Tools and methods for creating cavities in bone

Abstract

Tools for use in the creation of cavities in bones. The tools include a probe, a cannula that provides percutaneous passageway to the interior of the treated bone, a bone tamp, and a system for delivering bone filler material into the cavity. The bone tamp has a shaft that is inserted into the bone through the cannula. The end of the shaft that is inserted into the bone may have a flapper tip that extends out of axial alignment with the shaft upon deployment by the physician. Once the tip is deployed, the bone tamp can be rotated to form the cavity. The cavity may then be treated with a medicament, filled with bone filler material, or both. Other tools and materials described herein may be used to lift or restore the treated bone closer to its natural anatomy.

We claim:  
     
         1 . A surgical instrument for piercing and cutting tissue and creating a percutaneous path to bone comprising: 
 a shaft having a longitudinal axis and proximal and distal ends having 
 a length sufficient to create a percutaneous path to bone,  
 a cross-section normal to the longitudinal axis,  
 a plurality of surfaces aligned with the longitudinal axis, and  
 a tip on the distal end of the shaft, the tip having 
 a plurality of facets that intersect to form a point for piercing tissue, at least two of the facets intersecting to form an edge for cutting tissue, and  
 at least one other surface adjoining the cutting edge,  
 
   wherein, the cross-section of the shaft varies along the length of the shaft, and a first cross-section at a first location along the length of the shaft has a first area and a second cross-section at a second location along the length of the shaft has a second area, the first area greater than the second area, and the second location is situated between the first location and the proximal end of the shaft.    
     
     
         2 . The surgical instrument of  claim 1 , wherein the first cross-section is polygonal.  
     
     
         3 . The surgical instrument of  claim 2 , wherein the second cross-section is polygonal.  
     
     
         4 . The surgical instrument of  claim 3 , wherein the first and second cross-sections have substantially similar shape.  
     
     
         5 . The surgical instrument of  claim 4 , wherein the first and second cross-sections are aligned along the longitudinal axis of the instrument.  
     
     
         6 . The surgical instrument of  claim 5 , wherein the first cross-section has a perimeter having six sides.  
     
     
         7 . The surgical instrument of  claim 1 , wherein at least one facet has a substantially planar surface.  
     
     
         8 . The surgical instrument of  claim 1 , wherein the plurality of surfaces on the shaft comprise at least two substantially planar surfaces.  
     
     
         9 . The surgical instrument of  claim 8 , wherein one or more of the plurality of surfaces on the shaft are inclined with respect to the longitudinal axis.  
     
     
         10 . The surgical instrument of  claim 9 , wherein one or more of the plurality of surfaces on the shaft are oblique with respect to the longitudinal axis.  
     
     
         11 . The surgical instrument of  claim 8 , wherein the at least two substantially planar surfaces are parallel.  
     
     
         12 . The surgical instrument of  claim 1 , wherein the shaft tapers from a third location to the second location.  
     
     
         13 . The surgical instrument of  claim 12 , wherein the third location has a third cross-section, the third cross-section having a shape different than the second cross-section.  
     
     
         14 . The surgical instrument of  claim 13 , wherein the third cross-section is non polygonal.  
     
     
         15 . The surgical instrument of  claim 14 , wherein the third cross-section comprises a curved perimeter.  
     
     
         16 . The surgical instrument of  claim 15 , wherein the third cross-section is substantially circular.  
     
     
         17 . The surgical instrument of  claim 1 , wherein the proximal end of the shaft comprises a handle attachment site.  
     
     
         18 . The surgical instrument of  claim 17 , further comprising a handle for manipulating the surgical instrument.  
     
     
         19 . The surgical instrument of  claim 18 , wherein the handle is lobe shaped.  
     
     
         20 . The surgical instrument of  claim 19 , wherein the handle is releasably secured to the handle attachment site.  
     
     
         21 . The surgical instrument of  claim 20 , wherein the handle attachment site comprises a substantially flat surface a groove.  
     
     
         22 . The instrument of  claim 1 , wherein the tip is unsymmetrical.  
     
     
         23 . The instrument of  claim 1 , wherein the shaft is substantially symmetrical.  
     
     
         24 . A surgical instrument for separating tissue and creating a percutaneous path to bone comprising: 
 a shaft having a longitudinal axis and proximal and distal ends, the shaft having 
 a length sufficient to create a percutaneous path to bone,  
 a cross-section normal to the longitudinal axis,  
 at least two surfaces substantially aligned with the longitudinal axis, and  
 a tip connected to the distal end of the shaft, the tip having 
 a plurality of facets that form a surface for separating tissue, at least two of the facets intersecting to form a curved edge, and  
 at least one other surface adjoining the curved edge and facets,  
 
 wherein, the cross-section of the shaft varies along the length of the shaft, and a first cross-section at a first location along the length of the shaft has a first area and a second cross-section at a second location along the length of the shaft has a second area, the first area greater than the second area, and the second location is situated between the first location and the proximal end of the shaft.