Abstract:
A tool for cutting tissue comprising a body, a handle lever, a drive rod, and a cutter beam. The drive rod constructed and arranged for longitudinal movement through the body. The handle lever being operatively engaged to the drive rod, such that when the handle lever is moved between a first position and a second position the drive rod is moved between an advanced position and a retracted position. The drive rod extending from a proximal end of the body to a distal end. The cutter beam being pivotally engaged to the distal end of the body. The cutter beam being pivotally moveable between a non-actuated position and an actuated position. A lower pivot member pivotally connects the distal end of the body and the cutter beam. The cutter beam being further pivotally engaged to a distal end of the drive rod.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an apparatus and method for removing, debriding and/or resecting tissue fragments from a body cavity. In particular, the present invention is directed for use in medical procedures where it may be necessary to remove tissue from a body region. The apparatus and method of the present invention may be especially useful in medical procedures such as orthopedic surgery. 
     2. Description of the Related Art 
     Medical procedures involving the removal of tissue from a bone or other region of a body are well known in the art. Of particular interest to the present invention are procedures relating to removal of diseased or damaged tissue of a spinal disk, such as a discectomy. 
     The spinal disc consists of two types of tissues: the nucleus, and the annulus. The annulus is further divided into the inner and outer annulus. Disc hernias usually consist of a bulge of the nucleus and inner annulus through a rent in a small area of the outer annulus. Partial discectomies are frequently performed when a disc herniation causes pressure on a spinal nerve. The operation consists of removal of the herniated nucleus and portions of the inner annulus. In the past surgeons have used a variety of tools to remove spinal disc tissue during a discectomy. 
     The simplest tools for disc removal are the scalpel and tweezer-type “pick-ups,” which are well known in the art. These tools are very inefficient, as the stringy annular tissues tend to simply move aside and remain attached when these tools are used. Scalpels and pick-ups tend to leave behind fragments of tissue. These fragments can lead to re-herniation—a painful condition that might require a second or even a third operation. 
     So-called “pituitary rongeurs” and “curettes” are the most frequently utilized instruments. Some examples of these instruments may be seen in the following U.S. Patent references: 
     
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 U.S. Pat. No. 
                 Inventor(s): 
               
               
                   
                   
               
             
             
               
                   
                 6,200,320 B1 
                 Michelson 
               
               
                   
                 6,142,997 
                 Michelson 
               
               
                   
                 5,961,531 
                 Weber et al. 
               
               
                   
                 5,766,177 
                 Lucas-Dean et al. 
               
               
                   
                 5,653,713 
                 Michelson 
               
               
                   
                 5,484,441 
                 Koros et al. 
               
               
                   
                 5,451,227 
                 Michaelson 
               
               
                   
                 5,312,407 
                 Carter 
               
               
                   
                 5,026,375 
                 Linovitz et al. 
               
               
                   
                 5,061,269 
                 Muller 
               
               
                   
                 4,990,148 
                 Worrick, III et al. 
               
               
                   
                 4,777,948 
                 Wright 
               
               
                   
                 4,733,663 
                 Farely 
               
               
                   
                 4,722,338 
                 Wright et al. 
               
               
                   
                 3,902,498 
                 Niederer 
               
               
                   
                 3,628,524 
                 Jamshidi 
               
               
                   
                 2,984,241 
                 Carlson 
               
               
                   
                   
               
             
          
         
       
     
     Tools, such as those described in the above cited references, while useful, were not specifically designed to remove disc tissue, and tend to require multiple passes to completely clean out the inner annulus tissue. The use of rongeurs and curettes also tends to leave behind fragments of tissue that may also lead to re-herniation. Furthermore, because these rongeurs and curettes require multiple passes, the operation may be prolonged, possibly leading to increased bleeding and higher infection rates. 
     Many pituitary rongeurs utilize a single cutting blade at the end of a single, unopposed beam. Actuation of the beam, by means of a drive rod, tends to force the distal shaft to move away from the tissue being cut. An open section in the middle of the beam helps reduce this movement, but does not effectively eliminate the unwanted movement. 
     Other methods and devices which have been developed in order to improve the effectiveness of a disc removal operation include electrical and laser based cautery. While electrical cautery does effectively destroy disc tissue, it produces heat and smoke in the process. Heat can injure surrounding tissue, including delicate spinal nerves, potentially causing further harm to the patient. In addition, the production of smoke may obscure vision and interfere with the surgeons ability to properly perform the operation. Laser cautery like electrical cautery methods also produce heat and smoke. Low energy lasers tend to be less effective and therefore the disc removal procedure can be prolonged and less than complete. Higher energy lasers produce more heat and smoke and therefore can lead to tissue damage beyond the area of intended removal. 
     Other devices such as low and high-speed pneumatic or electrical powered rotary burrs are also used. But while they are very useful for removing hard tissues, such as bone, they do not efficiently and effectively remove soft tissues, such as disc material. An example of such a rotary burr is shown in U.S. Pat. No. 5,490,860 to Middle et al., the entire contents of which being incorporated herein by reference. Another type of rotary burr is commercially available and is sold under the name Disc Whisk™ available from Surgical Dynamics Inc. of Norwalk, Conn. Rotary burrs attempt to automate and improve the efficiency of disc removal, but these motorized devices are potentially dangerous when used around the spinal cord and spinal nerves as they develop heat, may grab soft tissue and may penetrate too far. 
     In light of the above it is clear that there remains a need for an improved, hand-powered tool specifically designed for the removal of diseased soft tissue, such as disc tissue. The current invention improves on the current state of the art by providing a apparatus and method which may be used to efficiently, effectively and safely remove soft tissue from a spinal member such as a disk. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a unique reamer tool that may be used to circumferentially resect tissue from a diseased area of a body. The reamer tool of the present invention consists of a sturdy, yet small diameter, hand powered, multi-bladed cutting tool and its method of use. 
     In at least one embodiment of the invention the reamer tool has a cutting beam which is pivotally engaged to the tool assembly, a push rod and handle in a rack and pinion relationship to allow the cutter beam to be pivoted relative to the distal end of the tool assembly. The cutter beam may have a plurality of cutting blades or surfaces. As the cutter beam is pivoted as a result of compression of the handle, the cutting blades cut into and resect the surrounding tissue. 
     In at least one embodiment of the invention the reamer tool may be equipped with a variety of devices designed to make the surgical procedure more efficient. For example the reamer tool may have an attached or integrated suction tube which may be used to remove the tissue which has been resected by the cutting action of the cutter beam. Other devices may also be employed. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     A detailed description of the invention is hereafter described with specific reference being made to the drawings in which: 
     FIG. 1 is a perspective view of an embodiment of the invention; 
     FIG. 2 is a cut-away side view of an embodiment of the invention in the non-actuated position; 
     FIG. 3 is a cut-away side view of the embodiment of the invention shown in FIG. 2 in the actuated position; 
     FIG. 4 is a side view of the distal end of an embodiment of the invention wherein the pivoting action of the cutter beam is illustrated; 
     FIG. 5 is a perspective view of the linkage assembly of the distal end of the reamer tool shown in FIG. 4; 
     FIG. 6 is a top-down view of an embodiment of the cutter beam; 
     FIG. 7 is a cut-away side view of a two handed embodiment of the invention in a non-actuated position; 
     FIG. 8 is cut-away side view of a two handed embodiment of the invention in an actuated, cutting position; 
     FIG. 9 is a side view of a serrated cutting beam; 
     FIG. 10 is an end view of the serrated cutting beam of FIG. 9; 
     FIG. 11 is an enlarged side view of the end of the tool showing the cutting beam attachment; 
     FIG. 12 is an anterior view of a spine showing a way in which the present invention may be used, without a guide tube over the tool; 
     FIG. 13 is a top view of a vertebral body showing one location where the tool can enter and provide reaming; and 
     FIG. 14 is a side view of a spine section showing an alternative manner in which the present invention may be used. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As may be seen in FIG. 1 the reamer tool, indicated generally at  10  may be thought of as being comprised of three main portions: a proximal portion  12 , a middle portion  14 , and a distal portion  16 . 
