Characteristics of rib cartilage calcification in Asian patients

IMPORTANCE Rib cartilage from the sixth, seventh, and eighth ribs offers a long cartilaginous curvature, making the material reliable for grafting. Calcification of cartilage causes unexpected absorption, difficult manipulation, and donor site morbidity. Most studies of calcification were performed in Western countries. OBJECTIVE To investigate the incidence, degree, and pattern of rib cartilage calcification in Asian patients. DESIGN, SETTING, AND PARTICIPANTS Retrospective study of computed tomographic scans of the chest in 120 patients (60 male and 60 female). The incidence, degree, and pattern of cartilage calcification of the sixth through eighth ribs were noted. The patients were stratified into 6 age groups, and 20 patients (10 male and 10 female) were selected for each group. The degree of calcification was assessed as 0%, 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. Meaningful calcification was defined as 26% or greater. The pattern of calcification was classified as marginal, granular, and central. EXPOSURE Computed tomographic scans of the chest. MAIN OUTCOMES AND MEASURES Degree of calcification, presence of meaningful calcification, and calcification pattern. RESULTS Overall, 50.8% of cartilage was calcified, and female patients showed more frequent calcification than male patients (59.4% vs 42.2% [P < .001]). Calcification rates of the sixth and seventh rib cartilage were higher than those of the eighth rib cartilage in all age groups except teenagers, who had a similar rate for all 3 ribs. Calcification of the sixth and seventh rib cartilage significantly increased with age. A meaningful calcification rate was very low in males younger than 60 years, whereas the rate was relatively higher in females than males for all age groups. Males predominantly had the marginal type of calcification, whereas females predominantly had a granular type. The rate and pattern of calcification had no relationship to age. CONCLUSIONS AND RELEVANCE In Asian patients, males younger than 60 years show a very low incidence of calcification, whereas females 30 years or older show a relatively high incidence of meaningful calcification. Asian females also show a predominantly granular or central pattern of calcification that may hinder proper harvest and incision of the rib cartilage. These differences in the incidence and pattern of rib cartilage calcification need appropriate preoperative attention.