Patent Publication Number: US-11660097-B2

Title: Clips and applicator for tissue closure

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation of and claims priority to U.S. patent application Ser. No. 14/930,595, entitled “Clips and Applicator for Tissue Closure,” which claims priority to U.S. Provisional Patent Application No. 62/074,212, filed Nov. 3, 2014, entitled “Bioabsorbable Clips and Applicator for Tissue Closure,” the entire disclosures of which are hereby incorporated by reference in their entirety. 
    
    
     This invention was made with government support under TR000128 awarded by the National Institutes of Health. The government has certain rights in the invention. 
    
    
     TECHNICAL FIELD 
     Embodiments herein relate to surgical clips and surgical clip applicators used in tissue closure. 
     BACKGROUND 
     The brain and spine are covered with a tough outer membrane called the dura mater, or dura. During surgical procedures, e.g., spinal surgery, the dura mater may be opened intentionally or inadvertently. Such an opening is called a durotomy or dural tear. Dural tears requiring closure or repair have been reported to occur in a significant percentage of surgical procedures. In some approaches, sutures are used to repair or close the dura. Durotomies must be closed prior to closing the skin. Failure of the closure can result in persistent cerebrospinal fluid (CSF) leakage, for example. This leakage may result in wound breakdown, spinal headaches, infection, meningitis, and other consequences. 
     Minimally invasive surgeries (MIS) are becoming more commonly used during surgical procedures, e.g., to treat a variety of pathologies including herniated discs, spinal stenosis, synovial cysts, spondylolisthesis, deformity, intradural tumors, etc. Such procedures use smaller incisions to decrease intraoperative blood loss, reduce tissue disruption, decrease postoperative pain, and decrease lengths of hospital stays, for example. 
     Minimally invasive surgeries make use of smaller ports and result in less tissue disruption than traditional procedures. However, should a durotomy occur using a minimally invasive surgery, closure of the dura can become extremely difficult or impossible due to the small size of the incision. For example, in the setting of minimally invasive spine surgery, the ability to close a durotomy may be compromised when suture material cannot be manipulated sufficiently to achieve tight closure. Thus, due to the physical limitations of small working areas, repair of a durotomy may be technically difficult and time-consuming when using conventional suture and knot-tying techniques. 
     In order to overcome these technical difficulties resulting from minimally invasive surgeries, metal staples, such as titanium staples, delivered via a suitable applicator may be crimped or bent from an open position into a closed position around the tissue edges to close a hole in a tissue such as a durotomy. However, in such approaches, it is necessary to place the staples sufficiently close together along a dura tear in order to close the tissue since such staples may be too thin to cover and hold significant lengths along the tissue break. Further, use of metal staples or clips either results in a permanent foreign body left in the tissue or a second surgical intervention to remove the staples or clips. Clips or staples left in the tissue may interfere with postoperative imaging resulting in undesirable artifacts in radiographic imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) scans. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings and the appended claims. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. 
         FIG.  1    shows an illustration of a surgical applicator applying example surgical clips to close a durotomy in accordance with various embodiments. 
         FIGS.  2 - 23    show scaled drawings of example surgical clips and example surgical clip applicators in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense. 
     Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order-dependent. 
     The description may use perspective-based descriptions such as up/down, back/front, and top/bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments. 
     The terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical contact with each other. “Coupled” may mean that two or more elements are in direct physical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other. 
     For the purposes of the description, a phrase in the form “A/B” or in the form “A and/or B” means (A), (B), or (A and B). For the purposes of the description, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). For the purposes of the description, a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element. 
     The description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous, and are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). 
     With respect to the use of any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     The present disclosure is directed to surgical clips and surgical applicators that may be used in performing rapid tissue closure in either minimally invasive surgeries or traditional open procedures. In particular, the surgical clips described herein are intended for use in closing durotomies, particularly durotomies resulting from minimally invasive surgeries. 
     A surgical applicator may be used to deliver the clips down a small opening, thereby obviating the need for sutures and knot tying to close the durotomy. An array of stacked surgical clips may be loaded into inwardly-turned tracks in a chamber or reservoir of the surgical applicator. A force may be applied to push a clip in the tracks towards a tip of the surgical applicator. The sides of that clip may be held within tracks at the tip of the applicator such that the mouth of the clip opens around the everted tissue edges of the dura, for example. Upon release of the clip from the applicator, the clip may grasp the everted edges, pulling the edges towards one another, closing the opening in the tissue. A force may again be applied to the next clip in the array so that the next clip is pushed into position to be opened at the mouth of the applicator for a subsequent application. 
     Disclosed herein is a surgical clip that includes opposing sides extending from a top portion. Each of the opposing sides may be convex. The opposing sides terminate at tips positioned below the top portion. The resting position of the clip is its closed position, and in the closed position, the tips are set at a first distance apart. Edges of the top portion and the first and second opposing sides form opposing front and back faces perpendicular to the first and second opposing sides. The front and back faces are angled inwardly towards each other at a region of the faces adjacent to the top portion. A first groove is formed in the first side. The first groove extends from the front face to the back face and has a top inner surface formed by a bottom surface of a region of the top portion extending over the first side. A second groove is formed in the second side. The second groove extends from the front face to the back face. The second groove has a top inner surface formed by a bottom surface of a region of the top portion extending over the second side. The first groove is substantially parallel to the second groove and the first and second grooves are substantially perpendicular to the front and back faces at a region of the front and back faces adjacent to the first and second tips. The first and second grooves are each configured to engage inwardly turned tracks at an end of a clip applicator such that, when a force is applied to the clip, the first and second sides bend outwardly away from each other, thereby increasing the distance between the tips to a second distance between the tips to place the clip in an open position. In the open position, the distance between the tips is greater than the distance between the tips in the closed position. In some embodiments, the width of the clip may be least 25% of the length of the clip (length is the dimension from the end of the first side to the end of the second side, while width is the dimension of the clip perpendicular to the length). In some embodiments, each tip may be made up of at least two tabs. Each tab may converge in a direction towards the opposing tip to form two opposing pairs of teeth. In some embodiments, the first and second grooves may be each configured to engage inwardly turned tracks at an end of a clip applicator such that when a push rod of the clip applicator is used to apply pressure to the top portion, the first and second sides bend outwardly away from each other, thereby increasing the distance between the tips to the second distance between the tips. In alternative embodiments, the first and second grooves may be each configured to engage inwardly turned tracks of a clip applicator, where a distance between the inwardly turned tracks decreases at an end of the clip applicator, such that when a force is applied to the back face of the clip, the clip moves within the tracks toward the end of the clip applicator thereby increasing the distance between the tips to the second distance between the tips. 
