Abstract: Embodiments of a surgical instrument disclosed herein can include mechanisms for reduction and distraction as well as compression. Some embodiments of the surgical instrument may comprise a reducer knob having a first passage through which a first shaft of a driver is acceptable, a connecting element coupled to the reducer knob and having a second passage through which the first shaft of the driver is acceptable, a compressor handle coupled to the connecting element at a first end and having a through hole, and a common handle coupled to the compressor handle via the through hole and pivots between the reducer knob and the compressor handle. With embodiments of a surgical instrument disclosed herein, surgical personnel can distract and hold vertebrae in a distracted state and perform a reduction without having to switch or add instruments. Some embodiments disclosed herein can be particularly useful for reducing spondylolisthesis during posterior fixation.

Abstract: A poly-axial bone fastener assembly having a collar and a bone fastener can be coaxially locked to prevent poly-axial movements of the collar relative to the bone fastener while permitting the collar to rotate about an axis of the bone fastener, thereby combining the functions and advantages of a poly-axial bone screw and a fixed angle bone screw. Some embodiments of a coaxial locking mechanism may include a c-clip with a locking pin, a c-clip with hooks, a split ring with square corners, a pin that spins inside the collar, pins that travel about a neck of the bone fastener, a coaxially locking top that screws into the collar over a head of the bone fastener, and a top nut that threads onto the head of the bone fastener inside the collar to trap a flange of the collar between a shoulder of the bone fastener and the top nut.

Abstract: A poly-axial bone fastener assembly having a collar and a bone fastener can be coaxially locked to prevent poly-axial movements of the collar relative to the bone fastener while permitting the collar to rotate about an axis of the bone fastener, thereby combining the functions and advantages of a poly-axial bone screw and a fixed angle bone screw. Some embodiments of a coaxial locking mechanism may include a c-clip with a locking pin, a c-clip with hooks, a split ring with square corners, a pin that spins inside the collar, pins that travel about a neck of the bone fastener, a coaxially locking top that screws into the collar over a head of the bone fastener, and a top nut that threads onto the head of the bone fastener inside the collar to trap a flange of the collar between a shoulder of the bone fastener and the top nut.

Abstract: Embodiments of a surgical instrument disclosed herein can include mechanisms for reduction and distraction as well as compression. Some embodiments of the surgical instrument may comprise a reducer knob having a first passage through which a first shaft of a driver is acceptable, a connecting element coupled to the reducer knob and having a second passage through which the first shaft of the driver is acceptable, a compressor handle coupled to the connecting element at a first end and having a through hole, and a common handle coupled to the compressor handle via the through hole and pivots between the reducer knob and the compressor handle. With embodiments of a surgical instrument disclosed herein, surgical personnel can distract and hold vertebrae in a distracted state and perform a reduction without having to switch or add instruments. Some embodiments disclosed herein can be particularly useful for reducing spondylolisthesis during posterior fixation.