Congenital penile curvature deformity is often associated with hypospadias, but it can also occur in those with orthotropic urethral opening, called simple penile curvature deformity, which accounts for about 4-10% of the cases of curvature deformity. The penis can be bent ventrally (inferior curvature), dorsally (superior curvature) and laterally, of which the main cases are inferior curvature.
I. Etiology
Young (1937) proposed that penile curvature is caused by congenital short urethra and can be corrected by transection of the urethral plate, while Devine et al. (1973) suggested that the cause of curvature is due to abnormal development of the fascial tissue around the urethra, and that there are few cases where the urethral plate really needs to be cut. In recent years, more physicians have recognized that asymmetry of the corpus cavernosum is also an important cause of penile curvature. The earlier belief that penile curvature was primarily due to abnormal urethral development has been widely questioned.
Anatomical and embryological studies have found that during normal male embryonic development, the penis is curved (inferiorly curved) early in life and straightens at about 16 weeks of gestation; if this process is affected, the curvature may be fixed and manifest as a curved penis deformity after birth. The abnormal process may involve some sex hormones, growth factors and sex hormone receptor abnormalities.
Second, the type of current bending etiology will be divided into four types of simple penile curvature.
1, skin curvature. If the penis is separated from the sleeve to perform artificial erection, the penis has been straightened, then the skin bending. This type is the lightest degree of bending, correction effect is satisfactory.
2, fascial bending. If the artificial erection after the condom is still bent, there is dense fibrous tissue around the urethra, the penis straightened after excision, is fascial, Buck fascia and meatus development abnormalities, fiber contracture caused. Treatment of this type requires full excision of the fibrous tissue around the urethra.
3. Asymmetric curvature of the corpus cavernosum. The urethral corpus cavernosum and urethra are normal in length, but the length of the corpus cavernosum is asymmetrical on the dorso-ventral side or both sides resulting in bending. This type of medium and heavy cases are more difficult to deal with, and there are more postoperative complications.
4, urethral curvature. Short urethra, fibrous urethra, or a thin mucosal urethra, resulting in penile curvature. This type of curvature should be handled according to the urethral hypospadias, need to remove the dysplastic urethra and reconstructed, such as urethral structure is good, can be cut off after the reconstruction of the shortage of part of the urethra.
In the four types, caused by urethral dysplasia is less, less than 10% of cases of simple penile curvature, the proportion of the first three types is similar.
Classification according to the severity of bending: the angle of penile bending is measured in the erect state.
1, light: bend less than 30 degrees.
2.Medium: the bend is between 30-45 degrees.
3.Heavy: bending greater than 45 degrees.
Most physicians believe that curvature greater than 30 degrees requires active surgical correction.
Diagnosis
Penile curvature can be diagnosed by visual examination, but the degree of curvature and the cause often need to be clear during surgery. Before surgery, we should observe the situation when the penis is erect, and apply urethra or urethral probe to check whether the urethra is dysplastic, as well as the relationship between the ventral penile skin and urethra.
IV. Treatment
Most congenital penile curvature will not improve significantly with the patient’s physical development, and obvious symptoms such as painful erection and inability to complete sexual life will appear after puberty due to the influence of sex hormones and the emergence of sexual activity, thus requiring surgical correction.
(i) Indications for surgery.
1.Bending more than 30 degrees.
2, accompanied by obvious symptoms, such as painful erection, inability to complete sexual life, etc.
3, the patient’s spiritual and psychological requirements.
(B) surgical procedures
Intraoperatively, an artificial erection test (induced by intracavernosal injection of opium poppy, prostaglandin E1 or saline) should be performed after the cuffed penile release, which is an important step for further assessment of the clinical type. Depending on the situation, several manual erections are sometimes required to accurately determine the type of penile curvature and to treat it accordingly.
If the penile skin cuff-like free to the proximal side of the penile scrotal junction area after erectile testing shows that the bend has been corrected, it should be considered a cutaneous bend. If there is still a mild residual bend, the fibrous tissue around the urethra should be completely excised and loosened to see if it belongs to the second type. If there is still a persistent curvature deformity with artificial erection again and it is not related to urethral length or dysplasia, it should be treated as disproportionate development of penile corpus cavernosum and white membrane.
Corrective surgery for penile curvature may be performed on the dorsal or ventral side of the penis, and the site of correction and the method used should be determined according to the development of the penis and the severity of the curvature. For severe curvature, especially those who are considered to have short urethra, it is often necessary to reconstruct the urethra at the same time to achieve success.
(C) surgical methods.
1, Nesbit surgery is more widely used. It is used for cases with asymmetric cavernous body (dorsal side is longer than ventral side). In the early stage, only the dorsal folded suture of the apex of the bend was made without incision or excision of the leukocutaneous tissue.
2, the white membrane fold (TAP) is widely used, mainly for infants and adolescents with asymmetrical cavernous body cases. After it is clear that the bending is caused by cavernous asymmetry, Buck’s fascia is separated and lifted next to the dorsal midline at the apex of the bend (2 and 10 o’clock) to avoid manipulation of the neurovascular bundle, and two parallel transverse incisions (approximately 8 mm long and 4-6 mm apart) are made on each side of the leukoplast, and the anterior and posterior edges of the four incision margins are sutured together (the leukoplast is embedded and the knot is buried).
3. The dorsal midline fold is a newly developed procedure.
There are three main reasons that have contributed to the application of this procedure.
(1) Recent anatomical studies of the penis have revealed that the nerves are distributed in a reticular pattern on the surface of the tunica albuginea between points 1 and 5 and between points 7 and 11, and that the nerve-free zone is at point 12, the dorsal midline, and that the thickness of the tunica albuginea is greatest there, making it suitable for tunica albuginea folding.
(2) Clinical experience shows that it is almost impossible to separate and lift Buck’s fascia on both sides of the midline without damaging the nerve.
(3) A high percentage of ED occurs in the long-term follow-up cases of paramedian leuko-fold surgery.
Parallel longitudinal sutures are made on both sides of the deep dorsal penile vein in the dorsal 12-point area of the corpus cavernosum, and multi-point suture folding is possible in case of longer curved segments, or thicker developing posterior penis. This procedure can correct most of the non-skin-fascial penile curvature.
4.Cavernous body rotation is often used in heavy bending cases with hypospadias. After freeing the urethral plate, the white membrane of the corpus cavernosum is incised longitudinally in the ventral midline and sutured on both sides of the corpus cavernosum under the dorsal Buck’s fascia (under the neurovascular bundle), and the corpus cavernosum is rotated dorsally to correct the hypospadias.
5.Penile splitting in the treatment of supraurethral cleft, the penile splitting method has been applied more often in recent years, and some physicians also apply this method to heavy hypospadias cases with hypospadias. The operation scope is large, easy to damage the neurovascular penis, the operator’s requirements are higher, and it is more difficult to promote.
6, cavernous patch white membrane folding surgery with a certain degree of penile shortening, so for heavy bending and penile short cases, more physicians believe that the cavernous patch should be made to retain sufficient penile length. This procedure is mainly used in cases of heavy penile curvature (often with hypospadias). The commonly used transplantation sheets include white membrane sheet (taking the convex side of the white membrane and transplanting it on the concave side), dermis sheet, sphincter sheet, vein sheet, dura sheet, synthetic material sheet, etc. In recent years, due to the development of tissue engineering technology, tissue engineering materials such as submucosa of small intestine are considered to be promising materials.
7, other surgical complications of surgery is mainly residual bending, heavy bending after surgery residual bending incidence is relatively high. Residual bending often occurs for reasons related to the operator’s inaccurate judgment of the cause and degree of bending, according to the aforementioned surgical procedures carefully examine the cause of bending, the selection of the corresponding surgical correction, and timely application of artificial erection test to understand the correction of bending, can often avoid the occurrence of such cases. If significant residual bending occurs and there is significant dysfunction, the procedure may be repeated in a manner similar to that of the initial treatment.
Urethral skin fistulas may also occur after penile curvature surgery and are associated with concurrent urethral reconstruction. Sometimes, the surgeon does not recognize that the bend is caused by urethral dysplasia and does not perform urethral reconstruction, which is also an important cause of urinary fistula after penile bend correction. The management of this type of condition is similar to the management of urinary fistula after hypospadias.
Most cases of penile curvature function well after surgery, while a few may develop erectile dysfunction. It is generally believed that postoperative erectile dysfunction may be related to nerve injury, intracavernosal thrombosis, etc., and in some cases to psychological factors.