     As may be seen in FIGS. 2 and 3, the proximal or handle portion  12  consists of a handle body  20 , a handle body lever  22 , a rack  24  and pinion  26 , a pinion handle lever  28 , a shoulder bolt  30 , and a biasing member or return spring  32 . The middle portion  14  consists of a shaft tube  40  through which a drive rod  42  is longitudinally actuated. The drive rod  42  is engaged to the distal end  50  (as may be seen in FIG. 4) of the rack  24 . When a gripping action supplied by a user (not shown) pivotally actuates the pinion handle lever  28  about the pivot member  34 , the teeth  36  of the pinion  26  engage the teeth  38  of the rack  24  resulting in the back an forth movement of the drive rod  42  within the shaft tube  40 . As indicated by arrows  44  and  46  the actuation of the pinion handle lever  28  resulting from a compressive force supplied by a user will move the drive rod  42  distally such as shown in FIG. 3, or proximally when the force is removed, as is shown in FIG.  2 . The position of the pinion handle lever  28  relative to the handle lever  22 , and thus the position of the drive rod  42 , will depend on the extent of the compressive force supplied by a user to the pinion handle lever  28  and handle body lever  22 . 
     In FIG. 2 the reamer  10  is shown in the at rest or non-actuated position. The shoulder bolt  30  is engaged to the proximal end  52  of the rack  24 . The biasing member or return spring  32  is disposed about a bolt shaft  54  which extends proximally from the rack  24  passing through a return member  58 . The bolt shaft  54  ends in an enlarged spring retaining portion  56  of the shoulder bolt  30 . The return spring  32  is biasedly engaged between the spring retaining portion  56  of the shoulder bolt  30  and the return member  58 . This return spring exerts a force sufficient to keep the drive rod  42  extended distally. The force exerted by the return spring  32  is overcome when the pinion handle lever  28  is engaged by the gripping action of the user previously described and shown in FIG.  3 . When the user&#39;s grip is relaxed the force exerted by the return spring  32  against the spring retaining portion  56  and the return member  58  will place the reamer back in the at rest position shown in FIG.  2 . The tool is returned to the rest position so that its profile is small enough to be removed from a guide tube or a hole in bone. 
     The lever may be actuated by an air cylinder, an electric solenoid or any other actuator means. Hand operated levers are shown which are less expensive and easier to clean. 
     In the embodiment shown in FIGS. 1-3, the proximal end  12  contains only one handle body lever  22  and one pinion lever  28 . This embodiment is designed for single-handed operation. However, in at least one alternative embodiment, shown in FIGS. 7 and 8 the reamer tool may be designed for two-handed actuation. As may be seen, a two handed reamer tool  10  has a the proximal end  12  having a handle body lever  22  which is equipped with opposing grip portions  90  and  92 , as well as a pinion lever  28  having opposed section  94  and  96  as well. The present embodiment of the reamer tool  10  may be designed in such a manner that in order to rotate the cutter  60  an two handed grip of alternating action is required to actuate the opposing grips and lever sections  90 ,  94  and  92 ,  96  respectively. 
     Turning to FIG. 4, the distal portion or end  16  of the reamer  10  contains the reamer head or cutting beam  60 . The beam has a plurality of cutting surfaces  61 . In the embodiment shown, the cutting blades are located at the both ends  86  and  88  of the beam. The beam  60  is pivotally connected to a handle body extension  62  by a lower pivot member  64 . 
     The beam  60  is also engaged to the a distal end  66  of the drive rod  42  via linkage assembly  68 . The linkage assembly  68  comprises a pair of beam engagement projections  70 , as best shown in FIG. 5, which are disposed about the linkage tab  72  of the beam  60 , as best shown in FIG.  6 . As may be seen in FIG. 4, a proximal pivot member  74  passes through the linkage tab  72  and the beam engagement projections  70 . As may be seen in FIG. 5, the linkage assembly  68  also includes a pair of rod engagement projections  78 . As shown in FIG. 4, a distal pivot member  76  passes through the pair of rod engagement projections  78  as well as the distal end  66  of the drive rod  42 . As indicated by arrows  80 , the unique arrangement of the beam  60  to the drive rod  42  and extension  62  via the linkage assembly  68  provides the reamer  10  with the ability to rotate the beam  60  about the lower pivot member  64  when the drive rod  42  is distally extended in the manner previously described. When the beam  60  is rotated, the cutting edges  61  will cut into and abrade any tissue which is encountered by the moving cutting edges  61 . 
     As may be seen in FIG. 6, the cutting edges  61  are positioned on both ends  86  and  88  of the beam  60  and may be on opposing sides of the beam  60 , such as may be seen in FIG.  4 . In the present embodiment shown in FIG. 6, the cutting blades  61  may be curved about the shape of a semi-circle, however, the blades  61  may also be provided with other shapes as desired. In addition, the entire perimeter  82  of the beam  60 , or a portion thereof, may include bladed portions  61  which extend beyond the semi-circle shape to form a “U” shape, such that cutting may occur along the lateral edges  63  of the perimeter  82  as well as the semi-circular ends  86  and  88 . As a result, the reamer  10  may be configured to provide a variety of cutting options which will provide a smooth uniform resecting action as the beam  60  rotates back an forth as indicated by arrows  80  in FIG.  4 . 
     In another embodiment of the invention the beam  60  may include one or more backward cutting blades  65 , as is shown in FIG. 4, allowing cutting in both the forward and reverse directions. 
     The reamer  10  of the present invention may be used in a number of different manners as may be recognized by those of skill in the art. When employed to debride an intervertebral disc, it may be understood that the reamer  10  may be used in the following manner. 
     After adequate exposure of a small portion of the disc is accomplished by the surgeon using well known standard techniques, any appropriately sized standard drill may be used to perforate the disc. The drill is guided in a direction that crosses the central portion of the disc, to a depth that comes close to, but does not penetrate the far side of the disc. 
     The distal end  16  of the reamer  10  is then placed into the disc to the full depth of the drilled hole. The reamer  10  is oriented such that its beam  60 , with attached cutting blades  61 , is parallel to the transverse plane of the disc. 
     The application of a manual compression force, such as by gripping the pinion lever  28  toward the handle body lever  22  forces the drive rod  42  in the distal direction. This causes the beam  60  to rotate in an elliptical manner around the lower pivot member  64 . As is shown in FIG. 4, the beam  60  may be pivotally displaced at least 90 degrees when the pinion lever  28  is actuated such as may be seen in FIG.  3 . The cutter will typically provide more than 100 degrees of cutting. This motion causes the cutting blades  61  (and  63 ) to move against any intervening tissue, cleanly cutting that tissue. The return spring  32  forces the drive rod  42  and the beam  60  back to their original and respective non-actuated positions when the pinion lever  28  is relaxed, such as may be seen in FIG.  2 . This procedure may be used to remove the outer nucleus as well as the inner annulus of a spinal disk, leaving the outer annulus intact. Such a procedure is the goal of a partial disectomy. The reamer  10  may then be reoriented 180 degrees, so that the opposite side of the disc can be debrided. 
     In addition, to providing the cutting motion described above, the present invention may also utilize a variety of blade types to provide for different cutting and resecting characteristics. For example, in FIGS. 4 and 6 the cutter beam  60  may be seen to employ one or more straight edge blades on the cutting edges  61 . Alternatively, one or more of the cutting edges  61  may also have serrated teeth  90  such as may be seen in FIGS. 9 and 10. 
     As may best be seen in FIG. 11, when the reamer tool  10  is in the at rest or non-actuated position, the cutter beam  60  is maintained in a position such that the distal end  16  retains a profile substantially less than the distal end would have when in the actuated position such as is shown illustrated in phantom in FIG.  4 . The reduced profile of the non-actuated distal end is sufficiently small to allow insertion of the distal end  16  into a small space or cavity  100  such as is shown in FIG.  12 . 
     In FIGS. 12-13, the reamer tool  10  is seen in use in merely one of a myriad of potential uses. As presently shown, the distal end  16  of the reamer tool  10  may be inserted into an opening or cavity  100  of a spinal body  102 . As the cutter beam  60  is actuated, such as previously described, the cutting surfaces  61  abrade the surrounding tissue  104  to form a transverse cavity  106 . Alternatively, the reamer tool  10  may be used to resect tissue from a spinal body  102  in the middle of a vertebral compression fracture, such as may best be seen in FIG.  14 . 
     After the cavity has been formed, the tool  10  along with any resected tissue is removed. The newly formed cavity may then be filled with filler material such as bone cement and/or graft material. The cavity created by the tool would tend to place the filler in a position where it could accumulate and develop pressure that would tend to elevate or re-expand (or reduce—in orthopedic terms—) the fracture, thereby forcing bone fragments into their pre-injury positions as illustrated in FIG.  14 . 
     In addition to the uses described above, the various embodiments of the reamer tool  10  as described herein may also be used in a wide variety of other procedures. For example, the present reamer tool may be used for removing bone cement from the intramedullary canal of long bones during reconstructive procedures such as joint replacement. The tool may also be useful for debriding cartilage from joints during arthoscopic procedures. Another use may involve using the present reamer tool for certain types of joint arthrodesis, e.g. ankle, inter-tarsal, metatarsal-phalangeal, etc., wherein the tool is used in debriding and preparation of surfaces. 
     Other uses for the present invention may include: using the reamer tool for producing or sculpting channels for tendon insertion and/or reattachment, such as anterior curciate or rotator cuff repairs. The reamer tool may be used in nasal or sinus surgery for sub-mucosal resections. The reamer tool may also find use in certain gynecological procedures such as a dilation and curettage procedure (D&amp;C). Yet another potential use for the present invention would be for fat immobilization during lipo-suction operations. In such a use the tool could be useful in freeing up fatty tissue to improve removal. 
     In addition to being directed to the embodiments described above and claimed below, the present invention is further directed to embodiments having different combinations of the features described above and claimed below. As such, the invention is also directed to other embodiments having any other possible combination of the dependent features claimed below. 
     The above examples and disclosure are intended to be illustrative and not exhaustive. These examples and description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims attached hereto.