title: Application of Normative Occipital Condyle-C1 Interval Measurements to Detect Atlanto-Occipital Injury in Children.
abstract: Prior studies have found that widening or asymmetry of the occipital condyle-C1 interval on CT is a sensitive and specific marker for atlanto-occipital dislocation. Previously reported abnormal occipital condyle-C1 interval values are not age-specific, possibly leading to false-positive findings in younger children, in whom this joint space is normally larger than that in adults. This study assesses the utility of applying age-specific normative occipital condyle-C1 interval ranges to documented cases of atlanto-occipital injury compared with previously reported abnormal cutoff values.
  
  
  
  Retrospective review of CT and MR imaging of 14 subjects with atlanto-occipital injury was performed, and occipital condyle-C1 interval measurements were made for each subject. Sensitivities and specificities of proposed occipital condyle-C1 interval cutoffs of 2 and 3 SDs above the mean and previously published occipital condyle-C1 interval cutoffs for atlanto-occipital injury were then calculated on the basis of occipital condyle-C1 interval measurements for each subject.
  
  
  
  An occipital condyle-C1 interval 2 SDs above the age-specific mean has a sensitivity of 50% and specificity of 89%-100%, depending on the age group. An occipital condyle-C1 interval 3 SDs above the age-specific mean has a sensitivity of 50% and a specificity of 95%-100%. A 4.0-mm occipital condyle-C1 interval has a sensitivity of 36% and a specificity of 100% in all age groups. A 2.5-mm occipital condyle-C1 interval has a sensitivity of 93% and a specificity of 18%-100%.
  
  
  
  Occipital condyle-C1 interval widening cutoffs used to establish atlanto-occipital injury lack both sensitivity and specificity in children and young teenagers. MR imaging is necessary to establish a diagnosis of atlanto-occipital injury in children and young teenagers when the appropriate mechanism of injury is present.
authors.affiliation: From the Departments of Radiology (B.C., L.L.L., J.L.L.).
authors.forename: B
authors.identifier: 0000-0003-1242-3871
authors.initials: B
authors.lastname: Corcoran
authors.affiliation: From the Departments of Radiology (B.C., L.L.L., J.L.L.) luke.linscott@cchmc.org.
authors.forename: L L
authors.identifier: 0000-0001-6074-0789
authors.initials: LL
authors.lastname: Linscott
authors.affiliation: From the Departments of Radiology (B.C., L.L.L., J.L.L.).
authors.forename: J L
authors.identifier: 0000-0002-6574-9982
authors.initials: JL
authors.lastname: Leach
authors.affiliation: Neurosurgery (S.V.), Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, Ohio.
authors.forename: S
authors.identifier: 0000-0003-1419-5673
authors.initials: S
authors.lastname: Vadivelu
mesh_terms: D000293:Adolescent; D000328:Adult; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000293:injuries; D001269:Atlanto-Occipital Joint / Q000000981:diagnostic imaging* / Q000293:injuries*; D002648:Child; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed