A 2D threshold of the condylar-C1 interval to maximize identification of patients at high risk for atlantooccipital dislocation using computed tomography.
OBJECTIVE Measurement of the occipital condyle-C1 interval (CCI) is important in the evaluation of atlantooccipital dislocation (AOD) in pediatric trauma patients. The authors studied a large cohort of children with and without AOD to identify a 2D measurement threshold that maximizes the diagnostic yield of the CCI on cervical spine CT scans obtained in trauma patients. METHODS This retrospective, single-center study included all children who underwent CT of the cervical spine at Primary Children's Hospital from January 1, 2011, through December 31, 2014, for trauma evaluation. Bilateral CCI measurements in the coronal (3 measurements per side) and sagittal (4 measurements per side) planes were recorded. Using an iterative method, the authors determined optimal cutoffs for the maximal CCI in each plane in relation to AOD. The primary outcome was AOD requiring occipitocervical fusion. RESULTS A total of 597 pediatric patients underwent cervical spine CT for trauma evaluation: 578 patients without AOD and 19 patients with AOD requiring occipitocervical fusion. The authors found a statistically significant correlation between CCI and age (p < 0.001), with younger patients having higher CCIs. Using a 2D threshold requiring a sagittal CCI ≥ 2.5 mm and a coronal CCI ≥ 3.5 mm predicted AOD with a sensitivity of 95%, a specificity of 73%, positive predictive value of 10.3%, and negative predictive value of 99%. The accuracy of this 2D threshold was 84%. CONCLUSIONS In the present study population, age-dependent differences in the CCI were found on CT scans of the cervical spine in a large cohort of patients with and without AOD. A 2D CCI threshold as a screening method maximizes identification of patients at high risk for AOD while minimizing unnecessary imaging studies in children being evaluated for trauma.
Division of Pediatric Neurosurgery, Department of Neurosurgery, Primary Children's Hospital, University of Utah, Salt Lake City, Utah
Vijay
V
Ravindra
Department of Clinical Neurosciences, Division of Pediatric Neurosurgery, University of Calgary, Alberta, Canada
Jay
J
Riva-Cambrin
Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah
Kevin
K
Horn
Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah
Jason
J
Ginos
Division of Pediatric Neurosurgery, Department of Neurosurgery, Primary Children's Hospital, University of Utah, Salt Lake City, Utah
Russell
R
Brockmeyer
Division of Pediatric Neurosurgery, Department of Neurosurgery, Primary Children's Hospital, University of Utah, Salt Lake City, Utah
Jian
J
Guan
Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah
John
J
Rampton
Division of Pediatric Neurosurgery, Department of Neurosurgery, Primary Children's Hospital, University of Utah, Salt Lake City, Utah
Douglas
D
Brockmeyer
D000293:Adolescent; D001269:Atlanto-Occipital Joint / Q000000981:diagnostic imaging* / Q000293:injuries*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D004204:Joint Dislocations / Q000000981:diagnostic imaging*; D008297:Male; D012737:Sex Factors; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
AOD = atlantooccipital dislocation; CCI = occipital condyle–C1 interval; Oc = occiput; atlantooccipital dislocation; cervical spine; computed tomography; measurement; occipital condyle–C1 interval; pediatrics; trauma