Patent Description:
Shape memory implants are commonly used in surgical procedures that require the reattachment or fusing of tissue or bone. Shape memory implants can be composed of shape memory material such as Nitinol that allows the shape memory implants to have a first final shape and the ability to transform into a second shape. A shape memory implant can be either thermally activated, in which an external heating source or body temperature would be required to activate the implant, or mechanically activated, in which a constraining instrument would be required. A shape memory implant that requires mechanical constraint stores mechanical energy due to elastic (recoverable) deformation, and then releases the stored mechanical energy when the constraint is removed. In these types of implants, the implants are mechanically deformed into their second shape and maintained in their second shape by instrumentation such that, upon release from the instrumentation, the implants elastically deform from their second shape into their first final shape.

In surgical procedures, the elastic property of constrained shape memory implants is used as follows. Bones that require fixating are aligned, and the shape memory implant, which has been mechanically deformed to its second shape, is maintained in instrumentation and inserted between the bones. In the second shape, the legs of the implant are generally parallel. After insertion, the shape memory implant is released from the instrumentation, whereupon the shape memory implant elastically returns to its first final shape such that the shape memory implant maintains the bones fixated together. In the first final shape, the legs of the implant are converging at the tips. Because the shape memory implant stores mechanical energy, it continuously applies force to the fixated bones as the shape memory implant transitions from the second shape to the first final shape, which aids in the healing process.

Various types of instrumentation can be used for either maintaining the shape memory implants in their second shape or moving an implant from its first final shape to a temporary second shape. Some companies used metal forceps to open and insert the shape memory implant. These forceps have to be sterilized by a hospital, and then a shape memory implant can be placed on the forceps, opened to a desired position, and used for inserting the implant. Although potentially effective, forceps require the implant to be loaded into the forceps during surgery, which might be cumbersome and time consuming. In addition, forceps might be large which could hinder implantation of the shape memory implant into a patient during surgery. It is also possible that a physician using the forceps might damage the shape memory implant in various ways, such as stretching the implant beyond the second shape, fatiguing the implant, or causing metal-on-metal scraping of the implant with the instrument. Furthermore, forceps can be expensive instruments that require cleaning and sterilization after each surgery.

Other companies use plastic and disposable tools to maintain a shape memory implant in the second shape. This type of instrumentation can be preloaded and sterilized with the implant already in the second shape, and the implant can be pre-activated so that it does not require heating with an external heater or body temperature after use. One type of plastic and disposable instrument operates by having the implant fit inside a passage that is substantially the same diameter as the shape memory implant. By using this method, the implant insertion device allows the shape memory implant to be preloaded prior to surgery. However, using an implant insertion device that substantially conforms to the profile of the shape memory implant can create several problems for a surgeon. First, this type of implant insertion device often makes disengagement of the shape memory staple after implantation problematic. In particular, the shape memory implant sticks to the implant insertion device due to the frictional engagement between the shape memory implant, which is trying to compress, and the passage of the implant insertion device, resulting in a more difficult surgical procedure and the potential for a less than satisfactory fixation of tissue or bone. Second, this type of implant insertion device results in an abrupt and sudden release of stored mechanical energy as the implant is removed from the device. This type of implant insertion device provides no method by which to slowly transition the stored energy in the implant from the implant insertion device to the bones that are being fixated. Finally, this type of implant insertion device can result in entanglement during release, in which the implant legs begin to compress upon release and make extraction of this type of insertion device more difficult.

Accordingly, an instrument that constrains a shape memory implant in its second shape, allows the shape memory implant to be preloaded and sterilized prior to surgery, simplifies removal of the shape memory implant after partial implantation, and controls the rate of release of tension would be beneficial.

<CIT> and <CIT> show two examples of instruments for loading and implanting an implant.

In accordance with the present disclosure, an implant insertion system includes a shape memory implant and an implant insertion device adapted for use with the shape memory implant. The shape memory implant is movable between a first shape and a second shape. In particular, the shape memory implant includes a bridge interconnecting first and second legs. The first and second legs are substantially non-parallel when the shape memory implant resides in its first shape, and the first and second legs are substantially parallel when the shape memory implant resides in its second shape. The implant insertion device maintains the shape memory implant in the second shape until the implant insertion device is used to deliver the shape memory implant into tissue or bone.

The implant insertion device includes a body having a slider receiver and a handle that allows manipulation of the implant insertion device and delivery of the shape memory implant into tissue or bone. The body includes a first arm terminating in a first jaw adapted to engage the shape memory implant and a second arm terminating in a second jaw adapted to engage the shape memory implant. The body further includes third and fourth arms terminating in a third jaw adapted to engage the shape memory implant. The first, second, and third jaws are movable from a disengaged position to an engaged position. The first arm may be shorter in length than the second arm such that the implant insertion device is adapted to receive a shape memory implant with a first bridge at a height different from a second bridge.

The implant insertion device further includes a slider coupled with the slider receiver of the body. The slider is movable between an unlocked position and a locked position. In its locked position, the slider inserts between the first jaw and the second jaw and maintains the first and second jaws in their engaged positions. The slider in its locked position further engages the third jaw and maintains the third jaw in its engaged position with the first and second jaws such that the first, second, and third jaws engage and maintain the shape memory implant in its second shape. In particular, when the first, second, and third jaws reside in their engaged positions, the first jaw engages and maintains the first leg in its substantially parallel second shape, the second jaw engages and maintains the second leg in its substantially parallel second shape, and the third jaw abuts the first and second jaws such that a portion of the third jaw inserts between the first and second jaws.

After the implant insertion device delivers the shape memory implant into tissue or bone, the slider is moved from its locked position to its unlocked position. In its unlocked position, the slider releases from the first, second, and third jaws, which permits the first, second, and third jaws to move from their engaged positions to their disengaged positions. In their disengaged positions, the first, second, and third jaws disengage from the shape memory implant, thereby releasing the shape memory implant and allowing the shape memory implant to move from its second shape to its first shape.

The first jaw experiences a rotation relative to the first arm and the second jaw experiences a rotation relative to the second arm when the slider is moved from its unlocked to its locked position. Consequently, the first jaw and the second jaw rotate away from the shape memory implant when the slider is moved from its locked to its unlocked position. In particular, the first arm maintains the first jaw canted downward and the second arm maintains the second jaw canted downward when the slider resides in its unlocked position. As such, insertion of the slider to its locked position between the first and second jaws moves the first and second jaws horizontally outward and in an upward arc to their engaged positions such that the first and second jaws engage the shape memory implant and maintain the shape memory implant in the second shape.

The first jaw includes a tooth having a leg interface that abuts the first leg of the shape memory implant when the first jaw resides in its engaged position. Likewise, the second jaw includes a tooth having a leg interface that abuts a second leg of the shape memory implant when the second jaw resides in its engaged position. The third jaw abuts the first and second jaws when the first, second, and third jaws reside in their engaged positions. Moreover, the third jaw includes a tooth that inserts between the tooth of the first jaw and the tooth of the second jaw such that the tooth of the third jaw maintains the first jaw separated from the second jaw.

The first arm and the first jaw define a first channel that engages at least a portion of the bridge of the shape memory implant when the first jaw resides in its engaged position. Similarly, the second arm and the second jaw define a second channel that engages at least a portion of the bridge of the shape memory implant when the second jaw resides in its engaged position. Furthermore, the third and fourth arms and the third jaw define a third channel that engages at least a portion of the bridge of the shape memory implant when the third jaw resides in its engaged position.

The slider includes a slot adapted to receive therein the slider receiver of the body. The slot allows coupling of the slider with the body between the first and second arms and the third and fourth arms such that the slider remains coupled with the body during movement of the slider between its unlocked and locked positions. The slider further includes a clasp securable with slider channels in each of the first, second, and third jaws. The clasp maintains the slider engaged with the first, second, and third jaws when the slider resides in its locked position.

In a method of holding a shape memory implant until the delivery of the shape memory implant into tissue or bone, a shape memory implant is provided. The shape memory implant includes a bridge interconnecting first and second legs. The shape memory implant is movable between a first shape wherein the first and second legs are non-parallel and a second shape wherein the first and second legs are substantially parallel. The shape memory implant is moved into its second shape wherein the first and second legs are substantially parallel. The shape memory implant is placed between first and second jaws of the implant insertion device and a third jaw of the implant insertion device. A slider of an implant insertion device is moved whereby the slider inserts between the first and second jaws and engages the third jaw. The slider maintains the first and second jaws in their engaged positions such that the first jaw engages the first leg of the shape memory implant and the second jaw engages the second leg of the shape memory implant. The slider further maintains the third jaw in its engaged position with the first and second jaws such that the first, second, and third jaws engage and maintain the shape memory implant in its second shape wherein the first and second legs are substantially parallel.

Once the first, second, and third jaws are engaged to maintain the shape memory implant in its second shape wherein the first and second legs are substantially parallel, the implant insertion device is used to deliver into tissue or bone the shape memory implant in its second shape. The slider of the implant insertion device is moved whereby the slider disengages from the first, second, and third jaws. As a result, the third jaw disengages with the first and second jaws. In addition, the first jaw releases the first leg of the shape memory implant and the second jaw releases the second leg of the shape memory implant, thereby releasing the shape memory implant from the implant insertion device.

Figures are not necessarily to scale, and some features may be exaggerated to show details of particular components or steps.

<FIG> illustrate a first embodiment of an implant insertion device <NUM> and an implant <NUM>. The implant insertion device <NUM> secures the implant <NUM> to allow a surgeon to insert the implant <NUM> into tissue or bone during surgery.

The implant <NUM> is a surgical staple and includes a bridge <NUM> and legs <NUM> formed integrally at corners <NUM>. The bridge <NUM> further includes a top <NUM>, a bottom <NUM>, a back <NUM>, and a front <NUM>. The legs <NUM> further include tips <NUM> which may form a shape that is rounded for insertion into drill holes or the tips <NUM> may be pointed for impaction into bones. While the preferred embodiment discloses the implant <NUM> as a surgical staple, it should be understood by one of ordinary skill in the art that any implant such as a staple or plate adapted to engage and span bone such that the implant exerts a force, typically a compressive force, to the bone is suitable for the present invention.

The implant <NUM> is composed of a shape memory material such as Nitinol that allows the implant <NUM> to have a first final shape <NUM> as illustrated in <FIG> and the ability to be elastically deformed into a second shape <NUM> as illustrated in <FIG>. The shape memory material gives the implant <NUM> elastic properties in that the implant <NUM> stores mechanical energy and is subject to elastic (recoverable) deformation when it releases the stored mechanical energy. The implant <NUM> is mechanically deformed into the second shape <NUM> and held in the second shape <NUM> by the implant insertion device <NUM> such that, upon release from the implant insertion device <NUM>, the implant <NUM> elastically transforms from the second shape <NUM> into the first final shape <NUM>.

The ability of the implant <NUM> to store mechanical energy and release that energy when it transitions from the second shape <NUM> to the first final shape <NUM> allows the implant <NUM> to fixate tissue or bone and to aid in the healing process. In particular, the implant <NUM>, which has been mechanically deformed to its second shape <NUM>, is held in implant insertion device <NUM> and inserted between tissue or bone that require fixating. After insertion, the implant <NUM> is removed from the implant insertion device <NUM>, whereupon the implant <NUM> releases the stored mechanical energy by elastically deforming to the first final shape <NUM>. This release of the stored mechanical energy by the implant <NUM> maintains the tissue or bone fixated together and aids in the healing process in that the implant <NUM> continuously applies force to the fixated tissue or bone as the implant <NUM> transitions from the second shape <NUM> to the first final shape <NUM>.

The implant insertion device <NUM> includes a body <NUM> and a slider <NUM> that moves between an unlocked and a locked position. The implant insertion device <NUM> exists in either an implant disengagement position <NUM> (shown in <FIG>) or an implant engagement position <NUM> (shown in <FIG>) and is movable therebetween. In the implant disengagement position <NUM>, the implant <NUM> slips in or out of position in the implant insertion device <NUM> with no obstruction. In the implant engagement position <NUM>, the implant insertion device <NUM> engages the implant <NUM> and maintains the implant <NUM> in the second shape <NUM>. In addition, the implant insertion device <NUM> allows a surgeon to manipulate the implant <NUM> and insert the implant <NUM> into tissue or bones that require fixating. The implant insertion device <NUM> can be made of any suitable material; however, in the first embodiment the implant insertion device <NUM> is made from plastic.

<FIG> illustrate the body <NUM> of the implant insertion device <NUM>. The body <NUM> of the implant insertion device <NUM> includes a slider receiver <NUM>, a front <NUM>, a back <NUM>, a handle <NUM> having a top <NUM>, arms <NUM> and <NUM>, and arms <NUM> and <NUM>. The slider receiver <NUM> is defined by flat grooves in the body <NUM> that receive a portion of the slider <NUM> to allow the securing of the slider <NUM> over the slider receiver <NUM> and thus to the body <NUM>. The handle <NUM> provides a gripping surface on the front <NUM> and the back <NUM> of the body <NUM>. The gripping surface of the handle <NUM> allows a surgeon to manipulate the implant insertion device <NUM> and therefore the implant <NUM> that is secured thereto. The arms <NUM> and <NUM> and the arms <NUM> and <NUM> attach to the handle <NUM> and include jaws <NUM> and a jaw <NUM>, respectively. The jaws <NUM> and the jaw <NUM> move between a disengaged position and an engaged position. Furthermore, the arms <NUM> and <NUM> and the arms <NUM> and <NUM> form slider guides <NUM> and <NUM> respectively. The slider guides <NUM> and <NUM> allow the slider <NUM> to move between its unlocked and locked position.

In the preferred embodiment, the body <NUM> of the implant insertion device <NUM> is manufactured in one piece using a mold. However, the body <NUM> of the implant insertion device <NUM> could be manufactured in two separate pieces. In particular, the arms <NUM> and <NUM>, the jaws <NUM>, and a portion of the handle <NUM> form the first piece and the arms <NUM> and <NUM>, the jaw <NUM>, and a portion of the handle <NUM> form the second piece. These two pieces are fastened together using any suitable means such as a hinge or an adhesive to create the body <NUM>.

The jaws <NUM> include teeth <NUM> that engage the implant <NUM> and the jaw <NUM> and slider channels <NUM> that engage the slider <NUM> as the slider <NUM> moves between its unlocked and its locked position. The teeth <NUM> include bridge interfaces <NUM> and leg interfaces <NUM> that engage the bridge <NUM> of the implant <NUM> as well as tooth interfaces <NUM> and jaw interfaces <NUM> that engage the jaw <NUM>. Specifically, the bridge interfaces <NUM> and a portion of the arms <NUM> and <NUM> form a bridge channel <NUM> that receives a portion of the bridge <NUM> therein. Furthermore, the leg interfaces <NUM> engage the implant <NUM> such that the leg interfaces <NUM> abut the legs <NUM> of the implant <NUM> below the corners <NUM>. The tooth interfaces <NUM> engage a portion of the jaw <NUM> that moves the jaws <NUM> from the disengaged position to the engaged position and aid in securing the implant <NUM> to the implant insertion device <NUM>.

The jaw <NUM> includes a tooth <NUM> that engages the implant <NUM> and the jaws <NUM> and a slider channel <NUM> that engages the slider <NUM> as the slider <NUM> moves between its unlocked and its locked position. The tooth <NUM> includes a bridge interface <NUM> that engages the bridge <NUM> of the implant <NUM> and tooth interfaces <NUM> and jaw interfaces <NUM> that engage the jaws <NUM>. The bridge interface <NUM> and a portion of the arms <NUM> and <NUM> form a bridge channel <NUM> that receives a portion of the bridge <NUM> therein.

The jaws <NUM> and the jaw <NUM> move between the disengaged position and the engaged position to aid in the securing and removal of the implant <NUM>. Specifically, as the implant insertion device <NUM> moves from its implant disengagement position <NUM> to its implant engagement position <NUM>, the jaws <NUM> and the jaw <NUM> move from their disengaged position to their engaged position whereby the tooth interfaces <NUM> of the jaw <NUM> engage the tooth interfaces <NUM> of the jaw <NUM>. As illustrated in <FIG>, the tooth interfaces <NUM> of the jaws <NUM> as well as the tooth interfaces <NUM> of the jaw <NUM> are beveled in order to aid in the securing and the removal of the implant <NUM> from the implant insertion device <NUM>. In the first embodiment, the beveling of the tooth interfaces <NUM> of the jaws <NUM> and the tooth interfaces <NUM> of the jaw <NUM> reduces the normal force between contacting surfaces and thus the friction force between the jaws <NUM> and the jaw <NUM> as the implant insertion device <NUM> moves between its implant disengagement position <NUM> and its implant engagement position <NUM>. The beveling of the of the tooth interfaces <NUM> of the jaws <NUM> and tooth interfaces <NUM> of the jaw <NUM> also creates a ramp that allows the jaw <NUM> to force open the jaws <NUM> similar to a wedge when the implant insertion device <NUM> moves from its disengagement position <NUM> to its implant engagement position <NUM>. One of ordinary skill in the art will recognize that the angle of the bevel and application of trigonometry determines the friction force between the tooth interfaces <NUM> of the jaws <NUM> and the tooth interfaces <NUM> of the jaw <NUM>. Reducing the amount of friction force between the tooth interfaces <NUM> of the jaws <NUM> and the tooth interfaces <NUM> of the jaw <NUM> aids in removing the implant <NUM> from the implant insertion device <NUM>. Furthermore, the angle of the bevel also determines the force for separating the jaws <NUM> when the implant insertion device <NUM> moves from its implant disengagement position <NUM> to its implant engagement position <NUM>.

<FIG> illustrates the slider <NUM>. The slider <NUM> includes a clasp <NUM> having a clasping surface <NUM> and a clasping surface <NUM> that define a slot therebetween. The slider <NUM> defines a slot <NUM> and further includes actuators <NUM> having front faces <NUM> and back faces <NUM>. The slot <NUM> allows the slider <NUM> to secure to the body <NUM> and to move between its unlocked and locked positions. In particular, placing the slider <NUM> within the slider guides <NUM> and <NUM> and engaging the slider <NUM> with the slider receiver <NUM> of the body <NUM> using the slot <NUM> secures the slider <NUM> to the body <NUM>. The actuators <NUM> allow a user to operate the slider <NUM> by moving the slider <NUM> between its unlocked and its locked position. In particular, as shown in <FIG>, when the back faces <NUM> of the actuator <NUM> are pressed, the slider <NUM> moves within the slider guides <NUM> and <NUM> from its unlocked position to its locked position. After reaching the locked position, the user may then press the front face <NUM> of the actuators <NUM>, which moves the slider <NUM> within the slider guides <NUM> and <NUM> from its locked position to its unlocked position as illustrated in <FIG>.

The clasp <NUM> of the slider <NUM> allows the slider <NUM> to lock the jaws <NUM> with the jaw <NUM>. Specifically, when the slider <NUM> moves from its unlocked position to its locked position, the clasping surfaces <NUM> and <NUM> of the clasp <NUM> engage the slider channels <NUM> of the jaws <NUM> and the slider channel <NUM> of the jaw <NUM> in a friction fit. The friction fit between the clasping surfaces <NUM> and <NUM> and the slider channels <NUM> and the slider channel <NUM>, respectively, locks the jaws <NUM> with the jaw <NUM>.

The slider <NUM>, the jaws <NUM>, and the jaw <NUM> work in concert to load the implant insertion device <NUM> with the implant <NUM>. The jaws <NUM> and the jaw <NUM> begin in their disengaged position as illustrated in <FIG> and are moved to their engaged position as illustrated <FIG>. The jaws <NUM> and the jaw <NUM> travel towards each other until the teeth <NUM> and the tooth <NUM> mate. Specifically, the tooth interfaces <NUM> of the tooth <NUM> engage the tooth interfaces <NUM> of the teeth <NUM>. Upon engagement, the tooth interfaces <NUM> of the tooth <NUM> create a wedging force on the tooth interfaces <NUM> of the teeth <NUM>. This wedging force moves the jaws <NUM> and spreads the jaws <NUM> until the jaw engagement surfaces <NUM> of the jaws <NUM> contact the jaw engagement surfaces <NUM> of the jaw <NUM> resulting in the mating of the jaws <NUM> with the jaw <NUM>.

Moving the jaws <NUM> and the jaw <NUM> from their disengaged position to their engaged position spreads the arms <NUM> and <NUM> and moves the jaws <NUM> and the arms <NUM> and <NUM> downward and horizontally outward. Likewise, the arms <NUM> and <NUM> and the jaw <NUM> move upward such that the jaw <NUM> moves the jaws <NUM> to their engaged position whereby the implant <NUM> is clamped between the jaws <NUM> and the jaw <NUM> and secured to the implant insertion device <NUM>.

In an alternative to the first embodiment of the implant insertion device <NUM>, the implant insertion device <NUM> allows easier removal of the implant <NUM> from the implant insertion device <NUM>. In particular, the jaws <NUM> can rotate when moving between the disengaged and the engaged position. Specifically, when the jaws <NUM> are in the disengaged position, the jaws <NUM> remain canted downward such that moving the jaws <NUM> to the engaged position moves the jaws <NUM> in an upward arc during clamping of the implant <NUM> by the jaws <NUM> and the jaw <NUM>. For further clarification, the jaws <NUM> exhibit a rotation relative to arms <NUM> and <NUM> when they are not engaged with the jaw <NUM>. The jaws <NUM> accordingly travel outward and upward as well as rotate relative to the arms during movement from the disengaged to the engaged position. The rotation of the jaws <NUM> relative to the arms <NUM> and <NUM> helps to insure that the jaws <NUM> more easily disengage without entanglement from the shape memory implant <NUM> during the disengagement process.

After the jaws <NUM> and the jaw <NUM> move from their disengaged position to their engaged position, the slider <NUM> moves from its unlocked to its locked position to maintain the jaws <NUM> and the jaw <NUM> in their engaged position. In moving from its unlocked to its locked position, the clasp <NUM> of the slider <NUM> engages the slider channels <NUM> of the jaws <NUM> and the slider channel <NUM> of the jaw <NUM> thereby securing the jaws <NUM> to the jaw <NUM>. Specifically, when the slider <NUM> moves from its unlocked position to its locked position, the clasping surface <NUM> engages the slider channels <NUM> of the jaws <NUM> in a friction fit and the clasping surface <NUM> engages the slider channel <NUM> of the jaw <NUM> in a friction fit. The friction fit between the clasping surfaces <NUM> and <NUM> and the slider channels <NUM> and slider channel <NUM>, respectively, locks the jaws <NUM> with the jaw <NUM>. Furthermore, the friction fit between the clasping surface <NUM> and the slider channels <NUM> maintains the implant insertion device <NUM> in its implant engagement position <NUM> and the jaws <NUM> and the jaw <NUM> in their engaged position.

To return the implant insertion device <NUM> to its implant disengagement position <NUM>, the slider <NUM> is moved from its locked position to its unlocked position. When the slider <NUM> moves to its unlocked position, the clasping surface <NUM> disengages the slider channels <NUM> of the jaws <NUM> and the clasping surface <NUM> disengages the slider channel <NUM> of the jaw <NUM> removing the friction fit. Removing the friction fit allows the jaws <NUM> to be released from the jaw <NUM> and results in movement of the arms <NUM> and <NUM> and the jaws <NUM> upward and horizontally inward. Likewise, moving the slider <NUM> from its locked position to its unlocked position allows movement of the arms <NUM> and <NUM> and the jaw <NUM> downward. The movement of the jaws <NUM> upward and horizontally inward and the jaw <NUM> downward places the jaws <NUM> and the jaw <NUM> in their disengaged position whereby the implant <NUM> may be released from the implant insertion device <NUM>.

In an alternative embodiment, the slider <NUM> when moved between its unlocked and locked positions may be configured to move the jaws <NUM> and the jaw <NUM> between their disengaged and engaged positions. In particular, the slider <NUM> may reside within tracks located within the slider guides <NUM> and <NUM>. Moving the slider <NUM> from the unlocked position to the locked position moves the slider <NUM> within the tracks located within the slider guides <NUM> and <NUM>. The slider <NUM> applies a force to the slider guide <NUM> that transfers a force to the arms <NUM> and <NUM> and moves the jaws <NUM> and the arms <NUM> and <NUM> downward and horizontally outward. Similarly, the slider <NUM> applies a force to the slider guide <NUM> that transfers a force to the arms <NUM> and <NUM> and the jaw <NUM> that moves the jaw <NUM> upward such that the jaws <NUM> and the jaw <NUM> move from their disengaged position to their engaged position whereby the implant <NUM> is clamped between the jaws <NUM> and the jaw <NUM> and secured to the implant insertion device <NUM>.

Moving the slider <NUM> from the locked position to the unlocked position moves the slider <NUM> within the tracks located within the slider guides <NUM> and <NUM>. Moving the slider <NUM> to the unlocked position releases the force that the slider guide <NUM> applies to the arms <NUM> and <NUM> and moves the jaws <NUM> and the arms <NUM> and <NUM> upward and horizontally inward. Similarly, moving the slider <NUM> to the unlocked position releases the force that the slider guide <NUM> applies to the arms <NUM> and <NUM> and moves the jaw <NUM> and the arms <NUM> and <NUM> such that the jaws <NUM> and the jaw <NUM> move from their engaged position to their disengaged position whereby the implant <NUM> is released from the implant insertion device <NUM>.

<FIG> and <FIG> illustrate the operation of securing the implant <NUM> to the implant insertion device <NUM> and the removal of the implant <NUM> from the implant insertion device <NUM>. The implant <NUM> may be preloaded on the implant insertion device <NUM> prior to surgery, or the implant <NUM> may be loaded on the implant insertion device <NUM> during surgery. The operation of loading the implant <NUM> on the implant insertion device <NUM> is as follows.

In a first method to receive the implant <NUM>, the implant insertion device <NUM> begins in its implant disengagement position <NUM> wherein the jaws <NUM> and the jaw <NUM> reside in their disengaged position. The implant <NUM> is mechanically deformed from the first final shape <NUM> into the second shape <NUM> such that the implant <NUM> stores mechanical energy. After being mechanically deformed from the first final shape <NUM> into the second shape <NUM>, the implant <NUM> is placed over the jaws <NUM> of the implant insertion device <NUM> such that a portion of the bridge <NUM> resides with the bridge channel <NUM>. Specifically, the bottom <NUM> of the bridge <NUM> resides adjacent the bridge interfaces <NUM> and the top <NUM> of the bridge <NUM> resides adjacent the arms <NUM> and <NUM> of the body <NUM>.

After the implant <NUM> is placed over the jaws <NUM>, the jaws <NUM> and the jaw <NUM> are moved from their disengaged position to their engaged position. In moving from the disengaged position to the engaged position, the jaws <NUM> move downward and the jaw <NUM> moves upward. In addition, the tooth interfaces <NUM> of the tooth <NUM> engage the tooth interfaces <NUM> of the teeth <NUM>. Upon engagement, the tooth interfaces <NUM> of the tooth <NUM> create a wedging force on the tooth interfaces <NUM> of the teeth <NUM> that continues until the jaw engagement surfaces <NUM> of the jaws <NUM> contact the jaw engagement surfaces <NUM> of the jaw <NUM>. This wedging force spreads the arms <NUM> and <NUM> and the jaws <NUM> and moves the arms <NUM> and <NUM> and the jaws <NUM> downward and horizontally outward until the leg interfaces <NUM> engage the implant <NUM>. Specifically, the leg interfaces <NUM> engage the implant <NUM> such that the leg interfaces <NUM> abut the legs <NUM> of the implant <NUM> below the corners <NUM>. Furthermore, moving the jaws <NUM> and jaw <NUM> from the disengaged position to the engaged position inserts the bridge <NUM> of the implant <NUM> within the bridge channel <NUM> of the jaw <NUM>. Specifically, the bottom <NUM> of the bridge <NUM> resides adjacent the bridge interface <NUM> and the tops <NUM> of the bridge <NUM> resides adjacent the arms <NUM> and <NUM> of the body <NUM> thereby clamping implant <NUM> between the jaws <NUM> and the jaw <NUM>. Clamping the implant <NUM> between the jaws <NUM> and the jaw <NUM> maintains the mechanical energy stored in the implant <NUM> and tensions the implant plant <NUM> against the jaws <NUM>. In addition, the implant <NUM> remains loaded on the implant insertion device <NUM> while jaws <NUM> maintain the implant <NUM> in the second shape <NUM>.

After the jaws <NUM> and the jaw <NUM> move from the disengaged to the engaged position, the slider <NUM> is moved from its unlocked to its locked position. In particular, the back faces <NUM> of the actuators <NUM> are pressed moving the slider <NUM> within the slider guides <NUM> and <NUM> such that the clasping surfaces <NUM> and <NUM> of the clasp <NUM> engage the slider channels <NUM> and the slider channel <NUM>, respectively, locking the jaws <NUM> with the jaw <NUM>.

While the implant <NUM> may be mechanically deformed from the first final shape <NUM> into its second shape <NUM> before placement on the implant insertion device <NUM>, in a second method, the implant <NUM> also may be placed on the implant insertion device <NUM> in the first final shape <NUM> and then mechanically deformed to the second shape <NUM> by the implant insertion device <NUM>. The jaws <NUM> and the jaw <NUM> are moved from their disengaged position to their engaged position using any suitable means such as for example a mechanical press. As described above, moving the jaws <NUM> and the jaw <NUM> from their disengage position to their engaged position causes a wedging force that spreads the arms <NUM> and <NUM> and the jaws <NUM> and moves the arms <NUM> and <NUM> and the jaws <NUM> downward and horizontally outward such that the leg interfaces <NUM> engage the implant <NUM>. This wedging force transfers to the implant <NUM> such that the implant <NUM> moves from its first final shape <NUM> to its second shape <NUM>. This force transfer imparts mechanical energy into the implant <NUM> and tensions the implant <NUM> against the jaws <NUM>. Furthermore, the slider <NUM> moves from its unlocked to its locked position to maintain the jaws <NUM> and the jaw <NUM> in the engaged position such that the implant <NUM> remains loaded on the implant insertion device <NUM> while the implant insertion device <NUM> also maintains the implant <NUM> in the second shape <NUM>. Although not necessary, the implant <NUM> may be cooled prior to placement on the implant insertion device <NUM> in order to place it in a martensitic state and aid in movement of the implant <NUM> from its first final shape <NUM> to the second shape <NUM>.

