Polyaxial screw (original) (raw)

A polyaxial screw is used for connecting vertebrae to rods in spinal surgery, particularly spinal fusion procedures. It is a type of screw whose spherical head is enclosed in a housing, which allows the screw a range of motion along several different axes relative to the housing. The ball joint allows the surgeon some flexibility in placing the screws. The screws are typically placed into the pedicle of the vertebra.