Analysis Of Related Risk Factors For Urethral Fistula After TIP Operation In Hypospadias

Background:Hypospadias is one of the common malformed genitourinary system in children,the incidence is about 1/200～1/300,and the trend is increasing year by year.Surgery is currently the treatment for hypospadias.Although there are hundreds of surgical methods,the incidence of postoperative complications such as urethra 1 fistula,urethral stricture and urethral diverticulum is still high,among which urethral fistula is the most common postoperative complication after surgery for hypospadias.Among the hundreds surgical methods,Tubularized incised plate(TIP)was reported by Snodgrass in 1994 firstly.Since its less postoperative complications and better appearance of the penis after operation,TIP has been widely used in the treatment of hypospadias.Continuously improved in surgical details by Snodgrass and doctors around the world,it has become one of the most popular surgical methods for the treatment of hypospadias.There are many factors that affect the incidence of postoperative complications after TIP surgery.In addition to strict control of surgical indications,age and width of urethral plate may affect the occurrence of postoperative complications such as urethral fistula.The occurrence of urethral fistula may be related to many factors.Some studies have shown that proteins in the prepuce of hypospadias are abnormally expressed.Therefore,whether the abnormally expressed proteins in the prepuce are the risk factor for urethral fistula and other complications is worth further study.Objective:The aim is to search for proteins expressed in prepuce that are associated with postoperative complications of hypospadias,and to explore the risk factors for urethral fistula after TIP surgery for hypospadiasMethods:75 children with hypospadias who underwent TIP surgery from January 2018 to June 2020 were collected.All of them got surgical treatment for the first time.The incidence of urethral fistula was analyzed after 3-6 months of postoperative follow-up.To analyze the relationship between the occurrence of urethral fistula and the age of the child,the type of hypospadias,the width of urethral plate,the length of the formed urethra,whether the dorsal membrane albugoma was folded or not,and the type of urethral catheter after the operation Proteomics analysis was used to identify the differentially expressed proteins in prepups collected from 6 cases of hypospadias in 2 groups.Immunohistochemical staining,immunofluorescence staining and Western blotting were used to test the expression of differentially expressed proteins screened by proteomics in the prepuce tissues.Results:The results of Label-free mass spectrometry showed that there were 32 proteins differentially expressed in the hypospadias preputure samples from the urethral fistula group compared with the non-complication group,among which 28 proteins were highly expressed and 4 proteins were low expressed,the differences were statistically significant(P<0.05),and the difference of MPO expression was the most obvious.Thirty-two proteins were placed in the STRING database,among which 19 proteins were interrelated,and MPO and its related proteins were at the key positions.GO/KEGG enrichment analysis showed that the differences existed in a variety of cell biological behaviors,including the involvement of MPO in mediating immune stress.DAVID protein function analysis showed that there are 5 proteins associated with acute inflammation,and the up-regulated proteins included MPO,cAMP,ANXA3,DEFA3,and S100A9,among which the up-regulated expression of MPO was the most obvious.KEGG enrichment identified the top 9 pathways with the minimum P value,including the IL-17-mediated acute inflammatory immunomodulatory pathway that MPO participates in.We found that MPO is located in an important position of KEGG signaling pathway and participates in this process.In conclusion,MPO,which has the most obvious difference,was selected as the target protein of this study.Further immunohistochemical staining,fluorescence staining and Western blotting detection confirmed that the expression of MPO in the prepuce tissue of the urethral fistula group was significantly higher than that of the non-urethral fistula group(P<0.05).The statistical analysis of 75 children with TIP after postoperative follow-up showed that the incidence of urethral fistula was significantly correlated with the age of operation(P<0.05).The width of the glans urethral plate in the urethral fistula group and the glans urethral plate in the non-urethral fistula group were,respectively.Thhere was no significant statistical difference between the two groups(P>0.05).There were no significant differences in average urethral plate width,shaped urethral length,urethral plate width after incision,urethral tube type and hypospadias type between the urethral fistula group and the non-urethral fistula group(P>0.05).Conclusion:Urethral fistula is the main complication after TIP urethroplasty.Age of operation is an independent risk factor for urethral fistula after TIP surgery.The expression of MPO in the prepuce tissue of hypospadias was significantly different between the complication group and the non-complication group,and the high expression of MPO in the prepuce tissue suggested an increased risk of urethral fistula after TIP surgery.