Patent Publication Number: US-2011054533-A1

Title: Spinous fusion device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/237,280, entitled “Spinous Fusion Device Made From Human Femur,” and filed on Aug. 26, 2009, which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The central nervous system is part of an overall system that functions to coordinate human activity. It is made up of the brain and the spinal cord. The main function of the spinal cord is to act as a conduit to communicate neuronal signals from the brain to the rest of the body. Protecting the spinal cord is the spinal column, or what is commonly referred to as the spine or vertebral column. Anatomically, the spinal column is made up of several regions, including the cervical, thoracic, lumbar and sacral regions. The cervical spine is made up of seven vertebrae, and the cervical spine functions to support the weight of the head. The thoracic spine is made up of twelve vertebrae, and the thoracic spine functions to protect the organs located within the chest. Five vertebrae make up the lumbar spine. The lumbar spine contains the largest vertebrae, and the lumbar spine functions as the main weight bearing portion of the spine. Located at the base of the spine are the five fused vertebrae known as the sacrum. The coccyx sits at the base of the spinal column and consists of four fused vertebrae. 
     Each of the vertebrae associated with the various spinal cord regions is made up of a vertebral body, a posterior arch, and transverse processes. The vertebral body, often described as having a drum-like shape, is designed to bear weight and withstand compression or loading. In between the vertebral bodies are intervertebral discs. The discs help cushion the spine against various movements and can be the source of various diseases. The posterior arch of the vertebrae is made up of the lamina, pedicles, and facet joints. Transverse processes extend outwardly from the vertebrae and provide the means for muscle and ligament attachment, which aid in movement and stabilization of the vertebra. 
     One of the more common ailments associated with the spinal cord is damage to the spinal discs. Damage to the discs results from physical injury, disease, genetic disposition, or as part of the natural aging process. Disc damage often results in intervertebral spacing not being maintained, causing pinching of exiting nerve roots between the discs, resulting in pain. For example, disc herniation is a condition in which the disc material bulges from the disc space between the two vertebrae bodies. It is the bulging of the disc material which causes impingement on the nerves, manifesting in pain to the patient. In severe cases or in cases which have developed into spinal instability, the damaged disc material between the vertebral bodies is removed and replaced with spinal stabilization implants. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the figures. 
         FIG. 1  is a frontal view of a human skeleton. 
         FIG. 2  is a side view of a femur section cut away from the femur of the human skeleton depicted in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the human femur shaft depicted in  FIG. 2 . 
         FIG. 4  is a perspective view of the femur section depicted in  FIG. 2 . 
         FIG. 5  is a side view of the femur section depicted in  FIG. 2  showing the shape of an exemplary implant device projected on the outer surface in accordance with an embodiment of the present disclosure. 
         FIG. 6  is a perspective view of the femur section of  FIG. 2  showing the shape of the implant device projected on the outer surface. 
         FIG. 7  is a side view of the femur section of  FIG. 2  showing the shape of another exemplary implant device projected on the outer surface in accordance with an embodiment of the present disclosure. 
         FIG. 8  is a cross-sectional view of the femur section of  FIG. 2  taken along line B-B showing the hatched region that remains once the unnecessary portions of the femur are cut away from the implant device. 
         FIG. 9  is a cross-sectional view of the femur section of  FIG. 2  taken along line B-B showing the hatched region that is to be cut away from the implant device. 
         FIG. 10  is a front view of an exemplary implant device that results from the cutting away of the unnecessary portions of the femur. 
         FIG. 11  is a cross sectional view of the implant device, such as is depicted in 
         FIG. 10 , taken along line C-C. 
         FIG. 12  is a side view of the implant device, such as is depicted in  FIG. 10 . 
         FIG. 13  is a front perspective view of the implant device, such as is depicted in  FIG. 10 . 
         FIG. 14  is a back perspective view of the implant device, such as is depicted in 
         FIG. 10 . 
         FIG. 15  is a lateral view of a functional spinal unit. 
         FIG. 16  is a posterior view of the functional spinal unit, such as is depicted in  FIG. 15 . 
         FIG. 17  is a lateral view of the functional spinal unit, such as is depicted in  FIG. 15  having the implant device, such as is depicted in  FIG. 10 , inserted within the functional spinal unit. 
         FIG. 18  is a posterior view of the functional spinal unit, such as is depicted in  FIG. 16 , having the implant device, such as is depicted in  FIG. 10 , inserted within the functional spinal unit. 
         FIG. 19  is a perspective view of the functional spinal unit, such as is depicted in  FIG. 15 . 
         FIG. 20  is a perspective view of the functional spinal unit, such as is depicted in  FIG. 15 , having the implant device, such as is depicted in  FIG. 10 , inserted within the functional spinal unit. 
         FIG. 21  is a flowchart depicting a method of making the spinal implant device, such as is depicted in  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
     An implant device in accordance with an embodiment of the present disclosure is designed for insertion between bone structures. In particular, the implant device is designed for insertion between two spinous processes. The implant device prevents or limits the motion of the vertebrae. 
     In one embodiment, the implant device is made from a femur section of a skeleton. In this regard, a femur section is cut from the femur of a skeleton, and portions of the femur section are cut away leaving only the implant device. 
     The implant device is arch-shaped and has at least two opposing notches on a top side and a bottom side for mating with the spinous process. In one embodiment, the implant device further has two opposing notches on the sides for receiving an insertion instrument when the implant device is being inserted. 
       FIG. 1  is a frontal view of a human skeleton. The human skeleton has a femur  1  that is located between a pelvic girdle  20  and a tibia  21 . In accordance with an embodiment of the present disclosure, a femur section  22  is cut from the femur  1 . 
       FIG. 2  is a side view of the femur section  22  that is cut from the femur  1  of the human skeleton depicted in  FIG. 1 . Note that the top and bottom sides  28  and  29 , respectively, are machined when the cut is made in the femur  1 . 
       FIG. 3  is a cross-sectional view of the femur  1  taken along line A-A of  FIG. 2 . The femur section  22  has an intermedullary canal  4 , which is a hollow opening that extends through the femur section  22 . In addition, the femur section  22  has an outer wall  2 , an inner wall  3 , and a machined surface  5 . Note that  FIG. 3  shows only one view taken along A-A. However, a view in the opposing direction is substantially similar. 
       FIG. 4  is a perspective view of the femur section  22 . As indicated hereinabove, the femur section  22  has an intermedullary canal  4 , which is a hollow opening that extends through the femur section  22 . In addition, the femur section  22  has the outer wall  2 , the inner wall  3 , and the machined surface  5 . 
     In the process of making an exemplary implant device (not shown) in accordance with an embodiment of the present disclosure, unneeded portions of the femur section  22  are cut away leaving only the implant device. In this regard,  FIG. 5  is a front view showing the location and orientation of a projection onto the outer surface  2  of an outline  50  of the implant device that is to be cut away from the femur section  22 . Further,  FIG. 6  is a perspective view showing the location and orientation of the projection of the outline  50  onto the outer surface  2  of the implant device that is to be cut away from the femur section  22 . 
     With reference to  FIG. 5 , the projection depicts a top side  34  of the implant device having a notch  36  therein. In addition, the projection depicts a bottom side  35  of the implant device having a notch  37  therein. Further, sides  30  and  31  also having notches  32  and  33 , respectively, therein. 
       FIG. 7  is a front view showing the location and orientation of a different projection onto the outer surface  2  of an outline  60  of another exemplary implant device that is to be cut away from the femur section  22 . The projection of the outline  60  in  FIG. 7  differs from the projection in  FIG. 5  in that there are no notches located on the sides  38  and  39  of the projection. 
