Insertion instrument for a spinal fixation system

A medical instrument apparatus and method is provided to insert and release medical implants. This invention pertains generally to medical instruments and more specifically to spinal implant insertion instruments for spinal fixation systems. The insertion instrument may provide a positive locking and unlocking actuator, preferably in the form of a lever, which ensures that the pedicle screw and yoke assembly is either mechanically locked to the insertion instrument or unlocked to the insertion instrument. The positive locking and unlocking actuator of the insertion instrument eliminates guesswork for the surgeon because the surgeon can readily know if the pedicle screw and yoke assembly is attached to the insertion instrument or not. Superelastic components may also be included to shift components in a first direction and pull components under superelastic tension in a second direction for increased holding force.