US Patent RE49994 Spinal fusion implants and devices and methods for deploying such implants

Methods and apparatus are disclosed for distracting tissue. The devices and methods may include insertion of first and second elongated members into the space between two tissue layers, with an augmenting elongated member inserted therebetween to form a distraction device between the tissues to be distracted. The distraction device defines a generally annular configuration, with a locking member secured to one of the elongated members at a plurality of locations to maintain the distraction device in the generally annular configuration. The augmenting elongated member may be shorter than the first and second elongated members such that a window is defined between the proximal and distal ends of the augmenting elongated member when the distraction device and the first and second elongated members are in the generally annular configuration. Bone graft material or bone filler may be introduced into the interior of the distraction device through the window.