Micromachined medical devices

Abstract

Medical devices that include micromachined hypotubes or that have themselves been micromachined can provide advantages in flexibility, strength and other desirable properties. Examples of such medical devices may include catheters such as guide catheters and balloon catheters. Such devices may also include dual shaft medical devices in which an outer shaft is reversibly lockable onto an inner shaft.

1 . (canceled) 
     
     
         2 . A medical device comprising:
 an outer shaft having a proximal end and a distal end;   an inner shaft movably disposed within the outer shaft, a distal end of the inner shaft extending beyond the distal end of the outer shaft; and   an actuatable means for locking the inner shaft to the outer shaft, thereby preventing relative movement therebetween;   wherein the means for locking is fixedly attached to the outer shaft.   
     
     
         3 . The medical device of  claim 2 , wherein the means for locking includes a collapsible cage disposed over the inner shaft, the collapsible cage comprising a first end attached to the distal end of the outer shaft and a second end attached to at least one attachment point on the inner shaft;
 wherein the collapsible cage is actuatable between a unlocked position in which the outer shaft may translate with respect to the inner shaft and a locked position in which the outer shaft is locked to the inner shaft and cannot translate.   
     
     
         4 . The medical device of  claim 3 , wherein the collapsible cage comprises a plurality of strands, each strand having a first end attached to the distal end of the outer shaft and a second end attached to one attachment point on the inner shaft. 
     
     
         5 . The medical device of  claim 3 , wherein the collapsible cage is configured to be actuatable between the unlocked position and the locked position by rotating the outer shaft a predetermined distance with respect to the inner shaft. 
     
     
         6 . The medical device of  claim 4 , wherein each of the plurality of strands is formed of a metallic wire. 
     
     
         7 . The medical device of  claim 6 , wherein each of the plurality of strands is attached to the outer shaft and the inner shaft by welding or soldering. 
     
     
         8 . The medical device of  claim 2 , wherein the means for locking includes a polymer sleeve disposed over the inner shaft, the polymer sleeve comprising a first end attached to the distal end of the outer shaft and a second end attached to an attachment point on the inner shaft;
 wherein the polymer sleeve is actuatable between an unlocked position in which the outer shaft may translate with respect to the inner shaft and a locked position in which the outer shaft is locked to the inner shaft and cannot translate.   
     
     
         9 . The medical device of  claim 8 , wherein the polymer sleeve comprises an electro-active polymer. 
     
     
         10 . The medical device of  claim 9 , wherein the polymer sleeve is actuatable from the unlocked position to the locked position by applying an electric current to the electro-active polymer, causing the polymer sleeve to constrict down onto the inner shaft. 
     
     
         11 . The medical device of  claim 10 , wherein the electric current is transmitted to the electro-active polymer via the outer shaft. 
     
     
         12 . The medical device of  claim 2 , wherein the outer shaft includes a micromachined hypotube. 
     
     
         13 . The medical device of  claim 12 , wherein the micromachined hypotube includes a plurality of flexibility-inducing slots disposed along the micromachined hypotube, the slots extending radially about the micromachined hypotube. 
     
     
         14 . The medical device of  claim 13 , wherein the plurality of flexibility-inducing slots includes a first plurality of slots having a first slot density disposed within the proximal region of the micromachined hypotube and a second plurality of slots having a second slot density disposed within the distal region of the micromachined hypotube, and the second slot density is greater than the first slot density. 
     
     
         15 . The medical device of  claim 14 , wherein the first slot density changes to the second slot density in a step-wise fashion. 
     
     
         16 . The medical device of  claim 14 , wherein the first slot density changes to the second slot density in a continuous fashion. 
     
     
         17 . The medical device of  claim 12 , wherein the micromachined hypotube includes a first plurality of slots disposed within a first portion, the slots extending at least partially circumferentially around the micromachined hypotube, and a second plurality of slots disposed within a second portion, the slots extending at least partially circumferentially around the micromachined hypotube;
 wherein the second plurality of slots include adjacent slots having a spacing therebetween that is less than a spacing between adjacent slots within the first plurality of slots.   
     
     
         18 . The medical device of  claim 17 , wherein each of the first plurality of slots extend circumferentially about half way around the micromachined hypotube. 
     
     
         19 . The medical device of  claim 17 , wherein adjacent slots within the first plurality of slots are radially offset from each other. 
     
     
         20 . The medical device of  claim 17 , wherein each of the second plurality of slots extend circumferentially about half way around the micromachined hypotube. 
     
     
         21 . The medical device of  claim 17 , wherein adjacent slots within the second plurality of slots are radially offset from each other.