Abstract:
An occlusion clamp comprising: (a) an occlusion tongs including a primary spring coupling a first longitudinal arm to a second longitudinal arm, the first longitudinal arm including a first linear occlusion surface configured to be parallel to and overlap a second linear occlusion surface of the second longitudinal arm, each of the first and second longitudinal arms having a free distal end; and, (b) a secondary spring removably coupled to the occlusion tongs.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/729,023, filed Nov. 21, 2012 and titled, “OCCLUSION CLIP,” the disclosure of which is hereby incorporated by reference. 
     
    
     RELATED ART 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure is directed to devices used to occlude anatomical structures and, more specifically, to clips that may be used to occlude anatomical structures. 
         [0004]    2. Brief Discussion of Related Art 
         [0005]    Embolic stroke is the nation&#39;s third leading killer for adults, and is a major cause of disability. There are over 700,000 strokes per year in the United States alone. Of these, roughly 100,000 are hemorrhagic, and 600,000 are ischemic (either due to vessel narrowing or to embolism). The most common cause of embolic stroke emanating from the heart is thrombus formation due to atrial fibrillation. Approximately 80,000 strokes per year are attributable to atrial fibrillation. Atrial fibrillation is an arrhythmia of the heart that results in a rapid and chaotic heartbeat that produces lower cardiac output and irregular and turbulent blood flow in the vascular system. There are over five million people worldwide with atrial fibrillation, with about four hundred thousand new cases reported each year. A patient with atrial fibrillation typically has a decreased quality of life due, in part, to the fear of a stroke, and the pharmaceutical regimen commonly used to reduce that risk. 
         [0006]    For patients who develop atrial thrombus from atrial fibrillation, the clot normally occurs in the left atrial appendage (LAA) of the heart. The LAA is a cavity that looks like a small pocket or windsock that is connected to the lateral wall of the left atrium between the mitral valve and the root of the left pulmonary vein. The LAA normally contracts with the rest of the left atrium during a normal heart cycle, thus keeping blood from becoming stagnant therein, but often fails to contract with any vigor in patients experiencing atrial fibrillation due to the discoordinate electrical signals associated with atrial fibrillation. As a result, thrombus formation is predisposed to form in the stagnant blood within the LAA. 
         [0007]    Blackshear and Odell reported that of 1288 patients with non-rheumatic atrial fibrillation involved in their study, 221 (17%) had thrombus detected in the left atrium. Blackshear J L, Odell J A.,  Appendage Obliteration to Reduce Stroke in Cardiac Surgical Patients With Atrial Fibrillation . Ann Thorac. Surg., 1996. 61(2):755-9. Of the patients with atrial thrombus, 201 (91%) had the atrial thrombus located within the left atrial appendage. The foregoing suggests that the elimination or containment of thrombus formed within the LAA of patients with atrial fibrillation would significantly reduce the incidence of stroke. 
         [0008]    Pharmacological therapies for stroke prevention, such as oral or systemic administration of warfarin, may be inadequate due to serious side effects of the medications and lack of patient compliance in taking the medication. 
         [0009]    One approach to LAA exclusion is occlusion of the LAA using a permanent clip. Prior art clips have not been permanently attached to the base of the LAA and operate to close off the interior pocket from the atrium. Over time, scar tissue seals the LAA at the point where the tissue is sandwiched between the clip, while scar tissue attempts to grow around the clip to maintain it in position. Prior art clips have been closed ended so that application of the clip to the LAA is more complicated because it requires feeding the LAA in between opposed spring arms, while concurrently feeding the LAA in between biased straight bars. 
         [0010]    Despite the various efforts in the prior art, there remains a need for a minimally invasive methods and associated devices for occlusion of the LAA that allow the clip to be placed from the side of the LAA without having to feed the LAA in between a completely bounded perimeter. 
       INTRODUCTION TO THE INVENTION 
       [0011]    It is a first aspect of the present invention to provide an occlusion clamp comprising: (a) an occlusion tongs including a primary spring coupling a first longitudinal arm to a second longitudinal arm, the first longitudinal arm including a first linear occlusion surface configured to be parallel to and overlap a second linear occlusion surface of the second longitudinal arm, each of the first and second longitudinal arms having a free distal end, and (b) a secondary spring removably coupled to the occlusion tongs. 
