Urethral fistula

　　Urethral fistula generally forms during the embryonic period. In the 8th week of embryogenesis, the primitive genital tubercle of the lower anterior abdominal wall shifts backward too much, and the position of the urogenital sinus duct, which connects to the terminal end, is too forward. This causes the urethra to form on the dorsal side of the penis. If the urogenital sinus duct does not converge at the midline, it forms an urethral fistula. According to the opening position of the urethra on the dorsal side of the penis, male urethral fistula can be divided into 3 types.

　　1. Glans penis shape

　　The opening of the urethra is located in front of the dorsal coronal sulcus of the glans penis.

　　2. Penis shape

　　The opening of the urethra is located at any position between the dorsal side of the penile body, the root of the penis, and the coronal sulcus, which is the most common type.

　　3. Complete type

　　The urethral opening is at the bladder neck, and some even have varying degrees of ectopia vesicae and pubic symphysis separation, with underdeveloped external urethral sphincter and neck muscles of the bladder.

　　Female urethral fistula is divided into clitoral type, subpubic type, and complete type. The main manifestations are clitoral splitting, separation of the labia majora and minora, and pubic separation. The complete type is accompanied by urinary incontinence.

　　Pathogenesis

　　The pathological changes of urethral fistula include the following four aspects:

　　1. Abnormal urethral position located above the corpus cavernosum on the dorsal side of the penis.

　　2. There is a degree of defect in the anterior wall of the urethra. The defect part of the urethra is grooved, covered with urethral mucosa.

　　3. Penile malformation The glans penis is flat and wide,呈铲状, with the corpus cavernosum separated, the penis is short, and the prepuce is lacking on the dorsal side and abundant on the ventral side.

　　4. Developmental disorder of the urethral sphincter causes urinary incontinence and atrophy of the bladder due to disuse.

　　Urethral fistula refers to the partial or complete absence of the urethral dorsal wall, covering the dorsal side of the penis and extending to the bladder, where a wide mucosal strip replaces part of the normal urethra. It often appears as part of ectopia vesicae and cloaca. The possible etiology of urethral fistula is still unclear. Simple male urethral fistula is rare, with an incidence rate of only 1 in 117,000 reported in males. Urethral fistula often occurs with ectopia vesicae and urinary tract infection.

　　Congenital urethral malformation is a congenital abnormality formed before birth, mainly including hypospadias, urethral fistula, diverticulum, posterior urethral valve, and congenital urethral orifice stenosis. Infants have severe systemic symptoms, such as underdevelopment, anorexia, nausea, vomiting, fever, dehydration, and so on. During physical examination, distended bladder or enlarged kidneys may be found. Children over 1 year of age have severe urinary disorders. Symptoms such as crying, effortful urination, and even the need to press the lower abdomen with the hand to urinate, with a thin urinary stream and sometimes overflow incontinence. Those who have lumbar pain during urination often have vesicoureteral reflux.

　　Urethral fistula occurs in the early embryonic stage and is caused by an abnormal migration process of the primordium of the genital tubercle to the cloacal membrane. The specific cause is not yet clear, and it often occurs with ectopia vesicae. A single urethral fistula is a relatively mild type of this malformation. The following is an introduction to the symptoms of urethral fistula:

　　(1) Abnormal Urethral Opening Position

　　The opening of the male urethra can be located between the pubic symphysis and the top of the penis. Abnormal urethral opening in females is located between the clitoris and the labia, with the distal urethra absent.

　　(2) Urinary Incontinence

　　The severity of male urinary incontinence mainly depends on the degree of dorsal ectopic urethral orifice defect. 90% of female patients have urinary incontinence. The causes of urinary incontinence include: loss of urethral sphincter; underdeveloped bladder with small capacity; decreased urethral resistance.

　　(3) Malformation of External Genitalia

　　Male patients have poor penile development, with a flat glans penis, a short and wide corpus cavernosum, split prepuce on the dorsal side, and often accompanied by penile shortening and bending backward. In females, the mons pubis flattens and descends due to pubic symphysis separation, the prepuce of the labia majora and minora separates, the labia minora are underdeveloped, and the clitoris and prepuce split.

　　(4) Pubic symphysis diastasis

　　Only fibrous tissue connects the pubic bones, and the distance between the ischial tuberosities increases.

　　(5) Reflux nephropathy

　　Some patients may have associated anomalies, leading to vesicoureteral reflux.

　　(6) Urinary tract infection

　　Most patients can have urinary tract infections.

　　(7) Sexual dysfunction

　　Male patients, due to the bending of the glans penis towards the abdominal wall, most cannot have sexual intercourse. Some have good seminal function, while others, due to the inability of the bladder neck to close, seminal fluid refluxes into the bladder.

　　Urethral cleft seriously affects the patient's daily life, so it should be actively prevented. Since urethral cleft occurs during the embryonic period and the triggering factors are not yet fully clear, there are currently no effective preventive measures.

　　The symptoms of urethral cleft are relatively obvious and can be diagnosed by the naked eye without special examination. It can also be further diagnosed by auxiliary examinations.

　　1. Pelvic X-ray

　　It can determine whether there is pubic symphysis diastasis and its degree. Intravenous urography can determine urinary tract function and morphology, as well as whether there are other urinary tract anomalies.

　　2. Cystoscopy

　　It is very helpful for determining incontinence, where incontinent patients may have a wide posterior urethra and an incompetent bladder neck.

　　3. Contrast examination

　　Urography: Excretory urography, also known as intravenous pyelography.

　　Posterior peritoneal pneumography.

　　Abdominal aortic-renal artery angiography.

　　Ectopic ureter orifices mostly occur in patients with duplicated kidneys and double ureteral anomalies, and most ectopic ureteral orifices come from the upper pole of the duplicated kidney.

　　The formation of urethral cleft has nothing to do with dietSurgical correction is required, but preventive infection treatment can be given in terms of diet before surgery..

　　Drink more water

　　Drinking water can increase urine output and has a cleaning and flushing effect on the entire urethra, helping to expel pathogenic bacteria from the urethra. It also dilutes urine, reducing the irritation of high-concentration urine to the kidneys and urethra.

　　Eat more fresh vegetables and fruits

　　Especially eat more radish, at least four times a week. Radish has a high water content and can increase urine output, and it is also rich in vitamins, which can help repair the urinary tract epithelial cells and enhance the body's ability to resist diseases.

　　Eat more winter melon

　　There is also a food that must be eaten, which is winter melon. The cooking method of winter melon is quite particular, and generally, slow cooking is the best. It is recommended to have it three times a week or more. Winter melon has a diuretic effect, which not only cleanses the urethra but also has a cleaning effect on the whole body's metabolism. It helps to expel toxins from the body.

　　Patients with urethral cleft need to pay special attention to their diet after surgery. They should consume more smooth, fluid foods such as milk, fruit juice, vegetable juice, broth, and various nutrient fluids, which should be high in nutrition, calories, and protein, and low in fiber. This not only promotes incision healing but also helps to control defecation appropriately. It is advisable to avoid eating greasy foods, as they can reduce intestinal motility and are not conducive to the formation of stool. It is important to drink plenty of water regularly to maintain the通畅 of the urinary tract.

　　治疗尿道上裂需达到2个目的，即达到正常排尿、维持正常的性交及生殖功能。为了达到这些目的必须进行：膀胱颈成形、矫正阴茎畸形及尿道重建。

　　1、膀胱颈成形

　　这是治疗尿失禁的主要手段，但也是一个非常棘手的问题。在2～3岁以前由于尿道括约肌发育尚不十分完善，并存在着自然遗尿现象，很难确定尿失禁程度，膀胱颈成形后亦难观察疗效。因此，膀胱颈成形应待病儿稍长，能有意识进行排尿后施行为好。可用Leadbetter术式做膀胱颈缩紧，延长尿道。用膀胱三角区的全层肌层，做成平滑肌管。切除原有膀胱颈及后尿道背侧的纤维组织，再将其合成管状，使管腔缩小，以形成新的膀胱颈及后尿道。由于术后90％的小儿都发生膀胱输尿管反流，故于缩窄膀胱颈的同时做防反流的输尿管膀胱再吻合术。也有的用膀胱前壁行膀胱颈尿道成形术，可避免行输尿管膀胱再吻合术。膀胱颈成形术后，仍需经过一段时间的排尿训练，能达到正常排尿。

　　2、矫正阴茎畸形

　　一般主张在性成熟后再行阴茎畸形矫正术。矫正阴茎畸形主要包括2个方面的问题：

　　①伸长阴茎。

　　②矫正阴茎下弯。

　　如阴茎发育不好，应首先用雄激素治疗，待其发育后再行手术。手术时将左右两侧的阴茎悬韧带切断，阴茎方能伸长。将尿道黏膜与阴茎完全分离，直达精阜，阴茎才能伸直。保留尿道黏膜，包皮不得切除，留待行尿道成形术用。

　　3、尿道形成

　　大部分学者用尿道沟的黏膜条或尿道沟周围的皮肤行尿道成形术。也有的主张用包皮皮肤。无论用什么方法，新形成的尿道应置于腹侧两个阴茎海绵体之间，并应将2个分离的阴茎海绵体缝拢，在行尿道成形术时，需行耻骨上膀胱造瘘。