INFLUENCE OF DIAMETER AND GEOMETRY IN THE TAPPING OF THE PILOT HOLE IN PEDICLE SCREWS

• Autor(a) principal: Defino,Helton Luiz Aparecido
• Data de Publicação: 2019
• Outros Autores: Miranda,Raffaello de Freitas, Pinheiro,Romulo Pedroza, Shimano,Antonio Carlos
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Coluna/Columna
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1808-18512019000100051
• topic: Spine; Bone screws; Spinal fusion

ABSTRACT Objective: To evaluate the insertion torque and the pulling force of each screw with different diameters and tap. Methods: Polyurethane blocks with a pilot hole of 2.7 mm were used in the study. An experimental group with 5 blocks was formed, the insertion torque was evaluated with a torque meter, and the pullout strength of each Globus screw of 5.5 mm and 6.5 mm was assessed. Results: The comparison of the insertion torque on the 5.5 mm screws with pilot hole without tapping and with a smaller diameter than that of the screw (4.5 mm) and a different thread, and with the tapping with the same diameter as that of the screw (5.5 mm) and equal or different thread presented a statistical difference with a higher value of the insertion torque in the group in which the tapping was not performed. As for the pulling force of the 5.5 mm screw, the non-tapping of the pilot hole resulted in statistical difference with the same diameter of the screw (5.5 mm) and with a different thread of the screw. The pullout force on the 6.5 mm screw was higher in the group where the pilot hole was not tapped according to the non-parametric Kruskal-Wallis test, with significance level of p <0.05 in the comparison of the groups. Conclusions: Pilot hole tapping reduced insertion torque and pullout resistance of the pedicle screw influencing the fixation with tapping with the same screw diameter and different thread design.