title: Potential large vessel injury during thoracolumbar pedicle screw removal. A case report.
abstract: METHODS
  A case study of a previously unreported complication of unsuccessful broken pedicle screw removal in the thoracolumbar spine is presented.
  
  
  OBJECTIVE
  To emphasize an increased awareness of the potential for large vessel injury during difficult broken pedicle screw removal in the thoracolumbar spine and to encourage the thorough evaluation of indications for the removal of any broken distal fragment in a vertebral body.
  
  
  BACKGROUND
  Reported complications of pedicle screw removal include the inability to remove the distal screw 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 association with difficult broken pedicle screw removal.
  
  
  METHODS
  An instrument designed to capture the distal end of a screw fragment through an interference fit resulted in inadvertent screw migration into the retroperitoneal space. Plain roentgenograms and computed tomography were used to document this complication, revealing the close proximity of the screw fragment to the aorta.
  
  
  RESULTS
  Expedient recognition of the anteriorly migrated screw fragment with its subsequent removal resulted in a satisfactory outcome.
  
  
  CONCLUSIONS
  Great care must be taken during the removal of broken pedicle screws to prevent injury to surrounding structures. Additionally, indications for the removal of distal screw fragments 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.
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Vanichkachorn
authors.forename: A R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: M J
authors.initials: MJ
authors.lastname: Cohen
authors.forename: J M
authors.initials: JM
authors.lastname: Cotler
mesh_terms: D000328:Adult; D001011:Aorta / Q000293:injuries*; D001863:Bone Screws / Q000009:adverse effects*; D004868:Equipment Failure; D005547:Foreign Bodies / Q000601:surgery*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D016103:Spinal Fractures / Q000601:surgery; D013123:Spinal Fusion; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed