Patent Description:
Spinal fusion is a surgical procedure to correct problems relating to the human spine such as degenerative disc disease (DDD), spondylolisthesis, recurrent disc herniation, etc. It generally involves removing damaged disc and bone from between adjacent vertebrae and inserting bone graft material that promotes bone growth. As the bone grows, the adjacent vertebrae join, or fuse, together. Fusing the bones together can help make that particular area of the spine more stable and help reduce problems related to nerve irritation at the site of the fusion. Fusions can be done at one or more segments of the spine.

In an interbody fusion procedure, the nucleus pulposus and/or the annulus fibrosus that compose the intervertebral disc at the point of the damage are removed and an implant configured in shape and dimension is placed in the disc space to restore the distance between adjacent vertebrae to a proper condition. Surgical approaches to implement interbody fusion vary, and access to the patient's vertebral column can be made through the abdomen or back. One surgical method for accomplishing lumbar spinal fusion in a less invasive way involves accessing the vertebral column through a small incision on the posterior side where the surgeon removes a portion of bone and joint at the back and side of the vertebrae. These sections of bone and joint are called, respectively, the lamina and the facet joint. This procedure is known as transforaminal or lateral lumbar interbody fusion. This technique allows the surgeon to insert bone graft and spacer into the disc space from a unilateral approach laterally without having to forcefully retract the nerve roots, which can reduce injury and scarring around the nerve roots as compared to a more traditional posterior procedure.

Conventionally, once the intervertebral disc is removed from the body, the surgeon typically forces different trial implants between the vertebral bodies of the specific region to determine the size of the implant for maintaining a proper distance between the adjacent vertebrae. A proper angle between the vertebral bodies also must be maintained to accommodate the natural curvature of the spine e.g. the lordosis. Therefore, during selection of a fusion device for implantation, both intervertebral disc height and lordosis must be considered. Traditional implant devices are often pre-configured to have top and bottom surface angles to accommodate the natural curvature of the spine. It is unlikely or difficult that these values can be determined precisely prior to the operation. Further, in implementing a trial-and-error approach to sizing and fitting the interbody fusion device into the target region for geometric configuration, the patient is subjected to significant invasive activity. If a hyperlordotic sagittal profile configuration (≥<NUM>°) is set or supplemental fixation for the lumbosacral levels is desired, the surgeon may place a spinal construct in the form of anterior column fixation such as an additional plate and screw assembly to prevent possible movement or migration of the fusion device in the intervertebral disc space and/or to provide temporary stabilization of the anterior column of the spine during the spinal fusion process until arthrodesis takes place. This can require the surgeon to perform a secondary surgery after placing the fusion device, which in turn would lengthen the overall surgery time leading to more potential blood loss and complications with anesthesia for the patient.

The apparatus comprises an interbody fusion device and a fixation assembly. The fixation assembly may include one or more modular fixation plates insertable and attachable to the interbody fusion device in situ and one or more fasteners to stabilize and prevent migration of the interbody fusion device between adjacent vertebral bodies.

The fixation assembly may include a single fixation plate insertable and attachable to the interbody fusion device in situ and two or more fasteners to stabilize and prevent migration of the interbody fusion device between adjacent vertebral bodies. Optionally, the single fixation plate provides supplemental fixation of adjacent vertebrae.

The fixation assembly may include a single fixation plate insertable and attachable to the interbody fusion device in situ and two or more fasteners to stabilize and prevent migration of the interbody fusion device between adjacent vertebral bodies. The single fixation plate can be rotated or angled relative to the interbody fusion device in situ and can provide supplemental fixation of adjacent vertebrae.

The apparatus comprises an interbody fusion device and a fixation assembly for stabilizing and preventing migration of the interbody fusion device between adjacent vertebral bodies. The fixation assembly may include one or more fixation plates integrally formed with the interbody fusion device and one or more fasteners.

This Summary is provided to introduce selected embodiments in a simplified form and is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The selected embodiments are presented merely to provide the reader with a brief summary of certain forms the invention might take and are not intended to limit the scope of the invention. Other aspects and embodiments of the disclosure are described in the section of Detailed Description. The invention is as claimed with independent claim <NUM>.

These and various other features and advantages of the disclosure will become better understood upon reading of the following detailed description and the appended claims in conjunction with the accompanying drawings, where:.

With reference to <FIG>, where like reference numerals denote like parts, various embodiments of spinal systems and interbody fusion devices with fixation will now be described. It should be noted that the figures are only intended to facilitate the description of embodiments and not as an exhaustive description or a limitation on the scope of the disclosure. Further, certain specific details are shown in the figures in order to provide a thorough understanding of various embodiments of the disclosure. One skilled in the art will understand that the claimed invention may be practiced without these details. In other instances, well-known components, structures, or steps associated with the apparatuses, systems, and methods of the disclosure may not be shown or described in detail to avoid unnecessarily obscuring the description of embodiments of the disclosure. It should also be noted that certain aspects or features described in conjunction with a particular embodiment are not necessarily limited to that embodiment and can be practiced in any other embodiments.

In general, various embodiments of apparatuses or systems for treating spinal diseases comprise an interbody fusion device and a fixation assembly. The interbody fusion device can be placed between adjacent vertebrae in a region of a patient's spinal column. The configuration of the interbody fusion device can be adjusted to provide e.g. an expanded, a lordotic, kyphotic, hyperlordotic, or hyperkyphotic configuration suitable for treatment of the patient. The fixation assembly provides stabilization and prevents migration of the interbody fusion device in the expanded and/or lordotically adjusted configuration to promote safe body fusion. Alternatively, or additionally, the fixation assembly provides orthotic support or supplemental fixation to hold the adjacent vertebrae in place, which may be needed for treating certain spinal diseases. For ease of description of the disclosure, the phrase "interbody fusion device with fixation" may be used to refer to an apparatus including an interbody fusion device and a fixation assembly for stabilizing and preventing migration of the interbody fusion device; the phrase "spinal system" may be used to refer to a system including an interbody fusion device and a fixation assembly for stabilizing and preventing migration of the interbody fusion device and/or providing supplemental fixation to hold adjacent vertebrae in place.

The interbody fusion device included in the spinal systems and apparatuses of the disclosure may be any suitable fusion device. The interbody fusion device is a dual-axis adjustable fusion device. A dual-axis adjustable interbody fusion device includes two driving mechanisms that can be operated separately, independently, or simultaneously in situ to adjust the configuration of the interbody fusion device with a height and/or shape suitable for treating the patient. By way of example, the configuration of a dual-axis interbody interbody fusion device placed between adjacent vertebrae can be adjusted by operating the two driving mechanisms along the anterior and/or posterior side of the patient respectively to achieve a desired sagittal balance or correct sagittal imbalance for the patient. Alternatively, the configuration of a dual-axis adjustable interbody fusion device placed between adjacent vertebrae can be adjusted by operating the driving mechanisms along the lateral and/or contra-lateral side of the patient to achieve a desired coronal balance or correct coronal imbalance for the patient.

The dual-axis adjustable interbody fusion device includes a housing, a first wedge member, a second wedge member, a first drive shaft, and second drive shaft. The housing may include a first shell member and a second shell member. The first and second shell members engage the first wedge member along a first lateral area of the housing and engage the second wedge member along a second lateral area of the housing. The first wedge member is provided with a through-opening configured to allow the first drive shaft to pass. The second wedge member is provided with a through-opening configured to allow the second drive shaft to pass. The first and second wedge members may be tapered members. Example tapered members include but are not limited to rotatable tapered screws and slidable tapered plates.

The first drive shaft is operable to drive the first wedge member along the first lateral area of the housing, and the second drive shaft is operable to drive second wedge member along the second lateral area of the housing, causing the first and second shell members to move relative to each other thereby expanding the interbody fusion device. The first and second drive shafts may be independently operated to drive the first and second wedge members to different positions, causing the expansion of the interbody fusion device along the first lateral area of the housing to a degree different from a degree of the expansion of the interbody fusion device along the second lateral area of the housing.

The first and second wedge members may be tapered members configured to slide along the first and second lateral sides of the housing to expand or contract the interbody fusion device. Alternatively, the first and second wedge members may be screw members having threads configured to rotate and move along the first and second lateral sides of the housing to expand or contract the interbody fusion device. By way of example, the interbody fusion device may comprise a first pair of screw members and a second pair of screw members. The first shell member may comprise a plurality of individual riser members, and the second shell member may comprise a plurality of individual riser members. The plurality of individual riser members of the first shell member and the plurality of individual riser members of the second shell member may define a first tracking run along the first lateral area of the housing and a second tracking run along the second lateral area of the housing. The first drive shaft may be operable to rotate the first pair of screw members allowing the first pair of screw members to travel along the first drive shaft and move on the first tracking run. The second drive shaft may be operable to rotate the second pair of screw members allowing the second pair of screw members to travel along the second drive shaft and move on the second tracking run.

Various embodiments of interbody fusion devices are described in <CIT>, <CIT>, and <CIT> entitled "Expandable and Adjustable Lordosis Interbody Fusion System.

<FIG> show an example dual-axis adjustable interbody fusion device <NUM> which can be used in the spinal systems or apparatus according to embodiments of the disclosure. As shown, the dual-axis adjustable interbody fusion device <NUM> includes an expandable housing <NUM>, a first pair of screw members 14a, 14b, a second pair of screw members 16a, 16b, a first drive shaft <NUM>, and a second drive shaft <NUM>. The first pair of screw members 14a, 14b may each be provided with a through-opening configured to allow the first drive shaft <NUM> to pass and engage with the first pair of screw members 14a, 14b. The second pair of screw members 16a, 16b may each be provided with a through-opening configured to allow the second drive shaft <NUM> to pass and engage with the second pair of screw members 16a, 16b.

The housing <NUM> includes a first or inferior shell member <NUM> and a second or superior shell member <NUM>. The inferior shell member <NUM> may include a plurality of individual riser members <NUM> (<FIG>). The superior shell member <NUM> may include a plurality of individual riser members <NUM> (<FIG>). The plurality of individual riser members <NUM>, <NUM> of the inferior and superior shell members <NUM>, <NUM> may define a first step tracking run <NUM> along a first lateral area <NUM> of the housing <NUM> and a second step tracking run <NUM> along a second lateral area <NUM> of the housing <NUM> (<FIG>). The height of the plurality of individual riser members <NUM>, <NUM> may change along the first and second step tracking runs <NUM>, <NUM>. For example, the height of the plurality of individual riser members <NUM>, <NUM> of each of the first and second step tracking runs <NUM>, <NUM> may increase from a central portion <NUM> of the step tracking extending distally from the central portion. The first and second pairs of screw members 14a-14b and 16a-16b may each comprise a helical thread having a thickness configured to fit in the gaps between adjacent individual riser members.

