Abstract:
A ligation clip applicator design is provided that is particularly applicable to placement of a surgical ligation clip during a laparoscopic surgical procedure. The applicator has a magazine including first and second longitudinally extending partially closed channels within which enlarged portions of a ligation clip are received and held in an open position. First and second substantially parallel compression members are attached to the magazine and have first and second channel extensions therein aligned with the first and second channels of the magazine for receiving the first and second enlarged portions of the clip. The channel extensions include first and second releasing openings. The compression members close about a vessel, remaining substantially parallel as they close. The clip is pushed forward into the compression members to a position where the enlarged portions of the clip are aligned with the releasing openings, permitting the clip to be released to close and ligate the vessel.

Description:
[0001]     The present application claims the benefit of U.S. provisional Application No. 60/477,106, filed Jun. 9, 2003, and U.S. provisional Application No. 60/513,518, filed Oct. 21, 2003, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to mechanical devices used in surgical procedures to obtain ligation or hemostasis, and more particularly, to low profile tools that can apply a pre-formed, spring loaded ligation clip used during surgery to clamp around a vessel or duct, such as the cystic duct, and thereby obtain ligation.  
         [0004]     2. Description of the Prior Art  
         [0005]     It will be appreciated by those skilled in the art that the use of ligation clips to control bleeding during surgical procedures is well known. As described, for example, in U.S. Pat. Nos. 4,976,722 and 4,979,950, prior art clips are generally formed of metal wire, usually a titanium alloy, having a “U-shaped” rectangular cross-section. Such prior art clips often include a grooved pattern machined into the inner or clamping surfaces of the clip, in an attempt to enhance the ability of the clip to remain in position after it is closed around the vessel. Application of the clip to the vessel is normally effected by means of a crushing action produced by a clip applier, such as disclosed in U.S. Pat. No. 5,030,226. Such crushing actions, of course, permanently deform the clips, making them difficult to remove or re-position.  
         [0006]     Prior art surgical ligation clips have several inherent problems. For example, the force applied by the clip to the vessel can be variable and inconsistent from one clip to the next, because of the variation in crushing force applied to the clip by the user. Further, prior art clips have a tendency to slip off the end of the blood vessel stub (i.e., perpendicular to the axis of the vessel) to which it has been applied, because of the low coefficient of friction associated with the clip, and lack of adequate restraining force provided by the clip. Because of this, separation of the clip from the vessel to which it has been applied, after the wound has been closed, is not uncommon. A related problem found in the prior art is the fact that the ligating or restraining force offered by the crushed clip varies along the length of the clip, decreasing toward the open end. Thus, the section of the vessel near the open end of the clip can be inadequately ligated.  
         [0007]     It is also common in the prior art to actually form and crush the clip only at the time of its application to the targeted blood vessel. It is often required that the vessels of 4 mm and larger diameter be ligated. Because most clips of the prior art have no spring action it is required that the inside clearance dimension of the clip, prior to crushing, be larger than the vessel. This does not lend itself to clip applier designs that will pass through small 5 mm trocars. The applier must be inserted through a trocar, placed through the patient&#39;s external tissues, and into the surgical field. Thus, prior art ligation clip appliers used in laparoscopic procedures typically consist of a 10 mm diameter clip applier that can fit only through a trocar having a 10 to 11 mm diameter entry port. Because one goal of laparoscopic surgery is to minimize the size of the entry wound, a surgical ligation clip and clip applier that can be used within a 5 mm or even a 2.5 mm diameter trocar port is highly desirable.  
         [0008]     New minimally invasive surgical procedures and the need for less invasiveness for current procedures require the development of smaller and smaller devices. The harvesting of saphalous veins and certain cardiovascular procedures would benefit from reduced diameters trocars, below 3 mm diameter.  
