A kit for modular spine stabilization, comprising: an implantable modular spine stabilization system comprising: one or more flexible couplers for dynamic stabilization of a spinal segment of a patient's spine, each flexible coupler having a flexible main body at a first end and a stem (132a, 132b) extending therefrom and terminating at a second end; one or more rigid rods for rigid stabilization of a spinal segment of the patient's spine, each rigid rod having an elongated shaft (142a, 142b); and one or more bone fasteners for attaching the one or more flexible couplers or rigid rods to the patient's spine; and an instrument set for use with the implantable modular spine stabilization system, characterized in that the instrument set includes a bending instrument for bending a stem (132a, 132b) of one of the flexible couplers, the bending instrument comprising a base, a pivoting arm, and a pivoting rod holder, the pivoting arm having a pusher head extending from a lower surface of the pivoting arm, and the pivoting rod holder further having a portal for receiving the stem (132a, 132b) of the one or more flexible couplers, wherein the bending instrument has an open position and a fully closed position in which the stem (132a, 132b) of the flexible coupler is bent, the pivoting rod holder swiveling upward when the bending instrument is moved to the open position. an implantable modular spine stabilization system comprising: one or more flexible couplers for dynamic stabilization of a spinal segment of a patient's spine, each flexible coupler having a flexible main body at a first end and a stem (132a, 132b) extending therefrom and terminating at a second end; one or more rigid rods for rigid stabilization of a spinal segment of the patient's spine, each rigid rod having an elongated shaft (142a, 142b); and one or more bone fasteners for attaching the one or more flexible couplers or rigid rods to the patient's spine; and one or more flexible couplers for dynamic stabilization of a spinal segment of a patient's spine, each flexible coupler having a flexible main body at a first end and a stem (132a, 132b) extending therefrom and terminating at a second end; one or more rigid rods for rigid stabilization of a spinal segment of the patient's spine, each rigid rod having an elongated shaft (142a, 142b); and one or more bone fasteners for attaching the one or more flexible couplers or rigid rods to the patient's spine; and an instrument set for use with the implantable modular spine stabilization system, characterized in that the instrument set includes a bending instrument for bending a stem (132a, 132b) of one of the flexible couplers, the bending instrument comprising a base, a pivoting arm, and a pivoting rod holder, the pivoting arm having a pusher head extending from a lower surface of the pivoting arm, and the pivoting rod holder further having a portal for receiving the stem (132a, 132b) of the one or more flexible couplers, wherein the bending instrument has an open position and a fully closed position in which the stem (132a, 132b) of the flexible coupler is bent, the pivoting rod holder swiveling upward when the bending instrument is moved to the open position.