Urinary fistula

　　The vast majority of urinary fistulas are caused by injury. In China, it is mainly due to dystocia, followed by surgical injury, and rarely due to other injuries or infections. With the strengthening of maternal and child health care and perinatal health care in China, urinary fistulas caused by delivery injuries have been greatly reduced, while injuries caused by gynecological surgery have increased relatively.

　　1. Delivery injury

　　It is caused by prolonged labor and dystocia. It can be divided into necrotic type and traumatic type. Necrotic type urinary fistula: Due to malposition of the pelvis, abnormal fetal position, and narrow pelvis, the descent of the presenting part is obstructed, leading to dystocia. If the presenting part is incarcerated in the pelvic cavity for a long time, the soft tissues such as the bladder, urethra, and vaginal wall are compressed between the presenting part and the pubic symphysis of the mother, causing ischemic necrosis and shedding of the soft tissues, forming a fistula. If obstruction occurs at the pelvic inlet level, it often involves the area above the cervix bladder triangle or the ureter, causing vesicocervical fistula, vesicovaginal fistula, or vesicoureterovaginal fistula. If the presenting part is incarcerated in the middle pelvis, it often involves the bladder triangle and bladder neck, causing vesicovaginal fistula or vesicourethrovaginal fistula. If the presenting part remains in the pelvic outlet for a long time, it often involves the urethra, causing urethrovaginal fistula and vaginal annular scar stenosis. Traumatic type urinary fistula: The use of forceps assistance in labor when the cervix is not fully dilated and the bladder is not empty, as well as the rough operation without following the standard operation procedures in other obstetric surgeries such as craniotomy, feticide, vacuum extraction, internal version, etc., can cause damage to the vaginal wall, bladder, and urethra. During cesarean section, the incision of the uterus may tear and extend, causing damage to the bladder, or during the suture process, the ureter may be ligated and the bladder wall sutured through, without discovery and treatment during the operation, resulting in urinary fistula.

　　2. Gynecological surgery injury

　　Gynecological surgery in the pelvis, whether performed abdominally or vaginally, such as radical hysterectomy for cervical cancer, adnexectomy, and total hysterectomy, can cause damage to urinary tract organs and lead to urinary fistula.

　　3. Drug corrosion injury

　　Placing corrosive drugs in the vagina, such as alum, can cause local tissue corrosion, necrosis, and ulceration, eventually leading to urinary fistula.

　　4. Cancer erosion or injury after radiotherapy

　　Advanced cervical cancer or vaginal cancer can directly invade the bladder wall and urethra or lead to local tissue necrosis and shedding after radiotherapy, forming urinary fistula. Urinary fistula after radiotherapy can occur within 1 to 2 years after radiotherapy or even 10 years later. Other gynecological tumors such as gestational trophoblastic tumors, ovarian cancer, corpus cancer, etc., can also directly invade the ureter and bladder, causing urinary fistula.

　　5. Other factors

　　Vulvar trauma or pelvic fracture can damage the urethra and bladder, leading to urinary fistula. Bladder tuberculosis and bladder stones can also induce urinary fistula. Long-term placement of a pessary in the vagina can lead to impaction, tissue compression, ischemia, and necrosis, resulting in urinary fistula.

　　Urinary fistula can be complicated by urinary tract infection, bladder stones, and secondary amenorrhea, but the exact cause is not yet clear.

　　1. Secondary infection of the vulva, buttocks, and inner thigh skin can occur due to long-term exposure to urine, leading to varying degrees of dermatitis, rashes, and eczema, causing local itching and burning pain. If scratched, secondary infection can occur, leading to boils. Urinary incontinence patients may sometimes have varying degrees of urinary tract infection symptoms. If there is a ureteral fistula with local ureteral stenosis leading to renal pelvis dilation and hydroureter, infection is more likely to occur. Some may first form para-peritoneal urinary extravasation, accompanied by infection, and then develop vaginal urinary leakage, which occasionally occurs after radical hysterectomy for cervical cancer.

