Abstract:
An implant that is implanted between adjacent spinous processes for the relief of pain associated with the spine. The device has a spacer to distract apart the adjacent spinous processes. To minimize trauma to the patient, the device has a tapered tissue expander to distract a previously created opening between the adjacent spinous processes. The device also has two wings. The position of one wing is adjustable to allow for ease of assembly in a patent.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation of, and claims priority to, U.S. patent application Ser. No. 10/014,118, filed Oct. 26, 2001, which claims benefit to U.S. Provisional Application No. 60/306,263, filed Jul. 18, 2001, and is a continuation-in-part of U.S. patent application Ser. No. 09/799,215, filed Mar. 5, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/473,173, filed Dec. 28, 1999, now U.S. Pat. No. 6,235,030, which is a continuation of U.S. patent application Ser. No. 09/179,570, filed Oct. 27, 1998, now U.S. Pat. No. 6,048,342, which is a continuation-in-part of U.S. patent application Ser. No. 09/474,037, filed Dec. 28, 1999, now U.S. Pat. No. 6,190,387, which is a continuation of U.S. patent application Ser. No. 09/175,645, filed Oct. 20, 1998, now U.S. Pat. No. 6,068,630, which is a continuation-in-part of U.S. patent application Ser. No. 09/200,266, filed Nov. 25, 1998, now U.S. Pat. No. 6,183,471, which is a continuation of U.S. patent application Ser. No. 09/139,333, filed Aug. 25, 1998, now U.S. Pat. No. 5,876,404, which is a continuation of U.S. patent application Ser. No. 08/958,281, filed Oct. 27, 1997, now U.S. Pat. No. 5,860,977. All of the above applications and patents are incorporated herein by reference in their entireties. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention is directed to an interspinous process implant system and method which can, for example, distract apart and maintain said distraction of adjacent spinous process.  
         BACKGROUND OF THE INVENTION  
         [0003]    As the present society ages, it is anticipated that there will be an increase in adverse spinal conditions which are characteristic of older people. By way of example only, with aging comes increases in spinal stenosis (including, but not limited to, central canal and lateral stenosis), the thickening of the bones which make up the spinal column and facet arthropathy. Spinal stenosis is characterized by a reduction in the available space for the passage of blood vessels and nerves. Pain associated with such stenosis can be relieved by medication and/or surgery. Of course, it is desirable to eliminate the need for major surgery for all individuals and in particular for the elderly.  
           [0004]    Accordingly, there needs to be developed procedures and implants for alleviating these and other spinal conditions, which procedures and implants are minimally invasive, can be tolerated by the elderly and can be performed preferably on an outpatient basis.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention is directed to providing a minimally invasive apparatus and method for alleviating discomfort associated with the spinal column.  
           [0006]    The present invention provides for apparatus and method for relieving pain by relieving the pressure and restrictions on the aforementioned blood vessels and nerves. Such alleviation of pressure is accomplished in the present invention through the use of an implant and method which distract the spinous process of adjacent vertebra in order to alleviate the problems caused by spinal stenosis and facet arthropathy and the like as well as other spinal ailments. While the implant and method particularly address the needs of the elderly, the invention can be used with individuals of all ages and sizes where distraction of the spinous process would be beneficial.  
           [0007]    In one aspect of the invention, an implant is provided for relieving pain comprising a device positioned between a first spinous process and a second spinous process. The device includes a spinal column extension stop and a spinal column flexion non-inhibitor.  
           [0008]    In a further aspect of the invention, the implant includes a first unit having a body with a guide or tissue expander and a first wing, with the first wing located at first end of the body. The guide extends from a second end of the body located distally from the first wing. The implant further includes a sleeve or spacer provided over said body. The implant further includes a second wing and a device for securing the second wing to the first unit, wherein the sleeve or spacer is located between the first and second wings.  
           [0009]    In yet still a further aspect of the invention, the implant includes a sleeve which is rotatable relative to the wings of the implant in order to be able to accommodate the anatomical structure of spinous processes.  
           [0010]    In still another aspect of the invention, the implant includes a second wing that is movable toward the first wing after the second wing is assembled to the first unit in the patient. In this aspect a fastener can be operated to cause the second wing to move toward the first wing. Accordingly, the implant can be easily assembled in the patient without concern for the shape of the spinous processes and then the first and second wings can be drawn together so that these wings are positioned closer to the spinous processes.  
           [0011]    In another aspect the second wing includes an alignment tab which is received in an alignment groove of the first unit in order to guide the second wing as it is urged toward the first wing.  
           [0012]    In another aspect of the invention a ramp mechanism is used to urge the second wing toward the first wing.  
