Evaluation Of The Effect Of Buck’s Fascia In The Repair Of Hypospadias In Children And Histomorphological Study Of Buck’s Fascia In Animal Experiment

Part Ⅰ Evaluation of the effect of Buck’s fascia in the repair of hypospadias in childrenBackground and ObjectiveHypospadias has been a hot issue in pediatric urology for a long time,because of the increasing incidence rate and unsatisfactory surgical effect.The methods of urethral reconstruction are complicated.With the increase of the severity of the deformity,the incidence of postoperative complications such as urinary fistula,urethral stricture,urethral diverticulum,penile ventral curvature(VC),and unsatisfactory penile appearance is increasing.Even mild hypospadias may also have various complications.At present,there is an international consensus that the application of reliable tissue covering urethroplasty after hypospadias surgery can significantly reduce the occurrence of complications and improve the surgical effect,but different surgeons still have different tendencies when selecting new urethral outer covering materials.Among the numerous covering materials,the urethral sponge,Dartos fascia(DF)and other materials near the urethra are the most convenient and widely used.In the past two decades,there has also been continuous application of tissue engineering materials such as autologous platelet-rich fibrin(PRF),small intestinal submucosal(SIS),acellular dermal matrix(ADM),tissue sealant and other tissue engineering materials.The application of these coverage materials and methods has gone through the process of popularization,depression and center differentiation from implementation to reflection,suggesting that the selection of these methods or materials is still closely related to the experience of surgeons and specific treatment methods.The research team selected the Buck’s fascia(BF)and used it as the intermediate layer tissue to cover the new urethra,and through the anatomical and histological study of BF,To explore how to apply the anatomical technique of BF and penis glans integral-covering(BFIC)technique to restore the outer anatomical relationship of the penis in various common hypospadias surgery,and to study the operation method of BF in repairing the outer anatomical structure of the penis based on this idea,so as to provide a new idea for the surgical management of hypospadias and improve the surgical effect of hypospadias.MethodsTo study the anatomical method of BF in hypospadias operation and its application in different hypospadias operation methods,and evaluate the effect through various ways.1)To understand the anatomical differences of BF in normal penis and hypospadias,and to study the anatomical structure relationship between BF and penis glans and urethral plate(UP)tissues in hypospadias,and to study the integral anatomical covering technology of BF and glans wings(BFIC technology),and to restore the external anatomy of penis.To study its application in common surgical procedures of hypospadias,including preserved urethral plate(PUP): Tubularized incised plate urethroplasty(TIP),Inner preputial inlay graft urethroplasty(Inlay-graft),Preputial onlay graft urethroplasty(Onlay-graft),Flip-flap urethroplasty(Mathieu-Graft);The operation of transected the urethral plate(TUP): Transverse preputial island flap(TPIF),Free preputial tube graft urethroplasty(Free-tube graft).2)From January 2020 to December 2021,the research team treated 48 children with primary hypospadias with the TIP operation of BFIC technique,collected relevant clinical data and postoperative complications,and compared the results with the follow-up data of 59 children with primary hypospadias with the traditional TIP operation performed by the same surgeon from March 2018 to December 2019,for statistical analysis.3)The research team reviewed and analyzed the multi-center data of BF application from January 2016 to November 2020,including Anhui Provincial Children’s Hospital(AH),Beijing Children’s Hospital(BJ),Sichuan Provincial People’s Hospital(SC),Xiamen Maternal & Children’s Health Hospital(XM).Collect and analyze the surgical data and complications of postoperative follow-up.Results1)BF is closely related to the anatomical structure of the penis glans tissue.It can be dissected and dissociated from both sides of the penis cavernous body and the urethral plate as a whole.BFIC can be used in TIP,Inlay-graft,Onlay-graft,Mathieu-grade,TPIF,Free-tube grade and some hybrid procedures2)In the comparison between BFIC-TIP and conventional TIP procedure,the operation time of BFIC-TIP was longer than that of traditional TIP group(P<0.05).In terms of postoperative complications,the incidence of urinary fistula and urethral dehiscence in BFIC group was lower than that in traditional TIP operation,with statistically significant difference(P<0.05).In the incidence of urethral diverticulum and urethral stricture,there was no statistical difference between the two groups.3)In the multi-center study in four medical centers,1386 patients were followed up to apply BF technique in hypospadias surgery,including 179 patients with AH,62 patients with BJ,235 patients with SC,and 910 patients with XM.Postoperative follow-up was carried out by telephone,email,outpatient interview and network platform.A total of 143 cases(10.3%)of complications were collected.There were 114 cases(9.0%)of primary operation complications and 29 cases(23%)of reoperation complications.The incidence of complications of primary surgery and reoperation in all medical centers was 8.0%～12.9% and 15.4%～28.8%respectively.The total incidence of complications of TIP and Free-tube graft surgery was 9.8% and 9.9% respectively.The incidence of urinary fistula in primary TIP was 33 cases(4.9%).There was no statistically significant difference in the complications of the four medical centers(P>0.05).Conclusions1)BF is deficiency on the ventral side of the penile body of hypospadias,which is anatomically different from normal penile tissue.BF can form BFIC technology with complete anatomy and preservation of penis glans tissue in hypospadias,and can be used to restore the outer anatomical structure of the penis in hypospadias.2)BF integral-covering technology-BFIC combined with TIP procedure is safe and effective in repairing hypospadias in children.Compared with the traditional TIP operation,in addition to the slightly longer operation time,the complication rate of urinary fistula and urethral dehiscence is significantly reduced.3)The results of the multicenter application of the BFIC suggest that it can be combined with a variety of surgical procedures in preserve or cut off the urethral plate for the proximal,mid-shaft,distal,primary or re-operation hypospadias.Part Ⅱ Histomorphological study of Buck’s fascia in animal experimentBackground and Objective Hypospadias,as one of the most common abnormal diseases of urogenital system,has an increasing incidence.At present,the treatment of hypospadias can only be operated.However,postoperative complications and their recurrence have increased the frustration of surgeons and patients.Understanding the anatomical structure of hypospadias penis will help surgeons plan and innovate surgical procedures to improve appearance and function.Most scholars only do pathological research on gross specimens,but have not found the differences among different layers of penis tissue of hypospadias.Therefore,this study will establish a congenital hypospadias model with SD rats as experimental animals,and analyze the differences in tissue repair function,blood vessels,collagen fibers and nerves distribution among different layers of tissues,so as to provide theoretical basis for understanding the pathological changes of penis in hypospadias and improving surgical methods.Methods The model of congenital hypospadias was established by feeding finasteride to pregnant rats,and the penis of male rats with hypospadias was dissected.The expression levels of growth factors(Platelet-derived Growth Factor(PDGF),Epidermal Growth Factor(EGF),Fibroblast Growth Factor(FGF),Hepatocyte Growth Factor(HGF),Transforming Growth Factor-β1(TGF-β1)),androgen receptor(AR)and estrogen receptor(ER1、2)in different tissues were detected by QPCR.The athological changes of penis in male rats with hypospadias were studied by HE staining,Masson staining,silver glycinate staining and vascular analysis.Results 1)Establishment of animal model: At last,there were 18 male rats with obvious hypospadias.The mortality rate of this animal model is 25%,and the morbidity rate is 85.7%.Compared with the control group,the weight of the experimental group decreased with statistical significance(P <0.05).Anogenital distance(AGD)was shortened in the experimental group,which was statistically significant(P <0.05).Compared with the control group,anogenital index(AGI)of the experimental group decreased,but there was no statistical significance(P >0.05).2)Expression level of growth factors: The genes expression levels of PDGF,HGF,EGF and TGF-β1 in Buck’s fascia(BF)were higher than those in Dartos fascia(DF),with no statistical significance(P >0.05).The gene expression of FGF gene in BF was lower than that in DF,and there was no statistical significance(P >0.05).The genes expression of FGF,HGF and TGF-β1 genes in fascia layer was lower than that in corpus cavernosum penis,with statistical significance(P <0.05).3)Expression of AR and ESR: The gene expression level of AR in BF was higher than that in DF(P >0.05)and lower than that in corpus cavernosum penis(P <0.05).The gene expression level of ESR1 in BF was lower than that in DF(P >0.05)and higher than that in corpus cavernosum penis(P >0.05).The gene expression level of ESR2 in BF was higher than that in DF(P >0.05)and lower than that in corpus cavernosum penis(P<0.05).4)Pathological changes of penis tissues in hypospadias: HE staining showed that the epidermal tissue of hypospadias proliferated,muscle fibers were disordered and inflammatory cells infiltrated.Masson staining showed that collagen fibers in DF were less distributed,while collagen fibers in BF were widely distributed,with eep staining and thick fibers.Silver glycinate staining showed that nerve fibers in DF were less distributed,nerve fibers in BF were widely distributed,with deep staining and large section,urethral nerve fiber bundles were distributed,and only a few nerve fibers were found in corpus cavernosum.5)Distribution of blood vessels: The density of micro vessels in BF is higher than that in DF,and the highest density of blood vessels is in urethral tissue.According to the measurement of large blood vessels,we found that the width and wall thickness of large blood vessels were higher in the BF of hypospadias male rats compared with the other three groups of tissues,and the width of BF was higher than that of urethra and penis tissues,which was statistically significant(P <0.05).The vascular wall thickness of BF is thicker than that of DF,urethra and corpus cavernosum penis,with statistical significance(P <0.05).Conclusions 1)The animal model of hypospadias in rats was successfully induced by finasteride,and the method was feasible.2)The genes expression level of growth factor in BF is higher than that in DF,which proves that the intact BF and Penile head tissue can be used to restore the external anatomical structure of hypospadias penis,and its postoperative complications are significantly reduced.3)Histological observation showed that the collagen fibers in BF were more widely distributed than those in DF,with thick fibers,wide distribution of nerves and thickening of large vessels.