PEDIATRIC UROLOGY Urology Journal/Vol 20 No. 3/ May-June 2023/ pp. 162-166. [DOI: 10.22037/uj.v20i.7438] Analysis of The Curative Effect of Tubularized Incised Plate Urethroplasty for Distal Hypospadias with The Dysplastic Corpus Spongiosum Covering Technique Linghua Ji1*, Shuqing Chen2*, Yuehua Chen1, Jun Zhao1, Qiyou Yin1, Hua Xian1, Wenliang Ge1# Purpose: To investigate the use of tubularized incised plate (TIP) urethroplasty for distal second- and third-degree hypospadias to free the dysplastic forked corpus spongiosum and Buck’s fascia, which are used as a covering ma- terial for the new urethra, thereby reducing the incidence of urinary fistula and other complications in the coronal sulcus. Materials and Methods: Clinical data of 113 patients with distal hypospadias treated with TIP urethroplasty from January 2017 to December 2020 were retrospectively analyzed. The study group comprised 58 patients (use of dysplastic corpus spongiosum and Buck’s fascia to cover the new urethra), and the control group comprised 55 patients (use of dorsal Dartos fascia to cover the new urethra). Results: All children were followed up for more than 12 months. In the study group, 4 patients developed urinary fistulas, 4 developed a urethral stricture, and no case developed glans fissure. In the control group, 11 patients developed urinary fistulas, 2 developed a urethral stricture, 3 developed a glans cracking. Conclusion: Using the dysplastic corpus spongiosum to cover the new urethra increases the amount of tissue in the coronal sulcus and reduces the incidence of urethral fistula, but it may increase the incidence of urethral stricture. Keywords: Buck's fascia; dartos fascia; corpus spongiosum; dysplasia; hypospadias; TIP operation INTRODUCTION Hypospadias is a common congenital malformation of the urinary system and requires early treatment. The incidence rate of hypospadias is high in boys, and it is increasing year by year.(1) TIP urethroplasty was first performed by Snodgrass in 1990 and officially reported in 1994.(2) TIP urethroplasty is a simple operation that can retain the urethral plate to the greatest extent and has a relatively low postoperative complication rate, and the urethral orifice is similar to that of the normal urethra. It has quickly become the mainstream opera- tion for distal hypospadias. However, the incidence of urethral fistula, especially at the coronal sulcus, has been the most common in tip, which is related to the thin skin, less tissue, poor blood supply at the coronal sulcus, and the intersection of the two tissues.(3,4) During the operation of 58 patients with distal hypospa- dias from January 2017 to December 2020, we dissoci- ated the dysplastic corpus spongiosum and buck's fas- cia together as the covering material of the new urethra, hoping to reduce the incidence of urethral fistula and observe the incidence of other complications. We con- ducted a retrospective comparative study between this method and traditional tip surgery, and now the results are reported as follows. 1 Department of Pediatric Surgery, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China. 2.Department of Medical College of Nantong University, Nantong, 226001, Jiangsu, China. *Correspondence: Department of Pediatric Surgery, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, China. Tel: 13962854122. Fax: 13962854122. E-mail: gewl@ntu.edu.cn Received November 2022 & Accepted January 2023 MATERIALS AND METHODS Study population and study design 113 cases of hypospadias were distal type (I-II°), with- out chordee or chordee angle <15°. TIP covered by hy- poplastic corpus spongiosum and its continuous Buck's fascia was classified as the study group, and TIP cov- ered by dorsal Dartos fascia was regarded as the con- trol group. All patients were operated for the first time and were completed by the same surgeon. Except for other system malformations and surgical contraindi- cations, the routine examination before operation was performed. The study has been approved by the ethics committee of the hospital. The treatment effects of the two groups were compared quantitatively by comprehensive evaluation methods such as the incidence of complications and the ques- tionnaire of family members' satisfaction. Surgical technique Pull the penis head (Figure 1a, 2a), and cut the mem- branous part of the urethral opening to the proximal end to the normal corpus spongiosum. Cut parallel along both sides of the urethral plate and extend to the front of the penis head, leaving the urethral plate about 1cm wide. Cut parallel along both sides of the urethral plate and extend to the front of the penis head, leaving the urethral plate about 1cm wide. Make a circular incision about 0.5cm from the inner prepuce plate to the coronal sulcus, and separate and deglove the dorsal side of the penis along the surface of buck's fascia. Pay attention not to damage the poorly developed and forked corpus spongiosum in this step. After degloving, according to the urethral inner diameter and penis development, se- lect F8 silicone double chamber bladder urinary tube as the stent tube and drain urine, and carefully free the poorly developed corpus spongiosum on both sides of the urethral plate (Figure 1b, 2b), The lateral buck's fascia was dissociated together, and then the distal cav- ernous body was dissociated from the surface of the tunica albuginea, so that the cavernous bodies on both sides were sutured to the midline without tension to cover the new urethra. Then free the glans to fully ex- pand both sides of the glans, and trim the tissues in the glans to achieve the effect of reducing the volume in the glans, so that when the glans is sutured, it can wrap the urethra without tension. The urethral plate is cut longi- tudinally in the middle, reaching the shallow surface of the white membrane of the corpus cavernosum of the penis. The urethral plate wraps around the urinary tube without tension, and the 6-0 absorbable thread is turned inward to form a new urethra. The dysplastic corpus spongiosum and buck's fascia bifurcated on both sides of the urethral plate were sutured to the midline to cover the coronal sulcus of the new urethra (Figure 1c, 2c). Properly cut the foreskin and then sew and wrap the penis (Figure 1d, 2d). The gauze was removed 5 days after operation, and the catheter was removed 2 weeks after operation on average. Evaluations and follow-up Recheck at 4 weeks, 8 weeks, 16 weeks and 32 weeks after operation, and then every half a year. During the period, the evaluation of the patient's family members on the penis appearance, urination, hygiene and the number of operations was collected through a question- naire to obtain a comprehensive satisfaction evaluation. Statistical analysis Outcome measures: Age, BMI, complications (urinary fistula, urethral stricture, incision infection and rupture, urethral diverticulum), satisfaction pre-operation and 4, 8, 16 and 32 weeks after operation. Shapiro Wilk func- tion was used to test the normality of measurement data, Levene test was used to test the homogeneity of var- iance, and independent measurement data conforming to the normal distribution was expressed in . The two groups were compared by independent sample t-test; The measurement data that do not conform to the nor- mal distribution are expressed by the median (interquar- tile interval), and the independent samples are tested by Wilcoxon test of two independent samples. The count- ing data were expressed in percentage, and the compar- ison of counting variables (complication rate) was per- formed by χ2 test or Fisher exact test, P < 0.05 indicates that the difference is statistically significant. RESULTS 113 patients in the study group and the control group were followed up for more than 1 year. There were 58 patients in the study group and 55 patients in the control group. The average age of patients in the study group was 31.7 ± 6.76 months, while that in the control group was 30.7 ± 4.74 months. There was no significant dif- ference (P > 0.05). There was no significant difference TIP with corpus covernusum covering method-Ji et al. Variables Research Group Control Group t P Age, months; mean ± SD (range) 31.7 ± 6.76 30.7 ± 4.74 0.919 0.36 BMI, kg/m2; mean ± SD (range) 23.8 ± 2.48 24.1 ± 2.28 -0.467 0.64 Table 1. Comparison of basic information of two groups of patients. Figure 1. Pictures of key surgical steps: 1a. Penis head traction; 1b. Free bifurcat- ed dysplastic corpus spongiosum and its continuous Buck's fascia after degloving penile skin (as shown by the blue arrow); 1c. Close the cavernous body and Buck's fascia to cover the new urethra (as shown by the yellow arrow); 1d. Penis appear- ance after urethroplasty. Figure 2. Hand drawing of key surgical steps: 2a. Penis head traction; 2b. Free bifurcated dysplastic corpus spongiosum and its continuous Buck's fascia after de- gloving penile skin (as shown by the blue arrow); 2c. Close the cavernous body and Buck's fascia to cover the new urethra (as shown by the yellow arrow); 2d. Penis appearance after urethroplasty. Pediatric Urology 163 between the two groups in BMI (P > 0.05). The overall