title: The effect of rod diameter on correction of adolescent idiopathic scoliosis at two years follow-up.
abstract: METHODS
  The review of multicenter national pediatric scoliosis database.
  
  
  OBJECTIVE
  The purpose of this study was to compare the radiographic outcomes of patients who underwent scoliosis surgery utilizing different rod diameter constructs by the posterior approach.
  
  
  BACKGROUND
  Little attention has specifically been focused on the effect of rod diameter on correction of spinal deformity after posterior spinal instrumentation and fusion in children with adolescent idiopathic scoliosis (AIS).
  
  
  METHODS
  The review of national database comprised of 1125 patients, of which 352 patients had a minimum follow-up of 2 years. Of these, 163 patients received 5.5 mm and 189 patients received 6.35 mm diameter rods for posterior spinal instrumentation.
  
  
  RESULTS
  The 6.35 mm rods were used more often for patients who were male, taller, heavier, with larger coronal curves, and more flexible curves. Larger diameter rods were also more likely to be stainless steel, implanted with an increased number of implants per level, and an increased number of pedicle screws used on the concavity of the curve. Univariate analysis of coronal curve showed a significant difference between 5.5 and 6.35 mm rods in correction (67.0% vs. 57.3%) at 2 years. Multivariate analysis revealed that the most significant factors affecting coronal curve correction at 2 years were rod diameter, the patient's preoperative coronal major curve and flexibility, and the implant density. In the sagittal plane, preoperative sagittal curve and rod diameter are the predictors of sagittal correction at 2 years.
  
  
  CONCLUSIONS
  The study did not support our hypothesis that larger rods would be associated with a greater correction of frontal and sagittal plane in patients with AIS. In addition to rod diameter, implant density and the inherent flexibility and deformity of the patient were found to be influential factors contributing for the correction and maintenance of coronal and sagittal curves in AIS.
authors.affiliation: *Sinai Hospital of Baltimore, Baltimore, MD †Division of Pediatric Orthopaedic Surgery, Department of Orthopaedic Surgery ‡Department of Orthopaedic Surgery, Columbia University §New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, NY.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Prince
authors.forename: Hiroko
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Charles M
authors.initials: CM
authors.lastname: Chan
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Gomez
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Hyman
authors.forename: David P
authors.initials: DP
authors.lastname: Roye
authors.forename: Michael G
authors.initials: MG
authors.lastname: Vitale
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002648:Child; D015331:Cohort Studies; D016208:Databases, Factual; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D008297:Male; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods; D011183:Postoperative Complications / Q000453:epidemiology / Q000503:physiopathology; D011859:Radiography; D020127:Recovery of Function; D012044:Regression Analysis; D012189:Retrospective Studies; D018570:Risk Assessment; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult