MXPA98010262A - Clamp stretch - Google Patents

Abstract

The present invention relates to a clamp for rigid but releasable clamping for an article having a fastening portion of predetermined shape and size, the clamp comprises an elastic body having an opening extending within the body, the aperture is sized slightly smaller than the fastening portion, the clamp includes connection means to which an external drawing force can be applied in one direction and magnitude, to cause the aperture to expand elastically enough to receive the fastening portion, thereby as the stretching force is released, the opening contracts elastically towards its initial size to be held on the portion for sujet

Description

STRETCHABLE CLAMP Field of the Invention The invention relates to the field of fastening and fastening devices, and particularly to said devices that are useful in the field of medicine for fastening bones and prostheses. Background of the Invention In modern surgical techniques involving the placement of prostheses or holding bones and fragments of bones together, a variety of fasteners are available to the surgeon. Probably the most widely used fastener is a bone screw that is screwed into predrilled holes in various bones and prostheses. See, for example, US Patents. Nos. 5,466,238 and 5,474,553. The bone screws are the primary mechanical fasteners. They are commonly expensive and should be stacked in a variety of sizes, to be ready to use when your patient is in the operating room. Bone screws are invasive, and although they can serve to reinforce a bone by attaching a liner or rebar to the bone, the bone itself is weaker as a result of creating a stress concentration around the threaded hole and at a long base due to the protection of bone tension by the implant. Substantial effort must be made by a surgeon to properly locate when a bone screw is to be placed and once a bone screw has been threaded into a bone, the position of the screw can not be changed. Conversely, if a different location is required, a separate hole in the bone must be drilled. More particularly, in the method for stabilizing a fractured bone or a fusion site, it is common to use bone screws to attach a plate or rod to the bone structure and provide interlocking between the bone screw and the plate or rod. The interlocking between the screws and the plate or rod is typically mechanical and involves threaded fasteners, washers and / or crimped joints. Sufficient torque or other force must be applied to ensure adequate interlocking and longevity of the interlock. Deficient interlocking systems can cause the joint to loosen and fail, resulting in fracture failure, fixation or fusion. Therefore, the success of the interlocking device of this nature is highly dependent on the knowledge and skill of the surgeon. Other fasteners have involved the use of cement such as the type used to anchor implanted hip rods in the proximal femoral intramedullary canal of a patient in the implant of an artificial hip.

However, other fasteners involving metal cables that for example are passed around a fractured or chipped bone, to hold the bone pieces in place, the ends of the band are held together when folding or by the use of threaded fasteners . What is clearly required is an interlocking system that provides a predictable, reliable and consistent interlocking for fastening metal, plastic, composite and / or ceramic structures to the bone or to each other. An interlocking system is also required to stabilize a total joint replacement to the bone and attach increases to such an implant to compensate for bone loss or bone defects found in the surgery. SUMMARY OF THE INVENTION The present invention provides a clamp which, broadly speaking, is capable of rigidly but releasably holding an article having a clamped portion of a predetermined shape and size. In the field of medicine, the clamp can be used in connection with a band that surrounds a bone to hold the bone fragments together, or it can be used to clamp together a prosthesis, etc. The clamp comprises an elastic body that is preferably formed at least in part of super elastic alloy. The body has an opening that extends within its interior and preferably through it, the opening is dimensioned slightly smaller than the clamped portion. The clamp includes connection means to which an external stretching force can be applied in one direction and magnitude to cause the opening to expand elastically enough to receive the clamped portion. The mechanism for stretching the clamp may be inherent to the implant design and external force may be applied to move the clamp relative to an interlocking mechanism. As the stretching force is released, the opening is resiliently clamped over the holding portion. Preferably, the body has a dimension in a first orthogonal direction, which is substantially smaller than the dimensions in any of the other two orthogonal directions, the connection means being positioned to allow the opening to expand in a direction perpendicular to the first orthogonal direction. In one embodiment, the opening extends within the body in a direction perpendicular to the first orthogonal direction and in another embodiment, the opening extends within the body in a direction parallel to the first orthogonal direction.

In a preferred embodiment of the invention, there is provided an equipment comprising an article with a portion for fastening with first and second sections of predetermined size and shape, and a clamp for rigidly releasing the article. The clamp comprises an elastic body having an opening extending within the body, the opening being dimensioned slightly smaller than the first section to hold, but slightly larger than the second section of the portion for fastening. The clamp includes connection means to which an external force can be applied in one direction and magnitude to cause the clamp to move from the first section to the second section with concurrent elastic expansion of the "clamp" opening, whereby the clamp elastically restrained on the fastening portion In a highly preferred embodiment, the invention provides band fastening equipment comprising a clamp having a body formed at least in part from a super elastic alloy and having an opening extending to The equipment includes an elongated band, and a clamp lock having a surface that engages the band.The clamp lock includes a first portion having a cross-sectional configuration slightly larger than the opening in the clamp , a second portion having a slightly smaller cross-sectional configuration to the opening in the clamp and an intermediate portion having a tapered sliding surface between the first and second portions. The sliding surface is configured to allow the clamp to be forced onto the tapered sliding surface of the second section towards the first section with concurrent elastic expansion of the clamp, thereby releasing the force that displaces the clamp onto the surface of sliding, the clamp elastically rests on the band. The invention has particular utility in the medical field where it can be used to hold the ends of a band surrounding each other to stabilize bone fragments, and to aid in the assembly of various bone prostheses such as threaded pedicle devices, devices for fixation of trauma, external fixation devices, and to hold increases to implants to replace missing bone. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of an interlocking device of the invention shown that interlocks the ends of the band; Figure 2 is a perspective view of a band also shown in Figure 1; Figure 3 is a clamp body of the type employed in the clamp of Figure 1; Figure 4 is a top view of the clamp of Figure 3, with the clamp body illustrated in cross section; Figure 5 is a cross-sectional view taken on line 5-5 of Figure 3; Figure 6 is a perspective view of a manual force generating device, for use with clamps of the invention; Figures 6A and 6B are perspective views of elements of the device shown in Figure 6; Figure 7 is a perspective view of a clamp of the invention shown in association with pedicle screw arms attached to a support rod; Figure 8 is an exploded elevation view of the device of Figure 7 shown in partial cross section; - Figure 9 is a perspective view of a modified clamp body; Figure 10 is a plan view of a band with a clamp connected as illustrated in Figure 9; Figure 11 is an exploded perspective view of a portion of a useful instrument with the clamp of Figure 9; Figure 12 is an exploded perspective view of a fastening device of the invention; Figure 13 is a plan view of the device of Figure 12 in a portion unlocked in a band; and Figure 14 is a plan view of the device of Figure 12 in its locked position. DETAILED DESCRIPTION As will be apparent from the description that follows, the clamp of the invention employs an elastic clamp body which is preferably at least partially completely formed, of an elastic upper alloy such as nitinol, the body having an opening. The elastic feature of the body material allows it to be stretched to enlarge one or more dimensions of the opening in the plane normal to the axis of the opening, to allow the opening to receive a band or cable or other portion to hold an article (including several items that will be fastened together) that would not otherwise fit through the opening. When releasing the force tending to enlarge the opening, the walls of the opening fasten on the portion to be held in place. As used herein, "elastic", with reference to the clamp body, refers to the body's ability to deform from an original configuration upon application of an external force and to return to its original configuration, when the force is released. Figures 1-5 describe a clamp of the invention, which is used to hold the ends of a band together. The clamp and band combination is illustrated as 10 in Figure 1, which includes a clamp body 12 of a generally parallelepiped shape, the body having a thickness dimension ("t" in Figure 3) which is the smallest Of the three orthogonal dimensions, the other two dimensions, the height and width-are approximately the same. Extending through the width of the body of Figure 2 is a generally rectangular opening 14. Means of connection in the form of holes 16 are formed adjacent to the four corners of the clamp body, the holes extending at least partially through the thickness of the clamp body. In these holes 16 the pins of a force application device will be inserted as illustrated in Figure 6, as will be described below. A metal strip 18 is illustrated, the strip having an elongate body 20 (Figure 2) of generally rectangular cross section. The band 18 is preferably of uniform dimensions substantially throughout its length, but may have an enlarged description 22 at one end. The dimensions of the band are such that it can not pass freely through the opening 14 because the height ("h" in Figure 2) is slightly less than the corresponding height of the opening 14 in the clamp body. The band can be of any suitable metal such as titanium. Nitinol or another super elastic alloy may be used as the web material. With reference to Figure 6, a force generating device 30 can be employed to exert a strong stretching force on the body of the clamp to expose the opening in the clamp body. The device 30 comprises two elongated sections, 30, 32, 34. The sections 32 have an elongated forward open slot 35, over a portion of their length, the slot ends rearward in a perforation that relieves tension 36. Near the end At the front, the groove 35 widens into an elongated opening 33 having a race track or general oval configuration. The section 32 terminates forward in a nose portion having forward projecting pins 37, 40 oriented and spaced apart to be received within the connecting holes of the clamp body shown in Figures 2 and 3. The pins 37 project from the vessel 38 will be received in the two upper holes of the clamp body, and the projecting pins 40 will be received in the lower holes of the clamp body. The holes 16 are preferably rectangular in shape, like the pins 37, 40, in order to maximize the surface contact between the pin holes and also to maximize the shear plane area of the body between the holes and the neighboring edges of the body. The section 34 has a leverage projection 41 extending laterally near that front end and sized to receive in the oval opening 33 of the section 32. The projection 41 is also oval in shape and is dimensioned such that its outer surfaces they couple and leverage by spacing the facing walls of the opening 33, when the backward portions of the sections 32 and 34, which serve as handles, are compressed as illustrated by the arrows in Figure 6. By compressing the handles with each other, causes the pins 37, 40 to stop by stretching the clamp body of Figure 3 vertically as shown in that Figure, and thereby exposing the height of the opening 14 slightly enough to receive the band 18. While the opening 14 in this way it is maintained in its expanded position, the band can be inserted through the opening until the enlarged position 22 goes into butt confinement with the supe clamp body surface adjacent to the opening inlet, and the band therefrom can be passed around a bone, a prosthesis or other articles that will be supported or supported and then can be reinserted through the opening 14, as illustrated in FIGS. Figures 1 and 4. When releasing the stretching force, the height of the opening 14 elastically contracts at a height towards its initial size to hold strongly and securely against the portions of band received in the opening. It will be understood that the device of Figure 1, once in place can be easily adjusted by re-inserting the pins 42 of the stretching device, by stretching to open the opening 14 slightly to allow the band to loosen, and once the fastening device has been repositioned correctly, the force is removed to again secure the band firmly in the clamp body 12. Also, if the band is made of super elastic alloy such as nitinol, the band itself can stretch elastically with respect to one bone or the other. object to be clamped, with the ends of the band firmly clamped in the clamp body, the band thus exerts continuous clamping pressure on the body. As will be explained in more detail below, super elastic alloys can be elastically deformed beyond the so-called region of the Hoo e law.When the clamping body of a super elastic alloy such as nitinol is formed, it can be elastically deformed. body in a substantial proportion, allowing greater dimensional tolerances of the body opening and the article to be fastened in the opening Figure 7 describes a pedicle screw in 50. Pedicle bone screws can be placed in multiple vertebral bodies and interconnected with rods to stabilize the spine and promote bone fusion The interconnecting rods (illustrated at 58) are placed in a yoke structure conveniently designed at the head of each pedicle screw In Figure 7, the screw 50 has a threaded section 52 and a yoke formed of a pair of spaced arms 54, 56 between which the rod 58 is received. will comprise of Figures 7 and 8, the rod 58 is clamped between the arms 54, 56, when the arms themselves are forced together, one towards the other, and this is the function of the clamp 60 that will now be described. The clamp 60 is similar to the clamp of Figure 3, except that the openings 62, receive the clamping portion of an article is formed through a smaller thickness dimension of the clamp body rather than across its width slightly larger than as in the case with the opening 14 of Figure 3. Fastener holes 64 are formed near the corners of the clamp body 60, and a force generating device such as that shown in Figure 6 can be used to stretch the clamp body 60, in order to expand the opening in the direction of the arrow B in Figure 7. The opening 62 is dimensioned in a manner such that it can expand in the direction of the arrow B in order to receive the upper ends of both arms 54, 56. The upper ends of these arms may have slightly offset shoulders 66, as best illustrated in Figure 8, to assist the clamp body 60 in locking the arms 34, 56 and the rod 58 together. In any case, once the stretching force is released, the opening 60 elastically contracts to its initial position and strongly grasps the ends of the arms 54, 58 causing these arms to also hold them with the rod 58. it can also be noticed in Figure 8, the clamp body 60, once in place has a smaller surface 68 that can be placed to come into downward contact with the rod 58 by additionally holding the rod in place. The invention has particular application for connecting increases to the body of a bone prosthesis implant. For example, in the case of a total knee replacement, increases below the tibial plate or inside the femoral box, they are sometimes required to fill and replace bone defects or missing bone in the bone structure of the support. In one embodiment, an increase with a groove in its surface facing the implant is needed to slide on a cylindrical stake extending from the surface of the implant where the increase is required. A clamping band, preferably made of nitinol or another super elastic alloy, is stretched and held over the augmentation and prosthesis and held in place by a clamp body such as the one illustrated in Figure 3. When it is released from the force of stretch used to stretch the band, the band tends to shorten and stretches a clamping force in the increase, holding it to the implant. In a similar manner, increases can be easily connected by means of the invention to hip rods or acetabular cups in total hip replacement procedures.

With a further example of utility, trauma fixation devices can be assembled through the use of the invention. In an exemplary embodiment, a bone plate of known construction is formed of two or more sections that are hinged together by a sliding mechanism. The parts of the sliding mechanism can be held against sliding movement by stretching a clamp of the invention in such a way that the parts of the sliding mechanism are received in the opening of the clamp body. By releasing the stretching force, the clamp surely locks the parts of the mechanism sliding together. As yet another example of use, the invention can be employed in connection with external fixation devices, often employed with saturated bones. External fixation involves placing percutaneous pins in segments of a fractured bone and connecting the pins to an external structure to stabilize the fractured bone. The external structure employs a clamping mechanism that interlocks or secures the percutaneous pins to the connecting rod. The connecting rods are typically telescoping and use clamps to lock the telescoping sections together. A clamp of the invention can be configured of the invention can be configured to securely hold the pins and rods together and to hold each other against relative movement of the telescoping rod sections. With reference to Figures 9 to 11, there is illustrated a band fastening system, comprising the clamp 80 formed of a generally flat plate. The plate is generally parallelepiped in shape, and has a large, generally rectangular, central opening 82 extending through its thickness, the corners 84 of the opening being slightly rounded as illustrated in the drawing. As illustrated in this manner, the bracket 80 is in the form of a rectangular frame having side walls 88 and shorter end walls 90. An aperture for receiving the band 86 is formed through both side walls 88, as shown in FIG. illustrate The clamp of Figure 9 is employed in connection with a band 92 (Figure 10) having a width slightly greater than the width of the clamp openings 86. In a manner similar to that described above with example of Figures 1 to 6 , the application of the stretching force to the bracket 90 in the direction of the arrow shown in Figure 