Patent Application
20200046345
The present invention relates to a variable compression bone staple used for the fixation of bone of the musculoskeletal system. More specifically, the invention relates to a bone staple which creates compression in the fractured area of the damaged bone once the bone staple is implanted, and which includes anti-migratory structure for preventing the bone staple from detaching from the bone once implanted. Further, the invention also discloses an insertion device for installing the bone staple in the bone in a precise and timely manner.
Bone staples have been in clinical use for decades and are used in many applications in orthopedics. More specifically, bone staples are generally used to compress broken bone end joints to allow for the fusion of one portion of the bone to another. Early embodiments of bone staples were rather crude and rigid, and comprised of stainless steel or cobalt-chromium U-shaped implants that were commonly hammered into the patient's bone.
Over time, these early bone staples evolved into more modern devices that could be manipulated to compress two adjacent bone segments together. Currently, bone staples are typically implanted by drilling holes into the bone and, upon installation of the bone staple, using heat and/or mechanical means to cause the bone staple to change shape and pull together or compress the damaged bone segments to begin the healing process. Unfortunately, the newer design of bone staple still suffers from a number of limitations. For example, the current bone staple still requires the surgeon to manually manipulate the bone staple while attempting to implant the same into the affected bone, which is both difficult and time consuming. Further, current bone staples, because of their design limitations, require complex and expensive instrumentation, thus impeding their usefulness. For example, if pliers or forceps are used to bend the bone staple to compress the bone segments, the elastic nature of the material that the bone staple is comprised of can cause the bone staple to partially return to its pre-bent shape. Thus, these bone staples may change shape or be manipulated to change shape but do not pull together and compress bone segments with a predictable amount of shape change and compression force.
Additional materials have been utilized to improve upon these deficiencies. For example, most bone staples used today are made of nickel-titanium alloy, or nitinol. Nitinol acquires compression through either the elastic nature of the material or through natural body heat. Nitinol has superior elastic properties, such that if the parallel legs of the bone staple are angled toward the center of the staple and then spread out to be inserted into the bone; the legs of the bone staple will spring back to the center once implanted. However, Nitinol is not an extremely strong or durable material, and it is difficult and, in some cases, impossible to control the amount of compression between the bone segments when using bone staples comprised of Nitinol. Another kind of Nitinol will change shape with ambient temperature. For example, once the Nitinol material reaches body temperature it will compress the legs of the bone staple inward to create compression between the broken ends of the bone. However, these heat sensitive staples are problematic because during implantation the staple can change shape. Furthermore, during shipping, costly strategies must be implemented to keep environmental heating from causing the staple to change shape prior to implantation. For example, strategies such as keeping the staple on dry ice were used to partially overcome this issue but it increased cost and caused the surgeon to have to work quickly in procedures where deliberate, detailed and time-consuming techniques are required to achieve a positive outcome.
Consequently, there is a long felt need in the art for a bone staple that is surgeon controlled and that produces a predictable and desired amount of shape change and compression force. Further, there is a need for a strong, durable bone staple that is also cost effective to manufacture, ship and implant, and that does not change shape prior to implantation causing the surgeon to have to work quickly. The present invention discloses a unique titanium alloy bone staple and integral insertion device that provides biocompatibility, increased strength, and cost effectiveness. The titanium alloy bone staple of the present invention does not materially change shape prior to its implantation, and is also surgeon controlled such that the amount of compression between the broken ends of the bone can be regulated directly by the surgeon.
The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed innovation. This summary is not an extensive overview, and it is not intended to identify key/critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
In one embodiment, the present invention comprises a unique bone staple that comprises a bridge component having two opposed ends, and a pair of spaced apart legs extending outwardly from either end of the bridge component. Each leg of the bone staple of the present invention further comprises a prong, tab, or protrusion at its proximal end near the bridge component and positioned on the outside or outboard surface of the leg for anti-migratory purposes. Each leg also comprises a tapered angle at a distal end or tip of the leg for compressing the bone segments together upon successful installation. More specifically, the bone staple is inserted into the fractured area of the bone, and secured to the bone segments to create compression forces between the bone segments to bring the segments together to fuse with one another during the healing process. Once implanted, the bridge component of the bone staple is positioned in the cortical bone, and the distal tips of the legs are positioned in the cancellous bone.
In a preferred embodiment of the present invention, an insertion device for installing the bone staple in the patient's bone is integral to the bone staple, and both are manufactured from a titanium alloy, specifically Ti 6 Al 4 V-ELI, though other suitable materials can also be used without affecting the overall concept of the present invention. In one embodiment, the insertion device comprises a pair of arm components with a drill guide component secured to the proximal end of each arm component. Thus, the drill guide components are integral to the inserter and comprise a plurality of serrations on the tip of the drill guides to help grab the bone and prevent slippage during the drilling procedure. Once the drill guides are used, the bone staple is inserted or implanted a desired depth into the bone. A surgeon can then open the insertion device by pulling apart or spreading the arm components to add compression forces to the bone staple. Therefore, the surgeon is able to control the amount of compressive force at the time of implantation of the bone staple. Once the required amount of compression is applied, and the bone staple is inserted in the desired depth into the bone, the insertion device is detached from the bone staple and removed.
To the accomplishment of the foregoing and related ends, certain illustrative aspects of the disclosed innovation are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles disclosed herein can be employed and is intended to include all such aspects and their equivalents. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings.
While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying FIGS., in which like reference numerals identify like elements, and wherein:
The innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding thereof. It may be evident, however, that the innovation can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate a description thereof.
Generally stated, the present invention relates to a titanium alloy bone staple and integral insertion device that provides biocompatibility, increased strength, and cost effectiveness. The titanium alloy bone staple does not change shape prior to implantation, and does not require the elaborate or expensive shipping or storage environments associated with prior art bone staples. Once the bone staple is inserted to the desired depth into the bone, the arms of the insertion device are spread apart to apply the desired amount of compression to the bone staple and, ultimately, to the bone segments. Then, the insertion device is detached from the bone staple and removed from the patient. In this manner, the amount of compression between the broken segments of the bone can be regulated directly by the surgeon. Further, anti-migration features on the bone staple prevent the bone staple from detaching from the bone.
Referring initially to the drawings,
The bone staple 102 is preferably comprised of a bridge component 106 and a pair of spaced apart legs 108 extending outwardly from the bridge component 106 and the bone staple system 100 overall. More specifically, a leg 108 is positioned at each end of bridge component 106, and extends outwardly therefrom for insertion into a patient's bone (not shown). As best shown in
Notwithstanding, one of ordinary skill in the art will appreciate that the shape and size of the bone staple 102, as shown in
As previously discussed, the bone staple 102 is preferably comprised of a titanium alloy, and most preferably of Ti 6 Al 4 V-ELI, though it is contemplated that other medical grade materials can also be used without affecting the overall concept of the present invention. More specifically, bone staple 102 is preferably laser cut from a single piece of titanium alloy, specifically Ti 6 Al 4 V-ELI, thereby lowering the cost of manufacturing bone staple 102. While laser cutting is the preferred method of manufacturing bone staple 102, other manufacturing techniques are also contemplated such as casting, molding, forming, additive manufacturing, etc. Similarly, it is also contemplated that the various components of the bone staple 102 could be manufactured separately and then joined together prior to use.
As best shown in
Each of the pair of arm components 117 are secured to a respective leg 108 of the bone staple 102 at a break-off point 119. Thus, once the bone staple 102 is implanted to the desired depth into the patient's bone, the insertion device 104 is moved up and down and/or rotated until the break-off points 119 weaken and break. In this manner, the insertion device 104 is separated from the bone staple 102 and removed from the patient.
Further, the arm components 117 also comprise a drill guide component 118 secured to the proximal end 120 of each arm component 117. Thus, the drill guide components 118 are integral to the insertion device 104. As best shown in
Notwithstanding, one of ordinary skill in the art will appreciate that the shape, size, and configuration of the insertion device 104, as shown in
The insertion device 104 is preferably laser cut from a single piece of titanium alloy, specifically Ti 6 Al 4 V-ELI, though other suitable materials can also be used without affecting the overall concept of the present invention. In a preferred embodiment, the insertion device 104 is integral to the bone staple 102, and both are manufactured from and laser cut from a single piece of titanium alloy, specifically Ti 6 Al 4 V-ELI. In another embodiment, the bone staple 102 and insertion device 104 of the present invention may be integrally manufactured using additive manufacturing techniques, or by using a combination of other molding or machining techniques (e.g., injection molding, machining, etc.) to produce the subject bone staple and insertion device. These additional techniques include, without limitation, material extrusion, vat photo polymerization, powder bed fusion, material jetting, binder jetting, sheet lamination and directed energy deposition, or any other suitable technique as is known in the art.
Having described a preferred embodiment of the bone staple system 100, its use will now be described in general terms. During surgical insertion of the bone staple system 100 into a patient (not shown), the bone staple 102 is inserted into the fractured area (osteotomy) of the bone and secured to the bone segments to create compression between the bone segments. Once implanted, the bridge component 106 of the bone staple 102 is positioned in the cortical bone and the distal tips 116 of the legs 108 are positioned in the cancellous bone. More specifically, and with the insertion device in a closed position as best illustrated in
Once the drill guide components 118 are used and the guide holes are created, the bone staple 102 is inserted (implanted) the desired depth into the bone either by surgeon force or by mallet or other instrument persuasion. As best shown in
Accordingly, the bone staple system 100 of the present invention delivers a bone staple 102 that is surgeon controlled and that produces a predictable and desired amount of shape change and compression force, along with anti-migratory features that prohibit the bone staple 102 from being inadvertently removed from the bone once implanted. Further, the durable bone staple 102 of the present invention is cost effective to manufacture, ship and implant, and does not change shape prior to implantation like other prior art bone staples. Additionally, the bone staple system 100 of the present invention further comprises an integrally formed insertion device 104 that permits the surgeon to quickly and precisely implant the bone staple 102, and then separate the insertion device 104 from the bone staple 102, and remove the same from the patient.
What has been described above includes examples of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the claimed subject matter are possible. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