     Disclosed herein is an array of surgical clips. The array comprises two or more of the clips described above and a chamber housing the array of clips. The chamber has inwardly turned tracks engaging the grooves of each clip to maintain the front and back faces of each clip as orientated in the same direction as the front and back faces of the other clips in the plurality of surgical clips, yet large enough to allow movement of the plurality of clips in the direction of the faces of the clips. The clips in the array can also be in physical contact with one another. In some examples, a direction of the inwardly turned tracks may transition from a vertical direction to a horizontal direction in a transition region of the tracks and the angled regions of the faces of adjacent clips in the transition region may interface with each other. 
     Disclosed herein is a surgical clip applicator. The applicator includes a clip array within a chamber as described above and a pushing element configured to apply pressure to a top clip in the array. The applicator can also have a grating in a front wall or a back wall of the chamber. The grating may extend from the transition region of the tracks in a direction away from an open end of the chamber to hold the tracks in place and permit a user to view the clips in the applicator. 
     Since everted tissue edges are grasped by the surgical clip in such an approach, a risk of adhesion to the underlying spinal cord may be potentially reduced. Further, by applying a force to open such a surgical clip from a closed, resting state to an intermediate open state and then releasing the force to permit the clip to close to its resting state around the dural tissues, a greater amount of control may be conferred to the final closed state of the clip around the tissues to provide pressure on the dura leaflets for maintaining closure of the durotomy. 
     In this way, closure of the dura using a small bioabsorbable clip to grasp but not penetrate the tissue edges and maintain tension until the tissues heal may be applied quickly, easily, and in rapid succession by using an applicator. Such an approach may potentially increase speed and ease of clip application, decrease the risk of CSF leakage, decrease intradural adhesions due to non-penetration of the clip, reduce risk of adhesion to the underlying spinal cord, minimize dural exposure, and decrease expensive operative time. Further, such an approach may also be used in other surgical arenas where reapproximation is desired; including, for example, cranial surgery for closure of the dura, general surgery for closure of hollow organs, urologic surgery for closure of the bladder, closure of uereters and other tubular structures, and gynecological procedures for closure of reproductive structures. 
     The following description relates to bioabsorbable surgical clips and surgical applicators for performing rapid watertight tissue closure in minimally invasive or traditional open procedures. For example, as illustrated in  FIG.  1   , a surgical applicator  116  may be used to deliver one or more surgical clips, e.g., clips  118 , to assist in tissue closure. In  FIG.  1   , a dural tear or durotomy  108  is shown in the dura mater  104  around a spinal cord  106 . As remarked above, the dura mater is a tough outer membrane covering the brain and spinal cord which may be opened intentionally or inadvertently during surgical procedures. 
     The surgical clips may be composed of any material including any suitable bioabsorbable or resorbable material. The terms bioabsorbable and resorbable are used herein to mean dissolving inside the human body after a period of time. In some examples, the bioabsorbable material may be chosen based on a time duration at which the material dissolves. For example, the bioabsorbable material may have the property that it does not substantially dissolve within seven days after installation along the tissue but dissolves any time after one week while maintaining structural integrity before then. For example, the bioabsorbable material may comprise a biocompatible, bioabsorbable polymer such as Poly-L-Lactic Acid/Poly glycolic acid (PLLA/PGA), Polycapralactone, Polydioxanone or some combination thereof. By using a bioabsorbable material, no permanent foreign body is left in the tissue following surgery. Further in some examples, the clip may be composed of a material that is radiolucent, e.g., invisible or transparent to x-rays, as well as bioabsorbable. For example, the surgical clips may be composed of a suitable material which is radiolucent and bioabsorbable so that substantially no undesirable artifacts from the clips appear in radiographic imaging e.g., in magnetic resonance imaging (MRI) and computed tomography scans (CT). Further, by using a bioabsorbable and radiolucent material, surgical clips with a wide footprint may be used to cover a greater length along the tissue thereby potentially decreasing a number of clips needed to reliably seal the tissue in a water tight fashion. Additionally, in some examples, the clips may be composed of materials, e.g., polymers, selected to achieve a predetermined amount of strength, flexibility, and/or other mechanical properties of the clip. 
     As illustrated in  FIG.  1    at  124 , a surgical clip used to close a durotomy may comprise a first side  132  and a second side  130 , where the second side  130  opposes the first side  132 . The first and second opposing sides  132  and  130  extend from a top portion  128  of the clip and terminate at first and second tips positioned below the top portion  128 . For example, the first side  132  is coupled to and extends from top portion  128  and terminates at a first tip  134  positioned below the top portion  128 . Likewise, the second side  130  is coupled to and extends from top portion  128  and terminates at a second tip  136  positioned below the top portion  128 . In an installed, closed position, the tips  134  and  136  of the surgical clip may grasp but not penetrate or pierce everted tissue edges. For example, in  FIG.  1    surgical clip  114  is shown in an installed position along the durotomy  108  grasping everted tissue edges  112  and  110 . The surgical clips may include a variety of features and may have a variety of shapes and dimensions, examples of which are described below with reference to the scaled drawings of  FIGS.  2 - 23   . In some embodiments, the clip may have a length in a range from 3-5 millimeters (mm), a height in a range of 3-5 mm, a width in a range of 3-5 mm, and a diameter (if cylindrically shaped) in a range of 3-5 mm. In some examples, the top portion  128  of the clip may include an aperture  138 , slots, and/or other features used to achieve a particular bending moment of the surgical clip. For example, as described in more detail below, sides of the surgical clip may be temporarily bent outward by applying a force to the clip while holding the sides in place to install the clip over everted tissue edges. In some examples, a size of a slot or aperture or a thickness of the top portion of the clip may be selected so that the clip confers an optimal amount of force to grasp the tissue while maintaining the ability to be temporarily opened via engagement with tracks of the surgical applicator during an installation of the clip. For example, the clip may be designed to withstand at least 10 cmH 2 O pressure (e.g., prostrate pressure) without leakage and may, in some examples, be designed to withstand 20 cmH 2 O (e.g., standing lumbar pressure) without leakage. Further, the material selected may be based on a desired elasticity for applying a predetermined holding force to the tissue for a predetermined duration following installation of the clip around everted tissue edges. 
     The clip may include features that are configured to engage with the surgical applicator to assist in installation of the clip around edges of a tissue break. For example, the surgical clip may include grooves, cut-outs, notches, tabs or other suitable features that engage tracks or protrusions of the surgical applicator, e.g., which engage protrusions  122  and  123  of surgical applicator  116  shown in  FIG.  1   . The example clips shown in  FIG.  1    include tabs extending outwardly from the first and second sides of the clip. For example, a tab  140  is shown extending outwardly from first side  132  and may be configured to engage with protrusion  123  of the applicator  116  and tab  142  is shown extending outwardly from second side  130  and may be configured to engage protrusion  122  of the applicator. However, in other examples, such tabs may be omitted or other alternative engagement features may be included on the opposing sides of the clip, examples of which are shown in  FIGS.  2 - 23    described below. 
     As illustrated in  FIG.  1   , a stack of surgical clips  118  may be loaded into the surgical applicator  116  for quick successive delivery of surgical clips to grasp everted tissue edges, e.g., the bent and interfacing tissue edges  112  and  110 , to close the durotomy. For example, as shown in  FIG.  1   , an installed surgical clip  114  grasps but does not penetrate or pierce the everted edges of the dura thereby holding the edges together. Surgical applicator  116  may be used to deliver the clips down a small opening during minimally invasive procedures thereby potentially obviating the need for sutures and knot tying to close the dura. In one example approach, an array of stacked surgical clips  118  may be loaded into a chamber or reservoir of the surgical applicator and a downward force from a push rod or other pushing element in the chamber may be used to push the center of a clip located at a tip of the surgical applicator, e.g., clip  120  shown in  FIG.  1   , while the sides of that clip are firmly held at the tip causing the mouth of the clip to open around the everted tissue edges  110  and  112  of the dura. To release the clip, the push rod or pushing element may be retracted allowing the clip to grasp and reapproximate the two dural edges  110  and  112 . The push rod or pushing element can then retract further to engage the next clip in the reservoir so that the next clip is pushed into position to be opened at the mouth of the applicator for a subsequent application to the everted tissue edges. It should be understood that the use of a push rod to eject the clip is provided by way of illustration and any other suitable pusher or ejector feature may be included in the clip applicator. Further, the term “push rod” as used herein may refer to any such suitable pusher or ejector feature of the applicator used to deploy the clips. In alternative embodiments, examples of which are described below with regard to  FIGS.  2 - 23   , an array of clips may be loaded into inwardly turned tracks within a clip applicator and a force may be applied to a top clip in the array of clips to push the clips around a bend in the tracks. A distance between the tracks may decrease at an end of the applicator such that when a clip is pushed toward the end of the applicator within the tracks, the clip is forced into a temporary open position until it disengages with the tracks and returns to its closed, resting position. 
     The surgical clips have a closed resting configuration which can be substantially the same before and after installation along the tissue edges. During installation with the surgical applicator, the surgical clips have an intermediate open state formed by engagement of the clip with features of the surgical applicator during the installation of the clip. By applying a force to the clip while sides of the clip are engaged with features of the surgical applicator, a reversible deformation of the clip from a closed resting position to an intermediate open position may occur. This deformation is recoverable once the clip disengages with the engagement features of the applicator after the clip is positioned around the tissue edges so that the clip returns to its closed resting position to grasp the everted edges. 
       FIG.  1    shows an example clip in a closed resting state at  124  and in the intermediate open state at  126 . In the closed resting state there is a first distance  146  between the first and second tips  134  and  136 . In this closed position, the first distance may be selected so as to provide a sufficient amount of space between the tips  134  and  136  to accommodate a thickness of the everted tissue edges to which it is to be applied (e.g., enough space to accommodate twice the thickness of the dura) while maintaining sufficient gripping force on the everted tissue edges after application. The first side  132  and the second side  130  of the clip are configured to engage the clip applicator such that, when the clip applicator is used to apply a pressure to the clip, the first and second sides bend outwardly away from each other thereby increasing the distance between the tips to a second distance  148  greater than the first distance  146  so that the clip is temporarily deformed to an open position for installation around the tissue edges. In some examples, this second distance  148  may be a predetermined distance, e.g., at least 3 mm, achieved via forces applied to the clip from the clip applicator. 
     By applying a force to open such a surgical clip from a closed, resting state to an intermediate open state and then releasing the force to permit the clip to again close to its resting state around the dural tissues, a greater amount of control may be conferred to the final closed state of the clip around the tissues to provide an optimal pressure on the dura leaflets for maintaining closure. For example, the grasping force of the closed resting state of such a clip may be tailored to a specific type or thickness of tissue to which it is to be applied. 
       FIGS.  2 - 23    described below show scaled drawings of various example embodiments of surgical clips and surgical clip applicators. The example numerical dimensions shown in these figures are in millimeters (mm). Further, like-numbered elements used throughout the figures correspond to like elements. 
     Turning to  FIGS.  2 - 4   , a first example embodiment of a surgical applicator  116  and surgical clip  114  is shown from various perspectives and cross-sections. At  206 ,  208 ,  210 , and  212 , various viewpoints of the first example embodiment of a surgical clip  114  are shown. In particular, a front face view of example clip  114  is shown at  206 , a side view of clip  114  is shown at  208 , a bottom view of clip  114  is shown at  210 , and a perspective view of clip  114  is shown at  212 . 
     Clip  114  comprises a concave top portion  128  with opposing sides  130  and  132  extending therefrom. In particular, a first side  132  is coupled to top portion  128  via a rounded junction  251  and curves inwardly from junction  251  to a tip  134  positioned below top portion  128 . Likewise, a second side  130  is coupled to top portion  128  via a rounded junction  252  and curves inwardly from junction  252  to a tip  136  positioned below top portion  128 . A thickness of each tip of the opposing tips  136  and  134  tapers or decreases in a direction toward the opposing tip so that each tip of the opposing tips  136  and  134  converges in a direction towards the opposing tip. The concave top portion  128  curves toward the interior of the clip in the center of the top portion so that a minimum height of the clip occurs at the center of the top portion. The opposing sides  130  and  132  and the rounded junctions  251  and  252  coupling the sides  132  and  130  to the top portion form a heart-shaped face as seen in view  206 . 
     In this example, each of the first and second opposing sides  132  and  130  of the clip comprises a flat portion coupled via a curved top junction to the top portion  128 . For example, flat portion  249  is included in side  130  and flat portion  245  is included in side  132 . Flat portion  249  may be parallel with flat portion  245  when the clip is in the closed position. 
     Edges of the top portion  128  and the first and second opposing sides,  132  and  130 , form opposing front and back faces  271  and  273 , respectively, perpendicular to the first and second opposing sides. As shown at  208 , the front face  271  and back face  273  are angled inwardly towards each other at a region of the faces adjacent to the top portion  128 . In this example, the region  275  of the front face adjacent to the top portion  128  is inwardly angled by approximately 15 degrees relative to the region  276  of the front face adjacent to the first and second tips. Likewise, the region  277  of the back face adjacent to the top portion is inwardly angled by approximately 15 degrees relative to the region  278  of the back face adjacent to the first and second tips. 
     Each of the first and second tips  134  and  136  converges in a direction towards the opposing tip to form two opposing pairs of teeth. For example, tip  134  comprises a first tooth  260  and a second tooth  262  and tip  136  comprises a first tooth  259  and a second tooth  261 . Each tooth of a tip converges in thickness and width to an edge facing an opposing tooth on the other tip. For example, a width and thickness of tooth  260  on tip  134  decreases in a direction toward the opposing tooth  259  on tip  136  and a width and thickness of tooth  262  on tip  134  decreases in a direction toward the opposing tooth  261  on tip  136 . Teeth  259  and  261  on tip  136  likewise converge to the opposing teeth on tip  134  so that an aperture  263  is formed in the bottom of the clip between teeth of the tips. In some examples, this aperture  263  may have a circular shape with a predetermined diameter, e.g., a diameter of 2.5 mm. In alternative examples, as shown at  210 , aperture  263  may have a rounded rectangular shape. It should be understood that the aperture formed between the teeth of the tips on the bottom of the clip may have any suitable diameter or shape, e.g., oval-shaped, rectangular, diamond-shaped, etc. The teeth may be used to hold everted edges of tissue in place while not-penetrating and not piercing the tissue when repairing a durotomy, for example. One of skill in the art in light of this disclosure would understand how to make tips  134  and  136  of sufficient sharpness to grasp but not penetrate or pierce everted edges of a tissue such as a dura without undue experimentation. 
     Each of the first and second sides  132  and  130  includes a groove or notch configured to engage tracks in surgical applicator  116 . In particular, a first groove  291  is formed in the first side  132 . The first groove  291  extends from the front face  271  to the back face  273 . The first groove has a top inner surface  293  formed by a bottom surface of a region of the top portion  128  extending over the first side  132 . Likewise, a second groove  292  is formed in the second side  130 . The second groove  292  extends from the front face  271  to the back face  273 . The second groove  292  has a top inner surface  295  formed by a bottom surface of a region of the top portion extending over the second side  130 . The first groove  291  is substantially parallel to the second groove  292  and the first and second grooves are substantially perpendicular to the front and back faces at a region of the front and back faces adjacent to the first and second tips, e.g., regions  276  and  278 . 
     The first and second grooves,  291  and  292 , are each configured to engage inwardly turned tracks  296  and  297  of a clip applicator  116  such that, when a force is applied to the clip, the first and second sides bend outwardly away from each other, thereby increasing the distance between the tips to a second distance between the tips, wherein the second distance between the tips is greater than the first distance between the tips, thereby placing the clip in an open position. 
     The example clip  114  has a height  254  extending in a direction from a midpoint of the opposing tips  134  and  136  towards the top portion  128 , a length  253  extending in a direction from first side  132  towards second side  130 , and a width  299  extending from the front face  271  of the clip towards the back face  273  of the clip in a direction perpendicular to length  253 . In this example, the height  254  is less than the length  253  and the height is substantially the same as the width  299 . For example, the length may be approximately 5 mm and the height and width may both be approximately 3 mm; however, it should be understood that these dimensions are provided by way of example and are not intended to be limiting. Any suitable height, length, and width may be used. 
     The surgical clip  114  is shown in views  206 ,  208 ,  210 , and  212  in a closed resting position with a first distance  146  between opposing tips  134  and  136 . For example, this first distance  146  between the tips may be approximately 0.05 mm when the clip is in its resting closed state. A length of this first distance  146  may be based on a type and thickness of tissue to which it is to be applied. For example, the first distance  146  may be greater for applications on a thicker tissue. 
     Though not shown in  FIG.  2   , in some examples, the top portion  128  may be substantially flat when the clip is in the resting state (e.g., as shown in  FIG.  1   ), but may become concave or temporarily bent inward during a transitional intermediate open state of the clip during installation of the clip using clip applicator  116 . In particular, tracks  296  and  297  of clip applicator  116  may engage grooves  291  and  292  of clip  114  so that clip  114  is moveable within the tracks. A force may be applied to the clip to move the clip in the tracks towards the distal end  247  of the surgical applicator. In some examples, while the grooves are engaged with the tracks at the distal end  247 , a force may be applied to the top portion of the clip so that the distance between the tips of the clip increases to a second distance greater than the first distance  146 , e.g., greater than 0.05 mm, so that the tips of the clip are opened for installation of the clip around everted tissue edges. This second distance may be a distance of at least a predetermined amount, e.g., at least 3 mm. Alternatively, as described below, a force may be applied to the back face  273  of the clip to move the clip within the tracks towards the distal end  247  of the surgical applicator. In this example, a distance between the tracks may decrease at the distal end  247  of the applicator  116  so that when the clip is forced toward the distal end, the clip is at least partially placed into the open position. 
     Various views and cross-sections of an example surgical applicator are shown at  202 ,  204 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 , and  314  in  FIGS.  2 - 3   . In particular, at  202 , a perspective view of example surgical clip applicator  116  is shown. At  204 , a detailed view is shown of a distal end  247  of the applicator  116  in the region A shown in view  202 . The view  204  is shown at a scale of 4:1 relative to the view shown at  202 . At  308  a front view of applicator  116  is shown. At  310 , a cross-section of applicator  116  is shown along section B-B shown in view  308 . View  302  shows a detailed view of section C shown in view  310 , where view  302  is shown at a scale of 3:1 relative to view  310 . View  312  shows a side view of applicator  116 . View  314  shows a cross-sectional view along cross-section D-D in view  312 . View  306  shows a detailed view of region E shown in view  314  and is shown at a scale of 3:1 relative to view  314 . View  304  shows a perspective view of applicator  116 . 
     With reference to views  202 ,  204 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 , and  314  shown in  FIGS.  2 - 3   , the surgical applicator  116  comprises an elongated body  341  defining a chamber with an open end  247  within which a push rod  343  is contained. The push rod  343  extends away from the open end  247  of the surgical clip applicator and terminates at a thumb pusher element  350 . The thumb pusher element  350  comprises a curved handle shaped to fit a thumb of a user. The clip applicator further includes two opposing finger grasping elements  348  and  349  coupled to the elongated body  341 . For example, a user may grip the finger grasping elements  348  and  349  with two fingers and apply a downward force to the thumb pusher element  350  to urge the push rod downward toward the distal end  247  in order to apply a force to one or more clips in the chamber of the applicator. 
     Different sizes of the applicator may be available depending on a quantity of clips desired (e.g., an applicator may house 5-30 clips). For example, the applicator may come in different lengths depending on the type of surgery to be performed and the tissue on which the surgery will be performed. A short handle applicator may be used for open surgeries while a longer handle applicator may be used for deeper, smaller portals generated by minimally invasive surgical procedures. For example a height  342  of the applicator  116  may be in a range of 125-150 mm (˜5-6 inches) for minimally invasive procedures. The applicator may be used by right or left-handed neurosurgeons and may utilize activation mechanisms that are standard or familiar to neurosurgeons. For example, the activation mechanism of the applicator may utilize a pistol grip design, a syringe plunger-type design, a looped-end forcep design, etc. Further, the applicator may be activated by fingers of a user rather than whole-hand activation for increased dexterity and fine motor control. 
     An array or stack of surgical clips  318  is included within a chamber or reservoir within the walls of the elongated body  341  of the applicator. The chamber has inwardly turned rails or tracks  296  and  297  engaging the grooves of each clip to maintain the front and back faces of each clip as orientated in the same direction as the front and back faces of other clips in the plurality of surgical clips, yet large enough to allow movement of the plurality of clips in the direction of the faces of the clips. For example, the stack of surgical clips  318  may comprise two or more clips in physical contact with one another. A direction of the inwardly turned tracks transitions from a vertical direction to a horizontal direction in a bend or transition region  391  of the tracks. In the transition region  391 , the angled regions of the faces, e.g., angled regions  275  and  277  shown at  208 , of adjacent clips in the transition region interface with each other. For example, as shown at  302 , the angled portion of the back face of clip  331  physically touches the angled portion of the front face of adjacent clip  333  in the transition region  391 . The angled portions of the clips permit the clips to be stacked while they transition from a vertical to a horizontal direction around a bend or transition region of a surgical applicator. This allows the clips to be stacked but then dispensed individually and may accommodate flexure of the clips as a force is applied to dispense the clips. 
     In some examples, the array of stacked clips may be loaded into the chamber of the surgical applicator as a group rather than individually. For example, a user may obtain a package of a predetermined number of pre-stacked and pre-aligned surgical clips, e.g., including five or more individual clips stacked face to face with each other and oriented in the same direction, and may load this package of clips into the tracks of the surgical applicator, e.g., via an entry point comprising an opening at a top end of the applicator. As another example, an array of surgical clips may be preloaded into the applicator so that an end user receives a fully assembled pre-packaged applicator including a pre-loaded quantity of clips loaded within the chamber. Such a pre-packaged surgical clip applicator may have any suitable number of clips contained therein, e.g., 5, 10, 15, or 30 clips per applicator. The number of clips included in an applicator may depend on a particular surgical application. For example, the number of clips included in a clip array may depend on a particular surgical application or a length of the tissue tear to which the clips are to be applied. Such a pre-packaged, pre-loaded surgical clip applicator may be sterilized and suitably wrapped and, in some examples, may be disposable after use and may include labeling which indicates various parameters associated with the surgical applicator and clips therein such as dimensional information, disclaimer information, clip material composition, etc. 
     The array of stacked clips includes a top clip  337  which is in contact with a spring-loaded pusher element  381  in contact with the back face of top clip  337 . A spring  382  interfaces with pusher element  381  in the clip applicator to apply a continuous downward pressure to the stack of clips in the applicator. In particular, the spring-loaded pusher element  381  biases the stack of clips  318  toward the distal end  247  of the applicator  116 . 
     The array of stacked clips also includes a bottom clip  383  at the distal end  247  of applicator  116 . The front face of the bottom clip  383  interfaces with stopper elements  384  and  385 , which prevent the bottom clip from moving in a direction perpendicular to the front and back faces of the bottom clip towards the front face of the bottom clip. An end of the push rod  343  opposing the thumb pushing element  350  is in contact with the top portion of bottom clip  383 . The bottom clip  383  may be held in position via engagement of the grooves or notches in the sides of the clip with the opposing tracks or rails  297  and  296  at the distal end  247  of the applicator. 
     In this example embodiment, the push rod  343  interfaces with a top portion of bottom clip  383  via a clip interfacing element  345  coupled to an end of the push rod  343  opposing the thumb pusher element  350 . The clip interfacing element  345  may comprise a cylindrically-shaped element having a radius that complements the curvature of the concave top portion of the clip. Further, in this example, a spring  346  is included around a portion of the push rod between the thumb pusher element  350  and an inner wall feature within the chamber of the applicator. The spring  346  can comprise a wire spring encircling a portion of the push rod  343  which provides a biasing force to the push rod  343  in a direction away from the distal end  247  in order to return the push rod to an initial retracted position following an application of a downward force to the push rod via the thumb pushing element. However, in other examples, such a spring element may be omitted. 
     The surgical applicator  116  may also include grippers  371  at the distal end  247 . Grippers  371  may comprise two opposing arms which are biased away from each other but are held in a closed position around the sides of bottom clip  383  when opposing circular tabs  372  extending from push rod  343  interface with outer surfaces of the grippers. In particular the tabs  372  hold the grippers  371  together for an initial duration while a downward force is applied via push rod  343  to the top portion of bottom clip  383  to open the clip. After the initial duration wherein the clip  383  is opened, application of the downward force via the push rod to the top portion of bottom clip  383  may be continued so that the tabs  272  are pushed into opposing aperture or holes  373  formed in opposing sides of body  341 . The apertures  373  have diameters larger than the diameters of the circular tabs  372  so that when the tabs are moved into the apertures, constraint of the grippers by the tabs is released so that the opposing arms of the grippers move away from each other thereby releasing the clip from the distal end of the surgical applicator so that the open clip can be installed around everted tissues edges. 
     In some examples, a cover  340  may be included along a portion of at least one wall of the chamber of the surgical applicator. The cover  340  may comprise at least a portion of a wall of the applicator chamber perpendicular to side walls  338  and  339  of the chamber. In some examples, cover  340  may be composed of a transparent material. The cover may extend a distance along a wall of the chamber from above the tabs  372  toward the thumb pusher element to terminate at a location adjacent to spring  346 . Cover  340  may be removable and may be used to assist in assembly of the applicator. 
     In some examples, applicator  116  may also include a grating  393  in a wall of the chamber housing the clips. The grating may extend along the tracks  297  and  296  and may comprise a plurality of parallel trusses, ribs, or support members where each truss, rib, or support member spans from one track to the opposing track to provide support to the opposing tracks  296  and  297 . 
       FIG.  4    shows various viewpoints and cross-sections of an example surgical clip applicator system  402  which comprises a tubular retractor  497  within which clip applicator  116  may be inserted while performing a surgical procedure on dura  104 . At  406 , a top view of the surgical clip applicator system is shown. At  408 , a side view of the surgical clip applicator system is shown. At  412 , a detailed view of an end of the tubular retractor  497  is shown for the region F shown in view  408 . At  410 , a perspective view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle is shown. At  416 , a side view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle  490  is shown. View  414  shows a detailed view of the region G shown in view  416 . 
     Tubular retractor  497  may comprise a cylindrical body  483  defining an inner working aperture  481  extending from a top lip  480  to an open end  498  at the surgical site. The top lip extends around a circumference of the working aperture at a top open end of the tubular retractor  497  opposing the open end  498  and a circumference of the top lip may be greater than a circumference of the cylindrical body. For example, the inner working aperture may have a diameter of approximately 25 mm and may have a height  496  of approximately 80 mm so that applicator  116  can easily fit within the tubular retractor during a surgical procedure. 
     The tubular retractor  497  may further include a supporting element  482  coupled to the lip  480  at an end of the tubular retractor  497  opposing end  498 . For example, during a surgical procedure, the tubular retractor  497  may be positioned via supporting element  482  so that end  498  encompasses a surgical working area over the tissues to be repaired. In order to close the tissue using the clip applicator, the applicator  116  may be inserted into the tubular retractor  497  so that the distal end  247  of the applicator extends beyond end  498  of the tubular retractor  497  toward the tissue tear so that a surgical clip may be applied to everted tissue edges along the tear. 
     As shown in view  416  the applicator may be tilted away from a central axis of the tubular retractor  497  so that an angle  490  is formed between a central axis of the applicator and a central axis of the tubular retractor  497 , e.g., a 5° angle. In this way a clip may be applied using the applicator without obstructing the view of the surgeon applying the clips to the tissues. 
     Turning to  FIGS.  5 - 8   , another example embodiment of a surgical applicator  116  and surgical clip  114  are shown from various perspectives and cross-sections. At  506 ,  508 ,  510 , and  512  various viewpoints of the second example embodiment of a surgical clip  114  are shown. In particular, a front face view of an example clip  114  is shown at  506 , a side view of clip  114  is shown at  508 , a bottom view of clip  114  is shown at  510 , and a perspective view of clip  114  is shown at  512 . The top portion  128  of the surgical clip shown in  FIGS.  5 - 6    comprises two opposing wings,  581  and  582 , which extend over the opposing sides  132  and  130 . The grooves  291  and  292  are formed between top inner surfaces of the wings of the top portion and shelves  593  and  595  formed in each side. In particular, groove  291  has top inner surface  293  formed by a bottom surface of a region or wing  581  of the top portion  128  extending over the first side  132  and a bottom inner surface  593  formed as a top surface or shelf within side  132 . Likewise, groove  292  has top inner surface  295  formed by a bottom surface of a region or wing  582  of the top portion  128  extending over the second side  130  and a bottom inner surface  595  formed as a top surface or shelf within side  130 . In this example, the angle between the top inner surface  293  and the bottom inner surface  593  and the angle between the top inner surface  295  and the bottom inner surface  595  are both 60 degrees. However, in other examples, the angle between the top inner surfaces and the bottom inner surfaces of the grooves may be greater than 60 degrees or less than 60 degrees, e.g., 25 degrees. Further, when the clip is in the closed position, the bottom inner surface  593  may lie in the same plane as bottom inner surface  595 . 
       FIG.  6    shows additional embodiments of example surgical clips in the closed resting position in views  602 ,  604 ,  606 , and  608  and in an intermediate open position in views  610  and  612 . Additionally, in view  614  a stack of surgical clips  318  is shown. The stack of surgical clips comprises a top clip  337  having a back face  273  which is not in physical contact with another clip and a bottom clip  383  having a front face which is not in contact with another clip. In the stack  318 , the faces of adjacent clips may be in physical contact with each other and the stacking of the clips may accommodate a transition region  391  where the orientation of the clips transitions from a vertical direction to a horizontal direction. In the transition region  391 , the angled regions of the faces, e.g., angled regions  275  and  277  shown at  508 , of adjacent clips in the transition region interface with or physically touch each other. 
     Various views and cross-sections of example surgical applicator are shown at  502 ,  504 ,  702 ,  706 ,  708 ,  710 ,  712 , and  714  in  FIGS.  5  and  7   . In particular, at  502 , a perspective view of example surgical clip applicator  116  is shown. At  504 , a detailed view is shown of a distal end  247  of the applicator  116  in the region A shown in view  502 . The view  504  is shown at a scale of 4:1 relative to the view shown at  502 . At  708  a front view of applicator  116  is shown. At  710 , a cross-section of applicator  116  is shown along section B-B shown in view  708 . View  702  shows a detailed view of section C shown in view  710 , where view  702  is shown at a scale of 3:1 relative to view  710 . View  712  shows a side view of applicator  116 . View  714  shows a cross-sectional view along cross-section D-D in view  712 . View  706  shows a detailed view of region E shown in view  714  and is shown at a scale of 3:1 relative to view  714 . 
     The surgical applicator shown in  FIGS.  5  and  7    in similar to the applicator shown in  FIGS.  2 - 3    described above. However, in this example the clip interfacing element  345  comprises a wedge-shaped component which tapers in a direction toward distal end  247 . The clip interfacing element has a rounded end which can interface with the concave top portion  128  of the clip when a downward force is applied to push rod  343 . Further, in this example, a spring  346  is included around a portion of the push rod at a location adjacent to the clip interfacing element  345 . As remarked above, the spring  346  can comprise a wire spring encircling a portion of the push rod  343  which provides a biasing force to the push rod  343  in a direction away from the distal end  247  in order to return the push rod to an initial retracted position following an application of a downward force to the push rod via the thumb pushing element. However, in other examples, such a spring element may be omitted. 
     Additionally, in the example shown in  FIGS.  5  and  7   , the grippers  371  are held in a compressed position by opposing tabs  372  extending from the distal end of the push rod  343 . Each tab in the opposing tabs  372  extends through a cut-out or aperture, e.g., apertures  373 , in the arms of gripper  371  and is upwardly bent to interface with an outer surface of an arm of the gripper above the cutout to hold the grippers  371  in the compressed position so that the inwardly turned tracks hold the bottom clip  383  in place at the distal end  247  of the applicator. In particular, the tabs  372  hold the grippers  371  together for an initial duration while a downward force is applied via push rod  343  to the top portion of bottom clip  383  to open the clip. After the initial duration wherein the clip  383  is opened, application of the downward force via the push rod to the top portion of bottom clip  383  may be continued so that the tabs  272  are pushed into opposing apertures or cutouts  373  formed in opposing sides of body  341 . The apertures  373  are larger than the tabs  372  so that when the tabs are moved into the apertures, constraint of the grippers by the tabs is released so that the opposing arms of the grippers move away from each other thereby releasing the clip from the distal end of the surgical applicator so that the open clip can be installed around everted tissues edges. 
       FIG.  8    shows various viewpoints and cross-sections of another example surgical clip applicator system  402  which utilizes the clip applicator and clips shown in  FIGS.  5 - 7    described above. The embodiments shown in  FIG.  8    are similar to the embodiments shown in  FIG.  4    described above. In particular, at  806  a top view of the surgical clip applicator system is shown. At  808 , a side view of the surgical clip applicator system is shown. At  812 , a detailed view of an end of the tubular retractor  497  is shown for the region F shown in view  808 . At  810 , a perspective view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle is shown. At  816 , a side view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle  490  is shown. View  814  shows a detailed view of the region G shown in view  816 . 
     Turning to  FIGS.  9 - 10   , another example embodiment of a surgical applicator  116  and surgical clip  114  are shown from various perspectives and cross-sections. At  906 ,  908 ,  910 , and  912  various viewpoints of a surgical clip  114  are shown. In particular, a front face view of an example clip  114  is shown at  906 , a side view of clip  114  is shown at  908 , a bottom view of clip  114  is shown at  910 , and a perspective view of clip  114  is shown at  912 . The surgical clip shown in  FIG.  9    is similar to the surgical clip shown in  FIG.  5    described above. In particular, the top portion  128  of the surgical clip comprises two opposing wings,  581  and  582 , which are angled relative to each other and extend above and outward over the opposing sides  130  and  132 . Further, in this example, the angled regions  275  and  277  in the faces  271  and  273  are formed in a region of the faces above the shelves  593  and  595 . Additionally, in this non-limiting example, the concave top portion  128  is inwardly curved with a radius of 0.45 mm. 
     Various views and cross-sections of the surgical applicator are shown at  902 ,  904 ,  1002 ,  1006 ,  1008 ,  1010 ,  1012 , and  1014  in  FIGS.  9  and  10   . In particular, at  902 , a perspective view of example surgical clip applicator  116  is shown. At  904 , a detailed view is shown of a distal end  247  of the applicator  116  in the region A shown in view  902 . The view  904  is shown at a scale of 4:1 relative to the view shown at  902 . At  1008  a front view of applicator  116  is shown. At  1010 , a cross-section of applicator  116  is shown along section B-B shown in view  1008 . View  1002  shows a detailed view of section C shown in view  1010 , where view  1002  is shown at a scale of 3:1 relative to view  1010 . View  1012  shows a side view of applicator  116 . View  1014  shows a cross-sectional view along cross-section D-D in view  1012 . View  1006  shows a detailed view of region E shown in view  1014  and is shown at a scale of 3:1 relative to view  1014 . 
     The surgical applicator shown in  FIGS.  9  and  10    is similar to the applicator shown in  FIGS.  5  and  7    described above. However, in this example the opposing tabs  372  do not extend beyond the arms of grippers  371  but instead extend from a distal end of the push rod  343  to remain between the arms of the grippers in the interior of body  341 . In this example, the grippers are formed as an extension of body  341  and remain compressed around the bottom clip to hold the clip in position at the distal end  247  of the applicator. When a downward force is applied to the push rod  343 , the tabs interface with internal downwardly-angled shelves  991  and  993  to transfer outward forces to the arms of the grippers  371  so that the bottom clip is released from the inwardly turned tracks  296  and  297 . 
       FIG.  11    shows various viewpoints and cross-sections of another example surgical clip applicator system  402  which utilizes the clip applicator and clips shown in  FIGS.  9  and  10    described above.  FIG.  11    is similar to  FIGS.  4  and  8    described above. In particular, at  1106  a top view of the surgical clip applicator system is shown. At  1108 , a side view of the surgical clip applicator system is shown. At  1112 , a detailed view of an end of the tubular retractor  497  is shown for the region F shown in view  1108 . At  1110 , a perspective view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle is shown. At  1116 , a side view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle  490  is shown. View  1114  shows a detailed view of the region G shown in view  1116 . 
     Turning to  FIGS.  12 - 15   , other example embodiments of a surgical applicator  116  and surgical clip  114  are shown from various perspectives and cross-sections. At  1206 ,  1208 ,  1210 ,  1212 ,  1306 ,  1308 ,  1310 ,  1312 ,  1314 ,  1316 ,  1318 ,  1320 ,  1322 ,  1324 ,  1406 ,  1408 ,  1410 ,  1412 , and  1413  various viewpoints of example embodiments of a surgical clip  114  are shown. In particular, a front face view of an example clip  114  is shown at  1206 , a side view of clip  114  is shown at  1208 , a bottom view of clip  114  is shown at  1210 , and a perspective view of clip  114  is shown at  1212 . The surgical clip shown in  FIG.  12    is similar to the surgical clip shown in  FIG.  9    described above. However, in this example the wings  581  and  582  extend a non-zero distance beyond the sides  132  and  130  so that the length  253  of the top portion is greater than a length  1223  between the outer surface of side  132  and the outer surface of side  130 . Further, in this example, the angle between the top inner surface  293  and the bottom inner surface  593  and the angle between the top inner surface  295  and the bottom inner surface  595  are both 25 degrees. Additionally, the grooves  291  and  292  in the clip shown in  FIG.  12    include an inner flat region positioned between the top inner surface of the top portion, e.g.,  293  and  295 , and the shelves  593  and  595 . Further, in this example, the angled regions  275  and  277  in the faces  271  and  273  are formed in a region of the faces extending below the shelves  593  and  595 . 
     In some examples, as shown in  FIGS.  13  and  14   , each of the first and second tips  134  and  136  may converge to form staggered teeth. For example, tip  134  may converge in a direction towards tip  136  to form two teeth positioned adjacent to the two opposing faces and tip  136  may converge in a direction towards tip  134  to form a single tooth located between the two teeth formed by tip  134 . In views  1406 ,  1408 , and  1410  in  FIG.  14   , exemplary dimensions, angles, and tolerances of a surgical clip are shown in accordance with the disclosure. The dimensions shown in  FIG.  14    are in millimeters. 
     Various views and cross-sections of the fourth example surgical applicator are shown at  1216 ,  1218 ,  1220 ,  1502 ,  1504 ,  1506 ,  1508 ,  1510 , and  1520  in  FIGS.  12  and  15   . In some examples, the example surgical applicator shown in  FIGS.  12  and  15    may be attached adjacent to a distal end of an applicator body such as body  341  described in the examples above. In particular, the applicator shown in  FIGS.  12  and  15    may include additional components, such as push rods, chambers, biasing components, etc. not shown in  FIGS.  12  and  15   . Views  1216 ,  1218 , and  1220  show various perspective views of the example applicator. Views  1502 ,  1508 , and  1510  show side views of the applicator and views  1506 ,  1504 , and  1520  show front views of the applicator. 
     The surgical applicator shown in  FIGS.  12  and  15    includes a chamber  1505  housing a plurality of surgical clips. The chamber  1505  has inwardly turned tracks  296  and  297  for engaging the grooves of each clip to maintain the front and back faces of each clip as orientated in the same direction as the front and back faces of the other clips in the plurality of surgical clips, yet large enough to allow movement of the plurality of clips in the direction of the faces of the clips. A direction of the inwardly turned tracks transitions from a vertical direction to a horizontal direction in a transition region  391  of the tracks. In the transition region  391 , the angled regions of the faces of adjacent clips in the transition region interface with or touch each other. Additionally, a distance between the inwardly turned tracks decreases at an end of the applicator  247 . In this example, the applicator includes a grating  393  in a front wall of the chamber opposing the clip array. The grating  393  extends from the transition region of the tracks in a direction away from the open end of the chamber. 
       FIG.  16    shows various viewpoints and cross-sections of another example surgical clip applicator system  402  which utilizes the clip applicator and clips shown in  FIGS.  12 - 15    described above. In particular, at  1606  a top view of the surgical clip applicator system is shown. At  1608 , a side view of the surgical clip applicator system is shown. At  1612 , a detailed view of an end of the tubular retractor  497  is shown for the region F shown in view  1608 . At  1610 , a perspective view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle is shown. At  1616 , a side view of the surgical clip applicator system with the applicator inserted into the tubular retractor  497  at an angle  490  is shown. View  1614  shows a detailed view of the region G shown in view  1616 . 
       FIGS.  17 - 20    show another example clip applicator which is similar to the applicator shown in  FIGS.  12  and  15    described above. However, in this example, the applicator include a supporting element  1703  coupled between a bottom support member  1793  of the grating  393  and a front face  1791  of the applicator where the inwardly turned tracks,  296  and  297 , terminate at the distal end  247 . An aperture  1781  may be formed in the center of the supporting member  1703 . For example, a push rod may be inserted through the aperture  1781  so that a force can be applied to the top portion of the bottom clip to release the clip from the applicator. The supporting member may increase stability of the applicator. 
     Turning to  FIGS.  21 - 22   , other example embodiments of a surgical applicator  116  and surgical clip  114  are shown from various perspectives and cross-sections. The examples shown in  FIGS.  21 - 22    are similar to the examples shown in  FIG.  12    and  FIG.  17    described above. However, in this example, the transition region  391  has a greater radius to assist the movement of clips within the tracks around the transition region.  FIG.  23    shows various viewpoints and cross-sections of another example surgical clip applicator system  402  which utilizes the clip applicator and clips shown in  FIGS.  21  and  22    described above. 
     The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure. 
     Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope. Those with skill in the art will readily appreciate that embodiments may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments be limited only by the claims and the equivalents thereof.