　　2. In patients with secondary amenorrhea and infertility due to urinary incontinence, 1/2 to 1/3 have secondary amenorrhea, but the exact cause is not yet clear. Some believe it is due to low ovarian function caused by psychological factors, no ovulation during urinary incontinence, and ovulation can resume after repair and cure. The menstrual cycle can be restored.

　　3, Mental and neurological symptoms Patients with urinary fistulas dribble urine day and night, regardless of hot summer or cold winter, wetting their clothes and bedding, emitting the smell of urine. Some may also have feces leakage, making the smell even worse. They often dare not go out to participate in group activities or labor, nor do they want to visit relatives and friends, which seriously affects their work and study. Those with vaginal scar stenosis or obliteration lose the ability to have sexual life and childbearing, which also affects the couple's feelings and family relationships. Some patients cannot bear the long-term physical and mental torture and even have thoughts of suicide.

　　Urinary fistula is one of the most painful diseases for women, and its common manifestations are as follows:

　　1, Urinary incontinence

　　Urine continuously flows out through the vagina, and in unilateral ureterovaginal fistulas, there is still spontaneous urination. However, in large bladder-vaginal fistulas, there is no spontaneous urination. Urethro-vaginal fistulas only have urine flowing out through the vagina during urination.

　　2, Urinary eczema

　　Due to long-term stimulation by urine, the perineal and perianal skin becomes red, swollen, and thickened, and sometimes there are papules or superficial ulcers. The vulva is itchy and painful.

　　3, Menstrual disorders

　　10% to 15% of patients have long-term amenorrhea or decreased menstrual flow.

　　4, Depression

　　Due to long-term dribbling of urine, the clothes and pants are soiled, the smell of urine is everywhere, and it is difficult to live with others. At night, the bedsheet is damp, sexual life is impaired, and some may even become depressed or even have a desire to end one's life.

　　Strengthening perinatal care and continuously improving the quality of obstetrics and gynecological surgery techniques can largely prevent most urinary fistulas. Birth trauma is the main cause of urinary fistula in developing countries. In the prevention of birth trauma-related urinary fistulas, emphasis should be placed on family planning, strengthening the systematic management of pregnant and postpartum women, conducting regular prenatal examinations, early detection of pelvic narrowing, deformities, or abnormal fetal positions, timely correction, and early hospitalization for childbirth. Close observation of the labor process should be strengthened for pregnant women, and any abnormal labor curve or prolonged second stage of labor should be handled promptly to end labor as soon as possible to avoid dystocia. Before vaginal surgery, it is routine to perform catheterization to empty the bladder, strictly follow the operation procedures during the operation, and carefully use various instruments. When sharp instruments or bone fragments from amputated limbs pass through the vagina, the vaginal wall must be protected. After surgery, a routine examination of the reproductive and urinary tracts for any injury should be performed, and any injury found should be repaired immediately. For those with prolonged labor, urinary retention, or a history of hematuria, a catheter should be left in place for about 10 days after delivery to prevent the formation of urinary fistulas. Patients with urinary fistulas who have been cured should undergo cesarean section during subsequent childbirth. In terms of preventing gynecological surgery injuries, fully estimate the difficulties in surgery, grasp the links that are easy to cause injury, be familiar with the anatomy and variations of pelvic organs, and improve the basic technical skills of surgical operations. When adhesions are severe in pelvic surgery, the adhesions should be carefully separated first to restore the normal anatomy of the organs. During total hysterectomy, the bladder should be pushed down to the level of the external os of the cervix, especially the lateral angles to the lateral margin of the cervix by 1 cm. Constant attention should be paid to the course of the ureters, and it may be necessary to mobilize the ureters and trace their pelvic course to avoid injury. Radiotherapy should avoid excessive dose. The use of pessaries should adhere to daily removal at night and not be placed for a long time.

　　Urethral fistulas are more common in women of childbearing age, and the following examinations need to be done:

　　1. Cystoscopy

　　Understand the number, size, and location of the fistula, the relationship between the fistula and the ureteral orifice, and the urinary bladder orifice, and understand the bladder capacity, whether there is inflammation, stones, diverticula, etc.

　　2. Methylene blue test

　　It can distinguish between vesicovaginal fistula or ureterovaginal fistula. After injecting diluted methylene blue into the bladder, if the cotton ball in the vagina turns blue, it indicates a vesicovaginal fistula; if the cotton ball in the vagina does not turn blue, and there are small fistulas, it indicates a ureterovaginal fistula.

　　3. Indocyanine green test

　　Inject 5ml of indocyanine green, and after 5 to 7 minutes, blue liquid can be seen to溢出 from the fistula, which is suitable for the diagnosis of congenital ureteral orifice ectopia or ureteral fistula.

　　4. Intravenous urography

　　Understand the condition of the upper urinary tract, determine the location of the ureteral fistula and renal function.

　　Patients with urinary fistula should avoid spicy and irritating foods such as spicy hotpot, horseradish, raw garlic, ginger scallions, chili, etc., and are prohibited from smoking and drinking, otherwise internal heat will worsen. Triggers can exacerbate inflammatory conditions, and it is necessary to avoid all triggers, such as special meats like pork head, goose meat, chicken feet, etc., seafood like flatfish and crabs, and legumes like peanuts. However, this condition is different from allergic diseases of a similar nature, and there are no excessive requirements for protein intake. However, eating too much meat can make urine acidic, which is not conducive to the control of the condition. It is best to eat more vegetables and fruits to make the urine alkaline, enhancing the effectiveness of antibiotics. It is necessary to drink plenty of water, as large amounts of water are beneficial to the treatment and recovery of urethritis patients.

　　The main method of urinary fistula treatment at present is surgery. Due to different causes of fistula and varied conditions, non-surgical therapy can be tried in some cases before surgery, and if treatment fails, surgery can be performed. In addition, for those who are not suitable for surgery, urinary collectors should be used for treatment.

　　1. Ureterovaginal Fistula

　　Ureterovaginal fistulas that appear within 1 week of surgery, if ureteral catheters or double-J tubes can be inserted into the damaged site above the bladder scope, and retained for more than 2 weeks, there is a possibility of healing. Ureterovesical transplantation surgery can be performed if the fistula is low, and if the remaining ureteral length is not enough to directly anastomose with the bladder, then perform bladder muscle flap formation and anastomosis with the ureter. Ureterocutaneous stoma is more suitable for patients with lower urinary tract obstruction and bladder contraction.

　　2. Cystovaginal Fistula

　　Smaller fistulas occurring within 1 week can have a catheter left in place for more than 2 weeks, and the catheter should be kept unobstructed to allow for the possibility of spontaneous healing. If it does not heal, surgical repair is performed, often using cystovaginal fistula repair. Generally, repair surgery is performed 3 months after the injury. If it is a low-positioned cystovaginal fistula, it can be repaired through the vagina; a high-positioned small cystovaginal fistula can be repaired through suprapubic vesical repair; a high-positioned large cystovaginal fistula requires repair through the posterior vesical wall; complex cystovaginal fistulas should be repaired through a combined abdominal and vaginal approach; if necessary, through the pubic approach. To ensure the success of the surgery, adequate preoperative preparation should be done, and the vagina should be flushed with 1:1000 benzalkonium chloride solution for 3 days before the operation and infection should be controlled; the surrounding tissue of the fistula should be adequately freed up, hemostasis must be thorough, and the suture must be tension-free; if the fistula is too close to the ureteral orifice, ureteral transplantation may be required; postoperative catheterization should be maintained.

　　3. Urethrovaginal Fistula

　　For smaller vesicovaginal fistulas, the fistula can be cauterized with phenol through the vagina, and a catheter can be left in place; for larger fistulas, the vagina can be repaired, and the sutured fistula should be as close as possible to the three layers of urethral mucosa, urethrovaginal interstitial tissue, and vaginal mucosa; layered suture to reduce the failure rate of urinary fistula repair.