10, causes the openings 86 to elongate, so that the band can be received within the openings. In Figure 10, the band 92 is illustrated as having a free end 94, the band passing through the opening 86, around an object to be held such as a bone, and then running against the opening 86 in the same direction. Figure 11 shows a portion of a stretching tool similar to that shown in Figure 6, Figures 6, 6A and 6B, and reference is made to those Figures and the accompanying description of how the jaws of the devices are separated by leverage when the handles 34, 32 are manually compressed together. The device of Figure 11 is identical to that shown in Figure 6, except that the pins 37 extend from the nose portions of Figure 6 move with slightly rounded projections adjacent to Figure 11. Each projection has an outer surface 98 which is shaped and shaped so as to fit or fit in surface-to-surface contact against the outer surfaces 100 of the end walls of the clamp shown in Figures 9 and 10. That is, the projections 96 in the Figure 11, have outwardly directed flat surfaces 97 that contact flat surfaces 100 in the clamp of Figure 9, and slightly rounded corners 98 that contact the slightly rounded corners 84 of the clamp. Preferably, the outer surfaces of the projections 96 and the inner surfaces of the end walls of the clamps, they are carefully formed in such a way that they meet in wide surface-to-surface contact and without generating substantial stress concentrations when the clamp is stretched. Conveniently, when the clamp is stretched, the side walls 88 are subjected to substantially equal tension. Another embodiment of the invention is illustrated in Figures 12-14. In Figure 12, it is illustrated in clamp 110 generally in the form of a parallelepiped and having an elongated central aperture 112. The ends of the aperture are slightly rounded as illustrated in 114. In a similar manner to the clamp of the Figure 9, the clamp of Figure 12 comprises a generally rectangular frame having long side walls 116 and shorter end walls 118. The width of the openings 12 between the side walls is such as to easily admit the width of a passing band. once or twice through the opening. A clamp lock is generally illustrated at 120 in Figure 12. It comprises a pair of generally parallel bars 122 having rounded outer surfaces 124, configured to slidably engage the rounded ends 114 and the opening 112 in the clamp. Bar 122 are joined at one end by struts or columns 126. The bars and columns are preferably made of metal and can be welded together. Now with reference to Figure 13, a metal band at 130 is illustrated, the band passes through the opening in the clamp 110. In the clamp lock 120 it is illustrated in position with the band 130 passing between the columns 126. and also between the bars 122, the free ends of the bars 122 are oriented to enter the opening of the clamp. Figure 13 illustrates how the curved surfaces 38 and 124 of the rods are slightly tapered, such that they diverge in the direction of the columns 126. The confronting surfaces 125 (Figure 12) of the rods 122 can be placed flush or against the edges of the band 130 as illustrated in Figure 13, or may themselves diverge in the direction of the columns 126. In any case, it will be understood that by inserting the free ends of the rods 122 into the clamp opening 112 and movement cut from the clamp to the left in Figure 13, the clamp opening 112 will expand, while the walls 114 of the clamp will be leveraged outwardly by the outer surfaces 124 of the clamp lock. The movement of the clamp 110 in this manner can be effected through the use of pliers, the jaws of which can be positioned to contact the outer surface 127 of the bars 122 and the outer surface 117 of the clamp at each end of the opening 112, as illustrated in Figure 13. The clamp can preferably be forced in this manner to the left in Figure 13, until it comes to rest against the confronting walls of the columns 126, as illustrated in Figure 14. In FIG. In this position, the clamp exerts a compressive force on the rods 122, locking the rods against the band 130. It will be understood that the stretching force that is applied to the clamp bodies of the invention, can be directed in such a way to enlarge the opening in more than one direction to allow different structures to be fastened. For example, stretching forces can be applied to the clamp body in two directions at right angles to each other and perpendicular to the axis of the opening to more or less uniformly enlarge the aperture, so that a tube or tube can be received in the aperture. cylindrical rods. Once the drawing forces are removed, the walls defining the opening compress the rod or tube with some circumferential uniformity, to provide a firm grip. Although the clamp body can be made of any suitable elastic material such as