Patent Description:
Bone plate systems are known for stabilizing bones. As used herein, the term "bone" refers to a whole bone or a portion of a bone. The bones stabilized by a bone plate system may be, for example, portions of a single bone such as a broken clavicle bone or separate vertebrae. One application of bone plate systems is to secure two or more vertebrae together with an intervertebral implant between the vertebrae. Another application of bone plate systems is to fuse portions of a bone that have been separated by a break or a cut. For example, a bone plate system may be used to facilitate fusion of portions of a broken bone of a clavicle, scapula, foot, or other extremity.

<CIT> describes a retaining mechanism for use in affixing a stratum to bone. The mechanism comprises a stratum comprising a first surface, a second surface, and a hole extending between the two surfaces. The hole has a central longitudinal axis extending substantially perpendicular to the two surfaces. The retaining element comprises a first position that permits a fastener to be passed through the hole, a second position that at least partially overlaps the hole, and a spring element. The spring element is configured to engage the stratum, configured to move in a direction substantially perpendicular to the central longitudinal axis of the hole when the retaining element moves between its first and second positions, and configured to engage the retaining element to help maintain the retaining element in its second position to help prevent inadvertent backing out of the fastener after it has been fully inserted into the hole.

<CIT> describes a bone fracture plate assembly including female and male plate portions. The female plate portion has a post, a female dovetail, and an extending arm with a group of ratchet teeth. The male plate portion has two upstanding posts, a male dovetail for coupling to the female dovetail so that the plate portions move linearly with respect to each other, a slot for the arm, and a pawl for engaging the ratchet teeth. A spring, coupled to the posts of the plate portions, dynamically connects the plate portions by applying a compressive load therebetween. The spring has a pair of elongated ears, each defining a slot to allow for relative movement of the plate portions. The ratchet teeth are engaged by the pawl to retain the plate portions together, and the spring mounts on the posts of the plate portions such that the spring biases the plate portions together.

These methods do not form part of the invention. In accordance with the present invention, a bone plate system is provided that includes a bone plate having a plurality of elongated through openings. Each elongated through opening has a pair of end portions across the through opening from each other. The bone plate system includes a plurality of bone screws each having a head portion and a shank portion, the shank portion being configured to be driven into a bone. The bone plate system includes a plurality of sliders in the elongated through openings of the bone plate. Each slider has a throughbore configured to receive the head portion of one of the bone screws. The sliders and bone screw head portions received therein are shiftable within the elongated through openings relative to the bone plate. The bone plate system includes at least one resilient member for being configured to apply a biasing force to each of the sliders to urge the slider toward one end portion of a respective through opening. Further, the bone plate system includes at least one actuator having an interference position in which the actuator inhibits shifting of the sliders toward the one end portion of the respective through opening. The at least one actuator also has a clearance position in which the actuator permits the at least one resilient member to urge the sliders and the bone screws received therein toward the one end portion of the through openings. In this manner, the bone plate system may be secured to bones and the at least one actuator moved from the interference position to the clearance position to cause the at least one resilient member to urge the sliders and bone screws along the elongated through openings and compress the bones together. Further, the bone plate is made of a rigid material such as titanium to resist post-surgical loading from the bones and keep the bones compressed together.

An embodiment of the present invention provides a bone plate system for securing a pair of bones. The bone plate system includes a bone plate, elongated through openings of the bone plate, and a pair of bone screws for securing the bone plate to the bones. The bone plate system further includes a pair of sliders in the elongated through openings that each have a through bore for receiving a bone screw and at least one actuator configured to be clamped between the sliders and the bone plate. Further, the bone plate system includes at least one resilient member configured for applying a biasing force to the sliders to urge the sliders against the at least one actuator and cause the sliders to clamp the at least one actuator between the sliders and the bone plate. The at least one actuator is removable from being clamped between the sliders and the bone plate so that the biasing force urges each slider and the bone screw therein toward the other slider and bone screw for compressing the bones together. The bone plate system thereby provides a secure assembly of the at least one actuator clamped between the sliders and the bone plate which improves the ease of handling of the bone plate system during installation. Further, the at least one resilient member provides an easy-to-use approach for applying a biasing force against the bones by removing the at least one actuator from the bone plate.

The bone plate system of the present invention can be usefully applied in a method for compressing a pair of bones as described herein (not part of the claimed invention). The method includes positioning a bone plate against bones and driving shanks of bone screws into through bores of sliders in elongated through openings of the bone plate and into engagement with the bones. The method includes removing at least one actuator from the bone plate and permitting at least one resilient member to urge the sliders and bone screw head portions therein toward each other along the elongated through openings of the bone plate and compress the bones together. In this manner, the method can be utilized to quickly secure the bone plate to the bones by driving the bone screws into through bores of the sliders and compress the bones by removing the at least one actuator from the bone plate.

With reference to <FIG>, a bone plate system <NUM> is provided that includes a bone plate <NUM> having one or more through openings <NUM> therein that receive one or more slider assemblies <NUM>. The slider assemblies <NUM> each include a slider <NUM> and one or more resilient members such as wires <NUM>, <NUM> (see <FIG>). The wires <NUM>, <NUM> have a loaded configuration wherein the wires <NUM>, <NUM> apply a biasing force to the sliders <NUM> which urges each of the sliders <NUM> toward one end portion <NUM> (see <FIG>) of the respective through opening <NUM>. The bone plate system <NUM> also includes at least one actuator, such as spacers <NUM>, which resist movement of the sliders <NUM> toward the one end portion <NUM> of the respective through opening <NUM> and keep the wires <NUM>, <NUM> in a loaded configuration. Because the spacers <NUM> keep the wires <NUM>, <NUM> in the loaded configuration, the wires <NUM>, <NUM> have a preload that may be released by removing the spacers <NUM> from the through openings <NUM>. The sliders <NUM> include sliders 18A, 18B for being secured to a first bone <NUM> (see <FIG>) and sliders 18C, 18D for being secured to a second bone <NUM>. The sliders <NUM> each include one or more through bores <NUM> that receive bone anchors such as bone screws <NUM>.

To install the bone plate system <NUM>, the bone plate <NUM> is positioned against the bones <NUM>, <NUM> and the bone screws <NUM> are driven into the through bores <NUM> of the sliders <NUM> and into the bones <NUM>, <NUM> until head portions <NUM> of the bone screws <NUM> are seated in the through bores <NUM> of the sliders <NUM> as shown in <FIG>. Next, a user operates the at least one actuator to cause the bone plate system <NUM> to compress the bones <NUM>, <NUM>. In one embodiment, the user operates the at least one actuator by removing the spacers <NUM> from the bone plate <NUM> generally in direction <NUM>. Once the spacers <NUM> have been removed, the wires <NUM>, <NUM> of the slider assemblies <NUM> can unload and urge the sliders 18A, 18B and bone screws <NUM> therein in direction <NUM> and urge the sliders 18C, 18D and bone screws <NUM> therein in direction <NUM>. This compresses the bones <NUM>, <NUM> together as shown in <FIG>. Compressing the bones <NUM>, <NUM> encourages fusion of the bones <NUM>, <NUM> together or, in another embodiment, fusion of the bones <NUM>, <NUM> together with a device therebetween such as an intervertebral implant between two vertebrae.

With reference to <FIG>, the spacers <NUM> each include a head <NUM> and a body <NUM>. The head <NUM> is configured to be engaged by an actuator removal instrument such as spacer removal instrument <NUM> (see <FIG>). With reference to the slider 18D, the body <NUM> of the spacer <NUM> is sized to extend into one of the through openings <NUM> and separate the slider 18D from a laterally extending wall <NUM> of the bone plate <NUM>. More specifically, the body <NUM> includes flats <NUM>, <NUM> with the flat <NUM> engaging a flat surface <NUM> of the slider 18D and the flat <NUM> engaging a flat surface <NUM> of the wall <NUM>. With the spacer <NUM> connected to the bone plate <NUM>, the presence of the spacer body <NUM> in the through opening <NUM> keeps the slider 18D at one end portion <NUM> of the through bore <NUM> and maintains the wires <NUM>, <NUM> in a loaded configuration (see <FIG>). The biasing force provided by the wires <NUM>, <NUM> clamps the body <NUM> of the spacer <NUM> between the slider 18D and the wall <NUM> of the bone plate <NUM>. By removing the spacers <NUM> from the bone plate <NUM>, the wires <NUM>, <NUM> can shift slider 18D in direction <NUM> toward an opposite end portion <NUM> of the through opening <NUM>. The sliders 18A, 18B, 18C operate in a similar manner as discussed with respect to slider 18D.

The bone plate <NUM>, sliders <NUM>, and spacers <NUM> are made of rigid materials meaning that they are not intended to deform during normal installation and post-surgical use of the bone plate system <NUM>. In one example, the bone plate <NUM>, sliders <NUM>, and spacers <NUM> are made of a metallic material such as titanium. The rigidity of the spacers <NUM> keeps the wires <NUM>, <NUM> from being able to shift to the unloaded configuration thereof while the spacers <NUM> are present in the through openings <NUM>.

The wires <NUM>, <NUM> are made of a resilient material meaning that the wires <NUM>, <NUM> are deformable and are able to recoil or spring back to shape after bending. Other resilient members may be used such as resilient members that recoil or spring back to shape after being stretched or compressed. The wires <NUM>, <NUM> together apply a predetermined biasing force to the respective slider <NUM> such as in the range of approximately five pounds to approximately fifteen pounds, such as approximately ten pounds of force. The wires <NUM>, <NUM> of the sliders <NUM> are also additive with the other levels of the bone plate <NUM> so that, with four sliders <NUM>, the sliders <NUM> and bone screws <NUM> therein compress the bones <NUM>, <NUM> with a compressive force of forty pounds.

In one example, the wires <NUM>, <NUM> are made of a superelastic material. The superelastic material may be a metallic material such as superelastic nitinol. As an example, the wires <NUM>, <NUM> may be made of superelastic nitinol and may each have a diameter of <NUM> inches. The bone plate system <NUM> utilizing these wires <NUM>, <NUM> may provide <NUM> lbs of compressive force. The biasing force of the wires <NUM>, <NUM> increases rapidly with relatively small increases in diameter. For example, the bone plate system <NUM> utilizing superelastic nitinol wires <NUM>, <NUM> each having a diameter of <NUM> inches may provide <NUM> lbs of compressive force.

As used herein, the terms loaded configuration and unloaded configuration with reference to wires <NUM>, <NUM> are relative terms wherein the wires <NUM>, <NUM> are loaded or deformed more in the loaded configuration than in the unloaded configuration. Thus, when the wires <NUM>, <NUM> are described as being in the unloaded configuration, it is not intended that the wires <NUM>, <NUM> must be completely unloaded, just that the wires <NUM>, <NUM> are less loaded or deformed than when the wires are in the loaded configuration.

Regarding <FIG>, the spacer <NUM> is configured to facilitate removal of the spacer <NUM> by the spacer removal instrument <NUM>. In one form, the spacer <NUM> includes a shoulder <NUM> that seats on an upper surface <NUM> of the bone plate <NUM>. The shoulder <NUM> positions an underside surface <NUM> of the head <NUM> at distance <NUM> above the bone plate upper surface <NUM>. The distance <NUM> creates a gap <NUM> of the bone plate <NUM>/spacer <NUM> assembly into which a portion of the instrument <NUM> may fit and engage the underside surface <NUM> of the head <NUM>. The bone plate <NUM> has a lower surface <NUM> opposite the upper surface <NUM> for being positioned against the bones <NUM>, <NUM>. The lower surface <NUM> may have a concave curvature to compliment the external surfaces of the bones <NUM>, <NUM>.

With reference to <FIG>, the bone plate <NUM> has been positioned against the bones <NUM>, <NUM> which are separated by a small gap <NUM>. The bone screws <NUM> have been driven into the through bores <NUM> of the sliders <NUM>. In the embodiment of <FIG>, the bone plate <NUM> has a longitudinal axis <NUM> and all of the sliders 18A, 18B, 18C, 18D are aligned along the longitudinal axis. This provides a small footprint for the bone plate <NUM> on the bones <NUM>, <NUM> and is well suited for narrow bones such as bones of the clavicle, foot, or other extremities.

With reference to <FIG>, the spacers <NUM> are connected to bone plate <NUM> and hold the sliders <NUM> at the end portion <NUM> of the through openings <NUM>. Because the sliders <NUM> are held at the end portion <NUM> of the through openings <NUM>, the sliders <NUM> maintain the wires <NUM>, <NUM> in the loaded configuration. The wires <NUM>, <NUM> extend through passageways <NUM>, <NUM> (see <FIG>) of the sliders <NUM> and have a bent configuration around walls <NUM>, <NUM> of the sliders <NUM>. The wires <NUM>, <NUM> each have an intermediate portion <NUM> secured to the slider <NUM>. In one embodiment, the intermediate portion <NUM> is secured to the slider <NUM> such as by forming a dimple in an upper surface <NUM> (see <FIG>) of an upper wall <NUM> of the slider <NUM> which deforms the upper wall <NUM> into engagement with the intermediate portion <NUM>.

Regarding <FIG>, the wires <NUM>, <NUM> include end portions <NUM>, <NUM> extending out of the passageways <NUM>, <NUM> and are received in wire-receiving portions <NUM>, <NUM> of the bone plate <NUM>. The wire-receiving portions <NUM>, <NUM> include pairs of apertures <NUM>, <NUM> that receive wire end portions <NUM>, <NUM>. More specifically, the end portions <NUM>, <NUM> of the wire <NUM> extend out of the passageway <NUM> and into apertures <NUM>, <NUM> of the bone plate <NUM>. Likewise, the end portions <NUM>, <NUM> of the wire <NUM> extend out of the passageway <NUM> and into apertures <NUM>, <NUM> of the bone plate <NUM>. The wires <NUM>, <NUM> support the sliders <NUM> in the through openings <NUM>. The wires <NUM>, <NUM> are made of a material and have a diameter sufficient to provide pull-through resistance for the sliders <NUM> such that the sliders <NUM> and bone screws <NUM> therein stay within the through openings <NUM> of the bone plate <NUM> despite loads applied to the bone screws <NUM> by the bones <NUM>, <NUM>.

With reference to <FIG>, the spacers <NUM> have been removed from the bone plate <NUM> which permits the wires <NUM>, <NUM> to unload by straightening. The unloading wires <NUM>, <NUM> convert the preload or stored potential energy within the wires <NUM>, <NUM> into biasing forces which shift the sliders 18A, 18B in direction <NUM> and sliders 18C, 18D in direction <NUM>. The shifting of the sliders <NUM> in directions <NUM>, <NUM> urges the bones <NUM>, <NUM> together and removes the gap <NUM> therebetween. In one embodiment, the wires <NUM>, <NUM> are able to shift the sliders <NUM> from the end portions <NUM> of the through openings <NUM> to the opposite end portions <NUM> of the through openings <NUM>. Further, depending on patient anatomy, the wires <NUM>, <NUM> may urge the sliders <NUM> less than the entire distance along the through openings <NUM>. If the sliders <NUM> are spaced from the laterally extending walls of the bone plate <NUM> at the end portion <NUM> of the through opening <NUM>, the wires <NUM>, <NUM> will be bent and will continue to apply a biasing force to the sliders <NUM>.

With reference to <FIG>, the wires <NUM>, <NUM> are shown in an unloaded configuration after the spacers <NUM> have been removed and the wires <NUM>, <NUM> have urged the sliders <NUM> to the end portions <NUM> of the through openings <NUM>. In the unloaded configuration, the wires <NUM>, <NUM> are substantially straight with the end portions <NUM>, <NUM> being generally coaxial with the intermediate portion <NUM>. However, in other embodiments, the wires <NUM>, <NUM> may still be bent in unloaded configuration such as if the patient's anatomy prevents the sliders <NUM> from shifting the full distance across the through openings <NUM>. By comparing <FIG> and <FIG>, the end portions <NUM>, <NUM> wiggle or pivot from a transversely extending orientation relative to each other to the coaxial orientation relative to each other as the wires <NUM>, <NUM> shift from the loaded configuration to the unloaded configuration.

With reference to <FIG>, the wires <NUM>, <NUM> may be made of a super-elastic material such as nitinol which has a stress-strain graph <NUM>. The nitinol wires <NUM>, <NUM> have a first characteristic (e.g. spring constant) when they are biasing the sliders <NUM> in directions <NUM>, <NUM> (see <FIG>) toward the end portions <NUM> of the through openings <NUM> such as after the spacers <NUM> are removed from the bone plate <NUM>. However, the nitinol wires <NUM>, <NUM> have a second characteristic (e.g. spring constant) that is different than the first characteristic when the sliders <NUM> are shifted in directions <NUM>, <NUM> toward the end portions <NUM> of the through openings <NUM> such as if the bones <NUM>, <NUM> are being urged apart due to patient movement. With reference to <FIG>, the different first and second characteristics cause the wires <NUM>, <NUM> to provide a greater resistance force to movement of the sliders 18A, 18B in direction <NUM> and sliders 18C, 18D in direction <NUM> than the force the wires <NUM>, <NUM> apply against the sliders <NUM> to shift the sliders 18A, 18B in direction <NUM> and sliders 18C, 18D in direction <NUM>. The higher resistance to shifting of the sliders <NUM> in directions <NUM>, <NUM> causes the wires <NUM>, <NUM> to act as one-way slide control mechanisms that effectively limit sliding movement of the sliders <NUM> to directions <NUM>, <NUM> while inhibiting sliding movement of the sliders <NUM> in directions <NUM>, <NUM>.

The different characteristics of the nitinol wires <NUM>, <NUM> may be due to the stressinduced formation of some martensite in the superelastic nitinol of the wires <NUM>, <NUM> above the normal temperature of martensite formation. Because the martensite has been formed above its normal formation temperature, the martensite reverts immediately to undeformed austenite as stress is removed. Austenite is higher strength than martensite and is stronger against bending of the nitinol wires <NUM>, <NUM> back toward their loaded configuration.

For example, if the wires <NUM>, <NUM> start at position A in graph <NUM> when bone plate system <NUM> is secured to the bones <NUM>, <NUM>, removing the spacers <NUM> allows the wires <NUM>, <NUM> to shift the sliders <NUM> toward the end portions <NUM> of the through openings <NUM>. The moving of the sliders <NUM> in the unloading direction releases stress in the wires <NUM>, <NUM> and causes the stress and strain of the wires <NUM>, <NUM> to move toward position B. As the sliders <NUM> further compress the bones <NUM>, <NUM> together, the stress and strain of the wires <NUM>, <NUM> moves to position C in stress-strain graph <NUM>. However, if post-surgical patient movement imparts loading in direction <NUM> on the associated bone screw <NUM>, the wires <NUM>, <NUM> of the slider 18D resist this movement and the stress and strain within the wires <NUM>, <NUM> jumps to position D in the stress-strain graph <NUM>. The jump to the upper band of the stress-strain graph <NUM> indicates that the stress in the material is much higher which translates into greater resistance to bending of the wires <NUM>, <NUM> back toward their loaded configuration.

With reference to <FIG>, the sliders <NUM> and wires <NUM>, <NUM> of each slider are shown prior to assembly with the bone plate <NUM>. During assembly, the sliders <NUM> are inserted in direction <NUM> into the through openings <NUM>. The sliders <NUM> are positioned in their unloaded positions, i.e., at the end portions <NUM> of the through openings <NUM>.

Next, the wires <NUM>, <NUM> are provided in a straight, unloaded configuration. The end portions <NUM> of the wires <NUM>, <NUM> are advanced in direction <NUM> through apertures <NUM> of the bone plate <NUM>, through the passageways <NUM>, <NUM> of the sliders <NUM>, and into the through apertures <NUM> of the opposite side of the bone plate <NUM>. The wires <NUM>, <NUM> are thereby positioned so that the intermediate portion <NUM> of each wire <NUM>, <NUM> extends through the respective passageway <NUM>, <NUM>, the end portion <NUM> of each wire <NUM> is received in one of the through apertures <NUM>, and the end portion <NUM> of each wire <NUM>, <NUM> is received in one of the through apertures <NUM>.

The sliders <NUM> are then shifted in preloading directions <NUM>, <NUM> toward the loaded positions thereof, i.e., toward end portions <NUM> (see <FIG>) of the through openings <NUM>. Shifting of the sliders <NUM> in the preloading directions <NUM>, <NUM> loads or bends the wires <NUM>, <NUM> and creates gaps 64A (see <FIG>) between the sliders <NUM> and the laterally extending walls <NUM>, <NUM> of the bone plate <NUM>. The shifting of the sliders <NUM> in preloading directions <NUM>, <NUM> may be performed by a technician utilizing a tool or an automated machine as some examples.

With reference to <FIG>, to connect the spacers <NUM> to the bone plate <NUM>, the spacers <NUM> are generally advanced in a direction <NUM> into the gaps 64A between the sliders <NUM> and the nearby bone plate laterally extending walls <NUM>, <NUM> while the sliders <NUM> are held in the loaded position thereof by the technician or automated machine. Once the spacers <NUM> are positioned in the gaps 64A, the sliders <NUM> are released and the wires <NUM>, <NUM> of each slider <NUM> urge the sliders <NUM> against the spacers <NUM> which clamps the spacers <NUM> between the sliders <NUM> and the laterally extending bone plate walls <NUM>, <NUM>. The process of shifting the sliders <NUM> to the loaded position and connecting the spacers <NUM> to the bone plate <NUM> may be performed on all of the sliders <NUM> at once, or may be performed on fewer than all of the sliders <NUM> (e.g., one or more) at a time.

Regarding <FIG>, the bone plate <NUM> includes an end wall <NUM> opposite the laterally extending wall <NUM> and side walls <NUM>, <NUM> through which the apertures <NUM>, <NUM> extend. The apertures <NUM>, <NUM> have a varying profile throughout to accommodate the movement of the end portions <NUM>, <NUM> of the wires <NUM>, <NUM>. Further, each through opening <NUM> has a longitudinal axis <NUM> extending between the end portions <NUM>, <NUM> of the through opening <NUM>. Although the following discussion refers to through aperture <NUM>, it will be appreciated that the through aperture <NUM> is a mirror image of the through aperture <NUM> such that the following discussion also applies to through aperture <NUM>, wire end portion <NUM>, and side wall <NUM>.

The through aperture <NUM> includes a narrow portion <NUM> having a distance <NUM> thereacross and an enlarged portion <NUM> having a distance <NUM> thereacross that is larger than the distance <NUM>. The enlarged portion <NUM> provides clearance for the end portion <NUM> of the wire <NUM> to move from the oblique or transverse orientation thereof when the wires <NUM>, <NUM> are in the loaded configuration (see <FIG>) to the parallel or coaxial orientation when the wires <NUM>, <NUM> are in the unloaded configuration thereof (see <FIG>).

The side wall <NUM> also includes features that support the end portion <NUM> of the wires <NUM>, <NUM> while minimizing stress imparted to the wires <NUM>, <NUM>. For example, the side wall <NUM> includes an angled surface <NUM> that extends at an acute angle <NUM> relative to an axis <NUM> extending laterally through the apertures <NUM>, <NUM>.

With reference to <FIG> and <FIG>, the sliders <NUM> have a generally rectangular configuration and through openings <NUM> have a generally rectangular configuration that is longer than the sliders <NUM> to permit the sliders <NUM> and bone screws <NUM> therein to slide longitudinally within the through opening <NUM> along the bone plate <NUM>. The slider <NUM> includes a body <NUM> having lateral sides <NUM>, <NUM>. The sides <NUM>, <NUM> include flat surfaces <NUM>, <NUM> for facing flat surfaces <NUM>, <NUM> of the bone plate side walls <NUM>, <NUM> as shown in <FIG>. The passageways <NUM>, <NUM> of the slider <NUM> includes openings <NUM>, <NUM> that open to the sides <NUM>, <NUM> (see <FIG>). The facing flat surfaces <NUM>, <NUM> and <NUM>, <NUM> of the sliders <NUM> and the bone plate <NUM> resist turning of the sliders <NUM> within the through openings <NUM>.

Regarding <FIG>, the side walls <NUM>, <NUM> of the bone plate <NUM> include wall portions <NUM>, <NUM> above and below the wires <NUM>, <NUM> when the wires extend through the apertures <NUM>, <NUM>. The wires <NUM>, <NUM> support the sliders <NUM> within the through openings <NUM> of the bone plate <NUM> against movement of the sliders <NUM> in directions <NUM>, <NUM> out of the plane of the bone plate <NUM>. The wires <NUM>, <NUM> are made of a material and have an adequate diameter to be sufficiently strong in shear to resist the loading applied to the sliders <NUM> by the bone screws <NUM>.

With reference to <FIG>, the lateral sides <NUM>, <NUM> of the slider <NUM> extend longitudinally between front and rear sides <NUM>, <NUM>. Further, the passageways <NUM>, <NUM> extend through the slider <NUM> and include an angled surface <NUM> and a rounded surface <NUM> that lead into the passageways <NUM>, <NUM> from the sides <NUM>, <NUM>.

Turning to <FIG>, the passageway <NUM> includes enlarged side portions <NUM>, <NUM> for receiving the wire <NUM> and permitting the end portions <NUM>, <NUM> space to pivot or wiggle as the wire <NUM> straightens toward the undeflected configuration thereof. With reference to <FIG>, the passageway <NUM> of the slider <NUM> varies in size as the passageway <NUM> extends laterally across the slider <NUM> to provide support to the wire <NUM> when wire <NUM> is in deflected configuration thereof and provide clearance for the wire <NUM> as the wire <NUM> moves from the deflected configuration to the undeflected configuration. The passageway <NUM> includes enlarged side portions <NUM>, <NUM> and an intermediate portion <NUM>. The passageway <NUM> has a first distance <NUM> thereacross at the enlarged side portion <NUM>, a second distance <NUM> thereacross intermediate the enlarged portion <NUM> and the intermediate portion <NUM>, and a third distance <NUM> at the intermediate portion <NUM>. The distance <NUM> is greater than the distance <NUM> which is in turn greater than the distance <NUM>. Similar sizing exists at the enlarged side portions <NUM>.

The slider <NUM> includes a wall <NUM> that abuts against or is a close proximity to a laterally extending wall of the bone plate <NUM> such as walls <NUM>, <NUM> when the slider <NUM> is in the loaded position thereof. The slider <NUM> also includes the wall <NUM> extending around the through bore <NUM>. The wall <NUM> may extend generally straight laterally across the slider while the wall <NUM> includes an angled surface <NUM>, a rounded corner <NUM>, an intermediate support surface <NUM>, a rounded corner <NUM> and an angled surface <NUM> at the passageway <NUM>. The angled surfaces <NUM>, <NUM> each extend an angle <NUM> relative to the lateral axis <NUM> that extends straight through the passageway <NUM>.

Similarly, the passageway <NUM> includes the enlarged side portions <NUM>, <NUM> and a wall <NUM> extending generally laterally across the slider <NUM>. The slider <NUM> also includes the wall <NUM> having a rounded surface <NUM>, an intermediate support surface <NUM>, and a rounded surface <NUM>. The passageway <NUM> varies in size as the passageway <NUM> extends through the slider <NUM> including having a dimension <NUM> at the enlarged side portion <NUM> and a smaller distance <NUM> thereacross at an intermediate portion <NUM> of the passageway <NUM>.

<FIG> shows the wires <NUM>, <NUM> in the deflected or loaded configuration thereof wherein the end portions <NUM>, <NUM> of the wires <NUM>, <NUM> extend outward from the lateral sides <NUM>, <NUM> of the slider <NUM> for connecting to the bone plate <NUM>. In the loaded configuration, the wires <NUM>, <NUM> include outer intermediate portions <NUM>, <NUM> that extend along and are supported by the angled surfaces <NUM>, <NUM> and rounded surfaces <NUM>, <NUM>. The wires <NUM>, <NUM> further include the intermediate portions <NUM>, <NUM> that are supported, respectively, by the intermediate support surfaces <NUM>, <NUM>. Further, the rounded corners <NUM>, <NUM> and rounded surfaces <NUM>, <NUM> provide support without sharp corners which reduces stress in the wires <NUM>, <NUM>. Each wire <NUM>, <NUM> generally has one bend <NUM> with a shape complimentary to the either the surfaces <NUM>, <NUM>, <NUM> or the surfaces <NUM>, <NUM>, <NUM>. The walls <NUM>, <NUM> of the slider <NUM> may thereby be configured to compliment a desired amount of bend <NUM> of the wires <NUM>, <NUM> while limiting stress imparted to the wires <NUM>, <NUM> supported by the walls <NUM>, <NUM>.

With the wires <NUM>, <NUM> in the loaded configuration, the wires <NUM>, <NUM> each extend at an angle <NUM> relative to the lateral axis <NUM> of the passageways <NUM>, <NUM>. The angles <NUM> may be the same or different depending on a particular application. With respect to the wire <NUM>, the outer intermediate portion <NUM> is separated by a distance <NUM> from the wall <NUM> by a gap <NUM> which increases in size as the wire <NUM> extends away from the intermediate support surface <NUM> as shown in <FIG>. The gap <NUM> provides clearance for the outer intermediate portion <NUM> to move once the spacer <NUM> have been removed from the bone plate <NUM> and the wire <NUM> can straighten out. The wire <NUM> likewise has a gap from the wall <NUM> that varies as the wire <NUM> extends laterally outward.

