Abstract:
Apparatus and method used to reduce the movement between vertebrae or fractured bones. The implantable device can be deformed from its shape-set configuration for ease of deployment and return to a pre-set shape upon completion of deployment. The apparatus can serve to stabilize fractured bones or as a distraction device and support structure between vertebrae. Device may be made of a material with shape memory and superelastic properties which facilitate the method of implantation. The pre-set shape of the device may include dimensions/geometries which are similar to the natural curvature of the human spine or bone without the use of hinging or connection between multiple pieces. Once deployed, the device can serve to constrain the flow of bone growth material between the inside and outside of the device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation-In-Part of U.S. patent application Ser. No. 13/964,039 filed Aug. 10, 2013, which claims the benefit of priority to U.S. Provisional Patent Application 61/682,282 filed Aug. 12, 2012, and priority benefit is claimed for all common subject matter thereof. The benefit of priority is further claimed, for all common subject matter, to U.S. Provisional Patent Application 61/837,703 filed Jun. 21, 2013. The benefit of priority is further claimed, for all common subject matter, to U.S. Provisional Patent Application 61/725,030 filed Nov. 12, 2012. Each of which are incorporated herein by reference in their entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
     Not Applicable 
     FIELD OF THE INVENTION 
     The application relates to orthopedics and more particularly to bone fixation and spinal fusion devices and methods of implanting them. 
     BACKGROUND OF THE INVENTION 
     Fractured bones are among the most common orthopedic problem; about 6.8 million come to medical attention each year in the United States. Degenerative disc disease resulting in spine fusions has increased significantly and now represents approximately ½ million surgeries annually. The implantation of internal fixation or fusion devices can often be traumatic. If insufficient stabilization or incorrect anatomical alignment occurs, then revision surgery or on-going pain may be experienced by the patient. 
     There is a need for minimally invasive fracture fixation and spine fusion devices that can provide adequate stability through the use of screws and barbs, while maintaining a natural anatomical alignment during the healing process. If bone growth material is used, then the implant should limit the migration of this material from the fracture or fusion site. 
     Intramedullary nail devices using temperature effect to insert and fix a device in a bone are disclosed in U.S. Patent Application Publication No. 2010/0241120 to Bledsoe and U.S. Pat. No. 7,695,471 to Cheung et al. The Bledsoe device allows coolant to pass through the implant and into the body via the fracture, which can potentially flush away osteoblast. Osteoblast is believed to promote or accelerate the healing process and by flushing it away there may be a detrimental impact to the healing process. Cheung et al includes bone fixation without using other fastening elements but does not provide a method for maintaining the device in a chilled martensitic phase during implantation. 
     Minimally invasive interbody spine fusion devices that are introduced in a relatively straight configuration and form a curved configuration within the disc space have been disclosed. One generalized patent to limit the movement of flowable material introduced into or between tissue layers of the human spine U.S. patent application Ser. No. 07/666,227 Benvenue Medical, Inc. (Inventor, Laurent Schaller) The Schaller device prevents or substantially limits the movement of flowable material into vertebral material. However this device does not define any means for mechanical fixation. 
     In U.S. Pat. No. 8,206,423 Siegal et al has devised a device that utilizes hinges to allow deflection of each segment relative to adjacent segment, the device has a physical geometry which has an elongated element in the fully flexed state and a predefined curved configuration. However, this device defines an external method for delivery of osteogenic material. 
     Other attempts such as U.S. Pat. No. 8,162,942 focus on fixation barbs and other partial solutions, but have limited applicability and still fail to provide a truly minimally invasive approach, due to the device requiring installation through the joint surface which can result in long term degeneration of the joint surface. All previous attempts have failed to provide a complete solution, but have instead addressed only minimally invasive fixation, anatomical alignment, or the containment of bone growth material, and not all three. Solutions have been long sought but prior developments have not taught or suggested any solutions, and thus, solutions to these problems have long eluded those skilled in the art. 
     SUMMARY OF THE INVENTION 
     The claimed invention is directed to systems and methods for fixating or fusing bones that have an original shape that can be configured to deform into shapes that have circumferential lengths that remain substantially unchanged, and when inserted into the body returns to an original shape that matches the anatomy. Among the many different possibilities contemplated, one embodiment includes an implant which contains barbs or screws to minimize the possible migration of the implant and to provide added structural rigidity during the bone healing process. 
     Another embodiment of the invention includes an interbody spinal fusion device generally used for degenerative disc issues and for fusing vertebra together comprising a tubular member made of shape memory material. In one example, the tubular member and projections can comprise super-elastic material such as nitinol having an austenite start (As) temperature of about 5° C. and an austenite finish (Af) temperature of about 30° C. 
     Another embodiment may also contain open features on the inner annular surface. These open features permit bone graft or other bone growth material to be delivered down the longitudinal axis of the tubular construction and introduced into the center region while constraining the bone growth material from flowing to undesirable areas. 
     Other embodiments of the invention provide benefits that include the ability to match anatomical angles and curvatures. 
     An alternate embodiment can be comprised of a tubular implant made of a shape memory material that when chilled is maintained in a flexible state for insertion into a desired location within the body and when warmed to approximately body temperature has a rigid state, which allows the implant to provide adequate fixation. 
     The present invention further includes objects, features, aspects, and advantages in addition to or in place of those mentioned above. These objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like reference numerals are intended to refer to like components, and in which: 
         FIG. 1  is an isometric view of an implant system in a first embodiment of the present invention and in an original shape. 
         FIG. 2  is a cross-sectional view of the implant system of  FIG. 1  along the line  2 - 2 . 
         FIG. 3  is a cross-sectional view of the implant system of  FIG. 1  along the line  3 - 3 . 
         FIG. 4  is an isometric view of the implant system of  FIG. 1  in a deformed shape. 
         FIG. 5  is an isometric view of the implant system of  FIG. 1  during a loading step of use. 
         FIG. 6  is a schematic view of a retention belt for use with an embodiment of the present invention. 
         FIG. 7  is an isometric view of an implant system in a second embodiment of the present invention and in a partially deformed shape. 
         FIG. 8  is an isometric view of an implant system in a third embodiment of the present invention and in a deformed shape. 
         FIG. 9  is an isometric view of an implant system of  FIG. 8  in an original shape. 
         FIG. 10  is an isometric view of the implant system in a fourth embodiment of the present invention during a loading step of use. 
         FIG. 11  is an isometric view of a guide-wire for use with an embodiment of the present invention. 
         FIG. 12  is an isometric view of an implant system in a fifth embodiment of the present invention and in an original shape during an osteogenic material injection step of use. 
         FIG. 13  is an isometric view of an implant system in a sixth embodiment of the present invention and in a partially deformed shape during an insertion step of use. 
         FIG. 14  is an isometric view of an implant system in a seventh embodiment of the present invention and in an original shape. 
         FIG. 15  is an isometric view of an implant system in an eighth embodiment of the present invention and in a deformed shape. 
         FIG. 16  is an isometric view of the implant system of  FIG. 15  in an original shape. 
         FIG. 17  is an isometric view of an implant system in a ninth embodiment of the present invention and in a partially deformed shape. 
         FIG. 18  is an isometric view of an implant system in a tenth embodiment of the present invention and in an original shape. 
         FIG. 19  is a side view of a mandrel for use with an embodiment of the present invention. 
         FIG. 20  is a side view of the implant system of  FIG. 18  before an insertion step of use. 
         FIG. 21  is a side view of the implant system of  FIG. 18  during an insertion step of use. 
         FIG. 22  is a side view of the implant system of  FIG. 18  after an insertion step of use. 
         FIG. 23  is a side view of the implant system of  FIG. 18  after an installation step of use. 
         FIG. 24  is a flow chart of a method of use of the implant system for a spine fusion embodiment of the present invention. 
         FIG. 25  is a flow chart of a method of use of the implant system for a fracture fixation embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration, preferred embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     The following preferred embodiments disclose an implant system implemented within various (elements used) for clarity and descriptive convenience. The implant system is described in sufficient detail to enable those skilled in the art to make and use the invention and provide numerous specific details to give a thorough understanding of the invention; however, it will be apparent that the invention may be practiced without these specific details. 
     In order to avoid obscuring the present invention, some well-known system configurations are not disclosed in detail. Likewise, the drawings showing embodiments of the system are semi-diagrammatic and not to scale and, particularly, some of the dimensions are for the clarity of presentation and are shown greatly exaggerated in the drawing FIGs. Generally, the invention can be operated in any orientation. 
     As used herein, the term “superior” is defined as above. The term “inferior” is defined as below. The term “nitinol” is defined as a shape memory and super-elastic metal. The term “austenitic” is defined as the rigid phase for nitinol. The term “martensitic” is defined as the soft or malleable phase for nitinol. The term “osteogenic” is defined as bone tissue formation. The term “lordosis” is defined as the inward curvature of a portion of the lumbar and cervical vertebral column. 
     The invention generally involves bone fixation or spinal fusion apparatuses that use super-elasticity or pseudo-elasticity and/or shape memory effect for bone fracture fixation or spinal fusion. A shape memory material such as a nickel titanium alloy material or nitinol can be used to provide these properties. 
     According to one embodiment of the invention, a nitinol implant system  1700  is treated thermally and mechanically such that it has one predetermined memory set shape. The implant system can be provided with one-way shape memory such that it can undergo deformation at a relatively cool temperature and then recover its preset memory shape upon heating above its austenite finish transformation temperature without requiring external mechanical forces. In a second embodiment, the implant system can be provided with two-way shape memory where the device has a shape that is reversible upon return of the temperature. 
     In a third embodiment, the implant system  400 / 2000  may rely on the materials super-elastic properties. For embodiments incorporating the use of super-elastic properties, the implant system is deformed and constrained in the deformed shape using a rigid mandrel. The rigid mandrel may be comprised of a rod or tube. The preferred embodiment would be comprised with the rigid mandrel tube being sized to fit within the inner diameter of the implant system. The inner diameter of the rigid mandrel tube being sized to fit over a guide wire. 
     According to one embodiment of the invention, the implant system  1700  can have a memory shape to which it returns when, for example, its temperature is increased to about an average body temperature after having been cooled below its austenite start temperature. The implant system for example, can be designed so that when cooled below about 5° C. it is in its martensitic state and when warmed above about 30° C. it returns to its austenitic state and preset memory set shape without requiring external mechanical forces. When cooled to its martensitic state, it is readily malleable and flexible, for introduction into the body. After the device is in its desired position, it is no longer cooled so that it can warm to the patient&#39;s body temperature (e.g., above 30° C.) where the device returns to its austenitic state and its memory set shape. It is more rigid in the austenitic state and provides stable support. 
     The implant system  1800  can be, for example, an intramedullary fixation device. It can be sized and configured to treat various fractured bones. For example, it can be sized and configured to treat a fractured humerus, radius, ulna, tibial, femeral or clavicle bone. In one embodiment, it is introduced through a bony projection of the bone. For example, in the case of the humerus bone, it can be bent to accommodate a curved bore made through the epicondyle or greater tuberocity, and then advanced into the intramedullay canal. Among the many advantages of this approach is that it reduces surgical trauma as compared to introducing the device at the end of the treated bone, potentially compromising the joint surface. Typically, the implant system would have a memory set configuration that aligns with the medullary canal. For the femeral and tibial bones, the memory set shape is relatively straight while for other bones like the clavicle it may have a curve that aligns with the anatomical shape of the medullary canal. 
     The implant system  100  can be deformed into a deformed shape  112  of  FIG. 4  having a circumferential length  107  of  FIG. 4 . The circumferential length  107  of the deformed shape  112  should be substantially similar to the circumferential length  108  of  FIG. 2  of the original shape  104  of  FIG. 1 . For the purposes of this application a substantially similar circumferential length is defined as a circumferential length between the deformed shape  112  and original shape  104  of no more than a factor of 1.5. 
     The circumferential length  107  of the deformed shape  112  and the circumferential length  108  of the original shape  104  can vary for example when the implant system  104  is loaded onto a mandrel  113  of  FIG. 4 . The mandrel  113  can cause the implant system  104  to deform and slightly increase the circumferential length  107  of the deformed shape  112 ; however, it should be noted that the increase in the circumferential length  107  of the deformed shape  112  by the mandrel  113  is not substantially different but is substantially similar to the circumferential length  108  of the original shape  104 . 
     The implant may be manufactured from a porous shape memory material. The benefit of the porous material is that it permits osteo-integration. Other means of achieving osteo integration by coating the implant with hydroxyapatite-(HA) or other bio-compatible coatings that promote osteo integration is also contemplated. 
     Referring now to  FIG. 1 , therein is shown an isometric view of an implant system  100  in a first embodiment of the present invention and in an original shape  104 . In this embodiment, the implant has barbs  102  that extend radially outward from a main body  103  of the implant system  100 . The main body  103  of the implant systems  100  for spine fusion will typically take on a general “p” shape configuration when in the original shape  104 . The center  106  of the “p” configuration can act as a receptacle for bone graft or other osteogenic material. This receptacle region provides the benefit of containing or limiting the migration of the osteogenic material. 
     Referring now to  FIG. 2 , therein is shown a cross-sectional view of the implant system  100  of  FIG. 1  along the line  2 - 2 . This cross-section shows how the original shape  104  of  FIG. 1  of the implant system  100  has been set such that it forms an ellipse  108  with the major axis in the horizontal plane and the minor axis in the vertical plane. 
     Referring now to  FIG. 3 , therein is shown a cross-sectional view of the implant system  100  of  FIG. 1  along the line  3 - 3 . This cross-section demonstrates how the implant system&#39;s  100  original shape  104  of  FIG. 1  can be formed to have a lateral angle  110  similar to the anatomical angle of the disc between two adjacent vertebrae. By having the original shape  104  of the implant system  100  that mimics the disc anatomical angle it provides the benefit of being able to adjust the spine angle for people who are affected by lordosis. 
     Referring now to  FIG. 4 , therein is shown an isometric view of the implant system  100  of  FIG. 1  in a deformed shape  112 . Relying on the super-elastic properties of the material, the main body  103  of the implant system  100  can be deformed, the deformed shape  112  can include a relatively straight shape. Belts  114  can be used to constrain the barbs  102  in the deformed shape  112 , which includes a retracted state which aids in the delivery of the implant system  100  into the body. 
     Referring now to  FIG. 5 , therein is shown an isometric view of the implant system  100  of  FIG. 1  during a loading step of use. As the implant is off-loaded from the mandrel  113 , the implant system  100  begins to return to its original shape  104  without requiring external mechanical forces and is shown in a partially deformed shape  116 . 
     Referring now to  FIG. 6 , therein is shown a schematic view of a retention belt system  600  for use with an embodiment of the present invention. The belt system  600  of this design may be used to constrain the barbs  102  of  FIG. 1  in the deformed shape  112  when the barbs  102  are retracted. Upon withdrawing a release wire  118 , the belt system  600  is released permitting the barbs  102  to extend radially outward in their original shape  104  without requiring external mechanical forces. After the belts have been released and the barbs have extended radially outward, the belt system  600  may be removed from the implant system by withdrawing the belt cable  120 . 
     Referring now to  FIG. 7 , therein is shown an isometric view of an implant system  700  in a second embodiment of the present invention and in the partially deformed shape  116 . In this FIG. the belts  114  are shown in an alternate configuration that is on the outside of the implant system  700  rather than within the lumen of the implant system  100  of  FIG. 1 . The implant system  700  has been partially deployed to the point where the receptacle  106  for osteogenic material has been formed. 
     Referring now to  FIG. 8 , therein is shown an isometric view of an implant system  800  in a third embodiment of the present invention and in the deformed shape  112 . In this embodiment, the belts  114  of  FIG. 1  used for retaining the barbs  102  have been replaced by a banded sleeve  117 . The banded sleeve  117  can be positioned with bands over the barbs  102  to constrain them in the deformed shape  112  and being retracted for ease of insertion into the desired location. 
