A SCREW-ROD INSTRUMENT SPECIALLY USED FOR POSTERIOR ATLANTOAXIAL VERTEBRAE FIXATION

摘要

The invention discloses a screw-rod instrument specially used for posterior atlantoaxial vertebrae fixation, comprising two pulling-screws (2), two supporting-screws (1), two variable cross section fixing rods (3), two lock nuts (4) and a bracing beam (5). Each of the variable cross section fixing rods (3) is configured to connect a supporting-screw (1) and a pulling-screw (2), the bracing beam (5) is configured to connect both of the variable cross section fixing rods (3); wherein each of the supporting-screws (1) comprises a first tail (11) and a first head (12), and each of the pulling-screws (2) comprises a second tail (21) and a second head (22); both the first tail (11) and the second tail (21) are provided with nail grooves, with U-shaped grooves on the sides; wherein each of the nail grooves is provided with internal thread inside, and the lock nut (4) is connected with the nail groove; each of the variable cross section fixing rods (3) passes through the U-shaped grooves and is fastened by the lock nut (4); the bottoms of the nail grooves of the supporting-screws (1) are 2-6 mm higher than the bottoms of the nail grooves of the pulling-screws (2). The aforementioned screw-rod instrument not only increases the safety and convenience of a surgery, but also improves the function of spondylolisthesis reduction of the screw-rod system through raising the bottoms of the nail grooves 2-6 mm higher.