Patent Publication Number: US-11648130-B2

Title: Intervertebral devices and related methods

Description:
This application is a divisional of U.S. Pat. No. 10,799,366, U.S. patent application Ser. No. 14/120,379, entitled “Intervertebral Devices and Related Methods,” filed on May 14, 2014, which claims priority to U.S. Provisional Application Ser. No. 61/822,919, entitled “Intervertebral Devices and Related Methods,” filed May 14, 2013, U.S. Provisional Application Ser. No. 61/857,252, entitled “Intervertebral Devices and Related Methods,” Filed Jul. 23, 2013, and U.S. Provisional Application Ser. No. 61/955,757, entitled “Intervertebral Devices and Related Methods,” filed Mar. 19, 2014, each of the applications being incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Field of this Disclosure 
     This disclosure relates generally to medical devices, and more particularly, to medical devices utilized for spinal procedures. 
     Description of the Related Art 
     Degenerative disc diseases are common disorders that can impact all or a portion of a vertebral disc, a cushion-like structure located between the vertebral bodies of the spine. Degenerative disc diseases may lead, for example, to a disc herniation where the vertebral disc bulges out or extrudes beyond the usual margins of the disc and the spine. Disc herniation, in particular, is believed to be the result of excessive loading on the disc in combination with weakening of the annulus due to such factors as aging and genetics. Such degenerative disc diseases are also associated with spinal stenosis, a narrowing of the bony and ligamentous structures of the spine. Although disc herniation can occur anywhere along the perimeter of the disc, it occurs more frequently in the posterior and posterior-lateral regions of the disc, where the spinal cord and spinal nerve roots reside. Compression of these neural structures can lead to pain, parasthesias, weakness, urine and fecal incontinence and other neurological symptoms that can substantially impact basic daily activities and quality of life. 
     Temporary relief of the pain associated with disc herniation, or other degenerative disc diseases, is often sought through conservative therapy, which includes positional therapy (e.g. sitting or bending forward to reduce pressure on the spine), physical therapy, and drug therapy to reduce pain and inflammation. When conservative therapy fails to resolve a patient&#39;s symptoms, surgery may be considered to treat the structural source of the symptoms. When surgery fails to resolve a patient&#39;s symptoms, more drastic measures may include disc replacement surgery or vertebral fusion. 
     There are numerous implantable devices that have been developed for disc replacement and vertebral fusion. Such implantable devices, also referred to as cage systems, may be deployed to replace the vertebral disc and fuse the adjacent vertebrae, relieving pain and providing increased mobility to the patient. However, known implantable devices and methodologies have drawbacks. For example, many of the implantable devices currently available do not allow for an ample amount of materials to encourage bone growth to be positioned within and around the devices and adjacent vertebral bones. Such gone growth materials allow for a higher level of fusion of the adjacent vertebrae, providing increase stabilization and minimize the likelihood of further issues in the future. Also, many implantable devices are large structures that are not easily utilized in a minimally invasive procedure. Rather, they may require surgical procedures allowing greater access, which subjects the patient to higher risks of disease and prolonged infection. 
     There is a need for implantable devices intended for replacement of a vertebral disc, which allow for ample placement of bone growth material that may lead to better fusion between adjacent vertebral bones. There is a further need for such implantable devices to be provided during minimally invasive procedures, reducing the risk of infection and allowing for quicker healing of the patient. 
     BRIEF SUMMARY 
     Consistent with the present disclosure, an expandable intervertebral device may comprise a base including a bottom surface configured to interface with a first biological tissue, a first body portion slidably attached to the base and configured to move in at least a first direction with respect to the base, the first body portion including a first engaging element, and a second body portion slidably attached to the base and configured to move in at least a second direction with respect to the base. The second body portion may include a top surface configured to interface with a second biological tissue. The base may include a second engaging element such that the second engaging element couples to the first engaging element. In certain embodiments, the first and second engaging elements are configured such that the coupling of the first and second engaging elements prevents movement of the second body portion in a third direction with respect to the base when a compression force is applied between the top surface of the second body portion and the bottom surface of the base. In other embodiments, the third direction is substantially opposite to the first direction, while in still other embodiments, the third direction is substantially opposite to the first direction. 
     In yet other embodiments, the first body portion may include a first sloped surface and the second body portion may include a second sloped surface. The first sloped surface may be configured to slidably couple with the second sloped surface, such that movement of the first body portion in the first direction results in movement of the second body portion in the second direction. The first sloped surface of the first body portion may form a first acute angle with respect to a longitudinal axis of the base, and the second sloped surface of the second body portion may form a second acute with respect to the longitudinal axis of the base. In some embodiments, the first acute angle is substantially equal to the second acute angle, while in other embodiments the first acute angle is different than the second acute angle. In still other embodiments, the first sloped surface of the first body portion may form a first acute angle with respect to a longitudinal axis of the base, and the second sloped surface of the second body portion may form a second acute with respect to the longitudinal axis of the base. Movement of the second body portion relative to the first body portion may define a movement rate, the first and second acute angles may be selected to provide the movement rate. 
     In certain embodiments, the first body portion may be configured to be removably attached to a translating member, where operation of the translating member results in movement of the first body portion in the first direction, generally along a longitudinal axis of the base. In some embodiments, the base includes a longitudinal axis, and the first direction is substantially parallel to the longitudinal axis of the base, while in other embodiments, the base includes a longitudinal axis, the second direction being substantially perpendicular to the longitudinal axis of the base. In other embodiments, the first direction and the second direction are substantially perpendicular. 
     In still other embodiments, the base includes first and second ends, and a longitudinal axis extending from the first end to the second end, and each of a plurality of positions of the first body portion along the longitudinal axis of the base corresponding to a respective one of a plurality of positions of the second body portion. Each of the plurality of positions of the first body portion may correspond to a respective one of a plurality of heights of the intervertebral device. 
     In yet other embodiments, the first direction is in a direction toward a distal end of the device along a longitudinal axis of the base, while in other embodiments the first direction is in a direction toward a proximal end of the device along a longitudinal axis of the base. 
     In another aspect, a method includes providing an intervertebral device having a base, a first body portion, and a second body portion, the first body portion configured to move in at least a first direction with respect to the base and the second body portion configured to move in at least a second direction with respect to the base, the first body portion including a first engaging element and the base portion including a second engaging element; 
     moving the first body portion in the first direction, the second body portion moving in the second direction in response to movement of the first body portion, the first engaging element of the first body portion couples to the second engaging element of the base, the coupling of the first and second engaging elements preventing movement of the second body portion in a third direction. 
     In certain embodiments, the base, and the first and second body portions form a void, movement of the first body portion in the first direction results in increasing an area of the void. The method may include deploying one or more therapeutic agents within the void, the therapeutic agents including a substance to encourage bone growth, for example. A central axis of each of the base, and first and second body portions may pass through the void. 
     In other embodiments, moving the first element in the first direction results in adjusting the height of the intervertebral device. Adjusting the height may include expanding and contracting the intervertebral device. 
     In yet other embodiments, the first direction is in a direction toward a distal end of the device along a longitudinal axis of the base, while in other embodiments, the first direction is in a direction toward a proximal end of the device along a longitudinal axis of the base. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the any embodiments, as claimed. Other objects, features and advantages of the embodiments disclosed or contemplated herein will be apparent from the drawings, and from the detailed description that follows below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will be made to embodiments of the disclosure, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although certain aspects of the embodiments are generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope to these particular embodiments. In the drawings: 
         FIG.  1    is a perspective view of an intervertebral device in a first configuration. 
         FIG.  2    is a perspective view of the intervertebral device of  FIG.  1    in a second configuration. 
         FIG.  3    is a partial section view of the intervertebral device of  FIG.  1   . 
         FIG.  4    is another partial section view of the intervertebral device of  FIG.  2   . 
         FIG.  5 A  is a partial section view of a portion of the intervertebral device of  FIG.  2   . 
         FIG.  5 B  is another partial section view of a portion of the intervertebral device of  FIG.  2   . 
         FIG.  6    is a portion of the intervertebral device of  FIG.  2   . 
         FIG.  7    is a perspective view of another intervertebral device. 
         FIG.  8    is a partial section view of the intervertebral device of  FIG.  1   . 
         FIG.  9    is another partial section view of the intervertebral device of  FIG.  1   , in a different configuration. 
         FIG.  10    is a partial section view of a portion of the intervertebral device of  FIG.  9   . 
         FIG.  11    is another partial section view of a portion of the intervertebral device of  FIG.  9   . 
         FIG.  12    is a perspective view of an intervertebral device in a first configuration. 
         FIGS.  13 A- 13 C  are perspective views of the intervertebral device of  FIG.  12    in a second configuration. 
         FIG.  14    is a partial section view of the intervertebral device of  FIG.  12   . 
         FIG.  15    is a partial section view of the intervertebral device of  FIGS.  13 A- 13 C . 
         FIG.  16    is a perspective view of an exemplary delivery device. 
         FIG.  17    is a perspective view of a portion of the exemplary delivery device of  FIG.  16   . 
         FIG.  18    is a perspective view of an element of an exemplary intervertebral device. 
         FIG.  19    is a partial section view of an interface between the portion of the exemplary delivery device of  FIG.  17    and an exemplary intervertebral device. 
         FIG.  20    is another partial section view of an interface between the portion of the exemplary delivery device of  FIG.  17    and an exemplary intervertebral device. 
         FIG.  21    is a perspective view of another exemplary delivery device. 
         FIG.  22    is a partial section view of a portion of the exemplary delivery device of  FIG.  21   . 
         FIG.  23    is another partial section view of a portion of the exemplary delivery device of  FIG.  21   . 
         FIG.  24    is a perspective view of a portion of the exemplary delivery device of  FIG.  21   . 
         FIG.  25    is another partial section view of a portion of the exemplary delivery device of  FIG.  21   . 
         FIG.  26    is a perspective view of another intervertebral device in a first configuration. 
         FIGS.  27 A and  27 B  are perspective views of the intervertebral device of  FIG.  26    in a second configuration. 
         FIG.  28    is a partial section view of the intervertebral device of  FIG.  26   . 
         FIG.  29    is a partial section view of the intervertebral device of  FIG.  27 A . 
         FIGS.  30 A- 30 C  are perspective views of an exemplary delivery device interfacing with a portion of an exemplary intervertebral device. 
         FIG.  31    is a top view of another exemplary intervertebral device. 
         FIG.  32    is a partial section view of the exemplary intervertebral device of  FIG.  31   . 
         FIG.  33    is another partial section view of the exemplary intervertebral device of  FIG.  31   . 
         FIG.  34    is a partial section view of another exemplary intervertebral device. 
         FIG.  35    is another partial section view of the exemplary intervertebral device of  FIG.  34   . 
         FIG.  36    is a perspective view of another exemplary delivery device. 
         FIG.  37    is a perspective view of a portion of the exemplary delivery device of  FIG.  36   . 
         FIG.  38    is a top view of an element of the portion of the exemplary intervertebral device of  FIG.  37   . 
         FIG.  39    is a partial section view of the element of the portion of the exemplary intervertebral device of  FIG.  37   . 
         FIG.  40    is another top view of an element of the portion of the exemplary intervertebral device of  FIG.  37   . 
         FIG.  41    is another partial section view of the element of the portion of the exemplary intervertebral device of  FIG.  37   . 
         FIGS.  42 A-C  are perspective views of certain elements of the portion of the exemplary delivery device of  FIG.  37   . 
         FIG.  43    is a partial section view of a portion of the exemplary delivery device of  FIG.  36   . 
         FIG.  44    is a perspective view of an element of the exemplary delivery device of  FIG.  36   . 
         FIGS.  45 A- 45 B  are partial section views of portions of the delivery device of  FIG.  33     
         FIGS.  46 A- 46 B  are perspective views of a portion of the element  FIG.  44   . 
         FIG.  47    is a partial cut view of a portion of the element of  FIG.  44   . 
         FIG.  48    is a partial section view of a portion of the element of  FIG.  44   . 
     
    
    
     DETAILED DESCRIPTION 
     Intervertebral devices and systems, and methods of their use, are disclosed having configurations suitable for placement between two adjacent vertebrae, replacing the functionality of the disc therebetween. Intervertebral devices and systems contemplated herein are implantable devices intended for replacement of a vertebral disc, which may have deteriorated due to disease for example. The intervertebral devices and systems are configured to allow for ample placement of therapeutic agents therein, including bone growth enhancement material, which may lead to better fusion between adjacent vertebral bones. The intervertebral devices and systems are configured for use in minimally invasive procedures, if desired. 
     The following description is set forth for the purpose of explanation in order to provide an understanding of the various embodiments of the present disclosure. However, it is apparent that one skilled in the art will recognize that embodiments of the present disclosure may be incorporated into a number of different systems and devices. 
     The embodiments of the present disclosure may include certain aspects each of which may be present in one or more medical devices or systems thereof. Structures and devices shown below in cross-section or in block diagram are not necessarily to scale and are illustrative of exemplary embodiments. Furthermore, the illustrated exemplary embodiments disclosed or contemplated herein may include more or less structures than depicted and are not intended to be limited to the specific depicted structures. While various portions of the present disclosure are described relative to specific structures or processes with respect to a medical device or system using specific labels, such as “locked” or “therapeutic agents”, these labels are not meant to be limiting. 
     The expandable intervertebral devices described herein may be made from any suitable biocompatible material, including but not limited to metals, metal alloys (e.g. stainless steel) and polymers (e.g. polycarbonate), and may be formed using any appropriate process, such as screw-machining or molding (e.g. injection molding). The intervertebral devices herein may be sized for minimally invasive procedures having operating lumens at about 12 mm or less. For illustration purposes only, any expandable intervertebral device described or contemplated herein may have a height in the range from about 6 mm to about 16 mm, and a length in the range of from about 20 to about 40 mm, and a width in the range of from about 8 mm to about 16 mm. The intervertebral devices described or contemplated herein may be positioned between adjacent vertebrae through any suitable procedure, such as through a posterior lumbar interbody approach or through a transforaminal lumbar interbody approach, for example. 
     Reference will now be made in detail to the present exemplary embodiments, which are illustrated in the accompanying drawings. 
     Turning to  FIGS.  1  and  2   , a perspective view of an exemplary intervertebral device  100  includes a first element or base element  110 , a second or sliding element  140 , a third or elevating element  170 , and a drive mechanism  190 . As will be better understood in the discussion below, the elements  110 ,  140 ,  170  cooperate such that the intervertebral device  100  geometric height, H, may have a minimum, collapsed configuration, as generally depicted in  FIG.  1   , or a maximum, expanded configuration, as generally depicted in  FIG.  2   , or any height therebetween, as discussed in greater detail below. As will be better understood in light of the discussion below, the elements  110 ,  140 ,  170  include protrusions and depressions that cooperate to allow coordinated movement of each of the element  110 ,  140 ,  170  with respect to each other. For example, as the second element  140  translates from a proximal position to a distal position within the first element  110 , protrusions and depressions of the elements  110 ,  140 ,  170  cooperate resulting in the elevation of the third element  170  with respect to the first and second elements  110 ,  140 . 
     The first element  110  is configured to provide a base or outer structure for the intervertebral device  100 , retaining the remaining elements  140 ,  170  therein. The first element  110  includes a first or proximal end  112  and a second or distal end  114  and two side portions, a first side portion  116  and an opposing side portion  118 . A bottom portion  120  of the first element  110  may include one or more openings  122  to allow for therapeutic materials, such as bone growth enhancing materials, to pass therethrough. As used herein, the term “therapeutic materials” or therapeutic agents” may include any substance, including bone growth materials or drug eluding materials for example, or a product or medical device including or deploying such substances, intended for use in the medical diagnosis, cure, treatment, or prevention of disease. 
     Proximal end  112  of the first element  110  may include an opening  130  for passing a portion of one or more tools utilized for expanding, contracting, or locking the intervertebral device  100  in a specific configuration, as is discussed in greater detail below with reference to  FIGS.  3  and  4   . For example, the intervertebral device  100  may be expanded from a first position or configuration, having a height of H 1-1 , as depicted in  FIG.  1   , to a second position or configuration, having a height of H 1-2 , as depicted in  FIG.  2   , or any suitable height therebetween, and locked in any such configuration or at any such height. As used herein, the term “lock”, “locked” or “locking” used in conjunction with the intervertebral device  100 , or any other intervertebral device described or contemplated herein, shall mean to substantially maintain the position of each of the main elements, such as elements  110 ,  140 ,  170 , with respect to each other. A void or space  102  is defined by the elements  110 ,  140 ,  170  when the intervertebral device  100  takes on a collapsed configured, as depicted in  FIG.  1   , and the void or space  102  increases when the intervertebral device  100  takes on an expanded configuration, as depicted in  FIG.  2   . Therapeutic Agents may then be deployed through opening  120 , or other suitable opening, to fill the void  102  and expand out of the intervertebral device  100  to engage surrounding tissue, e.g. tissue of the vertebra. 
     The proximal end  112  of the first element  110  may also include structures, such as a threaded structure  130 T, as better shown in  FIGS.  3  and  4   , and recesses  132 , which may allow for an attachment point of one or more delivery systems, as described in greater detail below with respect to  FIG.  17   . Such attachment point may also form the basis for at least initially positioning the intervertebral device  100 , for example between two adjacent vertebrae of a spine. In other embodiments, the delivery system utilized may include tubular members through which therapeutic materials, including bone growth enhancing materials, may be introduced, for example, to internal voids or spaces within the intervertebral device  100 , and exiting through the one or more openings  120  of the element  110 , or similar openings of the remaining elements  140 ,  170 . In this way, such materials may contact surrounding tissues, such as tissues of the vertebrae. 
     The internal sidewalls of side portions  116 ,  118  of the first element  110  may include one or more protrusions  124  and one or more depressions  126 , as better viewed with respect to  FIG.  5 A . These protrusions  124  and depressions  126  include surfaces that interface with one or more surfaces of protrusions and depressions of the other elements  140 ,  170  resulting in coordinated movement. 
     The second element  140  is slidably interfaced to the first element  110  such that the second element  140  at least translates horizontally with respect to the first element  110 . Second element  140  may include a positioning structure or pin  145  that is coupled to the second element  140 . The pin  145  may be configured or adapted to move within a channel or slot  128  provided in the first element  110  to ensure that the second element  140  moves in a specific direction with respect to the element  110 . Accordingly, slot  128  and associated structure or pin  145  may be configured to form any desirable angle with respect to a longitudinal centerline of element  110 . As depicted, slot  128  is substantially parallel to a longitudinal line of element  110  and, therefore, the element  130  moves in a direction substantially perpendicular to element  110 . The second element  140  may also include one or more openings  142  that are in fluid communication with openings of one or more other elements  110 ,  170 , such as openings  122  of the first element  110 , to allow for passage of therapeutic agents therethrough. 
     The third element  170  includes a top surface  171  having one or more openings  172  that are in fluid communication with void  102 . The top surface may include other structures to enable or encourage contact and retention with respect to a bodily tissue, such as tissue of a vertebra. The third element  170  may include one or more side members  180 , each having one or more protrusions  184  and one or more depressions  186  and corresponding surfaces that cooperate with surfaces of the first and second elements  110 ,  140  to allow for cooperative movement. 
     Turning to  FIGS.  3  and  4   , which depict the intervertebral device  100  in cross-section down a central longitudinal axis, drive mechanism  190  includes a retaining cap  192  and drive member  194 . The drive member  194  may include drive points  194 D configured to receive a driver for rotational control of the member  194 . The retaining cap  192  may be fixedly attached to the first element  100  to retain the drive member  194  within the intervertebral device  100  and provide a surface force to allow for the translation of the second element  140 . For example, as depicted, the drive member  194  may include a proximal drive point  194 D P  located closer to proximal end  112  of the first element  110 , and a distal drive point  194 D D  located closer to distal end  112  of the first element  110 . As is discussed in greater detail below, a driver may enter through opening  130 , pass through void  102 , and engage the proximal drive point  194 D P , rotation of the driver resulting in corresponding rotation of the driver member  194 , for example. The retaining cap  192  may include an opening  193  for driver access to the distal drive point  194 D D , if desired. 
     The driver member  194  includes a helical threaded portion  194 T configured or adapted to interface with a helical threaded portion  140 T of the second element  140 . Accordingly, rotation of the drive member  194  results in axial movement of the second member  140 . More specifically, if the drive member  194  is rotated in a first direction, the second element  140  will move in a distal direction, toward distal end  114  of the first element  110 , and if the drive member  194  is rotated in a second opposing direction, the second element  140  will move in a proximal direction, toward proximal end  112  of the first element  110 . Since the threads  194 T,  140 T are continuous, the second element  140  may be positioned at any point along a longitudinal axis of the first element  110 , each point along the longitudinal axis corresponding to a respective height of the third element  170 . 
     With specific reference to  FIG.  4   , depicting the intervertebral device  100  in cross-section through a central geometric plane, the second element  140  includes side members  150 A (not shown) and  150 B, collectively referred to as side members  150 . As depicted, side member  150 B includes one or more protrusions  154  and one or more depressions  156  that interface with other structures of the third element  170  such that when the second element  140  translates distally the third element  170  moves at least vertically, increasing an overall height of the intervertebral device  100 . For example, protrusion  154  includes a sloped surface  154   S1  that interfaces with an adjacent sloped surface  184 D S3  of the side member  180 D of the third element  170 . As the second element  140  moves distally, the interaction of these sloped surfaces  154   S1 ,  184 D S3  results in the vertical displacement of the third element  170 . The third element  170  may also interface with sloped surfaces of the first element  110  to further encourage this vertical displacement. For example, the first element  110  includes a sloped surface  110 S adjacent to a sloped surface  184 D S1  associated with side member  180 D, the interaction of the sloped surfaces  110   s ,  184 D S1  further encouraging vertical displacement of the third element  170  as the second element  140  translates distally within the first element  110 . 
     With reference now to  FIGS.  5 A and  5 B , the interaction of first element  110  and the third element  170  will be described in greater detail. For discussion purposes only, the second element  140  has been removed. Additionally, while this discussion considers only a single side member  180 D, this discussion also applies to other side members  180  of the third element  170 . As depicted, side member  180 D includes protrusions  184 D and depressions  186 D, the protrusions  184 D defining corresponding surfaces  184 D S1-S3 . The first element  110  includes protrusions  124 B and depressions  126 B on the inner surface of side portion  118 . Protrusion  124 B 1  includes a surface  124 B 1   S , and protrusion  124 B 2  includes a first surface  124 B 2   S1  and a second surface  124 B 2   S2 , surface  184 D S1  interfacing with surface  124 B 1   S  and surface  184 D S2  interfacing with surface  124 B 2   S1 , such that a portion of side member  180 D is able to move within and along depression  126 B 1 . Side member  180 D also defines a surface  184 D S3  that, along with surface  184 C S1  of side member  184 C, interfaces with corresponding surfaces of second element  140 , as discussed below with reference to  FIG.  6   . 
     Turning to  FIG.  6   , interaction between the geometric features of the second element  140  and the third element  170  are depicted and, for discussion purposes only, the first element  110  has been removed. Additionally, while this discussion considers only a single side portion  150 A of the second element  140  and its interaction with side members  180 A,  180 B of the third element  170 , this discussion also applies to side portion  150 B of the second element  140  and its corresponding interaction with side members  180 C,  180 D of the third element  170 . As depicted, side portion  150 A includes first and second protrusions  144 A 1 ,  144 A 2 , and first and second depressions  146 A 1 ,  146 A 2 . The side member  180 A of the third element  170  includes protrusion  184 A having a first side surface  184 A S1  and a second side surface  184 A S2 . The first depression  146 A 1  of the second element  140  includes a first side surface  146 A 1   S1  and a second side surface  146 A 1   S2 . The side member  180 A of the third element  170  is slidably received in the depression  146 A 1  of the second element  140 , the surfaces  184 A S1 ,  184 A S2  interfacing with surfaces  146 A 1   S1 ,  146 A 1   S2 , respectively. Accordingly, as the second element  140  distally translates in a direction generally depicted by arrow A D , side surface  146 A 1   S1  couples with side surface  184 A S1  to move the third element  170  at least vertically away from the second element  140 . Similarly, as the second element  140  proximally translates in a direction generally depicted by arrow A P , side surface  146 A 1   S2  couples with side surface  184 A S2  to move the third element  170  at least vertically toward the second element  140 . 
     Turning to  FIG.  7   , an exemplary intervertebral device  200  includes a first element  210 , a second element  240 , a third element  270 , and a drive mechanism  290 . Intervertebral device  200  is similar to intervertebral device  100 , except the elements  210 ,  240 ,  270  of the device  200  have geometric characteristics that cooperate in such a way as to allow, in operation, the third element  270  to move vertically with respect to a longitudinal axis of the first element  210 . The various surfaces of the element  110 ,  140 ,  170  of the device  100  cooperated to allow, in operation, the third element  170  to move vertically, as well as horizontally, with respect to a longitudinal axis of the first element  110 . 
     Element  210  includes a proximal end  212  and a distal end  214 , and a first side  216  and a second side  218 . The element  210  further includes a bottom portion  220  having one or more openings  222 . The element  210  also includes an opening  230  at the proximal end  212 , the opening allowing a passageway for medical tools or therapeutic agents to an interior void  202  of the device  200 . The second element  240  is similar to element  140 , having geometric structures and surfaces that interface with the third element, to allow for the third element to move vertically with respect to a longitudinal axis of the first element  210 . The third element  270  has a surface  271  adapted to engage a biological tissue surface, the element  270  including one or more openings  272  in fluid communication with the interior void  202  and the one or more openings  222  of the bottom surface  220  of the first element  210 . Third element  270  further includes an side member  280 B that has vertical surfaces to encourage vertical movement of the third element  270  with respect to the first element when operated. 
     Turning to  FIGS.  8  and  9   , the intervertebral device  200  is depicted in cross-section along a central longitudinal axis. As shown, the device  200  includes drive mechanism  290  that includes a retaining cap  292  and drive member  294 , similar to the drive mechanism  190  of the intervertebral device  100 . The drive member  294  may include drive points  294 D configured to receive a driver for rotational control of the member  294 . The retaining cap  292  may be fixedly attached to the first element  200  to retain the drive member  294  within the intervertebral device  200  and provide a surface force to allow for the translation of the second element  240 . For example, as depicted, the drive member  294  may include a proximal drive point  294 D P  located closer to proximal end  212  of the first element  210 , and a distal drive point  294 D D  located closer to distal end  212  of the first element  210 . Similar to operation of the drive mechanism  190 , a driver may enter through opening  230 , pass partially through void  202 , and engage the proximal drive point  294 D P , rotation of the driver resulting in corresponding rotation of the driver member  294 , for example. The retaining cap  292  may include an opening  293  for driver access to the distal drive point  294 D D , if desired. 
     The driver member  294  includes a helical threaded portion  294 T configured or adapted to interface with a helical threaded portion  240 T of the second element  240 . Accordingly, rotation of the drive member  294  results in axial movement of the second member  240 . More specifically, if the drive member  294  is rotated in a first direction, the second element  240  will move in a distal direction, toward distal end  214  of the first element  210 , and if the drive member  294  is rotated in a second opposing direction, the second element  240  will move in a proximal direction, toward proximal end  212  of the first element  210 . Since the threads  294 T,  240 T are continuous, the second element  240  may be positioned at any point along a longitudinal axis of the first element  210 , each point along the longitudinal axis corresponding to a respective height of the third element  270 . 
     As shown in  FIG.  9   , the third element  270  includes a side member  280 D that includes side surfaces which are vertical with respect to a longitudinal axis of the first element  210 . The side member  280 D, during operation, moves vertically in a corresponding depression  218 D in the inner wall service of side  218 . Turning to  FIG.  10   , the interaction of the first element  210  and the third element  270  of the intervertebral device  200  is depicted in greater detail, the second element  240  removed for discussion purposes only. As shown, the side member  280 D is slidably positioned within the depression  218 D. Turning also to  FIG.  11   , the interaction between the geometric features of the second element  240  and the third element  270  are depicted and, for discussion purposes only, the first element  210  has been removed. Additionally, while this discussion considers only a single side portion  250 A of the second element  240  and its interaction with side members  280 A,  280 B of the third element  270 , this discussion also applies to side portion  250 B of the second element  240  and its corresponding interaction with side members  280 C,  280 D of the third element  270 . As depicted, side portion  250 A includes first and second protrusions  244 A 1 ,  244 A 2 , and a depression  246 A. The side member  280 A of the third element  270  includes protrusion  284 A having a first side surface  284 A S1  and a second side surface  284 A S2 . The depression  246 A of the second element  240  includes a first side surface  246 A S1  and a second side surface  246 A S2 . The side member  280 A of the third element  270  is slidably received in the depression  246 A of the second element  240 , the surfaces  284 A S1 ,  284 A S2  interfacing with surfaces  146 A S1 ,  146 A S2 , respectively. Accordingly, as the second element  240  distally translates, as generally depicted by arrow A D , side surface  246 A S1  couples with side surface  284 A S1  to move the third element  270  vertically away from the second element  240 . Similarly, as the second element  240  proximally translates in a direction generally depicted by arrow A P , side surface  246 A S2  couples with side surface  284 A S2  to move the third element  270  vertically toward the second element  140 . 
     Turning to  FIG.  12   , a third exemplary intervertebral device  300  includes a first element  310 , a second element  340 , a third element  370 , and a drive mechanism  390 . Intervertebral device  300  is similar to devices  100  and  200 , except as the second element  340  translates distally, both the first element  310  and the third element  370  move vertically away from the second element  340 . Turning to  FIGS.  13 A and  13 B , the intervertebral device  300  is depicted in an expanded configuration. As shown, protrusions  344  of the second element  340  are configured to be slidably coupled to corresponding depressions  326  in the first element  310 . Additionally, protrusions  384  of side members  380  of the third element  370  are configured to be slidably coupled to corresponding depressions  346  of the second element  340 . In a similar fashion as described with respect to the first and second devices  100 ,  200 , as the second element translates distally through operation of the drive mechanism  390 , creating or enlarging a void  302 , the geometric structures and surfaces of the elements  310 ,  340 ,  370  cooperate to move both the first element  310  and the third element  370  vertically away from the second element  340 . The configuration of the intervertebral device  300  allows for a greater overall height of device  300  to be achieved with respect to an initial height. Accordingly, the intervertebral device  300  may be initially sized to be delivered through minimally invasive means, e.g. positioned through an endoscopic approach. Once positioned the intervertebral device  300  may then be expanded to a desired height. Turning to  FIG.  13 C , with the device  300  in an expanded configuration and due to the specific design of the geometric structures of the elements  310 ,  340 ,  370 , a large void  302  can be achieved. This void  302  can then be filled with therapeutic agents, to encourage healing and/or bone growth around and to the device  300 . 
     Now turning to  FIGS.  14  and  15   , additional information regarding the operation of intervertebral device  300  will be described.  FIG.  14    depicts the device  300  in cross-section, and in a collapsed configuration, while  FIG.  15    depicts the device  300  in cross-section, and in an expanded configuration. As shown, intervertebral device  300  includes an alternative element  310 A within which a distal portion of the second element translates. Element  310 A is vertically slidable with respect to the first element  310  and the third element  350 . As with the drive mechanism  190 , drive member  394  includes a helical thread  394 T that interfaces with corresponding helical thread  340 T of the second element  340 . Rotation of the drive member in a first direction results in distal movement of the second element  340  with respect to the element  310 A. Rotation of the drive member in a second opposing direction results in a proximal movement of the second element  340  with respect to the element  310 A. The second element  340  includes multiples protrusions  344 B 1 - 344 B 3 , as well as multiple depressions  346 B 1 - 346 B 3 , which interface or couple with corresponding depressions and protrusions of the third element  370  in a similar fashion as describes above with respect to intervertebral devices  100  and  200 . The second element  340  includes additional multiple protrusions  344 D and depressions  346 D on the opposing surface of side member  340 B, which interface or couple with corresponding protrusions  324 B 1 -B 3  and depressions  326 B 1 -B 2 , respectively. As with other intervertebral devices described or discussed herein, the protrusions and depressions of the elements  310 ,  340 ,  370  cooperate such that as the second element  340  translates distally, various surfaces of the protrusions and depressions interface or couple such that the first element  310  moves at least vertically away from the second element  340 , and the third element  370  moves at least vertically away in an opposing direction. With the intervertebral device  300  in an expanded configuration the void  302  is maximized allowing for therapeutic agents to be deployed therein, the therapeutic agents exiting various openings, such as openings  372 ,  322 , to encourage bone growth around or adjacent to the device  300 . As the second element  340  translates in a proximal direction, the protrusions and depressions of the elements  310 ,  340 ,  370  cooperate to take on a more collapsed configuration. 
     Turning now to  FIG.  16   , a delivery system  400  may be used to position intervertebral devices  100 ,  200 ,  300 , or any other intervertebral devices discussed or contemplated herein, between two adjacent vertebrae, and adjust the height of the corresponding device  100 ,  200 ,  300  as desired. While the delivery system  400  is depicted and discussed with respect to an intervertebral device  100 A depicted in  FIGS.  18 - 21   , such discussion and corresponding operation applies to any intervertebral devices any other intervertebral devices discussed or contemplated herein. The delivery system  400  includes a handle  402 , operational controls  404  and an elongated portion  406  ending in a distal portion  408 . The distal portion  408  of the delivery system  400  is configured to engage and position an intervertebral device, such as device  100 A, within a patient&#39;s body. A first operational control  404 A is coupled to a first elongate member  410 A (not shown) extending within the elongate portion  406 , from the control  404 A to the distal end  408 , a distal end of the elongate member  410 A configured to couple the delivery system  400  to the intervertebral device  100 A. A second operation control  404 B is coupled to a second elongate member  410 B (not shown) extending within the elongate portion  406 , from the control  404 B to the distal end  408 , the distal end of the elongate member  410 B configured to operate the intervertebral device  100 A, e.g. adjust a height of the device  100 A. 
     Turning to  FIG.  17   , the elongate member  410 A ends in a threaded portion  410 AT at the distal portion  408 , and elongate member  410 B ends in distal portion  412  including a distal driver  412 D. The elongate member  410 A is rotatably slidable to elongate member  410 B. The distal portion  408  may also include one or more mating structures  420  for engaging similar mating structures as part of the intervertebral device  110 A, one or more mating structures  134  as shown in  FIG.  18    for example. The mating structures  420 ,  134  enable the delivery system  400  to maintain a desired orientation with respect to the device  110 A. The distal end  408  may also include further engaging structures, such as threaded portion  410 AT of the elongate member  410 A, to maintain a hold on the device  110 A during positioning thereof. The distal driver  412 D of the distal portion  412  may be configured to enter a void within the intervertebral device  100 A and couple with a drive member, e.g. drive member  194  of drive mechanism  190 A. 