     Referring now to  FIG. 9 , therein is shown an isometric view of an implant system  800  of  FIG. 8  in an original shape  104 . This FIG. illustrates the banded sleeve  117  in an alternate position with the bands of the banded sleeve  117  positioned off the barbs  102 . With the bands not constraining the barbs  102 , the barbs  102  are free to expand radially to their original shape  104 , thus providing fixation of the implant system  800 . Additionally, tabs  118  with holes  120  that are sized to accept bone screws may return to their original shape  104 . 
     Referring now to  FIG. 10 , therein is shown an isometric view of the implant system  1000  in a fourth embodiment of the present invention during a loading step of use. This FIG. demonstrates the use of a ratcheting mechanism  122  that can be used to off-load the implant system  1000  from a mandrel  124 . As with other embodiments, including implant systems  700  and  800 , the ratcheting mechanism  122  may be incorporated. An alternate off-loading mechanism may include a linear screw which is not shown. 
       FIG. 10  also illustrates the use of the mandrel  124  such as a guide wire mandrel that can provide directional guidance of the implant system  1000  assuming the implant system  1000  has been chilled and is in malleable martensitic state. The chilling method is further illustrated in  FIG. 17 . 
     Referring now to  FIG. 11 , therein is shown an isometric view of the mandrel  124  for use with an embodiment of the present invention. This mandrel  124  may be made of nitinol or other shape memory material. To maintain rigidity of the mandrel  124  the autenetic finish (Af) temperature of this component should be maintained below the temperature of the chilling fluid. Adjustments to the Af temperature can be achieved and is known to those skilled in the art. 
     Referring now to  FIG. 12 , therein is shown an isometric view of an implant system  1200  in a fifth embodiment of the present invention and in the original shape  104  during an osteogenic material injection step of use. This FIG illustrates one possible method of injecting osteogenic material into the center  106  or receptacle region. By using a flexible syringe  128 . The end of the flexible syringe  129  can be sent through a port  126  that has been designed into the implant system  1200 . Assuming the barrel of the flexible syringe  129  has been filled with osteogenic material, it can be injected into the receptacle region or the center  106  using the plunger  130 . Additionally, bone screws  132  can be installed through the tabs  118  and into the superior and inferior vertebrae. The benefit of the flexible syringe  129  is that it permits directing the osteogenic material to desired locations. The addition of bone screws  132  can prove beneficial for providing increased rigidity and fixation. 
     Referring now to  FIG. 13 , therein is shown an isometric view of an implant system  1300  in a sixth embodiment of the present invention and in the partially deformed shape  116  during an insertion step of use. This FIG illustrates the approach where the osteogenic material  134  has been placed prior to the introduction of the implant system  1300 . The implant system  1300  can then wrap around the osteogenic material thus minimizing any migration of the said material. 
     Referring now to  FIG. 14 , therein is shown an isometric view of an implant system  1400  in a seventh embodiment of the present invention and in the original shape  104 . This FIG. illustrates how wires  136  or other semi-rigid material can be placed within the center lumen of the implant system  1400  to provide the added benefit of minimizing any compression of the implant when bending or compressive loads are applied. Alternatives to the wires  136  that can provide compressive rigidity to the implant system  1400  include rods or bone cement PMMA (polymethyl methacrylate). A cap  138  may be installed onto the end of the implant system  1400  to minimize the migration of any rigid filler material and to act as a fixation element for the bone screws  132  of  FIG. 12  that may be placed into the superior and inferior vertebrae. 
     Referring now to  FIG. 15 , therein is shown an isometric view of an implant system  1500  in an eighth embodiment of the present invention and in the deformed shape  112 . This FIG. illustrates how an implant system  1500  may be deformed in the vertical plane  140  to reduce the profile of the implant system  1500  such that it may be introduced into areas with minimal vertical accessibility. 
     Referring now to  FIG. 16 , therein is shown an isometric view of the implant system  1500  of  FIG. 15  in the original shape  104 . This FIG. illustrates the implant systems&#39;  1500  return to its original profile  142  without requiring external mechanical forces, where the height of the original profile  142  is greater than the height of a profile of the deformed shape  112  of  FIG. 15  deformed in the vertical plane  140  of  FIG. 15  and thus providing the benefit of distraction or separating force between adjacent vertebrae. 
     Referring now to  FIG. 17 , therein is shown an isometric view of an implant system  1700  in a ninth embodiment of the present invention and in the partially deformed shape  116 . This FIG. illustrates the embodiment where a chilled fluid reservoir  150  can be circulated through the implant system  1700  to maintain the implant system  1700  in a flexible martensitic phase. Although one suitable fluid source (the fluid reservoir  150 ) and pump  148  for chilling the implant system  1700  is diagrammatically shown, it should be understood that other mechanisms for circulating fluid through the implant system can be used. Thus, the fluid reservoir  150  can be a bag (e.g., I.V. like bag) of chilled sterile saline that is placed in an ice bath. Once the saline is sufficiently cool, a standard I.V. plastic tube  149  would be used to connect it to flush port  146 . The pump  148  can be a peristaltic pump located outside the fluid reservoir  150  and once turned on it would create a suction pulling chilled fluid from the fluid reservoir  150  typically a sterile bag of saline, through the pump and out to the implant system  1700 . The pump  148  would be clamped onto the plastic tube  149  and when turned on, fluid would be transferred from the bag or the fluid reservoir  150 , through the plastic tube  149  and into the implant system  1700 . 
     A sheath  144  with the attached flush port  146  constrains the chilled fluid around the implant system  1700 . The sheath  144  also acts in a beneficial function as a constraint to maintain the barbs  102  in a retracted state. In this manner, a cooling fluid can be circulated in the implant system  1700  during insertion so that the implant system  1700  remains flexible throughout the insertion process and the barbs  102  do not prematurely move to their memory shape configuration (the original shape  104  of  FIG. 1 ) and anchor the implant system  1700  before it is in position. The sheath  144  also provides a smooth surface for insertion and can be readily withdrawn after the implant system  1700  is in the desired position. 
     Once the implant system  1700  has been properly positioned, the pump  148  may be turned off and the sheath  144  removed, thus permitting the implant system  1700  to warm to body temperature (approximately 37° C.). The implant system&#39;s austenitic finish temperature Af should be processed so that it remains below body temperature and thus the implant becomes structurally rigid. 
     Referring now to  FIG. 18 , therein is shown an isometric view of an implant system  1800  in a tenth embodiment of the present invention and in the original shape  104 . This FIG. illustrates one preferred embodiment for a fracture fixation device. The implant system  1800  may have a curved end  154  which allows access to the medullary canal for certain long bones without disturbing a joint surface. However, the curved end  154  is not provided on all designs. According to another embodiment, the bone fixation device can have a straight shape without the curved end  154  when being used in an ulna bone. In a further embodiment, the bone fixation device can have an S-shape without the curved end  154  when being used in a clavicle. Transverse holes  156  may be designed into the implant system  1800  for the placement of bone screws. 
     The implant system  1800  may also be designed to have a radius of curvature  158  that mimics the anatomy of the fractured bone. Since many bones within the body have one or more curvatures, in one or more planes, the benefit of this embodiment is that the implant system  1800  may be inserted into the bone without distorting or applying undue stress to the bone. 
     In addition, the implant system  1800  is made from a tubular construct; it may be used in conjunction with a guide wire. A conical tip  160  may be designed into the implant system  1800  to act as an aid for inserting the implant into the medullary canal of the bone and across the fracture site. 
     Referring now to  FIG. 19 , therein is shown a side view of a mandrel  161  for use with an embodiment of the present invention. The mandrel  161  is illustrated with a curved tip  162 . The curved tip  162  allows for accessing the medullary canal of the bone via the side of the bone. The benefit of accessing the medullary canal from the side is that it eliminates the need to excise the joint surface which can increase the patient&#39;s risk of developing arthritis. The mandrel  161  may also contain a ratcheting handle  164  or other means, including a linear screw, to mechanically transfer the implant system  1800  from the mandrel  161  into the medullary canal. 
     Referring now to  FIG. 20 , therein is shown a side view of the implant system  2000  of  FIG. 18  before an insertion step of use. This FIG. illustrates the implant system  2000  that may be deformed and loaded onto a mandrel  161 . A curved access hole  166  may be prepared within the fractured bone providing access to the medullary canal  168 . A guide wire  170  may be inserted into the medullary canal  168  and the implant system  2000  and the mandrel  161  may be threaded over the guide wire  170 . 
