Effect Of Exceedingly Expansion Ratio On Surgical Outcome In Children With Microtia

Objective: Investigate the effect of exceedingly expansion ratio on surgical outcome in children with microtia.Methods: We reviewed the microtia cases underwent ear reconstruction in our department during 2015 Jan and 2018 Dec,including the gender,age,side,degree of malformation,expander specifications,exceedingly expansion ratio,surgical effect index including the rate of expander exposure,the incidence of skin grafting,the rate of the excellent reconstructed ear,the rate of the reconstructed ear with asymmetry craniometrical angle,the rate of framework exposure.Binary logistic regression analysis was performed to identify the effect of an exceeding expansion ratio on surgical outcomes.Results: A total of 32 children with microtia were included in this study.Among the 32 cases,24 cases were male while 8 cases were female.There were 10 cases with left side microtia,and 22 cases with right side microtia.The age was between 6 years and 10 months to 16 years and 9months with a median age of 9.00.Furthermore,Class IIb was noted in 3 cases while class III was 22 cases and class IV was 7 cases.The expander specification was 70 ml or 80 ml.The exceedingly expand ratio differed from 18.57% to 100.00% with an average of 59.08%±24.32.All patients were followed up to 6 months after the ear reconstrction or before the third operation(The longest follow-up time is 2 years and 4 months after surgery).The incidence of skin grafting,the rate of the excellent reconstructed ear,the rate of the reconstructed ear with asymmetry cranioauricular angle,skin grafting rate were 34.38%,59.38%,78.13% respectively.Regression analyses revealed that the percentage of excellent reconstructed ear(OR=1.076,95%CI: 1.003 ~1.155,P =0.042),the percentage of the reconstructed ear with asymmetry cranioauricular angle(OR=1.210,95%CI: 1.005~1.455,P =0.044)were associated with a higher level of exceedingly expanding ratio,while the incidence of skin grafting(OR=0.922,95%CI: 0.855~ 0.995,P =0.036)was converse.The incidences of skin grafting of which exceedingly expand≤53.75% compared to which > 53.75% were 66.67%vs5.88% respectively(P=0.0005).No expander or framework exposure occurred during follow-up.Conclusioins: More skin can be supplied to cover the framework by using usual expander(70ml or 80ml)and increasing the ratio of exceeding expansion in ear reconstruction.,so that the incidence of skin grafting can be reduced,and the effect of the reconstructed ear is significantly improved.Exceedingly expansion with a higher ratio of 53.75% can significantly reduce the incidence of skin grafting.