An assembly for treating a spinal disorder includes a sleeve having a socket end, a tool-receiving end and a wall extending between the socket end and tool-receiving end. The socket end has a socket opening for receiving a bone fixation screw cap and a pair of opposing notches for accommodating an elongated fixation member. A sleeve wall forms a bore extending axially between the tool-receiving end and the socket end of the sleeve. A method for repairing a spinal disorder includes the step of inserting a polyaxial screw into a vertebral bone, where the polyaxial screw has a screw cap. An elongated fixation member is inserted into the screw cap, followed by a fastener which is inserted into the screw cap in proximity to the fixation member. An adjustment device is connected to the screw cap to adjust the position of the polyaxial screw and vertebral bone.