Endoscopic clip applying apparatus with improved aperture for clip release and related method

An apparatus for applying surgical clips includes a jaw assembly and a jaw opening member. The jaw assembly includes first and second opposing pivotable jaw members that define a variable-width jaw aperture therebetween for receiving a clip. The jaw opening member is movable into engagement with the first and second jaw members for increasing the width of the jaw aperture, thereby improving the release of a clip from the jaw assembly.

TECHNICAL FIELD

The subject matter disclosed herein generally relates to an applier for surgical clips. More particularly, the subject matter disclosed herein relates to an endoscopic ligating clip applier capable of sequentially delivering a number of clips in a clip channel.

BACKGROUND ART

Laparoscopic, endoscopic, and other minimally invasive surgical techniques enable surgeons to perform fairly complicated procedures through relatively small entry points in the body. The term “laparoscopic” refers to surgical procedures performed on the interior of the abdomen, while the term “endoscopic” refers more generally to procedures performed in any portion of the body. Endoscopic surgery involves the use of an endoscope, which is an instrument permitting the visual inspection and magnification of a body cavity. The endoscope is inserted into a body cavity through a cannula extending through a hole in the soft tissue protecting the body cavity. The hole is made with a trocar, which includes a cutting instrument slidably and removably disposed within a trocar cannula. After forming the hole, the cutting instrument can be withdrawn from the trocar cannula. A surgeon can then perform diagnostic and/or therapeutic procedures at the surgical site with the aid of specialized medical instruments adapted to fit through the trocar cannula and additional trocar cannulas providing openings into the desired body cavity.

Some known advantages of minimally invasive surgical techniques include reduced trauma to the patient, reduced likelihood of infection at the surgical site, and lower overall medical costs. Accordingly, minimally invasive surgical techniques are being applied to an increasingly wider array of medical procedures.

Many surgical procedures require body vessels to be ligated during the surgical process. For example, many surgical procedures require cutting blood vessels (e.g., veins or arteries), and these blood vessels may require ligation to reduce bleeding. In some instances a surgeon may wish to ligate the vessel temporarily to reduce blood flow to the surgical site during the surgical procedure. In other instances a surgeon may wish to permanently ligate a vessel.

Vessel ligation may be performed by closing the vessel with a ligating clip, or by suturing the vessel with surgical thread. Performing vessel ligation using surgical thread requires complex manipulations of the needle and suture material to form the knots required to secure the vessel. Such complex manipulations are time-consuming and difficult to perform, particularly in endoscopic surgical procedures, which are characterized by limited space and visibility. By contrast, ligating clips are relatively easy and quick to apply. Accordingly, the use of ligating clips in endoscopic surgical procedures has grown dramatically.

Ligating clips may be classified according to their geometric configuration as either symmetric clips or asymmetric clips, and according to the material from which they are manufactured. Symmetric clips are generally “U” or “V” shaped metallic clips that are substantially symmetrical about a central, longitudinal axis extending between the legs of the clip. By contrast, asymmetric clips lack an axis of symmetry. For example, U.S. Pat. No. 4,834,096 to Oh et al. describes a polymeric, asymmetric surgical clip in which a first leg member includes a lip that mates with the second leg member to lock the clip in place. Asymmetric clips have certain advantages over symmetric clips. For example, because asymmetric clips are formed from polymeric materials, the mouths of asymmetric clips can be opened wider than the mouths of symmetric clips. This allows a surgeon to position the clip about the desired vessel with greater accuracy. In addition, a clip of the type described in U.S. Pat. No. 4,834,096 can be repositioned before locking the clip on the vessel, a process referred to as “approximating” the clip, or to be removed from the vessel.

Ligating clips are applied using mechanical devices commonly referred to as surgical clip appliers, ligating clip appliers, or hemostatic clip appliers. Surgical clip appliers adapted for endoscopic surgical techniques include a shaft adapted to be inserted through an endoscopic cannula to access a surgical site in a body cavity and a jaw assembly disposed at the distal end of the shaft for retaining a surgical clip. In use, the clip is positioned over the desired vessel and the jaw is actuated, typically using a mechanism disposed in the handle of the device, to close the clip about the vessel.

Multiple clip applier systems have been developed that enable surgeons to deliver multiple symmetric surgical clips to an endoscopic surgical site. In general, these systems provide a surgical clip channel within the shaft of the device and a mechanism for delivering the surgical clips through the shaft to the jaw assembly. For example, U.S. Pat. Nos. 5,100,420 and 5,645,551 to Green et al. describe a device for delivering and applying multiple surgical slips to an endoscopic surgical site. Similarly, U.S. Pat. No. Re 35,525 to Stefanchik et al. aims to provide an endoscopic multiple ligating clip applier with a venting system. U.S. Pat. No. 5,700,271 to Whitfield et al., European Published Patent Application No. 0 409 569 A1, and European Patent No. 0 596 429 B1 propose other clip applier designs.

As endoscopic techniques have been developed, certain inadequacies in the available surgical equipment have become apparent. For example, the jaws of the applier, which are typically used to close a clip around a vessel, may exert unequal pressure on the clip, resulting in a “scissoring” effect and damage to the vessel. In other instances, the clip may not be properly oriented when it is placed within the jaws or may slip out of alignment during application. This may result in the loss or misapplication of the clip. In still other instances, the applier may jam or may simply fail to deploy a clip.

Furthermore, existing multiple clip applier systems have been designed for symmetric clips and are not well suited to satisfy design issues unique to asymmetric clips. For example, symmetric clips can be retained in clip jaws by holding opposing surfaces of the clip's legs in opposing channels. By contrast, asymmetric clips cannot easily be retained in opposing channels because the clip's legs deform when the clip is closed. In addition, when symmetric clips are closed on a vessel, the opposing legs of the clip apply substantially even pressure to the opposing sides of the vessel. By contrast, the opposing legs of an asymmetric clip may apply varying pressure to opposing sides of a vessel when the asymmetric clip is closed. Moreover, locking asymmetric clips of the type described in U.S. Pat. No. 4,834,096 function best when force is applied at or near the distal ends of the clip legs. Still further, asymmetric clips of the type described in U.S. Pat. No. 4,834,096 may need to be placed under compression to be retained in the clip channel. Thus, conventional clip advancing mechanisms designed for symmetric clips may not reliably advance asymmetric clips. In addition, conventional clip advancing mechanisms designed for symmetric clips may not provide the ability to approximate a clip.

Therefore, conventional clip appliers designed for symmetric, metal clips suffer from certain deficiencies and are not adapted to deliver asymmetric, polymer based clips. Accordingly, there is a need to provide an endoscopic clip applier that can reliably deliver a sequence of clips and in a manner which minimizes the risk of damage to the vessel. Additionally, there is a need for an endoscopic clip applier adapted to deliver asymmetric, polymeric ligating clips.

The foregoing problems have been addressed in whole or in part by an endoscopic clip applier adapted for delivering asymmetric, polymeric clips disclosed in copending, commonly assigned U.S. patent application Ser. No. 09/905,679, published as U.S. patent application Publication No. US 2003/0014060 A1, the content of which is incorporated herein in its entirety. In the use of such clip appliers, it has been found that difficulties may sometimes arise when attempting to release an applied clip from the jaws of the clip applier. Specifically, in some instances, clips may tend to become caught or hung up in the jaws in a manner that impedes their easy release therefrom. The subject matter disclosed herein is provided to address this issue.

SUMMARY

According to one embodiment, an apparatus for applying surgical clips comprises a jaw assembly and a jaw opening member. The jaw assembly comprises first and second opposing jaw members defining a jaw aperture therebetween for receiving a clip. The first and second jaw members are pivotable for varying a width of the jaw aperture. The jaw opening member comprises a distal portion generally adjacent to the first and second jaw members. The distal portion is movable into engagement with the first and second jaw members for increasing the width of the jaw aperture.

According to another embodiment, an apparatus for applying surgical clips comprises an elongate assembly, a jaw assembly, and a jaw opening member. The jaw assembly comprises first and second opposing jaw members. The first and second jaw members are pivotably coupled to the elongate assembly, and define a variable-width jaw aperture therebetween for receiving a clip. The jaw opening member is disposed within the elongate assembly and comprises first and second flexible arms that are movable into engagement with the respective first and second jaw members.

According to yet another embodiment, an apparatus for applying surgical clips comprises a jaw assembly, an elongate member, and a jaw opening member. The jaw assembly comprises first and second opposing jaw members defining a jaw aperture therebetween for receiving a clip. The first and second jaw members are pivotable about respective first and second pivot points, and comprise respective first and second outer surfaces. The elongate member is movable into contact with the first and second outer surfaces for pivotably decreasing a width of the jaw aperture. The jaw opening member comprises first and second arms respectively engagable with the first and second outer surfaces for pivotably increasing the width of the jaw aperture.

According to still another embodiment, an apparatus for applying surgical clips comprises a jaw assembly, a feeding device, and a jaw opening member. The jaw assembly comprises first and second opposing jaw members defining a jaw aperture therebetween for receiving a clip. The first and second jaw members are pivotable for varying a width of the jaw aperture. The feeding device is axially movable toward the jaw aperture for feeding a clip therein. The jaw opening member is engagable with the feeding device for movement therewith, and is movable into engagement with the first and second jaw members for increasing the width of the jaw aperture.

In addition, a method is disclosed herein for improving the release of a clip from a clip applying apparatus. A jaw assembly of the clip applying apparatus is opened to increase a width of a jaw aperture defined between first and second opposing jaw members of the jaw assembly. A biasing force is imparted to the first and second jaw members to further increase the width of the jaw aperture, whereby the further increased width facilitates releasing the clip disposed in the jaw aperture from the clip applying apparatus.

It is therefore an object of the subject matter disclosed herein to provide an endoscopic clip applier with improved aperture for clip release and a method for increasing the jaw aperture so as to improve clip release.

An object having been stated hereinabove, and which is addressed in whole or in part by the subject matter disclosed herein, other objects will become evident as the description proceeds when taken in connection with the accompanying drawings as best described hereinbelow.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, an exemplary embodiment of an endoscopic clip applier10in accordance with the subject matter disclosed herein includes an elongate or shaft assembly generally designated20, a jaw assembly generally designated90disposed at a distal end thereof, and a handle assembly generally designated140disposed at a proximal end thereof. Handle assembly140includes a stationary grip142and a movable trigger144for actuating clip applier10. In use, jaw assembly90may be positioned inside a body cavity, for example by passing shaft assembly20through an endoscopic cannula, to apply a ligating clip to a body vessel.

FIG. 2Ais a perspective view andFIGS. 2B and 2Care exploded assembly views of an exemplary embodiment of shaft assembly20and jaw assembly90. Shaft assembly20includes an elongate member such as a cylindrical outer shaft member22, which may be formed from two semi-cylindrical outer shaft members22A and22B, respectively. It will be appreciated that outer shaft member22may be formed from a single tubular member, or may be of a rectangular or polygonal cross-section. Outer shaft member22includes a proximal flange, indicated by proximal flange half sections24A,24B extending from the cylindrical surface of shaft members22A and22B, respectively. Outer shaft member22further includes pin slots28A,28B formed in the cylindrical surface. In addition, the cylindrical surfaces of outer shaft members22A,22B include opposing channels26A,26B that define opposing slots when shaft member22is assembled. Outer shaft22may be formed from a suitably rigid material, e.g., a suitable polymer or metal.

With further reference toFIGS. 2A-2C, at the distal end, shaft22may taper from a cylindrical cross-section to a substantially rectangular cross-section. As best shown inFIG. 2C, the distal end section of shaft assembly20can include a collar32, which can be a separate component from outer shaft22. Collar32has keys34A,34B that interlock with key slots30A,30B formed in one or both of outer shaft members22A,22B for connecting collar32to outer shaft member22. As best shown inFIG. 18, collar32preferably is substantially rectangular in cross-section and includes four cam surfaces38A,38B,38C,38D and opposing keys36A,36B at its distal end. As also shown inFIG. 18, collar32can also be constructed from two pieces of halves. Collar32may be formed from suitably rigid material, e.g., a suitable polymer or metal. In other embodiments, outer shaft member22continuously transitions into collar32as a unitary structure. For instance, in the case of a two-piece unitary structure, outer shaft members22A and22B can include distal sections that, when assembled together, form collar32. Hence, collar32in at least some embodiments can be considered a collar portion or distal portion of outer shaft member22, as illustrated for example in the embodiment shown inFIGS. 26A-30.

Referring toFIG. 2C, a clip feed assembly, generally designated70, is disposed within outer shaft22and collar32. Clip feed assembly70includes a channel72for housing clips78(FIG. 2B), and a feeder bar80that is movable along the longitudinal axis of shaft22for moving clips78disposed in channel72toward the distal end of clip applier10. Channel72includes a pin hole74near the proximal end and a plurality of tabs76near its base. Channel72may be formed from suitably rigid material, e.g., a suitable polymer or metal.

Feeder bar80includes a pin slot82and a plurality of tabs84which act as clip advancing elements to move clips78in channel72toward the distal end of clip applier10. Each tab84may be formed by stamping or cutting a portion of the body of feeder bar80. Tab84remains attached to the body of feeder bar80at the proximal end of tab84. Each tab84may be bent or otherwise directed toward the interior of the clip channel72. Tabs84may have a substantially uniform length, which may be determined by the length and geometry of the endoscopic clip, and by the rigidity of the material from which feeder bar80is manufactured. Tabs84may be located along either the top or bottom (or both) edges of the side of clip channel72. Feeder bar80may be formed from suitably rigid material, e.g., a suitable polymer or metal.

As shown inFIG. 2B, shaft assembly20further includes a linking member or yoke, generally designated50, a portion of which is disposed within handle assembly140(FIG. 1), for translating longitudinal motion to feeder bar80and outer shaft22. Feeder bar80includes a tab86that rests adjacent an interior distal edge57of yoke50(see alsoFIG. 15C). A portion of the yoke body56extends along a portion of the length of feeder bar80and has a slot58that aligns with pin slot82when yoke50is connected to feeder bar80. Yoke50further includes a flange52and pin54on its proximal end. Yoke50may be formed from suitably rigid material, e.g., a suitable polymer or metal. A feeder spring60is positioned within body56of yoke50for biasing feeder bar80toward the distal end of yoke50. A tube spring62is positioned between flange52and a flange42(e.g., flange halves42A and42B) on knob40for biasing yoke50toward the proximal end of shaft assembly20. A knob spring64is disposed within knob40and biases outer shaft22in a proximal direction.

Referring toFIG. 2C, jaw assembly90is connected to the distal end of clip channel72. Jaw assembly90includes a first jaw member92having a first leg94and a second leg99connected by a bridge member104. First leg94includes a first cam surface96and a first jaw arm98, a second leg99includes a second cam surface100and a second jaw arm102. Bridge member104includes a slot106for receiving a conventional fastener (e.g., rivets, pins, screws, tabs, etc.) to connect first jaw member92to clip channel72. Jaw assembly90further includes a second jaw member110having a third leg112and a fourth leg118connected by a bridge member124. Third leg112includes a third cam surface114and a third jaw arm116, and fourth leg118includes a fourth cam surface120and a fourth jaw arm122. Bridge member124includes a slot126for receiving a conventional fastener (e.g., rivets, pins, screws, tabs, etc.) to connect second jaw member110to clip channel72. Jaw assembly90further includes a first guide130adapted to clip over first jaw arm98and third jaw arm116and a second guide132adapted to clip over second jaw arm102and fourth jaw arm122. Jaw assembly90may be formed from suitably rigid material, e.g., a suitable polymer or metal.

FIGS. 3A and 3Bare cross-sectional views of an assembled shaft assembly20of a clip applier10in accordance with the subject matter disclosed herein. When assembled, jaw assembly90, clip feed assembly70, and yoke50are connected as described herein and extend through outer shaft22. Knob40is mounted to the exterior of outer shaft22and secured using conventional fasteners (e.g., pins, rivets, screws, adhesives, etc.). A pin46extending through knob40and through pin hole74(FIG. 2C) in clip channel72retains clip channel72in a fixed position with respect to knob40. For clarity,FIG. 3Aillustrates a clip channel72having a single clip78, but it will be appreciated that clip channel72may be filled with a plurality (e.g., 2-100) clips. The diameter of outer shaft22can generally be determined by the diameter of the cannula through which outer shaft22must pass to enter a body cavity. Many existing surgical procedures use a cannula having an inner diameter measuring approximately 10 millimeters. Accordingly, in one embodiment of the invention, outer shaft22has an outer diameter slightly less than10millimeters. In an alternate embodiment, outer shaft22may be dimensioned to fit within a cannula having a diameter of 5 millimeters. It will be appreciated, however, that the diameter of outer shaft22is not critical to the invention; any other diameter may be used as desired.

Referring toFIGS. 4 and 5, handle assembly140includes a fixed grip142, which may be manufactured in two substantially symmetrical parts142A,142B. A trigger144is pivotally mounted to fixed grip142about a pivot point146. As best shown inFIG. 5, trigger144includes a grooved claw148that impinges on flange52to translate the rotary motion of trigger144about pivot point146to linear motion of yoke50relative to fixed grip142in the distal direction. Grooved claw148also receives pin54of yoke50. This arrangement enables a user to force yoke50in a proximal direction if necessary, which provides a safety feature. Fixed grip142further includes a rim150that secures flange42of knob40, such that knob40and clip channel72are maintained in a substantially fixed longitudinal position relative to fixed grip142. The entire shaft assembly20is rotatable about its longitudinal axis, and knob40includes fins44(FIG. 4) that facilitate rotating the shaft assembly20.

A ratchet key152extends from the rear of trigger144and contacts ratchet guide154to inhibit backward motion of trigger144through a portion of the actuation stroke. Preferably, the toothed surface portion of ratchet guide154corresponds to the range of motion trigger claw148covers while feeder bar80is moved forward to advance the clips in clip channel72(i.e., the feed stroke). The smooth surface portion of ratchet guide154preferably corresponds to the range of motion trigger claw148covers during the portion of the actuation stroke that closes jaw assembly90. When the device is actuated, the transition of ratchet key152from the ratchet surface portion to the smooth surface portion provides the user with tactile feedback indicating that the feed stroke is complete and a clip78has been fed to jaw assembly90. In addition, the smooth surface portion permits a user to approximate clip78.

Basic structural elements of one embodiment of a clip applier10have been described with reference toFIGS. 1-5. Alternate embodiments for some components, and the interaction of the structural elements and general operation of the device, will be described with reference toFIGS. 6-30.

FIG. 6is a partial cut-away, side view of the proximal end of clip applier10with the device in an unactuated state. Referring toFIG. 6, yoke50is biased to its most proximal position by tube spring62. In the unactuated state, jaw assembly90is partially open, as depicted inFIG. 1. Trigger144and yoke50, in combination, may be considered an actuation assembly for actuating clip feed assembly70and jaw assembly90.

FIG. 7is a side cut-away view of the proximal end of clip applier10with the device in a partially actuated state. Forward motion of yoke50places tube spring62under compression. In one embodiment, the spring coefficient of feeder spring60(FIG. 6) is higher than the amount of force required to advance feeder bar80. Therefore, feeder spring60effectively functions as a solid piece of material during the feed stroke.

Referring generally toFIGS. 6-8, according to one embodiment, the first portion of the stroke of trigger144is a feed stroke that advances yoke50and feeder bar80relative to the fixed clip channel72. When feeder bar80is advanced, tabs84engage clips78in clip channel72and advance clips78toward the distal end of clip applier10. The most distal clip78is fed into jaw assembly90(FIG. 1).FIGS. 8-10are partial cut-away views of clip feeder assembly70illustrating the advancement or indexing of clip78to the most distal position during the feed stroke. For clarity of illustration, the distal end of feed bar80has been cut-away inFIGS. 8-10.FIG. 8illustrates the beginning of a feed stroke, in which tab84of feeder bar80is brought into contact with a boss79A of clip78disposed in clip channel72. InFIG. 9, further actuation of trigger144(FIGS. 6 and 7) moves feeder bar80in a distal direction, which advances clip78toward the distal end of clip channel72. InFIG. 10, feeder bar80has advanced clip78to the most distal position in clip channel72. For clarity,FIGS. 8-10illustrate the advance of a single clip78toward the distal end of clip applier10, but it will be appreciated that clip channel72may include a plurality (e.g., 2-100) of clips78, each of which is advanced by a tab84of feeder bar80. In one exemplary embodiment, clip channel72holds twenty (20) clips78.

During the feed stroke, the most distal clip78is fed from clip channel72to jaw assembly90. In an exemplary embodiment, the distal end of clip channel72and feeder bar80include structural features adapted to feed the most distal clip78into jaw assembly90. Referring toFIG. 19, the distal end of feeder bar80includes a feeder tab88adapted to contact the central rear portion of the most distal clip78to push clip78into jaw assembly90. In addition, feeder bar80includes a foot member89that rotates the rear of the most distal clip78during the return stroke so the rear portion of clip78is positioned to contact feeder tab88. Preferably, the interior surfaces of jaw assembly90that receive clips78are of substantially the same width as clip channel72to provide a smooth transition between the clip channel72and jaw assembly90.

Referring toFIG. 20, the distal end of clip channel72includes a tab71that catches the boss on the most distal clip78when foot member89(FIG. 19) of feeder bar80rotates clip78during the return stroke, thereby limiting the rotation of clip78. In addition, opposing ribs73A,73B facilitate centering the rear of the most distal clip78(in the lateral direction) so the rear portion of clip78is positioned to contact feeder tab88(FIG. 19). The distal end of clip channel72further includes upper and lower tabs77A,77B to provide a surface that facilitates the transfer of clip78into jaw assembly90. In addition, opposing lateral tabs75A,75B serve to guide clip78into jaw assembly90and to inhibit lateral motion of the rear portion of clip78when clip78is in jaw assembly90.FIG. 20also provides a view of tabs76that inhibit clips78from sliding in a proximal direction during the return stroke of feeder bar80, and of tabs179A-179D for securing a jaw component to clip channel72.

According to one embodiment, clip applier10is configured such that further actuation of trigger144(FIGS. 6 and 7) functions to open a clip78disposed in jaw assembly90. Clips78are fed through clip channel72in a compressed configuration, which reduces the required diameter of shaft assembly22. The most distal clip78is fed into jaw assembly90in the same compressed configuration. As illustrated inFIG. 12, first arm98, second arm102, third arm116and fourth arm122of respective first leg94, second leg99, third leg112and fourth leg118of jaw assembly90include respective catch structures such as first hook98A, second hook102A, third hook116A and fourth hook122A. Hooks98A,102A,116A,122A limit the forward motion of clip78in jaw assembly90. Therefore, when further pressure is applied to the rear of clip78via feeder tab88of feeder bar80, the force is translated through the legs of clip78, which causes jaw assembly90(and clip78contained therein) to open wider. The width to which jaw assembly90can be opened may be limited by the cam surfaces38A-38D of collar32.

Following completion of the feed stroke, further actuation of the trigger144actuates jaw assembly90.FIG. 11is a side cut-away view of the proximal end of clip applier10with the device in a fully actuated state. Pin46is always in clearance with channel26in shaft member22. A rib149in handle body142limits the forward motion of claw148of trigger144, and hence limits the forward motion of yoke50.

FIGS. 12-14are perspective views of distal end of clip applier10illustrating jaw assembly90while it is being closed. Referring first toFIG. 12, following completion of the feed portion of the stroke, a clip78is positioned in jaw assembly90, which is in an open configuration. According to one embodiment, the second portion of the stroke of trigger144closes jaw assembly90. More particularly, referring toFIGS. 13-14, the second portion of the stroke moves outer shaft22in a distal direction relative to fixed grip142(FIG. 1), knob40(FIG. 1), and clip channel72(FIGS. 2B and 2C). As the outer shaft22and collar32are moved in a distal direction, cam surfaces38A-38D of collar32impinge on cam surfaces96,100,114,120, closing jaw assembly90. The use of four separate cams reduces the likelihood of scissoring as jaw assembly90is closed.

While jaw assembly90is closing, feeder tab88(FIG. 12) of feed bar80remains in contact with the rear of clip78. Closing jaw assembly90tends to drive the rear of clip78in a proximal direction, which increases the pressure between feeder tab88and clip78in jaw assembly90, thereby enhancing the stability of clip78in jaw assembly90. This enhanced clip stability is particularly advantageous when a surgeon is pushing a clip78onto a vessel.

Additional features of clip applier10will be explained with reference toFIGS. 12-15. Each jaw arm98,102,116,122terminates in a hook98A,102A,116A,122A, respectively. Hooks98A and116A of first jaw arm98and third jaw arm116cooperate to retain boss79A of clip78in jaw assembly90. Similarly, hooks102A and122A of second jaw arm102and fourth jaw arm122cooperate to retain boss79B of clip78in jaw assembly90. This configuration of jaw assembly90provides four distinct points of contact between jaw assembly90and clip78, which reduces the likelihood of jaw assembly90scissoring while it is closing. In addition, this configuration permits the force applied by jaw assembly90to be applied to the distal end of clip78, which facilitates locking clip78. The rear (i.e., proximal) portion of clip78is retained between tabs75A,75B extending from the distal end of clip channel72, which limits the range of lateral motion available to clip78. In addition, feed tab88(FIG. 12) of feed bar80prevents the rear (i.e., proximal) portion of clip78from being pushed back into clip channel72when clip78is being applied. Accordingly, clip78is maintained stable in three dimensions while retained in jaw assembly90.

According to one embodiment, only a portion of ratchet guide154(FIGS. 5 and 11) includes ratchet teeth. Preferably the length of ratchet guide154having teeth corresponds to the feed portion of the actuation stroke of trigger144. Reversing the direction of feeder bar80during the feed stroke may cause clip78to become unstable, or even to fall out of jaw assembly90. The teeth on ratchet guide154inhibit feeder bar80from being moved in a proximal direction during the feed stroke. A second portion of ratchet guide154, which preferably corresponds to the portion of the stroke during which jaw assembly90is closed, permits yoke50and outer shaft22to move freely in the distal direction and the proximal direction. This allows a user to “approximate” a clip78during the closing process, i.e., to partially close a clip78then to re-open jaw assembly90to reposition a clip78, if necessary.

In one embodiment, distal collar keys36A,36B provide a stop to prevent jaw assembly90from unintended closings during use, e.g., under compression as may be incurred during use in the body. Referring toFIG. 13, it can be seen that the distal portion of collar keys36A,36B include an inwardly-turned segment positioned to block leg members112and118from closing. However, leg members94,99,112, and118taper inwardly near the distal end of jaw assembly90. Therefore, as illustrated inFIG. 14, when outer shaft22is advanced, collar keys36A,36B advance past the respective tapers in leg members94,99,112and118, allowing jaw assembly90to close. Additionally, collar keys36A,36B function as cams to facilitate re-opening jaw assembly90after the device is actuated and outer shaft22retracts.