polymers, compounds, stainless steel and other metals or metal alloys, superelastic alloys are greatly preferred. Superelastic alloys are those alloys that can deform to a greater degree than other metals and metal alloys, without taking a permanent adjustment. Various alloys have super elastic characteristics. Of these, an almost stoichiometric mixture of nickel and titanium, commonly known as "nitinol", is the most widely used and successful. In addition to having convenient mechanical characteristics, nitinol also has excellent biocompatibility. Superelasticity refers to a phase transition that occurs in a super elastic alloy when a deforming tension is applied externally. Nitinol, as well as other superelastic alloys, (sometimes called shape memory alloys) exist basically in any of two crystallographic forms. The shape of the alloy will depend on various variables including ambient temperature, chemical composition and thermomechanical history. Austenite is the main phase, characterized by a body with a centered cubic structure. Martensite, is a transition phase and is characterized by a monoclinic crystalline structure. In general, austenite will be present at higher temperatures than martensite.

Of importance to the present invention, austenite will be transformed into martensite when the alloy is deformed by an external force. The area of the alloy that is thus formed will remain in the martensite phase as long as the deformation force is maintained. When tension is relieved, the deformation portion will tend to resume its original shape and in doing so will return to the austenite phase. This phenomenon is the basis of superelasticity. The present invention uses super elastic alloys that at the temperature of use (commonly body temperature or room temperature) are in the austenite phase and form stress-induced martensite, when deformed by external force.

An additional benefit of superelasticity involves the ability of superelastic alloys to undergo enormous elastic deformation with substantially constant tension. Alloys that are not superelastic commonly exhibit approximate proportionality between increased stress and the resultant stress (Hooke's law) only until plastic deformation begins. If the stress is released after considerable plastic deformation, little shape recovery occurs. Superelastic alloys demonstrate proportionality between stress and strain within the region of Hooke's law until a yield stress is reached, but subsequently higher elastically recoverable stress occurs at substantially constant stress (as tension-induced martensite forms). By releasing the tension, the alloy returns elastically in an essential way to its original shape. While a preferred embodiment of the present invention has been described, it will be understood that various changes, adaptations and modifications may be practiced thereto, without departing from the spirit of the invention and the scope of the appended claims.

Claims (30)

1. CLAIMS 1. A clamp for rigid but releasable clamping for an article having a portion for fastening of predetermined shape and size, the clamp comprises an elastic body having an opening that extends inside the body, the opening is dimensioned slightly smaller that the fastening portion, the clamp includes connecting means to which an external drawing force can be applied in one direction and magnitude, to cause the aperture to expand elastically enough to receive the fastening portion, thereby conforming to it releases the stretching force, the opening elastically rests on the portion to be held.
2. 2. The clamp according to claim 1, characterized in that the body has a dimension in a first orthogonal direction that is substantially smaller than the dimensions in any of the other two orthogonal directions, and wherein the connecting means are placed to allow the opening to expand in a direction perpendicular to the first orthogonal direction.
3. 3. The clamp according to claim 2, characterized in that the opening extends through the body in a direction perpendicular to the first orthogonal direction.
4. 4. The clamp according to claim 3, characterized in that the article comprises an elongated flat strip having a portion on its length that defines the portion for fastening, and wherein the opening is dimensioned to allow passage of the portion for fastening through the aperture, only when the aperture is elastically expanded in a direction perpendicular to both the thickness and length direction of the band.
5. 5. - The clamp according to claim 4, characterized in that the opening is of a width, measured in parallel to the first orthogonal direction, sufficient to receive at least two thicknesses of the band, with which the band can be passed through of the opening, with respect to a second article and back through the opening to hold onto the second article.
6. 6. The clamp according to claim 5, characterized in that the band is of uniform width and thickness over substantially its entire length.
7. 7. - The clamp according to claim 6, characterized in that the band is in an enlarged portion at an end that restricts the end of passage through the opening when the opening is enlarged.
8. 8. A clamp for rigidly but releasably holding an elongated band, a length of the band has a predetermined cross-sectional size and configuration, the clamp comprises a body formed at least in part of superelastic alloy and having an aperture which extends through the body, the opening is dimensioned slightly smaller than the cross-sectional size of the band, the clamp includes connection means to which an external stretching force can be applied in one direction and magnitude to cause the The opening expands elastically enough to receive the strip length, so that as the stretching force is released, the aperture contracts elastically to its initial size to hold onto the band.
9. 9. - The clamp according to claim 8, characterized in that the opening is of a width, measured in parallel to the first orthogonal direction, sufficient to receive two thicknesses of the band, with which the band can be passed through the opening, with respect to an object to be held, and back through the opening to hold onto the object.
10. 10. - The clamp according to claim 2, characterized in that the opening extends through the body in a direction parallel to the first orthogonal direction.
11. 11. - The clamp according to claim 10, characterized in that the article has a pair of arms that have end portions that define portions for fastening, the end portions are spaced a distance that allows them to both be received into the opening only when the opening is elastically expanded in a direction perpendicular to the first orthogonal direction, thereby releasing the stretching force, the end portions of arms are locked in the opening.
12. 12. - The clamp of any of claims 1 to 11, characterized in that the body of the clamp is formed at least in part super elastic alloy.
13. 13. - The clamp according to claim 1, characterized in that it includes an instrument for applying the stretching force external to the body, the instrument comprises a pair of elongated members each having a handle portion backward, the instrument has a front portion including two arms, each arm has fastening means, to hold the connecting means of the body of the clamp, such that before divergence of the arms the clamp is stretched in the direction of arm divergence, the elongated portions of the instrument include interacting mechanical articulation means that force the arms to diverge in response to compression of the handle portions with respect to each other.
14. 14. - An instrument for imparting a stretching force for a stretchable clamp, the instrument comprises a pair of elongated members each having a handle portion rearwardly, the instrument has a front portion that includes two arms, each arm has means of clamping, for the clamp such that before divergence of the arms, the clamp is stretched in the diverging direction of arms, the elongated portions of the instrument include interacting mechanical articulating means which force the arms to diverge in response to understanding of the handle portions together.
15. 15. - The instrument according to claim 14, characterized in that one of the elongated members ends forward in the pair of arms, and wherein the mechanical articulation means comprise means for camming the arms apart in response to compression of the arms. the handle portions to each other.
16. 16. The instrument according to claim 15, characterized in that the mechanical articulation means comprise an oval opening formed in the elongated element between the arms, and an oval cam carried by the other elongate element for articulation in the oval opening.
17. 17. Method for fastening by clamps an article having a portion for fastening of predetermined shape and size, characterized in that it comprises: a) providing a clamp comprising an elastically deformable body having an aperture dimensioned slightly smaller than the portion for fastening , b) applying a stretching force to the body to elastically increase the size of the opening, such that it will receive the portion to be held, c) receive the portion to be held in the opening and d) release the stretching force.
18. 18. - The method according to claim 17, characterized in that the article is an elongated band for clamping an object, the method includes the step of passing the band through the opening, around the object and back to through the opening before releasing the stretching force.
19. 19. - The method according to claim 18, characterized in that the band is formed of a super elastic alloy, the method includes the step of stretching the band to deform elastically and keep the band in its stretched orientation, while releasing the Stretching force on the body.
20. 20. The method according to claim 17, wherein the article is a pedicle screw that has a pair of arms that form a yoke that receives a support rod, the method includes the step of receiving ends of both arms of the Pedicle screw through the opening before releasing the stretching force.
21. 21. The method according to claim 17, characterized in that the article is an external fixation device that has percutaneous pins and support rods to which the pins are to be connected, the rods and fasteners have the portions to hold, the method includes the step of receiving the portions to be held within the opening before releasing the drawing force.
22. 22. The method according to claim 17, characterized in that the article is a joint prosthesis having an increase, the increase and the prosthesis have clamped portions, the method includes the step of receiving the clamped portions within the aperture, before releasing the stretching force.
23. 23. - The method according to any of claims 17 to 22, characterized in that the clamp is formed at least in part from a super elastic alloy.
24. 24. Method for fastening by clamps an article having a portion for fastening of predetermined size and shape, characterized in that it comprises: a) providing a clamp comprising a body formed at least in part of a super elastic alloy and having an opening dimensional slightly smaller than the portion to hold; b) applying a stretching force to the body to deform the body beyond the region of Hooke's law, to elastically increase the size of the opening such that it receives the portion to be held, c) receive the portion to be held in the opening and d) releasing the stretch portion.
25. 25. In combination, a device comprising an article having a portion for fastening with a first section of predetermined shape and size, and a clamp for clamping rigidly but releasably to the article, the clamp comprises an elastic body that has an opening projecting within the body, the opening is dimensioned slightly smaller than the first section to hold the holding portion, the clamp includes connection means to which an external external force can be applied in a direction and amount for cause the opening to expand elastically enough to receive the portion to hold, so that as the stretching force is released, the opening elastically rests on the portion to be held.
26. 26. The equipment according to claim 25, characterized in that the fastening portion includes a second section spaced from the first section and sized smaller than the first section for reception in the clamp opening, and means defining a ramp between the first and second sections, configured to allow the clamp to be forced up the ramp from the second section to the first section, with concurrent elastic expansion of the clamp.
27. 27. The equipment according to claim 26, characterized in that the fastening portion comprises a wedge having a surface that abuts a portion of the article and has an outer surface defining the ramp.
28. 28.- A clamping device with band, characterized in that it comprises a clamp having a body formed at least in part of super elastic alloy and having an opening that extends through the body, an elongated band includes a first portion having a cross-sectional configuration slightly larger than the opening in the clamp and a second portion having a cross-sectional configuration slightly smaller than the opening in the clamp, and one. intermediate portion having a tapered sliding surface between the first and second portions configured to allow the clamp to be forced onto the tapered sliding surface of the second section to the first section, with concurrent elastic expansion of the clamp, thereby, As the force displacing the clamp is released on the sliding surface, the opening clamps elastically on the band.
29. 29. A fastening device by band clamp, characterized in that it comprises a clamp having an elastic body with an opening that extends through the body, a band configured to fit through the opening in the clamp body, and an elongated clamp lock having a surface configured to hold the portion of the strap and an opposite sliding surface configured to engage the opening in the clamp and over which the clamp can slide, the clip lock has an end configured for received in the clamp opening and a second end slightly larger than the opening of the clamp, whereby as the clamp is forced onto the sliding surface from one end of the clamp lock to the second end, the clamp expands elastically and when the force that displaces the clamp on the sliding surface is released, the embrace The clamp lock on the band was elastically clamped.
30. 30. Method for clamping one to an article such as bone, characterized in that it comprises: a) providing a clamp comprising an elastically deformable body having an opening b) applying to an elongated band an elongate clamp lock that has a surface holding the band and an opposite sliding surface, configured to engage the opening in the clamp and on which it can slide to the clamp, the clamp lock has one end configured to be received in the clamp opening and a second end slightly larger than the clamp opening, c) applying force to the clamp to move it over the sliding surface from the first end of the clamp lock towards the second end with concurrent elastic expansion of the clamp opening, and d) when releasing the clamp opening. force, the clamp elastically restrains the clamp lock on the band.