Multi-axial expandable pedicle screw and an expansion method thereof

摘要

A multi-axial expandable pedicle screw includes a hollow screw having a spherical shaped end for connecting with an adapting piece in the form of a universal joint structure. The hollow screw further includes a tip shaped end, and a bore formed inside the hollow structure having a taper shaped tip. Expansion gaps are formed in the hollow screw to uniformly set up two, three, four or more anterior fins on the hollow screw extending upward along its axial direction, from its tip to the bore. The hollow screw is configured to receive an inner needle disposed in the bore. This pedicle screw is easy to operate and provides a high degree of control in screw expansion with increased stability and reliability. At the same time, this pedicle screw reduces the occurrence of screw loosening, and screw pull-out events, and also reduces failure rates of spinal surgeries.