After the implant <NUM> is secured to the implant insertion device <NUM>, the implant <NUM> is ready to be implanted into tissue or bones. The surgeon places the tips <NUM> of the implant <NUM> into predrilled holes or the tips may be impacted into the tissue or bones thereby securing the implant <NUM> into the tissue or bones. Once the implant <NUM> is secured to the tissue or bones, it is ready for removal from the implant insertion device <NUM>. To remove the implant <NUM> from the implant insertion device <NUM>, the surgeon presses the front face <NUM> of the actuators <NUM>, which moves the slider <NUM> within the slider guides <NUM> and <NUM> from its locked position to its unlocked position. Moving the slider <NUM> from its locked position to its unlocked position, disengages the clasping surfaces <NUM> and <NUM> from the slider channel <NUM> and the slider channel <NUM> respectively, thereby allowing the jaws <NUM> and the jaw <NUM> to move to the disengaged position.

Moving from the engaged position to the disengaged position allows the jaws <NUM> to be released from the jaw <NUM> allowing upward movement of the jaws <NUM> and downward movement of the jaw <NUM>. Furthermore, the arms <NUM> and <NUM> and the jaws <NUM> move upward and horizontally inward and the arms <NUM> and <NUM> and the jaw <NUM> move downward such that the implant <NUM> may be released from the implant insertion device <NUM>. When the jaws <NUM> and the jaw <NUM> are in their disengaged position, the leg interfaces <NUM> of the jaws <NUM> no longer abut the legs <NUM> of the implant <NUM>, resulting in the release of the tension between the implant <NUM> and the jaws <NUM> and a release of the implant <NUM> from the implant insertion device <NUM>.

In the event the implant <NUM> remains engaged with the jaws <NUM> after the jaws <NUM> and the jaw <NUM> have moved from their engaged position to the disengaged position, the implant <NUM> may be removed from the implant insertion device <NUM> by applying a twisting force. In particular, if the implant <NUM> remains engaged with either the bridge channel <NUM> of the jaws <NUM> or the bridge channel <NUM> of the jaw <NUM>, applying a twisting force to the implant insertion device <NUM> removes the implant <NUM> therefrom. The twisting or rotational force overcomes the force the bridge channel <NUM> or the bridge channel <NUM> applies against the implant <NUM>. As a result, the bridge channel <NUM> or the bridge channel <NUM> separates from the implant <NUM>, thereby releasing the implant <NUM> from the implant insertion device <NUM>.

After the implant <NUM> is removed from the implant insertion device <NUM>, the implant <NUM> is tamped down to fully engage the tissue or bone. Once fully engaged, the implant <NUM> moves from its second shape <NUM> to its first final shape <NUM>, thereby releasing its mechanical energy into the tissue or bone. As the implant <NUM> moves from its second shape <NUM> to its first final shape <NUM>, the implant <NUM> places a constant force on the tissue or bones that fuses the tissue or bone together and aids the healing process.

The design of the implant insertion device <NUM> allows a gradual release of the implant <NUM>. In particular, if the surgeon presses actuators <NUM> quickly, then the slider <NUM> moves from its locked to its unlocked position quickly and the jaws <NUM> and the jaw <NUM> move from their engaged position to their disengaged position quickly thereby rapidly releasing the implant <NUM>. On the other hand, if the surgeon believes a patient has poor bone quality, the surgeon can slowly press the actuators <NUM>, which slowly moves the slider <NUM> from the locked to the unlocked position. Slowly moving the slider <NUM> from the locked to the unlocked position allows the jaws <NUM> and the jaw <NUM> to slowly move from their engaged position to their disengaged position thereby gradually releasing the implant <NUM>.

<FIG> illustrate a second embodiment of an implant insertion device <NUM> and an implant <NUM>. The implant <NUM> is secured to the implant insertion device <NUM> allowing a surgeon to insert the implant <NUM> into tissue or bone during surgery.

In the second embodiment, the implant <NUM> is a surgical staple and includes two bridges <NUM> and <NUM> and legs <NUM> formed integrally at corners <NUM>. The bridges <NUM> and <NUM> each include a top <NUM>, a bottom <NUM>, a back <NUM>, and a front <NUM>. The legs <NUM> further include tips <NUM> which may form a shape that is rounded for insertion into drill holes or the tips <NUM> may be pointed for impaction into bones. While the second embodiment discloses the implant <NUM> as a surgical staple, it should be understood by one of ordinary skill in the art that any implant adapted to engage and span bone such that the implant exerts a force, typically a compressive force, to the bone is suitable for the present invention.

The implant <NUM> is composed of a shape memory material such as Nitinol that allows the implant <NUM> to have a first shape <NUM> as illustrated in <FIG> and the ability to transform into a second shape <NUM> as illustrated in <FIG>. The shape memory material gives the implant <NUM> elastic properties in that the implant <NUM> stores mechanical energy and is subject to elastic (recoverable) deformation when it releases the stored mechanical energy. The implant <NUM> is mechanically deformed into the second shape <NUM> and held in the second shape <NUM> by the implant insertion device <NUM> such that, upon release from the implant insertion device <NUM>, the implant <NUM> elastically deforms from the second shape <NUM> into the first shape <NUM>.

<FIG> illustrate the body <NUM> of the implant insertion device <NUM>. The body <NUM> of the implant insertion device <NUM> includes a slider receiver <NUM>, a front <NUM>, a back <NUM>, a handle <NUM> having a top <NUM>, arms <NUM> and <NUM>, and arms <NUM> and <NUM>. The slider receiver <NUM> is defined by flat grooves in the body <NUM> that receive a portion of the slider <NUM> to allow the securing of the slider <NUM> over the slider receiver <NUM> and thus to the body <NUM>. The handle <NUM> provides a gripping surface on the front <NUM> and the back <NUM> of the body <NUM>. The gripping surface of the handle <NUM> allows a surgeon to manipulate the implant insertion device <NUM> and therefore the implant <NUM> that is secured thereto. The arms <NUM> and <NUM> and the arms <NUM> and <NUM> attach to the handle <NUM> and include jaws <NUM> and a jaw <NUM>, respectively. The jaws <NUM> and the jaw <NUM> move between a disengaged position and an engaged position. Furthermore, the arms <NUM> and <NUM> and the arms <NUM> and <NUM> form slider guides <NUM> and <NUM> respectively. The slider guides <NUM> and <NUM> allow the slider <NUM> to move between its unlocked and locked position. As shown in <FIG>, the arms <NUM> and <NUM> are shorter in length than the arms <NUM> and <NUM> to accommodate the difference in bridge height of the staple implant <NUM>. The arms <NUM> and <NUM> and the arms <NUM> and <NUM> are designed to be flexible if an external force is applied thereto. One of ordinary skill in the art will recognize that the arms <NUM> and <NUM> and the arms <NUM> and <NUM> can be at many relative angles from each other. One skilled in the art will further recognize that the length and height difference of the arms <NUM> and <NUM> and the arms <NUM> and <NUM> may vary to deliver a variety of results.

The jaws <NUM> include teeth <NUM> that engage the implant <NUM> and the jaw <NUM> and slider channels <NUM> that engage the slider <NUM> as the slider <NUM> moves between its unlocked and its locked position. The teeth <NUM> include bridge interfaces <NUM> and leg interfaces <NUM> that engage the bridges <NUM> and <NUM> of the implant <NUM> as well as tooth interfaces <NUM> and jaw interfaces <NUM> that engage the jaw <NUM>. Specifically, the bridge interfaces <NUM> and a portion of the arms <NUM> and <NUM> form a bridge channel <NUM> that receives a portion of the bridges <NUM> and <NUM> therein. Furthermore, the leg interfaces <NUM> engage the implant <NUM> such that the leg interfaces <NUM> abut the legs <NUM> of the implant <NUM> below the corners <NUM>. The tooth interfaces <NUM> engage a portion of the jaw <NUM> that moves the jaws <NUM> from the disengaged position to the engaged position and aid in securing the implant <NUM> to the implant insertion device <NUM>.

The jaw <NUM> includes a tooth <NUM> that engages the implant <NUM> and the jaws <NUM> and a slider channel <NUM> that engages the slider <NUM> as the slider <NUM> moves between its unlocked and its locked position. The tooth <NUM> includes a bridge interface <NUM> that engages the bridges <NUM> and <NUM> of the implant <NUM> and tooth interfaces <NUM> and jaw interfaces <NUM> that engage the jaws <NUM>. The bridge interface <NUM> and a portion of the arms <NUM> and <NUM> form a bridge channel <NUM> that receives a portion of the bridges <NUM> and <NUM> therein.

<FIG> illustrates the slider <NUM>. The slider <NUM> includes a clasp <NUM> having a clasping surface <NUM> and a clasping surface <NUM> that define a slot therebetween. The clasp <NUM> includes notches <NUM> and <NUM> to accommodate the difference in lengths between the arms <NUM> and <NUM> and the arms <NUM> and <NUM>. The slider <NUM> defines a slot <NUM> and further includes actuators <NUM> having front faces <NUM> and back faces <NUM>. The slot <NUM> allows the slider <NUM> to secure to the body <NUM> and to move between its unlocked and its locked position. In particular, placing the slider <NUM> within the slider guides <NUM> and <NUM> and engaging the slider <NUM> with the slider receiver <NUM> of the body <NUM> using the slot <NUM> secures the slider <NUM> to the body <NUM>. The actuators <NUM> allow a user to operate the slider <NUM> by moving the slider <NUM> between its unlocked and its locked position. In particular, as shown in <FIG>, when the back faces <NUM> of the actuator <NUM> are pressed, the slider <NUM> moves within the slider guides <NUM> and <NUM> from its unlocked position to its locked position. After reaching the locked position, the user may then press the front face <NUM> of the actuators <NUM>, which moves the slider <NUM> within the slider guides <NUM> and <NUM> from its locked position to its unlocked position as illustrated in <FIG>.

In an alternative to the second embodiment of the implant insertion device <NUM>, the implant insertion device <NUM> allows easier removal of the implant <NUM> from the implant insertion device <NUM>. In particular, the jaws <NUM> can rotate when moving between the disengaged position and the engaged position. Specifically, when the jaws <NUM> are in the disengaged position, the jaws <NUM> remain canted downward such that moving the jaws <NUM> to the engaged position moves the jaws <NUM> in an upward arc during clamping of the implant <NUM> by the jaws <NUM> and the jaw <NUM>. For further clarification, the jaws <NUM> exhibit a rotation relative to arms <NUM> and <NUM> when they are not engaged with the jaw <NUM>. The jaws <NUM> accordingly travel outward and upward as well as rotate relative to the arms during movement from the disengaged position to the engaged position. The rotation of the jaws <NUM> relative to the arms <NUM> and <NUM> helps to insure that the jaws <NUM> more easily disengage without entanglement from the shape memory implant <NUM> during the disengagement process.

In a first method to receive the implant <NUM>, the implant insertion device <NUM> begins in its implant disengagement position <NUM> wherein the jaws <NUM> and the jaw <NUM> reside in their disengaged position. The implant <NUM> is mechanically deformed from the first final shape <NUM> into the second shape <NUM> such that the implant <NUM> stores mechanical energy. After being mechanically deformed from the first final shape <NUM> into the second shape <NUM>, the implant <NUM> is placed over the jaws <NUM> of the implant insertion device <NUM> such that a portion of the bridges <NUM> and <NUM> reside with the bridge channel <NUM>. Specifically, the bottoms <NUM> of the bridges <NUM> and <NUM> reside adjacent the bridge interfaces <NUM> and the tops <NUM> of the bridges <NUM> and <NUM> reside adjacent the arms <NUM> and <NUM> of the body <NUM>.

After the implant <NUM> is placed over the jaws <NUM>, the jaws <NUM> and the jaw <NUM> are moved from their disengaged position to their engaged position. In moving from the disengaged position to the engaged position, the jaws <NUM> move downward and the jaw <NUM> moves upward. In addition, the tooth interfaces <NUM> of the tooth <NUM> engage the tooth interfaces <NUM> of the teeth <NUM>. Upon engagement, the tooth interfaces <NUM> of the tooth <NUM> create a wedging force on the tooth interfaces <NUM> of the teeth <NUM> that continues until the jaw engagement surfaces <NUM> of the jaws <NUM> contact the jaw engagement surfaces <NUM> of the jaw <NUM>. This wedging force spreads the arms <NUM> and <NUM> and the jaws <NUM> and moves the arms <NUM> and <NUM> and the jaws <NUM> downward and horizontally outward until the leg interfaces <NUM> engage the implant <NUM>. Specifically, the leg interfaces <NUM> engage the implant <NUM> such that the leg interfaces <NUM> abut the legs <NUM> of the implant <NUM> below the corners <NUM>. Furthermore, moving the jaws <NUM> and jaw <NUM> from the disengaged position to the engaged position inserts the bridges <NUM> and <NUM> of the implant <NUM> within the bridge channel <NUM> of the jaw <NUM>. Specifically, the bottoms <NUM> of the bridges <NUM> and <NUM> reside adjacent the bridge interface <NUM> and the tops <NUM> of the bridges <NUM> and <NUM> reside adjacent the arms <NUM> and <NUM> of the body <NUM> thereby clamping implant <NUM> between the jaws <NUM> and the jaw <NUM>. Clamping the implant <NUM> between the jaws <NUM> and the jaw <NUM> maintains the mechanical energy stored in the implant <NUM> and tensions the implant plant <NUM> against the jaws <NUM>. In addition, the implant <NUM> remains loaded on the implant insertion device <NUM> while jaws <NUM> maintain the implant <NUM> in the second shape <NUM>.

While the implant <NUM> may be mechanically deformed from the first final shape <NUM> into its second shape <NUM> before placement on the implant insertion device <NUM>, in a second method, the implant <NUM> also may be placed on the implant insertion device <NUM> in the first final shape <NUM> and then mechanically deformed to the second shape <NUM> by the implant insertion device <NUM>. The jaws <NUM> and the jaw <NUM> are moved from their disengaged position to their engaged position using any suitable means such as for example a mechanical press. As described above, moving the jaws <NUM> and the jaw <NUM> from their disengage position to their engaged position causes a wedging force that spreads the arms <NUM> and <NUM> and the jaws <NUM> and moves the arms <NUM> and <NUM> and the jaws <NUM> downward and horizontally outward such that the leg interfaces <NUM> engage the implant <NUM>. This wedging force transfers to the implant <NUM> such that the implant <NUM> moves from its first final shape <NUM> to its second shape <NUM>. This force transfer imparts mechanical energy into the implant <NUM> and tensions the implant <NUM> against the jaws <NUM>. Furthermore, the slider <NUM> moves from its unlocked to its locked position to maintain the jaws <NUM> and the jaw <NUM> in the engaged position such that the implant <NUM> remains loaded on the implant insertion device <NUM> while the implant insertion device <NUM> also maintains the implant <NUM> in the second shape <NUM>. Although not necessary, the implant <NUM> may be cooled prior to placement on the implant insertion device <NUM> in order to place it in a martensitic state and aid in movement of the implant <NUM> from its first final shape <NUM> to the second shape <NUM>.

Claim 1:
An implant insertion device (<NUM>) adapted for use with a shape memory implant (<NUM>) movable between a first shape and a second shape, whereby the implant insertion device maintains the shape memory implant in the second shape until the delivery of the shape memory implant into tissue or bone, the implant insertion device comprising:
(i) a body (<NUM>), comprising:
a first jaw (<NUM>) adapted to engage the shape memory implant,
a second jaw (<NUM>) adapted to engage the shape memory implant, and
a third jaw (<NUM>) adapted to engage the shape memory implant, wherein the first, second, and third jaws (<NUM>, <NUM>) are movable from a disengaged position to an engaged position; and
(ii) a slider (<NUM>) coupled with the body (<NUM>), wherein the slider (<NUM>) is movable between an unlocked position and a locked position, further wherein the slider (<NUM>) in its locked position is capable of maintaining the first, second, and third jaws (<NUM>, <NUM>) in their engaged positions,
wherein the body (<NUM>) further comprises:
a first arm (<NUM>), wherein the first jaw (<NUM>) is at the termination of the first arm (<NUM>);
a second arm (<NUM>), wherein the second jaw (<NUM>) is at the termination of a second arm (<NUM>); and
a third arm (<NUM>) and a fourth arm (<NUM>), wherein the third jaw (<NUM>) is at the termination of the third and fourth arms (<NUM>, <NUM>)
wherein the slider (<NUM>) in its locked position is capable of inserting between the first jaw (<NUM>) and the second jaw (<NUM>) and is capable of maintaining the first and second jaws (<NUM>) in their engaged positions, further wherein the slider (<NUM>) in its locked position is capable of engaging the third jaw (<NUM>) and is capable of maintaining the third jaw (<NUM>) in its engaged position with the first and second jaws (<NUM>) such that the first, second, and third jaws (<NUM>, <NUM>) are capable of engaging and maintaining the shape memory implant in its second shape, and
characterized in that
the first arm (<NUM>) is shorter in length than the second arm (<NUM>) such that the implant insertion device (<NUM>) is adapted to receive a shape memory implant (<NUM>) with a first bridge (<NUM>, <NUM>) at a height different from a second bridge (<NUM>, <NUM>).