FIG. 14illustrates jaw assembly90in a substantially closed configuration. Further actuation of jaw assembly90will lock clip78. The distal motion of outer shaft22compresses knob spring64(FIGS. 2B and 2C) between flange24A,24B (FIGS. 2B and 2C) and the interior distal edge of knob40(FIGS. 2B and 2C), which provides the bias force to return trigger144and outer shaft22to their unactuated states (FIG. 6). After jaw assembly90is closed, the user may release trigger144, and the bias force provided by knob spring64urges outer shaft22and feeder bar80in a proximal direction. This “resets” clip applier10back to an unactuated state so that another clip may be fed to jaw assembly90.

During the reset sequence, tabs76(FIG. 20) on clip channel72inhibit clips78in channel72from moving in the proximal direction. Tabs84(FIG. 19) on feeder bar80move across clips78in clip channel72and snap into position behind the bosses of clips78. As feeder bar80moves proximally, foot member89of feeder bar80contacts boss79B (FIG. 12) of the most distal clip78in clip channel72, causing clip78to rotate. Rotation of the most distal clip78stops when boss79A (FIG. 12) contacts the most distal tab84of feeder bar80, which preferably positions the rear of clip78substantially in the center of clip channel72. As feeder bar80continues to move proximally, feed tab88is positioned adjacent the rear of the most distal clip78, ready for the next actuation cycle.

FIGS. 15A-15Billustrate alternate embodiments of a yoke in accordance with the subject matter disclosed herein.FIG. 15Ais a perspective view of an alternate embodiment of a two-part yoke, generally designated180, prior to assembly, andFIG. 15Bis a perspective view of yoke180after assembly. Yoke180includes a first body portion182and a second body portion184connected by a pin186. Feeder spring60(FIG. 6) may be disposed entirely within first body portion182of yoke180. In other respects, yoke180is substantially similar to yoke50. Advantages of a two-piece yoke180as depicted inFIGS. 15A-15Binclude better retention of feeder spring60within the body of yoke180and ease of assembly. FIG.15C is a perspective view of yoke50depicted inFIG. 2, but from the opposite side to illustrate interior distal edge57that receives tab86(FIGS. 2B and 2C) of feeder bar80.

FIGS. 16-17are perspective views of alternate embodiments of jaw assemblies, generally designated190and195, respectively, in accordance with the subject matter disclosed herein. The jaw assemblies190and195depicted inFIGS. 16-17are substantially similar to jaw assembly90, but are particularly advantageous when used with a clip applier J10having a shaft assembly20with a smaller diameter, e.g., 5 millimeters. The principal distinction between jaw assemblies190and195depicted inFIGS. 16-17and jaw assembly90is the elimination of bridge members104,124(FIG. 2C) in favor of making each jaw member a discrete component.

FIGS. 21-24are perspective views of the distal end of a clip applier, such as clip applier10as described above, illustrating an alternative embodiment of a jaw assembly, generally designated200.FIG. 21illustrates the distal end of clip applier10with collar or collar portion32removed to better illustrate jaw assembly200. Jaw assembly200includes a first jaw member210and a second jaw member220. First jaw member210includes a leg member212A and a proximal end member232connected to clip channel72at a pivot point216A. First jaw member210also includes a leg member212B and an associated proximal end member (not visible) connected to clip channel72at a pivot point (not visible) on the opposite side of clip channel72. Each leg member212A,212B has a respective outer cam surface214A,214B. The distal end of the portion of jaw assembly200that includes first jaw member210forms a first jaw218. Second jaw member220may be substantially identical to first jaw member210. Second jaw member220thus includes a leg member222A and a proximal end member234connected to clip channel72at a pivot point226A. Although not visible inFIG. 21, second jaw member220also includes another leg member222B (seeFIG. 26A) and proximal end member connected to clip channel72at a pivot point on the opposite side of clip channel72. Leg member222A has a cam surface224A and leg member222B (FIG. 26A) similarly has a cam surface224B (FIG. 26A). The distal end of the portion of jaw assembly200that includes second jaw member220forms a second jaw228. In some embodiments, tabs240,242extend from the surface of clip cartridge72on one or both sides thereof and function as cams to bias the respective proximal ends of jaw legs212A,222A and/or212B,222B outwardly. This tends to bias jaw assembly200toward a closed configuration.

It will be appreciated that jaws218,228may be opened and closed by pivoting jaw members210,220about respective pivot points216A,226A, and the opposing pivot points not visible inFIG. 21.FIGS. 22-24are sequential views of the distal end of clip applier10that illustrate closing jaw assembly200.FIG. 22depicts jaw assembly200in the clip feed or “jaw set” position, in which jaws218,228preferably are substantially aligned with surfaces of clip channel72to facilitate the smooth transfer of a clip78from clip channel72into jaw assembly200. Collar32limits the outward motion of the proximal ends (e.g., proximal end members232and234shown inFIG. 21) of jaw legs212A,222A,212B,222B, which preferably are dimensioned such that jaw assembly200is at rest as depicted inFIG. 22.

FIG. 23depicts jaw assembly200in an open configuration. As discussed above, driving a clip78forward in jaw assembly200will open jaw assembly200(clip78is omitted inFIG. 23for clarity of illustration). The opening of jaw assembly200is limited by contact between cam surfaces214A,214B and224A,224B of jaw members210and220and corresponding cam surfaces38A-38D of collar32.