complication rate in the study group (13.79%) was lower than that in the control group (29.09%), with a statistically significant difference (95%CI: 0.15-1.00, OR = 0.39, P = 0.047). The over- all incidence of urinary fistula was 6.9% and 20% re- spectively, with a statistically significant difference (95%CI: 0.09-0.99, OR = 0.39, P = 0.041); There were 1 case of coronary fistula in the study group and 8 cases in the control group. The difference between the two groups is statistically significant (95%CI: 0.01-0.83, OR = 0.10, P = 0.015). There was no statistically sig- nificant difference between the two groups in penile body fistula (95%CI: 0.12-7.39, OR = 0.95, P > 0.05). In the study group, urethral stricture occurred in 4 cases (6.9%), without glans dehiscence; In the control group, urethral stricture was found in 2 cases (3.64%), and glans dehiscence in 3 cases (5.45%). The satisfaction scores of the pre-operation and 32 weeks after surgery, and the difference between sat- isfaction scores of 32 weeks after surgery and the pre-operation were compared. There was no significant the difference between the two groups in preoperative satisfaction scores (P > 0.05), but there was significant difference between satisfaction scores of 32 weeks af- ter surgery and the difference of 32 weeks after surgery and the pre-operation in two groups (P < 0.001). DISCUSSION Hypospadias is caused by the fusion obstacle of the ure- thral fold at the midline, which leads to the cracking of the ventral urethra, and the absence or dysplasia of the corpus spongiosum and deep and superficial fascia at the ventral urethral orifice of the penis.(5) Surgery is the only treatment option for hypospadias.(6) Urinary fistu- la is one of the most common complications of hypo- spadias. The main reasons include poor blood supply of new urethral covering materials, high tension, less coverage levels, lack of experience of surgeons and so on.(7) Therefore, adding reliable covering materials be- tween the new urethra and the skin is very important to reduce the incidence of postoperative complications of hypospadias. In 2000, Yerkes first reported a bifurcation deformity of the penile corpus spongiosum in patients with hypo- spadias and used it as a new urethral covering materi- al to establish the novel “Y-to-I technology,” which is considered to have the effect of reducing the incidence of urinary fistula.(8) In this study, we selected cases of distal hypospadias as the research object. There were 58 cases in the study group, and 4 cases had urinary fistula. The incidence of urinary fistula was 6.9%, which was significantly lower than 20% in the control group (P = 0.04). Dodat has achieved good results in the treatment of distal hypospadias with Spongioplasty.(9) He believes that this operation is applicable to all distal hypospadi- as, which can effectively reduce the incidence of uri- nary fistula and reduce the difficulty of correcting pe- nile curvature. Bhat found that the thicker the cavernous body, the lower the incidence of urinary fistula after tip. (10) It is suggested that Cavernoplasty of penis should be taken as a necessary step. We believe that because most of the urethral cavernous bodies of the proximal hypospadias penis are stunted or missing, while most of the distal hypospadias penis has a relatively thick dysplastic corpus spongiosum (as shown in Figure 1b), which is Y-shaped and distributed on both sides of the urethral plate, with rich blood supply. Using it as a cov- ering material can effectively increase the tissue thick- ness of the new urethra. At the same time, this method can make the repaired penis more similar to the nor- mal penis structure and obtain a more satisfactory ap- pearance. In the control group, the dorsal dartos fascia transfer was used to cover the new urethra. Because the blood supply of the dartos fascia flipped from the dorsal side of the penis to the ventral side was poor, and the adhere of tissue was poor, there was a high possibility of ischemic necrosis and tissue contracture after opera- tion, which led to a high incidence of urinary fistula and glans cracking. Hafez Used the pedicled dartos fascia flap and cavernous body as the covering material when performing tip surgery on patients with scrotal hypo- spadias, and believed that the pedicled dartos fascia was the key to reduce postoperative complications.(11) In this regard, the operator believes that proximal hypospadias often need to cross the urethral plate, which can lead to more blood supply damage. At the same time, proximal hypospadias have high urethral orifice, early urethral development "stagnation", and poor development of corpus spongiosum, resulting in poor blood supply of covering materials and weak tissue volume.(12) There- fore, this operation is not suitable for the treatment of proximal hypospadias. After verification, Bhat believed that there was no dif- ference between the dysplastic corpus spongiosum and dartos' fascia in reducing urinary fistula.(10) Hayashi be- lieves that Spongioplasty cannot reduce the incidence of urinary fistula in tip surgery.(13) It may be that the bifurcated corpus spongiosum fits closely with its con- Complications Research Group N (%) Control Group N (%) OR and 95%CI P Total complications 8 (13.79) 16(29.09) 0.39 (0.15, 1.00) 0.047 Urinary Fistula 4 (6.90) 11 (20.00) 0.30 (0.09, 0.99) 0.041 Urethral Stricture 4 (6.90) 2 (3.64) 1.95 (0.27, 22.43) 0.680 Glans fissure 0 (0.00) 3 (5.45) - - Table 2. Comparison of complications between the two groups. Satisfaction score Research Group Control Group Wilcoxon P Pre-operation 10.0 (8.0,11.0) 10.0 (9.0,11.0) 1621.5 0.879 32 weeks after operation 24.5 (23.3,25.0) 23.0 (20.5,24.0) 2417 < 0.001 Difference 14.0 (13.0,16.0) 13 (11.0,14.5) 2219.5 < 0.001 Table 4. Comparison of patients' satisfaction between the two groups. TIP with corpus covernusum covering method-Ji et al. Vol 20 No 3 May-June 2023 164 tinuous bucks fascia, and excessive dissociation dam- ages the blood supply, resulting in a high incidence of urinary fistula. In this study, the overall incidence of urinary fistula in the study group and the control group were 6.9% and 20% respectively, with a statistical- ly significant difference. It may be related to the way that we use "from far to near" to dissociate the corpus spongiosum and its successive Buck's fascia together. On the one hand, we can avoid excessive dissociation of the dysplastic cavernous body to damage its blood supply; on the other hand, because the blood supply of the corpus spongiosum moves from the proximal to the distal, this method is more in line with its blood supply direction, which can minimize the damage to the blood supply, and at the same time, we can restore the original anatomical structure as much as possible, Reduce the incidence of urinary fistula, especially at the coronary sulcus (P = 0.015). However, in this study, it was found that the incidence of urethral stricture in the study group was slightly higher than that in the control group, which may be related to the increased amount of tissue on the surface of the new urethra after cavernous body cover- age, resulting in urethral stricture. However, the num- ber of cases in this group is small, and more samples are needed for further analysis. At the same time, during the operation, we found that after the free anatomy of the poorly developed corpus spongiosum in most pa- tients, its length is limited, and it can't cover all the new urethra, but only the coronal sulcus, which only increas- es the amount of tissue in the coronal sulcus. This may be related to the lower incidence of urinary fistula in the coronal sulcus in this experiment than in the control group (the incidence of urinary fistula in the coronal sulcus in the study group is 1.72%, and 14.55% in the control group). In the surgical satisfaction survey, there was no differ- ence between the two groups in preoperative satisfac- tion, but the satisfaction score of the study group was higher than that of the control group 32 weeks after surgery, with a statistically significant difference (P < 0.001). During the operation, we routinely dissociate the two wings of the glans, trim the redundant tissues of the two wings of the glans, so as to fully "reduce the volume" of the glans, make the glans wrap around the new urethra without tension, and conduct parallel ten- sion free suture, in order to reduce the incidence of glans cracking after the operation, and obtain a more similar appearance to the normal glans, so using this operation can obtain better penile function and appearance. How- ever, Ceccarelli believed that the short-term evaluation results could not reflect the impact of surgery on life and sexual psychology in adolescence and adulthood, so long-term follow-up and intervention were needed. (14) Murat Gul believed that the long-term follow-up co- operation rate of most patients who received early sur- gical treatment was low.