Tissue cavitation device and method

Abstract

A percutaneous surgical device and method for creating a cavity within tissue during a minimally invasive procedure. A cavitation device includes a shaft interconnected to a flexible cutting element. A flexible cutting element has a first shape suitable for minimally invasive passage into tissue. The flexible cutting element has a means to move toward a second shape suitable for forming a cavity in tissue. When used in bone, the resulting cavity is usually filled with bone cement or suitable bone replacement material that is injectable and hardens in situ. The disclosed cavitation device and methods can be used for the following applications: (1) treatment or prevention of bone fracture, (2) joint fusion, (3) implant fixation, (4) tissue harvesting (especially bone), (5) removal of diseased tissue (hard or soft tissue), and (6) general tissue removal (hard or soft tissue).

1 . A tissue cavitation device, comprising: 
 a shaft having a diameter and a longitudinal axis;    a flexible cutting element associated with said shaft;    said flexible cutting element adapted to assume a first shape substantially colinear with the longitudinal axis of said shaft and adapted to assume a second shape suitable for forming a tissue cavity having a diameter greater than the diameter of said shaft when said shaft is rotated about the longitudinal axis of said shaft; and    flexing means for biasing said flexible cutting element to move from said first shape toward said second shape.    
     
     
         2 . The device of  claim 1 , wherein said flexing means is spring bias arising from elastic deformation of said flexible cutting element when said flexible cutting element is in said first shape.  
     
     
         3 . The device of  claim 2 , wherein said flexible cutting element has a substantially quadrilateral cross-section.  
     
     
         4 . The device of  claim 2 , wherein said flexible cutting element has a substantially circular cross-section.  
     
     
         5 . The device of  claim 2 , wherein said shaft and said flexible cutting element are dimensioned to pass telescopically through the interior of an insertion tube having a proximal end and a distal end.  
     
     
         6 . The device of  claim 5 , wherein said flexible cutting element assumes said first shape when said flexible cutting element is positioned within said insertion tube, and said spring bias tends to move said flexible cutting element toward said second shape as said flexible cutting element emerges from the distal end of said insertion tube.  
     
     
         7 . The device of  claim 2 , wherein 
 said shaft has a first end and a second end;    said flexible cutting element is disposed at the second end of said shaft; and    at least a portion of said flexible cutting element moves away from the longitudinal axis of said shaft as said flexible cutting element moves from said first shape toward said second shape.    
     
     
         8 . The device of  claim 7 , wherein said flexible cutting element is rigidly connected to the second end of said shaft.  
     
     
         9 . The device of  claim 8 , wherein said flexible cutting element and said shaft are formed from a single piece of material.  
     
     
         10 . The device of  claim 9 , wherein said second shape of said flexible cutting element comprises a curvilinear are projecting away from the longitudinal axis of said shaft.  
     
     
         11 . The device of  claim 10 , wherein said shaft has a substantially circular cross-section.  
     
     
         12 .- 91 . (Cancel)  
     
     
         92 . A percutaneous surgical method for forming a cavity in tissue, comprising the steps of: 
 forming a pilot hole;    inserting into the pilot hole a tissue cavitation device, comprising: 
 a shaft having a diameter and a longitudinal axis;  
 a flexible cutting element associated with said shaft;  
 said flexible cutting element adapted to assume a first shape substantially colinear with the longitudinal axis of said shaft;  
 said flexible cutting element adapted to assume a second shape suitable for cutting a tissue cavity having a diameter greater than the diameter of said shaft when said shaft is rotated about the longitudinal axis of said shaft; and  
 flexing means for biasing said flexible cutting element to move from said first shape toward said second shape; and  
   rotary said shaft to form a cavity having a diameter greater than the diameter of said shaft.    
     
     
         93 . The method of  claim 92 , further comprising the step of removing ablated tissue using irrigation and suction.  
     
     
         94 . The method of  claim 92 , further comprising the step of moving said tissue cavitation device along the longitudinal axis of said shaft while said shaft is rotating, thereby enlarging the cavity.  
     
     
         95 . The method of  claim 92 , further comprising the step of moving said tissue cavitation device transverse to the longitudinal axis of said shaft while said shaft is rotating, thereby enlarging the cavity.  
     
     
         96 . The method of  claim 92 , further comprising the step of moving said tissue cavitation device at an angle with respect to the tissue while said shaft is rotating, thereby enlarging the cavity.  
     
     
         97 . The method of  claim 92 , further comprising the steps of: 
 withdrawing the percutaneous surgical cavitation device from the cavity; and    injecting a strengthening material into the cavity.    
     
     
         98 . The method of  claim 97 , wherein the strengthening material is polymethymethacrylate.  
     
     
         99 . The method of  claim 97 , wherein the strengthening material comprises an injectable calcium phosphate.  
     
     
         100 . The method of  claim 97 , wherein the strengthening material comprises a terpolymer resin having combeite glass-ceramic reinforcing particles.