OBJECTIVE: compare the new self-tapping cervical spine locking plate (CSLP) screw with traditional self-tapping cortical screw used in anterior cervical locking plates in terms of insertion torque and pullout strength. METHODS: 15 traditional self-tapping cortical screws and 15 new self-drilling CSLP screws were inserted into 15 models of artificial bone (polyurethane) and 15 cervical vertebrae of sheep. The studied parameters were the insertional torque and pullout strength. The following groups were created, in agreement with the type of screw used: Group I, of self-tapping cortical screw; and Group II, with self-tapping CSLP screw. The pilot hole had 10.0 mm in depth and was made with a 2.5 mm (Group I) and 3.0 mm (Group II) drill. The insertional torque was measured and the pullout test was performed. RESULTS: the CSLP self-tapping screw presented a higher insertional torque and pullout strength compared to cortical self-tapping screws. CONCLUSION: the thread design of CSLP screw influenced the insertional torque and pullout resistance, and the evaluation of these parameter were superior to cortical self-tapping screw.
Spine; Bone screws; Biomechanics; Torque