The first drive shaft <NUM> is operable to rotate the first pair of screw members 14a, 14b, causing the first pairs of screw members 14a, 14b to move on the individual riser members <NUM>, <NUM> along the first step tracking run <NUM>. The second drive shaft <NUM> is operable to rotate the second pair of screw members 16a, 16b, causing the second pair of screw members 16a, 6b to move on the individual riser members <NUM>, <NUM> along the second step tracking run <NUM>. In response to the rotation of the first and second pairs of screw members 14a-14b and 16a-16b, the inferior and superior shell members <NUM>, <NUM> may move relative to each other, effecting an expansion of the housing <NUM> or a contraction of the housing <NUM> from the expansion by reversing the rotation of the first and/or second pairs of screw members. The first and second drive shafts <NUM>, <NUM> may be operable independently of each other. Therefore, the degree of expansion or contraction of the first lateral area <NUM> of the housing <NUM> is independently adjustable relative to the degree of expansion or contraction of the second lateral area <NUM> of the housing <NUM> when the first and second sets of screw members 14a-14b and 16a-16b are rotated independently to different positions on the first and second step tracking runs <NUM> and <NUM>.

The positions of the plurality of individual riser members <NUM> on the inferior shell member <NUM> may arrange to offset from the positions of the plurality of individual riser members <NUM> on the superior shell member <NUM> so that the plurality of individual riser members <NUM> of the inferior shell member <NUM> may intermesh the plurality of individual riser members <NUM> of the superior shell member <NUM> when the housing <NUM> is in a contraction configuration.

The first and second pairs of the screw members 14a-14b and 16a-16b may each have a tapered configuration and comprise a helical thread. The first pair of screw members 14a-14b may be arranged or disposed such that the directional orientation of the helical thread of the first screw member 14a of the first pair is opposite to the directional orientation of the second screw member 14b of the first pair so that the first and second screw members 14a-14b of the first pair move in an opposite direction in the first step tracking run <NUM> relative to each other upon rotation of the first drive shaft <NUM>. Similarly, the second pair of screw members 16a-16b may be arranged or disposed such that the directional orientation of the helical thread of the first screw member 16a of the second pair is opposite to the directional orientation of the helical thread of the second screw member 16b of the second pair so that the first and second screw members 16a-16b of the second pair move in an opposite direction in the second step tracking run <NUM> relative to each other upon rotation of the second drive shaft <NUM>.

By way of example, the first and second pairs of screw members 14a-14b, 16a-16b may be arranged such that when the first drive shaft <NUM> is rotated in a first direction, e.g. clockwise, the first pair of screw members 14a-14b move distally from the central portion <NUM> respectively along the first step tracking run <NUM>, and when the second drive shaft <NUM> is rotated in a second direction opposite to the first direction, e.g. counterclockwise, the second pair of screw members 16a-16b move distally from the central portion <NUM> respectively along the second step tracking run <NUM>. Alternatively, the first and second pairs of screw members 14a-14b, 16a-16b may be arranged such that when the first drive shaft <NUM> is rotated in a first direction the first pair of screw members 14a, 14b move distally from the central portion <NUM> respectively along the first step tracking run <NUM>, and when the second drive shaft <NUM> is rotated in a second direction same as the first direction the second pair of screw members 16a-16b move distally from the central portion <NUM> respectively along the second step tracking run <NUM>.

The first and second drive shafts <NUM>, <NUM> may each include features at their end portions for connecting with an operation instrument and for receiving and engaging a driver in the operation instrument. By way of example, the end portion of each of the first and second drive shafts <NUM>, <NUM> may be provided with an external thread <NUM> for connecting with an operation instrument, and an internal thread <NUM> for receiving and engaging with a driver in the operation instrument (<FIG>).

The dual-axis adjustable interbody fusion device <NUM> may include one or more extension springs <NUM>, <NUM> coupling the inferior and superior shell members <NUM>, <NUM>. The extension springs <NUM>, <NUM> can assure that the entire device stays together. Extreme coronal or sagittal imbalances may exist in patients, which may apply uneven distribution of forces on the interbody fusion device when implanted in the patients. Uneven distribution of forces on the internal mechanism may cause disassociation of the fusion device. The extension spring <NUM>, <NUM> may also work to keep an opposing force on the fusion. The mechanisms inside the fusion device may undergo expansion and/or lordotic adjustment once pressure is applied to the superior and inferior shell members of the device. An equal and opposite force may be needed for the mechanism to move efficiently and correctly. The extension springs <NUM>, <NUM> may create an initial tension against the mechanism, allowing it to expand and/or adjust lordotically when, for example, the patient's vertebral bodies have not made contact with the device.

The interbody fusion device <NUM> may include one or more thrust bearing <NUM> configured to limit unwanted axial and/or lateral movement of the drive shafts <NUM>, <NUM> while allowing the drive shafts <NUM>, <NUM> to rotate about their longitudinal axes. The thrust bearing <NUM> may be designed to have a ramp-like geometry <NUM> (<FIG>) allowing an instrument carrying a bone graft material to be guided into the device housing <NUM>. The ramp-like geometry may also allow for insertion of a fixation plate into the interbody fusion device for stabilizing and preventing migration of the interbody fusion device placed in adjacent vertebrae, to be described in greater detail below.

The inferior and superior shell members <NUM>, <NUM> of the housing <NUM> may include one or more openings or windows for accepting bone graft material or allowing bone to pass as fusion occurs. Suitable bone graft materials include but are not limited to autograft and/or allogenic bone graft materials comprising e.g. cancellous and/or corticocancellous bone graft. Bone graft materials can be packed into the interbody fusion device <NUM> before it is placed in between the vertebral bodies and/or added after the interbody fusion device <NUM> is expanded and/or lordotically adjusted to a proper configuration between the vertebral bodies. The sides or edges of the inferior and superior shell members <NUM>, <NUM> may include chamfered or rounded portions to facilitate insertion of the interbody fusion device into the patient's anatomy. The surfaces of the inferior and superior shell members <NUM>, <NUM> may include various features such as serrations, teeth, recesses, dents, etc. to help prevent migration of the device or provide better hold.

The interbody fusion device <NUM> or a part of the interbody fusion device <NUM> can be constructed from a material comprising metal such as titanium, tantalum, stainless steel, any other biocompatible metal, or alloy. The interbody fusion device <NUM> or a part of the interbody fusion device <NUM> can also be constructed from a polymeric material such as poly-ether-ether-ketone (PEEK), poly-ether-ketone-ketone (PEKK), poly-ether-ketone (PEK), and so on.

The interbody fusion device <NUM> can be in any size suitable for spinal fusion procedures. By way of example, the distance from the proximal end to the distal end of the device along the direction of the drive shaft <NUM>, <NUM> ("length") may range from <NUM> to <NUM> millimeters (mm). The distance from one lateral side of the device to the opposite lateral side ("width") may range from <NUM> to <NUM>. The device may be manufactured in numerous offerings with different lengths and widths in various increments, for example, <NUM> increments in width and <NUM> increments in length. The distance from the inferior shell member surface to the superior shell member surface of the interbody fusion device in a fully contracted configuration ("base height") may range from <NUM> to <NUM>. The dual-axis driving mechanisms according to embodiments of the disclosure can provide a continuous expansion in height adjustment e.g. ranging from <NUM> to <NUM> when operated simultaneously together, or e.g. ranging from <NUM>-<NUM> when operated independently of one another. The dual-axis driving mechanisms according to embodiments of the disclosure can provide a continuous angulation between the inferior and superior shell member surfaces ("lordosis") ranging from <NUM>-<NUM> degrees. It should be noted that the above specific dimensions are provided for thorough understanding of various aspects of the disclosure but are not intended to limit the scope of the claims.

With reference to <FIG>, embodiments of a dual-axis adjustable interbody fusion device with modular fixation or an apparatus <NUM> according to the disclosure will now be described. The use of one or more modular fixation plates allows for attachment of a fixation assembly to an interbody fusion device in situ following adjustment of the interbody fusion device to a desired configuration in the adjacent vertebrae, and provides stabilization and prevents migration of the interbody fusion device.

As shown in <FIG>, the apparatus <NUM> in general comprises an interbody fusion device <NUM> and a fixation assembly <NUM> including one or more modular fixation plates <NUM>, <NUM> and spinal anchor components <NUM> and <NUM>. The interbody fusion device <NUM> may be the same as, or similar to, the example dual-axis interbody fusion device <NUM> described above in conjunction with <FIG>. Alternatively, the interbody fusion device <NUM> can be any suitable dual-axis adjustable interbody fusion devices available from various manufacturers, which can be further adapted or modified for use with the fixation assembly <NUM>.

The fixation assembly <NUM> comprises at least a first or inferior fixation plate <NUM> and at least a first spinal anchor component or fastener <NUM>. Additionally, or alternatively, the fixation assembly <NUM> comprises a second or superior fixation plate <NUM> and a second spinal anchor component or fastener <NUM>. As used herein, the term "fixation plate" includes reference to a plate member or a plate assembly comprising a plate member and other parts or mechanisms assembled to the plate member. According to embodiments of the disclosure, the inferior fixation plate <NUM> is modular and configured to be attachable to the interbody fusion device <NUM>. As used herein, the term "modular" refers to an embodiment of a fixation plate constructed as a unit and capable of being assembled to an interbody fusion device prior to or following implantation of the interbody fusion device. A modular fixation plate in a fixation assembly may be replaced by another modular fixation plate of a structure same as that of the one being replaced. The inferior fixation plate <NUM> may be provided with an aperture <NUM> configured for insertion of the first fastener <NUM> therethrough to a first or inferior vertebral body. Likewise, according to certain embodiments of the disclosure, the superior fixation plate <NUM> is modular and configured to be attachable to the interbody fusion device <NUM>. The superior fixation plate <NUM> can be provided with an aperture <NUM> configured for insertion of the second fastener <NUM> therethrough to a second or superior vertebral body. Example fasteners or anchor components suitable for the first and/or second fasteners <NUM>, <NUM> include but are not limited to spinal expansion head screws, spinal locking screws, spinal self-locking screws, spinal shaft screws, spinal nails, spinal barbs, spinal hooks, or other threaded or non-threaded members which can be anchored to a vertebral body. In an assembled view shown in <FIG>, the modular inferior fixation plate <NUM> and the superior fixation plate <NUM> are attached to the interbody fusion device <NUM> with the first and second fasteners <NUM>, <NUM> being inserted through the apertures in the inferior and superior fixation plates <NUM>, <NUM>. It should be noted that in use, the modular inferior and superior fixation plates <NUM>, <NUM> can be attached to the interbody fusion device <NUM> in situ, or after the interbody fusion device <NUM> is placed between adjacent vertebral bodies and adjusted to a desired configuration. The modular inferior and superior fixation plates <NUM>, <NUM> may also be attached to the interbody fusion device <NUM> prior to implantation of the interbody fusion device if desired. <FIG>, which will be described in greater detail below, show that a modular superior fixation plate <NUM> and a modular inferior fixation plate <NUM> are attached to an interbody fusion device <NUM> with an operation instrument <NUM> after the interbody fusion device <NUM> has been placed, expanded, and/or lordotically adjusted to a proper configuration between adjacent vertebrae.

