Odontoid calcification and crowned dens syndrome: data from a Chinese center.

Objectives: To assess the prevalence of calcification surrounding the odontoid process (odontoid calcification) with crowned dens syndrome (CDS) and without CDS (non-CDS) and investigate factors that may related to the onset of CDS.

Methods: Retrospective review of consecutive patients visited Sir Run Run Shaw Hospital between 1 January 2018 and 5 November 2019 who were identified to have odontoid calcification on cervical computed tomography (CT) images. Those who presented with an acute or subacute episode of cervico-occipital pain were defined as CDS, others were non-CDS.

Results: We diagnosed 69 cases of odontoid calcification among 2902 cervical CTs of 2556 patients (69/2556, 2.70%), 19 (19/2556, 0.74%) cases of which were CDS, 50 (50/2556, 1.96%) cases were non-CDS. Mean age was 71 (54-86) years old in odontoid calcification patients. The male-to-female ratio of patients with odontoid calcification was 27:42 (0.64). The prevalence of odontoid calcification was 69/1497 (6.14%) in individuals over 50 years old, The prevalence was 0.59% (4/679), 5.05% (26/515), 11.49% (27/235) and 20% (12/60) in patients aged 50-59, 60-69, 70-79 and 80-89 years old, respectively. Age and female gender were predictive factors of odontoid calcification. Lower hemoglobin (Hgb), red blood cell count (RBC), higher C-reactive protein (CRP), pain scale score were found in CDS patients comparing with non-CDS group. No difference of age, gender, hypertension, diabetes mellitus, smoking, alcohol history, creatinine, white blood cell count, mean corpuscular volume, uric acid, calcium was found between the two groups.

Conclusions: Odontoid calcification is a common radiological entity in patients older than 50 years. Lower Hgb, RBC, higher CRP, pain scale score were found in CDS patients comparing with non-CDS.