The effect of repetitive pilot-hole use on the insertion torque and pullout strength of vertebral system screws - Defino, Helton Luiz Aparecido; Rosa, Rodrigo César; Silva, Patrícia; Shimano, Antonio Carlos; Volpon, Jose Batista; Paula, Francisco Jose Albuquerque de; Schleicher, Philipp; Schnake, Klaus; Kandziora, Frank (Spine, 2009)