Hypospadias is one of the most common congenital malformations of the pediatric genitourinary system. The incidence in our country is less than 0.1%. Modern studies have shown that the genital ganglion grows to form the penis under the action of dihydrotestosterone starting in the 10th week of embryonic development. The urogenital sinus (i.e. urethral plate) from the endoderm is guided by the urethral folds to extend to the apex of the glans to form the urethra, and the entire urethra, including the urethra of the glans, is formed by the fusion of the dorsal urethral plate to the ventral side, and this process is an open and continuous one. The fusion of the urethral plate is obstructed for various reasons, so that the urethra is formed at a certain stage and leads to hypospadias, and fibrosis of the spongy body around the urethra leads to hypospadias.
Etiology.
1, genetic factors.
(1) genetic mutations: such as androgen synthesis and action process-related genes, androgen receptor genes, sexual differentiation-related genes and other mutations.
(2) chromosomal aberrations: cytogenetic analysis of children with hypospadias in China revealed that the abnormal karyotype can be: 49, XXXXY, 45, XO, 46 , X, 46, XY, 47, XYY, 46 , XX, 46, XX, 46, XY, 46,X,_Y, 5ace/ 45, 46, XY, large Y, etc.
2. Environmental factors.
(1) Exogenous estrogens: Environmental estrogenic substances, including synthetic estrogens used as drugs, phytoestrogens derived from food, fungal estrogens in cereals, and estrogenic components in a large number of daily products and industrial pollutants, as well as pesticides, have gradually been found to interfere with the normal endocrine function of the body, acting on hormone synthesis, secretion, transport, site of action and metabolism, and affecting androgenic sex. The epidemic of hypospadias in China The epidemiological data of hypospadias in China also show that the incidence of hypospadias has increased significantly with the development of agriculture and industry in China, and is obviously concentrated in economically developed areas.
(2) Progesterone: The incidence of hypospadias in in vitro fertilized children exposed to exogenous progesterone during the eighth week in the mother is five times higher than that in normal controls. Exogenous progesterone is often used in the treatment of contraception and preterm abortion in China, which may increase the risk of fetal hypospadias, but its relationship with the increased incidence of hypospadias in China has not been systematically studied.
(3) Other factors: the mother’s history of spontaneous abortion before pregnancy, preeclampsia during pregnancy, flu with fever in early pregnancy, use of anti-infective and antipyretic drugs in mid-pregnancy, father’s occupational exposure to pesticides, and low birth weight of the fetus may increase the risk of fetal hypospadias. The relationship between the father’s fertility and the mother’s age and first birth and hypospadias are also risk factors of concern.
Treatment: Hypospadias is primarily treated surgically by straightening the penis and correcting the ectopic opening of the urethra to achieve near normal urination and appearance without affecting erectile function in adulthood. There are many surgical options for congenital hypospadias, and the selection of the appropriate surgical procedure is generally based on the degree of penile deformity and the location of the ectopic urethral opening after correction of the deformity, i.e., the suburethral cleft typology. At present, there are more than 300 types of hypospadias surgery reported at home and abroad, but there is not yet an accepted and satisfactory surgical method, and hypospadias surgery is constantly being improved and developed.
The criteria for healing after hypospadias repair are.
①The hypospadias is completely corrected, and the hypospadias of the head of the penis is often manifested as a bulbous penile head, which should also be corrected to restore its normal conical shape;
②The urethral opening is located at the tip of the penile head;
③ Satisfactory appearance of the penis, close to normal, able to stand and urinate, and able to have normal sexual life in adulthood.
At present, the following surgical methods are commonly used for hypospadias
1.Anterior displacement of the external urethral opening and penile headplasty
In 1981, Duekett first reported that the urethral orifice was moved forward and the head of the penis was shaped. Atala used free urethra and anterior displacement of the urethral orifice to treat hypospadias of the head, glans and corpora of the penis with hypospadias. This method of treating the coronal and subcoronal type of hypospadias is easy to perform, and complications such as urinary fistula and urethral stricture rarely occur. The surgical effect is good, and the postoperative appearance is perfect and basically similar to normal with few complications.
2.Urethral lengthening.
This method extends the urethra by freeing the anterior urethra and pushing it to the top of the glans. The formed urethra is covered by the glans and penile skin, the blood flow of the anterior urethra is wrapped in the white membrane and connected with the blood flow of the posterior urethra, and the white membrane of the urethral spongiosa is not damaged when freeing the urethra, which ensures the blood flow of the urethra. Because the longer the urethral release free, the greater the risk of blood flow obstruction at its distal end, so this method is suitable for coronal and penile corporal hypospadias; the extension length is appropriate for the urethra not to flatten and the cavernous body not to be ischemic, and the extension length is not more than 75px for children and 125px for adults.
3.Urethroplasty with vascular flap at the base of the urethra
In 1932, Mathieu reported that urethrotomy with basal vascular flap urethroplasty was widely used for anterior hypospadias without hypospadias where the coronal groove and urethral orifice are located in the anterior 1/3 of the penile body. The flap is lifted and flipped towards the glans, and the urethral plate or urethral groove of the glans distal to the urethra is sutured in a loose-leaf fashion to reconstruct the urethra. The new urethra is then covered with glans tissue.
