Abstract:
A method of repairing an annulus of an intervertebral disc includes excising, with a cutting tool, a damaged area of the annulus, thereby creating a space in the annulus, the space being defined by first and second annulus ends; making a partial incision at the first annulus end generally adjacent to the excised area, creating a flap of annulus; stretching the flap across the space, and attaching the flap to the second annulus end.

Description:
[0001]     This application claims the benefit of the earlier filing date of U.S. Provisional Application No. 60/705,147, filed on Aug. 4, 2005, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND  
       [0002]     1. Technical Field  
         [0003]     This invention relates generally to orthopedic spine surgery and in particular to devices, systems and methods for use in the repair of the annulus of the intervertebral disc.  
         [0004]     2. Background Art  
         [0005]     The use of discectomy procedures for the repair of herniated intervertebral discs in the human spinal column is well documented in the literature and techniques for performing these procedures using a variety of methods have been well described in the prior art. In these procedures the disc is excised, the herniation removed along with a portion of the nucleus pulposus and the patient&#39;s symptoms typically abate. The application of these procedures has become widely accepted throughout the medical community and they have proven to be highly successful clinically.  
         [0006]     Many techniques have been described and are currently used to access and then incise disc herniations, and even more methods, and numerous devices, are available for the removal of the herniation and subsequent nuclear material from the disc space, including the use of mechanical devices such as curettes and rongeurs, ultrasonic devices, mechanical shavers and heat generating equipment. Whenever such methods and devices are used the remaining void in the annular wall remains unfilled. Few materials or devices have been developed which can be reliably utilized to close this void. Consequently, to prevent the later escape of nuclear material from the remaining hole, surgeons have taken to removing more of the disc material than is necessary so that no material remains near the opening. This appears to address the clinical need, but the effect on the residual disc is unclear and is suspected to be negative, possibly weakening the remaining structure and increasing the potential for later expulsion of the nucleus that remains.  
         [0007]     More recently there has been considerable focus on this problem of closing the void and a number of devices have been developed to try and address this clinical need. This includes some configurations that thread into the opening or try to attach to the bone around the void, but this is difficult due to the dynamic nature of the interface, whereby the vertebrae move independently of each other making it difficult to establish a rigid bridge across the opening or void.  
         [0008]     There is, therefore, a demonstrated need for an improved method and surgical technique for excising, then repairing these disc herniations in a simple manner that can seal the annulus and prevent the later expulsion of nucleus pulposus and subsequent recurrence of the herniation. The prior art methods and devices have not been capable of providing these features.  
       SUMMARY OF THE DISCLOSURE  
       [0009]     It is a general object of the present invention to provide a method for spine surgery to repair and seal a disc annulus.  
         [0010]     It is a further object of the present invention to provide a method for spine surgery to repair and seal a disc annulus due to a herniation or other damage.  
         [0011]     It is a further object of this invention to provide a minimally invasive method whereby a cannula or tool is used for performing spine surgery to repair and seal a disc annulus.  
         [0012]     It is a further object of this invention to provide a device for performing minimally invasive spine surgery to repair and seal a disc annulus.  
         [0013]     It is a further object of this invention to provide a method for performing spine surgery to repair and seal a disc annulus using a portion of the patient&#39;s injured disc which is still partially attached.  
         [0014]     It is a further object of this invention to provide a method for performing spine surgery to repair and seal a disc annulus using an autograft of the patient&#39;s annulus.  
         [0015]     In accordance with the principles of the present invention, these objectives are achieved by providing a method of repairing an annulus of an intervertebral disc. The method includes excising, with a cutting tool, a damaged area of the annulus, thereby creating a space in the annulus, the space being defined by first and second annulus ends; making a partial incision at the first annulus end generally adjacent to the excised area, creating a flap of annulus; stretching the flap across the space; and attaching the flap to the second annulus end.  
         [0016]     In accordance with another aspect of the invention, a method of repairing an annulus of an intervertebral disc includes excising, with a cutting tool, a damaged area of the annulus, thereby creating a space in the annulus, the space being defined by first and second annulus ends; and attaching a connector between the first and second ends so that the connector spans the space.  
         [0017]     In accordance with yet another aspect of the invention, a tool is provided for cutting and removing a portion of an annulus of an intervertebral disc. The tool includes an elongated body having a bore there-through. A cutting structure is associated with the elongated body and is constructed and arranged to cut a portion of the annulus. A structure is movable within the bore and has an end that is constructed and arranged to engage and thereby remove the portion cut by the cutting structure.  
         [0018]     Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     The foregoing and other features of the disclosed embodiments will become apparent to one skilled in the art, relates upon consideration of the following description, with reference to the accompanying drawings, wherein:  
         [0020]      FIG. 1  is a transverse sectional view through a diseased vertebral disc showing a conventional herniation at the posterior edge.  
         [0021]      FIG. 2  is a transverse sectional view through the diseased vertebral disc of  FIG. 1  showing a cannula or a cutting tool of the present invention used to excise the bulge.  
         [0022]      FIG. 3  is a transverse sectional view through the diseased vertebral disc of  FIG. 2  showing a resected portion of an annular wall and a partial surgical cut.  
         [0023]      FIG. 3A  is an enlarged view of the portion encircled at A in  FIG. 3  showing the herniated area and the surgical cut made adjacent to the resected annulus.  
         [0024]      FIG. 4  is a transverse sectional view through the diseased vertebral disc of  FIG. 3  showing an annular flap folded over to close a gap.  
         [0025]      FIG. 4A  is an enlarged view of the portion encircled at A in  FIG. 4  showing the herniated area and the annular flap pulled across the gap and stitched.  
         [0026]      FIG. 5  is a front view of a cutting tool provided in accordance with the principles of the present invention, shown with a collar in a first position.  
         [0027]      FIG. 6  is a front view of a cutting tool provided in accordance with the principles of the present invention, shown with the collar in a second, blade-extending position and a barb structure for excising an annulus portion.  
         [0028]      FIG. 7  is a front view of a cutting tool provided in accordance with another embodiment of the present invention.  
         [0029]      FIG. 8  is a top view of the cutting tool of  FIG. 7 .  
         [0030]      FIG. 9  is an enlarged view of a connector, in accordance with the principles of the invention, spanning a space defined by removal of a damaged area of an annulus.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0031]     With reference to FIGS.,  1 - 4 , a method repairing the intervertebral disc annulus damaged as a result of a herniation or damage to the disc will be described in accordance with the principles of the present invention.  FIGS. 1-4  illustrate a transverse sectional view of the vertebral body, generally indicated at  1 , and the disc  5 . Common to  FIGS. 1-4  is the relevant anatomy of the transverse sectional view including the transverse process  2 , lamina  3 , pedicle  4 , annulus fibrosus  6  of the disc, and nucleus pulposus  7  of the disc.  FIG. 1  shows the vertebral body  1 , whereby the disc  5  is herniated  8 .  FIG. 2  illustrates a minimally invasive cannula  13 , positioned over the herniation  8  and passing by the lamina  3 . A cutting tool (not shown in  FIG. 2 ) can be passed through the cannula  13 , to excise the disc annulus  6 . Also in  FIG. 2 , using the minimally invasive cannula  13 , subsequent instruments can be passed there-through to remove a portion of the disc nucleus  7 .  
         [0032]      FIG. 3  illustrates a gap or space  9  in the disc annulus  6  created by the surgeon.  FIG. 3  also shows a surgical incision  10  made in the disc annulus  6 , adjacent to the space  9 , such that the distance from the edge of the space  9  to the surgical incision  10  creates a portion of disc tissue or “flap”  11  that can be stretched across the space  9 . Further, the surgical incision  10  is not cut so deep as to invade the disc nucleus  7 .  FIG. 4  illustrates the flap  11  of the disc annulus  6  being stretched across the space  9  and securely attached  12  to the other side of the disc annulus  6 .  FIG. 4  also shows where the flap  11 , is attached (the attachment indicated at  12 ) to its adjacent annulus  6  to close the disc space  9  and prevent any further herniation of the disc nucleus  7 .  
         [0033]      FIGS. 3A and 4A  show enlarged views of the portions encircled at A in  FIGS. 3 and 4 , respectively, for clarification.  FIG. 3A  shows the surgical cut  10  to create the flap  11  in the disc annulus  6  at an annulus first end that defines the space  9 .  FIG. 4A  shows the flap  11  being stretched across the space  9  and securely attached at a second annulus end  14  that defines the space  9  using sutures or a “stitch”  12 .  
         [0034]     In the preferred embodiments, the components, namely the instruments and devices or products used to attach the annular flap, are preferably manufactured from implant grade metallic materials such as, but not limited to, titanium and cobalt chromium alloys, nickel titanium alloys, and stainless steels. The components can also be produced from thermoplastics, composites of plastic and metal, or bioabsorbable materials. The instruments to perform the procedure may include a series of cannulae and dilators, various punches or cutters to create the flap and tools for stretching and holding the flap as explained more fully below. The manufacturing of the implants and instruments utilize standard processes but may also benefit from nano-manufacturing methods, as they develop.  
         [0035]     It can be appreciated that the cuts made in the annulus may be made in other geometrical configurations than shown herein. The sutures or attachment devices  12  may be manufactured from polymeric implantable materials, such as polyetheretherketone (PEEK) or polyaryletherketone (PAEK) or composites thereof incorporating carbon fibers or similar materials. The instruments may be offered as a system, or kit, presented to the operating room in a case that contains various sizes and designs of components.  
         [0036]     The sutures may be manufactured from bioabsorbable materials, including, but not limited to, polylactic acids (PLLA), polyglycolic acids (PGA), Polyglecaprone 25, Polyglactin-91 or non-absorbable materials such as, nylon and polypropylene. Synthetic or natural suture material, such as catgut, may also be employed. The sutures may be offered in sterile-packaged configuration to the operating room. The attachment of the annular flap may be accomplished by various mechanical assembly means, including but not limited to, stapling, sewing, hooks, and adhesives. The system components may be configured for application to other tissues and areas of the body.  
         [0037]     With reference to  FIG. 9 , instead of using the flap  11  stretched across the space  9 , a connector  15  (mechanical or natural) can be connected between the two ends  13  and  14  defining the space  9  so as to span the space  9 . The attachment  17  of the connector  15  to the annulus  6  can be, for example, bio-compatible adhesive, sutures, staples, spearing, staking, male and female mating parts, fasteners, etc.  
         [0038]     As noted above, a cutting tool is employed to create the surgical cut  10 . With reference to  FIGS. 5 and 6 , a cutting tool is shown, generally indicated at  20 , in accordance with the principles of the present invention. The cutting tool  20  includes an elongated, generally cylindrical main body  22  that includes a bore  24  there-through, the function of which will be explained below. A collar  26  is provided about at least a portion of the body  22 . The collar  26  is movable along axis A of the body  22  such as, for example, via threaded engagement  23  of the collar  26  with a periphery of the body  22 .  
         [0039]     The collar  26  includes an annular groove  28  in the periphery thereof. Linkage structure, preferably in the form of a pair of links  30 , is provided to couple the collar  26  to cutting structure, preferably in the form of cutting blades  32 . Each blade  32  is also coupled to the body  22  via a hinge connection  33 . One end of each link  30  is received in the groove  28  to define a first hinge/slop joint  34  and the other end of each link  30  is coupled with an associated blade  32  via a second hinge/slop joint  36 . Thus, the hinge/slop joints  34 ,  36  allow for annular motion (rotation) of the collar  26 . With reference to  FIG. 6 , as the collar  26  is moved along axis A towards the end  38  of the body  22  by rotating it in one direction with respect to the body  22  (via the threaded engagement), the cutting diameter D (distance between blades  32 ) of the blades  32  increases. Rotation of the collar  26  in an opposite direction decreases the cutting diameter D.  
         [0040]     The cutting tool  20  can be used with or in place of the cannula  13  in the above-described method. Thus, to remove the herniation  8  of  FIG. 2 , a barb  40  ( FIG. 6 ) is inserted into the herniation  8 . The cutting tool  20  is then placed over an end of the barb  40  so that a portion of the barb  40  is within the bore  24 . The collar  26  is adjusted (e.g., rotated) to set the cutting blades  32  to the appropriate cutting diameter D. The collar  26  can be coupled to a handle (not shown) that is accessible by the surgeon for rotating the collar  26 . The cutting tool  20  is then rotated to make a circular cut about the herniation  8 . The barb  40  and the cutting tool  20  are pulled upwardly with the barb  40  removing the herniation  8 . It can be appreciated that other structure can be used instead of the barb  40  to remove the herniation  8 .  
         [0041]     With reference to  FIGS. 6 and 7 , another embodiment of a cutting tool  20 ′ is shown. Instead of providing adjustable cutting blades as in the tool  20  of  FIGS. 5 and 6 , the tool  20 ′ has at least one cutting structure or blade  32 ′ of a fixed diameter D. In the embodiment, a pair of blades  32 ′ is provided in spaced relation such that when the tool  20 ′ is rotated, a cut of a certain diameter can be made. Alternatively, a circular blade of a certain diameter can be provided and can be rotated to make a cut, or can be used as a punch. The tool  20 ′ has an elongated body  42  with a bore  44  there-through for receiving the barb  40  (see  FIG. 6 ) so that the damaged area (e.g., herniation) can be removed.  
         [0042]     A plurality of tools  20 ′ is preferably available to the surgeon in a kit so that the surgeon can choose the appropriate diameter blade  32 ′. For example, six or seven tools  20 ′ can be provided that increase in blade diameter in 1 mm increments.  
         [0043]     Another embodiment of the tool (not shown) includes replacing the blades  32 ′ shown in  FIG. 7  with a laser to facilitate the cutting.  
         [0044]     Although the embodiments have been described in a manner that the damaged area of the disc annulus is a herniation, the damaged area can be, but is not limited to, a radial tear, a tumor, and a rim lesion.  
         [0045]     The elongated body  22  of tool  20  and the elongated body  42  of tool  20 ′ can each also include additional lumens (one shown at  46 ) that can be used for lavage (irrigation), aspiration (suction), fiber optics for illumination, and/or visualization of the surgical site.  
         [0046]     Thus, the method and tool described herein provides an effective way to remove and repair an annulus of an intervertebral disc.  
         [0047]     The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.