Medical Device and Its Manufacture

Abstract

A biodegradable medical device including at least one biodegradable material and having an initial shape and at least one evolved shape. The evolved shape is different from the initial shape. The initial shape is adapted to change towards the evolved shape due to an external stimulus. The medical device has a tension loaded to a predetermined tension level. The medical device is adapted to resore the tension to the predetermined tension level for at least 2 weeks in physiological conditions, or conditions simulating the physiological conditions.

What is claimed is: 
     
         1 . A biodegradable orthopedic device for bone fracture fixation, said device being formed of one piece and comprising a continuous elongated shaft made of at least one biodegradable polymer material having an oriented polymer structure so as to have a predetermined tension level of between 5N and 260N;
 the device having an initial shape and at least one evolved shape, the at least one evolved shape being different from the initial shape, and the initial shape being adapted to change towards the at least one evolved shape due to an external stimulus, wherein the change includes a full length longitudinal shrinking and a full length radial expansion of the continuous elongated shaft, such that the full length longitudinal shrinkage of said device pulls bone fragments together thereby tightening the bone fragment fixation, and wherein the external stimulus is an aqueous environment and temperature of 35 to 42° C.   
     
     
         2 . The biodegradable orthopedic device according to  claim 1 , wherein said device is adapted to restore its tension to the predetermined tension level by change of dimensions by reducing the tension level if the bone fragment fixation is too tight or too loose. 
     
     
         3 . The biodegradable orthopedic device according to  claim 1 , wherein said device has a predetermined rate of changing from the initial shape towards the at least one evolved shape. 
     
     
         4 . The biodegradable orthopedic device according to  claim 1 , wherein said device has a predetermined shape between the initial shape and the at least one evolved shape until which it changes towards the at least one evolved shape. 
     
     
         5 . The biodegradable orthopedic device according to  claim 1 , wherein said device comprises at least one homopolymer, copolymer, or a polymer blend. 
     
     
         6 . The biodegradable orthopedic device according to  claim 5 , wherein said device comprises a copolymer of lactide and glycolide or a copolymer of D-lactide and L-lactide. 
     
     
         7 . The biodegradable orthopedic device according to  claim 6 , wherein the copolymer of lactide and glycolide comprises from 5 wt.-% to 95 wt.-% of lactide and from 95 wt.-% to 5 wt.-% of glycolide. 
     
     
         8 . The biodegradable orthopedic device according to  claim 6 , wherein the copolymer of D-lactide and L-lactide comprises from 2 wt.-% to 98 wt.-% of D-lactide and from 98 wt.-% to 2 wt.-% of L-lactide. 
     
     
         9 . The biodegradable orthopedic device according to  claim 1 , wherein the continuous elongated shaft has grooves in the at least one evolved shape. 
     
     
         10 . The biodegradable orthopedic device according to  claim 9 , wherein the grooves in the at least one evolved shape are longitudinal. 
     
     
         11 . The biodegradable orthopedic device according to  claim 9 , wherein the grooves in the at least one evolved shape are in a form of threads. 
     
     
         12 . The biodegradable orthopedic device according to  claim 9 , wherein said device comprises a head. 
     
     
         13 . The biodegradable orthopedic device according to  claim 12 , wherein said device is a screw. 
     
     
         14 . The biodegradable orthopedic device according to  claim 12 , wherein said device is a tack.