads that may exist during deployment and using the control wire810to push the clip802out of delivery device after clamping to the target tissue provides a further assurance of positive release.

FIGS. 25 and 26depict additional details of the tension member206. As shown, tear drop keys402are designed to engage the tear drop keyways400of the clip arms208, as described above. Clip follower planes508are shaped to form a fulcrum which allows the clip arms208to rock between the open and closed configurations. The tension member206comprises a distal stop face510which abuts the distal folding tabs220of the capsule200to stop the distal motion of the capsule assembly106. In general, all surfaces and edges of the tension member206that are in contact with the inner surfaces of the capsule200preferably have a radius substantially similar to an inner radius of the capsule200to provide a sliding fit therein. The tension member206may be formed of a biocompatible polymer, monomer or thermoset. The type of mechanism selected to release the tension member206from the yoke204may determine the type of material used since a release due to fracture of the male C section214requires a relatively brittle material while release due to yielding without fracture calls for a softer material.

Additional details of the yoke204are shown inFIGS. 27-29. When the control wire118is seated in the yoke204, it is desirable to ensure that it cannot inadvertently be removed from the control wire slot600. Accordingly, in the present embodiment the ball cavity602has a diameter sufficiently large to allow the ball140to pass therethrough while the wire cavity604is large enough to allow the control wire118to pass therethrough, but not large enough to allow the ball140pass therethrough. To assemble the control wire118with the yoke204according to the exemplary embodiment, the proximal end of wire140is inserted into the ball cavity602until the ball bottoms out, and then the control wire118is rotated until it is seated in the control wire cavity604, thus constraining further movement of the ball140. According to the present embodiment, the yoke204may be made of a biocompatible metal such as stainless steel or a high strength polymer such as Ultem™.

According to embodiments of the present invention, the clipping device100may be scaled to fit the requirements of different surgical procedures. In one exemplary embodiment, the clipping device100may be sized to fit through an endoscope having a working channel diameter of approximately 0.110 inches. The exemplary bushing may have a length of about 0.22 inches and an OD of approximately 0.085 inches. The capsule may have a length of about 0.5 inches, an OD of about 0.085 inches, and a wall thickness of about 0.003 inches. When assembled, the rigid length of the capsule200and the bushing202is approximately 0.625 inches. This length is important because if it is too great, the assembly will not pass through the bends of the flexible endoscope. In the exemplary clipping device, the outer sheath may have an ID of approximately 0.088 inches and an OD of about 0.102 inches. The overall length of the clipping device may be approximately 160 inches, while the tissue grasping portion of the clip arms208may be approximately 0.4 inches long.

Several aspects of the present invention are described below. In one aspect, the present invention is directed to an apparatus for deployment of a hemostatic clip comprising a handle assembly, a shaft connected to a distal portion of the handle assembly, a clip assembly releasably coupled to a distal portion of the shaft, the clip assembly including clip arms and a capsule cooperating with the clip arms to provide a first user feedback indicating a decision configuration of the clip assembly, and a control wire including a ball connector, the control wire extending from the handle assembly and coupled to the clip assembly by the ball connector to maintain the clip assembly coupled to the shaft, wherein the ball connector is detachable from the clip assembly to provide a second user feedback indicating separation of the clip assembly from the shaft.

The apparatus further includes an over sheath movable between a first position covering the shaft and the clip assembly and a second position uncovering the clip assembly. The over sheath has an over sheath stop engageable on the shaft to prevent movement of the over sheath to the second position.

The clip arms further comprise stop shoulders engaging a distal end of the capsule to provide the first user feedback during proximal movement of the control wire. The decision configuration indicates a position of the control wire beyond which further proximal movement of the control wire precludes return of the clip arms to an open configuration by a reversed movement of the control wire.

The capsule of the apparatus for deployment of a hemostatic clip further comprises a yoke including a ball cavity and being slidable within the capsule, the yoke receiving the ball connector in the ball cavity, and a tension member releasably connected to the yoke, the tension member being connected to the clip arms and biasing the clip arms toward an open configuration, wherein the tension member releases from the yoke when the control wire is moved proximally beyond the position at which the first user feedback is provided. The tension member and the yoke are releasably connected to one another by a male C section member and a female C section member. Separation of the yoke and tension member occurs by one of fracture and deformation of the male C section member.

