title: Accuracy of Pedicle Screw Placement in Children 10 Years or Younger Using Navigation and Intraoperative CT.
abstract: METHODS
  A consecutive case series.
  
  
  OBJECTIVE
  To determine the revision rate for pedicle screws placed using intraoperative CT and image-guided navigation in children 10 years or younger.
  
  
  BACKGROUND
  Screws are frequently used for spinal instrumentation in young children, although this is only by physician-directed use. This is a multicenter retrospective study of patients aged 10 years or younger, who underwent spinal screw instrumentation with image-guided navigation. We hypothesized that intraoperative navigation would result in a high rate of accuracy for screw placement.
  
  
  METHODS
  Between 2007 and 2013, 130 pedicle and 7 lateral mass screws were placed in 16 consecutive patients undergoing a total of 17 surgeries at 2 institutions. Mean age at surgery was 6.9 years (range, 0.8-10.9 y). Screws were placed using an open technique with intraoperative CT (O-arm) and image-guided navigation (Stealth). Procedures included: growing spine device (3), hemivertebrae excision (4), posterior fusion (7), cervical fusion (2), and vertebral column resection (1). Congenital deformity was the most common diagnosis. Primary outcome measures were need for intraoperative screw revision or complication associated with screw placement.
  
  
  RESULTS
  Mean number of screws used per procedure was 8.1 (range, 2-17). Screws were placed from C1 to L5. Of the 137 screws, 3 required revision to shorter screws for an overall accuracy rate of 97.8%. In 1 case, a right T3 screw was revised due to anterior penetration. In another case, left-sided T1 and T2 pedicle screws were shortened 5 mm because they had penetrated the anterior aspect of their respective vertebral bodies. There were no screw-related complications.
  
  
  CONCLUSIONS
  In this series, image-guided navigation resulted in accurate placement of screws in patients aged 10 years or younger with no associated intraoperative complications. The navigated accuracy rate (97.8%) is significantly higher (P=0.01) than the reported 90.9% pedicle screw accuracy rate without navigation in the same age group by Baghdadi and colleagues. Intraoperative CT and image guidance were useful in our practice for placement of screws in skeletally immature patients.
authors.affiliation: *Department of Orthopedic Surgery, Mayo Clinic, Rochester†Department of Orthopaedic Surgery, University of Minnesota, Minneapolis‡Department of Neurosurgery, Mayo Clinic, Rochester, MN.
authors.forename: Tianyi D
authors.initials: TD
authors.lastname: Luo
authors.forename: David W
authors.initials: DW
authors.lastname: Polly
authors.forename: Charles G
authors.initials: CG
authors.lastname: Ledonio
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Wetjen
authors.forename: A Noelle
authors.initials: AN
authors.lastname: Larson
mesh_terms: D002648:Child; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods*; D065289:Pedicle Screws; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods*