title: Comparison of Effective Dose of Radiation During Pedicle Screw Placement Using Intraoperative Computed Tomography Navigation Versus Fluoroscopy in Children With Spinal Deformities.
abstract: BACKGROUND
  We compared the effective dose of radiation associated with pedicle screw placement in posterior spinal fusion in children using intraoperative computed tomography (CT) navigation versus intraoperative fluoroscopy (C-arm).
  
  
  METHODS
  In this review of posterior spinal fusion patients, height, weight, local density function, dose area product, body region, number of views, and part of the body were used to calculate the effective dose to the patient in millisieverts (mSv) in 37 children in whom pedicle screw placement was aided by intraoperative CT versus 44 children in whom pedicle screw placement was aided by C-arm. Both groups had posterior spinal fusions during the same time period by 3 surgeons between November 2012 and August 2013. Calculation of the radiation dose was made by the following method: for the C-arm, and the fluoroscopic/digital acquisitions part of the CT examinations, we estimated the effective dose using the program PCXMC 2.0. For the cross-sectional imaging part of the CT examinations, we used the dose-length product from the radiation dose reports of the CT unit and published dose-length product to effective dose conversion factors. The overall effective dose for the CT group was the total of the cross-sectional imaging dose and the fluoroscopic/digital acquisition imaging dose. An unpaired T test was used to determine significant difference between the C-arm and CT navigation groups.
  
  
  RESULTS
  The average effective dose was 1.48±1.66 mSv for the CT patients and 0.34±0.36 mSv for the C-arm patients. These values for the 2 groups are significantly different (P=0.0012). Obese children had very high mSv values in the CT group.
  
  
  CONCLUSIONS
  Intraoperative CT for navigational instrumentation placement associated with spinal fusion in children results in significantly more radiation to the child than C-arm. Families need to be counseled about radiation exposure associated with intraoperative CT, especially in obese children. Intraoperative CT use should be tailored to placing instrumentation where the benefit is the highest.
  
  
  METHODS
  Level II.
authors.affiliation: Departments of *Orthopedic Surgery †Radiology, University of Michigan, Ann Arbor, MI.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Dabaghi Richerand
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Christodoulou
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Caird
authors.forename: Nahbee
authors.initials: N
authors.lastname: Jong
authors.forename: Frances A
authors.initials: FA
authors.lastname: Farley
mesh_terms: D001863:Bone Screws; D002648:Child; D015331:Cohort Studies; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D065289:Pedicle Screws; D011829:Radiation Dosage; D000069079:Radiation Exposure; D012600:Scoliosis / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*