Abstract:
A method of treating a compression fracture in a bone comprising the steps of forming a transverse cavity within said bone defined by at least one substantially flat surface lying substantially in a transverse plane formed by and communicating with said transverse cavity, the transverse cavity having a substantially uniform transverse extent and a maximum height, the maximum height being less than said transverse extent and applying a force within said transverse cavity generally normal to said surface to displace said surface and restore said bone to its substantially normal anatomic position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of Ser. No. 11/282,910 filed on Nov. 18, 2005 which is a divisional application of U.S. patent Ser. No. 10/440,036, filed May 16, 2003, which claims priority to U.S. patent application Ser. No. 09/909,667, filed Jul. 20, 2001, which claims priority to U.S. Provisional Application No. 60/219,853 filed Jul. 21, 2000, the entirety of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to methods and devices for correcting bone abnormalities and involves the use of a surgical mesh bag which is inserted into a prepared cavity in bone. The bag is inflated using bone replacement material to expand and fill the cavity.  
         [0003]     U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich, describe a device and method for stabilizing the spinal segment with an expandable, porous fabric implant for insertion into the interior of a reamed out disc which is packed with material to facilitate bony fusion. In the present invention, a similar bag is used to correct bone abnormalities including, but not limited to, bone tumors and cysts, tibial plateau fractures, avascular necrosis of the femoral head and compression fractures of the spine.  
         [0004]     U.S. Pat. Nos. 5,108,404 and 4,969,888 to Scholten et al., describe a system for fixing osteoporotic bone using an inflatable balloon which compacts the bone to form a cavity into which bone cement is injected after the balloon is withdrawn. The invention requires the use of fluoroscopy to monitor the injection and to help guard against cement leakage through fissures in bone. Unfortunately, such leakage is known to occur in spite of these precautions. Since such leakage may cause serious injury, including paralysis, an improved device and method is needed.  
         [0005]     U.S. Pat. No. 5,972,015 to Scribner et al., describes a system of deploying a catheter tube into the interior of a vertebra and expanding a specially configured nonporous balloon therewithin to compact cancellous bone to form a cavity. The Scribner patent approach utilizes a non-porous balloon which is inflated within the bone to cause compression. The cavity thus formed, may then be filled with bone cement. Unfortunately, the bag used by Scribner may be ruptured during expansion to compact cancellous bone due to sharp projections found within the cavity to be expanded. Filling the cavity eventually formed could allow leakage of bone cement out of the bone against vessels or nerves which may cause undesirable complications.  
         [0006]     The present invention involves an improvement of all of the previous techniques and avoids complications that could occur with the system of U.S. Pat. No. 5,972,015.  
         [0007]     All U.S. patents, applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.  
         [0008]     The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. § 1.56(a) exists.  
       SUMMARY OF THE INVENTION  
       [0009]     The invention provides a method of correcting numerous bone abnormalities including bone tumors and cysts, avascular necrosis of the femoral head, tibial plateau fractures and compression fractures of the spine. The abnormality may be corrected by first accessing and boring into the damaged tissue or bone and reaming out the damaged and/or diseased area using any of the presently accepted procedures, or the damaged area may be prepared by expanding a bag within the damaged bone to compact cancellous bone. After removal and/or compaction of the damaged tissue the bone must be stabilized.  
         [0010]     In cases in which the bone is to be compacted, the methods and devices of this invention employ a catheter tube attached to an inflatable porous fabric bag as described in U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich, the disclosures of which are incorporated herein by reference. Those bags may be inflated with less fear of puncture and leakage of the inflation medium than thin walled rubber balloons. They may also be used over a Scribner balloon to protect the balloon from breakage and eventually seepage.  
         [0011]     The devices of U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich, additionally provide the surgeon with the advantage of safely skipping the first balloon inflation steps of Scribner and Scholten, by expanding the bag through introduction of fill material, such as a bone repair medium thereby correcting the bony defect and deformity and stabilizing it in one step of the procedure.  
