Soft anchors for anatomical fixation, and related systems and methods
A tissue repair assembly can transition from an insertion to an anchored configuration and includes an anchor body, actuator, and “snake.” The body and actuator comprise suture. The body defines a loop with length and width that decrease and increase, respectively, during transition to the anchored configuration. The actuator defines first and second actuation portions, the former defining a locking mechanism having knot loops within a distal interior passage of the body. The snake has a snake portion and first and second tails. In the insertion configuration: the snake portion extends through the knot loops; the second actuation portion and tails are outside the body. Tensioning the second actuation portion and/or tails transitions the assembly to the anchored configuration. The first tail can engage and pull the second actuation portion through the passage, wherein the second actuation portion is slidable through the knot loops and defines an exterior approximation loop.
1 . An assembly for anatomical approximation, wherein the assembly is configured to transition from an insertion configuration to an anchored configuration, the assembly comprising:
an anchor body constructed of suture and defining an anchor loop, the anchor body defining a length along a first direction and a width along a second direction that is substantially perpendicular to the first direction, wherein the anchor body is configured so that the length decreases and the width increases as the assembly transitions from the insertion configuration to the anchored configuration;
an actuation member that is constructed of suture and defines a first actuation portion and a second actuation portion, wherein the first actuation portion defines a locking mechanism within an interior passage defined by a distal portion of the anchor body, wherein the locking mechanism comprises a plurality of knot loops; and
a snake member having a first snake portion and first and second snake tails,
wherein, when the assembly is in the insertion configuration:
the first snake portion extends along the interior passage of the anchor body and through the plurality of knot loops,
the second actuation portion and the first and second snake tails are exterior of the anchor body, and
at least one of the second actuation portion and the first and second snake tails is configured to receive a tensile force for transitioning the assembly from the insertion configuration to the anchored configuration, and
wherein a free end region of the second snake tail is configured to couple with a free end region of the second actuation portion, such that a free end region of the first snake tail is configured to be pulled to draw the free end region of the second actuation portion into and through the interior passage of the anchor body, so that:
when the assembly is in a third configuration, the second actuation portion:
1) is gripped by and slidable relative to the plurality of knot loops within the interior passage, and
2) defines an approximation loop located exterior of the anchor body for approximating tissue.
2 . The assembly of claim 1 , wherein the plurality of knot loops comprises a first knot loop and a second knot loop.
3 . The assembly of claim 2 , wherein the first and second knot loops are defined by respective portions of the first actuation portion that are bent into loops that double back and penetrate through the first actuation portion.
4 . The assembly of claim 2 , wherein the first knot loop and the second knot loop are spaced from each other at a knot loop spacing distance measured along a central axis of the anchor body, and the knot loop spacing distance is in a range of about 2.0 mm to about 7.0 mm.
5 . The assembly of claim 4 , wherein the knot spacing distance is in a range of about 3.5 mm to about 4.5 mm.
6 . The assembly of claim 1 , wherein the second actuation portion comprises first and second actuation tails that extend outside the anchor body from first and second locations of the anchor body, respectively, and the first and second actuation tails are spliced together extending from a splice insertion point to a splice end point, wherein the splice insertion point is located within a profile of the anchor loop with respect to the first and second directions.
7 . The assembly of claim 1 , wherein the actuation member enters the interior passage at a first location of the anchor body and exits the interior passage at a second location of the anchor body.
8 . The assembly of claim 7 , wherein a passage length measured between the first and second locations along a central axis of the anchor body is in a range of about 8.0 mm to about 16.0 mm.
9 . The assembly of claim 8 , wherein the passage length is in a range of about 11.0 mm to about 14.0 mm.
10 . The assembly of claim 7 , wherein the anchor body comprises suture fibers braided together in a circular braided construct.
11 . The assembly of claim 7 , wherein the actuation member penetrates the circular braided construct at the first and second locations.
12 . The assembly of claim 7 , wherein, when the assembly is in the insertion configuration, the snake member enters and exits the interior passage at the first and second locations, respectively.
13 . The assembly of claim 7 , wherein the distal portion of the anchor body extends from the a proximal-most one of the first and second locations to a distal end of the anchor body, and when the assembly is in the insertion configuration, the distal portion of the anchor body has a length along the first direction that is in a range of about 28% to about 32% of the length of the anchor body.
14 . The assembly of claim 1 , wherein the snake member is constructed of suture.
15 . The assembly of claim 1 , wherein the free end region of the second snake tail defines a snake loop for receiving at least part of the free end region of the second actuation portion for coupling the free end region of the second snake tail with the free end region of the second actuation portion.
16 . The assembly of claim 15 , wherein the snake loop is defined by an eye splice of two portions of the second snake tail.