       FIG. 8  shows a cross-sectional view of the femur section  22  taken along line B-B in  FIG. 5 . The cross-sectional view shows an exemplary implant device  6  (shown in the hatched section) that remains after the unneeded portion  7  of the femur section  22  is cut away. The implant device  6  has a front surface  41  that is made up of the outer wall  2  of the femur section  22 . In addition, the implant device  6  has a back surface  42  that is partially made up of the inner wall  3 . The intermedullary canal  4  creates an arch-shaped portion  43  on the back surface  42 .  FIG. 9  shows the cross-sectional view of the femur section  22  with the unneeded portion  7  (shown in the hatched section) that is to be removed. 
     Note that as described herein, the implant device  6  is made of human allograft. However, the implant device  6  may be made of other materials known in the art or future-developed. For example, the implant device  6  may be made from a synthetic implant grade polymer, such as PEEK or Polyethylene 
       FIG. 10  is a front view of the device  6 . The device  6  comprises the top side  34  that has the notch  36  formed therein, and the device  6  comprises the bottom side  35  that has the notch  37  formed therein. The notches  36  and  37  in the top and bottom sides  36  and  37 , respectively, are formed therein for receiving spinous processes, which is described herein with reference to  FIG. 18 . 
     The notch  36  has tapered walls  50  and  51  for receiving a spinous process, and the notch  37  has tapered walls  52  and  53  for receiving another spinous process. In one embodiment, the walls  50  and  51  have width w 1  at the bottom of the notch  36  that increases to width w 2  at the top of the notch  36 . Further, the walls  52  and  53  are dimensioned substantially similar to the walls  50  and  51 . In another embodiment, the walls  50  and  51  have a width w 1  at the bottom of the notch  36  that decreases to width w 2  at the top of the notch  36 . In such an embodiment, the walls  52  and  53  are dimensioned substantially similar to the walls  50  and  51 . 
     In addition, the device  6  comprises the sides  30  and  31 . In one embodiment, the side  30  has the notch  32  formed therein, and the side  31  has the notch  33  formed therein. Notably, such notches  32  and  33  are for receiving an insertion tool when the device  6  is being implanted within a functional spinal unit, which is described further herein with reference to  FIGS. 15-20 . Note that the notches  32  and  33  are not necessary in other embodiments of the present disclosure, such as the embodiment depicted in  FIG. 7 . 
       FIG. 11  is a cross-sectional view of the device  6  taken along line C-C in  FIG. 10 . As described hereinabove, the device  6  has the front surface  41  that is arch-shaped and which is formed from the outer wall  2  ( FIG. 6 ) of the femur section  22  ( FIG. 6 ). Additionally, the device  6  has a back surface  42  that has an arch portion  43 . The arch portion  43  is formed by the inner wall  3  ( FIG. 6 ) of the femur section  22 . The remaining back surface  42  is formed when the unneeded portion  7  ( FIG. 8 ) of the femur  22  ( FIG. 8 ) is cut away from the device  6 . In another embodiment, the front surface  41  and the arch portion  43  of the back surface  42  only approximate the outer wall  2  and the inner wall  3 , respectively. 
       FIG. 12  is a side view of the device  6 . The side view of the device  6  depicts the notch  33  that is formed in the side  31 . In addition, the side view depicts the arched characteristic of the front surface  41 . Further, the device  6  comprises a machined surface  10  that is cut so as to minimize sharp corners on the implant device  6 . 
       FIG. 13  is a perspective view of the device  6 . The device  6  comprises on the top side  34  the notch  36  for receiving a spinous process, which is described further with reference to  FIG. 18 . In addition, the device  6  comprises the sides  30  and  31  having notches  32  and  33 , respectively, for receiving an insertion tool for inserting the implant device  6  into a functional spinal unit. 
     As indicated hereinabove, the front surface  41  is formed by the outer wall  2  ( FIG. 6 ) of the femur section  22  ( FIG. 6 ). Additionally, the back surface  42  is partially formed by the inner wall  3  ( FIG. 6 ) of the femur section  22 . 
       FIG. 14  is a perspective view of the device  6 . The device  6  comprises the front surface  41  and the back surface  42 . The back surface  42  is partially made up of the arched portion  43  that is formed by the inner wall  3  ( FIG. 6 ) of the femur section  22  ( FIG. 6 ). In addition, the back surface  43  comprises machined surface  11  that are formed when the unneeded portion  7  ( FIG. 8 ) is cut away from the implant device  6 . 
     The device  6  further has the sides  30  and  31 . Side  30  has the notch  32 , and side  31  has the notch  33 . The notches  32  and  33  are for receiving an insertion tool. 
     The device further has the top side  34  and bottom side  35 . The top side  34  comprises the notch  36  for receiving a spinous process, described further with reference to  FIG. 18 . Further, the bottom side  35  comprises the notch  37  for receiving a spinous process, described further with reference to  FIG. 18   
       FIG. 15  is a side view of a functional spinal unit  60 . The functional spinal unit  60  comprises a superior vertebral body  12  and corresponding spinous process  15 . In addition, the functional spinal unit  60  comprises an inferior vertebral body  13  and corresponding spinous process  16 . Further, a disc  14  is interposed between the superior vertebral body  12  and the inferior vertebral body  13 . There is also an interspinous space  17  in which the implant device  6  ( FIG. 10 ) can be inserted. 
       FIG. 16  is a posterior view of the functional spinal unit  60 . As described hereinabove, the functional spinal unit  60  comprises the superior vertebral body  12  and corresponding spinous process  15 . In addition, the functional spinal unit comprises the inferior vertebral body  13  and corresponding spinous process  16 . Between the spinous process  15  and the spinous process  16  is the interspinous space  17  in which the implant device  6  can be inserted. 
       FIG. 17  is a lateral view of the functional spinal unit  60  having the implant device  6  inserted therein. In this regard, the implant device  6  is seated between the spinous process  15  and the spinous process  16 . Seating the implant device in the interspinous space  17  in such a manner separates the superior vertebral body  12  from the inferior vertebral body  13  so that the disc  14  is relieved from pinching that may occur due to an ailment. 
       FIG. 18  is a posterior view of a functional spinal unit  60 . The functional spinal unit  60  comprises the superior vertebral body  12  and corresponding spinous process  15  and the inferior vertebral body  13  and corresponding spinous process  16 . The implant device  6  is seated within the interspinous space  17  ( FIG. 17 ) such that the notch  36  receives the spinous process  15  and the notch  37  receives the spinous process  16 . 
       FIG. 19  is a perspective view of the functional spinal unit  60 . The functional spinal unit  60  comprises the superior vertebral body  12  and corresponding spinous process  15 . In addition, the functional spinal unit  60  comprises the inferior vertebral body  13  and corresponding spinous process  16 . Between the superior vertebral body  12  and the inferior vertebral body  13  is the disc  14 . Between the spinous process  14  and the spinous process  15  is the interspinous space  17 . 
       FIG. 20  is a perspective view of a functional spinal unit  60  wherein the implant device  6  is inserted. The implant device  6  is inserted such that the notch  36  receives the spinous process  15  and the notch  37  receives the spinous process  16 . 
       FIG. 21  is a flowchart depicting a method of making the spinal implant device  6  depicted in  FIG. 13 . 
     The first step in the method is sectioning a human femur  1  ( FIG. 1 ) into a femur section  22  ( FIG. 2 ). The second step in the method is cutting away unneeded portions  7  ( FIG. 8 ) of the human femur section  22  to obtain a spinal implant device  6  ( FIG. 13 ) having a notch  36  ( FIG. 10 ) on a top surface  34  ( FIG. 10 ) of the implant device  6  and a notch  37  ( FIG. 10 ) on a bottom surface  35  ( FIG. 10 ) of the implant device. 
     Furthermore, the human femur section  22  can be used to create more than one spinal implant device  6 . In this regard, on one side of the human femur section  22  a first spinal implant device  6  can be cut away from the unneeded portion  7 . Thereafter, a second spinal implant device  6  can be cut out of the unneeded portion  7 , thereby creating two spinal implant devices  6  out of the same femur section  22 . 
     One skilled in the art will readily appreciate that the present disclosure is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the disclosure and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the device as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the device which are obvious to those skilled in the art are intended to be within the scope of the following claims.