         [0012]     As indicated above, the damaged bone may be removed by any conventional reamer. Examples of reamers are described in U.S. Pat. No. 5,015,255; U.S. patent application Ser. No. 09/782,176, to Kuslich et al., entitled “Expandable Reamer” and filed Feb. 13, 2001; and U.S. patent application Ser. No. 09/827,202 to Peterson et al., entitled “Circumferential Resecting Reamer Tool,” filed Apr. 5, 2001, the disclosure of which has been expressly recited herein at the end of this application. Other examples of reamers are known and may be used. After the damaged bone or tissue has been removed, bone repair medium may then be inserted into the cavity thus formed, via a catheter and expandable fabric bag as described in U.S. Pat. Nos. 5,549,679 and 5,571,189.  
         [0013]     Alternatively, either a smaller than desired cavity may be formed into the bone to be enlarged by compaction or the cavity may be formed only by compaction through introduction of fill material into the bag. In either case, the bag may be positioned over the inflation balloon which is then inflated within the bone site to provide the degree of compaction required. The bag may then be filled with fill material, such as bone repair medium while the balloon remains in place within the bag. Alternatively, the balloon may be removed from the bag prior to filing the bag. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:  
         [0015]      FIG. 1  is a side elevational view of a vertebra that is fractured and in need of repair;  
         [0016]      FIG. 2  is a side view of the vertebra of  FIG. 1  being reamed out with a reaming tool from the anterior approach;  
         [0017]      FIG. 3  is a top view of the vertebra of  FIG. 1  showing the reamer forming a pair of cavities within the vertebra from the anterior approach;  
         [0018]      FIG. 4  is a side elevational view of the vertebra of  FIG. 2  showing placement of an expandable fabric bag of the invention;  
         [0019]      FIG. 5  is a top elevational view of the vertebra of  FIG. 3  showing a second of two expandable fabric bags of the invention being positioned;  
         [0020]      FIG. 6  is a side view of a vertebra being reamed from a posterior approach;  
         [0021]      FIG. 7  is a top view of the vertebra of  FIG. 6  with a bag in place and a second cavity being reamed;  
         [0022]      FIG. 8  is a side elevational view of the vertebra of  FIG. 6  with an expandable fabric bag of the invention in place;  
         [0023]      FIG. 9  is a top view of the vertebra of  FIG. 7  with one bag inflated and the second bag being deployed;  
         [0024]      FIG. 10  is a side elevational view showing the vertebra cavity being expanded with an expandable fabric bag about an inflation device in cross-section;  
         [0025]      FIG. 11  shows the bag system of  FIG. 10  with the vertebra in phantom to show the bag system;  
         [0026]      FIG. 12  is a view similar to  FIG. 10  showing a different approach to the interior of the vertebra;  
         [0027]      FIG. 13  is a view similar to  FIG. 11  showing the approach of  FIG. 12 ;  
         [0028]      FIG. 14  shows the bag of  FIG. 12  in a closed, filled and expanded position;  
         [0029]      FIG. 15  is a top view of the bag system of  FIG. 12  being inflated through a catheter tube;  
         [0030]      FIG. 16  shows a femoral head with avascular necrosis;  
         [0031]      FIG. 17  shows the femoral head of  FIG. 16  being reamed out;  
         [0032]      FIG. 18  shows placement of a bag system of the invention within the cavity in the femoral head;  
         [0033]      FIG. 19  is a side elevational view of a tibial plateau fracture;  
         [0034]      FIG. 20  is a side view of the fracture of  FIG. 19  with a cavity being formed with a reamer; and  
         [0035]      FIG. 21  shows the tibial plateau fracture repaired with an expanded inflatable fabric bag in place. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]     In the following detailed description, similar reference numerals are used to depict like elements in the various figures.  
         [0037]      FIG. 1  shows a typical vertebra  10  having compression fractures  12  that is in need of repair. As indicated above the damaged portion of the vertebra  10  may be reamed out, compacted, or otherwise repaired. For example,  FIG. 2  shows a reamer  14  entering the vertebra  10  anteriorly to make an opening  15  and cavity  16 . Alternatively, multiple cavities  16  may be formed such as is shown in  FIG. 3 .  
         [0038]     As previously mentioned, the damaged portion of the vertebra  10  may be compacted in addition to or instead of being reamed out. In  FIG. 4 , a delivery tube or catheter  20  is seen in the process of delivering an expandable fabric bag  22  into the vertebra  10  or into a cavity  16  present therein. As indicated, the cavity  16  may have been created through reaming, compaction by the bag  22  or other device, or by other means. Once the bag  22  is positioned within the vertebra  10 , the bag  22  may be inflated or expanded to the limits of the cavity  16  thus formed through insertion or injection of fill material  19  into the interior  21  of the bag  22 .  
         [0039]      FIG. 5  shows a single filled expandable fabric bag  22  in place with a second expandable bag which is being inserted and expanded within the cavity  16 .  
         [0040]      FIGS. 6-9  illustrate a procedure in which the opening  15  and cavity  16  are created posteriorly. Regardless of the direction through which the vertebra  10  is operated on, in all forms, the cavity  16  which is formed is then filled with acceptable bone replacement material.  
         [0041]     Bone replacement material  19  may be one or more of the following, or any other biocompatible material judged to have the desired physiologic response:  
         [0042]     A) Demineralized bone material, morselized bone graft, cortical, cancellous, or cortico-cancellous, including autograft, allograft, or xenograft;  
         [0043]     B) Any bone graft substitute or combination of bone graft substitutes, or combinations of bone graft and bone graft substitutes, or bone inducing substances, including but not limited to: Tricalcium phosphates, Tricalcium sulfates, Tricalcium carbonates, hydroxyapatite, bone morphogenic protein, calcified and/or decalcified bone derivative; and  
         [0044]     C) Bone cements, such as ceramic and polymethylmethacrylate bone cements.  
         [0045]     The bone replacement material is inserted into the bag  22  via a needle, catheter  20  or other type of fill tool. The bone replacement material expands the bag to the limits of the cavity  16 .  
         [0046]     The inventive bag  22  may be a small fabric bag, from about one to about four cm in diameter, being roughly spherical in shape, although other elliptical shapes and other geometric shapes may be used. The bag is pliable and malleable before its interior space  21  is filled with the contents to be described. The material of the bag  22  may be configured to take on the shape of the cavity in which the bag is placed. While in this initial condition, the bag may be passed, uninflated, through a relatively small tube or portal, perhaps about three mm to about one cm in diameter.  
         [0047]     The bag  22 , such as may best be seen in  FIG. 9 , is constructed in a special and novel way. The bag  22  may be constructed of a fabric  23 . Fabric  23  may be woven, knitted, braided or form-molded to a density that will allow ingress and egress of fluids and solutions and will allow the ingrowth and through-growth of blood vessels and fibrous tissue and bony trabeculae, but the fabric porosity is tight enough to retain small particles of enclosed material, such as ground up bone graft, or bone graft substitute such as hydroxyapatite or other osteoconductive biocompatible materials known to promote bone formation. The fabric  23  defines a plurality of pores  25 . Generally, the pores  25  of the fabric  23  will have a diameter of about 0.25 mm or less to about 5.0 mm. The size is selected to allow tissue ingrowth while containing the material packed into the bag. If bone cement or other material is used which will not experience bone ingrowth, the pores  25  may be much tighter to prevent egress of the media from within the bag  22  out into the cavity  16 . This prevents leakage that could impinge upon nerves, blood vessels or the like if allowed to exit the bone.  
         [0048]     One or more of the pores  25  may be used as a fill opening  27 , wherein the fabric  23  may be manipulated to enlarge a pore to a diameter potentially greater than 5 mm but no more than about 1 cm. Preferably, the fill opening  27  is less than about 5 mm in diameter. Such a pore/fill opening  27  is sufficiently large to allow a catheter, needle, fill tube or other device for inserting or injecting fill material to pass through the fabric  23  and into the interior  21  of the bag  22  without damaging the integrity of the bag  22 .  
         [0049]     When the bag  22  is fully filled with fill material, the bag will form a self-retaining shape which substantially fills the cavity  16 . Once sufficiently full, the fill tool used to place fill material into the bag interior  21  is removed from the opening  27 . Where the opening  27  is not a pore  25  but rather a separate and distinct opening in the bag  22 , the opening  27  may have a set diameter which requires sealing such as by tying, fastening, welding, gluing or other means of closing the opening  27  after the bag has been filled. Where the opening  27  is a pore  25 , upon removal of the catheter or fill tool from the opening  27  the fabric  23  will contract to reduce the diameter of the opening  27  to be substantially similar to that of the other pores  25 .  
         [0050]     The size and density of the pores determine the ease or difficulty with which materials may pass through the mesh. For instance, very small pores (&lt;0.5 mm) would prohibit passage of all but the smallest particles and liquids. The pore size and density could be controlled in the manufacturing process, such that the final product would be matched to the needs of the surgeon. For example, if methylmethacrylate bone cement were to be used, the pore size would need to be very small, such as about less than 0.5 mm to about 1.0 mm, whereas, when bone graft or biocompatible ceramic granules are used, pore sizes ranging from about 1.0 mm to about 5.0 mm or more may be allowed. The fact that the fabric  23  is properly porous would allow it to restrict potentially dangerous flow of the fill material outside the confines of the bag.  
         [0051]     The fabric is light, biocompatible, flexible and easily handled, and has very good tensile strength, and thus is unlikely to rip or tear during insertion and inflation. When the device is inflated, the device expands to fill a previously excavated cavity  16 .  
         [0052]     The use of the term “fabric” herein is meant to include the usual definition of that term and to include any material that functions like a fabric, that is, the “fabric” of the invention must have a plurality of pores  25  through which material and fluid flow is allowed under the terms as described, and the “fabric” must be flexible enough to allow it to be collapsed and inserted into an opening smaller than the inflated bag size.  
         [0053]     The bag  22  need not be woven and may be molded or otherwise formed as is well known in the art. The preferred material may provide the ability to tailor bioabsorbance rates. Any suture-type material used medically may be used to form the bag  22 . The bag may be formed of plastic or even metal. In at least one embodiment, bag  22  is formed using a combination of resorbable and/or nonresorbable thread. Bag  22  may include a fill opening  27  which may be a bushing that could be a bioabsorbable and/or nonbioabsorbable plastic, ceramic or metal. The opening  27  may also be hydroxyapatite, or it could be plastic or metal. The opening  27  may also be characterized as a pore  25 , wherein a pore  25  of the fabric  23  has been expanded to allow a catheter  20  or other fill device to pass into the interior  21  of the bag  22 . The bag  22  could be formed from a solid material to which perforations are added. The bag  22  may be partially or totally absorbable, metal, plastic, woven, solid, film or an extruded balloon.  
         [0054]     In embodiments of the present invention a damaged tissue of a body, such as a vertebra  10  may be treated in accordance with the following procedures such as are depicted in  FIGS. 1-9 .  
         [0055]     Initially, the vertebra  10  needing repair is surgically exposed by forming at least one cavity  16 . The cavity or cavities  16  may be formed by several different means such as by reaming. Reaming may be accomplished by several means such as including the use of a reamer  14  such as, for example, the Kuslich Expandable Reamer, U.S. Pat. No. 5,015,255, the entire content of which is incorporated herein by reference. Next, the unexpanded mesh bag or Expandable Fabric Bag Device (EFBD)  22  is inserted into the cavity or cavities via catheter  20  or other means. At some point, the fill material  19  is prepared for insertion or injection into the EFBD  22 . Following preparation of the fill material  19 , the material is injected or otherwise inserted into the bag  22  using sufficient pressure to fill the bag  22  to its expanded state, thus producing rigidity and tension within the cavity or cavities  16  to reach the degree of correction required by virtue of the compression fractures. Finally, the fill opening  27  is closed to prevent egress of inflation material  19 .  
         [0056]      FIGS. 10-15  show a form of the invention in which a balloon  30  and catheter tube  32  is employed. The balloon  30  is surrounded by an expandable fabric bag  22  to protect the balloon  30  from being punctured during the inflation steps and to remain in place to prevent undesired egress of material injected into the cavity formed in the bone. Balloon  30  may be any medical-grade elastomeric balloon. The balloon  30  may be constructed from latex, urethanes, thermoplasic elastomers or other substances suitable for use as an expandable member. Examples of suitable balloons include, but are not limited to: balloons utilized with the FOGARTY.RTM. occlusion catheter manufactured by Baxter Healthcare Corporation of Santa Ana, Calif.; balloons of the type described in U.S. Pat. No. 5,972,015 to Scribner et al., and others. The methods involve placement of the expandable fabric bag  22  of the invention about the balloon 30 of the Scribner et al. device. The expandable bag  22  is left in place before the cavity  16  is filled with bone substitute or bone cement. The expandable fabric bag  22  prevents breakage of the balloon  30  and greatly limits the ability of fill material from leaking out of the cavity through bone fissures where it could cause damage.  
         [0057]     As may best be seen in  FIGS. 11, 13  and  15 , the bag  22  may include a neck  29  which extends outwardly from the bag  22  to completely overlap the shape of balloon  30 . The bag  22  and/or balloon  30  may each have a variety of shapes and sizes.  
         [0058]     If desired, the expandable fabric bag  22  may be used as the sole inflation device, eliminating the Scribner et al. balloon  30  if the fabric porosity is tight and the inflation media is reasonably viscous.  
         [0059]     While many of the previous embodiments have described the use of the bag  22  for repair of tissue such as a spinal body, in  FIGS. 16-18  show how the bag  22  may be used in treating avascular necrosis of the femoral head. In  FIG. 16 , a femoral head  40  is shown which is in need of repair.  FIG. 17  shows the femoral head being reamed out with a reamer  14 , such as previously described. The reamer  14  forms a cavity  16 . In  FIG. 18 , a bag  22  is shown within the cavity  16  formed within the femoral head  40 . The opening  27  of the bag  22  is closed off after being filled and expanded with bone substitute material.  
         [0060]     In an alternative embodiment, the Scribner et al. balloon, as previously described, may also be used with the bag  22  for repair of the femoral head  40 .  
         [0061]     Turning to an embodiment of the invention shown in  FIGS. 19-21 , a tibial plateau  48  is shown having a fracture  50 . The fracture  50  is repaired by forming a cavity  16  with a reamer  14 , such as is shown in  FIG. 20 . As is shown in  FIG. 21 , once cavity  16  is properly reamed, bag  22  may be inserted therein and filled with bone repair media  19 .  
         [0062]     Other tissue and bone abnormalities may also be treated with the inventive methods and bag  22  described herein. The present invention is not limited to only treatment of spinal bodies, femoral heads, and tibial plateaus. The bag  22  and the methods of treatment described herein, may be utilized throughout a mammalian body to treat many types of bone and tissue abnormalities including those described herein as well as others.  
         [0063]     In addition to being directed to the specific combinations of features claimed below, the invention is also directed to embodiments having other combinations of the dependent features claimed below and other combinations of the features described above.  
         [0064]     The above disclosure is intended to be illustrative and not exhaustive. This 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 claims where the term “comprising” means “including, but not limited to.” 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.  
         [0065]     Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g., each claim depending directly from claim  1  should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below (e.g., claim  3  may be taken as alternatively dependent from claim  2 ; claim  5  may be taken as alternatively dependent on claim  3 , claim  6  may be taken as alternatively dependent from claim  3 ; claim  7  may be taken as alternatively dependent from claims  3 ,  5  or  6 ; etc.).  
       BACKGROUND OF THE INVENTION  
       [0066]     1. Field of the Invention  
         [0067]     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.  
         [0068]     2. Description of the Related Art  
         [0069]     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.  
         [0070]     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.  
         [0071]     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:  
         [0000]     U.S. Pat. No. Inventor(s): 6,200,320 B1 Michelson  
         [0072]     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.  
         [0073]     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.  
         [0074]     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.  
         [0075]     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.  
         [0076]     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.  
         [0077]     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  
       [0078]     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.  
         [0079]     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.  
         [0080]     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  
       [0081]     A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:  
         [0082]      FIG. 22  is a perspective view of an embodiment of the invention;  
         [0083]      FIG. 23  is a cut-away side view of an embodiment of the invention in the non-actuated position;  
         [0084]      FIG. 24  is a cut-away side view of the embodiment of the invention shown in  FIG. 2  in the actuated position;  
         [0085]      FIG. 25  is a side view of the distal end of an embodiment of the invention wherein the pivoting action of the cutter beam is illustrated;  
         [0086]      FIG. 26  is a perspective view of the linkage assembly of the distal end of the reamer tool shown in  FIG. 4 ;  
         [0087]      FIG. 27  is a top-down view of an embodiment of the cutter beam;  
         [0088]      FIG. 28  is a cut-away side view of a two handed embodiment of the invention in a non-actuated position;  
         [0089]      FIG. 29  is cut-away side view of a two handed embodiment of the invention in an actuated, cutting position; F  
         [0090]      FIG. 30  is a side view of a serrated cutting beam;  
         [0091]      FIG. 31  is an end view of the serrated cutting beam of  FIG. 9 ;  
         [0092]      FIG. 32  is an enlarged side view of the end of the tool showing the cutting beam attachment;  FIG. 33  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;  
         [0093]      FIG. 34  is a top view of a vertebral body showing one location where the tool can enter and provide reaming; and  
         [0094]      FIG. 35  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  
       [0095]     As may be seen in  FIG. 220  the reamer tool, indicated generally at  100  may be thought of as being comprised of three main portions: a proximal portion  120 , a middle portion  140 , and a distal portion  160 .  
         [0096]     As may be seen in  FIGS. 23 and 24 , the proximal or handle portion  120  consists of a handle body  200 , a handle body lever  220 , a rack  240  and pinion  260 , a pinion handle lever  280 , a shoulder bolt  300 , and a biasing member or return spring  320 . The middle portion  140  consists of a shaft tube  400  through which a drive rod  420  is longitudinally actuated. The drive rod  420  is engaged to the distal end  500  (as may be seen in  FIG. 25 ) of the rack  240 . When a gripping action supplied by a user (not shown) pivotally actuates the pinion handle lever  280  about the pivot member  340 , the teeth  360  of the pinion  260  engage the teeth  380  of the rack  240  resulting in the back and forth movement of the drive rod  420  within the shaft tube  400 . As indicated by arrows  440  and  460  the actuation of the pinion handle lever  280  resulting from a compressive force supplied by a user will move the drive rod  420  distally such as shown in  FIG. 24 , or proximally when the force is removed, as is shown in  FIG. 23 . The position of the pinion handle lever  280  relative to the handle lever  220 , and thus the position of the drive rod  420 , will depend on the extent of the compressive force supplied by a user to the pinion handle lever  280  and handle body lever  220 .  
         [0097]     In  FIG. 23  the reamer  100  is shown in the at rest or non-actuated position. The shoulder bolt  300  is engaged to the proximal end  520  of the rack  240 . The biasing member or return spring  320  is disposed about a bolt shaft  540  which extends proximally from the rack  240  passing through a return member  580 . The bolt shaft  540  ends in an enlarged spring retaining portion  560  of the shoulder bolt  300 . The return spring  320  is biasedly engaged between the spring retaining portion  560  of the shoulder bolt  300  and the return member  580 . This return spring exerts a force sufficient to keep the drive rod  420  extended distally. The force exerted by the return spring  320  is overcome when the pinion handle lever  280  is engaged by the gripping action of the user previously described and shown in  FIG. 24 . When the user&#39;s grip is relaxed the force exerted by the return spring  320  against the spring retaining portion  560  and the return member  580  will place the reamer back in the at rest position shown in  FIG. 23 . 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.  
         [0098]     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. 22-24 , the proximal end  120  contains only one handle body lever  220  and one pinion lever  280 . This embodiment is designed for single-handed operation. However, in at least one alternative embodiment, shown in  FIGS. 28 and 29  the reamer tool may be designed for two-handed actuation. As may be seen, a two handed reamer tool  100  has a the proximal end  120  having a handle body lever  220  which is equipped with opposing grip portions  900  and  920 , as well as a pinion lever  280  having opposed section  940  and  960  as well. The present embodiment of the reamer tool  100  may be designed in such a manner that in order to rotate the cutter  600  an two handed grip of alternating action is required to actuate the opposing grips and lever sections  900 ,  940  and  920 ,  960  respectively.  
         [0099]     Turning to  FIG. 25 , the distal portion or end  160  of the reamer  100  contains the reamer head or cutting beam  600 . The beam has a plurality of cutting surfaces  610 . In the embodiment shown, the cutting blades are located at the both ends  860  and  880  of the beam. The beam  600  is pivotally connected to a handle body extension  620  by a lower pivot member  640 .  
         [0100]     The beam  600  is also engaged to the a distal end  660  of the drive rod  420  via linkage assembly  680 . The linkage assembly  680  comprises a pair of beam engagement projections  700 , as best shown in  FIG. 26 , which are disposed about the linkage tab  720  of the beam  600 , as best shown in  FIG. 27 . As may be seen in  FIG. 25 , a proximal pivot member  740  passes through the linkage tab  720  and the beam engagement projections  700 . As may be seen in  FIG. 26 , the linkage assembly  680  also includes a pair of rod engagement projections  780 . As shown in  FIG. 25 , a distal pivot member  760  passes through the pair of rod engagement projections  780  as well as the distal end  660  of the drive rod  420 . As indicated by arrows  800 , the unique arrangement of the beam  600  to the drive rod  420  and extension  620  via the linkage assembly  680  provides the reamer  100  with the ability to rotate the beam  600  about the lower pivot member  640  when the drive rod  420  is distally extended in the manner previously described. When the beam  600  is rotated, the cutting edges  610  will cut into and abrade any tissue which is encountered by the moving cutting edges  610 .  
         [0101]     As may be seen in  FIG. 27 , the cutting edges  610  are positioned on both ends  860  and  880  of the beam  600  and may be on opposing sides of the beam  600 , such as may be seen in  FIG. 25 . In the present embodiment shown in  FIG. 27 , the cutting blades  610  may be curved about the shape of a semi-circle, however, the blades  610  may also be provided with other shapes as desired. In addition, the entire perimeter  820  of the beam  600 , or a portion thereof, may include bladed portions  610  which extend beyond the semi-circle shape to form a “U” shape, such that cutting may occur along the lateral edges  630  of the perimeter  820  as well as the semi-circular ends  860  and  880 . As a result, the reamer  100  may be configured to provide a variety of cutting options which will provide a smooth uniform resecting action as the beam  600  rotates back an forth as indicated by arrows  800  in  FIG. 25 .  
         [0102]     In another embodiment of the invention the beam  600  may include one or more backward cutting blades  650 , as is shown in  FIG. 25 , allowing cutting in both the forward and reverse directions.  
         [0103]     The reamer  100  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  100  may be used in the following manner.  
         [0104]     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.  
         [0105]     The distal end  160  of the reamer  100  is then placed into the disc to the full depth of the drilled hole. The reamer  100  is oriented such that its beam  600 , with attached cutting blades  610 , is parallel to the transverse plane of the disc.  
         [0106]     The application of a manual compression force, such as by gripping the pinion lever  280  toward the handle body lever  220  forces the drive rod  420  in the distal direction. This causes the beam  600  to rotate in an elliptical manner around the lower pivot member  640 . As is shown in  FIG. 25 , the beam  600  may be pivotally displaced at least 90 degrees when the pinion lever  280  is actuated such as may be seen in  FIG. 24 . The cutter will typically provide more than 100 degrees of cutting. This motion causes the cutting blades  610  (and  630 ) to move against any intervening tissue, cleanly cutting that tissue. The return spring  320  forces the drive rod  420  and the beam  600  back to their original and respective non-actuated positions when the pinion lever  280  is relaxed, such as may be seen in  FIG. 23 . 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  100  may then be reoriented 180 degrees, so that the opposite side of the disc can be debrided.  
         [0107]     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  600  may be seen to employ one or more straight edge blades on the cutting edges  61 . Alternatively, one or more of the cutting edges  610  may also have serrated teeth  900  such as may be seen in  FIGS. 30 and 31 .  
         [0108]     As may best be seen in  FIG. 32 , when the reamer tool  100  is in the at rest or non-actuated position, the cutter beam  600  is maintained in a position such that the distal end  160  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. 25 . The reduced profile of the non-actuated distal end is sufficiently small to allow insertion of the distal end  160  into a small space or cavity  100  such as is shown in  FIG. 33 .  
         [0109]     In  FIGS. 33-34 , the reamer tool  100  is seen in use in merely one of a myriad of potential uses. As presently shown, the distal end  160  of the reamer tool  100  may be inserted into an opening or cavity  1000  of a spinal body  1020 . As the cutter beam  600  is actuated, such as previously described, the cutting surfaces  610  abrade the surrounding tissue  1040  to form a transverse cavity  1060 . Alternatively, the reamer tool  100  may be used to resect tissue from a spinal body  1020  in the middle of a vertebral compression fracture, such as may best be seen in  FIG. 35 .  
         [0110]     After the cavity has been formed, the tool  100  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. 35 .  
         [0111]     In addition to the uses described above, the various embodiments of the reamer tool  100  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.  
         [0112]     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.  
         [0113]     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.  
         [0114]     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.