A surgical implant assembly and a method for securing a fixation rod, where the assembly is capable of being secured to a bone structure are disclosed. The assembly includes at least two rigid structures configured to be secured to the bone structure. The structures include a distal portion for receiving a portion of the fixation rod therebetween, a tab positioned at a distal point of the distal portion, a screw compression nut and a distal expansion member coupled to the screw compression nut that are driven down the rigid structures, and a rod compression nut and a proximal expansion member coupled to the rod compression nut that engage the rigid structures so that the fixation rod is disposed between the combination the screw compression nut and the distal expansion member and the combination of the rod compression nut and the proximal expansion member.