         [0012]    In a more detailed embodiment of the first aspect, the first longitudinal arm, the spring, and the second longitudinal arm are integrated. In yet another more detailed embodiment, the first longitudinal arm includes a first trench extending longitudinally along a majority of a length of the first longitudinal arm, the second longitudinal arm includes a second trench extending longitudinally along a majority of a length of the second longitudinal arm, at least a first portion of the secondary spring is configured engage the first trench to removably couple the secondary spring to the occlusion tongs, and at least a second portion of the secondary spring is configured to engage the second trench to removably couple the secondary spring to the occlusion tongs. In a further detailed embodiment, the first trench includes a first plurality of cavities and each configured to potentially receive the first portion of the secondary spring to maintain a relative position of the secondary spring with respect to the first longitudinal arm. In still a further detailed embodiment, the second trench includes a second plurality of cavities and each configured to potentially receive the second portion of the secondary spring to maintain a relative position of the secondary spring with respect to the second longitudinal arm. In a more detailed embodiment, the first plurality of cavities is spaced apart from one another. In a more detailed embodiment, the first plurality of cavities is spaced apart from one another and the second plurality of cavities is spaced apart from one another. In another more detailed embodiment, the first longitudinal arm includes a first projection extending longitudinally along a majority of a length of the first longitudinal arm, the second longitudinal arm includes a second projection extending longitudinally along a majority of a length of the second longitudinal arm, at least a first portion of the secondary spring is configured to engage the first projection to removably couple the secondary spring to the occlusion tongs, and at least a second portion of the secondary spring is configured to engage the second projection to removably couple the secondary spring to the occlusion tongs. In yet another more detailed embodiment, the first projection comprises a first plurality of projections and each configured to potentially engage the first portion of the secondary spring to maintain a relative position of the secondary spring with respect to the first longitudinal arm. In still another more detailed embodiment, the second projection comprises a second plurality of projections and each configured to potentially engage the second portion of the secondary spring to maintain a relative position of the secondary spring with respect to the second longitudinal arm. 
         [0013]    In yet another more detailed embodiment of the first aspect, the first plurality of projections is spaced apart from one another. In yet another more detailed embodiment, the first plurality of projections is spaced apart from one another and the second plurality of projections is spaced apart from one another. In a further detailed embodiment, the first longitudinal arm includes at least one of a first cavity and a first projection extending longitudinally along a majority of a length of the first longitudinal arm, the second longitudinal arm includes at least one of a second cavity and a second projection extending longitudinally along a majority of a length of the second longitudinal arm, at least a first portion of the secondary spring is configured to engage at least one of the first cavity and the first projection to removably couple the secondary spring to the occlusion tongs, and at least a second portion of the secondary spring is configured to engage at least one of the second cavity and the second projection to removably couple the secondary spring to the occlusion tongs. In still a further detailed embodiment, the first projection comprises a first plurality of projections and each configured to potentially engage the first portion of the secondary spring to maintain a relative position of the secondary spring with respect to the first longitudinal arm, and the second projection comprises a second plurality of projections and each configured to potentially engage the second portion of the secondary spring to maintain a relative position of the secondary spring with respect to the second longitudinal arm. In a more detailed embodiment, the first plurality of projections is spaced apart from one another, and the second plurality of projections is spaced apart from one another. In a more detailed embodiment, the first cavity comprises a first plurality of cavities and each configured to potentially engage the first portion of the secondary spring to maintain a relative position of the secondary spring with respect to the first longitudinal arm, and the second cavity comprises a second plurality of cavities and each configured to potentially engage the second portion of the secondary spring to maintain a relative position of the secondary spring with respect to the second longitudinal arm. In another more detailed embodiment, the first plurality of cavities is spaced apart from one another, and the second plurality of cavities is spaced apart from one another. In yet another more detailed embodiment, the spring comprises a discontinuous ring having a first end and a second end, the first end is spaced apart from the second end, the first end is mounted to the first longitudinal arm, and the second end is mounted to the second longitudinal arm. In still another more detailed embodiment, the first end includes a first planar surface, the second end includes a second planar surface, and the first planar surface extends parallel to the second planar surface. 
         [0014]    In a more detailed embodiment of the first aspect, the first longitudinal arm includes a first arcuate boundary defining a first arcuate depression, the second longitudinal arm includes a second arcuate boundary defining a second arcuate depression, and the primary spring interposes the first arcuate boundary and the second arcuate boundary. In yet another more detailed embodiment, the first longitudinal arm, the primary spring, and the second longitudinal arm are fabricated from at least one of a polymer, a composite, concrete, a metal, wood, and a ceramic, the secondary spring is fabricated from at least one of a polymer, a composite, concrete, a metal, wood, and a ceramic. In a further detailed embodiment, the first longitudinal arm, the primary spring, and the second longitudinal arm are fabricated from a polymer, and the secondary spring is fabricated from a metal. In still a further detailed embodiment, the first longitudinal arm, the primary spring, and the second longitudinal arm are fabricated from the same polymer. In a more detailed embodiment, the secondary spring includes a U-shape. In a more detailed embodiment, the secondary spring includes a longitudinal cross section comprising at least one of circular, rectangular, triangular, and oblong. In another more detailed embodiment, the secondary spring comprises a discontinuous loop having a first closed end and a second open end, the second open end being partially defined by a pair of spaced apart legs each having an arcuate projection. 
         [0015]    It is a second aspect of the present invention to provide an occlusion clamp comprising: (a) a first jaw including a first occlusion surface; (b) a second jaw repositionably mounted to the first jaw, the second jaw including a second occlusion surface; (c) a primary spring removably coupled to the first jaw and the second jaw to exert a first bias acting on proximal ends of the first and second jaws; and, (d) a secondary spring removably coupled to the first jaw and the second jaw to exert a second bias acting on distal ends of the first and second jaws. 
         [0016]    In a more detailed embodiment of the second aspect, the second jaw is configured to be pivotally and radially repositionably mounted to the first jaw. In yet another more detailed embodiment, the occlusion clamp further includes a pin mounted to the second jaw, wherein the first jaw includes an orifice sized to allow at least partial throughput of the pin and radial movement of the pin within a boundary of the orifice. In a further detailed embodiment, at least a portion of the pin includes a circular cross-section, and the second jaw includes a cavity configured to receive a projection of the pin in a friction fit to mount the pint to the second jaw. In still a further detailed embodiment, at least a portion of the pin includes a circular cross-section, and the second jaw includes a projection configured to be received by a cavity of the pin to mount the pin to the second jaw via a friction fit. In a more detailed embodiment, the first jaw includes a first elongated platform having a dominant lengthwise dimension, and the second jaw includes a second elongated platform having a dominant lengthwise dimension and configured to vertically overlap the first elongated platform. In a more detailed embodiment, the first jaw includes a first hub extending from the first elongated platform in the lengthwise dimension, the first hub having a widthwise dimension perpendicular to the lengthwise dimension that is less than a widthwise dimension of the first elongated platform, the first hub includes a height dimension perpendicular to the lengthwise dimension and the widthwise dimension, the height dimension of the first hub being greater than a height dimension of the first elongated platform, the second jaw includes a second hub extending from the second elongated platform in the lengthwise dimension, the second hub having a widthwise dimension perpendicular to the lengthwise dimension that is less than a widthwise dimension of the second elongated platform, and the second hub includes a height dimension perpendicular to the lengthwise dimension and the widthwise dimension, the height dimension of the second hub being greater than a height dimension of the second elongated platform. In another more detailed embodiment, the first jaw includes a first hub extending from the first elongated platform, the second jaw includes a second hub extending from the second elongated platform, and the first hub is configured to horizontally overlap the second hub. In yet another more detailed embodiment, the first jaw includes a first elongated platform and a first hub, the second jaw includes a second elongated platform and a second hub, the first hub includes a cavity sized to house the primary spring, and the primary spring is concurrently mounted to the first hub and at least one of the second hub and the pin. In still another more detailed embodiment, the primary spring includes a U-shaped portion. 
         [0017]    In yet another more detailed embodiment of the second aspect, the primary spring comprises a discontinuous loop. In yet another more detailed embodiment, the primary spring comprises a continuous loop. In a further detailed embodiment, the primary spring is fabricated from at least one of a polymer, a composite, and a metal. In still a further detailed embodiment, the primary spring is configured to exert a first bias to retard radial repositioning between the first jaw and the second jaw, and the secondary spring is configured to exert a second bias to retard pivotal repositioning between the first jaw and the second jaw. In a more detailed embodiment, the secondary spring includes a U-shaped portion. In a more detailed embodiment, the secondary spring comprises a discontinuous loop. In another more detailed embodiment, the first jaw includes a first trench, the second jaw includes a second trench, and the secondary spring is configured to be received concurrently with the first trench and the second trench when coupled to the first jaw and the second jaw. In yet another more detailed embodiment, the first jaw includes a first projection, the second jaw includes a second projection, and the secondary spring is configured to concurrently receive the first projection and the second projection when coupled to the first jaw and the second jaw. In still another more detailed embodiment, the first jaw includes a substantially planar first occlusion surface, the second jaw includes a substantially planar second occlusion surface, a lengthwise dimension of the first occlusion surface is larger than a widthwise dimension perpendicular to the lengthwise dimension, a lengthwise dimension of the second occlusion surface is larger than a widthwise dimension perpendicular to the lengthwise dimension. In a more detailed embodiment of the third aspect, the secondary spring is fabricated from at least one of a polymer, a composite, and a metal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is an elevated perspective view of a first exemplary occlusion clip in accordance with the instant disclosure. 
           [0019]      FIG. 2  is a perspective view of the exemplary embodiment of  FIG. 1 . 
           [0020]      FIG. 3  is a profile view of the exemplary embodiment of  FIG. 1 . 
           [0021]      FIG. 4  is a cross-sectional view of the exemplary tongs part of the exemplary embodiment of  FIG. 1 . 
           [0022]      FIG. 5  is an elevated perspective view from a left side of the exemplary primary spring of the exemplary embodiment of  FIG. 1 . 
           [0023]      FIG. 6  is an elevated perspective view from a right side of the exemplary primary spring of the exemplary embodiment of  FIG. 1 . 
           [0024]      FIG. 7  is an elevated perspective view of an exemplary spring in accordance with the first and second exemplary embodiments. 
           [0025]      FIG. 8  is a profile view of the exemplary spring of  FIG. 7 . 
           [0026]      FIG. 9  is an elevated perspective view from the front of a second exemplary occlusion clip in accordance with the instant disclosure. 
           [0027]      FIG. 10  is a profile view from the front of the second exemplary occlusion clip of  FIG. 9 . 
           [0028]      FIG. 11  is an elevated perspective view from the rear of the second exemplary occlusion clip of  FIG. 9 . 
           [0029]      FIG. 12  is an elevated perspective view from the front of a first jaw of the second exemplary occlusion clip of  FIG. 9 . 
           [0030]      FIG. 13  is an elevated perspective view from the rear of the first jaw of the second exemplary occlusion clip of  FIG. 9 , shown with a first secondary spring and pin mounted to the first jaw. 
           [0031]      FIG. 14  is an elevated perspective view from the rear of the first jaw of the second exemplary occlusion clip of  FIG. 9 . 
           [0032]      FIG. 15  is a bottom view of the first jaw of the second exemplary occlusion clip of  FIG. 9 . 
           [0033]      FIG. 16  is a bottom perspective view from the front of a second jaw of the second exemplary occlusion clip of  FIG. 9 . 
           [0034]      FIG. 17  is an elevated perspective view from the front of the second jaw of the second exemplary occlusion clip of  FIG. 9 . 
           [0035]      FIG. 18  is an elevated perspective view from the left of an alternate first jaw that may be used in lieu of the first jaw with the occlusion clip of  FIG. 9 , shown with an alternate first secondary spring and pin mounted to the alternate first jaw. 
           [0036]      FIG. 19  is a bottom perspective view from the left of the alternate first jaw of  FIG. 18 . 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    The exemplary embodiments of the present disclosure are described and illustrated below to encompass devices, methods, and techniques for fabricating, operation of, and implanting an occlusion clip. Of course, it will be apparent to those of ordinary skill in the art that the embodiments discussed below are exemplary in nature and may be reconfigured without departing from the scope and spirit of the present disclosure. However, for clarity and precision, the exemplary embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present disclosure. Accordingly, it should be understood that the following detailed description of embodiments of the present disclosure are exemplary in nature and are not intended to constitute limitations upon the present invention. It is also to be understood that variations of the exemplary embodiments contemplated by one of ordinary skill in the art shall concurrently fall within the scope and spirit of the invention. 
         [0038]    Referencing  FIGS. 1-8 , a first exemplary occlusion clip  100  includes tongs  110  that are repositionable with respect to a secondary spring  120 . In this exemplary embodiment, the tongs  110  may be fabricated from various materials such as, without limitation, a biologic material, a biologically reabsorbable material, a plastic, a metal, a metal alloy, and carbon fiber. In further exemplary form, the material may be formulated, include additives, or naturally be reabsorbable by a mammalian body within a predetermined period of time, such as six months or longer. 
         [0039]    The secondary spring  120  may be fabricated from various such as, without limitation, a biologic material, a biologically reabsorbable material, a plastic, a metal, a metal alloy, and carbon fiber. 
         [0040]    In exemplary form, the tongs  110  include a first longitudinal segment  130  that is mounted to a second longitudinal segment  132  by way of a primary spring  134 . The primary spring  134  operates to bias a proximal portion of both the first and second longitudinal segments  130 ,  132  toward one another, while a distal portion of both the first and second longitudinal segments are biased toward one another using the secondary spring  120 . In this exemplary embodiment, each longitudinal segment  130 ,  132  is a mirror image of the other and comprises a generally linear arm extending from the primary spring  134 . But it should also be noted that the longitudinal segments need not be mirror images of one another. 
         [0041]    A first exterior surface  140  of the longitudinal segments  130 ,  132  is substantially convex and includes a semicircular cross-section perpendicular to the longitudinal length thereof. This first surface seamlessly transitions into a pair of lateral surfaces  142 ,  144  that extend substantially parallel to one another and spaced apart from one another the width of the segment. Each lateral surface  142 ,  144  terminates at a respective rounded edge  146 ,  148  that transitions into a concave interior surface  150 . The concave interior surface  150  has a substantially uniform, semicircular cross-section perpendicular to the longitudinal length thereof and provides a linear, longitudinal channel  152  within which a portion of the secondary spring  120  traverses. The three exterior surfaces  140 ,  142 ,  144  and the interior surface  150  longitudinally converge at a distal end  154  that is substantially planar and perpendicular with respect to the exterior surfaces and interior surface, but for a rounded transition  156  linking the surfaces to one another. 
         [0042]    Opposite the distal ends  154  of the longitudinal segments  130 ,  132  is the primary loop spring  134 . In this exemplary embodiment, the primary spring  134  is integrally formed with the longitudinal segments  130 ,  132  and, in this fashion, provides a seamless transition therebetween. The primary spring  134  includes a central discontinuous loop  160  having an outer circumferential surface  162  with a substantially constant outer diameter until reaching a bottleneck  164 . This bottleneck  164  connects the discontinuous loop  160  to proximal arcuate housing segments  166 ,  168 , that themselves are coupled to the longitudinal segments  130 ,  132 . 
         [0043]    Referring back to the discontinuous loop  160 , lateral and medial ends of the circumferential surface  162  are rounded over to transition to a pair of parallel, spaced apart medial and lateral surfaces  170 ,  172 . An interior of the primary spring  134  is hollow and includes a through orifice extending in the medial-lateral direction. This orifice is partially bound by a pair of parallel, flat walls  176  that are connected at respective ends to an arcuate wall  178 . Opposite the arcuate wall  178  is a complementary arcuate wall comprising a first segment  182  spaced apart from a second segment  184  to delineate a slit  186  therebetween. In exemplary form, the slit  186  extends in the medial-lateral direction as well as the proximal-distal direction to provide separation between the housing segments  166 ,  168 . 
