Abstract:
Systems and methods for treating spinal stenosis insert a guide element percutaneously into proximity with the adjacent spinous processes. The systems and methods direct an implant device over the guide element to a position resting between the adjacent spinous processes. The device is sized and configured to distend the adjacent spinous processes. The implant device itself can be variously constructed. It can, e.g., possess threaded lands and/or a notched region in which a spinous process can rest. The implant device has a lumen to accommodate passage of the guide element, so that the device can be passed percutaneously over the guide element for implantation between adjacent spinous processes.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of provisional U.S. Application Ser. No. 60/539,208, filed Jan. 26, 2004, and provisional U.S. Application Ser. No. 60/600,039, filed Aug. 9, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention generally relates to systems and methods for treating conditions of the spine, and, in particular, systems and methods for distending the spine and/or blocking and/or limiting spinal extension for treating, e.g., spinal stenosis.  
       BACKGROUND OF THE INVENTION  
       [0003]     Spinal stenosis is a narrowing of the spinal canal. The narrowing of the spinal canal itself does not usually cause any symptoms. However, symptoms such as pain, weakness, and/or numbness appear when the narrowing leads to compression of the spinal cord and nerve roots. The nerves react by swelling and undergoing inflammation.  
         [0004]     While spinal stenosis can be found in any part of the spine, the lumbar and cervical areas are the most commonly affected. Patients with lumbar spinal stenosis may feel pain, weakness, or numbness in the legs, calves or buttocks. In the lumbar spine, symptoms often increase when walking short distances and decrease when the patient sits, bends forward or lies down. Cervical spinal stenosis may cause similar symptoms in the shoulders, arms, and legs; hand clumsiness and gait and balance disturbances can also occur. In some patients the pain starts in the legs and moves upward to the buttocks; in other patients the pain begins higher in the body and moves downward. The pain may radiate or may be a cramping pain. In severe cases, the pain can be constant, excruciating, and debilitating.  
         [0005]     Some people are born with spinal stenosis. Typically, however, spinal stenosis occurs as the gradual result of aging and “wear and tear” on the spine during everyday activities. The incidence of spinal stenosis increases as people exceed 50 years of age.  
         [0006]     Stenosis can sometimes be treated without surgery, e.g., through the use of medications, steroid injections, rest or restricted activity, or physical therapy. In cases when non-surgical treatments are not effective, surgical treatments can be performed, e.g., decompressive laminectomy, laminotomy, foraminotomy, cervical discectomy and fusion, cervical corpectomy, and laminoplasty. The use of surgically implanted devices that distract the spine, called the X-Bar, has also been advocated, e.g., as disclosed in U.S. Pat. No. 6,451,020.  
         [0007]     These surgical techniques, though effective for many, are invasive. They require exposure of a section of the spine through an open incision, approximately two inches in length, made along the midline of the back, for excision of vertebral lamina or the placement of an implant between adjacent spinous processes. Due to the obvious risks involved, many surgeons will not consider open surgical treatment of spinal stenosis unless several months of non-surgical treatment methods have been tried.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention overcomes the problems and disadvantages associated with current strategies and systems in the treatment of spinal stenosis by invasive, open surgical procedures.  
         [0009]     One aspect of the invention provides systems and methods for treating spinal stenosis. The systems and methods direct an implant device to a position resting between the adjacent spinous processes. The device is sized and configured to distend the adjacent spinous processes. The device can also block or limit extension of the back. The device includes a region that, in use, receives a spinous process. The region tapers from a high surface to a low surface in an anterior-to-posterior direction.  
         [0010]     Other objects, advantages, and embodiments of the invention are set forth in part in the description which follows, and in part, will be obvious from this description, or may be learned from the practice of the invention. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  shows a vertebra with a normal neuroforamen.  
         [0012]      FIG. 2  shows the passage of the spinal cord and nerve roots in a normal neuroforamen.  
         [0013]      FIG. 3  shows a vertebra with a stenotic neuoforamen, i.e., a neuroforamen that has a reduced sized, compared to the neuroforaman shown in  FIG. 1 .  
         [0014]      FIG. 4  shows the narrowing of the spaces in the spine that results in pressure on the spinal cord and/or nerve roots, causing nerves to swell and become inflamed.  
         [0015]      FIG. 5  shows a device that has been implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrae shown in  FIG. 4  to relieve the pressure on the spinal cord and/or nerve roots.  
         [0016]      FIG. 6  shows the device shown in  FIG. 5  as it exists outside the body, prior to implantation.  
         [0017]     FIGS.  7  to  12  show the implantation of the device shown in  FIG. 6  by percutaneous access.  
         [0018]      FIG. 13  shows an alternative embodiment of a device that can be implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrea to relieve the pressure on the spinal cord and/or nerve roots.  
         [0019]     FIGS.  14  to  16  show the implantation of the device shown in  FIG. 13  by percutaneous access.  
         [0020]      FIG. 17  shows the device shown in  FIG. 13  after implantation.  
         [0021]      FIG. 18A  shows an alternative embodiment of a device that can be implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrea to relieve the pressure on the spinal cord and/or nerve roots.  
         [0022]      FIG. 18B  is a section view of the device taken generally along line  18 B- 18 B in  FIG. 18A .  
         [0023]      FIG. 19  shows the implantation of the device shown in  FIG. 18A  by percutaneous access.  
         [0024]      FIG. 20  shows the device shown in  FIG. 18A  after implantation.  
         [0025]      FIG. 21  is a section view of the device taken generally along line  21 - 21  in  FIG. 20 .  
         [0026]      FIGS. 22A and 22B  are perspective views of an alternative embodiment of a device that can be implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrea to relieve the pressure on the spinal cord and/or nerve roots and having a hinge mechanism and in which the angle of the inclined planes may be controlled by a series of screws and bores.  
         [0027]      FIG. 23  is a side view of the device of  FIGS. 22A and 22B  implanted between adjacent first and second spinous processes of the stenotic vertebrae and in a contracted condition.  
         [0028]      FIG. 24  is a side view similar to  FIG. 23  and illustrating the device in an enlarged condition which relieves pressure on the spinal cord and/or nerve roots.  
         [0029]      FIG. 25  is a top plan view of the bottom arm of the device of  FIGS. 22A and 22B  illustrating a configuration and placement of screws and bores which serves to raise the incline planes of the device upon insertion of the screws into the bores.  
         [0030]      FIG. 26  is a view similar to  FIG. 25  and illustrating an alternative configuration and placement of screws and bores.  
         [0031]      FIG. 27  is a perspective view illustrating the device of  FIGS. 22A and 22B  implanted between adjacent first and second spinous processes after insertion of screws into the bores and the incline planes raised.  
         [0032]      FIG. 28  is a view similar to  FIG. 25  and illustrating another alternative configuration and placement of screws and bores.  
         [0033]      FIG. 29  is a view similar to  FIG. 25  and illustrating another alternative configuration and placement of screws and bores.  
         [0034]      FIG. 30  is a side view of an alternative embodiment of a device that can be implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrea to relieve the pressure on the spinal cord and/or nerve roots and having a hinged mechanism and in which the angle of the inclined planes may be controlled by an enlargeable bladder.  
         [0035]      FIG. 31  is an alternative embodiment of the device of  FIG. 30 .  
         [0036]      FIG. 32  is a bottom plan view of the upper arm of an alternative embodiment of the device of  FIG. 30  having left and right bladders.  
         [0037]      FIG. 33  is a bottom plan view of the upper arm of an alternative embodiment of the device of  FIG. 30  having anterior and posterior bladders. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]      FIG. 1  shows a vertebra with a normal neuroforamen.  FIG. 2  shows the passage of the spinal cord and nerve roots in a normal neuroforamen.  
         [0039]      FIG. 3  shows a vertebra with a stenotic neuoforamen, i.e., a neuroforamen that has a reduced sized, compared to the neuroforaman shown in  FIG. 1 . As  FIG. 4  shows, the narrowing of the spaces in the spine that results in pressure on the spinal cord and/or nerve roots. When the neuroforamina are reduced in size, the nerves may swell and become inflamed, causing pain and discomfort.  
         [0040]      FIG. 5  shows a device  10  that has been implanted by percutaneous access between adjacent first and second spinous processes of the stenotic vertebrea shown in  FIG. 4 . The device  10  relieves the pressure on the spinal cord and/or nerve roots.  FIG. 6  shows the device  10  as it exists outside the body, prior to implantation. The device  10  can be made of a durable prosthetic material, such as, e.g., polyethylene, rubber, a sponge material (e.g., polyethylene sponge), tantalum, titanium, chrome cobalt, surgical steel, bony in-growth material, ceramic, artificial bone, or a combination thereof.  
         [0041]     The implanted device  10  includes a body  12  having a contact region  14  that, in use, rests between the first and second spinous processes (see  FIG. 12 ). As  FIG. 12  best shows, the region  14 , in use, engages both spinous processes to apply a separating force. The force spreads apart or distracts the spinous processes.  
         [0042]     The degree of distraction can be seen by comparing  FIG. 5  (with distraction) with  FIG. 4  (before distraction). The distraction enlarges the volume of the spinal canal to alleviate pressure on blood vessels and/or nerves, thereby treating the pain and other symptoms that can accompany spinal stenosis.  
         [0043]     In use, the implanted device  10  also serves as an extension stop for the back. As the back is bent backwardly and placed in extension, the presence of the implanted device  10  resists extension beyond a given point. Due to the presence of the implanted device  10 , the spacing between adjacent spinous processes cannot be reduced to less than the outside diameter. of the body region  14 . Typically, given an outside diameter of between 5 mm to 14 mm, the presence of the implanted device  10  can serve to block the last 4° to 5° of extension. Pressure on nerves and the resulting pain are therefore alleviated or reduced.  
         [0044]     Significantly, the device  10  can be implanted by non-invasive percutaneous access, instead of requiring an open surgical procedure. As  FIG. 7  shows, a small incision, e.g., 1 cm, is desirably made about 8 cm to 10 cm from the midline of the back. With reference to  FIG. 8 , a guide pin  16  is inserted through the incision. Under imaging guidance (e.g., x-ray (fluoroscopy), ultrasound, magnetic resonance, computed tomography, or combinations thereof) the guide pin  16  is inserted in between the adjacent spinous processes.  
         [0045]     A first tubular obturator  18  is inserted over the guide pin  16  under imaging guidance into the space between the two spinous process (see  FIG. 9 ). The outside diameter of the obturator  18  is selected to initiate distension of the spinous processes.  
         [0046]     The first tubular obturator  18  is withdrawn over the guide pin  16 , and a second tubular obturator  20  is inserted over the guide pin  16  under imaging guidance into the previously distended space between the spinous processes (see  FIG. 10 ). The second tubular obturator  20  has a second outside diameter greater than the outside diameter of the first obturator  18 , to open a greater distention of the spinous processes. This distension is slightly smaller than the outside diameter of the body region  14  of the device  10  to be implanted. The second obturator  20  is then withdrawn over the guide pin  16 . Additional (or fewer) obturators may be deployed in this manner until a. desired degree of distension is achieved.  
         [0047]     The device  10  is now inserted over the guide pin  16  under imaging guidance into the distended space between the spinous processes ( FIG. 11 ). As  FIG. 6  shows, the body  12  of the device  10  includes an interior lumen  22  to accommodate its passage over the guide pin  16 .  
         [0048]     The body  12  of the device  10  can be sized and configured in various ways. The body  12  can, e.g., be cylindrical, square, rectangular, or curvilinear (banana-shaped). The body  12  also desirably includes threaded lands  24 , so that the device  10  functions as a screw. A screw driving tool  26  passes over the guide pin  16  and engages the device  10  ( FIG. 11 ), to rotate the device  10  about the guide pin  16  and advance the device  10  between the spinous processes. The threaded lands  24  take purchase in the bone of the spinous processes, to secure the device  10  in place between the distended spinous processes.  
         [0049]     The tool  26  and guide pin  16  can now be withdrawn, leaving the implanted device  10  behind ( FIG. 12 ). The incision is closed. The implantation of the device  10  has been completed percutaneously and without need of an open surgical procedure.  
         [0050]      FIG. 13  shows an alternative embodiment of a device  28  that can be implanted by percutaneous access to cause distention between adjacent first and second spinous processes of stenotic vertebrea. The device  28  includes a blunt nose  29  and a bullet-shaped body  30  having a stepped-down or notched region  32  between adjoining stepped-up or ridge regions  34 . Desirably, the interior of the notched region  32  includes grooves, lands, or an otherwise roughened exterior surface to gain purchase in bone.  
         [0051]     Like the body  12 , the body  30  can be made of a durable prosthetic material, such as, e.g., polyethylene, rubber, a sponge material (e.g., polyethylene sponge), tantalum, titanium, chrome cobalt, surgical steel, bony in-growth material, ceramic, artificial bone, or a combination thereof. Also like the body  12 , the body  30  includes a lumen  36  to accommodate passage of a guide pin  16 , as will be described in greater detail later.  
         [0052]     In a typical embodiment, the body  30  measures about 9 mm in overall length, and the regions  32  and  34  are approximately equal in length (i.e., each being approximately 3 mm in length). The outside diameter of the body  30  at the ridge regions  34  can be about 5 mm to 6 mm. The depth of the notched region  32  can be about 2 mm. If desired, there can be two, oppositely facing notched regions  32  (not shown).  
         [0053]     As  FIG. 14  shows, the device  28  is desirably implanted using a tool  40  that comprises a sleeve  42  carried at the end of a handle  38  and a pusher  44  that entends through the handle  38  into the sleeve  42 . The sleeve  42  accommodates insertion of the device  28 , with its blunt distal end partially exposed. The pusher  44  serves, in use, to push against the proximal end of the device  28  within the sleeve  42 , to expel the device  28  from the sleeve  42 . The proximal end of the body  30  desirably includes a receptacle  46  in which the pusher  44 , when in use, rests. The pusher  44  includes a lumen  48  that accommodates passage of a guide pin  16 , so the tool  40 , like the device  28  can be percutaneously deployed.  
         [0054]     In use, the guide pin  16  and obturators  18  and  20  are manipulated under imaging guidance as previously described and shown in FIGS.  7  to  10 . At this point in the procedure (see  FIG. 15 ), the tool  40 , carrying the device  28  (the device  28  being preferably retracted, at least in part, within the sleeve  42 ), is deployed over the guide pin  16  to a location adjacent the distended spinous processes. The pusher  44  is advanced forward (see  FIG. 16 ), to expel the device  28  from the sleeve  42 . The blunt distal end of the body  30  enters the distended space between the processes, distending them slightly more, until one of the spinous processes settles within the notched region  32 (see  FIG. 17 ) (if two notched regions are present, both spinous processes will settle into its own notched region). The tool  40  is withdrawn back over the guide pin  16 . The guide pin  16  is removed, leaving the device  28  resting between the two spinous processes. The incision is closed. The percutaneous implantation of the device  28  has been completed.  
         [0055]      FIGS. 18A and 18B  show an alternative embodiment of the device  28 . Structural elements that are shared with the device  28  shown in FIGS.  13  are designated by the same reference numbers. In  FIGS. 18A and 18B , the device  28  includes a notched region  50 , where the spinous process rests when the device  28  is installed. Unlike the notched region  32  in  FIG. 13 , the notched region  50  is tapered between a high surface  52  and a low surface  54 . In a representative embodiment, the taper forms an angle α (shown in  FIGS. 18A and 18B ) that is in the range of 4-degrees to 25-degrees from horizonal, which is gauged relative to the anterior-to-posterior orientation of the receptacle  46 . If desired, there can be two, oppositely facing notched tapered notched regions  32  (not shown). As with the notched region  32 , the interior of the notched region  50  can include grooves, lands, or otherwise roughened exterior surface to gain purchase in bone.  
         [0056]     In use, the device  28  is installed between adjacent first and second spinous processes of stenotic vertebrae (see  FIG. 20 ), such that the high surface  52  is oriented in an anterior direction—i.e., adjacent the disc—and the low surface  54  is oriented in a posterior direction—i.e., facing away from the vertebral body (see  FIG. 21 , also).  
         [0057]     The taper angle α of the notched region  50  is preferably selected to approximate the degree of the posterior curvature of the spinous process that settles within the notched region  50 , to maximize contact between the notched region  50  and the spinous process throughout the notched region  50 . The degree of taper may be chosen to accommodate a specific location and/or individual anatomy. The inferior side of the device  28  can also be notched in the same manner with a posterior-directed taper  52 , so that spinous processes will settle into the superior and interior notched regions  50 .  
         [0058]     To install, the guide pin  16  and obturators  18  and  20  are manipulated under imaging guidance as previously described and shown in FIGS.  7  to  10 . The tool  40 , carrying the device  28  (the device  28  being preferably retracted, at least in part, within the sleeve  42 ), is deployed over the guide pin  16  to a location adjacent the distended spinous processes such that the tapered region  50  is oriented with the high surface  52  directed anteriorly and the low surface  54  directed posteriorly, as shown in  FIG. 19 . The pusher  44  is then advanced forward to expel the device  28  from the sleeve  42 , as previously described.  
         [0059]     The blunt distal end  29  of the body  30  enters the distended space between the processes, distending them slightly more, until one (or both, depending upon the configuration) of the spinous processes settles within the notched region  50 , as shown in  FIGS. 20 and 21 .  
         [0060]     Distraction of stenotic vertebrae may also be accomplished by placement of an enlargeable or expandable structure between adjacent first and second spinous processes. The enlargeable structure may be selectively manipulated between a contracted condition suitable for percutaneous introduction between the spinous processes and an expanded or enlarged condition in which the expandable structure engages both spinous processes to apply a separating force to spread apart or distract the spinous processes. The enlargeable structure may take various configurations suitable for percutaneous access and providing suitable distraction. By way of example and not limitation, a representative embodiment will now be described.  
         [0061]      FIG. 22A  shows a device  100  suitable for non-invasive insertion by percutaneous access and without requiring an open surgical procedure. The device  100  provides a hinged arrangement that permits selective expansion of the device  100  to allow adjustment of incline planes to the desired angle for each interspinous process. The device  100  has a contracted condition, shown in  FIG. 23 , suitable for percutaneous insertion between adjacent spinous processes and an expanded condition, shown in  FIG. 24 , in which the device  100  engages both spinous processes to apply a separating force to spread apart or distract the spinous processes.  
         [0062]     As  FIGS. 22A  shows, the device  100  comprises a hinge  102 , a top or first arm  104  and a bottom or second arm  106 . The arms  104  and  106  define an angle of taper (β). The arms may be selectively expanded to increase the angle β to a desired angle to accommodate the angle of adjacent spinous processes at a given location on the spinal column and to accommodate individual anatomy.  
         [0063]     With reference to  FIG. 23 , the device  100  is introduced in the contracted condition between adjacent first and second spinous processes of stenotic vertebrae such that the arms  104  and  106  are oriented in an anterior direction, i.e., adjacent the disc, and the hinge  102  is oriented in a posterior direction, i.e., facing away from the vertebral body.  
         [0064]     As best seen in  FIG. 24 , the first arm  104  provides a first contact surface  108  that, upon expansion, engages the first spinous process. The second arm  106  provides a second contact surface  110  that, upon expansion, engages the second spinous process. The contact surfaces  108  and  110  may be essentially smooth, as seen in  FIG. 22A . Alternatively, either or both of the contact surfaces  108  and  110  may be roughened or saw-toothed to provide a series of projections  111  in a manner that prevents slippage of the device, as seen in  FIG. 22B . The projections  111  may take any of a variety of configurations (e.g., ridges, teeth). It is contemplated that the number, size, and configuration of the projections  111  may be varied as desired or as necessary to prevent slippage.  
         [0065]     The device  100  can be made of a durable prosthetic material, such as, e.g., polyethylene, rubber, a sponge material (e.g., polyethylene sponge), tantalum, titanium, chrome cobalt, surgical steel, bony in-growth material, ceramic, artificial bone, or a combination thereof.  
         [0066]     The device  100  may be inserted by percutaneous access as previously described and using suitable surgical tools.  
         [0067]     In use, the implanted device  100  also serves as an extension stop for the back and can serve to block the last 4° to 5°. Due to the presence of the implanted device  100 , the spacing between adjacent spinous processes cannot be reduced to less than angle β. Pressure on nerves and the resulting pain are therefore alleviated or reduced.  
         [0068]     A series of complementary and mating fixation members, e.g., screws, and fixation member receivers, e.g., holes or bores, allow for controlled expansion and independent right and left side adjustment to achieve desired inclined planes and thereby create the desired angle β for each interspinous process.  
         [0069]     In a representative embodiment illustrated in  FIG. 25 , a first bore  112 A extends in a lateral direction across the spinous processes (i.e., along an axis A and at approximately a 90-degree angle from the axis B of the device  100 ) from a first side  114  (i.e., the right side in  FIG. 25 ) to a second side  116  (i.e, the left side in  FIG. 25 ) of the device  100  and is of an essentially constant diameter (D 1 ). The first bore  112 A receives a first screw  118 A, e.g., by threaded engagement. The first screw has a body  120 A that tapers medially from the first side  114  to the second side  116  from a larger diameter D 2  to a smaller diameter D 3 . D 2  is greater than D 1  (D 2 &gt;D 1 ) such that, upon insertion into the first bore  112 A, the first screw  112 A raises the first side  114  (i.e., the side of insertion) of the inclined plane formed by the first and second arms  104  and  106  (see also  FIG. 27 ).  
         [0070]     A second bore  112 B extends in a lateral direction and tapers in diameter medially from a larger diameter D 4  to a smaller diameter D 5 . The second bore  112 B receives a second screw  118 B e.g., by threaded engagement. The second screw  118 B has a body  120 B of an essentially constant diameter (D 6 ). D 6  is greater than D 5  (D 6 &gt;D 5 ), such that upon insertion into the second bore  112 B, the second screw  118 B raises the second (i.e., opposing) side  116  of the inclined plane formed by the first and second arms  104  and  106 .  
         [0071]     The screws may be formed of any suitable durable and biocompatible material, e.g., titanium, titanium alloys, tantalum, chrome cobalt, surgical steel, ceramic, sintered glass, artificial bone, or combinations thereof.  
         [0072]     The size as well as the depth of insertion of the screws  118 A and  118 B can be selectively controlled to achieve the desired incline plane for a given location on the spinal column and to accommodate individual anatomy.  
         [0073]     In a representative embodiment, the range of incline plane is adjustable from approximately 4-degrees to approximately 25-degrees from horizontal, which is gauged relative to the anterior-to-posterior orientation of the device  100 .  
         [0074]     In this arrangement, the first and second screws  118 A and  118 B are inserted from the same side  114 . In the embodiment illustrated in  FIG. 25 , both screws are inserted from the right or first side  114  such that the first screw  118 A raises right side and the second screw  118 B raises left or second side  116 .  
         [0075]     Alternatively, both the first and second screws  118 A and  118 B may be inserted from the opposing or left side  116 , as shown in  FIG. 26 . In this embodiment, the first screw  118 A raises the second or left side  116 , while the second screw  118 B raises the first or right side  114 .  
         [0076]     In alternative embodiments, the first and second screws are inserted from opposite sides  114  and  116  respectively. In one embodiment, illustrated in  FIG. 28 , both the first and second bores  112 A and  112 B extend in a lateral direction and are of an essentially constant diameter D 1  such that the bores  112 A and  112 B are generally parallel. The bodies  120 A and  120 B of the first and second screws  118 A and  118 B, respectively, taper medially from a larger diameter D 2  to a smaller diameter D 3 . The first screw  118 A is inserted from the first side  114  to raise the first side  114 . The second screw  118 B is inserted from the second side  116  to raise the second side  116 .  
         [0077]     In another embodiment, illustrated in  FIG. 29 , both of the first and second bores  112 A and  112 B extend in a lateral direction and taper in diameter medially from a larger diameter D 4  to a smaller diameter D 5 . The first bore  112 A tapers medially from the first side  114  toward the second side  116 . The second bore  112 B tapers medially from the second side  116  toward the first side  114 . Both of the first and second screws  118 A and  118 B have a body  120 A and  120 B, respectively, of an essentially constant diameter D 6 . The first screw  118 A is inserted from the first side  114  to raise the second (i.e., opposite) side  116 . The second screw  118 B is inserted the second side  116  to raise the first (i.e., opposite) side  114 .  
         [0078]     It will be readily apparent to one of skill in the art in view of this disclosure that the number, configuration, and placement of screws  118  and bores  112  may be varied to accommodate specific needs as well as to accommodate individual anatomy.  
         [0079]     In other alternative embodiments, an enlargeable container is used to displace or raise the arms  104  and  106  and thereby increase the inclined planes to the desired angle β. For example,  FIG. 30  illustrates an alternative embodiment of a device  200  suitable for non-invasive insertion by percutaneous access and without requiring an open surgical procedure. The device  200  has a hinged arrangement and shares features of the device  100  previously described. Therefore, like reference numbers will be assigned to denote like parts.  
         [0080]     In the illustrated embodiment, a bladder  202  may be inserted between the arms  104  and  106  and expanded or inflated, e.g., by bone cement, to raise the arms  104  and  106  to the desired inclined planes. The bladder  202  may be formed integral with the device  202 . The device  200  is inserted between adjacent spinous processes as previously described with the bladder  202  in the contracted condition. As shown in  FIG. 30 , the bladder  202  may include an injection port  204  for introducing bone cement or other medium into the bladder  202  to enlarge the bladder  202 . The degree of expansion of the bladder  202  may be selectively controlled and is desirably uniform in the medial-lateral direction to provide equivalent right and left side distraction. In another embodiment, illustrated in  FIG. 31 , the arm  104  includes an inflation port  204  that communicates with the bladder  202  through a lumen  206  to permit introduction of a medium into the bladder  202 .  
         [0081]     Alternatively, the bladder  202  may be a separate component from the device  200 . In this arrangement, the device  202  is first inserted between adjacent spinous processes as previously described. The bladder  202  is then inserted in the contracted condition and positioned between arms  104  and  106 . A medium is then injected or otherwise introduced into the bladder  202  to enlarge the bladder  202 , as previously described.  
         [0082]     It is contemplated that multiple bladders  202  can be used, e.g., left and right bladders  202  ( FIG. 32 ), or anterior and posterior bladders ( FIG. 33 ). Desirably, the bladders  202  may be enlarged independently, e.g. by distinct inflation ports  204 , to selectively control the degree of enlargement of each bladder  202  to produce the desired angle β. It is further contemplated that the bladders  202  may be of varying size and configuration as desired to accommodate specific needs and individual anatomy.  
         [0083]     Other embodiments and uses of the inventions described herein will be apparent to those skilled in the art from consideration of the specification and practice of the inventions disclosed. All documents referenced herein are specifically and entirely incorporated by reference. The specification should be considered exemplary only with the true scope and spirit of the invention indicated by the following claims. As will be easily understood by those of ordinary skill in the art, variations and modifications of each of the disclosed embodiments can be easily made within the scope of this invention as defined by the following claims.