Low-compliance expandable medical device

Abstract

An apparatus includes an elongate body and an expandable member coupled to the elongate body. In one embodiment, the expandable member has a collapsed configuration, an unfolded configuration and an expanded configuration. The expandable member is configured to be percutaneously inserted into an interior portion of a bone structure when the expandable member is in the collapsed configuration. The expandable member is configured to exert a pressure in a vertical direction on a first portion of the bone structure in contact with the expandable member greater than a pressure exerted in a lateral direction on a second portion of the bone structure in contact with the expandable member when the expandable member transitions from the unfolded configuration to the expanded configuration.

1 . An apparatus, comprising:
 an elongate body; and   an expandable member coupled to the elongate body, the expandable member having a collapsed configuration, an unfolded configuration and an expanded configuration, the expandable member configured to be percutaneously inserted into an interior portion of a bone structure when the expandable member is in the collapsed configuration,   the expandable member configured to exert a pressure in a vertical direction on a first portion of the bone structure in contact with the expandable member greater than a pressure exerted in a lateral direction on a second portion of the bone structure in contact with the expandable member when the expandable member transitions from the unfolded configuration to the expanded configuration.   
     
     
         2 . The apparatus of  claim 1 , wherein the expandable member is constructed with a low-compliance material. 
     
     
         3 . The apparatus of  claim 1 , further comprising:
 a cannula configured to provide percutaneous access to the interior portion of the bone structure, the elongate body configured to be movably disposed within a lumen of the cannula.   
     
     
         4 . The apparatus of  claim 1 , wherein the expandable member is configured to expand a greater distance in a direction perpendicular to a longitudinal axis defined by the elongate body than in a direction parallel to the axis. 
     
     
         5 . The apparatus of  claim 1 , wherein the expandable member in the expanded configuration is configured to move at least a portion of the interior portion of the bone structure. 
     
     
         6 . The apparatus of  claim 1 , wherein the bone structure is a vertebral body. 
     
     
         7 . The apparatus of  claim 1 , wherein the unfolded configuration is when the expandable member is partially unfolded. 
     
     
         8 . The apparatus of  claim 1 , wherein the unfolded configuration is when the expandable member is fully unfolded. 
     
     
         9 . An apparatus, comprising:
 an elongate body; and   an expandable member constructed with low-compliance material releasably coupled to the elongate body, the expandable member having a collapsed configuration and an expanded configuration, the expandable member configured to be percutaneously disposed entirely within an interior portion of a single vertebral body, the expandable member in the expanded configuration configured to be released from the elongate body and remain within the interior portion of the vertebral body after the elongate body has been removed from the vertebral body.   
     
     
         10 . The apparatus of  claim 9 , wherein the expandable member is permeable and configured to permit bone growth between at least a portion of the interior portion of the vertebral body and the expandable member. 
     
     
         11 . The apparatus of  claim 9 , wherein the expandable member in the expanded configuration is configured to move at least a portion of the interior portion of the vertebral body. 
     
     
         12 . The apparatus of  claim 9 , further comprising:
 a cannula configured to provide percutaneous access to the interior portion of the vertebral body, the elongate body configured to be movably disposed within a lumen defined by the cannula.   
     
     
         13 . The apparatus of  claim 9 , wherein the expandable member in the expanded configuration has a width dimension perpendicular to a longitudinal axis defined by the elongate body and a length dimension parallel to the longitudinal axis, the width dimension is greater than the length dimension. 
     
     
         14 . An apparatus, comprising:
 an elongate body defining a longitudinal axis; and   an expandable member constructed with low-compliance material, the expandable member configured to be disposed within an interior portion of a vertebral body, the expandable member having a collapsed configuration and an expanded configuration, the expandable member when in the expanded configuration has a width substantially perpendicular to the longitudinal axis that is greater than a length substantially parallel to the longitudinal axis, the expandable member when in the expanded configuration configured to exert a pressure on cancellous bone disposed between the expandable member and an endplate of the vertebral body.   
     
     
         15 . The apparatus of  claim 14 , further comprising:
 a cannula configured to provide percutaneous access to the interior portion of the vertebral body, the elongate body configured to be movably disposed within a lumen defined by the cannula.   
     
     
         16 . The apparatus of  claim 14 , wherein the expandable member in the expanded configuration is configured to be released from the elongate body and remain within the interior portion of the vertebral body after the elongate body has been removed from the vertebral body. 
     
     
         17 . The apparatus of  claim 14 , wherein the expandable member in the expanded configuration is configured to be released from the elongate body and remain within the interior portion of the vertebral body after the elongate body has been removed from the vertebral body,
 the expandable member being permeable and configured to permit bone growth between at least a portion of the interior portion of the vertebral body and the expandable member.   
     
     
         18 . The apparatus of  claim 14 , wherein the expandable member, when in the expanded configuration, is configured to exert a pressure on a portion of sclerotic bone within the interior portion of the vertebral body sufficient to break through the portion of sclerotic bone.