Prevention of dislodgement of Cotrel-Dubousset rods from tulip screws.

The authors report a case of posterior fusion of the lumbar spine using Cotrel-Dubousset instrumentation in which the rods dislodged from the tulip-headed pedicle screws postoperatively. They recommend that, to avoid this complication, particular care be taken to ensure the locking washers are inserted tightly without cross threading and that an adequate length of rod is left protruding beyond the screw.