In the apparatus for deployment of a hemostatic clip, separation of the yoke and tension member occurs when a tension on the control wire tension is at least a predetermined separation tension. For example, the separation tension is at least approximately 4 lbf, or alternatively may be less than approximately 12 lbf. The separation of the yoke and tension member locks the clip arms in a closed configuration by sliding the tension member and the clip arms proximally within the capsule. Separation of the yoke and tension member also allows proximal movement of the yoke to release the capsule from a bushing of the shaft. Distal movement of the control wire, before separation of the yoke from the tension member, slides the clip arms distally out of the capsule into an open configuration.

In the apparatus for deployment of a hemostatic clip, the first feedback includes a tactile and aural feedback. The control wire further comprises a reduced diameter section adjacent to the ball connector, the reduced diameter section yielding when a tension in the control wire reaches a predetermined yield tension. The yield tension is greater than the separation tension, and may be between approximately 10 lbf and 20 lbf.

In another aspect, the invention is directed to a clip deployment apparatus insertable to locations within a body through an endoscope. The apparatus includes an elongated member extending from a proximal end to a distal end, a control wire extending from the proximal end of the elongated member to the distal end thereof, a bushing coupled to the distal end of the elongated member, and a capsule releasably connected to the bushing. The apparatus further includes clip arms slidable within the capsule between a distal open configuration and a proximal closed configuration, a tension member slidable with the clip arms, the tension member biasing the clip arms toward the open configuration, and a yoke slidable within the capsule, a first end of the yoke being releasably connected to the tension member and a second end of the yoke being connected to the control wire, wherein distal movement of the control wire slides the clip arms into the open configuration, and proximal movement of the control wire slides the clip arms into the closed configuration.

In the apparatus described above each of the clip arms comprises a radius section and wherein the capsule comprises a plurality of overhangs cooperating with the radius sections to retain the clip arms in the closed configuration when the clip arms are moved proximally within the capsule. Each of the clip arms also comprises stop shoulders and wherein the capsule comprises a plurality of distal folding tabs cooperating with the stop shoulders to provide a first user feedback indicative of proximal movement of the clip arms through a selected position in the capsule. The first user feedback includes an aural component and a tactile component.

The proximal movement of the control wire beyond a point at which the clip arms are in the selected position results in separation of the yoke from the tension member. The separation of the yoke from the tension member precludes returning the clip arms to the open configuration and allows further proximal movement of the yoke to release the capsule from the bushing.

The apparatus described further comprises a ball and socket connection between the yoke and the control wire. That ball and socket connection includes a ball detachably coupled to a body of the control wire when a tension on the control wire is at least a predetermined separation tension, the ball providing a second user feedback when separated from the body of the control wire.

In yet another aspect, the invention is directed to a method for hemostatic clipping comprising inserting a shaft of a clipping device through a working lumen of an endoscope, wherein the shaft extends to a distal clipping assembly of the clipping device including a plurality of clip arms and wherein a control wire extends through the shaft from the clipping assembly to a handle coupled to a proximal end of the shaft. The method also comprises manipulating the handle assembly to move a control wire within the shaft to move the clip arms between an open and a closed configuration, generating a first user feedback indicating a decision configuration of the apparatus, and generating a second user feedback indicating separation of the clipping assembly from the shaft.

The method according to the present invention further comprises covering the shaft and the clipping assembly with an outer sheath and sliding the outer sheath proximally to uncover the clipping assembly. The clipping assembly further comprises a capsule slidably containing a yoke and a tension member biasing the clip arms toward the open configuration, the yoke being coupled to the control wire and being detachably coupled to the tension member.

The step of giving the first user feedback comprises providing a resistance force ending proximal movement of the clip arms and increasing a resistance to a corresponding movement of the handle assembly. Also included is separating the yoke from the tension member when a tension applied to the control wire after generation of the first user feedback is at least a first pre-selected tension. The second user feedback is generated when a reduced diameter portion of the control wire yields when a tension applied to the control wire is at least a second pre-selected tension, which may be greater than the first pre-selected tension.

The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts without departing from the teaching of the invention. Accordingly, various modifications and changes may be made to the embodiments without departing from the broadest scope of the invention. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.

The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts without departing from the teaching of the invention. For example, different shapes of the yoke, the tension member and the bushing may be used, and different attachments of the clip arms and control wire may be employed. Accordingly, various modifications and changes may be made to the embodiments without departing from the broadest scope of the invention as set forth in the claims that follow. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.