Rodrigo César Rosa1, Patrícia Silva1, Maurício José Falcai1, Antônio Carlos Shimano2, Helton Luiz Aparecido Defino3. 1. Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirao Preto School of Medicine, University of Sao Paulo (USP), Ribeirao Preto, SP, Brazil. 2. Associate Professor in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirao Preto School of Medicine, University of Sao Paulo (USP), Ribeirao Preto, SP, Brazil. 3. Titular Professor of the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirao Preto School of Medicine, University of Sao Paulo (USP), Ribeirao Preto, SP, Brazil.
Abstract
OBJECTIVE: To evaluate the influence of pilot hole tapping on pullout resistance and insertion torque of pedicle screws with a conical core. METHODS: Mechanical tests using a universal testing machine were performed on pedicle screws with a conical core that were inserted into pedicles in the fifth lumbar vertebra of calves. The insertion torque was measured using a torque meter with a capacity of 10 Nm, which was considered to be the highest torque value. The pilot holes were prepared using a probe of external diameter 3.8 mm and tapping of the same dimensions and thread characteristics as the screw. RESULTS: Decreased insertion torque and pullout resistance were observed in the group with prior tapping of the pilot hole. CONCLUSIONS: Pilot hole tapping reduced the insertion torque and pullout resistance of pedicle screws with a conical core that had been inserted into the pedicle of the fifth lumbar vertebra of calves.
OBJECTIVE: To evaluate the influence of pilot hole tapping on pullout resistance and insertion torque of pedicle screws with a conical core. METHODS: Mechanical tests using a universal testing machine were performed on pedicle screws with a conical core that were inserted into pedicles in the fifth lumbar vertebra of calves. The insertion torque was measured using a torque meter with a capacity of 10 Nm, which was considered to be the highest torque value. The pilot holes were prepared using a probe of external diameter 3.8 mm and tapping of the same dimensions and thread characteristics as the screw. RESULTS: Decreased insertion torque and pullout resistance were observed in the group with prior tapping of the pilot hole. CONCLUSIONS: Pilot hole tapping reduced the insertion torque and pullout resistance of pedicle screws with a conical core that had been inserted into the pedicle of the fifth lumbar vertebra of calves.
Authors: M Pfeiffer; L G Gilbertson; V K Goel; P Griss; J C Keller; T C Ryken; H E Hoffman Journal: Spine (Phila Pa 1976) Date: 1996-05-01 Impact factor: 3.468