Comparison of the Outcomes of Preputial Buttonhole Flap Versus Byars Flap Techniques in Hypospadias Treatment

doi:10.21203/rs.3.rs-5215531/v1

Download PDF

Research Article

Comparison of the Outcomes of Preputial Buttonhole Flap Versus Byars Flap Techniques in Hypospadias Treatment

https://doi.org/10.21203/rs.3.rs-5215531/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

Background:

Hypospadias, a prevalent congenital anomaly, is characterized by the incomplete development of the urethral spongiosum and the ventral prepuce. The current standard of care for hypospadias not only targets the attainment of a functional penis, facilitating sexual intercourse and upright urination, but also emphasizes an aesthetically pleasing outcome. The surgical techniques for treating hypospadias are continually advancing.

Methods:

In this study, two distinct skin coverage techniques used in hypospadias repair were compared. The Snodgrass technique was used to repair all 40 cases included in our study. In half of the cases (n = 20), an inner preputial buttonhole flap was used for skin coverage. For the remaining cases, a Byars flap was employed as a waterproof layer. The minimum period of follow-up was six months. Finally, data related to the surgical outcomes and the patients’ demographic characteristics were collected and analyzed using SPSS software.

Results:

The average age of the patients in this study was 26.1 months (SD, 8.5). The results indicated that there was no significant difference between the preputial buttonhole flap and Byars flap techniques in the treatment of hypospadias, considering factors, such as urethral fistula, meatal stenosis, and the need for a repeat surgery postoperatively (P > 0.05).

Conclusions:

Our findings suggest that the preputial buttonhole flap technique may be more effective than the Byars flap surgery in neourethra coverage for preventing fistulas in distal hypospadias. However, to substantiate these findings, further studies with larger sample sizes are required.

Hypospadias

Buttonhole Flap

Byars Flap

Hypospadias is the most common congenital anomaly of the penis, in which the opening of the urethra is located on the ventral aspect of the penis, proximally to its normal position (1). The prevalence of this disease in Iran is estimated at 4 per 1000 live births (2). The optimal timeframe for surgery is typically 6–12 months, although some sources suggest that it can be performed up to 36 months (3).

In tubularized incised plate (TIP) urethroplasty, a U-shaped incision is made on the ventral aspect of the penis, flanking both sides of the urethral plate. This incision extends distally towards the urethral meatus. Subsequently, the two incision lines are converged and sutured, thereby constructing a new urethra. The Byars flap method, used in 95% of hypospadias cases, serves to cover the suture site at the tip. This technique involves making a midline incision in the prepuce, dividing it into two parts. Both parts are then moved to the ventral aspect of the penis and sutured into place.The distinction between our study and other research lies in our use of a ventral dartos flap, as opposed to dartos flaps without skin used in the referenced studies. In the Byars flap technique, the suture aligns with the suture from the TIP procedure, while in the buttonhole flap technique, there is no overlap. Theoretically, this suggests a higher likelihood of fistula formation in the Byars flap technique. In this method, the prepuce is manipulated, whereas in the buttonhole flap technique, the prepuce remains untouched. Consequently, if a patient experiences complications, such as postoperative fistula, the intact flap can be utilized on the ventral surface for repair in the buttonhole flap technique; this advantage is not present in the Byars flap surgery (4–8).

We conducted the present study to evaluate if the buttonhole flap technique could serve as a viable alternative to the conventional Byars flap method for reducing complications.

We aimed to examine the complications associated with the buttonhole flap and Byars flap techniques at Imam Reza Hospital in Ardabil, Iran, during 2020–2021.

This descriptive, analytical study was conducted in the form of case reports. The research population included all patients aged 12–36 months with hypospadias, who were referred to Imam Reza Hospital in Ardabil, Iran, for reconstructive surgery during 2020–2021. For sampling, we employed the total enumeration method. This ensured that all patients with hypospadias, who underwent reconstructive surgery using the preputial buttonhole flap and Byars flap techniques at Imam Reza Hospital during 2020–2021, were included in the study.

The study included a sample size of 40 individuals. During the specified period, 20 patients underwent surgery using the preputial buttonhole flap technique, while the remaining 20 patients were treated with the Byars flap method. The allocation was random. Data was collected from all hypospadias patients using a checklist during a six-month period following their reconstructive surgery at Imam Reza Hospital. The complications examined in this study included wound infection, penile rotation, fistula formation from the duct to the skin, and meatal stenosis. Figures (1–5) illustrates the button hole flap surgical technique.

Analytical methods, such as chi-square test, Fisher’s exact test, and Mann-Whitney test, were employed to describe the gathered data. The statistical analysis was performed using SPSS Version 21, with a P-value of less than 0.05 deemed statistically significant. All patient-related information remained confidential with the physician and the project manager. The study was conducted without disclosing the names of the patients. The ethics code for this study was IR.ARUMS.MEDICINE.REC.1401.093.

This study was conducted on 40 patients who underwent reconstructive surgery for hypospadias. The patients’ age ranged from 12 to 36 months, with an average age of 26.1 ± 8.5 months. According to their medical records, one patient had a history of cryptorchidism, while the others had no record of other diseases. The majority of the patients (n = 37) had distal hypospadias, while the remaining three had proximal hypospadias. The treatment for all three patients with proximal hypospadias involved the buttonhole flap technique.

Among 40 patients with hypospadias, 11 patients (27.5%) presented with meatal stenosis, while seven patients (17.5%) developed urethral fistula postoperatively. There were no instances of penile rotation or postoperative wound infection in any of the patients.

Regarding the treatment methods, 20 patients were treated with the Byars flap method. Four of these patients (20%) developed meatal stenosis, while five of them (25%) developed a urethral fistula to the skin. The remaining 20 patients were treated with the buttonhole flap technique. In this group, seven patients (35%) experienced meatal stenosis, while two patients (10%) developed a urethral fistula. Both patients who developed a urethral fistula had proximal hypospadias. Interestingly, none of the patients with distal hypospadias developed this complication following the buttonhole flap surgery. This indicates that the incidence of urethral fistula was higher following the Byars flap surgery compared to the buttonhole flap surgery. However, according to the Fisher’s exact test, this relationship was not statistically significant (P = 0.407).

The incidence-to-non-incidence ratio of fistula following surgery was higher in proximal hypospadias (2), compared to distal hypospadias (0.15). This relationship was found to be statistically significant (P = 0.02), as determined by the chi-square test. It means that fistula rate was so higher in proximal hypospadias repair. Based on the findings, the occurrence of meatal stenosis was higher following the buttonhole flap surgery (35%), compared to the Byars flap surgery (20%). However, the chi-square test indicated that the difference was not statistically significant (P = 0.288).

According to the present findings, the average age of patients who developed a urethral fistula postoperatively was 29 ± 6.8 months, which is higher than the average age of patients who did not develop a urethral fistula (18.7 ± 8.26 months). This difference was found to be statistically significant (P = 0.034), as determined by the Mann-Whitney test. It means that older patients have more post-op fistula. The findings also showed that the average age of patients who developed meatal stenosis postoperatively was (22.32 ± 8.8) months, which is higher than the average age of patients who did not develop meatal stenosis (19.81 ± 8.47) months. However, according to the Mann-Whitney test, this difference was not statistically significant (P = 0.55).

This study was undertaken to compare the complications associated with two surgical techniques used in the treatment of hypospadias: The preputial buttonhole flap and the Byars flap. The primary complication examined in this study was the occurrence of a urethral fistula. This is a common complication arising from the conventional surgical repair of hypospadias. Theoretically, the buttonhole flap method is associated with a lower likelihood of experiencing this complication.

An alternative method for covering the suture area in TIP is the buttonhole flap technique, which involves creating a hole in the prepuce and then moving it to the ventral aspect of the prepuce and suturing it. A study conducted in South Korea from 1996 to 2004 investigated the outcomes of TIP using the buttonhole flap technique for hypospadias repair. The findings revealed that the overall success rate of the buttonhole flap technique was 75%. The success rates for different types of hypospadias were as follows: 87% for glandular, 77% for coronal, 66% for midshaft, and 50% for penoscrotal types. Following the buttonhole flap operation, the extent of penile rotation was significantly less compared to the traditional method. The most frequent complication associated with the buttonhole flap technique was urethrocutaneous fistula. This technique showed a high rate of success, fewer complications, and better cosmetic outcomes across all hypospadias types. Importantly, it also significantly decreased the incidence of penile rotation (9).

Another study, conducted in Serbia from 1998 to 2005, which aimed to explore the use of the dorsal dartos flap in preventing fistula formation following TIP for hypospadias, reported successful results, with no fistula formation in any of the patients. The findings suggested that the dorsal dartos flap, which is moved towards the ventral aspect of the penis using the buttonhole technique, is an effective choice for preventing fistulas. Meatal stenosis was the most common complication. However, all cases of meatal stenosis were effectively managed through dilatation (10). Additionally, a study conducted in Germany during 2011–2014 examined the complications associated with the preputial buttonhole flap technique for anterior urethra reconstruction. The results showed that out of 41 patients with hypospadias who underwent the buttonhole flap procedure, urethrocutaneous fistula occurred in four cases (11). Moreover, in 2016, a study was carried out in Iraq to evaluate the effectiveness of the dorsal dartos flap technique in preventing fistula formation following the Snodgrass repair of distal hypospadias. Based on their findings, 34 individuals (97.14%) showed no signs of fistula formation. Only one patient (2.8%) developed a fistula. Meatal stenosis occurred in three patients, which is 8.5% of the total (12).

A systematic review and meta-analysis conducted by Wu et al. in China in 2020, evaluating the complications of non-proximal hypospadias following conventional surgery, found that a urethral fistula was the most common complication (13); this finding aligns with the results of the present study.

In our study, out of 20 patients treated with the buttonhole flap technique, seven patients (35%) developed meatal stenosis and two patients (10%) developed a urethral fistula. It is noteworthy that both patients who developed a urethral fistula had proximal hypospadias. Interestingly, none of the patients with distal hypospadias developed this complication following the buttonhole flap surgery.

Several studies, including those by Viseshsindh in Thailand in 2014 (14) and Snodgrass and Bush in 2016 (15), have demonstrated a higher incidence of urethral fistula following surgical repair in proximal hypospadias, compared to distal hypospadias. In our study, we found a higher ratio of fistula occurrence to non-occurrence postoperatively in proximal hypospadias (n = 2), compared to distal hypospadias (0.15); this relationship was statistically significant and aligned with the findings of the aforementioned studies.

In our study, we observed a higher incidence of urethral fistula following the Byars flap surgery compared to the buttonhole flap surgery; however, this difference was not statistically significant. Therefore, further studies with larger sample sizes are needed to confirm these results.

On the other hand, when considering only distal hypospadias, five out of 20 cases developed a urethral fistula to the skin following the binary flap surgery. In contrast, none of the 17 cases treated with the buttonhole flap surgery developed this complication. This difference was found to be statistically significant. The study concluded that the buttonhole flap method is more effective than the Byars flap method in preventing fistula in distal hypospadias. However, due to the absence of proximal hypospadias cases treated with the Byars flap method, which is a limitation of the current research, it is not possible to compare the incidence of fistula following proximal hypospadias between the buttonhole and Byars flap methods.

In the present study, we observed a higher incidence of meatal stenosis following the buttonhole flap surgery (n = 7) as compared to the binary flap surgery (n = 4); however, this difference was not statistically significant. This finding suggests that a potential drawback of the buttonhole flap technique could be a higher rate of meatal stenosis compared to the binary flap technique. To confirm this observation, further studies with larger sample sizes are required.

Our results indicated that the mean age of patients who experienced urinary tract fistulas postoperatively was significantly higher than that of patients who did not develop these complications. Similarly, the mean age of patients who developed meatal stenosis following surgery was higher in comparison to those who did not exhibit meatal stenosis postoperatively. It can be concluded that a delay in a child’s surgery and an increase in the child’s age at the time of the initial surgery may lead to a higher frequency of urethral fistula and possibly meatal stenosis. To mitigate the impact of age on the study results, both the binary flap and buttonhole flap groups were randomly selected among children aged 12–36 months. The mean age of the Byars flap group was 24 months, while the mean age of the buttonhole flap group was 18 months.

Another study conducted by Snyder et al. in 2005 aimed to examine the complications of hypospadias in 10–15% of restorations and to identify the factors influencing the outcomes of restorations. Their findings indicated that the success of restoration is not dependent on the patient’s age or the time interval between the initial restoration and the subsequent operation (16). Additionally, the patient’s age at the time of the initial surgery did not correlate with the complication rate. Nevertheless, the results of these studies are not consistent with the findings of our research.

Low study sample size and short follow up time might be limitations to make any outstanding result.

The comparison of the preputial buttonhole flap technique with the Byars flap method for treating hypospadias showed no significant difference in terms of urethral fistula and meatal stenosis. For the distal type of hypospadias, the incidence of urethral fistula was significantly lower following the buttonhole flap surgery, compared to the Byars flap technique. In contrast, the incidence of fistula following surgery was significantly higher in proximal hypospadias, compared to distal hypospadias. Furthermore, patients who developed fistulas postoperatively were significantly older at the time of surgery compared to those who did not develop this condition.

Clinical trial Number:Not applicable

Ethics: IR.ARUMS.MEDICINE.REC.1401.093.

Consent: All patients parents have consent for publication of their data article

Availability of data: All data is available

Competing interests: Not applicable

Funding: Not applicable

Authors contributions : Hamed Mohseni Rad has conception and design of the work;

Farzin Valizade is involved in the acquisition, analysis,

Navid Amirkhani is involved in interpretation of data.

All authors have approved the submitted version

All authors have agreed both to be personally accountable for the author's own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature.

Leung AK, Robson WL. Hypospadias: An update. Asian J Androl. 2007;9(1):16–22. https://doi.org/10.1111/j.1745-7262.2007.00243.x. [PubMed ID:17187155].
Mohammadzadeh A, Farhat A, Esmaieli H, Shiranzaei S. Prevalence and risk factors of hypospadias in a private hospital in northeast Iran. Iran J Pediatr. 2011;21(4):497–501. [PubMed ID:23056838].
Manzoni G, Bracka A, Palminteri E, Marrocco G, whom?. BJU Int. 2004;94(8):1188–95. https://doi.org/10.1046/j.1464-410x.2004.05128.x. [PubMed ID:15613162].
Abouzeid AA. Modified Byars' flaps for securing skin closure in proximal and mid-penile hypospadias. Ther Adv Urol. 2011;3(6):251–6. https://doi.org/10.1177/1756287211427722. [PubMed ID:22164194]. [PubMed Central ID:PMC3229250].
Basavaraju M, Balaji DK. Choosing an ideal vascular cover for Snodgrass repair. Urol Ann. 2017;9(4):348–52. https://doi.org/10.4103/UA.UA_90_17. [PubMed ID:29118537]. [PubMed Central ID:PMC5656960].
Blanc T, Peycelon M, Siddiqui M, Muller C, Paye-Jaouen A, El-Ghoneimi A. Double-face preputial island flap revisited: Is it a reliable one-stage repair for severe hypospadias? World J Urol. 2021;39(5):1613–24. https://doi.org/10.1007/s00345-020-03324-7. [PubMed ID:32601982].
Turkyilmaz Z, Karabulut R, Atan A, Sonmez K. Redo hypospadias repair: Comparison of three different methods. Urol Int. 2020;104(5–6):391–5. https://doi.org/10.1159/000504947. [PubMed ID:32023621].
Tessier B, Sfar S, Garnier S, Coffy A, Borrego P, Gaspari L, et al. A cover flap reduces the rate of fistula after urethroplasty whatever the severity of hypospadias. World J Urol. 2021;39(7):2691–5. https://doi.org/10.1007/s00345-020-03489-1. [PubMed ID:33108479].
JANG S-W, KIM Y-G. [Results of tubularized incised plate (TIP) urethroplasty with button hole flap in hypospadias repair]. Korean J Urol. 2005:281-7. Portugues.
Djordjevic ML, Perovic SV, Slavkovic Z, Djakovic N. Longitudinal dorsal dartos flap for prevention of fistula after a Snodgrass hypospadias procedure. Eur Urol. 2006;50(1):53–7. https://doi.org/10.1016/j.eururo.2006.04.014. [PubMed ID:16707207].
Ludwikowski B, Gonzalez R. Total preputial flap: A reliable and versatile technique for urethral and penile reconstruction. Front Pead. 2014;2:43. https://doi.org/10.3389/fped.2014.00043.
Shakir F. Evaluation of the use of dorsal dartos flap for the prevention of fistula after snodgrass repair of hypospadias. Basrah J Surg. 2016;22:52–6. https://doi.org/10.33762/bsurg.2016.116613.
Wu Y, Wang J, Zhao T, Wei Y, Han L, Liu X, et al. Complications following primary repair of non-proximal hypospadias in children: A systematic review and meta-analysis. Front Pediatr. 2020;8:579364. https://doi.org/10.3389/fped.2020.579364. [PubMed ID:33363061]. [PubMed Central ID:PMC7756017].
Viseshsindh W. Factors affecting results of hypospadias repair: Single technique and surgeon. J Med Assoc Thai. 2014;97(7):694–8.
Snodgrass W, Bush N. TIP hypospadias repair: A pediatric urology indicator operation. J Pediatr Urol. 2016;12(1):11–8. https://doi.org/10.1016/j.jpurol.2015.08.016. [PubMed ID:26515776].
Snyder CL, Evangelidis A, Hansen G, St Peter SD, Ostlie DJ, Gatti JM, et al. Management of complications after hypospadias repair. Urology. 2005;65(4):782–5. https://doi.org/10.1016/j.urology.2004.11.037. eng. [PubMed ID:15833528].

No competing interests reported.

Download PDF

Editorial decision: Revision requested
28 Oct, 2024
Editor assigned by journal
28 Oct, 2024
Submission checks completed at journal
12 Oct, 2024
First submitted to journal
07 Oct, 2024

You are reading this latest preprint version

Comparison of the Outcomes of Preputial Buttonhole Flap Versus Byars Flap Techniques in Hypospadias Treatment

Status:

Version 1

Abstract

Background:

Methods:

Results:

Conclusions:

Figures

1. Background

2. Objectives

3. Methods

4. Results

5. Discussion

Conclusion

Declarations

References

Additional Declarations

Status:

Version 1