FIG. 24depicts the jaw assembly200in a closed configuration. As described above in connection withFIGS. 12-14, when collar32is advanced, cams38A-38D impinge on cam surfaces214A,214B,224A,224B, which closes the jaw assembly200. Collar32includes slots (e.g., slots35A and35C and opposing slots not visible) that allow the proximal end members (e.g., proximal end members232and234shown inFIG. 21) of jaw legs212A,222A,212B,222B to extend outwardly so that jaws218,228can close.

FIG. 25depicts an alternate embodiment of a collar, generally designated250, that is particularly adapted for use with jaw assembly200depicted inFIGS. 21-24. Collar250is substantially similar to the collar32depicted inFIGS. 21-24, and includes a tab252that extends into the chamber defined by the collar250to prevent jaw members210,220from unintended closing, e.g., due to pressure inside the body cavity. When jaw assembly200is in the unactuated position or the partially-actuated position, tab252fits between leg members212A,222A to prevent jaw assembly200from closing. By contrast, when jaw assembly200is fully actuated, tab252moves distally, allowing jaw assembly200to close.

Referring now toFIGS. 26A-30, another embodiment of clip applier10is illustrated in which a jaw opening member300has been incorporated.FIGS. 26A,27A,28A, and29A generally correspond to a “rest” position of clip applier10. The “rest” position can correspond to the end of the return stroke or the beginning of the forward stroke of clip applier10, after jaw assembly200has reached full aperture and a clip78has been released therefrom.FIGS. 26B,27B,28B, and29B generally correspond to a “jaw set” position of clip applier10, in preparation for feeding a clip78into first and second jaws218and228as described previously.FIGS. 26C,27C,28C, and29C generally correspond to a feeding position of clip applier10, in which a clip78is being fed into first and second jaws218and228and just prior to first and second jaws218and228opening to full aperture.FIGS. 26A-26Cillustrate a top plan view of clip applier10, and specifically of jaw assembly200and the distal portion of outer shaft22that includes collar portion32.FIGS. 27A-27Cillustrate a side elevation view of clip applier10, as viewed from the perspective of line A-A indicated inFIGS. 26A-26C, with portions of outer shaft22and collar portion32removed to provide a clear view of jaw opening member300and its interaction with jaw assembly200.FIGS. 28A-28Cillustrate a cut-away view of clip applier10taken along line B-B indicated inFIGS. 27A-27C, providing a view generally of the inside of a top section of clip applier10from the vantage point of the central longitudinal axis of jaw assembly200and shaft assembly20generally coincident with line B-B.FIGS. 29A-29Cillustrated an enlarged view of section detail C shown inFIGS. 28A-28C.FIG. 30illustrates a reset position of clip applier10.

As will become evident from the following description, in connection with the description hereinabove of the general operation of clip applier10in its various embodiments, jaw opening member300interacts with jaw assembly200to increase the jaw aperture generally defined by the opening between first and second jaw members210and220, and thereby to improve the ability of clip applier10to release a clip78from first and second jaw members210and220at the time intended by the user. For instance, the operation of jaw opening member300can reduce the risk that one or more bosses of clip78snag or hang up on one or more of the surfaces of jaw assembly200with which clip78contacts. Generally, the increase in the jaw aperture will occur during the beginning and end of the stroke of clip applier10, which corresponds roughly to the time at which a clip78is released from jaw assembly200after having been applied to a target tissue of a surgical site.

As shown in the various views ofFIGS. 26A-30, jaw opening member300is disposed within outer shaft22. Jaw opening member300extends far enough into collar portion32, and generally on one side of outer shaft22and collar portion32, so as to interact with at least two opposing leg members of jaw assembly200, which are designated hereinafter as first leg member212A and second leg member222A (see, e.g.,FIG. 27A).

Referring toFIGS. 27A and 30, jaw opening member300is disposed generally adjacent to feeder bar80. Jaw opening member300includes a main portion or body302, a distal portion304nearest to jaw assembly200, and a proximal portion306farthest from jaw assembly200. Distal portion304is bifurcated into a first arm312and a second arm314such that first and second arms312and314can act as spring members. First arm312terminates at a first finger or extension316, and second arm314terminates at a second finger or extension318. First finger316and second finger318are directed generally inwardly into the interior of collar portion32. By this configuration, distal portion304of jaw opening member300straddles first and second proximal end members232and234of first and second jaw members210and220, respectively, thereby enabling first and second fingers316and318to respectively engage the portions of the outer surfaces of first and second jaw members210and220corresponding to first and second proximal end members232and234.

As shown inFIG. 27A, proximal portion306of jaw opening member300includes a cut-out section322in which a tab324is formed. Tab324is angled inwardly for contacting feeder bar80. As shown inFIG. 28Aand in greater detail inFIG. 29A, tab324terminates at an end portion324A that is angled inwardly to a greater degree than the remaining portion of tab324. End portion324A facilitates the engagement of tab324with a tab aperture325formed in feeder bar80, as described below.

