[Cryptotia: morphometric characteristics and statistical observations]

In the present study we made actual measurements of the normal and affected auricles of patients with unilateral cryptotia and performed a comparative statistical analysis. We also made a compilation of our own cases and other cases reported in Japan, and reported the results of our statistical analyses.

The subjects of this survey were 36 patients who came to our outpatient clinic with a chief complaint of cryptotia between 1983 and 1990. Measurements of auricle were made according to the Martin method. We also compiled all cases of cryptotia reported in the Japanese literature to date in which the sex of the patients and affected side were clearly recorded and reviewed associated abnormalities and familial occurrence.

Auricle measurements of auricle showed the vertical axis of the affected auricle to be significantly shorter than normal, revealing severe shortening of the upper 1/3 of the auricle. There was no statistically significant difference between the normal and affected auricles on the horizontal plane. The results of our compilation of reports in the literature to date show a male-female ratio of 2:1, a right-left-bilateral ratio of 5:2:3, the presence of other anomalies in 9.2% (7/76), and familial occurrence in 6.4% (15/236).

(1) Based on measurements of auricle, cryptotia is defined as a deformity of the upper 1/3 of the auricle and is produced by the sum total of force vectors operating inferiorly and medially. Moreover, based on the data obtained as a result of the measurements performed in this study, there was greater deformity along the vertical axis, and the downward vector was obviously stronger than the inward vector. (2) There were 3 cases of unilateral cryptotia with an adhesion-like deformity of the helix in the normal ear, and the theory that the upper portion of the auricle becomes embedded secondary to cartilage deformity seemed plausible. (3) A compilation of cases in Japan showed a male-female ratio of 2:1 and a right-left-bilateral ratio of 5:2:3, differing little from the ratios in our cases. (4) Familial occurrence in our cases was found in the patient's mother of 2 cases and a male cousin and uncle in 1 case each, suggesting a strong hereditary influence.