Retrieval of broken pedicle screws by "friction" technique. Technical note.

The authors describe a simple and fast technique for removal of deeply situated broken pedicle screw fragments. The screw fragments are removed using a fine-serrated, conically cored bit with a light rough inner surface that is mounted on a common slow-speed drill capable of rotating clockwise and counterclockwise. The cored head of the bit is pressed and engaged on the cut surface of the broken screw, and the drill is made to turn in counterclockwise rotation; this, by means of friction, causes the two surfaces to interlock, and consequently the broken screw fragment backs out. This technique was used to retrieve both broken titanium and stainless steel screws, and satisfying results were obtained. There were no complications associated with the application of the technique, and the pedicle as well as the screw hole were always preserved, offering, in the event that the vertebral instability continued, the possibility of applying a new screw of slightly larger diameter at the same screw hole. This technical application offers the opportunity of removing deeply situated screw fragments by using a simple technique while maintaining the vertebral pedicle and screw-hole integrity.