         [0044]    A proximal end of each housing segment  166 ,  168  is adjacent a partial opening  190  that extends in the medial-lateral direction and in the anterior-posterior direction (which is perpendicular to the medial-lateral direction and the proximal-distal direction). At the anterior and posterior ends of this opening  190  are a pair of spaced apart walls  194 ,  196  that delineate an arcuate groove  200  having a concave, U-shaped profile. A distal end of the arcuate groove  200  seamlessly transitions into the longitudinal channel  152 . As will be discussed in more detail hereafter, the arcuate groove  200  and longitudinal channel  152  are adapted to receive a portion of the secondary spring  120 . Interposing the housing segments  166 ,  168  and the longitudinal segments  130 ,  132  is a transition area  210  that maintains the cross-section of the longitudinal channel  152  and also increases an anterior-posterior height to reach the substantially constant anterior-posterior height of the longitudinal segments. In this exemplary embodiment, the transition area  210  includes an arcuate profile where the anterior-posterior height gradually increases to match that of the longitudinal segment attached thereto. As a result, the transition area  210  and the housing segments  166 ,  168  cooperate to define an internal cavity within which the primary spring  134  is positioned. 
         [0045]    Referring to  FIGS. 7 and 8 , an exemplary secondary spring  120  in accordance with the instant disclosure includes a circular cross-section that is generally perpendicular to the longitudinal length thereof, which is the dominant dimension of the secondary spring. While comprising an integrated structure, the secondary spring  120  can be characterized as including three sections, two of which are repeated. A first section  220  is generally U-shaped and includes a substantially constant radial arc to resemble a semi-circle. This first section  220  is integrally formed with a pair of second sections  222  at the distal ends of the first section and a proximal end of each second section. Each of the second sections  222  includes a substantially linear length that extends perpendicularly away from the first section and in parallel to one another and may be biased toward one another to achieve the desired compression force. A distal end of each second section  222  is mounted to a third section  224  that includes a sinusoidal shape. This sinusoidal shape is typified by a convex exterior surface  228  that operates to decrease an anterior-posterior gap  230  that is present along a longitudinal interior of the secondary spring. More specifically, the gap  230  between the second sections  222  is greater than the gap between the third sections  224 . As will be discussed in more detail hereafter, the third sections  224  are partially received within a depression formed into the longitudinal segments  130 ,  132  along a length of the longitudinal channel  152 . 
         [0046]    Referencing  FIGS. 1-3 , assembly and utilization of the exemplary occlusion clip  100  includes repositioning the tongs  110  so that tissue to be occluded is positioned between the exterior surfaces  140  of the longitudinal segments  130 ,  132 . In exemplary form, the tissue to be occluded may be a human left atrial appendage (not shown). 
         [0047]    By way of example, the tongs  110  is positioned so that the longitudinal segments  130 ,  132  are parallel and compressed against one another to allow the tongs to pass through a trocar. After passing through the trocar and into a mammalian chest cavity, a spacing between distal ends of the longitudinal segments  130 ,  132  is increased so that the spacing between the segments is large enough to accommodate a left atrial appendage of a heart. 
         [0048]    After the tissue in question, in this case the left atrial appendage, is positioned between the longitudinal segments  130 ,  132 , the longitudinal segments are moved closer to one another. This may be accomplished by manually compressing the longitudinal segments  130 ,  132  toward one another or by using the secondary spring  120  to move the longitudinal segments toward one another. For purposes of discussion, it will be presumed that that secondary spring  120  is utilized to compress the longitudinal segments  130 ,  132  toward one another. 
         [0049]    In order to use the secondary spring  120  to compress the longitudinal segments toward one another, the secondary spring is inserted through the trocar and into alignment with the tongs, presuming this alignment is not already completed. More specifically, the third sections  224  of the secondary spring  120  are aligned with the proximal end of the tongs  110  so that each of the third sections is at least partially received within a corresponding arcuate groove  200 . At this time, the secondary spring  120  is repositioned in the distal direction with respect to the tongs  110  so that the convex exterior surface  228  contacts the surface delineating the arcuate groove  200 . Continued movement of the secondary spring  120  toward the distal end of the tongs  110  causes the third sections  224  to increase the gap  230  therebetween to accommodate the tongs. The resilient nature of the secondary spring  120 , resulting from an increase in the gap  230 , exerts a bias force that causes the longitudinal segments  130 ,  132  to be compressed toward one another. Even further movement of the secondary spring  120  toward the distal end of the tongs  110  causes the spacing between the longitudinal segments  130 ,  132  to decrease and compress the segments against the tissue in question, in this case the left atrial appendage. The further along the secondary spring moves distally with respect to the tongs  110 , the greater the moment that is exerted against the longitudinal members  130 ,  132  because the moment necessary to move the second sections  222  apart increases as one moves closer to the first section  220 . Eventually, movement of the secondary spring  120  toward the distal end of the tongs  110  reaches a point where both third sections  224  are received within secondary depressions  250  formed deeper into the longitudinal segments  130 ,  132  as part of the longitudinal channels  152 . 
         [0050]    It should be noted that while the exemplary embodiment includes a single secondary depression  250  for each of the longitudinal members  130 ,  132 , it is also within the scope of the disclosure to provide multiple secondary depressions longitudinally distributed along the longitudinal members in order to accommodate ranges of force balancing. Likewise, while the exemplary secondary spring  120  has been shown to include a pair of third sections  224 , one adapted to engage each longitudinal member  130 ,  132 , it is also within the scope of the disclosure to include multiple third sections in series and/or spaced apart from one another to engage one or more of the secondary depressions  250  of each longitudinal member. 
         [0051]    When the secondary depressions  250  receive the third sections  224  of the secondary spring  120 , the secondary spring  120  is relatively locked into a longitudinal friction fit with respect to the tongs  110 . Likewise, when the secondary depressions  250  receive the third sections  224  of the secondary spring  120 , a bias exerted upon the longitudinal segments  130 ,  132  is approximately equal along the longitudinal length thereof. This longitudinal bias is operate to occlude the tissue clamped between the longitudinal segments  130 ,  132  and is the cooperative product of the bias of the secondary spring  120  and the bias of the primary spring  134 . More specifically, the secondary spring  120  may be selected based upon the bias it exerts to match that of the primary spring  134 . Conversely, the primary spring  134  may be designed to include a bias that matches that of a predetermined secondary spring  120 . 
         [0052]    Disassembly of the exemplary occlusion clip  100  includes repositioning the secondary spring  120  proximally with respect to the tongs  110  so that the third sections  224  become displaced from the depressions  250 . Eventually, continued proximal movement of the secondary spring  120  with respect to the tongs  110  results in the third sections  224  passing beyond the proximal most portion of the tongs, resulting in complete disengagement between the tongs and secondary spring. 
         [0053]    While the foregoing exemplary secondary spring  120  has been shown and described as having a uniform, circular cross-section along the longitudinal length thereof, it is also within the scope of this disclosure to provide differing cross-sections. By way of example, the cross-section of the secondary spring  120  may take on a rectangular shape having a dominant dimension that makes distortion in a first plane more difficult that distortion in a second plane, perpendicular to the first plane, typified by a subordinate dimension. Moreover, the cross-section of the secondary spring  120  may change along its longitudinal length. By way of example, a circular cross-section may be exhibited by a portion of the secondary spring, followed by a non-circular cross section (e.g., an oblong shape, rectangular shape, or otherwise). In other words, the cross-section along the length of the secondary spring may have a portion that is configured to retard motion or more readily allow motion in one or more directions, followed by or proceeded by a portion having a different cross-section that is configured to retard motion or more readily allow motion in one or more of the same or different directions. By way of further example, the U-shaped proximal first section  220  of the secondary spring  120  may have a circular cross-section, while the second sections  222  may have a rectangular profile with a dominant dimension in the lateral direction to allow greater deflection up or down rather than side to side. These different cross-sections may be useful to balance forces applied by the longitudinal segments  130 ,  132 . 
         [0054]    Referring to  FIGS. 7-17 , a second exemplary occlusion clip  300  includes a first jaw  310  repositionably mounted to a second jaw  312  and adapted to be biased toward one another using a secondary spring  314 . In this exemplary embodiment, the jaws  310 ,  312  are fabricated from a resilient or partially resilient material such as, without limitation, a biologic material, a biologically reabsorbable material, a plastic, a metal, a metal alloy, and carbon fiber. In further exemplary form, the material may be formulated, include additives, or naturally be reabsorbable by a mammalian body within a predetermined period of time, such as six months or longer. 
         [0055]    The spring  314  is also fabricated from a resilient material. Exemplary materials used to fabricate the spring  314  include, without limitation, a biologic material, a biologically reabsorbable material, a plastic, a metal, a metal alloy, and carbon fiber. 
         [0056]    Referring to  FIGS. 11-13 , the first jaw  310  includes an elongated platform  320  that extends from a hub  322 . The elongated platform  320  comprises an inclined occlusion surface  326  that is substantially planar but causes the height of the platform to gradually increase from a distal tip  328  to a proximal ending  334 . Opposite the inclined surface is a bottom surface  330  having formed therein a longitudinal trench  332  having a substantially rectangular cross-section that extends partially beyond the proximal ending  334 . It should be noted that the longitudinal trench  332  may have a cross-section other than rectangular including, without limitation, oblong and semicircular. The distal tip  328  interposes the inclined surface  326  and the bottom surface  330 , along with a pair of spaced apart, planar lateral surfaces  340 ,  342 . The planar lateral surfaces  340 ,  342  are each generally perpendicular to the inclined surface  326  and the bottom surface  330 . 
         [0057]    The hub  322  is located proximate the elongated platform  320  and is laterally inset with respect to one of the lateral surfaces  342 , but flush with respect to the other lateral surface  340 . A distal portion  350  of the hub  322  includes an arcuate profile from distal to proximal and rounds over at a proximal portion  352 . The distal and proximal portions  350 ,  352  include a peripheral flange  354  having a pair of parallel, linear segments  356 ,  358  extending into the interior of the hub  322 . Just above the first linear segment  356  is an oblong through opening  364  delineated by an oblong interior wall  366 . More specifically, the opening  364  extends through a wall having a pair of parallel, lateral surfaces  370 ,  372 . In particular, the first lateral surface  370  is co-planar with the lateral surface  340  of the elongated platform  320 . 
