Fig. 6From: Pedicle screw loosening: the value of radiological imagings and the identification of risk factors assessed by extraction torque during screw removal surgeryA typical case showing CT scan might be insensitive to detect screw loosening. a Anteroposterior X-ray showed radiolucent zone and double halo around the screw (black arrow) which indicate screw loosening. b Lateral X-ray showed that the same screw was pulled out (white arrow). c CT scan showed no gap around the same screwBack to article page