         [0009]     To address these problems a spring action surgical clip was designed, and is disclosed in U.S. Pat. No. 5,593,414, titled “Method of Applying a Surgical Ligation Clip,” the disclosure of which is incorporated herein by reference. One embodiment of the clip disclosed in the &#39;414 patent is shown in  FIGS. 1 and 2 . Clip  50  has a vessel clamping arm  52 , a vessel support member  54 , and at least one tension coil  56  integrally joining the arm and support member. Clip  50  is pre-formed so that in its equilibrium state, it can be easily placed within the surgical field, including through an endoscopic trocar port with a diameter as little as 5 mm. After the clip is placed proximate the blood vessel or duct to be clamped, clamping arm  52  is moved from its equilibrium position to a position under higher tension, allowing positioning of the vessel between arm  52  and support member  54 . When correct placement and positioning is achieved, arm  52  is released and, as the arm tends to move back towards its equilibrium position, it clamps the vessel between the arm&#39;s curved lower surface and the supporting upper surface of vessel support member  54 .  
         [0010]     To enhance the performance of the tension coil(s), vessel support member  54  includes first and second arms  58 ,  60 , one of which terminates in a 180-degree bend section. Minimal cross-sectional area of the clip is achieved by substantially longitudinally aligning the vessel support member, the clamping arm, the 180-degree bend section  62 , and the tension coil.  
         [0011]     The clamping arm is pre-formed into an equilibrium that generally aligns with the horizontal plane of the support member. A second embodiment of the clip pre-loads the clamping arm into a pre-loaded equilibrium position where the free end of the arm rests against the upper surface of the support member.  
         [0012]     There exists a relationship between the diameter of the trocar (hence the applier tube) and the maximum diameter of a vessel that can be ligated. Older crush clip technology limits the ratio of wound size to maximum diameter to be ligated to greater than 2. That is, to ligate a 5 mm vessel, a puncture wound of 10-12 mm is required. U.S. Pat. No. 5,593,414 teaches the method of using a spring clip that is inserted into the surgical field in the closed state, opened over a vessel, the diameter of which has been reduced, or pre-clamped, by the tool, and closed over the pre-clamped vessel. This method allows an entry wound to vessel diameter ratio of 1 or smaller. Thus, a 5 mm vessel can be ligated through a 5 mm trocar. This is substantially less invasive as compared to the older crush clip technology. For a trocar diameter of 2.5 mm, the clip can be scaled down to approximately half size on the wire diameter, coil height, and length, yet still supply an acceptable ligation force on a 2.5 mm vessel.  
         [0013]     Unfortunately, several problems are encountered in applying the spring-action ligation clip of U.S. Pat. No. 5,593,414 to a vessel through a 5 mm or smaller trocar port. First, the nominal 5 mm cross-section of the clip that is inserted through the trocar places severe design restrictions on any applier mechanism. Second, care must be taken so that the elastic limit of the spring material is not exceeded when the clip is opened up so that it can be placed over the vessel diameter. For a titanium wire of diameter 0.75 mm, for example, lifting a distal end of a spring clip much above a few mm will exceed the elastic limit. Secondly, these spring clips are small and compact and owing to the preload, have a great deal of energy stored in the spring. As these clips are opened to place them over a vessel the stored energy increases substantially, in some cases more than doubling. This energy makes controlling the clip, to insure proper installation, difficult. Undesirable translation or rotation can result in misplacement or dropping of the clip inside the body.  
         [0014]     Another approach which has been proposed to provide smaller diameter endoscopic clip application is that of U.S. Pat. No. 5,601,573 to Fogelberg et al. Fogelberg et al. still struggles with the complex manipulation required to advance the clip in a closed position and then open the clip prior to placement. Fogelberg et al. also has an overly complex multi-stage trigger arrangement for actuation of the jaws and the clip advancement mechanism. The present invention presents several improvements over Fogelberg et al. including: (1) advancement of the clips in their open position rather then a closed position; and (2) a smooth single stage trigger action which simultaneously closes the jaws and advances the forward most clip into the jaws. Another difference between the present invention and Fogelberg et al. is that Fogelberg et al. pushes a stack of clips, whereas the present invention individually engages and pushes each clip simultaneously, thus yielding better control of the clips.  