It will be noted from the description herein that the jaws are spring loaded so as to be normally biased closed. Jaw opening member300acts to override the spring in a manner described herein

In accordance with the present embodiment, it can be seen fromFIGS. 27A and 30that an interfacial region is formed in jaw assembly200on the proximal side of pivot points216A and226A, where first and second leg members212A and222A transition into first and second proximal end members232and234, respectively. The interfacial region is generally demarcated by a ridge or shoulder262from which, in the proximal direction, first and second proximal end members232and234drop farther into the interior to provide clearance for first arm312and second arm314of jaw opening member300to straddle first and second proximal end members232and234. Ridge262can stop forward movement of jaw opening member300relative to jaw assembly200, as described below. In addition, it can be seen that first and second proximal end members232and234have respective sections of reduced width264and266just beyond ridge262in the proximal direction. From reduced-width sections264and266, first and second proximal end members232and234taper outwardly, becoming wider in the proximal direction to sections of increased width268and270. By this configuration, first and second fingers316and318can engage only increased-width sections268and270of first and second proximal end members232and234, when jaw opening member300is positioned rearward relative to jaw assembly200. If jaw opening member300is moved to a more forward position relative to jaw assembly200(see, e.g.,FIG. 27B), first and second fingers316and318will be adjacent to reduced-width sections264and266of first and second proximal end members232and234, at which first and second fingers316and318do not contact first and second proximal end members232and234and thus do not affect the width of the jaw aperture. As best shown inFIGS. 28A -28Cwith respect to second arm314, respective portions312A and314A of first and second arms312and314can be angled generally outwardly from feeder bar80to facilitate the positioning of first and second arms312and314over first and second proximal ends232and234.

FIG. 27Aillustrates the rest position of clip applier10. This position can correspond to a time just after a clip has been applied to a surgical site and released from jaw assembly200. The next distal-most clip residing in clip applier10, clip78inFIG. 27A, is positioned in clip channel72in preparation to begin the next clip feeding cycle as described hereinabove. At the position shown inFIG. 27A, first and second fingers316and318of jaw opening member300engage first and second proximal ends232and234of first and second leg members212A and222A. By means of the spring action of first and second arms312and314which is stronger than the jaw spring, first and second fingers316and318apply respective biasing forces on first and second proximal end members232and234. As a result, first and second proximal end members232and234are urged generally toward the centerline of clip applier10coincident with line B-B. Consequently, on the distal side of pivot points216A and226A, first and second leg members212A and222A are urged generally outwardly, as generally depicted by the arrows inFIG. 27A, thereby increasing the width of the jaw aperture and improving the ability of an applied clip to be released from jaw assembly200. Also at this position, as shown inFIG. 28Aand in greater detail inFIG. 29A, end portion324A of tab324of jaw opening member300extends into tab aperture325of feeder bar80. Hence, as feeder bar80is driven forward to contact clip78and feed clip78into jaw assembly200, feeder bar80can also drive jaw opening member300forward.

Referring now toFIGS. 26B and 27B, clip applier10is operated to actuate jaw assembly200into the jaw set position in preparation for feeding clip78into jaw assembly200, as described hereinabove. As feeder bar80is driven into engagement with clip78, feeder bar80carries jaw opening member300forward as generally depicted by the arrows in each ofFIGS. 27B-29B, due to the contact between end portion324A of tab324and tab aperture325shown inFIGS. 28B and 29B. As shown inFIG. 27B, the forward movement of jaw opening member300is limited by ridge264formed by leg members212A and222A of jaw assembly200. Ridge262acts as a stop against which first and second fingers316and318of jaw opening member300abut. At this position, first and second fingers316and318are adjacent to reduced-width sections264and266of proximal end members232and234of jaw members210and220. Due to reduced width sections264and266, first and second fingers316and318reduce the force on end members232and234and hence to do not operate to increase the jaw aperture. At this position, an increase in the jaw aperture is not desired because, as described previously, the jaw aperture is preferably set at a width that is substantially the same as that of clip channel72, so as to receive clip78in a compressed state that enables a smooth transition of clip78from clip channel72into jaw assembly200.

Referring now toFIGS. 26C-28C, clip applier10has been further actuated so as to advance clip78into jaw assembly200, as generally depicted by the arrow inFIG. 28C. As shown inFIG. 28C, the advancement of clip78is accomplished by driving feeder bar80farther in the distal direction. Feeder bar80moves forward relative to jaw opening member300during this stage of operation. That is, as shown inFIG. 27C, first and second fingers316and318of jaw opening member300remain abutted against ridge262of leg members212A and222A. As feeder bar80moves forward relative to jaw opening member300, tab aperture325(seeFIG. 29B) of feeder bar80necessarily moves relative to jaw opening member300as well. Hence, end portion324A of tab324of jaw opening member300is deflected because of angled end324A out from tab aperture325and, as shown inFIG. 29C, remains in contact with a surface of feeder bar80as feeder bar80and its tab aperture325continue to move forward and allowing the feeder bar80to move forward and feed the clip.

As described previously, after clip78has been fed into jaw assembly200, the continued forward stroke of clip applier10is executed to apply clip78to target tissue at the surgical site. Subsequently, clip78is fully released from jaw assembly200as jaw assembly200is opened to full aperture. As described previously with reference toFIG. 27A, the jaw aperture is increased to facilitate the release of clip78by the action of jaw opening member300in jaw assembly200. Subsequently, clip applier10can be reset during its return stroke as generally described hereinabove. Because tab324of jaw opening member300is essentially spring loaded and remains in contact with feeder bar80, as feeder bar80moves in the proximal direction during the return stroke, end portion324A of tab324eventually drops back down into tab aperture325, allowing feeder bar80to carry jaw opening member300back to the starting position shown inFIGS. 27A and 30.

Referring now toFIG. 30, if jaw assembly200is forced closed (as depicted by the arrows) while clip applier10is in the reset position, jaw opening member300is configured so as to allow such closure. Although jaw opening member300has been reset to a position at which its first and second fingers316and318respectively engage first and second proximal end members232and234of first and second jaw members210and220, first and second arms312and314of jaw opening member300act as springs and thus flex in response to the outward movement of proximal end members232and234that accompanies the closing of jaw assembly200.

It will be understood that various details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation, as the invention is defined by the claims as set forth hereinafter.