         [0058]    A primary spring  378  is received within the interior of the hub  322  and configured to provide bias for a proximal end of the exemplary occlusion clip  300 . More specifically, a cylindrical pin  380  extends through the oblong opening  364  and into the interior of the hub  322 , where a smaller diameter portion  382  of the cylindrical pin is adapted to be received within a through hole of the second jaw  312 . A lower portion of the cylindrical pin  380  is bounded by the first linear segment  356 , while an upper portion of the cylindrical pin is bounded by the primary spring  378 . In this manner, the cylindrical pin  380  is able to move vertically within the oblong opening  364 , but to do so the bias of the primary spring  378  must be overcome. In this exemplary embodiment, the primary spring  378  comprises a simple U-shaped configuration and where one of the ends of the spring is received between the linear segments  356 ,  358 , while the arcuate portion of the secondary spring abuts the peripheral flange  354 . In this manner, the primary spring  378  is relatively stationary, but may be deformed to allow the cylindrical pin  380  to vertically travel within the oblong opening  364 , thereby allowing a proximal spacing between the jaws  310 ,  312  to be changed. 
         [0059]    Referring to  FIGS. 16 and 17 , the second jaw  312  includes an elongated platform  420  that extends from a solid hub  422 . The elongated platform  420  comprises an inclined occlusion surface  426  that is substantially planar but causes the height of the platform to gradually increase from a distal tip  428  to a proximal ending  434 . Opposite the inclined surface is a bottom surface  430  having formed therein a longitudinal trench  432  having a substantially rectangular cross-section that extends partially beyond the proximal ending  434 . It should be noted that the longitudinal trench  432  may have a cross-section other than rectangular including, without limitation, oblong and semicircular. The distal tip  428  interposes the inclined surface  426  and the bottom surface  430 , along with a pair of spaced apart, planar lateral surfaces  440 ,  442 . The planar lateral surfaces  440 ,  442  are each generally perpendicular to the inclined surface  426  and the bottom surface  430 . 
         [0060]    The solid hub  422  comprises a pair parallel, spaced apart lateral surfaces  450 ,  452  that are bounded by an arcuate circumferential surface  454 . In this exemplary embodiment, the interior lateral surface  450  includes an orifice  460  (see  FIG. 11 ) that receives the smaller diameter portion  382  of the cylindrical pin  380  via a friction fit, thereby joining the jaws to one another. In this exemplary embodiment, the cylindrical pin  380  includes an oversized head  384  that provides a boundary for the first jaw  310  in order to allow the jaws  310 ,  312  to move with respect to one another, but inhibit lateral disengagement between the jaws where the jaws might otherwise come apart. 
         [0061]    In this exemplary embodiment, the secondary spring  314  includes generally the same structure and shape as the secondary spring  120  of the first exemplary embodiment, which is shown in  FIGS. 7 and 8 . Accordingly, description of the spring  314  has been omitted in this exemplary embodiment in furtherance of brevity. 
         [0062]    Referring back to  FIGS. 9-17 , assembly and utilization of the exemplary occlusion clip  300  includes repositioning the jaws  310 ,  312  so that tissue to be occluded is positioned between the inclined surfaces  326  of the elongated platforms  320 . In exemplary form, the tissue to be occluded may be a human left atrial appendage (not shown). 
         [0063]    By way of example, the jaws  310 ,  312  are positioned so that the inclined surfaces  326  of the elongated platforms  320  are parallel and compressed against one another to allow the jaws to pass through a trocar. After passing through the trocar and into a mammalian chest cavity, a spacing between the inclined surfaces  326  of the elongated platforms  320  is increased by overcoming the bias of the primary spring  378  in order to vertically reposition the second jaw  312  with respect to the first jaw  310  so that the pin  380  is against an uppermost portion of the oblong interior wall  366  so that the spacing therebetween is large enough to accommodate a left atrial appendage of a heart. 
         [0064]    After the tissue in question, in this case the left atrial appendage, is positioned between the inclined surfaces  326  of the elongated platforms  320 , the elongated platforms are allowed to move closer to one another, in part by discontinuing to overcome the bias of the primary spring  378 . In addition, additional bias is applied to the jaws  310 ,  312  by mounting the spring  314  to the jaws so the elongated platforms  320 ,  420  are compressed toward one another. 
         [0065]    In order to use the spring  314  to compress the inclined surfaces  326 ,  426  of the elongated platforms  320 ,  420  toward one another, the spring is first inserted through the trocar and into alignment with the jaws  310 ,  312 , presuming the spring is not already in alignment with the elongated platforms. More specifically, the third sections  224  of the spring  314  are aligned with the longitudinal trenches  332 ,  432  so that the third sections contact the hubs  322 ,  422  of both jaws  310 ,  312 . Further movement of the spring  314  in the distal direction with respect to the jaws  310 ,  312  causes the third sections  224  to increase the gap  230  therebetween to accommodate the jaws so that the third sections become seated within the longitudinal trenches  332 ,  432 . The resilient nature of the spring  314 , resulting from an increase in the gap  230 , exerts a bias force that causes the inclined surfaces  326 ,  426  of the elongated platforms  320 ,  420  to be compressed toward one another. Further movement of the spring  314  toward the distal ends  328 ,  428  of the elongated platforms  320 ,  420  causes the spacing between the inclined surfaces  326 ,  426  to decrease and compress the surfaces against the tissue in question, in this case the left atrial appendage. 
         [0066]    The further along the spring  314  moves distally with respect to the jaws  310 ,  312 , the greater the moment that is exerted against the inclined surfaces  326 ,  426  of the elongated platforms  320 ,  420  because the moment necessary to move the surfaces apart increases as one moves closer to the first section  220 . Eventually, movement of the spring  314  toward the distal end  328 ,  428  of the jaws  310 ,  312  reaches a point where continued distal movement of the spring is no longer possible. 
         [0067]    When the spring  314  reaches the point where further distal movement is no longer possible, the spring is locked into a longitudinal friction fit with respect to the jaws  310 ,  312 . Likewise, when the spring  314  reaches its distal most position, a moment exerted upon the jaws  310 ,  312  is approximately equal along the moment exerted upon a proximal portion of the jaws via the primary spring  378 . Accordingly, compression of the jaws  310 ,  312  is operative to occlude the tissue clamped between the generally parallel, inclined surfaces  326 ,  426  of the elongated platforms  320 ,  420 . 
         [0068]    In exemplary form, the jaws  310 ,  312  may be fabricated from any biologically compatible material including, without limitation, ceramics, polymers, metals, alloys of the foregoing, and composites. Likewise, the springs  314 ,  378  may be fabricated from any resilient material including, without limitation, polymers, metals, and alloy of the foregoing. 
         [0069]    In a preferred embodiment, the longitudinal trenches  332 ,  432  may include a series of depressions that are longitudinally spaced apart from one another and adapted to receive the convex exterior surface  228  of the third spring section  224 . In exemplary form, the locations of the depressions may be chosen to balance the moments between the spring  314  and the primary spring  378 . 
         [0070]    Disassembly of the exemplary occlusion clip  300  includes repositioning the spring  314  proximally with respect to the jaws  310 ,  312 . Eventually, continued proximal movement of the spring  314  with respect to the jaws  310 ,  312  results in the third sections  224  passing beyond the proximal most portion of the jaws, resulting in complete disengagement between the jaws and spring. 
         [0071]    Referring to  FIGS. 18 and 19 , an alternate exemplary first jaw  500  that may be used in place of the first jaw  310  as part of the second exemplary occlusion clip  300 . In this alternate exemplary first jaw  500 , the hub  502  is different from the hub  322  of the first jaw  310 . In particular, the revised hub  502  includes a peripheral flange  504  that cooperates with a lateral interior wall  506  to define an interior cavity  508 . Extending through the lateral interior wall  506  is an oblong through opening  512  configured to receive a cylindrical pin  380 . In this manner, the shape of the through opening  512  allows vertical travel of the cylindrical pin  380  with respect to the first jaw  500 . 
         [0072]    Proximate the bottom of the oblong opening  512  and extending from the interior wall  506  is a platform  516 . This platform  516  and the cylindrical pin  380  are concurrently circumscribed by an elastic band  520  that operates to exert a bias on the proximal aspects of the jaws  500 ,  312  when coupled to one another. By way of example, the resilient band  520  may be fabricated from any elastic material. In particular, the elastic band  520  resists vertical movement of the cylindrical pin  380  away from the platform. Vertical motion between the cylindrical pin  380  and the platform  516  causes the vertical spacing to change between the jaws  500 ,  312  at the proximal ends of the jaws. More specifically, a relatively larger vertical spacing between the cylindrical pin  380  and the platform  516  corresponds to a larger vertical spacing between proximal portions of the jaws  500 ,  312 , whereas a relatively smaller vertical spacing between the cylindrical pin and the platform corresponds to a smaller vertical spacing between proximal portions of the jaws. Accordingly, this jaw  500  provides an alternate configuration for using an elastic band  520 , as opposed to using the primary spring  378  and the first jaw  310 , in combination with the second jaw  312  to form an alternate exemplary occlusion clip. 
         [0073]    It is also within the scope of the invention for the exemplary occlusion clips to be shrouded in a tissue ingrowth material. For example, the exemplary occlusion clips may be encased in a C-shaped, loop sleeve that is cylindrical and closed at opposing ends in order to accommodate opening and closing of the exemplary clips (i.e., separation or spacing between the open ends sufficient to position tissue between portions of the clips). Those skilled in the art are familiar with tissue ingrowth materials such as porous fabrics, including Gore Dualmesh (available from W. L. Gore &amp; Associates, www.gore.com) that may be used as to shroud the foregoing exemplary embodiments. 
         [0074]    Following from the foregoing description, it should be apparent to those of ordinary skill in the art that, while the methods and apparatuses herein described constitute exemplary embodiments of the present invention, it is to be understood that the inventions described herein are not limited to the above precise embodiments and that changes may be made without departing from the scope of the invention as defined by the following claims. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclosed herein in order to fall within the scope of the claims, since inherent and/or unforeseen advantages of the present invention may exist even though they may not have been explicitly discussed herein.