With reference to <FIG>, the modular inferior fixation plate <NUM> can be configured to be attachable to the interbody fusion device <NUM> serving to stabilize and prevent migration of the interbody fusion device <NUM> in adjacent vertebrae. According to certain embodiments of the disclosure, the modular inferior fixation plate <NUM> may be provided with geometry features configured for attachment to the interbody fusion device <NUM> to prevent unwanted rotation of a drive shaft e.g. the posterior drive shaft <NUM> of the interbody fusion device <NUM>. For instance, the inferior fixation plate <NUM> may include a male geometry <NUM> (<FIG>) configured to be inserted into the female geometry <NUM> in the end portion of the posterior drive shaft <NUM> of the interbody fusion device <NUM>. By way of example, the male geometry <NUM> in the inferior fixation plate <NUM> may have a male hexalobe feature which can be tightly mated into a female hexalobe feature <NUM> in the end portion of the posterior drive shaft <NUM> to prevent unwanted rotation of the drive shaft. A circular groove <NUM> around the male geometry <NUM> may be provided to accommodate the end portion of the posterior drive shaft <NUM>. <FIG> and 6A-6D, which will be described in greater detail below, show the attachment of the inferior fixation plate <NUM> to the interbody fusion device <NUM>, where the male geometry <NUM> in the inferior fixation plate <NUM> is tightly mated into the female geometry <NUM> in the end portion of the posterior drive shaft <NUM>.

With reference to <FIG>, the inferior fixation plate <NUM> may be provided with geometry features allowing for pivoting of the inferior fixation plate <NUM> relative to the interbody fusion device <NUM> before the male geometry <NUM> in the inferior fixation plate <NUM> is mated into the female geometry <NUM> in the end portion of the posterior drive shaft <NUM> of the interbody fusion device <NUM>. For instance, the inferior fixation plate <NUM> may include a channel geometry <NUM> configured to accommodate e.g. the end portion of the anterior drive shaft <NUM> of the interbody fusion device <NUM>. The channel geometry <NUM> allows the inferior fixation plate <NUM> to "pivot" about the posterior drive shaft <NUM> without interfering with the anterior drive shaft <NUM>, by accommodating the end portion of the anterior drive shaft <NUM> in the channel geometry <NUM>. The ability for the inferior fixation plate <NUM> to pivot allows the position of the aperture <NUM> in the inferior fixation plate <NUM> to be adjusted e.g. according to the expanded and/or lordotically adjusted configuration of the interbody fusion device <NUM>, thereby providing an optimal position of the aperture relative to the vertebral body for the fastener. <FIG> shows the channel geometry <NUM> in the inferior fixation plate <NUM> as attached to the interbody fusion device <NUM>. The channel geometry <NUM> extends from a first end 129a to a second end 129b, allowing the inferior fixation plate <NUM> to "pivot" about the posterior drive shaft <NUM> by accommodating the end portion of the anterior drive shaft <NUM> in the channel <NUM> e.g. at the first end 129a when the interbody fusion device <NUM> is in an expanded but a non-lordotically adjusted configuration (<FIG>), or at the second end 129b when the interbody fusion device <NUM> is in a hyperlordotically adjusted configuration (<FIG>), or at any position therebetween when the interbody fusion device <NUM> is in a configuration between a non-lordotically adjusted configuration and hyperlordotically adjusted configuration.

With reference to <FIG>, the inferior fixation plate <NUM> may include an attachment-lock mechanism <NUM> engageable to lock the interbody fusion device <NUM> to secure the attachment of the the inferior fixation plate <NUM> to the interbody fusion device <NUM>. According to certain embodiment of the disclosure, the attachment-lock mechanism <NUM> may include a lock housing 130a, a rod 130b, a compression spring 130c loaded on the rod 130b and retained in the lock housing 130a, and a latch 130d coupled to a distal end portion of the rod 130b. The proximal end portion of the rod 130b may have features for receiving a driving tool to actuate the attachment-lock mechanism <NUM>. For example, the proximal end portion of the rod 130b may be provided with a female hexalobe feature for receiving a torx driver. In use, the user may press the rod 130b with a driver to displace the latch 130d coupled to the distal end portion of the rod 130b to allow the latch 130d to rotate and hook to a component in the interbody fusion device <NUM>. The compression spring 130c loaded on the rod 130b apply a force to the latch 130d, and upon release of the driver, the latch 130d tightens the attachment of the inferior fixation plate <NUM> to the interbody fusion device <NUM>, or locks the interbody fusion device <NUM> to the inferior fixation plate <NUM>. The lock housing 130a may be provided with features such as a thread configured for connecting with an operation instrument. <FIG> show the latch 130d of the attachment-lock mechanism <NUM> in an unlocked state. <FIG> show the latch 130d of the attachment-lock mechanism <NUM> in a locked state wherein the latch 130d interferes or hold in place the external thread in the end portion of the posterior drive shaft <NUM>, preventing the posterior drive shaft <NUM> from unwanted rotation.

With reference still to <FIG>, the inferior fixation plate <NUM> may include a fastener-lock mechanism <NUM> configured to prevent the first fastener <NUM> from backing out of the aperture <NUM> after being fastened. According to certain embodiments of the disclosure, the fastener-lock mechanism <NUM> may comprise a lock component 132a received in a recess 132b adjacent to the fastener aperture <NUM> in the inferior fixation plate <NUM>, a compression spring 132c loaded on a part of the lock component 132a, and a retainer 132d connected to a part of the lock component 132a. The retainer 132d retains the lock component 132a in the recess 132b via a compression spring loaded on the lock component 132a and is slidable with the lock rod 132a relative to the inferior fixation plate <NUM>. The fastener-lock mechanism <NUM> has a locked state when the compression spring 132c is in a free or extended state allowing the lock component 132a to extend partially over the aperture <NUM> in the inferior fixation plate <NUM>, and an unlocked state when the compression spring 132c is in a compressed state forcing the lock component 132a away from the aperture <NUM> in the inferior fixation plate <NUM>. In use, when a fastener <NUM> is inserted into the aperture <NUM>, the spring-loaded lock component 132a is forced away from the aperture <NUM>, allowing the the fastener <NUM> to be driven e.g. screwed into a vertebral body. Once the fastener <NUM> is driven all the way and the head of the fastener <NUM> is received in the countersink of the aperture <NUM> and flushed with or below the surface of the fixation plate <NUM>, the spring-loaded lock component 132a springs back at least partially over the fastener head, preventing the fastener <NUM> from backing out. The fastener-lock mechanism <NUM> allows for "zero step" locking because the surgeon does not need any extra instrument or step to engage the fastener-lock mechanism <NUM> in order to cover the fastener head to keep them from backing out. With greater clarity, <FIG> show an example fastener-lock mechanism <NUM> in a fixation plate <NUM> to be described below. The fastener-lock mechanism <NUM> in the inferior fixation plate <NUM> can be the same as or similar to the fastener-lock mechanism <NUM> in a fixation plate <NUM> shown in <FIG>. Alternatively, the fastener-lock mechanism <NUM> in the inferior fixation plate <NUM> can be the same as or similar to the fastener-lock mechanism <NUM> to be described in conjunction with <FIG>.

With reference now to <FIG>, the modular superior fixation plate <NUM> can be configured to be attachable to the interbody fusion device <NUM> serving to stabilize and prevent migration of the interbody fusion device placed <NUM> in adjacent vertebrae. According to certain embodiments of the disclosure, the modular superior fixation plate <NUM> may include a protruding portion <NUM> configured to be insertable into the interbody fusion device <NUM>. The protruding portion <NUM> may have a geometry configured to tightly mate with an internal component(s) of the interbody fusion device <NUM> to restrict unwanted movement of the interbody fusion device <NUM>. By way of example, the protruding portion <NUM> may have a geometry generally in the shape of a rectangular prism, which can be placed tightly in or between a channel in the inner surface of the superior shell member <NUM>. As such, translational movement of the interbody fusion device <NUM> relative to the superior fixation plate <NUM> in lateral, posterior, and/or anterior direction can be prohibited or minimized. The protruding portion <NUM> may also in any other suitable shapes or forms. <FIG> show the superior fixation plate <NUM> inserted in the interbody fusion device <NUM>.

With reference to <FIG>, the superior fixation plate <NUM> may include an attachment-lock mechanism <NUM> engageable to secure the attachment of the superior fixation plate <NUM> to the interbody fusion device <NUM> or lock the interbody fusion device <NUM>. The attachment-lock mechanism <NUM> of the superior fixation plate <NUM> is the same as or similar to the attachment-lock mechanism <NUM> of the inferior fixation plate <NUM> in many aspects. For completeness of description, the attachment-lock mechanism <NUM> of the superior fixation plate <NUM> may include a lock housing 150a, a rod 150b, a compression spring 150c loaded on the rod 150b and retained in the lock housing 150a, and a latch 150d coupled to a distal end portion of the rod 150b. <FIG> shows the attachment-lock mechanism <NUM> in an unlocked state, with the superior fixation plate <NUM> being inserted in the interbody fusion device <NUM>. <FIG> shows the attachment-lock mechanism <NUM> in a locked state, with the superior fixation plate <NUM> being inserted in the interbody fusion device <NUM> and locked.

With reference still to <FIG>, the superior fixation plate <NUM> may further include a fastener-lock mechanism <NUM> configured to prohibit the second fastener <NUM> from backing out of the aperture <NUM> in the superior fixation plate <NUM>. The faster-lock mechanism <NUM> of the superior fixation plate <NUM> is the same as or similar to the fastener-lock mechanism <NUM> of the inferior fixation plate <NUM> in many aspects and its detail description is omitted herein.

Returning to <FIG>, the modular inferior and superior fixation plates <NUM>, <NUM> may be shaped and/or sized or configured to allow the two fixation plates to at least partially intermesh when being attached to the interbody fusion device <NUM>. By way of example, the inferior fixation plate <NUM> may comprise an edge portion having a concave profile <NUM>, the superior fixation plate <NUM> may comprise an edge portion having a convex profile <NUM>. The concave edge portion <NUM> of the inferior fixation plate <NUM> and the convex edge portion <NUM> of the superior fixation plate <NUM> allows for at least partial intermeshing, thereby allowing attachment of the inferior fixation plate <NUM> and the superior fixation plate <NUM> to the interbody fusion device <NUM> when the interbody fusion device <NUM> is in a contracted configuration or an expanded configuration of a lesser degree. The rounded or scalloped profile of the concave edge portion <NUM> of the inferior fixation plate <NUM> and the convex edge portion <NUM> of the superior fixation plate <NUM> also allow attachment of the inferior and superior fixation plates <NUM>, <NUM> to the interbody fusion device <NUM> when the interbody fusion device <NUM> is in a lordotically or hyperlordotically adjusted configuration (e.g. <NUM> to <NUM> degrees of lordosis). <FIG> show attachment of the inferior and superior fixation plates <NUM>, <NUM> and fasteners <NUM>, <NUM> to an interbody fusion device <NUM> in a contracted, a fully expanded, and a lordotically adjusted configuration respectively. For ease of description and illustration, the dimensions set forth below refer to embodiments where the dual-axis adjustable interbody fusion device <NUM> is placed between adjacent vertebrae via a lateral lumbar interbody fusion (LLIF) procedure, expanded and/or lordotically adjusted by operating the two driving mechanisms along the anterior and/or posterior side of the patient respectively to achieve a configuration suitable for a sagittal balance for the patient. It will be appreciated by one of ordinary skill in the art that the interbody fusion device can be placed via an anterior lumbar interbody fusion (ALIF) or posterior lumbar interbody fusion (PLIF) procedure, and is expanded or lordotically adjusted by operating the driving mechanisms along the lateral and/or contra-lateral side respectively to achieve a desired coronal balance or correct coronal imbalance for the patient.

<FIG> shows an embodiment where the interbody fusion device <NUM> is contracted to a configuration having a height at the anterior side ("anterior height") of <NUM>, a height at the posterior height ("posterior height") of <NUM>, and an angle between the superior and inferior shell members ("lordosis") of <NUM> degree. The concave and convex profile of the edge portions allow the modular inferior and superior fixation plates <NUM>, <NUM> to be inserted and attached to the interbody fusion device <NUM> respectively. <FIG> shows an embodiment where the interbody fusion device <NUM> is in a fully expanded configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. The modular inferior and superior fixation plates <NUM>, <NUM> attached to the interbody fusion device can stabilize and prevents the interbody fusion device <NUM> in a fully expanded configuration from migration. <FIG> shows an embodiment where the interbody fusion device <NUM> is in a hyperlordotically adjusted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. The modular inferior and superior fixation plates <NUM>, <NUM> attached to the interbody fusion device <NUM> can stabilize and prevent the interbody fusion device in a hyperlordotically adjusted configuration from migration. In comparison of <FIG> with <FIG>, the channel geometry in the inferior fixation plate <NUM> allows the inferior fixation plate <NUM> to be "pivoted" around the posterior drive shaft <NUM> before final attachment (notice the different position of the anterior drive shaft <NUM> in the channel geometry in the inferior fixation plate <NUM>), thereby allowing angulation of the inferior fixation plate <NUM> relative to the interbody fusion device <NUM>, providing an optimal position of the aperture in the inferior fixation plate <NUM> and thus an optimal fastener trajectory. Further, the apertures in the inferior and superior fixation plates <NUM>, <NUM> can be configured or machined such that the axis of the apertures can angle from the inferior and superior fixation plates respectively, as will be described in more detail in conjunction with <FIG>. The angled apertures in the inferior and superior fixation plates <NUM>, <NUM> and selections of fasteners (e.g. rounded head portion of the fasteners) allow the fasteners <NUM>, <NUM> to have variable trajectories e.g. from <NUM> to <NUM> degrees in the caudal and cephalad directions, as shown in <FIG> respectively. It should be noted that the specific dimensions and degrees provided above are for thorough understanding of various embodiments of the disclosure but not intended to limit the scope of the claims.

The dual-axis adjustable interbody fusion device with modular fixation or apparatus <NUM> can be used in treatment of various spinal diseases, including but not limited to degenerative disc disease (DDD), spondylolisthesis, retrolisthesis (Grade <NUM>), and so on. As shown in <FIG>, in use the modular inferior and superior fixation plates <NUM>, <NUM> can be inserted and attached to an interbody fusion device <NUM> in situ. For instance, an interbody fusion device <NUM> in a contracted configuration can be first inserted and placed between adjacent vertebrae <NUM>, <NUM> using an operation instrument <NUM> via a suitable surgical procedure. Suitable surgical procedure for placing the interbody fusion device <NUM> include a lateral lumbar interbody fusion (LLIF) procedure, an anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF) procedure, and any other suitable surgical procedures performed in the lumbar or other regions of the spinal column. Various suitable operation instruments are described in <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Fusion Systems" and <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Fusion Systems". The interbody fusion device <NUM> can be expanded and/or lordotically adjusted using the operation instrument <NUM>, forming a suitable configuration between the adjacent vertebrae <NUM>, <NUM>. By way of example, the operation instrument <NUM> can connect the interbody fusion device <NUM> via the external threads <NUM> on the end portions of the posterior and anterior drive shafts <NUM>, <NUM>, and expand or lordotically adjust the interbody fusion device <NUM> by engaging the female features <NUM> in the end portions of the posterior and anterior drive shafts <NUM>, <NUM> (<FIG>).

Then, a modular superior fixation plate <NUM> can be introduced to the target area and attached to the interbody fusion device <NUM> through the same surgical approach for placing the interbody fusion device <NUM>. According to embodiments of the disclosure, operation instrument <NUM> used for placing and operating the interbody fusion device <NUM> can be used for inserting and attaching the modular superior fixation plate <NUM>. For instance, the surgeon can connect the superior fixation plate <NUM> with the operation instrument <NUM> via the thread provided at the lock housing 150a of attachment-lock mechanism <NUM> (<FIG>), introduce the superior fixation plate <NUM> to the target area through the same surgical approach, insert the protruding portion of the superior fixation plate <NUM> into the interbody fusion device <NUM>. The interbody fusion device <NUM> can be locked to superior fixation plate <NUM> using the operation instrument <NUM> by actuating the attachment-lock mechanism <NUM>.

After or before inserting and attaching the modular superior fixation plate <NUM>, a modular inferior fixation plate <NUM> can be introduced to the target area and attached to the interbody fusion device <NUM> using the same operation instrument <NUM> through the same surgical approach for placing the interbody fusion device <NUM>. For instance, the surgeon can connect the inferior fixation plate <NUM> with the operation instrument <NUM> via the thread provided at the lock housing 130a of lock-attachment mechanism <NUM> (<FIG>), introduce the inferior fixation plate <NUM> to the target area through the same surgical approach, insert the male geometry <NUM> in the inferior fixation plate <NUM> into the female geometry <NUM> in the end portion of the posterior drive shaft <NUM>. Optionally, before final engagement of the male geometry <NUM> of inferior fixation plate <NUM> with the female geometry <NUM> of the posterior drive shaft <NUM>, the inferior fixation plate <NUM> can be pivoted about the posterior drive shaft <NUM> to adjust or provide an optimal position of the aperture <NUM> in the inferior fixation plate <NUM> for an optima fastener trajectory. The the interbody fusion device <NUM> can be then further locked to the inferior fixation plate <NUM> using the operation instrument <NUM> by actuating the attachment-lock mechanism <NUM>.

Fasteners <NUM>, <NUM> such as spinal bone screws can be then inserted through the apertures in the superior and inferior fixation plates <NUM>, <NUM> and screwed into the first vertebral body <NUM> and the second vertebral body <NUM> respectively. Once the fasteners <NUM>, <NUM> are driven all the way and the heads of the fasteners are received in the countersinks of the apertures in the fixation plates, the fastener-lock mechanisms in the superior and inferior fixation plates <NUM>, <NUM> automatically actuate, prohibiting the fasteners <NUM>, <NUM> from backing out. The interbody fusion device <NUM> can be stabilized and prevented from migrating in the vertebral bodies <NUM>, <NUM>, as shown in <FIG>.

Embodiments of a dual-axis adjustable interbody fusion device with modular fixation or apparatus <NUM> are described in conjunction with <FIG>. Beneficially, the interbody fusion device with modular fixation <NUM> can provide stabilization and prevent migration of the interbody fusion device in highly expanded and/or hyperlordotically adjusted configurations to safely promote fusion between adjacent vertebral bodies. The modular superior and inferior fixation plates allow for in-situ attachment of either or both plates to an interbody fusion device of any suitable size and configuration following adjustments of the interbody fusion device, as well as the option for attachment to the interbody fusion device prior to implantation. The modular fixation plates are insertable and attachable to an interbody fusion device via a single surgical approach and patient position, thereby minimizing disruption to the patient anatomy. The modular design also gives the surgeon an option of using the fixation assembly during surgery or leave off if desired following an added interbody configuration. The modular inferior fixation plate <NUM> and superior fixation plate <NUM> follow the anterior and posterior angulation of the inferior shell member <NUM> and the superior shell member <NUM> of the interbody fusion device <NUM> from <NUM>-<NUM> degrees respectively, or <NUM>-<NUM> degrees measured from the center of the modular inferior fixation plate to the center of the modular superior fixation plate, thereby allowing for desired screw trajectory and placement into cortical bones.

The interbody fusion device with fixation <NUM> allows the surgeon to set the interbody fusion device in fine configurations, especially with any height in highly expanded configurations and at any angle in hyperlordotically adjusted configurations between <NUM>°-<NUM>° for any patient, without further disruption to the patient anatomy caused by additional surgery needed for an independent screw and plate system. While kyphotic (negative lordosis) adjustments may not be desirable for the lumbosacral segment of the spine, the interbody fusion device with fixation <NUM> has the ability to adjust to kyphotic and hyperkyphotic angle configurations. Therefore, the interbody fusion device with fixation <NUM> can provide complete personalization for the patient, allowing the surgeon to adjust the interbody fusion device to any unique height and/or angle (e.g. <NUM>°) needed for the patient's spinal balance profile. Conventional techniques may allow for an interbody fusion device to be set at only a few different lordotic configurations such as <NUM>°, <NUM>°, <NUM>°, and separate screw and plate systems have to be used through an additional surgery to stabilize the fusion device in a lordotic configuration.

The interbody fusion device with fixation <NUM> can also increase surgical efficiency. Conventionally, surgeons have to perform impactful trialing, or sizing of the implant to determine the size of an implant needed for a specific patient. According to embodiments of the disclosure, the interbody fusion device can start at a smaller contracted height and then increase in height in situ. This allows for streamlining or drastically reducing the trialing process, which can in turn decrease the barbaric and rough impact associated with the trialing process. Modular fixation plates may be used for hyperlordotic configurations, reducing the need for placing an extra fixation plate and set of bone screws independent of the interbody fusion device. The use of modular fixation plates causes less disruption to the patient anatomy. Once the surgeon adjusts the interbody fusion device to the patient's unique spinal profile e.g. sagittal balance profile, the intervertebral disc height and lordosis, modular fixation plates can be inserted through the same surgical approach and attached to the fusion device to secure the fusion device to the vertebral bodies without the need for additional surgical approach to place a separate plate and screw fixation system to the spine anteriorly.

The modular design of the fixation assembly also provides benefits pertaining to manufacturing and hospital administration. It can reduce inventory. A single set of inferior and superior fixation plates can work with a dual-axis interbody fusion device of any size and configuration of a making, thereby drastically reducing manufacturing and operational costs. The use of a single set of inferior and superior fixation plates with dual-axis interbody fusion devices of any size and configuration simplifies the need of tracking, by tracking only one set of fixation plates in the hospital or the operating room.

With reference to <FIG>, an example dual-axis adjustable spinal system <NUM> according to embodiments of the disclosure will now be described. The use of a single fixation plate in the spinal system allows for attachment of a fixation assembly to the interbody fusion device in situ following adjustment of the interbody fusion device to a desired configuration in the adjacent vertebrae. The single fixation plate can be constructed from a material having sufficient strength such as titanium, stainless steel or other metal or metal alloy to provide orthotic support or supplemental fixation in addition to providing stabilization and preventing migration of the interbody fusion device. As used herein, the term "supplemental fixation" refers to an embodiment of the single fixation plate serving as an orthotic capable of holding adjacent vertebrae in place or immobilizing movement of adjacent vertebrae until arthrodesis (bony fusion) takes place.

As shown in <FIG>, the spinal system <NUM> comprises an interbody fusion device <NUM> and a fixation assembly <NUM>. The interbody fusion device <NUM> may be the same as or similar to the device <NUM> described above in conjunction with <FIG>. Alternatively, the interbody fusion device <NUM> can be any suitable dual-axis adjustable interbody fusion devices available from various manufacturers, which can be further adapted or modified for use with the fixation assembly <NUM>.

The fixation assembly <NUM> comprises a single fixation plate <NUM>, at least a first fastener <NUM> and a second fastener <NUM>. The single fixation plate <NUM> is configured to be attachable to the interbody fusion device <NUM>. The single fixation plate <NUM> is provided with at least a first aperture <NUM> configured for insertion of the first fastener <NUM> therethrough to secure to a first vertebral body, and a second aperture <NUM> configured for insertion of the second fastener therethrough to secure to a second vertebral body. As used herein, the term "single" refers to one fixation plate provided with at least two apertures for insertion of at least two fasteners capable of stabilizing an interbody fusion device between two adjacent vertebral bodies. However, the use of the term "single" does not exclude other parts assembled to the fixation plate for performing other functions such as locking etc. As used herein, the term "fixation plate" includes reference to a plate member or a plate assembly comprising a plate member and other parts or mechanisms assembled to the plate member. While two fasteners and two apertures in the single fixation plate are shown for illustration purpose, other embodiments may include more than two fasteners and more than two apertures in the fixation plate. Further, <FIG> show assembled views of the spinal system <NUM> where the single fixation plate <NUM> is attached to the interbody fusion device <NUM>, with the first and second fasteners <NUM>, <NUM> being inserted through the apertures in the fixation plate. It should be noted that in use, the single fixation plate <NUM> can be attached to the interbody fusion device <NUM> in situ, or when the interbody fusion device <NUM> has been inserted in the patient and placed between adjacent vertebral bodies. The single fixation plate <NUM> may also be attached to the interbody fusion device <NUM> prior to implantation if desired, assuming the interbody fusion device is adjusted prior to implantation. 18A, which will be described in greater detail below, shows that a single fixation plate <NUM> is inserted in the patient and attached to an interbody fusion device with an operation instrument after the interbody fusion device has been placed, expanded, and/or lordotically adjusted to a proper configuration between adjacent vertebrae.

With reference to <FIG>, the single fixation plate <NUM> can be configured to be attachable to the interbody fusion device <NUM>. For instance, the single fixation plate <NUM> may be provided with geometry features configured for attachment to the interbody fusion device <NUM> and preventing unwanted rotation of the drive shafts <NUM> and <NUM> of the interbody fusion device <NUM>. According to certain embodiments of the disclosure, the single fixation plate <NUM> in the back side may include a first male geometry <NUM> and a second male geometry <NUM> spaced apart to each other (<FIG>). The first and second male geometries <NUM> and <NUM> may be configured to be inserted into the female geometries <NUM> in the end portions of the first (e.g. posterior) and second (e.g. anterior) drive shafts <NUM> and <NUM> of the interbody fusion device <NUM> respectively. By way of example, the first and second male geometries <NUM>, <NUM> may have male hexalobe features which can be tightly mated into the female hexalobe features <NUM> in the end portions of the first and second drive shafts <NUM>, <NUM> to prevent unwanted rotation of the first and second drive shafts <NUM>, <NUM>. The first and second male geometries may have other mating features and the above hexalobe example is provided for illustration purpose. Surrounding each of the first and second male geometries <NUM>, <NUM>, circular grooves <NUM>, <NUM> can be provided to receive or accommodate the end portions of the first and second drive shafts <NUM> and <NUM> of the interbody fusion device <NUM> when the single fixation plate <NUM> is attached to the interbody fusion device <NUM>. <FIG> shows attachment of the single fixation plate <NUM> to the interbody fusion device <NUM>, where the first and second male geometries <NUM> and <NUM> in the single fixation plate <NUM> are received in the female geometries <NUM> in the end portions of the first and second drive shafts <NUM>, <NUM> respectively, and the end portions of the first and second drive shafts <NUM> and <NUM> fit in the circular grooves in the single fixation plate <NUM>.

With reference to <FIG>, the single fixation plate <NUM> may alternatively or additionally include a protruding portion <NUM> configured to be insertable into the interbody fusion device <NUM> to stabilize and prevent migration of the interbody fusion device <NUM> placed between adjacent vertebrae. According to certain embodiments of the disclosure, the protruding portion <NUM> in the single fixation plate <NUM> may have a geometry configured to tightly mate with an internal component(s) of the interbody fusion device <NUM> to restrict unwanted movement of the interbody fusion device <NUM>. By way of example, the protruding portion <NUM> may have a geometry generally in the shape of a rectangular prism, which can be tightly inserted in a ramp-like geometry of the thrust bearing <NUM> (<FIG>) of the interbody fusion device <NUM>. As such, unwanted translational movement of the interbody fusion device <NUM> in any of lateral, posterior, and anterior directions can be prohibited or minimized. The protruding portion <NUM> may also in any other suitable shapes or forms such as a cube, semi-cylinder, or polygonal prism shape, etc. <FIG> show the protruding portion <NUM> of the single fixation plate <NUM> inserted in the interbody fusion device <NUM>, and an attachment-lock mechanism <NUM> in an unlocked state (<FIG>) and a locked state (<FIG>), to be described further below.

With reference to <FIG>, the single fixation plate <NUM> may include an attachment-lock mechanism <NUM> engageable to lock the interbody fusion device <NUM> or secure the attachment of the single fixation plate <NUM> to the interbody fusion device <NUM>. According to certain embodiment of the disclosure, the attachment-lock mechanism <NUM> may be the same as or similar to the attachment-lock mechanism <NUM> shown in <FIG> or the attachment-lock mechanism <NUM> shown in <FIG>. For completeness of description, the attachment-lock mechanism <NUM> in the single fixation plate <NUM> may include a lock housing 240a, a rod 240b, a compression spring 240c loaded on the rod 240b and retained in the lock housing 240a, and a latch 240d coupled to a distal end portion of the rod. The proximal end portion of the lock rod 240b may have features for receiving a driving tool to actuate the attachment-lock mechanism <NUM>. For example, the proximal end portion of the rod 240b may be provided with a female hexalobe feature for receiving a driver having a male hexalobe feature. In use, the user may press the rod 240b with a driver to displace the latch 240d coupled to the distal end portion of the rod 240b to allow the latch to rotate and hook to a component in the interbody fusion device <NUM>. The compression spring 240c loaded on the rod 240b apply a force to the latch 240d, and upon release of the driver, the latch 240d tightens the attachment of the inferior fixation plate <NUM> to the interbody fusion device <NUM>, or locks the interbody fusion device <NUM> to the single fixation plate <NUM>. The housing 240a of the attachment-lock mechanism <NUM> may be provided with features such as a thread configured for connecting with an operation instrument for actuating the attachment-lock mechanism <NUM> and/or placing the single fixation plate in the patient anatomy. <FIG> shows the attachment-lock mechanism <NUM> in an unlocked state where the latch 240d is in an unlocked position. <FIG> shows the attachment-lock mechanism <NUM> in a locked state where the latch 240d is a locked position hooking to a component (e.g. the thrust bearing) of the interbody fusion device <NUM>.

With reference to <FIG>, the single fixation plate <NUM> may further include a first fastener-lock mechanism <NUM> and a second fastener-lock mechanism <NUM>. The first and second fastener-lock mechanisms in the single fixation plate <NUM> may be the same as or similar to the fastener-lock mechanism <NUM> shown in <FIG> or the fastener-lock mechanism <NUM> shown in 4A-4D. For completeness of description, the first fastener-lock mechanism <NUM> in the single fixation plate <NUM> may comprise a lock component 242a received in a recess 242b adjacent to the first aperture <NUM>, a compression spring 242c loaded on a part of the lock component 242a, and a retainer 242d connected to a part of the lock component 242a. The retainer 242d retains the lock component 242a in the recess 242b via a compression spring loaded on the lock component 242a and is slidable with the lock component 242a relative to the single fixation plate <NUM>, allowing the lock component 242a to extend over and/or retract from the aperture <NUM> when in use. The second fastener-lock mechanism <NUM> may be the same as or similar to the first fastener-lock mechanism <NUM>. Alternatively, the first and second fastener-lock mechanisms <NUM>, <NUM> are the same as or similar to the fastener-lock mechanisms <NUM> and <NUM> in the fixation plates <NUM> and <NUM> to be described in conjunction with <FIG>.

<FIG> depict some aspects of the first fastener-lock mechanism <NUM> in the single fixation plate <NUM> with greater clarity. The compressed state and the extended (free) state of the compression spring allows the spring-loaded lock component 242a to have an unlock/open position and a locked position respectively. In the extended or free state of the compression spring, the lock component 242a extends partially over the aperture <NUM> in the fixation plate <NUM>. When a fastener <NUM> is inserted into the aperture <NUM> by a driver, the spring-loaded lock component 242a is forced away from the aperture <NUM>, allowing the fastener <NUM> to be fastened e.g. screwed into a vertebral body. Once the fastener <NUM> is screwed all the way and the head of the fastener <NUM> is flushed with or below the surface of the fixation plate <NUM>, the spring-loaded lock component 242a springs back at least partially over the fastener head, preventing the fastener <NUM> from backing out. The fastener-lock mechanism <NUM> of the disclosure allows for "zero step" locking since the surgeon does not need any surgical instrument or step to engage the fastener-lock mechanism <NUM> in order to cover the fastener head to keep them from backing out e.g. unthreading from the vertebral body.

