Aneurysm treatment coils

Abstract

Systems and devices for endovascular treatment of intracranial aneurysms are described. Various configurations of coiled implants may be used as stenting devices or aneurysm coils. The implants include one or more filaments wound about a longitudinal axis to form a generally tubular shape. Lateral flexibility of the implants may be manipulated by, for example, adjusting a pitch between adjacent filaments, using different materials for the filaments, employing different filament cross-sectional shapes, grouping filaments into pluralities of varying flexibilities, and nesting inner coils within outer coils.

1 .- 121 . (canceled) 
     
     
         122 . An implantable device, comprising:
 a coil comprising at least one filament, the coil forming a first region, a second region, a third region, and a fourth region axially-spaced along a length of the coil, wherein a first maximum cross-sectional dimension of the first region and the third region is greater than a second maximum cross-sectional dimension of the second region and the fourth region.   
     
     
         123 . The implantable device of  claim 122 , wherein the first region, the second region, the third region, and the fourth region are contiguous portions of the coil, wherein the second region is axially between the first region in the third region and the third region is axially between the second region of the fourth region. 
     
     
         124 . The implantable device of  claim 122 , wherein the first region, the second region, the third region, and the fourth region form a pattern that is repeated along the length of the coil. 
     
     
         125 . The implantable device of  claim 122 , wherein a transition region is defined between axially adjacent pairs of the first region, the second region, the third region, and the fourth region. 
     
     
         126 . The implantable device of  claim 125 , wherein each transition region may provide a step-wise transition from the first maximum cross-sectional dimension to the second maximum cross-sectional dimension. 
     
     
         127 . The implantable device of  claim 126 , wherein the transition region occurs over an axial length spanning one winding of the at least one filament. 
     
     
         128 . The implantable device of  claim 127 , wherein the coil further forms a fifth region at a distal end of the coil, the fifth region having a third maximum cross-sectional dimension that is greater than the second maximum cross-sectional dimension, wherein a tapering region is defined between the fourth region and the fifth region to gradually transition from the second maximum cross-sectional dimension to the third maximum cross-sectional dimension, wherein the tapering region occurs over an axial length spanning two or more windings of the at least one filament. 
     
     
         129 . The implantable device of  claim 125 , wherein the transition region occurs over an axial length spanning two or more windings of the at least one filament. 
     
     
         130 . The implantable device of  claim 122 , wherein the first diameter is sufficiently large such that the first region and the second region are able to at least partially receive the second region and/or the fourth region therein. 
     
     
         131 . The implantable device of  claim 130 , wherein, when the coil is axially compressed, the second and fourth regions are able to be axially pressed a distance into the respective inner lumens defined by the first region and the third region. 
     
     
         132 . The implantable device of  claim 122 , wherein the first region has a first axial length, the second region has a second axial length, the third region has a third axial length, and the fourth region has a fourth axial length, wherein the first and third axial lengths are different than either of the second or fourth axial lengths. 
     
     
         133 . The implantable device of  claim 122 , wherein the first region has a first axial length, the second region has a second axial length, the third region has a third axial length, and the fourth region has a fourth axial length, wherein the first axial length is different than the third axial length. 
     
     
         134 . The implantable device of  claim 122 , wherein the first region has a first axial length, the second region has a second axial length, the third region has a third axial length, and the fourth region has a fourth axial length, wherein the second axial length is different than the fourth axial length. 
     
     
         135 . The implantable device of  claim 122 , wherein one or more of the first region, the second region, the third region, and the fourth region each has a first transition region on a first side thereof and a second transition region on a second side thereof, wherein the first transition region and the second transition region each provides a transition from the first maximum cross-sectional dimension to the second maximum cross-sectional dimension, wherein the first transition region spans a first axial distance, and wherein the second transition region spans a second axial distance that is greater than the first axial distance. 
     
     
         136 . The implantable device of  claim 122 , wherein an inner cross-sectional dimension of inner lumens defined by the first region and the third region is greater than a second maximum cross-sectional dimension of the second region and the fourth region. 
     
     
         137 . A method, comprising:
 delivering an implantable device to a target site, the a device comprising a coil with at least one filament, the coil forming a first region, a second region, a third region, and a fourth region axially-spaced along a length of the coil, wherein a first maximum cross-sectional dimension of the first region and the third region is greater than a second maximum cross-sectional dimension of the second region and the fourth region.   
     
     
         138 . The method of  claim 137 , further comprising, upon application of a lateral force to the coil, bending the coil at the first region before bending at the second region. 
     
     
         139 . The implantable device of  claim 137 , further comprising, upon application of an axially compressive force, pressing the second and fourth regions a distance into the respective inner lumens defined by the first region and the third region. 
     
     
         140 . The implantable device of  claim 137 , wherein a transition region is defined between axially adjacent pairs of the first region, the second region, the third region, and the fourth region. 
     
     
         141 . The implantable device of  claim 140 , wherein the transition region occurs over an axial length spanning one winding of the at least one filament.