Translationally mobile, dual-axis adjustable intervertebral fusion spinal system

Abstract

An intervertebral fusion device that employs a torque transmission mechanism to transmit torque to a drive mechanism that is responsible for expanding the intervertebral fusion device in a direction that is not parallel to the longitudinal axis of the drive mechanism.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to devices, systems, and methods for treating spinal disorders. In particular, various embodiments of expandable and adjustable lordotic intervertebral fusion devices are described. BACKGROUND

[0002] Spinal fusion is a surgical procedure that corrects problems associated with the human spine, such as degenerative disc disease (DDD), spondylolisthesis, recurrent disc herniation, etc. Spinal fusion generally involves removing the damaged intervertebral disc and bone between adjacent vertebrae and inserting bone graft material that promotes bone growth. As the bone grows, the adjacent vertebrae are joined or fused together. Fusing the bones together can help stabilize a particular region of the spine and help reduce problems associated with nerve stimulation at the fusion site. Fusion can be performed at one or more segments of the spine.

[0003] In intervertebral spinal fusion surgery, the nucleus pulposus and / or annulus fibrosus that make up the intervertebral disc at the point of injury are removed, and an implant configured in shape and size is placed in the intervertebral disc space to restore the distance between adjacent vertebrae to a proper state. Surgical methods to perform intervertebral fusion are varied and can access the patient's spine through the abdomen or the back. One surgical method for achieving lumbar fusion in a less invasive manner includes accessing the spine through a small incision on the posterior side, where the surgeon removes a portion of the bone and joint on the posterior and lateral portions of the vertebrae. These segments of bone and joint are referred to as the lamina and facet joint, respectively. This surgery is referred to as transforaminal lumbar interbody fusion (TLIF). The transforaminal technique allows the surgeon to insert the bone graft and spacer from a unilateral approach laterally into the intervertebral disc space without having to forcefully retract the nerve root, which can reduce injury and scarring around the nerve root compared to more traditional posterior lumbar interbody fusion (PLIF) that requires nerve root retraction and a bilateral approach. Other common surgical methods or approaches for reaching the desired intervertebral disc of interest are through the anterior and / or anterolateral column of the spine. Lateral lumbar interbody fusion (LLIF) is a minimally invasive procedure in which the surgeon accesses the spine through a small surgical incision on the side, with or without cutting the psoas major muscle, which is also referred to as anterior-to-psoas lateral lumbar interbody fusion (ATP LLIF). The LLIF and ATP LLIF procedures allow for delivery of larger intervertebral fusion device profiles with minimal disruption to the patient's anatomy and enable indirect decompression of the nerve root elements. Anterior lumbar interbody fusion (ALIF) is a procedure in which the surgeon accesses the desired intervertebral disc of interest through an open incision in the abdomen by navigating through the abdominal muscles and around organ and vascular structures. The ALIF procedure allows for delivery of larger intervertebral fusion devices compared to any other intervertebral fusion procedure, which in turn provides good indirect decompression and prevents the risk of the delivered implant settling or sinking into the vertebral body elements.

[0004] Conventionally, once the intervertebral disc is removed from the body, the surgeon typically applies pressure between the vertebral bodies in the particular region with different trial implants to determine the size of the implant to maintain the appropriate distance between adjacent vertebrae. The appropriate angle between the vertebral bodies must also be maintained to accommodate the natural curvature of the spine, e.g., lordosis. Thus, both the intervertebral disc height and lordosis must be considered during selection of the fusion device for implantation. Conventional implant devices are typically pre-configured with a top surface angle and a bottom surface angle to accommodate the natural curvature of the spine. It is unlikely or difficult to precisely determine these values prior to operation. Furthermore, in implementing a trial and error approach to determine the size of the intervertebral fusion device and fitting the intervertebral fusion device into the target region for geometric configuration, the patient is subjected to significant invasive activity. If an over-lordotic sagittal profile configuration (>20°) is set or supplemental fixation to the lumbosacral level is required, the surgeon can place a spinal member in the form of an anterior column fixation, such as an additional bone plate and screw assembly, to prevent possible migration 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 procedure until arthrodesis is performed. This can require the surgeon to perform a second surgery after placement of the fusion device, which in turn will extend the overall procedure time, resulting in a more likely blood loss and anesthesia complications for the patient. SUMMARY

[0005] An example intervertebral fusion device includes a housing, a drive mechanism operable to expand and / or contract the housing, and a gear assembly operable to transmit torque to the drive mechanism. The drive mechanism includes a shaft having a longitudinal axis. The gear assembly includes a first translation gear coupled to the shaft and a first drive gear configured to receive torque applied from a direction that is not parallel to the longitudinal axis of the shaft and drive the first translation gear, whereby application of torque to the first drive gear rotates the first translation gear and the shaft about the longitudinal axis to actuate the drive mechanism to expand and / or contract the housing.

[0006] An example intervertebral fusion device includes a housing, a first drive mechanism, a second drive mechanism, a first gear assembly, and a second gear assembly. The first drive mechanism is disposed in the housing at a first lateral region. The second drive mechanism is disposed in the housing at a second lateral region. The first drive mechanism includes a first shaft having a longitudinal axis. The second drive mechanism includes a second shaft having a longitudinal axis. The first gear assembly is operable to transmit torque to the first drive mechanism. The first gear assembly includes a translation gear coupled to the first shaft and a drive gear configured to receive torque applied from a direction that is not parallel to the longitudinal axis of the first shaft and to drive the translation gear, whereby application of torque to the drive gear rotates the translation gear and the first shaft about the longitudinal axis of the first shaft, thereby actuating the first drive mechanism to effect expansion and / or contraction of the housing at the first lateral region. The second gear assembly is operable to transmit torque to the second drive mechanism. The second gear assembly includes a first translation gear coupled to the second shaft and a first drive gear configured to receive torque applied from a direction that is not parallel to the longitudinal axis of the second shaft and to drive the first translation gear, whereby application of torque to the first drive gear rotates the first translation gear and the second shaft about the longitudinal axis of the second shaft, thereby actuating the second drive mechanism to effect expansion and / or contraction of the housing at the second lateral region.

[0007] This Summary is provided to introduce a selection of embodiments in a simplified form that are further described below in the and are not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used to determine the scope of the claimed subject matter. The selection is merely presented to provide the reader with a brief overview of some forms the present disclosure can take and is not intended to limit the scope of the disclosure. Other aspects and embodiments of the present disclosure are described in the detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0008] These and various other features and advantages of the present disclosure will be better understood and appreciated, as the same becomes better understood, by reference to the following detailed description and by reference to the accompanying drawings, wherein:

[0009] Figures 1A-1D An example intervertebral fusion device according to embodiments of the present disclosure is depicted. Figure 1A is an isometric view, Figure 1B is a top view, Figure 1C is a partial exploded view, and Figure 1D is a cross-sectional view.

[0010] Figures 2A-2C An example intervertebral fusion device of the present disclosure is depicted in conjunction with a surgical instrument. Figure 2A is a perspective view, Figure 2B is an enlarged perspective view, and Figure 2C is an enlarged side view.

[0011] Figures 3A-3D Figures illustrate engagement of example dual-axial intervertebral fusion devices of the present disclosure with surgical instruments in various modes of operation. Figure 3A is a cross-sectional view highlighting first and second drivers of a surgical instrument, Figure 3B is a cross-sectional view showing engagement of an intervertebral fusion device with a surgical instrument in an expansion mode (simultaneous dual-axial adjustment), Figure 3C is a cross-sectional view showing engagement of an intervertebral fusion device with a surgical instrument in an anterior lordosis mode (independent anterior axial adjustment), and Figure 3D is a cross-sectional view showing engagement of an intervertebral fusion device with a surgical instrument in another anterior lordosis mode (independent posterior axial adjustment).

[0012] Figure 4 is a partial exploded view of an example intervertebral fusion device illustrating simultaneous adjustment of both sets of drive gears and axles of the intervertebral fusion device together (simultaneous dual-axial adjustment), which in turn drives both translation axles together, resulting in a parallel expansion mode of operation.

[0013] Figure 5 is a partial exploded view of an example intervertebral fusion device illustrating independent operation of drive gears and axles within only the second lateral portion of the intervertebral fusion device (independent anterior axial adjustment), which in turn drives only the translation axles in the second lateral portion of the intervertebral device, resulting in an unequal expansion or lordosis mode of operation.

[0014] Figure 6 is a partial exploded view of an example intervertebral fusion device illustrating independent operation of drive gears and axles within only the first lateral portion of the intervertebral fusion device (independent posterior axial adjustment), which in turn drives only the translation axles in the first lateral portion of the intervertebral device, resulting in an unequal expansion or lordosis mode of operation.

[0015] Figure 7 depicts an example intervertebral fusion device in an expanded configuration.

[0016] Figure 8 depicts an example intervertebral fusion device in an anterior lordosis adjustment configuration.

[0017] Figures 9A-9B depicts an example intervertebral fusion device placed between adjacent vertebrae. Figure 9A is a front view, and Figure 9B is a side view.

[0018] Figures 10A-10B depicts an example intervertebral fusion device and fixation assembly according to embodiments of the present disclosure. Figure 10A is an exploded view, and Figure 10B is an assembled view.

[0019] Figure 11 An example fixation plate according to embodiments of the present disclosure is depicted.

[0020] Figures 12A-12B An example fixation plate to example intervertebral fusion device according to embodiments of the present disclosure is depicted. Figure 12A is an exploded view, and Figure 12B is an assembled cross-sectional view.

[0021] Figures 13A-13B Another example fixation plate to example intervertebral fusion device according to embodiments of the present disclosure is depicted. Figure 13A is an exploded view, and Figure 13B is an assembled cross-sectional view.

[0022] Figures 14A-14C An example fixation plate to example intervertebral fusion device using a surgical instrument and fixation of the intervertebral fusion device to adjacent vertebrae is illustrated. DETAILED DESCRIPTION

[0023] Referring to the drawings, various embodiments of an intervertebral fusion device will now be described, in which like reference numerals refer to like parts throughout the various drawings. It should be noted that the drawings are merely intended to facilitate description of the embodiments and are not intended to limit the scope of the present disclosure. Furthermore, certain specific details are shown in the drawings and in the description in order to provide a thorough understanding of various embodiments of the present disclosure. Those skilled in the art will understand that the claimed application can be practiced without these details. In other instances, well-known components, structures or steps have not been shown or described in order to avoid unnecessarily obscuring the description of the embodiments of the present disclosure. It is also noted that certain aspects or features of the embodiments described in connection with the present disclosure can not necessarily be limited to a single embodiment and can be practiced or implemented in any number of embodiments.

[0024] Generally, various embodiments of intervertebral fusion devices include a drive mechanism operable to expand and / or contract the intervertebral fusion device and a torque transmission mechanism operable to transmit torque to the drive mechanism in a direction that is not parallel, e.g., perpendicular, to the drive mechanism. The intervertebral fusion device can be a dual-axially adjustable intervertebral fusion device that includes a first drive mechanism and a second drive mechanism. The first and second drive mechanisms can be operated simultaneously or independently by the torque transmission mechanism, thereby allowing simultaneous or independent control of the expansion and / or lordotic adjustment of the intervertebral fusion device. By way of example, an example intervertebral fusion device in a contracted configuration can be inserted into a patient and placed between adjacent vertebrae with the first drive mechanism of the intervertebral fusion device positioned along the posterior side of the patient and the second drive mechanism of the intervertebral fusion device positioned along the anterior side of the patient. The intervertebral fusion device can then be operated by applying torque forward, e.g., to first and second transmission mechanisms, the first transmission mechanism in a direction generally perpendicular to the first drive mechanism, the first drive mechanism receiving torque from the first transmission mechanism, thereby allowing the first drive mechanism to convert the torque to linear motion, resulting in expansion of the intervertebral fusion device on the posterior side, the second transmission mechanism in a direction generally perpendicular to the second drive mechanism, the second drive mechanism receiving torque from the second transmission mechanism, thereby allowing the second drive mechanism to convert the torque to linear motion, resulting in expansion of the intervertebral fusion device on the anterior side. These transmission and drive mechanisms allow for simultaneous or independent expansion and / or lordotic adjustment of the intervertebral space at the posterior and / or anterior side of the patient to achieve the desired sagittal balance or correct for sagittal imbalance in the patient. While kyphosis (negative lordosis) is not desirable in the lumbosacral segment of the spine, lordotic adjustment (negative lordosis) can be made to the intervertebral fusion devices of the present disclosure if desired.

[0025] Referring to Figures 1A-1DThe example intervertebral fusion device 100 can include an expandable housing 102, a first drive mechanism 200, a second drive mechanism 250, and a torque transmission mechanism 300. The first drive mechanism 200 is disposed in the housing 102 at a first lateral region 104, the first drive mechanism 200 being operable to expand and / or contract the housing at the first lateral region 104. The second drive mechanism 250 is disposed in the housing 102 at a second lateral region 106, the second drive mechanism 250 being operable to expand and / or contract the housing at the second lateral region 106. The torque transmission mechanism 300 is operable to receive torque in a direction that is not parallel, e.g., generally perpendicular, to the first drive mechanism 200 and the second drive mechanism 250, and to transmit the torque to the first drive mechanism 200 and the second drive mechanism 250. As will be described in greater detail below, the torque transmission mechanism 300 can transmit or transfer torque to the first drive mechanism 200 and the second drive mechanism 250 simultaneously or independently, thereby allowing simultaneous or independent control of expansion and / or contraction of the housing 102 at the first lateral region 104 and the second lateral region 106.

[0026] Referring to Figures 1A-1D The housing 102 can include a first or lower housing member 110 and a second or upper housing member 120. The lower housing member 110 and the upper housing member 120 can include one or more openings or windows for receiving bone graft material or allowing bone to pass through as fusion occurs. The sides or edges of the lower member 110 and the upper housing member 120 can include chamfered or rounded portions to facilitate insertion of the intervertebral fusion device 100 into a patient’s anatomy. The surfaces of the lower housing member 110 and the upper housing member 120 can include various features, such as serrations, teeth, recesses, indentations, etc., to help prevent device migration or provide better retention. The surfaces of the lower housing member 110 and the upper housing member 120 can also include a counterbore feature to accept various types of anchors, thereby also helping to prevent migration of the device and / or helping to further stabilize the device.

[0027] The lower housing member 110 can include a plurality of independent standpipe members 112 Figure 1D The upper housing member 120 can include a plurality of independent standpipe members 122 Figure 1D The plurality of independent standpipe members 112 of the lower housing member 110 and the plurality of independent standpipe members 122 of the upper housing member 120 can define a first stepped track run 113 along the first lateral region 104 of the housing 102 and a second stepped track run 123 along the second lateral region 106 of the housing 102 Figure 1D). The height of the plurality of independent riser members 112, 122 can vary along the first stepped track run 113 and the second stepped track run 123. For example, the height of the plurality of independent riser members 112 of the first stepped track run 113 and the plurality of independent riser members 122 of the second stepped track run 123 can continuously increase from the central portion of the stepped track extending distally from the central portion.

[0028] Referring to Figures 1A-1D , the first drive mechanism 200 can include a first spindle or shaft 202 having a longitudinal axis and a first pair of screw members 220, 222. The second drive mechanism 250 can include a second spindle or shaft 252 having a longitudinal axis and a second pair of screw members 270, 272. The first shaft 202 can be disposed at the first lateral region 104 of the housing 102. The second shaft 252 can be disposed at the second lateral side 106 of the housing 102. The first shaft 202 and the second shaft 252 can be substantially parallel.

[0029] The first pair of screw members 220, 222 can each be provided with a through opening configured to allow the first shaft 202 to pass through and engage with the first pair of screw members 220, 222. The second pair of screw members 270, 272 can each be provided with a through opening configured to allow the second shaft 252 to pass through and engage with the second pair of screw members 220, 222. The second shaft 252 can comprise two separate sections 254 and 256 that are assembled, which will be described further below. Rotation of the first shaft 202 causes the first pair of screw members 220, 222 to rotate and travel on a first stepped trackway 113 defined by the separate riser members 112, 122 on the lower and upper housing members 110, 120, thereby converting rotational motion to linear motion. Rotation of the second shaft 252 causes the second pair of screw members 270, 272 to rotate and travel on a second stepped trackway 123 defined by the separate riser members 112, 122 on the lower and upper housing members 110, 120, thereby converting rotational motion to linear motion. In response to the linear motion of the first pair of screw members 220, 222 as they advance along and on the separate riser members 112, 122, the lower and upper housing members 110, 120 move linearly relative to each other, thereby effecting expansion or contraction of the housing 102 at the first lateral region 104. Likewise, in response to the linear motion of the second pair of screw members 270, 272 as they advance along and on the separate riser members 112, 122, the lower and upper housing members 110, 120 move linearly relative to each other, thereby effecting expansion or contraction of the housing 102 at the second lateral region 106. As will be described in greater detail below, the first and second shafts 202, 252 can be simultaneously and independently operated or rotated by a torque transmission mechanism 300. Thus, when the first and second pairs of screw members 220, 222, 270, 272 are rotated to different positions on the first and second stepped trackways 113, 123, the degree of expansion or contraction of the housing 102 at the first lateral region 104 can be simultaneously or independently adjusted relative to the degree of expansion or contraction of the housing 102 at the second lateral region 106.

