Methods, systems and devices for reducing migration

Abstract

Devices, systems and methods for reducing migration of leads, catheters and similar devices are provided. In particular, devices, systems and methods are provided for creating a slack anchor which assists in maintaining the lead or catheter in a desired position. In some embodiments, the slack anchor is created within the epidural space. When targeting nerve anatomy within the spinal column or in the vicinity of the epidural space, anchoring within the epidural space allows the associated lead or catheter to be anchored as close to the target therapy site as desired or possible. By anchoring close to the target therapy site, the risk of movement or migration is significantly reduced or eliminated.

1 . A method of creating a slack anchor comprising:
 positioning a lead having a distal end and a shaft so that the distal end is positioned at a target location and the shaft extends along a first path;   advancing a sheath having a curved distal end over the shaft;   manipulating the sheath so that the curved distal end directs a portion of the shaft lateral to the first path; and   advancing the lead beyond the curved distal end directing the portion of the shaft lateral to the first path so that the portion of the shaft resides along a second path forming the slack anchor while substantially maintaining position of the distal end at the target location.   
     
     
         2 . A method as in  claim 1 , wherein the slack anchor is firmed within an epidural space. 
     
     
         3 . A method as in  claim 1 , wherein the second path has a serpentine shape. 
     
     
         4 . A method as in  claim 1 , wherein the second path has a loop shape. 
     
     
         5 . A method as in  claim 1 , wherein the target location comprises a dorsal root ganglion. 
     
     
         6 . A method as in  claim 5 , wherein the slack anchor is formed at a location within the spinal column near the dorsal root ganglion. 
     
     
         7 . A method as in  claim 1 , wherein the slack anchor creates sufficient friction to resist migration of the distal end in relation to the target location. 
     
     
         8 . A method as in  claim 1 , wherein migration movement of the shaft is at least partially absorbed by the slack anchor to resist migration of the distal end in relation to the target location. 
     
     
         9 . A method of positioning a lead within an epidural space comprising:
 advancing a distal end of the lead from an entry point into the epidural space to a target location so that a portion of a shaft of the lead extends from the entry point to the target location along a first path within the epidural space; and   introducing an additional portion of the shaft of the lead into the epidural space in a manner that forms a slack anchor between the target location and the entry point.   
     
     
         10 . A method as in  claim 9 , wherein the slack anchor creates sufficient friction to resist migration of the distal end in relation to the target location. 
     
     
         11 . A method as in  claim 9 , wherein migration movement of the shaft is at least partially absorbed by the slack anchor to resist migration of the distal end in relation to the target location. 
     
     
         12 . A method as in  claim 9 , wherein introducing the additional portion comprises positioning the additional portion of the shaft of the lead along a second path, wherein at least part of the second path is lateral to the first path. 
     
     
         13 . A method as in  claim 9 , wherein the slack anchor has a serpentine shape. 
     
     
         14 . A method as in  claim 9 , wherein the slack anchor has a loop shape. 
     
     
         15 . A method as in  claim 9 , wherein the shaft includes a kink point and wherein introducing the additional portion of the shaft causes the shaft to bend near the kink point which assists in creating the slack anchor. 
     
     
         16 . A method as in  claim 9 , further comprising advancing a sheath having a curved distal end over the portion of the shaft so that the curved distal end directs the introduction of the additional portion. 
     
     
         17 . A method as in  claim 16 , further comprising manipulating the curved distal end to direct the introduction of the additional portion in a direction that is substantially lateral to the first path. 
     
     
         18 . A method as in  claim 9 , wherein the target location comprises a dorsal root ganglion. 
     
     
         19 . A method as in  claim 18 , wherein the slack anchor is formed at a location within the spinal column near the dorsal root ganglion. 
     
     
         20 . A device for treating a target location comprising:
 a lead comprising a shaft having at least one electrode disposed along its distal end and a structural kink point disposed along the shaft proximal to the at least one electrode so that the structural kink point resides within an epidural space while the at least one electrode is positioned near the target location,   wherein the structural kink point assists in creating a slack anchor when a portion of the shaft is advanced into the epidural space while the position of the at least one electrode is substantially maintained near the target location.   
     
     
         21 . A device as in  claim 20 , wherein the structural kink point comprises a change in material stiffness. 
     
     
         22 . A device as in  claim 21 , wherein the structural kink point comprises a flexible region disposed distally to a more rigid region. 
     
     
         23 . A device as in  claim 22 , wherein the shaft is comprised of at least one tube and the more rigid region is formed by potting of the at least one tube. 
     
     
         24 . A device as in  claim 20 , wherein the distal end of the lead is configured for positioning the at least one electrode near a dorsal root ganglion. 
     
     
         25 . A device as in  claim 24 , wherein structural kink point is disposed so as to create the slack anchor adjacent to a dorsal root associated with the dorsal root ganglion. 
     
     
         26 . A device as in  claim 20 , wherein the slack anchor has a serpentine shape. 
     
     
         27 . A device as in  claim 20 , wherein the slack anchor has a loop shape.