         [0015]     The clip and clip applier disclosed in U.S. Pat. No. 6,350,269, titled “Ligation Clip and Clip Applier,” the disclosure of which is incorporated herein by reference, represents a further improvement over the Fogelberg et al. device. The &#39;269 patent discloses a clip having wire loops at one end thereof and a clip applier that utilizes the loop width to open and release the clip around a vessel.  
         [0016]     There are several problems associated with the spring clip applicators of the prior art. First, the jaws are usually designed such that either one is stationary and the other rotates closed about the fixed jaw, or both jaws rotate in a scissor-like fashion about a common axis. This creates a severe pinching force on tissue that might be located near the axis or pivot point. This pinching force can cause a hematoma or otherwise damage the tissue. Secondly, the diverging surfaces of the jaws often obstruct the surgeon&#39;s view of the tissue to be ligated owing to the acute angle of the laparoscopic camera and the clip applier.  
         [0017]     What is needed then is a clip applier with jaws that do not apply an unduly high force anywhere on the tissue to be ligated. What is also needed is a clip applier with jaws that are substantially parallel to each other in an open position so that the surgeon has a better view of the tissue to be ligated.  
       SUMMARY OF THE INVENTION  
       [0018]     In one preferred embodiment of the present invention, a surgical ligation apparatus for compressing a fluid carrying structure includes a proximal end, an opposite distal end, a mid-longitudinal axis passing through the proximal and distal ends, and a shaft having a passage adapted to receive at least one surgical ligation clip therein. The apparatus further includes upper and lower compression members proximate the distal end of the apparatus, each of the upper and lower compression members having a clamping surface for contacting the fluid carrying structure. The clamping surfaces each have a forward portion proximate the distal end of the apparatus and an opposite rearward portion. The rearward portions of the upper and lower clamping surfaces are moveable relative to one another a distance that is generally equal to a distance that the forward portions of the upper and lower clamping surfaces are moveable relative to one another to compress the fluid carrying structure between the clamping surfaces.  
         [0019]     In another preferred embodiment of the present invention, a method of ligating a fluid carrying structure having a width includes inserting into a patient a surgical ligation instrument having upper and lower clamping surfaces moveable relative to one another between an open position for receiving the fluid carrying structure and a closed position for compressing the fluid carrying structure therebetween. The upper and lower clamping surfaces are adapted to contact the fluid carrying structure. The method further includes positioning the fluid carrying structure between clamping surfaces of the instrument; applying a substantially uniform compression across the width of the fluid carrying structure; moving a ligation clip over a portion of the clamping surfaces of the instrument, the ligation clip being resiliently biased to a closed position; and releasing the ligation clip to permit the ligation clip to move to the closed position.  
         [0020]     These and other objects of the present invention will be apparent from review of the following specification and the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a top plan view of a surgical ligation clip disclosed in the prior art.  
         [0022]      FIG. 2  is a side elevation view of the surgical ligation clip of  FIG. 1 .  
         [0023]      FIG. 3  is a top plan view of a surgical ligation clip in accordance with another embodiment of the present invention, the surgical ligation clip being engaged about a vessel.  
         [0024]      FIG. 4  is a perspective view of the surgical ligation clip of  FIG. 3 .  
         [0025]      FIG. 5  is a side elevation view of a clip applier having a distal end with a pair of compression members in an open position in accordance with one embodiment of the present invention.  
         [0026]      FIG. 6  is a side elevation view of the clip applier of  FIG. 5  with the compression members in a closed position.  
         [0027]      FIG. 7  is an enlarged view of a push rod for individually engaging a plurality of surgical ligation clips.  
         [0028]      FIG. 8A  is a partial side cross sectional view of the clip applier of  FIG. 5 .  
         [0029]      FIG. 8B  is an enlarged fragmentary cross sectional view of the distal end of the clip applier of  FIG. 8A .  
         [0030]      FIG. 8C  is a cross sectional view along line  8 C- 8 C of  FIG. 8B .  
         [0031]      FIG. 9A  is a partial side cross sectional view of the clip applier after discharging the clip.  
         [0032]      FIG. 9B  is an enlarged fragmentary cross sectional view of the distal end of the clip applier of  FIG. 9A .  
         [0033]      FIG. 9C  is a cross sectional view along line  9 C- 9 C of  FIG. 9B .  
         [0034]      FIG. 10  is an exploded perspective view of the upper and lower compression members of the clip applier of  FIG. 5 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0035]     Reference will now be made in detail to the present preferred embodiments (exemplary embodiments) of the invention, examples of which are illustrated in the accompanying drawings.  
         [0036]      FIGS. 3 and 4  show an example of a surgical ligation clip  100  usable with a preferred embodiment of the clip applier of the present invention. Surgical ligation clip  100  includes a clamping arm  106  and a support member  108 . A coil tension spring  110 , which may also be generally referred to as a connector, joins clamping arm  106  and support member  108 .  
         [0037]     Clamping arm  106  has a first enlarged end  102  defined thereon. Support member  108  has a second enlarged end  104  defined thereon. The first and second enlarged ends  102 ,  104  are first and second wire loops which are integrally formed with clamping arm  106  and support member  108  of clip  100 .  
         [0038]     Loops  102 ,  104 , and particularly the laterally outer portions thereof, may be described as first and second control surfaces being received in and trapped within the first and second channels of a clip carrier  216 . As best seen in  FIG. 8A , a plurality of ligating clips  100  are received in clip carrier  216 , in a semi-open position. For ease of identification, consecutive clips beginning with the forward-most one are designated as  100 A,  100 B,  100 C, etc. The control surfaces, as engaged by the channels of clip carrier  216 , prevent rotation and yawing of clip  100  as the clip is moved through the clip carrier.  
         [0039]     The connector of clamping arm  106  and support member  108  is preferably a coil spring  110  which has a preload that biases the support member  108  and clamping arm  106  toward each other. The preload is preferably such that when clip  100  is in the fully closed or pre-loaded equilibrium position shown in  FIG. 9B , there is still a spring preload in the connector which forces wire loops  102 ,  104  against each other.  
         [0040]      FIGS. 5 and 6  show one preferred embodiment of a clip applier  200  in accordance with the present invention. Clip applier  200  includes a distal end  202 , a proximal end  204 , and a tubular shaft  206  therebetween. Distal end  202  includes upper and lower compression members  208 ,  210  that are moveable between an open position, shown in  FIG. 5 , and a closed position, shown in  FIG. 6 .  
         [0041]      FIG. 7  shows a pusher rod  212  which has a plurality of prongs  214  extending therefrom for engagement with clips  100  contained in a clip carrier  216  as seen in  FIG. 8A . Pusher rod  212  is preferably an elongated flat bar. Pusher rod  212  is slidably received in a channel within passage  218  of shaft  206 .  
         [0042]     As shown in  FIGS. 8A and 8C , clip carrier  216  includes a pair of opposed rails  220 ,  222  projecting from the interior sides of the clip carrier which define partially closed upper and lower channels. Rails  220 ,  222  extend along the length of clip carrier  216  and are configured to maintain clips  100  in a slightly open position as they are moved along the length of clip carrier  216  and into engagement with compression members  208 ,  210 .  
         [0043]      FIG. 10  shows upper and lower compression members  208 ,  210 . Compression members  208 ,  210  each include a clamping surface  224  configured to contact a fluid carrying structure. Clamping surface  224  includes a forward portion  226  proximate the distal end of the compression member and a rearward portion  228 . If desired, clamping surface  224  may include a plurality of grooves and ridges  225  along the length of the clamping surface to provide additional grip. Upper and lower compression members  208 ,  210  also include an extension rail  230  vertically opposite clamping surface  224  that leads to a loop releasing openings  232 ,  233 . The exterior surface of the forward end of each compression member is preferably blunt-shaped to minimize interference with surrounding tissue structures.  