[0030] The first pair of screw members 220, 222 can be constructed and / or arranged such that the direction orientation of the helical threads of screw member 220 is opposite to the direction orientation of screw member 222, such that the first pair of screw members 220, 222 move in opposite directions relative to each other upon rotation of the first shaft 202. Similarly, the second pair of screw members 270, 272 can be constructed and / or arranged such that the direction orientation of the helical threads of screw member 270 is opposite to the direction orientation of screw member 272, such that the second pair of screw members move in opposite directions relative to each other upon rotation of the second shaft 252.

[0031] The first pair of helical members 220, 222 and the second pair of helical members 270, 272 can each have a tapered configuration and include a root surface and a helical thread. The root surface of the helical members can provide a contact surface for the standpipe members. The helical thread of the helical members can be configured to be received in the gap between adjacent standpipe members. The first pair of helical members 220, 222 and the second pair of helical members 270, 272 can each have a variable root radius and / or helical threads of variable thickness that are similar or different in size from one another. The variable root radius and thread thickness can create a tighter fit between the helical members and the independent standpipe members, which in turn reduces, minimizes, or eliminates undesirable micro-motion between components when the interbody fusion device is in its starting position, expanded position, or lordosis adjustment position. Various embodiments of helical members are described in U.S. Patent No. 9,889,019, U.S. Patent No. 10,188,527, and U.S. Application Serial No. 16 / 569,621, filed September 12, 2019, entitled “Expandable and Adjustable Lordosis Interbody Fusion System.” The entire disclosures of U.S. Patent No. 9,889,019 and U.S. Patent No. 10,188,527, and U.S. Application Serial No. 16 / 569,621 are incorporated by reference herein.

[0032] The positions of the plurality of independent standpipe members 112 on the lower shell member 110 can be offset relative to the positions of the plurality of independent standpipe members 122 on the upper shell member 120 such that the plurality of independent standpipe members 112 of the lower shell member 110 can intermesh with the plurality of independent standpipe members 122 of the upper shell member 120 when the interbody fusion device 100 is in the collapsed configuration.

[0033] Referring to Figures 1A-1D , the torque transmission mechanism 300 allows torque to be applied to the first drive mechanism 200 and the second drive mechanism 250 in a direction that is not parallel, e.g., generally perpendicular, to the longitudinal axis of the first shaft 202 of the first drive mechanism 200 or the longitudinal axis of the second shaft 252 of the second drive mechanism 250. As better observed in Figure 1C , the torque transmission mechanism 300 can include a first gear assembly 310 operable to receive torque and transmit torque to the first drive mechanism 200 and a second gear assembly 350 operable to receive torque and transmit torque to the second drive mechanism 250.

[0034] The first gear assembly 310 can include a translation gear 312 and a drive gear 314. The translation gear 312 can be coupled to or fixedly coupled to the first shaft 202 of the first drive mechanism 200. The first shaft 202 can be a single component or the first shaft 202 can include two separate segments that are press fit and / or welded together to form a single component. The translation gear 312 can be configured to receive torque from the drive gear 314 and rotate, thereby rotating the first shaft 202. Rotation of the first shaft 202 causes the first pair of helical members 220, 222 to rotate and move on the independent standpipe member, thereby causing the first shell member 110 and the second shell member 120 to move linearly relative to one another, thereby causing the housing 102 to expand and / or contract at the first lateral region 104. The drive gear 314 can be configured to receive torque applied in a direction that is not parallel to, e.g., generally perpendicular to, the first shaft 202 and transmit the torque to the translation gear 312. As shown, the drive gear 314 can be coupled to the first shaft 202 via a connecting member 316 Figure 1C and Figure 1D ). For example, the connecting member 316 can include a ring 318 that is received on a radiused portion of the first shaft 202, and an arm 320 that extends from the ring 318 and is received in the drive gear 314. The arm 320 can be threaded or unthreaded to allow the drive gear 314 to rotate about the axis of the arm 320 of the connecting member 316 and limit motion off axis while transmitting torque to the translation gear 312. The drive gear 314 can have an elongated portion 322 that is configured to be rotatably received in a sleeve segment of a drive gear in the second gear assembly 350 Figure 1D ), which will be described in more detail below. The end of the elongated portion 322 of the drive gear 314 of the first gear assembly 310 can be provided with a feature for engagement with a driver in a surgical instrument, e.g., a female hex 324, which will be described in more detail below.

[0035] The translation gear 312 and the drive gear 314 of the first gear assembly 310 can be various types of bevel gears, such as straight bevel gears, helical bevel gears, zero-degree bevel gears, hypoid gears, or conical gears. By way of example, the translation gear 312 and the drive gear 314 can have a pitch of, e.g., 8 mm. Other gear sizes are certainly possible, and the present claims are not limited in this regard. In certain embodiments, the principles of the present disclosure can be implemented with a worm gear.

[0036] The second gear assembly 350 can include a first translation gear 352 and a first drive gear 354. The second gear assembly 350 can also include a second translation gear 362 and a second drive gear 364. In certain embodiments of the present disclosure, the second shaft 252 can include a first section 254 that operates with the helical member 270 and a second section 256 that operates with the helical member 272. Accordingly, the first translation gear 352 of the second gear assembly 350 can be coupled to the first section 254 of the second shaft 252 and configured to rotate the first section 254. Rotation of the first section 254 of the second shaft 252 rotates the helical member 270 and travels along and on the independent riser member. The second translation gear 262 of the second gear assembly 350 can be coupled to the second section 256 of the second shaft 252 and configured to rotate the second section 256. Rotation of the second section 256 of the second shaft 252 rotates the helical member 272 and travels along and on the independent riser member. The first section 254 and the second section 256 of the second shaft 252 can be rotatably connected to a connecting member 370. For example, the connecting member 370 can include a ring 372, a first arm (not shown) extending from the ring and received in the first section 254 of the second shaft 252, and a second arm (not shown) extending from the ring and received in the second section 256 of the second shaft 252. The first arm and the second arm can be threaded or unthreaded to allow rotation of the first section 254 and the second section 256 of the second shaft 252 about an axis of the first arm and an axis of the second arm of the connecting member 370, respectively, while limiting motion off axis.

[0037] The first drive gear 354 of the second gear assembly 350 can be configured to receive a torque applied in a direction that is not parallel, e.g., substantially perpendicular, to the second shaft 352 and transmit the torque to the first translating gear 352 of the second gear assembly 350. The second drive gear 364 of the second gear assembly 350 can be configured to receive a torque applied in a direction that is not parallel, e.g., substantially perpendicular, to the second shaft 252 and transmit the torque to the second translating gear 362 of the second gear assembly 350. For example, the first drive gear 354 can include a feature, e.g., a female hex portion 355, that is configured to engage with a driver in a surgical instrument for receiving a torque in a direction that is substantially perpendicular to the second shaft 252. In certain embodiments, the first drive gear 354 and the second drive gear 364 of the second gear assembly 350 can be configured or assembled to operate as a single unit such that rotation of the first drive gear 354 allows rotation of the second drive gear 364. For example, the first drive gear 354 and the second drive gear 364 can be connected to form a tubular section 374 that can be received in a ring 372 of a connecting member 370, thereby allowing the first drive gear 354 and the second drive gear 364 to rotate as a single unit (364) with the first drive gear 354 being connected to the second drive gear 364. Alternatively, the first drive gear 354 and the second drive gear 364 can be disconnected to form a section with a gap where the section 374 exists to allow independent adjustment, which in turn allows independent or different rotation of the shaft sections 254 and 256, thereby allowing the helical members 270 and 272 to rotate and travel along and on the independent riser members at different locations relative to each other. Figure 1D ) rotate as a single unit. Alternatively, the first drive gear 354 and the second drive gear 364 can be disconnected to form a section with a gap where the section 374 exists to allow independent adjustment, which in turn allows independent or different rotation of the shaft sections 254 and 256, thereby allowing the helical members 270 and 272 to rotate and travel along and on the independent riser members at different locations relative to each other.

[0038] The first drive gear 354 and the first translating gear 352 of the second gear assembly 350 can be bevel gears of various classifications and types. The second drive gear 364 and the second translating gear 362 of the second gear assembly 350 can be bevel gears of various classifications and types. The first drive gear 354 and the second drive gear 364 can have different pitches. For example, the first drive gear 354 can have a pitch of, e.g., 0.8 mm, and the second drive gear 364 can have a pitch of, e.g., 6 mm. Thus, the first translating gear 352 can have a pitch of, e.g., 8 mm, and the second translating gear 362 can have a pitch of, e.g., 6 mm. Other gear dimensions are obviously possible, and the present claims are not limited in this regard. Alternatively, the first drive gear 354 and the second drive gear 364 can have the same pitch, and the first translating gear 352 and the second translating gear 362 can have the same pitch. In certain embodiments, the principles of the present disclosure can be implemented with worm gears.

[0039] In certain embodiments, the torque transmission mechanism 300 can be configured to allow the surgical instrument to simultaneously or independently operate the first gear assembly 310 and the second gear assembly 350. As better observed in Figure 1C and Figure 1D The drive gear 314 of the first gear assembly 310 can include an elongated portion 322. The second drive gear 364 of the second gear assembly 350 can include a sleeve section 366. The elongated portion 322 of the drive gear 314 of the first gear assembly 310 can be rotatably received in the sleeve section 366 of the second drive gear 364 of the second gear assembly 350. This allows the surgical instrument to have two drivers, e.g., a female hex driver and a male hex driver within the female hex driver, to simultaneously and independently operate the first gear assembly 310 and the second gear assembly 350. Thus, the first drive mechanism 200 and the second drive mechanism 250 of the intervertebral fusion device 100 can be simultaneously or independently operated by the surgical instrument via the first gear assembly 310 and the second gear assembly 350, respectively. For example, the end of the elongated portion 322 of the drive gear 314 of the first gear assembly 310 can be provided with a feature 324, e.g., a female hex portion for engagement with a first driver having, e.g., a male hex feature. The passage in the first drive gear 354 and the second drive gear 364 including the sleeve section 366 allows the first driver in the surgical instrument to access the female hex feature 324 in the drive gear 314 of the first gear assembly 310. The first drive gear 354 of the second gear assembly 350 can be provided with a feature 355, e.g., a female hex feature configured for engagement with a second driver having, e.g., a male hex feature.

[0040] Figures 2A-2C A surgical instrument 400 that can be used to operate the example intervertebral fusion device 100 of the present disclosure is shown. Figures 3A-3D The engagement of the surgical instrument 400 with the example dual-axial intervertebral fusion device 100 of the present disclosure is illustrated. Various modes of operation can be achieved by different selectable adjustments of the two axes of the intervertebral fusion device in relation to the two directions of the body perpendicular to the two desired body expansion and / or contraction directions of the desired intervertebral fusion device. For example, simultaneously or independently adjusting the posterior and anterior axes to produce equal or unequal expansion of the intervertebral fusion device in the superior and inferior directions, respectively. As better observed in Figures 3A-3DAs can be better observed, the surgical instrument 400 can include a first driver 410 and a second driver 420. The first driver 410 can be rotatably received in a channel in the second driver 420 and can be extended and retracted into the channel in the second driver 420, thereby allowing the first driver 410 to apply torque independently of or simultaneously with the second driver 420. The first driver 410 of the surgical instrument 400 can include a working end portion having a feature, such as a male hex feature, for engaging a drive gear 314 of the first gear assembly 310, which can include an end having a feature, such as a female hex feature, for example. The second driver 420 of the surgical instrument 400 can include a working end portion having a feature, such as an outer hex feature, for engaging a first drive gear 354 of the second gear assembly 350, which can have a feature, such as a female hex feature.

[0041] Referring to Figure 3B , the first driver 410 of the surgical instrument 400 can be extended to allow the first driver 410 to engage the drive gear 314 of the first gear assembly 310 and to allow the second driver 420 to engage the first drive gear 354 of the second gear assembly 350. Simultaneous operation or turning of the first driver 410 and the second driver 420 of the surgical instrument 400 allows torque to be simultaneously applied to the first gear assembly 310 and the second gear assembly 350, which in turn simultaneously transmits torque to or actuates the first drive mechanism 200 and the second drive mechanism 250 of the intervertebral fusion device 100, thereby effecting expansion or contraction of the intervertebral fusion device 100 at both the posterior portion 104 and the anterior portion 106. Referring to Figure 3C , the first driver 410 of the surgical instrument 400 can be retracted to disengage the drive gear 314 of the first gear assembly 310, thereby allowing only the second driver 420 of the surgical instrument 400 to engage the first drive gear 354 of the second gear assembly 350. Operation or turning of the second driver 420 of the surgical instrument 400 allows torque to be applied only to the second gear assembly 350, which in turn transmits torque only to or actuates only the second drive mechanism 250 of the intervertebral fusion device 100, thereby effecting expansion or contraction of the intervertebral fusion device 100 at the anterior portion 106. Referring to Figure 3D, the first driver 410 of the surgical instrument 400 can extend into engagement with the drive gear 314 of the first gear assembly 310, and the second driver 420 of the surgical instrument 400 can retract out of engagement with the first drive gear 354 of the second gear assembly 350. Operating or turning the first driver 410 of the surgical instrument 400 allows torque to be applied to only the first gear assembly 310, which in turn transmits torque to only the first drive mechanism 200 of the intervertebral fusion device 100 or actuates only the first drive mechanism 200 of the intervertebral fusion device 100, thereby effecting expansion or contraction of the intervertebral fusion device 100 at the posterior portion 104.

[0042] Returning to Figure 1C , the intervertebral fusion device 100 can include a first thrust bearing 105 coupling the first shaft 202 and the second shaft 252 at the first end of the first shaft 202 and the first end of the second shaft 252. Additionally or alternatively, the intervertebral fusion device 100 can include a second thrust bearing 107 coupling the first shaft 202 and the second shaft 252 at the second end of the first shaft 202 and the second end of the second shaft 202. The first thrust bearing 105 and / or the second thrust bearing 107 can be configured to include two parts that can be joined together by, for example, a press fit and / or a weld. The first thrust bearing 105 and / or the second thrust bearing 107 allow the first shaft 202 to rotate about the longitudinal axis of the first shaft and prevent translation or linear movement of the first shaft. Likewise, the first thrust bearing 105 and / or the second thrust bearing 107 allow the first section 254 and the second section 255 of the second shaft 252 to rotate about the longitudinal axis of the second shaft and prevent translation or linear movement of the first section 254 and the second section 256 of the second shaft 252.

[0043] The intervertebral fusion device 100 or at least a portion of the intervertebral fusion device 100 can be composed of a material including a metal such as titanium, tantalum, stainless steel, cobalt-chrome alloy, or any other biocompatible metal or alloy. The intervertebral fusion device 100 or a portion of the intervertebral fusion device 100 can also be composed of a polymeric material such as polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ketone (PEK), or the like.

[0044] The intervertebral fusion device 100 can be any size suitable for a spinal fusion procedure. For example, the distance from one end of the device 100 to the other end along the first drive mechanism 200 or the second drive mechanism 250 ("length") can range from 25 millimeters (mm) to 60 millimeters (mm). The distance from one side of the device to the opposite side ("width") can range from 20 mm to 35 mm. The device can be manufactured in multiple products with different lengths and widths in different increments, for example, 2 mm width increments and 5 mm length increments. The distance from the lower shell member surface to the upper shell member surface of the intervertebral fusion device in the fully collapsed configuration ("base height") can range from 5 mm to 10 mm. The intervertebral fusion device can have different base heights or starting heights at the anterior and posterior sides. For example, the base height at the posterior side can be less than the base height at the anterior side to accommodate the nature of an anterior procedure, allowing for deeper device fitting into the intervertebral space, as shown in Figure 2C Alternatively, the intervertebral fusion device 100 can have the same or similar base heights at the anterior and posterior sides. The dual-axis drive mechanism according to embodiments of the present disclosure can provide continuous expansion of the height in the range of 0 mm to 9 mm and continuous angular formation ("lordosis") between the lower shell member surface and the upper shell member surface in the range of 0 degrees to 30 degrees. It should be noted that the specific dimensions described above are provided for thorough understanding of various aspects of the present disclosure and are not intended to limit the scope of the claims. Other dimensions are obviously possible to one of ordinary skill.

[0045] Example 1: Expansion Mode (Simultaneous Dual-Axis Adjustment)

[0046] Referring to Figure 4 and Figure 1C The expansion mode of the example intervertebral fusion device 100 will now be described. In the expansion mode, the first drive mechanism 200 and the second drive mechanism 250 of the intervertebral fusion device 100 can operate simultaneously, providing parallel expansion or collapse of the intervertebral fusion device 100.

[0047] The intervertebral fusion device 100 in the starting or collapsed configuration can first be placed in the intervertebral space via an anterior surgical procedure. Starting in the expansion mode, the user can use a surgical instrument 400 including a first driver 410 and a second driver 420 as shown in Figures 2A-2C and Figures 3A-3D allowing the first driver 410 to engage the drive gear 314 of the first gear assembly 310 and the second driver 420 to engage the first drive gear 354 of the second gear assembly 350, as shown in Figure 3Bbetter illustrated. The user can then apply torque in a direction generally perpendicular to the drive mechanisms 200, 250 of the intervertebral fusion device 100 by rotating both the first driver 410 and the second driver 420 of the surgical instrument 400, for example, in a clockwise direction as indicated by arrows Al and A2. Figure 4

[0048] Referring to Figure 4 and Figure 1C , rotation of the first driver 410 of the surgical instrument 400 rotates the drive gear 314 of the first gear assembly 310, for example, in a clockwise direction as indicated by arrow Bl, which in turn drives the translation gear 312 in an outward direction, for example, as indicated by arrow B2, thereby rotating the first shaft 202 in an outward direction, for example, as indicated by arrow B2. Rotation of the first shaft 202 causes the helical members 220, 222 to travel in an outward direction on the riser member, for example, as indicated by arrow B3, thereby causing the inferior shell member 110 and the superior shell member 120 of the intervertebral fusion device 100 to move linearly relative to one another, for example, to expand at the posterior portion 104 as indicated by arrow B4.

[0049] Referring to Figure 4 and Figure 1C , rotation of the second driver 420 of the surgical instrument 400 rotates the first drive gear 354 of the second gear assembly 350, for example, in a clockwise direction as indicated by arrow Cl, which in turn drives the first translation gear 352 in an outward direction, for example, as indicated by arrow C2, thereby rotating the first section 254 of the second shaft 252 in an outward direction, for example, as indicated by arrow C2. Rotation of the first section 254 of the second shaft 252 causes the helical member 270 to travel in an outward direction on the riser member, for example, as indicated by arrow C3.

[0050] Still referring to Figure 4 and Figure 1C , rotation of the second driver 420 of the surgical instrument 400 also rotates the second drive gear 364 of the second gear assembly 350, for example, in a clockwise direction as indicated by arrow Dl, which in turn drives the second translation gear 362 in an outward direction, for example, as indicated by arrow D2, thereby rotating the second section 256 of the second shaft 252 in an outward direction, for example, as indicated by arrow D2. Rotation of the second section 256 of the second shaft 252 causes the helical member 272 to travel in an outward direction on the riser member, for example, as indicated by arrow D3.

[0051] ​The movement of the helical member 270 on the first section 254 of the second shaft 252 and the movement of the helical member 272 on the second section 256 of the second shaft 252 causes the lower shell member 110 and the upper shell member 120 to move linearly relative to each other, for example, to expand at the anterior side as indicated by arrow D4.

[0052] It should be noted that, although the operation of the drive gear 314 and the translation gear 312 of the first gear assembly 310, the operation of the first drive gear 354 and the second drive gear 364 of the second gear assembly 350, the operation of the first translation gear 352 and the second translation gear 362 of the second gear assembly 350, and the operation of the first drive mechanism 200 and the operation of the second drive mechanism 250 are described in sequential steps for the sake of clarity, the rotation, translation, or movement of the above assemblies, mechanisms, or components of the mechanisms occur simultaneously while simultaneously turning the first driver 410 and the second driver 420 of the surgical instrument 400. Figure 4 The example illustrated in FIG. 6 causes the intervertebral fusion device 100 to expand at both the posterior side 104 and the anterior side 106 by simultaneously turning the first driver 410 and the second driver 420 of the surgical instrument 400, for example, in a clockwise direction. The reverse operation of turning the first driver 410 and the second driver 420 in a counterclockwise direction can cause the intervertebral fusion device 100 to collapse from the expanded configuration. Figure 7 FIG. 7 is an isometric view showing the expanded configuration of the intervertebral fusion device 100.

[0053] Example 2: lordotic mode (independent anterior shaft adjustment)

[0054] Referring to Figure 5 and Figure 1C The lordotic mode or independent anterior shaft adjustment of the example intervertebral fusion device 100 will now be described. In the lordotic mode, the second drive mechanism 250 of the intervertebral fusion device 100 can be operated independently of the first drive mechanism 100, thereby allowing lordotic adjustment of the configuration of the intervertebral fusion device 100 at the anterior side 106. The lordotic mode of the intervertebral fusion device 100 can be desired to provide an offset in expansion between the anterior side 104 and the posterior side 106 of the intervertebral fusion device 100. The anterior side 104 can expand and / or collapse to a point below the posterior side 106, thereby resulting in negative lordosis (kyphosis).

[0055] Beginning in the lordotic mode, the user can extend only the second driver 420 of the surgical instrument 400, thereby allowing only the second driver 420 to engage the first drive gear 354 of the second gear assembly 350, as shown in FIG. 8. Figure 3C If the first driver 410 of the surgical instrument 400 has been inserted across the entire span of the intervertebral fusion device during the expansion mode, the first driver 410 can be retracted to Figure 3CThe points shown in FIG. 18 can be used to only independently operate the anterior side 106 of the intervertebral fusion device 100. Indicia on the surgical instrument 400 can be provided to help indicate how far the first driver 410 can be inserted into the intervertebral fusion device 100 for an anterior lordotic mode. The user can then apply torque in a direction generally perpendicular to the second driver mechanism 250 of the intervertebral fusion device 100 by turning the second driver 420 in a clockwise direction, for example as indicated by arrow El.

[0056] Referring to Figure 5 and Figure 1C Turning of the second driver 420 of the surgical instrument 400 rotates the first drive gear 354 of the second gear assembly 350 in a clockwise direction, for example as indicated by arrow Fl, which in turn drives the first translation gear 352 in an outward direction, for example as indicated by arrow F2, causing the first section 254 of the second shaft 252 to rotate in an outward direction, for example as indicated by arrow F2. Rotation of the first section 254 of the second shaft 252 causes the helical member 270 to travel in an outward direction on the riser member, for example as indicated by arrow F3.

[0057] Turning of the second driver 420 of the surgical instrument 400 also rotates the second drive gear 364 of the second gear assembly 350 in a clockwise direction, for example as indicated by arrow Gl, which in turn drives the second translation gear 362 in an outward direction, for example as indicated by arrow G2, causing the second section 256 of the second shaft 252 to rotate in an outward direction, for example as indicated by arrow G2. Rotation of the second section 256 of the second shaft 252 causes the helical member 272 to travel in an outward direction on the riser member, for example as indicated by arrow G3. In certain embodiments, the first drive gear 354 and the second drive gear 364 can be modified, wherein there is a gap between the two components when assembled, and the first drive gear 354 has an increased overall diameter. The first drive gear female hexagon mating geometry that mates with the second driver 420 of the surgical instrument 400 can be modified to allow the second driver 420 to pass completely through the first drive gear 354 and reach the second drive gear 364. This modified design configuration will allow for unequal expansion across the coronal plane between the helical member 270 and the helical member 272, allowing for correction of patients with deformities such as scoliosis.

[0058] Movement of the helical members 270, 272 on the independent vertical member members linearly moves the first and second shell members 110, 120 relative to each other or expands the anterior side 106, thereby adjusting the intervertebral fusion device 100 for lordosis at the anterior side 106 as indicated by arrow HI. All of the previously described movements in the opposite direction to accomplish the components to create a lordotic adjustment of the point of the anterior side 106 below the posterior side 104 will adjust the intervertebral fusion device 100 for kyphosis (negative lordosis).

[0059] It should be noted that, although the operation of the first and second drive gears 354, 364 of the second gear assembly 350, and the first and second translation gears 352, 362 of the second gear assembly 350, and the operation of the second drive mechanism 250 are described in sequential steps for clarity, the above components, mechanisms or parts operate simultaneously as the second driver 420 of the surgical instrument 400 is turned. Furthermore, Figure 5 The example shown in FIG. 18 adjusts the intervertebral fusion device 100 for lordosis or expands the device at the anterior side 106 by turning the second driver 420 of the surgical instrument 400 in a clockwise direction. The intervertebral device can also operate properly if inserted into the disc space upside down or inverted. Proper operation of the intervertebral device in this inverted position can be achieved by reversing the applied torque, and by rotating the second driver 420, for example, in a counterclockwise direction, the degree of lordosis of the intervertebral fusion device 100 can be adjusted. Figure 8 FIG. 19 is an isometric view showing a lordosed configuration of the intervertebral fusion device 100.

[0060] Example 3: Lordosis Mode (Independent Posterior Shaft Adjustment)

[0061] Referring to Figure 6 and Figure 1C Another lordosis mode or independent posterior shaft adjustment of the example intervertebral fusion device 100 will now be described. In this lordosis mode, the first drive mechanism 200 of the intervertebral fusion device 100 can be operated independently of the second drive mechanism 250, thereby adjusting the configuration of the intervertebral fusion device 100 for lordosis at the posterior side 104. The posterior side 104 can expand to a point above the anterior side 106, thereby resulting in negative lordosis (kyphosis).

[0062] Beginning in the lordosis mode, the user can extend only the first driver 410 of the surgical instrument 400, thereby allowing only the first driver 410 to engage the drive gear 314 of the first gear assembly 310, as Figure 3DIn the lordotic mode, the second first driver 420 of the surgical instrument 400 does not engage the first drive gear 354 of the second gear assembly 350. The user can then apply torque in a direction generally perpendicular to the first drive mechanism 200 of the intervertebral fusion device 100 by turning the first driver 410 in a clockwise direction, for example, as indicated by arrow 11.

[0063] Referring to Figure 6 and Figure 1C , turning of the first driver 410 of the surgical instrument 400 rotates the drive gear 314 of the first gear assembly 310 in a clockwise direction, for example, as indicated by arrow Jl, which in turn drives the translation gear 312 in an outward direction, for example, as indicated by arrow J2, causing the first shaft 202 to rotate in an outward direction, for example, as indicated by arrow J2. Rotation of the first shaft 202 causes the helical members 220, 222 to travel in an outward direction on the riser members, for example, as indicated by arrow J3.

[0064] Movement of the riser members 220, 222 on the independent riser members causes the first and second shell members 110, 120 to move linearly relative to each other or expand at the posterior side 104, thereby making lordotic adjustments to the intervertebral fusion device 100 at the posterior side 104, as indicated by arrow Kl. Completion of the expansion of the adjustment node above the posterior side 104 to the anterior side 106 will make a kyphotic adjustment (negative lordosis) to the intervertebral fusion device 100.

[0065] It should be noted that, although the operation of the drive gear 314 and the translation gear 312 of the first gear assembly 310 and the operation of the first drive mechanism 20 are described in sequential steps for the sake of clarity, the rotation, translation, or movement of the above components, mechanisms, or parts occur simultaneously upon turning of the first driver 410 of the surgical instrument 400. Moreover, Figure 6 The example shown in

[0066] Figures 9A-9B An example intervertebral fusion device 100 placed in adjacent intervertebral bodies 452, 452 and expanded and / or lordotically adjusted according to an embodiment of the present disclosure is shown.

[0067] Reference will now be made to Figures 10A-14CIn some embodiments, the intervertebral fusion device 100 can include a fixation assembly 500 that can secure the intervertebral fusion device 100 in the intervertebral space to prevent unwanted lateral or medial migration of the intervertebral fusion device 100 and to prevent the intervertebral fusion device 100 from expanding or returning after adjustment.

[0068] As shown in FIG. 1, the intervertebral fusion device 100 can include a fixation assembly 500 that can secure the intervertebral fusion device 100 in the intervertebral space to prevent unwanted lateral or medial migration of the intervertebral fusion device 100 and to prevent the intervertebral fusion device 100 from expanding or returning after adjustment. Figures 10A-10B As shown, the fixation assembly 500 generally includes a plate assembly 510 and fasteners 512. The plate assembly 510 is configured to be attachable to the intervertebral fusion device 100. The plate assembly 510 includes a plate member 511 provided with apertures 514 configured for insertion of the fasteners 512 into the apertures 514 for securement to the inferior and superior vertebral bodies, respectively. The plate assembly 510 can also include fastener locking mechanisms 520 to prevent withdrawal of the fasteners from the vertebral bodies. While four apertures 514 in the plate member 511 and four fasteners 512 are shown, other embodiments can include fewer or more than four apertures 514 in the plate member 511. Likewise, while four fastener locking mechanisms 520 are shown, other embodiments can include fewer or more than four fastener locking mechanisms. In addition, Figure 10B An assembly view of the plate assembly 510 attached to the intervertebral fusion device 100 is depicted. It should be noted that, in use, the plate assembly 510 can be attached to the intervertebral fusion device 100 in situ or after the intervertebral fusion device 100 has been inserted into the patient and placed between adjacent vertebral bodies. Figures 14A-14B Attachment of the plate assembly 510 to the intervertebral fusion device 100 after the intervertebral fusion device 100 has been placed, expanded, and / or lordotically adjusted to the appropriate configuration between adjacent vertebrae is shown. The plate assembly 510 can also be attached to the intervertebral fusion device 100 prior to implantation of the intervertebral fusion device, if desired.

[0069] In some embodiments, the plate member 511 can be constructed of a material having sufficient strength, such as titanium, stainless steel, or other metals or alloys, to provide orthopedic support or supplemental fixation in addition to preventing migration or expansion of the intervertebral fusion device 100. As used herein, the term "supplemental fixation" refers to embodiments of fixation plates that function as orthopedic devices that can hold adjacent vertebrae in place or immobilize adjacent vertebrae prior to performing arthrodesis (bone fusion).

[0070] Referring to FIG. 2, the plate assembly 510 is shown attached to the intervertebral fusion device 100. The plate assembly 510 is shown attached to the intervertebral fusion device 100 in a position that is medial to the intervertebral fusion device 100. The plate assembly 510 can be attached to the intervertebral fusion device 100 in other positions, such as lateral to the intervertebral fusion device 100. Figure 11The plate member 511 can generally be H-beam shaped or bone shaped with cutouts in the sides to minimize or reduce the profile of the plate. For example, the plate member 511 can have a reduced size in the middle portion compared to the upper and lower portions of the plate member 511. Apertures 514 can be provided in the upper and lower portions of the plate member 511. The reduced or optimized profile of the plate assembly 510 allows for improved visualization of the intervertebral fusion device 100 in the patient, especially in the anterior view, for example. The reduced profile of the plate assembly 510 also facilitates insertion and placement of the plate assembly 510 in the patient anatomy. Other suitable sizes and shapes of the fixation plate are possible and the present claims are not limited in this regard. The plate member 511 can include a geometric feature 516, such as a ring-shaped geometric feature provided with threads for connection with surgical instruments.

[0071] Referring to Figure 11 The locations of the apertures 514 in the plate member 511 can be spaced apart as shown to allow insertion of the fasteners 512 through and directed to the inferior and superior vertebral bodies, respectively. The apertures 514 in the plate member 511 can be inclined, for example, at 0 to 15 degrees with respect to a reference plane perpendicular to the surface of the plate member 511. As better observed in Figure 10B The inclined apertures allow for an inclined trajectory of the fasteners inserted through the apertures, providing the fasteners with an optimal angle of anchoring to the vertebral bodies. In addition, the plate member 511 can have a curved or non-parallel profile geometry present at the location of the apertures in relation to the middle body portion to allow for a further inclined trajectory of the fasteners of more than 15 degrees for optimal cortical bone. The apertures 514 can include a counterbore or a recessed portion configured to receive the head of the fastener 512. The head of the fastener 512 can have a spherical shape as shown in Figure 10A or any other suitable shape such as a tapered or cylindrical shape to facilitate or allow for fastener trajectory adjustment. Examples of fasteners include, but are not limited to, a spinal expanding head screw, a spinal locking screw, a spinal self-locking screw, a spinal shaft screw, a spinal nail, a spinal barb, a spinal hook, or other threaded or non-threaded member that can anchor to the vertebral body.

[0072] Referring to Figure 11 The plate assembly 510 can include at least one fastener locking mechanism 520 configured to prevent the fastener from backing out. In Figure 11In the illustrated embodiment, four fastener locking mechanisms 520 are provided, each positioned adjacent to an orifice 514 in the plate member 511. An example fastener locking mechanism 520 can include a locking rod 522 received in a recess 524 adjacent to the orifice 514 in the plate member 511, and an adapter 526 welded or attached to an end of the locking rod 522 to retain the locking rod 522 in the recess 524 and allow the locking rod 522 to rotate. The head of the locking rod 522 can have a rounded side portion 522a, a flat side portion 522b, and an end 522c provided with a feature such as a female hex to receive a driver for engaging the locking mechanism 520. When the locking rod 522 is rotated to set the locking mechanism 520 in an unlocked or open state, the head flat side portion 522b faces the orifice 514 in the plate member 511, thereby opening the orifice 514 to allow insertion of a fastener 512 therethrough. After the fastener 512 is fully driven into the vertebral body and the fastener head is received in the counterbore of the orifice, the locking rod 522 can be rotated to set the locking mechanism 520 in a locked state in which the head rounded side portion 522a extends over at least a portion of the orifice 514 or over the fastener 512, thereby preventing the fastener 512 from backing out. The locking mechanisms 520 of the present disclosure allow for a quick "one-step" locking, such that only one rotation of the locking rod 522 by the driver is needed to lock or unlock the fastener 512. The use of a "one-step" locking mechanism can also simplify or reduce the profile of the plate assembly 510, which is beneficial for insertion and placement of the device in the patient anatomy.

[0073] Referring to Figures 12A-12B and Figures 13A-13B The plate assembly 510 can include one or more geometric features configured for attachment to the intervertebral fusion device 100. The plate assembly 510 can include a male geometric feature extending from the plate member configured to be inserted into a female geometric feature in the drive gear of the first and / or second gear assemblies 310, 350. Figures 12A-12B The plate assembly 510 is shown including a male geometric feature 530, such as a male hex, configured to mate with a female hex 355 in the first drive gear 354 of the second gear assembly 350. Once the plate assembly 510 is inserted into the intervertebral fusion device 100 and secured to the vertebral bodies, the male hex 530 of the plate assembly 510 can prevent unwanted rotation of the first drive gear 354 of the second gear assembly 350, thereby serving as an auxiliary lock to prevent unwinding or returning after adjustment of the intervertebral fusion device 100. Figures 13A-13BA plate assembly 510 is shown that includes an elongated male geometry 532, e.g., a male sextant, configured to pass through the first and second drive gears 354, 364 of the second gear assembly 350 and to mate into a female sextant 324 in the drive gear 314 of the first gear assembly 310. Once the plate assembly 510 is inserted into the interbody fusion device 100 and secured to the vertebral bodies, the elongated male sextant 532 prevents unwanted rotation of the drive gear 314 of the first gear assembly 310, thereby functioning as an auxiliary lock to prevent unwinding or returning after the interbody fusion device 100 is adjusted. In certain embodiments of the present disclosure, the plate assembly 510 can include a first male geometry configured to mate into a female geometry in the drive gear 314 of the first gear assembly 310 and a second male geometry configured to mate into a female geometry in the first drive gear 354 of the second gear assembly 350. For example, as shown in FIGS. 5A-5C, the plate assembly 510 can include a first male sextant 532, e.g., an elongated male sextant configured to mate into a female sextant 324 in the drive gear 314 of the first gear assembly 310, and a second male sextant 530 configured to mate into a female sextant 355 in the first drive gear 354 of the second gear assembly 350. Figure 13B As shown in FIGS. 5A-5C, the plate assembly 510 can include a first male sextant 532, e.g., an elongated male sextant configured to mate into a female sextant 324 in the drive gear 314 of the first gear assembly 310, and a second male sextant 530 configured to mate into a female sextant 355 in the first drive gear 354 of the second gear assembly 350.

[0074] U.S. Application Serial No., titled“Dual Axis Adjustable Spinal Systems and Interbody Fusion Devices with Fixation,” filed concurrently herewith, which describes various embodiments of fixation assemblies for interbody fusion devices and spinal systems, the entire disclosure of which is incorporated by reference herein in its entirety.

[0075] Referring to Figures 14A-14C In use, the plate assembly 510 can be inserted and attached to the interbody fusion device 100 in situ. For example, the interbody fusion device 100 in a collapsed configuration can first be inserted and placed between adjacent vertebrae 452, 454 via an anterior lumbar interbody fusion (ALIF) procedure or any other suitable surgical procedure. The interbody fusion device 100 can be expanded and / or lordotically adjusted using the surgical instrument 400, thereby forming a suitable configuration between the adjacent vertebrae 452, 454, as described above in connection with FIGS. 3-4. Figure 6

[0076] ​The plate assembly 510 can then be introduced to the target area via the same surgical method used to insert and place the intervertebral fusion device 100 and attached to the intervertebral fusion device 100. According to embodiments of the present disclosure, the surgical instrument 400 used to place and operate the intervertebral fusion device 100 can be used to insert and attach the plate assembly 510. For example, a surgeon can connect the plate assembly 510 to the surgical instrument 400 via threads on the annular geometric feature 516 in the plate member 511, introduce the plate assembly 510 to the target area via the same surgical method, and insert the plate assembly 510 into the intervertebral fusion device 100 as shown in Figure 14A .

[0077] The fasteners 512, e.g., spinal screws, can then be inserted through the apertures 514 in the plate member 511 and screwed into the inferior 452 and superior 454 vertebral bodies, respectively. Once the fasteners 512 are driven all the way, the fastener locking mechanism 520 of the plate assembly 510 can be actuated using the surgical instrument 400 to lock the fasteners 512 to prevent the fasteners 512 from backing out as shown in Figure 14B . Undesirable lateral or medial migration and deployment or return of the intervertebral fusion device 100 after expansion or lordotic adjustment can then be prevented as shown in Figure 14C .

[0078] In conjunction with Figures 1A-14C Embodiments of an intervertebral fusion device are described. Advantageously, embodiments of the intervertebral fusion device of the present disclosure allow a surgeon to apply torque from anterior to perpendicular, which is then converted to torque for the drive mechanism responsible for expansion and lordotic adjustment of the intervertebral fusion device. The dual axis drive mechanism allows the surgeon to adjust the height and unique horizontal of lordosis to achieve full anatomical individualization of the patient. For example, embodiments of the intervertebral fusion device of the present disclosure allow a surgeon to set the intervertebral fusion device to a fine configuration to any unique height (e.g., 11.6 mm) and / or unique angle (e.g., 21.7°) required for the patient's spinal balance profile. Conventional techniques can have implants built in only a few predetermined lordotic configuration such as 20°, 25°, 30°.

[0079] The intervertebral fusion device can provide improved surgical efficiency. Conventionally, a surgeon must effectively trial or size an implant to determine the implant size required for a particular patient. According to embodiments of the present disclosure, the intervertebral fusion device can start at a small collapsed height and then increase in height. This allows for a simplified or greatly reduced trial process, which in turn can reduce the brunt of the effects associated with the trial process. The mechanism of the implant also has enough room for the vertebral bodies to disperse back to their normal desired position. This dispersion control also eliminates the need to use additional instruments for dispersion.

[0080] The use of the fixation assembly prevents undesirable lateral or medial migration and expansion or return of the intervertebral fusion device after expansion or lordotic adjustment. The fixation plate can be configured to have sufficient strength to provide orthopedic support or supplemental fixation. The fixation plate is implantable and can be configured to attach to the intervertebral fusion device via a single surgical procedure and patient position, thereby minimizing disruption to the patient's anatomy. The geometry, such as the male geometry, in the fixation plate can serve as an auxiliary safety lock for the intervertebral fusion device, preventing the intervertebral fusion device from expanding or returning after adjustment.

[0081] The intervertebral fusion device also provides benefits related to manufacturing and hospital administration. The intervertebral fusion device can reduce inventory. Currently, an implant size must exist for each height with increments typically in the order of 1 mm and lordotic increments of 5 degrees. This quickly makes the number of implants needed on hand very large. The intervertebral fusion device according to embodiments of the present disclosure is fully adjustable, which ultimately reduces the number of implants needed in the operating room or needed to be stored in inventory.

[0082] Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art. The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The term "or" means "and / or" unless the context clearly dictates otherwise. The terms "first," "second," and "third" are used to differentiate between similar elements, and should not be construed in any particular order unless the context clearly dictates otherwise.

[0083] Those skilled in the art will appreciate that various other modifications can be made. All such or other variations and modifications are contemplated as being within the scope of the present disclosure.

Claims

1. An intervertebral fusion device comprising: a housing including a first housing member and a second housing member; a drive mechanism operable to expand and / or contract the housing, the drive mechanism including a shaft having a longitudinal axis; a gear assembly operable to transmit torque to the drive mechanism, the gear assembly including a first translating gear and a first drive gear, the first translating gear being coupled to the shaft, the first drive gear being configured to receive torque applied from a direction generally perpendicular to the longitudinal axis of the shaft and to drive the first translating gear, whereby application of torque to the first drive gear causes the first translating gear and the shaft to rotate about the longitudinal axis, thereby actuating the drive mechanism to effect expansion and / or contraction of the housing, wherein the drive mechanism further includes a first helical member and a second helical member, each of the first and second helical members having a through opening adapted to allow passage of the shaft; at least the first housing member includes a plurality of riser members for receiving the first and second helical members; the shaft is engageable with the first and second helical members, whereby rotation of the shaft about the longitudinal axis causes the first and second helical members to rotate with the shaft and travel along the shaft; and the first and second helical members are engageable with the plurality of riser members, whereby rotation of the first and second helical members causes the first and second housing members to move relative to one another to effect expansion and / or contraction of the housing.

2. The intervertebral fusion device of claim 1 wherein, the first helical member is disposed at a first lateral side of the first translating gear, the second helical member is disposed at a second lateral side of the first translating gear, and the first and second helical members are configured to travel in opposite directions upon rotation of the shaft.

3. The intervertebral fusion device of claim 1, wherein the shaft includes a first section and a second section, the first and second sections of the shaft being rotatably connected to a connecting member, the first translating gear being coupled to the first section of the shaft, and the gear assembly further includes a second translating gear and a second drive gear, the second translating gear being coupled to the second section of the shaft, the second drive gear being configured to receive torque applied from a direction non-parallel to the longitudinal axis of the shaft and to drive the second translating gear, whereby application of torque to the second drive gear causes the second translating gear and the second section of the shaft to rotate about the longitudinal axis.

4. The intervertebral fusion device of claim 3, wherein, the first and second drive gears of the gear assembly are configured to receive torque applied from a direction generally perpendicular to the longitudinal axis of the shaft.

5. The intervertebral fusion device as recited in claim 3, wherein, the first drive gear has a first pitch, and the second drive gear has a second pitch different from the first pitch.

6. The intervertebral fusion device as recited in claim 3, wherein, the first and second drive gears are connected via a tubular section and operate as a single unit.

7. The intervertebral fusion device as recited in claim 6, wherein, The connection member connecting the first and second sections of the shaft includes a ring structure configured to receive the tubular section and allow rotation of the first and second drive gears.

8. The intervertebral fusion device of claim 3, wherein, The drive mechanism further includes a first helical member having a through opening adapted to allow passage of the first section of the shaft and a second helical member having a through opening adapted to allow passage of the second section of the shaft; At least the first shell member includes a plurality of riser members for receiving the first and second helical members; The first section of the shaft is engageable with the first helical member, whereby rotation of the first section of the shaft about the longitudinal axis causes the first helical member to rotate with and travel along the first section of the shaft, and the second section of the shaft is engageable with the second helical member, whereby rotation of the second section of the shaft about the longitudinal axis causes the second helical member to rotate with and travel along the second section of the shaft; and The first and second helical members are engageable with the plurality of riser members, whereby rotation of the first and second helical members causes the first and second shell members to move relative to one another to effect expansion and / or contraction of the housing.

9. An intervertebral fusion device, comprising: a housing including a first shell member and a second shell member; first and second drive mechanisms, the first drive mechanism disposed in the housing at a first lateral region, the second drive mechanism disposed in the housing at a second lateral region, the first drive mechanism including a first shaft having a longitudinal axis, and the second drive mechanism including a second shaft having a longitudinal axis; a first gear assembly operable to transmit torque to the first drive mechanism, the first gear assembly including a translation gear coupled to the first shaft and a drive gear configured to receive torque applied from a direction that is not parallel to the longitudinal axis of the first shaft and drive the translation gear, whereby application of torque to the drive gear causes the translation gear and the first shaft to rotate about the longitudinal axis of the first shaft, thereby actuating the first drive mechanism to effect expansion and / or contraction of the housing at the first lateral region; and a second gear assembly operable to transmit torque to the second drive mechanism, the second gear assembly including a translation gear coupled to the second shaft and a drive gear configured to receive torque applied from a direction that is not parallel to the longitudinal axis of the second shaft and drive the translation gear, whereby application of torque to the drive gear causes the translation gear and the second shaft to rotate about the longitudinal axis of the second shaft, thereby actuating the second drive mechanism to effect expansion and / or contraction of the housing at the second lateral region. a second gear assembly operable to transmit torque to the second drive mechanism, the second gear assembly including at least a first translation gear coupled to the second shaft and a first drive gear configured to receive torque applied from a direction that is not parallel to a longitudinal axis of the second shaft and to drive the first translation gear, whereby application of torque to the first drive gear causes the first translation gear and the second shaft to rotate about the longitudinal axis of the second shaft, thereby actuating the second drive mechanism to effect expansion and / or contraction of the housing at the second lateral region.

10. The intervertebral fusion device of claim 9, wherein, the drive gear of the first gear assembly is configured to receive torque applied from a direction that is substantially perpendicular to a longitudinal axis of the first shaft, and the first drive gear of the second gear assembly is configured to receive torque applied from a direction that is substantially perpendicular to a longitudinal axis of the second shaft.

11. The intervertebral fusion device as recited in claim 9, wherein, the first gear assembly and the second gear assembly are simultaneously operable, whereby the degree of expansion and / or contraction of the housing at the first lateral region and the degree of expansion and / or contraction of the housing at the second lateral region can be simultaneously adjusted.

12. The intervertebral fusion device of claim 9, wherein: the first gear assembly is independently operable from the second gear assembly, whereby the degree of expansion and / or contraction of the housing at the first lateral region can be independently adjusted, and / or the second gear assembly is independently operable from the first gear assembly, whereby the degree of expansion and / or contraction of the housing at the second lateral region can be independently adjusted.

13. The intervertebral fusion device of claim 9, wherein: the second shaft includes first and second sections each rotatably connected to a connecting member, the first translation gear of the second gear assembly being coupled to the first section; the second gear assembly further includes a second translation gear coupled to the second section and a second drive gear configured to receive torque applied from a direction that is not parallel to a longitudinal axis of the second shaft and to drive the second translation gear, whereby application of torque to the second drive gear causes the second translation gear and the second section of the second shaft to rotate about the longitudinal axis of the second shaft.

14. The intervertebral fusion device as recited in claim 13, wherein, the first and second drive gears of the second gear assembly are operable as a single unit.

15. The intervertebral fusion device of claim 14, wherein: the first and second drive gears of the second gear assembly are coupled to form a tubular section; and the connecting member rotatably connecting the first and second sections of the second shaft includes a ring structure configured to receive the tubular section, thereby allowing the first and second drive gears to rotate.

16. The intervertebral fusion device of claim 14, wherein: the drive gear of the first gear assembly includes an elongated portion, the second drive gear of the second gear assembly includes a sleeve section, the elongated portion of the drive gear of the first gear assembly is rotatably received in the sleeve section of the second drive gear of the second gear assembly, and the elongated portion of the drive gear of the first gear assembly includes an end having a feature for engagement with a first driver of a surgical instrument, and the first drive gear of the second gear assembly includes a feature for engagement with a second driver in the surgical instrument, thereby allowing the surgical instrument to operate the first gear assembly and the second gear assembly simultaneously, or the first gear assembly independently of the second gear assembly, or the second gear assembly independently of the first gear assembly.

17. The intervertebral fusion device of Claim 13, wherein: the first drive mechanism includes first and second helical members, the first and second helical members of the first drive mechanism each having a through opening adapted to allow passage of the first shaft; the second drive mechanism includes first and second helical members, the first helical member of the second drive mechanism having a through opening adapted to allow passage of the first section of the second shaft, the second helical member of the second drive mechanism having a through opening adapted to allow passage of the second section of the second shaft; at least the first shell member includes a plurality of riser members for receiving the first and second helical members of the first drive mechanism and the first and second helical members of the second drive mechanism; the first shaft of the first drive mechanism is engageable with the first and second helical members of the first drive mechanism, whereby rotation of the first shaft of the first drive mechanism causes the first and second helical members of the first drive mechanism to rotate with and travel along the first shaft of the first drive mechanism, thereby moving the first and second shell members relative to one another to effect expansion and / or contraction of the shell at the first lateral region; and the first section of the second shaft is engageable with the first helical member of the second drive mechanism, the second section of the second shaft is engageable with the second helical member of the second drive mechanism, whereby rotation of the first and second sections of the second shaft causes the first and second helical members of the second drive mechanism to rotate with and travel along the first and second sections of the second shaft, respectively, thereby moving the first and second shell members relative to one another to effect expansion and / or contraction of the shell at the second lateral region.

18. The intervertebral fusion device of Claim 9, further comprising: a first thrust bearing coupling the first and second shafts at the first ends of the first and second shafts; a second thrust bearing coupling the first shaft and the second shaft at second ends of the first shaft and the second shaft, wherein the first and second thrust bearings are configured to allow rotation of the first and second shafts about longitudinal axes of the first and second shafts, respectively, and to prevent translational movement of the first and second shafts, respectively.

19. The intervertebral fusion device as recited in claim 9, further comprising a fixation assembly for securing the intervertebral fusion device in adjacent vertebral bodies, the fixation assembly comprising a plate assembly, at least one first fastener, and at least one second fastener, wherein, the plate assembly is configured to be attachable to the intervertebral fusion device and comprises a plate member provided with at least one first aperture for insertion of the at least one first fastener therethrough into a first vertebral body and at least one second aperture for insertion of the at least one second fastener therethrough into a second vertebral body, thereby allowing the plate assembly to be attached in situ to the intervertebral fusion device and secured to the first and second vertebral bodies.

20. The intervertebral fusion device as recited in claim 19, wherein, the plate assembly comprises a first geometric feature configured to cooperate with a geometric feature in a drive gear of the first gear assembly to prevent rotation of the drive gear of the first gear assembly relative to the fixation plate.

21. The intervertebral fusion device as recited in claim 20, wherein, the plate assembly further comprises a second geometric feature configured to cooperate with a geometric feature in a first drive gear of the second gear assembly to prevent rotation of the first drive gear of the second gear assembly relative to the fixation plate.

22. The intervertebral fusion device as recited in claim 21, wherein, the plate assembly is constructed of a material having a strength capable of providing supplemental fixation of the first and second vertebral bodies.

23. The intervertebral fusion device as recited in claim 21, wherein, the plate assembly comprises a first fastener locking mechanism configured to prevent withdrawal of the at least one first fastener from at least one of the first apertures and a second fastener locking mechanism configured to prevent withdrawal of the at least one second fastener from the second apertures.

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