The Relationship between Age, Gender, and the Craniocervical Junction

Introduction: Anterior surgical approaches to craniocervical junction continue to evolve. The introduction of endoscopy has allowed for less invasive and alternative approaches, such as endoscopic odontoid approaches and high-cervical approaches. The optimal surgical corridors for anterior cervicomedullary junction pathology are not well defined relative to the C1–2 anatomy and typically depend on the location of the hard palate. Furthermore, it is unknown if relative anatomy changes with aging. We hypothesize that the atlantodental complex changes its relationship to the hard palate with aging.

Methods: Billing records were reviewed from 2008 to 2014 for the patients who obtained a cervical or maxillofacial CT as part of a trauma evaluation for orbital and/or skull fractures. The initial search identified 606 patients. Patients who had a CT scan that allowed adequate visualization of the hard palate and opisthion and the upper cervical spine (C1 and C2) were included. Pediatric patients were excluded (younger than 18 years), as were patients with cervical spine fractures, or known history of rheumatoid. The distance from the inferior arch of C1 and midpoint of the inferior endplate of C2 from McGregor line was measured on midsagittal CT scans. Patients were grouped by decile of age and by young (range, 18–40 years), middle aged (range, 40–60 years), older aged adults (60+ years), and by gender. A one-way ANOVA was performed with each respective grouping. Multivariate regression was performed with gender and age stratification.

Results: Ultimately, 417 patients (29% females) were included. The mean age was 51.6 ± 21.6 years. Young adults comprised 34% of the cohort, compared with 28 and 38% for middle- and older-aged adults. Significant differences were found when comparing distances from C1 and C2 relative to McGregror line when comparing decile of age (p < 0.0001), and middle age compared with older adults (p < 0.01). A mean difference of 2 mm of settling occurred between transitioning from older than 60 years to middle-aged adults at C1 and C2 (14.5 vs. 12.8 mm and 38.5 and 33.3 mm). When comparing C1 and C2 distances between deciles of age, the mean difference increased by 3 mm when comparing patients in their second decade of life compared with patients in their fifth decade, and then decreased by 4 mm when comparing patients in their fifth decade to patients in their tenth decade. Distances also significantly varied with gender at C1 (11.8 mm for females vs. 14.4 mm for males) and C2 (33.6 mm for females vs. 38.2 mm for males). Multivariate analysis showed that both age and gender independently correlated with the C1 and C2 distances from McGregor line.

Conclusion: The craniocervical junction settles with age, particularly past the sixth decade of life. Distances also vary significantly with respect to gender.