Patent ID: 12186204

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of explanation and not limitation, details and descriptions of certain preferred embodiments are hereinafter provided such that one having ordinary skill in the art may be enabled to make and use the invention. These details and descriptions are representative only of certain preferred embodiments, however a myriad of other embodiments which will not be expressly described will be readily understood by those having skill in the art upon a thorough review hereof. Accordingly, any reviewer of the instant disclosure should interpret the scope of the invention by the claims, and such scope shall not be limited by the embodiments described and illustrated herein.

As one with skill in the art may appreciate, the bone fixation system10may include any device intended to be placed adjacent a bone within the human body including: plates and interbody spacers. The bone fixation system may be constructed out of any suitable biocompatible materials including, for example, autograft, allograft, titanium, cobalt chrome, carbon fiber, PEEK, PEK, PEKK or a combination thereof, or any other material known in the field of bone fixation technology.

FIGS.1-4illustrate an exemplary embodiment of a bone fixation system including a bone plate12, a plurality of fasteners16and a polymeric element14. According this exemplary embodiment, the bone plate12includes a plurality of apertures17each dimensioned to receive a fastener16there through. The bone plate12further includes a recess18adjacent each aperture17, the recess18being configured to house the polymeric element14. As shown in this embodiment, each recess18corresponds to a single aperture17. However, plate configurations are also contemplated wherein a single recess is in communication with two, three, four or more apertures.

According to one aspect, the fastener16may include any device intended to secure an implant with respect to a bone structure of a patient. By way of example only a fastener may include, but is not limited to, a bone anchor, a bone screw, a spike, a staple or a blade. As illustrated in the exemplary embodiment inFIG.4, the fastener16is a bone screw that includes a head and a threaded shank.

According to another aspect, the polymeric element is at least partially comprised of a thermoplastic material. According to the exemplary embodiment, the thermoplastic material that can transition from a generally solid state (e.g. not flowable) flowable state when the thermoplastic material is heated. In particular, the thermoplastic material transitions from a solid state at room temperature to a flowable state upon application of ultrasonic vibration to the polymeric element. According to the exemplary embodiment, the bone fixation system10pre-assembled prior to use in surgery such that the polymeric element14is housed within the recess18of the plate12. The polymeric element14may be dimensioned to correspond to the shape of the recess17in the bone plate12to which the polymeric element14is applied. According to this embodiment, the polymeric element14has an annular shape that corresponds generally to the shape of the aperture17and has an inner diameter14athat is dimensioned to allow passage of the fastener through the center of the polymeric element.FIG.3shows a perspective view of a polymeric element14having an inner diameter14adimensioned to receive a fastener16. The size of the inner diameter14amay be chosen depending on the type and size of fastener16used. However, preassembly of the plate12and polymeric element14is not required, and the polymeric element(s)14may be provided separately to be assembled, for example, during surgery.

In some embodiments, a keyed portion13or any portion of the polymeric element14, remain accessible even with a fastener16inserted through a corresponding aperture17. This accessible portion24of the polymeric element is sized to allow sufficient contact with the distal tip45of a sonotrode40, in order to apply ultrasonic vibrations to the polymeric element thereby causing the thermoplastic component(s) to become heated and consequently transition to a flowable state.

In some embodiments, the plate12may include a corresponding anti-rotation groove13, (seeFIG.2) such that when the polymeric element14is placed adjacent to the aperture17, the anti-rotation feature15of the polymeric element14will complementarily fit within the anti-rotation feature13of the plate12. This interaction may prevent the polymeric element14from rotating when a fastener16is inserted through the apertures17.

During use, a bone plate is implanted adjacent a patient's bone. According to the exemplary embodiment, the polymeric element is pre-installed in the recess in the bone plate prior to implantation in a patient. Upon placement of the bone plate adjacent the patient's bone, at least one fastener is inserted through an aperture and into the patient's bone to secure the bone plate to the bone. After placement of the one or more fasteners, the plate may be secured with respect to the bone of a patient, and the surgeon can ultrasonically weld the fasteners to the plate. In doing so, the surgeon may for example, introduce the distal tip of a sonotrode to the thermoplastic element. Application of ultrasonic vibration from the sonotrode to the polymeric element causes the thermoplastic component(s) to heat up and consequently become flowable. The flowable thermoplastic material is then allowed to flow into the aperture and infiltrate the space in and/or around the proximal end of the fastener within the aperture. The polymeric element is then allowed to cool and return to a solid state, thereby preventing the fastener from rotating and/or translating in the aperture of the plate. According to one aspect, once the polymeric element has infiltrated the space in and/or around the proximal end of the fastener, it is actively cooled to a solid state. According to another aspect, thermoplastic material may flow into grooves on the fastener, or over the heads of the fasteners. Additionally, thermoplastic material may flow within the keyed groove of the plate. In an alternative method, the polymeric element is provided separately from the bone plate, and is applied to the bone plate after the steps of applying the bone plate to the patient's bone and inserting the fasteners through the apertures in the bone plate.

FIG.4shows a cross-sectional side view of a bone fixation system10in accordance with the first embodiment, the bone fixation system10shown including at least one fastener16inserted there through, with a portion of a polymeric element14disposed between the fastener16and the plate12. The polymeric element14is shown securing the bone fixation device16relative to the plate12.

FIGS.5-10illustrate an alternative exemplary embodiment, having many of the same features as the embodiment described above and shown inFIGS.1-4.FIG.5shows perspective view of a bone fixation system20in accordance with a second embodiment, the bone fixation system20shown including an intervertebral spacer22having a wall21that includes at least one aperture27there through. According to the exemplary embodiment shown inFIG.5, the spacer22has an anterior wall21with a plurality of apertures27dimensioned to receive bone fasteners36. Each of the apertures27has a corresponding recess28dimensioned to house the polymeric element24. It is also contemplated that wall21of the spacer22can include fewer recesses than apertures, wherein a single recess is in communication with more than one aperture.

According to this exemplary embodiment,FIG.7shows a perspective view of the spacer having a one or more apertures disposed on an anterior wall21thereof. The spacer22is shown having a top surface, a bottom surface, and one or more walls forming a fusion aperture. The top surface is shown including anti-migration features to engage the endplates of the vertebral bodies adjacent the intervertebral space into which the spacer is inserted. The fusion aperture is configured to receive bone graft, or bone graft substitute material therein, to promote fusion across the disc space.

In some embodiments, the polymeric element24may come preinstalled adjacent to the aperture27of the spacer22. In other embodiments, the polymeric element may come preinstalled adjacent to the fastener26. In still some other embodiments, the polymeric element24may be provided separately from the intervertebral spacer and positioned as need to secure to secure the fastener(s)26with respect to the spacer22during surgery.

In some embodiments, at least a portion of the polymeric element24remains exposed after a fastener26is inserted through an aperture27of the spacer22. As described in the previous embodiment, the distal tip of a sonotrode is applied to the exposed portion of the polymeric element to transmit ultrasonic vibrations to the polymeric element, causing it to heat up and transition to a flowable state. Additionally, an exposed portion of the polymeric element24may be achieved for e.g.: by creating a channel in the spacer22, creating a channel in the fastener26, or including an anti-rotation feature on the polymeric element24, similar to the anti-rotation feature of the first embodiment.

During use, the bone fixation device according to the embodiment illustrated inFIGS.5-10is installed in a similar method. Specifically, the polymeric element(s) are pre-installed in recesses in the aperture(s) of the spacer and the spacer is introduced into the intervertebral space of a patient. Upon desired placement of the spacer, at least one fastener is inserted into an aperture in the spacer. After insertion of the fastener, the distal tip of a sonotrode is applied to the polymeric element to transmit ultrasonic vibrations to the polymeric element, causing the polymeric element to heat up and transition to a flowable state. The flowable polymeric element is allowed to flow into the space in the aperture adjacent to the proximal end of the fastener, and allowed to cool to a solid state. Once in a solid state, the polymeric element prevents rotation and/or translation of the fastener with respect to the spacer. According to an alternative method, the polymeric element is provided separately from the spacer, and is applied to the aperture of the spacer after the fastener has been inserted.

FIGS.11-13illustrate a bone fixation system30in accordance with a third embodiment, the bone fixation system30is used in the same way and includes substantially the same features as shown in the exemplary embodiment ofFIGS.5-10, but further including a modular intervertebral spacer including a body32, and a detachable wall33, the detachable wall33including a plurality of apertures dimensioned to receive a plurality of fasteners37configured to secure the modular intervertebral spacer in an intervertebral space of a patient The detachable wall33includes a plurality of recesses38, each recess38adjacent to and in communication with two apertures37. Each recess38is configured to house a polymeric element34therein.

In some embodiments, the modular intervertebral spacer system32,33may include any spacer system having two or more parts, wherein two or more of the parts are joined together to form a unitary spacer body. In use, the modular intervertebral spacer may be pre-assembled prior to insertion, or the body32and the detachable wall33may be inserted separately. The body and detachable may be comprised of the same material or different materials. By way of example only, the body32may be constructed of a plastic material and the detachable wall33may be constructed of titanium or other suitable medical grade metal, or vice versa.

FIG.14shows a diagram of an exemplary sonotrode40configured to apply ultrasonic vibrations to cause the polymeric element to transition from a solid state to a flowable state. The ultrasonic vibrations may be created by a series of components, for example: a power supply, a converter, a booster, and a horn.

The power supply may receive an electrical line voltage and convert it to an operating frequency (e.g. 20 kHz). This electrical energy may be sent through a radio-frequency cable to a converter. The converter may use piezoelectric ceramics to convert the electrical energy to mechanical vibrations at an operating frequency of the power supply. This mechanical vibration may be increased or decreased depending on the configuration of the booster and horn. Depending on the polymeric materials used in the parts.

In operation, mechanical vibrations may be delivered to the parts to be welded. The parts also may be put under a mechanical load. Under this load, the mechanical vibrations may be transmitted to the interface between the material surfaces, which focuses the vibration to create intermolecular and surface friction. This friction creates heat and a subsequent transition from solid to liquid. The solid may then solidify into a welded bond.

Now, although particular features and embodiments have been described in an effort to enable those with skill in the art to make and use the claimed invention, it should be understood that several variations, alterations or substitutions can be achieved to arrive at a container with integrated dome applicator and hinged cap. Nothing in this description shall be construed as limiting the spirit and scope of the invention as set forth in the appended claims, below.