The association of ossification of nuchal ligament with craniocervical posture and craniofacial morphology: a cephalometric study.

OBJECTIVES

To investigate the relationship between ossification of nuchal ligament (ONL) with both craniocervical posture and craniofacial morphology.

METHODS

This cross-sectional study involved 256 participants with and without ONL. The craniocervical and craniofacial characteristics of each participant were assessed through a software analysis of their cephalograms, containing 37 variables. Sex-based and age-based stratified analyses were also performed. The intergroup differences were examined by the independent sample t-test and the Mann-Whitney U test. Two-way ANOVA was used to assess the effects of gender and ONL status on craniocervical posture and facial morphology.

RESULTS

In overall analysis, the ONL group showed greater C0-C1 and craniocervical angle than the normal group. Several craniofacial variables (SNA, ANB, MP-NPog, angle of convexity, convexity of point A, and U1-NA) also differed significantly. In age-stratified analysis, adult patients showed results consistent with the overall trend. For stratified analysis based on sex, the differences of male subjects in C0-C1, craniocervical angle, SNA, and MP-NPog between the two groups were statistically significant. For female subjects, the differences in C0-C1, craniocervical angle, ANB, and U1-NA between the two groups were statistically significant. Two-way ANOVA revealed no significant interaction effect between gender and ONL status.

CONCLUSIONS

ONL is associated with pronounced forward head posture and distinct craniofacial feature. These morphological alterations may serve as diagnostic indicators for ONL.