A device for containing a graft material includes an outer member formed via an outer mesh sheet biased toward a coiled configuration in which the outer mesh sheet is coiled about a longitudinal axis thereof so that, when the outer member is positioned about separated portions of a target bone in an operative position, the outer member reverts to the coiled configuration and contracts about and engages the separated portions. The device also includes an inner member formed via an inner mesh sheet coiled about a longitudinal axis thereof. The inner member is movable between a first biased coiled configuration and a second coiled configuration. A diameter of the inner member in the first coiled configuration is larger than a diameter of the inner member in the second coiled configuration.