4. Scrotal flap urethroplasty with tip.
(1) Scrotal longitudinal flap urethroplasty: It is suitable for those with suburethral cleft at the penile-scrotal junction and well-developed scrotum. The method is to preserve the longitudinal vascular plexus of the scrotum, form an axial flap with a vascular tip in the central part of the scrotum, and sew it into a tube to repair the urethra and complete the repair of hypospadias in one stage. The advantages are that the good blood supply of the skin tube is preserved, the success rate is high, the scrotal skin and endothelium are stretchable, the skin tube is made to be counter-attached to the white membrane of the penis, there is no tension, it does not affect blood flow, ensures the patency of the new urethra and normal erection of the penis, and the operation is simpler. In severe hypospadias with a long urethral defect, when a foreskin flap is not sufficient for repair, the combined application of a median scrotal tipped flap or in situ flap can achieve the purpose of one-stage repair, and failure of foreskin flap surgery or failure of other procedures can be applied as a second option. This procedure is one of the most commonly used procedures for the treatment of penile scrotal hypospadias.
(2) Arcuate combined flap urethroplasty of the penis and scrotum with tip: The principle of this procedure is based on the anatomical characteristics that the penile skin is divided into two layers, the blood vessels of the two layers can be easily separated and the scrotal longitudinal septum has homogeneous blood flow, and the junction of the two is rich in vascular branches. It is suitable for scrotal and perineal suburethral cleft, but not for circumcision and penile skin insufficiency. Complications of applying scrotal flap urethroplasty: the early stage after surgery is mainly local tissue edema, hematoma, bleeding and infection, and the late stage is mainly urethral skin fistula, anastomotic and urethral stenosis, urethral diverticulum, and new urethral hair stone formation.
5.Transverse (Duekett) or longitudinal (Hodgson) foreskin island flap urethroplasty
This method is suitable for those whose urethra is located at the middle or proximal end of the penile thousand and whose dorsal foreskin is ample. The method is performed distal to the urethral opening. A circumferential incision is made 5 mm proximal to the coronal sulcus, the urethral plate is cut, the penile skin is removed over the dorsal neurovascular bundle to the root of the penis, the ventral side of the penis and the fibrous cords around the urethral orifice are removed, the downward curve is fully corrected, and the end of the urethra is trimmed to the developed part of the corpus cavernosum so that the external orifice is beveled. The inner foreskin plate is cut transversely or longitudinally and the vascular tip supplying blood flow to the flap is separated to form a tipped flap, which is rolled and sewn around the stent to form a new urethra in the shape of a tube, a hole is separated at the root of the tip, and the penis is passed through or the tipped tube is passed around the side of the penis and transferred to the ventral urethra, with one end anastomosing obliquely with the original urethral opening. The other end is tunneled under the head of the penis and anastomosed with the head of the penis to form an orthotopic urethral orifice, and the dorsal flap is transferred to the ventral side to repair the wound. In case of perineal hypospadias, a “U” shaped incision can be made around the urethral orifice, and a section of scrotal skin can be freed to make an anastomosis with the tipped foreskin dermatome, i.e. Duckett or hodgson plus Duplag urethroplasty.
6.Free substitute urethroplasty for hypospadias
Today, free substitution urethroplasty is not a mainstream procedure, but it is still reported at home and abroad. Recently, the free substitutes are mainly bladder mucosa, buccal mucosa, free inner foreskin plate, testicular sheath and so on. Among them, only the testicular sheath for urethroplasty, postoperative results are better, less complications, good blood supply of the tipped testicular sheath, stable structure, poor contractility, less scar formation, does not affect penile straightening due to the scar contraction of the flap, the skin tube is smooth with the original urethra, not easy to form diverticula, reconstruction of the urethra to repair hypospadias with testicular sphincter at the same time, the efficacy is exact, simple operation.
7, preservation of urethral plate urethroplasty.
Main procedures.
(1) Covered island flap method: based on Duekett transverse foreskin island flap urethroplasty. This method can be used for cases with well-developed urethral plate, urethral orifice located in the middle and posterior I/3 of the penile body or at the root of the penis, without penile curvature or with mild penile curvature, and with good glans development. The main principle is to preserve a urethral plate, transfer the tipped foreskin flap to the ventral side of the penis to cover the urethral plate and suture it to form a new urethra, avoiding the circumferential anastomosis of the proximal urethra, with few complications such as postoperative urethral fistula and urethral stricture and good appearance.
(2) Urethral plate longitudinal coiled urethroplasty: also known as Snodgrass procedure, it is suitable for the treatment of hypospadias of coronal type, penile body type and part of penile scrotum type. By cutting the flat urethral plate dorsally and medially longitudinally, it allows for freeing and expansion to the sides and ventral side, and allows for tension-free wrapping around the catheter to form a urethra. Compared to the Mathieu and Onlay urethroplasty method, this procedure not only takes less time, but also creates a more aesthetically pleasing penile head and urethral opening. For those who fail after urethroplasty and have very little skin left, urethral plate longitudinal coil urethroplasty is especially suitable.
8. Repair of hypospadias with tissue engineering materials.
Experimental studies using tissue engineering materials have developed considerably in the last five years, but clinical studies are still relatively few.
Today, there are numerous methods of urethral repair and a variety of new materials are emerging, and there are no less than 300 types of urethroplasty alone, but they are not yet perfect. Therefore, it is crucial to select the appropriate repair material for the condition and to be flexible with surgical techniques in order to adopt an individualized treatment plan. This requires the clinician to have a good understanding of the characteristics of each material and the advantages and disadvantages of each surgical method. With the advent of the Snodgrass method, the surgical treatment of hypospadias has undergone a relatively significant change, and urethroplasty with preservation of the urethral plate may become the main procedure for repairing hypospadias.
Factors that affect the efficacy of hypospadias surgery.
1. Age: The younger the child, the higher the success rate of surgery. The younger the child, the more successful the surgery will be. The younger the child, the more vigorous the growth and development, and the easier it is for the new urethral skin tube to survive. As the child grows older, the morning erection phenomenon becomes more obvious, which can easily cause excessive tension and overall collapse of the newly made urethral skin tube.
2.Surgical treatment of hypospadias: The surgical treatment of hypospadias should be based on the presence or absence of hypospadias, the position of the urethral opening and the specific condition of penile development.
3 .Urethral hypospadias typing: The success rate of surgery for mild hypospadias is higher than that for moderate and severe hypospadias. In addition, most of the flaps used in mild hypospadias are from the foreskin, so there is less postoperative secretion and fewer complications of infection, which is beneficial to the survival of the urethral skin tube.
4, postoperative factors: postoperative infection and postoperative combined bladder spasm is the main killer affecting the success of hypospadias surgery. After puberty, the development has basically matured, the urethral secretion is more, and the chance of infection increases; after infection, the flap of the newly made urethral skin tube is difficult to survive, and often forms small local leakage. If the bladder spasms, the urine can flow out along the catheter, and the pressure will open the suture of the skin edge, resulting in total failure. If there is a combination of infection, it will accelerate the failure of suburethral cleft surgery.
5, other: the surgeon’s proficiency in surgical methods and basic operations, the surgical thread used for intraoperative suturing, and so on.
Pre- and post-operative care: 1.
1, before and after surgery the child’s hygiene, health habits and cultural upbringing is very important to prevent contamination of the surgical area. Most of the patients with hypospadias are school-age children, who are not cooperative because of pain and injury, and the location of the incision is easy to contaminate, so it is necessary to do a good job of each care, but also according to the psychological characteristics of children, reasoning, and use the psychology of children afraid of pain and bleeding, and teach them how to cooperate with treatment. Before the operation, we should briefly introduce to the patient’s relatives about the operation method and nursing knowledge, and explain the areas that need to be cooperated with and give guidance. After the operation, we should instruct the children to control urination and defecation as much as possible and not to hold urine. At the same time, family members should help the child to keep the area around the wound free from contamination, and give perineal irrigation and disinfection in time after defecation. The child should also rest in bed as much as possible, reduce activity, keep the ureter open, and do not pull the sutures of the fistula to avoid bleeding and hematoma. The careful preoperative preparation of the operating area and the strict postoperative protection measures cannot replace good hygienic habits and cultural cultivation, and children and their families with good hygienic habits and cooperative care have fewer postoperative complications and a greater chance of successful surgery.
2.Prevention of incisional infection is the key to ensure the success of surgery. It is divided into preoperative preparation and postoperative care. Before surgery, sweat hair should be removed from the umbilicus to the anus, and the vulva should be washed with 1:1000 Neosporin solution for 20 min every day for 3 days before surgery, and clean clothes and pants should be changed after bathing. This will minimize the germs in the operative area. A clean enema should be given the night before surgery and the morning of surgery to prevent the wound from being contaminated by defecation in the short term. To protect the wound after surgery, the wound was exposed and kept dry on the second day after surgery, and the wound was rubbed with 3% boric acid and ethanol at regular intervals to remove blood and scabs from the incision. To reduce the number of stools in children after surgery, a dregs-free liquid can be given. After surgery, the wound should be removed regularly with a syringe and gently squeezed with a cotton swab from the perineum to the top of the urethra, so that urethral secretions can be removed as much as possible, which is important to prevent wound infection and urinary fistula. The surgical area should be kept sterile during sleep and rest, usually protected with a support frame around the surgical area and covered with a sterile towel sheet.
Timely management of urinary fistula is an important part of successful surgery that cannot be ignored. Because of the thinness of the mediastinal flap used for the newly formed urethra and the dozens of stitches throughout the urethra from top to bottom, urine or fluid often accumulates in the new urethra and oozes outward from the sutures, so it is very common for urinary fistulas to occur.