         [0044]     Upper and lower compression members  208 ,  210  are attached to the distal end of clip carrier  216  by a pair of laterally extending pins  234 ,  236 , respectively. Pins  234 ,  236  are configured for engagement with a slot  238  positioned proximate the distal end of clip carrier  216  in the interior sidewall of the clip carrier. Upper and lower compression members  208 ,  210  are biased to an open position by a pair of springs  240  receivable in spring receiving openings  242 . The proximal end of each of upper and lower compression members  208 ,  210  include a ramp  244 ,  246 , respectively. Ramps  244 ,  246  each include longitudinal recesses  248 ,  250 , respectively, configured to receive portions  252 ,  254 , respectively, of clip carrier  216  as shown in  FIGS. 8C and 9C .  
         [0045]     With reference to  FIGS. 8A-8C  and  9 A- 9 C, the operation of clip applier  200  will now be described.  FIGS. 6 and 8 A- 8 C show clip applier  200  with upper and lower compression members  208 ,  210  in the open position. After a surgeon has inserted clip applier  200  through a trocar and into a patient, the surgeon positions a fluid carrying structure such as a vessel V or stub end of a tissue between upper and lower compression members  208 ,  210 . Squeezing trigger  256  on the handle of clip applier  200  will cause shaft  206  to move forward relative to clip carrier  216  and upper and lower compression members  208 ,  210 . At the same time, crimp features  258 ,  260 , located on the interior wall of passage  218  of shaft  206 , advance guide  262  forward with shaft  206 . Trigger  256  is preferably a two-stage trigger so that a first squeeze will pre-clamp vessel V, as will be described below, and a continued second squeeze of trigger  256  will discharge clip  100 . A two-stage trigger permits the surgeon the opportunity to evaluate whether vessel V is sufficiently pre-clamped before discharging a clip. It will be appreciated by those skilled in the art that other trigger actuation mechanisms are within the scope of the present invention and that a two-stage trigger is only a preferred embodiment of the present invention.  
         [0046]     Guide  262  preferably has a circular outer diameter to match the interior diameter of passage  218 . Guide  262  has a central opening configured to permit passage of clip  100  therethrough and is defined at least in part by upper and lower guide surfaces  264 ,  266 , which are configured to move, preferably slide, against upper and lower ramps  244 ,  246  of upper and lower compression members  208 ,  210 , respectively, as shown in  FIGS. 8B and 9B . The central opening of guide  262  is preferably generally curved to match the curve of each of upper and lower ramps  246 ,  248  (see  FIG. 8C ).  
         [0047]     As guide  262  moves forward along the mid-longitudinal axis of clip applier  200 , ramps  244 ,  246  slide against guide surfaces  264 ,  266 , forcing an inward motion of upper and lower compression members  208 ,  210  toward one another. Laterally extending pins  234 ,  236  of upper and lower compression members  208 ,  210 , respectively, slide within slot  238  of clip carrier  216 , which acts as a guide surface for pins  234 ,  236  and maintains the horizontal parallel alignment of upper and lower compression members  208 ,  210  while the upper and lower compression members move toward each other. The inward force caused by guide  262  sliding against ramps  244 ,  246  overcomes the biasing force provided by springs  240 , which acts to keep upper and lower compression members  208 ,  210  in an open position. As would be appreciated by those skilled in the art, the length and slope of upper and lower ramps  244 ,  246  may be modified according to the dimensions of the clip to be used with the clip applier.  
         [0048]     The forward-most clip  100 A is pushed out of clip carrier  216  into upper and lower compression members  208 ,  210  by the next adjacent clip  10 B. As forward-most clip  100 A is pushed forward, the lateral sides of wire loops  102 ,  104  slide along rails  220 ,  222  of clip carrier  216  in a semi-open position owing to the biasing force towards the closed position of clip  100 A against each rail. Continued forward movement of clip  100  along the length of the clip applier brings the lateral sides of wire loops  102 ,  104  up a ramped portion of rails  220 ,  222 , over a ramp portion  268  of pins  234 ,  236 , and onto rail extension  230  within upper and lower compression members  208 ,  210  (shown in  FIG. 10 ). As wire loops  102 ,  104  come into registry with releasing openings  232 ,  233 , support member  106  and clamping arm  108  of clip  100 A snap shut toward each other, thus clamping vessel V therebetween as clip  100 A is released from upper and lower compression members  208 ,  210 , as shown in  FIGS. 9A-9C . The surgeon can view the discharge of the clip through windows  270 ,  272  in upper and lower compression members  208 ,  210 , respectively.  
