Patent Application
20230172724
The disclosures made herein relate generally to interbody implant devices adapted for facilitating repair of ailments to bony structures in a living body and, more particularly, to expandable spinal interbody implant devices.
The spinal column of humans and other species of the subphylum vertebrata is a complex structure comprised of multiple soft connective tissues and bony connective tissues well known to be subject to structural ailment. Involved in numerous functions, the spinal column provides structural support to the body, allows for functional movement of the body, and protection of delicate parts of the neurological system including the spinal cord and nerve roots. Body weight and biomechanical forces are transferred through the spinal column during most functional activities of life. Numerous complex structures constituting the spinal column permit for transfer of forces to the body in a fashion that allows motion in all three geometric planes (sagittal, coronal, axial) while simultaneously achieving the aforementioned functions.
The spinal column includes a plurality of bony vertebrae, cartilaginous intervertebral discs, and ligaments that provide for interconnection of and spacing between the segments of the spinal column. Each intervertebral disc includes a cartilaginous anulus fibrosus and nucleus pulposus. All vertebral endplates (i.e., the endplates) are each affixed to one of twenty three intervertebral discs from the inferior endplate of the second cervical vertebrae to the superior endplate of the first sacral vertebrae. Normal intervertebral discs exhibit sufficient properties (e.g., mass, density, resiliency, etc.) for providing spatial positioning and a cushioning effect between adjacent vertebrae. Thus, in a healthy spinal column, spatial positioning of and cushioning between adjacent vertebrae are maintained through such interconnection of the vertebrae by the intervertebral discs. In the lumbar region, the shape of healthy intervertebral discs are important to the overall sagittal alignment and balance of the spinal column.
It is well-known that functionality of one or more of the intervertebral discs can fully or partially fail. Causes of intervertebral disc failure may include but are not limited to degenerative, traumatic, infectious, oncologic, or congenital etiologies. Failure of intervertebral discs may result in loss of spinal column structural integrity. A loss of normal spinal column spatial geometry such as intervertebral height, intervertebral slippage, or intervertebral malalignment may result as a consequence of intervertebral disc failure. Intervertebral disc failure may also result in the loss of mechanical cushioning between vertebral segments. The consequences of intervertebral disc failure may lead to a person developing pain, numbness, weakness, or loss of neurologic functions.
Spinal implants intended to address ailments arising from failure of intervertebral disc functionality are well known in the art. Expandable interbody implant devices (sometimes referred to as expandable cages) are one particular type of such spinal implants. Expandable interbody implant devices are configured to replace or augment an intervertebral disc and provide for at least its associated intersegmental/intervertebral positioning functionality. An expandable interbody implant device is retained in fixed relationship to the adjacent vertebrae by mechanical and/or biological means. Interbody implant devices are also often configured to have or enable restoration of appropriate intervertebral endplate angles, i.e. the lordotic/kyphotic angle. The expandability of such implants allows placement thereof into a corresponding surgically-enhanced disc space between two adjacent vertebrae and, thereafter, be selectively expanded to achieve restoration or enhancement of intervertebral spacing and intervertebral angle.
When utilizing an expandable interbody device, it is generally highly desirable to provide for biological interconnection between the adjacent vertebrae for the purpose of promoting fusion of the adjacent vertebrae (i.e., such a device sometimes referred to as an expandable interbody fusion device). To this end, it is desirable to introduce a graft material between spaced-apart endplate surfaces of the adjacent vertebrae and it is desirable for the expandable interbody device to include a graft passage extending therethrough within which a portion of the graft material can reside and through which connective bony tissue can ultimately grow and join the vertebral bone directly above the expandable interbody device to the vertebral bone directly below the expandable interbody device. Any physical element of the expandable interbody device residing within the graft passage are obstructions that limit the available volume of graft material that may be contained therein and that correspondingly limits the amount of bone tissue that may ultimately grow therein. Any physical element of the expandable interbody device residing within the graft passage are obstructions that limit the direct pathway thru which bone tissue can grow across. Thus, such obstructions within the graft window are counterproductive and undesirable to the objective of vertebral interbody fusion.
Therefore, an implantable device configured for use in repairing an ailment in a bony structure of a living body (e.g., an expandable interbody implant device configured for use in repairing an ailment in a person's spinal column) that does not have elements thereof residing within the graft passage thereof is advantageous, desirable and useful.
Embodiments of the disclosures made herein are directed to expandable interbody implant devices having an unobstructed graft passage. Specifically, an expandable interbody implant device configured in accordance with embodiments of the disclosures made herein has a structure in which an entire space of the graft passage is devoid of elements thereof that enable adjustment of the expandable interbody implant device between a collapsed configuration and displaced configurations (e.g., an expanded configuration and/or a tilted configuration). In this manner, expandable interbody implant devices configured in accordance with embodiments of the disclosures made herein do not have obstructions within the graft passage thereof that limit the available volume of graft material and associated bone tissue or other soft tissue that may grow within the graft passage.
In one or more embodiments, an implant device comprises endplates and endplate movement mechanisms. The endplates are engaged with each other for enabling movement of the endplates to a collapsed configuration and to displaced configurations. The endplates jointly define a graft passage when the endplates are in the collapsed configuration. The graft passage is at least partially encompassed by a plurality of graft passage sidewalls each extending from a perimeter edge portion of a graft material containment space of a respective one of the endplates. The endplate movement mechanisms are each located entirely external to the graft passage and operably coupled to each of the endplates to enable adjustment of the endplates to the collapsed configuration and to the displaced configurations.
In one or more embodiments, an implant device comprises first and second endplates and spaced apart endplate movement mechanisms. The first and second endplates are engaged with each other for enabling movement of the endplates to a collapsed configuration, expanded configurations and tilted configurations. The endplates jointly define a graft material containment space when the endplates are in the collapsed configuration. The graft material containment space is at least partially encompassed by graft passage sidewalls extending from a perimeter edge portion of a graft window of at least one of the endplates. The endplate movement mechanisms each residing entirely in an interior space of the spinal implant external to the graft material containment space. Each of the endplate movement mechanisms is operably coupled to each of the endplates to enable adjustment of the endplates to the collapsed configuration, the expanded configurations and the tilted configurations.
In one or more embodiments, a spinal segment restoration device comprises first and second vertebrae support platforms and first and second movement mechanisms. The first and second vertebrae support platforms are engaged with each other for enabling movement of the vertebrae support platforms to a collapsed configuration, expanded configurations and tilted configurations. The vertebrae support platforms jointly define a graft passage when the vertebrae support platforms are in the collapsed configuration. The graft passage is at least partially bound by a plurality of graft passage sidewalls each extending from a perimeter edge portion of a graft window of a respective one of the vertebrae support platforms. The first and second movement mechanisms each residing entirely external to the graft passage. Each of the movement mechanisms is operably coupled to each of the vertebrae support platforms to enable adjustment of the vertebrae support platforms to the collapsed configuration, the expanded configurations and the tilted configurations.
In one or more embodiments, a translating linkage member of a first one of the endplate movement mechanisms is spaced away from a translating linkage member of a second one of the endplate movement mechanisms and the graft passage is positioned between the first and second ones of the endplate movement mechanisms.
In one or more embodiments, the translating linkage member of each of the endplate movement mechanisms includes first spaced-apart engagement members each translatably engaged with a respective elongated space within the first one of the endplates and second spaced-apart engagement members each translatably engaged with a respective elongated space within the second one of the endplates;
In one or more embodiments, the respective elongated space within the first one of the endplates extends generally parallel with a longitudinal centerline axis of the spinal implant device and the respective elongated space within the second one of the endplates extends in a skewed manner with respect to the longitudinal centerline axis of the spinal implant device.
In one or more embodiments, each of the endplate movement mechanisms reside entirely in a respective portion of an interior space of the spinal implant that is external to the graft material containment space.
In one or more embodiments, the graft material containment space is a graft passage.
In one or more embodiments, the interior space is at least partially encompassed by a plurality of graft passage sidewalls extending from a perimeter edge portion of a graft window of at least one respective one of the endplates.
In one or more embodiments, the interior space is at least partially encompassed by a plurality of graft passage sidewalls extending from a perimeter edge portion of a graft window of at least one respective one of the endplates.
In one or more embodiments, the graft passage sidewalls of at least one of the endplates extend contiguously around the graft passage.
In one or more embodiments, each of the endplates includes an anterior structural leg, a posterior structural leg and transverse structural legs coupled therebetween; the anterior structural leg and the posterior structural leg extend generally parallel to each other; the transverse structural legs are spaced part from each other; a first one of the endplate movement mechanisms extends at least partially along a length of a portion of the interior space partially defined by the anterior structural legs; and a second one of the endplate movement mechanisms extends along a length of a portion of the interior space partially defined by the posterior structural legs.
These and other objects, embodiments, advantages and/or distinctions of the present invention will become readily apparent upon further review of the following specification, associated drawings and appended claims.
Referring now to the
The implant device 100 includes a first endplate 102 and a second endplate 104 that each serve as a respective vertebrae support platform. The endplates 102, 104 are engaged with each other for enabling movement of the endplates 102, 104 to a collapsed configuration C (
As best shown in
In one or more embodiments, the graft passage sidewalls 110A, 110B of at least one of the endplates 102, 104 extend contiguously around the graft material containment space S. For example, as shown, the graft passage sidewalls 110B of the second endplate 104 extend contiguously around the graft material containment space S as well as the graft passage sidewalls 110A, 110B of the first and second endplates 102, 104 jointly extending contiguously around the graft material containment space S.
As best shown in
The implant device 100 includes a first endplate movement mechanism 112A and a second endplate movement mechanism 112B. The first and second endplate movement mechanisms 112A, 112B are laterally spaced-apart from each other. The graft material containment space S is positioned between the first and second endplate movement mechanisms 112A, 112B. As discussed below in greater detail and as is clearly shown in the drawing figures, each of the endplate movement mechanisms 112A, 112B advantageously residing entirely in an interior space of the implant device 100 that is external to the graft material containment space S. In this manner, when the implant device 100 is in (and sufficiently near) the collapsed configuration C, no part of the endplate movement mechanisms 112A, 112B reside within the graft material containment space S and the graft material containment space S is free of any other obstruction that would otherwise limit the available volume of graft material and associated bony material growth that may form within the graft material containment space S.
As best shown in
The first engagement members 118A, 118B and the elongated slot 122A, 122B of the first endplate 102 jointly define an interface structure adapted for constraining displacement of each of the translating linkage member 116 to be substantially parallel with the longitudinal centerline axis L of the implant device 100. The second engagement members 120A, 120B and the elongated slot 124A, 124B of the second endplate 104 jointly define an interface structure adapted for constraining displacement of the respective portion of the second endplate 104 to be vertical with respect to the first endplate 102 in response to axial translation of the respective one of the translating linkage members 116. In view of the disclosures made herein, a skilled person will understand that the structural association of the engagement members 118A, 118B and the elongated slot 122A, 122B of the first endplate 102 may be reversed (i.e., each integral with the opposite structural element) and that the structural association of the engagement members 120A, 120B and the elongated slot 124A, 124B of the second endplate 104 may be reversed (i.e., each integral with the opposite structural element). Furthermore, in view of the disclosures made herein, a skilled person will appreciate other structural arrangements to be used in place of the endplate movement mechanisms 112A, 112B and mating structures of the endplates 102, 104.
The adjuster 114 of each of the endplate movement mechanisms 112A, 112B includes a shank portion 114A and a head portion 114 B fixedly attached to the shank portion 114A. In one or more or more embodiments, the adjuster 114 is a threaded fastener such as, for example, a screw. The shank portion 114A of an adjuster 114 is interlockedly engaged (e.g., threadedly) with receptacle portion 126 of a respective one of the translating linkage members 116. The head portion 114B is affixed to the first endplate 102 by spaced-apart retention members 127 (e.g., pins) that are coupled to the first endplate 102 and that engage a mating feature 128 (e.g., groove) of the head portion 114B for enabling rotation of the adjuster 114 relative to the first endplate 102 but inhibiting its unrestricted axial displacement thereto.
Referring to
For example, rotation of the adjustor 114 adjacent to the first edge portion 102A, 104A of the first and second endplates 102, 104 causes a corresponding vertical displacement V of the first edge portion 104A of the second endplate 104 with respect to the first edge portion 102A of the first endplate 102 and rotation of the adjustor 114 adjacent to the second edge portion 102B, 104B of the first and second endplates 102, 104 causes a corresponding vertical displacement V of the second edge portion 104B of the second endplate 104 with respect to the second edge portion 102B of the first endplate 102. Thus, the first and second edge portions 104A, 104B of the second endplate 104 may be independently adjusted with respect to the respective adjacent one of the edge portions 102A, 102B of the first endplate 102. Direction of rotation of the adjustor 114 dictates direction of the vertical displacement. Through such adjustment of the adjustors 114, the first and second endplates 102, 104 can be selectively mobilized to the collapsed configuration, expanded configuration and tilted configuration. Selective adjustment of one or both of the endplate movement mechanisms 112A, 112B enables selective adjustment of the endplates 102, 104 from the collapsed configuration C to a displaced configuration (i.e., expanded and/or tilted) for providing restoration of adjacent bony structures (e.g., vertebrae). In the tilted configuration, the first and second edge portions 104A, 104B of the second endplate 104 may be independently adjusted with respect to the respective adjacent one of the edge portions 102A, 102B of the first endplate 102.
Referring to
In view of the disclosures made herein, a skilled person will appreciate the advantageous and beneficial aspect of the structure enabling movement of the endplates. Specifically, endplate movement mechanisms in accordance with one or more embodiments of the disclosure made herein enabling endplate expansion and retraction functionality in a manner whereby retraction does not require external compressive loading being exerted on the first and second endplates. For example, operable coupling of the endplates 102 and 104 and endplate movement mechanisms 112A, 112B of the implant device 100 are implemented in a “pinned manner ” by virtue of the engagement members 118A, 118B, of each endplate movement mechanism 112A, 112B each being captured within a mating one of the elongated slots 122A, 122B of the first endplate 102 and the engagement members 120A, 120B of each endplate movement mechanism 112A, 112B each being captured within a mating one of the elongated slot 124A, 124B of the second endplate 104. Accordingly, actuation of either of the endplate movement mechanisms 112A, 112B for expansion or retraction causes a corresponding relative movement of the second endplate 104 relative to the first endplate 102 irrespective of external compressive loading of the endplates 102, 104 via opposing engaged vertebrae engaged therewith. Such operability is advantageous as it cannot be presumed that the endplates 102, 104 will be under external compressive loading via opposing engaged vertebrae.
As shown in
In one or more embodiments, an implant device in accordance with the disclosures made herein may be a lumbar spinal interbody fusion device designed to be used in the lumbar 2/3, lumbar 3/4, lumbar 4/5, and Lumbar 5/Sacrum 1 interbody spaces. Such a device facilitates fusion of the interbody space at the aforementioned levels. This device facilitates placement into the aforementioned lumbar interbody spaces with less traumatic vertebral body impulse forces than currently available interbody fusion devices. This device is inserted into the lumbar interbody space in a collapsed configuration (e.g., fully or partially collapsed) and is capable of in-vivo expansion after such placement into the interbody space. Contact surfaces of this device are capable of expanding in a parallel or a variable angle fashion to facilitate restoration of spinal segmental anatomic alignment. The endplate angle of this device can be adjusted in-vivo ranging from zero degrees parallel to a kyphotic or lordotic final angle to customize an optimal fit in individualized patient anatomy.
Although the invention has been described with reference to several exemplary embodiments, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the invention in all its aspects. Although the invention has been described with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed; rather, the invention extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims.
