Pedicle screws are designed to provide polyaxial coupling to pedicles of a vertebra. Intermediate pieces (80) are attached to the pedicles screws (140, 142, 148) and receive extender shafts (180A, 182A, 188A). Extenders (180A, 182A, 188A) are inserted in the intermediate pieces (80). The extenders (180A, 182A, 188A) project the anatomic points located in the cages (152) outside the patient's body to facilitate proper contouring of a rod. An alignment linkage (310) is used to ensure that the extenders (180A, 182A, 188A) are parallel to each other. The alignment linkage (310) includes a linkage frame (312), an articulating linkage (314) and a locking member (316). The articulating linkage (314) has all rotational degrees of freedom and thereby adapts to any varying trajectories of the extenders and distance between the extenders. The alignment linkage (310) includes a locking member (316) with a pop-up indicator. The pop-up indicator notifies the users when the locking member (316) is tightened with two of the extenders in non-parallel configuration.