           [0013]    Other implants and methods within the spirit and scope of the invention can be used to release pain associated with the spine and/or increase the volume of the spinal canal thereby alleviating restrictions on vessels and nerves associated therewith and associated pain. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of an embodiment of the present invention;  
         [0015]    [0015]FIG. 2 is a top view of an embodiment of the adjustable wing of the present invention;  
         [0016]    [0016]FIG. 3 is a perspective view of an embodiment of the fastener used in the present invention;  
         [0017]    [0017]FIG. 4 is cut-away view illustrating the interaction between the fastener and the adjustable wing with the adjustable wing is in a first position;  
         [0018]    [0018]FIG. 5 is a cut-away view illustrating the fastener engaging the adjustable wing with the adjustable wing in a second position;  
         [0019]    [0019]FIG. 6 is a side view illustrating an embodiment of the present invention as implanted between adjacent spinous processes; and  
         [0020]    [0020]FIG. 7 is a front view of an embodiment of the present invention as implanted between adjacent spinous processes. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Referring to FIG. 1, the implant device  100  has a main body  101 . The main body  101  includes a spacer  102 , a first wing  104 , a tapered front end, lead-in guide or tissue expander  120  and an alignment track  106 . The main body  101  is inserted between adjacent spinous processes. Preferably, the main body  101  remains safely and permanently in place without attachment to the bone or ligaments. All of the components of the implant device  100  are made of biologically acceptable material such as, but are not limited to, high strength titanium alloy or stainless steel. Preferably the first wing  104  is laser welded to the main body  101 .  
         [0022]    The tip of the tissue expander  120  has the smallest diameter, allowing the tip to be inserted into a small initial dilated opening. The diameter and/or cross-sectional areas of the tissue expander  120  then gradually increases until it is substantially similar to the diameter of the main body  101  and spacer  102 . The tapered front end  120  makes it easier for a physician to urge the implant device  100  between adjacent spinous processes. When urging the main body  101  between adjacent spinous processes, the front end  120  distracts the adjacent spinous processes to the diameter of the spacer  102 . As shown in FIG. 1, the tissue expander  120  is a pyramid shape. In another embodiment the tissue expander preferably has an angle of twenty-five degrees that allows it to clear the facet. This reduces the length of the front end  120 . One will appreciate that the shape of the tissue expander  120  can be other shapes such as, but not limited to, cone shaped, or any other shape with a small lead-in cross-section expanding into a larger cross-section. These types of shapes gradually distract the spinous processes to a sufficient distance so that the spacer  102  can conveniently fit between the spinous processes.  
         [0023]    The spacer  102  can be made of stainless steel, titanium, a super-elastic material or silicone or other biologically acceptable material. The material can be rigid or resilient as desired. As shown in FIG. 1, the spacer  102  is an elliptically shaped cylinder. One will appreciate that the spacer can consist of other shapes such as, but not limited to, egg-shaped, round-shaped or saddle-shaped. For example, the spacer  102  can be saddle-shaped along the surface which engages the spinous processes so that the high edges and the lower central portions can more fully accommodate the shape of the spinous processes. Preferably, the spacer  102  can swivel, allowing the spacer  102  to self-align relative to the uneven surface of the spinous process. This ensures that compressive loads are distributed equally on the surface of the bone. By way of example only, the spacer  102  can have diameters of six millimeters, eight millimeters, ten millimeters, twelve millimeters and fourteen millimeters. These diameters refer to the height by which the spacer distracts and maintains apart the spinous process. Thus for an elliptical spacer the above selected height would represent the small diameter measurement from the center of the ellipse. The largest diameter would be transverse to the alignment, of the spinous process, one above the other. Smaller and larger diameters are within the scope of the invention.  
         [0024]    The shape of the spacer  102  and for that matter the shape of the entire implant is such that for purposes of insertion between the spinous processes, the spinous processes do not need to be altered or cut away in any manner in order to accommodate the implant  100 . Additionally, the associated ligaments do not need to be cut away and there would be very little or no damage to the other adjacent or surrounding tissues other than piercing through and separating, or dilating an opening in a ligament.  
         [0025]    The first wing  104  has a lower portion  116  and an upper portion  118 . The upper portion  118  is designed to preferably accommodate, in this particular embodiment, the anatomical form or contour of the L4 (for an L4-L5 placement) or L5 (for an L5-S1 placement) vertebra. It is to be understood that the same shape or variations of this shape can be used to accommodate other vertebra. The lower portion  116  is also rounded to accommodate, in a preferred embodiment, the vertebra. The lower portion  116  and upper portion  118  of the first wing  104  will act as a stop mechanism when the implant device  100  is inserted between adjacent spinous processes. The implant device  100  cannot be inserted beyond the surfaces of the first wing  104 . Additionally, once the implant device  100  is inserted, the first wing  104  can prevent side-to-side, or posterior to anterior movement of the implant device  100 .  
         [0026]    The implant device  100  also has an adjustable wing  110 . The adjustable wing  110  has a lower portion  108  and an upper portion  114 . Similar to the first wing  104 , the adjustable wing  110  is designed to accommodate the anatomical form or contour of the vertebra.  
         [0027]    The adjustable wing  110  is secured to the main body  101  with a fastener  122  provided through tapered cavity  130 . The adjustable wing  110  also has an alignment tab  112 . When the adjustable wing  110  is initially placed on the main body  101 , the alignment tab  112  engages the alignment track  106 . The alignment tab  112  slides within the alignment track  106  and helps to maintain the adjustable wing  110  substantially parallel with the first wing  104  in this preferred embodiment. When the main body  101  is inserted into the patient and the adjustable wing  110  has been attached, the adjustable wing  110  also can prevent side-to-side, or posterior to anterior movement.  
         [0028]    Referring now to FIG. 2, the adjustable wing  110  includes the above mentioned tapered cavity  130 . The tapered cavity  130  has a middle portion  132 , two end portions  134  and a tapered wall  131 . The diameter of the middle portion  132  is larger than the diameter of either end portion  134 . The tapered wall  131  has a larger diameter at the top surface of the adjustable wing  110  than at the bottom surface. Accordingly a cone-like shape is formed. When the fastener  122  engages the main body  101  and is rotated, the fastener  122  travels into the main body  101  (see FIG. 1). As the fastener  122  travels into the main body  101 , the adjustable wing  110  will travel along the alignment track  106  towards the first wing  104 . The alignment tab  112  engages the alignment track  106  and functions as a guide, keeping the adjustable wing  110  and the first wing  104  substantially parallel to each other.  
         [0029]    The fastener  122  has a tapered head  123 , a middle section  136  and threaded bottom section  138  (see FIG. 3). The top end of the tapered head  123  was a diameter substantially similar to the diameter of the top surface of the tapered cavity  130 . The diameter of the tapered head  123  is reduced as the tapered head meets the middle section  136 . The slope of the tapered head  123  is similar to the slope of the tapered cavity  130  of the adjustable wing  110 . The middle section  136  has a diameter substantially similar to the end portions  134  of the adjustable wing  110 . The threaded bottom section  138  has a slightly larger diameter than the middle section  136  and is in one embodiment slightly smaller than the diameter of the middle portion  132  of the adjustable wing  110 .  
         [0030]    As the diameter of the end portions  134  are smaller than the diameter of the bottom section  138 , the fastener  122  cannot initially be placed through the end portions  134  of the adjustable wing  110 . Accordingly, to fasten the adjustable wing  110  to the main body  101 , the threaded bottom section  138  of the fastener  122  is placed through the middle portion  132  of the adjustable wing  110  and into the main body  101 . With a turn of the fastener  122 , the threaded portion of the bottom section  138  will engage the main body  101 .  
         [0031]    In another preferred embodiment the diameter of threaded bottom section  138  is larger than the diameter of the middle portion of the adjustable wing  110 . For this embodiment, the fasteners  122  is inserted into the cavity  130  by slicing the cavity  130  (FIG. 2) through the thinnest portion of the wall, spreading the wall open, inserting the middle section  136  in the cavity with the threaded bottom section  138  projection below the cavity  130 , and laser welding the wall closed. The slicing step preferably includes using a carbide slicing device.  
         [0032]    When the adjustable wing  110  is in the position furthest from the position of the first wing  104 , the tapered head  123  of the fastener  122  is substantially out of, and not engaging, the tapered cavity  130  of the adjustable wing  110  (See FIG. 4). As the fastener  122  is rotated, the fastener  122  will continue to engage, and travel further into, the main body  101 . As the fastener  122  travels downwardly into the main body  101 , the tapered head  123  of the fastener  122  contacts the wall  131  of the tapered cavity  130 . The adjustable wing  110  can freely slide back and forth, limited by the end portions  134  of the tapered cavity  130 . When the tapered head  123  contacts the wall  131  of the tapered cavity  130 , the adjustable wing  110  moves towards the first wing  104  guided by the alignment tab  112  in the alignment track  106 . Therefore, the adjustable wing  110  remains substantially parallel to the first wing  104  in this preferred embodiment as the adjustable wing  110  moves toward the first wing  104  (see FIG. 5). It is to be understood that the tab  112  and the track  106  can be eliminated in another embodiment of the invention.  
         [0033]    As shown in FIG. 5, the tapered head of  123  of the fastener  122  is mated in the tapered wall  131  of the adjustable wing  110 . Accordingly, with this ramp mechanism, the adjustable wing  110  is urged toward the spinous processes and the first wing  104  and is locked in position at its closest approach to the first wing  104 . This arrangement allows the surgeon to loosely assemble the implant in the patient and then urge the adjustable wing closer to the first wing, by rotating fastener  122  into body  110  making the implanting method more tolerant to the anatomy of the patient.  
         [0034]    The structure of the spine is of course unique for every patient. Accordingly if the width of the spinous processes is excessive, the adjustable wing can be left in a position that is between that shown in FIG. 4 and that shown in FIG. 5. The separation between the first wing  104  and the adjustable wing  110  can be incrementally adjusted by the number of turns of the fastener  122 .  
         [0035]    [0035]FIGS. 6 and 7 illustrate the position of the implant device  100  in a patient. As shown by FIG. 6, the lower portion  116  and upper portion  118  of the first wing  104  function to prevent side-to-side movement, toward and away from the vertebral body ensuring that the implant device  100  remains in place. Similarly, the adjustable wing  110  will also prevent excessive side-to-side movement. The wing also prevents motion in the direction of the main body into the space between the spinous processes.  
         [0036]    The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to the practitioner skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalence.