Background Posterior instrumentation of the spine presents a challenge, especially in
conditions with low bone quality. Pedicle screw insertion with cortical bone trajectory is …

OBJECT Low bone mineral density in patients undergoing lumbar spinal surgery with
screws is an especially difficult challenge because poor bone quality can severely …

BACKGROUND CONTEXT: Achieving solid implant fixation to osteoporotic bone presents a
clinical challenge. New techniques and devices are being designed to increase screw–bone …

Purpose. To evaluate the insertion torque and pullout strength of pedicle screws with or
without repositioning. Methods. 20 fresh porcine lumbar vertebrae of similar size were used …

Objective: While much is known about the clinical outcomes of spinal fusion, questions
remain in our understanding of the biomechanical strength of lumbar pedicle screw fixation …

We tested the hypothesis that two pedicle screws placed in convergence offer more
resistance to axial pullout than do two pedicle screws placed in parallel. Eight fresh …

Background While convergent placement of pedicle screws in the axial plane is known to be
more advantageous biomechanically, surgeons intuitively aim toward a parallel placement …

Background context: Biomechanical studies show that bone-mineral density, pedicle
morphology, and screw thread area affect pedicle screw pullout failure. The current literature …

Background The biomechanical performance of the hooks and screws in spinal posterior
instrumentation is not well-characterized. Screw-bone interface failure at the uppermost and …

Purpose The cortical bone trajectory (CBT) is an alternative to the traditional pedicle screw
trajectory (TT) in posterior spinal instrumentation, enhancing screw contact with cortical …