A tissue retractor system (100) includes first (240) and second (260) arms extending from a support assembly (210), and third (340) and fourth (360) arms extending from a support mechanism (310). Each arm includes a proximal span (242,262), a distal span (246,266), and a blade support (244,264) between the proximal span and distal span. The retractor system features retractor units (200,300) that can be used independently or in a nested arrangement. The system also includes instruments for inserting a spiral rod. A method for implanting a spinal rod through an incision includes the steps of inserting the spinal rod through a dividable tube, turning the rod subcutaneously toward a rod receiving anchor and advancing the rod subcutaneously toward the rod receiving anchor.