         [0049]     After trigger  256  has been squeezed to close compression members  208 ,  210  and advance clip  100 A into the compression members where it is released, subsequent release of trigger  256  will pull back push rod  212 . The column of clips  100  will stay in place within clip carrier  216  due to the gripping of rails  220 ,  222  by clips  100 . Prongs  214  will slip back past the clips and engage the next rearward clip on the next squeeze of trigger  256 .  
         [0050]     When upper and lower compression members  208 ,  210  are closed together, a generally uniform vertical force is applied across the width of vessel V to occlude the vessel. The closing motion of compression members  208 ,  210  may be described as pre-clamping vessel V by movement of clamping surfaces  224  toward one another.  
         [0051]     It is noted that the step of pre-clamping vessel V between upper and lower compression members  208 ,  210  typically occurs prior to the step of pushing spring clip  100 A from clip carrier  216  into upper and lower compression members  208 ,  210 . As spring clip  100 A is moved into upper and lower compression members  208 ,  210 , it subsequently is released from those compression members when the wire loops move into registry with the releasing openings  232 ,  233 .  
         [0052]     It is further noted that the methods of operating clip applier  200  includes steps of loading in a plurality of spring clips  100  into clip carrier  216  such that the wire loops  102 ,  104  are received within channels with the clips thus held in an open position by rails  220 ,  222 . Then, each time that trigger  256  is compressed, each clip  100  is advanced forward in clip carrier  216 . Clips  100  are arranged in clip carrier  216  head to tail with a small space between adjacent clips so that the clips are pushed through clip carrier  216  by prongs  214  of pusher rod  212 .  
         [0053]     During this procedure rotation of spring clip  100  is prevented by containing wire loops  102 ,  104  in the partially closed channels of clip carrier  216 .  
         [0054]     In summary, compression members  208 ,  210  are substantially parallel and are fixedly attached to the applier at slidable pins  234 ,  236 . Slidable pins  234 ,  236  engage clip magazine  216  in slot  238 . Magazine  216  is fixedly attached to the handle of the applier. Tubular shaft  206  is distally movable during the trigger stroke. As tubular shaft  206  moves distally under the control of the trigger stroke, crimp features  258 ,  260  cause guide  262  to move distally. Protrusions  264 ,  266  move up ramps  244 ,  246  that are fixedly attached to upper and lower compression members  208 ,  210 . This force has a downward component that compresses spring  240  and moves upper and lower compression members  208 ,  210  toward each other, compressing tissue therebetween. Pins  234 ,  236  ride in slot  238  keeping upper and lower compression members  208 ,  210  registered with each other and substantially parallel, as shown in  FIGS. 8B and 9B . In the second part of the trigger stroke, the spring clip, which has control features mating with rails  220 ,  222 , rides up onto pins  234 ,  236  and onto upper and lower compression members  208 ,  210 . Ejection and tissue ligation then occurs.  
         [0055]     With this invention there is thus no jaw pivot to damage tissue. In addition, since the compression members are substantially parallel to one another, visibility is enhanced.  
         [0056]     It will be appreciated by those skilled in the art that the embodiment described above is only exemplary and that the clip applier of the present invention may be modified without going beyond the scope of the present invention. For example, although two springs are shown on each side of the proximal end of the compression members, a single spring or other mechanical equivalents may be used to bias the compression members if it is desired that the compression members be biased relative to one another. Movement of the upper and lower compression members toward one another may be accomplished in other ways such as with a vertical turn screw and gear arrangement. The compression members may be directly attached to the shaft of the clip applier rather than the clip carrier as would be appreciated by those skilled in the art.  
         [0057]     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.