POTENTIAL LARGE VESSEL INJURY DURING THORACOLUMBAR PEDICLE SCREW REMOVAL - A CASE-REPORT

Study Design. A case study of a previously unreported complication of unsuccessful broken pedicle screw removal in the thoracolumbar spine i s presented. Objectives. To emphasize an increased awareness of the po tential for large vessel injury during difficult broken pedicle screw removal in the thoracolumbar spine and to encourage the thorough evalu ation of indications for the removal of any broken distal fragment in a vertebral body. Summary of Background Data. Reported complications o f pedicle screw removal include the inability to remove the distal scr ew fragment, nerve root injury, and: dural sheath violation. Damage to anterior vascular structures,including the vena cava, iliac arterial and venous systems, and aorta, has not yet been reported in associatio n with difficult broken pedicle screw removal. Methods. An instrument designed to capture the distal end of a screw fragment through an inte rference fit resulted in inadvertent screw migration into the retroper itoneal space. Plain roentgenograms and computed tomography were used to document this complication, revealing the close proximity of the sc rew fragment to the aorta. Results. Expedient recognition of the anter iorly migrated screw fragment with its subsequent removal resulted in a satisfactory outcome. Conclusion. Great care must be taken during th e removal of broken pedicle screws to prevent injury to surrounding st ructures. Additionally, indications for the removal of distal screw fr agments must be carefully established. Instruments designed to capture the end of the distal screw fragment through an interference fit may allow anterior screw migration to occur, particularly in osteoporotic bone.