Detachment mechanisms for implantable devices

Abstract

Disclosed herein are detachment mechanisms for vaso-occlusive devices that allow for rapid operator-controlled release of the vaso-occlusive device into the selected site. Also disclosed are vaso-occlusive assemblies comprising these detachment mechanisms and methods of using these detachment mechanisms and vaso-occlusive assemblies.

1 . A detachment mechanism for an implantable device, the detachment mechanism comprising:
 at least one material that changes configuration upon application of heat or electrical energy, wherein the change in configuration releases the implantable device, and further wherein if the material extends into a lumen of the implantable device, the material directly contacts at least a portion the implantable device.   
   
   
       2 . The detachment mechanism of  claim 1 , wherein the change in configuration comprises a reduction in diameter and/or volume of the material. 
   
   
       3 . The detachment mechanism of  claim 1 , wherein the change in configuration comprises an expansion in diameter and/or volume of the material. 
   
   
       4 . The detachment mechanism of  claim 1 , wherein the change in configuration comprises a deflection of the detachment mechanism. 
   
   
       5 . The detachment mechanism of  claim 1 , wherein the detachment mechanism comprises an electroactive polymer. 
   
   
       6 . The detachment mechanism of  claim 5 , wherein the detachment mechanism further comprises a metal or polymer and wherein the electroactive polymer is layered onto the metal or polymer. 
   
   
       7 . The detachment mechanism of  claim 1 , wherein the detachment mechanism comprises a layered strip of two or more metals of dissimilar thermal coefficients. 
   
   
       8 . The detachment mechanism of  claim 7 , wherein the layered strip is wound into a spiral shape. 
   
   
       9 . The detachment mechanism of  claim 1 , wherein the at least one material that changes configuration directly contacts a source of electric or heat energy. 
   
   
       10 . The detachment mechanism of  claim 1 , wherein the detachment mechanism directly engages the vaso-occlusive device. 
   
   
       11 . The detachment mechanism of  claim 1 , wherein the detachment mechanism contacts a structure attached to the implantable device. 
   
   
       12 . A detachment mechanism adapted to detachably engage a vaso-occlusive device, the detachment mechanism comprising
 an element that changes configuration upon application of electrical current or heat; and   means for applying electrical current or heat to the change the configuration of the element.   
   
   
       13 . A vaso-occlusive assembly comprising
 a vaso-occlusive device;   a detachment mechanism according to  claim 1 ; and   a source of electrical current or a heat source in contact with the detachment mechanism.   
   
   
       14 . The vaso-occlusive assembly of  claim 13 , wherein the vaso-occlusive device comprises a helically wound vaso-occlusive coil. 
   
   
       15 . The vaso-occlusive assembly of  claim 13 , further comprising a delivery mechanism. 
   
   
       16 . The vaso-occlusive assembly of  claim 15 , wherein the delivery mechanism comprises a stopper element. 
   
   
       17 . A vaso-occlusive assembly comprising
 a vaso-occlusive device;   a detachment mechanism according to  claim 12 ; and   a source of electrical current or a heat source in contact with the detachment mechanism.   
   
   
       18 . A method of at least partially occluding an aneurysm, the method comprising the steps of
 introducing a vaso-occlusive assembly according to  claim 13 , into the aneurysm, wherein the detachment mechanism engages the vaso-occlusive device; and   changing the configuration of the detachment mechanism by applying or removing electrical current or thermal energy such that the detaching mechanism releases the vaso-occlusive device into the aneurysm.