title: Switching to a Pediatric Dose O-Arm Protocol in Spine Surgery Significantly Reduced Patient Radiation Exposure.
abstract: BACKGROUND
  Intraoperative computed tomography and image-guided navigation improve the accuracy of screw placement. Radiation exposure to the patient remains a primary drawback. The objective of the present study was to compare the total intraoperative radiation dose and assess the resultant image quality for O-arm-assisted pedicle screw insertion, among 3 protocols: default (manufacturer recommended), institutional (reduced dose utilized in our institution), and pediatric (new protocol with lowest dose).
  
  
  METHODS
  Thirty-seven consecutive patients under the age of 18 years underwent posterior instrumentation of the spine and underwent an intraoperative O-arm scan. Techniques (kV and mAs) for default and institutional dose settings were manually adjusted based on spinal level and body weight. Pediatric dose techniques were 80 kV/80 mAs with no adjustment for level or weight. The number of scans repeated because of inadequate imaging was assessed, and the mean estimated effective dose between the 3 protocols was compared.
  
  
  RESULTS
  Sixty-eight scans were performed in 37 consecutive patients with mean age of 14 years and mean weight of 55 kg. For reference, the effective radiation dose of a chest x-ray is approximately 0.10 mSv. Use of the default protocol resulted in higher mean effective dose per scan of 4.65 mSv, whereas institutional protocol resulted in 2.37 mSv. The pediatric protocol reduced the mean dose to 0.65 mSv. The total effective dose per surgery was: 1.17 mSv (pediatric), 3.83 mSv (institutional), and 12.79 mSv (default) (P<0.0001 each). All scans lead to satisfactory image quality except in 1 patient >100 kg with stainless steel implants. There were no neurological or other implant-related complications. The pediatric protocol resulted in satisfactory image quality with the lowest total radiation dose, only 1/10 of that of the default protocol.
  
  
  CONCLUSIONS
  We successfully switched to a pediatric low-dose O-arm protocol in clinical practice, reducing the dose to <1/4 of the mean annual natural background radiation. This may allow use of intraoperative computed tomography and navigation for pedicle screw placement without excessive radiation exposure to young patients.
  
  
  METHODS
  Level III-retrospective comparative study.
authors: Departments of *Orthopaedic Surgery §Radiology, Mayo Clinic, Rochester, MN †Department of Surgery, School of Medicine, National Yang-Ming University, Taipei, Taiwan ‡Department of Orthopedic Surgery, Texas Scottish Rite Hospital for Children, Dallas, TX.
authors: Alvin W
authors: AW
authors: Su
authors: T David
authors: TD
authors: Luo
authors: Amy L
authors: AL
authors: McIntosh
authors: Beth A
authors: BA
authors: Schueler
authors: Jennifer A
authors: JA
authors: Winkler
authors: Anthony A
authors: AA
authors: Stans
authors: A Noelle
authors: AN
authors: Larson
mesh_terms: D000293:Adolescent; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000379:methods; D065289:Pedicle Screws; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000592:standards; D012189:Retrospective Studies; D020379:Risk Adjustment; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000009:adverse effects / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods