Abstract:
The present invention provides a discectomy instrument that is capable of removing portions of the spinal disc between adjacent vertebrae in a controlled manner that is efficient and easy to use. In an exemplary embodiment, the discectomy instrument includes a handle, a rotary scraper, a barrel, a drive shaft, an outer sleeve and a retaining clip.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/154,610, filed on Feb. 23, 2009. The previous application is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an instrument for preparing the space between adjacent vertebrae to stabilize and support the spine. 
     BACKGROUND OF THE INVENTION 
     During spinal surgery, there is a need to remove portions of the spinal disc between adjacent vertebrae. Instruments are inserted into the disc space to remove portions of the disc by piercing the annulus and then the nucleus is mechanically disintegrated with the pieces being removed through suction, forceps, rongeurs, or other similar instruments. 
     There is a need for an instrument that allows for greater motion within the disc space to enable the nucleus to be disintegrated and removed with a minimal amount of time and ease of use for a surgeon. 
     SUMMARY OF THE INVENTION 
     In a preferred embodiment, the present invention provides a discectomy instrument that is capable of removing portions of the spinal disc between adjacent vertebrae in a controlled manner that is efficient and easy to use. The discectomy instrument preferably includes a handle, a rotary scraper, a barrel, a drive shaft, an outer sleeve and a retaining clip. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred or exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a bottom view of one embodiment of a discectomy instrument; 
         FIG. 2  is a side view of the discectomy instrument shown in  FIG. 1 ; 
         FIG. 3  is a side view of a drive shaft of the discectomy instrument shown in  FIG. 1 ; 
         FIG. 4  is a perspective view of the outer sleeve of the discectomy instrument shown in  FIG. 1 ; 
         FIG. 5  is a close-up perspective view of the end of the drive shaft shown in  FIG. 3 ; and 
         FIG. 6  is a close-up perspective view of the end of a rotary scraper of the discectomy instrument shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     With reference to  FIGS. 1 and 2 , a discectomy instrument  10  according to one embodiment of the present invention is illustrated. In a preferred embodiment, the discectomy instrument includes a handle  12 , a rotary scraper  14 , a barrel  16 , a drive shaft  18 , an outer sleeve  20  and a retaining clip  22 . The handle  12  is preferably connected to a medial end of the drive shaft  18  through barrel  16  via an interference fit, snap fit, or similar connection that allows torque applied to handle  12  to transmit to drive shaft  18 . Barrel  16  serves as a connection means and is moveable along a longitudinal axis defined by handle  12  and drive shaft  18 . When moved along the axis in a direction towards the handle  12 , the barrel will disengage the drive shaft  18  from the handle  12 . 
     Located proximate to the barrel  16 , is the outer sleeve  20  which receives the drive shaft  18 . In a preferred embodiment, the outer sleeve  20  has a medial end and a distal end and is connected to the drive shaft  18  via a retainer clip  20  which connects to the drive shaft  18  and outer sleeve  20  in an interference fit. Turning to  FIGS. 1-4 , a retainer clip receiving portion  24  can be seen on the drive shaft  18  and a retainer clip receiving slot  26  can be seen on the outer sleeve  20 . The outer sleeve is connected to the drive shaft  18  in a manner as to allow the drive shaft to rotate with respect to the outer sleeve  20  but not translate with respect to the outer sleeve  20 . In a preferred embodiment, the distal end of the outer sleeve  20  includes an angled edge which is configured and dimensioned to support the rotary scraper  14  in a fixed position as discussed in further detail below. 
     With reference now to  FIGS. 1-3  and  5 , in a preferred embodiment, at a distal end of the drive shaft  18  is a ball joint  28 . The ball joint  28  is coupled to the rotary scraper  14  at one end and to drive shaft  18  at the other end. The ball joint  28  includes a ball member  30 , a first pin which forms the major ball axis and a second smaller pin which is oriented orthogonally to the first pin and extends through the ball member  30  as well as through the first pin. The pins along with the ball member  30  engage the rotary scraper  14 . With additional reference to  FIG. 6 , the rotary scraper  14  includes at least one, but preferably a plurality of blades  32  on one end and a receiving portion  34  on the other end. The receiving portion  34  is configured and dimensioned to engage the first and/or second pins in the ball joint  28  and rest against the ball member  30 . This engagement allows the rotary scraper  14  to pivot with respect to the drive shaft  18  as well as rotate with drive shaft  18 . 
     As mentioned earlier, with the outer sleeve  20  in place surrounding the drive shaft  18 , the distal end of the sleeve  20  engages the receiving end of the rotary scraper  14 . The angled end of the outer sleeve  20  allows for the rotary scraper  14  to rotate but constrains the pivoting movement of the scraper  14  to a predetermined angle. This predetermined angle is a preferred cutting angle that is designed to maximize the cutting efficiency of the rotary cutter  14  during operation of the discectomy instrument  10 . 
     In an exemplary use of the discectomy instrument  10 , after the appropriate intervertebral disc has been identified and the appropriate surgical procedures have been undertaken to create a pathway to the intervertebral disc, the discectomy instrument  10  is introduced into the pathway until the rotary scraper  14  abuts the annulus of the intervertebral disc. The annulus of the disc is then pierced using the instrument  10  or another instrument capable of accomplishing the same task. The rotary scraper  14  of the discectomy instrument  10  is then inserted into the disc nucleus. Following insertion in to the disc nucleus, torque is applied to the handle  12  which in turn transmit the torque to the rotary scraper  14  via the drive shaft  18 . As the rotary scraper  14  rotates, the blades  32  cut away portions of the disc nucleus, which may be removed using forceps, rongeurs, or a suction instrument. The process is continued until the desired portion of the disc nucleus is removed. 
       FIGS. 1-6  illustrate the features of the present device; however, these figures alone do not encompass other possible embodiments. For example, it is contemplated that in one embodiment, the outer sleeve  20  is configured to allow the rotary scraper  14  to articulate in a controlled manner rather than being limited to a fixed angle. In another embodiment, the outer sleeve  20  may be provided with an irrigation and suction channel (not shown) for removing portions of the nucleus while still allowing the rotary scraper  14  to articulate in a controlled manner. Additionally, the rotary scraper  14  can also include a channel (not shown) that is connected to the outer sleeve  20  which allows for the suction and irrigation of the disc space. Yet in another embodiment the rotary scraper  14  can be configured so as to be detachable allowing other tools to be attached to the distal end of the drive shaft  18 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.