Normally, Mullerian tube inhibitor (MIF) prevents the development of the female reproductive system in embryos around the 10th week of development. When the secretion of MIF is insufficient or the urogenital sinus is not fully developed in a way that allows for the formation of male reproductive organs, the Mullerian tube can degenerate incompletely and form a cystic dilatation connected to the prostatic urethra, forming a prostatic sac, or cyst. Cysts are small and asymptomatic and are often found in physical examination. They can also be secondary to infection, stones or obstruction. Additionally, urinary tract infections, epididymitis and scrotal abscesses can occur repeatedly [6], and there are even reports of malignant transformation of prostate cysts [7]. About 90% of prostatic sac cases also display hypospadias or ambiguous external genitalia [8].The end of the vas deferens (ejaculatory duct), normally opening in the verumontanum, can open into the cyst. According to Monfort [9], in 4 out of 5 cases, the vas deferens entered the cyst. Ritchey et al. [10] explained that the verumontanum originating from the urogenital sinus were affected due to the abnormality of the urogenital sinus and the formation of the prostatic sac.Which the ejaculatory duct and vas deferens implant ectopically. Postoperative treatment of hypospadias is often accompanied by urethral stricture up to 7–12%[11–13]. With the increase of urethral pressure after urethroplasty, epididymitis can often occur after undergoing surgery to remedy hypospadias with a prostatic sac.
Hypospadias complicated with prostatic sac is often the result of intraoperative catheterization difficulties or complications after urethroplasty before the discovery of prostatic sac, and few preoperative diagnoses are confirmed. However, if the size and location of cysts are not known before operation, it can cause difficulties during the operation and affect the success of the operation. Therefore, it is necessary to determine whether there is a prostatic sac before operation for hypospadias, especially for severe hypospadias. Shima et al. [14] reported that prostatic sacs occurred in 13.9% (21/151) of penile-scrotal and perineal hypospadias patients. Therefore, the incidence of severe hypospadias, especially perineal hypospadias with prostatic sac is high, and relevant imaging examinations should be performed before operating. Most retrograde and excretory urethrographies can confirm the presence of a prostatic sac.
In order to for the normal penis shape to develop after operation, the prevalent hypospadias surgery generally places the external urethral orifice in the front of the glans, surrounded by the glans cavernous body. The advantage of this external urethral orifice is that there is a cavernous body in the urethral orifice. The pressure of the contraction of the cavernous body is conducive to straightening the urethra and making the distance the urine travels longer.However,the disadvantage is that it increases the pressure on the urethra during micturition, which is related to the poor compliance of the external urethral orifice in the glans. Compliance means the tendency of an organ to resist deformation by a force[15]; obviously, encapsulation of the external orifice of the urethra by the glans cavernosum reduces urethral compliance. Therefore, hypospadias patients with prostatic sac, it can easily cause epididymitis. Furthermore, the new external urethral orifice protruded from the glans tends to form scar stricture or even atresia, and the proportion of urethral orifice stricture accounts for about 50% of the total urethral stricture after hypospadias surgery[16]. This stricture can also cause increased urethral pressure. In patients with hypospadias complicated with prostatic sac, urine easily flows back to the testis, causing epididymitis attacks. For these reasons, we advocate that the external urethral orifice should be placed in the coronal sulcus in patients with hypospadias complicated with prostatic sac. When this method was tried in our hospital, for 3 patients in group A, the external orifice of urethra was placed near the coronal sulcus instead of passing through the glans cavernosum in their initial operation, and no epididymitis occurred. 4 patients in group B suffered from recurrent epididymitis after their initial operation. We performed an second operation in which the urethra was dilated and the external orifice of the urethra was torn to the coronal sulcus. After that, epididymitis did not recur and satisfactory clinical results were achieved. However, the opening of the coronal sulcus has clear drawbacks. First, there is a significant difference between the appearance of the coronal sulcus and the normal penis, which may affect the psychological health and sexual functions of the patients. Second, the urination is sprinkled during passage, which affects the urination process. However, we believe that the advantage of coronal sulcus opening is greater than the disadvantage of infertility caused by repeated painful attacks of epididymitis and eventual surgical removal of the prostate sac and blockage of the vas deferens.