Clinical and genetic characteristics of 131 cases of congenital preauricular fistula

Abstract

Objective:To investigate the clinical and genetic characteristics of congenital preauricular fistula. Method:The clinical data of 131 patients（143 ears） with congenital preauricular fistula. The patient's age distribution, sex ratio, side of fistula, number of fistula, location of fistula, concomitant malformation, course of infection, previous infection history, previous treatment history and family history were counted. Result:In this study, 54 cases（41.2%） were juveniles, 77 cases（58.8%） were adults, 118 cases（90.1%） were under 40 years old, and 13 cases were（9.9%） over 40 years old. The male to female ratio is 1：1.85, and the ratio of unilateral to bilateral patients is 3.7：1. The male to female ratio was 1：2.03 in unilateral patients and 1：1.33 in bilateral patients. The preauricular skin pit of 124 cases（94.7%） located at the anterior margin of the ascending limb of the helix, and The pit of 7 cases（5.3%） located at other areas such as the crus of helix（3 cases, 2.3%）, the anterosuperior wall of the external auditory canal（3 cases, 2.3%）, and the lower edge of the lobule（1 case, 0.7%）. 2 cases（1.4%） showed 2 fistulas in the anterosuperior wall of the external auditory canal, and 1 case showed a false fistula in front of the ascending limb of the helix, 141 ears（98.6%） showed a single fistula. Two cases were accompanied with accessory auricles, and one case with mild microtia. Before operation, 18 ears were non-infectious（12.6%） and 125 ears were infected（87.4%）. Among the infected ears, the course of infection ranged from 3 days to 1 year, 110 ears（76.9%） were in the course from 0 to 3 months. 14 ears had pre-operation history（9.8%） and 62 ears had incision and exclusion history（43.4%）. 84 people（64.1%） had no family history and 47 people（35.9%） had family history. There were 26（19.8%） families showed vertical inheritance, 7（5.3%） families showed atavistic pattern, and 14（10.7%） families showed familial susceptibility. Conclusion:CPF is more common in female, and usually unilateral and occasionally bilateral. there is no significant difference between the left and right sides. The vast majority of patients showed a single fistula at the anterior margin of the ascending limb of the helix. Very few patients had fistula at the crus of helix, the upper wall of the external auditory canal, and the lower edge of the lobule. CPF can be accompanied with accessory auricles and mild microtia. The clinical features of special type of preauricular fistula and syndromic preauricular fistula should be emphasized. Most patients are in an acute infection period, and drainage of the abscess is the main treatment for the infection. CPF is often sporadic. It may be inherited as an autosomal dominant incomplete pattern with variable power of expression.