OBJECTIVETo explore the incidence, degree, and pattern of rib cartilage calcification in congenital microtia patients, in order to provide reference for harvesting the rib cartilage, sculpturing cartilage framework.

METHODSFrom Jun. 2013 to Nov. 2014, 383 patients (age range, 6-45 years) underwent CT scans of the chest. 11 patients with bony diseases or traumatic history were excluded. The remaining 372 patients were divided by age into four groups as 6-15, 16-25, 26-35, 36-45 years old. Twenty patients (10 male and 10 female) were selected by the order of patient identification number in each age group, thus selecting a total of 80 patients (40 male and 40 female). Retrospective study of CT scans of the chest in 80 patients and the incidence, degree, and pattern of cartilage calcification of the sixth to eighth ribs were noted. A chi-square test is conducted to test whether there are significant difference between the variables through the SPSS 19.0 software.

RESULTSOverall, 40.4% (194/480) cartilage was calcified; female patients (47.50%, 114/240) showed higher frequency of calcification than male patients (33.33%, 80/240, P = 0. 025). Calcification rates of all age groups are 1.7% (2/120), 46.7% (56/ 120), 49.2% (59/120), 64.2% (77/120). Calcification rate of 6-15 years group is lowest in all groups (P < 0.05) while other three groups have no statistical significance (P > 0.05). Calcification rates of the sixth and sevent rib cartilage were higher than those of the eighth rib cartilage in all age groups except 6-15 years group, who had a similar rate of all three ribs. Calcification rate of all three rib cartilage was significantly increased with age. Calcification rates of the amle's rib cartilage and the female's in all age groups are 3.3% (2/60) and 0.0% (0/60) (6-15 years): 33.3% (20/60) and 60.0% (36/60) (16-25 years): 40.0% (24/60) and 58.3% (35/60) (26-35 years), 56.7% (34/60) and 71.2% (43/60) (36-45 years). In 6-15 years group calcification rates of male and female had a similar rate, while female's rates were higher than male's rates in other three groups. Male and females mainly had the granular type of calcification [70.0% (56/80), 63.2% (72/114)].

CONCLUSIONSFemales who are over 16 years old should pay more attention to the possibility of middle-severe calcification before harvesting rib cartilage. These patients should take CT examination if necessary. In addition, the patients who had previous operation, or traumatic history, rib deformity, or spine deformity should select the CT examination.