Analysis Of Risk Factors For Complications Of Tissue Expander In Auricular Reconstruction

Objective:The clinical data of patients with congenital microtia who underwent tissue expander in auricular reconstruction were analyzed retrospectively,and to explore the risk factors and prevention and treatment of complications of the first stage tissue expander implantation in patients with congenital microtia,and to establish a Logistic regression prediction model to provide reference forclinical prevention of complications of dilatation method.Methods:According to the inclusion and exclusion criteria,the clinical data of the patients who underwent full-expansion auricular reconstruction in the Department of Plastic Surgery of the Second Affiliated Hospital of Kunming Medical University Hospital from June 2018 to December 2022 were retrospectively analyzed.They were divided into complication group according to whether there were complications（n=26）and the uncomplicated group（n=123）,statistical analysis was performed on each variable by t test,chi-square test,analysis of variance,Fisher’s exact probability method,Mann-Whitney U test and Kruskal-Wallis test,and those with statistical Variables of clinical significance（P<0.05）.Different complications were compared between groups according to the results of univariate analysis,and the variables with statistically significant differences were screened out（P<0.05）.The statistically significant variables（P<0.05）in univariate analysis were introduced into the multivariate Logistic regression analysis model,and the Backward Conditional method was used for stepwise regression analysis.Independent risk factors were screened out with P<0.05 and a regression model was constructed to predict postoperative complications was established and the effectiveness of the model was evaluated.Results:From June 2018 to December 2022,there were 149 patients in the Department of Plastic Surgery of the Second Affiliated Hospital of Kunming Medical University Hospital who underwent full-expansion auricular reconstruction in the first stage with implanted tissue expander behind the ear.Complications occurred in 26cases（17.4%）after implantation of the expander,among which hematoma 1 case（3.9%）,2 cases（7.7%）of expander leakage or injection pot leakage,9 cases of infection（34.6%）,and 14 cases of exposure（53.8%）.Univariate analysis results showed that age,auricle Max type,external auditory canal condition,whether combined with facial dysplasia,smoking,drinking,operation time,embedding level,drainage volume,water injection volume,and hospitalization days（P<0.05）all had significant effects on the surgical results.Post-complications have an impact.The results of inter-group comparison showed that the amount of water injected into the expander in the infection group was lower than that in the exposure group,and the difference was statistically significant（P<0.05）.The results of multivariate analysis showed that auricle Max typeⅢ,postoperative drainage volume>65ml,expander water injection volume≥80ml were risk factors for postoperative complications.The above statistically significant risk factors were incorporated into the multi-factor Logistic regression prediction model,and the regression equation was btained:Logit（P）=2.948X₁+0.025X₂+2.473X₃（X₁:auricle Max type Ⅲ,X₂:drainage volume>65ml,X₃:water injection volume≥80ml）.The goodness of fit test of the model by Hosmer and Lemeshow showed that χ²=1.873,P=0.967（P>0.05）,and the model fit well.ROC analysis showed that AUC=0.942,95%CI（0.902-0.982）,which proved that the model had good predictive ability.Conclusion:The incidence of complications after first stage expander implantation in the treatment of congenital microtia with full-expansion ear reconstruction was 17.4%.The main complications were infection,dilator exposure,hematoma and expander leakage.Auricle Max classification typeⅢ,drainage volume>65ml,and water injection volume≥80ml are independent risk factors for complications of this operation.Based on this,the regression model for predicting the occurrence of complications can provide a reference for clinically reducing the occurrence of postoperative complications.