title: Comparative radiation exposure using standard fluoroscopy versus cone-beam computed tomography for posterior instrumented fusion in adolescent idiopathic scoliosis.
abstract: METHODS
  Retrospective cohort.
  
  
  OBJECTIVE
  The objective of this study was to define the intraoperative radiation exposure during freehand surgical technique with fluoroscopic assistance for placement and confirmation of posterior instrumentation in patients with adolescent idiopathic scoliosis and compare data with published values using intraoperative cone-beam computed tomography (CBCT) for similar cases.
  
  
  BACKGROUND
  The treatment of idiopathic-like scoliosis used freehand placement of posterior instrumentation with fluoroscopic confirmation. Computer-assisted navigation systems coupled with intraoperative CBCT have been introduced to aid in accurate placement of instrumentation. Multiple studies report the improved accuracy of instrumentation using CBCT; however, there is a paucity of information regarding the radiation exposure when using CBCT in comparison with fluoroscopically assisted freehand technique.
  
  
  METHODS
  Forty-three idiopathic-like scoliosis operations performed by 4 spine surgeons at an academic institution were retrospectively reviewed. Radiation exposure was recorded intraoperatively for each case. Effective dose was determined using published effective dose to dose-length product conversion factors. Values were compared with previous studies reporting radiation exposure for similar cases using CBCT for intraoperative navigation and confirmation of instrumentation placement.
  
  
  RESULTS
  Calculated average effective dose using fluoroscopically assisted pedicle screw placement was 0.189 mSv (range, 0.00029-0.953 mSv; SD = 0.16711) per case. Average radiation exposure time was 26 seconds (SD = 18 s) per case, with an average of 11 vertebral levels fused. The literature reports effective dose for CBCT ranging from 7.29 to 9.72 mSv per case for intraoperative navigation and 14.58 to 19.44 mSv per case for both intraoperative navigation and confirmation of screw placement with CBCT.
  
  
  CONCLUSIONS
  We have demonstrated that the use of standard fluoroscopy results in markedly lower radiation exposure during a standard posterior instrumented fusion for idiopathic-like scoliosis than by the use of CBCT; this conclusion is limited by the retrospective nature of the study and lack of a control group.
  
  
  METHODS
  4.
authors.affiliation: *Department of Orthopedics and Sports Medicine, University of Washington, Seattle, WA; and †Department of Orthopedics and Sports Medicine, Seattle Children's Hospital, Seattle, WA.
authors.forename: Courtney
authors.initials: C
authors.lastname: OʼDonnell
authors.forename: Andrew
authors.initials: A
authors.lastname: Maertens
authors.forename: Viviana
authors.initials: V
authors.lastname: Bompadre
authors.forename: Theodore A
authors.initials: TA
authors.lastname: Wagner
authors.forename: Walter
authors.initials: W
authors.lastname: Krengel
mesh_terms: D000293:Adolescent; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D008297:Male; D011829:Radiation Dosage; D012189:Retrospective Studies; D012600:Scoliosis / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*