Objective
Intraoperative revision of initially loosened pedicle screws.
Indications
Intraoperatively loosened/stripped pedicle screws.
Contraindications
None.
Surgical technique
Removal of the loosened/stripped pedicle screw. Checking the screw channel and re-implantation using a different trajectory, a larger screw diameter or a cement-augmented pedicle screw.
Postoperative management
Early functional mobilization and initiation of osteoporosis therapy if indicated.
Results
A biomechanical study with human vertebral bodies was performed. Augmented and not augmented pedicle screws were tested until loosening using a fatigue testing setup. After loosening occurred a subsequent augmentation of the loosened, not augmented screw was performed, and it was tested using a fatigue test again. Both the initial (p = 0.009) and the augmentation after loosening (p = 0.001) showed a significant increase in failure load compared to the non-augmented pedicle screws. In our own patient collective from April 2016 to August 2018, 11 of 524 patients treated with pedicle screws showed intraoperative screw loosening. This was revised in 6 cases with a subsequent augmentation and in 5 cases with a larger screw diameter. In the postoperative control at 6 weeks, none of these screws showed loosening again.