Related Experiment Video
Updated: Apr 11, 2026
07:32
Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
2.1K
Posterior odontoid process angulation in pediatric Chiari I malformation: an MRI morphometric external validation
Travis R Ladner1, Michael C Dewan1, Matthew A Day2
1Department of 1 Neurological Surgery and.
Journal of Neurosurgery. Pediatrics
|June 9, 2015
Summary
Posterior angulation of the odontoid process is common in children with Chiari I malformation (CM-I). This bony anomaly correlates with increased tonsillar ectopia, suggesting a link between craniocervical junction development and CM-I severity.
Area of Science:
- Neurosurgery
- Pediatric Neurology
- Radiology
Background:
- Craniocervical junction osseous anomalies are implicated in the hindbrain herniation seen in Chiari I malformation (CM-I).
- Prior research indicated a higher prevalence of posterior odontoid process angulation in pediatric CM-I patients compared to controls.
Purpose of the Study:
- To externally validate previous findings on odontoid process angulation in a new pediatric CM-I cohort.
- To analyze variations in craniometric parameters with age, sex, and clinical symptoms.
- To develop a model correlating these measurements with tonsillar ectopia in CM-I.
Main Methods:
- Retrospective review of 78 pediatric patients with CM-I who underwent posterior fossa decompression.
- Neuroradiological assessment of preoperative MRI scans for measurements including McRae line, obex displacement, and odontoid process parameters (height, retroflexion, retroversion).
- Statistical analysis (regression, ANOVA, Fisher's exact test) to evaluate relationships between craniometric variables and demographic/clinical factors.
Main Results:
- Posterior odontoid angulation was observed in 81% of the study population, consistent with previous reports.
- Increasing age correlated with greater odontoid height, increased posterior inclination of the odontoid process, and a longer perpendicular distance to the basion-C2 line (pB-C2 line).
- Increased tonsillar ectopia was significantly associated with a larger foramen magnum, greater obex displacement, and more pronounced odontoid retroflexion.
Conclusions:
- Anomalous bony development at the craniocervical junction is a consistent finding in pediatric CM-I.
- The study confirms a high prevalence of posterior odontoid angulation and demonstrates its association with increased tonsillar ectopia.
- Age-related changes in odontoid morphology were observed, with increased posterior inclination linked to greater CM-I severity.
