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Normal Development and Measurements of the Occipital Condyle-C1 Interval in Children and Young Adults
P Smith1, L L Linscott2, S Vadivelu3
1From the Departments of Radiology (P.S., L.L.L., J.L.L.).
Insights
The occipital condyle-C1 interval changes significantly with age in children, impacting atlanto-occipital dislocation detection. Normative data is crucial for accurate diagnosis across different age groups.
Area of Science:
- Pediatric radiology
- Orthopedic imaging
- Cervical spine anatomy
Background:
- Atlanto-occipital dislocation detection relies on the occipital condyle-C1 interval.
- Previous studies show significant variation in normal condyle-C1 interval measurements in children.
- This study investigates age-related changes in condyle-C1 interval morphology.
Purpose of the Study:
- To determine if condyle-C1 interval morphology and joint measurements change with age.
- To establish age-specific normative data for the condyle-C1 interval.
- To assess the prevalence of medial occipital condyle notches.
Main Methods:
- Retrospective review of CT scans of the upper cervical spine in 124 subjects (2 days to 22 years).
- Measurement of the condyle-C1 interval on sagittal and coronal images.
- Analysis of measurements across 7 age groups.
Main Results:
- The condyle-C1 interval shows substantial age-related variation.
- Coronal measurements are larger and more variable than sagittal measurements.
- Medial occipital condyle notches are common in children aged 1-12 years.
Conclusions:
- The condyle-C1 interval increases in early childhood, peaks between 2-4 years, and then decreases.
- A single threshold for atlanto-occipital dissociation may not be universally applicable.
- Clinical utility requires applying normative data to trauma cases.
Background And Purpose:
Widening of the occipital condyle-C1 interval is the most specific and sensitive means of detecting atlanto-occipital dislocation. Recent studies attempting to define normal measurements of the condyle-C1 interval in children have varied substantially. This study was performed to test the null hypothesis that condyle-C1 interval morphology and joint measurements do not change as a function of age.
Materials And Methods:
Imaging review of subjects undergoing CT of the upper cervical spine for reasons unrelated to trauma or developmental abnormality was performed. Four equidistant measurements were obtained for each bilateral condyle-C1 interval on sagittal and coronal images. The cohort was divided into 7 age groups to calculate the mean, SD, and 95% CIs for the average condyle-C1 interval in both planes. The prevalence of a medial occipital condyle notch was calculated.
Results:
Two hundred forty-eight joints were measured in 124 subjects with an age range of 2 days to 22 years. The condyle-C1 interval varies substantially by age. Average coronal measurements are larger and more variable than sagittal measurements. The medial occipital condyle notch is most prevalent from 1 to 12 years and is uncommon in older adolescents and young adults.
Conclusions:
The condyle-C1 interval increases during the first several years of life, is largest in the 2- to 4-year age range, and then decreases through late childhood and adolescence. A single threshold value to detect atlanto-occipital dissociation may not be sensitive and specific for all age groups. Application of this normative data to documented cases of atlanto-occipital injury is needed to determine clinical utility.
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