Abstract:
The present invention relates to vascular clip made of biocompatible, non-metallic material that minimizes artifacts and obscuration of a diagnostic image developed using modalities such as CATSCAN, and MRI. The vascular clip is dimensionally comparable to metal clips, while maintaining sufficient clamping force to stop the flow of blood from an aneurysm, a subarachnoid hemorrhage or bleeding on the brain.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/612,766 filed on Mar. 19, 2012 and entitled ZERO ARTIFACT ANEURYSM CLIP which is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    A vascular clip made of biocompatible, non-metallic material that minimizes artifacts and obscuration of a diagnostic image developed using modalities such as CATSCAN, and MRI. The vascular clip is dimensionally comparable to metal clips, while maintaining sufficient clamping force to stop the flow of blood from an aneurysm, a subarachnoid hemorrhage or bleeding on the brain. 
       BACKGROUND 
       [0003]    Vascular surgical clips like hemostatic clips and aneurysm clips are often used in surgery to ligate vessels to stop the flow of blood. Surgical clips are also used to interrupt or occlude the oviduct or vas deferens in sterilization procedures. The clips are often left in place permanently and within a period of time the ligated end of the vessel will close, that is, hemostasis or occlusion will occur. 
         [0004]    Subarachnoid hemorrhage (SAH), or bleeding on the brain, is a significant and commonly encountered problem. Most cases of SAH are caused by leaking from arteries of the brain. There is a very high mortality and complication rate, with the vast majority of patients experiencing a medical complication which is potentially severe in approximately 40% of cases. Examples of such complications include strokes and re-bleeding, which leads to significant costs in ICU care and medical management. Approximately 1-5% of the United States population harbors brain aneurysms, and approximately 30,000 of these aneurysms rupture every year. 
         [0005]    Current treatments include endovascular coiling, which uses the femoral artery in the leg to thread up to a brain aneurysm to deploy coils to clot the aneurysm, or clip ligation, which involves an open brain surgery to manually place a clip of metallic material across the neck of the aneurysm. Metal clips are most commonly made from metals or alloys of titanium, elgiloy or stainless steel. The clip is typically formed from metallic wires that are formed into a torsional spring. The resulting clip has a normally closed position that is under spring preload. Using surgical tools, such as clip appliers that hold the torsional spring open to place the clip about the vessel, the jaws clamp the vessel and the nature of the spring loaded metal stays clamped resisting any force by the vessel to expand or open up. 
         [0006]    Major academic centers treat brain aneurysms with approximately a 50-50% split between clipping and coiling. Currently available clips are made of metals, which cause image artifacts in diagnostic modalities such as Computer Tomography (CT) and Magnetic Resonance Imaging (MRI). This issue can impede diagnosis and treatment of complications experienced by these patients, and may prevent accurate monitoring of the aneurysm. 
         [0007]    In particular, current MRI techniques exacerbate the interference properties of clips. For example, fast imaging techniques for MRI give rise to at least one order of magnitude in increased sensitivity to magnetic field inhomogenieties brought about by metallic clips. Field uniformities of one in 105 are preferred, but metal clips, particularly stainless steel clips, can reduce the homogeneity in the locality of the clip by orders of magnitude. Interferences are also seen using CT imaging techniques. Virtually all treated patients will require a post-operative MRI or CT scan to evaluate the aneurysm or a medical complication. Currently surgeons are severely limited in their ability to provide adequate care for this very dangerous problem. 
         [0008]    A large majority of patients with brain aneurysms are amenable to surgical clipping, with the exclusion of patients who have aneurysms very deep in the posterior blood circulation of the brain, or the base of the skull, both of which are difficult to reach with a surgical approach. In addition aneurysms where the ratio of the neck diameter to that of the largest dome of the aneurysm is greater than about 0.5 inches are more amenable to vascular coiling. 
         [0009]    There has been a continuous effort to minimize MRI artifact throughout the evolution of clip technology. Initially clips were made with steels that had some magnetic properties; these were dangerous because they could be forced to move by the magnetic field created by the MRI machine. Next, clips were made with non-magnetic steels that would not physically interact with MRI, but still obscure images. The latest designs use titanium which has less MRI imaging artifact than steels; but these clips still obscure images especially where the surgeon is trying to examine small features in the vasculature. For example, in the last decade there was an attempt to make a ceramic clip which would be MRI-invisible (see US Patent Application No. 2008/0004637 A1). However, a spring element made of titanium had to be incorporated in order to hold the ceramic jaws together because ceramic is not a viable material for springs as it does not carry tensile forces. 
         [0010]    It is therefore, desirable to produce a small, biocompatible, polymeric vascular clip. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0011]    The vascular surgical clip of the present invention is made of biocompatible material and accordingly minimizes interference with image diagnostic modalities such as CATSCAN and MRI. At the same time, the vascular clip is nearly the same size as comparable metal clips, while maintaining sufficient strength and possessing high reliability in the clip&#39;s latching mechanism in the closed position. The clip is configured to provide a secure means of handling and application to avoid premature release from an applier. 
         [0012]    In a first embodiment, the vascular clip of the present invention uses PEEK, or polyether ether ketone, a substance currently used extensively in orthopedic and spine surgeries. As noted above, monitoring clipped aneurysms, and diagnosing and treating post-operative complications, is often inhibited because of the extensive artifact caused on MRI and CT images. An artifact or interference caused by a metallic clip in a diagnostic or post-operative MRI or CT image is an obscuration that makes it difficult to see the anatomical features of the image and therefore diagnose proper cessation of bleeding of a vessel, and/or other post-operative complications. The minimal interference or zero artifact clip properties of the present invention could greatly improve the way SAH and aneurysm patients are treated and significantly reduce the overall cost both of treating an aneurysm, and these post-operative complications. 
         [0013]    The present invention of a vascular clip is essentially invisible under imaging (MRI) because it is made of biocompatible plastic. All vascular clips used for aneurysms on the market are made of metal because the designs employ a preloaded torsional spring that provides the necessary clamping force to cease blood flow and permanently affix the clip to the vessel. In order to generate this required clamping force using a spring-based design, a material with the stiffness and spring characteristics of a metal (e.g. titanium or steel) is required. The design of the present invention departs from the conventional torsional spring configuration and employs a snap-together configuration wherein the clip has a flexible frame member and rigid clamping member. The flexible frame, when squeezed by the surgeon&#39;s tool, provides for securing a tension member to a clasp to secure and clamp together the rigid clamping member with the required force. The tension member may further provide a clip applier access point to provide for the attachment of a surgical forceps or other tool to re-open and position the clip and then re-close and secure the vascular clip in the proper anatomical location to seal the vessel and stop blood flow. Alternative clasp mechanisms may use tensile fiber, such as dyneema with round or bulged ends to encircle the clip frame and clamp and secure the clip in a locked position. 
         [0014]    In a first embodiment the vascular or aneurysm clip may be made from a biocompatible material such as PEEK (Polyether ether ketone), that is known and commonly used in long-term medical implants because of its mechanical strength and biocompatibility. Applications of PEEK include implants in orthopedics, spine, cardiovascular, and neurology—including deep brain stimulation. An inherent advantage in the use of biocompatible plastics in this design is a reduction in costs as compared to clips made of titanium and other metals. Conventional metal design clips are made in a precision fashion requiring hand craftsmanship with tight tolerances at minute dimensions. In comparison, injection molding of biocompatible plastics is inherently cheaper and scalable so that costs of goods may be a fraction of the metal clips currently available. 
         [0015]    It is an object of the present invention to minimize or obviate interference and artifacts from MRI and CT imaging commonly seen in using metallic clips to stop blood flow. 
         [0016]    It is another object of the present invention that a vascular clip is formed having a flexible member securing a clamping member with adequate force to clamp a vessel and permanently cease blood flow. 
         [0017]    It is a further object of the present invention that the vascular clip be of a biocompatible material and comparably dimensioned to the metallic clips of the prior art. 
         [0018]    It is a further object of the present invention that the vascular clip is manufactured from a plastic biocompatible material such as PEEK. 
         [0019]    It is a further object of the present invention that the vascular clip provides a clamping force of between 50 to 500 grams of force and more specifically between 100 and 300 grams of force. 
         [0020]    It is a further object of the invention that the latching mechanisms of the present vascular clip facilitates re-opening and re-closing of the mechanism to properly place and seal a vessel and to secure the clip in the proper position to permanently cease blood flow. 
         [0021]    It is a still further object of the present invention that the vascular clip be manipulated by and releasable to re-position using a surgical clip applier. 
         [0022]    The present invention is related to a re-attachable vascular clip comprising two jaws having clamping surfaces, two flexible members manipulating the two jaws to close, a tension member latching the two flexible members to lock the two jaws in a closed position; and wherein unlatching the tension member unlocks the two jaws. In the re-attachable vascular clip the tension member may be pivotably attached to at least one of the two flexible members. The tension member may comprise a first and second tension arm or a single tension arm. The re-attachable vascular clip may further have the tension member comprising opposing clasps. In the re-attachable vascular clip, the tension member may further comprise a clip actuator manipulating the tension member to latch and unlatch the two flexible members. In the re-attachable vascular clip the two jaws may close at a clamping force in a range of 50 to 500 grams of force and the vascular clip is a biocompatible plastic material which produces no imaging interference. 
         [0023]    The present invention is further related to an aneurysm clip producing minimal interference in imaging comprising a compressible frame of a plastic material, a clamping member extending from the compressible frame; and wherein compressing the frame produces forces at the clamping member in a range of 50 to 500 grams of force. The aneurysm clip producing minimal interference in imaging may further comprise a latching member holding the frame in a compressed state and the latching member may release the frame from a compressed state. The latching member may further pivot from the frame. The latching member may further comprise first and second clasps. The aneurysm clip producing minimal interference in imaging may further comprise a frame of a substantially rectangular shape. The aneurysm clip producing minimal interference in imaging may further comprise a frame of a substantially elliptical shape. The clamping member may have one of at least a curved, rounded, and angled shape and may further comprise an angular extension. 
         [0024]    The present invention is further related to a method of applying a zero artifact vascular clip to a vessel to cease blood flow, comprising the steps of locating the open jaws of a vascular clip around a vessel, closing the jaws of the vascular clip around the vessel, compressing a frame affixed to the jaws to apply adequate force to the vessel to cease blood flow, locking a tension member using an actuator of a clip applier to hold the frame in compression. The method of applying a zero artifact vascular clip to a vessel to cease blood flow may further comprise the steps of unlocking the tension member, decompressing the frame affixed to the jaws, opening the jaws of the vascular clip, repositioning the vascular clip around the vessel and closing the jaws of the vascular clip, compressing the frame affixed to the jaws to apply adequate force to the vessel to cease blood flow, locking the tension member using the actuator of the clip applier to hold the frame in compression. 
         [0025]    These and other features, advantages and improvements according to this invention will be better understood by reference to the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    Several embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which: 
           [0027]      FIG. 1  is an embodiment of a vascular or aneurysm clip of the present invention in a closed and locked position clamping a vessel; 
           [0028]      FIG. 2  is an exploded view of a vascular clip according to an embodiment of the present invention; 
           [0029]      FIGS. 3A and 3B  are detailed views of embodiments of hinges of an embodiment of the vascular clip of the present invention; 
           [0030]      FIG. 4  is a perspective of an embodiment of the vascular clip of the present invention in an open state; 
           [0031]      FIG. 5  is a side view of an embodiment of the vascular clip of the present invention with the jaws open; 
           [0032]      FIG. 6  is a side view of an embodiment of the vascular clip of the present invention in the closed and latched position clamping a vessel and illustrating the forces acting on the frame and the vessel; 
           [0033]      FIG. 7  is a side view of an embodiment of a vascular clip of the present invention in a closed but not latched position as held by a surgical tool; 
           [0034]      FIG. 8  is a perspective view of an embodiment of the vascular clip of the present invention held by a surgical tool; 
           [0035]      FIG. 9A  is an embodiment of a vascular clip of the present invention in a closed but not latched position as held by a surgical tool; 
           [0036]      FIG. 9B  is an embodiment of a vascular clip of the present invention in a closed but not latched position as held by a surgical tool; 
           [0037]      FIG. 10  is a further embodiment of a vascular clip of the present invention with a single tension arm in a prepared open position; 
           [0038]      FIG. 11  is a side view of an embodiment of an upper deflection member of showing a pivot fastener extending from the interior surface of a deflection member of a vascular clip of the present invention; 
           [0039]      FIG. 12  is a perspective view of an embodiment of the tension member as opposing clasps in a still further embodiment of a vascular clip of the invention in the open configuration; 
           [0040]      FIG. 13  is a perspective view of an embodiment of the frame in an elliptical shape in a still further embodiment of a vascular clip of the present invention in the open state; 
           [0041]      FIGS. 14A-14C  illustrate the still further embodiment of a vascular clip of the present invention with the frame in an elliptical shape showing the clip in the open, partially closed, and closed and latched positions; 
           [0042]      FIG. 15  is a perspective view of an embodiment of the vascular clip of the present invention with the frame in an elliptical shape in an open position; 
           [0043]      FIG. 16  is a perspective view of an embodiment of the vascular clip of the present invention with the frame in an elliptical shape in a closed and unlocked position; 
           [0044]      FIG. 17  is a perspective view of an embodiment of the vascular clip of the present invention with the frame in an elliptical shape in closed and locked position; and 
           [0045]      FIGS. 18A-18G  are top views of embodiments of optional jaw geometries of a vascular clip of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    The vascular clip of the present invention may be used in a number of applications to cease blood flow from a vessel in the human body. The zero artifact features make the vascular clip particularly well suited for the treatment of aneurysms within the brain. Aneurysms, such as subarachnoid type, in the brain are treated typically by coiling or clipping. The number of cases is divided approximately 50/50 between the two methods. Clipped aneurysms are of interest for this innovation. Clipping using a vascular or aneurysm clip blocks blood flow so that the aneurysm will clot and cease expanding so as not to burst or leak. The clip clamps the proximal blood vessel that feeds the aneurysm. Metallic clips of the prior art are made by various manufacturers with variations in size, shape, and holding/clamping force, but typically the designs are the same with a torsional spring and clamp or jaw. Forces of the jaw or clamp are on the order of approximately 100 to 300 grams of force. This is the force that is applied to the vessel to cease blood flow. Since the force of, for example, 100 grams of force is at a closed state with the jaws aligned and compressed together, the torsional spring of the prior art is preloaded during manufacture, that is, when provided to the surgeon they are in the normally closed position. The clips of the prior art are commonly made of titanium or steel or other alloys in order to accommodate the required preloading of the torsional spring. The metallic properties of these clips of the prior art can create the image artifacts and interferences that obscure accurate imaging of the brain vasculature, which requires detailed resolution. The non-metal MRI clip of the present invention has substantially zero effect on MRI and CT imaging. 
         [0047]    An inherent design challenge using biocompatible polymers is developing enough clamping force w/o yielding the material such that it deforms out of place or loses stiffness. For this reason a plastic clip in a similar sized spring design as a metallic clip cannot produce sufficient clamping force because plastics are so low in modulus (stiffness) compared to metallic substances. The clamping force of a plastic clip of similar dimensions would be insufficient where acceptable forces may only be achieved by increasing the overall size which will be far too large to use as a vascular clip. For example carbon fiber reinforced peek (CFRP PEEK) has a Modulus of Elasticity o 18 GPa which is at the upper end of the range for polymers. In comparison, Titanium Ti G-4 commonly used in metallic clips has a modulus of 120 GPa which is about seven times that of CFRP PEEK. 
         [0048]    In evaluating how the material stiffness will affect spring performance, the basic linear equation for the stiffness of a torsional spring demonstrates that the required forces could not be achieved within the dimensional requirements of approximately 3 mm-8 mm in diameter for the torsional spring in a surgical vascular clip. 
         [0049]    Torsional Spring Stiffness
       k=d 4 E/10.8DN   d=wire diameter
           E=Young&#39;s Modulus   D=coil diameter   N=# of coils   
               
 
         [0055]    For a spring with the same geometry but made of CFRP PEEK there is therefore a loss of stiffness by a factor of at least 7. This analysis is based on the assumption that a spring could be molded in the same manner as a wound metal spring, which is difficult or impossible with current manufacturing technologies. Since a plastic torsional, or coil spring, analogous to the prior art is not feasible, flexural designs are considered. In the design of a first embodiment of the present invention and in contrast to the prior art, the clamping force as shown in  FIG. 1  is caused by a flexible frame  14  formed using deflection beams  20  and  22  that are pulled towards one another using a tension member  16  and secured using a clasp  18  within the frame structure  14  to induce compression between the clamping members  12 , thus holding the jaws  24  and  26  together. A vessel  8  is secured between the jaws  24  and  26  of the vascular clip  10  with sufficient force to seal the vessel and cease blood flow. The approximate force is in a range of 50 to 500 grams of force and more specifically between 100 and 300 grams of force. As shown in  FIG. 2 , the vascular clip  10  is formed with an upper clip member  11  that is affixed to a lower clip member  13  using a shaft  62  and barrel hinge  60  that provides for the clip members  11  and  13  to rotate within the hinge  60  and open and close the clamping member  12 . The terms upper and lower, vertical and horizontal demonstrate a relationship of the elements and are not used to restrict the orientation or use of the present invention. The tubular shaft  62  of the upper clip member  11  slides in and is secured within the barrel receptor  64  of the hinge  60  on the lower clip member  13 . A pivot abutment  66  provides for lateral adjustment of the shaft  62  within the receptor  64  in order to align the jaw members  24  and  26  and prevent misalignment or scissoring meaning that one jaw extends across the other jaw at an angle. By adjusting the jaw members  24  and  26  into alignment a greater surface area is available to contact and secure a vessel  8 . After alignment, a retaining channel  65  as shown in  FIG. 3A  may be crimped, heated staked or otherwise treated to secure the clip member  11  in position within the barrel receptor  64 . For example, by flowing material from the retaining channel  65  of the barrel receptor  64  over the shaft  62 , the shaft  62  is retained but still allowed to rotate to open and close the clamping member  12 . In a further embodiment as shown in  FIG. 3B  a cap  67  may be adhered to the barrel receptor  64  to retain the shaft  62  and align the jaw members  24  and  26  in parallel. It is within the scope of the present embodiment, and it will be understood by those skilled in the art, that there are various ways to retain a shaft within a receptor so as to form a rotatable hinge. For example in further embodiments, the shaft may be retained within the hinge using a shim or stopper to position and align the jaws  24  and  26  of the clamping member  12 . The rotatable hinge  60  is positioned along a support structure of the frame  14  with an upper vertical support member  21  supporting the shaft  62  on clip member  11  and a lower vertical support member  23  supporting the barrel receptor  64  on clip member  13 . 
         [0056]    In assembly of the vascular clip  10 , the tension member  16  may be installed by inserting the upper clamping member  11  through the tension arms  44  of the tension member  16  and affixing the tension member  16  to a pivot hinge  40  as described in further detail herein. In attaching the upper and lower members  11  and  13 , the flexible frame  14  and clamp  12  are formed. The flexible frame  14  includes upper and lower deflection beams  20  and  22  connected through the vertical member supports  21  and  23  that includes, in this first embodiment, the rotatable hinge  60  consisting of the shaft  62  and barrel receptor  64 . In further embodiments the upper and lower vertical supports  21  and  23  may be of a shortened length that would provide for a shortened length of the tension member  16  and an overall shortened vertical profile of the frame member  14  and in the range of 4 mm-8 mm in height. The upper and lower vertical supports  21  and  23  extend through curved supports  69  and  71  to attach each of the upper and lower deflection beams  20  and  22  as shown in  FIG. 4 . The curved structure is formed substantially perpendicular to the vertical support structure at an angle approaching 90° and in further embodiments it may be of any angle in a range of approximately 45° to 130°. The deflection beams  20  and  22  extend to upper and lower transition support members  70  and  72  forming the flexible frame  14 . The deflection beams  20  and  22  may as well be of a longer dimensional length than shown providing for a lengthened horizontal profile of the frame member  14  and in the range of 7 mm-15 mm in length. 
         [0057]    Extending from the rigid transition support members  70  and  72 , upper and lower stiffening members  74  and  76  extend to the upper and lower jaws  24  and  26 . The transition and support members  70  and  72 , the stiffening members  74  and  76 , and the jaws  24  and  26  form the clamp  12  of the vascular clip  10 . Different from the two deflection beams  20  and  22 , the transition support members  70  and  72  and the upper and lower stiffening members  74  and  76  may be of a thicker dimension to rigidly extend and support the upper and lower jaws  24  and  26  without substantially flexing or deforming when the deflection members  20  and  22  are in compression as described herein. 
         [0058]    As shown in  FIG. 2 , in the exploded view, the tip  28  of the upper jaw leg  24  is inserted through the legs  44  of the tension member  16  and the tension member  16  is slid along the jaw leg  24  and jaw support member  74  and transition member  70  to the pivot hinge  40 . The barrel cylinder  46  or other attachment mechanism of the tension member  16  is snapped or otherwise affixed to the pivot hinge  40 . The cylindrical shape of the barrel  46  and extending prongs  42  of the hinge  40  allow the tension member  16  to rotate and swing freely within the frame handle  14 . 
         [0059]    As shown in  FIG. 4 , the clip members  11  and  13  rotate around the hinge  60  to open and close the jaw members  24  and  26  of the vascular clip  10 . The contact surfaces  32  and  34  of each of the jaw members  24  and  26  extend from a proximal point  78  and  79  to a distal end point or tip  28  and  30  respectfully. The contact surfaces  32  and  34  may have a textured grid, or ribbed surface  25  to assist in frictionally adhering a vessel  8  to the surfaces  32  and  34  within the clamp  12 . In a first embodiment, the stationary clasp  18  is formed in a hook shape with a rounded exterior surface  52 , and an attachment latch  54  that extends a distance Cd from the upper surface  29  of the lower deflection member  22 . This distance Cd is substantially the same as the diameter of the barrel cylinder  46 . The attachment latch  54  of the clasp  18  extends approximately ⅓ of the distance Cd towards the lower deflection beam  22 . In an open and unlocked state the jaws  24  and  26  may be opened or closed with the tension member  16  free to swing about the pivot hinge  40  from the upper deflection member  20 . This rotational movement is designated with arrows in  FIG. 5 . In an open state the deflection beams  20  and  22  are unflexed and extend laterally from the curved frame members  69  and  71  and the vertical supports  21  and  23 . In this state even with the jaws  24  and  26  touching one another, the clamping force Fc is essentially zero because the tension member  16  is not latched to the clasp member  18  and therefore the upper and lower deflection members  20  and  22  are not deflected. In this form, the clip  10  is essentially in a static unsecured or unlocked state. 
         [0060]    In a closed state, it is an important feature of the invention that when the clip  10  is clamped onto a vessel  8  and is latched all of the clamping force Fc is applied through the vessel  8 . A person skilled in the art will realize that a flexural structure such as the clip  10  of the current embodiment may be simulated using computer simulation techniques such as finite element analysis (FEA) in order to predict the deflections and forces in the structure, and to tune the resulting parallelism of the jaws  24  and  26  when the clip  10  is clamped and latched. The jaws  24  and  26  are substantially parallel when the vessel  8  is clamped therein and a gap is shown at the tips  28  and  30  and proximal ends  78  and  79  of the jaws  24  and  26  where the contact surfaces  32  and  34  do not touch. In order to accomplish this, the angle θ is derived through an analysis of the rotation R of the transition support members  70  and  72  with respect to the flexion members  20  and  22  and an analysis of the structural elements and forces within the clamping and frame members  12  and  14 . Through the analysis of these forces and the amount of deflection, an adjustment to the angle θ is made to optimize the amount of rotation so that when a vessel  8  is between the contact surfaces  32  and  34 , the jaw members  24  and  26  meet and are in parallel to each other and the clamping force Fc is directed to the vessel  8  in the area between the proximal and distal ends of the jaws  24  and  26 . As illustrated in  FIG. 6 , in compressing the deflection members (F A ) rotational forces R drive the proximal ends  78  and  79  at each base of the transition members  70  and  72  to approximate causing the tips of the jaws  28  and  30  to separate designated as T until the contact surfaces  32  and  34  are in parallel with one another. Therefore, the contact surfaces  32  and  34  of the jaws  24  and  26  do not contact one another when the tension member  16  is locked and a vessel  8  is sealed and clamped within the jaws  24  and  26 . However, the contact surfaces  32  and  34  may be in contact at the tips  28  and  30  when the clamp  12  is closed, the tension member  16  is not latched or in a locked position and there is no vessel  8  within the clamp  12 . 
         [0061]    In order to seal and clamp a vessel  8  and thereby restrict blood flow the clamping force must be in a range of approximately 50-500 grams of force as described above. The overall dimensions of the frame handle of the vascular clip are approximately 7 mm-25 mm in length and 4 mm-15 mm in height, or the height is approximately one half of the overall length of the clip  10 . A jaw leg may be on the order of 1 mm-2 mm in diameter or thickness and the jaw support member  74  and transition member  72  may be 1 mm-3 mm thick to provide support and rigidity to the jaw leg members  24  and  26 . The deflection members  20  and  22  may be of a minimal thickness of roughly ½ mm to 2 mm and be flexible thereby when a force is applied perpendicularly to the member shown as F A  in  FIG. 6 , the deflection members  20  and  22  bend or deflect. As shown, the tension member is of a length of approximately 75%-85% of the unflexed length of the clip frame handle  14 , and therefore force F A  must be applied to the deflection members  20  and  22  to reduce the overall distance between the upper and lower deflection members and provide for the attachment of the tension member  16  to the clasp  18  of the lower deflection member. With an applied force of ˜0 the deflection members  20  and  22  are at rest along datum D 1 . By applying the adequate amount of force F A  to attach the tension member  16 , the deflecting beams  20  and  22  will deflect to a maximum datum of D 2 . The length of the tension member  16  determines the clamping force F c  realized at the jaws when the tension member  16  is attached and the clip  10  is in a locked position as described in further detail herein. 
         [0062]    In the present embodiment, there are two critical criteria for obtaining the desired clamping force Fc as follows; 
         [0063]    1. The applied (input) force F A  (which is held by the clasp) must be at least greater than the clamping force F C . Therefore the material and geometry must be stiff enough to provide this force F C  (at the jaws). 
         [0064]    2. The applied (input) force F A  must not cause the jaws to spread open. 
         [0065]    To be comparable to metallic clips of the prior art and to provide the necessary force to seal and prevent further blood flow through a vessel, the clamping force Fc must be in a range of 50 to 500 grams of force and more specifically in a range of 100 to 300 grams of force. As a starting point, an assumption is made that F A , the applied force for the deflection of the deflecting beams, is located directly between F H , the applied force at the hinge and F C  the clamping force, therefore F H =F C  and F A =2F C . This is the starting point for the analysis of the flexion. A requirement of the present invention is that the deflection of the deflection beams must be such that the required force (2Fc) causes enough deflection in the beams  20  and  22  to enable the clasp  18  to catch the tension member  16 . In order to maintain the clamping force Fc within this acceptable range, an important feature of the present invention is applying force to the deflection beams  20  and  22  to compress the deflection beams  20  and  22  and to lock the tension member  16  and seal a vessel  8  using the clip applier  80  of the present invention. 
         [0066]    In a first embodiment, the clasp member  18  is positioned directly opposite the pivot hinge  40  or at a slight offset along axis Y that extends through the upper deflection member pivot hinge  40 . The tension member  16  aligns substantially linearly along the Y axis from the pivot hinge  40  and when the deflection members  20  and  22  are compressed the tension member  16  attaches to the clasp member  18  of the lower deflection member  22 . The clasp member  18  may have a hook  54 , snap fastener or other locking mechanism that facilitates the attachment of the barrel cylinder  46  or other attachment mechanism of the tension member  16  to releasably secure the tension member  16  to the lower deflection member  22  and hold the deflection members  20  and  22  in compression. 
         [0067]    As shown in  FIG. 7 , clip applier forceps  80  securely hold the vascular clip  10  to open, maneuver and manipulate the clip  10  to surround and clamp a vessel  8 . A set of engagement pins  81  mounted to each end effector  82  and  84  engage the inside of each of the deflection members and provide for separating the clip members  11  and  13  to open and close the clip  10 . A pair of forceps arms  83  and  85  provides for releasing of the clip  10  when the clip is properly positioned to clamp a vessel  8 . Compression force to flex the deflection members  20  and  22  and apply force to the clamp  12  is performed using end effectors  82  and  84  that include a contoured surface that is complimentary to the outer surface of deflection member. As shown, the upper end effector  82  may include a cup shaped member  86  that interfaces with the pivot hinge  40  to assist in holding and maneuvering the clip  10 . The lower end effector  84  may include a rounded bulged surface  88  to apply force to the center of the deflection member  22  that, along with the compression of the upper end effector  84 , reduces the distance between the deflection members  20  and  22  to a distance that is less than the length of the tension member  16 , so that the tension member  16  will reach and latch to the clasp  18 . Other end effector features may serve as locaters and connectors to securely hold the clip  10  until it is finally positioned and clamped to seal a vessel  8 . 
         [0068]    Importantly, the tension member  16  in rotating about the pivot axis P provides for a latch actuator  90  of the clip applier  80  of the present invention to manipulate the tension member  16  to a latched and unlatched position by pushing the member  16  into place to lock the clip  10 , or alternatively pulling the member  16  out of the clasp  18  to unlock the clip  10 . The actuator arm  91  extends to a control handle  96 . The latch actuator  90  is shown in isolation in  FIG. 8  showing the actuator arms  92  and  93  extending out from a base plate  94  of the latch actuator  90  to align on either side of the tension member  16  to push or pull the tension member  16 . By moving the actuator trigger  96 , shown in  FIG. 9A , the tension member  16  may be moved from a locked to an unlocked position using the actuator arms  92  and  93  by swinging the tension arm  16  around the pivot axis P while the end effectors  82  and  84  may maintain pressure on the clip  10  and thereby hold a vessel  8  within the clamp  12  while locking and unlocking the clip  10 . This feature is critical to allow a surgeon to place the clip  10  and determine if there is a cessation of bleeding. If there is still blood flow or if the clip is otherwise positioned in an undesirable location in the anatomy, the surgeon may unlock the clip  10  using the actuator trigger  96  and reposition the clip  10  on the vessel  8  at the desired anatomical location. The upper and lower compression handles  97  and  98  may be manipulated to hold, maneuver, compress, and release the clip  10 . As shown in  FIG. 9B , the clip  10  may be in a non-flexed position and be held and manipulated by the clip applier  80 . 
         [0069]    As shown in  FIGS. 9A and 9B , the very small size of the vascular clip  10  requires that the clip applier  80  must hold, compress and adjust the clip  10  from an open to a closed position. The clip applier  80  of the present invention is further of an ergonomic design that provides for minimal force and acuity to be needed to efficiently maneuver and attach a clip  10 . The compression using the clip applier flexes the deflection members  20  and  22  and these members  20  and  22  remain flexed when the tension member  16  is secured by the clasp  18  to the vessel  8 . The amount of deflection is primarily determined by the material thickness and modulus of elasticity of the plastic of the deflection members  20  and  22  and the length of the tension member  16 . 
         [0070]    In further embodiments such as shown in  FIG. 10 , the vascular clip  110  is formed with a single sided tension member  116  as shown. In this embodiment, the tension member  116  is secured within an enclosed full-round pivot fastener  140 . The retaining cylinder  146  may be secured with an oversized mushroom flange  147  or boss, or using a heat stake or heat treatment to deform the plastic and retain the tension arm  116  within the enclosed pivot fastener  140 . The tension arm  144  may be thickened to provide additional support when securing the arm  144  to the clasp  118  and to support the grip of the applier  80  in manipulating the tension member  116  to open and close the clamp  112 . The jaw members  124  and  126  may be formed similarly to previous embodiments with thickened transition support members  170  and  172  and stiffening members  174  and  176 , the jaw members  124  and  126  extending from proximal points  178  and  179  where the frame member  114  meets the clamp member  112  to the jaw tips  128  and  130 . The contact surfaces  132  and  134  of the jaws  24  and  26  may also be similarly formed with a grid or grooved surface  125 . The pivot fastener  140  provides for the tension arm  116  to rotate around pivot axis P and be fastened to the clasp member  118 . The clasp  118  is similarly formed with a rounded arched surface  152  and a nubbed or protruding end attachment latch  154 . The tension arm  144  is also similarly formed with a barrel cylinder  146  that may be secured within nub or protrusion of the attachment latch  154 . The angle θ is determined through a similar analysis to the prior embodiments to minimize the amount of rotation so that when a vessel  8  is between the contact surfaces  132  and  134 , the jaw members  124  and  126  meet and are in parallel to each other and the clamping force Fc is directed to the vessel  8  in the area between the proximal and distal ends of the jaws  124  and  126  as previously described. 
         [0071]    In further embodiments, the pivot fastener  140  may extend from the interior surface  129  of a deflection member  120  as shown in  FIG. 11 . A shorter tension member may then be used to provide adequate clamping force Fc in securing the tension arm to the clasp. Other fasteners or retainers that provide for the tension arm to pivot or swing are contemplated within the scope of the present invention. 
         [0072]    In further embodiments of the vascular clip  150  such as shown in  FIG. 12 , the locking mechanism may be formed from a pair of opposing clasps or hooks  117  and  119  that extend from the interior surfaces  127  and  129  of each of the deflection members  120  and  122 . The hook fasteners  117  and  119  may be the same size and dimension or either fastener may be longer than the other fastener with each fastener affixed to each deflection member  120  and  122  using a flexible hinge  141  that provides for rotational movement of the hook fasteners  117  and  119  around the pivot axis P. To lock and secure the vascular clip  150 , the upper and lower hook fasteners  117  and  119  overlap so that by using a clip applier  80  to compress each of the deflection members  120  and  122  the outer surfaces  153  of each of the fasteners  117  and  119  flex about the flexible hinges  141 , make contact with one another and brush along each of the surfaces  153  until the latching nubs or protrusions  155  engage and interlock and the fasteners  117  and  119  flex back approximately into their initial positions along the Y axis locking the jaw members  124  and  126  with sufficient force Fc. The hook clasps or fasteners  117  and  119  may further provide a clip applier access point  143  to provide for the attachment of surgical forceps  80  or another applier tool to open, position and close the vascular clip  150  and reopen as necessary and reposition in the proper anatomical location to seal a vessel  8  and stop blood flow. The angle θ is also determined through a similar analysis to the prior embodiments to minimize the amount of rotation so that when a vessel  8  is clamped between the contact surfaces  132  and  134 , the jaw members  124  and  126  meet and are parallel to each other and the clamping force Fc is directed to the vessel  8  in the area between the proximal and distal ends of the jaws  124  and  126  as previously described. Alternative applier mechanisms may use tensile fiber, such as dyneema with round or bulged ends to encircle the clip frame and clamp and secure the vascular clip in a locked position. Access points may be positioned on the tension member or clasp to provide for a clip applier to grasp the tension member and swing or otherwise adjust the member around a pivot axis to position the clip in a closed and secure location, and re-open and re-position and re-close and secure the clip to properly seal the vessel and stop blood flow. 
         [0073]    In this embodiment the vascular clip  150  is formed as a single unitary piece with a living hinge  161  that provides for the clip  150  to open and close. The living hinge  161  may be formed along the vertical support  168  of the frame  114  with the hinge region  161  formed by diminishing the amount of material within this region to provide for bending of the vertical support  168  in opening and closing the jaw members  124  and  126 . The upper and lower members  121  and  123  of the vertical support  168  may also be of an increased thickness to rigidly support the deflection beams  120  and  122  in compression. The vertical members  121  and  123  extend to curved members  169  and  171  that are formed substantially perpendicular to the vertical support structure  168  at an angle approaching 90° and in further embodiments may be of any angle in a range of approximately 45° to 130°. 
         [0074]    In further embodiments, the vascular clip  210  is formed with a frame member  214  in a crescent, elliptical or semicircular shape as shown in  FIG. 13 . In this embodiment the vascular clip  210  may have a lower vertical profile and a smooth overall shape that is atraumatic when inside the body. The jaw members  224  and  226  are similar to prior embodiments, and extend from proximal transition points  278  and  279  between the frame  214  and the clamp  212  to the jaw tips  228  and  230  with similar contact surfaces  232  and  234  that may be gridded or ribbed  225 . However, instead of transition support and stiffening members, a support rib  270  may extend from the transition points  278  and  279  between the clamp  212  and frame  214  to stiffen and hold the jaw members  224  and  226  substantially rigid during compression of the frame members  220  and  222 . 
         [0075]    The vascular clip  210  may be formed as a single unitary piece with a living hinge  260  connecting the upper and lower deflection members  220  and  222  and providing for the clip  210  to be opened and closed. The living hinge  260  may allow the clip  210  to open at an angle α that may be in a range of approximately 30° to 160° and more specifically to a range of 45° to 80° to provide for the applier tool  80  to grip and maneuver the clip members around a vessel  208  for clamping. The tension member  216  may be affixed to the interior surface  227  of the upper deflection member  220  and extend using a flexible hinge  240  to swing around pivot axis P. It will be appreciated by one skilled in the art that this embodiment may alternatively be constructed with a hinged pivot with a tension member and latch as shown in previous embodiments. A clip applier  80  may grip the upper and lower deflection members  220  and  222  to hold and maneuver the clip  210  to the proper position and then compress the clip  210  and shorten the distance D between the deflection members  220  and  222  to have the tension member  216  reach and connect to the clasp  218  as shown in  FIGS. 14A-14C . As the clip  210  is compressed the distance D is shortened from a distance D 1  to an intermediate distance D 2  and finally to a latched distance D 3 . The derived angle θ for this embodiment may provide for the tips of the clamp  212  to toe-in and meet when the clamp  212  is closed before the vessel  208  is clamped within the clip  210  and for aligning the jaw members  224  and  226  in parallel such that the contact surfaces  232  and  234  not touching when a vessel  208  is within the clamp  212 . In  FIG. 15 , the clip  210  is shown in an open position with access points  287  on one or both of the upper and lower deflection members  220  and  222  to attach a clip applier to hold the clip  210  and control the opening and closing of the clip  210 . As shown is  FIG. 16 , in a partially closed position, the derived angle θ provides for the tips  228  and  230  to mate first when no vessel  208  is within clamp  212 , and have the jaw members  224  and  226  align in parallel when a vessel  208  is clamped within the jaw members  224  and  226  as shown in  FIG. 17 . 
         [0076]    In any of the embodiments described herein the vascular clip may be formed with jaws that are curved, rounded, angled or have perpendicular or other angular extensions from the clamp surface  12  as shown in  FIGS. 18A-18G . The optional jaw geometries provide for a selection of the proper tip style to accommodate surgical and anatomical requirements. For example, the aneurysm may be within a portion of the brain that is particularly difficult to access, and the proper jaw clamping surface provides for the insertion around critical anatomical areas and assists in supporting the vessel to properly lock and secure the clip to stop blood flow. The properly secured clip of the PEEK or other biocompatible material provides for zero artifacts and interference in MRI, CT and other diagnostic equipment. This significant benefit allows for improved analysis and reduces post-operative complications. 
         [0077]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.