Resorbable hollow devices for implantation and delivery of therapeutic agents

Abstract

A method of manufacturing a resorbable balloon designed to contain bone cement for vertebroplasty or kyphoplasty applications is described. The resorbable balloon can be inserted into a vertebral body following vertebral cavitation and filled with bone cement. The balloon remains in place in the vertebral body and resorbs over time. Methods and apparatus are also described for delivering therapeutic agents using collapsible, resorbable balloons. The balloons may be nested and filled with various therapeutic agents that are released over time at rates dependent upon structures and degradation rates of the balloons. Furthermore, the function of the hollow devices can encompass both encapsulation and therapeutic substance delivery roles simultaneously.

1 . A method of forming a resorbable balloon, comprising:
 placing a resorbable tube in a mold, the tube having two side parts and a region therebetween with a lumen and a lumen axis, and having a wall thickness of about 0.1 mm to about 3 mm;   performing one or more of heating and cooling of the region and pulling the tube along the axis, thereby thinning the wall of the tube at the region, wherein the performing comprises cooling;   forcing a gas or liquid through the lumen while heating the region, thereby causing the region to expand and form a balloon with the wall thickness being reduced to about 0.005 mm to about 0.1 mm;   sealing one of the side parts in proximity to the balloon so that the lumen is obstructed only at the side part; and   inserting a nonporous resorbable hollow device through the lumen near the other side part and into the balloon, the device being catheterless, expandable, and having a cavity extending from a first portion that is sealed to a second portion that is coaxial with the other side part.   
     
     
         2 . The method as set forth in  claim 1 , wherein the performing is preceded by:
 extruding resorbable tubing; and   cutting the extruded tubing to desired lengths, thereby forming the tube.   
     
     
         3 . The method as set forth in  claim 1 , wherein the one side part is sealed before forcing a gas or liquid through the lumen of the tube. 
     
     
         4 . The method as set forth in  claim 3 , wherein:
 the sealing comprises at least one of thermally welding or heat sealing the tube; and   the sealing is followed by removing excess tubing beyond the sealed point.   
     
     
         5 . The method as set forth in  claim 1 , wherein the performing comprises providing heat from an element in different, non-zero amounts along a direction of the element that is about parallel to the longitudinal axis of the tube. 
     
     
         6 . The method as set forth in  claim 1 , wherein the liquid or gas is heated air. 
     
     
         7 . A method of forming a resorbable balloon, comprising:
 providing a resorbable tube;   supplying with an element one or more of heating and cooling emissions to a region of the resorbable tube, the region being disposed along a longitudinal axis of the resorbable tube and corresponding to a supplying portion of the element, the one or more of heating and cooling emissions being supplied from the supplying portion in different amounts along a dimension that is about parallel to the longitudinal axis and impinging on the region in different amounts along the longitudinal axis, wherein the supplying comprises cooling;   forcing a gas or liquid through a lumen of the resorbable tube while supplying the one or more of heating and cooling emissions to the region of the resorbable tube, thereby causing a portion of the resorbable tube to expand and form a balloon; and   disposing a nonporous resorbable hollow device in the lumen and the balloon, the device being catheterless, expandable, and having a cavity that extends without obstruction along the longitudinal axis from a sealed end to an opposing end and that is coaxial with the lumen whereby the cavity is obstructed only at the sealed end.   
     
     
         8 . The method as set forth in  claim 7 , wherein the supplying comprises heating the region of the resorbable tube, the heating emissions contacting the region in different amounts along the longitudinal axis of the resorbable tube. 
     
     
         9 . The method as set forth in  claim 7 , wherein:
 the providing comprises proving the resorbable tube with a wall thickness ranging from about 0.1 mm to about 3 mm; and   the forcing comprises forming a balloon with the wall thickness being reduced from the range of 0.1 mm to about 3 mm to a range from about 0.005 mm to about 0.1 mm.   
     
     
         10 . The method as set forth in  claim 9 , wherein the supplying and the forcing are performed in a single mold. 
     
     
         11 . The method as set forth in  claim 9 , wherein the supplying is performed by cooling the region of the resorbable tube, the cooling emissions contacting the region in different amounts along the longitudinal axis of the resorbable tube. 
     
     
         12 . The method as set forth in  claim 7 , wherein the supplying comprises heating the region of the resorbable tube, the heating emissions contacting the region in different amounts along the longitudinal axis of the resorbable tube. 
     
     
         13 . The method as set forth in  claim 12 , wherein the supplying and the forcing are performed in the same mold. 
     
     
         14 . The method as set forth in  claim 7 , wherein the supplying comprises heating. 
     
     
         15 . The method as set forth in  claim 7 , wherein the supplying comprises heating, which is preceded by:
 extruding resorbable tubing;   cutting tubing to desired lengths, thereby forming the plurality of resorbable tubes; and   the element is a heating coil with different resistances along the supplying portion thereof for causing the one or more heating and cooling emissions to be supplied from the supplying portion in different amounts along the dimension.   
     
     
         16 . The method as set forth in  claim 7 , wherein the supplying is performed by cooling the region of the resorbable tube, the cooling emissions being provided in different amounts along the longitudinal axis of the resorbable tube. 
     
     
         17 . A method of forming a resorbable balloon, comprising:
 providing a resorbable tube;   generating one or more of heating and cooling emissions along a first dimension of an element, the element having a longitudinal axis that is about parallel with the first dimension, and the one or more of heating and cooling emissions being received by the resorbable tube along a second dimension of the resorbable tube that is about parallel to a longitudinal axis of the resorbable tube, the one or more of heating and cooling emissions being generated in different amounts along the first dimension of the element, wherein an orientation of the longitudinal axis of the element is about the same as an orientation of the longitudinal axis of the resorbable tube, wherein the generating comprises cooling;   forcing a gas or liquid through a lumen of the resorbable tube while generating the one or more of heating and cooling emissions, thereby causing a portion of the resorbable tube to expand and form a balloon; and   inserting a nonporous resorbable device through the lumen and into the balloon, the device being catheterless and expandable, and having two opposing ends and an unobstructed hollow interior extending therebetween along the longitudinal axis and coaxially with the lumen.   
     
     
         18 . The method as set forth in  claim 17 , wherein:
 the providing comprises proving the resorbable tube with a wall thickness ranging from about 0.1 mm to about 3 mm; and   the forcing comprises forming a balloon with the wall thickness being reduced from the range of 0.1 mm to about 3 mm to a range from about 0.005 mm to about 0.1 mm.   
     
     
         19 . The method as set forth in  claim 17 , wherein the generating and the forcing are performed in a single mold. 
     
     
         20 . The method as set forth in  claim 17 , wherein the element is a coil with different resistances along the first dimension thereof for causing the one or more heating and cooling emissions to be generated in different amounts along the first dimension.