     Referring now to  FIG. 21 , therein is shown a side view of the implant system  1800  of  FIG. 18  during an insertion step of use. This FIG. illustrates how the implant system  1800  has been partially off-loaded from the mandrel  161 . As the implant system  1800  is transitioned off the mandrel  161 , the part  172  of the implant system  1800  that is not in contact with the mandrel  161  is shown returning to its original shape  104  without requiring external mechanical forces. 
     Referring now to  FIG. 22 , therein is shown a side view of the implant system  1800  of  FIG. 18  after an insertion step of use. This FIG. illustrates how the implant system  1800  has been fully advanced into the medullary canal  168 . The implant system  1800  has returned to its original shape  104  having the curvature  158  that matches the anatomical shape of the fractured bone. At this point the guide wire  170  of  FIG. 21  and mandrel  161  may be removed. 
     Referring now to  FIG. 23 , therein is shown a side view of the implant system  1800  of  FIG. 18  after the installation process. Illustrated in this FIG. is the use of transverse bone screws  174  that fixate the implant system  1800  within the medullary canal  168  and thus providing the benefit of creating a rigid scaffold during the bone healing process. 
     Referring now to  FIG. 24 , therein is shown a flow chart of a method of use of the implant system for a spine fusion embodiment of the present invention. This flow chart is a descriptive explanation of the installation procedure for spine fusion. In the first step  2400 , access is gained to the vertebral disc and the nucleus pulposus (center disc material) is evacuated to provide space for the implant. In the second step  2410 , an implant that has been loaded onto a mandrel is inserted into the disc space and using either a ratchet, linear screw, or other mechanical means, the implant is off-loaded from the mandrel where the implant returns to its original configuration. In the third step  2420 , barb constraints (belts/sleeves/or other mechanical means) are removed thus allowing the barbs to engage into the superior and inferior vertebrae. In the fourth step  2430 , bones screws may be installed into the superior and inferior vertebrae providing additional fixation. In the fifth step  2440 , osteogenic material including autograft, allograft, or bone morphogenic protein (BMP) can be injected or inserted into the center receptacle region of the implant. In the sixth step  2450 , wires, a rod, bone cement, or other structurally rigid filler material is placed within the center lumen of the implant. This filler material increases the compressive strength of the implant when anatomical loads are applied. In the seventh step  2460 , the access to the vertebral disc is closed and if deemed necessary, additional fixation such as pedicle screws with rods may be installed. 
     Referring now to  FIG. 25 , therein is shown a flow chart of a method of use of the implant system for a fracture fixation embodiment of the present invention. This flow chart is a descriptive explanation of the installation procedure for fracture fixation. In the first step  2500 , access to the medullary canal via a boney protrusion is obtained. Most often this access is obtained by creating a curved access path using a cutting tool that has radius of curvature similar to the curved end  154  of the implant. In the second step  2510 , a guide wire is inserted into the access hole and advanced across the fracture site. In the third step  2520 , the medullary canal may be reamed to ensure the implant fits within the canal. In the fourth step  2530 , the implant system is inserted at the access site and off-loaded from the rigid mandrel. In the fifth step  2540 , the guide wire is removed and transverse bone screws may be installed to provide bone fixation. In the sixth step  2550 , the access site is closed and a cast or other stabilization method is used during the healing process. 
     Thus, it has been discovered that the implant system of the present invention furnish important and heretofore unknown and unavailable solutions, capabilities, and functional aspects. 
     The resulting configurations are straightforward, cost-effective, uncomplicated, highly versatile, accurate, sensitive, and effective, and may be implemented by adapting known components for ready, efficient, and economical manufacturing, application, and utilization. 
     While the invention has been described in conjunction with a specific best mode, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the preceding description. 
     Accordingly, it is intended to embrace all such alternatives, modifications, and variations, which fall within the scope of the included claims. All matters set forth herein or shown in the accompanying drawings are to be interpreted in an illustrative and non-limiting sense.