With respect to <FIG>, the wires <NUM>, <NUM> are shown in the undeflected configuration such as after the spacer <NUM> has been removed from the bone plate <NUM>. The outer intermediate portions <NUM>, <NUM> of the wires <NUM>, <NUM> pivot in direction <NUM> into contact with the wall <NUM>, <NUM>. This causes a gap <NUM> to separate the outer intermediate portions <NUM>, <NUM> of the wire <NUM> from the angled surfaces <NUM>, <NUM> of the wall <NUM> of the slider <NUM>. The wire <NUM> is spaced from the wall <NUM> by a distance <NUM> that increases as the wire <NUM> extends laterally away from the intermediate support surface <NUM>. Likewise, the outer intermediate portions <NUM>, <NUM> of the wire <NUM> are spaced by a gap <NUM> from the curved surfaces <NUM>, <NUM> of the wall <NUM>.

Regarding <FIG> and <FIG>, each shoulder <NUM> of the spacer <NUM> defines a notch <NUM> that receives a corner <NUM> of the bone plate <NUM> when the spacer <NUM> is connected to the bone plate <NUM>. The shoulder <NUM> has a lower surface <NUM> that rests on the upper surface <NUM> of the bone plate <NUM>. The head <NUM> has a tapered surface <NUM> that extends downwardly from a circular upper surface <NUM> to a cylindrical, radially outer surface <NUM> of the head <NUM>. The surface <NUM> contacts the upper surface <NUM> of the bone plate <NUM> and the slider <NUM> and resist tilting or other movement of the spacer <NUM> which may lead to unintentional removal of the spacer <NUM> from the bone plate <NUM>, such as during handling of the bone plate <NUM> prior to being placed at the surgical site. Further, the flats <NUM>, <NUM> of the spacer <NUM> are normal to the biasing force and reactionary force imparted on the spacer <NUM> by the slider <NUM> and the bone plate <NUM> which facilitates secure clamping of the spacer <NUM> to the bone plate <NUM>.

The tapered surface <NUM> is configured to cam resilient fingers <NUM> of the spacer removal instrument <NUM> (see <FIG>) radially outward as the instrument <NUM> is connected to the spacer <NUM> and the resilient fingers <NUM> are advanced in direction <NUM> along the head <NUM>. Once the resilient fingers <NUM> have advanced past the cylindrical surface <NUM>, the resilient fingers <NUM> snap below the underside surface <NUM> of the head <NUM> of the spacer <NUM>. With the resilient fingers <NUM> below the underside surface <NUM> of the head <NUM>, the user may pull upward on the instrument <NUM> in direction <NUM> and withdraw the body <NUM> from between the slider <NUM> and the bone plate <NUM>. The movement of the instrument <NUM> in direction <NUM> engages the resilient fingers <NUM> with the underside surface <NUM> of the head <NUM> and draws the spacer <NUM> out from the gap 64A between the slider <NUM> and the bone plate <NUM>.

The body <NUM> of the spacer <NUM> includes a lower body portion <NUM> having a thickness <NUM> measured between the flats <NUM>, <NUM>. The thickness <NUM>, in combination with the geometry of the slider <NUM> and bone plate <NUM>, is selected to hold the wires <NUM>, <NUM> in the loaded configuration with the maximum desired deformation in the wires <NUM>, <NUM>.

With reference to <FIG>, the bone screws <NUM> each include the head portion <NUM> and a shank portion <NUM>. The shank portion <NUM> includes threads <NUM> for driving into bone. In one embodiment, the shank portion <NUM> is configured to be self-tapping. The head portion <NUM> includes a rotary drive structure, such as a socket <NUM>, that receives a screwdriver such as a hexa-lobed screwdriver. The head portion <NUM> further includes a curved lower surface <NUM> for engaging a seating surface <NUM> (see <FIG>) of the slider <NUM>.

With reference to <FIG>, the spacer removal instrument <NUM> includes a handle assembly <NUM> and a shaft assembly <NUM>. The shaft assembly <NUM> includes a distal end portion <NUM> configured to engage one of the heads <NUM> of the spacers <NUM> and a proximal end portion <NUM> connected to the handle assembly <NUM>. The handle assembly <NUM> includes a stationary grip <NUM> and a handle <NUM> pivotally connected to the stationary grip <NUM> by a pin <NUM>.

With reference to <FIG>, the shaft assembly <NUM> includes an outer sleeve <NUM> mounted to the stationary grip <NUM> and an inner shaft <NUM> connected to the handle <NUM>. The inner shaft <NUM> includes a rim <NUM> having the one or more resilient fingers <NUM> mounted thereto. The resilient fingers <NUM> are mounted to the inner shaft <NUM> with pins that extend through openings <NUM> (see <FIG>) of the resilient fingers <NUM>. In another embodiment, the inner shaft <NUM> and the one or more resilient fingers <NUM> have an integral construction rather than being assembled. The inner shaft <NUM> also includes a cannula <NUM> for holding the spacers <NUM> in a line within the cannula <NUM> as the spacers <NUM> are removed one by one from the bone plate <NUM>. In another embodiment, the grip <NUM> may be movable and the handle <NUM> may be fixed or both the grip <NUM> and the handle <NUM> may be movable to operate the instrument <NUM>.

