A Biomechanical Comparison of Expansive Pedicle Screws for Severe Osteoporosis: The Effects of Screw Design and Cement Augmentation
Fig 5
Photographs showing various cemented screws after the pullout tests. Left to right: solid, 4-slit with 16-mm EEL, 4-slit with 22-mm EEL, 6-slit with 16-mm EEL, and 6-slit with 22-mm EEL.
A larger expansion range was observed for screws with 22-mm EELs compared with screws with 16-mm EELs and that cement infiltration into the open cell of the test block led to the formation of a cement/bone composite structure. Regardless of the number of slits (4 or 6), the cement/bone composite structure was distributed closer to the screw head for screws with a larger expansion range (22-mm EELs).