Analysis of associated scrotal anomalies in boys with hypospadias

Introduction

Hypospadias is the most common congenital anomaly of the penis characterized by the abnormal ventral position of usingthe urethral opening and associated penile curvature.^1,2 Etiology of hypospadias is thought to be a combination of genetic defects and environmental factors that affect the developing male external genitalia.^3–5 Disturbance of scrotal development can also occur at that time.⁶

Congenital scrotal anomalies are rare clinical findings. The spectrum of these anomalies has been described, such as penoscrotal transposition (PST), bifid scrotum (BS), accessory scrotum, scrotal agenesis, hypoplasia, scrotoschisis, and scrotal calcinosis. Although rare, scrotal anomalies are often found together with hypospadias.^5,7–9 Currently, studies discussing scrotal anomalies in hypospadias are limited and mostly reported through case reports. A study by Fahmi et al discusses scrotal position disorders in children comprehensively but not specifically for children with hypospadias.¹⁰ Spectrum and severity of scrotal anomalies are thought to be associated with the severity of hypospadias. This study aims to analyze associated scrotal anomalies in children with hypospadias who were treated in our institution.

Methods

Results

During the study period, there were 244 hypospadias patients. Four of them were excluded due to incomplete data in medical records. A total of 240 hypospadias patients were included in this study, with a median age of 5.6 years (range 0.8 – 18 years old). Most patients had severe hypospadias. Associated scrotal anomalies were found in 63.3% of patients; the spectrum of this anomaly is described in Table 1. Scrotoplasty was performed in 81,5% cases with scrotal anomalies.

Incidence of scrotal anomaly was higher in patients with severe hypospadias (75%) compared to mild cases (75% vs 36.1%; p<0.001), as described in Table 2. Severe hypospadias had a significantly higher prevalence of scrotal anomaly compared to those with mild hypospadias (PR=2.08 (95% CI: 1.51 – 2.86)).

Most patients with mild hypospadias (80.6%) did not have PST and SB. Patients with severe hypospadias had a more severe PST, especially in bilateral minor and major forms compared to patients with mild cases (p<0.001) (Table 3). Patients with severe hypospadias were significantly associated with severe and partial types of SB (p<0.001) (Table 4).

Patients with a more severe PST tend to have a more severe SB, compared to patients with milder type of PST. On the contrary, patients with minor PST tend to have a milder BS or even no BS (p<0.001) (Table 5).

Discussion

Most of our patients were presented at an older age compared to the other studies.^13–15 Hypospadias can be corrected at any age but mostly recommended at 6 to 18 months. Scrotal abnormalities which may be associated with hypospadias, are usually corrected simultaneously.^5,16,17 The late presentation may be due to various factors, such as socioeconomic problems, or difficulties in accessing our provincial hospital that covers a wide geographic area. We also found that severe hypospadias was more common than the mild type. This is in line with previous study at the same hospital, where the characteristics of our hypospadias patients had a worse penile biometry profile with a more severe degree of hypospadias.¹⁸

Hypospadias occurs due to cessation of penile development in the fetus. This process is divided into 2 phases: the hormone-independent phase (5th – 8th week of pregnancy) where the development of the genital tubercle occurs; and the hormone-dependent phase (8th – 12th week of pregnancy) where lengthening of the genital tubercle, fusion of the urethral folds to the midline to form the penile urethra, and development of the scrotum occur.² Scrotal development begin early in the fifth week of gestation. A pair of swellings called urogenital folds develops on either side of the urogenital plate. Labioscrotal swellings, then appear on either side of the urethral folds. Starting in the fourth month of gestation, with the effects of dihydrotestosterone, labioscrotal folds fuse at the midline to form the scrotum.⁶ Depending on the severity of the disorder, mild and severe hypospadias as well as scrotal anomalies can occur.

We found a high incidence (63.3%) of scrotal anomalies in boys with hypospadias, with PST and BS as the most common spectrum. PST and BS were found together in 45.3% of all cases with scrotal anomalies. Scrotal development and urethral localization both take place during the first trimester.¹⁹ PST and BS arise from abnormal or arrested migration and fusion of labioscrotal swellings due to poor response to androgens.^10,19,20

In this study, both PST and BS occurred more often in severe hypospadias (p<0.001). Contrary, 80.6% of patients with mild hypospadias had no PST or BS. It is consistent with findings from other studies where PST is usually accompanied by proximal hypospadias.^10,21,22 A study by Swartz et al. also stated that 86% of patients with BS had severe hypospadias, but they did not classify the severity of BS.¹⁹ The greater proportion of PST and BS in severe hypospadias indicated that severe hypoplasia of the ventral penis and proximal urethral opening may influence the process of caudal migration and fusion of the scrotum. Apart from that, severe androgen defects also definitely have an influence.

All types of PST, especially bilateral minor and incomplete major types were more often found in severe hypospadias compared to the mild one (p<0.001). However, the most severe form which is complete major PST was found only in 7,1% of severe hypospadias cases. Complete major PST is a rare heterogeneous condition that result from abnormal genital tubercle development around the 6th week of gestation.^7,23 In this study, the lower incidence of complete major PST reflects the small number of hypospadias patients who might have abnormal penile development starting at non-hormonal phase when the development of genital tubercle occurred. Severe form of BS was also found in the majority of severe hypospadias cases in this study. Further analysis showed that severe PST was associated with higher degree of BS. This supports the interrelated processes of scrotal migration and fusion.

We found only 3 patients with scrotal hypoplasia. The etiology of scrotal hypoplasia is multifactorial, which are localised androgen insensitivity, localised 5a-reductase deficiency, and failure of formation of the labioscrotal fold. It is also usually associated with undescended testes. In this study, two patients had unilateral scrotal hypoplasia with ipsilateral undescended testes (UDT). This number is very small considering that the etiology of hypospadias is also caused by androgen defects and this disorder is often accompanied by UDT. This may be due to the assessment of scrotal hypoplasia that are more challenging in patients with hypospadias because of the frequent PST and BS that accompany it.

fPST necessitates a staged surgical repair for physiological and psychological reasons if associated with severe hypospadias.¹⁰ The goal of the surgery in PST is to achieve normal anatomic position of the penis and scrotum with concurrent correction of the severe hypospadias. In our institution, scrotoplasty was performed in 35,4% of hypospadias cases with associated PST. However, the type of PST indicated for scrotoplasty, timing of procedure (whether scrotoplasty performed with the first or subsequent stages of hypospadias repair), stages needed, and the techniques used were still varied among paediatrics surgeons in our institution. Scrotal procedure has been described for correction of PST, in which two halves of scrotum are mobilized as advancement flaps with relocation of scrotum caudal to the penis.^24,25 Mori-Ikoma, Glenn Anderson, and buttonhole technique were among the most common procedures used in our centre. Inverted omega skin incision at the scrotal apex and the base of penis is used in Mori-Ikoma technique, closure of the flaps is in the form of zeta. In Glenn Anderson technique both halves of scrotum are fully mobilized as rotational advancement flaps, relocating the scrotal compartment to a normal dependent position, and constructing the neourethra during the same operation. In buttonhole technique, the degloved penis is brought out to the new dorsal site leaving the scrotum at caudal position. The transposed penis than delivered through a newly created window in the dartos tissue to achieve proper orientation with the shaft skin. In 12% of cases, we did scrotal fat mobilisation for PST repair without extensive scrotal skin roof incisions as in Mori-Ikoma and Glenn Anderson technique. Penoscrotal junction was divided, followed by mobilisation of the scrotal fat and penoscrotal skin flap caudally.

This study provides a thorough analysis of associated scrotal anomalies in children with hypospadias. However, it has some limitations. This is a retrospective study so that data collection was based on medical records, supported by clinical photos of the external genitalia of the patients. Although bias may occur, scrotal abnormalities should be easily assessed from clinical photographic data. We have not been able to comprehensively evaluate the scrotoplasty results due to the diversity of indications, techniques, timing, and performed by multiple surgeons.

Conclusions

Most hypospadias patients had associated scrotal anomaly, in which severe hypospadias was associated with the more severe type of PST and BS.

Ethical considerations

This study has Ethical approval from The Research Ethics Committee of Dr. Hasan Sadikin General Hospital Bandung, Indonesia on 28 February 2023 and the ethical approval number: LB.02.01/X/6/5/67/2023. The research has been performed following the Declaration of Helsinki.

Consent: All parents or guardians signed written informed consent to participate in this study.