     Turning to  FIG.  19   , operation of the first control  404 A may act to rotate the threaded portion  410 AT of the elongate member  410 A, the threaded portion  410 AT interfacing to the threaded portion  130 T of the first element  110 A of the intervertebral device  100 A to fixedly attach the device  100 A to the delivery system  400 . Once the device  100 A is positioned within a body, between adjacent vertebrae for example, the second control  404 B may be operated to rotate the driver  412 D of the device  400 , rotation of the driver  412 D acting to rotate drive member  194 A resulting in adjustment of the overall height, H, of the intervertebral device  100 A, as described above with respect to intervertebral device  100 . Turning also to  FIG.  20   ,  FIG.  20    depicts the intervertebral device  100 A in an expanded configuration, the second element  140  moving to a distal end of the first element  110 A. 
     Turning now to  FIG.  21   , an alternative delivery system  400 A is similar to the delivery system  400  of  FIG.  16   , however includes a third control  404 C that operates a deflectable distal portion  408 A. Turning to  FIG.  22   , control  404 C is coupled to the elongate member  406 A through threaded portion  404 CT that interfaces with threaded portion  406 AT. Control  404 C is further coupled to a proximal end of an elongate member  410 C. Elongate member  406  is coupled to distal portion  408 A through a hinge  416 . A distal end of the elongate member  410 C is coupled to distal portion  408 A of delivery system  400 A through a hinge  418 . Distal portion  408 A is also coupled to a central lumen of an elongate member  410 A through gear  414 . Accordingly, rotation of the control  404 C is converted into axial movement of elongate member  410 C, which deflects the distal portion  408 A with respect to elongate member  406 A, as depicted in  FIG.  23   . Elongate member  410 A may include a stop  420  to prevent or limit axial movement of the elongate member  410 C, which ultimately limits the deflection of the distal end  408 A. 
       FIG.  24    depicts the distal portion  408 A deflected and placement of elongate member  410 B, which ends in distal portion  412  and driver  412 D. As shown, the distal portion  408 A includes one or more protrusions  420 A which are configured to engage corresponding recesses on the intervertebral device, such as device  100  for example. The elongate member  410 B may include a flexible portion positioned adjacent to the gear  414  such that the member  410 B bends with the deflection of the distal portion  408 A.  FIG.  25    depicts the delivery system  400 A interfaced to an exemplary intervertebral device, such as intervertebral device  100 . The elongate member  410 B has been removed for illustration purposes only. In operation, the driver  412 D of the distal end  412  of the elongate member  410 B would interface with a drive member of the intervertebral device, the delivery system  400 A adjusting a height of the intervertebral device, as described above. 
     Turning to  FIGS.  26  and  27 A , a perspective view of an exemplary intervertebral device  500  includes a first element  510 , a second element  540 , and a third element  570 . As will be better understood in the discussion below, the elements  510 ,  540 ,  570  cooperate such that the intervertebral device  500  geometric height may have a minimum, collapsed configuration, as generally depicted in  FIG.  26   , and a maximum, expanded configuration, as generally depicted in  FIG.  27 A  and discussed in greater detail below. 
     The first element  510 , which may also referred to as base  510  or base element  510 , is configured to provide a base or outer structure for the intervertebral device  500 , and includes a first end  512 , a second end  514 , and two side portions, a first side portion  516  and an opposing side portion  518 . A bottom portion  520  includes one or more openings  522  allowing for therapeutic agents or materials, including bone growth enhancing materials, to pass therethrough. It should be readily understood that the second and third elements  540 ,  570  may also include similar openings. A proximal end, e.g. end  512 , may include an opening  530  for passing a portion of one or more tools utilized for delivery of said therapeutic agents, or expanding, contracting, or locking the intervertebral device  500  in a specific configuration, as is discussed in greater detail below with reference to  FIGS.  30 A- 30 C . 
     The intervertebral device  500  may be expanded or contracted to any suitable height, H, between a first collapsed height H 5-1  and a second expanded height H 5-2 , with reference to  FIGS.  26  and  27 A , respectively. For example, the intervertebral device  500  may be expanded from a first position, having the height of H 5-1  in  FIG.  26   , to a second position, having the height of H 5-2  in  FIG.  27 A , or any height therebetween, and locked in any position. As stated above, the term “lock”, “locked” or “locking used in conjunction with the intervertebral device  500 , or other intervertebral devices described or contemplated herein, shall mean to substantially maintain the position of each of the elements  510 ,  540 ,  570  with respect to each other. The end  512  may also include structures, such as threaded structure  530 T, which may allow for attachment points to a delivery system, as described above with respect to intervertebral device  100 , for example. Such attachment points may also form the basis for at least initially positioning the intervertebral device  500 , for example positioning the device  500  between two adjacent vertebrae. The elements  510 ,  540 ,  570  are configured to create a void  502  within the intervertebral device  500 , the void  502  increasing during expansion of the intervertebral device  500  from a collapsed configuration to an expanded configuration, for example. In other delivery system embodiments, the delivery system may include tubular members through which therapeutic agents may be introduced, for example, to internal spaces or voids within the intervertebral device  500  and exiting through the one or more openings  522  of the element  510 , or similar openings of the remaining elements  540 ,  570 . In this way, such therapeutic agents may contact surrounding tissues, such as bone tissue of the vertebra. 
     The third element  570  is slidably interfaced to the first element  510  such that the third element  570  at least slides vertically with respect to the first element  510 . The third element  570  may include one or more openings  572  in a top portion or top surface  571  thereof to allow for passage or introduction of therapeutic agents therethrough. The top portion  571  may include one or more protrusions  574  that may aide in holding the top portion  571  immobile with respect to adjacent structures or biological tissue, such as vertebrae structures for example. While only a few protrusions  574  are identified, additional or less protrusions  574  may be utilized. Additionally such protrusions, like protrusions  574 , may be constructed from any biocompatible material and in any suitable form, and may be used with other elements or surfaces of intervertebral device  500 , or any other intervertebral device described or contemplated herein. For example, sidewalls  516 ,  518  of element  510  may include one or more protrusions (not shown), similar to protrusions  574 , and a bottom portion  520  of base  510  may include one or more protrusions, similar to protrusions  574 . 
     Turning specifically to  FIG.  27 A , the element  510  may include a positioning structure or protrusion  524  which may be configured or adapted to move within a corresponding channel  576  provided in element  570  to ensure that the element  570  moves in a specific direction with respect to the element  510 . Accordingly, channel  576  and associated structure  524  may be configured to form any desirable angle with respect to a longitudinal axis of element  510 . As depicted, channel  574  is substantially perpendicular to a longitudinal axis of element  510  and, therefore, the element  570  moves in a direction substantially perpendicular to the longitudinal axis of element  510 . 
     Turning to  FIG.  27 B , the intervertebral device  500  is depicted in an expanded configuration and the viewpoint is from the first end  512 . The elements  510 ,  540 ,  570  are configured such that when in an expanded configuration the open space or void  502  is defined, e.g., as seen through opening  530  or opening  572 . In this way, once the device  500  is deployed therapeutic agents may be positioned within the void  502  from the first end  512  to the second end  514  and into voids of the other elements  540 ,  570 . Such material may further flow out of the open space via additional openings, such as openings  572  and  522 , positioned about the elements  510 ,  540 ,  570 . 
     Turning to  FIG.  28   , an elevation view depicting the elements  510 ,  540 ,  570  in cross-section is shown. The third element  570  may include a plurality of sloped surfaces  578  that are configured or adapted to contact a respective one of a plurality of sloped surfaces  548  of second element  540 . Accordingly, as the second element or sliding element  540  translates between the first end  512  and the second end  514  of the element  510 , the sloped surfaces  548  contact and slide along corresponding respective sloped surfaces  578  of the third element  570  resulting in movement of the element  570  in a direction defined by channel  574 , and the sloped surfaces  548 ,  578 . As depicted, translation of sliding element  540  from the first end  512  toward the second end  514  results in movement of the element  570  in a vertical direction away from the base element  510 . Translation of the sliding element  540  from the second end  514  toward the first end  512  results in movement of the element  540  in a vertical direction toward the base element  510 . 
     The first element  510  or base element  510  includes a plurality of engaging elements  536  that protrude from a top inner surface of the bottom portion  520  of element  510 . Second element  540  includes a plurality of engaging elements  550 , at least one engaging a respective one of the plurality of engaging elements  536 . While depicted as being integral to the respective elements  510 ,  540 , the engaging elements  536 ,  550  may be individual parts attached or affixed to the surfaces of the base element  510  and sliding element  540 , respectively. The engaging elements  536 ,  550  are depicted as having similar shapes, e.g., triangular portions, however in other configurations, the shapes can be dissimilar. For example, each of the engaging elements  550  may include a concave surface while each of the engaging elements  536  may include a corresponding mating convex surface. The shapes of the engaging elements  536 ,  550  may also be non-mating surfaces such that gaps exist at the interface between the engaging elements  536 ,  550 , for example. Also, while depicted as triangular structures, each of the elements  536 ,  550  may be nonsymmetrical along its vertical central axis, passing through the tip of each element  536 ,  550 . 
     The intervertebral device  500  is configured such that applying a lateral force to the sliding element  540  to translate the element  540  between the first and second ends  512 ,  514  of base member  510 , results in each engaging element  550  sliding up and over a corresponding engaging element  536 , and engaging an adjacent engaging element  536  in the direction of the movement of sliding element  540 . Accordingly, sliding element  540 , while primarily moving along the longitudinal axis of the base element  510 , also move vertically in accordance with the geometry outline and coupling of the engaging elements  550 ,  536  of the sliding element  540  and base element  510 , respectively. 
     Turning back to  FIGS.  26  and  27 A , a plurality of pins  544  are coupled to sliding member  540  and extend through corresponding openings  528  in the side portions  516 ,  518  of base element  510 . With the intervertebral device  500  in the collapsed configuration, as depicted in  FIG.  26   , the sliding element  540  is nearer the first end  512 , the pins  544  being nearer the first end  512 , as well. With the intervertebral device  500  in the expanded configuration, as depicted in  FIG.  27 A , the sliding element  540  is nearer the second end  514 , the pins  544  being nearer the second end  514  as well. The openings  523  of the first element  510  are spaced to allow some vertical travel of the sliding element  540  and pins  544  in accordance with the geometrical shapes, e.g. height, of the engaging elements  550 ,  536 . It is noted that by adjusting the slope of each side surface of the engaging elements  550 ,  536  the translational force to move the sliding element  540  in the presence of a compression force between the top portion  571  of element  570  and the bottom portion  520  of the base element  510  may differ in accordance with the corresponding element  550 ,  536  sloped surfaces. The slopes of each side surface of the engaging elements  550 ,  536 , which may be continuous or may not be continuous, may be configured to encourage movement of the sliding element  540  in a first direction along the longitudinal axis of the base  510  and discourage movement of the sliding element  540  in a second opposite direction. In any case, the engaging elements  550 ,  536  are configured, e.g., with suitable sloped surfaces or the like, to become locked or immovable when a compression force exists between the third element  570  and the base element  510 . 
     Turning now to  FIG.  29   , the intervertebral device  500  is depicted in an expanded configuration. With a lateral force applied to sliding element  540  moving the element  540  toward end  514 , in a ratcheting manner, for example, the engaging elements  550 ,  536  continuously engage and disengage with adjacent opposing engaging elements  550 ,  536 . As the element  540  translates, the third element  570  moves vertically to increase the overall height of the device  500 . With a compression force applied between the third element  570  and the base element  510 , e.g. when the device  500  is positioned between adjacent tissue surfaces, such as two adjacent vertebrae, the engaging elements  550 ,  536  of the sliding element  540  and base element  510 , respectively, engage and prevent the sliding element  540  to translate further. 
     Turning to  FIGS.  30 A- 30 C , an exemplary tool  600  utilized to translate sliding element  540 , or similar sliding elements discussed or described herein, includes a distal end  602  having a protrusion  604  adjacent to a groove  606 . The protrusion is adapted to fit a groove  566  at a proximal end of the sliding element  540 . As depicted in  FIG.  30 A , the tool  600  is angled or rotated along its axis such that the protrusion  604  freely enters the proximal end of the sliding element  540 , as depicted in  FIG.  30 B . Once inserted, the tool  600  may be rotated in a direction indicated by arrow  30 A such that the protrusion  604  is positioned within the groove  566  of the proximal end of the sliding element  540  and held in place through the cooperation of the protrusion  604  and a protrusion  567  at the proximal end of sliding element  540 , as depicted in  FIG.  30 C . 
     The groove  566  of the sliding element  540  cooperates with the protrusion  604  of the tool  600  to rigidly attach the tool  600  to the element  540 . Once the tool  600  is rigidly attached to the sliding element  540  a user can translate the sliding element  540  through corresponding translation of the tool  600 . As described above, translation of the tool  600 , which results in the translation of the sliding element  540 , further results in the sliding element  540  to move between the ends  512 ,  514  of the base member  510 . As the sliding element  540  translates or moves between the ends  512 ,  514 , the element  570  moves in a vertical direction with respect to the base element  510  to change the overall height, H, of the intervertebral device  500 . As should be readily understood, the tool  600  may extend from a point within a body structure to a point outside of the body. 
     Turning now to  FIG.  31   , another exemplary intervertebral device  700  includes a first or base element  710 , a second or sliding element  740 , and a third element  770 . The intervertebral device  700  is similar to the intervertebral device  500 , but the elements  710 ,  740 ,  770  of the device  700  include different geometric structures as compared to intervertebral device  500 . The intervertebral device  700  includes a distal end  712  and a proximal end  714 , the distal end  712  including a different geometric structure used for positioning and operating the device  700 . 
     Turning to  FIGS.  32  and  33   , a perspective view of the exemplary intervertebral device  700  is depicted in cut view along section A-A of  FIG.  31   . As with other intervertebral device described or contemplated herein and better understood in light of the discussion below, the elements  710 ,  740 ,  770  cooperate such that the intervertebral device  700  geometric height, H 7 , may have a minimum, collapsed configuration, as generally depicted in  FIG.  32   , and a maximum, expanded configuration, as generally depicted in  FIG.  33    and discussed in greater detail below. 
     The first element  710 , also referred to as base  710  or base element  710 , is configured to provide a base or outer structure for the intervertebral device  700 , and includes first end  712 , second end  714 , and two side portions, a first side portion  716  and an opposing side portion  718 . A bottom portion  720  includes one or more openings  722  allowing for therapeutic agent to pass therethrough. It should be readily understood that the second and third elements  740 ,  770  may also include similar openings. The proximal end  712 , may include an opening  730  for passing a portion of one or more tools utilized for delivery of said therapeutic materials, or expanding, contracting, or locking the intervertebral device  700  in a specific configuration. 
     The intervertebral device  700  may be expanded or contracted to any suitable height, H 7 , between a first collapsed height H 7-1  and a second expanded height H 7-2 , with reference to  FIGS.  32  and  33   , respectively. For example, the intervertebral device  700  may be expanded from a first position, having the height of H 7-1  in  FIG.  32   , to a second position, having the height of H 7-2  in  FIG.  33   , or another position therebetween, and locked in the position. The proximal end  712  may also include structures, such as protrusions  730 P and grooves  730 G, which may allow for attachment points to a delivery system (not shown), as described below with respect to delivery device  800  of  FIG.  38   . Such attachment points may also form the basis for at least initially positioning the intervertebral device  700 , for example between two adjacent vertebrae. As described in greater detail below, the delivery system  800  may include tubular members through which therapeutic agents may be introduced, for example, to internal spaces within the intervertebral device  700  and exiting through the one or more openings  722  of the element  710 , or similar openings of the remaining elements  740 ,  770 . In this way, such agents or materials may contact surrounding tissues, such as bone tissue. 
     The third element  770  is slidably interfaced to the first element  710  such that the third element  770  at least slides vertically with respect to the first element  710 . The third element  770  may include one or more openings  772  in a top portion  771  thereof to allow for passage or introduction of therapeutic elements or bone growth enhancing materials therethrough. The top portion  771  may include one or more protrusions  774  that may aide in holding the top portion  771  immobile with respect to adjacent structures or biological tissue, such as vertebrae structures for example. While only a few protrusions  774  are identified, additional or less protrusions  774  may be utilized. Such protrusion structures  774  may be constructed from any biocompatible material and in any suitable form and may be applied to any embodiment described or contemplated herein. Additionally, sidewalls  716  of element  710  may include one or more protrusions (not shown), and a bottom portion  720  of base  710  may include one or more protrusions  721 . Protrusions  721  may, for example, may be similar to protrusions  774 , which may aide in holding a bottom portion  720  immobile with respect to adjacent structures or biological tissue, such as vertebrae structures for example. 
     Turning specifically to  FIG.  33   , the element  710  may include a positioning structure or protrusion similar to the protrusion  524  of the base element  510  of device  500 , which may be configured or adapted to move within a corresponding channel similar to the channel  576  provided in element  570  of device  500 , to ensure that the element  770  moves in a specific direction with respect to the element  710 . Accordingly, as with the device  500 , the channel and associated structure may be configured to form any desirable angle with respect to a longitudinal axis of element  710 . The channel of element  770  is substantially perpendicular to a longitudinal axis of element  710  and, therefore, the element  770  moves in a direction substantially perpendicular to the longitudinal axis of element  710 . 
     As with the intervertebral device  500 , a void or space  702  is defined by the first, second, and third element  710 ,  740 ,  770  of the intervertebral device  700 , the void increasing as the device  700  transitions from a collapsed configuration to an expanded configuration. In this way, once the device  700  is deployed therapeutic agents may be positioned within the void  702  from the first end  712  to the second end  714 . Such agents may further flow out of the open space via additional openings, such as openings  772  and  722 , positioned about the elements  710 ,  740 ,  770 . 
     Turning back to both  FIGS.  32  and  33   , the third element  770  may include a plurality of sloped surfaces  778  that are configured or adapted to contact a respective one of a plurality of sloped surfaces  748  of second element  740 . Accordingly, as the second element or sliding element  740  translates between the first end  712  and the second end  714  of the element  710 , the sloped surfaces  748  contact and slide along corresponding respective sloped surfaces  778  of the third element  770  resulting in movement of the element  770  in a vertical direction, e.g. defined by a channels and wall structures between the first element  710  and the third element  770 . As depicted, translation of sliding element  740  from the first end  712  toward the second end  714  results in movement of the element  770  in a vertical direction away from the base element  710 . Translation of the sliding element  570  in a direction from the second end  714  toward the first end  712  results in movement of the element  740  in a vertical direction toward the base element  710 . 
     The first element or base element  710  includes a plurality of engaging elements  736  that protrude from a top inner surface of the bottom portion  720  of element  710 . Second element  740  includes a plurality of engaging elements  750 , at least one of the elements  750  engaging a respective one of the plurality of engaging elements  736 . While depicted as being integral to the respective elements  710 ,  740 , the engaging elements  736 ,  750  may be individual parts attached or affixed to the surfaces of the base element  710  and sliding element  740 , respectively. As with the engaging elements  536 ,  550  of the intervertebral device  500 , the engaging elements  736 ,  750  are depicted as having similar shapes, e.g., triangular portions, however in other configurations, the shapes can be dissimilar, or may be nonsymmetrical along its vertical central axis, passing through the tip of each element  736 ,  750 . 
     As with intervertebral device  500 , the intervertebral device  700  is configured such that applying a lateral force to the sliding element  740  to translate the element  740  between the first and second ends  712 ,  714  of base member  710 , results in each engaging element  750  sliding up and over a corresponding engaging element  736 , and engaging an adjacent engaging element  736  in the direction of the movement of sliding element  740 . Accordingly, sliding element  740 , while primarily moving along the longitudinal axis of the base element  710 , also move vertically in accordance with the geometry outline and coupling of the engaging elements  750 ,  736  of the sliding element  740  and base element  710 , respectively. 
     The intervertebral device  700  further includes a plurality of pins  745  coupled to sliding member  740  and extending through corresponding openings  728  in the side portions  716 ,  718  of base element  710 . With the intervertebral device  700  in the collapsed configuration, as depicted in  FIG.  32   , the sliding element  740  is nearer the first end  712 , the pins  745  being nearer the first end  712 , as well. With the intervertebral device  700  in the expanded configuration, as depicted in  FIG.  33   , the sliding element  740  is nearer the distal end or second end  714 , the pins  745  being nearer the second end  714  as well. The openings  728  of the first element  710  are spaced to allow some vertical travel of the sliding element  740  and pins  745  in accordance with the geometrical shapes, e.g. height, of the engaging elements  750 ,  736 . It is noted that by adjusting the slope of each side surface of the engaging elements  750 ,  736  the translational force to move the sliding element  740  in the presence of a compression force between the top portion  771  of element  770  and the bottom portion  720  of the base element  710  may differ in accordance with the corresponding element  750 ,  736  sloped surfaces. The slopes of each side surface of the engaging elements  750 ,  736 , which may be linear or may be nonlinear, may be configured to encourage movement of the sliding element  740  in a first direction along the longitudinal axis of the base  710  with respect to the sliding element  740  in a second opposite direction. In any case, the engaging elements  750 ,  736  are configured, e.g., with suitable sloped surfaces or the like, to become locked or immovable when a compression force exists between the third element  770  and the base element  710 . 
     Turning specifically to  FIG.  33   , the sliding element  740  may include a protrusion  744  configured or adapted to slidably interface with a corresponding recessed portion or groove  736 A along the inner wall of the third element  770 . The protrusion  744  cooperates with recessed portion  736 A such that when the sliding element  740  translates in a proximal direction, in a direction toward proximal end  712  of the intervertebral device for example, the surfaces of the protrusion  744  engage surfaces of the recessed portion  736 A to encourage the third element  770  to move vertically toward the first element  710 . 
     As with vertebral device  500 , in the presence of a lateral force applied to sliding element  740  moving the element  740  toward end  714 , in a ratcheting manner, for example, the engaging elements  750 ,  736  continuously engage and disengage with adjacent opposing engaging elements  750 ,  736 . As the element  740  translates, the third element  770  moves vertically to increase the overall height, H 7 , of the device  700 . With a compression force applied between the third element  770  and the base element  710 , e.g. when the device  700  is positioned between adjacent tissue surfaces, such as two adjacent vertebrae, the engaging elements  750 ,  736  of the sliding element  740  and base element  710 , respectively, engage and prevent the sliding element  740  from further translating. For illustration purposes only, the sliding element  740  of the intervertebral device  700  may be translated through the use of a tool, such as exemplary tool  600  described above with respect to intervertebral device  500 , the distal portion of the sliding element  740  including protrusions and grooves to interface with the tool  600 , for example. 
     Turning to  FIGS.  34  and  35   , the intervertebral device  700  is depicted in cross-section along section A-A of  FIG.  31   . The intervertebral device  700  is depicted in a collapsed configuration in  FIG.  34    and an expanded configuration in  FIG.  35   . In particular, the sliding element  740  includes a device  760  to aide in maintaining contact between the engaging element  750 ,  736  of the sliding element  740  and base element  710 , respectively. The retention device  760  includes the pin  745 A and spring  747 , the spring  747  seated in bore  748 . As depicted, the pin  745 A may extend from a first opening  723  in side portion  716  to a second opening  723  in side portion  718  (not shown), similar to openings  128  of the intervertebral device of  FIG.  1   . The pin  745 A includes a protrusion  762  that extends from a central longitudinal axis of the pin  745 A toward the bottom  720  of the first element  710 . In operation, as the sliding element  740  translates between the two ends  712 ,  714 , the engaging elements  750 ,  736  repeatedly engage and disengage resulting in the sliding element  740  repeatedly moving vertically away from and toward to the bottom portion  720  of the base element  710 , as described above with respect to the intervertebral device  500 . As the sliding element  740  moves away from the base element  710  the ends of the pin  745 A engage the top surfaces of the corresponding openings  723  in respective side portions  716 ,  718 , acting to compress the spring  747 . As the engaging elements  750  of the sliding element  740  pass over the corresponding engaging elements  736  of the base element  710  the spring imparts a force upon the sliding element  740  to encourage re-engagement of the adjacent engaging elements  750 ,  736 . In this way, the engaging elements  750  are biased to remain coupled to corresponding engaging elements  736  during each movement of the sliding element  740 , particularly in a no-load situation, where the force between the third element  770  and the first element  710  is minimal for examples. Accordingly, when a compression force is applied between the top surface  771  of the third element  770  and the bottom surface  720  of the base element  710 , engaging elements  750 ,  736  maintain the current position of all three element  710 ,  740 ,  770  and, ultimately, the current height, H 7 , of the intervertebral device  700 . 
     Turning to  FIG.  36   , a delivery system  800  for positioning and operating intervertebral device  700 , or other intervertebral devices described or contemplated herein, includes an attachment assembly  810  and an expansion tool  860 . The attachment assembly  810  is utilized for attaching the intervertebral device, such as intervertebral device  700 , to the delivery system  800 . The expansion tool  860  is utilized for setting a height of the intervertebral device  700  once the device  700  has been deployed, between adjacent vertebrae for example. Turning to  FIG.  37   , the attachment assembly  810  includes an interface unit  812 , a control assembly  820 , a grasper unit  840 , and an elongate member  814  that extends from the control assembly  820  to the grasper unit  840 . The interface unit  812  is configured to attach the attachment assembly  810  to the expansion tool  860 , as is discussed in greater detail below. The elongate member  814  may include one or more lumens or members therein for controlling the grasper unit  840  or the intervertebral device  700 . 
     Turning to  FIGS.  38 - 41   , operation of the grasper unit  840  will be described in greater detail. The grasper unit  840  includes a housing  842  having first and second slots  842   S1 ,  842   S2 , a control ring  844  operational coupled to first and second arms  846 A,  846 B. The elongate member  814  is fixedly coupled to the housing  842  via pins  815 . An elongate member  816  passes through a lumen of the elongate member  814 , and includes a threaded portion  816 T that is rotationally coupled to threaded portion  844 T of the control ring  844 . Rotational movement of the elongate member  816  is transformed into axial movement of the control ring  844  through treaded portions  816 T,  844 T. First arm  846 A includes first and second protrusions  846 A P1 ,  846 A P2  positioned within slots  842 A S1 ,  842 A S2 , respectively, and a third protrusion  846 A P3  at a distal tip of the arm  846 A. Similarly, second arm  846 B includes first and second protrusions  846 B P1 ,  846 B P2  positioned within slots  842 B S1 ,  842 B S2 , respectively, and a third protrusion  846 B P3  at a distal tip of the arm  846 B. As depicted in  FIG.  38   , arm  846 A includes a raised portion  848 A configured to engage a surface of housing  842 . More specifically, the raised portion  848 A includes a surface  848 A S  configured to engage a surface  843 A S  of the housing. In similar fashion, arm  846 B includes a raised portion  848 B having a surface  848 A S  configured to engage a surface  843 A S  of the housing  842 . Accordingly, as the housing  842  moves distally relative to the arms  846 A,  846 B, a distance between the protrusions  846 A P3 ,  846 B P3  increases. 
       FIGS.  38  and  39    depict the arms  846 A,  846 B in an open configuration, while  FIGS.  40  and  41    depict the arms  846 A,  846 B in a closed configuration, the arms  846 A,  846 B being closer to each other in the open configuration than in the closed configuration. In operation, rotation of the elongate member  816  in a first direction results in axial movement of the control ring  844  as indicated by arrow  816 A. Since the control ring  844  is coupled to the arms  846 A,  846 B, the arms move in the same direction as the control ring, and the surfaces  848 A S ,  848 B S  cooperate with surfaces  843 A S ,  843 B S  of housing  842  to move the arms apart from each other, e.g., transitioning to a closed configuration for example. Continued axial movement of the control ring results in moving the arms  846 A,  846 B axially to clamp onto the proximal features  730 PA and  730 PB. Rotation of the elongate member  816  in a second direction opposite to the first direction, results in axial movement of the control ring  844  in a direction opposite to that indicated by arrow  816 A. As the control ring  844  moves distally with respect to housing  842 , as well as arms  846 A,  846 B, distal surfaces of protrusions  846 A P3 ,  846 B P2  engage or cooperate with distal portions of slots  842   S2  to deflect the arms inward. Accordingly, the more the arms  846 A,  846 B move distally with respect to the housing  842 , the more the distal protrusions  846 A P3 ,  846 B P3  move distally and toward to each other, disengaging from the attachment point, and being free from the profile of the protrusions  730 PA and  730 PB, of the intervertebral device  700 . 
     Turning to  FIGS.  42 A- 42 C , the interaction between the control ring  844 , arms  846 A,  846 B, and the elongate member  816  is depicted. The control ring  844  includes first and second “T” slots  845 , each coupled to a proximal end of one of the arms  846 A,  846 B, as depicted in  FIG.  42 B . The coupling point between the slots  845  and the arms  846 A,  846 B allows for the distal protrusions  846 A P3 ,  846 B P3  to move toward and away from each other to enable a position for coupling between the arms  846 A,  846 B and the intervertebral device  700 .  FIG.  42 C  depicts the control ring  844  rotatably coupled to the elongate tube  816 . 
     Turning to  FIG.  43   , the interface unit  812  is fixedly attached to the control assembly  820 , the control assembly  820  fixedly attached to elongate member  814 . The control assembly  820  includes a rotatable control  824 , a clutch assembly  826 , and a spring  828 . The rotatable control  824  is rotationally attached to a clutch member  826 A, as part of a clutch assembly  826 . A clutch member  826 B is rotationally attached to elongate member  816 . The spring  828  provides a force to encourage coupling between clutch member  826 A and clutch member  826 B at fingers  826 F. The fingers are configured such that rotation of the rotatable control  824  in a first direction results in constant engagement of the fingers, and rotation of the rotatable control  824  in a second direction opposite to the first direction results in the fingers of clutch member  826 A slipping past the fingers of clutch member  826 B once the rotational torque becomes greater than the force applied by the spring  826  on the clutch member  826 A. In this way, rotation of the rotatable control  824  in the second direction results in the arms  846 A,  846 B couplings to the attachment point of the intervertebral device  700 , without over-tightening the connection which may result in undue stress in the delivery system  800  or the intervertebral device  700 , or both. 
     Turning to  FIG.  44   , the expansion tool  860  includes a handle or handle portion  862  and an elongate shaft rotatably coupled to the handle  862 . The expansion tool  860  is utilized for moving the second element, for example the second element  730  of the intervertebral device  700 , along a longitudinal axis of the first element  710  to set a height of the intervertebral device  700  once the device  700  has been deployed, between adjacent vertebrae for example. 
     Turning to  FIGS.  45 A and  45 B , handle portion  862  includes an interface assembly  870  and an attachment control  880 . The interface assembly  870  is configured to attach or interface the handle portion  862  with the attachment assembly  810 . More specifically, the interface assembly  870  interfaces with the interface element  812  of the attachment assembly  810 . The interface assembly  870  includes a pushbutton  872  in a slotted portion  873  of the handle  862 . The pushbutton  872  is biased by a spring  874 , which is positioned within a bore  864  of the handle  862 . With specific reference to  FIG.  45 A , when the pushbutton  872  is depressed, compressing the spring  874 , the interface element  812  of the attachment assembly  810  may be positioned within an opening  866  within the handle  862 . The interface element  812  includes a notch  812 N sized to be equal to or greater than a width of the pushbutton  872 , such that once the interface element  812  is positioned within the opening  866  the pushbutton  872  may be released and a portion  872 A of the pushbutton  872  is positioned within the notch  812 N, as depicted in  FIG.  45 B . 
     Attachment control  880  is utilized to engage the second element, for example element  730 , with the elongate shaft  900 . The control  880  includes a lever  882  rotatably coupled to the shaft  900 , the lever  882  being configured to rotate the shaft to enable engagement of the shaft  900  with the second element  740 . The control  880  may further include a slide lock  884 , which is configured to lock the lever control  882  such that the shaft  900  is maintained in a desired rotational orientation, during operation of an intervertebral device for example. 
     Turning to  FIGS.  46 A and  46 B , a distal end  902  of elongate shaft  900  includes a protrusion  904  adjacent to a groove  906 . The protrusion  904  may be adapted to fit a corresponding groove  740 G at a proximal end of the sliding element  740 . As depicted in  FIG.  46 A , the shaft  900  is angled or rotated along its axis such that the protrusion  904  freely enters the proximal end of the sliding element  740 . Once inserted, the shaft  900  may be rotated, through operation of the attachment control  880  for example, such that the protrusion  904  is positioned within the groove  740 G and held in place through the cooperation of the protrusion  904  and a protrusion  740 P at the proximal end of sliding or third element  740 , as depicted in  FIG.  46 B . 
     The groove  740 G of the sliding element  740  cooperates with the protrusion  904  of the shaft  900  to rigidly attach the shaft  900  to the element  740 . Once the shaft  900  is rigidly attached to the sliding element  740  a user can translate the sliding element  740  through corresponding translation of the shaft. Turning to  FIGS.  47  and  48   , the handle  862  may also include an axial control  890  configured to translate the shaft  900  in proximal and distal directions. The axial control  890  includes a rotational control  892  having threaded portion  894  that interfaces with corresponding threaded portion  862 T of the handle  862 , the axial control  890  being coupled to the shaft  900 . Shaft  900  is axially coupled, not rotationally coupled, to the rotational control  892 . Accordingly, the axial control  890  converts rotational movement of the control  892  into axial movement of the shaft  900 . As the rotational control  892  is rotated in a first direction the control  892  moves distally within the handle portion, which acts to move shaft  900  distally. As the rotational control  892  is rotated in a second direction the control  892  moves proximally within the handle portion, which acts to move shaft  900  proximally. Translation of the shaft  900  results in the translation of the sliding element  740 , further resulting in the sliding element  740  moving between the ends  712 ,  714  of the base member  710 . As the sliding element  740  translates or moves between the ends  712 ,  714 , the element  770  moves in a vertical direction with respect to the base element  710  to change the overall height, H, of the intervertebral device  700 . 
     The intervertebral devices described herein may be made from any suitable biocompatible material, including but not limited to metals, metal alloys (e.g. stainless steel) and polymers (e.g. polycarbonate), and may be formed using any appropriate process, such as screw-machining or molding (e.g. injection molding). The intervertebral devices herein may be sized for minimally invasive procedures having operating lumens at about 12 mm or less. 
     It should be understood that features of any one of the above-described intervertebral devices described herein may be applied to any other of the above-described intervertebral devices, as appropriate. The intervertebral devices described herein may be made from any suitable biocompatible material, including but not limited to metals, metal alloys (e.g. stainless steel) and polymers (e.g., polycarbonate), and may be formed using any appropriate process, such as screw-machining or molding (e.g., injection molding). The intervertebral devices herein may be sized for minimally invasive procedures having operating lumens at about 12 mm or less.