With reference to <FIG>, a method (not part of the claimed invention) is provided for removing a spacer <NUM> from a bone plate <NUM> of a bone plate system <NUM> (see <FIG>) using the instrument <NUM>. First, a user holds the instrument <NUM> so that the opening <NUM> of the inner shaft <NUM> is adjacent a head <NUM> of the spacer <NUM>. The user advances the instrument <NUM> in direction <NUM> toward the bone plate <NUM> until the head <NUM> enters the opening <NUM> and the resilient fingers <NUM> snap below the head <NUM> of the spacer <NUM>. The user then pivots the grip <NUM> in direction <NUM> (see <FIG>) while pressing the instrument <NUM> against the bone plate <NUM>. The pivoting of the grip <NUM> causes the inner shaft <NUM> to shift in direction <NUM> relative to the outer sleeve <NUM> and engages the resilient fingers <NUM> with the underside of the head <NUM>. As the inner shaft <NUM> shifts in direction <NUM>, a rim <NUM> of the outer sleeve <NUM> contacts the bone plate <NUM> and one of the sliders <NUM> therein. As shown in <FIG> and <FIG>, the user's moving of the handle <NUM> toward the stationary grip <NUM> causes the inner shaft <NUM> to pull the spacer <NUM> in direction <NUM> outward from the bone plate <NUM>.

Once the spacer <NUM> has been removed from the bone plate <NUM>, the user releases the handle <NUM> and the handle <NUM> may be biased back toward its initial position by a spring of the instrument <NUM>. With reference to <FIG>, the user then positions the instrument <NUM> at a second spacer <NUM>. Although the first spacer <NUM> is held by the resilient fingers <NUM> within the cannula <NUM>, the user may simply press the instrument <NUM> in direction <NUM> onto the second spacer <NUM> which causes the second spacer <NUM> to shift the first spacer <NUM> farther into the cannula <NUM> and beyond the resilient fingers <NUM> as shown in <FIG>. The instrument <NUM> is pressed in direction <NUM> until the resilient fingers <NUM> snap below the head <NUM> of the second spacer. Next, the user pivots the handle <NUM> toward the stationary grip <NUM> which causes the inner shaft <NUM> to shift in direction <NUM>, the outer sleeve to engage the bone plate <NUM>/slider <NUM>, and the inner shaft <NUM>/resilient fingers <NUM> to pull the second spacer <NUM> out of the bone plate <NUM> as shown in <FIG> and <FIG>.

With reference to <FIG>, a bone plate system <NUM> is provided that includes a bone plate <NUM> and slider assemblies <NUM> that receive bone screws <NUM> and are shifted along throughbores <NUM> of the bone plate <NUM> by biasing assemblies <NUM> once spacers <NUM> of the bone plate system <NUM> have been removed. The slider assemblies <NUM> include sliders 604A, 604B and 604C. The slider assemblies 604A, 604B are identical to the slider assemblies <NUM> discussed above. However, the slider assembly 604C is different and includes a slider <NUM> having two throughbores <NUM> for receiving two bone screws <NUM>.

With reference to <FIG>, the slider assembly 604C includes the slider <NUM> and one or more resilient members, such as wires <NUM>, <NUM>. The wires <NUM>, <NUM> each have end portions <NUM>, <NUM> that extend outward from sides <NUM>, <NUM> of the slider <NUM> and engage through apertures <NUM> of the bone plate <NUM>.

With reference to <FIG> and <FIG>, due to the lateral extent of the slider <NUM>, the slider <NUM> has a curvature to compliment the curvature of an outer surface of a bone while minimizing interference with surrounding tissues. In the illustrated embodiment, the slider <NUM> includes a concave lower surface <NUM> and a convex upper surface <NUM>. Due to the curvature of the slider <NUM>, the wires <NUM>, <NUM> have a complex curvature throughout the slider <NUM>. More specifically and with reference to <FIG>, the slider <NUM> includes passageways <NUM>, <NUM> and the wires <NUM>, <NUM> extend upwardly and to the left (as seen in <FIG>) into the passageways <NUM>, <NUM> at the side <NUM>.

With reference to <FIG>, the passageways <NUM>, <NUM> each include an outer enlarged portion <NUM> and a narrow intermediate portion <NUM>. The slider <NUM> includes a wall <NUM> extending around each throughbore <NUM> and the wall <NUM> includes an angled surface <NUM>, curved corner <NUM>, and an intermediate support surface <NUM>. The slider <NUM> includes a wall <NUM> opposite the wall <NUM> and across the passageway <NUM>. As discussed above with respect to the sliders <NUM>, the outer enlarged portion <NUM> of the passageway <NUM>, <NUM> permits movement of an outer intermediate portion <NUM> of the wires <NUM>, <NUM> as the wires <NUM>, <NUM> straighten from a loaded configuration to an unloaded configuration and the outer intermediate portions <NUM> pivot in direction <NUM>. The wires <NUM>, <NUM> include intermediate portions <NUM> that contain a bend <NUM> (see <FIG>) out of the page in <FIG> as well as inner intermediate portions <NUM> that are connected to the outer intermediate portions <NUM> by bends <NUM> generally in the plane of the cross section taken of <FIG>.

With reference to <FIG>, the passageway <NUM> is shown and it will appreciated that the passageway <NUM> is similar in many respects. More specifically, the passageway <NUM> includes a first passageway portion <NUM> extending inward from side <NUM> and having an axis <NUM>. The passageway <NUM> includes a second passageway portion <NUM> extending inward from the side <NUM> and having an axis <NUM> therein. There is an angle <NUM> between the axes <NUM>, <NUM>. The angle <NUM> forms a bend <NUM> (see <FIG>) in the intermediate portion <NUM> of the wire <NUM> to provide enough material in a lower wall <NUM> of the slider <NUM> and accommodate the concave lower surface <NUM>. The slider <NUM> includes an upper wall <NUM> having a through opening <NUM> therein that permits viewing of the wire <NUM>. Through opening <NUM> may be formed during manufacture of the slider <NUM> by a machine tool that enters the passageway <NUM> from above and machines out material as needed. In other embodiments, the through opening <NUM> is not utilized such as if the slider <NUM> is produced using additive manufacturing. The lower wall <NUM> includes an inclined surface <NUM> in the first passage portion <NUM> to support one of the inner intermediate portions <NUM> of the wire <NUM> and an inclined surface <NUM> in the second passageway portion <NUM> to support the other inner intermediate portion <NUM>. Likewise, the upper wall <NUM> includes inclined surfaces <NUM>, <NUM> which together with the lower inclined surfaces <NUM>, <NUM> maintain the bend <NUM> in the intermediate portion <NUM> whether the wire <NUM> is in the loaded or unloaded configuration thereof.

With reference to <FIG>, the wire <NUM> is shown removed from the slider <NUM> and is in the loaded configuration thereof. In the loaded configuration, the outer intermediate portion <NUM> is at an angle <NUM> relative to the inner intermediate portion <NUM> and forms two bends <NUM> in the wire <NUM>. Whereas <FIG> is a top plan view, <FIG> is a rear elevation view of the wire <NUM> in the loaded configuration thereof. As discussed above with respect to <FIG>, the first passageway portion <NUM> and the second passageway portion <NUM> create the bend <NUM> in the intermediate portion <NUM> of the wire <NUM> to provide clearance for the concave lower surface <NUM> of the slider <NUM>. The bend <NUM> positions the outer intermediate portions <NUM> at an angle <NUM> relative to one another. Thus, when the wires <NUM>, <NUM> are in the loaded configuration, each wire <NUM>, <NUM> has three bends including the two bends <NUM> and the bend <NUM>. Once the spacer <NUM> has been removed from the bone plate <NUM> and the pins <NUM>, <NUM> urge the slider <NUM> to an unloaded position thereof, the bends <NUM> straighten out in a manner similar to the straightening of the bend <NUM> as one goes from <FIG>. However, even once the slider <NUM> has shifted to the unloaded position, the passageways <NUM>, <NUM> maintain the bend <NUM> in the intermediate portions <NUM> of the wires <NUM>, <NUM> because the inner intermediate portions <NUM> are constrained against movement unlike the outer intermediate portions <NUM>.

With reference to <FIG>, the wire <NUM> is shown in a side elevational view to illustrate how each of the bends <NUM> orients the outer intermediate portion <NUM> thereof to extend transversely to the inner intermediate portions <NUM>. Further, the bend <NUM> provides the vertical component (as shown in <FIG>) of the extent of both the outer intermediate portion <NUM> and the inner intermediate portion <NUM> of the wire <NUM>. When the spacers <NUM> are removed from the bone plate <NUM>, the outer intermediate portions <NUM> pivot in direction <NUM>.

With reference to <FIG>, the bone plate system <NUM> is similar in many respects to the bone plate system <NUM> discussed above. The bone plate system <NUM> includes a bone plate <NUM> having through openings <NUM> that receive slider assemblies <NUM>. The slider assemblies <NUM> include sliders <NUM> having throughbores <NUM> that receive bone screws <NUM>. The bone plate system <NUM> includes spacers <NUM> that may be removed from the bone plate <NUM> to permit the slider assemblies <NUM> to shift to unloaded positions which compresses bones connected to the bone screws <NUM>. One difference between the bone plate system <NUM> and the bone plate system <NUM> discussed above is that the bone plate <NUM> has a dog bone-shaped configuration with enlarged end portions <NUM>, <NUM> and a narrowed intermediate portion <NUM>. The narrowed intermediate portion <NUM> forms notches <NUM>, <NUM> on opposite sides of the bone plate <NUM>. Each end portion <NUM>, <NUM> includes two throughbores <NUM> to receive two slider assemblies <NUM>.

Regarding <FIG>, a bone plate <NUM> is provided that is similar in many respects to the bone plate <NUM> discussed above. The bone plate <NUM> may be utilized in the bone plate system <NUM> instead of the bone plate <NUM>. For example, the bone plate <NUM> includes through openings <NUM> configured to receive the slider assemblies <NUM>. The bone plate <NUM> includes side walls <NUM> with apertures <NUM> for receiving end portions of the wires <NUM>, <NUM> of the slider assemblies <NUM>. Regarding <FIG> and <FIG>, each aperture <NUM> includes an angled surface <NUM> for supporting the associated wire <NUM>, <NUM> and providing a more gradual bend of the wire <NUM>, <NUM> when the sliders <NUM> are held in the loaded configuration in the through openings <NUM> by the spacers <NUM>. Regarding <FIG>, the bone plate <NUM> has a varying thickness between upper and lower surfaces thereof including a thinner intermediate portion <NUM> between thicker side portions <NUM>. The thinner intermediate portion <NUM> may include, for example, a generally concave surface portion. Conversely, the lower surface <NUM> of the bone plate <NUM> may have a generally concave surface portion. The thinner intermediate portion <NUM> provides a reduced thickness along the midline of the plate which may improve interaction with surrounding tissues for some patients.

Claim 1:
A bone plate system (<NUM>) comprising:
a bone plate (<NUM>);
a plurality of elongated through openings (<NUM>) of the bone plate (<NUM>), each elongated through opening (<NUM>) having a pair of end portions (<NUM>, <NUM>) across the through opening (<NUM>) from each other;
a plurality of bone screws (<NUM>) each having a head portion (<NUM>) and a shank portion (<NUM>), the shank portion (<NUM>) configured to be driven into bone;
a plurality of sliders (<NUM>) in the elongated through openings (<NUM>) and having throughbores (<NUM>) configured to receive the head portions (<NUM>) of the bone screws (<NUM>), the sliders (<NUM>) and the bone screw head portions (<NUM>) received therein being shiftable within the elongated through openings (<NUM>) relative to the bone plate (<NUM>);
at least one resilient member for being configured to apply a biasing force to the slider (<NUM>) to urge the slider (<NUM>) toward one end portion (<NUM>) of a respective through opening (<NUM>); and
at least one actuator having an interference position in which the actuator inhibits shifting of the sliders (<NUM>) toward the one end portion (<NUM>) of the respective through openings (<NUM>) and a clearance position in which the actuator permits the at least one resilient member to urge the sliders (<NUM>) and the bone screws (<NUM>) received therein along the through openings (<NUM>) of the rigid bone plate (<NUM>) and toward the one end portion (<NUM>) of the through openings (<NUM>).