Expandable preformed structures for deployment in interior body regions

Abstract

An expandable structure made from an elastomer material is preformed to a desired geometry by exposure to heat and pressure. The structure undergoes controlled expansion and further distention in cancellous bone, with controlled deformation and without stress failure.

1 . A system comprising 
 a first tool establishing a percutaneous access path to a bone structure having cortical bone enclosing a cancellous bone volume,    a second tool comprising an expandable structure sized and configured to be inserted into the bone structure through the percutaneous access path, the expandable structure comprising a wall made from a flexible material and including an expandable region preformed with a normally expanded shape outside bone, the expandable region being expandable beyond its normally expanded shape to reach an inflation volume sized and configured for forming a cavity in cancellous bone, the expandable region having a proximal expanded section, a distal expanded section, and an intermediate expanded section located between the proximal and distal expanded sections, the intermediate expanded section having, when the wall is in the normally expanded shape and at the inflation volume, an average wall thickness greater than average wall thicknesses of either the first and second sections, and    a third tool to convey a filler material into the cavity.    
     
     
         2 . A system according to  claim 1   wherein expansion of the expandable structure compacts cancellous bone.    
     
     
         3 . A system according to  claim 1   wherein the filler material comprises bone cement.    
     
     
         4 . A system according to  claim 1   wherein the filler material comprises synthetic bone substitute.    
     
     
         5 . A system according to  claim 1   wherein the filler material comprises a flowable material that sets to a hardened condition.    
     
     
         6 . A system for treating bone comprising 
 a first tool establishing a percutaneous access path to a bone structure having cortical bone enclosing a cancellous bone volume,    a second tool comprising an expandable structure sized and configured to be inserted into the bone structure through the percutaneous access path, the expandable structure comprising a wall made from a flexible material and including an expandable region preformed with a normally expanded shape outside bone, the expandable region being expandable beyond its normally expanded shape to reach an inflation volume sized and configured to move fractured cortical bone, the expandable region having a proximal expanded section, a distal expanded section, and an intermediate expanded section located between the proximal and distal expanded sections, the intermediate expanded section having, when the wall is in the normally expanded shape and at the inflation volume, an average wall thickness greater than average wall thicknesses of either the first and second sections, and    a third tool to convey a filler material into the cancellous bone volume.    
     
     
         7 . A system according to  claim 6   wherein expansion of the expandable structure compacts cancellous bone.    
     
     
         8 . A system according to  claim 6   wherein expansion of the expandable structure forms a cavity in cancellous bone.    
     
     
         9 . A system according to  claim 6   wherein the filler material comprises bone cement.    
     
     
         10 . A system according to  claim 6   wherein the filler material comprises synthetic bone substitute.    
     
     
         11 . A system according to  claim 6   wherein the filler material comprises a flowable material that sets to a hardened condition.    
     
     
         12 . A method for treating bone comprising 
 establishing a percutaneous access path to a bone structure having cortical bone enclosing a cancellous bone volume,    deploying an expandable structure into the cancellous bone volume through the percutaneous access path, the expandable structure comprising a wall made from a flexible material and including an expandable region preformed with a normally expanded shape outside bone, the expandable region being expandable beyond its normally expanded shape to reach an inflation volume sized and configured to form a cavity in cancellous bone, the expandable region having a proximal expanded section, a distal expanded section, and an intermediate expanded section located between the proximal and distal expanded sections, the intermediate expanded section having, when the wall is in the normally expanded shape and at the inflation volume, an average wall thickness greater than average wall thicknesses of either the first and second sections,    expanding the structure to the inflation volume to form a cavity in the cancellous bone volume, and    conveying a filler material into the cavity.    
     
     
         13 . A method according to  claim 12   wherein the filler material comprises bone cement.    
     
     
         14 . A method according to  claim 12   wherein the filler material comprises synthetic bone substitute.    
     
     
         15 . A method according to  claim 12   wherein the filler material comprises a flowable material that sets to a hardened condition.    
     
     
         16 . A method for treating bone comprising 
 establishing a percutaneous access path to a bone structure having cortical bone enclosing a cancellous bone volume,    deploying an expandable structure into the cancellous bone volume through the percutaneous access path, the expandable structure comprising a wall made from a flexible material and including an expandable region preformed with a normally expanded shape outside bone, the expandable region being expandable beyond its normally expanded shape to reach an inflation volume sized and configured to move fractured cortical bone, the expandable region having a proximal expanded section, a distal expanded section, and an intermediate expanded section located between the proximal and distal expanded sections, the intermediate expanded section having, when the wall is in the normally expanded shape and at the inflation volume, an average wall thickness greater than average wall thicknesses of either the first and second sections,    expanding the structure to the inflation volume to move fractured cortical bone, and    conveying a filler material into the cancellous bone volume.    
     
     
         17 . A method according to  claim 16   wherein expansion of the structure compacts cancellous bone.    
     
     
         18 . A method according to  claim 16   wherein expansion of the structure forms a cavity in cancellous bone.    
     
     
         19 . A method according to  claim 16   wherein the filler material comprises bone cement.    
     
     
         20 . A method according to  claim 16   wherein the filler material comprises synthetic bone substitute.    
     
     
         21 . A method according to  claim 16   wherein the filler material comprises a flowable material that sets to a hardened condition.    
     
     
         22 . A method comprising 
 selecting a vertebral body for treatment, the vertebral body having a cortical wall enclosing a cancellous bone volume,    providing an expandable device including an expanded configuration and an unexpanded configuration, the expandable device comprising a wall made from a flexible material and including an expandable region preformed with a normally expanded shape outside bone, the expandable region being expandable beyond its normally expanded shape to reach an inflation volume sized and configured to form a cavity in cancellous bone, the expandable region having a proximal expanded section, a distal expanded section, and, an intermediate expanded section located between the proximal and distal expanded sections, the intermediate expanded section having, when the wall is in the normally expanded shape and at the inflation volume, an average wall thickness greater than average wall thicknesses of either the first and second sections to control the expansion so that the expandable device expands more in an inferior-to-superior direction than in a lateral direction,    introducing the expandable device into the vertebral body through a percutaneous access path while in the unexpanded condition, and    expanding the expandable device while disposed within the cancellous bone volume from the unexpanded configuration toward the expanded configuration to form the cavity.    
     
     
         23 . A method according to  claim 22   and further including conveying a filler material into the cavity.    
     
     
         24 . A method according to  claim 22   wherein expansion of the expandable device moves fractured cortical bone.