(15) Long term follow-up data are also lacking for this surgical method. In addition, this study is a single center case study, and there may be selection bias in sample selection. As an exploratory study, the total number of samples in this study is 113, which may lead to deviation in data analysis results due to the small number of patients. There are few variables collected in this study, and there may be confounding factors that are not observed. CONCLUSIONS To sum up, our surgical method of covering the new urethra with free dysplastic corpus spongiosum and its continuous Buck's fascia can reduce the damage to the blood supply of the dysplastic cavernous body on the one hand, and on the other hand, while restoring the original anatomical structure, it can maintain a good blood supply of the covering material, and it is conven- ient to obtain materials, which effectively reduces the incidence of urinary fistula at the coronary sulcus of distal hypospadias, At the same time, the appearance of the repaired penis is more similar to that of the normal penis, which is easier to be recognized by patients and their families. However, long-term follow-up is needed to understand the impact of surgery on the life and sex- ual psychology of patients in adulthood. ACKNOWLEDGMENTS This research is supported by National Natural Sci- ence Foundation of China (82171587). We thank An- gela Morben, DVM, ELS, from Liwen Bianji (Edanz) (www.liwenbianji.cn), for editing the English text of a draft of this manuscript. CONFLICT OF INTEREST All authors acknowledge that there is no conflict of in- terest. REFERENCES 1. Yuehua Li, Meng Mao, Li Dai, et al. Time trends and geographic variations in the prevalence of hypospadias in China. Birth Defects Res A Clin Mol Teratol. 2012; 94: 36- 41. 2. Snodgrass W. Tubularized, incised plate urethroplasty for distal hypospadias. J Urology. 1994; 151: 464-5. 3. K L M Pfistermuller, A J McArdle, P M Cuckow. Meta-analysis of complication rates of the tubularized incised plate (TIP) repair. J Pediatr Urol. 2015; 11: 54-9. 4. Warren Snodgrass, Gwen Grimsby, Nicol Corbin Bush. Coronal fistula repair under the glans without reoperative hypospadias glansplasty or urinary diversion. J Pediatr Urol. 2015; 11: 39. e1-4. 5. Marjan Joodi, Forouzan Amerizadeh, Seyed Mahdi Hassanian, et al. The genetic factors contributing to hypospadias and their clinical utility in its diagnosis. J Cell Physiol. 2019; 234:5519-5523. 6. Salim Bilici 1, Tamer Sekmenli, Mustafa Research Group N (%) Control Group N (%) OR and 95%CI P Fistula of penis 3 (5.17) 3 (5.45) 0.95 (0.12, 7.39) 0.947 Coronal sulcus fistula 1 (1.72) 8 (14.55) 0.10 (0.01, 0.83) 0.015 Table 3. Comparison of the location of urinary fistula between the two groups. TIP with corpus covernusum covering method-Ji et al. Pediatric Urology 165 Gunes, Ilhan Gecit, Vedat Bakan, Daghan Isik. Comparison of dartos flap and dartos flap plus spongioplasty to prevent the formation of fistulae in the Snodgrass technique. Int Urol Nephrol. 2011; 43: 943-8. 7. Xu Haihua, Xu Guodong, Zhang Fuyi, Chen Ziying, Wang Xiaojia. Application of multiple urethral with lateral fascia plate and dorsal pedicled transfer fascia flap during Snodgrass operation. Chin J Pediatr Surg. 2021; 42: 114- 117 8. E B Yerkes, M C Adams, D A Miller, J C Pope 4th, R C Rink, J W Brock 3rd. Y-to-I wrap: use of the distal spongiosum for hypospadias repair. J Urol. 2000; 163:1536-8. 9. H Dodat, J-L Landry, C Szwarc, S Culem, F-J Murat, R Dubois. Spongioplasty and separation of the corpora cavernosa for hypospadias repair. BJU Int. 2003; 91:528-31. 10. Amilal Bhat, Karamveer Sabharwal, Mahakshit Bhat, Ramakishan Saran, Manish Singla, Vinay Kumar. Outcome of tubularized incised plate urethroplasty with spongioplasty alone as additional tissue cover: A prospective study. Indian JUrol. 2014; 30:392-7. 11. Ashraf T Hafez, Tamer Helmy. Tubularized Incised Plate Repair for Penoscrotal Hypospadias: Role of Surgeon’s Experience. Urology. 2012; 79: 425-7. 12. Bao Xingqi, Study on abnormal development of corpus spongiosum in patients with hypospadias. Shanghai: Children's Hospital Affiliated to Shanghai Jiaotong University. 2019 13. Yutaro Hayashi, Kentaro Mizuno, Yoshinobu Moritoki, et al. Can Spongioplasty Prevent Fistula Formation and Correct Penile Curvature in TIP Urethroplasty for Hypospadias? Urology. 2013; 81:1330-5. 14. Pier Luca Ceccarelli, Laura Lucaccioni, Francesca Poluzzi , et al. Hypospadias: clinical approach, surgical technique and long-term outcome. BMC Pediatr. 2021; 21:523. 15. Murat Gul, Simone Hildorf, Mesrur Selcuk Silay. Sexual functions and fertility outcomes after hypospadias repair. Int J Impot Res. 2021; 33:149-163. TIP with corpus covernusum covering method-Ji et al. Vol 20 No 3 May-June 2023 166