A clinical epidemiological study on congenital ear malformation (CEM)

Background: There is no report about the definition, classification and clinical epidemiological study of congenital ear malformation (CEM).Aims/Objectives: To investigate the definition, clinical classification and distribution of a large number of CEM cases, along with the clinical and epidemiological characteristics associated with congenital malformation of the middle and outer ear (CMMOE).

Material and methods: A total of 3231 cases (4714 ears) with CEM and related malformations were retrospectively analyzed, including 2,658 cases (4,064 ears) CEM and 573 cases (650 ears) preauricular fistulas and accessory ears, specifically related malformations to CEM.

Results: Among the 2,658 cases (4,064 ears) CEM, 64.9% cases were male and 35.1% were female. 52.9% cases with bilateral, 29.1% with right and 18.0% with left CEM. A subgroup of 1,050 cases (1,331 ears) was identified as CMMOE out of 1,090 cases (1,379 ears) microtia. In the CMMOE subgroup, 74.0% cases were male, 46.3% on the right side, 26.8% showed bilateral involvement. Out of the CMMOE with available images, there were 947 cases (1,105 ears). Additionally, related malformations including preauricular fistulas and accessory ears, were solely occured in 573 cases (650 ears), except for their occurrence simultaneously with CEM. The classification and distribution of CEM are as follows:1. 2658 cases of CEM (1) 69.9% of them were confined to the ear, including: ① the outer ear 2.6%, the middle ear 17.0% and the inner ear 32.4%, ② two parts simultaneous malformations of the outer ear, the middle ear and the inner ear 17.2%, ③ three parts simultaneous malformations of the outer ear, the middle ear and the inner ear 0.6%, (2) Multiple malformations including in CEM 29.1%; (3) syndromes related to CEM 1.0%.2. 1050 cases of CMMOE (1) 36.3% of them were confined to the middle and outer ears; (2) Multiple malformations associated with CMMOE 61.4%, including hemifacial microsomia 50.5%, accessory ears 9.8%, preauricular fistulas 9.2%, heart malformation 7.1%, and kidney malformation 2.0%; and (3) syndromes related to CMMOE 2.3%, (4) Complications of the ear 16.9%, mainly including otitis media 7.9%, outer ear canal cholesteatoma 6.3%, retroauricular abscess 1.1%, and nasal and pharyngeal complications 18.6%. The proportions of microcia grades I-Ⅴ based on the images of 1105 ears CMMOE were 5.2%, 10.5%, 74.1%, 6.9%, and 3.3%, respectively. Among the 1331 ears CMMOE, the incidence rates of outer ear canal atresia, stenosis, normal, and ossicles malformation were 86.5%, 9.9%, 3.6%, and 98.3%, respectively.Conclusion and Significance: Approximately 69.9% of CEM cases were confined to the ear itself, with the highest proportion being inner ear malformation alone. Multiple malformations were predominantly associated with CMMOE. Syndromes related to CEM were relatively rare. Among cases of microtia, 96.3% were classified as CMMOE. These cases were predominantly observed in males, right ear and exhibited characteristics such as grade III microtia, atresia of the outer ear canal, ossicles malformation, and multiple malformations. The multiple malformations frequently included hemifacial microsomia, accessory ear, preauricular fistula, as well as heart and kidney deformities. CMMOE often coexisted with ear infections, cholesteatoma, and complications in the nasal and pharyngeal regions.