<FIG> shows that the first and second apertures <NUM> and <NUM> in the single fixation plate <NUM> may be angled. For example, the centerline <NUM> of the first aperture <NUM> may be angled from <NUM>-<NUM> degrees with respect to a reference plane such as a reference plane parallel with the surface of the fixation plate. Similarly, the centerline <NUM> of the second aperture <NUM> may be angled from <NUM>-<NUM> degrees with respect to a reference plane such as a reference plane parallel with the surface of the single fixation plate. An angled aperture allows for the fastener inserted therethrough to have an angled trajectory, providing optimal purchase for the fastener to the vertebral body. The first and second apertures <NUM>, <NUM> can be configured to allow the first and second fastener <NUM> and <NUM> to angle from <NUM>-<NUM> degrees e.g. in a caudal or cephalad direction respectively or in any other directions. The first and second apertures <NUM>, <NUM> may include a counterbore or countersink portion configured for receiving the head of the first and second fasteners. The head of the fasteners may have a spherical shape as shown <FIG> or any other suitable shapes such as tapered or cylindrical shape. Examples of fasteners include but are not limited to spinal expansion head screws, spinal locking screws, spinal self-locking screws, spinal shaft screws, spinal nails, spinal barbs, spinal hooks, and any other threaded or unthreaded fasteners.

<FIG> illustrate that the single fixation plate <NUM> can be attached to the interbody fusion device <NUM> in various configurations, including in a contracted configuration, a fully expanded configuration, and a lordotically or hyperlordotically adjusted configuration. While kyphotic (negative lordosis) adjustments may not be desirable for the lumbosacral segment of the spine, the interbody fusion device <NUM> can be connected with the single fixation plate assembly in kyphotic and hyperkyphotic angle configurations. By way of example where the interbody fusion device <NUM> is placed between adjacent vertebrae via a lateral surgical procedure, <FIG> shows that the single fixation plate <NUM> can be attached to the interbody fusion device <NUM> in a contracted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an example where the single fixation plate <NUM> is attached to the interbody fusion device <NUM> in a fully expanded configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an example where the single fixation plate <NUM> is attached to the interbody fusion device <NUM> in a hyperlordotically adjusted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. The angled first and second apertures in the single fixation plate <NUM> allow screw angulation up to <NUM> degrees in the caudal and cephalad directions respectively, as shown in <FIG>.

The dual-axis adjustable spinal system <NUM> can be used in treatment of various spinal diseases including but not limited to degenerative disc disease (DDD), spondylolisthesis, retrolisthesis, trauma, tumors, deformities, pseudoarthrosis, previous failed fusions, and so on. In use, as shown in <FIG>, the single fixation plate <NUM> can be inserted and attached to an interbody fusion device <NUM> in situ. For instance, an interbody fusion device <NUM> in a contracted configuration can be first inserted and placed between adjacent vertebrae <NUM>, <NUM> using an operation instrument <NUM> via a suitable surgical procedure. Suitable surgical procedure for introducing the interbody fusion device <NUM> in the patent anatomy include a lateral lumbar interbody fusion (LLIF) procedure, an anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF) procedure, and any other suitable surgical procedures performed in the lumbar or other regions of the spinal column. Various suitable operation instruments are described in <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Fusion Systems" and <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Systems". The interbody fusion device <NUM> can be expanded and/or lordotically adjusted using an operation instrument <NUM>, forming a suitable configuration between the adjacent vertebrae <NUM>, <NUM>. By way of example, the operation instrument <NUM> can connect the interbody fusion device <NUM> via the external threads <NUM> on the end portions of the posterior and anterior drive shafts <NUM>, <NUM>, and expand or lordotically adjust the interbody fusion device <NUM> by engaging the female features <NUM> in the end portions of the posterior and anterior drive shafts <NUM>, <NUM> (<FIG>). The interbody fusion device <NUM> can be expanded and/or lordotically adjusted to a configuration suitable for treating the patient.

Then, the single fixation plate <NUM> can be introduced to the target area, via the same surgical approach for inserting and placing the interbody fusion device <NUM>, and attached to the interbody fusion device <NUM>. According to embodiments of the disclosure, the operation instrument <NUM> used for placing and operating the interbody fusion device <NUM> can be used for inserting and attaching the single fixation plate <NUM>. By way of example, the surgeon can connect the single fixation plate <NUM> to the operation instrument <NUM> via the thread provided at the lock housing 240a of lock-attachment mechanism <NUM>, introduce the single fixation plate <NUM> to the target area via the same surgical approach, align the first and second male geometries <NUM>, <NUM> with the female geometries <NUM> in the end portions of the posterior and anterior drive shafts <NUM>, <NUM> of the interbody fusion device <NUM>, and insert the single fixation plate <NUM> to the interbody fusion device <NUM>. The interbody fusion device <NUM> can further be locked to the single fixation plate <NUM> using the operation instrument <NUM> by actuating the attachment-lock mechanism <NUM>.

Fasteners <NUM>, <NUM> such as bone screws can be then inserted through the apertures in the single fixation plate <NUM> and screwed into the first vertebral body <NUM> and the second vertebral body <NUM> respectively. Once the fasteners <NUM>, <NUM> are driven all the way and the heads of the fasteners <NUM>, <NUM> are received in the apertures in the single fixation plate <NUM>, the fastener-lock mechanisms <NUM>, <NUM> in the single fixation plates <NUM> automatically actuate to lock the fasteners <NUM> and <NUM> prohibiting them from backing out. The interbody fusion device <NUM> can be stabilized and prevented from migrating in the vertebral bodies <NUM>, <NUM>, as shown in <FIG>. In addition, the single fixation plate <NUM> can be constructed from a material having sufficient strength such as stainless steel or other metal or metal alloy to provide supplemental fixation holding the adjacent vertebrae <NUM> and <NUM> in place or immobilizing movement of adjacent vertebrae for promoting safe body fusion.

Embodiments of a dual-axis adjustable spinal system <NUM> comprising a single fixation plate are described in conjunction with <FIG>. Beneficially, the spinal system <NUM> can provide stabilization and promote fusion between adjacent vertebral bodies without further need of supplemental posterior fixation when treating degenerative disc disease, spondylolisthesis, retrolisthesis (Grade <NUM>), etc. The single fixation plate can be constructed with sufficient strength to provide orthotic support or supplemental fixation. The single fixation plate <NUM> is implantable and configurable to attach to an interbody fusion device via a single surgical approach and patient position, thereby minimizing disruption to the patient anatomy. The geometry such as the male geometries in the single fixation plate can act as secondary safety lock for a dual-axis interbody fusion device. The single fixation plate is attachable to all footprints and configurations of interbody fusion devices.

As in other embodiments of apparatus <NUM>, the spinal system <NUM> allows the surgeon to set the interbody fusion device in fine configurations, especially with any height in highly expanded configurations and at any angle in hyperlordotically adjusted configurations between <NUM>°-<NUM>° for any patient, without further disruption to the patient anatomy caused by additional surgery needed for an independent screw and plate system. Therefore, the spinal system <NUM> can provide complete personalization for the patient, allowing the surgeon to adjust the interbody fusion device to any unique height and/or angle (e.g. <NUM>°) needed for the patient's spinal balance profile. Conventional techniques may allow for an interbody fusion device to be set at only a few predetermined lordotic configurations such as <NUM>°, <NUM>°, <NUM>°, and separate screw and plate systems have to be used through an additional surgery to stabilize the fusion device in a lordotic configuration.

The spinal system <NUM> can also increase surgery efficiency. Conventionally, surgeons have to perform impactful trialing, or sizing of the implant to determine the size of an implant needed for a specific patient. According to embodiments of the disclosure, the interbody fusion device can start at a smaller contracted height and then increase in height. This allows for streamlining or drastically reducing the trialing process, which can in turn decrease the barbaric and rough impact associated with the trialing process. Once the surgeon adjusts the fusion device to the patient's unique spinal profile e.g. sagittal balance profile such as the intervertebral disc height and lordosis, a single fixation plate can be inserted through the same surgical approach and attached to the interbody fusion device to secure the fusion device to the vertebral bodies, causing less disruption to the patient anatomy. The single fixation plate can also provide supplemental fixation, eliminating the need for a separate plate and screw fixation system through a separate surgical approach to the patient's spine.

The spinal system <NUM> also provides benefits pertaining manufacturing and hospital administration. It can reduce inventory. A single set of a fixation plate can work with a dual-axis adjustable interbody fusion device of any size and configuration of a making, thereby drastically reducing manufacturing and operational costs. The use of a single set of a fixation plate with any dual-axis interbody fusion device size and configuration simplifies the need of tracking, by tracking only one set of fixation plates in the hospital or the operating room.

With reference to <FIG>, an example dual-axis adjustable spinal system <NUM> according to embodiments of the disclosure will now be described. The spinal system <NUM> shown in <FIG> is similar in many aspects to the spinal system <NUM> described above in conjunction with <FIG>. For example, the spinal system <NUM> comprises a single fixation plate for attachment to an interbody fusion device in situ following adjustment of the interbody fusion device to a desired configuration in adjacent vertebrae. The single fixation plate can be constructed from a material having sufficient strength to provide supplemental fixation, in addition to providing stabilization and preventing migration of the interbody fusion device. Some unique aspects of the spinal system <NUM> are set forth below.

With reference to <FIG>, the spinal system <NUM> comprises an interbody fusion device <NUM> and a fixation assembly <NUM>. The interbody fusion device <NUM> may be the same as or similar to the device <NUM> described above in conjunction with <FIG>. The fixation assembly <NUM> comprises a single fixation plate <NUM>, at least a first fastener <NUM>, and at least a second fastener <NUM>. The single fixation plate <NUM> is provided with at least a first aperture <NUM> configured for insertion of the first fastener <NUM> therethrough to secure to a first vertebral body, and at least a second aperture <NUM> configured for insertion of the second fastener <NUM> therethrough to secure to a second vertebral body. The single fixation plate <NUM> is configured to be insertable to the interbody fusion device <NUM>, allowing the single fixation plate <NUM> to be attached to the interbody fusion device <NUM> in situ. The single fixation plate assembly <NUM> may also be attached to the interbody fusion device <NUM> prior to implantation if desired, assuming the interbody fusion device is adjusted prior to implantation. The single fixation plate <NUM> may have an attachment-lock mechanism <NUM> configured to secure the attachment of the single fixation plate <NUM> to the interbody fusion device <NUM>. According to certain embodiments, the single fixation plate <NUM> is rotatable relative to the interbody fusion device <NUM>, either clockwise or counterclockwise, as shown in <FIG>. The ability of the single fixation plate <NUM> to rotate relative to the interbody fusion device <NUM> allows the locations of the first aperture <NUM> and the second aperture <NUM> to be adjusted relative to the vertebral bodies, thereby providing optimal fastener trajectories to increase purchase for the fasteners to the vertebral bodies.

With reference to <FIG>, the single fixation plate <NUM> is similar in many aspects to the single fixation plate <NUM> described above in connection with <FIG>. For instance, the single fixation plate <NUM> may include an attachment-lock mechanism <NUM>, a first fastener-lock mechanism <NUM>, and a second fastener-lock mechanism <NUM>. The construction and operation of the attachment-lock mechanism <NUM> and the fastener-lock mechanisms <NUM> and <NUM> are the same as or similar to the attachment-lock mechanism <NUM> and the fastener-lock mechanisms <NUM> and <NUM> in the single fixation plate <NUM> shown <FIG>, therefore their detailed description is omitted herein for clarity.

With reference to <FIG>, the single fixation plate <NUM> may also include a protruding portion <NUM> configured to be insertable into the interbody fusion device <NUM>, or allowing the single fixation plate <NUM> to be attached with the interbody fusion device <NUM> to stabilize and/or prevent migration of the interbody fusion device <NUM> placed between adjacent vertebrae. The attachment of the single fixation plate <NUM> to the interbody fusion device <NUM> restricts unwanted translational movement of the interbody fusion device <NUM> in any of the lateral, anterior, and posterior directions. The attachment of the single fixation plate <NUM> to the interbody fusion device <NUM> may be secured or locked by the attachment-lock mechanism <NUM>, as shown in <FIG> shows the attachment of the single fixation plate <NUM> to the interbody fusion body <NUM> and the attachment-lock mechanism <NUM> in an unlocked state. <FIG> shows the attachment of the single fixation plate <NUM> to the interbody fusion body <NUM> and the attachment-lock mechanism <NUM> in a locked state, where the latch 340d of the attachment-lock mechanism <NUM> hooks to a component (e.g. the thrust bearing) in the interbody fusion device <NUM>.

According to certain embodiments of the disclosure, the protruding portion <NUM> is configured to allow the single fixation plate <NUM> to be rotatable relative to the interbody fusion device <NUM>. For instance, the protruding portion <NUM> may have a geometry generally in the shape of a semi-cylinder, which can be received in an internal component(s) such as a channel geometry built in the inner surface of the superior shell member <NUM> of the interbody fusion device <NUM>. The semi-cylinder geometry of the protruding portion <NUM> allows the single fixation plate <NUM> to be rotatable relative to the interbody fusion device <NUM>, thereby allowing the orientation or angle of the single fixation plate <NUM> to be adjusted before being fastened to the vertebral bodies. According to certain embodiments of the disclosure, the single fixation plate <NUM> can be rotated relative to an imaginary plane containing the first and second drive shafts <NUM>, <NUM>, clockwise or counterclockwise, at an angle from <NUM>-<NUM> degree. <FIG> is an end view showing the angulation of the single fixation plate <NUM> relative to the interbody fusion device <NUM>. <FIG> is a cross-sectional view showing the angulation of the single fixation plate <NUM> relative to the interbody fusion device <NUM>. The lateral sides of the single fixation plate <NUM> may be configured to accommodate the first and second drive shafts <NUM> and <NUM> of the interbody fusion device <NUM> when the single fixation plate <NUM> is rotated relative to the interbody fusion device <NUM>. As shown in <FIG>, recess, cutout or the like <NUM> may be provided at the lateral sides of the single fixation plate <NUM> to allow for the angulation of the single fixation plate <NUM> relative to the interbody fusion device <NUM>. <FIG> are isometric views showing the recess or cutout <NUM> in the lateral sides of the single fixation plate <NUM>, allowing for the angulation of the single fixation plate <NUM> without interference with the drive shafts <NUM> and <NUM> in the interbody fusion device <NUM>.

<FIG> illustrate that the single fixation plate <NUM> can be attached to the interbody fusion device <NUM> in various configurations, including a contracted configuration, a fully expanded configuration, and a lordotically or hyperlordotically adjusted configuration respectively. By way of example where the interbody fusion device <NUM> is placed between adjacent vertebrae via a lateral surgical procedure, <FIG> shows that the single fixation plate <NUM> can be attached to the interbody fusion device <NUM> in a contracted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an example where the single fixation plate <NUM> is attached to the interbody fusion device <NUM> in a fully expanded configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an example where the single fixation plate <NUM> is attached to the interbody fusion device <NUM> in a hyperlordotically adjusted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an example where the interbody fusion device <NUM> in a hyperlordotically adjusted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. In comparison of <FIG> with <FIG>, the single fixation plate <NUM> in <FIG> is rotated at an angle of <NUM> degree with respect to an imaginary plane containing the first and second drive shafts. The angulation of the single fixation plate <NUM> allows the position of the apertures <NUM>, <NUM> in the single fixation plate <NUM> to be adjusted e.g. according to the expanded and/or lordotically adjusted configuration of the interbody fusion device <NUM>, to provide for optimal fastener trajectories to the vertebral bodies.

The dual-axis adjustable spinal system with <NUM> can be used for treatment of various spinal diseases including but not limited to degenerative disc disease (DDD), spondylolisthesis, retrolisthesis (Grade <NUM>). Further, the fixation assembly <NUM> can also be used to provide supplemental fixation in treatment of degenerative disc disease (DDD), spondylolisthesis, trauma (fractures and dislocations), deformities of curvatures (scoliosis, kyphosis, and/or lordosis), tumor, pseudoarthrosis, and failed previous fusion, trauma, tumors, deformities, pseudoarthrosis, previous failed fusions, and so on. The use, benefits, and advantages of the single system <NUM> are similar to those provided by the spinal system <NUM> described above in conjunction with <FIG>, therefore the detailed description is omitted herein for clarity. One uniqueness is the variable aspect of the single fixation plate <NUM> in the spinal system <NUM>. Because of the lack of male geometries mated with female geometries in the drive shafts, the single fixation plate <NUM> is capable of rotating relative to the interbody fusion device <NUM> in situ, allowing the locations of apertures in the single fixation plate <NUM> to be adjusted. <FIG> show an embodiment where the interbody fusion device <NUM> is secured in the vertebral bodies <NUM> and <NUM> by the single fixation plate <NUM>.

With reference to <FIG>, embodiments of a dual-axis adjustable interbody fusion device with integrated fixation or apparatus <NUM> according to the disclosure will now be described. The integrated design allows the fixation plates to be implanted along with the interbody fusion device and angle-adjusted with the expansion and/or adjustment of the interbody fusion device in situ, providing stabilization and preventing migration of the interbody fusion device in the vertebral bodies.

As shown in <FIG>, the apparatus <NUM> in general comprises an interbody fusion device <NUM> and a fixation assembly <NUM>. The interbody fusion device <NUM> may be the same as, or similar to, the example dual-axis adjustable interbody fusion device <NUM> described above in conjunction with <FIG>. Alternatively, the fusion device <NUM> can be any other dual-axis adjustable interbody fusion devices available from various manufacturers, which can be further adapted or modified for use with the fixation assembly <NUM>.

The fixation assembly <NUM> comprises a first or inferior fixation plate <NUM> and a second or superior fixation plate <NUM>. The fixation assembly <NUM> also comprises a first fastener <NUM> and a second fastener <NUM>. According to certain embodiments of the disclosure, the inferior fixation plate <NUM> is coupled to the inferior shell member <NUM> and configured for placement with the interbody fusion device <NUM>. Likewise, the superior fixation plate <NUM> is coupled to the superior shell member <NUM> and configured for placement with the interbody fusion device <NUM>. In certain embodiments, the inferior fixation plate <NUM> can be integrally formed with the inferior shell member <NUM>. For instance, the inferior fixation plate <NUM> and the inferior shell member <NUM> can be formed as a single part, or the inferior fixation plate <NUM> can be made as a separate piece and then welded to or integrated with the inferior shell member <NUM>. Alternatively, the inferior fixation plate <NUM> may be formed as a separate part and coupled to the inferior shell member <NUM> by interference fit, screw coupling, or any other suitable means. Likewise, the superior fixation plate <NUM> can be integrally formed with the superior shell member <NUM> by e.g. being made as a single piece, or separate pieces and then welded together. Alternatively, the superior fixation plate <NUM> may be formed as a separate part and coupled to the superior shell member <NUM> by interference fit, screw coupling, or any other suitable means. The integrated design allows the inferior fixation plate <NUM> and the superior fixation plate <NUM> to be implanted along with the interbody fusion device <NUM>. The coupling of the inferior fixation plate <NUM> with the inferior shell member <NUM> and of the superior fixation plate <NUM> with the superior shell member <NUM> allows the inferior fixation plate <NUM> and superior fixation plate <NUM> to be angle-adjusted with the expansion and/or adjustment of the interbody fusion device <NUM> in situ.

The inferior fixation plate <NUM> is provided with an aperture <NUM> configured for insertion of the first fastener <NUM> therethrough to secure to a first vertebral body. The superior fixation plate <NUM> is provided with an aperture <NUM> configured for insertion of the second fastener <NUM> therethrough to secure to a second vertebral body. According to certain embodiments of the disclosure, either or both of the inferior fixation plate <NUM> and the superior fixation plate <NUM> may be sized and/or shaped to minimize or reduce the profile of the fixation plates. A reduced profile of the inferior fixation plate <NUM> and/or the superior fixation plates <NUM> allows for improved visualization of the apparatus <NUM> inside the patient especially e.g. in a lateral view when implanted via a lateral approach. A reduced profile of the inferior fixation plate <NUM> and/or the superior fixation plates <NUM> also facilitates insertion and placement of the apparatus <NUM> in the patient anatomy. By way of example, either or both of the inferior fixation plate <NUM> and the superior fixation plates <NUM> may be in the form of a screw loop or bracket, wherein the fastener apertures <NUM> and/or <NUM> are formed or situated adjacent to the peripheral of the inferior fixation plate <NUM> and/or the superior fixation plate <NUM> so that the overall profile of the inferior fixation plate <NUM> and superior fixation plate <NUM> can be minimized.

According to certain embodiments of the disclosure, the aperture <NUM> in the inferior fixation plate <NUM> and the aperture <NUM> in the superior fixation plate <NUM> may be configured to allow the trajectory of the first fastener <NUM> and the second fastener <NUM> to be adjustable in a caudal or cephalad direction as shown in <FIG>. By way of example, the aperture <NUM> in the inferior fixation plate <NUM> and the aperture <NUM> in the superior fixation plate <NUM> can be cut such that the centerlines of the apertures <NUM> and <NUM> form an angle of e.g. <NUM>-<NUM> degrees relative to a reference plane such as the inferior shell member or the superior shell member, as described above in conjunction with <FIG>. Alternatively, or additionally, the first fastener <NUM> and the second fastener <NUM> may be sized or shaped to allow the fastener trajectory to be adjustable. For example, the first and second fasteners <NUM>, <NUM> may have a head portion in a spherical or tapered shape as shown in <FIG>, allowing for an adjustable fastener trajectory. In general, the trajectory of the first fastener <NUM> and the second fastener <NUM> is capable of being angled from <NUM>-<NUM> degrees relative to the inferior shell member <NUM> or superior shell member <NUM> respectively, e.g. in a caudal or cephalad direction, providing an optimal fastener trajectory to maximize or increase the purchase for the fastener to the vertebral bodies.

With reference to <FIG>, the inferior fixation plate <NUM> may include a lock mechanism <NUM> for preventing the fastener <NUM> from backing out. Likewise, the superior fixation plate <NUM> may include a lock mechanism <NUM> for preventing the fastener <NUM> from backing out. The lock mechanism <NUM> in the inferior fixation plate <NUM> may be the same as or similar to the lock mechanism <NUM> in the superior fixation plate <NUM>. For example, the lock mechanism <NUM> in the superior fixation plate <NUM> may include a lock rod 446a received in a recess 446b adjacent to the aperture <NUM> in the superior fixation plate <NUM>, and an adapter 446c welded or attached to an end of the lock rod 446a to retain the lock rod in the recess and allow the lock rod to turn. As better viewed in <FIG>, the head of the lock rod 446a may have a rounded side portion 446a-<NUM>, a flat side portion 446a-<NUM>, and an end 446a-<NUM> having a feature such as a female hexalobe feature configured to receive a driver for actuating the lock mechanism <NUM>. When the lock rod 446a is turned to set the lock mechanism <NUM> to an unlocked or open state, the head flat side portion 446a-<NUM> faces the aperture <NUM> in the fixation plate <NUM> as shown in <FIG>, leaving the aperture <NUM> open to allow the fastener <NUM> to insert through. After the fastener <NUM> is driven all the way through into a vertebral body and the fastener head received in the countersink of the aperture as shown in <FIG>, the lock rod 446a can be turned to set the lock mechanism <NUM> in a locked state, where the head rounded side portion 446a-<NUM> extends over at least a portion of the aperture <NUM> or over the fastener <NUM>, prohibiting the fastener <NUM> from backing out. The lock mechanism <NUM> of the disclosure allows quick "one-step" locking, requiring only one turn of the lock rod 446a with a driving tool to lock or unlock the fastener. The use of a "one-step" locking mechanism can also simplify or reduce the profile of the fixation plate, which is beneficial for inserting and placing the apparatus in the patient anatomy.

With reference now to <FIG>, the integrated fixation plates <NUM>, <NUM> of the disclosure can stabilize and prohibit migration of the interbody fusion device <NUM> in any expanded or adjusted configurations in the adjacent vertebrae. <FIG> shows an embodiment where the example interbody fusion device <NUM> is in a fully expanded configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. <FIG> shows an embodiment where the example interbody fusion device <NUM> is in a hyperlordotically adjusted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree. While kyphotic (negative lordosis) adjustments may not be desirable for the lumbosacral segment of the spine, the interbody fusion device <NUM> can be hyperkyphotically adjusted. The inferior fixation plate <NUM> and the superior fixation plate <NUM> move with the inferior shell member <NUM> and the superior shell member <NUM> during the expansion and/or lordotic adjustment of interbody fusion device <NUM>, allowing the position and/or angle of the apertures in the inferior and superior fixation plates <NUM>, <NUM> to be automatically adjusted. In either of the device configurations shown in <FIG>, the fastener trajectory can be further varied at an angle from <NUM> to <NUM> degrees, e.g. in a caudal or cephalad direction, allowing for an optimal fastener trajectory to maximize or increase the purchase for the fastener to the vertebral body. <FIG> shows an embodiment where the interbody fusion device <NUM> is in a contracted configuration having an anterior height of <NUM>, a posterior height of <NUM>, and a lordosis of <NUM> degree.

The dual-axis adjustable interbody fusion device with integrated fixation <NUM> can be used in treatment of various spinal diseases, including but not limited to degenerative disc disease (DDD), spondylolisthesis, retrolisthesis (Grade <NUM>), and so on. With reference to <FIG>, in use the interbody fusion device with integrated fixation <NUM> in a contracted configuration can be inserted in the patient anatomy and placed between adjacent vertebrae <NUM>, <NUM> using a suitable operation instrument <NUM>. Suitable surgical procedure for introducing the interbody fusion device in the patent anatomy include a lateral lumbar interbody fusion (LLIF) procedure, an anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF) procedure, and any other suitable surgical procedures performed in the lumbar or other regions of the spinal column. Various suitable operation instruments are described in <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Fusion Systems" and <CIT> entitled "Surgical Operating Instrument for Expandable and Adjustable Lordosis Interbody Fusion Systems". The interbody fusion device <NUM> can be expanded and/or lordotically adjusted using the operation instrument <NUM>, forming a suitable configuration between the adjacent vertebrae <NUM>, <NUM>.

Fasteners such as bone screws <NUM>, <NUM> can be then inserted through the apertures in the inferior and superior fixation plates <NUM>, <NUM> and driven into the first vertebral body <NUM> and the second vertebral body <NUM> respectively. Once the fasteners <NUM>, <NUM> are driven all the way and the heads of the fasteners are received in the apertures in the fixation plates, the "one-step" lock mechanisms in the inferior and superior fixation plates <NUM>, <NUM> can be actuated using the operation instrument <NUM> to lock the fasteners <NUM>, <NUM> to prevent them from backing out. The interbody fusion device <NUM> can be then stabilized and prevented from migrating in the vertebral bodies <NUM>, <NUM>, as shown in <FIG>.

Embodiments of a dual-axis adjustable interbody fusion device with integrated fixation <NUM> are described in conjunction with <FIG>. Beneficially, the interbody fusion device with integrated fixation <NUM> can stabilize and prohibit migration of an interbody fusion device in any configuration, from a less expanded configuration to a fully expanded configuration and/or hyperlordotically adjusted configurations to safely promote fusion between two adjacent vertebral bodies. Interbody fusion devices of any size and configuration can be integrated with the fixation plates of the disclosure and configured to be insertable via a single surgical approach and patient position to minimize disruption to the patient anatomy. The integration of inferior and superior fixation plates with an interbody fusion device allows angulation of the fastener aperture and thus the fastener trajectory to follow the angulation of the inferior and superior shell members of the interbody fusion device respectively, at any angle from <NUM>-<NUM> degrees, providing for ideal fastener trajectory and placement. Other benefits and advantages are same as or similar to those provided by the interbody fusion device with modular fixation <NUM> described above in connection with description of the <FIG>, and their detailed description is omitted herein.

According to embodiments of the disclosure, the first and second drive shafts <NUM> and <NUM> of the interbody fusion device <NUM> in the apparatuses <NUM> and <NUM> or in the systems <NUM> and <NUM> can be continuously operable to allow the distance between the inferior and superior shell members <NUM> and <NUM> at the first and/or second lateral areas of the housing to be continuously changeable, thereby allowing the height of the expanded configuration of the interbody fusion device <NUM> to continuously change. By way of example, the height of the interbody fusion device <NUM> can continuously change by <NUM> to <NUM> millimeters. Additionally, or alternatively, the first and second drive shafts <NUM> and <NUM> of the interbody fusion device <NUM> in the apparatuses <NUM> and <NUM> or in the systems <NUM> and <NUM> can be continuously operable to allow the angle between the inferior and superior shell members <NUM> and <NUM> to be continuously changeable, thereby allowing the lordosis of the expanded configuration of the interbody fusion device <NUM> to continuously change. By way of example, the lordosis of the interbody fusion device <NUM> can continuously from <NUM> to <NUM> degrees.

All technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art unless specifically defined otherwise. As used in the description and appended claims, the singular forms of "a," "an," and "the" include plural references unless the context clearly dictates otherwise. The term "or" refers to a nonexclusive "or" unless the context clearly dictates otherwise. The term "first" or "second" is used to distinguish one element from another in describing various similar elements and should not be construed as in any particular order unless the context clearly dictates otherwise.

Claim 1:
An apparatus comprising an interbody fusion device (<NUM>) and a fixation assembly (<NUM>, <NUM>, <NUM>, <NUM>),
the interbody fusion device (<NUM>) comprising a housing (<NUM>), a first wedge member (14a, 14b), a second wedge member (16a, 16b), a first drive shaft (<NUM>), and second drive shaft (<NUM>), wherein
the housing (<NUM>) comprises a first shell member (<NUM>) and a second shell member (<NUM>), the first and second shell members (<NUM>, <NUM>) engaging the first wedge member (14a, 14b) along a first lateral area (<NUM>) of the housing, engaging the second wedge member (16a, 16b) along a second lateral area (<NUM>) of the housing,
the first wedge member (14a, 14b) is provided with a through-opening configured to allow the first drive shaft (<NUM>) to pass, the second wedge member (16a, 16b) is provided with a through-opening configured to allow the second drive shaft (<NUM>) to pass, and
the first drive shaft (<NUM>) is operable to drive the first wedge member (14a, 14b) along the first lateral area (<NUM>) of the housing, the second drive shaft (<NUM>) is operable to drive second wedge member (16a, 16b) along the second lateral area (<NUM>) of the housing, causing the first and second shell members (<NUM>, <NUM>) to move relative to each other providing an expanded configuration of the interbody fusion device (<NUM>),
the fixation assembly (<NUM>, <NUM>, <NUM>, <NUM>) comprising a first fixation plate (<NUM>, <NUM>, <NUM>, <NUM>) having a first aperture (<NUM>, <NUM>, <NUM>, <NUM>) for insertion of a first fastener (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the first fixation plate (<NUM>, <NUM>, <NUM>, <NUM>) is modular configured to be attachable to the interbody fusion device (<NUM>), thereby allowing the first fixation plate (<NUM>, <NUM>, <NUM>, <NUM>) to be attached to the interbody fusion device (<NUM>) in the expanded configuration in situ and fastened to a first vertebral body (<NUM>) to stabilize and/or prevent migration of the interbody fusion device (<NUM>).